An Infrared Laser Temporary Bonding Material Used for Device Wafer Thinning and Completion of Backside Processing Technology

Temporary bonding/de-bonding cooperation is the core technology of thin wafer holding. Through the innovative application of temporary bonding materials, the device wafer is fixed on the carrier wafer to provide sufficient mechanical support for the ultra-thin device wafer to ensure The device wafer can smoothly and safely complete subsequent processes, such as photolithography, etching, passivation, sputtering, electroplating, and reflow soldering. With the rapid development of advanced packaging processes, temporary bonding/de-bonding technology has been vigorously developed and widely used in the field of wafer-level packaging (WLP), such as PoP stack packaging, fan-out packaging, eWLB, silicon Through hole (TSV), 2.5D/3D package, etc. Therefore, temporary bonding materials will play a vital role in the development of advanced packaging. In this paper, WLP LB310 is used as an infrared laser thermal decomposition material and temporary bonding glue for device wafer thinning and completing the backside processing technology (lithography, etching, passivation, electroplating, reflow soldering, etc.). After all the manufacturing processes are completed, the infrared laser irradiates the laser thermal decomposition material to undergo photothermal conversion, which causes the WLP LB310 to thermally decompose, and finally realizes the efficient and low-stress separation of thin wafers, and uses supporting cleaning agents to remove residual organic matter on the wafers. The results show that the temperature of the infrared laser pyrolysis material when the thermal mass loss of 1% in nitrogen is greater than 406°C; the bonding pair formed with the temporary bonding material has good chemical resistance; the film thickness is 1.4 nm infrared The laser pyrolysis material has no residual peeling after de-bonding under 1064nm Gaussian light, power 10w, and frequency 5000Hz.