Method for determining an endpoint and semiconductor wafer
First Claim
1. A method for determining an endpoint during chemical-mechanical polishing of a semiconductor wafer, comprising the steps of:
- providing the semiconductor wafer;
depositing a first layer over the semiconductor wafer, wherein the first layer has a first portion on a second portion;
depositing, on the first layer, a sacrificial layer, wherein the physical properties of the sacrificial layer are different from the physical properties of the first layer;
polishing the semiconductor wafer to remove the sacrificial layer and the first portion of the first layer; and
detecting a variation of the physical properties between the sacrificial layer and the first layer when polishing reaches the first layer;
determining an endpoint on the basis of the variation;
depositing a third layer on the sacrificial layer, wherein the physical properties of the sacrificial layer are different from the physical properties of the third layer; and
removing the third layer during polishing.
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Abstract
A method for determining an endpoint during chemical-mechanical polishing of a semiconductor wafer (100, 200) is disclosed. The method comprises the steps of depositing on a first layer (106, 206) to be polished a second layer (108, 208), the physical properties of the first layer (106, 206) being different from the physical properties of the second layer (108, 208). After that, the wafer (100, 200) is polished by chemical-mechanical polishing. Due to the different physical properties of the layers, a variation of the physical properties can be detected, and an endpoint can be determined on the basis of the detected variation. Further, a semiconductor wafer for use in a chemical-mechanical polishing process is disclosed.
27 Citations
15 Claims
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1. A method for determining an endpoint during chemical-mechanical polishing of a semiconductor wafer, comprising the steps of:
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providing the semiconductor wafer;
depositing a first layer over the semiconductor wafer, wherein the first layer has a first portion on a second portion;
depositing, on the first layer, a sacrificial layer, wherein the physical properties of the sacrificial layer are different from the physical properties of the first layer;
polishing the semiconductor wafer to remove the sacrificial layer and the first portion of the first layer; and
detecting a variation of the physical properties between the sacrificial layer and the first layer when polishing reaches the first layer;
determining an endpoint on the basis of the variation;
depositing a third layer on the sacrificial layer, wherein the physical properties of the sacrificial layer are different from the physical properties of the third layer; and
removing the third layer during polishing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
the second portion of the first layer has a second height and the second height is greater than the first height.
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14. A method according to claim 13, wherein the third layer is a metal and the first layer is an oxide.
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15. A method according to claim 13, wherein the third layer has an opening and depositing the first layer further comprises depositing the first layer within the opening.
Specification