Coaxial Test Sockets Are In The Critical Path Of Advanced AI/CPU Products

Advanced AI/CPU processors demand extreme high frequency and power performance from SLT and ATE test sockets. These sockets are in the critical path at the end of a very costly silicon fabrication and advanced packaging manufacturing process. Yield loss at this point in the process is catastrophic to the bottom line. We at Modus Test, working in conjunction with our customers, have seen first-hand the major design challenges and changes in test socket technology over the past five years. The modern high-speed/high-power devices necessitated the creation of advanced coaxial test socket designs with excellent high-frequency performance and power delivery. Monitoring and maintaining the key parameters needed to achieve peak performance from these test interconnects is critical to achieving yield entitlement and controlling test cost over time.

Simple continuity, soft bin monitoring and offline socket pin CRES (contact resistance) test are not sufficient for these advanced sockets. Maintaining these sockets requires testing additional parameters. Most advanced sockets now have an embedded coaxial shield to reduce crosstalk and control impedance. This shield needs to have a low resistance connection with a significant majority of the ground pins contacting the shield to perform well. This connection, depending on the design of the socket, can have a limited life span mechanically, and this life span is often not specified by the socket manufacturer. This results in sockets that may be passing specifications from a CRES perspective but failing to yield when used in the test cell. The mechanical characteristics of these designs can also require leakage testing to ensure power and IO pins are not having unwanted leakage to the GND shield over time. This is an extreme challenge when the sockets are now growing to well over 20,000 pins. The probability of an issue increases dramatically at these device scales.

As an industry leader for high-density/high-precision interconnect test, Modus Test has implemented additional test methods beyond CRES on the MPT (Modus Parametric Tester) to ensure test tooling engineers and end users can properly characterize time zero performance, life cycle test, and monitor and maintain these high-performance test sockets over time. With kelvin channel counts of up to 29000 pins and sub-milliohm resolution, MPT is the ideal solution to characterize and maintain modern high pin count advanced test sockets.

Learn more about coaxial socket testing here: https://modustest.org/blog/f/coaxial-socket-testing. Learn more about the Modus Test MPT family of parametric testers here: www.modustest.org.