Semiconductor run-to-run control system with missing and out-of-order measurement handling

• US 20030078680A1
• Filed: 10/23/2001
• Published: 04/24/2003
• Est. Priority Date: 10/23/2001
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: PRI Automation, Inc. (Azenta, Inc.)
• Inventors: Edwards, Keith A., Mullins, James A., Zou, Jianping
• Granted Patent: US 6,725,098 B2
• Time in Patent Office: Days
• US Class Current: 700/29
• CPC Class Codes: G05B 13/042 in which a parameter or coefficient is automatically adjusted to optimise the performance
• CPC Class Codes: G05B 13/048 using a predictor
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: G05B 17/02 electric
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps

Abstract

A method for a run-to-run (R2R) control system includes processing materials using a process input and producing a process output, storing the process input in a database, the storing including using a timestamp, storing at least one measurement of the process output in the database aligned with each process input using the timestamp, iterating over the data from the database to estimate a process state, and, if one or more of the measurements is missing from the database, predicting the missing measurements for the database based on a model, and determining an error for calculating a next process input, the error based on the data in the database.

Claims

1. A method for controlling a manufacturing process, includes:

processing using a process input and producing a process output;

storing the process input in a database, the storing including providing a timestamp;

storing at least one measurement of the process output in the database aligned with each process input using the timestamp;

iterating over data from the database to estimate a process state;

if one or more of measurements is missing from the database, predicting the missing measurements for the database based on a model; and

determining an error for calculating a next process input, the error based on the data in the database.

2. The method of claim 1 wherein the database is coupled to one or more modules including at least a sorting module, said sorting module sorting measurements received asynchronously from the process according to the timestamp, the sorted measurements including later arriving measurements, to allow the next process input to be based at least in part by an error calculated using the later available measurements.

3. The method of claim 1 wherein a controller receives the error and produces the next process input.

4. The method of claim 3 wherein the controller comprises one or more of a model-predictive control (MPC) type controller, a direct model inverter type controller, and an integral controller.

5. The method of claim 3 wherein the controller minimizes the error in each run of the process using the estimate of the process state, the estimate of the process state being determined via a model that receives estimations of the missing measurements to determine a next error.

6. The method of claim 1 wherein the process operates on one of a lot or a part of a lot of semiconductor devices.

7. The method of claim 1 wherein the database is coupled to one or more modules that operate on the database.

8. The method of claim 7 wherein the modules include an estimation module, a compute module, a sort module, a pairing module and a data storage module.

9. The method of claim 1 wherein the manufacturing process is a run-to-run (R2R) process for one or more of the following processes:

a chemical-mechanical-planarization (CMP) process, a lithography process and a plasma etching process.

10. A control system includes:

a controller for providing a process input;

a process coupled to the controller to receive the process input and provide a process output;

a database configured to receive the process input and a measurement of the process output, the database capable of aligning each process input and each process output according to a timestamp process;

a model coupled to receive a database output and provide a model output; and

a state estimator coupled to receive the database output and the model output, the state estimator coupled to the controller and configured to provide estimated process inputs based on estimated measurements of the process output corresponding with the aligned process input and process output.

11. The control system of claim 10 wherein the database output includes measurements performed asynchronously from the process, and any, missing measurements, if any, the measurements inserted in an order based on the timestamp process.

12. The control system of claim 10 wherein the database stores the measure of the process output and the estimated measurements of the process output according to a receding horizon filter and the timestamp.

13. The control system of claim 10 wherein the measure of the process output includes a process disturbance via a disturbance transfer function.

14. The control system of claim 10 wherein the process operates on a lot or a part of a lot of semiconductor devices.

15. The control system of claim 10 wherein the controller includes one or more of the following model-predictive control (MPC) type controller, a direct model inverter type controller, and an integral controller.

16. The control system of claim 10, further comprising one or more modules coupled to the database, including at least a sorting module configured to sort measurements received asynchronously from the process according to the timestamp, the sorted measurements including later arriving measurements to allow the next process input to be based at least in part by an error calculated using later available measurements.

17. The control system of claim 10 wherein the control system applies equally to first runs as to subsequent runs.

18. An apparatus includes:

means for processing using a process input and producing a process output;

means for storing the process input in a database, the means for storing including providing a timestamp;

means for storing at least one measurement of the process output in the database aligned with each process input using the timestamp;

means for iterating over the data from the database to estimate a process state;

means for predicting measurements missing from the database based on a model; and

means for determining an error for calculating a next process input wherein the error is based on the data in the database.

19. A computer program product comprising:

signal bearing media having programming adapted to;

process a process input and produce a process output;

store the process input and provide a timestamp, and store at least one measurement of the process output, wherein the at least one measurement is aligned with each process input according to the timestamp;

iterate over the data from the database to estimate a process state;

predict measurements missing from the database based on a model; and

determine an error for calculating a next process input wherein the error is based on the data in the database.