Thursday, July 3rd, 2008
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Posted by Amanda M. Hartnett
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Click on the Table of Scpecialty Alloys link on the Indium homepage to view physical properties of more than 200 alloys used for their thermal and mechanical properties.
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When I need any information on a direct attach solder thermal interface material, my first line of defense is my solder alloy directory, also known as the "Table of Specialty Alloys and Solders".
The information in this literature is available to you as well on Indium’s website. It contains the most popular as well as the unusually-requested solders along with many of their physical properties. Over 200 solder alloys are listed (all of which could be used as a thermal interface material) and at a minimum, you will find the melting temperatures of these materials. For many of the materials, thermal, electrical, and physical properties of each alloy are also listed.
Posted yesterday by Amanda M. Hartnett |
Wednesday, July 2nd, 2008
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Posted by Amanda M. Hartnett
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Design Ideas behind Compressible Metal Interface Materials
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As a Thermal Interface materials supplier, we are always looking for the next best material we can offer the market which will really fill a need. Over a year ago now Indium’s Bob Jarrett came up with a new product which would meet the consumer need for a low pressure compressible metal thermal interface material. This was the advent of the SMA-TIM. The idea hit him when he realized that pure indium held the potential to be a great compressible material. It just needed some minor mechanical alterations to make it more compressible under lower loads.
Previous to this, many of our customers were filling this need using flat indium foils. But under 100PSI, pure indium just wasn’t cutting it in performance. Since the conception of this new material we have been able to aid many of these customers by providing them with a perfectly suited material which would outperform flat indium alone.
Posted 2 days ago by Amanda M. Hartnett |
Tuesday, July 1st, 2008
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Posted by Amanda M. Hartnett
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Metal Phase Change Materails Dispensed to mold a thermal interface gap, determining physical characteristics needed for a Thermal Interface Material
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Looking for ways to troubleshoot or optimize your Thermal Interface materials? One method which we have contrived to determine the performance of your thermal stack-up excluding the thermal interface material is to use a liquid metal. This is a topic I have discussed at multiple conferences, but will discuss in-depth in a later posting.
Another method that can be used involves placing a phase change metal at the thermal interface to make a mold of the Tthermal interface material gap. Some metal thermal interface materials melt at a low enough temperature to melt during chip operation or under mild heat. At room temperature however, they re-solidify, taking a mold of the thermal interface material gap. By disassembling your thermal stack-up with the phase-change metal, you can view any non-planarity of substrates or surface roughness through inspection of the metal thermal interface material. It is unlikely that the interface material will completely squeeze-out or appear with a smooth mirror-like finish because no machined parts are perfect. This method will demonstrate just how far off perfect your material design has come.
Posted 3 days ago by Amanda M. Hartnett |
Monday, June 30th, 2008
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Posted by Amanda M. Hartnett
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Liquid Metal shear and mechanical properties (viscosity) demonstrated through basic stencil printing.
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Many of my customers are now getting their minds wrapped around the idea of using liquid metals as TIMs. Until they actually have the personal experience of working with it however, they don’t fully grasp what it is like to handle.
The closest thing I am able to compare the indium-gallium liquid metals to is the consistency of mercury. Most of us have had the luxury (although an unfortunate health hazard) to play with mercury broken out of a thermometer as a child. The liquid metals used as thermal interface materials (TIMs) are quite similar in their tendency to coalesce into little balls due to surface tension. Additionally, the viscosity of liquid metal TIMs are nearly identical to mercury.
Viscosity, or the ability to withstand shear, is a very telling property of materials. It is perhaps the most significant property depending on the method of handling and application used for the material. The viscosity of mercury is 1.53 x 10-3 Pa*s and the liquid metals of the indium gallium system are almost identical.
Posted 4 days ago by Amanda M. Hartnett |
Wednesday, June 25th, 2008
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Posted by Amanda M. Hartnett
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Summer Heat Causes Electronics to Overheat If They are not Designed and Handled for the Elements
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Summer is here along with the heat waves that come with it. I am personally prepared with central air and barely-there clothing for when the heat gets most intense; but are my electronic gadgets as prepared?
According to the Office of Zen and Computing, electronic gadgets are not as prepared as one might hope. Although I’m in the business of preventing gadget overheating as a supplier of cooling materials, I realize that often cooling is considered as an afterthought in electronics packaging. Because of that, I recommend following the Office Zen’s recommendations regarding electronic handling in the summer heat.
On their blog entry, they give some great tips such as:
1. Don’t Stack Electronics
“You should never stack electronic devices directly on top of each other. Is your XBox sitting on top of your DVR, which is sitting on top of your DVD player? Go do something about that, right now. Electronic devices get hot enough on their own. When they’re stacked on top of each other, they produce and conduct even higher temperatures.”
2. Position Electronics Away from Heat
“When it comes to where you store your electronics, use common sense. Keep them out of direct sunlight, and if it’s possible, in the path of a fan or air conditioner. Hot air rises, so store things on the basement or ground level of your home.”
3. In Case of Emergency, Shut Down
“If one of your gadgets begins to overheat and malfunction during the hot summer months, shut it down and disconnect it’s power supply. Let it sit and cool down until the casing is no longer hot to the touch, and then try to use it again. Make sure it’s not stacked with any other devices, and keep the area clear to allow for proper airflow.”
I believe each of these tips to be true and suggest that you follow them as a mode of protection for your beloved electronic gadgets.
Posted June 25th, 2008 by Amanda M. Hartnett |
Tuesday, June 24th, 2008
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Posted by Amanda M. Hartnett
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Mike Fenners article of soldering in automotive devices can be found in the June edition of OnBoard Technology
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My Co-Worker, Mike Fenner wrote an article in the June 2008 issue of OnBoard Technology (A Great Resource of SMT Electronics Literature). His article, “Soldering: Is the Automotive Assembler Really Different?” asks the question of whether electronics used in auto applications are handled differently than other applications.
This got me wondering, “Is there also a difference in thermal design between various end product types?” I have to say that the answer, like it or not, is yes, at least with regard to the TIM material. The applications I see most commonly are very critical ones-military, medical, etc. This is likely due to the reliability my products can handle, but there is certainly still a difference. The auto devices require very thorough testing before any material is specified into the device while less critical applications, require less-strenuous life testing, which a wider variety of TIM materials are capable of passing.
Posted June 24th, 2008 by Amanda M. Hartnett |
Wednesday, June 18th, 2008
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Posted by Amanda M. Hartnett
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StratEdge semiconductor package optimizes thermal performance using gold-based solder seal.
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I was pleasantly surprised to see in the Summer 2008 edition of Thermal News, a thermally enhanced package was highlighted for its design by StratEdge. StratEdge, with its forward-looking design has used the materials I have recommended for years to seal their semiconductor packages. (Click here to read the full article).
I have seen semiconductor packages generate exorbitant amount of heat, so much so that epoxies and even traditional solder seals cannot withstand the heat without jeopardizing package reliability. The exception to this are the gold-based solder alloys which withstand temperatures up to 360ºC and have great thermal conduction properties.
Stratedge has implemented these materials and is now reaping the benefits through their package performance. If you are interested in evaluating these materials or have questions regarding them, please feel free to contact me!
Posted June 18th, 2008 by Amanda M. Hartnett |
Tuesday, June 17th, 2008
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Posted by Amanda M. Hartnett
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Now I know you may be wondering why I have been slacking with my blog postings to the extent that you haven’t seen anything new in weeks, but I assure you that I will return to my regimented posting schedule right away.
I have just returned following my honeymoon vacation in Ireland and England. I had a fabulous time as you can see in this picture. I am visible here with my husband, Andy, where we took a jaunting ride through the city of Killarney, Ireland.
Posted June 17th, 2008 by Amanda M. Hartnett |
Thursday, May 29th, 2008
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Posted by Amanda M. Hartnett
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The Book Mobile delivers books of all types to anxiously awaiting students. They were not the ones who delivered my new indium alloys phase diagram book, but I was equally excited to receive it.
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Just like the yearly event which occurred in my grade school, new books were delivered to my door in their shiny cellophane wrapping just waiting for the unearthing of new data. In my book order was a new revision of a fantastic book I use on a regular basis and believe is deserving of recognition.
This book, called Phase Diagrams of Indium Alloys by Charles White and Hiroaki Okamoto, is something any high tech indium material user should have handy. The latest revision, number 8, was just printed and I have a crisp new copy! I encourage you to get one too if you don’t already have one. A copy can be purchased through ASM International.
The book details the properties of nearly 100 binary and ternary systems, all indium contained. Each system is outlined to include a phase diagram and crystal structure data. I used this information just today to identify expected melting temperatures and homogeneity of an indium alloy which I was not familiar with already.
Image Courtesy of jamd.com
Posted May 29th, 2008 by Amanda M. Hartnett |
Wednesday, May 28th, 2008
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Posted by Amanda M. Hartnett
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The Mosfet Evolution has brought us today to these tiny, hot TSOP-6 components. Image from eettaiwan.com
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In this month’s edition of SMT magazine, Craig Hunter wrote a fantastic article about Mosfets and the transition they have made over time. These components have transitioned both in size and in thermal design, today requiring top notch cooling solutions.
To read the full article on Mosfets and their evolution to smaller and hotter chips requiring reliable cooling solutions and materials, go to the May edition of SMT magazine.
Posted May 28th, 2008 by Amanda M. Hartnett |
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