Study on Fabrication Method for Narrow Pitch Beams on Silicon Probe

Abstract

A fabrication method of silicon probe has been developed for wafer-level-testing of semiconductor with narrow-pitch electrodes. The silicon probe consists of probe-tips, beams and three-dimensional wirings. The probe-tips and beams are fabricated by anisotropic etching with KOH aqueous solution. The beams were conventionally fabricated with etching a back side of substrate after etching a top side. However, after the back side etching step, the defects were observed on the back side of beams. We clarified that the defects were caused by etching that proceeds from defects in the silicon oxide layer on V-grooves with a scanning electron microscopy (SEM). Thus, we propose an improving fabrication method, which the beams are formed by etching from the both sides of silicon substrate. With this method, narrow-pitch beams on a silicon probe can be fabricated without defects.