Shower plate, method for manufacturing the shower plate, plasma processing apparatus using the shower plate, plasma processing method and electronic device manufacturing method

• US 8,372,200 B2
• Filed: 06/13/2007
• Issued: 02/12/2013
• Est. Priority Date: 06/13/2006
• Status: Expired due to Fees

• Current Assignee: National University Corporation Chiba University, Tokyo Electron Limited
• Original Assignee: National University Corporation Chiba University, Tokyo Electron Limited
• Inventors: Okesaku, Masahiro, Goto, Tetsuya, Ohmi, Tadahiro, Ishibashi, Kiyotaka
• Primary Examiner(s): LUND, JEFFRIE ROBERT
• Application Number:
  US12/308,333
• Publication Number:
  US 20100230387A1
• Time in Patent Office: 2,071 Days
• Field of Search: 118/715, 156/345.33, 156/345.34
• US Class Current: 118/715
• CPC Class Codes: B05B 1/18 Roses; Shower heads with means for adding soap or the like E03C1/046; jet regulators E03C1/08
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: C23C 16/45568 Porous nozzles
• CPC Class Codes: C23C 16/511 using microwave discharges
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow

Abstract

Occurrence of a back-flow of plasma or ignition of gas for plasma excitation in a longitudinal hole portion can be prevented more completely, and a shower plate in which efficient plasma excitation is possible is provided. In shower plate 105, which is arranged in processing chamber 102 of a plasma processing apparatus and discharges gas for plasma excitation into processing chamber, porous-gas passing body 114 having a pore that communicates in the gas flow direction is fixed onto longitudinal hole 112 used as a discharging path of gas for plasma excitation. The pore diameter of a narrow path in a gas flowing path formed of a pore, which communicates to porous-gas passing body 114, is 10 μm or lower.

Claims

1. A shower plate provided in a plasma processing apparatus to discharge gas for plasma excitation for generating plasma in a processing chamber of the plasma processing apparatus, the shower plate comprising:

a plate having a plurality of longitudinal holes;

a porous-gas passing body disposed in a gas inlet side of each of the plurality of longitudinal holes, which are used as a discharging path of the gas for plasma excitation; and

a ceramic element, provided with a plurality of gas discharge holes, disposed in a gas outlet side of each of the plurality of longitudinal holes

wherein;

the porous-gas passing body having a pore that communicates with the ceramic element, in a gas flow direction, through the plurality of gas discharge holes, and

an average pore diameter of a narrow path in a gas flowing path formed by the pore which passes through the porous-gas passing body is not greater than 10 μ

m.

2. The shower plate of claim 1, wherein the porous-gas passing body is structured by an alumina based material having a dielectric loss of not greater than 1×

10<sup>−

3</sup>, an average diameter of a crystal not greater than 10 μ

m, a pore rate of 20 to 75%, an average pore diameter of not greater than 10 μ

m, and a bending strength of not less than 30 MPa.

3. The shower plate of claim 1, wherein an aperture of each of the plurality of gas discharge holes is not greater than two times of a sheath thickness of plasma formed directly under a shower plate, wherein the sheath thickness of plasma is the defined by:

D=0.606λ

_D*(2V₀/T_e)^3/4

Wherein;

V₀ is a voltage difference between plasma and a substance,

T_e is electron temperature, and

λ

_D is Debye length defined by 7.43*10³(T_e/n_e)^1/2 where n_e is an electron density of plasma.

4. The shower plate of claim 1, wherein a gas passage hole having a diameter, which is greater than an aperture of each of the plurality of gas discharge hole, is provided continuously in the gas introduction side of the porous-gas passing body.

5. The shower plate of claim 1, wherein a gas discharge hole is provided on a gas discharge side of a longitudinal hole opened in the shower plate, and chamfering processing is applied to a corner of a gas introduction side of the longitudinal hole.

6. The shower plate of claim 1, wherein an upper surface and an undersurface of the porous-gas passing body are both curving toward inside of the plasma processing apparatus in a shape of a convex curve or in a shape of a concave curve.

7. A plasma processing apparatus into which the shower plate of claim 1 is disposed.