×

Method of fabricating semiconductor device

  • US 9,847,266 B2
  • Filed: 05/26/2016
  • Issued: 12/19/2017
  • Est. Priority Date: 06/29/2015
  • Status: Expired due to Fees
First Claim
Patent Images

1. A method of fabricating a semiconductor device, the method comprising:

  • forming a stack structure including first-material layers and second-material layers alternately disposed one on another on a substrate, the first-material layers being etchable by etching gas of a first etchant, and the second-material layers being etchable by etching gas of a second etchant;

    forming a mask pattern on the stack structure;

    a first process of etching an upper portion the stack structure using the mask pattern as an etch mask to form an opening through the upper portion of the stack structure,wherein the first process comprises etching respective ones of the first- and second-material layers with the first and second etchants, respectively, generating end point detection (EPD) signals by monitoring first and second etching reaction gases resulting from the etching of said respective ones of the first- and second-material layers, determining end points of the etching of said respective ones of the first- and second-material layers with the first and second etchants from the end point detection (EPD) signals, and using the end points to discern a first set of etch recipes under which said respective ones of the first- and second-material layers have been etched;

    deriving first and second functions of injection times of the first and second etchants, respectively, each with respect to a depth of the opening during the first process; and

    a second process of etching a lower portion of the stack structure using the mask pattern as an etch mask to extend the opening in the upper portion of the stack structure through the lower portion of the stack structure and thereby expose the substrate,wherein the second process comprises creating a second set of etch recipes based on the first and second functions of injection times of the first and second etchants, respectively, and etching respective ones of the first- and second-material layers in the lower portion of the stack structure under the second set of etch recipes,whereby the etch recipes of the first set under which the first- and second-material layers of the upper portion of the stack structure are etched are respectively different from the etch recipes of the second set under which the first and second-material layers of the lower portion of the stack structure are etched,wherein the first process comprisesinjecting the first etchant into a process chamber to etch a nth first-material layer of the stack structure;

    generating a first EPD signal from the first etching reaction gas as the nth first-material layer is etched by the first etchant;

    comparing a value of the first EPD signal with a first reference value;

    stopping the injecting of the first etchant when the value of the first EPD signal is greater than the first reference value, and discerning a nth etch recipe of the first set of etch recipes under which the nth first-material layer was etched using the first etchant up until a time the injecting of the first etchant was stopped;

    storing the nth etch recipe under which the nth first-material layer was etched, in a readable memory;

    injecting the second etchant into the process chamber to etch a mth second-material layer of the stack structure;

    generating a second EPD signal from the second etching reaction gas as the mth second-material layer is etched by the second etchant;

    comparing a value of the second EPD signal with the first reference value;

    stopping the injecting of the second etchant when the value of the second EPD signal is greater than the first reference value, and discerning a mth etch recipe of the first set of etch recipes under which the mth first-material layer was etched using the second etchant up until a time the injecting of the second etchant was stopped; and

    storing the mth etch recipe under which the mth first-material layer was etched, in the readable memory,wherein the first process is terminated when at least one of the values of the first and second EPD signals is less than the first reference value.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×