Method for measuring screen plate overlay accuracy of solar cell

Abstract

The invention discloses a method for measuring the screen plate overlay accuracy of a solar cell. The method comprises the following steps of: a, determining the coordinates of the center positions of four positioning points of a first screen plate and the center line of a thin-grid outer frame line, and measuring the vertical distance from the center positions of the four positioning points of the first screen plate to the center line of the thin-grid outer frame line respectively; b, measuring the vertical distance from the center positions of the four positioning points of a second screen plate to the center line of the thin-grid outer frame line respectively in the same way; c, judging whether the X-axis and Y-axis offset distance of the second screen plate is within the required range of the overlay accuracy; and d, cross-connecting the four positioning points of the first screen plate to form a horizontal line and a vertical line, and measuring the parallelism or perpendicularity between a horizontal line or vertical line and the center line of corresponding outer frame line; measuring the parallelism or perpendicularity of the second screen plate in the same way; and obtaining the offset of the screen plate rotation position according to the difference between the two parallelisms or perpendicularities. According to the invention, the problem of X-axis and Y-axis offset of the sizes of two screen plates is solved, and angular offset caused by the rotation of the whole screen plate is avoided.

Description

technical field [0001] The invention relates to a method for measuring the engraving precision of a solar cell net plate. technical background [0002] Solar cells use the principle of photovoltaic effect to convert solar radiation energy into electrical energy. Solar cells are essentially a two-junction tube of a large-area semiconductor PN junction. Traditional solar cell preparation methods have little room for improving the conversion efficiency of solar cells. The selective emission junction SE process and the two-time printing process of the positive electrode can greatly improve the conversion efficiency of solar cells. Selective emitter junction SE process, a mature process at present, is generally formed by two diffusion methods. The basic principle is to divide the original single diffusion into two steps to form a re-expansion area and a light-expansion area. To form areas with different diffusion resistance, surface concentration and junction depth, it is nece...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a method for measuring the overlay accuracy of the stencil to solve the problem of two stencil offsets caused by the existing measurement method

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