SATPC0041564 Tab 04 4 SOW.pdf

This is a Statement of Work (SOW) for dry etching services on a combined Gallium Nitride epitaxial layer and Silicon Carbide substrate. The vendor shall fabricate and process one 3-inch diameter, approximately 350-micron thick single crystal 4H-SiC wafer that is pre-electroplated with a patterned nickel etch mask.

The primary deliverable requirements include: etching the wafer to 280 microns depth to create a diaphragm with approximately 70-micron thickness and radii ranging from 300 to 900 microns; achieving diaphragm thickness uniformity of ±5% across the 3-inch wafer; producing smooth diaphragm surfaces with fewer than 5 micro mask artifacts per surface; ensuring diaphragm features are smooth and free of scallops; maintaining a reasonable radius at the diaphragm base-to-sidewall intersection without notching; eliminating edge-wall trenching artifacts at the base-sidewall intersection; and achieving an aspect ratio (etched depth/etched width) of no less than 5, with higher ratios preferred. Additionally, the vendor shall dry-etch the top side p-GaN layer to 3 micrometers using a provided SiO₂ etch mask to expose the 4H-SiC surface, confirm the etched depth measurements, perform solvent cleaning in acetone followed by isopropanol, and provide depth confirmations. The etch recipe methodology shall be determined by the foundry.