A Single-Layer Solution with Laser Debonding Technology for Temporary Bond/Debonding Applications in Wafer-Level Packaging

Performance and cost are the two main driving forces for high demand of new advanced packaging technologies. It's not only OSATs and packaging houses that investigate advanced packaging systems anymore. Foundries and IDMs now also recognize that performance of devices can be significantly improved by advanced packaging technologies, which facilitate the evolution to next generation of process nodes, especially in the post-Moore's Law era. In this paper, several different innovative materials are presented as cost-efficient solutions to enable advanced wafer-level packaging applications. All of these materials are single-component, but with multiple functionalities, to facilitate wafer processes. The laser-sensitive thermoplastics perform as both bonding and laser debonding materials, and have been demonstrated in applications like wafer thinning, chip mounting, wafer flip, and epoxy compound wafer handling. The materials show good thermal stability (>300°C), high adhesion to various substrates, good response to different UV laser sources, and ease of cleaning with commonly used industry organic solvents. On other hand, a laser-sensitive thermosetting material is presented as well. In addition to the features mentioned above, the material can be wet-cleaned after debonding, which is a very unique property compared to other thermosetting materials, where a dry-etching process is required for cured material removal. A typical application for this material is to handle highly stressed substrates, like epoxy compound wafers (EMCs) such as in fan-out wafer-level packaging (FOWLP). With the unique combination of properties in these materials, a versatile toolbox is available to enable wafer processes in different advanced packaging applications.