Chemical Mechanical Polishing Method

Abstract

The invention discloses a chemical mechanical polishing method. The method comprises the following steps: a substrate is subjected to first polishing until the thickness of the edge area of the substrate reaches a first preset value and is smaller than the thickness of the center area of the substrate; the substrate is subjected to second polishing until the thickness of the center area of the substrate reaches a second preset value, wherein the ratio of pressure applied to the edge area to the pressure applied to the center area in the second polishing process is smaller than the ratio of the pressure applied to the edge area to the pressure applied to the center area in the first polishing process; and the substrate is subjected to third polishing, wherein the substrate performs reciprocating motions in the third polishing process. The chemical mechanical polishing method can improve the within-wafer uniformity. Meanwhile, the method does not require modification of existing chemical mechanical polishing equipment, so that the cost can be saved.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a chemical mechanical grinding method. Background technique [0002] Chemical mechanical polishing is a commonly used method to achieve global planarization of the surface, which is a processing technology that combines chemical corrosion and mechanical removal. In the existing chemical mechanical polishing method, the substrate is generally clamped on the grinding head, and a certain pressure is applied to the substrate through the grinding head, so that it is driven by the grinding head to rotate on the grinding disc for grinding. During this process, the grinding rate in the central area of ​​the substrate is basically equal, and as time goes on, the grinding rate in the edge area of ​​the substrate will be greater than that in the central area. For example, when the grinding time reaches 240 seconds, the maximum removal amount of the edge region of the substrate is ap...

AI Technical Summary

Problems solved by technology

For example, when the grinding time reaches 240 seconds, the maximum removal amount of the edge region of the substrate is approximately equal to 1.28 times of the removal amount of the central region. Therefore, it is easy to cause the edge region of the substrate to be thinner than the central region, which affects the substrate Intra-chip uniformity

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