A method for cutting ultra-thin silicon wafers with ultra-thin steel wire

Abstract

The invention relates to a method for cutting ultra-thin silicon wafer by a superfine steel wire. The method comprises the following steps of: (1) forming slots in a man shaft; (2) sticking bars; (3) preparing a cooling liquid; (4) cutting; (5) unloading; (6) degumming and cleaning; and (7) detecting; the cooling liquid prepared in the step (3) is pure water and a water-based cutting fluid with concentration being 0.6%-2.0%; and during cutting in the step (4), cutting steel wires are 60 [mu]m diamond wires, diamond particles are particles with diameter being 6-8 [mu]m, tension is set to be 7-9 N, and slot pitch of the main shaft is 0.19-0.210 mm. According to the method, single crystal slicing yield is further reduced, slicing thickness is reduced, silicon loss is reduced and processing cost is reduced; and meanwhile, a wire braking rate can be reduced, yield is increased, and wire doubling is avoided.

Description

technical field [0001] The invention relates to a silicon chip cutting process, in particular to a method for cutting an ultra-thin silicon chip with an ultra-thin steel wire which further reduces slice thickness, reduces silicon consumption, and reduces processing costs. Background technique [0002] The production of crystalline silicon solar modules includes crystalline silicon production, ingot casting / pulling, slicing, cell production and module production. Since the thickness of silicon wafers has no effect on the photoelectric conversion efficiency of solar cells, improving the utilization of silicon materials becomes a reduction in silicon wafer processing. One of the important ways of cost. The slicing link is the process of cutting the silicon ingot into thin slices. The slicing is to bring the SIC abrasive into the processing area (silicon rod) through the high-speed reciprocating motion of the metal wire for grinding, and the diamond wire is to attach the diamond...

AI Technical Summary

Problems solved by technology

[0003] In order to reduce the cost, reducing the thickness of the silicon wafer is an effective method, but cutting the steel wire too thin will cause problems: in the production process of the steel wire, the smaller the diameter of the busbar, the more difficult it is to draw the wire, the higher the broken wire rate, and the lower the yield rate; The smaller the diameter of the steel wire during the cutting process, the smaller the tension required during cutting, and the higher the requirements for the tension control system of the cutting equipment; the thinner the wire diameter of the busbar, the cutting ability of the steel wire will be affected during the cutting process, and the risk of wire breakage will be lower. It will increase; the thinner the steel wire, the smaller the spindle groove distance, the smaller the distance between the steel wires, and under the action of cooling water, the steel wires will be easier to merge together, and the temperature increase can properly reduce the surface tension of the liquid, but the temperature The increase will affect the cooling performance of cutting fluid, etc.

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