Indium Phosphide (InP) Semiconductor Processing Technology
Table of Contents
Introduction
Application Requirements
System Specifications
Processing Flow
Customer Case
Application Requirements
InP wafer processing must achieve the following objectives:
Surface Roughness: Post-polishing Ra ≤ 1 nm
Total Thickness Variation (TTV): Final wafer TTV ≤ 2 µm
Thickness Control: Target thickness 150 µm (subject to customer requirements)
Edge Flatness: Compensate for edge warping during the polishing stage using a convex grinding platen.
System Specifications
The HSM Precision Grinding and Polishing System provides a full-process solution.
Processing Flow
Grinding Preparation
Use a flatness test gauge to calibrate the convexity of the glass grinding platen (used to compensate for polishing edge effects).
Load the InP wafer onto the dedicated fixture (ASJ). Perform two-stage grinding using alumina slurry:
Stage 1: Remove cutting damage, reducing roughness to 250-350 nm.
Stage 2: Improve flatness, achieving roughness of 200-350 nm and TTV ≤ 3 µm.
Polishing Preparation
Replace the Lapping platen with a polishing pad and switch the abrasive to HSM specialized polishing slurry.
Control key parameters via the graphical interface:
Polishing platen speed: ≤ 100 rpm
Slurry flow rate: Monitored by a real-time drip feed control system (reduces waste)
Pressure load: Dynamically adjusted based on thickness requirements.
Target: Remove sub-surface damage and achieve an atomically smooth surface (Ra ≤ 1 nm).
Results
The 2-inch InP wafers processed by the HSM-LP system achieved the following performance:
Customer Case
A customer used the HSM-LP system to process 2-inch (50 mm) InP wafers. The process and results are as follows:
Two-Stage Grinding:
Lapping platen convexity calibrated to the target curvature (to counteract edge warping).
Material removed stepwise with alumina slurry, TTV stabilized at 3 µm.
Polishing:
Polishing slurry flow rate set to 50 ml/min, platen speed at 80 rpm.
Surface roughness reduced from 350 nm to 1 nm (verified by Dektak profilometer).
Final Metrics:
Thickness: 150 ± 0.5 µm
Flatness: TTV ≤ 1 µm
Edge Integrity: No chipping.
Technical Validation
Schematic: Surface morphology of the InP wafer after processing by the HSM-LP system.
Notes:
Measurement Equipment: Bruker ContourGT White Light Interferometer
Full-Process Yield: ≥ 98% (batch size of 80 wafers)
