JPH07297176A - Method and apparatus for plasma treatment - Google Patents

Abstract

PURPOSE:To treat a large-area substrate, to be treated with good efficiency and uniformly by a plasma treatment method, especially a microwave plasma treatment method. CONSTITUTION:In a plasma treatment method, a plane slot antenna 2 and a multipole magnet 13 which is arranged and installed on the axial center extension of the plane slot antenna and which is composed of multipole magnet rings 12 in required stages are provided, microwave electric power is supplied to the plasma slot antenna, a reactive gas is changed into a plasma, and a substrate to be treated is treated. In the plasma treatment method, the substrate 7 to be treated is installed inside a space which is surrounded by the multipole magnet, and a plasma treatment is executed at high speed and uniformly in a high-density plasma region which is close to the plane slot antenna.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to dry etching, CVD (Chemical V
The present invention relates to a plasma processing method and an apparatus therefor for performing apordeposition), and particularly to a microwave plasma processing method and an apparatus therefor.

[0002]

2. Description of the Related Art Among plasma apparatuses which perform dry etching and CVD by making reactive gas into plasma and utilizing ionized active species, there is a method using microwave as a method for generating plasma.

As an example of a conventional microwave plasma processing apparatus, a permanent magnet type ECR (electron cyclotron resonance) plasma apparatus using a microwave of 2.45 GHz will be described with reference to FIG.

A back plate 1 is provided on the ceiling surface of the cylindrical vacuum container 1.
A plane slot antenna 2 is provided with 9 in between, and a coaxial waveguide 3, a rectangular-coaxial converter 20, and a rectangular waveguide 4 are connected to the plane slot antenna 2, and the rectangular waveguide 4 is further connected. The microwave power supply device 5 is connected. The plane slot antenna 2 is composed of a flat plate-shaped electrode having slots of a predetermined length and width for radiating microwaves, and the back plate 19 has a built-in permanent magnet in a direction parallel to the flat plate-shaped electrode. is doing. A substrate electrode 6 is provided on the bottom surface of the vacuum container 1, and a wafer is placed on the substrate electrode 6.
A substrate 7 to be processed such as a glass substrate is placed.

A reaction gas introduction pipe 8 is connected to the upper side wall of the vacuum container 1, and a reaction gas supply device 9 is provided through the reaction gas introduction pipe 8. An exhaust pipe 10 is connected to the lower side wall of the vacuum container 1, and an exhaust device 11 is provided through the exhaust pipe 10.

A multi-pole magnet 13 is provided on the inner wall of the vacuum container 1 from a substantially central portion to a lower portion thereof, and a multi-pole magnet ring 12 is provided at a required pitch along a required step (8 steps in the figure) along an inner wall surface. The multi-pole magnet ring 12 is constructed as an assembly of a large number of small magnets.

The inside of the vacuum container 1 is evacuated by the exhaust device 11, and while the reactive gas is introduced from the reaction gas supply device 9, the microwave is supplied from the microwave power supply device 5 to the rectangular waveguide 4, rectangular-coaxial. When supplied to the planar slot antenna 2 via the converter 20 and the coaxial waveguide 3, ECR plasma is generated by the magnetic field formed on the planar slot antenna 2 and the back plate 19. Using this plasma, the substrate 7 to be processed on the substrate electrode 6 is subjected to etching or CVD processing.

FIG. 2 shows a magnetic field generated between the planar slot antenna 2, the multi-pole magnet 13, and the substrate 7 to be processed during the above processing.

[0009]

However, in the conventional plasma processing method described above, in order to confine the plasma by the multi-pole magnet 13, the planar slot antenna 2 is used.
And the multi-pole magnet 13 must be separated by a predetermined distance, and effective containment requires about 8 multi-pole magnet rings 12, which results in a gap from the planar slot antenna 2 to the substrate electrode 6. The distance becomes extremely large, the device becomes complicated and large, and it is difficult to form a practical structure.

As shown in FIG. 3 as an example, the etching rate of the substrate 7 to be processed on the substrate electrode 6 is large at the center and small at the periphery when the substrate 7 is far from the end of the multi-pole magnet 13. It becomes a mountain shape and is not suitable for processing large-diameter substrates. On the contrary, when the substrate 7 to be processed is arranged at a position close to the end, the substrate 7 to be processed is located in the abrupt magnetic flux change region at the end of the multi-pole magnet 13 as shown in FIG.
Substantial deviations in the substrate position greatly change the processing characteristics, making stable processing practically difficult.

When the magnetic flux density of the magnet at the end of the multi-pole magnet ring 12 is gradually reduced toward the end face, the change in the magnetic field near the end face is alleviated to some extent.
The relaxation effect is not sufficient, and it is difficult to adjust so that a delicate gradient distribution is accurately and uniformly applied to the large-diameter multi-pole magnet ring 12.

The inner surface of the vacuum chamber 1 between the substrate 7 to be processed and the planar slot antenna 2 is almost occupied by the multi-pole magnet ring 12 on the side close to the substrate electrode 6, and the substrate inlet and the substrate practically required for the plasma processing apparatus are provided. It is difficult to provide an exhaust port.

In view of the above situation, the present invention is intended to efficiently and evenly process a large area substrate by a microwave plasma processing method.

[0014]

SUMMARY OF THE INVENTION The present invention comprises a plane slot antenna and a multipole magnet comprising a multipole magnet ring of a predetermined stage arranged on an extension of the plane slot antenna axis. In a plasma processing method of supplying microwave power to a slot antenna to convert a reactive gas into plasma to process a substrate to be processed, the substrate to be processed is placed in a space surrounded by the multi-pole magnet to perform plasma processing. It is characterized by performing.

[0015]

Since the substrate to be processed is installed in the space surrounded by the multi-pole magnets, high-speed and uniform plasma processing is performed in the high-density plasma region close to the plane slot antenna.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the same components as those shown in FIG. 4 are designated by the same reference numerals.

A rear plate 19 is provided on the ceiling surface of the cylindrical vacuum container 1.
A planar slot antenna 2 is provided with the interposition of a coaxial waveguide 3, a rectangular-coaxial converter 20, and a rectangular waveguide 4 connected to the planar slot antenna 2, and the rectangular waveguide 4 is further connected.
A microwave power supply device 5 is connected to the. The plane slot antenna 2 is composed of a flat plate electrode provided with slots of a predetermined length and width for radiating microwaves, and has a built-in permanent magnet in a direction parallel to the flat plate electrode. A substrate electrode 6 is provided on the bottom surface of the vacuum container 1 via an electrode base leg 14, and a substrate 7 to be processed such as a wafer or a glass substrate is placed on the substrate electrode 6.

A multi-pole magnet 13 is provided by embedding a multi-pole magnet ring 12 in a required step (8 steps in the figure) on an inner wall surface at a required pitch from a substantially central portion to a lower end of a side wall of the vacuum container 1. ing. The multi-pole magnet ring 12 is constructed as an assembly of a large number of small magnets.

The substrate electrode 6 is supported by the electrode base leg 14 so as to be positioned slightly on the plane slot antenna 2 side from the axial center of the multipole magnet 13, and the substrate to be processed placed on the substrate electrode 6 is supported. The upper surface of 7 is located between the third step and the fourth step of the multi-pole magnet ring 12. A substrate loading / unloading port 16 is provided on the side of the electrode base leg 14, and a substrate transporting device 17 is connected to the substrate loading / unloading port 16. The supporting position of the substrate 7 to be processed is set at the third stage and the fourth stage of the multi-pole magnet ring 12.
The position is not limited to the step, but may be any position as long as the magnetic flux becomes uniform, and it is needless to say that the number is changed by changing the number of steps of the multi-pole magnet ring 12.

The substrate loading / unloading port 16 is provided with a gate valve 15 which moves in the vertical direction, and the substrate loading / unloading port 1
6 is opened and closed by the gate valve 15,
The substrate transfer device 17 carries in and out the substrate 7 to be processed through the gate valve 15.

The gate valve 15 is embedded with a multi-pole magnet arc portion 12 'which constitutes a part of the multi-pole magnet ring 12 of the first to third stages, and the gate valve 15 causes the substrate loading / unloading port 16 to be carried out. Complete 1st stage ~ 3
The multi-pole magnet ring 12 of the stage is completed. The multi-pole magnet arc portion 12 'embedded in the gate valve 15 is not limited to the first to third stages,
It goes without saying that the second to second stages, the first to fourth stages, etc. may be appropriately changed according to the shapes of the substrate loading / unloading port 16 and the gate valve 15.

Since the multi-pole magnet is composed of an assembly of a large number of small magnets, an arbitrary portion can be made into a divided structure, and as described above, the multi-pole magnet 13 is penetrated,
It is possible to adopt a structure capable of easily carrying in and out the substrate 7 to be processed and exhausting gas.

A reaction gas introducing pipe 8 is connected to the upper side wall of the vacuum container 1, and a reaction gas supply device 9 is provided through the reaction gas introducing pipe 8. An exhaust port 18 is formed in a side wall of a lower end portion of the vacuum container 1, an exhaust pipe 10 is connected to the exhaust port 18, and an exhaust device 11 is provided through the exhaust pipe 10.
Is provided. The exhaust port 18 is located at the lower end of the side wall of the vacuum container 1 and at the same time, is located at the lower end of the multi-pole magnet 13. Therefore, a part of the multi-pole magnet ring 12 of the required stage located below (in this embodiment, it is 2
A part of the multi-pole magnet ring 12 of the stage passes through the exhaust port 18. The portion of the multi-pole magnet ring 12 that passes through the exhaust port 18 is floating in the exhaust port 18.

The gate valve 15 is opened, the substrate 7 is inserted into the vacuum container 1 from the substrate loading / unloading port 16 by the substrate transfer device 17, and the substrate 7 is placed on the substrate electrode 6. The loading / unloading port 16 is closed.

The inside of the vacuum container 1 is evacuated by the exhaust device 11, and while the reactive gas is introduced from the reaction gas supply device 9, the microwave is supplied from the microwave power supply device 5 to the rectangular waveguide 4, rectangular-coaxial. When supplied to the planar slot antenna 2 via the converter 20 and the coaxial waveguide 3, ECR plasma is generated by the magnetic field formed on the planar slot antenna 2 and the back plate 19. Using this plasma, the substrate 7 to be processed on the substrate electrode 6 is subjected to etching or CVD processing.

By installing the substrate 7 to be processed in the space surrounded by the multi-pole magnets 13, it is possible to perform an etching process in a high density plasma region close to the plane slot antenna 2. If the position of the substrate 7 to be processed in the multi-pole magnet 13 is above or below the end of the multi-pole magnet 13, the influence of the magnetic flux change at the end of the multi-pole magnet 13 is large and unsuitable. For this reason, the inside of three rows is suitable.

Specifically, as shown in FIG. 2, the diameter of the plane slot antenna 2 is 30 cm, the bottom surface of the plane slot antenna 2 is 37 cm from the bottom surface of the vacuum container 1, and the multi-pole magnet ring 12 is from the bottom surface of the plane slot antenna 2. It is buried between 15 cm and 37 cm.

First, the substrate 7 to be processed is placed on the multi-pole magnet 1
By adopting the structure installed inside 3, the etching process can be performed in the high density plasma region close to the plane slot antenna 2.

In the specific example shown in FIG. 3, when the substrate 7 to be processed is placed at a position 23 cm from the lower surface of the plane slot antenna 2, the diameter is 22 cm as compared with the position 45 cm from the lower surface of the plane slot antenna in the conventional method. An extremely uniform etching rate distribution could be obtained within the above range. However, it is closer to the antenna 1 apart from the multi-pole magnet 13
At a position less than 5 cm, for example, 10 cm, the uniformity was adversely affected by the influence of the slot pattern distribution.

Next, when the substrate 7 to be processed is installed at a position exceeding 30 cm below the lower surface of the plane slot antenna 2, both the etching rate and the uniformity are deteriorated as compared with the case of 23 cm, which is about the same as the conventional method. The installation position of the processing substrate 7 is 20 cm or more from the bottom surface of the plane slot antenna 2 30
cm or less is most suitable.

The installation position of the multi-pole magnet 13 is
If the end of the multi-pole magnet is less than 12 cm from the plane slot antenna 2, the plasma confinement effect is weak, and conversely it is 18 cm.
If it exceeds, the distance between the substrate 7 to be processed placed inside the multi-pole magnet 13 and the antenna also increases, and the processing speed decreases, which is inconvenient. Therefore, the position of the end of the multi-pole magnet is 12 cm or more from the plane slot antenna 2.
18 cm or less is suitable.

In the above embodiment, the multi-pole magnet ring 12 has eight steps, but it may have seven steps or less, or nine steps or more. Of course, the position of the pole magnet 13 and the size and shape of the vacuum container 1 are not limited to those in the above embodiment.

The multi-pole magnet ring 12 may be provided so as to project from the wall surface of the vacuum container 1, but it is embedded as shown in FIG. 1 in order to prevent the impure component from being mixed into the plasma due to the contact between the plasma and the magnet. Preferably. Also, the exposed surface of the multi-pole magnet ring 12 may be thinly covered with a cover plate (material such as quartz, alumina, or aluminum). Further, the exhaust port 18 may be provided not on the side wall of the vacuum container 1 but on the bottom surface.

[0035]

As described above, according to the present invention, since the substrate to be processed is installed in the space surrounded by the multi-pole magnet, a practical plasma in a high density plasma region close to the plane slot antenna is obtained. Processing is possible, a high-speed and uniform plasma processing speed distribution can be obtained, and since the multi-pole magnet is composed of an assembly of many small magnets, an arbitrary part is divided into structures to carry in / out the substrate and to remove gas. It is possible to take a structure that allows easy evacuation, has a small volume of the vacuum container, can have a compact structure, and can realize an economical device configuration, thus exhibiting excellent effects.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a magnetic field generated in a vacuum container.

FIG. 3 is a diagram showing an etching rate distribution in a radial direction.

FIG. 4 is a schematic cross-sectional view showing a conventional example.

[Explanation of symbols]

 1 vacuum container 2 plane slot antenna 6 substrate electrode 7 substrate to be processed 12 multi-pole magnet ring 13 multi-pole magnet 14 electrode stand 15 gate valve 16 substrate loading / unloading port 18 exhaust port

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H01L 21/31 H01P 5/103 H01Q 13/10 H05H 1/46 C 9014-2G

Claims (9)

[Claims] 1. A planar slot antenna, and a multipole magnet, which is arranged on an extension of the axis of the planar slot antenna and is composed of a multipole magnet ring of a predetermined stage, wherein microwave power is supplied to the planar slot antenna. In a plasma processing method of supplying a reactive gas into plasma to process a substrate to be processed, the substrate to be processed is placed in a space surrounded by the multi-pole magnet to perform plasma processing. Processing method. 2. The plasma processing method according to claim 1, wherein the substrate to be processed is installed at a position closer to the plane slot antenna than the central position of the multipole magnet in the axial direction. 3. The plasma processing method according to claim 1, wherein the substrate to be processed is arranged inside three or more stages of the multipole magnet ring from the plane slot antenna side of the multipole magnet. 4. A plane slot antenna, a multipole magnet which is arranged on an extension of the axis of the plane slot antenna and is composed of a multipole magnet ring at a required stage, and a substrate to be processed is supported in the multipole magnet. Substrate electrode,
A gate valve provided with a multi-pole magnet arc portion that forms a part of the multi-pole magnet ring while opening and closing the substrate loading / unloading port, and supplies microwave power to the planar slot antenna to generate a reactive gas. A plasma processing apparatus which processes a substrate to be processed by converting it into plasma. 5. The plasma processing apparatus according to claim 4, wherein the multi-pole magnet ring is embedded in the side wall of the vacuum container. 6. The plasma processing apparatus according to claim 4, wherein the exposed surface of the multi-pole magnet ring is covered with a cover plate. 7. The plasma processing apparatus according to claim 4, wherein an exhaust port is provided at a required position of the multi-pole magnet. 8. A multi-pole magnet has an 8-step multi-pole magnet ring and has a plane slot antenna diameter of about 30 cm.
5. The plasma processing apparatus according to claim 4, wherein the distance between the planar slot antenna and the end of the multi-pole magnet is 12 cm or more and 18 cm or less. 9. The multi-pole magnet has an 8-stage multi-pole magnet ring, and the plane slot antenna is approximately 30 cm, and the distance from the surface of the plane slot antenna to the surface of the substrate to be processed installed on the substrate electrode is 20 cm or more and 30 cm or less. The plasma processing apparatus of claim 4, wherein