# US 10,373,809 B2 · Grooved backing plate for standing wave compensation

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- Number: US 10,373,809 B2
- Document ID: US10373809B2
- Status: Granted
- Kind: B2
- Application number: 15/274,608
- Filed: 2016-09-23
- Published: 2017-03-30
- Granted: 2019-08-06
- Earliest claimed: 2015-09-25
- Assignees: Applied Materials, Inc.
- Applicants: Applied Materials, Inc.
- Inventors: Shinichi Kurita; Robin L. Tiner
- Web page: https://patentgrep.com/patent/US10373809B2

## CPC

- H01J 37/32431: {Constructional details of the reactor}
- C23C 16/458: characterised by the method used for supporting substrates in the reaction chamber
- C23C 16/505: using radio frequency discharges
- C23C 16/5096: {Flat-bed apparatus}
- H01J 37/32091: {the radio frequency energy being capacitively coupled to the plasma}
- H01J 37/321: {the radio frequency energy being inductively coupled to the plasma}
- H01J 37/32174: {Circuits specially adapted for controlling the RF discharge}
- H01J 37/32183: {Matching circuits}
- H01J 37/32568: {Relative arrangement or disposition of electrodes; moving means}
- H01J 2237/3321: CVD [Chemical Vapor Deposition]
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)

## Abstract

Implementations described herein generally relate to components and methods used in plasma processing, and more specifically relate to grooved surfaces for controlling RF return path lengths in plasma processing chambers and methods for forming the same. In one implementation, a backing plate for a plasma processing chamber is provided. The backing plate comprises a rectangular body. The rectangular body has a front surface, a back surface opposing the front surface, a first axis perpendicular to a center of the rectangular body and a plurality of grooves formed in the front surface. At least one groove of the plurality of grooves has a first length across the groove in a first location and a second length across the groove in a second location.

## Claims

### Claim 1

A backing plate for a plasma processing chamber, comprising:
a rectangular body having:
a front surface;
a back surface opposing the front surface; a first axis perpendicular to a center of the rectangular body; and
a plurality of circular grooves formed in the front surface, concentric to the first axis and spaced apart from each other;
a first RF return path orthogonal to the first axis and extending across the front surface of the rectangular body from the first axis across the plurality of circular grooves to a corner of the rectangular body; and
a second RF return path orthogonal to the first axis and extending across the front surface of the rectangular body from the first axis across the plurality of circular grooves to a midpoint of an edge of the rectangular body; and
wherein each groove of the plurality of circular grooves has a first groove profile defined along the first RF return path by a first depth and a first width and a second groove profile defined along the second RF return path by a second depth and the first width, wherein the second depth is greater than the first depth, and
wherein the second groove profile is larger than the first groove profile such that a first length of the front surface defined along the first RF return path across the plurality of circular grooves is equal to or substantially equal to a second length defined along the second RF return path.

### Claim 2 (depends on 1)

The backing plate of claim 1, wherein the first length defined by the first RF return path includes the first groove profile of each groove.

### Claim 3 (depends on 2)

The backing plate of claim 2, wherein the second length defined by the second RF return path includes the second groove profile of each groove.

### Claim 4 (depends on 1)

The backing plate of claim 1, wherein the plurality of circular grooves comprises from about 2 to about 20 grooves.

### Claim 5 (depends on 4)

The backing plate of claim 4, wherein the plurality of circular grooves comprise eight grooves.

### Claim 6 (depends on 1)

The backing plate of claim 1, wherein the backing plate is composed of aluminum.

### Claim 7 (depends on 1)

The backing plate of claim 1, wherein the grooves of the plurality of circular grooves are uniformly spaced with a pitch P and the pitch P is a radial distance between adjacent grooves.

### Claim 8 (depends on 1)

The backing plate of claim 1, further comprising an annular partition having a width Wp between adjacent grooves.

### Claim 9 (depends on 1)

The backing plate of claim 1, wherein each groove of the plurality of circular grooves has an inclination causing a depth of the groove to increase from the first depth to the second depth.

### Claim 10

A plasma processing chamber, comprising:
a chamber body defining a process volume; a substrate support disposed in the process volume;
a radio frequency (RF) power source operable to provide power to generate a plasma within the process volume; and
a backing plate positioned over the processing volume and comprising:
a rectangular body having:
a front surface;
a back surface opposing the front surface; a first axis perpendicular to a center of the rectangular body; and
a plurality of circular grooves formed in the front surface, concentric to the first axis and spaced apart from each other;
a first RF return path orthogonal to the first axis and extending across the front surface of the rectangular body from the first axis across the plurality of circular grooves to a corner of the rectangular body; and
a second RF return path orthogonal to the first axis and extending across the front surface of the rectangular body from the first axis across the plurality of circular grooves to a midpoint of an edge of the rectangular body; and
wherein each groove of the plurality of circular grooves has a first groove profile defined along the first RF return path by a first depth and a first width and a second groove profile defined along the second RF return path by a second depth and the first width, wherein the second depth is greater than the first depth, and
wherein the second groove profile is larger than the first groove profile such that a first length of the front surface defined along the first RF return path is equal to or substantially equal to a second length defined along the second RF return path.

### Claim 11 (depends on 10)

The plasma processing chamber of claim 10, wherein the back surface of the backing plate faces the process volume.

### Claim 12 (depends on 10)

The plasma processing chamber of claim 10, further comprising a diffuser coupled with the backing plate.

### Claim 13 (depends on 12)

The plasma processing chamber of claim 12, wherein the RF power source is coupled to the backing plate and/or the diffuser.

### Claim 14 (depends on 10)

The plasma processing chamber of claim 10, wherein the first length defined by the first RF return path includes the first groove profile of each groove.

### Claim 15 (depends on 14)

The plasma processing chamber of claim 14, wherein the second length defined by the second RF return path includes the second groove profile of each groove.

### Claim 16 (depends on 10)

The plasma processing chamber of claim 10, wherein the plurality of circular grooves comprises from about 2 to about 20 grooves.

### Claim 17 (depends on 10)

The plasma processing chamber of claim 10, wherein the backing plate is composed of aluminum.

### Claim 18 (depends on 10)

The plasma processing chamber of claim 10, wherein the grooves of the plurality of circular grooves are uniformly spaced with a pitch P and the pitch P is a radial distance between adjacent grooves.

### Claim 19 (depends on 10)

The plasma processing chamber of claim 10, further comprising an annular partition having a width Wp between adjacent grooves.

### Claim 20 (depends on 10)

The plasma processing chamber of claim 10, wherein each groove of the plurality of circular grooves has an inclination causing a depth of the groove to increase from the first depth to the second depth.