低温Al-Al熱圧着ウェハレベル真空封止接合における薄膜Sn層の役割

カテゴリ: 論文誌(論文単位)

グループ名: 【E】センサ・マイクロマシン部門

発行日: 2017/12/01

タイトル(英語): Role of Thin Sn Layer for Low Temperature Al-Al Thermo-compression Bonding of Wafer-level Hermetic Sealing

著者名: 佐藤　史朗（東北大学マイクロシステム融合研究開発センター），福士　秀幸（東北大学マイクロシステム融合研究開発センター），江刺　正喜（東北大学マイクロシステム融合研究開発センター），田中　秀治（東北大学マイクロシステム融合研究開発センター／東北大学大学院工学研究科）

著者名(英語): Shiro Satoh (Micro System Integration Center, Tohoku University), Hideyuki Fukushi (Micro System Integration Center, Tohoku University), Masayoshi Esashi (Micro System Integration Center, Tohoku University), Shuji Tanaka (Micro System Integration Center, Tohoku University/Graduate School of Engineering, Tohoku University)

キーワード: 熱圧着接合，真空封止，低温接合，アルミニウム（Al），錫（Sn），MEMSパッケージング　　thermo-compression bonding，vacuum seal，low temperature bonding，Aluminum (Al)，Tin (Sn)，MEMS packaging

要約(英語): This paper reports low temperature hermetic wafer bonding using Al/Sn/Al/Sn/Al as a bonding layer. The Al surface of the bonding layer was oxidized in air, but hermetic sealing was demonstrated without surface treatment at 370～390℃, which was lower than the maximum temperature of CMOS backend process (400℃). For the successfully sealed samples, the bonding layer was considerably compressed and squeezed, and the remaining thickness was only <16% of the initial one, i.e. the reduction rate was >84%. On the other hand, the samples without Sn layers inserted, i.e. using a pure Al bonding layer, were not hermetically sealed at similar temperatures, showing the reduction rate smaller than 70%. A clear correlation between the reduction rate and the yield of hermetic sealing was observed. Taking account of analytical results and Al-Sn phase diagram, it is suggested that Al-Sn liquid phase in Al grain boundaries enhances the grain slip deformation of the bonding layer and fractionates the surface Al oxide layer during the bonding process. The function of Sn for Al-Al bonding suggested in this paper is useful for wafer-level hermetic MEMS packaging at low temperature.

本誌: 電気学会論文誌E（センサ・マイクロマシン部門誌） Vol.137 No.12 （2017）

本誌掲載ページ: 432-437 p

原稿種別: 論文／日本語

電子版へのリンク: https://www.jstage.jst.go.jp/article/ieejsmas/137/12/137_432/_article/-char/ja/