Plasma processing apparatus with a dielectric plate having a thickness based on a wavelength of a microwave introduced into a process chamber through the dielectric plate

• US 20010050059A1
• Filed: 03/23/2001
• Published: 12/13/2001
• Est. Priority Date: 03/24/2000
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Hongo, Toshiaki, Osawa, Tetsu
• Granted Patent: US 6,372,084 B2
• Time in Patent Office: Days
• US Class Current: 118/723.0MW
• CPC Class Codes: C23C 16/511 using microwave discharges
• CPC Class Codes: H01J 37/32192 Microwave generated discharge H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence

Abstract

A plasma processing apparatus applies a high-quality process to an object to be processed by preventing impurities from being generated due to a microwave transmitting through a dielectric plate. The dielectric plate is provided between a process chamber of a plasma processing apparatus and a slot electrode guiding a microwave used for a plasma process. A thickness H of the dielectric plate has a predetermined relationship with a wavelength λ of the microwave in the dielectric plate so that an amount of isolation of the dielectric plate due to transmission of the microwave is minimized. The wavelength λ is represented by λ=λ₀n, where λ₀ is a wavelength of the microwave in a vacuum and n is a wavelength reducing rate of the dielectric plate represented by n=1/(∈_t)^½, where ∈_t is a specific dielectric rate of the dielectric plate in a vacuum.

Claims

1. A dielectric plate adapted to be provided between a process chamber of a plasma processing apparatus and a slot electrode guiding a microwave used for a plasma process,

wherein a thickness H of said dielectric plate has a predetermined relationship with a wavelength λ

of the microwave in said dielectric plate so that an amount of isolation of said dielectric plate due to transmission of the microwave is minimized, the wavelength λ

being represented by λ

=λ

₀n, where λ

₀ is a wavelength of the microwave in a vacuum and n is a wavelength reducing rate of said dielectric plate represented by n=1/(∈

_t)^½

, where ∈

_t is a specific dielectric rate of said dielectric plate in a vacuum.

2. The dielectric plate as claimed in

claim 1

, wherein the predetermined relationship between the thickness H and the wavelength λ

of said dielectric plate is represented by 0.5λ

<

H<

0.75λ

.

3. The dielectric plate as claimed in

claim 2

, wherein the thickness H of said dielectric plate satisfies a relationship represented by 0.6λ

≦

H≦

0.7λ

.

4. The dielectric plate as claimed in

claim 1

, wherein the predetermined relationship between the thickness H and the wavelength λ

of said dielectric plate is represented by 0.3λ

<

H<

0.4λ

.

5. The dielectric plate as claimed in

claim 1

, wherein the predetermined relationship between the thickness H and the wavelength λ

of said dielectric plate is represented by one of the relationships (0.1+0.5N)λ

≦

H≦

(0.2+0.5N)λ and

(0.3+0.5N)λ

≦

H≦

(0.4+0.5N)λ

, where N is an integer.

6. A plasma processing apparatus comprising:

a process chamber in which a plasma process is applied to an object to be processed;

a slot electrode having a plurality of slits guiding a microwave introduced into said process chamber so as to generate plasma in said process chamber; and

a dielectric plate provided between said slot electrode and said process chamber, wherein a thickness H of said dielectric plate has a predetermined relationship with a wavelength λ

of the microwave in said dielectric plate so that an amount of isolation of said dielectric plate due to transmission of the microwave is minimized, the wavelength λ

being represented by λ

=λ

₀n, where λ

₀ is a wavelength of the microwave in a vacuum and n is a wavelength reducing rate of said dielectric plate represented by n=1/(∈

_t)^½

, where ∈

_t is a specific dielectric rate of said dielectric plate in a vacuum.

7. The plasma processing apparatus as claimed in

claim 6

, wherein the predetermined relationship between the thickness H and the wavelength λ

of said dielectric plate is represented by 0.5λ

<

H<

0.75λ

.

8. The plasma processing apparatus as claimed in

claim 7

, wherein the thickness H of said dielectric plate satisfies a relationship represented by 0.6λ

≦

H≦

0.7λ

.

9. The plasma processing apparatus as claimed in

claim 6

, wherein the predetermined relationship between the thickness H and the wavelength λ

of said dielectric plate is represented by 0.3λ

<

H<

0.4λ

.

10. The plasma processing apparatus as claimed in

claim 6

, wherein the predetermined relationship between the thickness H and the wavelength λ

of said dielectric plate is represented by one of the relationships (0.1+0.5N)λ

≦

H≦

(0.2+0.5N)λ and

(0.3+0.5N)λ

≦

H≦

(0.4+0.5N)λ

, where N is an integer.