Method for forming gate channel and corresponding semiconductor structure

Abstract

The present invention relates to the field of three-dimensional device fabrication, and in particular to a method for forming a gate channel and a corresponding semiconductor structure. By pre-burying an alignment mark in a stack structure, depositing a hard mask layer and etching it so that the hard mask layer is at least Covering is located above the alignment mark; then depositing a light-absorbing film and etching it so that the light-absorbing film has an opening above the alignment mark; then performing an alignment measurement, marking the gate channel corresponding to the alignment mark on the hard mask layer The to-be-etched mark; and then etch according to the to-be-etched mark to form a gate channel. In the present invention, by opening the light-absorbing film above the alignment mark, the incident light can be smoothly penetrated and reflected during the alignment measurement, so that the position of the alignment mark can be accurately measured, so as to ensure the accuracy of the grid when the channel is etched. Precise transfer of patterns.

Description

technical field [0001] The invention relates to the field of three-dimensional device fabrication, in particular to a method for forming a gate channel and a corresponding semiconductor structure. Background technique [0002] In the prior art, when producing a stacked memory to form a gate channel, it is usually necessary to deposit a thicker hard mask layer on top of the stacked structure (such as an alternately stacked 39-layer oxynitride layer) as an anti-reflection in the photolithography process. layer to ensure the morphology and critical dimensions of the gate channel after etching. [0003] However, when the thickness of the anti-reflection layer reaches a certain level (usually this thickness is much smaller than the thickness that can ensure the shape of the gate channel and the thickness of the key dimensions), it has a very high light absorption rate, and it cannot transmit light, which leads to the alignment used for etching. quasi-markers cannot be measured. ...

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Problems solved by technology

[0005] In view of the above-mentioned technical problems, the present invention aims to provide a method for forming a gate channel and a corresponding semiconductor structure to solve the problem in the prior art that the alignment mark cannot be measured due to the thick Kodiak film, which leads to subsequent channel etching. When the gate pattern cannot be precisely aligned

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