The entire process of cleaning the quartz tube should strictly follow the relevant process safety standards of the diffusion process.

If there is a previously used hydrofluoric acid solution in the cleaning tank, an additional 10 bottles of hydrofluoric acid can be added (prepared by production personnel) if the solution is not dirty; If the original hydrofluoric acid solution is very dirty, it should be completely emptied and the tank cleaned, and then the production personnel should be notified to prepare the solution; If there is no remaining hydrofluoric acid solution in the tank, please ask the production personnel to prepare the solution after washing the tank.

3. The cleaning personnel must wear protective glasses and acid resistant gloves, and then place the spare quartz tube into the slot near the quartz tube cleaning machine, with the tube mouth facing the velvet making room and the tube tail pointing towards the direction of the diffusion furnace. Pull down the protective door, set the acid tank cleaning time to 30 minutes, and press the "Acid Tank Start" button on the control panel.

4. Setting of acid tank cleaning time:

The new quartz tube only needs to be cleaned for about 30 minutes. If it is a used quartz tube, the time to remove all the white phosphorus pentoxide adhered to the inner wall of the tube should be taken as the standard. Cleaning used pipes can take one to two days. When the acid tank is not started, the quartz tube should be rotated 180 ° every 2 hours.

5. The cleaning personnel should wear protective glasses and gloves, take out the quartz tube from the acid tank, and gently place it in the sink. Empty the water in the sink and rinse the inner and outer walls of the quartz tube with a water gun for about 5 minutes. When flushing the inner wall of the quartz tube, do not press the "sink start" button. If it has already been pressed, press the "sink end" button again. Then pull the water gun to the mouth of the quartz tube and flush the inner wall of the tube from the mouth to the end. When flushing, care should be taken carefully to avoid any areas that have not been flushed. After 2 minutes, rotate the quartz tube 180 ° and rinse in the same way for 2 minutes.

6. Inject pure water into the sink, with the water level reaching the middle vent pipe at the end of the quartz tube. Pull down the protective door, set the cleaning time of the sink to 30 minutes, and press the "sink start" button.

7. Repeat step 6 and clean again.

After the sink is completed, drain the water from the sink. Then, follow the method in step 5 above to rinse the inner/outer walls of the quartz tube with a water gun. Mainly flush the inner wall. After about 5 minutes, rinse the four small ventilation pipes at the end of the pipe with a water gun, which are also the inner walls of the pipe. Rinse for 2 minutes before continuing from the nozzle direction. The cleaning time of this step should not be less than 15 minutes, and the sign of cleaning is that there is no residual granular phosphide on the inner and outer walls of the tube.

9. After cleaning, put the quartz tube at the designated position in the purification room, and put special foam under it.

10. Seal the nozzle and tail pipe with dedicated aluminum foil.