SOI像素探测器的COB组装工艺初步研究

A Preliminary Study of COB Assembly Technology for SOI Pixel Detector

从子板PCB设计、芯片粘接、优化引线键合参数方面对SOI像素探测器的COB组装工艺做了初步研究。基板焊盘表面处理选用了电镀化学镍钯金的工艺,并对焊盘排布方式做了改进;芯片粘接选用了导电环氧树脂胶,探讨了水平定位误差和垂直定位误差对键合的影响及处理方法;通过反复试验和不断优化得出一套引线键合优化参数。对子板模块性能测试表明:其噪声和漏电流水平均保持在合理范围。COB组装技术可为后续的硅像素探测器芯片拼接提供技术支撑。

This article introduces a COB assembly process for the SOI pixel detectors, including the design of PCB boards, die attachment, and optimization of wire bonding parameters. The bonding pads were treated by depositing additional layers of nickel, palladium and gold. The layout of pads on PCB was also improved to fa- cilitate the wire bonding operation. Conductive epoxy was used to glue the SOI chip and PCB substrate togeth- er. A short discussion on the misalignment of die attachment is given. A set of wire bonding parameters was ob- tained through careful tuning. A performance measurement on the COB - assembled board showed that its noise and leakage are well - controlled. This technology provided a solid basis for further multi - chip assembly.