Improved copper electroplating method of crystal silicon solar battery

Abstract

The invention relates to an improved copper electroplating method of a crystal silicon solar battery. The silicon nitride layer on the surface of the conventional battery has many pin holes, and in the process of preparing copper (Cu) electrodes by an electroplating process, the Cu electrodes are easy to be adsorbed to the pin holes of the silicon nitride layer to lead to blur in appearance of the solar battery. Meanwhile, the copper electrodes are easy to seep into the silicon nitride layer and a silicon-based interface through the pin holes, and Cu as a deep energy level impurity with very fast diffusion rate entering into a pn junction affects the service life and generating efficiency of the battery, so that the reliability of the battery is reduced. A protective film covers the surface of the silicon nitride layer before Cu electroplating to prevent Cu from being adsorbed and seeped in the electroplating process, so that the reliability of the battery is guaranteed while the blur in appearance of the solar battery is avoided. The protective film can be removed after Cu electrode electroplating. According to the technological requirements of the crystal silicon batteries, the protective film can be still remained if parameters of the battery such as optical and electrical properties and reliability are not affected.

Description

technical field [0001] The invention relates to a manufacturing process of a crystalline silicon solar cell, in particular to an improved copper electroplating method for a crystalline silicon solar cell. Background technique [0002] With the increasingly tense global resources, solar energy has unique advantages such as no pollution, no mechanical rotating parts, easy maintenance, unattended operation, short construction period, random scale, easy combination with buildings, and large market space. The advantages are widely valued by countries all over the world, and many large companies in the world have invested in the research and development and production of solar cells. With the development of technology in the past ten years, although the application cost of silicon solar cells has dropped significantly, in order to meet the needs of wide application in real life, it is necessary to further reduce the manufacturing cost and at the same time further increase the conv...

AI Technical Summary

Problems solved by technology

However, after using plate PECVD (Plasma Enhanced Chemical Vapor Deposition) to plate silicon nitride on traditional crystalline silicon cells, it is easy to cause surface patterns when performing Cu electrode plating process; The silicon nitride plating layer is denser, but it is easy to make the silicon nitride layer contain more pin holes in the process of industrial mass production, and Cu is easily adsorbed on the silicon nitride during subsequent Cu electrode plating. layer holes and penetrate into the silicon nitride layer and Si-based interface, affecting battery life and power generation efficiency

Cu is a deep-level impurity, and its diffusion speed is very fast. After entering the semiconductor material, it acts as a recombination center, promoting the recombination of semiconductor carriers and reducing the lifetime of minority carriers; at the same time, Cu scatters carriers, making the carrier mobility Decrease, reduce electrical conductivity

In addition, if under the traditional process without protective film protection, the laser is used to directly perform high-temperature etching on the surface of the silicon nitride layer, amorphous impurities are prone to appear on the edge of the grid line position of the battery, which affects the reliability of the battery.

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