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Shorts-open test application illustrates switch-matrix choices

Dec. 18, 2015

Shorts and opens testing can evaluate a semiconductor package before functional test, and the technique can also be used for failure analysis. According to Pickering Interfaces, one or more source-measure units (PXI or bench-top) and one or more switch matrices are essential for such tests. For short-opens test only, the matrix should support two-wire (Nx2) measurements. For applications requiring low-resistance measurements or precision I/V characterization, the matrix should support four-wire (Nx4), or Kelvin, measurements to compensate for switch and cable-path resistances.

Pickering also outlines the relay types available for matrices for such applications: hermetically sealed reed relays are fast and reliable but are higher cost and offer lower power-switching capacity compared with other types; electromechanical relays (EMRs) have higher switching capacities and lower cost but are slower and have shorter lives; and solid-state relays offer virtually unlimited life and are fast (with no switch bounce) but have bandwidth, leakage, resistance, and voltage limitations.

In addition, customers can select a custom design or one based on VXI, PXI or PXI Express, or LXI platforms.

Pickering provides a specific example of a shorts-open test implementation with regards to Amkor, the contract semiconductor assembly and test company. Amkor’s Korean division required a 3,072×4 matrix switch configuration able to perform four-wire measurements (for I/V characterization) as well as two-wire measurements. Amkor chose three Pickering LXI high-density switch modules that employ electromagnetic relays and allow up to 1,027 simultaneously closed crosspoints. System integrator Testmation put the system together. Visit Pickering Interfaces for more on this project.

About the Author

Rick Nelson | Contributing Editor

Rick is currently Contributing Technical Editor. He was Executive Editor for EE in 2011-2018. Previously he served on several publications, including EDN and Vision Systems Design, and has received awards for signed editorials from the American Society of Business Publication Editors. He began as a design engineer at General Electric and Litton Industries and earned a BSEE degree from Penn State.

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