Advanced Photonic Debonding Using Solution-Processed Ag Nanoparticle/Cu-Precursor Hybrid Light-Absorbing Layers for Wafer-Level Packaging

Abstract

This study presents an advanced photonic debonding (APDB) process for wafer-level packaging using millisecond-intense pulsed light (IPL) irradiation and a solution-processed Ag nanoparticle (NP)/Cu-precursor hybridIPL-absorbing layer (IAL, MyCin–C). The notation 7:3 denotes the feed mass ratio of Ag NPs to Cu( $\mathrm{NO}_{\textrm {3}})_{2}~{\cdot }~3$ H₂O precursor and does not represent the final elemental Ag:Cu ratio. A 2-butoxyethanol-based formulation provided improved wettability and coating uniformity compared with a DI water-based formulation, resulting in a more homogeneous photothermal response and improved carrier-glass reuse. Among the investigated formulations, the 7:3 hybridIAL exhibited broadband optical absorption of approximately 95% and the highest transient photothermal response. Wafer-level debonding was demonstrated on a 150-mm silicon wafer thinned to approximately $30~\mu $ m using a single IPL pulse at 4 J/cm2 with a pulse duration of 1 ms. In contrast, an Ag-only NPIAL fabricated under comparable coating, bonding, and wafer-processing conditions did not achieve debonding at 4, 5, or 6 J/cm², and carrier-glass cracking occurred at 6 J/cm2. These results establish a direct relationship among absorber formulation, coating morphology, optical absorption, transient photothermal response, and interfacial separation behavior. Post-debonding optical microscopy (OM), scanning electron microscopy (SEM), FIB-SEM, and semiquantitative EDS analyses showed no pronounced cracking, interfacial delamination, structural deformation, or major redistribution of the detected elements within the analyzed regions. The total device multilayer-stack thickness remained comparable before and after debonding, and neither Ag nor Cu was detected on the analyzed wafer regions under the applied EDS conditions. In addition, the 2-butoxyethanol-based carrier glass retained high optical transmittance over repeated debonding–cleaning–reuse cycles. These results demonstrate the feasibility of localized, single-pulse IPL debonding for thin-wafer handling and advanced semiconductor packaging under the tested process conditions.