A method for improving memory cell word line chemical mechanical polishing process window

Abstract

A method for improving the chemical mechanical polishing process window of a memory cell word line, comprising: a first step: forming a semiconductor structure with a memory cell word line; a second step: performing a chemical mechanical polishing process on the semiconductor structure; a third step: A hard mask layer is formed on the structure; the fourth step: etching the hard mask layer, so as to form a hard mask covering on the exposed floating gate isolation spacers. In the present invention, in the case where the memory cell word line chemical mechanical polishing process exposes the silicon nitride of the floating gate isolation spacer, since a hard mask covering is formed on the exposed floating gate isolation spacer, the floating gate isolation sidewall is prevented from The walls are etched by a solution such as phosphoric acid, thus effectively improving the memory cell wordline chemical mechanical polishing process window in the case of small wordline critical dimensions.

Description

technical field [0001] The present invention relates to the field of semiconductor manufacturing; specifically, the present invention relates to the field of memory manufacturing; and, more specifically, the present invention relates to a method for improving the chemical mechanical polishing process window of memory cell word lines. Background technique [0002] Chemical mechanical polishing (CMP, chemical mechanical polishing, also called chemical mechanical polishing) is currently widely used in the surface planarization process in the semiconductor manufacturing process. The process of chemical mechanical polishing is to place the wafer on a rotating polishing pad, add a certain pressure, and use chemical polishing liquid to polish the wafer to make the wafer flat. During the process of grinding silicon wafers by chemical mechanical grinding equipment, the abrasive (polishing fluid) flows on the grinding pad through the pipeline, which acts as a lubricant during the grin...

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Problems solved by technology

like image 3 As shown, when the critical dimension of the word line in the subsequent word line chemical mechanical polishing process is small (for example, the critical dimension of the word line is less than 220nm), it will cause the exposed sidewall silicon nitride SiN material (that is, the floating gate isolation side is exposed Wall 41) Problems

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