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.

Over the summer we rolled out an Enterprise Resource Planning (ERP) system. The aim of this system is to automate many of the day to day tasks we deal with at a company level and reduce the chance of miscommunication between employees.

The system we use is broken down into “Projects” and “Issues”. A Project is what the bigger picture would be, for example, travelers, new engineering test releases, sales orders, etc. An Issue is a single instance of the project, such as a single traveler for a specific part, a new test for a part, or a sales order. Although our ERP system is still a work in progress, we have currently moved our traveler system for testing parts to a digital system and as a result have improved productivity by streamlining the process.

To accomplish the traveler system, multiple databases have been created that contain our commonly used setups for hardware, software, and testing. This information is then automatically populated into the travelers. This allows the test engineers to speed up the initial stages by having all the information they need available to them instead of having to ask the engineers for the appropriate setup information. We have also integrated several tablets into the system to allow for the digital traveler to travel (move) with the parts from station to station, in a way similar to how the paper travelers moved with the parts.

The databases from the travelers play into the engineering test releases as well. Prior to this system there was never a clear database that was updated with all the approved hardware configurations. When the engineers completed tests, these tests were released to their standards without a universal internal standard. To help with the population of the database another project was created to keep track of these tests.

The sales order Project prompts whomever is processing the customer order for the basic information about the order and then sends this information to the next person to work on the order. After the information is entered into the system, an automatic email is generated and sent to the customer informing them that their inquiry has been received and an update with specifics about their order being processed will be sent soon. With this system all of our sales orders are presented in one place with the date they were received and entered, as well as reminders being sent to key people to follow up on the progress of these orders if they aren’t handled in a timely manner.

Tekmos offers Burn-In and Reliability Testing services.  The requirements can vary from part to part, and Tekmos can customize these services to meet your exact needs.

Burn-in

The failure rate of integrated circuits over time follows what is called the "bathtub" curve.  There is a high rate of infant mortality initial failures.  Then the failure rate drops, only to increase at the end of life due to wear out failures.  The reliability of a part can be enhanced by providing a burn-in at elevated temperatures prior to usage.  This burn-in is typically somewhere from 40 to 160 hours in length, and is done at a temperature of between 70ºC and 125ºC.  It is important that the parts be exercised during this burn-in.  It is also good to monitor the part performance during burning, so that the time point of failures can be detected.  That data can be used to set the optimum burn-in length.

One of the major costs of a burn-in is the boards used for the burn-in.  This is a tradeoff between the cost of the sockets on the boards, the number of boards needed, and the total number of parts to be burned in.  Major manufacturers with very high volumes will invest in high quality sockets that will cost from $50 to $100 per chip.  This socket cost adds up quickly.

In addition to the oven capacity, Tekmos also has in-house design and layout capability for both the burn-in boards and driver boards (if needed).

Reliability Testing 

There are several over-lapping reliability testing specifications.  Specifically, these are the JESD47I, the AEC-Q100, and the military Mil Spec 883.  These require subjecting several lots to stresses, and then looking for failures.  Some tests are for the die, and other tests check the packages.  Because of the standardization of the packages, the die tests are the most important.  And the main die test is the HTOL, or High Temperature Operating Life.  In this test, the parts are typically operated at 125ºC for 1000 hours.  If the parts cannot be tested in the oven, the parts will be periodically pulled from the oven, tested, and re-inserted back into the oven.  Common read points are at 48, 96, 168, 250, 500, and 1000 hours. 

Tekmos offers test and characterization services. As a fabless semiconductor company, Tekmos has an internal test facility, with testers ranging up to 320 pins in size. We offer access to these facilities and the engineers that run them.

Verification and Debug of ASICs 

Some customers have developed an ASIC, but lack the facilities to completely test it, or to debug it if there is a problem.  Our testers provide the means to verify the ASIC, and to debug it.  Also, our testers can be remotely accessed, allowing the customer engineer to exercise their part from the comfort of their own office. 

Verification of Brokered Parts 

Brokers have become very efficient in obtaining mature parts.  But there is always the question of if the parts are correctly marked,  and will they perform to specification.  Re-testing the parts is the best way to resolve those questions.

Test Program Creation 

Customers do not always have a test program for their parts.  In those cases, we can create one from scratch.  Starting from either design files or a data sheet, our engineers can write patterns that functionally exercise the parts.   

Product Characterization 

The question for all new parts is does the part meet all specifications over the temperature and voltage limits?  And the only way to find out is to measure it.  Tekmos can take your part, and measure the functionality, DC specifications, and AC specifications over the desired temperature range.  Then we consolidate the data into a report, that shows how well the new part works as compared to the specifications.  This service is useful for both new designs and to evaluate existing designs. 

Sometimes, a project needs additional engineering resources.  When that happens, Tekmos design engineers are available to help.

Digital ASIC Design

Working from your specifications, Tekmos can create digital designs and layouts in your preferred process technology.  We can also assist with IP selection and interfacing.

Mixed Signal ASIC Design

Not all designs are digital.  Tekmos can design the analog portions, and provide the design in either schematic form or a GDS layout in the process technology of your choice.

FPGA Design

Our designs are not just for ASICs.  We can also develop FPGA based designs, in any of the FPGA families.  Internally, it is our standard practice to implement our processors in an FPGA before we commit to silicon.  This has given us a great deal of experience in working within the FPGA environment.

IP Design 

Sometimes a design needs an IP block.  These are usually a specific peripheral to a processor, or a communications interface.  IP locks serve as an efficient way of partitioning a design so that multiple designers can work on the same project.  Many IP blocks can be purchased, while others need to be designed to meet a customer's specific requirements.