Color difference solution for polycrystalline silicon cell texturing

　　The color of the cell sheet is mainly affected by the velvet, the flower sheet, the red sheet and some yin and yang sheets.

　　Red flakes are mainly caused by the low amount of corroded texturing. If the amount of texturing corrosion is less than 3, the damage layer of the silicon wafer will be incompletely removed, resulting in overall redness after PE coating.

　　The so-called flower chip is caused by the excessively high amount of texturing corrosion. Generally speaking, when the amount of texturing corrosion is higher than 4.5, the silicon chip is equivalent to being polished. After coating, the cell is shiny and the grain boundary is also More obvious.

　　For these two phenomena, the main starting point is to control the amount of texturing corrosion, and adjust the process to make the ratio of HNO3 and HF to an ideal, to achieve a better suede effect. The second is to intensify supervision, control the shift before production and monitor the amount of corrosion when the equipment is shut down. During the production process, technicians and quality inspectors are required to check the pile weighing and suede effect several times to ensure the amount of corrosion and the stability of the suede.

　　For the Yin and Yang tablets, it can be divided into the following two situations, one is the immersion situation, and the other is the deviation of the corrosion amount between each channel.

　　The problem of immersion liquid is caused by the level of the front and rear rollers and the front baffle during the production process. When the silicon wafer enters the texturing tank, there is a time difference between the chemical liquid and the silicon wafer. In this way, the area where the silicon wafer first contacts the chemical solution will inevitably have a higher corrosion rate than the area that contacts the chemical solution later. The difference in the amount of corrosion will inevitably lead to inconsistent texture effects on the surface of the silicon wafer, and a certain color difference will occur after PE coating. In order to ensure the immersion effect, the rollers and baffles of the pile making tank need to be adjusted.

　　Specific adjustment method: first readjust the baffle and rollers, level the lower rollers, and lower the rollers as much as possible if possible. When the baffle rises, the height standard is to put the silicon wafer on the front roller of the baffle, press the edge of the silicon wafer with your finger, and the angle of the other side of the silicon wafer is more than 15 degrees. Use this method You can continue to increase the baffle height. From the actual effect, the immersion effect of the silicon wafer can be guaranteed.

　　After adjustment, the silicon wafer immersion liquid is even, which can ensure the same corrosion effect everywhere on the silicon wafer.

　　There is a deviation in the amount of corrosion between the channels, which is mainly caused by the liquid inlet process. Some old equipment has liquid inlet pipes, but the liquid inlet of different pipes is supplied by one pipe, which will cause the least amount of chemical liquid in the inner channel and cause the deviation of the amount of corrosion Some new equipment has a separate liquid inlet pipe, which is porous. Although it can ensure the independence, the liquid inlet is the most problematic. Therefore, a flow limiting device is added to this type of equipment to ensure that the liquid inlet volume is basically the same.

　　In this way, the immersion effect is guaranteed, the deviations are solved, and the yin and yang film caused by the texturing is completely solved.