Optimization algorithm to optimize within substrate uniformities

• US 7,289,865 B2
• Filed: 07/14/2004
• Issued: 10/30/2007
• Est. Priority Date: 07/14/2004
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM America Incorporated (ASM International NV)
• Inventors: Bauer, Matthias
• Primary Examiner(s): Jarrett; Ryan A
• Application Number:
  US10/892,013
• Publication Number:
  US 20060031788A1
• Time in Patent Office: 1,203 Days
• Field of Search: 700/109, 700/110, 700/121
• US Class Current: 700/121
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps
• CPC Class Codes: H01L 22/34 Circuits for electrically characterising or monitoring manufacturing processes, e. g. whole test die, wafers filled with test structures, on-board-devices incorporated on each die, process control monitors or pad structures thereof, devices in scribe line switching, multiplexing, gating devices G01R19/25; process control with lithography, e.g. dose control, G03F7/20; structures for alignment control by optical means G03F7/70633
• 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

A method to optimize semiconductor processing equipment (hardware settings and process conditions) to minimize non-uniformities within a wafer based on linescan measurements and a calculation of or prediction for a polar map. Measurements of a metrology value are taken at a number of points along a linescan (or two orthogonal linescans) on the wafer surface for a number of wafer processed in a set of experiments in which one equipment setting or process parameter is adjusted per experiment. The raw data are then normalized and weighted in accordance with the radial distance from the center of the wafer. Standard deviations of different metrology values within the wafer are then calculated. The setting can then be further adjusted to predict and to minimize the standard deviations, and therefore non-uniformity of the metrology values within the wafer, using the method without processing any additional test wafers.

Claims

1. A method of optimizing semiconductor manufacturing equipment to minimize non-uniformity of a wafer processed in a semiconductor processing chamber, comprising:

obtaining a plurality of measurements of a wafer parameter of a first wafer processed in the chamber comprising taking data from a linescan;

weighting the plurality of measurements of the first wafer according to a radial distance from a center of the first wafer;

adjusting at least one setting of the chamber;

processing one test wafer for each setting adjusted;

obtaining a plurality of measurements of the wafer parameter of each test wafer processed in the chamber for each setting adjusted, wherein the plurality of measurements comprise data from a linescan;

creating a model relating each setting adjusted to a measure of non-uniformity of the wafer parameter using the plurality of measurements and weighted measurements;

using the model to minimize the measure of non-uniformity to determine an optimal setting for the at least one setting; and

adjusting the at least one setting of the chamber to the optimal setting.

2. The method of claim 1, further comprising:

weighting the plurality of measurements of each test wafer according to a radial distance from a center of each test wafer; and

calculating normalized weighted measurements by normalizing the weighted measurements before creating the model and inputting the normalized weighted measurements into a template created with the plurality of measurements and the weighted measurements.

3. The method of claim 1, wherein the measure of non-uniformity of the wafer parameter is a standard deviation of the wafer parameter.

4. The method of claim 1, wherein the method is performed using data from only the first wafer and one test wafer for each setting.

5. The method of claim 1, wherein the plurality of measurements of the first wafer are weighted by weighting radially outer portions of the first wafer more than the center of the first wafer.

6. The method of claim 1, further comprising weighting the plurality of measurements of the test wafer according to a radial distance from a center of the test wafer, wherein weighting occurs before creating the model.

7. The method of claim 2, further comprising comparing the normalized weighted measurements of the first wafer with the normalized weighted measurements of the test wafer.

8. The method of claim 1, wherein obtaining a plurality of measurements comprises calculating a polar map of the wafer parameter from the linescan data.

9. The method of claim 8, wherein the measure of non-uniformity is a standard deviation of the polar map of the wafer parameter.

10. The method of claim 1, wherein the parameter is thickness of a layer deposited during processing.

11. The method of claim 1, wherein processing is etching and the parameter is a thickness of a layer etched during processing.

12. The method of claim 1, wherein the parameter is resistivity of a layer deposited during processing.

13. The method of claim 1, wherein the parameter is sheet resistivity of a layer deposited during processing.

14. The method of claim 1, further comprising processing a process wafer in the chamber at the optimal setting to minimize non-uniformity in the process wafer.

15. The method of claim 1, wherein the model is created after processing only one test wafer for each setting adjusted.

16. A method of adjusting a semiconductor integrated circuit processing chamber for processing a substrate, comprising:

obtaining measurements of a parameter of a first substrate processed in the chamber at a plurality of points on a linescan of the first substrate;

adjusting a setting of the chamber;

obtaining measurements of the parameter of a second substrate processed in the chamber at a plurality of points on a linescan of the second substrate after adjusting the setting;

calculating a measure of non-uniformity of the parameter by weighting the measurements in accordance with a corresponding radial distance from a center of the first and second substrates;

creating a model relating the setting adjusted to the measure of non-uniformity to minimize the measure of non-uniformity; and

adjusting the setting to a predicted setting based on the minimized measure of non-uniformity.

17. The method of claim 16, wherein the measure of non-uniformity is minimized using iterative calculation.

18. The method of claim 17, wherein the measure of non-uniformity is minimized without processing any additional substrates.

19. The method of claim 16, wherein the measure of non-uniformity of the parameter is a standard deviation of the parameter.

20. The method of claim 16, wherein obtaining measurements of a parameter comprises calculating a polar map of the parameter from the linescan.

21. The method of claim 16, wherein calculating the measure of non-uniformity comprises calculating a weighted mean value of the parameter by weighting measurements at points in radially outer portions of the first substrate more than measurements at points at a center of the first substrate.

22. The method of claim 16, further comprising:

adjusting additional settings and processing one additional substrate for each additional setting adjusted;

obtaining measurements of a parameter of each additional substrate processed in the chamber at a plurality of points on a linescan of each additional substrate after adjusting each additional setting;

calculating a measure of non-uniformity of the parameter of each of the additional substrates by weighting the measurements in accordance with a corresponding radial distance from a center of each additional substrate; and

creating a model relating the settings adjusted to the measures of non-uniformity of each of the parameters to minimize the measures of non-uniformity.

23. The method of claim 16, further comprising processing a process wafer in the chamber at the predicted setting after adjusting the setting to the predicted setting.

24. A method of adjusting a semiconductor integrated circuit processing chamber for processing a wafer, comprising:

processing a first wafer in the processing chamber using baseline equipment settings;

obtaining measurements of a parameter of the first wafer at a plurality of points along a linescan on the first wafer;

calculating a weighted mean value of the parameter by weighting the mean value by weighting radially outer portions of the first wafer more than a center of the first wafer;

adjusting a setting of the processing chamber by a factor;

processing a second wafer in the processing chamber after adjusting the setting;

obtaining measurements of the parameter of the second wafer at a plurality of points along a linescan on the second wafer;

calculating a weighted mean value of the parameter by weighting the mean value by weighting radially outer portions of the second wafer more than a center of the second wafer;

calculating a polar map of the wafer parameter for the first wafer using the measurements obtained;

calculating a standard deviation of the parameter within the first wafer, wherein the standard deviation is a standard deviation of the polar map;

calculating an optimal setting by minimizing the standard deviation; and

adjusting the setting to the optimal setting.

25. The method of claim 24, further comprising calculating an adjusted normalized value of the parameter for each of the plurality of points after calculating the polar map and before calculating the standard deviation.

26. The method of claim 24, wherein the optimal setting is calculated without processing any additional wafers.

27. The method of claim 24, wherein the linescan has 7-49 points.

28. The method of claim 24, wherein the parameter is thickness.

29. The method of claim 24, wherein the parameter is resistivity.

30. The method of claim 24, wherein the parameter is sheet resistivity.

31. The method of claim 24, wherein the setting is selected from the group consisting of main gas flow distribution settings, pressure, hydrogen flow, silicon precursor flow, germanium precursor flow, carbon precursor flow, dopant flow, dopant distribution, temperature offsets, and SCR power ratios.

32. The method of claim 24, wherein the standard deviation is minimized using a computer-based optimization tool.

33. The method of claim 24, further comprising the step of feeding the standard deviation into software for controlling the processing chamber to adjust the setting before adjusting the setting to the optimal setting.

34. The method of claim 24, further comprising processing a process wafer in the chamber after adjusting the setting to the optimal setting.

35. A method of optimizing semiconductor manufacturing equipment to minimize non-uniformity of a wafer processed in a semiconductor processing chamber, comprising:

obtaining a plurality of measurements of a wafer parameter of a first rotated wafer processed in the chamber, wherein the plurality of measurements are taken along a linescan;

weighting the plurality of measurements of the first rotated wafer according to a radial distance from a center of the first rotated wafer;

adjusting at least one setting of the chamber and processing one rotated test wafer for each adjusted setting;

obtaining a plurality of measurements of the wafer parameter of each rotated test wafer processed in the chamber for each adjusted setting, wherein the plurality of measurements are taken along a linescan;

creating a model relating the setting to an indicator of non-uniformity of the wafer parameter by using data from the plurality of measurements and the weighted measurements;

using the model to minimize the indicator of non-uniformity; and

adjusting the at least one setting to an optimal setting based on the minimized indicator of non-uniformity.

36. The method of claim 35, wherein the at least one setting comprises gas flow distribution.

37. The method of claim 35, wherein the at least one setting comprises temperature control.

38. The method of claim 35, further comprising processing a process wafer in the chamber at the optimal setting.

39. A method of adjusting a semiconductor integrated circuit processing chamber for processing a wafer, comprising:

obtaining measurements of a parameter of a baseline substrate processed in the chamber at a plurality of points on a linescan of the baseline substrate;

adjusting at least one setting of the chamber and processing one test wafer in the chamber for each at least one setting adjusted, wherein the at least one setting comprises a gas injector setting;

obtaining measurements of the parameter of each test wafer processed in the chamber for each at least one setting adjusted, wherein the measurements are taken along a linescan;

weighting the plurality of measurements according to a radial distance from a center;

creating a predictive model relating the at least one setting to a measure of non-uniformity of the parameter within the substrate by using the measurements and the weighted measurements to minimize the measure of non-uniformity; and

adjusting the at least one setting to a predicted setting based on the minimized measure of non-uniformity.

40. The method of claim 39, wherein the at least one setting further comprises temperature control.

41. The method of claim 39, wherein the at least one setting further comprises one or more settings selected from the group consisting of pressure, hydrogen flow, silicon precursor flow, germanium precursor flow, carbon precursor flow, dopant flow, dopant distribution, temperature offsets, and SCR power ratios.

42. The method of claim 39, further comprising processing a process wafer in the chamber at the predicted setting.