Solar-grade silicon chip cut by using diamond wires and cutting method

Abstract

The invention discloses a solar-grade silicon chip cut by using diamond wires and a cutting method. The silicon chip cutting technology includes the monocrystal round silicon rod technology and the technology for cutting monocrystal square silicon rods by using diamond wires, wherein the monocrystal round silicon rod technology comprises the following steps: qualified round silicon rods are extracted and barreled by an extracting machine, and a mirror surface effect us achieved after flat grinding and polishing; and the technology for cutting monocrystal square silicon rods by using diamond wires comprises the steps: the surface of the silicon rods undergoing flat grinding and polishing is cleaned, then the silicon rods are bonded on resin rods, the resin rods are fixed on an adhesive board, the silicon rods and the adhesive board are arranged on a diamond wire cutting machine to be cut, and the solar-grade silicon chips are formed by the diamond wire cutting machine. As for the solar-grade silicon chip cut by using diamond wires, the processing technology is advanced and simple, the control precision is high, the silicon powder can be recycled, the manufacturing cost of the silicon sheets are reduced greatly, the phenomenon of breaking of wires are reduced, the production efficiency and the surface quality of the chips are improved, and the qualification rate is increased.

Description

technical field [0001] The invention relates to a solar grade silicon wafer cut by diamond wire and a cutting method thereof. Background technique [0002] At present, silicon wafers for solar cells are cut from monocrystalline silicon rods. At present, there is a shortage of silicon materials in the market, and the price is relatively high. In order to reduce production costs, many companies are making continuous efforts in thinning. At present, the thickness of silicon wafers for solar energy produced by most domestic and international enterprises is 200±20 um, and the mainstream thinning direction is silicon wafers with a thickness of 180±20 um. Application No. 200810019894.3 discloses an ultra-thin solar-grade silicon wafer and its cutting process. The thickness of the silicon wafer is between 165-195um, and the warpage is less than 75um. When cutting, it is necessary to use a mortar that is uniformly mixed with suspension and corundum. At the same time, the tradition...

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Problems solved by technology

[0004] (1) There is still a damaged layer on the surface of the silicon rod after squaring and chamfering, and the surface does not reach the mirror effect, which may cause disconnection during the cutting process and increase the fragmentation rate

[0005] (2) When cutting, it is necessary to use suspension and corundum to mix the mortar evenly. The mortar is difficult to recycle and cause serious environmental pollution.

[0006] (3) This kind of free mortar cutting is difficult to solve the problem of a large number of damaged layers on the surface of the silicon wafer, and the indicators of total thickness change (TTV), warpage (WARP) and curvature (BOM) will be too large, which limits the thinning

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