JP2002004056A - Plasma enhanced film deposition system for conductive metallic thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma enhanced film deposition system for conductive metallic thin film, with which a conductive metallic thin film of nearly uniform thickness can be effectively deposited on a flexible resin sheet by using a small cathode electrode and further cost reduction can be attained by miniaturizing the system itself. SOLUTION: The plasma enhanced film deposition system is constituted of: an anode electrode and the cathode electrode which are relatively arranged at a prescribed space in a reactor vessel; an introducing part for introducing metallic compound gas into the reactor vessel; a vacuum aspirator for evacuating the reactor vessel; and a DC power unit for applying DC high voltage between the anode electrode and the cathode electrode to generate glow discharge. The cathode electrode is provided with a couple of grooves of prescribed width at a prescribed space, and the flexible resin sheet fed through one groove is fed out through the other groove, and the conductive metallic thin film can be deposited on the surface of the flexible resin sheet while making the sheet travel in the negative glow layer region on the cathode electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for forming a conductive metal thin film on a plasma, and more particularly to an apparatus for forming a conductive metal thin film on a surface of a flexible resin sheet by plasma.

[0002]

The applicant of the present invention has disclosed, for example, in Japanese Unexamined Patent Publication No. Hei 6-330295, a vacuum vessel and a negative electrode and a positive electrode which are arranged so that discharge surfaces face each other in the vacuum vessel. Exhaust means for bringing the inside of the vacuum vessel into a high vacuum state, gas introducing means for diffusing a raw material gas obtained by gasifying a metal compound into the vacuum vessel made into a high vacuum state, and direct current between the negative electrode and the positive electrode. A plasma film forming apparatus comprising a high voltage applying means for performing glow discharge, and depositing and depositing cationized metal molecules on the surface of a substrate disposed in a negative glow phase region to form a metal thin film has been proposed.

[0003] In this plasma film forming apparatus, a metal film is deposited on a substrate at a high density to form a film. It is suitable for forming a conductive metal thin film equivalent to an ITO film formed on a substrate such as an IC chip.

In recent years, for example, when manufacturing a light transmitting electrode plate for a liquid crystal or a solar cell, a conductive metal thin film is formed on the surface of a flexible resin sheet using the above-mentioned plasma film forming apparatus. However, in the above-described plasma film forming apparatus, when the cationized metal molecules are deposited on the substrate on the negative electrode, they are cationized at the center compared to the outer peripheral side of the positive column. The density of metal molecules tends to be low. For this reason, the metal thin film formed on the substrate has a problem that the outer peripheral side is thicker than the central portion of the negative electrode and the film thickness is not uniform. As a result, there is a problem that the electrical resistance of the metal thin film formed on the substrate cannot be made uniform and cannot be used as an electrode plate.

[0005] This disadvantage can be solved by using a negative electrode having an area approximately three times or more as large as the film forming area of the flexible resin sheet. However, the plasma film forming apparatus itself becomes large and the cost is high. Was inevitable.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional drawbacks. An object of the present invention is to use a small negative electrode on a flexible resin sheet with a substantially uniform thickness. It is an object of the present invention to provide a conductive metal thin film plasma forming apparatus capable of efficiently forming a conductive metal thin film.

Another object of the present invention is to provide an apparatus for forming a plasma of a conductive metal thin film, which can reduce the size of the apparatus itself and reduce the cost.

[0008]

According to the present invention, there are provided a positive electrode and a negative electrode which are disposed in a reaction vessel at a predetermined distance from each other, and an introduction part for introducing a metal compound gas into the reaction vessel.
In a plasma film forming apparatus comprising a vacuum suction device for vacuum suction inside the reaction vessel, and a DC power supply device for applying a high DC voltage between the lifting electrode and the negative electrode to generate a glow discharge,
The negative electrode is provided with a pair of grooves having a predetermined width and a predetermined interval, and the flexible resin sheet fed from one groove is sent out from the other groove to form a negative glow layer region on the negative electrode. Wherein a conductive metal thin film can be formed on the surface while running the flexible resin sheet.

[0009]

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

Embodiment 1 In FIGS. 1 to 5, a reaction vessel 3 of a plasma film forming apparatus 1 is shown.
Is a cylindrical glass part 5 made of pressure-resistant glass, and a top plate part 7 which is detachably attached to the upper part of the cylindrical glass part 5 and is attached in an airtight manner.
And a substrate portion 9 which is detachably attached to the lower portion of the cylindrical glass portion 5 and is attached in an airtight manner. A positive electrode 11 is attached to the lower surface of the central portion of the top plate 7 in an electrically insulated state, and a discharge leakage prevention cylinder 13 is provided around the positive electrode 11 except for a discharge surface (a lower surface shown in the figure).

A sublimation chamber 15 is attached to the lower surface of the top plate 7 located around the positive electrode 11, and a source gas introduction part 17 is provided in a part of the sublimation chamber 15, and is opposite to the source gas introduction part 17. In the sublimation chamber 15 on the side, a source gas outlet 19 is provided.

An organic or inorganic metal compound crystal powder is charged into the raw material gas introduction section 17, and the charged metal compound crystal powder sublimates and fills the sublimation chamber 15.

Examples of the metal of the metal compound include Group I (Au, Ag, Cu) and Group II (Mg, Zn,
Cd), Group III (B, Al, Ga, In, Y), IV
Group (Ti, Si, Ge, Sn, Pb), group V (V, N
b, Ta, As, Sb, Bi), group VI (Cr, Mo,
W, Se), Group VII (Mn), Group VIII (Os, I
r, Pt, Pd, Rh, Co, Ni, Fe) and the like. A preferred example of the present embodiment is osmium tetroxide (OsO ₄ ).

The source gas outlet 19 has a structure in which the degree of opening to the reaction vessel 3 can be adjusted by a needle valve or the like.
The gas concentration (pressure) of the metal compound supplied into the reaction vessel 3 can be adjusted by rotating the needle valve.

A negative electrode 21 is mounted on the upper surface of the central portion of the substrate portion 9 in an electrically insulated state, and a discharge leakage prevention cylinder 23 is mounted around the negative electrode 21 except for the electrode surface (upper surface). The central part of the negative electrode 21 penetrates in the vertical direction,
Two grooves 25 and 27 having a predetermined width are formed in parallel at a predetermined interval. One groove 25 constitutes a feed passage for a flexible resin sheet 29 described later, and the other groove 27 constitutes a feed passage for the flexible resin sheet 29. These grooves 25
The width and spacing of 27 are set so that the exposed area of the flexible resin sheet 29 located between the grooves 25 and 27 is about 30 to 40% of the upper surface of the negative electrode 21.

On the upper surface of the negative electrode 21 corresponding to the upper portions of the grooves 25 and 27, turning rollers 31 and 33 project from the upper surface of the negative electrode 21 at a height corresponding to a negative glow layer region described later and can be rotated. And the upper surface of the flexible resin sheet 29 supported by the turning rolls 31 and 33 is positioned within the negative glow layer (about 1 to 6 mm from the upper surface of the negative electrode). Also,
Turning rollers 35 and 37 are rotatably supported below the grooves 25 and 27.

A supply roll 39 on which a flexible resin sheet 29 is wound is rotatably supported in the reaction vessel 3 corresponding to the side of the negative electrode 21 on the groove 25 side. A tension roll 41 is provided in the delivery passage of the flexible resin sheet 29 so as to always apply a constant tension while sandwiching the flexible resin sheet 29. A take-up roll 45 is rotatably supported in the reaction vessel 3 corresponding to the side of the negative electrode 21 on the groove 27 side. The take-up roll 45 is provided rotatably with respect to the reaction vessel 3 in an airtight manner, and is detachably connected to a drive shaft 49 connected to an electric motor 47 mounted outside the reaction vessel 3.

The flexible resin sheet 29 may have any flexibility as long as it is an electrically insulating material. Preferred examples thereof include polypropylene and polyethylene.

The flexible resin sheet 29 fed from the supply roll 39 is stretched so as to be wound on a winding roll 45 via the turning roll 35, the groove 25, the turning roll 31, the groove 27, and the turning roll 37. And the electric motor 47
The flexible resin sheet 29 is rotated by the take-up roll 45 which is rotated with the driving of the
・ Run at a predetermined speed between 27.

The substrate section 9 is provided with a suction connection port 51 to which an exhaust pipe 51a from a vacuum suction device (not shown) is connected so as to communicate with the inside of the reaction vessel 3, and the reaction vessel is driven by the vacuum suction device. 3 at a predetermined vacuum pressure (1 × 10 ⁻⁶ To
rr).

The positive electrode 11 is connected to the (+) pole of the DC power supply 53, and the negative electrode 21 is connected to the (-) pole of the DC power supply 53. The DC power supply 53 is connected to the positive electrode 11 and the negative electrode 21. A DC high voltage of about 0.6 to 3 KVDC is applied to generate a DC glow discharge.

Next, the operation of forming a conductive thin film on the flexible resin sheet 29 by the plasma film forming apparatus 1 will be described.

First, the vacuum suction device is driven to drive the reaction vessel 3
After the inside is brought into a high vacuum state, a sublimation gas of osmium oxide filled in the sublimation chamber 15 is introduced into the reaction vessel 3 by operating a needle valve of the raw material gas outlet section 19 to reduce the gas pressure in the reaction vessel 3. Adjust to about 0.01-0.1 Torr.

While the gas is being introduced into the reaction vessel 3 via the raw material gas outlet 19, the vacuum suction device is finely driven to balance the gas pressure in the reaction vessel 3 with the above value.

Next, in the above state, a high DC voltage is applied between the positive electrode 11 and the negative electrode 21 to generate a DC glow discharge therebetween, thereby cationizing osmium molecules in the sublimation gas of osmium oxide. Generate plasma.

In this state, when the electric motor 47 is driven and controlled to cause the flexible resin sheet 29 stretched between the supply roll 39 and the take-up roll 45 to run at a constant speed at a minute speed, the negative electrode 21 The flexible resin sheet 29 located between the groove 25 and the groove 27 on the upper surface runs in the negative glow layer of the DC glow discharge in a state charged with (-) charge, and deposits and fixes cationized osmium molecules on the upper surface. . (See Fig. 5)

At this time, the current applied between the positive electrode 11 and the negative electrode 21 is a value for ionizing (ionizing) the osmium molecules, and is relatively determined from the relationship between the thickness of the conductive metal thin film and the film forming time. Adjust it. Now, when the osmium oxide gas concentration in the reaction vessel 3 is 0.01 to 0.1 Torr,
DC voltage applied between the positive electrode 11 and the negative electrode 21 is 1
1.5 KV, ion current density 30-100 μA / c
When m ² , an osmium thin film is deposited and formed on the surface of the flexible resin sheet 29 at 5 to 50 nm / 120 sec. Flexible resin sheet 2 on which osmium thin film is formed
When 9 is used as a transparent electrode sheet for liquid crystals and solar cells, a film thickness of 15 to 20 nm is required to make the electric resistance equivalent to that of the ITO thin film. Since the thickness of the osmium thin film largely depends on the discharge time between the positive electrode 11 and the negative electrode 21, the discharge time may be adjusted to obtain a desired film thickness.

Since the flexible resin sheet 29 running between the groove 25 and the groove 27 runs in a negative glow layer 1 to 6 mm from the upper surface of the negative electrode 21, osmium molecules radicalized in the negative glow layer are Although it also wraps around and deposits on the lower surface of the flexible resin sheet 29 running between the grooves 25 and 27,
Since the density of the osmium molecules in the plasma is higher at a position shifted from the center of the flexible resin sheet 29 to the edge in the width direction, the osmium molecules tend to be deposited and fixed on the edge in the width direction of the flexible resin sheet 29.

For this reason, after the osmium thin film is formed, the flexible resin sheet 2 taken out of the reaction vessel 3
By cutting and removing the width-direction edge of No. 9, it is possible to obtain a flexible resin sheet 29 in which an osmium thin film is formed with a predetermined thickness on only one surface.

Since the osmium thin film formed on one surface of the flexible resin sheet 29 is formed in an amorphous state, the osmium thin film has a characteristic of having an extremely low electric resistance value even with a small thickness. For this reason, when the flexible resin sheet 29 is used as a transparent electrode sheet for liquid crystal on which an osmium thin film is formed, for example, the transparent electrode sheet itself can be thinned.

Embodiment 2 Embodiment 1 has a structure in which the supply and take-up mechanism of the flexible resin sheet 29 is integrally accommodated in the reaction vessel 3, whereas the plasma film forming apparatus 60 of this embodiment has a reaction In addition to the container 3, a first sub-container 63 having a supply mechanism 61 for the flexible resin sheet 29 built therein and a second sub-container 67 having a winding mechanism 65 built therein are provided.

That is, as shown in FIGS. 6 and 7, the first sub-container 63 containing the supply mechanism 61 is provided on the lower side surface of the reaction vessel 3.
And the second sub-container 67 containing the winding mechanism 65 is provided so as to be parallel to the grooves 25 and 27 in the negative electrode 21 respectively.

The first sub-container 63 and the second sub-container 67 are connected to the lower part of the reaction container 3 through openings 69 and 71 so that they can communicate with each other. Doors 73 rotatably supported by the sub-containers 67, respectively.
-It is closed airtight by 75.

Each of the first sub-container 63 and the second sub-container 6
7 has a supply roll 81 and a take-up roll 83
The openings 77 and 79 are sized so that the doors 85 and 87 can be taken out, and the openings 77 and 79 are configured to be airtightly closed by doors 85 and 87.

The first sub-container 63 contains a flexible resin sheet 2
The supply roll 81 on which the supply roll 9 is wound is detachably and rotatably supported, and the flexible resin sheet 29 wound on the supply roll 81 is sandwiched by a pair of rollers 89. An electric motor 91 is connected to one of the pair of rollers 89, and the flexible resin sheet 29 sandwiched by the driving of the electric motor 91 runs.

The take-up mechanism 65 accommodated in the second sub-container 67 has a take-up roll 83 for taking up the flexible resin sheet 29 and a pair of guides for sending and guiding the flexible resin sheet 29 to be taken up. It comprises a roll 93 and an electric motor 95 connected to the winding roll 83 and rotating the winding roll 83 in the winding direction.

The substrate section 9 corresponding to the lower part of each of the grooves 25 and 27 has a guide block 97 for guiding the flexible resin sheet 29 to the groove 25 and a roll 93 for feeding the flexible resin sheet 29 delivered from the groove 27. Guide blocks 99 for guiding to the sides are respectively attached. An arm 103 having a guide 101 attached to the distal end thereof is rotatably supported on the side of the cathode 21, and the guide 101 has a flexible surface sent out from the groove 25 on a surface facing the cathode 21. Resin sheet 29
A guide concave portion 101a is formed to feed the front end portion into the groove 27. The shaft 105 of the arm 103 is the cylindrical glass part 5
It is projected outward and is rotated by a handle 107 attached to the shaft end.

The plasma device 60 forms a conductive metal thin film on the flexible resin sheet 29 as follows. Since the function of forming the conductive metal thin film on the flexible resin sheet 29 is the same as that of the first embodiment, a detailed description thereof will be omitted.

Flexible resin sheet 29 for negative electrode 21
When the doors 73 and 75 are rotated to open the openings 69 and 71 communicating with the reaction vessel 3 in an airtight manner, the door 85 is opened to open the first through the opening 77. The supply roll 81 is mounted in the sub-container 63 such that the front end of the wound flexible resin sheet 29 is sandwiched between the rollers 89.

The supply roll 81 is placed in the first sub-container 63.
Is attached, the inside of the reaction vessel 3 is maintained in a vacuum state by driving the vacuum exhaust device.

Next, after the opening 77 is airtightly closed by the door body 85, the pair of doors 73 and 75 are rotated to open the openings 69 and 71.
The vacuum evacuation device is driven in a state where is opened, and the inside of the first sub-container 63 and the second sub-container 67 is formed in the same vacuum state as in the reaction container 3.

In the above state, the arm 103 is rotated to operate the guide 101, and the guide recess 101a is
The roller 89 is positioned above the grooves 25 and 27 in FIG.
Is rotated to feed the flexible resin sheet 29 wound around the supply roll 81 into the reaction container 3 through the opening 69. The flexible resin sheet 2 sent into the reaction vessel 3
9 is fed into the groove 25 by the guide block 97 and reaches above the negative electrode 21.
After being curved by 1a and being introduced into the groove 27 and reaching below the negative electrode 21 (see FIG. 8), the guide block 9
The winding roll 83 is rotated by driving the electric motor 95 that has passed through the opening 71 while being curved and guided by 9.

In the present embodiment, when the flexible resin sheet 29 is attached to the cathode 21 or replaced,
While maintaining the vacuum state in the reaction vessel 3, the first sub-container 63
Only the first and second sub-containers 63 and 67 can be evacuated when the film forming operation is started. As a result, the transition time to the film forming operation can be greatly reduced as compared with the case where the reaction vessel 3 is formed together with the first and second sub-containers 63 and 67 in vacuum.

[0044]

According to the present invention, a conductive metal thin film having a substantially uniform thickness can be efficiently formed on a flexible resin sheet using a small negative electrode. In addition, the size of the apparatus itself can be reduced to reduce the cost.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a plasma film forming apparatus according to the present invention.

FIG. 2 is a central longitudinal sectional view of the plasma film forming apparatus.

FIG. 3 is a perspective view showing a structure of a negative electrode.

FIG. 4 is a sectional view taken along line III-III of FIG. 3;

FIG. 5 is an explanatory diagram showing a film forming operation.

FIG. 6 is an overall perspective view showing a plasma film forming apparatus according to a second embodiment.

FIG. 7 is a central longitudinal sectional view of FIG. 6;

FIG. 8 is an explanatory view showing a mounted state of a flexible resin sheet.

[Explanation of symbols]

1.60-plasma film forming apparatus, 3-reaction vessel, 11-lift electrode, 15-sublimation chamber, 21-negative electrode, 25-27-groove,
29-flexible resin sheet, 39-supply roll, 45-take-up roll, 61-supply mechanism, 63-first sub-container, 65
-Winding mechanism, 67-second sub-container

Claims (6)

[Claims] 1. A positive electrode and a negative electrode, which are disposed at predetermined intervals in a reaction vessel, an introduction section for introducing a metal compound gas into the reaction vessel, and a vacuum suction apparatus for vacuum-suctioning the inside of the reaction vessel. And a DC power supply device for generating a glow discharge by applying a high DC voltage between the lifting electrode and the cathode, wherein the cathode has a pair of grooves with a predetermined width and a predetermined interval. The flexible resin sheet sent from one groove is sent out from the other groove, and the flexible resin sheet runs on the surface of the negative resin in the negative glow layer region on the negative electrode. Plasma deposition equipment for conductive metal thin films that enables metal thin films to be formed. 2. The metal compound according to claim 1, wherein the metal compound is Group I, Group II, Group III, Group IV, Group V, or Group VI of the Periodic Table of the Elements.
A plasma film forming apparatus for forming a conductive metal thin film comprising an organic or inorganic compound and any one of metals selected from the group consisting of a group VII, a group VII and a group VIII. 3. The plasma deposition apparatus according to claim 2, wherein the metal compound is osmium oxide. 4. The flexible resin sheet according to claim 1, wherein the flexible resin sheet between the pair of grooves is about 30 to 4 with respect to the entire area of the negative electrode.
A plasma film forming apparatus for a conductive metal thin film having an area ratio of 0%. 5. A reaction roll according to claim 1, wherein a supply roll having a flexible resin sheet wound on a feed groove side of the reaction vessel is rotatably supported, and a flexible resin sheet winding roll is provided on a send groove side. Is a conductive metal thin film plasma film forming apparatus which is rotatably supported so that a flexible resin sheet can run on a negative electrode. 6. A plasma film forming apparatus for a conductive metal thin film according to claim 1, wherein a sub-vacuum chamber provided with a flexible resin sheet supply mechanism and a winding mechanism is detachably provided in the reaction vessel.