Common faults and maintenance of CVD equipment

In order to ensure the normal operation of CVD equipment for a long time, in addition to requiring the operator to operate and use the equipment correctly, taking some effective methods to maintain the equipment is the key to protect the normal operation of CVD equipment. Therefore, the following measures can be taken:
(l) Keep the vacuum system of CVD equipment in vacuum state as far as possible. According to the requirements of the deposition process, the process gas and reaction by-products used by CVD equipment are generally highly corrosive.
If the residual reaction gas is not pumped out in time after the deposition of Si3N4 film, it is likely to corrode the gas circuit interface, bellows, vacuum gauge, vacuum pump, etc. Therefore, after the deposition of Si3N4 film, extend the pumping time of the vacuum pump as far as possible to pump out the residual gas as much as possible. When it is not used for several days, start the vacuum pump once to improve the serviceability of the equipment.
(2) Fill nitrogen in time. After the process is completed, the deposited silicon wafers are installed on the quartz boat in the furnace tube. They must be stored in an environment full of nitrogen to prevent oxidation and corrosion, so that they can be better preserved.
(3) Replace the vacuum pump oil regularly. Although the vacuum system used is equipped with a vacuum pump oil filter, it can keep the pump oil clean for a long time. However, for the reaction system such as sih2c12+nh3, as the by-product NH4Ci white powder is generated at both ends of the furnace tail and the furnace mouth during the reaction, NH4Ci is seriously deposited on the corrugated pipe and vacuum pipe wall at the rear of the reaction pipe. It and HCI and other harmful impurities are in danger of being pumped to the vacuum pump at any time. A small amount of these particles continuously enter the vacuum pump to thicken the pump oil, block the pump oil filtration system and affect the normal operation of the equipment. Therefore, the vacuum pump oil must be replaced regularly.
(4) Regularly repair the solenoid valve. In order to prevent the vacuum pump oil from returning to the vacuum pipe, a solenoid valve is installed on the vacuum pump. The common fault of the solenoid valve is that there is a small amount of NH4Ci powder in the solenoid valve, which reduces the sealing performance of the O-ring in the solenoid valve, resulting in slow leakage in the vacuum system. The vacuum system of the whole equipment can not maintain the vacuum state after shutdown. Only the solenoid valve is regularly repaired, After cleaning, replace the O-ring in the solenoid valve, so that the vacuum system of CVD equipment can be in a vacuum state after the film deposition is completed.