Lapping powder for grinding lithium niobate (LiNbO₃) and lithium tantalate (LiTaO₃) wafers?
Lithium niobate (LN) and lithium tantalate (LT) wafers are processed in distinct stages.
These piezoelectric crystals are brittle optical single crystals with moderate hardness. They are highly susceptible to subsurface cracks and scratches, necessitating a clearly defined, multi-stage processing sequence:
1. Rough Lapping (Post-slicing/thinning) — Green Silicon Carbide (GC) Micropowder
Green Silicon Carbide (GC) micropowder (in medium-coarse grit sizes such as 2000mesh or 1500mesh) is used after slicing to rapidly remove saw marks and excess material. It offers high cutting rates and excellent self-sharpening properties. However, it is strictly for rough lapping; it cannot be used for fine lapping, as it leaves a deep damage layer that would require extensive subsequent polishing to repair.
2. Double-Sided Fine Lapping — FO Polishing Powders and Domestic Alumina-Based Lapping Compounds
Industry Standard: FUJIMI FO series alumina (FO1200 is the most widely used).
Function: Controls Total Thickness Variation (TTV) and brings the wafer to a uniform, target thickness while keeping the damage layer shallow—thereby reducing the workload for the subsequent Chemical Mechanical Polishing (CMP) stage.
Characteristics: Gentle grinding action, rounded particle morphology, consistent batch-to-batch quality, and controllable scratching. FO1200 is extensively used by manufacturers of SAW filters and optical modulator substrates worldwide.
Domestic Alternative: An alumina-based lapping compound recently developed by Haixu Abrasives, which matches the composition and particle size distribution of Japan’s FUJIMI FO series.
Third-party test report on the composition of the alumina-based lapping compound from Haixu Abrasives.
Comparison table: Particle size distribution of Haixu Abrasives’ alumina-based lapping compound(AZ) vs. FUJIMI FO.
