JPH08260157A - Plasma cvd device - Google Patents

Abstract

PURPOSE: To provide a plasma CVD device capable of allowing a film close to the lower end of a work to have almost the same direction and adhesive strength as those of a film at the upper part. CONSTITUTION: A reaction space 29 is demarcated by a second electrode 20 having a vessel shape. The mounting part 12 of a first electrode 10 and a work W are enclosed with the second electrode 20. A couple of auxiliary walls 27 are projected upward from the bottom wall 21 of the second electrode 20. The mounting part 12 of the first electrode 10 is arranged in a region A demarcated by the auxiliary walls 27. The mounting part 12 is projected from the upper edge of the auxiliary wall 27.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a plasma CVD apparatus for forming a film on a work.

[0002]

2. Description of the Related Art Plasma CVD, that is, chemical vapor deposition using plasma, has recently attracted attention as a method capable of forming a film on a work at a relatively low temperature, for example, room temperature. In a general apparatus that executes this plasma CVD, as disclosed in FIG. 3 of Japanese Utility Model Application Laid-Open No. Sho 64-13119, flat plate-shaped first and second electrodes are mutually connected in a grounded vacuum chamber. They are arranged in parallel. A high frequency power source is connected to the first electrode and the second electrode is grounded.
The inner space of the vacuum chamber is provided as a reaction space. A part of the reaction gas supplied into the reaction space becomes plasma by the high frequency electric field generated between the first electrode and the second electrode, and negative ions, that is, electrons in the plasma violently move by the high frequency electric field. . As a result, a part of the reaction gas is decomposed to generate radicals. A flat plate-shaped work is attached to the second electrode along the second electrode,
Positive ions and radicals adhere to the surface of this work to form a film.

In the above apparatus, since positive ions are not biased toward the work, the film formed on the work is
Low adhesive strength and thin. In addition, power is wasted due to the fact that a film is formed on the first electrode and the second electrode, and plasma is generated between the first electrode and the wall of the chamber facing the first electrode. It

A plasma CVD apparatus closer to the present invention is disclosed in Japanese Patent Application Laid-Open No. 5-311448.
In this device, the internal space of the vacuum chamber is divided into a plurality of pieces by a wire mesh. Each of the divided spaces is surrounded by the wall of the vacuum chamber and the wire mesh, and is provided as a reaction space. The vacuum chamber and the wire net are grounded and serve as a second electrode. A flat plate-shaped first electrode is housed in each of the reaction spaces. The first electrode is connected to a high frequency power supply via an impedance matching circuit. A work having a substantially cubic shape is placed on the upper surface of the first electrode. Positive ions in the plasma generated by the high-frequency electric field move toward the work based on the bias function of the impedance matching circuit, and radicals also move in the same direction along with the positive ions. As a result, a film is formed on the surface of the first electrode.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the apparatus disclosed in Japanese Patent No. 448, the upper surface of the plurality of surfaces of the work placed on the first electrode faces the second electrode, and the positive ions and radicals following the positive ions collide at a substantially right angle. Therefore, the film formed here has a strong adhesive strength and is thick. However, the coating formed on the surface of the workpiece orthogonal to the upper surface of the first electrode, particularly the coating formed on the lower end portion near the first electrode, has weak adhesion strength and is thin. The reason is that the positive ions and the radicals following them are attracted to the upper surface of the first electrode, so that the amount of collision with the lower end of the work is small, and that the oblique collision with the lower end of the work does not occur at right angles. It is estimated to be. Further, a film is formed on a wide area of the upper surface of the first electrode, and plasma generated in the space between the lower surface of the first electrode and the corresponding second electrode does not contribute to the film formation of the work at all. Due to
Power is wasted.

[0006]

The invention according to claim 1 is
(A) A first electrode having a mounting portion for mounting a conductive work, (b) a second electrode, and (c) a suction means for making a reaction space between the first electrode and the second electrode a vacuum. And (d) gas supply means for supplying a reaction gas to the reaction space, and (e) connected to the first electrode and supplying high-frequency power to the reaction space to generate plasma in the reaction space. In a plasma CVD apparatus provided with a high frequency power source and (f) a bias means for attracting positive ions of the plasma toward a work, the second electrode surrounds the attachment portion of the work and the first electrode, Further, the reaction chamber is shaped like a container so as to partition the reaction space and confine the plasma generated in the reaction space, and the second electrode having the container shape has an auxiliary wall that projects inward and defines an arrangement region. Existence The mounting portion of the first electrode is arranged in the arrangement region in a state of being electrically insulated from the auxiliary wall, and protrudes in a protruding direction of the auxiliary wall from a tip edge of the auxiliary wall. To do.

According to a second aspect of the present invention, in the plasma CVD apparatus according to the first aspect, a pair of auxiliary walls of the second electrode are provided facing each other with a space therebetween, and are partitioned by the pair of auxiliary walls. The mounting portion of the first electrode is arranged in the arrangement region.

According to a third aspect of the present invention, in the plasma CVD apparatus according to the second aspect, the work has a pair of flat surfaces parallel to each other, and the other surface of the work orthogonal to the flat surfaces is the first surface. The second electrode is provided as a contact surface in contact with the mounting portion of the one electrode, and the second electrode includes a pair of flat first opposing walls that face the pair of flat surfaces of the workpiece in a state where the workpiece is attached to the first electrode. A pair of auxiliary walls that face each other in parallel with the pair of first opposing walls, and a first connecting wall that connects the auxiliary walls to the corresponding first opposing wall. Is projected inward from the first connecting wall.

According to a fourth aspect of the present invention, in the plasma CVD apparatus according to the third aspect, a pair of flat surfaces of the work and the second electrodes respectively corresponding to the flat surface of the work are attached to the first electrode. And the distance between the pair of first opposing walls is equal to each other.

According to a fifth aspect of the present invention, in the plasma CVD apparatus according to the third aspect, the work has a top surface located on the opposite side of the contact surface and intersecting with the pair of flat surfaces. The electrode further has a second facing wall facing the top surface, and a pair of arc-shaped second connecting walls connecting the second facing wall to the pair of first facing walls. And

According to a sixth aspect of the present invention, in the plasma CVD apparatus according to the second aspect, the first electrode has an elongated shape and has a base portion disposed between the pair of auxiliary walls. The auxiliary wall and the first opposing wall extend in the same direction as the base portion, and the plurality of mounting portions are arranged at intervals in the extending direction of the base portion, and the portion of the base portion located between the mounting portions is It is characterized in that it is recessed from this mounting portion.

According to a seventh aspect of the present invention, in the plasma CVD apparatus according to the first aspect, the auxiliary wall has a cylindrical shape,
The attachment portion of the first electrode is arranged in the arrangement area defined by the auxiliary wall.

According to an eighth aspect of the present invention, in the plasma CVD apparatus according to the seventh aspect, the work has a substantially cylindrical shape, and one end face of the work is provided as a contact surface in contact with the mounting portion of the first electrode. The mounting portion of the first electrode has a cylindrical shape, the auxiliary wall of the second electrode has a cylindrical shape concentric with this mounting portion, and the second electrode further has a work piece attached to the first electrode. Has a cylindrical first opposing wall that is concentric with the auxiliary wall and that faces the peripheral surface of the first auxiliary wall, and a first connecting wall that connects the first opposing wall and the auxiliary wall. 1 It is characterized in that it protrudes inward from the connecting wall.

According to a ninth aspect of the invention, in the plasma CVD apparatus according to the eighth aspect, the second electrode faces the other end surface of the work in a state where the work is attached to the first electrode. A wall and a second connecting wall connecting the second facing wall to the first facing wall are provided, and the second connecting wall has a substantially hemispherical shell shape.

According to a tenth aspect of the present invention, in the plasma CVD apparatus according to the first aspect, the receiving surface for receiving the work at the mounting portion of the first electrode has a shape equal to the surface of the work facing the receiving surface. It is characterized in that the work is flush with the mounting portion when mounted on the mounting portion.

According to an eleventh aspect of the invention, in the plasma CVD apparatus according to the first aspect, the receiving surface for receiving the work at the mounting portion of the first electrode has a shape smaller than the surface of the work facing the receiving surface. The work is projected from the mounting portion toward the auxiliary wall in the state where the work is mounted on the mounting portion.

According to a twelfth aspect of the present invention, in the plasma CVD apparatus according to the first aspect, the second electrode has a flat plate-shaped common base portion having a plurality of insertion holes, and the insertion holes are surrounded by the base portion. And a plurality of hood portions that are mounted so as to cooperate with the base portion to partition the reaction space, and the tubular auxiliary wall that is provided in the base portion so as to surround the through hole in each hood portion. The first electrode has a base portion that is disposed on the opposite side of the hood portion and faces the base portion of the second electrode substantially in parallel, and a plurality of the attachment portions that protrude from the base portion of the first electrode. And each of the mounting portions is characterized in that it passes through the insertion hole of the base of the second electrode, passes through the auxiliary wall, and projects from the tip edge of this auxiliary wall.

[0018]

1 and 2 show a plasma CVD apparatus according to a first embodiment of the present invention. This plasma CVD apparatus is for forming a film on the conductive work W. This work W is, for example, a vane of a vane pump, and is formed by a rectangular flat plate (hexahedral). The work W has a pair of flat surfaces W1 and W2 that are parallel to each other and have a large area, a top surface W3, side surfaces W4 and W5, and a bottom surface W6. Surface W1 to W
5 is a surface on which a film is to be formed, and in particular, surfaces W1 and W
2 and W3 are required to have high wear resistance due to the coating. The bottom surface W6 is provided as a contact surface for the first electrode 10 described later, and no coating is formed on the bottom surface W6.

The above-mentioned device comprises a first electrode 10 and a second electrode 20.
It has. These electrodes are made of copper or stainless steel and extend in the direction orthogonal to the paper surface of FIG. The second electrode 20 is grounded, has a container shape for confining plasma, which will be described later, and its inner space serves as a reaction space 29. The second electrode 20 includes a horizontally-shaped rectangular bottom wall 21 (first connecting wall) and a pair of parallel side walls 22 (first opposing walls) that vertically rise from the long side of the bottom wall 21 as shown in FIG. Wall) and the bottom wall 21 as shown in FIG.
A pair of parallel side walls 2 that rise vertically from the short side of the
3, a horizontal rectangular top wall 24 (second opposing wall) having a narrow width, and an arcuate wall 25 (second connecting wall) connecting the top wall 24 to the pair of side walls 22. The side wall 2
2, 23, the top wall 24, and the arc wall 25 are integral with each other to form a hood portion 26. The hood portion 26 is detachably and airtightly attached to the bottom wall 21.

A pair of auxiliary walls 27 vertically project upward from the widthwise central portion of the bottom wall 21 of the second electrode 20.
These auxiliary walls 27 are parallel to the side wall 22 and
Has the same length as. A pair of auxiliary walls 2 separated from each other
An arrangement area A for arranging the first electrode 10 is defined between the seven. The distances between the pair of auxiliary walls 27 and the pair of side walls 22 facing each other are equal to each other.

As best shown in FIG. 2, the first electrode 10
Has a slender base portion 11, a plurality of, for example, three mounting portions 12 that project upward from the base portion 11, and a convex portion 13 that projects downward from the center of the base portion 11. The mounting portions 12 are arranged at equal intervals in the extending direction of the base portion 11, and the upper surface 12a (receiving surface) has the same shape as the bottom surface W1 of the work W described above. The upper surface 11 a of the portion of the base 11 located between the mounting portions 12 is lower than the upper surface 12 a of the mounting portion 12.

The first electrode 10 is arranged in the arrangement area A between the pair of auxiliary walls 27 of the second electrode 20. As shown in FIG. 1, both side surfaces of the first electrode 10 are provided with a pair of auxiliary walls 27.
, They are separated by an equal distance from each other. The first electrode 10 is shorter than the second electrode 20,
Both end surfaces of the first electrode 10 are provided with a pair of side walls 2 of the second electrode 20.
3 apart with equal spacing.

Between the pair of auxiliary walls 27 of the second electrode 20,
An insulator 30 such as ceramic is housed in the electrode 1
The electrical insulation between 0 and 20 is secured. The base portion 11 of the first electrode 10 is housed in a housing recess 30b formed in the upper surface 30a of the insulator 30. In this embodiment, the upper surface 30a of the insulator 30 and the upper surface 11a of the base 11 of the first electrode 10 are flush with the upper edge of the auxiliary cylinder 27 of the second electrode 20. Attachment part 12 of the first electrode 10
Protrudes upward from the upper edge of the auxiliary cylinder 27.

The convex portion 13 of the first electrode 10 is made of the insulator 3
0 through the through hole 30c formed in the central portion of the second electrode 20 and through the opening 21a formed in the bottom wall 21 of the second electrode 20 to project downward, where the high frequency power supply 31 is located. Connected through.

A gas introduction pipe 33 is provided in the second electrode 20, and a gas cylinder 34 (gas supply means) storing a reaction gas is connected to the pipe 33. An exhaust pipe 35 is attached to the second electrode 20, and a vacuum pump 36 (vacuum suction means) is connected to the pipe 35.

A process of forming a film of amorphous carbon on the work W with the apparatus having the above structure will be described. First, with the hood portion 26 of the second electrode 20 removed from the bottom wall 21, the work W is placed on each of the upper surfaces 12a of the three attachment portions 12 of the first electrode 10. In this embodiment, the convex portion 1 formed on the upper surface 12a and protruding upward
By fitting 2x into the hole formed in the bottom surface W6 of the work W, the work W is positioned and reliably supported. It should be noted that these protrusions 12x and holes may be omitted. The bottom surface W of the work W in the positioning state of the work W
6 and the upper surface 12a of the mounting portion 12 substantially coincide with each other, so that the surfaces W1, W2, W4, W5 of the work W are flush with the corresponding side surfaces of the mounting portion 12.

After mounting the work W, the hood portion 2
6 is attached to the bottom wall 21 in an airtight manner. In this state,
The pair of side walls 22 of the second electrode 20 face the two flat surfaces W1 and W2 of the work W in parallel with each other at the same distance D. In addition, the top wall 24 of the second electrode 20
Are facing each other at the same distance D. The arc wall 25 is
They are arranged on a circle (the radius of this circle is equal to the distance D) centered on the intersection of the surfaces W1 and W2 and the top surface W3.

A reaction space 29 surrounded by the second electrode 20.
Is vacuumized by driving the vacuum pump 36. A reaction gas, for example, a mixed gas of tetramethylsilane (TMS) and methane gas is supplied to the reaction space 29 from a gas cylinder 34. Further, high frequency power is supplied from the high frequency power supply 32 to the first electrode 10. At this time, since the work W has conductivity, it functions as a part of the first electrode 10.

Due to the high frequency power, a part of the gas in the reaction space 29 becomes plasma, and initially, negative ions, that is, electrons are mainly generated by the high frequency electric field, mainly the work W and the second electrode 2.
It reaches 0. The electrons reaching the second electrode 20 escape to the ground,
The electrons reaching the work W pass through the first electrode 10 and are stored in the capacitor of the impedance matching circuit 31. As a result, the work W and the first electrode 10 have a negative potential level and attract positive ions described later (self-bias). The potential level of the work W reaches a constant negative level and stabilizes.

In the vicinity of the first electrode 10 and the work W, since the center potential level is lower than a predetermined negative threshold value, plasma is not generated. The plasma is generated in the reaction space 29 excluding the space near the first electrode 10 and the work W.
In addition, a radical movement occurs mainly due to decomposition of a part of the gas due to the intense movement of electrons in the plasma.

The positive ions of the plasma proceed toward the work W due to the potential level gradient generated near the work W and collide with them. At this time, the radicals also follow the flow of positive ions and collide with the work W. Due to collision of these positive ions and radicals, as shown in FIG.
A film S having a uniform thickness is formed on the surfaces W1 to W5 of the work W with great adhesion strength.

The formation of the film S will be described in detail below. On the pair of flat surfaces W1 and W2 and the top surface W3 of the work W,
A pair of side walls 22 and a top wall 24 of the second electrode 20 face each other, and a space between the side wall 22 and the top wall 24 is covered with an arc wall 25. Therefore, the surfaces W1, W of the work W
Plasma is stably generated in the space surrounding W2 and W3. Moreover, since the potential gradient in the vicinity of the work W is generated so as to draw equipotential level lines that are substantially parallel to the respective surfaces W1, W2, W3 of the work W, positive ions are generated on these surfaces W.
1, W2, W3 can be made to collide with a large collision energy from the direction substantially orthogonal. As a result, the film S formed on these surfaces W1, W2, W3 is
It is thick and has high adhesion strength.

Since the flat surfaces W1 and W2 have the same distance D to the corresponding side wall 22, the thickness of the coating film S formed on the flat surfaces W1 and W2 can be made equal.

The formation of the film S on the lower ends of the flat surfaces W1 and W2 is as follows. The attachment portion 12 of the first electrode 10 is arranged in a narrow arrangement area A defined by the pair of auxiliary walls 27. Moreover, this mounting part 1
2 and the flat surfaces W1 and W2 of the work W are flush with each other, the same potential gradient as that at the upper portion can be obtained at the lower ends of the flat surfaces W1 and W2. Moreover, since the mounting portion 12 projects upward from the auxiliary wall 27, the potential gradient at the lower ends of the flat surfaces W1 and W2 is not significantly affected by the auxiliary wall 27. As a result, the film S formed on the lower ends of the flat surfaces W1 and W2
Can obtain the adhesive strength and the thickness which are not different from those of the upper part.

The formation of the film S on the side surfaces W4 and W5 is as follows. The side surfaces W4 and W5 of each work W are
It faces the side wall 23 or is separated from the other work W by a sufficient distance. In addition, the base portion 11 between the mounting portions 12
The upper surface 11a of the workpiece W is recessed, and the side surfaces W4 and W5 of the work W are
And the side surface of the mounting portion 12 are flush with each other. Therefore, a relatively good coating S can be formed on the side surfaces W4 and W5.

Next, the significance of existence of the auxiliary wall 27 will be described in detail. In order to favorably form the film on the lower end portion of the work W, it may be considered that the first electrode 10 is projected and exposed from the bottom wall 21 of the second electrode 20 without forming the auxiliary wall 27. . In this case, in order to eliminate the influence of the horizontally extending bottom wall 21 on the potential gradient in the vicinity of the work W, the first electrode 10 is largely projected upward from the bottom wall 21, and the work W is largely separated from the bottom wall 21. There is a need. However, in such a configuration, the first protrusion protruding from the bottom wall 21 is exposed.
A film is formed on the wide surface of the electrode 10, resulting in waste of power consumption.

In the present embodiment, the auxiliary wall 27 covers most of the first electrode 10. Since the auxiliary wall 27 does not extend horizontally in the horizontal direction, the amount of protrusion by which the potential gradient near the lower end portion of the work W can avoid the influence from the auxiliary wall 27 (attachment of the first electrode 10 from the upper edge of the auxiliary wall 27). (Projection amount of part 12)
Can be small. Therefore, the area of the first electrode 10 exposed in the reaction space 29 can be minimized, and the power consumption due to the film formation on the first electrode 10 can be minimized.

Since the second electrode 20 has a container shape and defines the reaction space 29 to confine the plasma, the generated plasma can be effectively utilized, and this also saves power consumption. Further, since the film can be formed on the three works W at the same time, the productivity is high. In addition, in the present embodiment, the second electrode 20 cooperates with the first electrode 10 and the insulator 30 to form a vacuum chamber, so that a vacuum chamber surrounding the second electrode 20 is not required separately, The device can be downsized.

A film forming experiment was carried out by the apparatus shown in FIGS. In this experiment, the work W is 40 mm × 2
A vane made of 0 mm × 5 mm hexahedral aluminum alloy was used. The dimensions of the device are as follows. The height of the auxiliary wall 27 is 20 mm, the distance between the auxiliary wall 27 and the first electrode 10 is 3 mm, and the protrusion amount of the mounting portion 12 from the upper edge of the auxiliary wall 27 is 5 mm. The receiving surface 12a of the mounting portion 12 has a rectangular shape of 20 mm × 5 mm. With the three works W attached to the first electrode 10, the work W is arranged at an interval of 40 mm, and the side surface W of the work W on the left side in FIG.
The distance between 4 and the side wall 23 and the distance between the side surface W5 of the work W on the right side and the other side wall 23 are 20 mm, respectively. Further, the distance between the flat surfaces W1 and W2 of each work W and the corresponding side wall 22 is 35 mm, and the distance between the top surface W3 and the top wall 24 of the work W is also 35 mm.

Other conditions are as follows. Source gas CH ₄ + TMS (tetramethylsilane) Gas pressure 8Pa Input power 150W (13.56MHz) Gas flow CH ₄ : 5sccm TMS: 0.7sccm (however, sccm is standard cubic centimeter / min) Film formation time 2 hours

As a result of the above experiment, the thickness of the amorphous carbon film S formed on the top surface W3 of the work W is 10 μm,
It was substantially uniform over the entire top surface W3. The thickness of the coating S formed on the flat surfaces W1 and W2 and the side surfaces W4 and W5 was 7 μm (± 0.5 μm), and the thickness of the coating S on each surface was uniform. The adhesive strength of the coating film S on these surfaces W1 to W5 was measured as a peeling load by a scratch test, and it was 30 N. It should be noted that the larger the peeling load, the higher the adhesion strength.

Next, a comparative experiment will be described. The first and second electrodes are each formed of a disk having a diameter of 180 mm, are horizontal to each other, and are vertically separated from each other at an interval of 65 mm. These electrodes are housed in a vacuum chamber. One work W is placed on the center of the upper surface of the lower first electrode. Work W
The dimensions and other conditions are the same as the experiment in the apparatus of the present embodiment. In this comparative experiment, the thickness of the film S on the top surface W3 of the work W was 6 μm, which was uniform over the entire region. The thickness of the coating film on the surfaces W1, W2, W4, W5 decreased toward the lower end and was 4 μm at maximum and 1 μm at minimum. The peeling load was 30 N on the top surface W3 and about 10 N on the other surfaces W1, W2, W4 and W5.

As is clear from the comparison of the above two experimental results, according to the apparatus of this example, significant improvements were recognized in both the thickness of the coating and the adhesive strength.

The work W is placed inside the container-shaped second electrode 20.
You may install only one. In this case, the first electrode 10 and the second electrode 20 are formed short, and the two side walls 23 of the second electrode 20 face the two side surfaces W4 and W5 of the work W, respectively. The auxiliary wall may be formed in a tubular shape having a rectangular cross section so as to surround the attachment portion 12 of the first electrode 10.

As shown in FIGS. 4A and 4B, the upper surface 12a of the mounting portion 12 may be smaller than the bottom surface W6 of the work W. In this case, the peripheral portion of the bottom surface W6 horizontally projects from the mounting portion 12 to form a step. This step does not significantly affect the potential gradient at the lower end of the work W.

As shown in FIGS. 5A and 5B, the upper surface 12a of the mounting portion 12 may be smaller than the bottom surface W6 of the work W. In this case, the peripheral portion of the upper surface 12a projects horizontally from the work W to form a step. This step does not significantly affect the potential gradient at the lower end of the work W as long as it is within a predetermined protrusion amount range.

In the device shown in FIG. 6, the insulator 30 is housed between the auxiliary walls 27, and the upper surface of the insulator 30 and the auxiliary wall 2 are accommodated.
The upper edges of 7 are at the same height. A plurality of first electrodes 10 are fixed to the upper surface of the insulator 30 so as to project from the auxiliary wall 27. These first electrodes 10 are provided as the mounting portion 12 as they are. With this device, the same operational effects as those of the embodiment shown in FIGS. 1 and 2 can be obtained.

The second electrode may be formed of a wire mesh in a container shape so that only the plasma is confined. In this case, the second electrode is housed in a vacuum chamber, and a gas supply cylinder and a vacuum pump are connected to this vacuum chamber. The protruding direction of the attachment portion of the auxiliary wall and the first electrode may be horizontal.
In this case, a special attachment means is required to attach the work to the attachment portion.

The apparatus shown in FIGS. 7 and 8 is for forming a film on a cylindrical work W ′ such as a drill or a pin. One end surface W1 'of this work W'becomes a contact surface in contact with a first electrode 50, which will be described later, and the peripheral surface W2' and the other end surface W3 'are film formation target surfaces.

The above device is a first device made of copper or stainless steel.
The electrode 50 and the second electrode 60 are provided. Second electrode 60
Is a disk-shaped horizontal base portion 61 (first connecting wall)
A plurality of, for example, four hood portions 62 detachably attached to the upper surface of the base portion 61, and the hood portions 6
A horizontal disc-shaped connecting plate 63 for connecting the upper ends of the two and a cylindrical auxiliary wall 64 fixed to the upper surface of the base part 61 in the hood part 62 are provided.

A plurality of, for example, four through holes 61a are formed in the base portion 61 at equal angular intervals in the circumferential direction, and a plurality of, for example, five gas outflow holes 61b are provided at positions distant from the through holes 61a. Has been formed. A net 61c is attached to the gas outflow hole 61b. The auxiliary wall 64 is fixed to the peripheral edge of the insertion hole 61a so as to concentrically surround the insertion hole 61a. Further, a cylindrical mounting tube 65 is fixed to the upper surface of the base portion 61 so as to be concentric with the insertion hole 61a and the auxiliary wall 64.

Each hood portion 62 cooperates with the base portion 61 to define a reaction space 69. The hood portion 62 defines a cylinder 66 (first facing wall) and a hemispherical shell shape fixed to the inner circumference of the middle portion of the cylinder 66. Cup 67 (second connecting wall). The top portion 67a (second facing wall) of the cup 67 is flat and formed of a net. The hood portion 62 is attached to the base portion 61 by fitting the lower end portion of the hood portion 62 into the attachment cylinder 65. In this state, the cylinder 66 has the insertion hole 61a.
It is arranged concentrically with the auxiliary wall 64.

The upper end of the cylinder 66 of the hood 62 and the top 67a of the cup 67 are attached to the lower surface of the connecting plate 63. A gas introduction hole 63a is formed in the connecting plate 63 so as to correspond to the top portion 67a of the cup 67. A gas cylinder (not shown) is connected to the gas introduction hole 63a via a pipe 80 extending upward.

The first electrode 50 has a base portion 51 arranged horizontally and a cylindrical mounting portion 52 which vertically projects from the upper surface of the base portion 51. The base portion 51 of the first electrode 50 is mounted on parallel disk-shaped insulators 70. A ring-shaped convex portion 71 protruding upward is formed on the peripheral portion of the insulator 70. The base portion 61 of the second electrode 60 is placed on the upper surface of the convex portion 71. As a result, the base portion 51 of the first electrode 50 is spaced below the base portion 61 of the second electrode 60 at a narrow interval.
And parallel.

The mounting portion 52 of the first electrode 50 passes through the insertion hole 61a of the base portion 61 of the second electrode 60, the auxiliary wall 64, and projects upward from the upper edge of the auxiliary wall 64. The mounting portion 52 is concentrically separated from the auxiliary wall 64.

A convex portion 53 is formed at the center of the lower surface of the base portion 51 of the first electrode 50. The convex portion 53 penetrates the insulator 70 and projects downward, and the impedance matching circuit 32 is provided there. The high frequency power supply 31 is connected via the.

The first electrode 50, the second electrode 60 and the insulator 70 are housed in a vacuum chamber 90. A vacuum pump (not shown) is connected to the vacuum tank 90.

A process of forming a film of amorphous carbon on the work W'by using the apparatus having the above structure will be described. First, with the hood portion 62 of the second electrode 60 removed from the base portion 61, all the attachment portions 5 of the first electrode 50 are attached.
The workpieces W'are placed on the upper surfaces 52a (reception surfaces) of the two and positioned. In the positioning state of the work W ′, the bottom surface W1 ′ of the work W ′ and the top surface 1 of the mounting portion 12
2a substantially coincide, and as a result, the peripheral surface W of the work W '
2'is flush with the peripheral surface of the mounting portion 52.

After attaching the work W ', the hood portion 62 is attached to the base portion 61. In this state,
The cylinder 66 of the second electrode 60 faces the peripheral surface W2 ′ of the work W ′ in parallel with the same distance D ′ over the entire circumference. Further, the top portion 67a of the cup 67 faces the top surface W3 ′ of the work W ′ with the same distance D ′.

After attaching the hood portion 62, the vacuum chamber 90 is closed, the vacuum pump is driven, and the reaction gas is supplied from the gas cylinder. This reaction gas is connected to the connecting plate 6.
3. The net top 67 of the cup 67 from the gas introduction hole 63a of No. 3
The reaction space 69 is entered via a. Then, it passes between the auxiliary wall 64 and the mounting portion 52, and the insertion hole 61 b of the base portion 61.
Through the base parts 51 and 61, and the gas discharge hole 61.
It is discharged from b into the vacuum chamber 90. In this state, high frequency power is supplied from the high frequency power supply 32 to the first electrode 50.

The plasma generation, the radical generation, and the bias of the positive ions to the work are substantially the same as those in the first embodiment, and the description thereof will be omitted. The positive ions and radicals proceed toward the work W ′ due to the potential level gradient generated near the work W ′, and collide with the peripheral surface W2 ′ and the top surface W3 ′. By the collision of the positive ions and the radicals, a film having a uniform thickness is formed on the surfaces W2 'and W3' of the work W'with a large adhesion strength.

The formation of the film will be described in detail below. The second electrode 6 is provided on the peripheral surface W2 ′ and the top surface W3 ′ of the work W ′.
The cylinder 66 of 0 and the top portion 67a of the cup 67 face each other, and the space between the cylinder 66 and the top portion 67a is covered by the cup 67. Therefore, the surface W of the workpiece W '
Plasma is stably generated in the space surrounding 2'and W3 '. Moreover, the potential gradient in the vicinity of the workpiece W'is
2 ', the top surface W3' is generated by drawing an equipotential level line almost parallel to the top surface W3 '.
It is possible to make a collision with a large collision energy from a direction substantially orthogonal to W3 '. As a result, the films formed on these surfaces W2 'and W3' are thick and have high adhesion strength.

The peripheral surface W2 'has a corresponding cylindrical surface 6
Since the distance D ′ up to 6 is equal over the entire circumference, the thickness of the film formed on the circumferential surface W2 ′ can be made uniform in the circumferential direction.

The film formation on the lower end of the peripheral surface W2 'is as follows. Attachment part 52 of the first electrode 50
Are arranged in a narrow arrangement area defined by a cylindrical auxiliary wall 64. Moreover, since the peripheral surface of the mounting portion 52 and the peripheral surface W2 ′ of the work W ′ are flush with each other,
At the lower end of the peripheral surface W2 ', a potential gradient similar to that at the upper part can be obtained. Moreover, the mounting portion 52 projects upward from the auxiliary wall 64, and the potential gradient at the lower end portion of the peripheral surface W2 ′ is the auxiliary wall 6.
Not significantly affected by 4. As a result, the peripheral surface W2 '
The film formed at the lower end of the film can have the same adhesive strength and thickness as those of the upper part.

It should be noted that the devices of FIGS. 7 and 8 can also save power for the same reason as in the first embodiment. Further, the film formation of the four works W ′ can be performed simultaneously, and the productivity is high.

A film forming experiment was conducted by using the apparatus shown in FIGS. In this experiment, the work W'has a diameter of 10 m.
A high speed cutting tool having a length of m and a length of 30 mm was used. The dimensions of the device are as follows. The height of the auxiliary wall 64 is 20 mm, and the distance between the auxiliary wall 64 and the mounting portion 52 of the first electrode 50 is 3 m.
The amount of protrusion of the mounting portion 52 from the upper edge of the auxiliary wall 64 is 5 mm. The receiving surface 52a of the mounting portion 52 has a diameter of 1
It has a circular shape of 0 mm. Work W'is the first electrode 50
The distance between the peripheral surface W2 ′ of the workpiece W ′ and the corresponding cylinder 66 is 35 mm, and the distance between the end surface W3 ′ of the workpiece W and the top 67a of the cup 67 is 3 mm.
It is 5 mm.

Other conditions are as follows. Raw material gas CH ₄ + TMS (tetramethylsilane) Gas pressure 8 Pa Input power 150 W (13.56 MHz) Gas flow CH ₄ : 5 sccm TMS: 0.7 sccm Film formation time 2 hours

As a result of the above experiment, the top surface W3 'of the work W'is
The thickness of the amorphous carbon film formed on the surface was 10 μm, and was substantially uniform over the entire top surface W3 ′. The thickness of the film formed on the peripheral surface W2 'is 7 μm (±
0.5 μm), and the thickness of the coating was uniform over the entire area. The peeling load of the film on these surfaces W2 'and W3' was both 30N.

Next, a comparative experiment will be described. In this comparative experiment, the device used in the comparative experiment with the first example was used as it was. The work W ′ was placed at the center of the first electrode.
In this comparative experiment, the thickness of the film on the top surface W3 ′ of the work W ′ was 6 μm and was uniform over the entire area. The thickness of the coating film on the peripheral surface W2 ′ decreased toward the lower end, and was 5 μm at maximum and 1 μm at minimum. The peeling load was 30 N on the top surface W3 ′ and about 10 N on the peripheral surface W2 ′.

As is clear from the comparison of the above two experimental results, the apparatus shown in FIGS. 7 and 8 showed a significant improvement in both the film thickness and the adhesive strength.

Also in the above embodiment, the upper surface 5 of the mounting portion 52 is
The diameter of 2a may be smaller than or slightly larger than the end surface W1 'of the work W'. Further, the work W ′ may be installed horizontally.

[0072]

As described above, according to the invention of claim 1, the second electrode is formed into a container shape so as to surround the mounting portion of the first electrode and the work, and this mounting portion serves as an auxiliary of the second electrode. Since it is placed in the placement area defined by the wall and is projected from the tip edge of the auxiliary wall,
The thickness and adhesion strength of the film formed near the electrode
There is substantially no difference from the part away from the first electrode, which can be satisfied.

According to the second aspect of the present invention, since the arrangement region is defined by the pair of auxiliary walls corresponding to the width of the work, it is suitable particularly when two surfaces of the work are the coating target surfaces. According to the third aspect of the present invention, when the pair of flat surfaces of the work are used as the coating formation surfaces, the coating can be formed on each flat surface with a substantially uniform thickness and a substantially uniform adhesive strength. According to the invention of claim 4, the film thickness of the pair of flat surfaces of the work can be made equal to each other. According to the invention of claim 5, a good film can be formed on the top surface of the work. According to the invention of claim 6, it is possible to simultaneously form a film on a plurality of works and improve productivity. According to the invention of claim 7, since the auxiliary wall has a tubular shape, a good film can be formed on all surfaces of the work corresponding to the auxiliary wall. According to the invention of claim 8, a good film can be formed on the entire peripheral surface of the cylindrical work. According to the invention of claim 9,
A good film can be formed on the top surface of a cylindrical work. According to the inventions of claims 10 and 11, it is possible to more reliably form a good film at the lower end of the work. According to the twelfth aspect of the present invention, it is possible to simultaneously form a film on a plurality of works and improve productivity.

[Brief description of drawings]

FIG. 1 is a sectional view showing a plasma CVD apparatus for forming a film on a flat plate-shaped work according to an embodiment of the present invention.

FIG. 2 is a sectional view of the device taken along line II-II in FIG.

FIG. 3 is a vertical cross-sectional view of a work after forming a film, in which the film thickness is exaggerated.

FIG. 4 shows another aspect of the shapes of the work and the mounting portion,
(A) is a side view and (B) is a plan view.

5A and 5B show still another aspect of the shapes of a work and a mounting portion, FIG. 5A being a side view and FIG. 5B being a plan view.

FIG. 6 is a view corresponding to FIG. 1 showing another embodiment.

FIG. 7 is a vertical cross-sectional view showing a plasma CVD apparatus for forming a film on a cylindrical work.

8 is a sectional view taken along the line VIII-VIII in FIG.

[Explanation of symbols]

 W, W'Work W1, W2 Flat surface W3 Top surface W6 Bottom surface (contact surface) W1 'Bottom surface (contact surface) W2' Circumferential surface W3 'Top surface 10 First electrode 11 Base portion 12 Mounting portion 12a Top surface (receiving surface) 20 2nd electrode 21 Bottom wall (1st connecting wall) 22 Side wall (1st facing wall) 24 Top wall (2nd facing wall) 25 Arc wall (2nd connecting wall) 27 Auxiliary wall 29 Reaction space 31 High frequency power supply 32 Impedance Matching circuit (bias means) 34 gas cylinder (gas supply means) 36 vacuum pump (vacuum suction means) 50 first electrode 51 base portion 52 mounting portion 60 second electrode 61 base portion (first connecting wall) 61a insertion hole 64 auxiliary wall 66 Cylinder (first opposing wall) 67 Cup (second connecting wall) 67a Top (second opposing wall)

Claims (12)

[Claims] 1. A first electrode having a mounting portion for mounting a conductive work, and a second electrode.
(C) Suction means for making the reaction space between the first electrode and the second electrode a vacuum; (D) Gas supply means for supplying a reaction gas to the reaction space; and (E) For the first electrode. By connecting and supplying high frequency power to the reaction space,
A high-frequency power source that generates plasma in this reaction space,
(F) Bias means for attracting positive ions of the plasma toward the work, the second electrode surrounding the attachment portion of the work and the first electrode, and the reaction space. And has a container shape so as to confine plasma generated in the reaction space by partitioning the container, and the container-shaped second electrode has an auxiliary wall that projects inward to partition the arrangement region, The mounting part of the first electrode is
A plasma CVD apparatus, wherein the plasma CVD apparatus is arranged in the arrangement region in a state of being electrically insulated from the auxiliary wall, and protrudes from a tip edge of the auxiliary wall in a protruding direction of the auxiliary wall. 2. A pair of auxiliary walls of the second electrode are provided so as to be spaced apart from each other and face each other, and a mounting portion for the first electrode is arranged in an arrangement area defined by the pair of auxiliary walls. The plasma CVD apparatus according to claim 1, wherein: 3. The work has a pair of flat surfaces parallel to each other, and the other surface of the work orthogonal to the flat surfaces is provided as a contact surface in contact with the mounting portion of the first electrode. The electrodes face the pair of flat first opposing walls facing the pair of flat surfaces of the workpiece in a state where the workpiece is attached to the first electrode and the pair of first opposing walls in parallel with each other. It has a pair of above-mentioned auxiliary walls and the 1st connecting wall which connects these auxiliary walls to the corresponding 1st counter wall, and each auxiliary wall is projected inward from this 1st connecting wall. The plasma CVD apparatus according to claim 2. 4. The work is attached to the first electrode, and the distance between the pair of flat surfaces of the work and the pair of first facing walls of the second electrode corresponding to the flat surfaces is equal to each other. The plasma CVD apparatus according to claim 3, wherein 5. The work has a top surface located on the opposite side of the contact surface and intersecting with the pair of flat surfaces, and the second electrode further has a second facing wall facing the top surface. ,
The plasma CVD apparatus according to claim 3, further comprising a pair of arc-shaped second connecting walls that connect the second opposing wall to the pair of first opposing walls. 6. The second electrode includes a base portion disposed between the pair of auxiliary walls, the first electrode extending in a slender shape, and the second electrode.
The auxiliary wall and the first opposing wall of the electrode extend in the same direction as the base portion, the plurality of mounting portions are arranged at intervals in the extending direction of the base portion, and are located between the mounting portions in the base portion. The plasma CVD apparatus according to claim 2, wherein the portion is recessed from the mounting portion. 7. The plasma CV according to claim 1, wherein the auxiliary wall has a cylindrical shape, and the mounting portion of the first electrode is arranged in an arrangement region defined by the auxiliary wall.
D device. 8. The work has a substantially cylindrical shape, one end surface of which is provided as a contact surface in contact with the mounting portion of the first electrode, and the mounting portion of the first electrode has a cylindrical shape and the second electrode. The auxiliary wall has a cylindrical shape that is concentric with the mounting portion, and the second electrode has a cylindrical shape that confronts the peripheral surface of the workpiece and is concentric with the auxiliary wall when the workpiece is attached to the first electrode. It has a 1st facing wall and a 1st connecting wall which connects this 1st facing wall and an auxiliary wall, and said auxiliary wall is projected inward from this 1st connecting wall, It is characterized by the above-mentioned. Item 7. A plasma CVD apparatus according to Item 7. 9. The second electrode comprises a second opposing wall facing the other end surface of the workpiece in a state where the workpiece is attached to the first electrode, and a second opposing wall connecting the second opposing wall to the first opposing wall. Two
9. The plasma C according to claim 8, further comprising a connecting wall, wherein the second connecting wall has a substantially hemispherical shell shape.
VD device. 10. A receiving surface for receiving a work at the mounting portion of the first electrode has a shape equal to a surface of the work facing the receiving surface, and the work is attached to the mounting portion. The plasma CV according to claim 1, wherein the plasma CV is flush with the mounting portion.
D device. 11. A receiving surface for receiving a work in the mounting portion of the first electrode has a shape smaller than a surface of the work facing the receiving surface, and the work is attached in the mounting portion to the mounting surface. The plasma CVD apparatus according to claim 1, wherein the plasma CVD apparatus projects from the attachment portion toward the auxiliary wall. 12. The second electrode includes a common flat plate-shaped base portion having a plurality of insertion holes, and is attached to the base portion so as to surround the insertion holes, and cooperates with the base portion to partition the reaction spaces. A plurality of hood portions and a cylindrical auxiliary wall provided in the base portion so as to surround the through hole in each hood portion, and the first electrode is substantially the same as the base portion of the second electrode. The base part is disposed on the opposite side of the hood part in parallel to each other, and the plurality of mounting parts projecting from the base part of the first electrode, and each mounting part inserts the base of the second electrode. The plasma CVD apparatus according to claim 1, wherein the plasma CVD apparatus is configured to pass through the hole, pass through the auxiliary wall, and project from a leading edge of the auxiliary wall.