Methods and apparatuses for monitoring and controlling mechanical or chemical-mechanical planarization of microelectronic substrate assemblies

• US 20020124957A1
• Filed: 05/02/2002
• Published: 09/12/2002
• Est. Priority Date: 08/31/1999
• Status: Active Grant

• Current Assignee: Gundu M. Sabde, James J. Hofmann, Michael James Joslyn, Stephen J. Kramer
• Original Assignee: Gundu M. Sabde, James J. Hofmann, Michael James Joslyn, Stephen J. Kramer
• Inventors: Joslyn, Michael James, Kramer, Stephen J., Hofmann, James J., Sabde, Gundu M.
• Granted Patent: US 6,682,628 B2
• Time in Patent Office: Days
• US Class Current: 156/345.12
• CPC Class Codes: B24B 37/013 Devices or means for detecting lapping completion
• CPC Class Codes: B24B 37/042 operating processes therefor
• CPC Class Codes: B24B 49/16 taking regard of the load
• CPC Class Codes: H01L 21/30625 With simultaneous mechanical treatment, e.g. mechanico-chemical polishing

Abstract

Methods and apparatuses for mechanical and/or chemical-mechanical planarization of semiconductor wafers, field emission displays and other microelectronic substrate assemblies. One method of planarizing a microelectronic substrate assembly in accordance with the invention includes pressing a substrate assembly against a planarizing surface of a polishing pad at a pad/substrate interface defined by a surface area of the substrate assembly contacting the planarizing surface. The method continues by moving the substrate assembly and/or the polishing pad with respect to the other to rub at least one of the substrate assembly and the planarizing surface against the other at a relative velocity. As the substrate assembly and polishing pad rub against each other, a parameter indicative of drag force between the substrate assembly and the polishing pad is measured or sensed at periodic intervals. The measured drag force can be used to generate a plot of work versus time. The work versus time plot is then integrated to determine an estimated work exerted at the pad/substrate interface. The planarizing process is terminated when the estimated thickness is at least approximately within a range of desired substrate assembly thickness for endpointing the substrate assembly according to a predetermined relationship between work and substrate assembly thickness.

Claims

1. A method of planarizing a microelectronic substrate assembly, comprising:

pressing a substrate assembly against a planarizing surface of a polishing pad at a pad/substrate interface defined by a surface area of the substrate assembly contacting the planarizing surface;

moving the substrate assembly and/or the polishing pad with respect to the other to rub at least one of the substrate assembly and the planarizing surface against the other at a relative velocity;

determining an association between work exerted at the pad/substrate interface and a thickness of the substrate assembly;

measuring a parameter indicative of drag force between the substrate assembly and the polishing pad at periodic intervals and generating a plot of measured drag force values versus time;

integrating the product of the measured drag force values and the relative velocity over time to determine an estimated work exerted at the pad/substrate interface;

correlating the estimated work with the association between work at the pad/substrate interface and change in thickness of the substrate assembly to ascertain an estimated thickness of the substrate assembly; and

terminating removal of material from the substrate assembly when the estimated thickness is at least approximately within a range of desired substrate assembly thickness for endpointing the substrate assembly.

2. The method of claim 1, further comprising:

providing a planarizing machine having a table to support the a polishing pad, a carrier head to hold the substrate assembly, and a force detector positioned at a load site on one of the table or the carrier head to measure lateral forces between the substrate and the pad; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

3. The method of claim 1 further comprising:

providing a planarizing machine having a table to support the polishing pad, a carrier head and a force detector, the carrier head including a chuck having a bottom section including a substrate holder facing the pad, a top section including a cavity having a sidewall, a pivoting joint in the cavity, and a shaft having an end section received in the cavity and attached to the pivoting joint, and the force detector being attached to one side-wall of the cavity or the end section of the shaft; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

4. The method of claim 1, further comprising:

providing a planarizing machine having a table to support the polishing pad, a carrier head and a force detector, the carrier head including a chuck having a bottom section including a substrate holder facing the pad, a top section including a cavity having a sidewall, a pivoting joint in the cavity, and a shaft having an end section received in the cavity and attached to the pivoting joint, and the force detector comprising a pressure sensitive ring attached to a side-wall of the cavity; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

5. The method of claim 1, further comprising

providing a planarizing machine having a table to support the polishing pad, a carrier head and a force detector, the carrier head including a chuck having a bottom section including a substrate holder facing the pad, a top section including a cavity having a sidewall, a pivoting joint in the cavity, and a shaft having an end section received in the cavity and attached to the pivoting joint, and the force detector comprising a pressure sensitive ring attached to the end section of the shaft;

and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

6. The method of claim 1, further comprising:

providing a planarizing machine having a table including a base and a primary plate movably attached to the base to move in a lateral motion corresponding to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector contacting a stop surface of the base extending transverse to the planarizing surface and a contact surface of the primary plate adjacent to the stop surface; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

7. The method of claim 1, further comprising:

providing a planarizing machine having a table including a base and a primary plate assembly moveable with respect to the base in a lateral motion corresponding to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector coupled to the primary plate assembly to sense lateral displacement between the base and the primary plate corresponding to the lateral forces between the base and the primary plate, the polishing pad being removably attached to the primary plate; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

8. The method of claim 1, further comprising:

providing a planarizing machine having a table including a base and a primary plate attached to the base by a post, a carrier head to hold the substrate assembly, and a force detector coupled to the post to sense displacement between the base and the primary plate corresponding to the lateral forces between the base and the primary plate, the polishing pad being removably attached to the primary plate; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

9. The method of claim 1, further comprising:

providing a planarizing machine having a table including a base and a primary plate attached to the base by a plurality of flexible posts that deflect to provide at least limited lateral displacement between the primary plate and the base in correspondence to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector coupled to at least one of the posts to detect deflection of the posts corresponding to the lateral displacement between the primary plate and the base; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

10. The method of claim 1, further comprising

providing a planarizing machine having a table including a base and a primary plate attached to the base by a plurality of flexible posts that deflect to allow lateral displacement between the primary plate and the base in correspondence to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector between a stop surface of the base extending transverse to the planarizing surface and a contact surface of the primary plate adjacent to the stop surface to detect the lateral drag forces;

and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

11. A method of planarizing a microelectronic substrate assembly, comprising:

removing material from a substrate assembly using a polishing pad by rubbing at least one of the substrate assembly and the polishing pad against the other at a relative velocity, the substrate assembly contacting a planarizing surface of the polishing pad at a pad/substrate interface;

estimating total work exerted at the pad/substrate interface to rub the planarizing surface against the substrate assembly; and

terminating removal of material from the substrate assembly when the estimated work corresponds to a desired change in thickness of the substrate assembly according to a predetermined relationship between work and change in substrate assembly thickness.

12. The method of claim 11, further comprising:

providing a planarizing machine having a table to support the a polishing pad, a carrier head to hold the substrate assembly, and a force detector positioned at a load site on one of the table or the carrier head to measure lateral forces between the substrate and the pad; and

estimating work at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by an estimated work versus time plot.

13. The method of claim 11, further comprising providing a planarizing machine having a table to support the polishing pad, a carrier head to hold the substrate assembly, and a force detector positioned at a load site on one of the table or the carrier head to measure lateral forces between the substrate and the pad, and wherein estimating work performed at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by an estimated work versus time plot by integrating the following equation where F_D is the measured lateral force, V_r is the relative velocity between the pad and the substrate assembly and dt is the time differential:

W_T=∫

_t0^tF_D·

V_rdt.

14. The method of claim 11, further comprising:

providing a planarizing machine having a table to support the polishing pad, a carrier head and a force detector, the carrier head including a chuck having a bottom section including a substrate holder facing the pad, a top section including a cavity having a sidewall, a pivoting joint in the cavity, and a shaft having an end section received in the cavity and attached to the pivoting joint, and the force detector being attached to one side-wall of the cavity or the end section of the shaft; and

wherein estimating work performed at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by a lateral force versus time plot.

15. The method of claim 11, further comprising:

providing a planarizing machine having a table to support the polishing pad, a carrier head and a force detector, the carrier head including a chuck having a bottom section including a substrate holder facing the pad, a top section including a cavity having a sidewall, a pivoting joint in the cavity, and a shaft having an end section received in the cavity and attached to the pivoting joint, and the force detector comprising a pressure sensitive ring attached to a side-wall of the cavity; and

estimating work performed at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by a lateral force versus time plot.

16. The method of claim 11, further comprising:

providing a planarizing machine having a table to support the polishing pad, a carrier head and a force detector, the carrier head including a chuck having a bottom section including a substrate holder facing the pad, a top section including a cavity having a sidewall, a pivoting joint in the cavity, and a shaft having an end section received in the cavity and attached to the pivoting joint, and the force detector comprising a pressure sensitive ring attached to the end section of the shaft; and

estimating work performed at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by a lateral force versus time plot.

17. The method of claim 11, further comprising:

providing a planarizing machine having a table including a base and a primary plate movably attached to the base to move in a lateral motion corresponding to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector contacting a stop surface of the base extending transverse to the planarizing surface and a contact surface of the primary plate adjacent to the stop surface; and

estimating work performed at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by a lateral force versus time plot.

18. The method of claim 11 wherein:

providing a planarizing machine having a table including a base and a primary plate assembly moveable with respect to the base in a lateral motion corresponding to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector coupled to the primary plate assembly to sense lateral displacement between the base and the primary plate corresponding to the lateral forces between the base and the primary plate, the polishing pad being removably attached to the primary plate; and

estimating work performed at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by a lateral force versus time plot.

19. The method of claim 11, further comprising:

providing a planarizing machine having a table including a base and a primary plate attached to the base by a post, a carrier head to hold the substrate assembly, and a force detector coupled to the post to sense displacement between the base and the primary plate corresponding to the lateral forces between the base and the primary plate, the polishing pad being removably attached to the primary plate; and

estimating work performed at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by a lateral force versus time plot.

20. The method of claim 11, further comprising:

providing a planarizing machine having a table including a base and a primary plate attached to the base by a plurality of flexible posts that deflect to provide at least limited lateral displacement between the primary plate and the base in correspondence to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector coupled to at least one of the posts to detect deflection of the posts corresponding to the lateral displacement between the primary plate and the base; and

estimating work performed at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by a lateral force versus time plot.

21. The method of claim 11, further comprising:

providing a planarizing machine having a table including a base and a primary plate attached to the base by a plurality of flexible posts that deflect to allow lateral displacement between the primary plate and the base in correspondence to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector between a stop surface of the base extending transverse to the planarizing surface and a contact surface of the primary plate adjacent to the stop surface to detect the lateral drag forces; and

estimating work performed at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by a lateral force versus time plot.

22. The method of claim 11, further comprising determining the predetermined relationship between work and substrate thickness by measuring drag force between the substrate assembly and the polishing pad, measuring an actual thickness of the substrate assembly corresponding to each measured drag force to create work/thickness data points, and performing a mathematical regression of the data points to generate a straight-line association between work at the pad/substrate interface and thickness of the substrate assembly.

23. The method of claim 11 wherein estimating work at the pad/substrate interface further comprises:

measuring a parameter indicative of drag force between the substrate assembly and the polishing pad at periodic intervals to determine measured drag forces at the periodic intervals; and

determining an area under a line defined by a measured drag force versus time plot.

24. The method of claim 11 wherein estimating work at the pad/substrate interface comprises:

isolating a parameter indicative of drag force between the substrate assembly and the polishing pad that is not influenced by energy losses in components that drive either the polishing pad or the substrate assembly;

measuring the isolated parameter periodically to determine measured drag forces at periodic intervals; and

determining an area under a line defined by a measured drag force versus time plot.

25. The method of claim 11 wherein terminating removal of material from the substrate assembly further comprises:

determining the predetermined relationship between work and substrate thickness by measuring drag force between the substrate assembly and the polishing pad, measuring an actual thickness of the substrate assembly corresponding to each measured drag force to create work/thickness data points, and performing a mathematical regression of the data points to generate a straight-line association between work at the pad/substrate interface and thickness of the substrate assembly;

correlating the estimated work with the straight line relationship to ascertain an estimated thickness of the substrate assembly; and

disengaging the substrate assembly from the polishing pad when the estimated thickness of the substrate assembly is within a desired endpoint range.

27. The method of claim 26, further comprising:

providing a planarizing machine having a table to support the a polishing pad, a carrier head to hold the substrate assembly, and a force detector positioned at a load site on one of the table or the carrier head to measure lateral forces between the substrate and the pad; and

estimating work at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by a lateral force versus time plot.

28. The method of claim 26, further comprising providing a planarizing machine having a table to support the polishing pad, a carrier head to hold the substrate assembly, and a force detector positioned at a load site on one of the table or the carrier head to measure lateral forces between the substrate and the pad, and wherein estimating work performed at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by an estimated work versus time plot by integrating the following equation where F_D is the measured lateral force, V_r is the relative velocity between the pad and the substrate assembly, and dt is the time differential:

W_T=∫

_t0^tF_D·

V_rdt.

29. The method of claim 26, further comprising:

providing a planarizing machine having a table including a base and a primary plate assembly moveable with respect to the base in a lateral motion corresponding to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector coupled to the primary plate assembly to sense lateral displacement between the base and the primary plate corresponding to the lateral forces between the base and the primary plate, the polishing pad being removably attached to the primary plate; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

30. The method of claim 26, further comprising:

providing a planarizing machine having a table including a base and a primary plate attached to the base by a post, a carrier head to hold the substrate assembly, and a force detector coupled to the post to sense displacement between the base and the primary plate corresponding to the lateral forces between the base and the primary plate, the polishing pad being removably attached to the primary plate; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

31. The method of claim 26, further comprising:

providing a planarizing machine having a table including a base and a primary plate attached to the base by a plurality of flexible posts that deflect to provide at least limited lateral displacement between the primary plate and the base in correspondence to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector coupled to at least one of the posts to detect deflection of the posts corresponding to the lateral displacement between the primary plate and the base; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

26. A method of planarizing a microelectronic substrate assembly, comprising:

removing material from a substrate assembly using a polishing pad by rubbing at least one of the substrate assembly and the polishing pad against the other at a relative velocity, the substrate assembly contacting a planarizing surface of the polishing pad at a pad/substrate interface;

determining a linear relationship between work exerted at the pad/substrate interface and a change in thickness of the substrate assembly;

estimating work at the pad/substrate interface; and

terminating removal of material from the substrate assembly when the estimated work at the pad/substrate interface corresponds to a change in thickness according the linear relationship that is at least approximately within a range of desired change in thickness for endpointing the substrate assembly.

32. A method of planarizing a microelectronic substrate assembly, comprising:

removing material from a substrate assembly using a polishing pad by rubbing at least one of the substrate assembly and the polishing pad against the other at a relative velocity, the substrate assembly contacting a planarizing surface of the polishing pad at a pad/substrate interface;

determining a linear relationship between work exerted at the pad/substrate interface and a change in thickness of the substrate assembly;

estimating work exerted at the pad/substrate interface by measuring drag force between the substrate assembly and the pad at periodic intervals and integrating the product of the measured drag force and the relative velocity over time; and

terminating removal of material from the substrate assembly when the estimated work exerted at the pad/substrate interface corresponds to a change in thickness according the linear relationship that is at least approximately within a range of desired change in thickness for endpointing the substrate assembly.

33. The method of claim 32, further comprising:

providing a planarizing machine having a table to support the a polishing pad, a carrier head to hold the substrate assembly, and a force detector positioned at a load site on one of the table or the carrier head to measure lateral forces between the substrate and the pad; and

estimating work performed at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by a lateral force versus time plot.

34. The method of claim 32, further comprising providing a planarizing machine having a table to support the polishing pad, a carrier head to hold the substrate assembly, and a force detector positioned at a load site on one of the table or the carrier head to measure lateral forces between the substrate and the pad, and wherein estimating work performed at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by an estimated work versus time plot by integrating the following equation where F_D is the measured lateral force, V_r is the relative velocity between the pad and the substrate assembly, and dt is the time differential:

W_T=∫

_t0^tF_D·

V_rdt.

35. The method of claim 32, further comprising:

providing a planarizing machine having a table including a base and a primary plate assembly moveable with respect to the base in a lateral motion corresponding to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector coupled to the primary plate assembly to sense lateral displacement between the base and the primary plate corresponding to the lateral forces between the base and the primary plate, the polishing pad being removably attached to the primary plate; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

36. The method of claim 32, further comprising:

providing a planarizing machine having a table including a base and a primary plate attached to the base by a post, a carrier head to hold the substrate assembly, and a force detector coupled to the post to sense displacement between the base and the primary plate corresponding to the lateral forces between the base and the primary plate, the polishing pad being removably attached to the primary plate; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

37. The method of claim 32, further comprising:

providing a planarizing machine having a table including a base and a primary plate attached to the base by a plurality of flexible posts that deflect to provide at least limited lateral displacement between the primary plate and the base in correspondence to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector coupled to at least one of the posts to detect deflection of the posts corresponding to the lateral displacement between the primary plate and the base; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

39. The method of claim 38, further comprising:

providing a planarizing machine having a table to support the a polishing pad, a carrier head to hold the substrate assembly, and a force detector positioned at a load site on one of the table or the carrier head to measure lateral forces between the substrate and the pad; and

estimating work at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by an estimated work versus time plot.

40. The method of claim 38, further comprising providing a planarizing machine having a table to support the polishing pad, a carrier head to hold the substrate assembly, and a force detector positioned at a load site on one of the table or the carrier head to measure lateral forces between the substrate and the pad, and wherein estimating work performed at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by an estimated work versus time plot by integrating the following equation where F_D is the measured lateral force, V_r is the relative velocity between the pad and the substrate assembly, and dt is the time differential:

W_T=∫

_t0^tF_D·

V_rdt.

41. The method of claim 38, further comprising:

providing a planarizing machine having a table to support the polishing pad, a carrier head and a force detector, the carrier head including a chuck having a bottom section including a substrate holder facing the pad, a top section including a cavity having a sidewall, a pivoting joint in the cavity, and a shaft having an end section received in the cavity and attached to the pivoting joint, and the force detector being attached to one side-wall of the cavity or the end section of the shaft; and

wherein estimating work performed at the pad/substrate interface comprises measuring the lateral forces between the substrate assembly and the pad with the force detector and determining an area under a line defined by a lateral force versus time plot.

42. The method of claim 38, further comprising:

providing a planarizing machine having a table to support the polishing pad, a carrier head and a force detector, the carrier head including a chuck having a bottom section including a substrate holder facing the pad, a top section including a cavity having a sidewall, a pivoting joint in the cavity, and a shaft having an end section received in the cavity and attached to the pivoting joint, and the force detector comprising a pressure sensitive ring attached to a side-wall of the cavity; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

43. The method of claim 38, further comprising:

providing a planarizing machine having a table to support the polishing pad, a carrier head and a force detector, the carrier head including a chuck having a bottom section including a substrate holder facing the pad, a top section including a cavity having a sidewall, a pivoting joint in the cavity, and a shaft having an end section received in the cavity and attached to the pivoting joint, and the force detector comprising a pressure sensitive ring attached to the end section of the shaft; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

44. The method of claim 38, further comprising:

providing a planarizing machine having a table including a base and a primary plate movably attached to the base to move in a lateral motion corresponding to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector contacting a stop surface of the base extending transverse to the planarizing surface and a contact surface of the primary plate adjacent to the stop surface; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

45. The method of claim 38, further comprising:

providing a planarizing machine having a table including a base and a primary plate assembly moveable with respect to the base in a lateral motion corresponding to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector coupled to the primary plate assembly to sense lateral displacement between the base and the primary plate corresponding to the lateral forces between the base and the primary plate, the polishing pad being removably attached to the primary plate; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

46. The method of claim 38, further comprising:

providing a planarizing machine having a table including a base and a primary plate attached to the base by a post, a carrier head to hold the substrate assembly, and a force detector coupled to the post to sense displacement between the base and the primary plate corresponding to the lateral forces between the base and the primary plate, the polishing pad being removably attached to the primary plate; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

47. The method of claim 38, further comprising:

providing a planarizing machine having a table including a base and a primary plate attached to the base by a plurality of flexible posts that deflect to provide at least limited lateral displacement between the primary plate and the base in correspondence to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector coupled to at least one of the posts to detect deflection of the posts corresponding to the lateral displacement between the primary plate and the base; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

48. The method of claim 38, further comprising:

providing a planarizing machine having a table including a base and a primary plate attached to the base by a plurality of flexible posts that deflect to provide at least limited lateral displacement between the primary plate and the base in correspondence to the lateral drag forces, a carrier head to hold the substrate assembly, and a force detector contacting a stop surface of the base extending transverse to the planarizing surface and a contact surface of the primary plate adjacent to the stop surface to detect the lateral drag forces; and

wherein measuring the parameter indicative of drag force comprises sensing the lateral forces between the substrate assembly and the pad with the force detector.

49. The method of claim 38, further comprising determining the predetermined relationship between work and substrate thickness by measuring drag force between the substrate assembly and the polishing pad, measuring an actual thickness of the substrate assembly corresponding to each measured drag force to create work/thickness data points, and performing a mathematical regression of the data points to generate a straight-line association between work at the pad/substrate interface and thickness of the substrate assembly.

50. The method of claim 38 wherein estimating work at the pad/substrate interface further comprises:

measuring a parameter indicative of drag force between the substrate assembly and the polishing pad at periodic intervals to determine measured drag forces at the periodic intervals; and

determining an area under a line defined by a work versus time plot.

51. The method of claim 38 wherein estimating work at the pad/substrate interface comprises:

isolating a parameter indicative of drag force between the substrate assembly and the polishing pad that is not influenced by energy losses in components that drive either the polishing pad or the substrate assembly;

measuring the isolated parameter periodically to determine measured drag forces at periodic intervals; and

determining an area under a line defined by a work versus time plot.

52. The method of claim 38 wherein terminating removal of material from the substrate assembly further comprises:

determining the predetermined relationship between work and substrate thickness by measuring drag force between the substrate assembly and the polishing pad, measuring an actual thickness of the substrate assembly corresponding to each measured drag force to create work/thickness data points, and performing a mathematical regression of the data points to generate a straight-line association between work at the pad/substrate interface and thickness of the substrate assembly;

correlating the estimated work with the straight line relationship to determine ascertain an estimated thickness of the substrate assembly; and

disengaging the substrate assembly from the polishing pad when the estimated thickness of the substrate assembly is within a desired endpoint range.

38. A method of endpointing a mechanical and/or chemical-mechanical planarizing process for microelectronic substrate assemblies in which material is removed from a substrate assembly by rubbing at least one of a substrate assembly and a polishing pad against the other at a relative velocity, the substrate assembly contacting a planarizing surface of the polishing pad at a pad/substrate interface, the method comprising:

estimating total work exerted at the pad/substrate interface to rub the planarizing surface against the substrate assembly; and

terminating removal of material from the substrate assembly when the estimated work corresponds to a desired change in thickness of the substrate assembly according to a predetermined relationship between work and change in substrate assembly thickness.

53. A machine for planarizing a microelectronic-device substrate assembly, comprising:

a table having a bearing surface;

a polishing pad having a planarizing zone positioned over the bearing surface of the table, the polishing pad having a backside supported by the bearing surface and a planarizing surface in a planarizing plane;

a carrier assembly for controlling a substrate assembly, the carrier assembly having a head configured to hold the substrate assembly against the planarizing surface;

a drive system having a shaft pivotally coupled to one of the carrier head or the table to move at least one of the table or the carrier head in a lateral movement at least generally parallel to the planarizing plane to impart relative lateral motion between the substrate assembly and the polishing pad thereby generating lateral drag forces; and

an endpointing system including a force detector attached at a load site to at least one of the carrier head or the table, a computer readable medium programmed with a predetermined relationship between work exerted at a pad/substrate interface and thickness of the substrate assembly, and a computer programmed with an integration function being coupled to the force detector and the computer readable medium, the force detector being positioned at the load site to provide signals indicative of lateral drag forces to the computer, the computer integrating the product of the drag force signals and relative velocity over time to determine an estimated work exerted at the pad/substrate interface, and the computer correlating the estimated work with the predetermined relationship between work and substrate assembly thickness to ascertain an estimated thickness of the substrate assembly.