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CVD furnace equipment Maintenance

CVD furnace equipment Maintenance  
In order to make the normal operation of a long-term CVD equipment, in addition to the requirements of the operator to operate correctly, the use of equipment, take some effective method of maintaining good equipment, it is the key to good CVD normal operation of equipment protection, for which may take the following measures:
(1) as far as possible so that CVD equipment vacuum system in a vacuum state. CVD deposition equipment according to process requirements, the process gas used and the reaction by-products, generally have a strong corrosive. in case Si3N4 film is deposited promptly after completion of the reaction the residual gas is not exhausted, it is likely that the etching gas path interfaces, bellows, vacuum gauge, vacuum pump. Therefore, after the Si3N4 film deposition is completed, try to extend the vacuum pumping time for pumping the residual gas as possible. When not encounter a few days, once turned a vacuum pump, in order to improve equipment in good condition.
(2) timely filling nitrogen. After work completion technology, equipped with a quartz tube furnace is deposited on a silicon wafer boat good, be sure to save it in an environment filled with nitrogen to prevent oxidation, corrosion, so you can better save.

(3) regular replacement of vacuum pump oil. While the vacuum system used to install a vacuum pump oil filter, to keep pump oil clean longer. But for such as SiH2C12 + NH3 reaction system, since the end of the reaction at both ends of the furnace and the furnace mouth generated byproducts NH4CI white powder, NH4CI in the reaction tube rear bellows wall vacuum deposition is quite serious, It and other harmful impurities HCI is drawn at any time to a dangerous vacuum pump. These particles, constantly in small amounts into the vacuum pump, the pump oil thickens, clogging pump oil filtration system, affecting the normal operation of the equipment. Therefore, the vacuum pump oil must be replaced periodically.
(4) regular maintenance solenoid valve. In order to prevent vacuum pump oil return within the vacuum pipe, installed in the vacuum solenoid valve, common faults of the solenoid valve is inside the solenoid valve due to the presence of a small amount of NH4CI powder, so that the sealing performance of the O-ring inside the solenoid valve is reduced, resulting in there is a slow leak the vacuum system, the vacuum system after the shutdown of the entire apparatus can not be maintained in a vacuum state, only regular maintenance solenoid valve, after cleaning replace the O-ring inside the solenoid valve, in order to make the film after completing the deposition vacuum CVD equipment the system is in a vacuum state.
(5) regular cleaning of the quartz tube. In the deposition process on a quartz tube and quartz boat will be deposited on a thin film at the end of each process, the quartz boat should move about in an appropriate place, so as to avoid the buildup quartz boat and quartz tube. With the increase of the production process on a quartz tube and quartz boat increasingly thick deposited film. After reaching a certain level, the emergence of silicon quartz tube cracking phenomenon, but also makes the whole load-bearing quartz tube increased, exceeding its maximum load, a quartz tube a certain degree of subsidence (originally two quartz tube at the same level on). Causing quartz wafer boat tops also followed sink together, deviated from the center position of the furnace tube, causing uneven film deposition. Therefore, in order to ensure regular cleaning process stability and repeatability, thus ensuring product quality.