JPH08246155A - Surface treatment equipment for work pieces - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a plasma CVD apparatus in which reaction products hardly or do not deposit on the inner surface of the side wall of a processing chamber. A plasma CVD apparatus 20, which is one of the surface treatment apparatuses of the present invention, has a plurality of linear projections 23 formed on the inner surface of a side wall 21 of a processing chamber 5, and the upper side of the side wall 21 extends from above to below. A jet nozzle 22 along the side wall
An inert gas is ejected from the inner wall of the exhaust gas, an annular exhaust port 24 is formed over substantially the entire circumference of the bottom surface near the side wall 21, and a plurality of straightening vanes 26 are arranged on the inner wall of the exhaust port.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can form an insulating film, a conductive film or the like on the surface of an object such as a semiconductor wafer or an optical disk, or can perform a surface treatment such as etching the insulating film or the conductive film. The present invention relates to an improvement of a surface treatment device for a workpiece such as a plasma CVD device, a normal pressure CVD device, a low pressure CVD, a photo CVD, a plasma etching device, a vapor deposition device, and a sputtering device.

[0002]

2. Description of the Related Art First, a conventional surface treatment apparatus for a workpiece will be described with reference to FIG. In the following description, a semiconductor wafer will be exemplified as a workpiece, and a plasma CVD apparatus will be exemplified as the surface treatment apparatus. FIG. 6 is a sectional perspective view schematically showing an existing plasma CVD apparatus.

Reference numeral 1 generally indicates a plasma CVD apparatus. The plasma CVD apparatus 1 is provided with a vacuum processing chamber 5 composed of a cylindrical side wall 2, a ceiling plate 3 and a bottom plate 4, and in the processing chamber 5, a perforated upper electrode 6 is provided above the central portion thereof.
The lower electrode 7 is disposed below the upper electrode 6 with a predetermined gap from the upper electrode 6. The upper electrode 6 is fixed to the ceiling plate 3 by a supporting device / reactive gas supply pipe (hereinafter simply referred to as “reactive gas supply pipe”) 8, and the lower electrode 7 is a supporting device 9 by the bottom plate. It is supported in a state of being floated from 4. Although not shown, a predetermined voltage is applied to the upper electrode 6 and the lower electrode 7. Further, an opening 10 is formed in the central portion of the ceiling plate 3 and is connected to a reaction gas supply source (not shown) via a pipe or the like. Furthermore, an exhaust port 11 is formed at one location on the bottom plate 4, and an exhaust pipe 12 is connected to the exhaust port 11.

In the case where a nitride film is formed on the surface of the semiconductor wafer S in the plasma CVD apparatus 1 having such a structure, the semiconductor wafer S is placed on the lower electrode 7 and the exhaust pipe 12 is used. Processing chamber 5 with a vacuum pump (not shown)
The inside is evacuated to a specified degree of vacuum, and SiH ₄ and N ₂ or SiH
The reaction gas of ₄ and NH ₃ is introduced from the opening 10 through the reaction gas supply pipe 8 into the processing chamber 5 through the innumerable pores opened in the upper electrode 6, and the upper electrode 6 and the lower electrode 7 are supplied under low pressure.
By applying a predetermined high frequency voltage in between to create a plasma excited state, a Si ₃ N ₄ film can be formed on the surface of the semiconductor wafer S.

[0005]

However, as the film forming operation is repeated, reaction products are deposited on the inner surface of the side wall 2 of the processing chamber 5 as shown by the dotted line in FIG. .
Normally, when the film forming process is performed about 30 times, the sidewall 2 has 10 times.
A reaction product having a film thickness of about μm is deposited. This is because the introduced amount of the reaction gas is small, for example, 200 cc per second, so that the flow velocity cannot be secured, and therefore the boundary layer is generated on the surface of the inner surface of the side wall 2 due to the viscosity of the reaction gas as shown in FIG. It is considered that this is because turbulent flow of the reaction gas does not occur. In order to generate turbulent flow on the inner surface of the side wall 2, it is sufficient to increase the amount of exhaust gas through the exhaust pipe 12. Then, the exhaust gas becomes turbulent at the exhaust port 11 part, causing winding and smooth exhaust. Since it becomes impossible, the flow velocity of the reaction gas cannot be increased on the inner surface of the side wall 2.

As the reaction product accumulates, it peels off from the inner surface of the side wall 2 and adheres to the semiconductor wafer S, causing a product defect. Before the reaction product is peeled off, for example, every time the film forming process is performed 30 times, the deposited reaction product is removed by dry etching or is wiped by hand with a chemical. There is. Such work of removing reaction products reduces the manufacturing efficiency of semiconductor devices. An object of the present invention is to solve such an inconvenient problem, and an object thereof is to obtain a plasma CVD apparatus in which reaction products are hard to deposit or do not deposit on the entire inner surface of the side wall 2. To do.

[0007]

Therefore, in the surface treatment apparatus of the present invention, there is provided a treatment chamber comprising a side wall having a turbulent flow generation projection formed on the inner surface thereof, and a portion near the upper portion of the side wall of the treatment chamber extending from the upper side to the lower side. A jet nozzle for jetting an inert gas along the side wall, an exhaust port formed over substantially the entire circumference of the bottom surface of the processing chamber near the side wall, and a plurality of gases arranged on the inner wall of the exhaust port. The above-mentioned problems were solved by using a current plate.

[0008]

Therefore, according to the surface treatment apparatus of the present invention, the jetted inert gas hits the turbulent flow generation projections on the inner surface of the side wall to generate a turbulent flow, and the curtain wall of the inert gas is formed on the inner surface of the side wall. Therefore, the reaction gas is blocked by the curtain wall and does not reach the inner surface of the side wall. Therefore, the reaction gas and the inert gas reaching the exhaust port reach the exhaust port, and the reaction gas and the inert gas reach the exhaust port. Exhaust can be performed smoothly without causing turbulent flow near the inlet of the exhaust port in the presence.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a plasma CVD apparatus which is one of the surface treatment apparatuses of the present invention will be described with reference to FIGS. 1 is a sectional perspective view schematically showing the plasma CVD apparatus of the present invention, and FIG. 2 is the plasma C shown in FIG.
FIG. 4 is a partially enlarged sectional perspective view of the vicinity of an inert gas injection port of the VD apparatus, FIG. 3 is a partially enlarged sectional perspective view of the side wall of the plasma CVD apparatus shown in FIG. 1, and FIG. FIG. 3 is a partial sectional perspective view of an exhaust port of the plasma CVD apparatus shown in FIG. In the following description, the same components as those of the conventional plasma CVD apparatus 1 shown in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted.

The plasma CVD apparatus 20 of the present invention is provided with a vacuum processing chamber 5 consisting of a cylindrical side wall 21, a ceiling plate 3 and a bottom plate 4, and the inside of the processing chamber 5 is located above the central portion thereof. The fact that the upper electrode 6 of the hole and the lower electrode 7 below the upper electrode 6 are spaced apart from the upper electrode 6 by a predetermined distance means that the conventional plasma CVD apparatus 1
Is the same as The upper electrode 6 is fixed to the ceiling plate 3 by a reaction gas supply pipe 8, and the lower electrode 7 is supported by a supporting device 9 in a state of being floated from the bottom plate 4. Although not shown, a predetermined high frequency voltage is applied to 6 and the lower electrode 7, and
An opening 10 is formed at the center of the ceiling plate 3,
The same applies to connection to a reaction gas supply source (not shown) via a pipe or the like.

In the plasma CVD apparatus 20 of the present invention, as shown in FIG. 2, an annular injection nozzle 22 is provided over the entire circumference of the corner between the ceiling plate 3 and the side wall 21. As shown in FIG. 3, from the vicinity of the upper end of the side wall 21 to the vicinity of the lower end thereof, a plurality of linear projections 23 having a triangular cross section having an annular shape, which are turbulent flow generation projections, are formed at predetermined intervals. Furthermore, in this plasma CVD apparatus 20, as shown in FIG. 4, an annular exhaust port 24 is formed in the bottom plate 4 substantially opposite to the injection nozzle 22, and the annular exhaust port 24 is formed in the annular exhaust port 24. An annular exhaust pipe 25 is formed. This annular exhaust pipe 25
A plurality of straightening vanes 26 are provided alternately on both inner walls in parallel with each other. The bottom plate 4 divided by the annular exhaust port 24 is connected by a plurality of beams 27.

The plasma CVD apparatus 20 having such a configuration
When a nitride film is formed on the surface of the semiconductor wafer S, the semiconductor wafer S is placed on the lower electrode 7,
The processing chamber 5 is evacuated to a predetermined degree of vacuum from the annular exhaust port 24 by a vacuum pump (not shown), and reaction gas of SiH ₄ and N ₂ or SiH ₄ and NH ₃ is passed through the reaction gas supply pipe 8 from the opening 10. Introducing into the processing chamber 5 through the innumerable pores opened in the upper electrode 6, and applying a predetermined high-frequency voltage between the upper electrode 6 and the lower electrode 7 under a low pressure to create a plasma excited state, Si on the surface of the semiconductor wafer S
_{Although a 3} N ₄ film can be formed, as shown in FIG. 2, an inert gas such as nitrogen gas N ₂ is continuously ejected from the ejection nozzle 22 during such film formation.

The continuously ejected nitrogen gas N ₂ hits a plurality of linear projections 23 formed on the side wall 21, and the nitrogen gas N ₂ shown in FIG.
As shown in, the turbulent flow W is generated from the upper side to the lower side on the inner surface of the side wall 21, and the state where the curtain wall of the nitrogen gas N ₂ is formed. Therefore, the reaction product, which tends to reach the inner surface of the side wall 21 due to diffusion or the like, is blocked by the curtain wall and cannot reach the inner surface of the side wall 21, and as shown in FIG. The reaction product and the nitrogen gas N ₂ flowing toward the annular exhaust port 24 are accelerated in the processing chamber 5 due to the presence of the plurality of flow straightening plates 26, and are disturbed near the inlet of the annular exhaust port 24. It is possible to smoothly exhaust the gas from the processing chamber 5 through the annular exhaust pipe 25 without causing a flow. When the inside of the processing chamber 5 is evacuated, a turbulent flow is usually generated at the start of the vacuum to cause dust to wind up. However, since the rectifying plate 26 is provided, the processing at the start of the vacuum is performed. Turbulence does not occur in the chamber 5, and therefore also plays a role of preventing the phenomenon of dust winding.

[0014]

As described above, according to the plasma CVD apparatus of the present invention, as shown by the solid line in FIG. 5, almost no reaction product is deposited on the inner surface of the side wall of the processing chamber, Further, since the annular exhaust port and the straightening plate are provided inside the exhaust port, it is possible to prevent dust winding up due to turbulent flow that tends to occur when the vacuum in the processing chamber is started, and reduce product defects.

[Brief description of drawings]

FIG. 1 is a sectional perspective view schematically showing a plasma CVD apparatus of the present invention.

FIG. 2 is a partially enlarged sectional perspective view of the vicinity of an inert gas injection port of the plasma CVD apparatus shown in FIG.

3 is a partially enlarged sectional perspective view of a side wall of the plasma CVD apparatus shown in FIG.

4 is a partial cross-sectional perspective view of an exhaust port of the plasma CVD apparatus shown in FIG.

FIG. 5 is a graph showing the relationship between the number of film forming processes and the film thickness of the reaction product deposited on the inner surface of the side wall.

FIG. 6 is a sectional perspective view schematically showing a conventional plasma CVD apparatus.

7 is a partially enlarged sectional perspective view of a side wall of the plasma CVD apparatus of FIG.

[Explanation of symbols]

 5 Processing Chamber 6 Upper Electrode 7 Lower Electrode 20 Plasma CVD Device 21 Side Wall 22 Injection Nozzle 23 Linear Protrusion 24 Annular Exhaust Port 25 Annular Exhaust Pipe 26 Straightening Plate 27 Beam

Claims (1)

[Claims] 1. A processing chamber including a sidewall having a turbulent flow generation projection formed on an inner surface thereof, and an injection nozzle for ejecting an inert gas along the sidewall from above to near the upper portion of the sidewall of the processing chamber. An exhaust port formed over substantially the entire circumference of the bottom surface of the processing chamber near the side wall, and a plurality of gas rectifying plates disposed on the inner wall of the exhaust port. Surface treatment equipment for workpieces.