Method for forming micro-graphic pattern on floating grid

Abstract

The invention provides a method for forming micro-fine patterns on a floating grid, comprising the steps as follows: a multi-crystal silicon layer and a photoresist layer are sequentially formed on a silicon substrate where a floating grid is formed; the photoresist layer is exposed and developed; thermal reflux is carried out to the obtained photoresist patterns; by controlling the reflux temperature and the reflux time, the photoresist patterns with prearranged wire width and spacing are obtained; subsequently, the photoresist patterns with the prearranged wire width and the spacing is transferred to the multi-crystal silicon layer so as to carry out the subsequent preparation. By the method of the invention, patterns with the spacing of 80nm and less than 80nm on the floating grid, which can only be obtained by the more advanced ArF(ASML PAS / 1150C) scanner and ArF photoresist, can be obtained only by adopting the KrF(ASML PAS / 850c) scanner and thermal reflux KrF photoresist; furthermore, by comparison, the preparation process tolerance is more.

Description

technical field [0001] The invention relates to a method related to the manufacture of a non-flash memory, especially a method for manufacturing a fine pattern on a floating gate. Background technique [0002] For NAND flash memory, it is necessary to make a pattern with 80nm spacing / 0.22μm line width on the floating gate. [0003] The traditional method is to sequentially form a polysilicon layer, a silicon nitride layer, and a photoresist layer on the substrate; To complete the formation of the photoresist pattern; then etch the silicon nitride layer, and then etch the polysilicon layer using the silicon nitride as a mask to form a line interval much larger than 80nm. The line spacing is then narrowed to 80nm by forming polysilicon spacers. [0004] However, due to the limitation of the resolution of the 248nm KrF scanner, the current photolithography technology for forming lines and spaces on floating gates cannot achieve line spacing of 80nm or below through the tradit...

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Problems solved by technology

[0004] However, due to the limitation of the resolution of the 248nm KrF scanner, the current photolithography technology for forming lines and spaces on floating gates cannot achieve line spacing of 80nm or below through the traditional 248nm KrF process, so it cannot meet the required development. Requirements for post-inspection critical dimensions

[0005] Although 193nm ArF can be done, its cost is relatively high and its process tolerance is small

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