JP2002030425A - System and method for film deposition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film deposition system and a film deposition method by which electric discharge to a hearth can be stabilized and film deposition can also stabilized over a long period of time. SOLUTION: At film deposition, a gaseous mixture of oxygen and argon is discharged toward a wafer through an annular opening 51c formed in a guide member 251 for guiding a material tablet 53. Owing to the gaseous mixture discharged through the opening 51c, a plasma beam PB can stably be formed, and a homogeneous film can be deposited on the wafer W with superior reproducibility. Moreover, the film stress of the ITO film deposited on the wafer can be reduced, and resistivity can be decreased. Further, formation of a deposit around the guide member 251 by the flow of the gaseous mixture discharged through the opening 51c can be prevented, and stable film deposition can be carried out over a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming apparatus for forming a transparent conductive film on a substrate using a plasma beam.

[0002]

2. Description of the Related Art As an example of a film forming apparatus using a plasma beam, there is an ion plating apparatus disclosed in Japanese Patent Application Laid-Open No. 9-194232. In this ion plating apparatus, a plasma beam from a pressure gradient type plasma gun is guided to a hearth, and the material tablet passed through a hollow cone-shaped guide member provided in the hearth is sublimated at the upper end while sublimating the upper end thereof. The material tablet is made of oxides of indium and tin (ITO), and the evaporating substance emitted from its upper end is ionized in the plasma beam, and the ionized material particles adhere to the surface of the substrate that is conveyed in opposition to the hearth. Then, an ITO film is formed here.

[0003] In film formation of ITO or the like by an ion plating apparatus, high-speed film formation is possible as compared with a sputtering apparatus, and a conductive film having a low specific resistance can be obtained.
Further, there is no problem that nodules are generated in a target which is an evaporation source due to long-time operation unlike a sputtering apparatus.

[0004]

However, in the above-described film forming apparatus, it is desired to stabilize the discharge to the hearth to form a more stable film.

In the above-described film forming apparatus, the same applies to a sputtering apparatus. However, when forming ITO or the like at a high speed, plasma damage occurs to a color filter as a base, or cracks occur in an ITO film or the like due to film stress. May occur.

Further, when a long-time film formation is performed by the above-described film forming apparatus, excess film material generated during the film formation adheres and deposits around the hearth, thereby hindering stable film formation.

Accordingly, an object of the present invention is to provide a film forming apparatus and a film forming method capable of stabilizing discharge to a hearth and hardly causing cracks due to film stress.

The present invention also provides a film forming apparatus capable of preventing deposition of deposits around a hearth even when performing film formation for a long time and stabilizing film formation for a long time. And a film forming method.

[0009]

In order to solve the above-mentioned problems, a film forming apparatus according to the present invention comprises a plasma source for supplying a plasma beam into a film forming chamber, a plasma source arranged in the film forming chamber, and a plasma beam. A hearth for holding the film material, wherein the hearth is around the film material,
It is characterized by having a gas discharge part for discharging a gas to the substrate side arranged opposite to the hearth.

In this case, since the hearth has a gas discharge portion for discharging gas to the substrate side around the film material, a stable plasma beam is formed by being guided by the gas discharged from the gas discharge portion. A uniform film can be formed with good reproducibility. In addition, film stress tends to be reduced in film formation of ITO or the like due to stabilization of the plasma beam. The reason is not clear, but seems to be related to the decrease in Haas potential. Further, since the film material can be prevented from being scattered around the hearth by the flow of the gas, the formation of deposits can be prevented, and stable film formation can be performed for a long time, and the film formation speed may be increased.

The gas discharged around the film material is as follows:
Inert gas such as argon can be used, but film quality can be adjusted as a material gas such as oxygen gas contained in the film material.

In a preferred embodiment of the above apparatus, the hearth includes an annular guide member having a through hole for sending out the tablet-like film material to the substrate side, and a gas discharge portion is formed around the through hole in the guide member. I have. in this case,
In a film forming apparatus of a type in which a film material is continuously supplied in the form of a tablet, a gas flow discharged from the periphery of the film material can be easily formed by using a guide member for feeding out a material tablet.

In a preferred embodiment of the above-mentioned apparatus, the gas discharge portion is an annular gas discharge port formed around the film material. In this case, the gas can be uniformly discharged around the film material.

In a preferred embodiment of the above apparatus, the film material is a material tablet in which oxides of indium and tin are solidified. In this case, it is possible to obtain an ITO film having a small specific resistance and little damage to a base color filter or the like.

In a preferred embodiment of the above apparatus, the apparatus further comprises a magnet disposed annularly around the hearth, or a magnetic field control member comprising a magnet and a coil for controlling a magnetic field above and close to the hearth, wherein the plasma source is an arc source. This is a pressure gradient type plasma gun using discharge. In this case, the magnetic field control member corrects the plasma beam incident on the hearth with a cusp-shaped magnetic field, so that a film having a more uniform thickness can be formed.

Further, according to the film forming method of the present invention, the film material held in the hearth is evaporated by supplying a plasma beam to the hearth disposed in the film forming chamber, and the film material is disposed to face the hearth. A film deposition method for adhering to a surface of a substrate, wherein a gas is discharged to the substrate side around the film material.

In this case, since the hearth has a gas discharge portion for discharging gas toward the substrate around the film material, a uniform film can be formed with a stable plasma beam with good reproducibility. Further, the film stress of the film formed on the substrate is reduced by stabilizing the plasma beam.
Further, the deposition of the film material is prevented from being formed on the hearth, thereby enabling stable film formation for a long time and increasing the film formation rate in some cases.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a view schematically illustrating the entire structure of a film forming apparatus according to a first embodiment. The film forming apparatus includes a vacuum chamber 10 serving as a film forming chamber, a plasma gun 30 serving as a plasma source for supplying a plasma beam PB into the vacuum chamber 10, and a plasma beam PB disposed at the bottom in the vacuum chamber 10. Incident anode member 50
And a transport mechanism 60 that appropriately moves a substrate holding member WH that holds a substrate W such as a liquid crystal glass plate on which a film is to be formed, above the anode member 50.

The plasma gun 30 is disclosed in Japanese Unexamined Patent Publication No. 7-1387.
No. 43, etc.
The main body is provided on the side wall of the vacuum vessel 10.
It is mounted on the tubular part 12. This body part is the cathode 3
1 comprises a glass tube 32 one end of which is closed. Moth
In the lath tube 32, a cylinder 3 made of molybdenum Mo is provided.
3 are fixed to the cathode 31 and are arranged concentrically.
LaB inside the cylinder 33 ₆Disk 34 and tongue formed by
And a pipe 35 formed of a barrel Ta.
End of glass tube 32 opposite to cathode 31
And an end of the cylindrical portion 12 provided in the vacuum container 10.
Means that the first and second intermediate electrodes 41 and 42 are concentrically arranged in series.
Is placed. One of the first intermediate electrodes 41 has a plasma
Built-in annular permanent magnet 44 for converging beam PB
Have been. The plasma beam is also provided in the second intermediate electrode 42.
Electromagnetic coil 45 for converging PB is built in
You. In addition, around the cylindrical portion 12, the gas generated on the cathode 31 side is formed.
From the first and second intermediate electrodes 41 and 42
Steering for guiding plasma beam PB into vacuum vessel 10
A coil 47 is provided.

The operation of the plasma gun 30 is controlled by a gun driving device (not shown). This allows
The power supply to the cathode 31 can be turned on / off, the supply current to the cathode 31 can be adjusted, and the power supply to the first and second intermediate electrodes 41 and 42, the electromagnet coil 45, and the steering coil 47 can be adjusted. be able to. That is, the intensity and distribution of the plasma beam PB supplied into the vacuum chamber 10 can be controlled.

The pipe 35 disposed at the innermost side of the plasma gun 30 is for introducing a carrier gas such as Ar, which is a source of the plasma beam PB, into the plasma gun 30 and eventually into the vacuum vessel 10. It is connected to a carrier gas source 90 via a flow meter 93 and a flow control valve 94.

The anode member 50 disposed in the lower portion of the vacuum vessel 10 comprises a hearth 51 which is a main anode for guiding the plasma beam PB downward, and an annular auxiliary anode 52 disposed around the hearth 51.

The former hearth 51 is formed of a conductive material and is supported by a grounded vacuum vessel 10 via an insulator (not shown). The hearth 51 is controlled to an appropriate positive potential, and sucks the plasma beam PB emitted from the plasma gun 30 downward. The hearth 51 is provided with a plasma beam P from the plasma gun 30.
At the center where B is incident, there is a through hole 51a into which a rod-shaped material tablet 53 as a material evaporation source is loaded.
The material tablet 53 is obtained by sintering and solidifying indium oxide powder and tin oxide powder, which are film materials, and is heated and sublimated by an electric current from the plasma beam PB. A material vapor for forming a film is generated. Material supply device 5 provided below vacuum vessel 10
8, the material tablets 53 are loaded one after another into the through holes 51a of the hearth 51, and the loaded material tablets 5
3 is gradually raised, and even if the upper end of the material tablet 53 evaporates and is consumed, the upper end can always be protruded from the concave portion of the hearth 51 by a fixed amount.

The latter auxiliary anode 52 is constituted by an annular container arranged around the hearth 51 concentrically therewith. The annular container accommodates an annular permanent magnet 55 made of ferrite or the like and a coil 56 concentrically laminated therewith. The permanent magnet 55 and the coil 56 are magnetic field control members, and form a cusp-shaped magnetic field immediately above the hearth 51. Thereby, the direction and the like of the plasma beam PB incident on the hearth 51 can be corrected.

The coil 56 in the auxiliary anode 52 constitutes an electromagnet, and is supplied with power from an anode power supply (not shown) to form an additional magnetic field having the same direction as the central magnetic field generated by the permanent magnet 55. I do. Thereby, the coil 5
6, the current supplied to the hearth 51 can be changed.
Fine adjustment of the direction of the plasma beam PB incident on the substrate becomes possible.

The container of the auxiliary anode 52 is formed of a conductive material similarly to the hearth 51. The auxiliary anode 52 is attached to the hearth 51 via an insulator not shown. By changing the voltage applied to the auxiliary anode 52, the electric field above the hearth 51 can be complementarily controlled. That is, when the potential of the auxiliary anode 52 is made equal to that of the hearth 51, the plasma beam PB is also attracted to this, and the supply of the plasma beam PB to the hearth 51 decreases.
On the other hand, when the potential of the auxiliary anode 52 is reduced to a potential close to the vacuum vessel 10, the plasma beam PB is drawn to the hearth 51 and the material tablet 53 is heated.

The transport mechanism 60 includes a plurality of rollers 62 that are arranged in the transport path 61 at equal intervals in the horizontal direction and support laterally extending edges parallel to the paper surface of the substrate holding member WH from both sides. A driving device (not shown) that rotates the roller 62 at an appropriate speed to move the substrate holding member WH at a constant speed.

The oxygen gas supply device 71 and the carrier gas supply device 72 are placed in the vacuum vessel 10 via the hearth 51.
An appropriate amount of a mixed gas of an oxygen gas and a carrier gas is supplied at an appropriate timing. The supply amount of oxygen gas from the oxygen gas source 71a is adjusted by a flow control valve 71b and a flow meter 71c, and the supply amount of carrier gas from the carrier gas source 90 is adjusted by a flow control valve 72b and a flow meter 72c. . The oxygen gas and the carrier gas whose flow rates have been adjusted through both the supply devices 71 and 72 are mixed, and
The gas is supplied to a gas discharge unit (not shown) provided in the apparatus. In addition, the exhaust device 76 can appropriately exhaust the gas in the vacuum vessel 10 through the vacuum gate 76a by the exhaust pump 76b, and can set the inside of the vacuum vessel 10 to an appropriate degree of vacuum.

FIG. 2 is a side sectional view for explaining a more detailed structure of the hearth 51. As shown in FIG. The hearth 51 includes a base member 151 having a cavity CC for cooling, and a base member 1.
And a cone-shaped guide member 251 fixed on the upper surface 51. The base member 151 and the guide member 251 are fixed so that the centers of the holes 151a and 251a provided respectively are aligned. As a result, a cylindrical through hole 51a for feeding the material tablet 53 upward is formed at the center of the hearth 51.

The base member 151 is made of copper, has high thermal conductivity and conductivity, and is cooled by cooling water supplied to the cavity C. The guide member 251 is also made of copper, is electrically and mechanically connected to the base member 151, and is maintained at an appropriate potential and temperature.

A ring-shaped gas cavity GC is formed inside the guide member 251, and an oxygen gas supply device 71 and a carrier gas supply device 72 are provided through a pipe 59.
Is supplied. The gas cavity GC is
It communicates with the inside of the vacuum vessel 10 via an annular passage RP formed at the top. These gas cavities GC and passages RP
Constitutes a gas discharge unit. The mixed gas supplied to the gas cavity GC is discharged from the opening 51c through the passage RP in a substantially vertical direction. Here, the opening 51c for discharging the mixed gas is formed in an annular shape around the material tablet 53, and the mixed gas discharged from the opening 51c is formed in an annular shape toward the substrate W on which the film is to be formed. Emit.
As a result, a stable plasma beam PB is formed by being guided by the mixed gas discharged from the opening 51c, and a uniform film can be formed on the substrate W with good reproducibility. Further, by stabilizing the plasma beam, the substrate W
The film stress of the ITO film formed thereon is reduced. Furthermore, since the gas flow of the mixed gas serves as a shield to prevent the film material from scattering around, it is possible to prevent the formation of deposits around the guide member 251 and to form a stable film for a long time. become.

The operation of the film forming apparatus shown in FIG. 1 will be described below. During film formation by this film forming apparatus, a discharge is generated between the cathode 31 of the plasma gun 30 and the hearth 51 in the vacuum vessel 10, thereby generating a plasma beam PB. The plasma beam PB reaches the hearth 51 while being guided by a magnetic field determined by the steering coil 47 and the permanent magnet 55 in the auxiliary anode 52. The material tablet 53 supplied to the hearth 51 is heated by the current from the plasma beam PB, and the tip of the material tablet 53 sublimates, from which the vapor of the film material is stably emitted. The vapor is ionized by the plasma beam PB, and adheres to, for example, the surface of the substrate to which a negative voltage is applied to form a coating.

In the film forming apparatus, a mixed gas of oxygen and argon is discharged toward the substrate W from the annular opening 51c formed in the guide member 251 for guiding the material tablet 53 during film formation. The plasma gas PB can be stably formed by the mixed gas discharged from the opening 51c, and a uniform film can be formed on the substrate W with good reproducibility. Further, the film stress of the ITO film formed on the substrate W is reduced. Further, it is possible to prevent a deposit from being formed around the guide member 251 due to the gas flow of the mixed gas discharged from the opening 51c, and it is possible to perform stable film formation for a long time. In addition, since the vaporized particles are guided onto the substrate W by the gas flow discharged from the opening 51c, the film forming speed can be increased.

[Second Embodiment] FIG. 3 is a view for explaining a main part of a film forming apparatus according to a second embodiment. The film forming apparatus according to the second embodiment is a modification of the film forming apparatus according to the first embodiment, and the same portions are denoted by the same reference numerals and the description thereof will not be repeated.

In this case, the hearth 51 is connected to the base member 15.
The mixed gas is discharged from the inner surface of the hole 551a of the guide member 551 fixed on the periphery of the material tablet 53.

A ring-shaped gas port GP constituting a gas discharge portion is formed inside the guide member 551, and mixed gas from the oxygen gas supply device 71 and the carrier gas supply device 72 is supplied through a pipe 59. Supplied. The mixed gas supplied to the gas port GP is discharged from an opening 551c, which is a gas discharge hole formed on the inner surface of the hole 551a, and passes through a gap between the inner surface of the hole 551a and the outer periphery of the material tablet 53 to guide the member 551. Vacuum container 1 from the top of
Discharged within 0. At this time, the mixed gas discharged from the upper end of the guide member 551 is annularly emitted toward the substrate W so as to surround the material tablet 53. As a result, similarly to the first embodiment, a stable plasma beam PB is formed, and a uniform film can be formed on the substrate W with good reproducibility. In addition, the I formed on the substrate W
The film stress of the TO film is reduced. Further, the guide member 55
1 can be prevented from forming a deposit, and stable film formation can be performed for a long time.

As described above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to the above embodiments.
For example, when a film is formed using an oxide such as SiO ₂ or MgO as another film material, a gas is discharged from the opening 51 c provided in the guide member 251 or the opening 551 c provided in the guide member 551. By discharging a gas from the substrate, a high-quality film can be stably formed.

The gas discharged from the hearth 51 is not limited to argon or oxygen. For example, another inert gas such as Ne can be used, and another gas such as nitrogen can be mixed.

[0039]

As is clear from the above description, according to the film forming apparatus of the present invention, since the hearth has the gas discharge portion for discharging the gas to the substrate side around the film material, the gas is discharged from the gas discharge portion. A stable plasma beam is formed by the guided gas, and a uniform film can be formed with good reproducibility. Further, the film stress of the film formed on the substrate is reduced by stabilizing the plasma beam. Further, since the film material can be prevented from being scattered around the hearth by the flow of the gas, the formation of deposits can be prevented, and stable film formation can be performed for a long time, and the film formation speed may be increased.

Further, according to the film forming method of the present invention, since the hearth has the gas discharge portion for discharging the gas to the substrate side around the film material, a uniform film is formed with a stable plasma beam with good reproducibility. be able to. Further, by stabilizing the plasma beam, the film stress of the film formed on the substrate is reduced, and the specific resistance of the conductive film is reduced. Further, it is possible to prevent a deposit of a film material from being formed on the hearth, thereby enabling stable film formation for a long time.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall structure of a film forming apparatus according to a first embodiment.

FIG. 2 is a side sectional view illustrating a structure of a hearth incorporated in the film forming apparatus of FIG.

FIG. 3 is a side sectional view illustrating a structure of a hearth incorporated in a film forming apparatus according to a second embodiment.

[Explanation of symbols]

 Reference Signs List 10 vacuum container 30 plasma gun 47 steering coil 50 anode member 51 hearth 51a through hole 51c opening 52 auxiliary anode 53 material tablet 58 material supply device 60 transport mechanism 71 oxygen gas supply device 71a oxygen gas source 72 carrier gas supply device 76 exhaust device 90 Carrier gas source 151 Base member 251 551 Guide member PB Plasma beam W Substrate WH Substrate holding member

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yukio Kobuya 5-2 Sokai-cho, Niihama-shi, Ehime Prefecture Sumitomo Heavy Industries, Ltd. Niihama Works F-term (reference) 4K029 BA50 BC09 CA03 DA05 DA06 DB05 DB12 DB15 DD06

Claims (6)

[Claims] 1. A film forming apparatus comprising: a plasma source that supplies a plasma beam into a film forming chamber; and a hearth that is disposed in the film forming chamber and guides the plasma beam and holds a film material. A film forming apparatus, wherein the hearth has a gas discharge part for discharging a gas to a substrate side arranged opposite to the hearth around the film material. 2. The hearth includes an annular guide member having a through hole for sending out the tablet-like film material to the substrate side, and the gas discharge unit is provided around the through hole in the guide member. The film forming apparatus according to claim 1, wherein the film forming apparatus is formed. 3. The film forming apparatus according to claim 1, wherein the gas discharge unit is an annular gas discharge port formed around the film material. 4. The film forming apparatus according to claim 1, wherein the film material is a material tablet obtained by solidifying an oxide of indium and tin. 5. A magnetic field control member, comprising a magnet or a magnet and a coil arranged in an annular shape around the hearth, for controlling a magnetic field above and close to the hearth, wherein the plasma source uses an arc discharge. 5. The film forming apparatus according to claim 1, wherein the film forming apparatus is a pressure gradient type plasma gun. 6. A plasma beam is supplied to a hearth disposed in a film forming chamber, thereby evaporating the film material held on the hearth and forming a film on a surface of a substrate disposed opposite to the hearth. A film forming method for attaching, wherein a gas is discharged to the substrate side around the film material.