Large-scale ultra-thin high-precision lithium niobate wafer processing method

Abstract

The present invention relates to the technical field of semiconductor material processing, in particular to a method for processing a large-sized ultra-thin high-precision lithium niobate wafer, the method comprising slicing, chamfering, grinding 800, blackening, grinding 2000 and polishing steps; the grinding 800 Both the step and the grinding step 2000 use a double-sided grinder, and at 22°C ± 2°C, the grinding pressurization method adopts a segmented and slow pressurization method; , the maximum speed of the equipment is 6-10rpm, using SiO 2 Polishing liquid, the specific gravity is 1.06-1.20, and the polishing pressurization method adopts the segmented and slow pressurization method. Due to the slow and gradual pressurization method during pressurization, the scratches, fragments, slivers, etc. are greatly reduced. At the same time, the fixture of the present invention can effectively reduce the collapse, edge burst, and insufficient grinding. It greatly improves the yield rate of production and gets rid of the traction of manufacturers' semiconductor machine equipment applications.

Description

technical field [0001] The invention relates to the technical field of semiconductor material processing, in particular to a processing method for a lithium niobate crystal substrate. Background technique [0002] Lithium niobate (LiNbO 3 ) is a compound of niobium, lithium and oxygen, which is a negative crystal (n0>ne). The relative density of lithium niobate is 4.30, lattice constant a=0.5147μm, c=1.3856μm, melting point 1240°C, Mohs hardness 5, refractive index n0=2.297, ne=2.208(λ=600μm), dielectric constant ε=44 , ε=29.5, ε=84, ε=30. Lithium niobate is a ferroelectric crystal with a Curie point of 1140°C, a spontaneous polarization of 50×10C / cm', and a thermal conductivity of 0.056 (W / cm·K). The distorted lithium niobate crystal has piezoelectric, ferroelectric, photoelectric, nonlinear optical, thermoelectric and other multi-performance materials, and has photorefractive effect at the same time. Its single crystals are important materials for optical waveguides...

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Problems solved by technology

[0005] Chinese patent application CN111230598A discloses a method for preparing an 8-inch lithium niobate wafer, which solves the serious internal stress deformation of the lithium niobate wafer and the problem of easy cracking during the wafer production process by using three etching methods; Porous ceramic plate adsorption solves the problem that TTV is not easy to control caused by the traditional wax sticking process; but in actual operation, the acid used for corrosion has potential safety hazards to the environment and human body, and the use of porous ceramic plate adsorption has a negative impact on equipment and accessories. The precision requirements are extremely high, and only one-side polishing can be achieved

However, the physical properties of lithium tantalate and lithium niobate are very different, and the processing method of lithium tantalate is not suitable for lithium niobate

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