Acid adding method and device for stokehole cleaning machine

Abstract

The invention discloses an acid adding method and device for a stokehole cleaning machine. The acid adding method and device has the advantages that by changing the flow type acid adding into the liquid level type acid adding, accuracy of acid prepared liquor amount is increased, acid concentration ratio error is reduced, the risks of silicon wafer burning and furnace tube and silicon wafer clamping tool pollution caused by unclean washing is reduced, and chemical waste is reduced, utilization rate of chemicals is increased. In addition, the method and device is widely applicable to various solution proportioning.

Description

technical field [0001] The invention relates to a furnace cleaning machine in a crystalline silicon solar ultra-clean workshop, in particular to a method for adding acid to a furnace cleaning machine and a device thereof. Background technique [0002] At present, in the production process of solar cells, in order to prevent the silicon wafers from being scorched due to impurities during high-temperature diffusion, which will affect the quality of the silicon wafers, the silicon wafers are cleaned by a furnace cleaning machine before diffusion, and the furnace cleaning machine mainly Wash with HCL and HF solution to remove impurities and metal ions in the silicon wafer. In order to ensure the cleaning effect, the proportion of the solution must be ensured. Too much acid will easily cause the silicon wafer to be corroded too much. A large area of ​​the surrounding silicon wafers is scorched, which will seriously pollute the furnace tube of the diffusion furnace. In order to ...

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Problems solved by technology

In order to ensure the cleaning effect, the proportion of the solution must be ensured. Too much acid will easily cause the silicon wafer to be corroded too much. A large area of ​​the surrounding silicon wafers is scorched, which will seriously pollute the furnace tube of the diffusion furnace

In order to ensure the ratio of acid concentration, it must be confirmed that the amount of acid added is constant. The traditional method of acid replenishment is: when the flow rate of acid liquid is constant, the amount of acid added is controlled by controlling the opening and closing time of the valve and the fluid replenishment coefficient. The way of adding acid is easily affected by the flow rate. In actual operation, the flow rate of acid liquid cannot be uniform. This method of adding acid has a large error

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