# US 2008/0185102 A1 · Method and apparatus for real-time measurement of trace metal concentration in chemical mechanical polishing (cmp) slurry

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- Number: US 2008/0185102 A1
- Document ID: US20080185102A1
- Status: Published application
- Kind: A1
- Application number: 12/098,092
- Filed: 2008-04-04
- Published: 2008-08-07
- Earliest claimed: 2004-09-30
- Assignees: International Business Machines Corporation
- Inventors: Theodore G. Van Kessel
- Web page: https://patentgrep.com/patent/US20080185102A1

## CPC

- G01N 23/06: and measuring the absorption
- G01N 23/223: by irradiating the sample with X-rays or gamma-rays and by measuring X-ray fluorescence
- G01N 2223/076: X-ray fluorescence
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A system (and method) for real-time measurement of trace metal concentration in a chemical mechanical polishing (CMP) slurry, includes an electromagnetic radiation flow cell carrying a CMP slurry, a slurry pickup head coupled to the flow cell, and an analyzer for measuring properties of the slurry flowing through the flow cell.

## Claims

### Claim 1

A system for real-time measurement of trace predetermined material concentration in a chemical mechanical polishing (CMP) slurry, comprising:
a CMP slurry flow cell analyzer for determining at least one of transmission and fluorescent properties of a slurry flowing through the cell; and
a slurry pickup pumping head coupled to said flow cell.

### Claim 2 (depends on 1)

The system of claim 1, further comprising:
a radiation source for illuminating said slurry.

### Claim 3 (depends on 1)

The system of claim 1, wherein said analyzer includes a bent crystal analyzer.

### Claim 4 (depends on 3)

The system of claim 3, wherein said analyzer further includes a detector for receiving and measuring a quantity of photons from said bent crystal analyzer.

### Claim 5 (depends on 4)

The system of claim 4, wherein said detector comprises a SiLi detector.

### Claim 6 (depends on 4)

The system of claim 4, wherein said processor receives an output from said detector for providing any of a slurry concentration signal and an endpoint signal.

### Claim 7 (depends on 1)

The system of claim 1, further comprising:
a pump coupled to said flow cell.

### Claim 8 (depends on 1)

The system of claim 1, wherein said slurry is removed one of from a polishing pad using said pickup head, and a direct connection through said flow cell to a polishing pad drain.

### Claim 9 (depends on 1)

The system of claim 1, wherein the slurry is piped through said flow cell, said flow cell comprising a plastic tube transparent to said electromagnetic radiation.

### Claim 10 (depends on 4)

The system of claim 4, further comprising:
an electromagnetic radiation source for illuminating the flow cell, wherein photons traveling through the tube produce fluorescent rays in a predetermined material atoms contained in the slurry.

### Claim 11 (depends on 10)

The system of claim 10, wherein the detector of the flow cell analyzer receives said fluorescent rays.

### Claim 12 (depends on 4)

The system of claim 4, further comprising:
a detector shield positioned adjacent the flow cell for shielding the detector from any of stray and scattered photons from other than the desired locations.

### Claim 13 (depends on 4)

The system of claim 4, wherein adjustment to an angle of a crystal of the bent crystal analyzer is provided such that only photons with an energy of interest are directed to the detector.

### Claim 14 (depends on 13)

The system of claim 13, further comprising:
a baffle for allowing only predetermined ones of said photons to be passed therethrough to the detector.

### Claim 15 (depends on 1)

The system of claim 1, said slurry being usable by a polishing tool, wherein data representing an interpretation of the measured characteristic emissions of the slurry is output from the processor to the polishing tool.

### Claim 16 (depends on 1)

The system of claim 1, wherein the system determines a process endpoint based on detected trace materials.

### Claim 17 (depends on 1)

The system of claim 1, wherein the trace predetermined material concentration is measured without regard for slurry particles.

### Claim 18

A material concentration measurement system, comprising:
a slurry flow cell for having a slurry flow therethrough;
a radiation source for illuminating said slurry, such that radiation traveling through the flow cell produces fluorescence in predetermined material atoms contained in the slurry; and
an analyzer for measuring, in real-time, a concentration of trace predetermined material atoms in the slurry in response to the fluorescence.

### Claim 19

A system for real-time measurement of trace metal concentration in a chemical mechanical polishing (CMP) slurry, comprising:
an optical flow cell for having a CMP slurry flow therethrough; and
a slurry pickup head operatively coupled to said optical flow cell.