JPH05295526A - Vapor deposition method and vapor deposition device - Google Patents

Abstract

PURPOSE:To form an excellent thin film at a high speed by rotating a hearth for a raw material for vapor deposition and a base body and introducing plasma flow to a specific position at the time of heating the raw material for vapor deposition by a plasma gun and forming the thin film of the raw material for vapor deposition on a substrate on an opposite side. CONSTITUTION:The raw material 3 for vapor deposition and the hearth 4 holding this raw material are disposed in a vapor deposition chamber 10 and the substrate 6 is placed in the position opposite thereto. The plasma gun 1 is set therebetween. A magnet 5 is disposed on the rear side of the hearth 4 in order to efficiently converge the plasma flow 9 emitted from the plasma gun 1 onto the hearth 4. The substrate 6 is heated by a heater 11 and the inside of the vapor deposition chamber 10 is evacuated to a reduced pressure. Gaseous Ar and O2 are introduced therein and the plasma flow 9 of a high density is generated by the plasma gun 1 to evaporate the raw material 3 for vapor deposition by the plasma flow 9, by that, the thin film of the raw material 3 for vapor deposition is formed on the surface of the substrate 6 moving in an arrow direction. The raw material hearth 4 and the substrate 6 are rotated around a nearly perpendicular axis of rotation, in this case, to introduce the plasma flow 9 to the position deviating from the axis of rotation of the substrate 6, by that, the raw material 3 for vapor deposition is uniformly evaporated and the vapor deposition efficiency is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor deposition method and a vapor deposition apparatus for forming a thin film.

[0002]

2. Description of the Related Art A high current, low voltage plasma gun is 100
It is possible to supply a high-current electron beam at a voltage as low as V,
Since the energy of the supplied electrons is as low as about 100 eV, the reaction gas and the vapor deposition material can be ionized and activated with high density.

That is, not only the vapor deposition material can be vaporized at high speed, but also highly reactive plasma of the vapor deposition material can be formed in the vaporization space, which has high performance even on a low temperature substrate and has excellent performances in various characteristics. The thin film can be formed at high speed (see Japanese Patent Laid-Open No. 240250/1990).

[0004]

However, when film formation is continued with the raw material hearth being fixed, the film formation batches including the film thickness (in this specification, "film formation batch" means a plasma gun power supply). (It means 1 film forming process from putting in the substrate, forming the film, and stopping the plasma gun power supply.) The thin film characteristics are relatively stable, but the effective use area of the raw material is not only small. There is no easy way to replenish the raw materials. That is, there is a drawback in that the number of continuous film forming batches is limited because it is necessary to stop the film forming to replenish the evaporation material and to open the evaporation space to the atmosphere.

On the other hand, it may be possible to simply move the raw material hearth in a translational manner, but this increases the effective use area of the raw material and facilitates the replenishment of the raw material, while the above problems can be solved. It has a drawback that the film forming rate and the thin film characteristics vary greatly between film batches.

That is, since the high current electron beam has a high electron density and the source hearth also functions as an anode for forming a high density plasma, if the source hearth is simply translated, an electron beam or The boundary conditions of the plasma will change significantly, and along with that, the characteristics and spatial distribution of the electron beam and plasma will also change greatly,
It has a drawback that the film forming speed and the thin film characteristics vary greatly. The object of the present invention is to eliminate the aforementioned drawbacks of the prior art.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, in which an evaporation source is heated by using a plasma gun capable of forming a plasma flow by generating an electron beam. , A vapor deposition method for forming a thin film on a substrate on the side opposite to a vapor deposition raw material with respect to a plasma flow, in which a raw material hearth holding the vapor deposition raw material is rotated around a rotation axis substantially vertical to the base, and the vapor source raw material hearth is rotated. To newly provide a vapor deposition method characterized by guiding a plasma flow to a position deviated from the rotation axis of.

The present invention also provides a plasma gun capable of forming a plasma flow by generating an electron beam, and a plasma flow generated by the plasma gun, which is substantially perpendicular to the substrate arranged on the side opposite to the position of the substrate on which the thin film is formed. A vapor deposition apparatus comprising: a raw material hearth that holds a vapor deposition raw material that is rotatable around a rotation axis; and a magnetic field forming unit that guides a plasma flow at a position deviated from the rotation axis of the raw material hearth. To do.

FIG. 1 (a) is a conceptual sectional view of an example of the vapor deposition apparatus of the present invention, and FIG. 1 (b) is a conceptual plan view of the vapor deposition chamber of the apparatus of FIG. 1 (a). Reference numeral 1 is a plasma gun, 3 is a vapor deposition raw material, 4 is a raw material hearth for holding the vapor deposition raw material 3 (hereinafter, also simply referred to as hearth), and 6 is a substrate for forming a thin film.

FIG. 2 is a perspective view (including a partial sectional view) for explaining the peripheral portion of the raw material hearth 4 in more detail. To the raw material hearth of the present invention, a discharge current is supplied from the atmosphere side of the vapor deposition chamber wall 45 by the current introduction terminal 47, and cooling water is supplied by the cooling water introduction pipe 46 and the hearth cooling water passage 44. The rotary driving force 48 of the hearth 4 is introduced by a rotary shaft 43 connected to a rotary driving motor (not shown), and is rotatable around the rotary shaft 41.
The rotating shaft 41 is used to form a thin film uniformly on the substrate.
It is preferably substantially perpendicular to the substrate or the plane containing the substrate.

The magnet 5 placed directly under the hearth 4 is one of magnetic field forming means for binding the electron beam from the plasma gun and forming the magnetic force line 14 that converges on the vapor deposition material 42. Are arranged so as to be in the vertical direction, and are installed at positions where electron beams can be irradiated to a position (electron beam spot 12) deviated from the rotation axis 41 of the hearth on the vapor deposition material 42. A plasma stream 9 is formed along such an electron beam.

As the method for rotating the hearth, a method of continuously or intermittently rotating the film at an arbitrary speed and a rotating direction during film formation, and a method of stopping the hearth during film formation and after completion of the film formation batch There is a method of rotating it by an arbitrary angle, and either method may be selected.

Most preferably, the shape of the hearth is circular in cross section perpendicular to the axis of rotation so that the relative position does not change with respect to the vapor deposition chamber wall and the electron beam during rotation. Further, it may be an external polygon having a pentagon shape or more. A quadrangle or a triangle may affect the stabilization of the plasma spatial distribution and the like.

The plasma gun 1 which is a source of the electron beam used in the present invention may be an arc discharge type plasma gun, a hollow cathode type plasma gun or the like as long as it can generate an electron beam. It is preferable to use an arc discharge type plasma gun 1 which can easily supply a high-density electron beam and thereby plasma.

The arc discharge type plasma gun 1 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", Vol. 25, No. 10 (published in 1982).

The composite cathode type plasma generator has an auxiliary cathode having a small heat capacity and a main cathode made of LaB ₆ ,
Concentrating the initial discharge to the auxiliary cathode is heated in a short time, by using it to heat the main cathode LaB _6, the main cathode LaB ₆
Is a plasma generator that performs arc discharge as the final cathode. For example, a device as shown in FIG.

The auxiliary cathode 52 may be a coil made of a refractory metal such as W, Ta or Mo, or a pipe-shaped one. Reference numeral 53 is a disk made of W or the like for protecting the cathode, 54 is a cylinder made of Mo or the like, 55 is a disk-shaped heat shield made of Mo or the like, 56 is cooling water, and 57 is a cathode support base made of stainless steel or the like. , 58 are gas inlets.

In such a compound cathode type plasma generator, the auxiliary cathode 52 having a small heat capacity is intensively heated by the initial discharge to operate as the initial cathode and indirectly La.
Before the auxiliary cathode 52 reaches a high temperature of 2500 ° C. or more and affects its life, it is a method of heating the B ₆ main cathode 51 and finally shifting to arc discharge by the LaB ₆ main cathode 51. The main cathode 51 of LaB ₆ is 1500 ° C ~
It is a great advantage that it is heated to 1800 ° C., a large electron beam can be emitted, and a further temperature rise of the auxiliary cathode 52 can be avoided.

The pressure gradient type plasma generator is
An intermediate electrode is interposed between the cathode and the anode, and the cathode area is several Ts.
The discharge is performed at about orr and the anode region is maintained at about 10 ^-3 Torr, and there is no damage to the cathode due to backflow of ions from the anode region. In addition, the gas efficiency of the carrier gas for producing the discharge electron beam is extremely high, and there is an advantage that a large current discharge is possible.

The composite cathode type plasma generator and the pressure gradient type plasma generator have the above-mentioned advantages, respectively, and a plasma generator in which both are combined, that is, a composite cathode is used as a cathode and an intermediate electrode is used. The plasma generator having the above arrangement is also preferable as the arc discharge plasma gun 1 of the present invention because it can obtain the above advantages at the same time.

The structure of the vapor deposition chamber 10 will be described below with reference to FIG. A magnetic field is formed in the axial direction of the plasma gun by the air-core coil 2 which is one of the magnetic field forming means, and the direction of the magnetic field formed at that time is the output direction of the gun. Further, the vapor deposition material 3 and the hearth 4 are arranged on the side opposite to the substrate 6 with the axis of the plasma gun 1 as the center. In addition, a magnet 5 is arranged immediately below the hearth 4 for the purpose of bending the electron beam and the plasma flow generated by the electron beam in the direction of the hearth 4, and a magnetic force line 14 is formed by the air-core coil 2 and the magnet 5, and an electron is generated along the magnetic force line. Bend the beam.

In this case, in order to efficiently focus the plasma flow emitted from the plasma gun 1 on the hearth, the magnet 5 is arranged so that the hearth side has the S pole and the side farther from the hearth has the N pole.
To place. Then, a voltage is applied from the plasma gun power source 7 to the plasma gun 1 so that the hearth 4 becomes an anode, and the vapor deposition material 3 is heated and vaporized in the electron beam spot 12 mainly in the plasma stream 9 by the electron beam.

The base 6 is arranged so as to face the hearth 4. At this time, the substrate may be heated by the heater 11 or the substrate bias power source 8 may apply a DC or RF substrate bias voltage. When performing the reactive deposition, the reaction gas 13 is introduced.

Further, as shown in FIG. 1, two or more sets of a plasma gun, a raw material hearth and a magnetic field forming means may be provided in parallel with each other so as to uniformly form a thin film on a larger substrate. In this case, the rotation directions of the plurality of raw material hearths are not particularly limited, but it is preferable to make the center of the substrate as symmetrical as possible for forming a uniform thin film.

[0025]

According to the present invention, extremely reactive plasma can be formed in the evaporation space, and a thin film having excellent characteristics can be formed at high speed even on a low temperature substrate. In addition to this, it is characterized in that the vapor deposition raw material can be effectively used and the raw material can be easily supplied without changing the film forming rate and the thin film characteristics.

In this apparatus, the hearth rotates around its rotation axis, and the electron beam is irradiated to a position on the vapor deposition material that is deviated from the rotation axis of the hearth. Therefore, the vapor deposition material is a donut along the rotation of the hearth. Is consumed in the form of. Therefore, not only is the effective use area of the raw material increased, the raw material filling frequency is reduced, but also the region 49 (raw material supply position) where the electron beam is not irradiated can be secured on the raw material hearth, so that it is possible during vapor deposition. Also, the vapor deposition material can be easily supplied to this region 49.

Further, the raw material hearth, which also functions as an anode for discharge, has a circular cross section perpendicular to the rotation axis and only rotates on the rotation axis. Its relative position with respect to the electron beam does not change. Therefore, there are no fluctuations in the boundary conditions that are particularly important for stabilizing the characteristics and spatial distribution of the high-current electron beam and the high-density plasma. As a result, it is possible to reduce variations in the film formation rate and thin film characteristics.

Further, by changing the rotation speed of the hearth, the film formation speed can be controlled independently of the control of the film formation speed by the plasma gun current. That is, if the film forming speed is changed only by the gun current, the plasma characteristics are also greatly changed, but by changing the rotation speed of the hearth with the gun current kept constant, The film formation rate can be controlled without changing the plasma characteristics.

The reason for this is that while the vapor deposition material is heated by the electron beam and is cooled by the hearth cooling water, increasing the rotation speed of the hearth shortens the net heating time, and as a result, It is considered that this is because the temperature of the vapor deposition material decreases and the evaporation rate of the material decreases.

[0030]

【Example】

(Embodiment 1) Tin was used as a vapor deposition raw material by using a vapor deposition apparatus as shown in FIG. 1 in which a composite cathode type and pressure gradient type plasma gun as shown in FIG. 3 and a rotary hearth as shown in FIG. 2 were arranged. A sintered body of indium oxide added at 5% by weight was crushed and used. As the substrate, non-alkali glass (AN glass manufactured by Asahi Glass) heated to 200 ° C. was used.

First, after evacuation of the vapor deposition chamber to 1 × 10 ^-5 Torr or less, a mixed gas of argon gas and oxygen gas is added.
It was introduced so that the gas pressure was 1 × 10 ⁻³ Torr, the discharge current by the plasma gun power source was fixed at 250 A, and high density plasma was generated. After that, the above glass substrate was conveyed at a conveying speed of 45 cm / min, and ITO having a film thickness of 2500 Å was conveyed.
A (indium-tin oxide) film was formed.

In FIGS. 4 and 5, when the hearth is stopped at a position of 0 degrees to form a film (□), after the film is formed, the hearth is stopped at a position rotated by 120 degrees from the position of 0 degrees to form a film. (+), The standardized film thickness distribution and standardized specific resistance distribution (hearth of 0 degrees after deposition) were stopped when the hearth was rotated 240 degrees from the 0 degree position to form the film (◇). The relative value with respect to the film thickness and the specific resistance at the position of is referred to as a normalized film thickness and a standardized specific resistance). Each measurement was performed within a range of 60 cm in the width direction perpendicular to the traveling direction of the substrate.

In addition to obtaining a thin film having a specific resistance value of 190 to 150 μΩcm and good electrical characteristics, FIG.
As shown in, the fluctuations in the film thickness distribution and the specific resistance distribution depending on the stop position of the hearth are less than half as compared with the comparative example described later. Therefore, it is understood that when the film is formed while rotating the hearth, not only the fluctuations in various characteristics in the traveling direction are small, but also the raw material is easily supplied during the film formation.

(Embodiment 2) A compound cathode type and pressure gradient type plasma gun as shown in FIG. 3 and a rotary hearth as shown in FIG. A sintered body of indium oxide containing 7.5% by weight was crushed and used. As the substrate, non-alkali glass (AN glass manufactured by Asahi Glass) heated to 200 ° C. was used.

First, the film forming chamber is evacuated to 1 × 10 ⁻⁵ Torr or less, and then a mixed gas of argon gas and oxygen gas is added.
The gas was introduced so that the gas pressure was 1 × 10 ⁻³ Torr, the discharge current was fixed at 250 A, and high density plasma was generated. Then, the glass substrate was conveyed at a conveying speed of 45 cm / min to form an ITO film.

FIG. 6 shows how the film forming speed changes with respect to the rotational speed of the hearth. FIG. 7 shows how the plasma density changes with the rotational speed of the hearth. The plasma density was measured using a Langmuir probe at the center of the vapor deposition region and at a position 10 cm below the substrate. As shown above, it can be seen that by increasing the rotation speed of the hearth, the film formation speed can be controlled without changing the plasma density.

(Embodiment 3) A compound cathode type plasma gun as shown in FIG. 3 and a pressure gradient type plasma gun and a rotary hearth as shown in FIG. A sintered body of indium oxide containing 7.5% by weight was crushed and used. As the substrate, non-alkali glass (AN glass manufactured by Asahi Glass) heated to 200 ° C. was used.

First, after evacuation of the film forming chamber to 1 × 10 ⁻⁵ Torr or less, a mixed gas of argon gas and oxygen gas is added.
It was introduced so that the gas pressure was 1 × 10 ⁻³ Torr, and the rotational speed of the rotary hearth was fixed at 0.1 rpm.
Next, the discharge current from the plasma gun power supply was fixed at 250 A, and high density plasma was generated. After that, the glass substrate is conveyed at a conveying speed of 45 cm / min, and a film thickness of 2500
An ITO film of Å was formed. The above film forming batch was performed 9 times.

8 and 9, the normalized film thickness distribution and the normalized specific resistance distribution in the substrate width direction between the film forming batches (the relative values for the film thickness and the specific resistance of the ninth batch are the normalized film thickness and the standard value). (Compared to specific resistance)). Each measurement was performed within a range of 60 cm in the width direction perpendicular to the traveling direction of the substrate. Also,
FIG. 10 shows a comparison of normalized film thickness distributions in the substrate traveling direction between film forming batches. The measurement was performed within a range of 60 cm in the traveling direction of the substrate.

In addition to obtaining a thin film having a specific resistance value of 180 to 160 μΩcm and good electrical characteristics, FIG.
As shown in FIG. 10 and FIG. 10, the fluctuations in the film thickness distribution and the resistivity distribution in the substrate width direction and the advancing direction cause the hearth to be described later to move in translation by forming the film while rotating the rotary hearth of the present invention. It can be improved to less than half as compared with the comparative example. Further, even during the film formation, it was very easy to supply the vapor deposition material to the portion of the hearth which was not irradiated with the electron beam.

(Comparative Example) Using a vapor deposition apparatus as shown in FIG. 1 in which a composite cathode type and pressure gradient type plasma gun as shown in FIG. 3 was arranged, tin was added in an amount of 7.5% by weight as a vapor deposition raw material. A sintered body of indium oxide was crushed and used. However, in this example, a rotary hearth as shown in FIG. 2 was not used, but a raw hearth capable of translational movement in a direction parallel to the traveling direction of the substrate was used. As the film formation substrate, non-alkali glass (AN glass manufactured by Asahi Glass) preheated to 200 ° C. was used.

First, the film forming chamber is evacuated to 1 × 10 ⁻⁵ Torr or less, and then a mixed gas of argon gas and oxygen gas is added.
The gas was introduced so that the gas pressure was 1 × 10 ⁻³ Torr, the discharge current was fixed at 250 A, and high density plasma was generated. Then, the glass substrate was conveyed at a conveying speed of 45 cm / min to form an ITO film having a film thickness of 2500 Å.

In FIGS. 11 and 12, when the hearth is stopped near the gun for film formation (□), when the hearth is stopped at the center position for film formation (+), the position opposite to the gun is shown. Normalized film thickness distribution and standardized resistivity distribution when film is stopped at (◇) (Relative values for film thickness and resistivity when hearth is located near the gun are standardized film thickness and standardization) The change in the specific resistance). Each measurement was performed within a range of 60 cm in the width direction perpendicular to the traveling direction of the substrate.

Although a thin film having a specific resistance value of 190 to 160 μΩcm and excellent electric characteristics can be obtained, as shown in FIGS. 11 and 12, the film thickness distribution and the specific resistance distribution fluctuate greatly depending on the stop position of the hearth. To do. In particular, when a film is formed while translating the hearth, this fluctuation appears as a large fluctuation in various characteristics in the traveling direction.

[0045]

INDUSTRIAL APPLICABILITY According to the present invention, in a vapor deposition apparatus having at least one set of plasma gun and raw material hearth, a thin film having high speed and excellent characteristics can be easily formed on a low temperature substrate, and the film forming speed and the thin film characteristics can be improved. Film formation without fluctuation of
Further, it has an excellent effect that the vapor deposition material can be effectively used and the material can be easily supplied. In particular, in an in-line type vapor deposition apparatus in which the vapor deposition container is not opened to the atmosphere between film forming batches, it is extremely difficult to use the hearth as in the present invention from the viewpoint of reducing the frequency of opening to the atmosphere for supplying the vapor deposition material. preferable.

Further, by combining two or more sets of plasma guns and hearths, it is possible to form a film on a large area of 1 m × 1 m or more without deteriorating thin film characteristics. Further, by changing the rotation speed of the hearth, independently of the control of the film forming speed by the gun current,
It also has the effect of controlling the film formation rate.

Particularly, in reactive vapor deposition of elements having low reactivity, a high-current electron beam is introduced to increase the plasma density, and then the rotational speed of the hearth is increased to reduce the vapor deposition rate of the raw material. This also has the effect of obtaining a compound thin film that is difficult to obtain by ordinary reactive vapor deposition.

[Brief description of drawings]

1A is a conceptual cross-sectional view of an example of a vapor deposition apparatus of the present invention, and FIG. 1B is a conceptual plan view of a vapor deposition chamber of the apparatus of FIG.

FIG. 2 is a perspective view (including a partial cross-sectional view) of the raw material hearth and its peripheral portion according to the present invention.

FIG. 3 is a sectional view of an example of an arc discharge type plasma gun used in the present invention.

FIG. 4 is a graph showing the film thickness distribution of the ITO film in Example 1.

FIG. 5 is a graph showing the resistivity distribution of the ITO film in Example 1.

FIG. 6 is a graph showing changes in the film formation rate with respect to the rotational speed of the hearth in Example 2.

FIG. 7 is a graph showing changes in plasma density with respect to the rotational speed of the hearth in Example 2.

FIG. 8 is a graph showing the film thickness distribution of the ITO film in the substrate width direction in Example 3.

FIG. 9 is a graph showing the resistivity distribution of the ITO film in the substrate width direction in Example 3.

FIG. 10 is a graph showing the film thickness distribution of the ITO film in the substrate traveling direction in Example 3.

FIG. 11 is a graph showing a film thickness distribution of an ITO film in a comparative example.

FIG. 12 is a graph showing a specific resistance distribution of an ITO film in a comparative example.

[Explanation of symbols]

1: Plasma gun 2: Air core coil 3: Evaporation raw material 4: Raw material hearth 5: Magnet 6: Substrate 7: Plasma gun power supply 8: Substrate bias power supply 9: Plasma flow 10: Deposition chamber 11: Heating heater 12: Electron beam spot 13: Reaction gas 14: Magnetic field lines formed by the magnetic field forming means 2 and 5 41: Hearth rotation axis 42: Vapor deposition material 43: Rotation shaft 44: Hearth cooling water passage 45: Vapor deposition chamber wall 46: Cooling water introduction pipe 47: Current introduction terminal 48: Rotational driving force 49: Raw material supply position 51: LaB ₆ main cathode 52: Auxiliary cathode 53: Disk made of W or the like for protecting the cathode 54: Cylinder made of Mo or the like 55: Made of Mo or the like Disc-shaped heat shield 56: Cooling water 57: Cathode support made of stainless steel 58: Gas inlet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Teruyuki Yagami 1160 Matsubara, Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa AZ Technology Co., Ltd. 1-chome Asahi Glass Co., Ltd. Keihin factory

Claims (6)

[Claims] 1. A vapor deposition method in which a vapor deposition raw material is heated by using a plasma gun capable of forming a plasma flow by generating an electron beam to form a thin film on a substrate opposite to the vapor deposition raw material with respect to the plasma flow. A vapor deposition method comprising: rotating a raw material hearth holding a vapor deposition raw material around a rotation axis substantially vertical to a substrate and guiding a plasma flow to a position deviated from the rotation axis of the raw material hearth of the vapor deposition raw material. 2. The vapor deposition method according to claim 1, wherein a cross section of the raw hearth perpendicular to the rotation axis of the raw hearth has a circular shape. 3. The vapor deposition method according to claim 1, wherein the film forming rate of the thin film is controlled by changing the rotation speed of the raw material hearth. 4. A plasma gun capable of forming a plasma flow by generating an electron beam, and a rotary shaft arranged on the side opposite to the position of the base on which the thin film is formed with respect to the plasma flow by the plasma gun and substantially perpendicular to the base. A vapor deposition apparatus comprising: a raw material hearth that holds a vapor deposition raw material that is rotatable around a substrate; and a magnetic field forming unit that guides a plasma flow at a position deviated from the rotation axis of the raw material hearth. 5. The vapor deposition apparatus according to claim 4, wherein the shape of the cross section of the raw hearth perpendicular to the rotation axis of the raw hearth is circular. 6. The vapor deposition apparatus according to claim 4 or 5, wherein two or more sets of a combination of a plasma gun, a raw material hearth, and a magnetic field forming means are provided in parallel with a substrate.