Endpoint detection for semiconductor processes
First Claim
1. A method of etching a layer on a substrate substantially without etching or damaging an underlayer, the method comprising the steps of:
- (a) placing the substrate in a process zone;
(b) providing in the process zone, an energized process gas comprising etchant gas and cleaning gas, to etch the layer on the substrate;
(c) detecting an etching endpoint immediately prior to etching through the entire layer on the substrate; and
(d) changing the composition of the process gas to remove the cleaning gas, to etch the remaining portion of the layer substantially without damaging the underlayer.
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Accused Products
Abstract
A substrate 20 in a process chamber 42 is processed at process conditions suitable for processing a layer 30 on the substrate 20, the process conditions comprising one or more of process gas composition and flow rates, power levels of process gas energizers, process gas pressure, and substrate temperature. The intensity of a reflected light beam 78 reflected from the layer 30 on the substrate 20 is measured over time, to determine a measured waveform pattern. The measured waveform pattern is compared to a pretetermined characteristic waveform pattern, and when the two waveform patterns are similar or substantially the same, the process conditions are changed to change a rate of processing or a process selectivity ratio of the layer 30 on the substrate 20 before the entire layer 30 is completely processed.
260 Citations
34 Claims
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1. A method of etching a layer on a substrate substantially without etching or damaging an underlayer, the method comprising the steps of:
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(a) placing the substrate in a process zone; (b) providing in the process zone, an energized process gas comprising etchant gas and cleaning gas, to etch the layer on the substrate; (c) detecting an etching endpoint immediately prior to etching through the entire layer on the substrate; and (d) changing the composition of the process gas to remove the cleaning gas, to etch the remaining portion of the layer substantially without damaging the underlayer. - View Dependent Claims (2, 3, 4, 5)
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6. A method of processing a substrate while simultaneously cleaning a process chamber, the method comprising the steps of:
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(a) placing a substrate having a layer, into the process chamber; (b) in one process stage, providing an energized process gas into the process chamber to etch the layer on the substrate; (c) in another process stage, providing another energized process gas into the process chamber to etch the layer on the substrate; and (d) during at least one of the process stages, measuring the intensity of radiation reflected from the layer on the substrate to determine a measured waveform pattern, comparing the measured waveform pattern to a predetermined waveform pattern, and changing from one process stage to another process stage, when the measured waveform pattern is substantially the same as the predetermined waveform pattern, wherein the process gas in one of step (b) or (c) comprises a cleaning gas in a volumetric ratio sufficiently high to remove etchant residue deposited on process chamber surfaces. - View Dependent Claims (7)
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8. A method of simultaneously etching a substrate and cleaning an etching chamber, the method comprising the steps of:
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(a) placing the substrate in the etching chamber, the substrate comprising a silicon-containing layer comprising elemental silicon or silicon compounds; (b) providing energized process gas to the etching chamber to etch the silicon-containing layer on the substrate and simultaneously clean the etchant residue formed on chamber surfaces, the energized process gas comprising etchant gas selected from the group consisting of Cl2, HBr, N2, O2, and He--O2, and cleaning gas selected from the group consisting of NF3, CF4, and SF6, the volumetric flow ratio of etchant gas to cleaning gas being selected to remove etchant residue formed on the chamber surfaces upon completion of the etching process; (c) during step (b), measuring an intensity of radiation reflected from the silicon-containing layer on the substrate to determine a measured waveform pattern; and (d) changing process conditions to remove the cleaning gas when the measured waveform pattern is substantially similar to a predetermined characteristic waveform pattern. - View Dependent Claims (9, 10)
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11. A method of processing a substrate in a chamber, the method comprising the steps of:
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(a) placing the substrate into the chamber, the substrate having a layer; (b) processing the layer on the substrate; (c) during step (b), monitoring an intensity of radiation reflected from the layer on the substrate, over time, to obtain a waveform; (d) recognizing a characteristic feature of the waveform that occurs before the layer on the substrate is completely processed; and (e) changing a process condition when the characteristic feature is recognized. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of processing a substrate in a chamber, the method comprising the steps of:
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(a) placing the substrate into a chamber, the substrate having a layer; (b) processing the layer on the substrate; (c) during step (b), monitoring an intensity of radiation reflected from the layer on the substrate to determine a waveform; (d) evaluating the waveform to recognize a characteristic shape; and (e) changing a process condition when the characteristic shape is recognized. - View Dependent Claims (23, 24, 25)
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26. A method of etching a layer on a substrate substantially without etching or damaging an underlayer, the method comprising the steps of:
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(a) placing the substrate in a process zone, and maintaining first process conditions in the process zone to etch the layer on the substrate; and (b) monitoring an intensity of radiation reflected from the layer, and upon recognizing a characteristic feature comprising a change in intensity of the reflected radiation, changing the first process conditions to second process conditions to change a rate of etching of the layer or change an etching selectivity ratio of etching the layer relative to the underlayer, before the entire layer is etched through. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34)
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Specification