Preparation and functionalization of LTCC substrate surfaces for advanced integration applications using thin film process

This study introduces a multi-step surface preparation and functionalization process to optimize low-temperature co-fired ceramic (LTCC) substrates for high structural resolution, thin-film compatibility, and potential direct semiconductor material deposition in electronic and microelectronic devices. The process integrates lapping, chemical mechanical polishing (CMP), and sol-gel coating using methyltrimethoxysilane (MTMS) precursors. CMP significantly improves planarity and reduces surface roughness, lowering the average roughness (Rq) from 300 nm to 90 nm and Ra from 210 nm to 40 nm. The sol-gel coating further refines the surface, achieving a roughness of 25 nm, while reducing porosity and increasing hydrophobicity, as indicated by a water contact angle of 109°. Refractive index measurements of the transparent sol-gel coating reveal a value of 1.406, confirming enhanced dielectric properties. These surface modifications improve LTCC planarity and compatibility with high-frequency applications. Additionally, the functionalized surfaces enhance LTCC's integration with semiconductor materials, demonstrating its potential for advanced heterogeneous integration. This approach opens up possibilities for innovations in RF communications, photonics, and power electronics. By improving both the structural and functional properties of LTCC, this work contributes to the development of efficient and reliable next-generation electronic devices. • Multi-step lapping, CMP, and sol-gel coating improved LTCC surface planarity and smoothness. • Surface roughness reduced from Rq 300 nm–90 nm and Ra 210 nm–40 nm post-processing. • MTMS-based sol-gel coating reduced porosity and enhanced adhesion and mechanical properties. • Transparent sol-gel films achieved a refractive index of 1.406 for RF/optical applications. • Process improves LTCC compatibility for advanced semiconductor device integration.