Indium Corporation Blogs

Why do we care so much about target bonding? This is important because a sputtering target that truly performs will allow greater process flexibility, and higher throughput. An introduction from Eliminating Bond Stresses of Sputtering Targets at Operating Temperatures:

“…It was observed that bonding with reactive multi-layer foil as a localized heat source allows use of higher temperature solders for joining target and backing plates for sputtering. This permits the use of higher power densities and higher operational temperatures, since the bond is generally the first part of the target assembly to fail at higher temperatures.

After learning that a condition of low stress can be set at ambient temperatures, it is a logical next step to explore setting a low stress point at other temperatures. If the theory is true, that a zero stress point could be set at operational temperature, then a sputtering target would be able to operate with no stress imparted by thermal expansion. This would allow higher sputtering power densities, which would result in an increase of throughput.”

Whenever two materials with different coefficient of thermal expansion values are bonded together, they will expand and contract as the temperature changes.

Assuming these two materials are bonded rigidly, there are two things that can happen as the temperature changes: 1) the bond will break apart or 2) the assembly will bend to accommodate the stresses. Either of these outcomes can be disastrous for a sputtering target. The important thing to realize is that this is a function of temperature change. Limit the temperature change and you will reduce the effects of CTE (Coefficient of Thermal Expansion) mismatch.

The answer to this is found in the conclusion of Eliminating Bond Stresses of Sputtering Targets at Operating Temperatures:

“Reactive multilayer foils can be used to form a low stress bond at room temperatures. This is especially important for sputtering target assembly. The same bonding process can also be performed at elevated temperatures for a zero stress point at or near operational temperatures. With a firmly bonded bi-metallic assembly, curvature over a large temperature range cannot be ignored, but the effects of this can be mitigated through selectively setting a zero stress point at a strategic temperature.”

Fluxes are an interesting element of working with many solder applications. With so many specialized fluxes there is usually a perfectly-tailored flux for removing oxides from any solderable surface. Even though we love fluxes at Indium Corporation – not all of our customers share that same affection.

It is understandable; some applications cannot tolerate flux contamination. If a customer chooses to say goodbye to flux we still have a few tricks to form a solder bond without that formulation of organic acids and solvents with which we are so familiar. One of those tricks is to use NanoFoil^® to bond the two parts. For a comprehensive background of the process, click here.

Folks,

Many agree that the greatest technical achievement of human kind was landing a man on the moon and returning him safely to earth. (Just think about the fact that all of this was done with less computing power than your smartphone!).  Some of the folks involved in this effort  joined together to form The Right Climate Stuff research team.

For the past several years they studied the evidence for anthropogenic (human caused) global warming (AGW).  Less than a month ago they published their report.  I encourage everyone interested in this important topic to read their report. The team’s skepticism for AGW matches my own, point for point.   Their summary of their report follows:

• “Carbon-based AGW science is not settled. This refers only to the Carbon or CO2 role in induced warming
• Natural processes dominate climate change (although many are poorly understood).
• Non-carbon-based AGW anthropogenic forcings are significant. These include land use change, Urban Heat Island (UHI) effect, black carbon, and aerosols.
• Carbon-based AGW impact appears to be muted. Other sources are not necessarily muted; the impacts of changing solar activity, El Nino/La Nina-southern oscillation (ENSO), Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), black carbon, etc., are observable.
• Empirical evidence for carbon-based AGW does not support catastrophe.
• The threat of net harmful total global warming, if any, is not immediate and thus does not require swift corrective action.
• The US government is over-reacting to concerns about anthropogenic global warming.”

Cheers,

Dr. Ron

Image source: Right Climate Stuff Home Page

In an earlier post I mentioned one of the presentations we gave at the 2013 SVC TechCon. The other presentation that our team delivered at the show (presented by Jacques Mateau) regarded another very interesting topic. The paper, High Temperature, Pb-Free, Metallic Sputtering Target Bonding Using Reactive Multilayer Foil, deals with creating high temperature NanoBonds®:

“Metallic bonds provide excellent thermal and electrical conductivity, but are limited by the relatively low melting point of the solder material used, 157°C for indium or 217°C for tin-based alloys. This limits the power input, which in turn limits sputtering rates and final film properties. There is a desire for a higher temperature (>300°C) metallic bonding process that can produce flat, stress-free target assemblies, enabling targets to run at higher temperatures for longer periods of time. We will demonstrate a metallic bonding process using reactive multilayer foils and a high temperature alloy with melting temperatures as high 380°C. We will compare this with traditional Sn-based solders typically used, specifically comparing shear strengths, void analysis, and cross sectional analysis.”

The image shown here is a bond formed with a 98Zn/2Al alloy and 60μm thick NanoFoil^®. You can follow the link above to read to paper, and email me if you have any questions or are interested in this process for bonding your sputtering targets.

~Jim

A visitor at our booth during the 2013 SVC (Society of Vacuum Coaters) conference suggested this video. In the video, a piece of indium is rubbed against a piece of gallium. The result is the formation of a room temperature alloy (75.5%Ga/24.5%In, mp: 15.7°C).

One of the fun parts of my job is talking with the people I meet at tradeshows. You never know what you might be asked or what you might learn.

For anyone who couldn’t make it to the 2013 SVC, just email me at jhisert@indium.com and I can make sure you receive a copy of “Eliminating the Bond Stress of Sputtering Targets at Operating Temperatures”. This paper discusses alternative processes for bonding targets - alternative processes that demonstrate the unique capabilities of NanoFoil^® and open your mind to currently undiscovered methods.

Interested? Let me know!

As business to business marketers, we've got a fancy label, "B2B". With that, comes an inclination, for some, to think that it's all about business. It isn't.

It's always all about PEOPLE. The consumers. The HUMANS!

Here's an example, from my personal life, of a business person who misses the point entirely (company name obscured):

"Thanks for contacting NNNNN support... regarding ordering boom arms from us. Sorry to say we don't sell finished good items. We only sell to dealer and distributors. Regards,"

You can imagine the sense of allegiance that was cultivated in my little consumer heart. "Regards"???

As a consumer, I would have appreciated a little background, perhaps some insight into WHY, and, of course, a list of local and online dealers for me to approach. Nope. None of that. Just a concrete-cold slap in the face.

There's ALWAYS a C in B2B.

An unfortunate misconception about nanotechnology is that it needs to be cutting-edge technology. This is most likely a manufactured perception, created by all the people out there trying to sell nanotechnology as the “next big thing”. While there are huge advancements in various industries being made due to nanotechnology, the use of these materials overall is nothing new. Keep in mind that, by the broadest definition, nanotechnology simply deals with materials with features <100µm in measurement.

NanoFoil^® is classified as a nanotechnology due to the thickness of each aluminum and nickel layer, however NanoFoil^® is a very simple material. It is interesting, useful …maybe even amazing. But regardless, it is simply Ni and Al foil. To make a point of how simple this is, let’s look at a common item I’m sure you have seen before: a metallized potato chip bag. The metal layer on these bags range from 40-50 µm thick, which is approximately the thickness of each bi-layer of NanoFoil^®. While this product would be considered nanotechnology, it doesn’t excite the average consumer. (This consumer was also NOT excited about how many chips were in this package when I opened it…)

Perhaps an easy way to sort out the high-tech nanotechnology applications is to distinguish anything that makes use of quantum physics effects of the nano scale materials? Or maybe we should categorize them based on how difficult they are to produce? In the end, nanotechnology does not always equal high-tech. I argue: why does it need to?

~Jim

In a somewhat recent post, I mentioned that my favorite NanoFoil^® application note was “NanoBond^® of Ceramic and Metal Sputtering Targets”. That document has some really useful data points for you. In addition, I’d like to mention another very interesting document: “NanoBond^® Thermal Interface”.

The really interesting part of this application note is that it is more of a case study of a particular thermal interface, which demonstrates the NanoBond^® procedure as well as the results. If you’re interested in how this compares to thermal greases and other TIM technologies, you’ll like the test data that is included.

Check out the full application note here.

~Jim

The development of SACM™ lead-free solder alloy by Indium Corporation’s R&D team was focused around improving the mechanical shock performance of low-Ag SAC (SnAgCu) alloys. We learned that the addition of Mn to create SACM™ also helps to improve the thermal cycling performance through refining the grain structure and slowing the intermetallic growth during aging.

The thermal cycling performance of SACM™ is superior to SAC305 after aging (see graph). 

To learn all of the performance attributes of SACM™, visit www.indium.com/SACM.

*This post is part of the Introducing SACM™ series.

上周有位客户朋友提到看我的公司博客，另外一位客户也因为我3年前写了一篇关于aQFN的博文而联系到我，让我倍感惭愧……上来除草了！看看自己2月份的记录，其实为自己准备了一堆题目，一个个来吧。先和大家分享一下Inidum 公司的新款有铅水洗焊锡膏Indium6.4！！

在美国，还有很大一部分市场是做defense (military) 和 aerospace，这些都还在用有铅水洗锡膏。Automobile 和 Industrial 也有相当一部分使用有铅水洗。所以有一定的市场份额。Indium根据目前客户们的需要，在以前的产品上加以改进，让Indium 6.4除了具有以前产品的所有特点外，还能突出在voiding方面的控制，尤其是大大减少QFN or LGA thermal pad的空洞。

Indium6.4的闪亮登场，让我的“小区内”在一个月之内拿到两个客户的新订单，还有好几个客户申请样品了：-）

Cheers!

Pic:

最近最让我感慨的是中国小将关天朗在美国高尔夫大师赛( Augusta Masters 2013) 上面的表现！！

“I’am Tianlang Guan. I’m 14 years old. I’m from China.” 大师赛有史以来最年轻的选手（而且还是以业余选手的身份参赛，非职业选手）！很难想象一位14岁的少年能在国际级大赛上表现得如此出色！他的从容，平静，专注，自信，甚至是深远，让他赢来了全世界的关注。我也找了一下Youtube上的录像，想知道为什么一位中国的少年能在这项中国不是强项的运动上取得如此成就。

后来发现，除去他父母在这项运动上对儿子的影响，关天朗从4岁开始就打高尔夫球了，而且是痴迷！他十年如一日的 “痴迷”，最终让14岁的自己一举成名！…… 《Outlier》一书上有一条“黄金定律”--- 10,000 hour rule 一万个小时。大概意思是说如果你想在某个方面成为专家，必须要专注地练习1万个小时或以上。我是赞同这条定律的；也觉得关天朗的例子是很好的诠释。

再想想自己在工作中哪一个具体的方面花过1万个小时了，好像真没有: 懂一些SMT，懂一些Semiconductor, 懂一点材料，懂一点技术，懂一点销售，懂一些marketing….. 呵呵，都是蜻蜓点水啊！

共勉之!

Pic: Google Image

As an application engineer working with various NanoFoil^® applications, I have learned which common items are very handy to have with me whenever I am working with NanoFoil^®. Leather gloves, tweezers, a glass cutter, metal strait edge / ruler, 9V battery, hydraulic or spring loaded press, high-temp tape, foam, and aluminum blocks are all used often. With the exception of the press, this equipment is all quite portable and inexpensive. There are good reasons for each item on the list:

• Leather gloves: Protect your hands when you must handle reactive foil.
• Eye protection: This should be fairly self-explanatory. Your eyes are important – keep them safe!
• Nitrile gloves: Used to keep finger oils away from bonding surfaces.
• Flat tweezers: Better than gloves for handling preforms and positioning parts.
• Glass cutter: Easily cut pieces of foil to size/shape.
• Metal straight edge / ruler: Used to guide the glass cutter for a straight cut.
• 9V battery: Can be used as a backup for activation of foil.
• Hydraulic or spring loaded press: Applies pressure during assembly and compensates for minute but important settling of the assembly.
• High-temp tape: Used to shield surfaces from excess solder or to position foil or parts.
• Foam and aluminum blocks: Distribute pressure evenly during assembly.

These items are all used on a daily basis here at the Indium Corporation, where we are the supplier and also one of the largest users of NanoFoil^® in the world.

One of our most demanding customers is ... the Indium Corporation! While we supply the world with NanoFoil^®, we also use a large amount for target bonding services. That’s right, we are one of our most demanding customers, using large amounts of reactive foil to turn slabs of materials into precision bonded sputtering targets for the semiconductor, solar, and other coating industries.

As a materials supplier, this bonding service is unique for us – but it has many advantages. One huge advantage is that is gives us hands-on experience with many unique bonding applications. Another benefit is that this allows us to observe NanoFoil^® from a customer’s point of view - for maximum quality control and performance feedback.

I know I’ve probably made it sound like we use all the foil for ourselves, but I assure you we have enough for your NanoBond^® process too. In fact, we already have a kit on the shelves waiting for you!

Because of the volatility of the metals market, the price of traditional SAC solders has been somewhat unpredictable. The chart below plots the price of SAC305 metal from June 2009 to June 2012.

Traditionally, solder is selected based on whether it meets the temperature and reliability requirements.  As a result of recent price volatility, solder selection has now also been impacted by metals cost.  Today, companies are willing to sacrifice reliability for lower material cost.  As I noted in a previous post, low-Ag alloys are cheaper, but compromise thermal cycling performance. Indium Corporation’s SACM™ alloy provides a lower cost material without sacrificing  thermal cycling performance. If this sounds like an alloy that would be of interest to you, visit www.indium.com/SACM to download the technical paper, or contact a member of our technical team to review your application needs.

Tim

*This post is part of the Introducing SACM™ Series

The attachment of concentrated photovoltaic (CPV) cells is the perfect application for NanoFoil^®. Due to the isolated heating during bonding, less stresses are imparted due to coefficient of thermal expansion. Unlike conductive adhesives or epoxies, NanoBonds® are full metal interfaces which offer higher conductivity values. These 2 points together reveal how NanoBonding incorporates the main advantages of other bonding technologies. This sounds great, doesn’t it? Well, here’s the catch:

Most people have experience gluing parts together, and many handy engineers have learned how to solder wires, pipes, or other common items in the past. In contrast, very few people have ever dealt with a bonding process like NanoBonding. The principal of NanoBonding is simple, but it does require a small amount of research. Luckily, you’re in the right place. From here you can browse the many posts regarding the NanoFoil^® material and the NanoBond^® process. After learning the basics, simply click on one of the contact buttons on this page or follow this link for tech service. Our technical support team can help you become confident with the technology quickly.

Folks,

A reader writes:

Dear Dr. Ron, I need to measure the void content of an alloy.  Is there an easy way to do it?

After a little thought, it occurred to me that the densities of the voided and unvoided material will likely hold the answer.  I derived the result below.  Assuming we know the density of the unvoided material, we can measure the density of the voided material with the Wet Gold Technique, discussed in recent posts, if the voids are not connected (closed cell.)  If the voids are connected (open cell), you could machine the foam to the shape of a rectangular parallelepiped and determine the density of the foam as the mass divided by the volume.

As an example, let’s say you have a closed cell aluminum foam. We use the wet gold technique to measure its density at 1.5g/cc. The density of solid Al is 2.7g/cc.

So the volume fraction of voids is:

Sadly, this technique could not be used to find void content in solder joints, or in BTC (e.g. QFN) thermal pad connections (which are so handily mitigated by using solder preforms.)

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Global Warming Musings:  My recent post on GW generated many comments.   I will be sharing additional reasons why I am a skeptic at the end of posts like the one above. 

It is important to state the distinction between a GW Skeptic (me) and a GW Denier.  As a Skeptic, I am not convinced that the warming trends are alarming or unusual, especially since the atmosphere has not warmed in more than a decade.  Also, I am not convinced that the main driving force for the warming trend up to the late 1990s can conclusively be attributed to human activities.  Lastly, I’m not convinced that even with Draconian measures, we could affect a change that would matter.

The Carbon Cycle

In this post, I would like to share the data relating to how much carbon dioxide is produced and put into the atmosphere.  More specifically, what percent of carbon dioxide generated each year is from human activities. Would it be 30%, 40%, 50%?  The answer is 3%.  The remaining 97% of carbon dioxide generated on the earth each year is generated by natural processes in the oceans and on the land.  See the image below.  The GW argument is that even though human activities are only 3%, this amount offsets the delicate balance that nature provides.  Working with and modeling data all of the time, I find this argument unsatisfying.  Collecting accurate data and developing an accurate model on data like this is difficult.  Making incontrovertible conclusions (it is certain GW is caused by humans) more so. Freeman Dyson, arguably one of the most accomplished physicists of this era, has a similar view:

The models solve the equations of fluid dynamics, and they do a very good job of describing the fluid motions of the atmosphere and the oceans. They do a very poor job of describing the clouds, the dust, the chemistry and the biology of fields and farms and forests. They do not begin to describe the real world we live in...

It is interesting also to note that throughout history the temperature of the earth determined the carbon dioxide content in the atmosphere, not vice versa.

Cheers,

Dr. Ron

.

When dealing with bonding, we often mention CTE (Coefficient of Thermal Expansion). This is a very important topic when designing a soldered interface, whether you are choosing materials that will expand and contract at the same rate or bonding alloys or processes that will handle the stress of deformation caused by these changes. This topic has been explored by hundreds of people, but I like this video because the presenter is both thorough and fun:

I invite you to come to the Southeast Asia Technical Conference on Electronics Assembly in Penang, Malaysia where I will be giving a workshop on SACM™ .

My presentation examines the reliability of low-Ag SAC alloys doped with Mn (SACM) under JEDEC drop, dynamic bending, thermal cycling, and cyclic bending test conditions and compared to eutectic SnPb, SAC105, and SAC305 alloys.

For more information, or to register, visit http://www.smta.org/education/symposia/symposia.cfm#penang. 

Tim