Preparation method of semiconductor device

Abstract

The invention provides a preparation method of a semiconductor device, which comprises the following steps of: providing a substrate, forming a mask layer and a word line penetrating through the masklayer on the substrate, and covering the surface of the mask layer with the word line; and removing part of the word lines in thickness by adopting a chemical mechanical polishing process to expose the mask layer; performing oxidation treatment on the surface of the word line and the surface of the mask layer, and forming an oxide layer on the word line; and removing the oxide layer to obtain theword line with a set thickness. After long-time chemical mechanical polishing process treatment, residual particles which are difficult to clean appear at the joint of the word line and the mask layer, and the surface of the word line also has the problems of recesses and scratches. According to the method for removing the word line after oxidizing the word line, the word line with the set thickness can be obtained, residual particles of the word line can be removed, the problems of scratches, recesses and the like on the surface of the word line can be relieved, and the performance of a semiconductor device is further improved.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for preparing a semiconductor device. Background technique [0002] Chemical Mechanical Polishing (CMP), also known as chemical mechanical polishing, is currently widely used in surface planarization process in semiconductor manufacturing process. The process of chemical mechanical polishing is to put the wafer on the rotating polishing pad, and then apply a certain pressure to grind the wafer with chemical polishing liquid to make the surface of the wafer flat. [0003] In flash memories based on semiconductor technology, some flash memories have higher requirements on the height of word lines. In order to meet their process requirements, chemical mechanical polishing is usually used to adjust the height of word lines. There is a certain height difference from the mask layer on both sides of the word line. However, in the chemical mechanical polish...

AI Technical Summary

Problems solved by technology

However, in the chemical mechanical polishing process, serious depressions will appear on the surface of the word line after long-time grinding, and more material particles will remain at the junction of the surface of the word line and the mask layer, and there will also be particles on the mask layer. Particles of material resulting from some grinding, which are difficult to remove through the cleaning process

In addition, long-term grinding will scratch the surface of the word line, seriously affecting device performance

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