Indium Corporation Blogs

It is no secret that automotive semiconductor customers are becoming increasingly demanding. The "under the hood / bonnet" electronics environment is arguably one of the most thermally stressful environments on the planet. Electronics close to the engine block can experience extremes ranging from frigid winter cold to tropical heat, with the added heat source of the adjacent internal combustion engine.

The moisture sensitivity level (MSL) standard from JEDEC / IPC was developed to cover the moisture-absorption and "popcorning" effects of polymeric overmolded materials, but has been expanded in usage to cover a variety of different packaging situations and failure modes. The standard does allow for a certain amount of delamination, even under the MSL1 conditions usually required by automotive semiconductor customers. However, now "zero tolerance for delam" is the most common request from automotive design engineers. In order to meet this need, both overmolding materials manufacturers and leadframe suppliers have been working on how to drive to zero delamination. Leadframe manufacturers have developed a variety of approaches to their products that enhance the adhesion between the leadframe metal itself and the overmolding compound. Usually, this takes the form of physical and chemical texturing of the copper, using a process such as brown oxide formation.

It is no surprise that this need for adhesion enhancement (AE) drives leadframe treatments that are antithetical to the need for formation of void-free, high conductivity electrical connections between the die and the leadframe - basically, it messes with the solderability of the preform or solder paste. In order to get around this issue, leadframe manufacturers have increasingly moved to the use of spot-plating of silver onto copper, with thicknesses ranging from 2-9microns. Why is the silver so thick, in comparison to silver sputtering onto the die surface? Simply because copper diffuses very quickly into the silver, so a thicker silver layer leads to a longer shelf-life for the leadframe. Note also that plating does not have as good process control as sputtering, but it is a lot cheaper and faster.

You can see (below) a schematic of solder paste printed onto one of these leadframes.

An emerging failure mode is one of incomplete wetting onto the leadframe, leading to failures at the sites where solder has failed to flow over the silver plated area completely - "delamination sites" - (below). The flat, shiny, silver finish is not a suitable surface for overmolding compounds to bond to.

So why isn't the solder wetting well? The answer becomes clear pretty quickly when you do some back-of-the-envelope calculations of the expected final silver content of the finished joint. Let's assume some bondline thicknesses (BLT) is (25,75microns) of a solder containing 2.5%Ag (such as Indalloy 151 or 163) and the plating thickness is (3-9)microns. Typical plating thicknesses of 2-9microns may be seen, based on a recent customer survey), with a mean around 3microns.

So what is the silver content of the final joint, assuming all the silver is dissolved?

The calculations, therefore, show that it is from 6 to 27% silver. The 27% level is well beyond the solubility limit of silver in these types of solder, and in fact in most solders, at the expected soldering temperatures. The mechanism of non-wetting is clear: solder can no longer wet onto silver, once it has become filled with insoluble intermetallic particles.

The message to power semiconductor component suppliers is:

• Maintain the silver thickness at a consistent, low level: set up tighter specifications on the silver spot-plating from your supplier.
• Update your incoming quality control inspection so you can be sure you are getting what you paid for in terms of thickness of silver and consistency.
• Manage leadframe inventory so you run leaner, so you do not run into leadframe lifetime issues with copper diffusing through the thin silver layer and oxidizing (solderability / voiding problems).

You do have an alternative (moving to an alternate solder type), but then you are into a lengthy requalification procedure.

As always, please contact me if you need assistance.

Cheers!  Andy

Folks,

I am a global warming skeptic.  This term, however, requires some explanation.   I believe in climate change.  The climate is always changing.  However, I don’t think it is clear that the world has been getting warmer in the last decade.  I also am not convinced that humans are the main drivers of whatever  climate change has occurred.  The following explains why.

Point 1: For the Last 12 years the World Not Getting Warmer

The global warming scenario that exists today is that human emissions of carbon dioxide are the main reason that the climate is warming.  So, it is natural then to ask, is the climate really warming?  One look at USA Today’s cover story “Why You Should Sweat Climate Change” on 1 March 2013 would appear to settle the story.  Just look at  Figure 1 below.

Figure 1. Graph from USA Today Cover Story March 1,2013.

A quick scan of the graph shows 55.34°F last year and 50.56°F in 1895.  A 5 degree increase.  Wow!  A little closer analysis reveals that these temperatures are individual data points.  If you look at the years 1900 and 2010, you get 53°F for both years, essentially no change.  The thick red line is the long term trend and admittedly it increases from about 51.3°F to about 53°F in the 117 year period. 

Note the icon in the upper right corner, it shows the globe with a dramatic upward trend line.  However, this causes you to now note that this graph is for US temperatures, not world temperatures.  What was the world temperature like?  As this thought crosses your mind, you remember that 2012 brought Europe its coldest winter in recent memory. So you go on the internet and find out that 2012, for the world,  was the ninth hottest year on record.  Scary.  But then you think, “Wait a minute, that means that eight years were hotter.” So you wonder, what do the last 10 or so years look like for world temperatures.  The graph is below in Figure 2:

Figure 2. World Temperature 2001-2012. Graphed by Dr. Ron

Note that for the last twelve years, the trend is flat (actually a little down).  Where are all of the headlines sharing this important information?  So it is not clear that the world is continuing to get warmer.  

Am I the only one that finds it troubling that the media seem to universally tout the scary stories about global warming, but don’t seem to mention obvious counterpoints such as the graph above?  This information is profoundly important.

Point 2: In the Past, Nature Along has Delivered Stunning Climate Change by Itself

I am writing this post from my home Woodstock, VT. I look out my window and view two beautiful, large rocks, each about the size of a house.  These monoliths were likely left as the glaciers in the last ice age retreated, these rocks probably originated in Quebec.  Woodstock was under thousands of feet of ice during the last ice age, Canada was completely under ice.  New York State's Long Island is a glacial terminal moraine. The extent of the ice coverage is shown in Figure 3 below.  However, the forces of nature alone, raised the temperature of the earth by 12 degrees Celsius (with no help from mankind), melting the glaciers and allowing me to live in the Green Mountain State (Vermont = Ver (green) mont = mountain, in French.)  

Figure 3. The Extent of the Ice Coverage in the Last Ice Age  http://www.iceagenow.com/

The natural processes that caused the warming are many.  They include the precession of the earth on its axis, variation in the output of the sun, changes in the ocean and atmosphere, and others.  These processes  have resulted in the past temperature changes as shown in the Figure 4 below.

Figure 4. Temperature of the Earth in the Past 800,000 Years.

This figure shows as much as a 20°C (36°F!) temperature swing produced by nature alone.  The change in world temperature between 1900 and 2010 would be about as thick as the line in this figure. 

I find the proposition that the main driving force in global warming (if it is occurring)  being human produced CO₂ alone is hard to accept, when we see what mother nature has given us in the past.  It would be similar to someone taking the position that the only thing that affects stencil printing quality is the stencil.  When others point out that it might be the solder paste, or the print head, or separation speed, etc., they are shouted down as being unscientific.

Point 3: It was Warmer in the Middle Ages than Today

The United Nations commissioned a panel to study climate change in 1988.  The Intergovernmental Panel on Climate Change IPCC  was established.  In 1990, the panel came out with an assessment of past world temperatures as shown below in Figure 5.  The estimating of temperatures before the mid 1800s is difficult due to lack of records and thermometers before this time.

Figure 5. The First IPCC Assessment of World Temperatures, 800AD to the Present

There is some argument that the Medieval Warm period and Little Ice Age were local events, however they clearly existed and profoundly affected much of the Northern Hemisphere.  But more recent temperature IPCC plots lose them, as seen in Figure 6. below.   The Medieval Warm Period enable the Vikings to settle in Greenland and red wine to be grown in England. When the Little Ice Age came, the Vikings had to leave and England has not been as warm since. 

Figure 6. Third IPCC Temperature Assessment.  Note the Medieval Warm Period and Little Ice Age Disappear.  Because of the abrupt change in temperature after 1900, this graph has earned the moniker, The Hockey Stick Graph.

The controversy over the Hockey Stick graph  is interesting reading and is the source for Figures 4-6.  

In 2003, MacIntyre and McKitrick presented a detailed criticism of the IPCC 3^rd Assessment's Hockey Stick Graph in Figure 6 .  I find their criticism compelling.

I could go on and on,  but to summarize why I am a global warming skeptic:

• For the  past decade the world has not gotten warmer
• Natural forces overwhelm CO₂ as a driving force for climate change
• Sloppy science is behind the hockey stick graph

Please share your science- and fact-based comments.

Cheers,

Dr. Ron

One question that I often hear from customers is; “Once out of the refrigerator, how long do I have to wait to allow my solder paste and/or flux to reach room temperature in order to use it?”

It is indeed very important for solder pastes and fluxes to be at ambient temperature (approximately 23^oC) in order for them to exhibit optimal performance, as the rheology of these materials will differ in a refrigerated state. Additionally, "cool" materials condense atmospheric moisture onto their surfaces (like a glass of cold water in the humid summer air). This condensed moisture is an unwanted ingredient in high quality soldering.

In order to quantify the amount of time necessary for these materials to reach room temperature, we refrigerated both solder paste and flux in 6oz cartridges.  We then recorded the time it took to reach room temperature by placing thermocouple leads in the center of the materials through small holes that were drilled in the containers.

The following is a graph of the time versus temperature of warming both paste and flux:

For the testing above, the ambient temperature was approximately 22-24^oC.  The flux required approximately 2.5 hours to reach room temperature, whereas the solder paste required approximately 2 hours.  It would be expected that the solder paste would reach room temperature faster than flux alone, as the metal content of the paste increases the thermal conductivity of the material. 

Of course, your particular conditions (refrigerator temperature, container size and shape, ambient temperature, etc.) will make your situation somewhat different.

For questions regarding the proper handling and storage procedures for solder materials, please contact Askus@indium.com.

Folks,

Let’s see how Pete is handling the wave solder crisis.

Pete had to admit that he was surprised by the positive outcome of his meeting with Fred Castle.  He had sent Patty a text the day before, after he took the operators to lunch, before meeting Fred.  The text was a little negative.  So he was eager to send her the good news about the surprises in his two meetings with Fred since then.  He was frustrated that he kept on getting her voice mail.  Finally she answered.

“Advanced Processes,” Patty speaking.

“Hey, kiddo, it’s your favorite process genius!” Pete responded cheerfully.

“Oh, this must be Oscar Patterson!” Patty joked, and they both laughed. Patterson was an annoying chap they had to deal with a few years ago.  He topped their list of most annoying people. Pete had almost come to fisticuffs with him.

“How is it going there?” Patty asked.

“Shockingly well. My meetings with Fred Castle were very productive” Pete answered.

“Well, that is shockingly positive news. But I thought he said, ‘I’ve forgotten more about wave soldering than you’ll ever know,’” Patty responded.

“That’s the first thing he said to me when we shook hands, but he was clearly teasing.  He slapped me on the back at the same time and chuckled. He went on to say that he had worked in wave soldering for over 30 years, typically at companies that had processes that were out of control.  It was clear that he understood a lot about wave.  We talked for 30 minutes about what makes a good wave process. As far as I could tell he was right on in everything he said.  I think the operators didn’t pick up on his teasing, by the way,” Pete elaborated.

“What about special cause vs common cause?” Patty queried.

“He didn’t have a clue,” Pete replied.

Patty was bracing herself.  She was concerned that Pete might have insulted Castle.

“And you didn’t tell him he was an idiot?’ Patty teased.

“Patricia! I’m shocked you could even think such a thought,” Pete replied.

Pete went on, “We bonded, and he admitted that he was frustrated with the yield loss increasing.  He was studying the situation and spending a lot of time trying to figure out the issues.  He said he was having trouble sleeping.  He mentioned that, in his last job, he was responsible for the wave processes at 10 locations.  He was constantly fighting fires and got good at it.  He had never worked at company that performed DOEs and developed optimized processes.”

“I’m dying to know how this situation worked out,” she interrupted.

“Patience, patience,” Pete admonished jokingly. He continued, ”It was clear that Fred likes to learn, so  I mentioned that, recently, The Professor had mentioned the importance of understanding the differences between common cause and special cause variation when trouble shooting a process.  I suggested that maybe studying these topics might help. So I gave him a few links to The Professor’s posts on common cause and special cause.” (Dr. Ron note, it will be helpful understanding this story to read The Professor's post, if you are not familiar with common cause and special cause fails.)

“What happened then?” Patty asked, the impatience in her voice apparent.

“Remember, this is now the end of my first day. I watched the process in the morning, took Molly and Chuck to lunch, and then met with Fred.  On the second day I had a morning meeting with the quality director, Pam. Then Castle and I went to lunch,” Pete elaborated.

“And?” Patty asked impatiently.

“Castle was all excited.  After studying common cause and special cause all night, he realized that he was seeing common cause fails in his detailed scrutiny of the wave line. By adjusting the process parameters slightly when he found a common cause fail, he was moving away from the optimized process settings that were determined by a DOE, so the failure rate got worse.  In his previous job, he was mostly seeing special cause fails, as the processes were not optimized, so he was used to intervening,” Pete explained.

“It seems like he won’t have enough to do now,” Patty commented.

“I suggested he help quality.  They are stretched thin and he is a detailed-oriented fellow.  He keeps meticulous Pareto charts of the fails,” Pete said.

So, where are things now?’ Patty asked.

“Yesterday and today, first pass yields are at 96%.  Fred also started helping quality today. It felt good to help and not offend,” Pete finished.

Patty thanked Pete for the great job he did and complimented him strongly for being successful and making friends at the same time.  As she hung up the phone, she saw an email from Pam Olinski in her in box.  It was a kind note thanking her and Pete for his help.  It recounted much of what Pete had said.

She wistfully looked out her window.  She was happy and grateful for all of her success, but, to be truthful, she missed the action of being out on the shop floor solving these types for problems.

She was jolted from her chair when she suddenly remembered it was her turn to take her twin sons to karate lessons.  So she packed up quickly to pick them up at her mother-in-law's, to get them to the gym by 5PM.

Cheers,

Dr. Ron

image

Folks,

It's been a while. Let's look in on Patty......

Patty stared, bleary eyed, at her laptop screen.  It was the day after the election.  She and Rob were following the election closely as a “statistical thinking” exercise.  They had met at a conference with The Professor in late October and agreed that following the election would test their statistical thinking skills.  They established beforehand that they would not discuss who they favored, just the data.

All agreed that Mitt Romney had a greater challenge than President Obama.

As Rob said, “Of the six most populated states, even the Republicans agree that Obama will win California (1), New York (3), Illinois (5), and Pennsylvania (6).  Romney is only a shoe-in for Texas (2).  Only Florida (4) is a toss up”

“I thought some analysts were saying that Pennsylvania is in play,” The Professor commented.

“They’re dreaming,” Patty said with conviction.  “Pennsylvania has too many big cities; typical democratic strong holds,” she continued.

“Many pollsters have 255 electoral votes in Obama’s column and only a little over 200 for Romney. It’s hard to see a Romney path to victory.  It is statistically unlikely he could win all of the swing states” Rob added.

The Professor beamed as he listened to his protégés' intelligently analyze and argue the situation.

They all agreed that it was hard to understand why many were referring to it as a close race, although voter turnout could change everything.

As election night went on, Patty felt she could call the election at 8PM EST.  However, she was sympathetic that the networks needed a high level of certainty. The major networks were finally calling it at 10PM.  When they did, Romney was ahead in the popular vote by about 1 million.  Patty chuckled to herself, when a renowned TV anchor commented that it might be a governing challenge to Obama to win the electoral college and not the popular vote.  Clearly he had not factored in the fact that, although California was “called” for Obama around 10PM EST, it was called with only a few percent of the votes in.  The networks were using exit polls and statistical analysis to make a projection.  By the time all of the west coast votes were counted, Obama will comfortably win the popular vote - because of California’s large population.  Patty thought this should be obvious to the pundits.

Patty had stayed up until about 11PM to watch the results.  It was comforting that her analysis was spot on.  However, she was so “wound up” that she couldn’t fall asleep and she was now paying the price.

As her attention shifted back to the email she was writing.

Suddenly, she was jarred by a loud, cheerful voice.

“Hey kiddo, pack your bags, looks like we’re on the road again,” Pete said loudly.

As usual Patty thought,” How does Pete always know these things before I do…..I’m the boss!”

“What’s the scoop?” Patty asked.

“Remember our facility in Ohio?  They are having wave soldering yield and throughput problems,” Pete answered.

“What!” Patty shouted.  “We spent a lot of time there six months ago optimizing their wave soldering operation and teaching them the appropriate use of solder preforms. What happened?” She finished.

“Not sure,” Pete responded. “I thought we worked really well with their team and developed a good process.  It seemed to me it was one of the more productive projects I was involved in in quite awhile,” Pete finished.

“And you didn’t even offend any of the senior managers,” Patty teased.

Pete chuckled but his cheeks did turn a little red.  Pete was a terrific process engineer, but he had a little bit of a “short fuse,” although he was usually right.

“In talking to some of my buddies there, they told me that senior management hired a very senior fellow who is considered an expert in wave.  Strangely, things fell apart right after he joined,” Pete explained.

“Well, you are on your own for this one.  I've got a number of family commitments over the next two weeks,” Patty said with a little sadness in her voice.  Patty enjoyed these types of challenges.

“As soon as I get the official request, you’ll be on your way,” Patty said.

“Oh, and don’t offend anyone,” she teasingly finished.

As Pete left her office, she checked her emails. Sure enough, there was a note from Mike Madigan asking her to intervene in this wave soldering problem.

Two days later Pete was in ACME’s Ohio facility sitting in the office of Pam Olinski, the site's quality manager.

“Pete, I’m so glad you could come.  Three months ago our wave soldering first pass yield was 95% and our production was about 2,000 boards per day.  Yield is now 90% and production is off 15%. “Help!” Pam said.

“Tell me about the new guy?” Pete asked.

“Fred Castle; he has very impressive credentials, but he has been running the wave process like a dictator. He stops the process a lot to adjust the wave machine.  I think he will be offended that you are here to audit the process,” Pam finished.

Because of this concern, they agreed that it might be best to have Pete initially view the process from afar.  So, they decided that Pete would be given an operator’s smock and walk around the shop floor for half a day or so.

As Pete arrived on the shop floor, almost immediately he saw Fred stop the wave machine and make some adjustments.  While  making the adjustments, Fred held a board in his hand - and he looked at occasionally.  After the wave machine was running again, Pete saw that Fred looked carefully at every board.

Pete saw one of the wave operators was going on a break.  Pete remembered Molly Stark from his visit to optimize the wave process six months ago, so he stopped her and ask if she could join in for lunch.

The morning passed quickly, and Pete was off to lunch with Molly.  As Pete had suggested, Molly brought another operator, Chuck Petrus to lunch.  Pete insisted on treating, so Molly and Chuck left their brown bags behind. 

In total, Fred stopped the line four times during the almost 4 hours of Pete's observations. Each time he made adjustments on the wave machine. After exchanging pleasantries Pete asked, “Why was that fellow stopping the wave line so often?”

Molly got quite animated and answered, “That’s Fred Castle, the supposed wave genius. He stops the line every time there is a defect and adjusts the wave machine parameters.  A number of us complained to him that he shouldn’t make adjustments on the machine that with just one fail.  That’s what you taught us.”

“What did he say?” Pete asked.

“ ‘I’ve forgotten more about wave soldering than you will ever know’……No one has said a word since,” Chuck responded.

“You and Patty taught us about special cause and common cause variation. I don’t think Fred understands that,” Molly commented.

“He’s also a knob twiddler,” Chuck added.

Does Fred know the difference between common and special cause variation?  Is that the root of the yield and throughput problems? 

What is a knob twiddler? Stay tuned to find out.

Cheers,

Dr. Ron

Printed circuit boards containing both surface mounted and through-hole components are common, and are often referred to as "mixed technology" boards.  In mixed technology assembly, solder paste is used to attach the components to the surfaces and wave soldering attaches the components that are inserted through holes in the board.  For low volume production, hand soldering is often utilized - for the attachment of through-hole components.  Both of these methods require additional steps after the original reflow of the solder paste.

To increase your profits (saving you time and money while improving your quality and productivity) InTEGRATED PREFORMS^® have found a place in mixed technology assembly.  InTEGRATED PREFORMS^® are interconnected solder washers, designed to fit the pin pattern of a through-hole component.  These arrayed solder washers are sized to deliver the precise solder volume required to fill the holes and to produce excellent solder fillets at each joint. 

In some cases, to add even more solder, solder paste is deposited over the holes and the InTEGRATED PREFORM^® is placed into the paste. The component is then inserted through the solder preform, the solder paste, and the hole. 

In other applications, TacFlux® (that is compatible with the solder paste's flux vehicle) is applied to the preform before it is placed on the component's pins, or is placed directly on the board, and the component is inserted as described above.  Whichever method is used, only one reflow step and only one cleaning step are required.

In traditional wave soldering, components with long pins are a special challenge because they are very difficult to attach without getting alloy on the pins during wave or hand soldering.  InTEGRATED PREFORMS^® can be applied to the top or bottom side of the board and are reflowed along with the components held down with solder paste.

InTEGRATED PREFORMS^®  are designed and built to address the unique characteristics of each specific application.  To build your InTEGRATED PREFORMS® we require the following information, so the solder volume and washer spacing are correct for your specific pin configuration:

• Hole size
• Pin size
• Board thickness
• Center to center spacing of the pins (within the row, and row to row)
• Solder Alloy
• Is the preform going to be used to add to the volume of solder from the paste?

Separate (individual) solder washers can also be used in place of connected InTEGRATED PREFORMS^®.  They can be designed to deliver the same consistent volume of solder required for each joint.   Care must be taken, however, to place only one preform on a pin, and not miss any.  This is what makes InTEGRATED PREFORMS^® desirable.  The solder washer array is designed and manufactured to fit the pin configuration so only one washer goes on a pin.  If extra solder volume is required, InTEGRATED PREFORMS^® can be easily stacked.

With today's drive to optimize profits, InTEGRATED PREFORMS^® present an excellent opportunity.  The biggest advantage of InTEGRATED PREFORMS^® is the fact that quality can be improved while costs are reduced.  If you are looking for any easy way to cut costs, increase production, improve quality, improve customer satisfaction, and, ultimately, increase your profits, talk to me about InTEGRATED PREFORMS^®.

Paul Socha psocha@indium.com

BONUS: Read our white papers regarding InTEGRATED PREFORMS^® .

Attaining consistent and accurate solder (and flux) volume uniformity in hand soldering has long been a critical quality and performance issue.  Traditional hand soldering creates consistency and quality issues from operator to operator, from shift to shift, from day to day, and even within the same operator within the same day!

Hand soldering always delivers inconsistent solder volume.The human factor is a major contributor to this non-uniformity.

Solder preforms:

• offer a solution to the need for consistent solder volume.
• are the preferred solution in tens of thousands of applications where the uniformity of solder volume is critical.
• provide the correct alloy, the right size, and the exact volume of solder that you require.
• are available in custom sizes, shapes, volumes, and packaging, to suit your production needs.
• can be flux coated with a consistent and precise volume, and type, of flux. Flux-coated solder preforms reduce process time by eliminating a separate flux application step. They can also reduce total flux usage.
• can be ganged together (InTEGRATED^® Solder Preforms) for mass placement. I blog about that here and here.
• can be manufactured using a fugitive dye (in the flux coating) imparting a visible color for easy identification. This helps distinguish visibly-similar but different (alloy, dimensions, etc.) solder preforms.
• can be clad to a dissimilar metal, providing extra strength and/or the ability to bridge gaps.

Using,  applying, positioning, and reflowing solder preforms (and flux) is simple. Simply place the solder preform at the joint site (by hand or robotically), and apply heat.  It’s really that simple.  Each joint will have precisely the same solder volume regardless of who is doing the soldering.

Manage your 1st-pass yields, your quality, your field failure rates, your customer satisfaction, and your profitability by putting solder preforms to work for you.

Paul Socha

23 October 2012

During a NanoBond^® reaction, assembly pressure may determine if you create a quality solder joint. There are many details that can influence how much pressure is actually needed:

• NanoFoil^® thickness
• Solder type/oxidation/thickness
• Surface roughness
• Part flatness

   

In practice, we use anywhere from a few psi (like the clips shown above) ...

... up to 400-500psi (with a press, as shown below) – depending on the criteria listed above.

The main thing to keep in mind is that you want uniform pressure across your interface.

As illustrated in the pressure paper images below, uniform pressure across a NanoBond^® interface is critical for maximum bond strength.

We will discuss this further in "Aligning the Assembly".

*This post is part of the NanoBond^® Process series

While on a recent trip to Malaysia, I interviewed two colleagues regarding trends in semiconductor assembly. My previously-published interview with Sze-Pei Lim appears here.

This time, while on a visit to a logic device manufacturer in the North West, I [ACM] talked briefly to Sehar Samiappan [SS], Indium Corporation's Area Technical Manager, about our recently-developed water-soluble pin-transfer Ball-Attach Flux, WS446-NRD, which is designed for BGA applications of 0.5mm pitch, and greater than 1500  I/Os.

[ACM] What is the origin of WS446-NRD?

[SS] The development was driven by a customer need for a guaranteed good quality BGA (ball-grid array) solder joint, but with reduced environmental impact. Our very quality-focused customer uses several different suppliers of organic FC-BGA substrates with copper OSP pads. The customer had serious concerns about occasional poor solderability of SAC305 solder spheres onto substrates. The key defect seen was poor wetting onto the OSP-coated copper pad, which would give rise to variability in both joint strength and bump coplanarity,  and even (in worse cases) missing-ball / “big ball” effects. Some of the pad finishes were seen to be highly oxidized, severely restricting solder wetting during reflow. Variability in the surface finish was found to be not just from supplier to supplier, but also showed up as lot-to-lot variability from lower cost suppliers.

Some of the differences seen could be attributed to the method of mask desmear from the C4 “cage” of the flip-chip (top side) area, which was either a plasma-based desmear or an oxidizing inorganic acid dip, that was clearly having effects on solderability of the opposite (bottom) BGA side of the substrate.

[ACM] What steps have customers previously taken to get around this issue?

[SS] This is a serious issue for many ball-attach flux users, and some customers have gone to the lengths of using a special fluxing step to remove contaminants such as oxide and OSP (organic solderability protectant) coatings. These liquid fluxes are very reactive, but require  separate spraying, reflow, and cleaning stages that add cost and time. The halogenated ball-attach fluxes of the WS446 series have an established good chemistry that allows wetting of SAC105, 305, and 405 onto a variety of metallizations. In the semiconductor assembly industry, the WS446 fluxes are well-known in Taiwan, and throughout South East Asia, for their good solderability and long pot-life in a variety of FC-BGA applications.

[ACM] What was different about WS446-NRD, and why was it developed?

[SS] WS446 fluxes are all colored, using a bright red dye, so the flux can be seen by eye and automatically detected by vision systems. Red coloration also allows automated ball-attach flux dipping replenishment systems to detect flux levels. Normally, colored fluxes are not a problem, but the customer had some environmental concerns with the red color contaminating the water-wash equipment, and building up in their water-recycling system. WS446-NRD was developed from the basic WS446 flux series chemistry, but  without the red dye. The solderability performance of WS446-NRD was excellent, eliminating the variations in OSP solderability without requiring any additional processing steps. WS446-NRD also passed internal process and product requirements, such as cleanability, and the customer was very pleased with Indium’s ability to rapidly tailor a chemistry to their specific requirements.

[ACM] Sehar: thank you. I look forward to sharing a durian with you again when they are back in season.

Ultrasonic Testing (UT), performed by acoustic microscopy, is a great way to determine the quality of a solder bond without destroying the assembly.

As a very basic description, SAM (scanning acoustic microscopy) uses sound waves to travel through the assembly, much like some animals use sonar to locate objects. Sound waves generated by a transducer travel through the assembly and bounce back when they encounter different materials. Air reflects back much differently than metal, so, by using sound waves, we can locate pockets of air (voids).

In a NanoBond^® you can expect to see 2 things:

1) darker spots where the NanoFoil^® is located in the bond and

2) very little voiding, which will appear as white areas. Here is an example of voiding:

Most of the time we see little or no voiding. We typically achieve <2% when we bond sputtering targets with NanoFoil^® in-house. Here is an example:

If you have experience with traditional large area soldering methods, you will notice that <2% voiding is a sign of a very good bond.

For sputtering targets this is necessary to reduce pump-down times and eliminate ‘virtual leaks’. Contact us if you are interested in learning more.

*This post is part of the NanoBond^® Process series

About a month ago I posted about the various 3D technologies (chip creation, packaging and printed circuit boards) that are being used to optimize the various electronics upon which we all rely.  Molded Interconnect Device (MID) technology has been around for more than 20 years and is being used extensively in cell phone antennae. 

Recently I discussed the state of the art of 3D-MID technology with the Director of 3D MID Technology at Cicor in Switzerland, Nouhad Bachnak.  Cicor is one of the key players in the development of molded interconnect devices.

Carol: MID technology has been around for more than 20 years but, so far, it is only widely adopted in cell phone antennae.  What is sparking the renewed interest for other electronic applications?

Nouhad: The idea to use 3D-MID for electronic applications is much older than the idea to use this technology for antenna applications.  When this technology started in the 1980's there was a high euphoria that it would replace the printed circuit board (PCB).  But there was a lack of qualified materials and a lack of specific know-how for the manufacturing process.

Over the last few years a tremendous amount of development work has been done and considerable progress was made.

New MID-specific design, chemical and 3D assembly machines were developed and successfully implemented in serial production.  Millions of antennae have been produced, but also several other products like sensors, switches and LED carriers for automotive, medical and industrial applications show the benefits of 3D-MID and this encouraged customers to use them.

Carol: What processes do you offer for making these devices and what are the benefits of each?

Nouhad: We use the LPKF Laser Direct Structuring (LDS) and the 2S (two shot molding) processes.  These two processes have to be seen as complementary to each other, rather than competing with each other.

Major advantages of the LDS process are:

• Simple injection molding tool
• Easy layout changes (just by changing the CAD layout)
• Thin structures are possible 150 µm or even smaller

Major advantages of the 2S process are:

• Only two process steps for the substrate manufacturing (molding and plating)
• High reproducibility of the layouts
• Very economical for big plating surfaces and complex layouts

Carol: What are the biggest challenges facing component attachment to 3D-MID?

Nouhad: The first one is the 3D attachment of the components on the MID substrate.  Precise 3D electronic assembly systems with several axes and sophisticated optical systems are required to master this task accordingly.  In this area we are working with Haecker Automation, who develops such high-standing quality systems.  The other aspect is the capabilities of the substrates to withstand high temperature solder profiles.  There are of course several materials which can withstand up to 260C.  But these materials usually have some other weaknesses (fragile, too expensive).

Carol: What markets are showing the most interest in using this technology to replace traditional printed circuit boards?

Nouhad: Using the benefits of 3D-MID is not limited to certain markets.  3D-MID can be used everywhere, where plastics meets electronics and it is not just about replacing PCB.  3D-MID opens a tremendous amount of possibilities by using MID as an interconnectivity module combining electrical and mechanical functions in one part.

Carol: What do you see as the key drivers in moving MID forward in the electronics industry?

Nouhad: The key drivers in moving 3D-MID forward are:

• Miniaturization: due to space problems (automotive, medical, telecommunication, etc.)
• Rationalization and system simplification: reduction of process steps, number of parts and mounting time
• Functionality: new functions which are made possible only because of the high functional integration possibilities, design flexibility and the precision given by 3D-MID

The 3D-MID technology advantages in these areas are:

• Optimal three dimensional space utilization
• High function integration density of mechanical and electronic functions
• Saving of parts and process steps

Carol: Where do you see the industry in another ten years?

Nouhad: This is the most difficult question!  In this context I would like to quote the famous physicist Nils Bohr: "Forecasts are always difficult-especially if they concern the future".

Nevertheless one thing seems to be evident: the 3D-MID technology has already gained a footing in the market and is growing very fast.  For our part, for the next three years, Cicor is planning its manufacturing capacities according to growth rate expectation of more than 50% per year.

Thanks Nouhad for your time and expertise. 

Like we have often said about indium metal, the possibilities are endless®!

Carol Gowans

Folks,

The impetus for writing the Patty and the Professor series, in 2009,  <posts here>  <hardcopy book here> came from my observations that many assemblers were not very focused on productivity.  Productivity seemed to be an afterthought.  Since then little has changed.  This conclusion seems astounding, since all assemblers are in business to make a profit.

In light of this situation, I have developed 10 questions, valued at 10 points each, to help assemblers assess their profitability potential. If You are a printed circuit board assembler, take this quiz and see how you rate:

1. Although quality may be job 1, our company has a strong focus on productivity. At all levels everyone understands that, when the line is down, we are not making money.
2. We have a practice, understood by all, that if a line is down more than a specified amount of amount time, the line down situation is escalated through the management chain.
3. All of our operators, technicians, and engineers have been trained in procedures to assure the minimum amount of downtime.
4. We measure and graph our line uptime and other productivity metrics.  Everyone knows the approximate value of these metrics.
5. Our component placement machines are time balanced.
6. We use feeder racks and other preparation devices to prepare for the next job while the current job(s) are running.
7. A major consideration in the purchase of our assembly equipment is its effect on productivity, not the equipment’s cost alone.
8. A major consideration in the purchase of our assembly materials, such as solder paste, is its effect on productivity (e.g. poor paste response to pause would be a strong rejection criteria,) not the material’s cost alone.
9. We us productivity and cost metrics, such as non-material assembly per I/O assembled (NMAC/I/O), to track our performance.
10. We understand that sometimes an added expense, such as solder preforms, can actually reduce the total cost and increase productivity and profitability.

Ratings:

• World Class: ≥ 90
• Above Average: 75 - 89
• Average:  55 - 74
• Below Average: < 55

How did you do?  Let me know what you think. We hope to have this online soon.

Cheers,

Dr. Ron

PS:  Here is my golf score in a recent one man scramble. I was hoping to break 60 and it worked out.

I recently had a chance to catch up with a friend and colleague, Jasbir Bath. If you’ve spent time in the electronics assembly industry you have most likely met him, heard of him, or used an industry standard that he has helped create. Jasbir is a founding member of The Solar Engineering & Manufacturing Association,  SEMA. Who better to talk to about a new association than a founding member?

Jim: The Solar Engineering and Manufacturing Association (SEMA) is a relatively new association for engineers in the solar industry. Can you tell me a little about why it was created?

Jasbir: It was created about 2 years ago based on a need by the solar engineering/manufacturing base to address issues in the industry. There are many organizations in the solar industry but none are wholly dedicated to the engineering/manufacturing profession. SEMA was formed to address this need. We are working to address a number of gaps in the industry highlighted by the SEMA membership which include Education, Training, Standards, Reliability, Cost Reduction and Technology Gaps.

SEMA is a group of engineers, manufacturers and related professionals in the solar manufacturing and related disciplines who volunteer to conduct activities in the organization. The projects/programs we work on are driven by the active involvement of the membership.

Further details on SEMA and what we do can be found on the SEMA website at www.solar-ema.org

Our membership costs are low as we are not an organization looking to make a profit but to encourage participation and work to advance the solar industry as well as advancing education, training and collaboration within the solar manufacturing industries.

Jim: I heard there’s a new solar conference coming up? Can you tell me what makes this one different than all the other solar conferences we go to throughout the year?

Jasbir:  SEMA is collaborating with SMTA (Surface Mount Technology Association) to develop a conference meant for engineers and managers in the field to look at the areas of concern in the industry and develop ways to address them. We don’t see a similar conference to this which covers such a broad range of subjects which is specifically focused to address the needs of the industry. The program will consist of presentations and discussion covering the reliability testing of PV Modules covering gaps and where future work needs to be done. It will highlight various reliability programs being done in the industry with an assessment of current and evolving standards in manufacturing and reliability.

We are pleased to have a great line up of speakers and presentations. SEMA will present its reliability report assessing the reliability of PV modules at the conference. We will also have speakers from UL, IPC and NREL to discuss international solar standards together with a discussion of the work of the PV QA Task Force forum from leaders in that Task Force group. Areas covered will include temperature, humidity, voltage, mechanical and UV testing of PV modules and diode testing.

We will also have presentations on the reliability of microinverters/inverters and future trends from organizations including Sandia. PV Manufacturing Issues will be discussed by companies including Flextronics. The Global Solar Outlook will be reviewed by companies including Navigant, Custer Consulting and Prismark. Finally we will review general PV Module hazardous issues such as Electrical and Fire Concerns and well as Module Warranty/ Traceability Issues.

In addition we have industry leading training courses at the event on PV Module Manufacturing and Troubleshooting and PV Standards in addition to exhibitions.

The SEMA/SMTA Conference, Training Courses and Exhibition are from March 21^st to 23^rd at the Fairmont Hotel in San Jose. Further details on the program and sign up can be found at http://www.smta.org/solar/

Jim: One more question for you Jasbir. I know from working with you in different associations, that you are personally invested and involved in the future of module assembly. What attracted you to this field, and what keeps you interested in it?

Jasbir: I have been involved previously in the electronics manufacturing industry during the transition from tin-lead to lead-free soldering due to environmental legislation requirements. This was a challenge being involved in both from a technical and logistics perspective, but it was also fun as you saw the rewards of your efforts when the transition occurred successfully.

The solar/PV industry has challenges in addressing how to produce good quality and reliable products at lower cost, and it gives me the opportunity to try to make a positive contribution in an evolving expanding industry.

Jasbir and I look forward to seeing you in San Jose!

~Jim

Two categories of solder are available to choose from when the in-service environment for a device reaches above 125°C either in continuous operation or thermal cycling accelerated life testing. These categories are those comprised primarily of lead, and those of gold. From the electronics industry’s drive to eliminate lead, many manufacturers who have traditionally used lead solders are treading cautiously, looking now at the gold solders, primarily at Indalloy 182 (80Au20Sn).

The most common concern regarding this switch relates to the strength of AuSn, which is much higher than the lead solders. The degree that this should be of concern however, should be realized within the scope of the application.

For instance, review this case scenario:

Indalloy 159 (90Pb10Sn) was used in a device for years to adhere high temperature sensors to a calibration probe that is slowly cycled in operation from 350K (~75°C) to 500K (~225°C). The solder joins a nickel and gold plated Kovar™, or platinum or platinum coated, nickel lead to a tinned copper lead. The solder joint is not placed under tension or shocked.

Considering the high temperature solder options in this scenario, the AuSn would be mechanically preferred.

Why?

Well, tin-bearing soft solders will leach gold from gold metallizations during soldering, creating a brittle Au-Sn intermetallic layer within the solder joint. The more gold available, the more consumed, and the greater the thickness of the resultant intermetallic layer. The brittle nature of this layer, situated intimately next to the relatively soft PbSn solder layer, creates differential stresses that promote crack propagation upon thermal cycling.

AuSn was not considered previously because the engineers were familiar with its hardness and, given the cracking failure described using a softer solder, they did not anticipate improvement. It was a pleasant surprise to them to find that switching to a lead-free solder would not sacrifice the quality of their device. AuSn is a brittle alloy but, unlike the description above, no differential stresses are involved. 

Note: Eutectic gold solders have been used for many years to solder nickel plated Kovar™ lids to high reliability ceramic packages and have a good history of fatigue performance.

Folks,

I have often pointed out that SAC solder's poor wetting is both a curse and Godsend.  It is a curse when trying to fill a through-hole in wave soldering, and a Godsend when assembling close lead spacings as shown in the image (below). Indium Corporation colleague and friend, Mike Fenner (image below), pointed out that, when I say that, "SAC solder doesn't wet well", I should be saying, "it doesn't spread well". His explanation follows:

SAC is different from SN63, and I think it is helpful to explain the difference by making a subtle differentiation between wetting and spreading.

The way that solders spread and wet to a surface is a balance of competing forces. We have surface tension acting to make the molten solder shrink into a ball, and wetting forces trying to make it spread across the surface. Wetting is also the action of the solder dissolving into the surface to form an intermetallic. This intermetallic is essence of the solder joint. The balance changes with different alloys, surfaces, and processes.

Most people are very familiar with the way that tin lead solders behave - and that governs their expectations. The different balance in SAC means the solder tends to spread less for the same wetting and, therefore, can give the impression of a lower quality joint. This lack of spread is usually expressed as 'poor wetting'.

I would explain this by saying the “active ingredient” in both solder families is tin. SAC alloys have a ~50% higher concentration of tin than the Sn63 solder alloy. This gives them a higher surface tension which increases the balling (coalescing) force. At the same time, the less dilute tin, in SAC solders, dissolves into a surface faster. So the final SAC joint can have a well formed intermetallic, but not high spread. These relationships will vary with surface finish and, of course, flux chemistry and process conditions come into play, but that’s for another day. Meanwhile I hope this simplified explanation helps.

Thanks Mike!

Cheers,

Dr Ron

The solder image is courtesy of Vahid Goudarzi of Motorola.

At the time of writing, the price of silver (Ag) was approaching the USD$50/tr.oz. (Troy ounce) level, and threatening to go higher. With 1 Troy ounce being 31.1grams, this makes the cost of pure silver ingot close to USD$1.60/gram.

Image from goldsilveroz.com

Materials costs are therefore a major consideration for anyone using silver in any form. Naturally, we are now seeing a few Power Semiconductor packaging houses evaluating the possibility of moving away from silver-filled epoxies for die-attach. The alternatives they are considering include the adoption of solder paste (or solder in some other form: wire / ribbon / preforms) versus a silver-filled epoxy.

Here are some thoughts on the Power Semiconductor assembly pros and cons, based on using solder paste as an alternative to silver-filled epoxies.

Good news (+)

+   Reduced materials costs
+   Improved pot-life / shelf-life *
+   Improved high temperature thermal-cycling
+   Strong, metallurgical joint formed between leadframe (substrate) / joining material / die
+   Improved thermal conductivity
+   Faster throughput (more units per hour, UPH)**
+   Easy clean-up ***
+   Does not wick onto NiPd surface to cause poor wire bondability

 * Although it is true that solder pastes are stored under refrigerated conditions, they do not require the -40C storage that is typical of silver-filled epoxies. 

 ** The dispense of solder paste is very rapid and can be done using multi-dot dispense heads. It undergoes rapid temperature reflow, versus the slow cure needed for metal-filled epoxies, which can be up to typically 1-3 hours, depending on the volume of silver epoxy.

 *** Because the solder paste flux does not cure like a polymeric material,  tubing and other conduits for the solder paste are easily cleaned out using common solvents, or can be simply purged with flux.


  ==================

Bad news (-)

-   Capital costs #
-   Adoption time / new process learning ##
-   Needs a solderable die surface
-   Voiding increase ####

 # The main cost-drivers here are:

- Reflow: Specialty reflow equipment is required for high temperature solders, such as
Heller or BTU reflow ovens

- Cleaning: If wirebonding is required after the reflow process, standard cleaning equipment and cleaning chemistry (aqueous or solvent-based) will be needed to remove flux residues

- Gas: Forming gas (H2/N2) or simple nitrogen may be needed to assist reflow.

Note that increasingly, for clip-bonding (non-wirebonding) applications using the new ultralow residue solder paste Indium9.32, even cleaning may not be needed, as the residue has been found to be compatible with compatible with a number of molding compounds in the industry.

 ## By partnering with a company like Indium Corporation with many years of experience in die-attach soldering, the ramp-up time can be significantly reduced.

 ### A solderable surface is usually a sequence of Ti / Ni / (Ag or Au) plated layers. The thickness of the silver (Ag) or gold (Au) precious metal layer is usually limited to 100nm (0.1microns). Compare this to a standard silver-epoxy bond line thickness (BLT) of 0.5-2mils (12-50microns).

 #### Acceptable voiding of less than 5% of the total die area is fairly easily achieved with good quality substrates and die-finishes.

  ==================

In closing, I am indebted to my friend and colleague Sehar Samiappan (Indium Corporation Area Technical Manager - South East Asia) for his insights.

Contact me to discuss this further.

Cheers!   Andy

我自己是一个电子焊接材料销售人员，虽然是B2B，但是生活中当我评估B2C的销售人员时，也常常想到自己的客户们……最近我们想把花园里的一棵斜树砍了，朋友介绍了他曾经用过的4家公司。于是我逐一联系比较。

第一家：没人接电话，留言了也一直没有回复。---客户服务不及时，比较差，不考虑了。

第二家： 一个老头接了电话，我们约好了时间来看树。老头准时出现在我家门口，整齐的穿着，礼貌亲善的销售，职业的打招呼和握手。看了树，问了我的需求后，他用专业的纸条写下了情况和报价，并详细解释了我对砍树的一些问题：几个人来砍，时间多长，有多复杂等。 此外，他还适当“销售”了一下自己和自己的公司： 经验丰富，口碑好等。最后，老头留下了自己公司的保险和营业执照等信息，就礼貌职业地握手离开了。--- 这一家总体感觉不错；但是我不知道他的价位是否合理，再比比看。

第三家：没人接电话，于是留言了；第二天一个年轻人回复了并来看树了。礼貌职业的握手，但是全身十分肮脏的穿着（或许他刚给别人砍完树吧）。年轻人看了树后，报价了；价格区间和第二家老头的不相上下。但是当我问到砍树的一些细节时，他的回答和老头的回答有比较大的差别（这些差别让我感到他是故意在显得自己的报价已经是相当的实惠了）。后来我说我会考虑的，因为我还在货比三家，年轻人显得有点点急了，说他可以明天就来完工，还问我找了哪几家…..最后他还是职业礼貌地离开了；没有留下报价单或是其他信息。---总体感觉一般；虽然待客户比较职业，但是少了老头那种特别专业和比较从容、真诚做生意的感觉。价格区间既然和老头那家差不多，就应该是这个范围了。

第四家---电话约好了时间，但是一个中年人提早了1个半小时就来敲门了，说他自己在同一时间被安排2个客户，所以只能提早到我这里（但是为什么没有任何提前通知呢？万一我不在家呢？）。没有因为提前的抱歉，没有职业的招呼。他看完树后，表现出很难办的感觉，并开了一个天价。 我说再想想吧，那个中年人居然什么都没有说，头也不回地甩门就走…… --- 看来是没有最差，只有更差啊！

我录用了第二家老头的砍树公司。联想一下自己平时做电子焊接材料(Electronic Solder)销售，代表的不仅仅是个人，更是整个公司在客户面前的形象，我自己做到以下这些基本的要求了吗？

---能否完成这项工作。我联系的这四家公司是朋友曾经用过并推荐的，起码都完成过砍树工作。 如果换成是Indium的产品，那么就是我们产品的质量好坏(Product Quality)，以及产品质量的稳定性(Product Quality Consistence)。这对客户们的产率(Yield Rate)和不良率(Defect Rate) 都有很大的影响。而我作为销售，对自己公司的产品了解吗？有信心吗？这些，都会在和客户交流的过程中潜移默化地表现出来的。

---基本的销售要求 (Basic Sales Requirement): 认真准备，准时，有礼貌，打招呼，整齐的穿着等。

---销售的技巧(Sales Skills): 是否了解客户的真正需求而有针对性的销售；是否有销售的工具协助；是否会“过犹不及”或是没有给客户全面的有用的信息等。(Goal Oriented---Begin With The End!)

---客户服务和支持(Customer Service & Support): 及时准确地给客户信息回馈和支持。

---其他：价格，客户关系和客户关系的维系（特别是对于B2B的客户来说），公司的形象、口碑和声誉等等……  

时常对照反省，自勉之。

Cheers!

Pic:Google Image

Jon major recently joined the Indium Corporation as a Product Manager for Solar back-end assembly products. I greeted him with this impromptu interview.

Jim: First of all Jon, welcome. It’s great to have you as a new addition to the team!

Jon: Thank you Jim – it’s an exciting time to be at Indium Corporation and a fantastic time to be a part of the growing solar industry. I am extremely enthusiastic about my new position and am looking forward to making a positive contribution to the solar industry.

Jim: I noticed it didn’t take you long to get up to speed. Your time in Silicon Valley must have helped.

Jon: Coming from the electronics industry with a focus on product development, new product introduction, manufacturing, and external partner management, I am excited that my past experiences can contribute both to the industry and to Indium Corporation. After joining Indium only a few weeks ago, not only am I getting used to Upstate NY weather, but I have been immersing myself in solar with the goal of gaining a comprehensive understanding of:

•       Both rigid and thin-film technologies

•       Technology trends

•       Global and regional markets (EU, China, US, North America)

•       Solar supply chain (Silicon, wafers, cells, module, equipment, inverters, integrators)

•       Equipment manufacturers, contract manufacturers, and how we can collaborate with them to move the industry forward

•       Our products and pricing

•       Our current and future customers

•       Our short and long term opportunities

•       Our competition

•       Our roadmap

•       Our strengths, weaknesses, and threats

•       Our manufacturing capabilities and our QA process

•       Our sales channels, value proposition, key differentiators

•       All Indium processes

Jim: I know you've got solar products on your mind. Let our readers know a little bit more about your role here at Indium?

Jon: As a Solar Backend Product Manager I will focus (officially) on the business development and growth of Indium’s Solar Back End product offerings.  Now that sounds great but what does it actually mean? I could cut and paste my official job description but I prefer to explain it in my own words. As I think about the first part of that statement, “business development and growth…”, I see my role as:

–      Know the market, the customers, the product, and the competition

–      Develop relationships with the Indium team, reps, partners, equipment manufacturers, and, of course, customers

–      Write valuable data sheets, publications, and sales literature

–      Listen to our customers' needs and provide solutions

–      Manage schedules and orders with minimal surprises

–      Build cross-functional collaboration (sales, distribution, marketing, engineering, R&D, QA, production, management)

–      Never let down partners or customers

–      Support all functions of the organization, both internal and external

–      Deliver above & beyond commitments

–      Make great bets – on technology, customers, and opportunities

–      Understand the product life-cycle

–      Ship high quality, consistent product

The second part of that statement “..of Indium’s Solar Back End product offerings” is fairly straightforward. Of course this means I will focus on Indium’s current back end products (tabbing ribbon, bus ribbon, metallization paste (or as I prefer to call it – “grid ink”), flux and flux cored wire). With a product development background, this also means I have an opportunity to work with customers, partners, and R&D to develop and bring new products to market that will advance the module assembly industry – very exciting for me personally.

Ultimately, I think of my role as both building awareness of Indium’s products and superior technical support available to our customers as well as helping to shape our growing industry.

Jim: Okay Jon, you’ve had a while to settle in and get familiar with our Solar Team’s past and present – what are you planning for the future of module assembly?

Jon: Regarding the future of module assembly it’s a bit early to know for sure but I am excited about our low-temperature bismuth-containing alloys. These low temperature, lead-free, bismuth-containing alloys reduce the soldering process temperatures, thus reducing thermal stresses. I’m also working with the Indium production team to further reduce our tabbing and bus ribbon yield strength. A lower yield strength will reduce mechanical stress on cells during the assembly process. This is crucial to minimizing the possibility of microcracks and cell breakage during the solar module assembly process.

In closing, having lived in California for the last 10 years, I am not 100% familiar with our Upstate New York climate, and especially not all the snow shoveling. I see in my future a solar powered driveway heater!

Jon can be reached at jmajor@indium.com

Although most scientists today feel that alchemy has been widely discredited, and I have been taught to agree, the idea of it is whimsical and exhilarating.  Of course, I don’t have a hope of changing the makeup of bismuth or transforming it into another metal, but in a modern way, it’s very interesting how bismuth can be used to change the properties of other metals significantly - through alloying. In my last post on bismuth, I outlined its physical properties, some of which I find rather unusual. The main reason I originally researched bismuth was because of its viability for use as a low temperature Pb-free alloy.

BACKGROUND:
I'm not an alchemist like Newton, I can't transmute bismuth to gold like Seaborg, but I can use bismuth and metallurgy to transform an alloy.

I just read a fascinating article about Sir Isaac Newton titled, “Moonlighting as a Conjurer of Chemicals”. Newton is widely regarded as one of the most important people in the history of science, and he was very devoted to his work. The revelation in this article about the depth of his interest in alchemy left me somewhat awestruck. In my previous reading about Newton, I remember perhaps a mention of his interest in alchemy, but I guess I figured it was because science and alchemy, at that time, were fairly closely related. As scholars are starting to translate more of his diaries, they are discovering that his passion was alchemy and he saw it as the path to complete control over the natural world.  

I suppose if it was still socially acceptable to be an alchemist that is what I would have wanted to be; it just never seemed to be a viable option. What I have chosen to do now kind of makes sense considering chemistry/metallurgy is about as close as you can get nowadays. 

Reading this article reminded me of some interesting information I had come across while researching bismuth a couple months ago; namely that, although bismuth wasn’t one of the seven central metals in alchemy, it has an "alchemical" symbol (#52 in the image to the left) and was frequently used, although it’s not known for what purpose. I also came across this bit of information:

“In 1980, a scientist named Glenn T. Seaborg was able to transmute a minute quantity of bismuth into gold at the Lawrence Berkeley Laboratory, via nuclear collisions.” 

Seaborg is a fascinating scientist in his own right and discussion about him could fill quite a number of blog posts. Is it possible that alchemists underestimated bismuth and should have focused more on turning it into gold?

BACK TO MODERN TECHNOLOGY:
The eutectic alloy of 58Bi/42Sn has been used since the Pb-free transition as a low temperature (138°C liquidus) option for soldering products used at ambient temperatures - such as consumer electronics.  Note the low melting temperature of this alloy, despite the individual melting temperatures of bismuth and tin, 271°C and 232°C, respectively. Although bismuth is typically known to be quite brittle, this alloy has been shown to perform similarly to the SnPb eutectic solder (in response to a comment on my last post, for further data-based information, please feel free to contact me directly). In cases where more ductility is desirable, 1% silver can be added, further improving thermal shock and fatigue resistance. Perhaps the similarity in performance makes sense because of bismuth’s proximity (right next to) lead on the periodic table, although they differ in several other qualities such as toxicity.

The more I learn about bismuth, the more interested I become. Now if only I could find some in-depth alchemical information about it from Sir Isaac Newton.

I was reading a blog post (click here to read it) authored by the owner of Taylor Guitars, and I started relating it to how I feel about solder. For those of you that don’t know, Taylor guitars are beautifully crafted instruments, not the kind of “dime-a-dozen” toys that you find at garage sales or music sections of department stores – they are the real-deal. Last year I happened upon a tour

of the Taylor Guitar facility in El Cajon, CA after a trade show and I was blown away by how much care goes into each of the guitars that are produced there. Taylor’s core customers realize how special the product is, and they will settle for nothing less.

So, how the heck does this relate to solder? As a tech guy I get calls from people who want Indium Corporation material - they don’t know which product they need yet, but they want to use our products if at all possible. It might be because they feel good about the quality, packaging, technical support, supporting documentation, or just because they feel like they have a connection with us. To me, that’s awesome! I admit - I am the same way with some things I purchase. Feel free to give us a call, even if it’s just to chat!