Chemical mechanical polishing method capable of enhancing polishing performance

Abstract

The invention provides a chemical mechanical polishing method which can improve the polishing performance. In the prior art, the first polishing period is terminated according to a detected polishingend point, so that the whole polishing process is difficult to control, and the problems of poor polishing performance occur, such as over-polishing recess, corrosion or remained polished layer. The chemical mechanical polishing method comprises a first polishing period and a second polishing period. The pressure of the first polishing period is higher than that of the second polishing period. Themethod comprises the following steps: firstly counting the total time of the first polishing period and the second polishing period; setting the time of the first polishing period to be 60 percent to80 percent of the total time, and conducting the polishing of the first period according to the set time; conducting the polishing of the second period and detecting the polishing end point, and stopping the polishing of the second period when the polishing end point is detected. The invention can greatly improve the controllability of the polishing process, thereby avoiding the phenomena of poorpolishing performance, such as over-polishing recess, corrosion or remained polished layer.

Description

technical field [0001] The invention relates to chemical mechanical polishing technology, in particular to a chemical mechanical polishing method capable of improving polishing performance. Background technique [0002] After making tungsten plugs, copper metal lines and shallow trench isolation structures, it is necessary to remove the useless tungsten, copper and trench fillers that affect the surface morphology of the wafer through chemical mechanical polishing (CMP). Removal to planarize the wafer, CMP for tungsten, copper, and shallow trench fill now includes first-stage polishing and second-stage polishing, the pressure of the first-stage polishing is greater than that of the second-stage polishing, the first-stage and In the second stage of polishing, the polishing is terminated according to the detected polishing end point. The CMP machine uses copper, tungsten, and trench fillers that are different from the reflectivity of the underlying insulating dielectric layer ...

AI Technical Summary

Problems solved by technology

[0003] However, the above-mentioned high-pressure first-stage polishing stops polishing according to the detected polishing end point, which is likely to cause poor polishing performance, such as excessive dishing and erosion. Therefore, it is necessary to reduce the first-stage high Time for pressure polishing

However, too short a polishing time in the first stage will result in insufficient polishing and leave residues of tungsten, copper and trench fill

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