Material improvement for ultrathin-wafer handling in TSV creation and PECVD process

The challenges of 3-D integration are its sophisticated processes that require deposition, etching, bumping, plating, thinning, etc., which drive the need for wafer bonding materials that can sustain the high temperatures and chemically stringent environments found in these processes. This paper presents the development of a novel polymer material to be used as a wafer bonding material suitable for 3-D integration processes. Details of the material properties such as coating and bonding uniformity, thermal stability, chemical resistance, and debonding force are introduced. This paper also discusses the thermal stability of the temporary bonding material during critical backside processes. No degradation of the adhesive interfacial layer has been observed after plasma-enhanced chemical vapor deposition (PECVD) treatment of thin bonded pairs, and full via-last TSV demonstration has been achieved on 50-micron thin bonded pairs using this material.