US 2008/0186473 A1 · METHOD OF DETECTING END POINT OF PLASMA ETCHING PROCESS

Abstract

A method of detecting an end point of a plasma etching process for etching a first layer on a second layer is described, the first layer producing a first etching product and the second layer a second etching product. Time-dependent intensity [Ij=1 to m(t)] of a number “m” (m≧1) of spectral line(s) of the first etching product in emission spectrum of the plasma and that [Ii=1 to n(t)] of a number “n” (n≧1) of spectral line(s) of the second etching product in the emission spectrum are collected, wherein “m+n≧3” is satisfied. One index of Lm  ( t ) [ = ∏ i = 1 , j = 1 n , m  I i  ( t ) I j  ( t ) ] ,  Ls  ( t ) [ = ∏ i = 1 , j = 1 n , m  I i  ( t ) I j  ( t ) ] ,  Lm ′  ( t )  { =  [ Lm  ( t ) ] /  t }   and   Ls ′  ( t )  { =  [ Ls  ( t ) ] /  t } is calculated in real time and plotted with the time. An etching end-point is identified from the plot of the one index with the time.

Claims20

Dependent claims

A method of detecting an end point of a plasma etching process for etching a first layer on a second layer that comprises a material different from that of the first layer, wherein the first layer produces a first etching product and the second layer produces a second etching product, the method comprising:

collecting time-dependent intensity [Ij=1 to m(t)] of a number “m” (m≧1) of spectral line(s) of the first etching product in an emission spectrum of the plasma and time-dependent intensity [Ii=1 to n(t)] of a number “n” (n≧1) of spectral line(s) of the second etching product in the emission spectrum, wherein “m+n≧3” is satisfied;
calculating, in real time, one index of
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Lm′(t) {=d[Lm(t)]/dt} and Ls′(t) {=d[Ls(t)]/dt} and plot the same with the time;
and
identifying at least one etching end-point from the plot of the one index with the time.

69 more elements

Dependencies are inferred from the claim text.

Method of detecting end point of plasma etching process

Life of this patent

Method of detecting end point of plasma etching process

Life of this patent

Abstract

Claims20