Method for screen printing of fine mask on surface of silicon slice based on vacuum freeze drying technology

Abstract

The invention discloses a method for screen printing of a fine mask on the surface of a silicon slice based on vacuum freeze drying technology, which comprises the following processing steps: 1, cleaning organic matters on the surface of the silicon slice with mixed solution of H2SO4 and H2O2, washing the silicon slice with deionized water, and drying; 2, printing a liquid material on the surface of a substrate by a screen printing method to form a mask pattern, wherein the thickness of the mask is between 20 and 70mu m; and 3, performing vacuum freeze drying on the printed silicon slice, and immersing the silicon slice into mask cleaning solution to clear macromoleclar polymer on the surface after selective etching or injection doping. In the method, because a coating is quickly cured, the spreading of the coating on the substrate is limited, and the line width can be well controlled; and the mask prepared by the method has the minimum line width of 70mu m, and meets the requirement of solar cells. Compared with photoetching, the method does not need expensive equipment, and can greatly reduce the cost of manufacturing the mask.

Description

technical field [0001] The invention relates to a technique for screen printing fine mask patterns on silicon wafers, specifically a method for screen printing fine mask patterns on the surface of silicon wafers based on vacuum freeze-drying technology, which can be used for solar cells or integrated circuits manufacture. technical background [0002] In the local diffusion of solar cells, buried gate electrodes or integrated circuit wiring processes, a mask is used to selectively protect the silicon substrate to achieve local etching. The line width of the mask pattern is required to be less than 100um, which is called a fine mask (or fine mask). mask graphics). Photolithography is often used in the manufacture of solar cells and integrated circuits to make mask patterns. After photolithography and development, the mask pattern appears on the silicon wafer, and then a chemical etching process is used to image the thin film pattern on the silicon wafer, or it is sent to the...

AI Technical Summary

Problems solved by technology

This production method is complicated, requires high process conditions, and expensive equipment. According to S.Campbell's estimation, the cost of lithography accounts for almost one-third of the entire IC processing cost.

This expensive technology is not suitable for commercial solar cell production applications

[0004] The printed circuit board industry uses screen printing technology to print ink on copper-clad resin boards as an etching mask for circuits. This technology has low requirements for process and equipment, and is a low-cost mask technology. Heating and curing, the ink spreads on the substrate during this process, making the edges of the ink unclear, and the line width is difficult to control. The minimum line width it can obtain is about 300um, which is far from meeting the requirements of the solar cell industry.

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