METHOD OF DETECTING END POINT OF PLASMA ETCHING PROCESS
First Claim
1. 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 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.
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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
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.
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Citations
20 Claims
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1. 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 Lm′
(t) {=d[Lm(t)]/dt} and Ls′
(t) {=d[Ls(t)]/dt} and plot the same with the time; andidentifying at least one etching end-point from the plot of the one index with the time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of detecting an end point of a plasma etching process for etching a first layer on a second layer comprising 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:
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collecting respective time-dependent intensities of spectral lines of N (≧
2) groups caused by the first and the second etching products in an emission spectrum of the plasma, wherein the k-th group among the N groups includes a number “
m(k)”
[m(k)≧
1] of spectral line(s) of the first etching product having intensity “
Ik,j=1 to m(k)(t)” and
a number “
n(k)”
[n(k)≧
1] of spectral line(s) of the second etching product having intensity “
Ik,i=1 to n(k)(t)”
, and “
m(k)+n(k)≧
3”
is satisfied;calculating, in real time, one index of Lm(t) Lm′
(t) {Lmk′
(t)=d[Lmk(t)]/dt} and Ls′
(t) {Lsk′
(t)=d[Lsk(t)]/dt} for each group among the N groups and plot the same with the time; andidentifying at least one etching end point from the plots of the one index with the time respectively for the N groups. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification