Fabrication of a through glass via in a relatively thick glass substrate includes patterning a through glass via hard mask on a surface of the glass substrate. The fabrication also includes wet etching a portion of the glass substrate, through the hard mask, to create a partial through glass via. The wet etching may involve applying a vapor of an oxide etch chemical, such as HF and XeF6, or applying a wet oxide etch chemical, such as HF and XeF6. The fabrication further includes passivating the etched partial through glass via, removing bottom passivation from the partial through glass via, and repeating the etching, passivating and removing to create the through glass via. The resulting through glass via has a scalloped side wall, a vertical profile and a high aspect ratio.