# US 8,465,590 B2 · Emissivity profile control for thermal uniformity

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- Number: US 8,465,590 B2
- Document ID: US8465590B2
- Status: Granted
- Kind: B2
- Application number: 13/019,268
- Filed: 2011-02-01
- Published: 2012-08-02
- Granted: 2013-06-18
- Earliest claimed: 2011-02-01
- Assignees: Intermolecular, Inc.
- Applicants: Rajesh Kelekar
- Inventors: Rajesh Kelekar
- Web page: https://patentgrep.com/patent/US8465590B2

## CPC

- H10P 95/90: Thermal treatments, e.g. annealing or sintering
- H05B 6/105: {using a susceptor}
- H10P 72/0434: {mainly by convection}
- H10P 72/0436: {mainly by radiation}
- H10P 72/7616: {characterised by a coating, a hardness or a material}
- H10P 90/00: Preparation of wafers not covered by a single main group of this subclass, e.g. wafer reinforcement
- H10P 90/1904: {Preparing vertically inhomogeneous wafers}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL

## Abstract

A substrate for processing in a heating system is disclosed. The substrate includes a bottom portion for absorbing heat from a radiating heat source, the bottom portion having a first region having a first emissivity and a second region having a second emissivity less than the first emissivity. The first region and the second region promote thermal uniformity of the substrate by compensating for thermal non-uniformity of the radiating heat source.

## Claims

### Claim 1

A susceptor for heating a substrate in an induction heating system, said susceptor having a top surface for transmitting heat to the substrate, the top surface having multiple regions including at least a first region having a first emissivity and a second region having a second emissivity different than the first emissivity
wherein the second region has a thin film coating deposited thereon;
wherein the first region comprises a graphite material; and
wherein the thin film coating comprises a metallic material selected from the group consisting of silver, copper, or molybdenum.

### Claim 2 (depends on 1)

The susceptor of claim 1, wherein the first region and the second region promote uniform thermal transmission across the top surface of the susceptor, the uniform thermal transmission defined by a temperature variation in the substrate of less than approximately 100 K when heated by the susceptor to a temperature range of 1000 k to 2000 K.

### Claim 3 (depends on 1)

The susceptor of claim 1, wherein the surface roughness of the second region is less than the surface roughness of the first region.

### Claim 4 (depends on 1)

The susceptor of claim 1, wherein the first region and the second region are radially symmetric.

### Claim 5 (depends on 1)

The susceptor of claim 1, wherein the induction heating system includes an RF coil formed as a planar spiral, the first emissivity of the first region and the second emissivity of the second region compensating for non-uniform inductive heating of the susceptor by the RF coil.

### Claim 6

A method for heating a substrate in an induction heating system, comprising:
disposing a substrate above a susceptor;
inductively heating the susceptor, the inductive heating providing non-uniform heating of the susceptor;
compensating for the non-uniform heating of the susceptor to provide substantially uniform heating of the substrate, the compensating comprising performing one of variably absorbing heat at a bottom surface of the substrate or variably transmitting heat of the susceptor at a top surface of the susceptor;
wherein variably absorbing heat at the bottom surface of the substrate includes absorbing heat through a first bottom surface portion having a first emissivity and absorbing heat through a second bottom surface portion having a second emissivity less than the first emissivity.

### Claim 7 (depends on 6)

The method of claim 6, wherein the second bottom surface portion comprises an annular ring surrounding the first bottom surface portion.

### Claim 8 (depends on 6)

The method of claim 6,
wherein variably transmitting heat of the susceptor at the top surface of the susceptor includes transmitting heat through a first top surface portion having a first emissivity and transmitting heat through a second top surface portion having a second emissivity less than the first emissivity.

### Claim 9 (depends on 8)

The method of claim 8, wherein the second top surface portion comprises an annular ring surrounding the first top surface portion.

### Claim 10 (depends on 6)

The method of claim 6, wherein the substantially uniform heating of the substrate is defined by a temperature variation of less than approximately 100 K when the substrate is heated to a temperature range of approximately 1000 K to 2000 K.

### Claim 11 (depends on 6)

The method of claim 6, wherein inductively heating the susceptor includes applying a current to an RF coil.