Process control by distinguishing a white noise component of a process variance
First Claim
1. A system, implemented on at least one computer, for compensating for a measurement of error between a measured characteristic of at least one product produced by a process and a target result of the characteristic, the system comprising:
- (a) means for receiving at least one observed value for at least one product, and receiving a target value for the at least one product;
(b) means for determining a first measurement of error between the at least one observed value of the at least one product and the target value of the at least one product;
(c) means for determining a white noise portion of the first measurement of error caused by white noise; and
(d) means for using the determined white noise portion to adjust the process to reduce a second measurement of error.
0 Assignments
0 Petitions
Accused Products
Abstract
A method, system and medium is provided for enabling improved control systems. An error, or deviation from a target result, is observed for example during manufacture of semiconductor chips. The error within standard deviation is caused by two components: a white noise component and a signal component (such as systematic errors). The white noise component is, e.g., random noise and therefore is relatively non-controllable. The systematic error component, in contrast, may be controlled by changing the control parameters. A ratio between the two components is calculated autoregressively. Based on the ratio and using the observed or measured error, the actual value of the error caused by the systematic component is calculated utilizing an autoregressive stochastic sequence. The actual value of the error is then used in determining when and how to change the control parameters. The autoregressive stochastic sequence addresses the issue of the effects of run-to-run deviations, and provides a mechanism that can extract the white noise component from the statistical process variance in real time. This results in an ability to provide tighter control, for example in feedback and feedforward variations of process control.
-
Citations
32 Claims
-
1. A system, implemented on at least one computer, for compensating for a measurement of error between a measured characteristic of at least one product produced by a process and a target result of the characteristic, the system comprising:
-
(a) means for receiving at least one observed value for at least one product, and receiving a target value for the at least one product; (b) means for determining a first measurement of error between the at least one observed value of the at least one product and the target value of the at least one product; (c) means for determining a white noise portion of the first measurement of error caused by white noise; and (d) means for using the determined white noise portion to adjust the process to reduce a second measurement of error. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A system, implemented on at least one computer, for compensating for a measurement of error between a measured characteristic of at least one product produced by a process and a target result of the characteristic, the system comprising:
-
(a) a value receiving component for receiving at least one observed value for at least one product, and receiving a target value for the at least one product; (b) a data repository for storing the observed value and the target value; (c) an error determination component configured to determine a first measurement of error between the observed value of at least one product and the target value of the at least one product; (d) a white noise estimator component configured to determine a white noise portion of the first measurement of error caused by white noise; and (e) a process adjustment component configured to adjust the process to reduce a second measurement of error using the determined white noise portion. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
-
-
17. A computer-implemented method for compensating for a measurement of error between a measured characteristic of at least one product produced by a process and a target result of the characteristic, the method comprising:
-
(a) receiving at least one observed value for at least one product, and receiving a target value for the at least one product; (b) determining a first measurement of error between the at least one observed value of the at least one product and the target value of the at least one product; (c) determining a white noise portion of the first measurement of error caused by white noise; and (d) using the determined white noise portion to adjust the process to reduce a second measurement of error. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
-
-
25. A computer program product for use in compensating for a measurement of error between a measured characteristic of at least one product produced by a process and a target result of the characteristic, the computer program product comprising:
-
(a) at least one computer readable medium, readable by the manufacturing process; (b) instructions, provided on the at least one computer readable medium, for receiving at least one observed value for at least one product, and receiving a target value for the at least one product; (c) instructions, provided on the at least one computer readable medium, for determining a first measurement of error between the at least one observed value of the at least one product and the target value of the at least one product; (d) instructions, provided on the at least one computer readable medium, for determining a white noise portion of the first measurement of error caused by white noise; and (e) instructions, provided on the at least one computer readable medium, for using the determined white noise portion to adjust the process to reduce a second measurement of error. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32)
-
Specification