# US 10,770,327 B2 · System and method for correcting non-ideal wafer topography

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

- Number: US 10,770,327 B2
- Document ID: US10770327B2
- Status: Granted
- Kind: B2
- Application number: 15/941,568
- Filed: 2018-03-30
- Published: 2019-01-31
- Granted: 2020-09-08
- Earliest claimed: 2017-07-28
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Co., Ltd.
- Inventors: Cheng-Mu Lin; Chi-Hung Liao; Yi-Ming Dai; Yueh Lin Yang
- Web page: https://patentgrep.com/patent/US10770327B2

## CPC

- H10P 72/57: {Mask-wafer alignment}
- G06T 7/0004: {Industrial image inspection}
- H04N 23/56: provided with illuminating means
- H10P 72/0616: {Monitoring of warpages, curvatures, damages, defects or the like}
- H10P 72/53: {using optical controlling means}
- G06T 2207/10152: Varying illumination
- G06T 2207/30148: Semiconductor; IC; Wafer
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A scanner includes a light source configured to apply a light to a backside of a wafer. The light is reflected from the backside of the wafer. A first mirror is configured to receive the light from the backside of the wafer and reflect the light. A sensor is configured to receive the light from the first mirror and generate an output signal indicative of a backside topography of the wafer.

## Claims

### Claim 1

A scanner comprising:
a light source configured to apply a light to a backside of a wafer at a first adjustable incident angle with respect to a first horizontal axis;
a first mirror positioned to receive light reflected from a backside of a wafer when the light source is applied to the backside of the wafer and reflect the light, wherein a change in the first adjustable incident angle of ΔΘ corresponds to a horizontal movement of the first mirror Δx on a second horizontal axis parallel to the first horizontal axis; and
a sensor positioned to receive light reflected from the first mirror when the light source is applied to the backside of the wafer, wherein the sensor is configured to generate an output signal indicative of a backside topography of the wafer.

### Claim 2 (depends on 1)

The scanner of claim 1, wherein the light source is moveable on the first horizontal axis.

### Claim 3 (depends on 1)

The scanner of claim 1, wherein the first mirror reflects the light at a second adjustable incident angle with respect to the first horizontal axis.

### Claim 4 (depends on 1)

The scanner of claim 1, comprising a second mirror positioned to receive the light reflected from the first mirror and reflect the light to the sensor when the light is applied to the backside of the wafer.

### Claim 5 (depends on 4)

The scanner of claim 4, wherein the second mirror is horizontally aligned with the first mirror.

### Claim 6 (depends on 4)

The scanner of claim 4, wherein the second mirror is fixed.

### Claim 7 (depends on 1)

The scanner of claim 1, comprising a processor configured to receive the output signal from the sensor and generate a corrected overlay map.

### Claim 8 (depends on 7)

The scanner of claim 7, wherein the corrected overlay map is configured to correct for at least one non-linear overlay error.

### Claim 9 (depends on 7)

The scanner of claim 7, wherein the corrected overlay map is generated by combining an uncorrected overlay map and a topographical backside map, wherein the topographical backside map is generated from the output signal of the sensor.

### Claim 10 (depends on 1)

The scanner of claim 1, wherein the light is reflected from the backside of the wafer at a first angle and reflected from the first mirror at a second angle.

### Claim 11

A method, comprising:
applying a light from a light source to a first portion of a backside of a wafer at a first incident angle, wherein the backside of the wafer reflects the light;
reflecting the light applied at the first incident angle from the backside of the wafer to a sensor;
applying the light from the light source to a second portion of the backside of the wafer at a second incident angle;
reflecting the light applied at the second incident angle from the backside of the wafer to the sensor;
generating, by the sensor, a signal indicative of a backside topography of the wafer; and
generating a corrected overlay map based on the signal indicative of the backside topography of the wafer.

### Claim 12 (depends on 11)

The method of claim 11, comprising:
adjusting at least one of a horizontal position of a light source or a first mirror;
applying the light to a third portion of the backside of the wafer;
reflecting the light from the portion of the backside of the wafer to the sensor, wherein the signal indicative of the backside topography of the wafer includes backside topography of the first portion and the second portion of the backside of the wafer.

### Claim 13 (depends on 11)

The method of claim 11, comprising manufacturing one or more circuits on the wafer using the corrected overlay map.

### Claim 14 (depends on 11)

The method of claim 11, comprising:
reflecting the light from a first mirror to a second mirror; and
reflecting the light from the second mirror to the sensor.

### Claim 15 (depends on 14)

The method of claim 14, wherein the second mirror is horizontally aligned with the first mirror.

### Claim 16

A system, comprising:
a backside scanner comprising:
a light source configured to apply a light to a semiconductor wafer at a first adjustable incident angle with respect to a first horizontal axis;
a first mirror positioned to receive light reflected from the semiconductor wafer when the light source is applied to the semiconductor wafer and reflect the light, wherein a change in the first adjustable incident angle of ΔΘ corresponds to a horizontal movement of the first mirror Δx on a second horizontal axis parallel to the first horizontal axis; and
a sensor positioned to receive the light reflected from the first mirror when the light source is applied to the semiconductr wafer and generate an output signal indicative of a topography of the wafer;
a wafer table comprising a plurality of wafer supports extending from a top surface of the wafer table, wherein each of the plurality of wafer supports has a predetermined spacing and a predetermined height, and wherein the predetermined spacing, the predetermined height, or both of each the plurality of wafer supports has a variable value;
a processor configured to receive the output signal from the sensor and generate a corrected overlay map, wherein the corrected overlay map is configured to compensate for the variable value of each of the plurality of wafer supports; and
a semiconductor manufacturing system configured to form at least one layer of a semiconductor device on a semiconductor wafer coupled to the wafer table, wherein the corrected overlay map is configured to compensate for topography of the semiconductor wafer.

### Claim 17 (depends on 16)

The system of claim 16, wherein the light source is moveable on the first horizontal axis.

### Claim 18 (depends on 16)

The system of claim 16, wherein the wafer table is configured to support the semiconductor wafer with a backside of the semiconductor wafer oriented toward the backside scanner.

### Claim 19 (depends on 18)

The system of claim 18, comprising a second mirror configured to receive the light from the first mirror and reflect the light to the sensor, wherein the second mirror is horizontally aligned with the first mirror.

### Claim 20 (depends on 16)

The system of claim 16, wherein the corrected overlay map is generated by combining an uncorrected overlay map and a topographical map, wherein the topographical map is generated from the output signal of the sensor.