Methods for controlling the pressures of adjustable pressure zones of a work piece carrier during chemical mechanical planarization
First Claim
1. A method for removing at least a portion of a material layer from a first surface of a work piece utilizing a CMP apparatus having a work piece carrier with a plurality of pressure adjustable zones, wherein each zone is configured to exert a pressure against a second surface of the work piece during a CMP process, the method comprising the steps of:
- determining a first thickness Tz,n−
1 of the material layer underlying a first zone z, where z is an integer from 1 to Zf, Zf is the total number of zones, n is an integer from 1 to N, and N is the total number of times thickness measurements are assessed;
removing a first portion of the material layer underlying the first zone for a time interval (tn−
tn−
1) wherein the first zone is configured to exert a first pressure Pz,n against the second surface of the work piece;
determining a second thickness Tz,n of the material layer underlying the first zone;
selecting a target thickness Tz,n+1 of the material layer within zone z corresponding to a predetermined thickness profile to be produced before the material layer is substantially removed;
calculating a second pressure Pz,n+1 using the first pressure Pz,n, the first thickness Tz,n−
1, the second thickness Tz,n, and the target thickness Tz,n+1, wherein the second pressure is to be exerted against the second surface of the work piece by the first zone during removal of a second portion of the material layer;
adjusting the pressure exerted by the first zone against the second surface of the work piece to the second pressure Pz,n+1; and
repeating the foregoing steps for a second zone.
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Accused Products
Abstract
Methods are provided for controlling adjustable pressure zones of a CMP carrier. A method comprises determining a first thickness of a layer on a wafer underlying a first zone of the carrier. A first portion of the layer underlying the first zone is removed. The first zone is configured to exert a first pressure against the second surface of the wafer. A second thickness of the layer underlying the first zone is determined and a target thickness corresponding to a predetermined thickness profile is selected. A second pressure for the first zone is calculated using the first thickness, the second thickness, the first pressure, and the target thickness. The pressure exerted by the first zone against the second surface of the wafer is adjusted to the second pressure and the steps are repeated for a second zone.
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Citations
21 Claims
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1. A method for removing at least a portion of a material layer from a first surface of a work piece utilizing a CMP apparatus having a work piece carrier with a plurality of pressure adjustable zones, wherein each zone is configured to exert a pressure against a second surface of the work piece during a CMP process, the method comprising the steps of:
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determining a first thickness Tz,n−
1 of the material layer underlying a first zone z, where z is an integer from 1 to Zf, Zf is the total number of zones, n is an integer from 1 to N, and N is the total number of times thickness measurements are assessed;removing a first portion of the material layer underlying the first zone for a time interval (tn−
tn−
1) wherein the first zone is configured to exert a first pressure Pz,n against the second surface of the work piece;determining a second thickness Tz,n of the material layer underlying the first zone; selecting a target thickness Tz,n+1 of the material layer within zone z corresponding to a predetermined thickness profile to be produced before the material layer is substantially removed; calculating a second pressure Pz,n+1 using the first pressure Pz,n, the first thickness Tz,n−
1, the second thickness Tz,n, and the target thickness Tz,n+1, wherein the second pressure is to be exerted against the second surface of the work piece by the first zone during removal of a second portion of the material layer;adjusting the pressure exerted by the first zone against the second surface of the work piece to the second pressure Pz,n+1; and repeating the foregoing steps for a second zone. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for producing a target thickness profile of a material layer on a first surface of a work piece utilizing a CMP apparatus having a work piece carrier with a number Zf of pressure adjustable zones, wherein each zone is configured to exert a pressure against a second surface of the work piece during a CMP process, the method comprising the steps of:
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for each zone, determining a first thickness Tz,n−
1 of the material layer, where z is an integer between 1 and Zf, n is an integer between 1 and N, and N is the total number of times thickness measurements are assessed;calculating a first average thickness τ
n−
1 of the material layer across the work piece;for each zone, removing a first portion of the material layer, wherein each of said zones is configured to exert a first pressure Pz,n against the second surface of the work piece; for each zone, determining a second thickness Tz,n of the material layer; calculating a second average thickness τ
n of the material layer across the work piece using the second thicknesses;for each zone, selecting a target thickness Tz,n+1 corresponding to the target thickness profile of the material layer; for each zone, calculating a removal rate coefficient Cz,n+1 using the first thickness Tz,n−
1, the second thickness Tz,n, the first average thickness τ
n−
1, the second average thickness τ
n, and the target thickness Tz,n+1; andfor each zone, calculating a second pressure Pz,n+1 from the first pressure and the removal rate coefficient, wherein the second pressure is to be exerted against the second surface of the work piece within the first zone during removal of a second portion of the material layer. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A CMP apparatus comprising:
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a working surface; a work piece carrier configured to press a first surface of a work piece against the working surface, wherein the work piece carrier has a plurality of pressure zones, each pressure zone configured to exert a pressure on a second surface of the work piece; a multi-probe thickness measuring system having a plurality of probes disposed proximate to said working surface, wherein the multi-probe thickness measuring system is configured to measure a thickness of a material layer on the first surface of the work piece; and a controller electrically coupled to the multi-probe thickness measuring system and the work piece carrier, wherein the controller is configured to; receive first signals from the multi-probe thickness measuring system; determine a first thickness of the material layer underlying a first pressure zone of the work piece carrier using the first signals; cause the first zone of the work piece carrier to exert a first pressure against the second surface of the work piece; cause the working surface to remove a first portion from the material layer underlying the first zone; receive second signals from the multi-probe thickness measuring system; determine a second thickness of the material layer underlying the first zone using the second signals; receive as input a target removal amount projected to be removed from the material layer; calculate a second pressure from the first pressure, the first thickness, the second thickness, and the target removal amount; and cause the work piece carrier to change the pressure exerted by the first zone against the second surface of the work piece to the second pressure. - View Dependent Claims (18, 19, 20, 21)
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Specification