Integration and manufacturing aspects of moving from WaferBOND HT-10.10 to ZoneBOND material in temporary wafer bonding and debonding for 3D applications

Abstract

Among the technological developments pushed by the emergence of 3D Stacked IC technologies, temporary wafer bonding has become a key element in device processing over the past years. Today, although solutions for wafer support systems have made great progress in terms of process performance, thin wafer debonding and handling remains extremely challenging. Our motivation to move away from thermoplastic high temperature melt debonding materials to room temperature debondable materials is clearly exposed in this paper: we describe the process integration and manufacturing aspects of the Brewer Science <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> ZoneBOND <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> temporary bonding process, as a one-to-one alternative to the Brewer Science <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> WaferBOND <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> HT-10.10 slide debonding material. Process issues related to the material integration into complex 3D flows as well as key learnings are described in details. One important modification that was required is related to the edge-trimming process that is typically performed on the active device wafer prior to bonding and grinding. The ZoneBOND <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> material was found not to be compatible with this process, resulting in permanent defects and damages during grinding. To resolve this issue, the process flow was modified to an edge-trimming after wafer bonding approach. Finally, the room temperature debonding process is fully described.