Cooling liquid for diamond-wire cutting equipment, and preparation method thereof

Abstract

The invention provides a cooling liquid for diamond-wire cutting equipment, and a preparation method thereof. The cooling liquid consists of: 2.5 wt%-90 wt% of deionized water, 2 wt%-86 wt% of diethylene glycol, 0.1 wt%-10 wt% of polyethylene glycol with an average molecular weight of 100-2000, 1 wt% -30 wt% of a dispersant, 0.01 wt% -10 wt% of a chelating agent, 0.1 wt% -10 wt% of a metal corrosion inhibitor and 0.01 wt% -5 wt% of an antifoaming agent. The preparation method comprises: successively adding the chelating agent, the metal corrosion inhibitor and the antifoaming agent into deionized water according to the ratio, uniformly stirring; and then adding diethylene glycol, the dispersant and polyethylene glycol, stirring for 6-8 hours to prepare the cooling liquid for the diamond-wire cutting equipment. The cooling liquid for the diamond-wire cutting equipment has the characteristics of good cooling effect, moderate silicon-powder suspension capability, low viscosity, few foams and low corrosivity, and is simple in manufacture and low in cost.

Description

technical field [0001] The invention relates to a cooling liquid used in a silicon wafer cutting process, in particular to a cooling liquid used for diamond wire cutting single crystal silicon. Background technique [0002] At present, the materials used in solar photovoltaic cells mainly include amorphous silicon, polycrystalline silicon, single crystal silicon, and III-V compound compounds. Among them, monocrystalline silicon has high photoelectric conversion efficiency, the material itself does not pollute the environment, has a wide range of material sources, and has stable performance. In the manufacturing process of monocrystalline silicon cells, it is necessary to cut the Czochralski monocrystalline silicon rod into silicon wafers with a thickness of about 200um. [0003] Now there are mainly two ways of cutting: mortar multi-wire cutting and diamond wire multi-wire cutting. Compared with mortar cutting, diamond wire cutting has the characteristics of high cutting e...

AI Technical Summary

Problems solved by technology

[0007] The current marketed coolant usually has the following problems during use: (1) The cooling effect is not good

During the cutting process, the temperature of the silicon ingot rises above 30°C. In addition to poor slicing, it is also easy to soften the sticky glue, causing the chips and rods to fall off, causing huge losses.

(2) Suspension of silicon powder is too good or too poor

If the suspension is too good, the silicon powder will easily enter the slit repeatedly with the coolant, which will reduce the cutting efficiency of the diamond wire and cause poor TTV; if the suspension is too poor, the silicon powder will easily deposit on every corner of the equipment, especially In the plate heat exchanger, the heat exchange between the coolant and the process cooling water is poor, and the temperature of the coolant cannot be effectively reduced, resulting in poor cutting

(3) It is easy to generate air bubbles during recycling

During the cutting process, a large number of air bubbles exist on the surface of the diamond wire, which greatly reduces the cooling liquid that actually participates in cooling and suspension, resulting in uneven temperature distribution on the surface of the silicon wafer, which is prone to defects such as debris and line marks.

(4) Part of the acidic coolant is easy to corrode the steel wire

Most of its products are imported products with high prices. In order to further realize clean production, reduce costs, and improve cutting quality, a new localized cooling fluid is needed to meet the requirements of diamond wire cutting monocrystalline silicon.

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