JPH1072669A - Plasma treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma treating device capable of executing a uniform plasma treatment by improving the structure of a discharge system for waste gases. SOLUTION: Inside wall members 122 are arranged apart a prescribed spacing from the side walls 104a of a treating vessel 104 and a treating chamber 102 is formed on the inner side thereof. The inside walls of the treating chamber 102 are composed as tapered surfaces expanding upward and outward by the hypotenuses 122b of the inside wall members 122, by which a part of the discharge system is constituted. The ceiling section 104b of the treating vessel 104 is provided with axisymmetrical or four connected overhanging members 123. The outer flanks 125b of these overhanging members 123 are so constituted as to be approximately parallel with the tapered inside wall surfaces 122b of the inside wall members 122. Then, the waste gases in the treating chamber 102 are made to flow efficiently while the gases are diffused along the tapered surfaces of the inside walls and, therefore, the obtaining of the more uniform density of the plasma is accelerated and the desired uniform plasma treatment is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus, and more particularly to a structure of an exhaust gas (processing gas) exhaust port.

[0002]

2. Description of the Related Art A typical ECR type plasma CVD apparatus 10 conventionally known will be described with reference to FIG. A plasma generation chamber 14 is provided substantially at the center of the upper part of the processing chamber 12. The plasma generation chamber 14 and the processing chamber 12 are in communication with each other, and are configured such that plasma generated in the plasma generation chamber 14 can be introduced into the processing chamber 12 as described later. Further, a coil 16 that generates a magnetic field, which is one of the ECR conditions, is provided in the outer peripheral wall of the plasma generation chamber 14.

At a substantially central portion of the upper portion of the plasma generation chamber 14, a predetermined microwave oscillated from a microwave source (not shown) is applied through a dielectric wall 18 made of a dielectric material such as quartz. Waveguide 2 for introduction into
0 is connected.

A first gas supply pipe 22 is connected to the upper wall of the plasma generation chamber 14 to generate a predetermined plasma ignition reaction gas (A), for example, Ar gas from a gas supply source (not shown). It is configured so that it can be introduced into the chamber 14 from above.

A second gas supply pipe 24 is connected to a lower side wall of the plasma generation chamber 14, and a predetermined film forming reaction gas (B), for example, Si, is supplied from a gas supply source (not shown).
It is configured such that H ₄ / O ₂ gas can be introduced into the plasma generation chamber 14 from below.

At the time of plasma processing, when a predetermined microwave is introduced into the plasma generation chamber 14 via the waveguide 20 and the dielectric wall 18 and Ar gas is introduced from the first gas supply pipe 22, An ECR plasma is generated by a magnetic field generated by the coil 16. Furthermore, the EC
By the R plasma, the SiH ₄ / O ₂ gas for film formation introduced from the second gas supply pipe 24 is dissociated, activated, turned into plasma, and becomes reactive plasma.

The reactive plasma is supplied to the plasma generation chamber 1
After performing a predetermined plasma process, for example, a film forming process, on the processing target W placed on the mounting table 26 from the inside of the processing chamber 12 from the inside, The gas is exhausted from the connected exhaust pipe 28 by the operation of a vacuuming means (not shown).

[0008]

In the above-described conventional apparatus, a processing gas, that is, a so-called exhaust gas after a plasma processing, for example, a film forming process, is performed on the object to be processed, and the processing gas below the object is processed. Since the gas is exhausted from the back side of the body, the processing gas or the like flows efficiently at the peripheral edge of the processing surface of the processing object. Has become.

That is, the stagnation causes the plasma density on the surface of the object to be non-uniform. For example, when a film forming process is performed on the object to be processed, the generated film becomes thick at a substantially central portion of the object to be processed. In addition, there is a problem that the peripheral portion of the workpiece becomes thin and the in-plane thickness of the workpiece cannot be uniform, and exhaust gas remains in a substantially central portion of the workpiece to form a reaction by-product on the surface of the workpiece. There is a problem that the object is easily attached and the yield is reduced. In recent years, the object to be processed has been super-integrated, ultra-fine, and large-sized, and such a problem has become more remarkable. In addition, as the aspect ratio with respect to the grooves and holes in the semiconductor fine structure increases, the improvement in step coverage is required, and for this reason, better airflow control is expected. I have.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of a conventional plasma processing apparatus, and improves the efficiency of exhaust gas flow by improving the structure of an exhaust path for exhaust gas from a processing chamber. It is an object of the present invention to provide a new and improved plasma processing apparatus capable of achieving uniform plasma processing and further improving exhaust characteristics, thereby achieving uniform plasma processing and good step coverage.

[0011]

According to a first aspect of the present invention, a plasma generating chamber and a plasma processing chamber are provided, and plasma excited in the plasma generating chamber is introduced into the plasma processing chamber. By doing so, in a plasma processing apparatus that performs predetermined plasma processing on a target object placed in the plasma processing chamber, at least a part of the inner wall of the processing chamber is outwardly directed upward from the target object. It is characterized in that it is configured as a tapered surface that spreads out to form a part of the exhaust path, and an exhaust system having one or more exhaust ports is connected above the tapered surface.

According to this configuration, the exhaust gas generated in the processing chamber efficiently flows while diffusing along the tapered surface of the processing chamber wall. So-called stagnation does not occur. Therefore, uniformization of the plasma density between the substantially central portion of the object to be processed and the peripheral portion thereof is promoted, and the in-plane uniformity of the plasma processing can be achieved. Further, it is possible to avoid the adhesion of the reaction by-product to the substantially central portion of the object to be processed, and to improve the yield. In addition, the improvement in the exhaust efficiency makes it possible to uniformly and efficiently introduce the plasma onto the object to be processed, thereby improving the throughput. Further, the direction of incidence of the film-forming species on the object to be processed becomes closer to vertical, and good step coverage can be expected.

Further, the invention according to claim 2 is characterized in that a projecting member having a surface substantially parallel to the tapered surface is attached to a ceiling surface of the processing chamber. According to this configuration, the plasma introduced into the processing chamber;
Exhaust gas exhausted from the processing chamber to the exhaust path is optimally separated, and a uniform and efficient flow is formed in the processing chamber, whereby uniform plasma processing can be performed.

Further, according to the third aspect of the present invention,
Since a flow straightening plate for equalizing the flow of the exhaust gas is provided in the exhaust path, the flow of the exhaust gas in the processing chamber is equalized, the exhaust gas is efficiently exhausted to the exhaust path, and the exhaust efficiency is further improved.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
The plasma processing apparatus according to the present invention is an ECR type plasma C
An embodiment applied to a VD device will be described in detail. In the following description, components having substantially the same functions and configurations will be denoted by the same reference numerals, and redundant description will be omitted.

First, referring to FIG. 1, the structure of a processing container 104 of a CVD apparatus 100 according to the present embodiment will be schematically described. The processing container 104 is made of a conductive material, for example, whose surface is anodized. The processing chamber 102, which has a substantially cylindrical shape made of aluminum and performs a predetermined plasma process on an object to be processed such as a wafer W mounted on a mounting table 130, is provided with a side wall 1 of the processing container 104.
Inner wall member 122 arranged at a predetermined interval from the inner wall member 122
Is formed inside.

The inner wall member 122 of the processing vessel 104 has a cross section including the central axis in the shape of a right triangle in which the outer side 122a and the bottom side form a right angle, and the oblique side 122b faces the processing chamber 102 side. That is, the inner wall of the processing chamber 102 is formed as a tapered surface that extends upward and outward by the oblique side 122b, and forms a part of an exhaust path as described later. The top 122c of the inner wall member 122 does not reach the ceiling 104b of the processing container 104, and a gap is formed at a predetermined interval between the inner wall member 122 and the ceiling 104b of the processing container 104. The gap communicates with an exhaust path formed between the outer surface 122a of the inner wall member 122 and the side wall 104a of the processing container 104, as described later, and is configured to form a part of the exhaust path. I have.

Further, the ceiling 104b of the processing vessel 104
Has an axisymmetric or four connected overhangs 12
3 are provided. In the device according to the present embodiment,
Four exhaust ports 126 are provided at the four corners of the processing container 104, and the exhaust path from the upper gap of the processing chamber 102 to these four exhaust ports 126 is axially symmetric or has four connected overhang members 123, Are partitioned by the oblique side 122b of the internal member 122 which is substantially parallel to. Since the exhaust path communicates with the upper gap of the processing chamber 102 having a relatively wide width and the exhaust port 126 having a relatively narrow width, the exhaust path is configured as a substantially fan-shaped path as shown in FIG. Have been.

The projecting member 123 has a triangular cross section including the central axis, and has an inner surface 125a.
Functions as a guide surface for guiding the plasma flow introduced from the plasma generation chamber 106 to the surface to be processed of the wafer W as described later. The outer surface 125b is configured to be substantially parallel to the tapered inner wall surface 122b of the inner wall member 122, and functions as a part of the exhaust path.

With this configuration, the exhaust from the processing chamber 102 is supplied to the inner wall surface 122 of the inner wall member 122 as described later.
b and the outer surface 125 b of the overhang member 123 to reach the upper space of the processing chamber 102, which then communicates with the four exhaust ports 126.
The air is diverted into four exhaust paths formed between the inner wall member 04a and the outer side surface 122a of the inner wall member 122, and is exhausted from each exhaust port 126 by exhaust means (not shown). As described above, according to the apparatus according to the present embodiment, since the gas is exhausted from above the wafer W and the inside of the processing chamber 102 can be exhausted through the plurality of exhaust paths, a large amount of exhaust is efficiently performed. The present invention can be suitably applied to a process in which good step coverage is required, as required.

In the apparatus according to the present embodiment, as shown in FIG. 3, a plurality of rectifying plates 128 are provided in each of the four exhaust paths, and the exhaust is efficiently introduced into the exhaust ports 126. It is configured to be able to.

Returning to FIG. 1, an airtight, substantially cylindrical plasma generating chamber 106 made of a dielectric material, for example, quartz is provided substantially at the center of the upper portion of the processing chamber 102.
The plasma generation chamber 106 and the processing chamber 102 are in communication with each other, and are configured so that reactive plasma generated in the plasma generation chamber 106 can be introduced into the processing chamber 102 as described later. I have. Plasma generation chamber 10
In the plasma generation chamber 106, the ECR
Coil 10 for generating a magnetic field for generating plasma
8 is provided in a substantially annular shape.

In the approximate center of the upper part of the plasma generation chamber 106,
Microwave oscillating means provided in a microwave oscillation chamber (not shown), for example, a predetermined microwave oscillated from a magnetron, for example, a microwave of 2.45 GHz, is provided via a dielectric wall 110 made of a dielectric material, for example, quartz. , A waveguide 112 for introduction into the plasma generation chamber 106 is connected.

Further, a first gas supply pipe 114 and a second gas supply pipe 116 are connected to the upper wall portion of the plasma generation chamber 106, respectively. A gas supply source is connected to each of the first gas supply pipe 114 and the second gas supply pipe 116 via a valve, a mass flow controller, and the like (not shown).

With this configuration, the first gas supply pipe 114
A predetermined plasma ignition reaction gas (A), for example, Ar
The gas and a predetermined reaction gas (B) for film formation, for example, a SiH ₄ / O ₂ gas are introduced from the upper part of the plasma generation chamber 106 from the second gas supply pipe 116. Of course, the connection position of the first gas supply pipe 114 and the second gas supply pipe 116 is not limited to the upper wall portion of the plasma generation chamber 106, and can be connected to an arbitrary location such as the side wall of the plasma generation chamber 106. .

During the plasma processing, the plasma generating chamber 10
6, the first gas supply path 114 and the second gas supply path 1
16, a predetermined plasma ignition reaction gas (A),
When a predetermined reaction gas for film formation (B) is introduced and a predetermined microwave energy is introduced, EC
The R condition is set, and so-called ECR plasma is excited.

Further, in the CVD apparatus according to the present embodiment, a third gas supply member 118 is provided in a plasma introduction path connecting the plasma generation chamber 106 and the processing chamber 102. As shown in detail in FIG. 2, the third gas supply member 118 is formed by, for example, three gas introduction pipes 120 made of a substantially tubular plasma-resistant material, for example, quartz, which are arranged at substantially equal intervals of, for example, 120 °. Supported. The lower surface of the third gas supply member 118 (the surface facing the wafer W) is provided with a plasma density adjusting gas (neutral film forming gas).
Is provided.

The plasma excited in the plasma generation chamber 106 by the above-described structure is supplied to the third gas supply member 118.
Is introduced into the processing chamber 102 through the outer peripheral edge portion of the third gas supply member 118. At this time, the plasma density adjusting gas ejected from the gas ejection port 118a formed on the lower surface of the third gas supply member 118 , The plasma density is made uniform. As a gas for adjusting the plasma density supplied from the third gas supply member 118 into the processing chamber 102, a first gas supply pipe 114 is provided in the plasma generation chamber 106.
Gas (A), for example, Ar gas introduced via the second gas supply pipe 116 into the plasma generation chamber 102 via the second gas supply pipe 116, for example, SiH ₄ / O ₂ gas can be used. In addition, regarding the structure of the third gas supply member 118 for adjusting the plasma density, a patent application filed on the same date and filed by the same applicant as the present patent application (reference number: TLP950)
78 "Plasma processing apparatus"), the detailed description thereof will be omitted.

As described above, the mounting table 1 in the processing chamber 102 is generated by the plasma introduced into the processing chamber 102.
A plasma process such as a film forming process is performed on the wafer W mounted on the wafer 30. In the apparatus according to the present embodiment, the mounting table 130 is installed in the translation chamber 133. Further, a drive mechanism 138 including a translation drive motor M158 and a rotation drive motor M152 is provided below the processing chamber 102, and the mounting table 130 is rotated and translated in accordance with a control signal from the controller 154. It is possible to exercise. As described above, according to the apparatus according to the present embodiment, the wafer W mounted on the mounting table 130 is rotated and translated to eliminate unevenness in the film forming process, A uniform film forming process can be performed. Further, in the apparatus according to the present embodiment, the translation chamber 133 in which the mounting table 130 is installed communicates with the exhaust port 126, and exhaust is performed via the same exhaust system as the exhaust system of the processing chamber 102. 137 in the figure is
It is a punching plate for rectifying exhaust gas from the translation chamber 133.

The detailed structure of the drive mechanism 138 is described in detail in the specification attached to the patent application filed on the same date as the present patent application (reference number: TYL96002 “Plasma processing apparatus”). Since it is described, its detailed description will be omitted.

Next, the CVD according to the present embodiment will be described.
A case in which a silicon oxide film is formed on a surface to be processed of a semiconductor wafer W using an apparatus will be described.

First, the wafer W is transported by transport means (not shown).
Is mounted on the mounting table 130 according to the present embodiment, and the wafer W is held by a mechanical clamp (not shown). Then, the translation drive motor M158 and the rotation drive motor M1
52 is driven under a predetermined control, and the driving mechanism 138 is
A predetermined translational motion (the direction of arrow X in FIG. 1) and a predetermined rotational motion (the direction of arrow θ in FIG. 1) are performed, and the translational motion and the rotary motion are substantially respectively performed on the mounting table 130 in the translation chamber 133. Be conveyed identically. As a result, the wafer W on the mounting table 130 performs a predetermined translational motion and a rotational motion.

On the other hand, a plasma ignition gas (A), for example, Ar gas is supplied from a gas supply source (not shown) through a mass flow controller, a valve, and a first gas supply pipe 114 into the plasma generation chamber 106. Is introduced, and a film forming reaction gas (B), for example, a SiH ₄ / O ₂ gas is similarly introduced through the second gas supply pipe 116.

Further, a plasma density adjusting gas, for example, a SiH ₄ / O ₂ gas is introduced into the processing chamber 102 from the gas outlet 118 a of the third gas supply member 118. on the other hand,
The inside of the airtight processing chamber 102 is formed by the operation of a vacuuming unit (not shown) connected via an exhaust system formed above the processing chamber 102 along the inner tapered surface of the inner wall member 122 of the processing container 104. A predetermined reduced pressure atmosphere, for example, 0.1 to
It is maintained at 1 mTorr.

Then, a predetermined microwave oscillated from a microwave oscillation chamber (not shown) is introduced into the plasma generation chamber 106 in which a predetermined magnetic field is generated by a coil 108 provided on a peripheral portion of the outer wall of the plasma generation chamber 106. For example, when a microwave of 2.45 GHz is introduced through the waveguide 112 and the dielectric wall 110, the plasma generation chamber 106
The ECR plasma is excited by acting on the Ar gas introduced therein.

This plasma is further supplied to the plasma generation chamber 1
Reacts with SiH ₄ / O ₂ gas are introduced into the 06, the SiH ₄ / O ₂ gas dissociation, is plasma activated, reactive plasma is generated. The reactive plasma is the third
The gas is introduced into the processing chamber 102 while passing through the outer peripheral edge of the gas supply member 118, and the SiH ₄ / O ₂ gas is introduced into the processing chamber 102 from the gas ejection port 118 a of the third gas supply member 118. .

With this configuration, the SiH ₄ / O ₂ gas is introduced substantially near the center of the diffusion region of the reactive plasma, whereby the rotation center axis of the mounting table 130 in which the density of the reactive plasma is relatively high conventionally. A uniform film forming process, that is, a silicon oxide film having a uniform film thickness can be formed by reducing the film forming speed of the nearby wafer W.

The processing chamber 102 is formed by plasma processing.
As will be described later, the exhaust gas generated in the inner wall surface 122b of the inner wall member 122 and the outer surface 125b of the overhanging member 123
And reaches the upper space of the processing chamber 102, which then communicates with the four exhaust ports 126, the side wall 104 a of the processing container 104 and the outer surface 122 of the inner wall member 122.
The air is diverted into four exhaust paths formed between the exhaust ports a and e and exhausted from exhaust ports 126 by exhaust means (not shown). Further, in each of four exhaust passages formed between the side wall 104a of the processing container 104 and the outer side surface 122a of the inner wall member 122, a plurality of rectifying plates 128 are provided, respectively. It can be introduced into the mouth 126.

As described above, according to the present embodiment, the exhaust gas after the film forming process can be efficiently exhausted, so that the reactive plasma can be uniformly and efficiently applied to the wafer W. Introduced, the scattering due to the collision of the film-forming particles with other molecules is reduced, so that a uniform film-forming process can be performed without unevenness of the film-forming process and adhesion of reaction products, etc., and the processing speed is improved. In addition, the step coverage is improved.

Although the preferred embodiment of the present invention has been described with reference to the accompanying drawings, the present invention is not limited to such a configuration. Within the scope of the technical idea described in the claims, those skilled in the art can come up with various modified examples and modified examples, and these modified examples and modified examples are also within the technical scope of the present invention. It is understood that it belongs to.

For example, in the apparatus shown in FIG.
Although the inner wall member 122 is provided inside the inner wall 04 and the inner wall surface of the inner wall member 122 is formed to have a tapered surface that extends outwardly upward, the present invention is not limited to such a structure. For example, as shown in FIG. 4, the side wall 104 a ′ of the processing container 104 ′ itself is configured as a tapered surface that spreads outward upward, and the top and the ceiling 104 of the side wall 104 a ′ of the processing container 104 ′ are formed.
It is also possible to adopt a configuration in which a gap for exhaust is formed between the gap b ′ and the exhaust port 126 ′. In the figure, reference numeral 128 'denotes a rectifying fin disposed in the exhaust path, and 202 denotes a translation chamber 133 and the exhaust port 12;
6 ′, and is an exhaust path that communicates with 137 and 204.
Is a punching plate for rectifying the exhaust flow in the exhaust path 202.

Further, unlike the apparatus shown in FIG.
As shown in FIG. 5, in the configuration in which the exhaust port 126 ′ communicates directly with the upper part of the processing chamber 102, the exhaust port 126 ′ can be provided closer to the processing container 104, as shown in FIG. In the apparatus shown in FIG. 5, the periphery of the upper portion of the processing chamber 102 is divided into four parts at substantially equal intervals, and the four exhaust ports 127 and the exhaust ports 126 ′ over substantially the entire circumference of the processing chamber 102 are communicated to exhaust air. Although the configuration is shown, as shown in FIG. 6, a plurality of exhaust ports 127 having a narrower connection area are provided in the upper part of the processing chamber
It is also possible to adopt a configuration in which the air is exhausted while communicating with 26 ″.

In the apparatus shown in FIG. 1, the inside of the processing chamber 102 is evacuated through four exhaust paths. However, the present invention is not limited to such an example, and an arbitrary number of exhaust paths may be provided. It can be connected to the upper part of the processing chamber 102.
For example, the apparatus shown in FIGS. 7 and 8 employs a configuration in which two exhaust paths 129a and 129b or 129a 'and 129b' communicate with an upper space of the processing chamber 102 to exhaust air. In the apparatus shown in FIG. 8, in order to further increase the exhaust efficiency, a large-capacity buffer space 1 is provided in the exhaust path.
31a and 131b are provided.

[0044]

As described above, the plasma processing apparatus having the exhaust path according to the present invention performs the predetermined plasma processing on the workpiece, and thus, on the workpiece, particularly at the substantially central portion thereof. In this case, the processing gas and the like flow uniformly and efficiently, so that the so-called stagnation which has conventionally occurred does not occur. Therefore, for example, when a film formation process is performed on an object to be processed, as in the related art, the generated film becomes thicker at a substantially central portion of the object to be processed and becomes thinner at a peripheral portion of the object to be processed. Non-uniformity of the treatment and the fact that the exhaust gas remains at the substantially central portion of the object to be treated and that the reaction product adheres to the surface to be treated of the object to be treated do not occur. Further, by improving the exhaust efficiency, the processing gas can be uniformly and efficiently introduced into the object to be processed in a proper direction, so that the processing speed and the step coverage can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a plasma processing apparatus to which the present invention can be applied.

FIG. 2 is a schematic front view of a third gas supply member of the plasma processing apparatus shown in FIG. 1, taken along line AA.

FIG. 3 is a schematic cross-sectional view showing a flow straightening plate and a flow of exhaust gas in an exhaust path in the plasma processing apparatus shown in FIG.

FIG. 4 is a schematic sectional view showing an embodiment of another plasma processing apparatus to which the present invention can be applied.

FIG. 5 is a schematic sectional view showing the shape of another exhaust path (four-way exhaust) according to the present embodiment.

FIG. 6 is a schematic sectional view showing the shape of another exhaust path (four-way exhaust) according to the present embodiment.

FIG. 7 is a schematic sectional view showing the shape of another exhaust path (two-way exhaust) according to the present embodiment.

FIG. 8 is a schematic sectional view showing the shape of another exhaust path (two-way exhaust) according to the present embodiment.

FIG. 9 is a schematic sectional view showing a conventional plasma processing apparatus.

[Explanation of symbols]

 102 processing chamber 104 processing equipment 106 plasma generation chamber 112 waveguide 114 first gas supply pipe 116 second gas supply pipe 118 third gas supply member 122 inner wall member 123 overhang member 126 exhaust port 128 rectifier plate 130 mounting table 138 drive Mechanism 152 Rotation drive motor 154 Controller 158 Translation drive motor W Wafer

Claims (3)

[Claims] A plasma generation chamber; and a plasma processing chamber, wherein plasma excited in the plasma generation chamber is introduced into the plasma processing chamber. In a plasma processing apparatus that performs plasma processing, at least a part of an inner wall of the processing chamber is configured as a tapered surface that extends outward toward an upper side of the processing object, and forms a part of an exhaust path. An exhaust system having one or more exhaust ports is connected above the tapered surface. 2. The plasma processing apparatus according to claim 1, wherein an overhang member having a surface substantially parallel to the tapered surface is attached to a ceiling surface of the processing chamber. 3. The plasma processing apparatus according to claim 1, wherein a rectifying plate is provided in the exhaust path to make the flow of the exhaust gas uniform.