Cleaning method of graphite boat for manufacturing solar cells

Abstract

The invention provides a cleaning method of a graphite boat for manufacturing solar cells. The cleaning method of the graphite boat for manufacturing the solar cells comprises the steps that the graphite boat with impurities is put into a vacuum sintering furnace to be subjected to vacuum high-temperature sintering, the impurities attached to the graphite boat are changed into gas to be separatedfrom the graphite boat in the vacuum high-temperature sintering process, the gas converted from the impurities is pumped away by a vacuum pump and conveyed to a tail gas treatment system to be subjected to tail gas purifying treatment, and then the impurities such as foreign matter film on the surface of the graphite boat are burnt off. According to the cleaning method of the graphite boat for manufacturing the solar cells, the graphite boat can be cleaned up in a short time, no chemical agent such as HF acid is used in the whole process, no environmental pollution hidden danger exists, the environmental protection pressure for factories is reduced, no harm is generated to operating personnel, and the cleaning efficiency and the cleaning effect are improved; the graphite boat does not needto be disassembled, and damage to the graphite boat in the disassembling process is avoided; and in addition, few treatment link is needed, the cleaning time is short, and the production efficiency is higher.

Description

technical field [0001] The invention relates to the technical field of tubular PECVD, in particular to a method for cleaning graphite boats used for manufacturing solar cells. Background technique [0002] Solar cells are divided into crystalline silicon and amorphous silicon, and crystalline silicon cells can be divided into monocrystalline cells and polycrystalline cells. The production process of solar cells is as follows: silicon wafer detection→surface texturing and pickling→diffusion PN junction→phosphorous silicon glass→plasma etching and pickling→PECVD anti-reflection coating→screen printing positive and negative electrodes→ Fast sintering etc. [0003] Among the above, PECVD anti-reflection coating: the reflectivity of the polished silicon surface is 35%. In order to reduce surface reflection and improve the conversion efficiency of the battery, a layer of silicon nitride anti-reflection film needs to be deposited; PECVD equipment is often used in industrial produc...

AI Technical Summary

Problems solved by technology

The cleaning efficiency of the graphite boat and the quality of the cleaning effect greatly affect the production efficiency of the tubular PECVD system and the quality of the coating. If the cleaning method is not proper, not only is too much production time wasted, but the cleaning effect is not good , in the production of coating, the thickness of the film is difficult to control, and the proportion of color difference increases, which seriously affects the production efficiency and benefit

[0007] At present, the graphite boat is generally cleaned by immersing in HF acid liquid, then rinsed with pure water, and then air-dried and oven-dried. There are many links and the cleaning time is very long. First, the whole graphite boat is immersed in HF Put the acid in the tank for about 6 hours, then rinse it with deionized pure water for 2 hours, and then dry it in the oven for 6-8 hours. One pickling tank can only process 4 graphite boats at the same time, which is inefficient, and hydrofluoric acid is harmful to the environment. It is harmful to the human body, and it is difficult to recycle the waste HF acid produced after a period of use