Tekmos' Blog

Try to count how many times a week you hear that we need to improve the planet. I dare you. For many, the message seems to appear so often, that the impact has morphed into just another day to day annoyance. It has become background noise, or worse, a phrase that provokes disdain. To make matters worse, the message is often conveyed with a sense of guilt. This is probably to get your attention, but does it work? I doubt it. Over time, the constant bombardment makes most numb, irritated or simply immune to the idea all together. Sure, people will nod in agreement. Of course we need to save the planet, protect the environment and not disrupt nature’s balances. But who has the time? And besides, the problem is too big to do anything about anyway. At least, that is what a lot of people think.

At Tekmos, we decided that talk is cheap. Slogans on a website are great, but do they really get a result? Can you see the result? Can you measure it? We didn’t think so. We decided to go beyond the rhetoric. At Tekmos, we decided to roll up our sleeves, take control of what areas we do impact, and make a difference.

That is why we are proud to announce that we have achieved a new Quality Certification. The ISO 14001:2004. Tekmos has created an environmental management system that identifies, measures and continually strives to improve the environment we impact. We did this not just for ourselves, but also for the community we live in, and for everyone we do business with.

“Let’s make our world a better place.” Sure, it is a slogan. But isn’t it nice to know that there are companies that don’t just say it. They do it.

The guts of most durable products today contain a lot of electronics. The external package, whether an iPhone, a TV, or even a washing machine, is usually just the outermost package of multiple layers of packaging. In this article, we will look at innermost package type, the packaging that protects the IC (Integrated Circuit, sometimes called a computer chip.)

Today, silicon chips are made with a very large number of transistors arranged to make digital logic. The transistors are very small, allowing hundreds of thousands, sometimes millions, of transistors, to be made on a thumbnail-sized piece of silicon. A major problem is how to connect signal lines and how to protect the IC from damage. Special electronic packages have been developed to accomplish these tasks.

Advances in chip processing techniques have allowed for larger chips with smaller transistors. As this trend toward higher levels of integration (the inclusion of more circuitry onto a piece of silicon) continues, the number of signal lines has also increased. The package size has grown to accommodate the larger number of signal lines.

The demand for the packages with low pin-count has declined significantly. As the volume falls, the economy of scale goes away. The volume decrease causes the unit cost to increase, putting additional downward pressure on its usage. Then another factor comes into play. The tools to produce any given package type are expensive. A plastic package requires not only a mold and a small piece of metal called a lead frame, it also requires tooling for finishing. As these expensive tools wear out, a choice must be made whether to replace them. The manufacturer must decide if possible future revenue justifies the expenditure for the replacement tooling. Often, it is not practical to continue making some package types.

What do you do if you have a product that has a PCB (Printed Circuit Board) designed for a certain package type? If your PCB has a footprint that exactly matches the placement of connections on a particular package type, how do you proceed if nobody makes a package that fits that footprint? One costly approach is to design a new printed circuit board with a footprint for a similar device in a package that is available. The cost to design the new PCB, debug and test it, and update the documentation can be prohibitive. If the PCB was designed a long time ago, the designers may have moved on leaving incomplete documentation. Often manufacturing does not have a budget for design work. Solutions are even more costly when a new design requires a lot of testing such as for FDA approval.

Every part that Tekmos manufacturers, has to be tested.  The wafer manufacturing process will naturally produce a percentage of non-functional parts, and we must identify them and reject them.  Tekmos uses a combination of inside and outside test resources to test the parts.  Tekmos has experienced sizable growth over the last two years, and as a result, we were finding ourselves limited by our test capacity.  To address this, we decided to buy additional testers to augment the two testers we already had.

Purchasing a tester is a complicated decision.  You need to determine how many pins the tester will need.  Most of our devices have less than 100 pins, though some have 356 pins.  Since tester cost is generally a linear function of pin count, it is important to buy the right amount of pin capacity.  You must also consider the economic tradeoffs of tester speed and vector memory capacity.

After months of internal deliberations, we decided to purchase a new Griffin III tester from HiLevel.  This tester has 128 pins with a 64M vector depth and a 100 MHz clock rate.  This is a significant increase in our capability, since our older testers were limited to 40 MHz and 8M of vector depth.

While we were negotiating over the Griffin II tester, we found another HiLevel on the surplus market.  This one was a model ETS780 tester, with 256 pins and an 8M vector depth.  It is a much older tester, but was a valuable at a reasonable price, so we acquired it as well. 

Along with the testers, we have acquired a new problem.  Each tester has a different mechanical interface.  In the past, we have just built a custom interface for a specific part to connect to a specific tester.  However, this approach has caused capacity problems as our volume has increased.  We frequently find ourselves in a situation where we need two different parts that are only testable on a single tester.  This results in the situation where one tester is running two shifts, while an adjacent tester is standing unused. 

Do you remember seeing the three wise monkey statues, see no evil, speak no evil and hear no evil? Did the idea in an odd way seem to make sense to you? While the origin of the proverb, perhaps Buddhist, perhaps Confucian,  is a bit shrouded in mystery, our Western idea seems to have taken hold. If you refuse to acknowledge something, then how can it hurt you? The problem with this approach is that it surely sometimes can. In our business, there is an invisible force that lurks throughout a test floor. You can’t see it, you can rarely feel it, but it can absolutely destroy our product. The culprit is called electrostatic discharge, or ESD. It is basically a type of contact electrification that takes place when certain materials come into contact with one another. It runs rampant in dry environments, or when any friction is involved. Most people understand it as static electricity. As a kid, (or perhaps even as a mischievous adult,) the action of rubbing your feet across a rug, then surprising a younger sibling or other unsuspecting prey with an electric touch to the ear lobe, always brought sinister delight. Static electricity is extraordinarily fun for kids, but it absolutely has no place in our company.

At Tekmos, we understand that semiconductors are particularly prone to damage, or even failure, sometime many months after contact with ESD. We have taken extra precautions to prevent ESD buildup, and prevent the possibility of it affecting our customer product needs. As part of our Quality system, we have an entire procedure dedicated to ESD control. Our test floor technicians and test operators wear antistatic lab jackets, heel straps and have daily checks on grounding wrist straps. They undergo ESD training with recertification every 12 months. Product is moved on grounded carts to grounded workstations, which are tested with a Surface Resistivity Meter once a quarter. This is four times the standard requirement even by military standards. We also control and monitor the temperature and humidity on our test floor, understanding that even the environment can be a part of ESD creation. From non-conductive floor wax, to antistatic garments, heel straps and wrist straps, daily and quarterly checks with continual education and testing, we do the extra effort necessary to keep from creating the invisible enemy of ESD, and protect our customer’s product. We at Tekmos have our eyes open when it comes to ESD. We have decided not to be the monkey, sitting with its eyes closed. 

About half of our micro shipments are user programmable.  Unfortunately, our different technology means that for the most part, we are not supported by commercial programmers.  And so if the customer is not using something like ISP (In System Programming), then we have to program and label the parts for them.

We can easily program the parts on our automated testers.  Indeed, for larger customers, we include the programming as part of the final test.

The difficult part is in the labels.  We have to have a label and ink that will survive the RoHS surface mount temperature profile of about 250C and the subsequent board cleanings.  And the inexpensive Avery labels won't stand up in that environment.

It turns out that you can buy Kevlar labels that will stand up, and this is what we use.  We also use our barcode printer with the plastic film ink.  The only problem with this is that when we load the labels into the printer, it will waste about two feet of them as it goes through the alignment cycle.  Since that is about $10 worth of labels, this causes me pain, especially since I have to change the labels out when we are done to switch back to regular bar codes.

Eventually, we will replace this with a laser writer.  We have one that we bought at auction, but it is in storage now since we are very short on floor space in our manufacturing area.