IR Laser Debond From Silicon Carrier Wafers With Inorganic Thin Film Release Layers for High-Density 2.5D and 3D Integration

Silicon carrier wafers without organic bond/debond layers enable new opportunities for 2.5D and 3D integration by offering an assembly platform with sub-micron total thickness variation (TTV), the best thermal/mechanical stability, and compatibility with high temperatures and all silicon wafer tools and processes. We have developed an infrared (IR) laser debond technology using inorganic thin films to control laser release from silicon carrier wafers and demonstrated the integration into high-density interconnect process flows. Using this technology, we demonstrate transfers of backend (BE) metal layers, 3-μm pitch hybrid-bond interconnects (HBI), and singulated chiplets from silicon carrier wafers to silicon receiver wafers without damage to any device layers, chiplets, or the silicon carrier. The mean resistance of transferred HBI daisy chains with over 4,000 hybrid-bonded contacts matches the calculated design value within 1.5% while 99% of the distribution is within 2% of the median, which demonstrates the technology for applications with hybrid bonding on temporary carriers. We also demonstrate damage-free IR laser debond of an organic inter-poser with two redistribution layers (RDL) including up to 333 lines/mm fabricated using our Zero-Misalignment-Via (ZMV) process technology on a silicon carrier wafer. We use an optical model to predict multi-layer absorption and transmission and demonstrate the benefits of a shield layer. Finally, we demonstrate the robustness and broad applicability of the technology.