Method for controlling etch rate when using consumable electrodes during plasma etching
First Claim
1. A method for controlling etching rate for semiconductor substrates during a plasma assisted chemical etching process when using a consumable upper electrode and a non-consumable lower electrode to extend process selectivity comprising the steps of:
- a) providing a first pressure manometer to measure chamber pressure in the vicinity of the lower non-consumable electrode;
b) providing a second pressure manometer to measure a gap pressure between the upper consumable and lower non-consumable electrode;
c) providing automatic means for adjusting the upper consumable electrode to maintain a fixed gap dimension intermediate the upper consumable and lower non-consumable electrodes;
d) establishing process parameters using feedback from the first and second pressure manometers;
e) establishing an ideal gap dimension intermediate the upper consumable and lower non-consumable electrodes as a reference point to adjust to and compensate for wearing away of the consumable upper electrode; and
f) automatically adjusting the gap dimension and the chamber pressure by either on-line or off-line options.
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Abstract
A method and apparatus to improve process control during plasma etching of semiconductor substrates. Improvements are directed towards controlling the rate of etching when using consumable electrodes. Consumable electrode materials are used to increase selectivity in certain plasma etching processes as in via. contact. or in SOG etch. A consumable electrode material has a significant effect on processing time due to changing gap dimension between electrodes. This invention teaches how to adjust for process variables by using feedback from two strategically placed pressure manometers.
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Citations
6 Claims
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1. A method for controlling etching rate for semiconductor substrates during a plasma assisted chemical etching process when using a consumable upper electrode and a non-consumable lower electrode to extend process selectivity comprising the steps of:
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a) providing a first pressure manometer to measure chamber pressure in the vicinity of the lower non-consumable electrode; b) providing a second pressure manometer to measure a gap pressure between the upper consumable and lower non-consumable electrode; c) providing automatic means for adjusting the upper consumable electrode to maintain a fixed gap dimension intermediate the upper consumable and lower non-consumable electrodes; d) establishing process parameters using feedback from the first and second pressure manometers; e) establishing an ideal gap dimension intermediate the upper consumable and lower non-consumable electrodes as a reference point to adjust to and compensate for wearing away of the consumable upper electrode; and f) automatically adjusting the gap dimension and the chamber pressure by either on-line or off-line options. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification