JP3406769B2 - Ion plating equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion plating apparatus in which vaporized material particles are irradiated with electrons to be ionized and the ionized particles are attached to a substrate.

[0002]

2. Description of the Related Art FIG. 1 shows a conventional ion plating apparatus, in which 1 is a vacuum chamber. In the lower part of the vacuum chamber 1, a crucible 2 is arranged, and a material to be evaporated 3 is put therein. Reference numeral 4 is a filament, 5 is a high-voltage power supply, and the electron beam E generated from this filament 4 is deflected by 270 ° by a magnet (not shown) and is irradiated on the material 3 to be evaporated in the crucible 2. On the upper part of the chamber 1, a substrate holder 6b to which a substrate 6a to which an ionized evaporation material is attached is attached is arranged. A reaction gas supply pipe 8 having a needle valve 7 is provided on the side of the chamber 1.

Further, the chamber 1 is provided with a plasma electron gun 9. The plasma electron gun 9 includes a hot cathode 10 made of a tungsten material, a discharge electrode 11, and a discharge electrode 1.
2, an annular DC coil 13, an argon gas supply pipe 15 having a needle valve 14, a hot cathode power source 16, a discharge stabilizing resistor 17, a discharge power source 18, and a discharge electrode load resistor 19. A direct-current or high-frequency power source 20 is provided between the substrate holder 6b and the evaporation source (crucible 2) at the ground potential, so that the ionized evaporated particles can be efficiently transferred to the substrate 6a.
I try to lead in the direction. 21 is the chamber 1
An exhaust pipe connected to an exhaust pump for exhausting the inside.

In the above structure, first, the inside of the chamber 1 and the inside of the plasma electron gun 9 are evacuated to 10 ^-5 Torr or less. After that, the needle valve 14 provided in the argon gas supply pipe 15 of the plasma electron gun 9 is gradually opened to introduce the argon gas into the electron gun 9. Then, the hot cathode power supply 16 is turned on, the hot cathode current is gradually increased to the hot cathode rated temperature, and electrons are emitted from the hot cathode 16. Next, when the discharge power supply 18 is turned on and a discharge voltage is applied between the discharge electrode 11 and the discharge electrode 12, an argon discharge is generated between both electrodes and a discharge current flows.

Electrons generated by this discharge collide with the argon gas molecules, ionize the argon gas molecules, and this ionization proceeds to generate electron-excited plasma P. In addition,
At this time, the flow rate of the argon gas and the discharge voltage are adjusted to values at which discharge according to Paschen's law is started. Further, the plasma P generated in the plasma electron gun 9 is prevented from diverging by the magnetic field generated by the annular DC coil 13, and is focused in the central direction.

The electrons generated in the plasma P go straight and are accelerated toward the inside of the vacuum chamber 1. In addition,
Although not shown, an acceleration electrode is provided between the discharge electrode 12 and the chamber 1 so that the electrons in the plasma P can be efficiently extracted. In the vacuum chamber 1,
The filament 4 is heated to emit electrons and the crucible 2
The material 3 to be evaporated therein is irradiated with electrons. The material 3 is heated and evaporated by irradiation with electrons.

The evaporated material collides with electrons from the plasma electron gun 9 in the vacuum chamber 1 and is ionized and activated to generate plasma. The ionized material in the plasma is attracted to the substrate 6a,
Ion plating is performed by attaching to a. If the reaction gas is supplied from the supply pipe 8 simultaneously with the evaporation of the material 3 in the crucible 2, a substance based on the reaction between the evaporation material and the reaction gas can be attached to the substrate. For example, when the evaporation material is silicon and the reaction gas is oxygen gas, silicon dioxide (SiO ₂ ) is ion-plated on the substrate.

[0008]

In the ion plating apparatus described above, a part of the electron beam from the plasma electron gun 9 collides with the wall of the chamber 1 at the earth potential and is absorbed to form high density plasma. Can not do it. Further, the inside of the chamber wall is in a clean state in the initial state, but as the ion plating is advanced, the vaporized substance adheres to the inside of the wall and is covered with the insulating film.
When an insulating film is formed on this wall, the inside of the chamber wall is charged, and as a result, the state of the plasma formed inside becomes unstable.

Further, in the above-described ion plating apparatus, the trajectory of the electron beam from the plasma electron gun 9 is not reproducible, and the distribution of plasma formed in the chamber 1 may be non-uniform. Then, there is a film-forming species having a low reactivity between the vaporized substance and the reactive gas, and in the case of such a film-forming species, the ion plating cannot be efficiently performed on the substrate.

The present invention has been made in view of the above points, and an object thereof is to generate a plasma with good reproducibility,
It is to realize an ion plating device capable of stably performing precise film formation.

[0011]

An ion plating apparatus according to the first aspect of the present invention comprises a chamber and a chamber.
-The inside of the chamber and the substrate holder installed on the top
And a vaporization source having an electron gun for heating the vapor deposition material, and an electron beam for ionizing the material vaporized from the vaporization source in the chamber. The plasma electron gun to be used and the evaporation source are provided above the evaporation source, and the evaporation state of the vapor deposition material is in the initial state and the stable state.
And a shutter plate that can be opened and closed ,
Evaporation source and shutter provided inside the chamber
The floating electrode, which includes the plate and surrounds the plasma generated in the chamber from directions other than the upper part, and the potential of the shutter plate are used to evaporate the vapor deposition material.
Ground potential in the initial and stable states of
And a means for switching to a floating potential .

In the ion plating apparatus according to the first aspect of the invention, the floating electrode is arranged so as to surround the plasma generated in the chamber, and the potential of the openable / closable shutter plate provided above the evaporation source is grounded. Switching between a potential and a floating potential.

In the ion plating apparatus according to the second aspect of the present invention, an electrode is provided close to the evaporation source, and the potential of the electrode is set to the initial state and the stable state of evaporation of the material to be evaporated.
At ground potential and floating potential respectively
It is characterized by being configured to switch to.

In the ion plating apparatus according to the second aspect of the present invention, the potential of the electrode provided close to the evaporation source is switched between the ground potential and the floating potential.
The ion plating device based on the invention of claim 3 is
The floating electrode is characterized in that it can be changed from the floating potential to the ground potential.

In the ion plating apparatus according to the third aspect of the invention, the potential of the floating electrode can be changed from the floating potential to the ground potential .

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described with reference to the drawings.
The embodiment will be described in detail. FIG. 2 shows an image based on the present invention.
1 shows an on-plating device, the conventional device of FIG.
The same numbers are given to the same parts as. In this example
The crucible 2 is mounted on the turntable 22.
Although it is not done, the motor installed outside the chamber 1
Therefore, it is configured to be rotated. Crucible 2
The evaporation material (eg SiO ₂) 3 is posted
The electron beam E from the filament 4
Is irradiated. In addition, it approaches the crucible 2 and charges up.
A protection electrode 23 is arranged.

FIG. 3 is a diagram schematically showing the arrangement of each component in the chamber 1. In the chamber 1, an evaporation source 25 composed of a combination of a crucible 2, a material 3 and an electron gun 24 having a filament is provided. 2 are provided, and the charge-up prevention electrode 23 is arranged between the two evaporation sources 25. The charge-up prevention electrode 23 is made of copper and is water-cooled although not shown.

In FIGS. 2 and 3, a cylindrical floating electrode 26 is arranged so as to surround the plasma generation region in the chamber 1. Floating electrode 26
Has the effect of confining the generated plasma in a certain region, and is attached to the wall of the chamber 1 via an insulator 27. In addition, vapor from the material on the crucible 2 can pass through the cylindrical floating electrode 26, and the electron beam from the plasma electron gun 9 can be directed to the center of the chamber 1. Openings are provided at several locations for efficient exhaustion.

The floating electrode 26 is grounded via a potential adjuster 28. In addition, the charge-up prevention electrode 23 is connected to the switch 30 via the potential adjuster 29.
It is connected to the. The switch 30 switches the potential of the electrode 23 between the ground potential and the floating potential.

A water-cooled shirt 31 is arranged above the crucible 2. Although not shown in detail, the shutter 31 is configured so that it can be rotated from the horizontal state to the vertical state in FIG. 2, and the vapor from the material 3 is stably generated in the initial state of the ion plating operation. If not, the evaporation material is shielded so as not to face the substrate 6 as shown in the figure, and when the evaporation of the material 3 becomes stable, it is rotated and removed from the upper portion of the crucible 2. The shutter 31 is connected to a switch 32, and the switch 32 switches the potential of the shutter 31 between a floating state and a ground potential. The operation of such a configuration will be described below.

First, the operation of ion plating on the substrate 6a is performed in the same manner as in the conventional device of FIG. In the initial state, the shutter 31 is closed and the potential of the shutter 31 is set to the ground potential by the switch 32. Further, the charge-up prevention electrode 23 is set to the ground potential by the switch 30.

In this state, the material 3 is melted by the electrons from the electron gun 24 (filament 4). At this time,
Since the shutter 31 is at the ground potential, the trajectory of electrons from the electron gun 24 (filament 4) becomes stable, and the material can be efficiently heated and evaporated.

On the other hand, the electrons in the plasma formed in the chamber 1 head toward the crucible 2, but the charge-up prevention electrode 23 is always set to the ground potential by the switch 30 when the shutter 31 is closed. There is.
As a result, some of the electrons from the plasma electron gun 9 flow into the charge-up prevention electrode 23. Therefore, the electrons from the plasma electron gun 9 collide with the electrode 23 and are discharged, and the surface of the crucible 2 is prevented from being charged up by the electrons in the plasma.

Further, the electron beam generated from the filament 4 collides with the material 3 to generate reflected electrons and secondary electrons from the material 3. These reflected electrons and secondary electrons are provided close to the crucible 2. The surface of the crucible 2 is not charged up because it goes to the electrode 23 of the ground potential.

As a result, it is possible to prevent a phenomenon in which a discharge is generated between the crucible 2 and another place and the crucible 2 evaporates. Therefore, the crucible material does not evaporate and is not mixed in the vapor of the film forming material, and a pure film can be formed. Further, it is also possible to prevent the plasma from being disturbed by the discharge between the crucible 2 and the other part and adversely affecting the stability of the film formation.

Next, when the heating of the material 3 progresses and the steam is stably generated, the shutter 31 is opened (it is set to the vertical state), and the evaporated material is moved upward in the vacuum chamber 1. Head in the direction. This vaporized material collides with the electron from the plasma electron gun 9 in the vacuum chamber 1, is ionized and activated, and plasma is generated.

The ionized material in this plasma is
It is attracted to the substrate 6a and adheres to the substrate 6a for ion plating. If the reaction gas is supplied from the supply pipe 8 simultaneously with the evaporation of the material 3 in the crucible 2, a substance based on the reaction between the evaporation material and the reaction gas can be attached to the substrate.

When ionizing the evaporation material, the switch 30 and the switch 32 are switched, and the charge-up prevention electrode 23 and the shutter 31 are set to the floating potential. As a result, the generated plasma is surrounded by the electrode 26 having a floating potential, the electrode 23, and the shutter 31.

The electrodes and the like of each floating potential have a negative potential (several 10 to 100 V) with respect to the ground due to the self-bias potential of plasma. As a result, the electrons emitted from the plasma electron gun 9 are confined in the vacuum chamber 1 and the electron density is increased.

Therefore, high-density plasma with good uniformity is generated in the chamber 1. On the other hand, evaporation source 2 for vapor deposition
Since 5 is at the ground potential, the electrons are concentrated in the evaporation source and the excited ionization of the evaporated material is promoted. Therefore, the evaporation material and the reactive gas can be turned into a high density plasma, the reactivity is improved, and a good quality film can be formed on the substrate 6a.

Here, the floating electrode 26 can change its floating potential from a plasma self-bias potential to a ground potential by a potential regulator 28. This is because when the potential difference between the substrate holder 6b or the substrate 6a and the floating electrode 26 is given depending on the film forming conditions to control the amount of ions taken into the substrate 6a.
When using an electrically weak substrate, it is effective to set the floating electrode 26 to the ground potential to reduce the energy of the ions toward the substrate 6a and prevent electrical damage to the substrate.

Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment. For example, the plasma electron gun of FIG. 2 can use a plasma electron gun other than the structure shown in FIG.

[0033]

As described above, in the ion plating apparatus according to the first aspect of the present invention, the floating electrode is arranged so as to surround the plasma generated in the chamber, and the opening / closing provided above the evaporation source. Since the potential of the possible shutter plate is configured to be switched between the ground potential and the floating potential, the electrons from the plasma electron gun are efficiently confined in the chamber, and the electron density is increased to achieve high density with good uniformity. Plasma is generated. As a result, plasma can be generated with good reproducibility, and high-quality film formation can be stably performed.

In the ion plating device according to the second aspect of the present invention, the potential of the electrode provided close to the evaporation source is switched between the ground potential and the floating potential. Electrons from the gun flow into this electrode and are effective in preventing charge-up of the crucible. Further, in the steady state where ion plating is performed, the electrodes are set to the floating potential, so that the plasma can be efficiently confined in the chamber.

In the ion plating apparatus according to the third aspect of the present invention, since the potential of the floating electrode can be changed from the floating potential to the ground potential, the amount of ions directed to the substrate can be controlled according to the film forming conditions. It will be possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a conventional ion plating apparatus.

FIG. 2 is a diagram showing an example of an ion plating apparatus according to the present invention.

3 is a plan view of a crucible and an earth electrode portion used in the embodiment of FIG.

[Explanation of symbols]

1 vacuum chamber 2 crucibles 3 Material to be evaporated 4 filament 6a substrate 8 Reaction gas supply pipe 9 Plasma electron gun 22 turntable 23 Charge-up prevention electrode 26 Floating electrode 27 Insulator 28,29 Potential regulator 30,32 switch 31 shutter

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-6-264227 (JP, A) JP-A-6-2166 (JP, A) JP-B-62-46630 (JP, B1) (58) Field (Int.Cl. ⁷ , DB name) C23C 14/00-14/58 H01J 37/32 H05H 1/24

Claims (3)

(57) [Claims] 1. A chamber and an upper part inside the chamber.
The mounted substrate holder and the lower part inside the chamber .
Is, an evaporation source having an electron gun for heating the deposited material, provided on the side of the chamber, the evaporated material from the evaporation source tea
Plasma electron gun that generates an electron beam for ionization in the chamber and the material to be vapor-deposited provided above the evaporation source.
Closed in the initial and stable states of evaporation of
And a shutter plate that can be opened and closed , and an evaporation source and a shutter plate that are provided inside the chamber and are inside.
In both cases, plasma generated in the chamber is not on top
Direction of the floating electrode and the potential of the shutter plate are set to the initial state of evaporation of the material to be evaporated.
Ground potential and flow in steady state and steady state, respectively
And an ion plating device provided with means for switching to a charging potential . 2. An electrode is provided close to an evaporation source, and the potential of the electrode is set to an initial state and a stable state of evaporation of a material to be evaporated.
Ground potential and floating
The ion plating device according to claim 1, wherein the ion plating device is configured to be switched to a position . 3. A floating electrode, according to claim 1 or was capable of changing the floating potential to the ground potential
Alternatively, the ion plating apparatus according to claim 2 .