Method of feedback control of sub-atmospheric chemical vapor deposition processes

• US 7,201,936 B2
• Filed: 06/18/2002
• Issued: 04/10/2007
• Est. Priority Date: 06/19/2001
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Schwarm, Alexander T., Shanmugasundram, Arulkumar P., Pan, Rong, Hernandez, Manuel, Mohammad, Amna
• Primary Examiner(s): CHEN, BRET P
• Application Number:
  US10/174,377
• Publication Number:
  US 20030049376A1
• Time in Patent Office: 1,757 Days
• Field of Search: 427/248.1, 427/255.23, 427/8, 427/9
• US Class Current: 427/8
• CPC Class Codes: C23C 16/52 Controlling or regulating the coating process C23C16/45557, C23C16/279 take precedence
• CPC Class Codes: G05B 19/00 Programme-control systems
• CPC Class Codes: G05B 19/19 characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path
• CPC Class Codes: G05B 19/41865 characterised by job scheduling, process planning, material flow
• CPC Class Codes: G05B 2219/32053 Adjust work parameter as function of other cell
• CPC Class Codes: G05B 2219/32065 Synchronise set points of processes
• CPC Class Codes: G05B 2219/45031 Manufacturing semiconductor wafers
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A method of film deposition in a sub-atmospheric chemical vapor deposition (CVD) process includes (a) providing a model for sub-atmospheric CVD deposition of a film that identifies one or more film properties of the film and at least one deposition model variable that correlates with the one or more film properties; (b) depositing a film onto a wafer using a first deposition recipe comprising at least one deposition recipe parameter that corresponds to the at least one deposition variable; (c) measuring a film property of at least one of said one or more film properties for the deposited film of step (b); (d) calculating an updated deposition model based upon the measured film property of step (c) and the model of step (a); and (e) calculating an updated deposition recipe based upon the updated model of step (d) to maintain a target film property. The method can be used to provide feedback to a plurality of deposition chambers or to control a film property other than film thickness.

Claims

1. A method of film deposition in a run-to-run chemical vapor deposition (CVD) process, comprising:

a) providing a model for CVD deposition of a film, wherein the model is responsive to a tool state of the CVD process and identifies one or more film properties of the film and at least one deposition model variable that correlates with the one or more film properties;

b) depositing a film onto a first substrate using a first deposition recipe comprising at least one deposition recipe parameter that corresponds to the at least one deposition variable;

c) measuring a film property of at least one of said one or more film properties for the deposited film of step (b);

d) calculating an updated deposition model based upon the measured film property of step (c) and the model of step (a),

wherein said updated model is calculated after each run of the run-to-run process; and

e) calculating an updated deposition recipe for use in a film deposition onto a second substrate based upon the updated model of step (d) to maintain a target film property.

2. The method of claim 1, wherein the model of step (a) defines a plurality of models for a plurality of regions on a wafer and identifies a film property for two or more of said plurality of regions of the wafer and at least one deposition model variable that correlates with the film property.

3. The method of claim 2, wherein the film property comprises film thickness and the step of measuring the film property further comprises determining a film thickness profile.

4. The method of claim 2, wherein calculating an updated model in step (d) comprises updating the models for one or more of the plurality of regions of the wafer.

5. The method of claim 4, wherein calculating an updated recipe in step (e) comprises updating the recipe for one or more of the plurality of regions of the wafer.

6. The method of claim 2, wherein the plurality of regions in the model of step (a) comprises annular regions extending outward from a center point on the wafer.

7. The method of claim 1, wherein the first deposition recipe is based on the model of step (a).

8. The method of claim 1, wherein the first deposition recipe is determined empirically.

9. The method of claim 1, wherein the film property of step (c) is an average film property.

10. The method of claim 1, wherein the model defines deposition of a plurality of films onto a plurality of wafers in a plurality of deposition chambers.

11. The method of claim 10, wherein the model provides for independent control of at least one deposition parameter for at least two of said plurality of deposition chambers.

12. The method of claim 11, wherein the independent deposition parameter is selected from the group consisting of showerhead spacing and wafer temperature.

13. The method of claim 10, wherein the model provides for common control of at least one deposition parameter for at least two of said plurality of deposition chambers.

14. The method of claim 13, wherein the common deposition parameter is selected from the group consisting of chamber pressure, reactive gas flow rate, carrier gas flow rate, dopant gas flow rate, and deposition time.

15. The method of claim 10, wherein the deposition recipe of step (b) in each chamber is the same.

16. The method of claim 10, wherein the deposition recipe of step (b) in each chamber is different.

17. The method of claim 10, wherein the calculating step of step (e) comprises calculating updated deposition recipes for at least two of said plurality of deposition chambers.

18. The method of claim 1, wherein the model provides for the effect of tool idle time of the CVD deposition process.

19. The method of claim 18, wherein the model defines a first deposition time when the idle time is more than a predetermined period and a second deposition time when the idle time is less than the predetermined period.

20. The method of claim 1, wherein the step of providing a model comprises:

(f) depositing a film on at least one wafer in a deposition step using a deposition recipe comprising at least one deposition recipe parameter and at least one tool state parameter that corresponds to a deposition model variable;

(g) measuring a film property for each of the at least one wafers after the deposition of step (f);

(h) recording the deposition parameter and measured film property for each of the at least one wafers on a recordable medium; and

(i) fitting the data to a linear or non-linear curve that establishes a relationship between the film property of a region of the film and the deposition model variable.

21. The method of claim 20, wherein the model constrains the deposition parameter to within predetermined maximum and minimum values.

22. The method of claim 1 or 20, wherein the at least one deposition parameters includes one or more of the parameters selected from the group consisting of deposition time, substrate temperature, ozone flow rate, reactive gas flow rate, carrier gas flow rate, dopant gas flow rate, chamber pressure and shower head spacing from the wafer.

23. The method of claim 22, wherein the at least one deposition parameter comprises deposition time.

24. The method of claim 1 or 20, wherein the one or more film properties includes one or more film properties selected from the group consisting of film thickness, film thickness uniformity, stress, wet-etch rate ratio (WERR), dopant concentration, and extinction coefficient, and refractive index (RI).

25. The method of claim 24, wherein the one or more film properties comprises film thickness.

26. The method of claim 25, wherein the film thickness for a region j of a wafer in chamber i in the model of step (a) is determined according to the equation:

Film_thickness_ij=g(x₁, x₂, . . . , x_n)_ij·

time_i

where Film_thickness_i is the film thickness of region i of the wafer in chamber i;

X₁, x₂, . . . , x_n are recipe parameters or tool state parameters which effect the deposition rate within this region;

g( ) is a function, either linear or nonlinear, which describes the dependency of these parameters upon the deposition rate within region j of chamber i; and

time_i is the deposition time in chamber i.

27. The method of claim 1, wherein updated deposition recipe is attained by solving the equation:

28. A method of determining a model for film deposition in a chemical vapor deposition process, comprising:

(a) depositing a film on at least one wafer in a chemical vapor deposition process using a deposition recipe having at least one deposition recipe parameter that and at least one tool parameter corresponds to a deposition model variable;

(b) identifying a plurality of substantially annular regions of the at least one wafer and measuring a film property of at least two of said plurality of regions for each of the at least one wafers after the deposition of step (a);

(c) recording the deposition parameter and the measured film property for at least two of the plurality of regions for each of the at least one wafers on a recordable medium; and

(d) fitting the data to establish a relationship between the film property of a substantially annular region of the wafer and the deposition model variable.

29. The method of claim 28, wherein the film property of interest is selected from the group consisting of film thickness, stress, refractive index, dopant concentration and extinction coefficient.

30. The method of claim 28, wherein the at least one deposition parameter comprises one or more parameters selected from the group consisting of deposition time, wafer temperature, ozone flow rate, oxygen flow rate, reactive gas flow rate, carrier gas flow rate, dopant gas flow rate, chamber pressure and shower head spacing from the wafer.

31. The method of claim 28, wherein the model constrains a deposition parameter in a deposition recipe to be within predetermined maximum and minimum values.