INDIUM CORPORATION

Sure, you could buy some dirt-cheap tabbing ribbon off ebay.

If you want some very awesome solder-coated ribbon and you won’t be laminating your panels over 100°C – I have a much better option for you.

The Indium Corporation makes ultra-low temp tabbing ribbon (melts ~100°C). The advantage? You can use a standard soldering iron and solder solar cells much more quickly because the solder melts more rapidly.

Note: I advise using GS-5454 flux – it may be the only flux that promotes wetting onto the cell as quickly as you’ll be soldering!

Click here to get a hold of this stuff!

The picture above is some of my private stock that I use for testing at work. The picture below is how we package spools – way better than the no-name ball of crinkled ribbon you sometimes get from stock vendors online.

Happy tabbing!

~Jim

最近小忙，少讀書了，也少和大家分享了；不過工作之餘，翻看了一下《A Seat at The Table》一書，覺得裏面有些道理也蠻有啓發的。比如説此書中一直圍繞這個主題來展開了論述“Today, the only thing your customer cares about is value.”

就這個觀點，再對照一下Indium公司的兩個主要系列產品：

²       電路板組裝焊接材料(Solder Materials):  這裡也要分產品而論。對於技術含量較高，工藝使用要求較多的焊錫膏(Solder Paste)材料，重視成品可靠性的客戶們會更多的關注產品帶來的“價值”。 如果只圖便宜的材料，但是用起來“錯漏百出”的，最後還是事倍功半：返工，復修，廢棄率高（特別是浪費貴的不能翻修的板子），產出率低，總體成本也自然高了。 對技術含量較低，工藝已經“模式化”的產品，像錫棒(Solder Bar)，錫綫(Solder Wire),  性价比會更關鍵……在目前日益高漲的金屬原材料市場中，Indium公司考慮到客戶們的成本壓力，也推出了性能可以和SAC305錫棒媲美的有成本優勢的Sn995錫棒。

²       半導體封裝材料(Semiconductor Materials):  整個半導體行業應該算是一個高成本，高投資，高回報（運營得好的話）的三高行業。半導體封裝材料也像是其中的經絡血脈吧，連接各個部分，讓整體最後順暢無阻的工作。半導體各個部分的材料都不便宜，設備更是不菲；對材料性能的表現要求和驗證都很嚴格，畢竟都投資那麽多，不能“功虧一簣”嘛。所以客戶們一般會十分重視產品的價值。 Indium 公司目前提供的半導體材料有：Wafer Flux, Wafer Paste, Micro Spheres, Flip-Chip Flux, Substrate Paste, Ball Attach Flux, Die-Attach Paste/Wire, PoP Fluxes, etc. 

Indium公司還為大家提供散熱界面材料(Thermal Interface Materials)，工程焊料(Engineering Solders)，薄膜光付太陽能板製造材料&太陽能板組裝焊接材料(PV Solar Materials)，和銦金屬及其化合物等。 這些材料使用在比較領先的應用中，新興行業，或是細分市場中，客戶們都十分重視產品和服務能給自己帶來的價值。

Cheers!  

Pic: Indium Corporation

PS: 前些日子看了中央4台的《第三屆漢語橋在華留學生漢語比賽》，感慨不已！除了感嘆這些留學生們對“那麽難”的漢語的精湛掌握，對中國文化和歷史的了解，甚至對中國的熱愛；更感慨的是，這些活動也説明了祖國的強大！現在越來越多的留學生們來中國學習，想進一步了解中國，和中國人民交流；中國話也在慢慢傳播到全世界！以前中國學子們苦讀英語，考TOFEL, 雅思，GRE什麽的；現在金髮碧眼的學生們也在場上比拼誰更了解我們的“四書五經”了，哈哈！

The word ‘cadmium’ (Cd) has a negative connotation to anyone who deals with solder alloys or health and safety regulations. If you are using toxic cadmium sulfide as a buffer layer for CIGS PV cells, I urge you to explore indium sulfide (In₂S₃) as a replacement. Alternative energy should focus on being environmentally conscious, starting with the bill of materials for the solar cell.

The following is an example of how a simple procedure like cleaning a soldering iron tip can make a world of difference in the quality of a solder joint. Eric Bastow responded to a customer after doing some testing in the lab – and confirming that a clean iron tip contributes to a clean solder joint:

“As I mentioned in our conversation, I did not think that a flux coated preform would fare any worse than a cored wire in a hand soldering application where charring is concerned. Rosin is rosin is rosin, regardless of whether it is within a cored wire or coating a solder preform. I did a quick experiment to see what would happen.

Using a Weller WS80 soldering station, set to an abusively high temperature of 850F/455C, I soldered some .250” square x .005” thick Sn63 preforms (folded-up as small as I could do by hand), flux coated with 1% NC9, to a nickel metallized FR4 test coupon. The contact time of the iron to the solder was ~5 seconds. The results look pretty good. The charred flux that you do see is flux that burnt to the iron and was transferred to the solder from the previous preform. I would anticipate this sort of appearance with a flux cored wire, as well, used under these conditions. I believe that with frequent cleaning of the tip, the amount of unsightly flux residue with be minimal, especially if a more appropriate iron temperature were used.” -Eric

The bottom image is what happens when you don't clean a soldering iron tip.

Soldering Basics

Folks,

I have mentioned numerous times that the first purpose of RoHS is to help make recycling easier. So RoHS was developed to support WEEE . One would imagine that, in doing this, the EU was primarily concerned with recycling in the EU.

Fortunately, thousands of folks in the 3^rd world will benefit from RoHS, as much recycling is performed by poor people in these countries. When they recycle non-RoHS-compliant scrap electronics, they are being poisoned by lead, cadmium, mercury, and smoke from non-banned organic compounds. This sad situation was again recently brought out in a New York Times article.

As more and more waste electronics becomes RoHS-compliant, the amount of toxic material that these people are exposed to will become less and less. It still shocks me that, when I point out this benefit, a person comments something like this:

“You mean I have to put up with RoHS just to help these people?”

It is my fervent hope that very few of us feel this way.

Cheers,

Dr. Ron

Image source.

剛剛看見一個關於如何使用AuSn預成型焊片 （金錫，主要是Au80Sn20的共晶材料）來做laser bar bonding的短文和錄像，頗受啓發。在此與大家共享。短文和錄像轉載在Finetech:  http://www.finetech.de/micro-assembly/applications/laser-bar-bonding.html

Laser Bar Bonding

 In comparison to single lasers, laser bars consist of several single edge-emitting lasers comprised in a silicon bar. Bundling the light results in significantly increased output power as needed in a wide range of applications.

Laser bars are high power products, applied wherever small and efficient light-emitting units are needed. They mainly serve as pumping sources for optical resonators of high power lasers. Another field of use can be found in medical appliances.

What are the challenges?

                       Sensitive components with brittle materials and optically active areas

                       Delicate edges and facettes

                       Perfect coplanarity required to ensure proper thermal management

                       Highest placement accuracy needed to ensure defined overhang

                       Stacked mounting (lasers to submount) requires different solder materials with their appropriate profiles

                       Void free bonding

                       Solder materials are prone to oxidation, process integration required

                       High magnification of large components

                       Indium bonding under process gas atmosphere

過去我也有一篇blog寫了關於Indium公司的AuSn材料的，請分享。

Cheers!

First image & English content source: FineTech; AuSn image from Indium Corporation.

This week's topic is both wafer bumping and substrate bumping with solder paste, and the issue of powder size. I’ve recently been dealing with some issues from customers who are concerned with the question of “how small a solder powder particle do I need, to achieve a certain bump height or bump diameter”? There are some "rules of thumb" on this in the electronics assembly industry, and I'll go into them later. In my next posting, I'll show why they may not be relevant or appropriate for the standard waferbumping process.

To begin: there are lots of ways of forming deposits of solder in a small form factor, and solder paste printing remains one of the most reliable, although yield drops dramatically at below 120microns pitch (some say 100microns).



If you are stencil printing solder paste, there are two guiding principles:

1/ Sbiroli’s Rule: The width of the stencil opening must be 7 particles or greater. By the word “particle”, we err on the side of caution and refer to the highest controlled particle diameter. For example, in the case of a type 3 paste, this will be around 45microns, although you should refer to my previous posting on the subject of powder size standardization (for types 5,6,7 and so on) and the poor state that that is in.

2/ Anglin’s Rule: You should not exceed an aperture ratio of 1.6. The aperture ratio being a measure of the aperture wall area to “open area”. As I showed in a previous post, this rule originates from boundary-layer-type considerations of release from the stencil walls by the pseudoplastic/thixotropic solder paste material. 


 

What if you are NOT stencil printing? The Flip Chip International (FCI) “drive in” process, which uses a developed photomask as a kind of “in situ” stencil for solder paste, allows for 5 or 6 print strokes using a soft squeegee to ensure that each aperture is filled. There are no problems here with stencil release, so how do we go about thinking of what particle size is required in this and similar processes? I think I have the answer: more next time.

Cheers!

Andy
 

nan·o·tech·nol·o·gy [nan-uh-tek-nol-uh-jee, ney-nuh-]
-noun
any technology on the scale of nanometers
(care of dictionary.com)

So it can be cliche to start with the definition straight from the dictionary, but the definition clearly points out the problem with the understanding of nanotechnology...there is very little.  Trying to define nanotechnology broadly is like trying to lump all items in a grocery store that are in a jar into the same aisle.  Just because pickles, peanut butter, and garlic all come in a jar doesn't mean you need to lump them in the "jar aisle". I'm not sure my stomach can handle that shopping experience. 

In a response to this kind of understanding, this week the International Organization for Standardization (ISO, you know like ISO 9000?) released a new technical report to help define and categorize nanotechnology. Instead of treating the technology as one big lump of the same material and "organizing by jars, or jarring it", it is acknowledging that all nano isn't created equal.   In the report, titled ISO/TR 11360:2010, Nanotechnologies – Methodology for the Classification and Categorization of Nanomaterials, it treats the constituents of nanotechnology as part of a family tree.  So your garlic may come in a jar all chopped up, but it is classified with the veggies and onions because it is more closely related.  In much the same way, carbon nanomaterials and gold nanoparticles are nano and "in a jar," but carbon nanomaterials are a separate class of material that can now be classified on a separate tree or "aisle."

So what do you think?  Is this a good way to classify nanotechnology?  Are you glad that ISO is getting involved in the conversation?

最近在和同事Tim Jensen聊Indium公司的Indium8.9系列的焊接材料，爲什麽能夠很好的解決面前業界的一系列焊接問題，主要是因爲我們在設計Indium8.9系列的焊接材料時候，充分考慮到“Oxidation Barrier”的因素。

• Oxidation Barrie能夠大大減少，甚至完全消除枕窩效應(Head-in-Pillow defect). 枕窩效應是因爲BGA球和solder paste在回流前的preheat or soak time階段分開了，在熔融過程中，表面被氧化；儅BGA球和paste再次接觸時，表面被氧化層太厚了，所以整個焊點沒有完全融合好。如果有良好的Oxidation Barrier, 那麽能大大減少BGA球或是paste在熔融過程中因爲分開而被氧化。 

• Oxidation Barrie 能夠提高精密元器件，小開口印刷的焊點的結合。小開口的下錫中，4號錫粉的表面積(powders’ surface area)其實是比3號粉增加了，但是助焊劑(paste flux)沒怎麽增加，那麽在焊接過程中，有些錫粉表面的氧化物可能就沒有被完全清洗乾淨。被氧化的錫粉不能和整個焊點完全融合，形成良好的焊接點；而是在焊點附近出現一串像葡萄一樣的小珠子，我們也叫做graping defect。 有了好的Oxidation Barrier, 就能夠更有效地預防graping defect, 提高小開孔印刷焊點的融合。

• Oxidation Barrie能夠減少留在電路板上的活化劑activator，增強電性能的可靠性。Oxidation Barrie 能夠防止焊接表面被氧化，activator是清洗表面被氧化的部分。如果有了良好的Oxidation Barrier，那麽activator 就可以相對減少。回流后留在電路板上的activator 也少了，那麽也減少short cut 等現象，提到電性能可靠性。

Cheers!

Pic: Indium Corporation

Folks,

Answers to the quiz of a few weeks back......

Phil and Rob had agreed to ask the GM if it was OK to ask the tech and engineers at some of their subcontractors to take the test anonymously. Over a period of two months Phil and Rob got 52 people to agree, almost all of them after Phil or Rob agreed to take them to lunch. They asked Patty to grade the “exams.” Today Patty would reveal the results.

“Phil, this is one of the best bets I have ever made,” teased Rob.

Everyone at the lunch table chuckled, but the look on Phil’s face said he expected to lose. Rob has said that he thought the average score would be less than 70%, Phil insisted that it would be greater than 85%. In asking the different folks to take the test, invariably Phil started asking questions not on the test. He was surprised that no one knew what tin pest was. He even asked how to time balance a chip shooter and flexible placer, only one in twenty knew.

As Patty approached the lunch table, the ensemble held their breath.

“OK, Patty, tell us the bad news,” Phil said in a resigned tone.

“Rob wins, the average score was 58%,” Patty said getting to the point. “Here are the answers and percentages on each problem,” she went on:

1.    What is the composition of SAC305?
96.5% tin, 3.0% silver, 0.5% copper. 60% got this right.

2.     What are tin whiskers?
Tin whiskers are metal whiskers that can “grow” from tin plating on component leads. They are mitigated by 2% bismuth in the tin, a nickel overplate of the lead copper, a matte tin finish, and a few other mitigation approaches. 40%.

3.     In a stencil aperture, what is the area ratio?
The ratio of the area of the aperture opening divided by the area of the side walls. This ratio is typically used for circular and square apertures. It is equal to D/4t, where D is the diameter of square side and t is the stencil thickness. 40%

4.    What is an approximate peak temperature for a reflow oven in lead-free assembly?
Any answer 235 to 250C accepted. 90%

5.     A board is inspected after wave soldering and one lead is not soldered to the board. The board is run through the wave solder machine again and has the same defect on the same lead. What is the most likely cause of the defect?

a.       The solder temperature is too low.

b.      The pad on the board is oxidized.

c.       The preheat temperature is too high.
b 70%

6.     What are local fiducials on a PWB for?
Local fiducials are located near the pads of a component with fine lead spacings to assure accurate placement. 70%

7.     What does "thixotropic" mean in regard to solder pastes?
The viscosity decreases with increasing shear stress. Hence, during printing the viscosity drops as the paste is forced through the aperture, aiding good aperture fill. It increases as the printed deposit rests, minimizing slump. 20%

8.     A chip shooter places passives at a rate of 36,000 per hour. It is placing 300 passives on a PWB, how many seconds will the chipshooter take to place the passives on one board?
300/36000 = 1/120 hr = 30 seconds. 90%

9.     A reflow oven belt speed is 100 cm/min. The PWB is 40 cm long. What is the minimum cycle time that the oven can support?
The amount of time that the belt needs to cover 40 cm is 40/100 = 0.4 minutes = 24 seconds. This is the minimum cycle time the oven can support. 40%

10.   What is "tombstoning"?
Tombstoning is observed when a passive component's terminations experience unequal wetting forces which are strong enough to lift one end of the passive so that it looks like a tombstone. 60%

Overall average score 58%.

“Wait a minute Patty, your answers are too demanding,” Phil shouted.

“Calm down Phil, I gave full credit for anything close,” Patty responded.

In unison, almost everyone at the table sighed “Yikes.”

Patty interjected, “One person who received a 70% commented after completing problem 9, ‘I didn’t think I would need a PhD in math to do this quiz.’ “

All agreed that organizations like the SMTA and IPC were more needed than ever.

I had a call with a few engineers today who wanted me to answer a question, “Which solder paste do I pick for my application.” Sure there were a few application-specific details that I feel were too specific to discuss with a general audience, but I think I can answer the question for any of you that are out there wondering the same question while reading this.

It’s an easy answer really; start with SR-8 unless:

1)     You are using laser reflow equipment.

2)     You have noticed solder spatter issues related to your design.

3)     Your company or end customers require you to use only halogen-free materials

4)     The residue must be clear and almost non-existent (ultra-low residue levels)

If you said “yes” to any of the above, you’ll want to try SR-7 (as long as you have nitrogen reflow capability). If you said yes to answer 3 (halogen-free) but you do not have nitrogen reflow capability, try SR-089.  

Jim’s note: This post was written in August 2010 – but it will be available to anyone searching for the info for quite some time. For updated information on newer solder pastes, send an email to Solar@Indium.com. Thanks! ~Jim

Welcome! I am a chemical engineer experienced in an R&D setting and jumping into a new position in marketing here at Indium Corporation. Initially, in this blog, I will focus on my journey getting started, learning all the new facets of the business here, and transitioning from my former R&D mindset into something more outward facing and communications-based. I am relatively new to this world of social networking too, so I’m sure there will be plenty of growth in that direction as well. Hopefully, you will enjoy taking this journey with me, learning vicariously. I would certainly appreciate any pointers from you. 

Officially my job title is “Product Support Specialist”.  I’m learning that it means a lot of things, for example, being an expert in PCB assembly, the different products that are used for PCB assembly, and being able to convey that useful information to everyone that is interested. “Everyone” really could be anyone in this case: existing customers, potential customers, customers that haven’t even thought about how solder paste or another product might make their process easier, people who just have an interest in electronic materials… and people here at Indium, R&D, production, our sales team, and the list goes on. In time this blog (with any luck) will be a good resource for a lot of helpful information to all of these people.

As I am completing my first week here at Indium, I am feeling very optimistic about my new position and my capacity to contribute. Overall, this week has been like riding a wave of information, and just trying to scoop up as much as I can. I have been surprised by how much my previous experience in electronics materials is helping me. Even though the materials here are significantly different, I have been exposed to a lot of the same processes before (screen printing, mixing, metal powders, etc.), so I just have to make the mental links and note the differences. For instance, I was fascinated, while touring one of our manufacturing facilities yesterday, that we are using the same mixer I used in my former company’s pilot lab, just about 20 times larger. Also, we are packaging some of the material in the same cartridges and syringes I had previously filled by hand on so many occasions.

On a more personal note: Before starting Monday, I had mostly been filled with a sense of gratitude for having found a job that I really love, and a little bit with some apprehension about fitting into a new role, living up to all of the expectations (from myself, my co-workers, my new boss…). I suppose a long period of searching for employment, with all of the probing and feelings of rejection and such, really does change one’s perspective of their competencies. It has been difficult in the past months listening to the news and hearing reports of unemployment numbers staying the same or getting worse, and in addition having benefits for unemployment on shaky ground. In some ways it felt like people who were still employed might not understand how difficult it can be to find a job, even a job that doesn’t live up to the expectations one might have had 5 years ago. I just thought that I should note that there is still very much reason to hold on to hope: it is possible to find a wonderful job that fits your qualifications, and continue on after all of this economic turmoil. What was most important during my time searching was to keep searching for that job that would further my career the way I wanted it to, to keep applying to positions that might seem out of reach at the time, and to not get discouraged, because despite all of the unanswered emails and resumes, only ONE needs to come through… and that one could be awesome. Since Monday, of course, my doubts have been fading quickly, and I am still filled with that sense of gratitude, which I don’t think I would have appreciated without having gone through these tumultuous times.

前段時間和Indium公司研究波峰焊助焊劑的Jim Hevel一起出差，進一步了解了波峰焊助焊劑這種產品。 雖然電子產品組裝的焊接技術從波峰焊技術(wave soldering)到表面裝貼(SMT)轉變以來，波峰焊助焊劑從使用比率來講是少了；但是因爲整體的市場在增大，通孔焊接技術還是具有一定成本的優勢，某些特殊元件的焊接需要，還有部分簡易產品和不需要微型化的產品等因素，通孔焊接技術還是存在並佔有一定市場的。那麽波峰焊助焊劑也一直在業界被廣爲使用。

在波峰焊技術的焊接過程中，大家最關注可焊性(solderability)兩方面的問題：Hole Fill & Bridge.  良好的爬錫/填充孔，還有不要出現橋接現象。Jim說他在設計公司系列波峰焊產品的過程中，除了根據客戶要求和行業IPC規定外，solderability就排第一位了。請看以下表格。

適應市場無滷化的需求，Indium公司有酒精基(Alcohol based)和水基(VOC-Free)的無滷波峰焊助焊劑。

Cheers!

Picture: Jim Hevel with Indium Corporation

PS: Jim來自Indium公司的芝加哥工廠。剛好Jim在西雅圖那兩天，棒球賽是西雅圖水手隊對決芝加哥白襪隊(Baseball, Seattle Mariners VS Chicago White Sox)，西雅圖主場。Jim第二天問我有沒有看球賽…不熱愛棒球的我當然什麽都不知道。 經過Jim給我的棒球知識補充，讓我豁然開朗！怪不得某一個客戶曾經問我支持哪個隊，當時我心裏還嘀咕要不要請他一起看棒球呢…現在回想，人家只不過以爲你是“當地人”，肯定知道當地的球隊，找你侃侃對球隊的看法而已，哈哈。

Some people collect stamps, or coins, or baseball cards – my father collects hardware. Almost every time I go to my parent’s house I notice a few jars or boxes of bolts, nuts, screws, washers, and clamps. They are bought in bulk and sorted by size. I used to think it was ridiculous to do this, but my Dad actually uses enough of the hardware to save money, and I have never needed to run to the store during a project to get a special size piece of hardware. An old bolt may not look as pretty as a new bolt, but in applications that are simply for utility, an old bolt works just as well.

Solar panels that do not live up to visual specifications also share a utility, much like old bolts. They are certainly cheaper - and for a solar farm, small imperfections may not matter to the customer.

So now it’s my time to collect something. I’m not looking to collect old hardware or utility grade solar panels, I’m searching for the different criteria that module assemblers use to determine if modules are fit for residential or commercial use. This information can be used to help set the (IPC) standards for the industry. If you have information that could help, please send it to jhisert@indium.com. Thanks!