Study on Laser-Assisted Reflow for C4 Bump Interfaces

This study presents the introduction and qualification of a contactless laser-assisted reflow process (LAR) aimed at forming stable and reliable C4 bump interfaces on semiconductor substrates for Flip Chip applications. The document outlines the challenges associated with conventional oven reflow processes, including high nitrogen and energy consumption rates, and proposes LAR as a potential solution. It details the methodology used, including the interaction of the laser with various materials and the characterization of solder bumps formed through this process compared to conventional methods. The study includes the description of test vehicles, the laser system utilized, and the parameters measured, such as bump height and shear tests. The findings indicate the effectiveness of LAR in reducing energy consumption and improving solder joint quality. Additionally, the document discusses the potential for upscaling the process and outlines future prospects for its application in semiconductor packaging.