Method for controlling a recess etch process
First Claim
1. A method of controlling a recess etch process, comprising:
- for a multilayered substrate having a trench therein and a column of material deposited in the trench, determining a first dimension from a surface of the substrate to a reference point in the substrate by;
obtaining a measured net reflectance spectrum of at least a portion of the substrate including the trench;
computing a modeled net reflectance spectrum of the portion of the substrate as a weighted incoherent sum of reflectances from n≧
1 different regions constituting the portion of the substrate;
determining a set of parameters that provides a close match between the measured net reflectance spectrum and the modeled net reflectance spectrum; and
extracting the first dimension from the set of parameters;
computing an endpoint of the recess etch process as a function of the first dimension and a desired recess depth measured from the reference point; and
etching down from a surface of the column of material until the endpoint is reached.
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Abstract
A method of controlling a recess etch process for a multilayered substrate having a trench therein and a column of material deposited in the trench includes determining a first dimension from a surface of the substrate to a reference point in the substrate by obtaining a measured net reflectance of at least a portion of the substrate including the trench, computing a modeled net reflectance of the portion of the substrate as a weighted incoherent sum of reflectances from n≧1 different regions constituting the portion of the substrate, determining a set of parameters that provides a close match between the measured net reflectance and the modeled net reflectance, and extracting the first dimension from the set of parameters; computing an endpoint of the process as a function of the first dimension and a desired recess depth measured from the reference point; and etching down from a surface of the column of material until the endpoint is reached.
37 Citations
19 Claims
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1. A method of controlling a recess etch process, comprising:
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for a multilayered substrate having a trench therein and a column of material deposited in the trench, determining a first dimension from a surface of the substrate to a reference point in the substrate by;
obtaining a measured net reflectance spectrum of at least a portion of the substrate including the trench;
computing a modeled net reflectance spectrum of the portion of the substrate as a weighted incoherent sum of reflectances from n≧
1 different regions constituting the portion of the substrate;
determining a set of parameters that provides a close match between the measured net reflectance spectrum and the modeled net reflectance spectrum; and
extracting the first dimension from the set of parameters;
computing an endpoint of the recess etch process as a function of the first dimension and a desired recess depth measured from the reference point; and
etching down from a surface of the column of material until the endpoint is reached. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of controlling a recess etch process, comprising:
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planarizing a surface of a multilayered substrate having a trench therein and a column of material deposited in the trench;
after planarizing, determining a first dimension from the surface of the substrate to a reference point in the substrate by;
obtaining a measured net reflectance spectrum of at least a portion of the substrate including the trench;
computing a modeled net reflectance spectrum of the portion of the substrate as a weighted incoherent sum of reflectances from n≧
1 different regions constituting the portion of the substrate, wherein the reflectance of each of the n different regions is a weighted coherent sum of reflected fields from k≧
1 laterally-distinct areas constituting the region;
determining a set of parameters that provides a close match between the measured net reflectance spectrum and the modeled net reflectance spectrum; and
extracting the first dimension from the set of parameters;
computing an endpoint of the recess etch process as a function of the first dimension and a desired recess depth measured from the reference point; and
etching down from a surface of the column of material until the endpoint is reached. - View Dependent Claims (18)
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19. A method of controlling a recess etch process, comprising:
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for a multilayered substrate having a trench therein and a column of material deposited in the trench, determining a first dimension from a surface of the substrate to a reference point in the substrate and a second dimension from the surface of the substrate to a surface of the column of material by;
obtaining a measured net reflectance spectrum of at least a portion of the substrate including the trench;
computing a modeled net reflectance spectrum of the portion of the substrate as a weighted incoherent sum of reflectances from n≧
1 different regions constituting the portion of the substrate;
determining a set of parameters that provides a close match between the measured net reflectance spectrum and the modeled net reflectance spectrum; and
extracting the first and second dimensions from the set of parameters;
computing an endpoint of the recess etch process as a function of the first and second dimensions and a desired recess depth measured from the reference point; and
etching down from a surface of the column of material until the endpoint is reached.
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Specification