JP3122600B2 - High frequency plasma film forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency plasma film forming apparatus. More specifically, the present invention relates to a new high-frequency plasma film forming apparatus capable of forming a large area of various functional films with high uniformity, high quality, and high productivity.

[0002]

2. Description of the Related Art Conventionally, as a method for forming thin films for various compositions and various purposes, vaporized substances are deposited on a solid substrate in a gas phase or reacted with the surface of the solid substrate. For example, a PVD method such as a CVD method, a sputtering method, a vapor deposition method, and an ion plating method is well known. However, in reality, these various methods still have problems to be solved.

For example, in the case of forming a transparent conductive film of ITO (indium tin oxide), which has recently been attracting attention as an application to a liquid crystal substrate, for example, in the case of the CVD method, hydrolysis of chloride is performed. Reaction or thermal decomposition of organic compounds
Although a TO film is formed, the film formation by the CVD method has an advantage that the film forming process is simple and the film forming apparatus is inexpensive, but the reaction temperature in the film forming process is high and 400 ° C. Therefore, it is difficult to form an ITO film on a substrate material having a low heat-resistant temperature such as a TFT element or a color filter film. Further, it is difficult to obtain an ITO film having a low resistance because optimization cannot be performed by controlling a donor that creates an oxygen deficiency state by fine control of the composition. Further, there is another problem that a harmful gas is generated in the film forming process.

[0004] In a vapor deposition method which is a PVD method, 5 w
t. % Of an ITO sintered body pellet containing Sn of about% by evaporation in a vacuum by resistance heating or electron beam to control an oxygen deficient donor while introducing an appropriate amount of oxygen gas. Is formed. In the sputtering method, an ITO film is formed while introducing an oxygen gas by ionizing an Ar gas by direct current or high frequency discharge and colliding the Ar ion gas with a metal or oxide target. Further, in the high frequency ion plating method, a DC glow discharge is combined with a vacuum deposition. This high-frequency ion plating method has a feature that the combination of the adhered substance and the substrate substance is wider than vacuum deposition, and that the film wraps around well and the adhesion strength is increased. Since a film can be formed even at a film forming pressure of 10 ⁴ to 10 ⁵ Torr, a film having excellent smoothness and reactivity and having a high particle density can be obtained at a low temperature.

[0005] In such a PVD method, an oxygen-deficient donor can be controlled by introducing oxygen in a vacuum.
It is easy to obtain a low-resistance ITO film. Also, PV
In the method D, since an ITO film can be formed at a low temperature, the ITO film can be formed on a substrate material having a low heat-resistant temperature such as a TFT element or a color filter film.

However, none of these conventional methods can be said to be sufficient for responding to the necessity of a higher-performance transparent conductive film and ITO film as the display becomes larger and higher definition. That is the fact. However,
Among the conventional methods, in various film formations including the above-mentioned ITO film, the film adhesion density, the surface smoothness, the composition uniformity, and the film formation at a lower temperature are possible. The high-frequency excitation ion plating method has great potential for the future.

Therefore, taking advantage of the advantage of the high-frequency excitation ion plating method, a new improvement is realized which enables a high-precision and high-quality uniform thin film to be formed even on a substrate having a larger area than ever before. It was desired.

[0008]

According to the present invention, there is provided a high-frequency plasma film forming apparatus for forming a film by using high-frequency discharge plasma, wherein an evaporation source is provided and a substrate surface is provided. is disposed have at least one or more of the grid electrode in the vicinity, and the grid electrode and the evaporation source
A high-frequency power supply is connected to the grid electrode and the coiled high -frequency antenna, and a high-frequency power supply is connected to the grid electrode and the coiled high -frequency antenna.
Provided is a high-frequency plasma film forming apparatus characterized in that a plasma generated by application of a high-frequency voltage to a tenner excites an evaporating substance evaporated from an evaporation source and forms a film on a substrate surface.

[0009] Then, the present invention is the film forming apparatus, the substrate and the DC bias power supply is connected, that the substrate is connected to a high frequency power source, grayed ripple <br/> de electrodes And that a shield that covers the entire surface or a part of the substrate is provided so as to be detachable and attachable to the entire surface or a part of the substrate surface. Provide as one of.

The present invention also relates to a high-frequency plasma film-forming method for forming a film using high-frequency discharge plasma, wherein a film-forming evaporating substance evaporated from an evaporation source is disposed in opposition near a substrate surface and is connected to a high-frequency power supply. Connected grid electrodes,
And between the grid electrode and the evaporation source
There is also provided a high-frequency plasma film forming method characterized in that a film is formed on a substrate surface by being excited by discharge plasma generated by a coiled high-frequency antenna connected to a high-frequency power supply .

[0011] This method is also characterized in that the film-forming evaporating substance comprises one or more of metals, inorganic substances and organic substances, and that a conductive thin film such as an ITO film is formed. .

[0012]

According to the present invention, as described above, by providing a grid electrode connected to a high-frequency power source near a substrate, a large-area high-frequency antenna can be realized to improve the overall plasma density in a film forming apparatus, and to improve the plasma density near the substrate. With a large adhesion strength due to an increase in the number of excited particles incident on the substrate due to an increase in the number of excited particles therein, it is possible to form a film with a larger area having excellent crystallinity and composition uniformity.

Hereinafter, the present invention will be described in more detail with reference to examples. Of course, the present invention is not limited by the following examples.

[0014]

Embodiment 1 FIG. 1 is a structural view showing an ion plating apparatus as a high-frequency plasma film forming apparatus according to a conventional method. In this conventional apparatus, a substrate (2) is installed on a substrate holder (3) in an upper portion of a chamber (1), and an evaporation source (9) and an electron gun are installed below the substrate (2). (9)
A coiled high-frequency antenna (6) to which a high-frequency power supply (8) is connected via a matching box (7) is provided above. For example, an inert gas such as Ar (argon) or a reaction gas is introduced into the chamber (1) via the mass flow controller (10). Then, plasma is generated by applying a high-frequency electric field to the coiled high-frequency antenna (6), and excited particles are generated by the plasma, and the excited particles are deposited on the substrate (2). At this time, the film forming speed and the film thickness are controlled by interlocking the electron gun and the crystal oscillation type film thickness monitor (5). Further, the substrate holder (3) is rotated to make the film thickness distribution uniform. A micro heater for heating the substrate is also provided on the substrate. As described above, in the conventional film forming apparatus, a thin film such as an ITO film is formed by generating plasma by the coiled high-frequency antenna (6).

On the other hand, FIG. 2 is a structural view illustrating a high-frequency plasma film forming apparatus having a grid electrode according to an embodiment of the present invention. In this apparatus, a grid electrode (11) having an appropriate mesh size is installed at a position directly below the vicinity of the substrate (2), and a grid box (7) for adjusting impedance matching to the grid electrode (11). And a high frequency power supply (8). The chamber (1) is formed by the grid electrode (11).
A high-frequency plasma is generated on the whole to form a film.

In this case, the arrangement position of the grid electrode (11) is appropriately determined along with the input power, its mesh size, the overall size, and the like according to the object and purpose of film formation. In the case of the conventional device, the distance between the upper end of the coiled high-frequency antenna (6) and the surface of the substrate (2) is about 1/20 to 1/5, which is closer to the surface of the substrate (2). It is arranged almost immediately below (2).
As a general rule of thumb, the mesh size is 1/500 to 1/5 of the entire size of the grid electrode (11), for example, its diameter for a circular electrode and its diagonal length for a square electrode. square Messi Interview with 0 of one side
It is possible to size. Of course, these numbers
, The entire or size of the film forming apparatus, various conditions, for example the deposition area, deposition rate, film thickness, degree of vacuum, gas pressure, the distance of the high-frequency power, and the grid electrode (11) and the substrate (2) or the like Is changed as appropriate.

With respect to the mesh size of the grid electrode (11), the amount of ions incident on the surface of the substrate (2) and participating in film formation changes depending on the size, and accordingly, the film formation rate and film quality also change. Will change. For example, there is an optimum mesh size for the plasma density near the substrate (2), and an optimum size for the smoothness of the film formation surface. The mesh size may be determined in consideration of these viewpoints. Embodiment 2 FIGS. 3 and 4 show another example of the film forming apparatus of the present invention. In the example of FIG. C.
Bias has a structure that can be arbitrarily connected, and in the example of FIG. 4, a high frequency power supply is also connected to the substrate (2). Thus, D.E. C. Application of a high-frequency electric field to Bias or the substrate (2) is also possible in the present invention.

Further, the grid electrode (11) also has a ground potential, and a plurality of grid electrodes (11) may be disposed facing the substrate (2) via an appropriate space. Then, a conventional coiled high-frequency antenna may be provided together with the grid electrode (11). This measure is also effective from the viewpoint of increasing the degree of ionization of the particles. Example 3 Using the apparatus according to the conventional method shown in FIG. 1 and the apparatus according to the present invention shown in FIG.
/ Sec, an ITO film having a thickness of 1500 ° was formed.

In each of the cases of FIGS. 1 and 2,
The height of the chamber (1) is 150 cm and its inner diameter is 10
5 cm, and the substrate (2) is 300 mm × 400 mm
, And four glass plates were held in a chamber (1) by a substrate holder (3) and rotated. Coiled high-frequency antenna (6) of the device of FIG.
Is a position having a diameter of 40 cm and a distance between the upper end thereof and the substrate (2) being 90 cm, and a grid electrode (11) of the apparatus in FIG. 2 is located at a position where the distance from the substrate (7) is 10 cm. It was arranged. The grid electrode (11) has a diameter of 80c.
m and a mesh size of 5 mm × 5 mm was used.

In forming an ITO film, I was used as an evaporation source material.
Using a TO film, the film was evaporated by an electron gun, and an oxygen gas was introduced together with an argon gas to form a film. At this time, the ITO film was formed by changing the introduced oxygen flow rate and the high-frequency power value. A film formation temperature of 300 in both devices
The lowest resistivity is obtained at the time of film formation at 500 ° C. and high-frequency power of 500 W. In the conventional method of FIG. 1, the oxygen flow rate at that time was about 50 SCCM, and in the method using the apparatus of the present invention in FIG. 2, it was about 30 SCCM. Table 1 shows IT by conventional methods (sputtering and ion plating).
It shows respective electrical characteristic values of the O film and the ITO film according to the present invention, and general values of the electrical characteristics of the ITO film. As is clear from Table 1, it is understood that better characteristics are obtained than the ITO film obtained by the conventional high-frequency ion plating apparatus. In addition, the transmittance of the ITO film in the visible region was similar to that of the conventional method.

[0021]

[Table 1]

A scanning electron microscope (SEM) image of the obtained ITO film was observed. FIG. 5 is a diagram showing an IT device using a conventional device.
3 shows an SEM image of an O film. FIG. 6 shows an SEM image of the ITO film obtained by the apparatus of the present invention. Each of them was formed under the following conditions. High-frequency power: 500 W Oxygen flow rate: 50 SCCM Film forming temperature: 300 ° C. Film forming rate: 3 ° / sec Film thickness: 1500 ° As is clear from FIGS.
Although the film particles of the TO film grow in a columnar shape, it can be seen that the ITO film obtained by the grid method of the present invention has extremely excellent smoothness.

The same is true for AFM (200 μm × 20
7 and FIG. 8 showing 0 .mu.m) and the difference between FIGS. 9 and 10 according to the present invention. Further, a transmission electron microscope (TEM) image and an electron diffraction image of the ITO film were observed. FIG. 11 shows a TEM image and an electron diffraction image of the ITO film according to the conventional method, and FIG. 12 shows an ITO film according to the grid method of the present invention.
2 shows a TEM image and an electron diffraction image of the film. As is clear from these, the ITO film according to the present invention has a sharper Debye-Scherrer ring than the ITO film according to the conventional method, and has excellent crystallinity despite being polycrystalline.

[0024]

Since the present invention is configured as described above in detail, it is possible to uniformly form a film with good crystallinity and excellent smoothness even on a large-area substrate.

[Brief description of the drawings]

FIG. 1 is a structural view of a conventional film forming apparatus.

FIG. 2 is a structural diagram of a high-frequency plasma film forming apparatus provided with a grid electrode as one embodiment of the present invention.

FIG. 3 is a structural view of an apparatus according to another embodiment of the present invention.

FIG. 4 is a structural view of a device according to still another embodiment of the present invention.

FIG. 5 is an SEM image photograph replacing a drawing of an ITO film according to a conventional method.

FIG. 6 is a SEM image photograph replacing a drawing of an ITO film formed by the grid method of the present invention.

FIG. 7 is an AFM image photograph replacing a drawing of a conventional ITO film.

FIG. 8 is another photograph corresponding to FIG. 7;

FIG. 9 is an AFM replacing the drawing of the ITO film according to the present invention.
It is an image photograph.

FIG. 10 is another photograph corresponding to FIG. 9;

FIG. 11 is a TEM replacing a drawing of a conventional ITO film.
It is a photograph of an image and an electron diffraction image.

FIG. 12 is a photograph of a TEM image and an electron diffraction image instead of a drawing of an ITO film formed by the grid method of the present invention.

[Explanation of symbols]

 Reference Signs List 1 chamber 2 substrate 3 substrate holder 4 micro heater 5 crystal oscillation type film thickness monitor 6 coiled high frequency antenna 7 matching box 8 high frequency power supply 9 electron gun 10 mass flow controller 11 grid 12 D. C. Bias power supply 13 switch

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 14/00-14/58 C23C 16/00-16/56

Claims (8)

(57) [Claims] 1. A high-frequency plasma deposition apparatus for forming a high-frequency discharge plasma, with the evaporation source is provided, least one or more of the grid electrode is disposed in the vicinity of the substrate surface, and, Between the grid electrode and the evaporation source
A coiled high -frequency antenna is provided, a high-frequency power supply is connected to the grid electrode and the coiled high-frequency antenna , and plasma generated by application of a high-frequency voltage to the grid electrode and the coiled high-frequency antenna is used.
A high-frequency plasma film forming apparatus, wherein an evaporating substance evaporated from an evaporation source is excited to form a film on a substrate surface. 2. The high frequency plasma film forming apparatus according to claim 1, wherein a DC bias power supply is connected to the substrate. 3. The high frequency plasma film forming apparatus according to claim 1, wherein a high frequency power supply is connected to the substrate. 4. The grid electrode may be formed over the entire surface of the substrate.
It is claims 1 to face the part being arranged 3
Any of the high frequency plasma film forming apparatuses. 5. An entire surface opposite to the grid electrode.
5. The high-frequency plasma film forming apparatus according to claim 1 , wherein a shield covering at least a part thereof is detachably mounted . 6. A high frequency film formed by high frequency discharge plasma.
Microwave plasma film forming method, wherein
While disposing the film evaporating substance facing near the substrate surface,
Grid electrode connected to high frequency power supply
Arranged between the pole and the evaporation source and connected to a high frequency power supply
Discharge plug generated by a coiled high-frequency antenna
It is characterized in that the film is excited on the substrate and deposited on the substrate surface.
High-frequency plasma deposition how. 7. The method according to claim 1, wherein the film-forming evaporating substance is a metal, an inorganic substance,
7. The high-frequency plasma film forming method according to claim 6, comprising one or more types of equipment . 8. The method according to claim 6, wherein a conductive thin film is formed.
High frequency plasma film forming method .