Common faults and solutions of multi gas path PECVD

Multiple gas path PECVD (plasma enhanced chemical vapor deposition) equipment may encounter various malfunctions during operation. Here are some common faults and their solutions:

1. Unable to light up
RF power failure: Check if the power output of the RF power source is normal. If it is abnormal, repair or replace the RF power supply.
Low gas intake rate: Check if the gas flow meter is normal. If it is normal, increase the intake rate for testing.
Insufficient cleanliness of the cavity plates: Use a multimeter to measure the ground resistance of the upper and lower plates of the cavity, and the normal value should be above tens of megaohms. If there is an abnormality, clean the cavity plate.
RF matching circuit fault: Check if the reflected power of the RF source is within the normal range. If it is abnormal, check if the capacitors and inductors in the matching circuit are damaged.
Poor vacuum degree: Check if the vacuum degree in the chamber is normal. If it is abnormal, it is necessary to repair the vacuum system or adjust the process parameters.

2. Unstable power supply current
Unstable power supply: Measure whether the power supply is stable. If it is unstable, it is necessary to repair the power supply system or replace the power supply.
Unstable vacuum chamber pressure: Check if the leakage rate of the vacuum system in the chamber is normal, and if the intake volume of the chamber is normal. If there is a problem, it is necessary to repair the vacuum system or adjust the intake volume.
Cable malfunction: Check if the cable contact is good. If there is poor contact, it is necessary to reconnect or replace the cable.

3. Coating quality issues
Poor cleanliness of sample surface: Check if the sample surface is clean. If it is not clean, the sample needs to be cleaned.
Poor cleanliness of the process chamber: Clean the process chamber to ensure that there is no obvious silicon powder or particles on its inner wall.
Abnormal sample temperature: Check if the temperature control system is functioning properly and calibrate the temperature measuring thermocouple. If there is a problem, it is necessary to repair the temperature control system or adjust the temperature parameters.
Abnormal pressure during film deposition process: Check the leakage rate of the chamber vacuum system to ensure that the deposition pressure and gas flow rate are normal and stable.
Unreasonable RF power setting: Check the RF power supply, adjust the set power to ensure normal glow, and ensure that the reflected power is less than 10W.

4. Other common faults
Red chip phenomenon: It may be caused by short sedimentation time, low thinning amount, excessive use of graphite boat, or poor pre-treatment effect. The solution includes adjusting the coating time according to the actual situation, adjusting the coating time in real time based on the situation of the coated film, checking the operation records and confirming the number of times the graphite boat is used, and etching the graphite boat as soon as possible.
Abnormal pre pumping of vacuum chamber: If the vacuum pressure in the chamber does not decrease after turning on the mechanical pump, or if there is a sound of air leakage in the front and rear doors of the deposition chamber (during low vacuum), or if the molecular pump maintains pressure for 20 minutes and rises above 5Pa within half an hour, it may be due to abnormal vacuum chamber or abnormal sealing of the deposition chamber. The solution includes checking the condition of the door and adjusting the door shaft, wiping the area around the sealing ring with alcohol and trying again.

In summary, common faults of multi gas path PECVD equipment involve multiple aspects such as RF power supply, gas flow rate, chamber plate cleanliness, vacuum degree, power supply current stability, coating quality, etc. When solving these faults, it is necessary to investigate and repair them according to specific situations to ensure the normal operation of the equipment and the quality of the coating.