Contact hole etching method

Abstract

The embodiment of the invention discloses a contact hole etching method, and the method comprises the steps: providing a semiconductor structure which comprises a plurality of stacked control gate structures, forming a step region on at least one side of each control gate structure, and enabling the side wall of a the lower-layer control gate structure in each step region to protrude out of the side wall of an the upper-layer control gate structure, wherein; the semiconductor structure further comprises a dielectric layer covering the step region; forming a hard mask layer on the dielectric layer; defining contact hole patterns in one-to-one correspondence with the control gate structures on the hard mask layer by adopting a first photoetching process; etching the dielectric layer by taking the hard mask layer as a mask so as to form contact holes in one-to-one correspondence with the control gate structures in the dielectric layer; and gradually etching the dielectric layer from the high-layer step region to the low-layer step region, so that the second group of contact holes are deepened until at least part of the surface of the control gate structures is exposed.

Description

technical field [0001] The embodiments of the present application relate to the field of semiconductor manufacturing, and in particular to a contact hole etching method. Background technique [0002] With the continuous development of semiconductor technology, the current memory manufacturing technology has gradually transitioned from a simple planar structure to a more complex three-dimensional structure, and the integration density is increased by three-dimensionally arranging memory cells on the substrate. The technical research and development of this three-dimensional memory device is one of the mainstreams of international research and development. [0003] In the manufacturing process of the three-dimensional memory device, it is necessary to etch and form contact holes on the control gate structures of the step regions in the three-dimensional memory device, and then fill the contact holes, so as to lead out the electrical signals of the control gates. For the forma...

AI Technical Summary

Problems solved by technology

For the formation of contact holes in step regions in three-dimensional memory devices, due to the large number of storage layers in three-dimensional memory devices, the depth of etching needs to become deeper and deeper, and the process of contact hole etching is facing more and more challenges.

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