JPH10140344A - Formation of conductive thin film to organic thin-film surface and organic el element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique to obtain an EL element having good characteristics and long life. SOLUTION: At the time of providing the inside of a vacuum chamber with a coil 7 internally arranged with a target 9 consisting of a cathode electrode film material and forming a cathode electrode film 14 thereof on the surface of an org. thin film 13 on a substrate 3 by the sputtering method, the distance (d) between the top end of this coil 7 and the substrate 3 is set at >=200mm and the frequency of the AC voltage to be impressed on the coil 7 is set at a range of 13.56 to 100MHz. Since electrons and ions are no longer made incident on the substrate, the damage to the org. thin film 13 may be lessened. At the initial period of the formation of the cathode electrode film 14, the pressure in the vacuum chamber is set at a pressure below 1.33×10<-2> Pa to lessen the damage to the boundary between the cathode electrode film 14 and the org. thin film 13. The film forming speed is improved if the amt. of the sputtering gas to be introduced is increased when the cathode electrode film 14 is formed to 20 to 50Å.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the technical field of organic EL devices, and more particularly to a technique for forming a conductive thin film on the surface of an organic thin film.

[0002]

2. Description of the Related Art In recent years, a display device using a high-luminance organic EL element which does not have a problem of a viewing angle has been attracting attention. Is being done.

In an organic EL device, a transparent conductive film formed on a glass substrate is used as an anode electrode film, a laminated organic thin film is formed on the surface thereof, and a conductive film serving as a cathode electrode film is formed on the organic thin film surface. A thin film is formed, and a voltage is applied between the transparent conductive film and the conductive thin film to cause the organic thin film to emit light.

[0004] In general, the formation of a conductive thin film involves the steps shown in FIG.
Is used, a target 209 made of a conductive thin film material is placed on a target holder 213, and a substrate 206 on which a film is to be formed is placed so as to face the target 209. A sputtering gas is introduced into the tank 205, and a DC voltage or an RF voltage is applied between the target holder 213 and the substrate 206 to generate a plasma 201 and generate a target 2.
09 is performed.

In such a parallel plate type sputtering apparatus, a magnetron magnet on the back side of the target holder 213 is arranged to increase the density of the plasma 201 on the surface of the target 209, but the plasma 201 is stably maintained. In order to perform, the inside of the vacuum
Usually, the pressure is maintained at 65 × 10 ⁻¹ Pa (5.0 × 10 ⁻³ Torr) or more.
Must be brought close to each other to a distance of about 10 cm, which is equal to or less than the mean free path.

Accordingly, the surface of the substrate 206 is
1 and the amount of electrons and ions incident on the substrate 206 is large, so that a cathode electrode film (conductive thin film) is formed on the surface of the organic thin film.
When the organic thin film is formed, the surface of the organic thin film is damaged, thereby deteriorating the characteristics of the EL element and shortening the life. The application of a vapor deposition apparatus using an EB gun to form the cathode electrode film was studied, but the electron beam damaged the organic thin film, and had the same problem as the sputtering apparatus.

Therefore, measures have been taken in the prior art,
At present, a specially-developed vapor deposition apparatus is used for manufacturing an EL element. As a cathode electrode film formed on an organic thin film, an MgAg film, a MgZn film, a LiAl film, and the like are known. A vapor deposition apparatus for forming an MgAg film will be described with reference to FIG.

The vapor deposition apparatus has a vacuum chamber 105, an evaporation source 110 for Mg, and an evaporation source 120 for Ag.
The inside of the vacuum chamber 105 is configured to be evacuated by a vacuum pump (not shown).

Each of the evaporation sources 110 and 120 is provided on the bottom wall of the vacuum chamber 105, and a substrate holder (not shown) is disposed on the ceiling of the vacuum chamber 105. When holding 106, the substrate 10
The six surfaces are configured to face the evaporation source 110 for Mg and the evaporation source 120 for Ag.

The Mg evaporation source 110 has a sealed container 113 containing a Mg material 111 and a heater 114 disposed in the sealed container 113, while the Ag evaporation source 120 has a filament 124. , And the Ag material 121 contained in the filament 124.

Since the Mg material 111 is sublimable, when the heater 114 is energized to generate heat, it evaporates without becoming a liquid, and the inside of the closed container 113 is filled with Mg vapor. A hole 115 having a diameter of 1 mm is provided at the upper part of the closed vessel 113, and the Mg vapor filled in the closed vessel 113 is discharged from the hole 115 into the vacuum chamber 105, and reaches the surface of the substrate 106 when it reaches the surface. Adhere to.

At this time, the filament 124 of the Ag evaporation source 120 is also energized to melt and evaporate the Ag material 121 to generate Ag vapor. The Ag vapor reaches the surface of the substrate 106 together with the Mg vapor. As a result, a cathode electrode film made of a MgAg film is formed on the surface of the substrate 106.

As described above, since the Mg vapor and the Ag vapor are separately generated, the Mg evaporation source 110 and the Ag evaporation source 12 are used.
A shielding plate 136 is provided between the evaporating sources and the evaporating sources so that the evaporation sources do not contaminate each other.

However, in recent years, a large-diameter EL display device has been required, and the substrate 106 on which the cathode electrode film is formed has also been increased in diameter. Hole 11 as described above
In the case where the cathode electrode film is formed by using the vapor released from 5, the film thickness distribution in the surface of the substrate 106 is poor.

Further, the cathode electrode film needs to be formed with a certain range of composition. For example, when the MgAg film is used as the cathode electrode film, the MgAg ratio is 10: 1 (= Mg:
Ag), but if it is attempted to form a cathode electrode film having a constant composition ratio on the surface of a large-diameter substrate, the above-described Mg evaporation source 110 and Ag evaporation source 120 will cause variations in the composition ratio within the substrate surface. Is not practical.

[0016]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages of the prior art, and its object is to provide an in-plane film thickness distribution and an in-plane composition without damaging an organic thin film. It is to form a conductive thin film having a good ratio distribution.

[0017]

According to a first aspect of the present invention, a substrate having an organic thin film formed on a surface and a target are placed in a vacuum chamber, and the target surface is sputtered. A method for forming a conductive thin film on an organic thin film surface by forming a conductive thin film on an organic thin film surface, comprising placing a target in a coil provided in a vacuum chamber, introducing a sputtering gas into the vacuum chamber, When configured so that the target surface can be sputtered when an AC voltage is applied, the upper end of the coil is positioned closer to the substrate than the target surface, and the distance between the substrate surface and the upper end of the coil is 200 mm or more. The frequency of the AC voltage applied to the coil is 13.56 MHz or more and 100 MHz or less.

In such a configuration, the conductive thin film material constituting the target is emitted from a wide area by sputtering on the surface of the target, so that a thin film can be formed uniformly on a large-diameter substrate.

Furthermore, the distance between the substrate surface and the upper end of the coil is increased to 200 mm or more, and the frequency of the AC voltage applied to the coil is set to a high frequency of 13.56 MHz or more and 100 MHz or less. It can be prevented from stopping and entering the substrate side. Therefore, the organic thin film formed on the surface of the substrate is not damaged, and can provide an EL element having good characteristics and a long life.

In the method of forming a conductive thin film on the surface of an organic thin film according to the present invention, a magnet is arranged on the back surface of the target so as to increase the plasma density near the target surface. Then, the formation speed of the conductive thin film is increased, and damage to the surface of the organic thin film can be further reduced.

Further, any one of claims 1 and 2
In the method of forming a conductive thin film on the surface of an organic thin film according to the above item, the pressure in the vacuum chamber is set to 1.33 × 1 in the initial stage of forming the conductive thin film on the surface of the organic thin film.
When the value is 0 ^-2 Pa or less, the number of electrons and ions incident on the substrate side when the interface between the organic thin film and the conductive thin film is formed is reduced, so that an EL device having better characteristics and a long life can be obtained. Can be.

However, the pressure in the vacuum chamber is set to 1.33 × 10 ^-2.
If the pressure is maintained at Pa, the growth rate of the conductive thin film is low, and the productivity is poor. In this case, after the formation of the conductive thin film is started, when the conductive thin film has a film thickness capable of protecting the interface, the initial state of low pressure formation is changed. It is preferable to end the process, increase the flow rate of the sputtering gas introduced into the vacuum chamber to increase the pressure in the vacuum chamber, increase the plasma density on the target surface, and increase the sputtering amount.

The thickness of the cathode electrode film as a guide for ending the initial state of formation is about 20 ° to 50 °.
As a guide for increasing the flow rate of the sputtering gas, the pressure in the vacuum chamber may be set to a normal sputtering pressure of 6.65 × 10 ⁻¹ Pa or more.

As one of the causes of the deterioration of the characteristics of the EL element and the shortening of the life thereof, there is a diffusion of the constituent material of the conductive thin film into the organic thin film. It has been found that diffusion tends to occur when the temperature of the organic thin film or the conductive thin film is increased while forming the conductive thin film on the surface of the organic thin film. Therefore, in the fifth aspect of the present invention, while the conductive thin film is formed, the temperature of the substrate is kept at 80 ° C. or less to prevent diffusion.

As a material for a cathode electrode film of an EL element,
Attention has been paid to the MgAg film.
In the case where the MgAg film is formed as a conductive thin film on the surface of the organic thin film by using the method for forming a conductive thin film on the surface of the organic thin film according to any one of claims 5 to 5, as in the invention according to claim 6, Alternatively, the target can contain magnesium and silver, and an MgAg film can be formed on the organic thin film.

After the organic thin film is formed, if the substrate is carried into a vacuum chamber without exposing the substrate to the atmosphere to form a conductive thin film, the state of the interface between the organic thin film and the conductive thin film is changed. As a result, the characteristics and life of the EL element are improved.

In any case, for an organic EL device having an organic thin film and a cathode electrode film formed on the organic thin film, the first conductive thin film having the cathode electrode film formed on the surface of the organic thin film, In the case where the first conductive thin film is formed with the second conductive thin film formed on the first conductive thin film, the first conductive thin film is formed so as not to damage the interface with the organic thin film, and the second conductive thin film is formed. When the conductive thin film is formed at a higher deposition rate than the first conductive thin film, it is possible to obtain an organic EL device having no deterioration in characteristics and a long life.

[0028]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an EL device manufacturing apparatus, which includes a pretreatment device 31, an organic thin film forming device 32, and a sputtering device 33. Each device 31
33 have vacuum tanks 80, 90, and 30, respectively, and are configured to be individually evacuated by a vacuum pump (not shown). Substrate holders 85, 95, and 15 are provided on the ceiling of each of the vacuum chambers 80, 90, and 30, respectively, and are configured to hold a plate-like substrate.

Using this EL device manufacturing apparatus, an anode electrode film 11 made of a transparent ITO film (indium tin oxide) as shown in FIG. 3A is formed on a glass substrate 10 in advance. The case where an organic thin film and a cathode electrode film (conductive thin film) are formed on a substrate will be described.

First, the substrate is carried into the vacuum chamber 80 of the pretreatment device 31 and is held by the substrate holder 85. At this time, the glass substrate 10 of the substrate is brought into close contact with the substrate holder 85, and the anode electrode film 11 faces the bottom wall of the vacuum chamber 80.

The substrate holder 85 on the bottom wall of the vacuum chamber 80
A radical gun 81 is provided at a position opposite to the above, a shutter 86 is provided between the radical gun 81 and the substrate holder 15, and the inside of the vacuum chamber 80 is evacuated and the shutter 86 is closed. In this state, the radical gun 81 is activated, and the radical gun 81
Radical ions are emitted within zero. In this state, the shutter 86 is opened, and the surface of the anode electrode film 11 is irradiated with radical ions to clean the anode electrode film 11.

The cleaned substrate is placed in a vacuum chamber 8.
From 0 to the vacuum chamber 90 of the organic thin film forming apparatus 32,
The substrate is held by a substrate holder 95 in a vacuum chamber 90.

On the bottom wall of the vacuum chamber 90, a first evaporation source 91 containing the first layer organic thin film material and a second evaporation source 92 containing the second layer organic thin film material are provided. The shutter 96 is provided between the first and second evaporation sources 91 and 92 and the substrate holder 95.

The shutter 96 and the shutters provided in the first and second evaporation sources 91 and 92 are closed, and the heaters in the first and second evaporation sources 91 and 92 are energized to close the shutter. The evaporation of the first and second organic thin film materials is started.

On the substrate holder 95, the cleaned anode electrode film 11 of the substrate is directed to the first and second evaporation sources 91 and 92. The shutter in the evaporation source 91 is opened first, and when the evaporation state of the organic thin film material is stabilized, the shutter 96 is opened to allow the vapor of the first organic thin film material to reach the surface of the anode electrode film 11, Start growing the organic thin film of the eye. First evaporation source 91
Inside, as a first layer organic thin film material, the following chemical formula,

[0036]

Embedded image

A diamine polymer is formed on the anode electrode film 11 by the vapor as a first organic thin film 12 (FIG. 3).
(b)).

When the first organic thin film 12 has a predetermined thickness, the shutter in the first evaporation source 91 is closed,
The shutter in the second evaporation source 92 is opened, and the growth of the second organic thin film on the surface of the first organic thin film 12 is started. In the second evaporation source 92, as a second-layer organic thin film material, the following chemical formula:

[0039]

Embedded image

The sublimable Alq ³ [Tris (8-hydr
oxyquinoline) aluminum, sublimed], and the vapor causes the surface of the first organic thin film 12
A film in which Alq ³ is polymerized is formed as the second organic thin film 13 (FIG. 3C).

When the second organic thin film 13 is formed to a predetermined thickness, the shutter 16 in the vacuum chamber 30 and the second
The shutter in the evaporation source 92 is closed, and the operation of forming the organic thin film is completed.

Next, the first and second organic thin films 12,
The substrate 3 on which the cathode electrode film 13 is formed is transferred from the vacuum chamber 90 into the vacuum chamber 30 of the sputtering device 33 and is held by the substrate holder 15.

The substrate holder 15 on the bottom wall of the vacuum chamber 30
The helical cathode 2 is provided at a position facing the helical cathode 2, a shutter 16 is provided between the helical cathode 2 and the substrate holder 15, while a bias power supply 25 and a high-frequency power supply 26 are provided outside the vacuum chamber 30. And are arranged.

The helical cathode 2 has a coil 7, a target holder 23, a target 9 and a magnet 8, as shown in FIG.
Reference numeral 3 is connected to an electrode on the negative potential side of the bias power supply 25, and is configured so that the potential can be lower than that of the target holder 15. On the other hand, both ends of the coil 7 are
Are connected to two positive and negative electrodes, respectively.
It is configured such that an alternating current can be passed through it.

The target 9 is made of a conductive thin film material made of magnesium (Mg) and silver (Ag), which is formed into a flat plate. The back surface of the target 9 is fixed to a target holder 23. 23 are arranged in the coil 7.

The conductors forming the coil 7 are
Is wound around the target holder 23 in a non-contact state, and is arranged so that the surface of the target 9 and the central axis of the coil 7 are substantially orthogonal to each other. Therefore, in the opening of the coil 7, the target 9 is
The surface of the target 9 and the substrate 3 held by the substrate holder 15 are substantially parallel to each other.

The upper end of the coil 7 is located closer to the substrate 3 than the surface of the target 9.
The distance d between the upper end of the coil 7 and the surface of the substrate 3 is 200 m
m.

After the inside of the vacuum chamber 30 is evacuated to a high vacuum state, introduction of a sputtering gas composed of argon gas into the vacuum chamber 30 is started with the shutter 16 closed.

The pressure in the vacuum chamber 30 is 6.65 × 10 ⁻³ P
a (5.0 × 10 ⁻⁵ Torr) and then the bias power supply 2
5, the target 9 is set to a negative potential, the high-frequency power source 26 is started, and a 13.56 MHz high-frequency voltage is applied to the coil 7 to generate plasma on the surface of the target 9; (Argon ion) Ar ⁺ is incident on the surface of the target 9 and sputtering of the target 9 is started.

The substrate 3 has the second organic thin film 13 directed toward the helical coil 2. When the plasma is stabilized, the shutter 16 is opened, and the cathode electrode made of magnesium and silver is applied to the surface of the second organic thin film 13. The growth of the film (conductive thin film) starts.

The electric field E formed by the coil 7 is parallel to the direction connecting the target 9 and the substrate 3 (the direction of the center axis of the coil 7) near the upper end of the coil 7, and the direction thereof is changed every half cycle. Reverse to Therefore, the force applied to the electrons and ions also reverses every half cycle, but the voltage applied to the coil 7 has a high frequency, and the reverse is performed very quickly.

In this case, the electron e ⁻ near the upper end of the coil 7.
And the sputtering gas ions reciprocate in the central axis direction of the coil 7 and cannot enter the substrate 3 side. As described above, when a high-frequency voltage is applied to the coil 7, electrons e ⁻ and sputtering gas ions hardly enter the second organic thin film 13, and damage is reduced.

The magnet 8 is arranged on the back surface of the target holder 23, and a magnetic field is formed on the surface of the target 9 by the magnet 8. Electrons are confined near the target surface by the magnetic field, and the target 9
The plasma density near the surface is high, and the plasma density is low near the surface. Therefore, the generated plasma does not spread to the substrate 3, so that the second organic thin film 13 is not exposed to the plasma and is not damaged.

The deposition rate of the cathode electrode film 14 in the case of using the helical cathode 2 is previously determined in association with the sputtering gas pressure in the vacuum chamber 30.
It is assumed that the initial state is completed when the cathode electrode film is formed to a thickness of about 50 °, the flow rate of the introduced sputtering gas is increased, the plasma density on the surface of the target 9 is increased, and the film forming speed is increased. As an example, the vacuum chamber 3
0 is 6.55 × 1 which is a normal sputtering pressure.
0 ^-1 Pa (5.0 × 10 ^-3 Torr).

When the film forming speed increases, the temperature of the substrate 3 rises. However, the indium foil 19 is provided on the surface of the substrate holder 15, and the adhesion between the glass substrate 10 of the substrate 3 and the substrate holder 15 is improved. Is configured to increase. Therefore, the heat generated in the substrate 3 is efficiently transmitted from the glass substrate 10 to the substrate holder 19 side.

A first thin film formed by performing sputtering at a low pressure of 6.55 × 10 ⁻³ Pa so as not to damage an interface portion of the organic thin film;
The film quality is different from that of the second thin film formed at a high sputtering rate by increasing the sputtering pressure to ^-1 Pa.
Such a difference in film quality between the first thin film and the second thin film is as follows.
It can be detected by an analyzer such as an IR analyzer.

Since the cooling water is circulated in the substrate holder 15 so that the temperature does not rise, the transferred heat is quickly discharged, so that not only the initial formation of the cathode electrode film 14 but also the Even when the speed is increased, the temperature of the substrate 3 is kept from becoming 80 ° C. or more.

As described above, the cathode electrode film 14 is formed while the substrate 3 is cooled.
(FIG. 3D), the shutter 16 is closed, the bias power supply 25 and the high-frequency power supply 26 are stopped, and the substrate on which the cathode electrode film 14 is formed is carried out of the vacuum chamber 30.

The substrate has an anode electrode film 11, first and second organic thin films 12, 13 and a cathode electrode film 14 formed on a glass substrate 10 in that order. As shown in FIG. When the electrode film 14 is set at a negative potential and the anode electrode film 11 is set at a positive potential, the interface between the first and second organic thin films emits light, and radiated light 18 transmitted through the glass substrate 10 is observed.

The case where the distance d between the upper end of the coil and the surface of the substrate 3 is set to 200 mm has been described above.
It should just be larger than. However, if the distance d is increased, the growth rate of the cathode electrode film becomes slow. Therefore, it is considered that the limit is about 300 mm in the mass production process.

In the initial stage of forming the cathode electrode film (conductive thin film) on the surface of the organic thin film, it is preferable to reduce the amount of the sputtering gas introduced and to lower the pressure in the vacuum chamber 30. In the above example, the pressure in the vacuum chamber at the initial stage of forming the cathode electrode film was set to 6.65 × 10 ⁻³ Pa (5.0 × 10 ⁻⁵ Torr), but the interface between the organic thin film and the cathode electrode film was damaged. In order to keep the plasma stable without giving
^{0 -2 Pa (1.0 × 10 -} 4 Torr) may be a less pressure.

The cathode electrode film is formed at a low pressure as described above.
When it is formed to a thickness of about 0 ° to 50 °, the interface can be protected by the cathode electrode film itself. Therefore, after the cathode electrode film is formed up to the film thickness, the introduction amount of the sputtering gas is increased, the state is shifted from the low pressure state at the initial stage of the formation to the state of the normal sputtering pressure, and the growth rate of the cathode electrode film is increased. Good. To increase the film forming rate, 6.55 × 10 ^-1 Pa (5.0 × 10 ^-3 T)
Orr) pressure, but the invention is not limited to that pressure.

In the above example, the frequency of the AC voltage applied to the coil 7 is 13.56 MHz.
If the frequency is in the range of 3.56 MHz or more and 100 MHz or less, electrons and ions do not enter the substrate side, and the cathode electrode film can be formed on the surface without damaging the organic thin film.

Although the case where the MgAg film is used as the cathode film has been described above, the present invention is not limited to this. When a conductive protective film is provided on the surface of an organic thin film and a cathode film is formed on the surface, the present invention can be used for forming the conductive protective film. Further, the substrate is not limited to glass, but includes a film-like substrate.

The case where the present invention is applied to an organic EL device has been described above, but the present invention is not limited to this.
Conventionally, electronics centered on semiconductors have been directed to inorganic substances, but in recent years, electronics technology using functional organic thin films using organic compounds has attracted attention. Organic compounds are attracting attention because various reaction systems and characteristics can be used more than inorganic substances, and surface treatment can be performed with lower energy than inorganic substances.

On the other hand, elements using a functional thin film include EL
There are elements, piezoelectric sensor elements, pyroelectric sensor elements, etc., each of which has been converted from an inorganic thin film to an organic thin film, but the present invention is applicable to forming a conductive thin film on the organic thin film surface of those elements. Can be widely used.

[0067]

According to the present invention, a conductive thin film can be efficiently formed on a large-diameter substrate. Since electrons and ions do not enter the organic thin film surface, the organic thin film is not damaged. When the pressure at the initial stage of the formation of the cathode electrode film is reduced, no damage is applied to the interface with the organic thin film. After the initial stage of the formation, if the introduction amount of the sputtering gas is increased, the deposition rate of the conductive thin film can be increased. If the substrate temperature during the formation of the cathode electrode film is lowered, diffusion of the constituent material of the cathode electrode film into the organic thin film can be prevented.

As described above, according to the present invention,
An organic EL element having good characteristics and a long life can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an EL element manufacturing apparatus that can be used in the present invention.

FIG. 2 is a diagram illustrating a helical cathode that can be used in the present invention.

FIGS. 3A to 3D are views for explaining the steps of the present invention.

FIG. 4 is a diagram illustrating a state in which an EL element manufactured according to the present invention emits light.

FIG. 5A is a view showing a general parallel plate type sputtering apparatus. FIG. 5B is a view for explaining a conventional cathode electrode film forming method.

[Explanation of symbols]

3 ... substrate 7 ... coil 8 ... magnet 9 ...
Target 30: Vacuum tank d: Distance between upper end of coil and substrate surface

Claims (8)

[Claims] 1. A substrate having an organic thin film formed on its surface and a target are placed in a vacuum chamber, and the target surface is sputtered to form a conductive thin film on the organic thin film. A method for forming a thin film, comprising: placing the target in a coil provided in the vacuum chamber; introducing a sputtering gas into the vacuum chamber and applying an AC voltage to the coil so that the target surface can be sputtered. When configuring, the upper end of the coil is located closer to the substrate than the target surface, and the distance between the substrate surface and the upper end of the coil is 200 m.
m or more, and the frequency of the AC voltage applied to the coil is 13.56 M
A method for forming a conductive thin film on the surface of an organic thin film, wherein the frequency is not less than 100 MHz and not more than 100 MHz. 2. The method for forming a conductive thin film on the surface of an organic thin film according to claim 1, wherein a magnet is arranged on the back surface of the target to increase the plasma density near the surface of the target. 3. The pressure in the vacuum chamber is set to 1.33 × 10 ^{−2 at the} initial stage of forming the conductive thin film on the surface of the organic thin film.
The pressure is set to Pa or less.
The method for forming a conductive thin film on the surface of an organic thin film according to any one of the above items. 4. The conductive thin film according to claim 3, wherein the flow rate of the sputtering gas introduced into the vacuum chamber is increased after the initial state of forming the conductive thin film is completed. Forming method. 5. The method according to claim 1, wherein the temperature of the substrate is set to 80 ° C. or less during the formation of the conductive thin film. A method for forming a conductive thin film. 6. The method for forming a conductive thin film on an organic thin film surface according to claim 1, wherein the target contains magnesium and silver. 7. The organic thin film according to claim 1, wherein, after the organic thin film is formed, the substrate is carried into the vacuum chamber without being exposed to the atmosphere. A method for forming a conductive thin film on a surface. 8. An organic EL device having an organic thin film and a cathode electrode film formed on the organic thin film, wherein the cathode electrode film has a first conductive thin film formed on the surface of the organic thin film. A second conductive thin film formed on the first conductive thin film, wherein the first conductive thin film is formed so as not to damage an interface with the organic thin film; Wherein the conductive thin film is formed at a higher deposition rate than the first conductive thin film.