A stacked high temperature annealing process

Abstract

The invention discloses a stackable high-temperature annealing technology. The technology comprises the following specific operation steps that 1, etched silicon wafers are stacked in order and put into a quartz sheet frame for annealing; 2, the silicon wafers on the quartz sheet frame are covered with a quartz cover plate and pressed, and the quartz sheet frame is fed into a high-temperature diffusion-oxidation furnace; 3, annealing is conducted by increasing and stabilizing the temperature of a furnace tube of the high-temperature diffusion-oxidation furnace; 4, temperature decreasing and discharging from the furnace are conducted, wherein the temperature of the furnace tube of the high-temperature diffusion-oxidation furnace is decreased, and the quartz sheet frame is discharged from the furnace. The stackable high-temperature annealing technology has the advantages that the surfaces of the stacked silicon wafers are isolated from air, and therefore the problems existing in a thermal oxidation technology are effectively solved; operation is easy, the consumed time is short, and quantity production is easy to achieve; meanwhile, the yield is high, the battery piece efficiency is significantly improved, the problems such as edge breakage, corner faults, hidden cracks and fragments in the loading and unloading process of the silicon wafers can be effectively solved, the loading and unloading time is shortened, the quality of battery pieces is improved, and the qualified rate of the battery pieces is increased.

Description

technical field [0001] The present invention relates to the technical field related to photovoltaics, in particular to a stacked high-temperature annealing process. Background technique [0002] Among silicon solar cells, monocrystalline silicon solar cells have the highest conversion efficiency and the most mature technology. Monocrystalline silicon cells show excellent performance due to high-quality monocrystalline silicon materials and advanced processing technology. [0003] Among them, diffusion is one of the key processes in the production process of crystalline silicon solar cells. It is to change the surface of P-type silicon wafers into N-type after diffusion, thereby forming a P-N junction, and silicon wafers have photovoltaic effects. Diffusion needs to use a silicon chip holding device to place the silicon chip on the device, and then place the silicon chip carrying device on the carbonization paddle and send it into the diffusion furnace for concentrated diffu...

AI Technical Summary

Problems solved by technology

A qualified quartz boat is very expensive to manufacture, and the silicon wafer carrying device made of quartz products has the disadvantage of being fragile

The commonly used quartz boat is a frame structure surrounded by four horizontal bars and four vertical bars. There are silicon chip slots on the four horizontal bars, and the silicon chips are inserted in the slots at intervals. A vertical rod is the four supporting feet of the whole quartz boat. The supporting feet of the quartz boat are under too much pressure and are easily damaged, resulting in a short service life of the whole quartz boat.

At the same time, the two handles on the quartz boat will often introduce pollutants when placing the silicon wafers, so that the pollutants will be mixed into the silicon wafers during diffusion, resulting in color difference in the produced cells

[0004] The production process of traditional crystalline silicon cells with thermal oxidation process is: texturing→phosphorus diffusion→etching→thermal oxidation→PECVD coating→printing and sintering. The thermal oxidation adopts the method of inserting quartz boats, and the spacing between each silicon chip is 2.38- 4.76mm, the silicon wafer is in direct contact with the air, the surface is easily polluted, and the produced cells are prone to adverse conditions such as color difference and black spots under the EL

In addition, when the quartz boat is used in the high-temperature annealing process, there are complex operations, long time-consuming, and problems such as chipping, hidden cracks, and debris during the loading and unloading process, which affect the quality of the cell.

Images