Method and apparatus for in-situ end-point detection and optimization of a chemical-mechanical polishing process using a linear polisher
First Claim
1. A chemical mechanical polishing element comprising a belt comprising a layer of polishing material, the belt formed in a closed loop and being at least partially comprised of a layer of material substantially transparent to light within a selected range of optical wavelengths and adapted to flex as the belt moves in use.
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Abstract
A linear polishing belt for use in chemical-mechanical polishing (CMP) of a substrate comprises an opening and a flexible monitoring window secured to the belt to close the opening and to create a monitoring channel in the belt. A plurality of monitoring channels can also be used. A film thickness monitor comprising an interferometer can be disposed alongside the belt or at least partially within a region bound by it. The monitoring channel and the film thickness monitor can be used in the CMP process to determine the end point of the CMP process, determine removal rate at any given circumference of a substrate, determine average removal rate across a substrate surface, determine removal rate variation across a substrate surface, and optimize removal rate and uniformity.
107 Citations
20 Claims
- 1. A chemical mechanical polishing element comprising a belt comprising a layer of polishing material, the belt formed in a closed loop and being at least partially comprised of a layer of material substantially transparent to light within a selected range of optical wavelengths and adapted to flex as the belt moves in use.
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7. In a linear chemical mechanical polishing device of the type comprising:
- at least two rollers;
a belt comprising a layer of polishing material and mounted to extend between the rollers such that rotation of the rollers drives the belt; and
a substrate carrier positioned adjacent the belt to press a substrate into contact with the belt intermediate the rollers;
the improvement comprising the belt being at least partially comprised of a layer of material substantially transparent to light within a selected range of optical wavelengths and adapted to flex as the belt moves around and between the rollers in use. - View Dependent Claims (8, 9, 10, 11, 12, 16, 17, 18, 19)
- at least two rollers;
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13. A method of optimizing a chemical-mechanical polishing process comprising:
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(a) providing a belt having an opening formed therein and a monitoring window secured to the belt to close the opening and to create a monitoring channel in the belt the monitoring window comprising a flexible material adapted to flex with the belt as the belt moves in use;
(b) determining a removal rate of a substrate undergoing chemical-mechanical polishing by the belt; and
then(c) adjusting polishing process parameters to optimize the removal rate. - View Dependent Claims (14, 15, 20)
(d) determining removal rate variation; and
then(e) adjusting polishing process parameters to optimize uniformity.
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15. The invention of claim 13, wherein the flexible material comprises urethane.
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20. The invention of claim 13, wherein removal rate is determined in (b) using a film thickness monitor disposed adjacent the belt.
Specification