JPH07138747A - Formation of film - Google Patents

Abstract

PURPOSE:To provide the method for forming films having a uniform thickness on a substrate surface by irradiating a material to be evaporated with high- density plasma. CONSTITUTION:A shielding material 24 having an electromagnetic wave absorbability of a value of murG larger than 10 when the specific dielectric constant is defined as G and the specific magnetic permeability as mur is installed between plural discharge plasma plasmas formed at the time of coating the surface of the substrate 15 with the films by providing a film forming chamber 6 with plural sets of evaporating means each consisting of a plasma gun 2 for forming discharge plasma flow 13, a hearth 7 to be packed with the raw material to be evaporated and a magnetic field for converging the discharge plasma flow and making this flow incident on the inside of this hearth in such a manner that the respective discharge plasmas are invisible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a film having a uniform thickness on a substrate having a large area by using an arc discharge plasma obtained by a discharge plasma generating means such as a composite cathode type plasma gun. The present invention relates to a method suitable for forming a transparent conductive film having resistance.

[0002]

2. Description of the Related Art Conventionally, as a method of coating a transparent conductive film of indium oxide with tin added to a substrate in a depressurized container, a vacuum vapor deposition method, a sputtering method, etc. have been known. The temperature of the coated substrate is 30
Below 0 ° C., it was difficult to coat a transparent conductive film having a low resistivity of 2 × 10 ⁻⁴ Ωcm or less.
As a method of coating the transparent conductive film having a low resistivity when the temperature of the substrate is 300 ° C. or lower, JP-A-2-22846.
No. 9 discloses a method in which plasma generated from a composite cathode type plasma is converged on a vapor deposition material in a hearth and the vapor is heated and evaporated. Further, as a method for uniformly coating a large-area substrate with a film, a method in which a plurality of plasma guns and the same number of hearths are installed is disclosed in JP-A-1-27.
It is disclosed in Japanese Patent No. 9748.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the method of coating a film by using one set of evaporation means consisting of an arc discharge plasma gun and a hearth disclosed in No. 9, since the spread of the evaporation flow from the hearth is limited, it is uniform over the entire surface of the substrate having a large area. There is a problem that it is difficult to coat such a film. On the other hand, in the method using a plurality of sets of evaporation means disclosed in Japanese Patent Laid-Open No. 1-279748, each plasma is disturbed by mutual interference of the generated plasmas, so that each plasma is arbitrarily converged to each hearth. It was difficult to create a state. Therefore, it is difficult to uniformly form a film on a large-area substrate.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem of mutual interference of a plurality of plasmas, and an arc discharge plasma flow by a gas containing an inert gas as a main component is provided. Evaporation means for generating and condensing the arc discharge plasma onto the vapor deposition material filled in the hearth placed below the arc discharge plasma flow by the magnetic field means to vaporize the vapor deposition material, a reduced pressure atmosphere A method of forming a coating film, wherein a plurality of vapor deposition raw materials vaporized from the plurality of hearths are applied to a surface of a substrate placed above the plurality of hearths, the plurality of discharge plasmas being provided. A shield is installed so that one discharge plasma stream cannot see the other discharge plasma stream, and the shield absorbs electromagnetic waves at a frequency of 150 Hz. a method for forming a coating, characterized in that the mu _r G 100 or more. Here, G is the relative conductivity of the shield to copper, and μ _r is the relative permeability of the shield.

[0005]

When a plurality of high-density plasma flows are simultaneously generated in one container, the plasma flows are affected by the self-induced magnetic field formed by the high-density plasma flows, and the convergence position to be converged in the hearth is Since it is off the center, the evaporation amount of the evaporation raw material from each hearth and the distribution in the evaporation direction are different, and the evaporation from each hearth cannot be the same. In the present invention, a shield having a large electromagnetic wave absorption capacity μ _r G is installed so that the arc discharge plasmas cannot be seen from each other among the plurality of high-density arc discharge plasma flows, so that each plasma flow forms. There is no mutual interference of plasma flows due to self-induced magnetic fields. Thereby, the turbulence of the plasma is suppressed, and the evaporation amount and the evaporation direction from each hearth can be made the same.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a film forming apparatus used for forming an ITO transparent conductive film on a substrate according to the present invention. The arc discharge plasma consists of an arc discharge plasma source 2 and a permanent magnet 8 on the bottom.
It is generated by performing an arc discharge with the DC power source 5 for plasma generation between the hearth 7 and the vapor deposition raw material which has the above and acts as an anode. The arc discharge plasma generation source 2 is preferably a composite cathode type plasma generator, a pressure gradient type plasma generator, or a plasma generator in which both are combined. Such a plasma generator is described in Vacuum No. 25, No. 10 (1
982). For example, a device as shown in FIG. The composite cathode type plasma generator includes an auxiliary cathode 17 having a small heat capacity and lanthanum boride (La).
And a main cathode 18 made of a B _6), to concentrate initial discharge to the auxiliary cathode, by using it to heat the main cathode LaB _6, the main cathode LaB ₆ is to perform the arc discharge as the final cathode It is a plasma generator. Examples of the auxiliary cathode include pipe-shaped ones made of a refractory metal such as W, Ta and Mo. The main cathode 18 is provided in contact with the cylinder 19, and the auxiliary cathode 17 is held via a disc-shaped heat shield 22. A disk 2 made of tungsten W is provided at the tip of the cylinder 19.
3 is provided. A gas for plasma generation is introduced from a discharge gas introduction port 21 provided at the center of the cathode support 20 provided with a water cooling mechanism, and the gas passes through the opening of the disk 23 and inside the film formation chamber 6. To the outside of the film forming chamber 6 through the exhaust port 9 by the exhaust pump. Further, the pressure gradient type plasma generator is a device in which an intermediate electrode is interposed between a cathode and an anode, and the discharge is performed while maintaining the cathode region at about 1 torr and the anode region at about 10 ⁻³ torr.
There is no damage to the cathode due to the backflow of ions from the anode region, and the gas efficiency of the carrier gas for creating a discharge electron flow is dramatically higher than that of the discharge type without an intermediate electrode, and a large current discharge is achieved. Has the advantage that The composite cathode type plasma generator and the pressure gradient type plasma generator have the above-mentioned advantages, respectively.A plasma generator combining the two, that is, a composite cathode is used as a cathode and an intermediate electrode is also arranged. The plasma generator described above is preferable as the arc discharge plasma generation source of the present invention because it can obtain the above advantages at the same time.

A cross-sectional view of the film forming apparatus used in the present invention is shown in FIG. Plasma source 2 as discharge cathode, permanent magnet 3
A first intermediate electrode 11 having a built-in magnetic field, a second intermediate electrode 12 having a magnetic coil 4 built-in, and a large-diameter magnetic coil 14 are provided on the side wall of the film forming chamber 6, and a permanent magnet 8 is provided below the film forming chamber. A hearth 7 was provided, and a set of these was used as one vapor deposition means. The hearth 7 acts as an anode of the discharge plasma 13 and the plasma generation source 2 acts as a cathode. Two high-density plasma streams 13 were formed by arranging the two vapor deposition means in parallel in the direction perpendicular to the paper surface of FIG. In order to guide the two discharge plasma flows 13 drawn into the film forming chamber 6 by the horizontal magnetic field formed by the magnetic coil 4 into the hearth filled with the vapor deposition material, the permanent magnets 8 provided at the bottom of the hearth 7 The vertical magnetic field bends the film forming chamber 6 downward at about 90 °. A substrate heating mechanism 16 is provided on the back surface of the substrate 15.
Is provided.

In order to suppress the turbulence of the plasma due to the mutual interference of the two high-density plasma flows drawn into the film forming chamber 6 from the two plasma generation sources, as shown in FIG. 1 and FIG. Is G and the relative magnetic permeability is μ _r, and the frequency of 150 Hz is such that the value of μ _r G is greater than 100, the shield 24 having an electromagnetic wave absorption capability is so that one plasma flow cannot see the other plasma flow. To install. Materials for such shields include iron and steel (SA
E1045), permalloy, mew metal, hypernic, etc. can be used.

Example 1 The inside of the film forming chamber 6 was set to 2 × 10 ⁻⁵ Tor by a vacuum exhaust pump.
After evacuating to a pressure of r, while the glass substrate 15 was heated to 200 ° C., about 30 sccm of argon (Ar) gas was introduced as a discharge gas from the discharge gas introduction pipe 1 and 2
A current of 100 A was supplied to each of the two plasma generators, and two arc discharge plasmas were generated between the hearth 7 and the two electrodes composed of the permanent magnet 8. As shown in FIG. 1, the plasma flow is 20c from the plasma source side.
It was provided at a distance of m (a position 35 cm above the bottom surface of the film forming chamber). As shown in FIG. 3, in order to suppress the turbulence of the plasma due to the mutual interference of the plasma flows, the length of the substrate in the traveling direction is 30 cm, the length in the height direction is 40 cm, and the thickness is 6 m.
An iron plate 24 having a value of μ _r G of 170 was set. In addition,
During film formation, oxygen gas is supplied from the reactive gas inlet 10 for about 50 s.
ccm was introduced. Substrate 15 is 10 cm square and 1.1 m thick
Seven glass substrates of m were arranged side by side in a direction perpendicular to the substrate traveling direction of FIG. Then, the substrate was moved in the direction shown in FIG. 3 at a constant speed to form an ITO film.
Further, the film thickness and the specific resistance of the obtained ITO film were measured at regular intervals with the left end of the glass substrate at the left end in FIG. 3 as the zero position.

FIGS. 4 (a) and 4 (b) show the film thickness distribution and the resistivity distribution of the ITO film obtained by the above method, respectively. The film thickness distribution within ± 5% can be obtained by 53c at a position 70 cm from the position 17 cm from the left end of the substrate.
It was found to be in the range of m. 1.5 × 10 ^-4 Ω ・ c
It was found that the range where the resistivity of m or more and 3.0 × 10 ⁻⁴ Ω · cm or less was obtained was between 38 cm at the position of 26 cm to 64 cm from the left end of the substrate. Therefore, the film thickness is within ± 5% and the resistivity is 1.5 × 10 ⁻⁴ Ω · c.
The range in which the ITO film having a thickness of m or more and 3.0 × 10 ⁻⁴ Ω · cm or less can be formed is 64 cm from the position 26 cm from the left end of the substrate.
It was found to be within the range of 38 cm up to the position. Since there was no film thickness or resistivity distribution in the substrate traveling direction, when a shield was installed, the film thickness was within ± 5% and the resistivity was 1.5 × 10 ^{−4 on} a substrate with a side of 38 cm. Ω · cm
More than 3.0 × 10 ⁻⁴ Ω · cm and less uniform and homogeneous I
A TO film can be formed.

Comparative Example 1 An ITO film was formed in the same manner as in Example 1 except that the shield provided in Example 1 was removed. The film thickness distribution and the resistivity distribution of the obtained film are shown in FIGS. 5 (a) and 5 (b), respectively. As in Example 1, the film thickness is within ± 5%,
And resistivity of 1.5 × 10 ^-4 Ω · cm or more 3.0 × 10 ^-4
It was found that the range in which the ITO film of Ω · cm or less can be formed is 17 cm from the position 26 cm to 43 cm from the left side of the substrate. Therefore, the film thickness is within ± 5% and the resistivity is 1.
An ITO film having a film thickness of 5 × 10 ⁻⁴ Ω · cm or more and 3.0 × 10 ⁻⁴ Ω · cm or less can be formed, which is a substrate capable of forming a uniform film as compared with Example 1. Means that the area of has become smaller.

Comparative Example 2 In comparison with Example 1, the shielding material was SUS304 (the value of μ _r G was 2).
The ITO film was formed in the same manner except that the material of (0) was changed. The film thickness distribution and the resistivity distribution of the obtained film are shown in FIGS. 6 (a) and 6 (b), respectively. Film thickness within ± 5% and resistivity of 1.5 × 10 ⁻⁴ Ω · cm or more 3.0 × 1
The range in which the ITO film of 0 ^-4 Ω · cm or less can be formed is 23 cm from the position 20 cm to the position 43 cm from the left side of the substrate.
It was found to be in the range. Therefore, when a metal plate with a small value of μ _r G is installed between the discharge plasma flows,
Substrate with a side of 23 cm or less, film thickness within ± 5% and resistivity of 1.5 × 10 ⁻⁴ Ω · cm or more and 3.0 × 10 ⁻⁴ Ω · cm
The following ITO film can be formed. This means that the area of the substrate on which a uniform film can be formed is smaller than that in the first embodiment.

[0013]

According to the present invention, a substrate having a larger area can be coated with a uniform film thickness. Also, ITO
When forming a film, a film having a good resistivity distribution can be applied to a substrate having a larger area.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a film forming apparatus used for implementing the present invention.

FIG. 2 is a cross-sectional view of an example of a discharge plasma generation source used in the present invention.

FIG. 3 is a partial plan view of a film forming apparatus used in the present invention.

FIG. 4 is a diagram showing a film thickness distribution and a resistivity distribution of the coating film obtained in Example 1.

5 is a diagram showing a film thickness distribution and a resistivity distribution of the coating film obtained in Comparative Example 1. FIG.

FIG. 6 is a diagram showing a film thickness distribution and a resistance distribution of a film obtained in Comparative Example 2.

[Explanation of symbols]

1 ... Discharge gas inlet, 2 ... Plasma source, 3 ... Permanent magnet, 4 ... Magnetic coil, 5 ... Discharge power source, 6 ... .... Deposition chamber, 7.
.... Hearth, 8 ... Permanent magnet, 9 ...
Exhaust pump, 10 ... Reactive gas inlet, 11 ...
.... First intermediate electrode, 12 ... Second intermediate electrode, 13 ...
... Plasma flow, 14 ... Large-diameter magnetic coil, 1
5 ... Base, 16 ... Base heating mechanism, 17 ...
..Auxiliary cathode of Ta pipe, 18 ... LaB ₆ main cathode, 19 ... Cylinder made of Mo, 20 ... Cathode support made of stainless steel, 21 ... Discharge gas inlet, 22 ··· Disc-shaped heat shield made of Mo, 2
3 ··· Disc made of W for protecting cathode, 24
.... Shielding

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoto Horiguchi 3-5-11 Doshomachi, Chuo-ku, Osaka City, Osaka Prefecture Nippon Sheet Glass Co., Ltd.

Claims (1)

[Claims] 1. An arc discharge plasma flow is generated by a gas containing an inert gas as a main component, and the arc discharge plasma is magnetically applied onto a vapor deposition material filled in a hearth placed below the arc discharge plasma flow. A plurality of evaporation means for converging and evaporating the vapor deposition raw material by means are installed in a container in which a depressurized atmosphere can be adjusted, and vapor deposition raw materials evaporated from the plurality of hearths are provided on the surface of the substrate. In the method for forming a coating film to be deposited on, a shield is installed between the plurality of discharge plasma streams so that one discharge plasma stream cannot see another discharge plasma stream, and the shield has a frequency of A method for forming a coating film, which has an electromagnetic wave absorption capability μ _r G at 150 Hz of 100 or more. Here, G and μ _r are the relative conductivity and relative permeability of the shield to copper, respectively.