Chip-on-Wafer (CoW) Technology Utilizing Laser-Assisted Bonding with Compression (LABC) for Bump Counts Exceeding 500,000 at a 20 μm Pitch

There are many technical issues regarding chiplet integration. For example, there are technical concerns about how to obtain clean and reliable solder cap surfaces, Cu RDL and pillars below 40μm pitch, and how to achieve precise bonding accuracy during the Chip-on-Wafer (CoW) bonding process.In this paper, we propose a room temperature homogenized laser with water-soluble laser epoxy flux as the technical candidate solution to the first issue, and the room temperature Laser-Assisted Bonding with Compression (LABC) with laser Non-Conductive Film (NCF) for the second problem, and compare it with other bonding technologies. The properties of the proposed materials, a key enabling technology for the tiling process, will be introduced. Using the CoW process, a prototype of chiplet integration with bump counts exceeding 500,000 at a 20μm pitch was demonstrated as a test study.