Challenges in packaging of IR detectors - technology of elastic electrical connections

[摘要] This paper describes the study on flexible connections application in IR detector package. Such a connection is used between two modules in single package. One module is IR detector operating at -73 °C, other is electronic controlling circuit operating at room temperature. Flexible electrical connection must provide good electrical parameters in both DC and RF regime as well as poor thermal conductivity. 35 μm epoxy-phenolic foil with 5 μm Ni film and special RF compatible Ground-Signal-Ground geometry was successfully applied as connection. Low eutectic temperature InSn solder was used for soldering flexible connection to both IR detector and electronic circuit. Two types of soldering processes were investigated: bump and lap type. Flexible connection was tested for DC operation with long term stability test and RF parameters were determined. Authors found that both joining techniques are suitable for application in IR photodetector devices. However lap type joint is easier to apply in technological process, therefore it will be applied in final assembly.

[发布机构] Warsaw University of Technology, Institute of Microelectronics and Optoelectronics, Nowowiejska 15/19, Warszawa; 00-665, Poland^1

[关键词] Electrical connection;Electrical parameter;Eutectic temperature;Flexible connections;Ground signal grounds;Joining techniques;Long-term stability test;Technological process