Development of a Cmp-Free Parylene-C/Cu Hybrid Bonding Structure With Low-Temperature Processing

This study presents a low-temperature polymer/Cu hybrid bonding technique enabled by a CVD-deposited parylene-C insulation layer. Unlike conventional polymer spin-coating and curing methods, the use of CVD paryleneC provides a more uniform dielectric layer. Its high thermal expansion coefficient eliminates the need for complex polymer planarization processes, and its molecular chain entanglement properties facilitate low-temperature bonding while relaxing surface roughness requirements. Experimental results demonstrate successful hybrid bonding at 200° C using a$1.2 \mu \mathrm{m} \text{Cu}$pillar array and a 1.1$\mu \mathrm{m}$thick parylene-C layer (protrusion height$\approx 100 \text{nm}$). This bonding is achieved without chemical mechanical polishing, as confirmed by subsequent structural analyses.