Grid electrode forming method

Abstract

The invention discloses a grid electrode forming method. The grid electrode forming method comprises the steps that a polycrystalline silicon layer is formed on a substrate, a hard mask layer provided with strip-shaped graphs corresponding to the shapes of grid electrodes is formed on the polycrystalline silicon layer, an organic resist layer and an organic anti-reflection material layer are sequentially formed on the hard mask layer, first etching is performed on the organic anti-reflection material layer to form an opening, and second etching is performed on the organic resist layer exposed out from the opening to enable the strip-shaped graphs to be exposed out from the opening; in the second etching process, the first dry etching and the second dry etching which adopt mixed gas including methane are sequentially performed, by adopting the methane to serve as etching gas, the first dry etching has little lateral etching on the organic anti-reflection material layer, and the problem that the opening size is increased is solved; etching is performed on the hard mask layer under the opening, and therefore compared with the design value, the increasing amount of the separation distance of the butt joint direction of finally formed disconnected strip-shaped grid electrodes is small.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for forming a grid. Background technique [0002] Poly Cut technology is used to cut off the strip gate, and the cut gate corresponds to different transistors, which can improve the integration of transistors. In addition, when a plurality of gates are arranged in a row along the extending direction, the pitch in the butting direction between gates that are disconnected after gate cutting can be narrowed with high precision by gate cutting (Poly Cut CD). [0003] In the existing gate cutting process, a polysilicon layer is usually formed on the substrate first, and then a patterned hard mask layer is formed on the surface of the polysilicon layer. The patterned hard mask layer has bar graph. In order to cut off the striped gates, it is necessary to form a patterned photoresist layer on the hard mask layer above the striped pattern, and the patterned photoresi...

AI Technical Summary

Problems solved by technology

[0004] However, in the existing method of forming gates, when the gates are cut off, the distance between the disconnected strip gates in the butt direction tends to increase compared with the design value.

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