Deep via and Trench Etching of Low CTE Glass Package Substrate Using SF6, NF3 and H2O Based NLD Plasma Process

Heterogeneous integration technology is attracting increasing attention in the progress of Moore's Law. In particular, expectations are growing for “3D chiplet integration” technology as new architecture integrates front end and back-end processes. As the chiplet integration technology is continuing to evolve, it is necessary to expand to multi layers to develop integrated 3D interconnect technology and optical waveguides on low CTE glass substrates that meet the signal integrity for high-frequency transmission with low power consumption. Although plasma dry etching of low CTE glass has traditionally been considered difficult, we have demonstrated a novel method by adding H2O to NLD plasma, achieving smooth and precise etching. This breakthrough presents a significant advancement in the fabrication techniques required for next-generation, highperformance, co-packaged optical devices.