Wafer level packaging for RF MEMS devices using void free copper filled through glass via

This paper presents a wafer-level RF MEMS packaging structure with void-free copper filled through glass via (TGV). The proposed structure was designed to package RF MEMS devices with vertical electrical interconnections through the glass substrate. In order to achieve void-free copper via through the Pyrex glass substrate with high aspect ratio and smooth side wall, glass reflow and seedless electroplating process were used. To test the RF performances of the proposed packaging structure, a packaged CPW transmission line was implemented. The CPW line is interconnected to the outer contact pads through vertical feed-throughs using the copper filled TGVs and encapsulated using the glass cap with a cavity. To investigate the mechanical robustness of the packaging, thermal shock and pressure cooker test (PCT) were performed for the packaged CPW line.