Novel IR Laser Debonding for Heterogeneous and 3D Integration

Abstract

Wafer carrier and thin wafer support during processing is key in 3D integration and advanced packaging processes. Today carrier technology can be divided based on the application and carrier wafer material. While for DRAM and other stacked memory applications silicon carriers are preferred, demanding special adhesive systems for mechanical debond, the adhesion is tuned to be high enough for processing but low enough for post process thin layer debonding. Which means the thin wafer thickness needs to be maintained typically thicker than 40µm in order to have a sufficient mechanical rigidity and support during debonding. On the other hand, UV based laser debonding decouples the adhesion during processing while the debonding is digitally triggered by UV laser irradiation and controlled destruction of engineered polymeric layer at the glass carrier surface. Despite this is the more universal debonding process, glass wafers are generally not suited for all process lines. To solve the above described difficulties, IR laser debonding has been developed enabling the combination of silicon as a carrier substrate as well as laser debonding through silicon. One solutions is in advanced packaging, where silicon can be seen as a replacement for glass wafers but still in combination with developed adhesive systems. The more impacting application, however, is the combination of IR laser release with fusion and hybrid bonding.