×

Method for real-time in-situ monitoring of a trench formation process

  • US 5,807,761 A
  • Filed: 07/19/1996
  • Issued: 09/15/1998
  • Est. Priority Date: 07/24/1995
  • Status: Expired due to Fees
First Claim
Patent Images

1. A method for real-time and in-situ monitoring of trench depth and silicon dioxide redeposited layer thickness parameters during a trench formation process on a silicon wafer comprising the steps of:

  • a) placing the wafer in an evacuated reaction chamber of an etching apparatus;

    b) using an oxygen-comprising plasma to etch a desired pattern of trenches in at least a portion of said wafer such that a silicon dioxide layer is redeposited during trench formation;

    c) illuminating an area of said portion with a light beam including at least one first radiation wavelength to produce a reflected interferometric light beam;

    d) applying the reflected light to a spectrometer to generate a primary signal;

    e) processing said primary signal to extract a first secondary signal having a low frequency component and a second secondary signal having a higher frequency component, wherein said first secondary signal is representative of a deposition rate of said silicon dioxide layer, and said second secondary signal is representative of an etch rate of said trenches;

    f) monitoring said silicon dioxide layer deposition with said first secondary signal and a depth of said trenches with said second secondary signal; and

    ,g) in response to said monitoring, stopping the etching when a desired final trench depth has been attained or upon detecting an anomaly in said silicon dioxide layer deposition.

View all claims
  • 0 Assignments
Timeline View
Assignment View
    ×
    ×