Pressure sensing method for determining gas clean end point
OwnerPen Chen Shihinventor
Life of this patent
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Abstract
A pressure sensing method of detect the end point in a gas cleanup reaction for removing a deposited coating on the interior wall of a low-pressure chemical vapor deposition furnace. The method includes passing a reactive gas into the low-pressure chemical vapor deposition furnace and monitoring a gas pressure inside the furnace. A control factor is varied so that gas pressure inside the furnace remains constant. The degree of variation of the control factor when thickness of the coating is reduced to an acceptable level is set as an end point value. The passage of reactive gas into the low-pressure chemical vapor deposition furnace is stopped as soon as the control factor reaches the end point value.
Claims16
A pressure sensing method of determining an end point during a gas cleaning operation for removing a deposited coating on an interior wall of a low-pressure chemical vapor deposition furnace, the method comprising the steps of:
- passing a reactive gas into the low-pressure chemical vapor deposition furnace;
- monitoring gaseous pressure inside the low-pressure chemical vapor deposition furnace;
- changing a control factor so that gaseous pressure inside the low-pressure chemical vapor deposition furnace remains constant;
- and
- setting a degree of change of the control factor as a value reflecting the reaction end point when thickness of the deposited coating on the interior wall of the furnace is reduced to an acceptable range.
A pressure sensing method of determining an end point during a gas cleaning operation for removing a deposited coating on anthe interior-wall of a low-pressure chemical vapor deposition furnace, the method comprising the steps of:
- passing a reactive gas into the low-pressure chemical vapor deposition furnace;
- monitoring gaseous pressure inside the low-pressure chemical vapor deposition furnace;
- changing a control factor so that gaseous pressure inside the low-pressure chemical vapor deposition furnace remains constant;
- and
- terminating the passage of reactive gas into the low-pressure chemical vapor deposition furnace when thickness of the deposited coating on the interior wall of the furnace is reduced to an acceptable range.
Dependencies are inferred from the claim text.