# US 9,752,981 B2 · Apparatus with a spectral reflectometer for processing substrates

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

- Number: US 9,752,981 B2
- Document ID: US9752981B2
- Status: Granted
- Kind: B2
- Application number: 15/089,214
- Filed: 2016-04-01
- Published: 2016-11-03
- Granted: 2017-09-05
- Earliest claimed: 2015-04-30
- Assignees: Lam Research Corporation
- Applicants: Lam Research Corporation
- Inventors: Seonkyung Lee; Dmitry Opaits
- Web page: https://patentgrep.com/patent/US9752981B2

## CPC

- G01N 21/55: Specular reflectivity
- G01N 21/272: {for following a reaction, e.g. for determining photometrically a reaction rate (photometric cinetic analysis)}
- H01J 37/00: Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof (H01J33/00, H01J40/00, H01J41/00, H01J47/00, H01J49/00 take precedence)
- H01J 37/32972: {Spectral analysis}
- G01N 2021/8411: {Application to online plant, process monitoring}
- G01N 2201/0633: Directed, collimated illumination
- G01N 2201/08: Optical fibres; light guides
- G01N 2201/1222: Endpoint determination; reaction time determination
- 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)
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

A spectral reflectometer system for measuring a substrate is provided. A light source is provided. At least one optical detector is provided. An optical cable comprises a plurality of optical fibers, wherein the plurality of optical fibers comprises a first plurality of optical fibers, which are transmission optical fibers which extend from the light source to an optical path, and a second plurality of optical fibers, which are reflection optical fibers which extend from the optical path to the at least one optical detector. A microlens array is in the optical path.

## Claims

### Claim 1

A spectral reflectometer system for measuring a substrate in a processing chamber, comprising
a light source;
at least one optical detector;
an optical cable, comprising a plurality of optical fibers, wherein the plurality of optical fibers comprises a first plurality of optical fibers, which are transmission optical fibers which extend from the light source to a first portion of a housing supporting the optical cable, and a second plurality of optical fibers, which are reflection optical fibers which extend from the first portion of the housing to the at least one optical detector;
a second portion of the housing including an optical path for light to traverse through the second portion of the housing; and
a microlens array in the optical path of the second portion of the housing;
wherein the housing transmits light from the light source to an illuminated portion of the substrate and collects reflected light from the illuminated portion of the substrate.

### Claim 2 (depends on 1)

The spectral reflectometer system, as recited in claim 1, wherein the microlens array decreases spatial distortions including at least one of optical fiber spatial distortion, light source spatial distortion, and collimator spatial distortion.

### Claim 3 (depends on 1)

The spectral reflectometer system, as recited in claim 1, wherein the microlens array comprises a plurality of microlens, wherein each microlens of the plurality of microlens has a focal plane, and wherein the illuminated portion of the substrate does not lie on any focal plane of the plurality of microlens so that transmitted light from the light source is blurred on the illuminated portion of the substrate.

### Claim 4 (depends on 1)

The spectral reflectometer system, as recited in claim 1, wherein the microlens array is spaced apart from the optical cable.

### Claim 5 (depends on 4)

The spectral reflectometer system, as recited in claim 4, wherein the at least one optical detector provides an output as a function of wavelength.

### Claim 6 (depends on 5)

The spectral reflectometer system, as recited in claim 5, further comprising a collimator lens in the second optical path, wherein the collimator lens is spaced apart from the microlens array.

### Claim 7 (depends on 6)

The spectral reflectometer system, as recited in claim 6, wherein the light source provides a pulsed light.

### Claim 8 (depends on 6)

The spectral reflectometer system, as recited in claim 6, wherein the light source provides a continuous wave light.

### Claim 9 (depends on 1)

The spectral reflectometer system, as recited in claim 1, wherein at least part of the optical path is substantially perpendicular to the illuminated portion of the substrate, wherein some light reflected from the illuminated portion passes through the microlens array to the optical detector.

### Claim 10 (depends on 1)

The spectral reflectometer system, as recited in claim 1, wherein the at least one optical detector provides an output as a function of wavelength.

### Claim 11 (depends on 1)

The spectral reflectometer system, as recited in claim 1, wherein the light source is a non-uniform light source.

### Claim 12 (depends on 1)

The spectral reflectometer system, as recited in claim 1, wherein the light source is a pulsed Xenon arc lamp.

### Claim 13 (depends on 1)

The spectral reflectometer system, as recited in claim 1, further comprising:
a processing chamber;
a substrate support for supporting the substrate within the processing chamber;
a gas source;
a gas inlet connected between the gas source and the processing chamber;
a power source;
at least one electrode adjacent to the processing chamber and electrically connected to the power source; and
a controller controllably connected to the power source and gas source, and the at least one optical detector, wherein the controller comprises:
at least one central processing unit; and
computer readable media, comprising:
computer readable code for using output from the at least one optical detector to detect an endpoint; and
computer readable code for changing settings of the power source or gas source when an endpoint is detected.

### Claim 14 (depends on 1)

The spectral reflectometer system, as recited in claim 1, further comprising an optical assembly in the optical path.

### Claim 15

An apparatus for processing a substrate, comprising:
a processing chamber;
a substrate support for supporting the substrate within the processing chamber; and
a spectral reflectometer system, comprising:
a light source;
at least one optical detector;
an optical cable, comprising a plurality of optical fibers, wherein the plurality of optical fibers comprises a first plurality of optical fibers, which are transmission optical fibers which extend from the light source to an optical path, and a second plurality of optical fibers, which are reflection optical fibers which extend from the optical path to the at least one optical detector;
a microlens array in the optical path, wherein the microlens array comprises a plurality of microlens; and
an optical assembly supported across the optical path, wherein the optical path is positioned to provide light from the light source to an illuminated portion of the substrate and collect reflected light from the illuminated portion of the substrate, wherein light from the light source and reflected light pass through the microlens array, wherein each microlens of the plurality of microlens has a focal plane, and wherein the illuminated portion of the substrate does not lie on any focal plane of the plurality of microlens.

### Claim 16 (depends on 15)

The apparatus, as recited in claim 15, further comprising:
a gas source;
a gas inlet connected between the gas source and the processing chamber;
a power source;
at least one electrode adjacent to the processing chamber and electrically connected to the power source; and
a controller controllably connected to the power source and gas source, and the at least one optical detector, wherein the controller comprises:
at least one central processing unit; and
computer readable media, comprising:
computer readable code for using output from the at least one optical detector to detect an endpoint; and
computer readable code for changing settings of the power source or gas source when an endpoint is detected.

### Claim 17 (depends on 16)

The apparatus, as recited in claim 16, wherein the at least one optical detector provides an output as a function of wavelength.