Microstructured anisotropic PDMS sheet for damage-free electrical testing of semiconductor packages

Abstract

The increasing demand for high-density, fine-pitch semiconductor packaging has made reliable electrical probing essential for yield assurance and process monitoring. However, conventional metal-to-metal contact probing often induces severe mechanical damage to fragile microbumps, resulting in degraded electrical reliability and surface wear. In this study, we propose a microanisotropic polydimethylsiloxane (PDMS) sheet (MAPS) that enables damage-free yet electrically stable probing by introducing a compliant and anisotropically conductive interface between the probe and device under test. The MAPS, comprising a PDMS matrix and conductive fillers, was fabricated by a lithography-based soft-molding process that enables precise control of the hole diameter, pitch, and sheet thickness. In addition, no surface damage or electrical aging was observed after 2500 repeated probing cycles, confirming its long-term structural and electrical durability. These findings underscore the scalability and process compatibility of the proposed MAPS architecture for future fine-pitch applications, suggesting its considerable potential as a next-generation high-reliability electrical testing platform for advanced semiconductor packaging.