# US 10,121,914 B2 · Back-illuminated sensor with boron layer

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- Number: US 10,121,914 B2
- Document ID: US10121914B2
- Status: Granted
- Kind: B2
- Application number: 15/797,970
- Filed: 2017-10-30
- Published: 2018-02-15
- Granted: 2018-11-06
- Earliest claimed: 2012-04-10
- Assignees: KLA-Tencor Corporation
- Applicants: KLA-Tencor Corporation
- Inventors: Jehn-Huar Chern; Ali R. Ehsani; Gildardo Delgado; David L. Brown; Yung-Ho Alex Chuang; John Fielden
- Web page: https://patentgrep.com/patent/US10121914B2

## CPC

- H10F 77/30: Coatings (arrangements for preventing damage to photovoltaic cells caused by corpuscular radiation H10F77/80)
- G01N 21/8806: {Specially adapted optical and illumination features}
- G01N 21/9501: {Semiconductor wafers (manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)}
- G01N 21/956: Inspecting patterns on the surface of objects {(contactless testing of electronic circuits G01R31/308; testing currency G07D; manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)}
- H10F 39/024: {of coatings or optical elements}
- H10F 39/199: {Back-illuminated image sensors}
- H10F 39/80: {Constructional details of image sensors}
- H10F 39/8033: {Photosensitive area}
- H10F 39/805: {Coatings}
- G01N 2021/95676: {Masks, reticles, shadow masks}
- H10F 39/014: {of CMOS image sensors}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- 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

An inspection system including an optical system (optics) to direct light from an illumination source to a sample, and to direct light reflected/scattered from the sample to one or more image sensors. At least one image sensor of the system is formed on a semiconductor membrane including an epitaxial layer having opposing surfaces, with circuit elements formed on one surface of the epitaxial layer, and a pure boron layer on the other surface of the epitaxial layer. The image sensor may be fabricated using CCD (charge coupled device) or CMOS (complementary metal oxide semiconductor) technology. The image sensor may be a two-dimensional area sensor, or a one-dimensional array sensor. The image sensor can be included in an electron-bombarded image sensor and/or in an inspection system.

## Claims

### Claim 1

A system for inspecting a sample, the system comprising:
at least one illumination relay configured to direct light generated by an illumination source onto the sample;
image relay optics configured to direct light outputs from the sample to at least one channel image mode relay; and
an image sensor configured to receive said light outputs from the channel image mode relay, the sensor including an image region including pixels disposed in a two-dimensional array on an epitaxial silicon membrane, the epitaxial silicon membrane including readout circuit elements formed on a first surface of the epitaxial silicon membrane and a pure boron layer disposed on an opposing second surface,
wherein the system is configured such that the readout circuit elements read out charges from the pixels that correspond to the light outputs directed onto the image region by the channel image mode relay.

### Claim 2 (depends on 1)

The inspection system of claim 1,
wherein said at least one illumination relay comprises a first illumination relay configured to direct a first portion of the light generated by said illumination source to the sample, and a second illumination relay configured to direct a second portion of the light generated by said illumination source to the sample, and
wherein said at least one channel image mode relay comprises:
a first channel image mode relay configured to detect said first portion of said light that are either reflected from said sample or transmitted through said sample, and
a second channel image mode relay configured to detect said second portion of said light that are either reflected from said sample or transmitted through said sample.

### Claim 3 (depends on 1)

The inspection system of claim 1,
wherein the image region includes a first plurality of said pixels disposed in a first side region and second plurality of said pixels disposed in a second side region, and
wherein the image sensor is configured such that a first group of said readout circuit elements reads out charges from the first plurality of said pixels while a second group of said readout circuit elements reads out charges from the second plurality of said pixels.

### Claim 4 (depends on 1)

The inspection system of claim 1, wherein each pixel of the image sensor comprises a p-type silicon layer and n-type silicon layer, and wherein said circuit elements are formed on the n-type silicon layer and said pure boron layer being disposed on the p-type silicon layer.

### Claim 5

An inspection system for inspecting a sample, the inspection system comprising:
an illumination source configured to generate light;
optics including an objective lens, the optics configured to direct and focus said light generated by the illumination source onto the sample;
a detector configured to receive portions of the light redirected from the sample, and to output detector data based on said received portions of the light for analysis by a computing system,
wherein the optics are further configured to collect, direct, and focus the redirected light onto the detector, and
wherein the detector includes an array of image sensors, at least one image sensor in the array of image sensors including an image region including pixels disposed in one of a one-dimensional array and a two-dimensional array on an epitaxial silicon membrane having opposing first and second surfaces, the epitaxial silicon membrane including readout circuit elements formed on the first surface and configured to generate said detector data based on said received portions of the light, and the epitaxial silicon membrane including a pure boron layer disposed on the opposing second surface.

### Claim 6 (depends on 5)

The inspection system of claim 5,
wherein the array of image sensors include a first row of space-apart image sensors and a second row of spaced-apart image sensors, and
wherein said first row is offset relative to said second row such that a first image sensor of said first row is aligned with a space separating second and third image sensors of the second row.

### Claim 7 (depends on 6)

The inspection system of claim 6, wherein a width of the first sensor is equal to or greater than the space separating the second and third image sensors.

### Claim 8 (depends on 5)

The inspection system of claim 5, wherein the at least one image sensor further comprises an anti-reflection coating deposited on the boron layer.

### Claim 9 (depends on 5)

The inspection system of claim 5, wherein the illumination source comprises a laser-pumped plasma light source.

### Claim 10

An inspection system comprising:
an illumination source configured to generate light;
optics including an objective lens, the optics configured to direct and focus said light generated by the illumination source onto one of a line-shaped region of the sample and multiple spot-type regions on the sample;
a detector configured to receive portions of the light redirected from the sample,
wherein the optics are further configured to collect, direct, and focus the redirected light onto the detector, and
wherein the detector includes an image sensor formed on a semiconductor membrane including an epitaxial layer having opposing first and second surfaces, said image sensor including an image region including pixels disposed in one of a one-dimensional array and a two-dimensional array on the first surface of the epitaxial silicon membrane, and a pure boron layer disposed on the opposing second surface of the epitaxial layer.

### Claim 11 (depends on 10)

The inspection system of claim 10, wherein the image sensor comprises a line sensor.

### Claim 12 (depends on 11)

The inspection system of claim 11, wherein the line sensor comprises an electron-bombarded line sensor.

### Claim 13 (depends on 10)

The inspection system of claim 10, wherein the image sensor comprises a two-dimensional array sensor.

### Claim 14 (depends on 13)

The inspection system of claim 13, wherein the image sensor comprises an electron-bombarded two-dimensional array sensor.