Effect of Formic Acid Vapor In Situ Treatment Process on Cu Low-Temperature Bonding
Effect of Formic Acid Vapor In Situ Treatment Process on Cu Low-Temperature Bonding
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DOI：
10.1109/tcpmt.2014.2315761
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发表时间：
2014-04
期刊：
影响因子：
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通讯作者：
Wenhua Yang;M. Akaike;T. Suga
中科院分区：
文献类型：
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作者：
Wenhua Yang;M. Akaike;T. Suga
研究了甲酸蒸汽原位处理低温Cu/Cu直接键合技术。研究了甲酸蒸气处理条件对Cu表面和键合的影响。在150°C和200°C的温度下，采用甲酸蒸汽原位处理对Cu表面氧化物进行还原。温度越高，处理时间越长，表面还原效果越好。经甲酸初始处理后，化学机械抛光铜膜出现了晶界腐蚀现象。而长时间甲酸蒸气处理对铜表面粗糙度的影响最小。在200℃以下的温度下，采用甲酸蒸汽原位处理，在N2气氛中实现了Cu膜/Cu膜的直接键合。对于较低的处理温度，需要较长的处理时间才能达到良好的粘合。当Cu表面在200℃下处理10 min时，其结合强度约为9.0 MPa。
Low-temperature Cu/Cu direct bonding technology using formic acid vapor in situ treatment was developed. Effect of formic acid vapor treatment conditions on Cu surface and bonding was studied. Cu surface oxide was reduced using formic acid vapor in situ treatment at 150 and 200°C, respectively. With higher temperature and longer treatment time, surface reduction is more effective. Grain boundary etching was found on chemical mechanical polished Cu film after initial treatment by formic acid. However, Cu surface roughness is minimally influenced by long-time formic acid vapor treatment. Cu film/Cu film direct bonding was realized in N2 atmosphere with formic acid vapor in situ treatment under temperature below 200°C. For lower treatment temperature, longer treatment time is required to achieve good bonding. The bonding strength is about 9.0 MPa when Cu surface is treated at 200°C for 10 min.