Key Indicator

Parameter Range

Remarks

Aspect Ratio

10:1 ~ 50:1 (Up to 100:1 in labs)

Glass processing is harder than silicon, but advanced laser processes have improved this significantly.

Via Diameter

5µm ~ 100µm

Glass is brittle; small vias require high-precision laser or etching.

Glass Thickness

50µm ~ 1100µm

Common thickness is 100µm-500µm; ultra-thin glass processing is a trend.

Dielectric Loss

Very Low (tan δ ≈ 0.001)

Glass has much lower RF loss than silicon, ideal for 5G/6G applications.

Parasitic Capacitance

Low

No extra dielectric layer needed; direct metallization results in lower capacitance.

Resistance

< 10 mΩ

Uses copper electroplating like TSV, offering excellent conductivity.

Substrate Material

Quartz, Borosilicate, Ultra-thin Glass

Coefficient of Thermal Expansion (CTE) matching is critical to prevent cracking.

Via Formation

Ultrasonic Drilling, Laser Etching, Photo-structurable Glass

Photo-structurable glass (e.g., Foturan) allows semiconductor-like photolithography.

Metallization

Seed Layer Sputtering + Cu Plating

Key challenge is uniform seed layer coverage on deep hole sidewalls.