JPH0417675A - Ecr plasma cvd apparatus - Google Patents

Abstract

PURPOSE:To uniformize the distribution of plasma and to efficiently form film by providing a magnetic field impressing surface in the position parpendicular to a microwave introducing window, and forming a plasma drawing-out opening facing the magnetic field impressing surface. CONSTITUTION:Micro wave is introduced into the plasma chamber 1 consisting of nonmagnetic electroconductive material from the window 2 consisting of electrically insulating material through a rectangular wave guide 3, and moreover magnetic field is impressed by a magnetic field impressing mechanism part 7 through the magnetic field impressing surface 10. By this method, the introduced gas A, such as Ar, is made into plasma by ECR resonance. This plasma is introduced into a film formation chamber 4 from a plasma drawing-out opening 5 to excite an introducted gas B, such as SiH4. Thus, Si, etc., is formed into the film on a base plate 6. In the above- mentioned ECR plasma CVD apparatus, the magnetic field impressing surface 10 is made to be perpendicular to the surface of the introducing window 2 and to be confronted to the plasma drawing-out opening 5. By this method, the direction of magnetic field is diverged to the direction perpendicular to Z-axis, and the plasma is expanded as a whole, and film is uniformly formed on the base plate of optional shape according to the shape of the plasma drawing-out opening 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ECR plasma CVD apparatus that utilizes ECR (electron cyclotron resonance).

[Prior Art] A film forming method using ECR (Electron Cyclotron Resonance) has the advantage of being able to generate highly active gas species that are ionized in a large proportion under low gas pressure, so it is suitable for semiconductor processing. It is desired to be applied to

To date, there are two methods: placing a substrate in a place where the plasma is confined by a mirror magnetic field, etc., to form a film, and a method in which a coil is installed around the outer periphery of a cylindrical plasma chamber to generate ECR plasma, and ions are generated by the divergent magnetic field of the coil. Although extraction film deposition methods are known, the cylindrical plasma chamber ECR plasma CVD method is more suitable for use in semiconductor processes due to the compactness of the equipment and the low energy of particles incident on the substrate. it is conceivable that.

The mechanism and advantages of film formation by the ECR plasma CVD method will be described with reference to the cylindrical plasma chamber ECR plasma CVD apparatus shown in FIG. 10, which uses microwaves of 2.45 GHz. FIG. 1O shows a sectional view of the device, and FIG. 11 shows a view from the micro waveguide side.

Microwave (2.45 GHz) is applied to a cylindrical plasma chamber 63 (inner diameter 20 cm, length 20 am) using a rectangular waveguide 60.
), and magnetic coils 61 and 62 are provided around the circumferential surface of the plasma chamber 63, so that the magnetic field is almost parallel to the central axis of the cylinder in the plasma chamber, and the sample in the deposition chamber 64 is introduced from the plasma extraction port 66. The magnetic field (
(indicated by the dashed line) diverge.

Next, the operation will be explained.

Plasma chamber 63 at a pressure of 10-'' to 10-' Torr.
Inside, ionized electrons move in a circular motion in a magnetic field.

Electron cyclotron frequency ωc = eB/m (e: electron charge, B: magnetic flux density, m: electron quality ji) When microwave frequency ω and ωC become the same, EC
When the R condition is satisfied, microwave energy is effectively injected into the circularly moving electrons and they continue to be accelerated over many cycles. These high-energy electrons collide with gas molecules and strongly promote ionization, generating a large amount of excited, radicalized, and ionized highly active molecular species.

Since circularly moving electrons exhibit diamagnetic properties, high-energy circularly moving electrons in the plasma chamber are accelerated in the direction of a weak magnetic field, generating a negative potential in the direction of the sample stage. Ions in the plasma chamber are drawn out in the direction of the sample substrate table 65 by this electric field.

The advantages of the above-mentioned ECR plasma CVD method compared to the conventional plasma CVD method will be described.

■Since a large amount of highly active molecular species are generated, the film formation rate is faster (2 to 50 times). ■Because the ion extraction method using a divergent magnetic field is used, the energy of particles incident on the substrate is small (10 to 30 eV).
) The energy distribution is also small. Therefore, there is almost no damage to the substrate caused by high-energy (several hundred eV) incident particles that occurs in the conventional plasma CVD method.Also, although the energy of the incident particles is small, the incident Due to the high frequency and the presence of the highly active gas species, the substrate temperature can be lowered, and in most cases, a good quality film can be obtained even at room temperature, making it more applicable to semiconductor processes.

[Problem to be solved by the invention] However, the ECR with the cylindrical plasma chamber 63 described above is
The uniformity of film formation in the plasma CVD device is the center part 10c.
Although it is about ±5% in mφ, there is a problem that the uniformity deteriorates rapidly as the distance from the center increases.

It is difficult to use conventional ECR plasma CVD equipment as is to form films on long substrates with one side of loCQI or higher, which are applied to sensors and printers in image input/output devices, and cylindrical plasma CVD equipment is difficult. Since the coils 61 and 62 are located around the chamber 63, even if the above apparatus units are arranged in parallel, it is not possible to sufficiently shorten the distance between the plasma arches 066, making it impossible to form a film on a long substrate.

An object of the present invention is to provide an ECR plasma CVD apparatus that can form a film on a long substrate without sacrificing the advantages of the conventional ECR plasma CVD method.

[Means for Solving the Problem] In order to achieve the above object, the ECR plasma CVD of the present invention
The apparatus includes a plasma chamber made of a non-magnetic electrically conductive material and having a microwave introduction head made of an electrically insulating material, a film forming chamber spatially continuous with the plasma chamber through a plasma extraction port, and one side of the plasma chamber. is a magnetic field application surface, and a magnetic field application mechanism unit applies a magnetic field perpendicularly to the magnetic field application surface, and the magnetic field application surface is located perpendicularly to the surface on which the microwave introduction head is provided, and the plasma It is characterized in that the extraction port directly faces the magnetic field application surface.

Further, a magnetic field moving mechanism section that changes the position of the magnetic field applying mechanism section can also be provided.

Further, as shown in FIG. 4, the magnetic field application mechanism section 7 is composed of a magnetomotive force generating section 21 and a magnet section 25 consisting of a yoke 20 made of a high magnetic permeability material that guides the magnetic flux generated by the magnetomotive force generating section 21. , one magnetic surface 20-A of the magnetic circuit section is provided adjacent to the magnetic field application surface 10, and a magnetic surface 20-B having a polarity opposite to that of the magnetic surface 20-A is provided so as to be adjacent to the magnetic field application surface 10. It can also be provided so as to be located in a region opposite to the region in which the magnetic field application surface 10 is provided with reference to the surface including the plasma extraction port 5.

Furthermore, one or more magnetic field converging coils 23 may be provided outside the plasma extraction port 5 so that the central axis of the coil is located perpendicular to the plasma extraction port surface 5. A plurality of the above-mentioned unit structures are bonded to each other by adjoining each other or sharing a plate on the surface of the film-forming chamber other than the microwave introduction face, the magnetic field application face, and the plasma extraction port face to form a long substrate. It is also possible to form a film on.

[Example code] Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing a first embodiment of the present invention, and FIG. 2 is a sectional plan view thereof.

First, the configuration will be explained.

Roughly dividing the configuration of the present invention, a plasma chamber 1 made of a non-magnetic electrically conductive material, a film forming chamber 4 spatially continuous with the plasma chamber 1 through a plasma extraction port 5, and the plasma chamber 1
One surface thereof is a magnetic field application surface 10, and the magnetic field application mechanism section 7 applies a magnetic field perpendicularly to the magnetic field application surface 10.

Although the shapes of the plasma chamber 1 and the film forming chamber 4 are not particularly limited,
In FIG. 1, since the substrate on which the film is formed is rectangular, a rectangular parallelepiped is shown. The plasma chamber 1 and the film forming chamber 4 are made of non-magnetic metal such as aluminum or 5US3 (14) so that they can be evacuated to a high vacuum. It has a microwave introduction head 2 made of a quartz plate that is introduced into the chamber 1, and an introduction pipe 50 that introduces the introduced gas A.The microwave introduction head 2 has a microwave introduction head 2 that is made of a quartz plate and is introduced into the chamber 1. Further, the film forming chamber 4 has an introduction pipe 51 for introducing introduction gas B and a pipe 8 connected to a vacuum pump. The board stand 6 is fixed.

In the present invention, the magnetic field application mechanism section 7 is provided so that the direction of the applied magnetic field is perpendicular to the magnetic field application surface lO. The magnetic field application mechanism section 7 consists of an air-core coil 7-2 or a main magnet body 7-1, 7-2. Main magnet body 7-1.7-2
is I1. in coil 7-2. ．． Notebook made of low carbon steel.

One or more combinations of TLA stone passed through a yoke made of high magnetic permeability material such as pure iron, permanent magnets such as alnico or Ba ferrite, and magnets in which a permanent magnet and a yoke made of high magnetic permeability material are integrated. It consists of In addition, the magnetic field application surface 1
A hole is made in part or all of the surface directly facing 0 to serve as a plasma extraction port 5.

Next, the film forming operation will be explained.

Introducing gas A (N!, O□, Ar, l (e, etc.) that does not ionize and deposit in the plasma chamber 1 alone, and containing elements that will become part or all of the constituent elements of the film into the film forming chamber 4. Introduced gas B consisting of molecules (SiHn, Ga(CHs)
, As1(s.

Zn(CHs)t, 5e(CHs), etc.) are added. When a magnetic field is applied to the plasma chamber 1 and microwaves are injected into the plasma chamber 1, plasma is generated in which the introduced gas A is mainly ionized at a high rate. When the magnetic field of the magnetic field applying mechanism section 7 is applied here,
The magnetic field in the direction (two directions) perpendicular to the magnetic field application surface 10 is largest in the magnetic field application mechanism section, becomes smaller as it goes toward the substrate, and diverges in the direction in which the direction of the magnetic field is perpendicular to the two axes.

Due to the effect of this divergent magnetic field, ions in the plasma chamber 1 are extracted, and the introduced gas B is ionized, radicalized, and excited in the film forming chamber 4 to generate active species. These active species play a central role in causing a film formation reaction on the substrate, and a film is deposited.

Here, since the plasma chamber l is a rectangular parallelepiped, the plasma can be spread throughout the plasma chamber l by adjusting the shape of the applied magnetic field, and if the plasma extraction port 5 is formed in a rectangular shape close to the long substrate, the plasma can be The distribution shape roughly matches the shape of the plasma extraction port 5, allowing the plasma to be drawn out and efficiently formed into a film.

FIG. 3 shows a sectional view of a second embodiment of the invention.

The feature of this embodiment lies in the provision of a magnetic field moving mechanism section 15 that can vary the position of the magnetic field applying mechanism section 7.

This moving mechanism section 15 is not limited to a method of simply changing the screw fixing position and moving it, or a method using a linear slide mechanism, but the magnetic field applying mechanism section 7 is continuously operated by a motor drive or the like during film formation. including the method of moving the position,
Further, the direction of movement can be taken in each of the X-axis, Y-axis, and Z-axis directions in the figure. By changing the distribution of the magnetic field in this way, it is possible to improve the uniformity of plasma within the plasma chamber. Furthermore, when a mechanism is used to continuously change the magnetic field distribution during film formation, the uniformity of the plasma can be improved by averaging over time. Furthermore, the intensity distribution of the ion flow drawn into the film forming chamber can be adjusted, making it possible to uniformly form a film on a long substrate.

FIG. 4 shows a sectional view of a third embodiment of the present invention.

In the third embodiment, the magnetic field application mechanism section 7 includes a magnetomotive force generating section 21 that generates magnetomotive force using one or more coils, permanent magnets, etc., and a high magnetic permeability material such as low carbon steel or pure iron. The main magnet body 25 is composed of a yoke 20 made of material and a main magnet body 25 made of a material. In the main magnet body 25, a magnetic pole surface 20-A that generates a magnetic pole of one polarity of the yoke 20 is provided close to the magnetic field application surface 10.

Further, the yoke 20 is provided extending from the magnetic pole surface 20-A through the circumference of the plasma chamber to the vicinity of the substrate table 6, and has a single yoke that generates a magnetic pole of opposite polarity to the polarity toward the magnetic pole surface near the substrate. Or, the yoke 20 that has a plurality of magnetic pole surfaces 20-B and connects two types of magnetic pole surfaces is not limited to forming a magnetic circuit of two systems, but may also have a configuration that forms a magnetic circuit of multiple systems. I can do it.

In this embodiment, the magnetic flux generated by the magnetomotive force generating section 21 is efficiently guided to the magnetic pole face 20-A by the yoke 20, and a magnetic field having directivity in the X-axis direction is generated in the plasma chamber 1. Furthermore, since the magnetic pole surface 20-B has the effect of collecting most of the magnetic flux diverged in the plasma chamber 1 and the film forming chamber 4 onto the magnetic pole surface 20-B, by changing the position and shape of the Mi scratched surface 20B, the plasma chamber 1 and the shape of the divergent magnetic field in the film forming chamber 4 can be adjusted. In this way, the magnetic field in the plasma chamber 1 can be varied widely depending on the shape of the magnetic pole face 20-A, so the uniformity of the plasma in the plasma chamber 1 can be improved, a uniform ion flow can be obtained, and the film quality can be improved. uniformity can be improved.

Further, by using the yoke 20, the same magnetic field strength can be obtained with a small magnetomotive force, so that the magnetomotive force generating section can be made more compact.

Further, in this embodiment, one or more magnetic field converging coils 23 are provided around the plasma extraction port so that the center of the coil is located perpendicular to the surface of the plasma extraction port 5. The direction of the magnetic field generated by the coil 23 in the X-axis direction is made to be the same as the direction of the magnetic field generated by the magnetic field application mechanism section 7 in the X-axis direction.

By providing one or more magnetic field concentrating coils 23 in this way, the distribution of the magnetic field generated in the magnetic field applying mechanism section 7 can be adjusted, and the distribution of the strength of the plasma in the plasma chamber 1,
The size distribution of ion extraction into the film forming chamber 4 can be adjusted. Further, since the strength and distribution of the magnetic fields in the plasma chamber 1 and the film forming chamber 4 can be varied over a wide range, the uniformity of film quality on the long substrate can be improved.

5 to 8 show cross-sectional views of a fourth embodiment of the present invention.

5 and 6 are respectively Y-2 cross-sectional plan views of an embodiment in which the unit structures of the first embodiment are combined.

In this embodiment, which is a partially cutaway side view, basically the first
Two plasma chambers LA and IB are arranged in two units in the Y-axis direction as shown in the figure.
By dividing the film forming chamber 4 by a wall 55 and widening the film forming chamber 4, it is possible to accommodate a long film forming substrate 56.

7 and 8 are cross-sectional views taken along line X-2 of an embodiment in which the unit structures of the third embodiment are combined.

FIG. 3 is a partially cutaway plan view. FIG. 7 shows, based on the same concept as the embodiment shown in FIG. One pair is provided. In FIG. 8, four of the structural units shown in FIG. 7 are arranged in the Y-axis direction, so that the film forming chamber 4 can be made extremely long, and a film can be formed satisfactorily on an elongated rectangular substrate. In this way, since the compact configuration is used as a unit configuration, ions can be extracted from the plasma outlet ports of multiple unit configurations, and the unit configurations can be placed closer together compared to a cylindrical plasma chamber ECR plasma CVD device. Therefore, a film can be formed on a long substrate with good uniformity in the film chamber. This method is not limited to the embodiments shown in FIGS. 5 to 8 above, and the vacant surfaces (1 to 3 surfaces in the case of a rectangular parallelepiped) of the plasma chamber and film-forming chamber as a unit structure can be used to create a plurality of other unit structures. Various configuration patterns can be constructed by providing the board adjacent to the vacant surface of the board or sharing the board.

[Detailed Configuration Example] The dimensions and materials of each part of the device configuration shown in FIGS. 1 to 4 are as follows.

Plasma chamber dimensions (x220X ylol:jX z
llO++oa) Plasma outlet dimensions (x180X
y30) Microwave frequency (2,45 GHz) Magnetic field application mechanism section (X direction variable ±100 mm) Magnetomotive force generation section Coil current 2OA (30 m1 from magnetic surface A
Yoke member material: Soft iron Dimensions (x 140 x 760 mm) to magnetic surface d)) Magnetic field convergence coil The coil current is 10A (magnetic field convergence coil alone,
At the center of the plasma outlet, Z-direction magnetic flux density is 300 Gauss) Film formability dimensions: 300 x 300 x 30
0m1 Material 5U3304 Substrate-Plasma outlet distance (z150+++m)
Main pump 2000β/S turbo pump Introduced gas A Nt 603CCM Introduced gas B Sin, 205CCM Microwave power 800W Film forming pressure 7 A film with a film thickness distribution of ±5% was obtained within the range.

The etching rate distribution of the film was 360±5 persons/min in the range of 20×200 mm, and the film quality distribution was also good.

[Effects of the Invention] Hereinafter, according to the ECR plasma CVD apparatus of the present invention, the magnetic field application surface is located perpendicular to the surface on which the microwave introduction window is provided, and the plasma extraction port directly faces the magnetic field application surface. Therefore, it can be applied to film formation on long substrates without sacrificing the advantages of the conventional ECR plasma CVD method.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the first embodiment of the present invention, FIG. 2 is a sectional plan view of the first embodiment, FIG. 3 is a sectional view of the second embodiment, and FIG.
The figure is a sectional view of the third embodiment of the present invention, FIGS. 5 and 6 are sectional views and partially cutaway side views of an embodiment in which the unit structures of the first embodiment are combined, and FIGS. Figure 8 is a sectional view and partially cutaway plan view of an embodiment in which the unit configurations of the third embodiment are combined, Figure 9 is an explanatory diagram of a detailed configuration example, and Figures 10 and 11 are diagrams of a conventional ECR. FIG. 1 is a cross-sectional view and a side view of a plasma CVD apparatus. 1-plasma chamber, 2-microwave introduction chamber, 4-film formation chamber, 5-plasma extraction port, 7-magnetic field application mechanism section, 10
-Magnetic field application surface.杢 4 Genichi 〇圀v)l １〇■ rF54 圀 7 f '7M fig.v)q gall ichi 10 fig. η54i νmouth

Claims (1)

[Scope of Claims] A plasma chamber made of a non-magnetic electrically conductive material and having a microwave introduction tube made of an electrically insulating material, a film forming chamber spatially continuous with the plasma chamber at a plasma extraction port, and the plasma one side of the chamber is a magnetic field application surface, and a magnetic field application mechanism unit applies a magnetic field perpendicular to the magnetic field application surface, the magnetic field application surface being located perpendicular to the surface on which the microwave introduction head is provided, An ECR plasma CVD apparatus characterized in that the plasma extraction port directly faces the magnetic field application surface.