Polishing apparatus including thickness or flatness detector

Claim 2

A polishing apparatus comprising: a turntable having thereon a polishing surface; a top ring disposed above said turntable for supporting a workpiece to be polished and for pressing the workpiece against said polishing surface; and a thickness detector operable to, during relative movement between said top ring and said turntable, detect a thickness of a surface layer of the workpiece by performing a plurality of thickness detection operations over time and thereby to detect the thickness of the entire surface layer of the workpiece, each said thickness detection operation comprising detecting thickness of the surface layer at a plurality of spots spaced radially of said turntable at one time on a real-time basis, said thickness detector including a sensor mounted in said turntable at a position within a path of relative movement between said top ring and said turntable and operable to perform said plurality of thickness detection operations over time, said sensor comprising a plurality light-emitting elements operable to emit respective light beams toward the surface layer of the workpiece and a plurality of light-detecting elements operable to detect respective of the light beams reflected from the surface layer of the workpiece, said plurality of said light-emitting elements and said plurality of said light-detecting elements being spaced radially of said turntable, said light-detecting elements generating signals representative of detected thickness at said plurality of spots, and said signals being processed together to determine the thickness of the surface layer of the workpiece.

Claim 3

A polishing apparatus as claimed in claim 1, wherein said polishing surface comprises a polishing cloth having therein a hole for passing therethrough the light beams emitted from said light-emitting elements and the light beams reflected from the surface layer of the workpiece.

Claim 4

A polishing apparatus as claimed in claim 1, wherein said thickness detector is operable to detect the thickness of the surface layer of the workpiece based on a change in the intensity of the light beams reflected from the surface layer and detected by said light-detecting elements.

Claim 5

A polishing apparatus as claimed in claim 1, wherein said thickness detector is operable to detect flatness of the surface layer of the workpiece based on said plurality of thickness detection operations.

Claim 6

A polishing apparatus as claimed in claim 4, wherein said thickness detector is operable to end a polishing process of said polishing apparatus when the flatness of the surface layer of the workpiece detected by said thickness detector reaches a predetermined flatness.

Claim 7

A polishing apparatus as claimed in claim 1, wherein said thickness detector is operable to end a polishing process of said polishing apparatus when the thickness of the surface layer of the workpiece detected by said thickness detector reaches a predetermined thickness.

Claim 8

A polishing apparatus as claimed in claim 1, wherein said thickness detector is operable to calculate a polishing rate of the workpiece on the basis of the thickness of the surface layer of the workpiece detected by said thickness detector and an elapsed time during which a polishing process is effected.

Claim 9

A polishing apparatus as claimed in claim 1, wherein said polishing surface comprises a polishing cloth including a sectorial region extending radially and having one of a low abrasion capability and no abrasion capability, said sensor being positioned in said sectorial region.

Claim 10

A polishing apparatus as claimed in claim 1, wherein said thickness detector further comprises an amplifier for amplifying said signals generated by said light-detecting elements, an analog filter for removing noise from said signals amplified by said amplifier, an analog-to-digital converter for converting said signals into digital signals, and a computing unit for calculating an absolute value of a difference between said digital signals and an initial value and for comparing the thus calculated absolute value of said difference with a predetermined threshold value to produce resultant data.

Claim 11

A polishing apparatus as claimed in claim 9, wherein said thickness detector further comprises a controller for controlling operating parameters of said polishing apparatus based on said resultant data produced by said computing unit.

Claim 12

A polishing apparatus as claimed in claim 1, wherein said thickness detector is operable to control operating parameters of said polishing apparatus based on the detected thickness of the surface layer of the workpiece.

Claim 13

A polishing apparatus as claimed in claim 11, wherein said operating parameters include at least one of a pressure exerted on said top ring and rotational speeds of said turntable and said top ring.

Claim 14

A polishing apparatus as claimed in claim 11, wherein said operating parameters include a pressure applied to an upper surface of the workpiece.

Claim 15

A polishing apparatus as claimed in claim 11, further comprising means for rotating said turntable and said top ring about respective axes thereof to thereby provide said relative movement therebetween.

Claim 16

A polishing apparatus comprising: a turntable having thereon a polishing surface; a top ring disposed above said turntable for supporting a workpiece to be polished and for pressing the workpiece against said polishing surface; and a thickness detector operable to, during relative movement between said top ring and said turntable, detect a thickness of a surface layer of the workpiece by performing a plurality of thickness detection operations over time and thereby to detect the thickness of the entire surface layer of the workpiece, each said thickness detection operation comprising detecting thickness of the surface layer at a plurality of spots spaced radially of said turntable at one time on a real-time basis, said thickness detector comprising: a sensor mounted in said turntable at a position within a path of relative movement between said top ring and said turntable and operable to perform said plurality of thickness detection operations over time, said sensor comprising a plurality light-emitting elements operable to emit respective light beams toward the surface layer of the workpiece and a plurality of light-detecting elements operable to detect respective of the light beams reflected from the surface layer of the workpiece, said plurality of said light-emitting elements and said plurality of said light-detecting elements being spaced radially of said turntable, and said light-detecting elements generating signals representative of detected thickness at said plurality of spots; and means for determining the thickness of the surface layer of the workpiece by processing together said signals from said light-detecting elements.

Claim 17

A polishing apparatus comprising: a turntable having thereon a polishing surface; a top ring disposed above said turntable for supporting a workpiece to be polished and for pressing the workpiece against said polishing surface; and a thickness detector operable to, during relative movement between said top ring and said turntable, detect a thickness of a surface layer of the workpiece by performing a plurality of thickness detection operations over time and thereby to detect the thickness of the entire surface layer of the workpiece, each said thickness detection operation comprising detecting thickness of the surface layer at a plurality of spots spaced radially of said turntable at one time on a real-time basis, said thickness detector comprising: a sensor mounted in said turntable at a position within a path of relative movement between said top ring and said turntable and operable to perform said plurality of thickness detection operations over time, said sensor comprising a plurality light-emitting elements operable to emit respective light beams toward the surface layer of the workpiece and a plurality of light-detecting elements operable to detect respective of the light beams reflected from the surface layer of the workpiece, said plurality of said light-emitting elements and said plurality of said light-detecting elements being spaced radially of said turntable, and said light-detecting elements generating signals representative of detected thickness at said plurality of spots; and means for determining the thickness of the surface layer of the workpiece by processing together said signals from said light-detecting elements.

Claim 18

A polishing apparatus as claimed in claim 15, wherein said polishing surface comprises a polishing cloth having therein a hole for passing therethrough the light beams emitted from said light-emitting elements and the light beams reflected from the surface layer of the workpiece.

Claim 19

A polishing apparatus as claimed in claim 15, wherein said thickness detector is operable to detect the thickness of the surface layer of the workpiece based on a change in the intensity of the light beams reflected from the surface layer and detected by said light-detecting elements.

Claim 20

A polishing apparatus as claimed in claim 15, wherein said thickness detector is operable to detect flatness of the surface layer of the workpiece based on said plurality of thickness detection operations.

Claim 21

A polishing apparatus as claimed in claim 18, wherein said thickness detector is operable to end a polishing process of said polishing apparatus when the flatness of the surface layer of the workpiece detected by said thickness detector reaches a predetermined flatness.

Claim 22

A polishing apparatus as claimed in claim 15, wherein said thickness detector is operable to end a polishing process of said polishing apparatus when the thickness of the surface layer of the workpiece detected by said thickness detector reaches a predetermined thickness.

Claim 23

A polishing apparatus as claimed in claim 15, wherein said thickness detector is operable to calculate a polishing rate of the workpiece on the basis of the thickness of the surface layer of the workpiece detected by said thickness detector and an elapsed time during which a polishing process is effected.

Claim 24

A polishing apparatus as claimed in claim 15, wherein said polishing surface comprises a polishing cloth including a sectorial region extending radially and having one of a low abrasion capability and no abrasion capability, said sensor being positioned in said sectorial region.

Claim 25

A polishing apparatus as claimed in claim 15, wherein said means for determining comprises an amplifier for amplifying said signals generated by said light-detecting elements, an analog filter for removing noise from said signals amplified by said amplifier, an analog-to-digital converter for converting said signals into digital signals, and a computing unit for calculating an absolute value of a difference between said digital signals and an initial value and for comparing the thus calculated absolute value of said difference with a predetermined threshold value to produce resultant data.

Claim 26

A polishing apparatus as claimed in claim 23, wherein said thickness detector further comprises a controller for controlling operating parameters of said polishing apparatus based on said resultant data produced by said computing unit.

Claim 27

A polishing apparatus as claimed in claim 15, wherein said thickness detector is operable to control operating parameters of said polishing apparatus based on the determined thickness of the surface layer of the workpiece.

Claim 28

A polishing apparatus as claimed in claim 25, wherein said operating parameters include at least one of a pressure exerted on said top ring and rotational speeds of said turntable and said top ring.

Claim 29

A polishing apparatus as claimed in claim 25, wherein said operating parameters include a pressure applied to an upper surface of the workpiece.

Claim 30

A polishing apparatus as claimed in claim 15, further comprising means for rotating said turntable and said top ring about respective axes thereof to thereby provide said relative movement therebetween.

Claim 31

A polishing apparatus comprising: a turntable having thereon a polishing surface; a top ring disposed above said turntable for supporting a workpiece to be polished and for pressing the workpiece against said polishing surface; and a thickness detector operable to, during relative movement between said top ring and said turntable, detect a flatness of a surface layer of the workpiece by performing a plurality of thickness detection operations over time and thereby to detect the flatness of the entire surface layer of the workpiece, each said thickness detection operation comprising detecting thickness of the surface layer at a plurality of spots spaced radially of said turntable at one time on a real-time basis, said thickness detector comprising: a sensor mounted in said turntable at a position within a path of relative movement between said top ring and said turntable and operable to perform said plurality of thickness detection operations over time, said sensor comprising a plurality light-emitting elements operable to emit respective light beams toward the surface layer of the workpiece and a plurality of light-detecting elements operable to detect respective of the light beams reflected from the surface layer of the workpiece, said plurality of said light-emitting elements and said plurality of said light-detecting elements being spaced radially of said turntable, and said light-detecting elements generating signals representative of detected thickness at said plurality of spots; and means for determining the flatness of the surface layer of the workpiece by processing together said signals from said light-detecting elements.

Claim 32

A polishing apparatus comprising: a turntable having thereon a polishing surface; a top ring disposed above said turntable for supporting a workpiece to be polished and for pressing the workpiece against said polishing surface; and a thickness detector operable to, during relative movement between said top ring and said turntable, detect a flatness of a surface layer of the workpiece by performing a plurality of thickness detection operations over time and thereby to detect the flatness of the entire surface layer of the workpiece, each said thickness detection operation comprising detecting thickness of the surface layer at a plurality of spots spaced radially of said turntable at one time on a real-time basis, said thickness detector comprising: a sensor mounted in said turntable at a position within a path of relative movement between said top ring and said turntable and operable to perform said plurality of thickness detection operations over time, said sensor comprising a plurality light-emitting elements operable to emit respective light beams toward the surface layer of the workpiece and a plurality of light-detecting elements operable to detect respective of the light beams reflected from the surface layer of the workpiece, said plurality of said light-emitting elements and said plurality of said light-detecting elements being spaced radially of said turntable, and said light-detecting elements generating signals representative of detected thickness at said plurality of spots; and means for determining the flatness of the surface layer of the workpiece by processing together said signals from said light-detecting elements.

Claim 33

A polishing apparatus as claimed in claim 29, wherein said polishing surface comprises a polishing cloth having therein a hole for passing therethrough the light beams emitted from said light-emitting elements and the light beams reflected from the surface layer of the workpiece.

Claim 34

A polishing apparatus as claimed in claim 29, wherein said thickness detector is operable to detect the flatness of the surface layer of the workpiece based on a change in the intensity of the light beams reflected from the surface layer and detected by said light-detecting elements.

Claim 35

A polishing apparatus as claimed in claim 29, wherein said thickness detector is operable to end a polishing process of said polishing apparatus when the flatness of the surface layer of the workpiece detected by said thickness detector reaches a predetermined flatness.

Claim 36

A polishing apparatus as claimed in claim 29, wherein said polishing surface comprises a polishing cloth including a sectorial region extending radially and having one of a low abrasion capability and no abrasion capability, said sensor being positioned in said sectorial region.

Claim 37

A polishing apparatus as claimed in claim 29, wherein said means for determining comprises an amplifier for amplifying said signals generated by said light-detecting elements, an analog filter for removing noise from said signals amplified by said amplifier, an analog-to-digital converter for converting said signals into digital signals, and a computing unit for calculating an absolute value of a difference between said digital signals and an initial value and for comparing the thus calculated absolute value of said difference with a predetermined threshold value to produce resultant data.

Claim 38

A polishing apparatus as claimed in claim 34, wherein said thickness detector further comprises a controller for controlling operating parameters of said polishing apparatus based on said resultant data produced by said computing unit.

Claim 39

A polishing apparatus as claimed in claim 29, wherein said thickness detector is operable to control operating parameters of said polishing apparatus based on the determined flatness of the surface layer of the workpiece.

Claim 40

A polishing apparatus as claimed in claim 36, wherein said operating parameters include at least one of a pressure exerted on said top ring and rotational speeds of said turntable and said top ring.

Claim 41

A polishing apparatus as claimed in claim 36, wherein said operating parameters include a pressure applied to an upper surface of the workpiece.

Claim 42

A polishing apparatus as claimed in claim 29, further comprising means for rotating said turntable and said top ring about respective axes thereof to thereby provide said relative movement therebetween.