Tekmos' Blog

Tekmos has introduced a new and exciting development in our production. With the start of several government contracts we have been given the opportunity to expand our product reliability and dive into military level testing. Zachary Kolb was hired and brought onto the Tekmos team to take the lead on our new level of reliability testing.

There are several types of testings we have begun that follow the Department of Defense Test Method Standards for Microcircuits (MIL-STD-883). Some of these methods are not done in house and are sent off to our local reliability counterpart, Criteria Labs who are do tests such as UHAST, Vibration Frequency, and temperature cycle tests.

One of the test methods from the MIL-STD-883 we have now begun to use is placing all production parts under a seal/leak test. Once completed and retuned we re-test these parts on sight for a final inspection before they are sent out the door.

One of the central tests we use in house to measure product reliability is a Tri-temperature parametric testing. When our microcircuit has been released as a production part our AC and DC parameter tests are also released. In turn, we take our device and place it on our DUT board and then put them under temperature using a temptronic thermostream. We then cool the device under test to -55 degrees C and allow our AC and DC parameters/patterns to run through the part.

Once tested we can then see the effects that the lower temperature has on the timing of our devices. With the same thermostream we can test the same device at 125 degrees Celsius. We then compare both temperatures to our room temperature, 25 degrees’ Celsius test. At that point, we are able to identify how various temperatures effect our parametric tests and justify the amount of stress we can have on our products while they are still capable of passing within an acceptable parametric limit. Testing these functional tests at multiple temperatures allows us to conform to MIL-STD-883 for Tri-temp testing.

As a fabless semiconductor company, Tekmos outsources wafer fabrication and device assembly. The decision to outsource testing is more complicated. As a basic philosophy, Tekmos would prefer to do all testing in-house. This is driven by a need to control a major component of the manufacturing and to insure that our customer’s priorities are being met. But we occasionally get either product types or package types which we cannot do in-house, and so we outsource the testing of those parts. The deciding factors are a combination of pin-count and package type.

Our largest tester has 320 data channels and can support parts up to about 400 pins. If the pin count is higher than that, we will have to either design a custom tester, or outsource testing.

The package type and its associated volume is another factor in deciding to outsource. Any part can be manually tested, but manual testing is slow, and so we only use it for low volume parts. Higher volume parts have a lower cost, and are more sensitive to the test cost. Tekmos has a number of handlers, and tape and reel machines, but we don’t have the capability for tray-fed tape and reel. Or at least we didn’t until last month.

In the last year, we have seen a large increase in our consumer products volume. And since most consumer ICs are QFN devices that are sold in a Tape & Reel format, we have needed to increase our T&R capacity. Our current machines are tube fed, but we needed to get one that was tray fed to handle the QFN packages. So, we purchased a second Tape and Reel machine.

Our new machine has a capacity of about 2000 units per hour, which translates to about 15K units per day with a single shift of operation. It also has an optical inspection capability, that checks to make sure that the package is orientated correctly in the tape before it is sealed.