A new method of forming through holes in GaAs substrate by wet etching

摘要

The via hole of GaAs substrate for MMIC and digital integrated circuit is formed by the following steps: (a) polishing the GaAs substrate with sand paper and alumina powder of 0.05-1m thickness; (b) etching the substrate using the NH4OH / H2O2 / H2O solution for mirror face polishing of rough surface; (c) sticking the substrate to the micro slide glass using Az1375 photoresist for preventing the cracking of substrate; (d) etching the substrate at temperature of 60-70 deg.C using the etching solution containing the 80ml (85W/O) H3PO4 : 80ml (30W/O) H2O2 : 30ml H2O ratio.