Advancements in fabrication of glass interposers

There is growing interest in applying glass as an interposer substrate for 2.5D/3D as well as component substrates for radio frequency (RF) applications. The list of important advantages provided by glass in these applications include material properties (e.g. electrical performance, ability to adjust coefficient of thermal expansion (CTE) to improve reliability) as well as the significant opportunities for cost advantages that glass based solutions provide over other approaches. The feasibility of fabricating high quality holes in glass substrates has been demonstrated. While work in hole fabrication continues, additional efforts to demonstrate and mature downstream processing of glass substrates has accelerated. These include hole metallization and redistribution layers (RDL) in both wafer and panel formats, as well as initial characterization and demonstration of reliability. Significant progress in these areas is reported here.