Differential measurements for endpoint signal enhancement
First Claim
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1. A method for etching a layer, comprising:
- providing a substrate in a chamber;
generating an etch plasma for etching a layer on the substrate;
measuring light from a first region of the chamber to provide a first signal;
measuring light from a second region of the chamber to provide a second signal; and
comparing the first signal with the second signal to determine an etch endpoint,wherein the comparing the first signal with the second signal to determine an etch endpoint indicates a spike in nitrogen in the first region.
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Abstract
A method for etching a layer is provided. A substrate is provided in a chamber. An etch plasma for etching a layer on the substrate is generated. Light from a first region of the chamber is measured to provide a first signal. Light from a second region of the chamber is measured to provide a second signal. The first signal with the second signal are compared to determine an etch endpoint.
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Citations
20 Claims
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1. A method for etching a layer, comprising:
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providing a substrate in a chamber; generating an etch plasma for etching a layer on the substrate; measuring light from a first region of the chamber to provide a first signal; measuring light from a second region of the chamber to provide a second signal; and comparing the first signal with the second signal to determine an etch endpoint, wherein the comparing the first signal with the second signal to determine an etch endpoint indicates a spike in nitrogen in the first region. - View Dependent Claims (2, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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3. The method, as recite in 1, wherein the first region is closer to the substrate than the second region.
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13. An apparatus for etching an etch layer, comprising:
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a plasma processing chamber, comprising; a chamber wall forming a plasma processing chamber enclosure; a substrate support for supporting a wafer within the plasma processing chamber enclosure; a pressure regulator for regulating the pressure in the plasma processing chamber enclosure; at least one electrode for providing power to the plasma processing chamber enclosure for sustaining a plasma; a first light sensor for detecting light from a first region of the plasma processing chamber; a second light sensor for detecting light from a second region of the plasma processing chamber; a gas inlet for providing gas into the plasma processing chamber enclosure; a gas outlet for exhausting gas from the plasma processing chamber enclosure; at least one RF power source electrically connected to the at least one electrode; a gas source in fluid connection with the gas inlet; at least one processor; and computer readable media, comprising; computer readable code for flowing an etch gas from the gas source into the plasma processing chamber; computer readable code for forming a plasma from the etch gas; computer readable code for comparing a first signal from the first light sensor with a second signal from the second light sensor to determine when an etch stop has been reached, wherein the comparing the first signal with the second signal to determine an etch endpoint indicates a spike in nitrogen in the first region or wherein the comparison of the first signal and the second signal indicates that CN from a SiN etch stop layer is present in the first region; and computer readable code for going to a next process after determining that an etch stop has been reached. - View Dependent Claims (14, 15, 16)
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17. A method for etching a layer, comprising:
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providing a substrate in a chamber; generating an etch plasma for etching a layer on the substrate; measuring light from a first region of the chamber to provide a first signal; measuring light from a second region of the chamber to provide a second signal; and comparing the first signal with the second signal to determine an etch endpoint, wherein the comparison of light measured from a first region of the chamber to provide a first signal and light measured from a second region of the chamber to provide a second signal indicates that CN from a SiN etch stop layer is present in the first region. - View Dependent Claims (18, 19)
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20. The method, as recite in 17, wherein the first region is closer to the substrate than the second region.
Specification