Abstract:
An electron bombardment active pixel sensor (EBAPS) is a hybrid optoelectronic imaging device that combines vacuum and solid-state devices. Its vacuum sealing requires high-temperature baking and degassing processes. During development, a key challenge is addressing the issue of the epoxy adhesive used to bond the silicon-based chip in the complementary metal oxide semiconductor
(CMOS) image sensor to the ceramic base, which may decompose at high temperatures, causing the CMOS chip to detach and fail to capture images. To address this, the project team used three types of solder alloys with similar melting points: Au
88Ge
12, Pb
92.5In
5Ag
2.5, and Zn-Al-Ag-Cu to bond the metallized CMOS silicon-based chip to the ceramic base. The cross-sections of the CMOS image sensors soldered with these three types of solders were tested and characterized using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) to analyze the performance of the solder joints. The results indicated that the CMOS image sensor soldered with Au
88Ge
12 achieved stable and reliable connection performance.