Detecting the endpoint of a chamber cleaning
First Claim
1. A method for cleaning a residue accumulated from a prior deposition from a wall within a deposition chamber, comprising the steps of:
- (a) flowing a cleaning gas into the deposition chamber;
(b) forming a plasma of a cleaning gas within the deposition chamber so that at least a portion of the molecules of the cleaning gas are dissociated, wherein the plasma includes one or more reactive species that react with said residue on the wall;
(c) monitoring the intensity of an emission line of a constituent of the partially dissociated cleaning gas;
(d) monitoring the intensity of a background light emission in the chamber;
(e) determining a ratio of the intensity of the cleaning gas emission line to the background emission;
(f) monitoring the determined ratio over time;
(g) comparing the determined ratio to a threshold value; and
(h) controlling the flow of the cleaning gas based on the comparing step.
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Accused Products
Abstract
A method and apparatus for cleaning a CVD chamber including optoelectronic detection of the completion or endpoint of the cleaning procedure once a ratio of emission lines reaches a threshold value. The method comprises the steps of: providing a plasma of a cleaning gas into the chamber and creating a plasma from the cleaning gas. The intensity of emission lines of the cleaning gas and of at least one background gas in the chamber are monitored. A ratio of the intensity of the cleaning gas emission line to the intensity of the background gas emission line is determined and monitored as a function of time. The determined ratio is compared to a preset threshold calibration value. The flow of gas is controlled based on the comparing step. The apparatus includes a cleaning gas supply with a valved inlet providing an entrance to the interior of the chamber for passing cleaning gas to the interior of the chamber. A detector having an optical input is disposed for sensing the electromagnetic radiation. The detector has a first channel for detecting a relative intensity of an emission line corresponding to the cleaning gas and a second channel for detecting a relative intensity of the emission line corresponding to the background gases. Software or circuitry is employed to determine a normalized signal using a signal from the first channel and a signal from the second channel. The value of the normalized signal is substantially invariant with respect to simultaneous corresponding changes in the intensity of the signal measured by the first channel and the intensity of the signal measured by the second channel.
16 Citations
24 Claims
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1. A method for cleaning a residue accumulated from a prior deposition from a wall within a deposition chamber, comprising the steps of:
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(a) flowing a cleaning gas into the deposition chamber;
(b) forming a plasma of a cleaning gas within the deposition chamber so that at least a portion of the molecules of the cleaning gas are dissociated, wherein the plasma includes one or more reactive species that react with said residue on the wall;
(c) monitoring the intensity of an emission line of a constituent of the partially dissociated cleaning gas;
(d) monitoring the intensity of a background light emission in the chamber;
(e) determining a ratio of the intensity of the cleaning gas emission line to the background emission;
(f) monitoring the determined ratio over time;
(g) comparing the determined ratio to a threshold value; and
(h) controlling the flow of the cleaning gas based on the comparing step.
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2. A method for cleaning a residue accumulated from a prior deposition from a wall within a deposition chamber, comprising the steps of:
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(a) flowing a cleaning gas into a plasma chamber;
(b) forming a plasma of a cleaning gas within the plasma chamber so that at least a portion of the molecules of the cleaning gas are dissociated, wherein the plasma includes one or more reactive species that react with said residue on the wall;
(c) providing said plasma of the cleaning gas within the deposition chamber;
(d) monitoring the intensity of an emission line of a constituent of the partially dissociated cleaning gas in the deposition chamber;
(e) monitoring the intensity of a background light emission in the deposition chamber, (f) determining a ratio of the intensity of the cleaning gas emission line to the background emission;
(g) monitoring the determined ratio over time;
(h) comparing the determined ratio to a threshold value; and
(i) controlling the flow of the cleaning gas based on the comparing step. - View Dependent Claims (3)
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4. A method for cleaning a residue accumulated from a prior deposition from a wall within a deposition chamber, comprising the steps of:
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(a) providing a plasma of a cleaning gas within the deposition chamber so that at least a portion of the molecules of the cleaning gas are dissociated, wherein the plasma includes one or more reactive species that react with said residue on the wall;
(b) monitoring the intensity of an emission line of a constituent of the partially dissociated cleaning gas;
(c) monitoring the intensity of a background light emission in the chamber;
(d) determining a ratio of the intensity of the cleaning gas emission line to the background emission;
(e) monitoring the determined ratio over time;
(f) comparing the determined ratio to a threshold value; and
(g) determining that the cleaning has reached an endpoint after the determined ratio exceeds the threshold value. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for cleaning a residue accumulated from a prior deposition from a wall within a deposition chamber, comprising the steps of:
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(a) providing a plasma of a cleaning gas within the deposition chamber so that at least a portion of the molecules of the cleaning gas are dissociated, wherein the plasma includes one or more reactive species that react with said residue on the wall;
(b) monitoring a first intensity of an emission line of a constituent of the partially dissociated cleaning gas;
(c) monitoring a second intensity of light transmitted from the interior of the chamber through a neutral density optical filter;
(d) determining a ratio of the first intensity to the second intensity;
(e) monitoring the determined ratio over time;
(f) comparing the determined ratio to a threshold value; and
(g) determining that the cleaning has reached an endpoint after the determined ratio exceeds the threshold value.
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18. A method for cleaning a residue accumulated from a prior deposition from a wall within a deposition chamber, comprising the steps of:
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(a) providing a plasma of a cleaning gas within the deposition chamber so that at least a portion of the molecules of the cleaning gas are dissociated, wherein the plasma includes one or more reactive species that react with said residue on the wall;
(b) monitoring a first intensity of light transmitted from the interior of the deposition chamber through a first optical filter, wherein the first optical filter transmits light only at a characteristic wavelength of a constituent of said partially dissociated cleaning gas;
(c) monitoring a second intensity of light transmitted from the interior of the deposition chamber through a second optical filter, wherein the second optical filter transmits light over a wider range of wavelengths than the first optical filter;
(d) determining a ratio of the first intensity to the second intensity;
(e) monitoring the determined ratio over time;
(f) comparing the determined ratio to a threshold value; and
(g) determining that the cleaning has reached an endpoint after the determined ratio exceeds the threshold value. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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Specification