Method for controlling CD during an etch process
AssigneeSamsung Electronics Co., Ltd.
InventorsMyeong-Cheol Kim, Yong-Hoon Kim, Jeong-Yun Lee
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Abstract
A method for controlling CD of etch process defines difference between designed dimension and etched dimension as dimensional displacement and defines target value of the dimensional displacement. A plurality of samples are prepared in each group having different exposure ratios. The plurality of samples of each group are etched until etch end point is detected and then over-etched for uniform time interval after detecting the etch end point. Using etch end point and over-etch time, correlation function of the over-etch time to the etch end point time is determined and the over-etch time to the etch end point is determined using the correlation function.
Claims9
A method for controlling a critical dimension, comprising:
- defining a difference between a designed dimension and an etched dimension as a dimensional displacement;
- specifying a target value of the dimensional displacement;
- preparing a plurality of samples classified into groups according to exposure ratio;
- etching the samples of each group until an etch end point is detected and over-etching the samples of each group for different times according to a uniform time interval;
- selecting an end point detection time and an over-etch time of each group according to the target value of the dimensional displacement;
- determining a correlation function of end point time to over-etch time;
- and
- determining an over-etch time corresponding to the end point time using the correlation function.
Dependencies are inferred from the claim text.