Advanced Process Control in Megasonic- Enhanced Pre-Bonding Cleaning

Abstract

The increased complexity of microelectronic and sensor applications that have emerged over the past decade have driven wafer bonding to mature as a production technology for both MEMS and 3D stacked die manufacturing. The use of CMOS device wafers has restricted the types of viable bonding processes to low temperature fusion bonding, adhesive bonding and metal bonding. Due to the specific requirements of CMOS technology the allowed bonding processes had to be adapted in order to fulfill the specific CMOS-compatibility demands. This paper presents a novel single wafer Megasonic based cleaning method with enhanced process control capabilities. This cleaning process is integrated in low temperature fusion bonding process and enables higher bonding yields and a reduction in process fluid usage.