# US 6,293,846 B1 · Polishing apparatus

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 6,293,846 B1
- Document ID: US6293846B1
- Status: Granted
- Kind: B1
- Application number: 09/050,087
- Filed: 1998-03-30
- Granted: 2001-09-25
- Earliest claimed: 1997-06-17
- Assignees: Ebara Corporation
- Inventors: Shozo Oguri
- Web page: https://patentgrep.com/patent/US6293846B1

## CPC

- B24B 37/0053: {detecting loss or breakage of a workpiece during lapping}
- B24B 37/04: designed for working plane surfaces
- 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)
- B24B 55/00: Safety devices for grinding or polishing machines; Accessories fitted to grinding or polishing machines for keeping tools or parts of the machine in good working condition (of general applicability for machine tools B23Q11/00; in general F16P)
- H10P 95/00: Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass
- B24B: MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING (grinding of gear teeth B23F, of screw-threads B23G1/36; by electro-erosion B23H; abrasive or related blasting B24C; tools for grinding, buffing or sharpening B24D; polishing compositions C09G1/00; abrasives C09K3/14; electrolytic etching or polishing C25F3/00; grinding arrangements for use on assembled railway tracks E01B31/17); DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A polishing apparatus has a turntable having a polishing surface thereon, and a top ring for holding a workpiece and pressing the workpiece against the polishing surface of the turntable. The workpiece can be polished by the polishing surface of the turntable while the turntable and the top ring are being rotated. A workpiece dislodgment detector is provided to detect the workpiece which is dislodged from the top ring. The workpiece dislodgment detector has a sensor provided adjacent to the top ring, and the sensor is preferably positioned alongside of the top ring and downstream of the top ring with respect to a direction in which the turntable is rotated.

## Claims

### Claim 1

A polishing apparatus for polishing a workpiece, said apparatus comprising:
a turntable having a polishing surface;
a top ring for holding a workpiece and pressing the workpiece against said polishing surface of said turntable;
a workpiece dislodgment detector for detecting, during a polishing operation, the situation that the workpiece is dislodged from said top ring, said detector comprising a photoelectric gloss sensor for emitting light, receiving reflected light and detecting the workpiece that is dislodged from said top ring based on a change in a quantity of said reflected light, said sensor comprising a light-emitting diode for emitting light, a polarizing filter for allowing only S wave of the light from said light-emitting diode to pass therethrough, and a beam splitter for separating said reflected light into S wave and P wave, thus detecting the workpiece that is dislodged based on a difference in glossiness.

### Claim 2

A polishing apparatus for polishing a workpiece, said apparatus comprising:
a rotatable turntable having a polishing surface;
a single rotatable top ring for holding a single workpiece and pressing the workpiece against said polishing surface of said turntable;
said turntable and said top ring having respective configurations such that only a single workpiece at a time can be polished;
a workpiece dislodgment detector for, during a polishing operation, detecting the situation that the workpiece is dislodged from said top ring said detector comprising a photoelectric gloss sensor for emitting light, receiving reflected light and detecting the workpiece that is dislodged from said top ring based on a change in a quantity of said reflected light, said gloss sensor comprising a light-emitting diode for emitting light, a polarizing filter for allowing only S wave of the light from said light-emitting diode to pass therethrough, and a beam splitter for separating the reflected light into S wave and P wave, thus detecting the workpiece that is dislodged based on a difference in glossiness.

### Claim 3

A method for polishing a workpiece, said method comprising:
holding a single workpiece to be polished by a single top ring,, and pressing said single workpiece against a polishing surface of a turntable by said single top ring, while rotating said turntable and said single top ring, thereby polishing said workpiece;
detecting the situation of dislodgement of said workpiece from said top ring by a workpiece dislodgement detector comprising a gloss sensor for emitting light, receiving reflected light and detecting said workpiece that is dislodged from said top ring based on a change in a quantity of said reflected light; and
upon detection of a dislodged workpiece, lifting said top ring away from said turntable;
wherein the detecting of the situation of dislodgement of said workpiece from said top ring comprises:
(i) emitting light;
(ii) reflecting the emitted light from at least one of said polishing surface and said workpiece; and then
(iii) receiving the light at at least one of two receiving portions of said gloss sensor,
and wherein the receiving of the light comprises passing the reflected light through a beam splitter and
(a) receiving the light at a first one of the two receiving portions when the emitted light is reflected from a glossy one of said polishing surface and said workpiece, and
(b) receiving the light at a second one of the two receiving portions when the emitted light is reflected from a non-glossy one of said polishing surface and said workpiece.

### Claim 4 (depends on 3)

The method according to claim 3, wherein the passing of the reflected light through the beam splitter comprises separating the reflected light into S wave and P wave, with the S wave being received at the first one of the two receiving portions when the emitted light is reflected from a glossy one of said polishing surface and said workpiece, and with the P wave being received at the second one of the two receiving portions when the emitted light is reflected from a non-glossy one of said polishing surface and said workpiece.

### Claim 5

A method for polishing a workpiece, said method comprising:
holding a single workpiece to be polished by a single top ring, and pressing said single workpiece against a polishing surface of a turntable by said single top ring, while rotating said turntable and said single top ring, thereby polishing said workpiece;
detecting the situation of dislodgement of said workpiece from said top ring by a workpiece dislodgement detector comprising a gloss sensor for emitting light, receiving reflected light and detecting said workpiece that is dislodged from said top ring based on a change in a quantity of said reflected light; and
upon detection of a dislodged workpiece, stopping rotation of said turntable and rotation of said top ring;
wherein the detecting of the situation of dislodgement of said workpiece from said top ring comprises:
(i) emitting light;
(ii) reflecting the emitted light from at least one of said polishing surface and said workpiece; and then
(iii) receiving the light at at least one of two receiving portions of said gloss sensor,
and wherein the receiving of the light comprises passing the reflected light through a beam splitter and
(a) receiving the light at a first one of the two receiving portions when the emitted light is reflected from a glossy one of said polishing surface and said workpiece, and
(b) receiving the light at a second one of the two receiving portions when the emitted light is reflected from a non-glossy one of said polishing surface and said workpiece.

### Claim 6 (depends on 5)

The method according to claim 5, wherein the passing of the reflected light through the beam splitter comprises separating the reflected light into S wave and P wave, with the S wave being received at the first one of the two receiving portions when the emitted light is reflected from a glossly one of said polishing surface and said workpiece, and with the P wave being received at the second one of the two receiving portions when the emitted light is reflected from a non-glossy one of said polishing surface and said workpiece.

### Claim 7

A polishing apparatus for polishing a workpiece, said apparatus comprising:
a rotatable turntable having a polishing surface;
a single rotatable top ring for holding a single workpiece and pressing the workpiece against said polishing surface of said turntable;
said turntable and said top ring having a respective configurations such that only a single workpiece at a time can be polished; and
a workpiece dislodgement detector for, during a polishing operation, detecting the situation that the workpiece is dislodged from said top ring, said detector comprising a gloss sensor for emitting light, receiving reflected light and detecting the workpiece that is dislodged from said top ring based on a change in a quantity of said reflected light, wherein said gloss sensor includes a beam splitter for separating reflected light into S wave and P wave.

### Claim 8

A polishing apparatus for polishing a workpiece, said apparatus comprising:
a rotatable turntable having, a polishing surface;
a rotatable top ring for holding a workpiece and pressing the workpiece against said polishing
surface of said turntable;
a workpiece dislodgement detector for detecting, during a polishing operation, the situation that the workpiece is dislodged from said top ring, said detector comprising a gloss sensor for emitting light, receiving reflected light and detecting the workpiece that is dislodged from said top ring based on a change in a quantity of said reflected light, wherein said gloss sensor includes a beam splitter for separating reflected light into S wave and P wave; and
a mechanism, operable in response to said detector detecting a dislodged workpiece, for stopping rotation of said top ring and rotation of said turntable before said turntable has rotated a complete rotation.