Methods of and apparatuses for controlling process profiles

• US 7,403,834 B2
• Filed: 09/14/2005
• Issued: 07/22/2008
• Est. Priority Date: 05/08/2003
• Status: Expired due to Term

• Current Assignee: KLA-Tencor Corporation
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Poolla, Kameshwar, Spanos, Costas J.
• Primary Examiner(s): Cabrera; Zoila E
• Application Number:
  US11/228,004
• Publication Number:
  US 20060089740A1
• Time in Patent Office: 1,042 Days
• Field of Search: 700/121, 700/109, 700/110, 438/5, 438/7, 438/14, 702/81, 702/84
• US Class Current: 700/121
• CPC Class Codes: H01L 22/10 Measuring as part of the manufacturing process burn-in G01R31/2855
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

Presented are methods and apparatus for controlling the processing of a substrate during a process step that is sensitive to one or more process conditions. One embodiment includes a method performed with corresponding apparatus that includes a controller. One step includes constructing a perturbation model relating changes in control parameters for the apparatus to one or more resulting changes in the process. The method also includes the step of using the perturbation model with at least one of a performance objective and a constraint to derive optimized control parameters for the controller. Another step in the method includes operating the controller with the optimized control parameters. Another embodiment includes an apparatus for processing substrates where the apparatus comprises optimized control parameters.

Claims

1. A method of adjusting a profile of process conditions of a substrate during processing, the method being performed using a process apparatus and a controller, the controller and process apparatus being coupled so the controller is capable of controlling the profile of process conditions experienced by the substrate, the controller being capable of using at least one control parameter, the method comprising:

i. constructing a perturbation model for the process apparatuses that relates changes in the at least one control parameter to resulting changes in the profile of process conditions, wherein the perturbation model represents the operation of the process apparatus, and wherein constructing the perturbation model comprises;

a) measuring baseline values of the process conditions comprising spatially resolved and time resolved conditions;

b) conducting a series of designed experiments to obtain data to construct the perturbation model; and

c) using the data to construct the perturbation model and to estimate basis functions to complete the perturbation model;

ii. using the perturbation model with at least one of

a performance objective and

a constraint

to derive optimized control parameters; and

iii. operating the controller with the optimized control parameters.

2. The method of claim 1 wherein the process comprises a process used for fabricating integrated circuits on semiconductor wafers.

3. The method of claim 1 wherein the process is selected from the group consisting of photolithography, plasma etch, chemical vapor deposition, thermal anneal, ion implantation, post exposure bake, and physical vapor deposition.

4. The method of claim 1 wherein the perturbation model comprises a linear model for small changes in the profile of process conditions.

5. The method of claim 1 wherein the perturbation model comprises a nonlinear model for large changes in a spatial and temporal profile of process conditions.

6. The method of claim 1 wherein the optimized control parameters are derived using the performance objective and the constraint.

7. The method of claim 1 wherein the process includes a transient regime and a near steady-state regime and the optimized control parameters are derived in order to optimize at least one of

the transient regime and

the near steady-state regime.

8. The method of claim 1 wherein the substrate sensitive process includes a transient regime and a near steady-state regime and the optimized control parameters are derived in order to optimize the transient regime.

9. The method of claim 1 wherein the process includes a transient period and a near steady-state regime and the optimized control parameters are derived in order to optimize the near steady-state regime.

10. The method of claim 1 wherein step iii comprises

a) measuring an initial conditions profile of time resolved and spatially resolved data;

b) providing a predetermined performance objective and a constraint;

c) calculating adjustments for the control parameters using the initial profile, the performance objective, the constraint, and the perturbation model; and

d) adjusting the control parameters in the controller and using the adjustments so as to provide the optimized control parameters.

11. The method of claim 1 wherein the spatial and temporal profile comprises at least one of temperature, plasma potential, ion energy, ion density, and heat flux for the substrate in a glow discharge plasma process.

12. The method of claim 1 wherein the spatial and temporal profile comprises temperature of the substrate in a glow discharge plasma process.

13. The method of claim 1 wherein the substrate is selected from the group consisting of semiconductor wafer, flatpanel display, and photolithography mask.

14. The method of claim 1 wherein the performance objective comprises matching a predetermined temperature profile and the predetermined temperature profile optimizes the critical dimensions for the substrate.

15. The method of claim 1 wherein the performance objective comprises a critical dimension uniformity.

16. The method of claim 1 wherein the performance objective comprises matching a predetermined temperature profile, the predetermined temperature profile provides uniformity results so that the uniformity for the overall processing of the substrate is optimized.

17. The method of claim 1 wherein the performance objective comprises matching a predetermined temperature profile, the predetermined temperature profile provides uniformity results so that a combination of the uniformity results with uniformity results for other processing steps produce a higher degree of uniformity for the overall processing of the substrate.

18. A method of adjusting a spatial and temporal profile of process conditions of a substrate during processing, the method being performed using a process apparatus and a controller, the controller and process apparatus being coupled so the controller is capable of controlling the spatial or temporal profile of process conditions experienced by the substrate, the controller being configured for using at least one control parameter, the method comprising:

i. constructing a perturbation model for the process apparatus that relates changes in the at least one control parameter to resulting changes in a metric, wherein the perturbation model represents the operation of the process apparatus, and wherein constructing the perturbation model comprises;

a) measuring baseline values of the process conditions comprising spatially resolved and time resolved conditions;

b) conducting a series of designed experiments to obtain data to construct the perturbation model; and

c) using the data to construct the perturbation model and to estimate basis functions to complete the perturbation model;

ii. using the perturbation model with at least one of

a performance objective and

a constraint

to derive optimized control parameters; and

iii. operating the controller with the optimized control parameters.

19. The method of claim 18 wherein the substrate comprises a wafer for semiconductor device manufacturing and the metric comprises critical dimension.

20. The method of claim 18 wherein the substrate comprises a lithography mask for semiconductor device manufacturing and the metric comprises critical dimension.

21. The method of claim 18 wherein the substrate comprises a wafer for semiconductor device manufacturing and the metric comprises critical dimension uniformity.

22. The method of claim 18 wherein the substrate comprises a lithography mask for semiconductor device manufacturing and the metric comprises critical dimension uniformity.

23. The method of claim 18 wherein the substrate comprises a wafer for semiconductor device manufacturing and the performance objective or the constraint comprises a predetermined critical dimension uniformity.

24. The method of claim 18 wherein the substrate comprises a wafer for semiconductor device manufacturing and the performance objective or the constraint comprises a predetermined critical dimension.

25. A method of controlling or adjusting critical dimension profile or critical dimension uniformity of a substrate for semiconductor device manufacturing, the method being performed using a controller that includes at least one control parameter and a process apparatus, the controller and process apparatus being coupled so the controller is capable of controlling spatial profiles or temporal profiles of at least one process condition of the substrate using the at least one control parameter, the method comprising the steps of:

i. constructing a perturbation model for the process apparatus that relates changes in the at least one control parameter to resulting changes in the critical dimension profile or the critical dimension uniformity, wherein the perturbation model represents the operation of the process apparatus and constructing the perturbation model comprises;

a) measuring baseline values of the critical dimension profiles or the critical dimension uniformity comprising spatially resolved and time resolved conditions;

b) conducting a series of designed experiments to obtain data to construct the perturbation model; and

c) using the data to construct the perturbation model and to estimate basis functions to complete the perturbation model;

ii. using the perturbation model with at least one of

a performance objective and

a constraint

to derive at least one optimized control parameter; and

iii. operating the controller with the at least one optimized control parameter.

26. The method of claim 25, wherein the substrate comprises a semiconductor wafer, a lithography mask, or a flat panel display substrate.

27. The method of claim 25, wherein the at least one process condition comprises temperature.

28. The method of claim 25, wherein the at least one process condition comprises heat flux.

29. The method of claim 25, wherein the process apparatus is configured for plasma processing and the at least one process condition comprises at least one of

plasma potential,

ion energy, and

ion density.

30. A computer-readable medium having embodied therein computer readable instructions for deriving at least one optimized control parameter for controlling at least one process condition for processing a substrate, the computer readable instructions comprising:

executable code for a process apparatus perturbation model configured for relating changes in the at least one control parameter to resulting changes in a spatial or a temporal profile of the at least one process condition for the substrate, wherein the perturbation model represents the operation of the process apparatus, and wherein the perturbation model includes

a) measured baseline values of the process conditions comprising spatially resolved and time resolved conditions;

b) data obtained from a series of experiments conducted to construct the perturbation model; and

c) basis functions estimated using the data to construct the perturbation model to complete the perturbation model;

executable code for receiving or storing at least one of

a performance objective and

a constraint; and

executable code for deriving the at least one optimized control parameter using the perturbation model and the at least one of

the performance objective and

the constraint.

31. A computer program product for deriving at least one optimized control parameter for controlling critical dimension uniformity for a semiconductor wafer, the computer readable instructions comprising:

executable code for a process apparatus perturbation model configured for relating changes in the at least one optimized control parameter to resulting changes in the critical dimension uniformity for the wafer, wherein the perturbation model represents the operation of the process apparatus, and wherein the perturbation model includes

a) measured baseline values of the process conditions comprising spatially resolved and time resolved conditions;

b) data obtained from a series of experiments conducted to construct the perturbation model; and

c) basis functions estimated using the data to construct the perturbation model to complete the perturbation model;

executable code for receiving or storing at least one of

a performance objective that includes a critical dimension uniformity and

a constraint that includes a critical dimension uniformity; and

executable code for deriving the at least one optimized control parameter using the perturbation model and the at least one of

the performance objective and

the constraint.