Glass PCB

This type of printed circuit board is made using a glass substrate (borosilicate glass, fused silica glass, soda-lime glass, or sapphire glass) instead of FR-4 laminate. Copper conductors are deposited on the glass substrate through sputtering and electroplating processes, creating a very smooth, fine circuit on a flat, transparent, and dimensionally stable medium.

Prototype production costs are approximately 5-20 times that of FR-4 boards: 10 50×50 mm double-sided borosilicate boards cost approximately $45-$120 each, plus $300-$700 for mold costs. If using soda-lime glass boards for panel-level mass production, the cost per board can be less than $5. Please use the T-03 estimator above to calculate your geometry.

Components can be attached using soldering, conductive adhesive, wire bonding, flip-chip bonding, or other packaging methods. The specific process used depends on pad surface treatment, component type, and thermal requirements.

Thin-film lithography typically achieves linewidths/spacings of 10–50 µm, while semi-additive processes can achieve below 5 µm. Printed or laser-structured conductors are larger, ranging from 75–150 µm. Sub-nanometer glass surfaces significantly reduce conductor edge roughness, thereby substantially reducing RF losses.

Through-Glass Vias (TGVs) are formed by first using laser-induced deep etching (LIDE) or laser drilling, followed by hydrofluoric acid (HF) etching, and finally metallization through sputtering of a seed layer and copper plating. Typical diameters are 30–100 µm, with spacing up to 150 µm and an aspect ratio of approximately 10:1.

The main cost factors include glass material, substrate size, thickness, number of TGVs, via size, circuit density, metallization, surface finish, testing requirements, and production quantity.