Photonic Debonding for Wafer-Level Packaging

Temporary bonding and debonding (TB/DB) processes have emerged as promising solutions in wafer-level packaging technology. These processes offer a pathway to wafer thinning and subsequent backside processing, which are crucial in enabling heterogenous integration using technologies such as 3D through-silicon-vias (TSVs) and fan-out wafer-level packaging. These are critical for overall device miniaturization and increased performance. In this work, a novel photonic debonding (PDB) method and the corresponding bonding material are presented. PDB enhances the TB/DB process by overcoming many of the disadvantages associated with traditional debonding methods. PDB uses pulsed broadband light (200 nm – 1100 nm) from flashlamps to debond temporarily bonded wafer pairs with glass as the carrier wafer. These flashlamps generate high-intensity pulses of light (up to 45 kW/cm2) over short time intervals (~100 μs) to facilitate the debonding. Feasibility of the PDB in the TB/DB process is demonstrated by successfully debonding thinned (<70 μm) silicon wafers from glass carriers. Post-debond cleaning of the thinned wafers and carriers is evaluated. With uniform, large-area illumination (75 mm x 150 mm) per flashlamp and with the ability to concatenate lamps to increase the illumination area of the PDB tool, the PDB method offers a high-throughput and low-cost debonding solution for both wafer-level and panel-level packaging technologies.