Characterization of bonding interface prepared by room-temperature Si wafer direct bonding using the surface smoothing effect of a Ne fast atom beam

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• 作者：Yuichi Kurashima ; ^{y-kurashima@aist.go.jp" class="auth_mail} ; Atsuhiko Maeda ; Hideki Takagi
• 关键词：Room-temperature Si wafer direct bonding ; Heterogeneous integration of MEMS ; Surface smoothing ; Ne fast atom beam
• 刊名：Microelectronic Engineering
• 出版年：25 April, 2014
• 年：2014
• 卷：118
• 期：Complete
• 页码：1-5
• 全文大小：2214 K

文摘

We performed room-temperature Si wafer direct bonding by surface activation using a Ne fast atom beam (FAB). The bonding energy between Si wafers prepared by Ne FAB etching is equivalent to that of the bulk materials. We also investigated the surface smoothing effect by Ne FAB etching. A rough Si surface with a surface roughness of 0.40 nm rms was etched by Ne FAB, and its surface roughness was decreased down to 0.17 nm rms. For a Si surface etched at a depth of 30 nm by the Ne FAB, the 1D-PSD (1-dimensional power spectrum density) amplitude was decreased in the range of spatial frequencies >10 渭m^鈭?. Although the Si wafers with surface roughness of 0.4 nm rms could not be bonded, they were successfully bonded after Ne FAB smoothing of etching depths over 5 nm, and a bonding energy equivalent to that of the bulk materials was attained. We succeeded in dramatically decreasing the local strain at the bonding interface by the Ne FAB smoothing effect.