Method and system for managing semiconductor manufacturing equipment
View Patent ↗A management method capable of making an accurate decision about a malfunction of the semiconductor manufacturing equipment includes sampling a plurality of data of at least one parameter under normal operating conditions of the semiconductor manufacturing equipment; generating a Mahalanobis space A from a group of sampled data; calculating a Mahalanobis distance from measured values of the parameter under ordinary operating conditions of the semiconductor manufacturing equipment; and deciding that a malfunction occurred in the semiconductor manufacturing equipment when the value of the Mahalanobis distance exceeds a predetermined value.
1. A method of controlling semiconductor manufacturing equipment, comprising:
sampling a plurality of data;
generating a correlation matrix based on the plurality of data;
generating an inverse matrix of the correlation matrix in order to generate a Mahalanobis space;
generating a Mahalanobis distance based on the Mahalanobis space; and
generating a control signal which indicates that an operation of the semiconductor manufacturing equipment should be stopped when the Mahalanobis distance exceeds a threshold value.
2. The method of controlling semiconductor manufacturing equipment of claim 1 , wherein the plurality of data is plasma emission intensity.
3. The method of controlling semiconductor manufacturing equipment of claim 1 , further comprising generating an alarm when the Mahalanobis distance exceeds the threshold value.
4. The method of controlling semiconductor manufacturing equipment of claim 1 , further comprising:
standardizing the plurality of data obtained by said sampling to provide standardized data used during said generating a correlation matrix,
wherein said standardizing uses an equation
Y n·m =( Y′ n·m −Ave n )/σ n ,
wherein Y′ n·m is a sample data at an appointed time X n in m time sampling, Ave n is an average of a group of sample data measured at time X n , σ n is a standard deviation of data at time X n , and Y n,m is a standardized sample value at X n ,
whereby n is an integer from 1 to n and m is an integer from 1 to m.
5. The method of controlling semiconductor manufacturing equipment of claim 4 , wherein said generating a correlation matrix uses an equation
r
ij
=
r
ji
=
1
m
∑
p
=
1
m
Y
i
·
p
Y
jp
,
wherein r ij and r ji are matrix elements and i and j are integers from 1 to n.
6. The method of controlling semiconductor manufacturing equipment of claim 5 , wherein said generating a Mahalanobis distance uses an equation
D
2
=
1
n
∑
i
=
1
n
∑
j
=
1
n
a
ij
Y
i
Y
j
,
wherein D is the Mahalanobis distance and a ij are matrix elements of the inverse matrix.
7. The method of controlling semiconductor manufacturing equipment of claim 1 , wherein the threshold value is within a range of 2 to 4.
8. The method of controlling semiconductor manufacturing equipment according to claim 1 , wherein the plurality of data are sampled based on a light intensity of plasma in a reaction chamber.
9. The method of controlling semiconductor manufacturing equipment according to claim 1 , wherein the plurality of data are sampled based on a change in an impedance of a reaction chamber.
10. The method of controlling semiconductor manufacturing equipment according to claim 9 , wherein the change in the impedance is based on a change in a voltage of a high frequency to be supplied to an electrode in the reaction chamber.
11. The method of controlling semiconductor manufacturing equipment according to claim 1 , wherein the plurality of data are sampled based on a voltage, a current and a phase of a supplied high frequency electric power.
12. A semiconductor device produced in accordance with the method of claim 1 .