ATE workshop weighs functional test

Functional test will remain necessary for analog test.

By Rick Nelson, Editor in Chief -- Test & Measurement World, 9/1/2010 12:00:00 AM

Email

The evolutionary path of semiconductor ATE (automated test equipment) seemed clear at Semicon West, held July 13–15 in San Francisco. Gone are the expensive, big-iron functional testers of yesterday, to be replaced by low-cost systems like the V101 (figure), which Verigy displayed at its booth. In addition, Advantest at the show touted the delivery of its milestone 1000th T2000 SOC test system, which went to Xilinx at the FPGA maker's San Jose, CA, facility. The T2000 was developed to help Intel and other IC vendors control test costs though the support of structural test techniques and multisite capability.

The V101 low-cost SOC test system includes new mixed-signal testing capabilities. Courtesy of Verigy.

Yet, despite the evidence on the show floor, the book isn't closed on functional test. Functional test will remain necessary for analog test, which is not extensively supported by DFT (design for test) efforts, and the V101 and T2000 both offer mixed-signal options. But participants at the IEEE ATE Vision 2020 workshop, held July 15 in conjunction with Semicon West, also suggested other situations in which functional test has a future.

Han Ta of Cisco Systems, for example, cited unmodeled defects, noise, crosstalk, and lack of margin as issues that might require a functional-test approach rather than a DFT-based approach. He suggested a "functional built-in self-test" approach that can support tests across asynchronous domains.

Presenter Ken Lanier of Teradyne conceded that DFT has done a lot—improving fault coverage, reducing test times, and speeding time to market, for instance. But, he said, scan test is a divide-and-conquer approach that might not ensure that all parts of an increasingly complex SOC (comprising CPU, MPEG decoder, graphics engine, memory, and media interfaces, for example) work well together. That, he said, might require protocol-aware functional test.

Complicating the coming test challenges will be the emergence of 3-D devices with through-silicon vias (Ref. 1), which will present challenges of physical access, regardless of whether the test signals applied are structural or functional. Marc Loranger of FormFactor discussed the challenges and advantages of direct-on-TSV microbump probing, which can detect bad TSVs and TSV formation defects. Stojan Kanev of Cascade Microtech described both contact and noncontact test methods, noting that design for testability will be key for 3-D probing success.

Test is likely to see rapid evolution as ATE makers and their customers contend with 3-D and other complex devices. The Vision 2020 workshop can help you keep up. Visit www.atevision.com for news of future events.

To read past "Tech Trends" columns, go to www.tmworld.com/techtrends.

REFERENCE
1. Nelson, Rick, "The time is now for 3-D stacked die," EDN, July 15, 2010. p. 9.
www.edn.com.

 

Contactors suit ICs with differential signals Multitest now offers differential contactors that are custom-tailored for semiconductor test applications. Using 3-D electromagnetic simulation software and lab-correlated data, the company optimizes contactor materials and probes for specific impedances, matching the characteristic impedance of the board and contactor as closely as possible to that of the tester electronics and the DUT (device under test). www.multitest.com. JTAG controller for PCI Express Part of the ScanBooster line of JTAG/boundary-scan controllers from Goepel Electronic, the ScanBooster/PCIe-DT is compliant with the PCI Express bus specification. It can be used to perform JTAG/boundary-scan tests, emulation tests, and in-system programming of PLDs, FPGAs, and flash serial EEPROMs. The PCIe-DT comprises a PCI Express plug-in card coupled with an external TAP (Test Access Port) transceiver. www.goepel.com. Pickering debuts PXI supply Pickering Interfaces has introduced the 41-743, a single-channel power supply able to provide 2 A up to 20 V and 0.8 A up to 48 V. The supply includes remote-sense connections as well as a voltage monitor and programmable current limit. The module supports both PXI triggering and external triggering. www.pickeringtest.com.