A method for industrial printing alignment of crystalline silicon selective emitter

Abstract

Disclosed by the present invention is an industrial printing alignment method for a crystalline silicon selective emitter, comprising the following steps: step 1: silicon wafer pre-treatment; step 2: P-N junction preparation; step 3: SE laser doping; step 4: MARK point preparation: adjusting laser parameters such that laser marking energy of a MARK point in a laser preparation process must be higher than SE laser doping energy; step 5: silicon wafer re-treatment; step 6: back-face silk screen printing; step 7: front-face alignment silk screen printing; step 8: sintering testing. The present invention performs two modification methods on a existing laser MARK point of SE technology, wherein laser marking energy of a new MARK point in a laser process must be higher than laser doping line energy, such that the chromaticity and morphology of a laser area is significantly different from that of a non-laser area. At the same time, a square MARK point is punched out by a square laser spot to eliminate edge irregularity, which is beneficial to the naked eye in confirming and observing whether the offset of a machine after printing exceeds a standard amount and the offset direction, and is thus very worthy of promotion.

Description

technical field [0001] The invention relates to the technical field of screen printing, in particular to an industrialized printing alignment method for crystalline silicon selective emitters. Background technique [0002] With the continuous development of crystalline silicon technology, the expansion of solar cell production scale and the continuous reduction of cell prices, reducing production costs and improving efficiency are the focus of cell technology development. For the existing conventional perc cells, the front side has higher junction depth and phosphorus concentration, while the high recombination of the reflector leads to lower open voltage and short circuit current, and the selective emitter electrode is due to its location in the area receiving light Low-concentration doping, high doping under the metal gate line, forming a lateral high-low junction structure to increase the potential difference between the P-N junctions, reducing the recombination of the di...

AI Technical Summary

Problems solved by technology

[0003] A significant problem in the mass production of existing crystalline silicon selective emitter solar cells is the alignment of printed grid lines and SE laser-doped lines. The adjustable offset window of printing is only about 30 μm, and lasers are needed in actual production. Precise alignment between the doped line and the center of the printed grid line. In the existing technology, the alignment problem leads to two more obvious defects:

[0004] 1. Both use the MARK point that is laser-printed and aligned during laser doping. The MARK point is a solid circle with a diameter of 0.5mm. In actual mass production, due to the color difference and shape of the laser-doped area and the non-doped area There is almost no difference in the impurity area, and after SE laser doping, it needs to go through 6 production processes before printing, and the basic alignment and offset cannot be observed with the naked eye;

[0005] 2. Because the shape of a single laser spot is square, the edge of the alignment point circle will be irregular when the laser emits a circular alignment point, which will cause the CCD to capture and recognize the MARK point when the printing camera aligns the MARK point. Bias creates an additional offset

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