Thin glass substrates with through vias (TGV) have excellent properties for a new generation of interposers. Glass has a large bulk resistance and low loss at high frequency (RF, mmWave). Physically, it is moisture insensitive, highly dimensionally stable, and has a thermal expansion coefficient that can be tailored to match silicon. The surface of as-received glass has roughness below 1 nm, like silicon wafers, and thus supports fine line/space patterning and advanced processes like damascene. A key focus of our current work involves metallizing thin glass interposers with TGVs, including both copper electroplating of TGVs and patterning of redistribution layers. We demonstrate void-free fill for vias ranging from in aspect ratio from 2:1 to 8:1, in a bottoms-up process like that used for through silicon vias. The vias are hermetic by helium leak detection, even after annealing in some cases to 450C. Since thin (≤ 200 micron) free-standing glass substrates are difficult to handle in current fabs, we discuss an advanced temporary bond approach using silicon or glass handles which enables high-yield processing. The bond is robust to temperatures exceeding 400 °C, and creates handle/glass stacks with total thickness variation (TTV) similar to that of a silicon wafer. The end result is a bonded pair that can be processed like a silicon wafer, with a simple mechanical debond to yield the processed thin glass. We discuss the bond and debond processes, showing the ability to control the bond strength. Data on the bonded glass stack resistance to various processing steps will also be shown.