JPH0778768A - Thin film forming device and method - Google Patents

Abstract

PURPOSE:Not only to form a thin film uniform and stable in thickness throughout the surface of a substrate but also to easily form a functional thin film. CONSTITUTION:Tunnel-like material guide paths 16a and 16b are provided so as to intersect each other at right angles, and the intersection is made to serve as a film forming chamber 14 wherein a substrate a on which a thin film is formed is housed. A suscepter 17 on which the substrate a is placed and a heater 13 which heats the substrate a are provided to the lower part of the film forming chamber 14. Material is fed to the film forming chamber 14 using alternately the material guide paths 16a and 16 but not fed through the guide guides 16a and 16b at the same time for the formation of a thin film on the substrate a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for forming a thin film on a substrate by applying a vaporized or atomized raw material to the surface of a heated substrate, and a method for forming a thin film using the apparatus.

[0002]

2. Description of the Related Art A transparent conductive film used in a solar cell, a liquid crystal display device, a plasma display device or the like and a resistive thin film used as a resistor of a circuit are formed of a metal oxide film.
This metal oxide film, for example, emits a mist of a raw material solution generated by an atomizer toward a heated substrate through a film-forming nozzle, and reacts and forms a film on the heated substrate. An example of an atomized thin film forming apparatus used when forming a metal oxide film by this method is shown in FIG.

In this apparatus, a tunnel-shaped raw material guiding path 6 is provided, and the central portion of the guiding path 6 is a film forming chamber 4 for accommodating a substrate a for forming a thin film. A susceptor 7 for mounting and holding the base body a is arranged below the film forming chamber 4, and under the susceptor 7, the base body a mounted thereon is placed.
Is provided with a heater 3 for heating. Raw material taxiway 6
A raw material supply device 1 for atomizing or vaporizing the raw material and supplying the same is connected to an upper surface side of one end side of the through a duct 2. Further, the other end of the guide path 6 is provided with a discharge port 5 for discharging the raw material which has passed through the film formation chamber 4 and was not consumed there for forming a thin film on the surface of the substrate a.

In this thin film forming apparatus, the substrate a housed in the film forming chamber 4 is heated to a predetermined temperature necessary for film formation by the heater 3 provided therebelow. Then, the atomized or gaseous raw material sent from the raw material feeder 1 side through the duct 2 and the guide path 6 comes into contact with the film forming surface of the substrate a in the film forming chamber 4,
For example, the raw material is decomposed by the heat possessed by the base a, and the decomposed raw material reacts with oxygen or the like in the air or solution to form a thin film such as an oxide on the film formation surface of the base a. Substrate a
The raw material that has not contributed to the formation of the thin film on the surface of is exhausted from the exhaust port 5. In the apparatus shown in FIG. 5, the mist of the raw material solution is supplied to the guide path 6 from the upper side, but an apparatus for supplying the mist or gaseous raw material to the guide path 6 from the lower side is also known. .

[0005]

When a metal oxide film is formed on the surface of a substrate 6 such as a glass plate in the above-mentioned conventional apparatus, the film thickness distribution of the thin film on the substrate a in the direction along the raw material supply direction. However, the film thickness distribution of the thin film in the direction orthogonal to the supply direction of the raw material is not constant, and the film thickness of the metal oxide film becomes non-uniform. this is,
The mist-like or gaseous raw material introduced from the duct 2 into the guideway 6 receives the flow path resistance on the wall surface of the guideway 6, and the flow rate near the center of the guideway 6 is large. This is because the flow rate of the raw material decreases on both sides.

When such a non-uniform state of the film thickness of the metal oxide film occurs, interference fringes appear on both sides of the substrate a, which is not preferable in appearance, and especially on both sides of the thin substrate a. However, the characteristics required for the metal oxide film cannot be obtained.
Therefore, at the time of use, it is necessary to remove both side portions of the base body a having a small film thickness.

For example, with respect to the film thickness of the central portion of the substrate a ±
When the parts on both sides where a difference in film thickness of 5% occurs are removed and used, when the tin oxide film is formed on the glass substrate by the conventional apparatus, the removal on this basis is based on the substrate a. It reaches about 30% of the effective film formation width. Therefore, only about 70% of the effective film-forming width of the substrate a can be actually used, and there is a drawback that the yield of products is poor. In view of the problems of the conventional thin film forming apparatus, an object of the present invention is to provide a thin film forming apparatus capable of forming a thin film having a uniform and stable film thickness over the entire width of a substrate.

[0008]

That is, according to the present invention,
In order to achieve the above-mentioned object, a film forming chamber 14 for accommodating a substrate a for forming a thin film, a heater 13 for heating the substrate a accommodated in the film forming chamber 14, a fog or a gas of a raw material solution, Raw material feeders 11a and 11b for supplying the atomized or vaporized raw material to the film forming chamber 14, and a discharge port 15a for discharging the raw material not consumed for thin film formation from the film forming chamber 14.
15b, the raw material supply devices 11a and 11b and the discharge port 1 are arranged so that the atomized or vaporized raw materials supplied to the film forming chamber 14 have different traveling directions.
There is provided a thin film forming apparatus characterized in that a plurality of 5a and 15b are provided.

In this case, the raw material feeder 11
From the a and 11b sides, through the film forming chamber 14, discharge ports 15a,
A plurality of material guide paths 16a, 16b leading to 15b are provided,
It is preferable that these are intersected and the film forming chamber 14 is provided at the intersection. Further, it is preferable to provide shutters 17a and 17b for blocking each of the guide paths 16a and 16b from the film forming chamber 14.

Further, according to the present invention, a base a for forming a thin film is formed.
, A heater 13 for heating the substrate a housed in the film forming chamber 14, a mist or gas of the raw material solution, and the atomized or vaporized raw material in the film forming chamber 14. Raw material feeders 11a and 11b for supplying, and a discharge port 15a for discharging raw material not consumed for thin film formation from the film forming chamber,
In the method of forming a thin film on a substrate a using a thin film forming apparatus having a raw material supply device 15b, raw material guiding paths 16a, 16b from the raw material supply devices 11a, 11b side to the discharge ports 15a, 15b through the film forming chamber 14. A plurality of them, and these are crossed in the film forming chamber 14, and each of these guide paths 16
The thin film forming method is characterized in that the thin film is formed on the substrate a by alternately supplying the raw materials from a and 16b to the film forming chamber 14 at the intersection.

[0011]

In the thin film forming apparatus of the present invention, the raw material feeders 11a and 11b and the discharge port 1 are arranged so that the atomized or vaporized raw materials supplied to the film forming chamber 14 have different traveling directions.
Since a plurality of 5a and 15b are provided, the film forming chamber 14
, The raw materials flow not only from one direction but from multiple directions. Therefore, unlike the case where the raw material is flowed from one direction to form the thin film, the thin film thickness is leveled and uniformed without unevenness in the thin film thickness at the opposite edge portions of the substrate a. A thin film having a film thickness can be formed. Further, since the raw materials having different components can be supplied from the respective induction paths 16a and 16b, the composition ratio of the components of the thin film can be easily controlled, and the functional thin film such as the resistance film can be formed.

A raw material guide path 1 from the material supply units 11a and 11b to the discharge ports 15a and 15b through the film forming chamber 14.
A plurality of 6a and 16b are provided, these are intersected, and the film forming chamber 14 is provided at the intersecting portion.
In the case where the shutters 17a and 17b for shutting off 6b from the film forming chamber 14 are provided, the film forming chamber 1 is connected to the guide paths 16a and 16b.
It is possible to cut off the raw material supplied to No. 4 at appropriate times and switch the flow direction of the raw material. Therefore, a plurality of taxiways 16
It is possible to prevent the raw materials from being simultaneously supplied to the film forming chamber 14 from a and 16b, and it becomes easy to control the flow direction of the raw materials, which is effective for forming the functional thin film as described above.

Further, in the thin film forming method of the present invention, the raw materials are alternately supplied to the film forming chamber 14 from the respective guiding paths 16a and 16b intersecting in the film forming chamber 14 to form a thin film on the substrate a. The raw materials are not simultaneously supplied to the film forming chamber 14 from the induction paths 16a and 16b. Thereby, the thin film can be formed in good condition on the substrate a without disturbing the flow of the raw material in the film forming chamber 14.

[0014]

Embodiments of the present invention will now be specifically described with reference to the drawings. The thin film forming apparatus according to the first embodiment of the present invention is shown in FIGS. In the apparatus according to this embodiment, two tunnel-shaped raw material guide paths 16a and 16b are provided, and these guide paths 16a and 16b are provided.
At the central portion thereof intersect at right angles, and the intersecting portion is a film forming chamber 14 for accommodating a base a for forming a thin film.

A susceptor 17 for mounting and holding a substrate a is arranged under the film forming chamber 4, and a heater 3 for heating the substrate a mounted thereon is provided under the susceptor 17. Raw material feeders 11a and 11b for supplying the raw material after atomizing or vaporizing the raw materials are connected to the upper surfaces of the raw material guide paths 6a and 16a through ducts 12a and 12b, respectively. Further, at the other ends of the guide paths 16a and 16b, a discharge port 15 for discharging the raw material that has passed through the film forming chamber 14 and was not consumed there to form a thin film on the surface of the substrate a.
a and 15b are provided.

In this thin film forming apparatus, the substrate a housed in the film forming chamber 14 is heated to a predetermined temperature required for film formation by the heater 3 provided therebelow. Then, the atomized or gaseous raw material sent from the raw material feeders 11a, 11b through the ducts 12a, 12b and the guide paths 16a, 16b comes into contact with the film-forming surface of the substrate a in the film-forming chamber 14, ,
The raw material is decomposed by the heat held by the base a, and the decomposed raw material reacts with oxygen in the air or the like to form a thin film of oxide or the like on the film forming surface of the base a. The raw materials that did not contribute to the formation of the thin film on the surface of the substrate a were exhaust ports 15a, 15
Exhausted from b.

Here, in the thin film forming method according to the present invention,
The raw materials are not sent to the film formation chamber 14 from the two guide paths 16a and 16b at the same time, but the raw materials are alternately sent. That is, the raw material feeders 11a and 11b are alternately operated so that each of the guideways 1
Raw materials are alternately sent to the film forming chamber 14 from 6a and 16b. As a result, the raw materials sent from the two guide paths 16a and 16b do not interfere with each other and are disturbed, and the raw materials flow in an orderly manner in the film forming chamber 14.

The graph of FIG. 6 shows a substrate a when a tin oxide film is formed as a thin film on the surface of a substrate a made of a glass plate by the thin film forming method according to the present invention using the apparatus shown in FIGS. 1 and 2. It shows the average film thickness at the position in the width direction. As a raw material, a 10 wt% aqueous solution of SnCl ₄ was used, and these were atomized by an ultrasonic atomizer to alternately form the film formation chambers 14 from two orthogonal guide paths 16a and 16b.
And a tin oxide thin film was formed on the glass substrate heated to 400 ° C. In this example, the film thickness of ± 5% with respect to the film thickness of the central portion of the substrate a was obtained in about 90% of the effective film formation width of the substrate a. On the other hand, using the conventional thin film forming apparatus shown in FIG. 5, the raw material is supplied to the film forming chamber 14 from only one direction,
When a tin oxide thin film was formed in the same manner, as shown in FIG. 6, a film thickness of ± 5% with respect to the film thickness of the central portion of the substrate a was obtained because of the effective film formation width of the substrate a. It was about 70%.

Next, the embodiment shown in FIGS. 3 and 4 will be described. In this embodiment, shutters 17a and 17b are provided to shut off the respective guiding paths 16a and 16b from the film forming chamber 14. That is, these shutters 17a, 17
b is provided in the front and rear portions of the film forming chamber 14 of each guide path 16a, and by closing it, the guide path 16a,
16b is shut off in the film forming chamber 14. FIG. 3 shows a case where the shutters 17a, 17a are closed, the guide path 16a is blocked, and the raw material is sent to the film forming chamber 14 only from the guide path 16b side. On the other hand, in FIG. 4, the shutters 17b and 17b are closed to shut off the guide path 16b, and the film forming chamber 1 is provided only from the guide path 16a side.
This is the case where the raw material is sent to No. 4.

According to this apparatus, the thin film forming method according to the present invention can be performed by operating the shutters 17a and 17b without depending on the operation control of the raw material feeders 11a and 11a. Moreover, it is possible to switch the flow quickly. In the above embodiment, the two guideways 16a, 1
6b is an example in which the film forming chamber 14 is made orthogonal to each other, but it is also possible to intersect three or more guide paths 16a and 16b, and the intersecting angle in the film forming chamber 14 is not limited to a right angle. Absent.

In addition to the thin film forming apparatus and the thin film forming method described above, a raw material supply unit and a discharge port are provided in the film forming chamber provided along the transfer path of the substrate a so that the advancing directions of the raw materials are different from each other. By providing a plurality of thin films, a thin film having a uniform film thickness can be obtained as in the above-described embodiment.

Further, in the thin film forming apparatus shown in FIGS. 1 and 2 described above, by flowing raw materials of different components through the respective induction paths 16a and 16b, a thin film having a property different from the conventional one can be formed on the substrate a. Can be formed. For example, by flowing a mist of a 10 wt% aqueous solution of SnCl _{4 through} one induction path 16a and a mist of a 10% by weight aqueous solution of FnCl ₄ through the other induction path 16b, the electrical resistance value of the thin film is increased. A thin film that can be used as a thin film resistor can be formed. Needless to say, even with the thin film thus formed, the film thickness can be made uniform as described above.

[0023]

As described above, according to the present invention, it is possible to form a thin film having a uniform and stable film thickness over the entire width of the substrate by reducing the difference in film thickness between the central portion and both side portions of the substrate. Therefore, it is possible to increase the ratio to the width capable of obtaining a thin film having a usable film thickness with respect to the effective film forming width of the substrate. This makes it possible to improve the yield of thin film formation. Further, by supplying raw materials having different components from the respective induction paths 16a and 16b, it becomes possible to form a functional thin film such as a resistance film.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional side view of a thin film forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic perspective view of a thin film forming apparatus according to the same embodiment.

FIG. 3 is a schematic perspective view of the thin film forming apparatus according to the second embodiment of the present invention with one shutter closed.

FIG. 4 is a schematic perspective view of the thin film forming apparatus according to the embodiment with the other shutter closed.

FIG. 5 is a schematic vertical sectional side view of a thin film forming apparatus according to a conventional example.

FIG. 6 is a graph showing the average film thickness in the width direction of a substrate for a thin film formed by a thin film forming method according to an example of the present invention and a thin film formed for a comparative example.

[Explanation of symbols]

 11a raw material supply device 11b raw material supply device 13 heater 14 film forming chamber 15a discharge port 15b discharge port 16a guide path 16b guide path 17a shutter 17b shutter a substrate

Claims (4)

[Reference number] 0050178-01 [Claims] 1. A film forming chamber (14) for accommodating a substrate (a) for forming a thin film, a heater (13) for heating the substrate (a) accommodated in the film forming chamber (14), and a raw material solution. Raw material feeders (11a), (11) for generating mist or gas and supplying the atomized or vaporized raw material to the film forming chamber (14).
b) and the raw material not consumed for thin film formation in the film forming chamber (1
In a thin film forming apparatus having discharge ports (15a) and (15b) for discharging from 4), raw material supply is performed so that the atomized or vaporized raw materials supplied to the film forming chamber (14) have different traveling directions. A thin film forming apparatus comprising a plurality of vessels (11a) and (11b) and a plurality of discharge ports (15a) and (15b). 2. The raw material feeder (1) according to claim 1,
1a), (11b) side through the film forming chamber (14) to the discharge ports (15a), (15b) of the raw material guide path (16)
A thin film forming apparatus characterized in that a) and a plurality of (16b) are provided, and these are intersected and the film forming chamber (14) is provided at the intersection. 3. The thin film forming apparatus according to claim 2, further comprising shutters (17a) and (17b) for blocking each of the guide paths (16a) and (16b) from the film forming chamber (14). 4. A film forming chamber (14) for accommodating a substrate (a) for forming a thin film, a heater (13) for heating the substrate (a) accommodated in the film forming chamber (14), and a raw material solution. Raw material feeders (11a), (11) for generating mist or gas and supplying the atomized or vaporized raw material to the film forming chamber (14).
b) and the raw material not consumed for thin film formation in the film forming chamber (1
4) A method for forming a thin film on a substrate (a) using a thin film forming apparatus having discharge ports (15a) and (15b) for discharging from the raw material supply devices (11a) and (11b). Outlet (15a), (1
5b) is provided with a plurality of raw material guideways (16a) and (16b), and from these respective guideways (16a) and (16b),
A method for forming a thin film, characterized in that a raw material is alternately supplied to a film forming chamber (14) at the intersection to form a thin film on a substrate (a).