封装腔体内氢气含量控制

目前,对密封腔体内的水汽、二氧化碳、氧气含量的研究比较多,内部水汽含量控制在≤5 000 ppm、氧气控制在≤2 000 ppm、二氧化碳控制在≤4 000 ppm、氦气控制在≤1 000 ppm的密封工艺技术已解决9],氢气含量控制的研究则未见报道。对于一些气密性要求高的封装应用领域,还需要控制氢气含量,如MEMS、GaAs电路等。分析了平行缝焊、Au80Sn20合金封帽的导电胶、合金烧结的器件的内部氢气含量,并分析了125℃168 h和125℃1 000 h贮存前后氢气含量的变化情况;在试验的基础上,提出了氢气的主要来源和针对性的工艺措施,并取得了期望的结果：密封器件经过125℃、1 000 h贮存后的氢气含量也能控制在≤4 000 ppm。

Control of Internal Hydrogen Content for Hermetic Package

There have been a lot of researches on the vapor,carbon dioxide and oxygen contents in the cavity of a hermetic package.At present,the issues about the control of the internal vapor contents less than 5 000 ppm,oxygen contents less than 2 000 ppm,carbon dioxide contents less than 4 000 ppm and helium contents less than 1 000 ppm have been solved.But the studies about the control of hydrogen contents have not been reported.In some packaging applications such as MEMS and GaAs circuitry with high level of hermetic requirements,the control of hydrogen contents is required.In this article,the internal hydrogen contents of the devices with conductive epoxy or sintered alloy for chip loading and parallel seam sealing or Au80Sn20 alloy sealing for hermetic sealing are studied.The changes of hydrogen contents before and after being stored for 168 hours and 1 000 hours at 125 ℃ are analyzed.Based on the experiments,the main sources of hydrogen and the corresponding technical measures are presented,and the desired results are obtained,that is the hydrogen contents of the hermetic devices can be controlled to less than 4 000 ppm after being stored for 1 000 hours at 125 ℃.