Development of a Temporary Bonding Tape Having over 300 degC Thermal Resistance for Cu-Cu Direct Bonding

Hybrid bonding (or Cu-Cu direct bonding) is one of the most important interconnect technologies for next generation 3D-packaging. Because it is an enabler for fine pad pitch interconnection between chips such as <; 5 μm and for lower conductivity at joints. However it needs very high temperature such as 300-350 degC for Cu diffusion to perform robust joint. Therefore, not only process equipments but also process materials are required to have thermal resistance during the high temperature bonding process. In this paper, a Temporary Bonding De-Bonding (TBDB) tape having over 300 degC thermal resistance is introduced for hybrid bonding. The adhesive is composed of a resin which has higher thermal resistance than conventional resins so that the tape can support thin wafer on glass carrier without delamination at the high temperature. Also it can be removed without any residue on the wafer after the thermal process. Many studies have been done to lower bonding temperature for metal diffusion of hybrid bonding, but it is indicated that over 300 degC for bonding process would be available bonding condition by using this TBDB tape for 3DIC applications.