平板电封装工程中的凸点实现及其在紫外焦平面成像阵列中的应用

紫外焦平面成像系统主要用以观测日光下高压输电系统的电晕放电现象。焦平面成像系统主要由信号采集系统、控制系统、信号处理系统和信号存储系统构成,再加上后端的显示器件,就可以完成视频信号的采集、处理、运算、传输和显示等功能。本文在设计紫外焦平面成像系统的时候,参考了发展相对成熟的非制冷型红外焦平面成像系统的技术结构。为了将采集图像的焦平面探测阵列与后端的电路系统连接起来,关键技术是以凸点制作为基础的倒装焊技术。由于焦平面探测阵列的引出点阵的密集性,最好采用性能指标较好的光刻结合电镀的倒装焊工艺。为了保证焊接过程不影响紫外探测元件的性能,凸点材料选择了焊点较低的软金属In,并介绍了这种焊点的制作工艺。

Bumping Technology in Flat Electric Packaging Project and Its Application in Ultraviolet Imaging Focal Plane Arrays

A ultraviolet(UV)focal plane array(FPA)imaging system is mainly used to observe the corona of a high voltage transmission system in daylight.A FPA imaging system is mainly composed of a signal acquisition system,a control system,a signal proceasing system and a signal storage system.If a display is added at its back end,the imaging system can has the functions of acquisition,processing, operation,transmission and display of video signals.In this paper,the relatively mature technologies of uncooled infrared FPA imaging systems are used for reference when a UV FPA imaging system is designed. To connect the FPA for acquisiting images to the circuit at the back end,it is critical to use the bumps based on flip-chip bonding.Because of the density of the lattice of a FPA,it is preferred to use the flip-chip bonding technology which combines lithography with electroplating and has a better performance.In,a soft metal which has a lower melting point is selected as the bump material.Finally, the jointing technology of this solder is presented.