IoT & Embedded Technology Blog

Quanta Case versus AMD Underscores Importance of Component/Assembly Testing - Part 2

In the last week’s blog we looked at the semiconductor manufacturing process and the various testing steps that happen as raw silicon is turned into finished devices. In this week's follow up we continue looking at the testing process on the product manufacturing side. Last week we noted that Quanta was manufacturing notebook computers. Because of this, I want to make two observations about the product designs and manufacturing process for notebook computers.

• Notebook computer suppliers are continually trying to make them as thin and lower cost as possible. This means that Quanta might not have been using sockets and could be mounting the AMD/ATI devices directly on the circuit board. This can be a potential problem in some cases where the device was exposed to humidity before being heated as part of the surface mounted device (SMD) process as it can cause device degradation that leads to future failures.

• SMD processes increases costs with respect to failures as repairing a SMD CPU or Graphic component on a computer motherboard with hundreds of densely packed conductors is time consuming, difficult, and the scrap rate of the entire unit can be high.

• As the issue cited in the lawsuit is thermal in nature, it is worth noting that a higher power device such as a CPU or graphics chip often require heat sinks/cooling features to avoid problems. This is another area where manufacturing problems could have been introduced as these devices need to have excellent heat transfer to the cooling feature. Thermal pastes and a process to ensure optimal surface contact between the device and heat sink are needed.

Now, we will look at a few key testing steps on the product manufacturing side.

1.) Incoming Test: This process is considered as being redundant to supplier testing before shipment. Product manufacturers used to commonly test incoming components but, due to cost reduction pressures, that practice is now very uncommon outside the Mil/Aero market. Although it is not likely relevant to the Quanta vs. AMD/ATI case, counterfeiting and other supply chain related cases where lesser specification devices are re-labeled make incoming test more relevant again even in consumer type product manufacture. 

2.) Circuit Board/Module Test: The fully assembled circuit board or module is tested before it is embedded in the final product. Thermal transfer issues can be identified by the use of infrared, optical, and or sensors. Repairs are expensive for problems found here but, it is still far less costly than having the product failing downstream.

3.) Highly Accelerated Life Testing (HALT): This is one last type of testing process that might have mitigated AMD and Quanta’s issue at either the packaged device, module/circuit board or completely assembled product stage. The unit being tested is put through extreme levels of hot and cold cycles while also experiencing other stresses such as vibration and g-forces. In this way, a myriad of potential production issues can be detected before the product ends up in customer hands and/or is in a mission critical role that embedded computers are frequently placed in.

In closing, HALT testing is an almost de-facto step in Military products let alone ones that might be launched into space. In Quanta’s case, you would never do this with all of the units but certainly at least a sample of them. If Quanta did not do this, the brand owner should have.  It does seem like a mystery to me about why this case is happening. It should be interesting to find out where the process became broken or which steps were skipped. If something interesting does come to light in the future we will surely revisit this case.