METHOD FOR PROVIDING UNIFORM DISTRIBUTION OF PLASMA DENSITY IN A PLASMA TREATMENT APPARATUS

• US 20150214013A1
• Filed: 01/25/2014
• Published: 07/30/2015
• Est. Priority Date: 01/25/2014
• Status: Active Grant

• Current Assignee: Yuri Glukhoy
• Original Assignee: Yuri Glukhoy
• Inventors: GLUKHOY, Yuri
• Granted Patent: US 9,275,840 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B05D 7/22 to internal surfaces, e.g. of tubes
• CPC Class Codes: C23C 14/083 of refractory metals or yttrium
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: H01J 2237/0213 Avoiding deleterious effects due to interactions between particles and tube elements
• CPC Class Codes: H01J 2237/04 Means for controlling the discharge
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow
• CPC Class Codes: H01J 37/32477 characterised by the means for protecting vessels or internal parts, e.g. coatings
• CPC Class Codes: H01J 37/32807 Construction (includes replacing parts of the apparatus)
• CPC Class Codes: Y10T 29/4998 Combined manufacture including applying or shaping of fluent material

Abstract

Proposed is a method for providing uniform distribution of plasma density in a CCP plasma processing apparatus. According to the method the through gas holes of the showerhead of used in the plasma processing chamber of the apparatus are provided with conical nozzles formed on the side of the gas holes that face the gas reservoir of the cooler plate. The cone angle θ of the nozzles decreases in the direction from the peripheral portion to the central area of the showerhead in the range from 120° to 0°. Since the conical nozzles increase the gas gap between the showerhead and the cooler plate, more favorable conditions are created for electric breakdown. In order to protect the surfaces of the conical nozzles and gas holes from deterioration by hollow cathode discharge, these surface are coated by a protective coating resistant to electrical breakdown and chemical corrosion.

Claims

1. A method for providing uniform distribution of plasma density in a CCP plasma processing apparatus, the method comprising the steps of:

providing a showerhead-cooler system of a semiconductor-processing chamber of the CCP plasma processing apparatus intended for plasma processing of objects, the system comprising a showerhead having a plurality of through gas holes and a gas-feeding cooler plate that is connected to an RF power supply, has an electric contact with the showerhead and forms with the showerhead a gas accumulation reservoir, one ends of the gas holes being connected to the gas accumulation reservoir, and the other ends of the gas holes being connected to semiconductor-processing chamber, the gas-feeding cooler plate being connected to a source of a working gas and has a plurality of through gas feeding passages that communicate with the gas accumulating reservoir, the shower head having a central area and a peripheral portion;

forming on said one ends of at least some of the through gas holes conical nozzles with a cone angle θ

that decreases in the direction from the peripheral portion to the central area of the showerhead in the range from;

120°

to 0°

; and

coating the surfaces of the conical nozzles and at least a part of the walls of the gas holes in the area adjacent to the conical nozzles with a protective coating resistant to electrical breakdown and chemical corrosion.

2. The method of claim 1, wherein the protective coating is an yttrium oxide coating.

3. The method of claim 2, wherein the object is a semiconductor wafer.

4. The method of to claim 3, wherein the wafer has a diameter of 450 mm.

5. The method of claim 1, further providing the following relationship between the cone angle θ

of the conical nozzle of through gas holes that have the conical nozzles and a radial distance R of the through gas holes from the showerhead center;

(1+bR)=[1−

1/{1−

[(2l_H tan θ

)/d_H]}⁴]<sup>−

1/2</sup>  

 

(1)

where d_H is a diameter of the through gas hole, l_H is a length of the through gas hole, and bis a coefficient that depends on the parameters of the plasma process.

6. The method of claim 2, further providing the following relationship between the cone angle θ

of the conical nozzle of through gas holes that have the conical nozzles and a radial distance R of the through gas holes from the showerhead center,

(1+bR)=[1−

1/{1−

[(2l_H tan θ

)/d_H]}⁴]<sup>−

1/2</sup>  

 

(1)

where d_H is a diameter of the through gas hole, l_H is a length of the through gas hole, and bis a coefficient that depends on the parameters of the plasma process.

7. The method of claim 3, further providing the following relationship between the cone angle θ

of the conical nozzle of through gas holes that have the conical nozzles and a radial distance R of the through gas holes from the showerhead center;

(1+bR)=[1−

1/{1−

[(2l_H tan θ

)/d_H]}⁴]<sup>−

1/2</sup>  

 

(1)

where d_H is a diameter of the through gas hole, l_H is a length of the through gas hole, and bis a coefficient that depends on the parameters of the plasma process.

8. The method of claim 4, further providing the following relationship between the cone angle θ

of the conical nozzle of through gas holes that have the conical nozzles and a radial distance R of the through gas holes from the showerhead center;

(1+bR)=[1−

1/{1−

[(2l_H tan θ

)/d_H]}⁴]<sup>−

1/2</sup>  

 

(1)

where d_H is a diameter of the through gas hole, l_H is a length of the through gas hole, and bis a coefficient that depends on the parameters of the plasma process.