JPH08306626A - Substrate heating equipment and film forming equipment - Google Patents

Abstract

PURPOSE: To uniformly neat a substrate by simple constitution, and form a thin film of uniform thickness. CONSTITUTION: On a mounting stand 14 in a cabinet 12, a substrate 15 is so mounted that the surface of a substrate 15 comes into contact with a mounting surface. From a reaction gas feeding nozzle 13, reaction gas containing thin film material is supplied to the inside of the cabinet 12. By heating the substrate 15, a thin film is formed on the substrate 15. In the mounting stand 14, a space 17 wherein the size of an upper inner wall surface 17a is nearly equal to that of the mounting surface is formed. High thermal conductivity gas heated by a gas heating means 20 is supplied to the space 17 through a tube 18, and the substrate mounting surface of the mounting stand 14 is uniformly heated. The heat is conducted to the substrate 15 on the mounting stand 14, and the substrate 15 is uniformly heated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film forming apparatus using a chemical vapor deposition method and a substrate heating apparatus suitable for use in the apparatus.

[0002]

2. Description of the Related Art Conventionally, as a method for forming a semiconductor or metal thin film on a glass or silicon substrate, there is, for example, a chemical vapor deposition (hereinafter abbreviated as "CVD") method. CV
In the D method, a substrate on which a thin film is to be formed is placed in a space filled with a reaction gas containing a thin film material, and thermal energy is applied to the reaction gas. This causes a chemical reaction in the thin film material to deposit a thin film on the substrate. The thermal energy is provided, for example, by heating the substrate. Therefore, it is necessary to heat the substrate on which a thin film is to be formed to a predetermined temperature in a thin film forming apparatus such as a CVD method.

FIG. 4 is a perspective view of a mounting table 1 of a substrate heating apparatus used in a conventional thin film forming apparatus. A substrate to be heated is placed on the mounting table 1, and a linear resistor 2 that is a heating means for heating the mounted substrate is bent and embedded inside the mounting table 1. . The resistor 2 is arranged on almost the entire mounting surface of the mounting table 1.
When forming a thin film on the substrate, the substrate is placed on the placement surface of the placing table 1, and a current of a predetermined magnitude is applied to the resistor 2 to generate Joule heat. The substrate is heated by this Joule heat.

FIG. 5 is a perspective view of a mounting table 6 of another substrate heating apparatus used in the conventional thin film forming apparatus. In this conventional technique, a plurality of infrared sources 7 are arranged above the mounting table 6 as heating means. The infrared source 7 is
Four positions, for example, are arranged at positions where the surface of the substrate 8 arranged on the mounting table 6 can be irradiated, for example, at positions deviating from just above the mounting table 6 and in parallel with four sides of the plate-shaped mounting table 6. . Do not place the infrared source 7 directly above the mounting table,
This is so as not to obstruct the reaction gas supply nozzle and the like arranged immediately above. When forming a thin film on a substrate, the substrate 8 is placed on the mounting table 6 and the surface of the substrate 8 is irradiated with infrared rays 9 generated from the infrared source 7.
The substrate 8 is heated by the radiant heat of the infrared rays 9.

When a substrate is heated in a thin film deposition apparatus equipped with such a substrate heating device, if the temperature of the substrate surface varies, the growth rate of the thin film deposited on the substrate varies. As a result, the film thickness of a thin film formed within a certain period of time may vary, and a thin film having an uneven film thickness may be formed on the substrate. In particular, when the size of the substrate becomes large, for example, in the substrate heating apparatus shown in FIG. 5, the difference between the distance between the infrared source 7 and the central portion of the substrate 8 to be heated and the distance between the infrared source 7 and the peripheral portion of the substrate 8 are growing. As a result, it becomes difficult to uniformly heat the entire surface of the substrate, and thus the thickness of the thin film formed on the substrate becomes uneven.

The variation in the thickness of the thin film causes a reduction in the yield of products using this thin film. For example, when a semiconductor film of a thin film transistor is formed by using a thin film forming apparatus equipped with the above-described substrate heating device and the film thickness of the film varies, the current flowing through the drain electrode is changed as shown in the following equation. It changes according to the film thickness.

Id = μ ・ Ci ・ W ・ Vg ・ Vd / L
+ W · d · Vd / (ρ · L) Id is a current flowing through the drain electrode. μ is the charge mobility. Ci is the capacitance per unit area of the insulating film in the thin film transistor. L is the channel length. W
Is the channel width. ρ is the resistivity of the semiconductor film. d is the film thickness of the semiconductor film. Vg is a voltage applied to the gate electrode. Vd is a voltage applied to the drain electrode.

As described above, the current flowing through the drain electrode increases in proportion to the film thickness of the semiconductor film. For example, when a large number of thin film transistors are formed on a substrate such as a substrate member of a liquid crystal display device, semiconductor films of a large number of thin film transistors are often formed by dividing one thin film formed over the entire surface of the substrate. When the film thickness of this one thin film is not uniform, the film thickness of the semiconductor film of each thin film transistor varies. As a result, the current flowing through the drain electrode of each thin film transistor varies. Therefore,
There is a problem that the display quality of a liquid crystal display device using this substrate member is degraded.

In order to prevent such variations in the thin film, for example, in the substrate heating apparatus shown in FIG. 5, the distance between the infrared source and each portion of the substrate is adjusted by rotating the mounting table,
I try not to overheat only a part.

[0010]

As described above, the larger the size of the substrate, the more difficult it is to uniformly heat the substrate. Therefore, the film thickness of the thin film formed on the substrate varies, and the yield of products using this thin film decreases.

For example, in the substrate heating apparatus using the resistor 2 shown in FIG. 4, when it is attempted to uniformly heat the substrate, the resistors 2 in the mounting table 1 are arranged in a dense arrangement, or a current is applied to the resistor 2. Need to be finely controlled. Also, the resistor 2
Since it is possible that an electrical short circuit occurs between the resistors 2 if the arrangement of the resistors is made dense, it is necessary to insulate the resistors 2 from each other. Furthermore, in the substrate heating device using the infrared source 7 shown in FIG. 5, in order to uniformly heat the substrate 8,
It is necessary to adjust the distance between the substrate and the infrared source 7 by rotating the mounting table 6 on which the substrate 8 is mounted with respect to the infrared source 7, and an apparatus for this purpose needs to be added to the mounting table 6.

For these reasons, the structure of the mounting table provided with the heating means of the substrate heating apparatus becomes complicated. Therefore, the manufacturing cost for the substrate heating apparatus and the film forming apparatus increases. Moreover, the control for uniformly heating the substrate becomes complicated. Furthermore, since the structure becomes complicated, there is a problem that maintenance of the device becomes difficult.

It is an object of the present invention to provide a substrate heating device having a simple structure and capable of uniformly heating a substrate, and a film forming device capable of forming a thin film having a uniform film thickness. Is.

[0014]

According to the present invention, there is provided a mounting means for mounting a substrate to be heated, having a mounting surface larger than the surface of the substrate, and having at least one space inside.
A substrate heating apparatus comprising: a gas heating means for heating a gas to a predetermined temperature; and a gas supply means for supplying the gas heated by the gas heating means into the space of the placing means. Further, the upper inner wall surface inside the placing means of the present invention is substantially the same size as the placing surface. Further, the space of the placing means of the present invention communicates with a plurality of column-shaped first spaces formed on the mounting surface side, and is formed on the side opposite to the mounting surface side. It is characterized in that it is composed of a second space. The placing means of the present invention is characterized in that it is made of a material having a high thermal conductivity. Further, the gas of the present invention is characterized by having a high thermal conductivity. Further, the present invention is a mounting means for mounting a substrate on which a film is to be formed, having a mounting surface larger than the surface of the substrate, and having at least one space inside.
From the gas heating means for heating the gas to a predetermined temperature, the gas supply means for supplying the gas heated by the gas heating means into the space of the above-mentioned placing means, and the nozzle arranged above the placing means. A reaction gas supply means for supplying a reaction gas containing a film material, a housing for accommodating the nozzles of the placing means and the reaction gas supply means, and a housing filled with the reaction gas from the reaction gas supply means, and the housing. And a gas exhaust unit for exhausting the gas.

[0015]

According to the present invention, the substrate heating device places the substrate to be heated in contact with the placing surface on the placing means having at least one space inside, and the space in the placing means is described. To
The gas heated by the gas heating means to a predetermined temperature is supplied by using the gas supply means to heat the mounting means. The heated heat of the placing means is transferred to the substrate to heat the substrate. The supplied gas spreads to every corner of the space, whereby the mounting means is heated uniformly, so that the substrate mounted on the mounting surface is also heated uniformly. Therefore, it is not necessary to rotate the substrate with respect to the heating means, and the substrate can be heated easily and uniformly.

Further, according to the invention, the upper inner wall surface inside the placing means is formed to have substantially the same size as the placing surface and to cover the surface of the substrate placed on the placing means. ing. As a result, the entire surface of the substrate comes into contact with the mounting surface heated to the same temperature. Therefore, the substrate can be heated more uniformly.

Further, according to the invention, the space communicates with a plurality of columnar first spaces formed on the mounting surface side, and communicates with the plurality of first spaces, and the surface side opposite to the mounting surface side. And a second space formed in. The supplied gas travels through the second space to the plurality of first spaces to heat the mounting means. By selecting the arrangement of the plurality of first spaces, the entire surface of the substrate can be heated uniformly.

According to the invention, the placing means is made of a material having high thermal conductivity. Furthermore, according to the present invention, the gas supplied to the space in the placing means is a gas having a high thermal conductivity. As a result, the gas is easily heated, and the heat of the gas is quickly transferred to the mounting means. Thereby, the mounting means can be heated easily and uniformly. Further, even if the area of the placing means on which the substrate is placed is enlarged, the placing means in the area can be heated easily and uniformly.

Furthermore, according to the present invention, a film forming apparatus is configured to include the substrate heating device. In the housing, the placing means and the nozzle placed on the placing means are housed. The apparatus places a substrate on which a thin film is to be formed on the placing means, heats the substrate in the same manner as described above, and supplies the inside of a reaction gas containing a film material from the nozzle, Form a thin film on a substrate. The reaction gas supplied into the housing is exhausted by the exhaust means. Since the film forming apparatus includes the above-mentioned substrate heating device, the substrate placed on the placing means can be uniformly heated. The growth rate of the thin film formed on the substrate depends on the temperature of the substrate at the position where the thin film is formed. In the film forming apparatus, since the substrate is heated uniformly, it is possible to make the film thickness of the thin film formed on the substrate uniform.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of a thin film forming apparatus 11 which is an embodiment of the present invention. FIG. 2 is a perspective view of the mounting table 14 of the thin film deposition apparatus of FIG. The thin film deposition apparatus 11 is a thin film deposition apparatus that deposits a thin film on a substrate by using, for example, a CVD method.

In the thin film forming apparatus 11, the reaction gas containing the thin film material is introduced into the housing 12 from the reaction gas supply nozzle 13 introduced into the housing 12. An end portion of the nozzle 13 inside the housing 12 is processed into a flat plate shape having a surface having substantially the same area as the mounting table 14, and a plurality of holes 13 a provided in the flat plate portion toward the mounting table 14 are provided. The reaction gas spouts from. A mounting table 14 is provided in the housing 12, and the mounting surface of the substrate 15 on which the thin film is to be deposited is opposite to the surface on which the thin film is formed. Placed. The mounting surface of the mounting table 14 is the substrate 1
5 is chosen to be a larger area than the surface. A region of the mounting table 14 on which the substrate 15 is mounted is located immediately below the reaction gas supply nozzle 13 and the flat end portion. Below the housing 12, an exhaust hole 16 connected to a valve or pump not shown
Is formed.

The mounting table 14 is, for example, a thick plate-shaped member, and a space 17 is formed therein.
The upper inner wall surface 17a inside the space 17 is the mounting table 14
It is selected to have almost the same area as the mounting surface. The substrate 15 is placed on the area where the space 17 is formed.

A tube 18 is connected to the mounting table 14 on the surface opposite to the mounting surface. By the pipe 18, the space 1
7 is connected to a gas supply means 19 and a gas heating means 20 provided outside the housing 12. The space 1
7, a gas supply means 19 is used for the gas heating means 20.
The heating gas heated by is supplied. Gas supply means 1
9 is realized by, for example, a pump or the like.

Argon, helium, nitrogen or the like is used as the heating gas. As described above, a gas having a relatively high thermal conductivity is used as the heating gas. Further, the mounting table 14 is realized by a material having a relatively high thermal conductivity and capable of precision processing, such as alumina or aluminum nitride. Particularly, it is preferable to use helium gas having high thermal conductivity as the heating gas and aluminum nitride as the material of the mounting table 14.

When a thin film is formed on the substrate 15 using the thin film forming apparatus 11, first, the mounting table 14 in the housing 12 is used.
The substrate 15 is placed on the substrate, and the gas in the housing 12 is exhausted to a predetermined degree of vacuum. Then, a reaction gas containing a thin film material is introduced into the housing 12 from the reaction gas supply nozzle 13 to keep the inside of the housing 12 at a predetermined pressure.

Then, the heating gas heated to a predetermined temperature is introduced into the space 17 of the mounting table 14. Since the space 17 inside the mounting table 14 is filled with the gas heated to a predetermined temperature without any gaps, the mounting wall 14 has an upper wall surface 17 a inside the space 17, that is, a region in contact with the surface of the substrate 15. The entire placement surface is heated uniformly. As a result, the heat of the mounting table 14 is transferred to the substrate 15 mounted on the mounting table 14 and heated to a predetermined temperature. The thin film material in the reaction gas causes a chemical reaction on the substrate surface by the heat of the substrate 15, and the thin film material is deposited on the surface of the substrate 15 to form a thin film. In order to keep the temperature of the substrate 15 constant while the thin film is formed, two pipes are connected to the space 17 so that gas is supplied from one pipe and discharged from the other pipe.
The heated gas supplied to the space 17 may be circulated to constantly supply the high temperature gas to the space 17. Alternatively, the inner diameter of the tube 18 may be increased to supply a large amount of heated gas to the space 17.

Next, the pressure in the housing 12 is returned to atmospheric pressure,
After the reaction gas is discharged from the exhaust hole 16 of the housing 12, the substrate 15 on which the thin film is formed is taken out from the housing 12. When the thin film forming step is subsequently repeated, the work of newly mounting the substrate 15 on the mounting table 14 and again forming a thin film on the same substrate 15 is repeated.

To reheat the mounting table 14 which has been heated once, the heating gas already filled in the space 17 is supplied to the tube 18
After being discharged from the outside to the outside, the space 17 is filled with the newly heated heating gas through the pipe 18. It is assumed that the newly heated gas is filled after the substrate 15 is placed in the housing 12 and the gas in the housing 12 is exhausted to a predetermined vacuum degree. In this way, the heated gas is placed on the mounting table 14
By supplying the entire surface of the space 17 densely,
The substrate 15 on 4 can be heated. Since the heated gas is pressurized and supplied in a large amount to the space 17, it is possible to uniformly supply heat energy to the entire mounting surface of the mounting table 14. Therefore, the temperature difference generated in the substrate 15 placed on the placing surface and to which the heat of the placing surface is transferred can be made extremely small as compared with the conventional technique. Further, since the space 17 is pressurized by the heated gas, it is possible to prevent the mounting surface of the mounting table 14 from bending.

FIG. 3 is a perspective view of a mounting table 14a used in a thin film forming apparatus according to another embodiment of the present invention. The thin film deposition apparatus of the present embodiment has a configuration similar to that of the thin film deposition apparatus 11 of the above embodiment, except that a mounting table 14a as shown in FIG. It is constructed in the same manner as the membrane device 11. The mounting table 14a has a configuration similar to that of the mounting table 14 shown in FIG. 2, and the same components are designated by the same reference numerals and description thereof will be omitted.

In the present embodiment, the space 22 formed in the mounting table 14a is divided into a plurality of spaces 22a on the mounting surface side on which the substrate is mounted and a surface opposite to the mounting surface side. It is divided into the formed rectangular spaces 22b. The divided space 22a is realized by a plurality of columnar spaces, for example, columnar spaces, arranged in a matrix on almost the entire mounting surface. The cylindrical space is formed so that a cylinder extends in a direction perpendicular to the mounting surface. The cylindrical space of the space 22a communicates with the space 22b on the opposite side of the mounting surface. The space 22b is formed to have the same size as the space 17 and is connected to the gas supply means 19 and the gas heating means 20 through the pipe 18. In this way, the space 22 provided in the mounting table 14a and filled with the heating gas
Has a space on the mounting surface side divided into a plurality of spaces. At this time, the divided areas are arranged at intervals so as not to cause temperature variations on the mounting table surface. For example, the space 22a
Reduces the area of the cross section parallel to the mounting surface,
It is preferable to provide a large number in a.

In the thin film deposition apparatus having such a mounting table 14a, the spaces 22a and 22b provided in the mounting table 14a on which the substrate 15 is mounted are filled with a heating gas heated to a predetermined temperature. By doing so, the surface of the mounting table 14 is heated, and the heat of the surface of the mounting table 14a is propagated to the substrate 15 mounted thereon to heat the substrate 15. As described above, the space 22a formed on the mounting surface side in the mounting table 14a may be formed to have substantially the same size as the mounting surface. That is, a space having a size that covers the surface of the substrate mounted on the mounting table 14a may be formed into a plurality of divided shapes.

In a substrate heating apparatus for heating a relatively large substrate, the mounting table of the present embodiment in which the space is divided into a plurality of spaces as compared with the mounting table 14 having a single space 17 as shown in FIG. Since the mounting surface of the mounting table 14a is supported by the portion in which the columnar space 22a is not formed, the mounting table 14a when the space 22 is not supplied with gas and pressure is not applied thereto. It is possible to further prevent the distortion and the flexure of the mounting surface.

Spaces 22a, 22b to the mounting table 14a
Is formed as follows. For example, when the mounting table is mounted on a flat plate of alumina or aluminum nitride that can be precisely processed and has a relatively high thermal conductivity, the pipe 18
From the side where is attached, a plurality of columnar holes to be the space 22a are provided using a drilling tool such as a drill. Then, the opening side of the hole of the flat plate is excavated to provide a rectangular excavation portion which becomes the space 22b, and the opening portion of the excavation portion is closed except for the portion connecting to the pipe 18. As a result, the mounting table 14a shown in FIG. 3 is obtained.

In the substrate heating apparatus provided in the thin film deposition apparatus of the above-described two embodiments, the mounting tables 14 and 14a are provided with the spaces 17 and 22, and the heated gas is supplied to the spaces 17 and 22. The substrate 15 can be heated. As described above, the structure of the mounting table is simpler than that of the mounting table of the related art. That is, it is not necessary to install a resistor or the like in the mounting table, and a failure of the heating device due to disconnection of the resistor does not occur.

Further, in the substrate heating apparatus, the space 1 is provided on substantially the entire mounting surfaces of the mounting tables 14 and 14a on which the substrates are mounted.
7 and 22 exist, and the entire surface of the substrate is heated uniformly at the same time.
This eliminates the need for rotating the substrate with respect to a fixed heating source and providing a rotating device that requires frequent maintenance unlike the conventional heating device. Therefore, a malfunction such as a malfunction of the rotating device does not occur, and the malfunction of the substrate heating device can be reduced. Therefore, the frequency of maintenance can be reduced.

[0036]

As described above, according to the present invention, the substrate heating apparatus mounts the substrate to be heated on the mounting means having at least one space therein and stores the heated gas in the space. By supplying, the placing means is heated uniformly, and the substrate placed on the placing means is heated. In addition, the upper inner wall surface in the space is formed to have a size substantially the same as the mounting surface and to cover the surface of the substrate mounted on the mounting means. The space is composed of a plurality of first spaces on the mounting surface side and a second space that communicates with the first space on the side opposite to the mounting surface side. With these, even with a relatively large-sized substrate, the substrate temperature can be uniformly heated over the entire surface of the substrate using a heating device having a simple structure. As described above, the structure of the heating device is simplified as compared with the conventional heating device, so that the number of failures of the heating device can be reduced. This facilitates maintenance of the heating device and reduces the frequency of maintenance.

Further, according to the present invention, the film forming apparatus heats the substrate by the substrate heating apparatus, and reacts the reaction gas supplied into the housing containing the mounting means of the substrate heating apparatus to react the reaction gas on the substrate. Form a thin film. Since the substrate is uniformly heated by the substrate heating device, the thickness of the thin film formed on the substrate can be kept constant. As a result, the yield of products manufactured using the substrate on which a thin film is formed, for example, thin film transistors, can be improved.

Furthermore, according to the present invention, the gas has high thermal conductivity, and the mounting means also has high thermal conductivity. As a result, the surface of the mounting means can be easily heated uniformly by the heat given to the gas.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a thin film deposition apparatus 11 that is an embodiment of the present invention.

FIG. 2 is a perspective view of a mounting table 14 of FIG.

FIG. 3 is a perspective view of a mounting table 14a used in a thin film deposition apparatus that is another embodiment of the present invention.

FIG. 4 is a perspective view of a mounting table 1 of a conventional thin film deposition apparatus.

FIG. 5 is a perspective view of a mounting table 6 including an infrared source 7 of a conventional thin film deposition apparatus.

[Explanation of symbols]

 Reference Signs List 11 thin film deposition apparatus 12 housing 13 reaction gas supply nozzle 14, 14a mounting table 15 substrate 16 exhaust holes 17, 22, 22a, 22b space 17a upper inner wall surface 18 tube 19 gas supply means 20 gas heating means

Claims (6)

[Claims] 1. A mounting means for mounting a substrate to be heated, having a mounting surface larger than the surface of the substrate, and having at least one space therein, and a gas for heating gas to a predetermined temperature. A substrate heating apparatus comprising: a heating means; and a gas supply means for supplying the gas heated by the gas heating means into the space of the placing means. 2. The upper inner wall surface inside the mounting means is substantially the same size as the mounting surface.
The substrate heating device described. 3. The space of the mounting means communicates with a plurality of columnar first spaces formed on the mounting surface side, and is formed on the side opposite to the mounting surface side. 2. The substrate heating apparatus according to claim 1, wherein the substrate heating apparatus comprises: 4. The substrate heating apparatus according to claim 1, wherein the placing means is formed of a material having high thermal conductivity. 5. The substrate heating apparatus according to claim 1, wherein the gas has a high thermal conductivity. 6. A substrate on which a film is to be formed is placed, has a placement surface larger than the surface of the substrate, and has at least one inside thereof.
A mounting means having two spaces, a gas heating means for heating the gas to a predetermined temperature, a gas supply means for supplying the gas heated by the gas heating means into the space of the mounting means, A reaction gas supply means for supplying a reaction gas containing a film material from a nozzle arranged in the upper part of the means, and a nozzle of the placement means and the reaction gas supply means are housed,
A film forming apparatus comprising: a housing filled with the reaction gas from the reaction gas supply means, and an exhaust means for exhausting the gas in the housing.