Indium Corporation Blogs

It is common to hear people that are skeptical about CIGS technology ask questions like:

• "Aren't indium and indium tin oxide (ITO) thin film deposition processes wasteful and inefficient?"
• “Aren’t we going to run out of indium soon? Doesn't the world use more than we produce!”

What are the truths?

Here they are:

WASTEFUL: A well-run process is NOT wasteful. Why? Recycling!

At first glance, a process like indium planar target sputtering seems ridiculous – generally only 30% of the indium actually makes it onto the substrate it is destined for (and that’s in a well-tuned process). As it turns out, the material that doesn’t land on the substrate is too valuable to just scrap. This translates into recycling, a lot of recycling…

According to presentations given at Minor Metals 2012: “indium production will total 1,500-1,700 tonnes in 2012, with virgin supply accounting for around a third of total output”.  It’s incredible that recycling accounts for such a large percentage of the indium used in the world today.

INDIUM AVAILABILITY AND SUPPLY: Another important conclusion made at the conference was (as reported in Metal Bulletin):

“proven indium reserves from existing mines at 50,000 tonnes, a volume that will be sufficient to satisfy demand for the next 75 years”.

While it’s not news at Indium Corporation, it is definitely assuring news for those looking to get involved with CIGS technology.

~Jim

Q1) What the heck are we looking at in this picture?

A1) It’s a CuGa (copper gallium) target being sputtered at Angstrom Sciences, Inc. test lab. Since CuGa rotary sputtering targets are becoming more popular in the CIGS deposition industry, we wanted to see how they work with AS cathodes. The result: a winning combination!

Angstrom Sciences Lab








Q2) Why haven’t Cu-Ga rotary targets been more popular for production of CIGS solar cells (a thin film technology)?

A2) The big problem has historically been segregation of the copper and gallium in traditionally cast targets. This was a hot topic for those who stopped by the booth at the Society of Vacuum Coaters TechCon and checked out our full size CuGa display target. It is only natural to question if a display piece actually works well in a production sputtering process. In order to make this product work, we had to manufacture it using our proprietary hybrid consolidation technique.

Without giving away all the juicy details, I can tell you that it was a learning experience and that there were some setup issues that led to improved applied power settings. Our customers have been pleased with the results of our CuGa targets, although the fine tuning is proprietary to them and we cannot share their learnings. Now we have a much better understanding of the maximum power we can use for this type of target. That's why it was so important to work with an equipment supplier.

One thing that is obvious from looking at the spent target is the lack of an erosion groove from magnet dwell - a nice feature of the magnetron that was used. The spent target is on display in my boss’ office. It serves as a reminder of the time we spent with the Angstrom Science guys sputtering the target, gathering data, and learning from the team.

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

“Hi, this is Jim Hisert. I just read an interesting article and I wanted to share it with you. In the 2010, October edition of PV magazine, the cover story on page 70 was pretty interesting, so here it is…

It’s called Rotatable Rotatables, and it discusses rotatable targets. The really nice thing about the article is: it goes through the physics of sputtering and gives you the background of what magnetron sputtering is all about. Then it talks about different kinds of targets. It talks about the difference between rotatable targets and planar targets, the different compositions of targets. And then it also goes into talking about the supply of indium and gallium, different target materials, as well as the difference between thermal vapor deposition and sputtering – the advantages and the disadvantages. It even wraps up with refining and recycling of the material and talks about the process overall.

So I advise that you check this out. It’s in the latest (October) edition of PV magazine. Thank you.”  ~Jim

Keywords: Solar, sputtering targets, copper indium gallium, CIG, indium, thin film technology

This blog has been in existence for a little over two years now, and we would like to thank our readers for the feedback and inquiries you have provided. I welcome your comments on what you would like from us. Leave a comment below, or email me at jhisert@indium.com.

And now a look back on past topics of interest:
 

Grid Ink, Silver Ink, Conductive Ink

Bismuth/Tin Tabbing Ribbon, A Low Temperature Pb-Free Alternative

Plated Metallization for C-Si Solar Cells

Increase Packing Density for Evaporation Crucibles

Photon’s 5th PV Tech Show 2010 USA

IPC Solar Standards Update

Solder Shelf Life as Explained by Eric Bastow

Tips to Speed Your Solder and Flux Selection

What's Happening in the Technical Service Department 

A Day in the Life of a Tech Guy

A Clean Laboratory

CIGS for Beginners

3rd Renewable Energy Expo 2009 in New Delhi, India

Solar Products and Representatives

Kleenex®, Google™, FedX®, CIGs?

Indium Solar Products Reunited

Trade Show Visitors Love the Ground Floor

Solar Product Data Sheets

Intersolar 2009 – What Barrier to CIGS Technology?

Concentrator Photovoltaic Systems - Will they reach 50% Efficiency?

Standards for Solar Panel Manufacturing

Solar Panel Certification: “Barrier and Benefit” Reviewed by Eric Bastow

Low Temperature Metallization Paste

What Will Your Interest Be At InterSolar? Meet the Bloggers And Let Us Know.

Share Your Solar Images

SAC vs. Sn/Ag for Solar Soldering

Solder Thickness for PV Interconnect

What is Bus Ribbon?

Standard PV Interconnect Ribbon Sizes

No-Clean Flux

Photovoltaics in EMS Sector

PV Interconnect Products

Eric Bastow - East Coast Technical Support

Mario Scalzo - West Coast Technical Support

Au/Sn Sputtering Targets

SMT Goes Solar

A Trip Down Memory Lane 

More Information About Metallization Paste

A year in the Life of a Solar Blog

CIG Target

23rd European Photovoltaic Solar Energy Conference and Exhibition

TCO choices for CIGS manufacturing 

CIGS Absorber Layer Electroplating

No Slump Metallization Paste

Meet the Bloggers

CIGS - Can sputtering make a breakthrough?

Fluxes for Soldering Tabbing Ribbon

Computer Brain vs. Solar Photovoltaic

Beam it down from space

Selection of the Optimum Lead-Free Solder for Solar Tabbing Ribbon

Record Makes Thin-Film Solar Cell Competitive with Silicon Efficiency

Why Thin-Film Solar Cells are Here to Stay

Hot Rooftops to Flashy Digital Cameras

Synchronize Your Solar Cell

Solar Conversion Efficiencies  

Government Support is the Key

It's Just a Beginning ...

In an evaporative deposition process, source material is evaporated and then condensed onto a substrate which is being coated. One of the common uses that our solar team encounters is the deposition of indium (provided as shot) for CIG thin film technology.

It’s an easy concept: if you can fit more indium shot in a given crucible, the evaporation process can run for a longer period of time before material needs to be added. The traditional form of solder shot is a teardrop shape, which is easy to produce as a bulk form of solder. 

A newer version of shot is now available without the tail, we call this ‘round’ or ‘tailless’ shot. This material is similar to solder spheres, but not as precisely spherical. Compared to traditional shot, round shot offers a packing density increase of 15% - 20%. This means you can fit more source material in a given crucible, which can keep your evaporation process running longer, more efficiently, and more profitably.

I caught up with Alan Rae after a recent IWLPC committee meeting, where he jokingly asked me to, “Stop asking important questions” - LOL! He was kind enough to give me a few moments of his time to share his wit and wisdom, and answer some technology questions that, yes, I thought were kind of important…

[Andy Mackie] You’re increasingly being seen as “Dr Nano” by the electronics industry – how did you arrive as the focus of so much of this technology?

[Alan Rae] At the start of my career I was in the structural ceramics business. In the days of “ceramic fever” in the 1980’s the mantra was sub-micron and monosize (monodisperse) for lower temperature processing and better properties. It worked. Then at TAM Ceramics we made “sub-micron” barium titanate and other ceramic materials but we didn’t call it nano then. When I was at Cookson Electronics in the early 2000’s we started to see nanotechnology emerging from the woodwork with people saying the same about nanomaterials for the electronics industry. Then I joined NanoDynamics in 2004 and realized the scope and potential, ranging from semiconductors to touch screens to printable electronics, to LED lighting, to solar power, to materials such as nano solders, dielectrics, conductors…the list is growing but the leitmotiv is the same – small, monosize, tightly-controlled. 

[Andy Mackie] OK, so Nanotechnology has been a buzzword for quite a while – is there a clear definition yet, and what current uses are there for nanotechnologies that may not be immediately obvious?

[Alan Rae] Well, the definition has been really tough to derive – ISO TC 229 “Nanotechnologies” came up with a definition that one dimension of a particle, needle or plate should be less than 100nm but it’s really tough to define…should all particles be less than 100 nm? 50%? Any? And should it be exactly 100nm? There are a lot of opinions. The Woodrow Wilson Institute lists over 800 consumer products containing nanomaterials on the market now – industrially the products range from semiconductors, to fillers in packaging materials and underfills, to antimicrobial and self-cleaning coatings for phones. Solar panels, especially thin film ones, depend on nanomaterials in their manufacture.

[Andy Mackie] What is in the pipeline for nanotech electronics and semiconductor interconnect materials? I know that nanosolders are starting to gain ground in some areas – what else is upcoming?

[Alan Rae] Much of the work in nano metals is being done by universities and small companies – for example my small company is working with Purdue and the Air Force to develop a novel solder technology – but commercialization will come by partnering with established companies like Indium Corporation, who have the distribution and technical support so that customers will be comfortable with a new material. Cost and reliability are king. Indium is already in the reactive nano foil business; there are existing and near-term applications for silver, silver-coated copper, alumina coated boron nitride and their combinations in adhesives, shielding materials and thermal interface materials.

[Andy Mackie] Several years ago, quantum dots were being promulgated for tunable band-gap detectors and quantum computers. How close are quantum dots to seeing real uses, and what else is on the horizon?

[Alan Rae] Quantum dots are unique and have great potential in medical imaging and as frequency shifters for LEDs. The markets haven’t developed yet because of the cost and because some of the best dots are cadmium (toxic metal) based. I’m working with a group at University of Buffalo which has a silicon quantum dot process that looks like a promising alternative. Quantum dots will have their time…but not just yet. In terms of new developments – they range from core shell and modulated structures for thermoelectric to replacing indium tin oxide with carbon nanotubes or graphene. The US National Nanotechnology Initiative tracked $1.6 billion in Government spending (check out www.nano.gov) in the last year at Universities and small businesses and NSF has set up centers of excellence at Cornell and other great universities that are really working hard to translate science into technology so we can make practical products.

=======

Alan, many thanks for your time, and for sharing your insights with us.

Cheers!  Andy

Having worked with NanoFoil® for over two years, I've tried just about every way possible to explain what it is, where it comes from, and why it is useful. My interchanges with engineers and non-engineer friends and colleagues used to go like this...

Tommy: NanoFoil...it's kind of like aluminum foil in thickness and look, but a little stiffer and when you put energy into it, like a spark, it heats to 1500 degrees Celsius (which is hotter than lava in a volcano) for less than a millisecond!

My engineering and non-engineering friends display puzzled looks, you know the ones you get when you start explaining that your favorite sport is water polo and it has nothing to do with horses...ok the look you have right now

Engineering Friend: Umm so what can I blow up with it?

Non-Engineering Friend: So wait, if it's that fast and that hot, I bet you could make really fast grilled cheese. Have you called Healthy Choice yet?

Good Grief!

Al + Ni -> AlNi  (You didn't know there'd be chemistry involved did you?)

So you see why it isn't great for melting grilled cheese now, right?  It would only singe the outer bread layer, at best.

There are many applications for NanoFoil, but it is most commonly used for joining two components together. That is, components that have solder pre-applied (pre-tinned). In this situation, the NanoFoil, as the heat source, remelts the solder and reflows the joint WITHOUT the heating the nearby components or substrates!

So, while I won't be calling Healthy Choice any time soon, there are many applications where NanoFoil is useful...LEDs and CPV bonding for thermal management, and sputtering target bonding for higher power just to name a few.

Stay tuned (subscribe via RSS or email - below) for more applications and for more about how NanoFoil is used to bond, and just more about nanotechnology.  If you think I got some weird looks from my friends about NanoFoil, imagine what they said when I told them about the nano...pants?

For more information, visit here.

Living in NY (or anywhere on the East Coast of the United States) and working with the solar industry usually means traveling to California. We don’t have as much sun, and we certainly don’t have as many solar customers, conferences, or venues to learn about solar technology.  Luckily, the College of Nanoscale Science and Engineering, SUNY at Albany (NY) is hosting a 2 day photovoltaic technology course April 20th and 21^st. Ernest Levine is teaching this course, you may know him from his IC Fab training that he provides a few times a year. I haven’t been to his solar training yet, but I know that he covers IC fab in a way that everyone can understand – plus he has the background to answer those tough questions that veterans throw at him. (You know, that one guy in the back that is just dying to stump the professor…)

According to Ernest: “This PhotoVoltaic Technology course covers this subject starting at the atomic level and building up to an atomic understanding of the inner workings of a photovoltaic cell.  Using a comprehensive in part animated slide presentation we will see how the charged particles move as well as cover details of the governing equation and how it came about and important controlling factors in efficiency and manufacturing of both thin films and crystalline Si. This includes amorphous Si, CdTe and CIGS as well as GaAs and concentrated and tandem cells. All you need to bring to class is a desire to learn and I will teach you.”

For more detailed information send him an email at elevine@uamail.albany.edu  or call him at (518) 437-8623.

For a interesting and very technical introduction to CIGS (copper indium gallium selenium) technology, check out the 3^rd quarter 2009 edition of Photovoltaics International Magazine – page 112.  This article by ZSW is a good primer to get you up to speed with this thin-film technology.  (This blows the Wikipedia "CIGS solar" description out of the water!)

The article is a good read for those of you looking into CIGS technology because it goes well beyond the overview of what CIGS is with discussion of chemical and structural analysis of thin-film cells. 

A reader of this blog recently mentioned: "I am interested in what products could be sold by manufacturer's representatives."  That is a large question, considering the evolution that we have come to expect in the solar industry.  To answer that question involves first breaking up the industry into 2 separate sections, front and back end solar assembly.  Front end assembly involves the process of making the solar cell.  Back end involves connecting cells together and assembling them to create a useable device.

Both front and back end products are going to be geared to the customer's technology.  For instance, if I was purchasing materials for a large thin-film manufacturing company and someone boldly offered me glass filled high-temperature metallization paste, I would tell them to come back when they know what they are talking about.  (In reality, I'd be nice – even though it's an incredibly ignorant mistake.)  With that in mind, let's focus on what back end products a representative might be offering for crystalline and thin film solar customers – assuming that back end begins after metallization:

• Outsourced Solar Cells
• Tabbing Ribbon
• Bus Ribbon
• Tabbing Flux
• Solder Paste
• Preforms
• Solder Wire
• Tacky-type Fluxes
• Tabbing Equipment
• Rework Equipment
• Test Equipment/Services
• Packaging Materials
• Junction Boxes
• Laminate Materials
• Silicone/Sealing Materials
• Passive Components
• Ovens
• Frames
• Gloves / Lab Coats / Safety Equipment

I probably left out as many possible line items as I included, but I hope you get the idea.  Feel free to add the ones I forgot in the comment section below.

~Jim

Figure 1: 15% Voiding with air reflow

Figure 2: ~0% Voiding after vacuum reflow

Figure 3: Multiple voids

While at the Semicon West 2009 show in July, I had a chance to sit down with Herr Klaus Roemer of Pink GmbH. PINK is most famous in the die-attach and power module manufacturing world for their reflow ovens with vacuum, but are also known in the medical and aerospace industries for manufacturing extremely high precision, one-off, vacuum equipment for applications as diverse as particle-accelerators for ion bombardment, and large-volume chambers for helium leak-detection. I asked him some questions about Pink vacuum soldering technology.

Cheers! Andy

 

I don't know about you, but I 'FedX' packages, I 'Google' terms I want to know more about, and I blow my nose with 'Kleenex'.  Those terms have become more than a standard, they have actually become an action in themselves.  Maybe one day the major classification of solar technologies will be "Crystalline cells" and "CIGS cells".  I bring this up only because one technology will surely find its way to the top in the race to be the most popular thin film technology.  Will we 'CIGS' a rooftop or 'CIGS' a solar farm?  Interesting…

This year at InterSolar I learned how misleading old (mis)information can be.  In a business as rapidly developing as the solar industry, you just can't cling to information from 2 or 3 years ago. 

Of course there was a good deal of discussion about which thin film technology would prevail in the future.  The argument against CIGS is usually based on the faults of CIG deposition, but this is an argument that is no longer valid.  High quality CIG targets are currently available and are being used by some of the top solar fabs.

It's good to know where we came from, but the solar industry is evolving way too fast for old information to be used in decision making.  As a way to help, let me know if you see any out-dated information if you are looking through old Solar Materials blog posts.  I will make sure those posts have the correct information showing the current status of the industry.

Thin Film PV Cell

最近小忙，只能凑凑杂文，不好意思。

1． 先请教大家一个问题，在太阳能光伏薄膜技术(PV Thin Film Technology)中, 哪种技术在中国领先？爲什麽呢？ 太阳能光伏薄膜技术，主要有这几种：

• Amorphous Silicon (a-Si): 非晶硅
• CIGS: 铜铟镓硒(Copper Indium Gallium Selenium)
• CdTe: 碲化镉   

2. 关于公司裏的开会。 前天中午看牙医，他又准备给我嘴巴里面打麻醉针了。"怎么这次又打？我还以为这次的小治疗不需要了。怎么每次下午我要开会发言，都会遇上你的麻醉针？叫我等会怎么说话呀？"牙医问"会议很重要吗？"我郑重其事的回答"当然！无论和谁开会，每一个会议都是重要的。因为除了自己能给会议带来value之外，也是展现自己的机会，别人也会在心中评价你的…"牙医笑道"Such a corporate girl! Please be quiet for now."然后他毫不手軟一针下来，我这个talking-box (话匣子)也慢慢地少话了…Anyway, 在公司里面，对于每一个会议都认真对待，做好准备，應該沒錯的。下次我看牙医前要问清楚是否要打麻醉针了，不然很有可能会一边说话一边不自觉地流口水的。

3.  无卤化 (Halogen-Free): 明天开始会去美国西部休假10天。我知道自己会被那里的更纯净的自然景色给shock的，也更加会想起祖国（或是第三世界国家）在电子垃圾废墟中的人们(e-waste)…还是老话，今天，你无卤化了吗？   

Concentrator Image Source: Meta Efficient

Honestly, the solar business unit here at Indium is growing tremendously, and I'm proud to say that it looks like it is attracting the most interest out of all the markets we service right now.  Indium engineers from around the world are converting to "the solar side", and I love it!  Tony Howard from our European office has been digging into solar technology and has this to say:

"I was recently tasked to understand the Concentrator Photovoltaic Systems (CPV) a bit closer and get a feel for the efficiencies available and the future trends. CPV is the super high-end of PVs.  Cell efficiencies have been increasing fast over the past few years are now around 43% and will produce 35 watts from a 1 cm square multi- junction chip. They are costly, require a tracking system and sunlight magnification by use of either a Fresnel Lens or parabolic mirrors, their use is mainly restricted to space satellites and terrestrial solar farms. There is talk of the efficiency increasing to 50% by 2015.

I recently visited a CPV customer who suggested that the efficiency levels are improving all the time and they are becoming very competitive to the Thin Film and Silicon based systems." –Tony

Certainly, maximum efficiency can be worth the cost when space is at a premium – it may become an even easier decision in the future.