JP2002294436A - Method for forming film of silicon oxide nitride - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a film of silicon oxide nitride, which can form the film at low temperature and a high film forming rate. SOLUTION: This method comprises ionizing evaporated particles from a material rod 53 into a highly activated state by a plasma beam PB, launching it into a substrate W, and making silicon oxide and silicon deposited on the substrate W react with nitrogen gas and oxygen gas in atmospheric gas, to form a SiOx Ny film on the substrate W. The method further comprises regulating a content ratio of the nitrogen gas or the oxygen gas in the atmospheric gas in the above process, to regulate the content ratio of SiOx Ny in a wide range. Then, the SiOx Ny film formed on the substrate W can be dense and uniform without keeping the substrate W at high temperature, because the silicon oxide or the like evaporated from a hearth 51 launches into the substrate W at a sufficiently activated state by the plasma beam PB.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Since a silicon oxynitride film has high transparency while preventing permeation of water vapor and oxygen, it is expected to be widely used as a barrier film of a plastic display in the future. As a method for forming such a silicon oxynitride film, for example, there is a method using a reactive sputtering method. In this reactive sputtering method,
Under an atmosphere of argon and oxygen, argon for sputtering is incident on a target made of silicon nitride, and sputtered particles such as silicon nitride emitted from the target are turned into plasma at a high frequency. By causing an oxidation reaction while depositing the activated sputter particles on the substrate, a silicon oxynitride film can be formed on the substrate.

[0003]

However, in the above-mentioned reactive sputtering method, when an insulator such as silicon nitride is used as a target, there is a certain limit to the amount of energy input to the target. For this reason, in the formation of silicon oxynitride using a reactive sputtering method, the film formation rate has a certain upper limit, and it is difficult to improve the throughput.

[0004] In addition, the reactive sputtering method cannot increase the efficiency of forming sputter particles into plasma, and the sputter particles have low reactivity. For this reason, the reactive sputtering method cannot form a high-quality silicon oxynitride film on a low-temperature substrate, and is not suitable for forming a silicon oxynitride film on a relatively heat-resistant material such as an organic material. Not suitable.

Accordingly, an object of the present invention is to provide a method for forming a silicon oxynitride film which can form a film at a high film forming rate at a low temperature.

[0006]

In order to solve the above problems, a method for forming a silicon oxynitride film according to the present invention comprises a film material containing silicon oxide as a main component in a material evaporation source disposed in a film forming chamber. And evaporating the film material from the material evaporation source while supplying a plasma beam toward the material evaporation source, and disposed in the film forming chamber so as to face the material evaporation source. Attaching a vaporized particle of the film material to the surface of the substrate, and introducing an atmosphere gas containing nitrogen gas into the film forming chamber when the vaporized particle is adhered to the substrate. Here, the film material is silicon oxide such as SiO or SiO ₂ ,
N may be included.

In the above-described film forming method, when vaporized particles of a film material containing silicon oxide as a main component are adhered to a substrate,
Since an atmosphere gas including a nitrogen gas is introduced into the film formation chamber, a silicon oxynitride film obtained by nitriding silicon oxide can be formed over a substrate. At this time, since the plasma beam is supplied toward the material evaporation source, the material evaporation source can be efficiently heated, and the film material can be efficiently evaporated. Also,
Since the film material evaporated from the material evaporation source enters the substrate in a sufficiently activated state via the plasma beam,
A dense and uniform silicon oxynitride film can be formed over a substrate.

[0008] In a specific embodiment of the above method, the atmospheric gas includes oxygen gas. In this case, a silicon oxynitride film having a high oxygen composition ratio can be formed.

In a specific embodiment of the above method, the component ratio of nitrogen gas in the atmospheric gas is adjusted. In this case, the composition ratio of oxygen and nitrogen in the obtained silicon oxynitride film can be adjusted to a desired value.

In a specific embodiment of the above method, at least before the film material starts to evaporate, a predetermined inert gas is supplied around the material evaporation source. In this case, since the plasma can be effectively guided around the material evaporation source, the material evaporation source can be quickly and reliably heated to achieve rapid film formation.

In a specific embodiment of the above method, the material evaporation source is formed in a columnar tablet, and when the film material is evaporated, the tablet is fed out toward the substrate. In this case, since film formation can be performed while keeping the amount of protrusion of the tablet as the material evaporation source constant, continuous film formation can be performed in a stable state for a long time.

In film formation, a material evaporation source is held on a hearth serving as an anode in order to guide a plasma beam.
Around the hearth, a magnetic field control member composed of a magnet or a magnet and a coil and configured to control a magnetic field above and close to the hearth can be annularly arranged. Further, the plasma source can be a pressure gradient type plasma gun utilizing arc discharge. In this case, the magnetic field control member corrects the plasma beam incident on the hearth with a cusp-shaped magnetic field, thereby forming a film having a more uniform thickness.

[0013]

FIG. 1 is a diagram schematically illustrating the overall structure of a film forming apparatus for performing a film forming method according to an embodiment of the present invention.

This film forming apparatus includes a vacuum chamber 1 serving as a film forming chamber.
0, a plasma gun 30 serving as a plasma source for supplying the plasma beam PB into the vacuum vessel 10, an anode member 50 disposed at the bottom of the vacuum vessel 10 and receiving the plasma beam PB, and a film formation target. A transport mechanism 60 that appropriately moves the substrate holding member WH that holds the substrate W above the anode member 50;

The plasma gun 30 is disclosed in Japanese Patent Application Laid-Open No. 9-1942.
No. 32, 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 coaxially 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 voltage 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 vessel 10 can be controlled.

A pipe 35 disposed at the innermost side of the plasma gun 30 introduces a carrier gas composed of an inert gas such as Ar, which is a source of the plasma beam PB, into the plasma gun 30 and the vacuum vessel 10. It is connected to an inert 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 includes a hearth 51 as 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 by the anode power supply 80, and the plasma beam PB emitted from the plasma gun 30 is
Is sucked down. The hearth 51 has a through hole TH in which a columnar or rod-shaped material rod 53 as a material evaporation source is loaded at a central portion where the plasma beam PB from the plasma gun 30 is incident. This material rod 53
Is a tablet formed by forming SiO or SiO ₂ into a predetermined shape as a film material. The tablet is heated by an electric current from the plasma beam PB and sublimates to generate material particles for forming a silicon oxynitride film on a substrate. I do. The material supply device 58 provided at the lower portion of the vacuum vessel 10 has a structure in which the material rods 53 are sequentially loaded into the through holes TH of the hearth 51 and the loaded material rods 53 are gradually raised. Even if the upper end of the heat sink evaporates and is consumed, the upper end can always be projected from the recess of the hearth 51 by a fixed amount.

The latter auxiliary anode 52 is constituted by an annular container arranged concentrically around the hearth 51. 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.
An additional magnetic field is formed so as to be in the same direction as the magnetic field on the center side generated by. That is, by changing the current supplied to the coil 56, the direction of the plasma beam PB incident on the hearth 51 can be finely adjusted.

The container of the auxiliary anode 52 is also made of a conductive material similarly to the hearth 51. The auxiliary anode 52 is attached to the hearth 51 via an insulator not shown. The electric field above the hearth 51 can be complementarily controlled by changing the voltage applied from the anode power supply 80 to the auxiliary anode 52. That is, when the potential of the auxiliary anode 52 is made the same as that of the hearth 51, the plasma beam PB is also attracted to the plasma beam PB and the plasma beam PB
Supply is reduced. On the other hand, when the potential of the auxiliary anode 52 is reduced to the same degree as that of the vacuum vessel 10, the plasma beam PB is drawn to the hearth 51, and the material rod 53 is heated.

The transfer mechanism 60 functions as a substrate holding means, and includes a number of rollers 62 arranged at equal intervals in the horizontal direction in the transfer path 61 to stably support the edge of the substrate holding member WH at a plurality of positions. A driving device (not shown) for rotating these rollers 62 at an appropriate speed and moving the substrate holding member WH in the horizontal direction at a constant speed is provided.

The oxygen gas supply device 71 is a gas supply means for supplying an appropriate amount of oxygen gas to the vacuum vessel 10 at an appropriate timing as an atmospheric gas. A supply line from an oxygen gas source 71a that contains oxygen gas is connected to the vacuum vessel 10 via a flow control valve 71b and a flow meter 71c.

The nitrogen gas supply device 72 is a gas supply means for supplying an appropriate amount of nitrogen gas to the vacuum vessel 10 at an appropriate timing as an atmospheric gas. A supply line from a nitrogen gas source 72a containing nitrogen gas is connected to the vacuum vessel 10 via a flow control valve 72b and a flow meter 72c.

The hearth gas supply device 73 supplies an inert gas such as Ar to the hearth 51 at an appropriate timing and at an appropriate amount. The inert gas branched from the inert gas source 90 is guided to a gas introduction port (not shown) provided in the hearth 51 via the flow rate control valve 73b and the flow meter 73c of the hearth gas supply device 73, and Rod 5
3 is discharged around.

The evacuation device 76 evacuates the gas in the vacuum vessel 10 through an evacuation pump 76b through a vacuum gate 76a.

The vacuum pressure measuring device 77 can measure the partial pressure of oxygen gas, nitrogen gas and the like in the vacuum vessel 10, and the measurement result is monitored by the atmosphere control device 78.

The atmosphere control device 78 supplies oxygen gas, nitrogen gas, and Ar gas into the vacuum vessel 10 via an oxygen gas supply device 71, a nitrogen gas supply device 72, a hearth gas supply device 73, and the like. The amount can be adjusted individually. Further, the atmosphere control device 78 includes the vacuum pressure measuring device 7.
7, the operations of the oxygen gas supply device 71, the nitrogen gas supply device 72, the hearth gas supply device 73, the exhaust device 76, and the like are controlled, and the oxygen gas, the nitrogen gas, It is also possible to control the partial pressure of Ar gas to a target value.

FIG. 2 is a side sectional view for explaining a more detailed structure of the hearth 51 and the like constituting the device shown in FIG.
The hearth 51 includes a first base member 51a having a cooling cavity CA, a cylindrical second base member 51b fixed on the first base member 51a, and a cone fixed on the second base member 51b. Guide member 51c. The first base member 51a, the second base member 51b, and the guide member 51c are fixed so that the centers of the openings THa, THb, and THc provided in the first base member 51a, the second base member 51b, and the THc are aligned. As a result, a cylindrical through hole TH is formed at the center of the hearth 51 for feeding out the material rod 53 made of SiO ₂ or SiO upward.

The two base members 51a and 51b are made of copper,
It has high thermal conductivity and conductivity, and is appropriately cooled by cooling water supplied to the cavity CA provided in the first base member 51a.

The guide member 51c is made of carbon, has high conductivity and heat resistance, and draws the plasma beam PB (see FIG. 1). The guide member 51c can be formed of a refractory metal as another suitable material.

The first and second base members 51a, 51a,
In 1b, a gas introduction pipe 51f to which a pipe extending from the hearth gas supply device 73 is connected is formed. The distal end of the gas introduction pipe 51f communicates with the inner surface of the through hole TH. That is, the Ar gas supplied from the inert gas source 90 is discharged to the side surface of the material rod 53 via the gas introduction pipe 51f. Thereby, the density of Ar gas above the guide member 51c increases, and the plasma beam is drawn to the guide member 51c. That is, the material rod 5
3 can be efficiently supplied with plasma, and the efficiency of film formation can be increased.

Hereinafter, the operation of the film forming apparatus shown in FIG. 1 will be described.
explain. When forming a film, a nitrogen gas is previously stored in the vacuum container 10.
Atmosphere gas such as heat is introduced. Next, the plasma gun 30
Between the cathode 31 and the hearth 51 in the vacuum vessel 10
To generate a plasma beam PB.
You. This plasma beam PB is applied to the steering coil 4
7 and the permanent magnet 55 in the auxiliary anode 52, etc.
And reaches the hearth 51. At this time,
Ar gas is placed around the material rod 53 housed in the source 51.
Is supplied, it is made of silicon oxide and has low conductivity
Even if the material rod 53 is used, the plasma beam PB
Is attracted. Exposed to plasma in this way
The material rod 53 is gradually but surely heated.
The material rod 53 is sufficiently added by the plasma beam PB.
When heated, the material rod 53 sublimates, from which the oxide silicon
Evaporated particles such as silicon and silicon are emitted. This evaporating grain
The ions are ionized by the plasma beam PB,
And enters the substrate W. Deposited on substrate W
Silicon oxide and silicon
Reacts with oxygen and oxygen gas to form SiO_xN_yThe membrane is shaped
Is done. At this time, nitrogen gas or oxygen gas in the atmosphere gas
By adjusting the component ratio of_xN _yComposition of
The ratio can be adjusted over a wide range. Here, Haas 5
Silicon oxide and the like evaporated from 1 are converted into a plasma beam PB
Incident on the substrate W in a fully activated state
Therefore, the substrate W can be formed on the substrate W without holding the substrate at a high temperature.
SiO formed_xN_yMaking the membrane dense and uniform
Can be.

Note that once the material rod 53 is heated and silicon oxide or the like starts to evaporate, the material rod 53 has conductivity and the plasma beam PB starts to directly enter the material rod 53. The supply of Ar gas to the fuel cell can be stopped or reduced.

In a specific operation example, a vacuum during film formation is used.
Atmospheric pressure in the container 10 is 10^-2About Pa ~ 1Pa
Was. At this time, the ratio of nitrogen gas is set in the range of 20% to 80%.
SiO 2 on the substrate W while changing_xN_yA film was formed. Ma
And changing the ratio of oxygen gas in the range of 0% to 50%.
On the substrate W_xN_yA film was formed. More specific
In the operation example, the discharge current from the plasma gun 30 is:
It changed within the range of 50A to 500A. Obtained SiO
_xN_yThe film has a high transmittance to visible light and a film formation rate
Was 50 to 150 nm · m / min. In addition, conventional
Film formation rate of the reactive sputtering of 5 to 10 nm · m /
min, the film forming method of
It can be seen that the size increases by one digit or more. Also, the substrate W
Even if the temperature of the SiO.sub.2 is as low as 100.degree.
_xN_yA film was formed. That is, on a plastic substrate
Also, good SiO_xN_yA film could be formed.
As is clear from the above description, the film forming method of the embodiment
The resulting SiO_xN _yThe film is made of plastic liquid crystal or
The plastic substrate of the organic EL
It can be used as a rear membrane. Also, of the embodiment
SiO_xN_yThe membrane is used for packaging medical or beverage packaging.
It can be used as a rear membrane. Also, of the embodiment
SiO_xN_yThe film is made of liquid crystal display or organic EL display.
Use as an alkali barrier film for glass substrates
Can be used. In addition, the SiO of the embodiment_xN_yfilm
Is used as a protective film for color filters of liquid crystal displays
Can be used. The following are specific examples.
This will be partially described.

Example 1 In this case, the conditions for film formation were as follows. As the material rod 53, SiO 2
_Two round bars (φ30 mm × 80 mm) were used. As the guide member 51c for guiding the material rod 53, the inner diameter is 31m.
m of carbon was used. At the time of film formation, the material rod 5
The material rod 53 was gradually raised so that the upper end position was not changed by the sublimation of No. 3. Also, when forming a film,
Ar gas of 60 sccm was introduced into the vacuum vessel 10. Among them, Ar gas of 20 sccm was introduced from the hearth 51 side, that is, from the gas introduction pipe 51f. In parallel with this, 100 sccm of nitrogen gas was introduced into the vacuum vessel 10. Then, the atmospheric pressure in the vacuum vessel 10 during the film formation is set to 0.
33 Pa (2.5 mtorr). The discharge current from the plasma gun 30 during the film formation was 150 A. On the other hand, the thickness of the substrate W to be formed is 0.7 m
The temperature of the substrate W was kept at 50 ° C. by using a glass plate of m. During the film formation, the substrate W is transferred to the hearth 51 by the transfer mechanism 60.
It was moved upward at a speed of 15 mm / sec.

The plasma beam PB is incident on the hearth 51 from the plasma gun 30 immediately before the start of film formation. However, after the hearth 51 is heated, until the material rod 53 of SiO ₂ starts to evaporate stably. 100sccm
Is supplied to the gas introduction pipe 51f of the hearth 51,
After the start of stable evaporation, as described above, 20 sccm Ar
The gas was supplied to the hearth 51.

The SiO _x N _y film obtained as described above has a thickness of 70 nm and a visible light transmittance of 90% (wavelength: 5 nm).
50 nm). XPS (X-ray photoelectron sp
According to ectroscopy), the composition ratio of the obtained SiO _x N _y film was Si: O: N = 36: 59: 5.

Example 2 In this case, the conditions for film formation were as follows. As the material rod 53, SiO 2
(Φ30 mm × 10 mm) was used. As a guide member 51c for guiding the material rod 53, an inner diameter of 31 mm
Was used. At the time of film formation, the material rod 53
The material rod 53 was gradually raised so that the upper end position was not changed by the sublimation. During film formation, Ar gas of 60 sccm was introduced into the vacuum vessel 10. Among them, Ar gas of 20 sccm was introduced from the hearth 51 side, that is, from the gas introduction pipe 51f. In parallel with this, 100 sccm of nitrogen gas was introduced into the vacuum vessel 10. Then, the atmospheric pressure in the vacuum chamber 10 during the film formation is set to 0.2.
Pa (1.5 mtorr). The discharge current from the plasma gun 30 during the film formation was 70 A. On the other hand, a glass plate having a thickness of 0.7 mm was used as a substrate W on which a film was to be formed, and the temperature of the substrate W was kept at 50 ° C. During film formation, the substrate W was moved above the hearth 51 at a speed of 9 mm / sec.

A plasma beam PB is incident on the hearth 51 from the plasma gun 30 immediately before the start of the film formation. Is supplied to the hearth 51, and after the stable evaporation starts,
As described above, Ar gas of 20 sccm was supplied to the hearth 51.

The SiO obtained as described above_xN_yfilm
Has a thickness of 90 nm and a visible light transmittance of 80% (wavelength 5
50 nm). According to XPS, the obtained SiO
_xN _yThe composition ratio of the film is as follows: Si: O: N = 43: 43: 14
Met.

Although the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment.
For example, the material rod 53 is not limited to SiO ₂ or SiO,
It is possible to include those having an intermediate composition of these,
N can be contained, and a trace element can be contained within a range that does not affect the characteristics.

[0044]

As is apparent from the above description, according to the method for forming a silicon oxynitride film of the present invention, when vaporized particles of a film material containing silicon oxide as a main component are adhered to a substrate, the formation of the silicon oxynitride film is prevented. Since an atmospheric gas including a nitrogen gas is introduced into the film chamber, a silicon oxynitride film obtained by nitriding silicon oxide can be formed over a substrate. At this time, since the plasma beam is supplied toward the material evaporation source, the material evaporation source can be efficiently heated, and the film material can be efficiently evaporated. Further, since the film material evaporated from the material evaporation source enters the substrate in a state of being sufficiently activated via the plasma beam, even if the substrate is at a relatively low temperature, a dense and uniform oxidation is performed on the substrate. A silicon nitride film can be formed.

[Brief description of the drawings]

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

FIG. 2 is a side sectional view illustrating the structure of a hearth.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vacuum container 30 Plasma gun 50 Anode member 51 Hearth 51c Guide member 51f Gas introduction pipe 52 Auxiliary anode 53 Material rod 55 Permanent magnet 56 Coil 58 Material supply device 60 Transport mechanism 71 Oxygen gas supply device 72 Nitrogen gas supply device 73 Heart gas Supply device 76 Exhaust device 78 Atmosphere control device 90 Inert gas source PB Plasma beam TH Through hole W Substrate

Claims (5)

[Claims] 1. A step of housing a film material containing silicon oxide as a main component in a material evaporation source disposed in a film formation chamber, and supplying a plasma beam toward the material evaporation source while supplying a plasma beam to the material evaporation source. A step of evaporating the film material; a step of attaching vaporized particles of the film material to a surface of a substrate arranged in the film forming chamber so as to face the material evaporation source; and Introducing an atmospheric gas containing a nitrogen gas into the film forming chamber when attaching the film. 2. The method according to claim 1, wherein the atmosphere gas includes an oxygen gas. 3. The method for forming a silicon oxynitride film according to claim 1, wherein a component ratio of a nitrogen gas in the atmosphere gas is adjusted. 4. The method according to claim 1, wherein a predetermined inert gas is supplied around the material evaporation source at least at a stage before the film material starts to evaporate. Of silicon oxynitride. 5. The material evaporation source according to claim 1, wherein the material evaporation source is formed in a columnar tablet, and when the film material is evaporated, the tablet is fed out toward the substrate. The method for forming a silicon oxynitride film according to any one of the above.