Polishing method and polishing apparatus

• US 20070049166A1
• Filed: 08/23/2006
• Published: 03/01/2007
• Est. Priority Date: 08/26/2005
• Status: Active Grant

• Current Assignee: Ebara Corporation
• Original Assignee: Ebara Corporation
• Inventors: Yamaguchi, Kuniaki, Torikoshi, Tsuneo
• Granted Patent: US 7,989,348 B2
• Time in Patent Office: Days
• US Class Current: 451/5
• CPC Class Codes: B24B 37/345 Feeding, loading or unloading work specially adapted to lapping
• CPC Class Codes: B24B 49/00 Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation B24B33/06, B24B37/005 take precedence; if applicable to other machine tools, B23Q15/00 - B23Q17/00 take precedence

Abstract

A polishing method make it possible to carry out a multi-step polishing process with improved polishing conditions (polishing recipe) while omitting measurement of the surface conditions of a substrate, as carried out between polishing steps, as much as possible, thereby increasing the throughput. The polishing method for polishing workpieces by repeating the sequential operations of taking a workpiece out of a cassette in which a plurality of workpieces are stored, carrying out multi-step polishing of a surface of the workpiece and returning the workpiece to the cassette, includes carrying out one of the following two polishing processes for the workpiece taken out of the cassette: a first polishing process comprising carrying out the multi-step polishing under preset conditions and measurement of the surface of the workpiece before and after each polishing step; and a second polishing process comprising carrying out a predetermined step of the multi-step polishing under polishing conditions which have been modified based on the results of the measurement.

Claims

1. A polishing method for polishing workpieces by repeating the sequential operations of taking a workpiece out of a cassette in which a plurality of workpieces are stored, carrying out multi-step polishing of a surface of the workpiece and returning the workpiece to the cassette, comprising carrying out one of the following two polishing processes for the workpiece taken out of the cassette:

a first polishing process comprising carrying out the multi-step polishing under preset conditions and measurement of the surface of the workpiece before and after each polishing step; and

a second polishing process comprising carrying out a predetermined step of the multi-step polishing under polishing conditions which have been modified based on the results of the measurement.

2. The polishing method according to claim 1, wherein the surface conditions of the workpiece before or after the second polishing process are determined to modify the polishing conditions for the predetermined step of the second polishing process.

3. The polishing method according to claim 1, wherein the first polishing process is carried out on the first workpiece first taken out of the cassette, and the second polishing process is carried out on the second or later workpiece later taken out of the cassette.

4. The polishing method according to claim 1, wherein determination as to which one of the first polishing process and the second polishing process is to be carried out on a workpiece is made based on information on additional polishing for the workpieces which have been polished by the second polishing process.

5. The polishing method according to claim 4, wherein the information on additional polishing is at least one of the number of workpieces which have undergone additional polishing, the rate of additional polishing, the level difference between the highest portion and the lowest portion in irregularities on a polished surface, the average or deviation of the polishing amounts of polished workpieces, and the upper or lower limit of polishing amount.

6. The polishing method according to claim 1, wherein the multi-step polishing in the first polishing process and that in the second polishing process are carried out by pressing the surface of the workpiece against a polishing pad having a polishing surface while moving the workpiece and the polishing pad relative to each other.

7. The polishing method according to claim 6, wherein the polishing conditions for the first polishing process and the second polishing process are set based on the degree of wear of the polishing pad and/or the temperature of the polishing surface of the polishing pad.

8. The polishing method according to claim 1, wherein the polishing conditions for the first polishing process and the second polishing process are set based on the degree of wear of a consumable member used in the multi-step polishing of the first polishing process and that of the second polishing process.

9. The polishing method according to claim 1, wherein the surface conditions of the workpiece after polishing are calculated in advance of the polishing, and polishing conditions are set based on the predicted post-polishing surface conditions determined by the calculation.

10. A polishing method for polishing workpieces by repeating the sequential operations of taking a workpiece out of a cassette in which a plurality of workpieces are stored, carrying out multi-step polishing of a surface of the workpiece and returning the workpiece to the cassette, comprising carrying out one of the following two polishing processes for the workpiece taken out of the cassette:

a first polishing process comprising carrying out the multi-step polishing under preset conditions and measurement of the surface of the workpiece before and after each polishing step; and

a second polishing process comprising carrying out at least one step of the multi steps under polishing conditions which have been modified based on the results of the measurement.

11. The polishing method according to claim 10, wherein the surface conditions of the workpiece before or after the second polishing process are determined to modify the polishing conditions for the at least one step of the multi steps of the second polishing process.

12. The polishing method according to claim 10, wherein the first polishing process is carried out on the first workpiece first taken out of the cassette, and the second polishing process is carried out on the second or later workpiece later taken out of the cassette.

13. The polishing method according to claim 10, wherein determination as to which one of the first polishing process and the second polishing process is to be carried out on a workpiece is made based on information on additional polishing for the workpieces which have been polished by the second polishing process.

14. The polishing method according to claim 13, wherein the information on additional polishing is at least one of the number of workpieces which have undergone additional polishing, the rate of additional polishing, the level difference between the highest portion and the lowest portion in irregularities on a polished surface, the average or deviation of the polishing amounts of polished workpieces, and the upper or lower limit of polishing amount.

15. The polishing method according to claim 10, wherein the multi-step polishing in the first polishing process and that in the second polishing process are carried out by pressing the surface of the workpiece against a polishing pad having a polishing surface while moving the workpiece and the polishing pad relative to each other.

16. The polishing method according to claim 15, wherein the polishing conditions for the first polishing process and the second polishing process are set based on the degree of wear of the polishing pad and/or the temperature of the polishing surface of the polishing pad.

17. The polishing method according to claim 10, wherein the polishing conditions for the first polishing process and the second polishing process are set based on the degree of wear of a consumable member used in the multi-step polishing of the first polishing process and that of the second polishing process.

18. The polishing method according to claim 10, wherein the surface conditions of the workpiece after polishing are calculated in advance of the polishing, and polishing conditions are set based on the predicted post-polishing surface conditions determined by the calculation.

19. A polishing method for polishing a surface of a workpiece having a laminate of a plurality of various films, comprising:

preparing a polishing liquid having a selectivity for the various films;

calculating a synthetic film thickness value by multiplying a thickness of each film of the various films by a coefficient corresponding to the selectivity, and setting polishing conditions based on the synthetic film thickness value; and

polishing the surface of the workpiece by pressing the surface against a polishing surface while supplying the polishing liquid to the polishing surface.

20. The polishing method according to claim 19, wherein the surface conditions of the workpiece after polishing are calculated in advance of the polishing, and polishing conditions are set based on the predicted post-polishing surface conditions determined by the calculation.

21. A polishing apparatus comprising:

a polishing section for carrying out multi-step polishing of a surface of a workpiece;

a measurement section for measuring the surface of the workpiece; and

a control section for setting polishing conditions based on the results of measurement with the measurement section of the surface of the workpiece;

wherein the control section modifies polishing conditions for a predetermined step of polishing of the surface of a Nth workpiece based on the results of measurement of the surface of a workpiece before and after the predetermined step of polishing carried out under preset conditions.

22. The polishing apparatus according to claim 21, wherein the control section includes a recording section for storing the results of measurement with the measurement section of the surface of the workpiece.

23. The polishing apparatus according to claim 22, wherein the control section refers to a recording medium which is provided in a cassette with a plurality of workpieces stored therein and in which information of the workpieces is recorded, and checks whether the information on the surface of the workpiece is stored in the recording section.

24. A polishing apparatus comprising:

a polishing section for carrying out multi-step polishing of a surface of a workpiece;

a measurement section for measuring the surface of the workpiece; and

a control section for setting polishing conditions based on the results of measurement with the measurement section of the surface of the workpiece;

wherein the control section modifies polishing conditions for at least one step of polishing of the surface of a Nth workpiece based on the results of measurement of a surface of a workpiece before and after each step of polishing carried out under preset conditions.

25. The polishing apparatus according to claim 24, wherein the control section includes a recording section for storing the results of measurement with the measurement section of the surface of the workpiece.

26. The polishing apparatus according to claim 25, wherein the control section refers to a recording medium which is provided in a cassette with a plurality of workpieces stored therein and in which information of the workpieces is recorded, and checks whether the information on the surface of the workpiece is stored in the recording section.

27. A polishing apparatus comprising:

a top ring for holding a workpiece, having in a surface a laminate of various types of films, and pressing the workpiece against a polishing surface;

a rotational drive section for rotating the top ring and the workpiece relative to each other;

a first measurement section for measuring a load of the rotational drive section;

a second measurement section for optically measuring a surface of the workpiece after polishing; and

a control section for setting polishing conditions for polishing of a surface of a Nth substrate based on the results of measurement with the first measurement section and the results of measurement with the second measurement section.

28. The polishing apparatus according to claim 27, wherein the second measurement section measures the entire surface of the workpiece;

the top ring includes an adjustment means for dividing the workpiece surface, pressing on the polishing surface, into a plurality of areas, and adjusting a pressure of each area on the polishing surface; and

the control section adjusts a pressure applied by the top ring on each of the areas of the workpiece surface based on the results of measurement with the second measurement section.

29. The polishing apparatus according to claim 28, wherein the control section adjusts the polishing conditions, in terms of the polishing rate, based on the results of measurement with the second measurement section carried out at a plurality of points on the surface of the workpiece.

30. The polishing apparatus according to claim 29, wherein the control section adjusts the pressure of the top ring on each of the areas of the workpiece surface based on the results of measurement with the second measurement section carried out at a plurality points, not overlapping with the points used for the adjustment of the polishing rate, on the surface of the workpiece.

31. A polishing apparatus comprising:

a polishing section for polishing a workpiece having in a surface a laminate of a plurality of various films;

a polishing liquid supply nozzle for supplying a polishing liquid having a selectivity for the various films; and

a control section for setting polishing conditions in the polishing section;

wherein the control section calculates a synthetic film thickness value by multiplying a thickness of each film of the various films by a coefficient corresponding to the selectivity, and sets polishing conditions for polishing the surface of the workpiece based on the synthetic film thickness value.

32. A program for controlling a polishing apparatus, which polishes workpieces by repeating the sequential operations of taking a workpiece out of a cassette in which a plurality of workpieces are stored, carrying out multi-step polishing of a surface of the workpiece and returning the workpiece to the cassette, to perform an operation of:

modifying polishing conditions for a predetermined step of polishing of a surface of a Nth workpiece based on the results of measurement of a surface of a workpiece taken out of the cassette, carried out before and after the predetermined step of polishing carried out under preset conditions.

33. A program for controlling a polishing apparatus, which polishes workpieces by repeating the sequential operations of taking a workpiece out of a cassette in which a plurality of workpieces are stored, carrying out multi-step polishing of a surface of the workpiece and returning the workpiece to the cassette, to perform an operation of:

modifying polishing conditions for at least one step of polishing of a surface of a Nth workpiece based on the results of measurement of a surface of a workpiece taken out of the cassette, carried out before and after each step of polishing carried out under preset conditions.

34. A program for controlling a polishing apparatus, which polishes workpieces by repeating the sequential operations of taking a workpiece out of a cassette in which a plurality of workpieces are stored, carrying out multi-step polishing of a surface of the workpiece and returning the workpiece to the cassette, to perform operations of:

performing a first polishing process comprising carrying out the multi-step polishing under preset conditions and measurement of the surface of the workpiece before and after each polishing step, and a second polishing process comprising carrying out the second or later step of the multi-step polishing under polishing conditions which have been modified based on the results of the measurement; and

changing polishing conditions from those of the second polishing process to those of the first polishing process.