Crackless glass through-structure fabrication with laser-induced backside wet etching using detachably bonded cover

We propose a novel process for fabricating crackless high aspect ratio glass through-structures in this study. A glass material was machined using laser-induced backside wet etching (LIBWE) and a detachably bonded glass cover. The uncontrolled spread of the liquid absorbent was prevented, which inhibited the crack generation by plasma-activated bonding and local fusion between the cover and workpiece. High aspect ratio crackless through-structures could be fabricated with inexpensive machining devices. The machined quality was investigated based on the machining principle of LIBWE. In the final step, various glass structures were machined to verify the range of machinable geometry.