Apparatus and method for in-situ monitoring of chemical mechanical polishing operations
First Claim
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1. A substrate polishing system comprising:
- a platen which during processing holds a polishing pad;
a polishing head which during processing holds the substrate against the polishing pad on the platen;
an interferometer capable of generating a collimated light beam which during processing is directed at and impinges on a side of said substrate that is being polished, said interferometer generating an interference signal; and
a data processor programmed to compute a measure of uniformity from said interference signal.
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Abstract
An in-situ method of measuring uniformity of a layer on a substrate during polishing of said layer, where the method includes the steps of directing a light beam toward the layer during polishing; monitoring an interference signal produced by the light beam reflecting off of the substrate; and computing a measure of uniformity from the interference signal.
418 Citations
15 Claims
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1. A substrate polishing system comprising:
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a platen which during processing holds a polishing pad; a polishing head which during processing holds the substrate against the polishing pad on the platen; an interferometer capable of generating a collimated light beam which during processing is directed at and impinges on a side of said substrate that is being polished, said interferometer generating an interference signal; and a data processor programmed to compute a measure of uniformity from said interference signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for polishing a substrate, said apparatus comprising:
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a platen which during processing holds a polishing pad, said platen including a passage therethrough; a polishing head which during processing holds the substrate against the polishing pad on the platen; and an interferometer capable of generating a collimated light beam, said interferometer arranged to direct said light beam at least during part of the polishing operation through said passage so that it impinges on said substrate; a window aligned with said passage and through which the light beam passes on its way to the substrate, said window having a diffuse surface receiving the arriving light beam from the interferometer. - View Dependent Claims (11)
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12. A substrate polishing system comprising:
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a platen which during a polishing operation holds a polishing pad; a polishing head which during the polishing operation holds the substrate against the polishing pad on the platen; an interferometer capable of generating a collimated light beam which during the polishing operation is directed at and impinges on a side of said substrate that is being polished, said interferometer generating an interference signal, wherein the interference signal at least for some part of the polishing operation has an amplitude that is cyclical in nature; a display device; and a processor which during the polishing operation receives the interference signal and is programmed to generate therefrom a characterizing waveform which characterizes the polishing operation, said processor further programmed to display the characterizing waveform on the display device for an operator to see, said characterizing waveform presenting data for a period of time that extends over multiple cycles of the interference signal. - View Dependent Claims (13, 14, 15)
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Specification