Staircase etch control in forming three-dimensional memory device

  • US 10,522,474 B2
  • Filed: 07/26/2018
  • Issued: 12/31/2019
  • Est. Priority Date: 03/08/2017
  • Status: Active Grant
First Claim
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1. A method for controlling a photoresist (PR) trimming rate in a PR trimming process, comprising:

  • forming a PR layer over a first region of a substrate;

    forming a first trimming mark over a second region of the substrate neighboring the first region;

    trimming the PR layer;

    measuring a first distance between the first trimming mark and the PR layer along a first direction parallel to a top surface of the substrate to determine an actual PR trimming rate of the PR trimming process along the first direction;

    comparing the actual PR trimming rate along the first direction with an estimated PR trimming rate along the first direction to determine a first difference between the actual PR trimming rate along the first direction and the estimated PR trimming rate along the first direction; and

    adjusting one or more PR trimming parameters of the PR trimming process based on the first difference.

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