JP2000045072A - Film forming apparatus, method and film forming product - Google Patents

Abstract

(57) Abstract: A diamond film is formed on a substrate by a simple process without bending the substrate. A substrate (10) is provided at a center position of a vacuum chamber (1).
Are fixed to the substrate holder 3 with both surfaces exposed. The vacuum chamber 1 has a left-right configuration centered on the substrate 10, and simultaneously supplies radicals of a source gas to the right side of the substrate 10 on the left side under the same conditions to form a diamond film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a technique for forming a film of diamond or the like.

[0002]

2. Description of the Related Art A diamond film formed on a substrate is used for various purposes such as a heat sink or heat spreader for a semiconductor device, a SAW (surface acoustic wave) device, a pressure-resistant disk, a disk protective film, an X-ray window, and the like. It's being used. As a method of forming a diamond film, a hot filament method and various plasma CVD methods (RF (high frequency), ECR (Electron Cycrotron Resonance), microwave, DC arc method, etc.) are known.

The common point of these conventional film forming methods is that the substrate is fixed on a stage, the substrate is brought into close contact with the stage, and the substrate is cooled or heated from the stage to control the substrate at an optimum temperature for film formation. The point is that a diamond film is formed on the surface of the substrate. According to this conventional method, a diamond film is formed only on one side of the substrate. However, due to the stress caused by the difference in lattice constant between the diamond film and the substrate, and the stress caused by the difference in thermal expansion coefficient between the diamond film and the substrate,
In addition, due to the difference in elastic modulus between the diamond film and the substrate, the substrate usually has a characteristic of being more easily bent than the diamond film, so that a phenomenon occurs in which the substrate is curved.

[0004] More specifically, diamond is known as the hardest material among solid materials, and is a material having a large elastic modulus, that is, a material having small elongation and strain when subjected to the same magnitude of stress. In a normal film formation process, the force generated between the substrate and the film is dispersed in the thickness direction of the substrate and is applied per unit area of the cross section of the substrate because the substrate is significantly thicker than the thin film on the substrate. The force (stress) is much smaller than that of the film, and as a result, the film relatively expands and contracts. On the other hand, in the case of a diamond film, the elastic modulus is larger than that of the substrate material, and furthermore, in particular, in the case of a heat sink or a heat spreader, the substrate has a thickness that is difficult to be considered as a sub-millimeter-thick film. It is.

[0005] The temperature condition of the substrate when forming a diamond film is as high as 600 to 1200 ° C, and the temperature of the diamond film is lowered from the film formation temperature to room temperature due to the difference in linear expansion coefficient between the diamond and the substrate material. The stress generated at the interface between the substrate and the substrate increases, and the diamond film placed on the substrate causes the substrate to bend. Then, since the support condition between the substrate and the stage changes, the heat transfer condition from the substrate to the stage changes, and the temperature condition of the substrate changes during the film formation. As a result, a uniform diamond film cannot be formed in the depth direction of the diamond film, or a local load is easily applied in a step of polishing the diamond film later, and the substrate is cracked or uneven polishing occurs. Such a problem arises.

In order to solve this problem, Japanese Patent Laid-Open Publication No. Hei 7-21
No. 5796 discloses a method of reducing stress by alternately depositing diamond films having different characteristics under two or more kinds of film formation conditions. Japanese Patent Application Laid-Open No. 7-243044 discloses that when a substrate starts to bend during diamond film formation, the substrate is taken out, the surface of the substrate opposite to the surface on which the diamond film is formed is polished and flattened, and then the film is formed again. Is disclosed. Japanese Patent Application Laid-Open No. 8-195367 discloses the use of a substrate having a warped shape in advance, and the use of a polishing machine in which a substrate holder can be inclined during polishing.

[0007]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open No. 7-2
No. 15796, a method of changing film forming conditions,
The method of taking out a substrate in the middle of the film formation described in JP-A-43044 requires a complicated process, which lowers the throughput, and requires an advanced control device to optimize the film formation conditions. In the method of using a warped substrate disclosed in Japanese Patent Application Laid-Open No. 8-195367, the degree of curvature that varies depending on the material and thickness of the substrate and the film is bothersome. Requires a special polishing machine.

Accordingly, it is an object of the present invention to form a film such as diamond on a substrate by a simple process without curving the substrate.

[0009]

According to the present invention, a film of a predetermined substance such as diamond is formed on both surfaces of a substrate by using film forming units arranged on both sides of the substrate.

Preferably, films having the same thickness are formed on both sides of the substrate simultaneously and under the same conditions.

When the two-sided film formation is performed in this manner, the forces generated due to the difference in lattice constant and the difference in the coefficient of thermal expansion between the film and the substrate are the same on both sides of the substrate and opposite to each other. Both are offset. As a result, a substrate with a film having less curvature can be obtained. During the film formation, there is no need to change the film formation conditions or to perform a troublesome operation such as taking out and flattening the back surface. In addition, since the curvature of the substrate is small, the change in the transfer condition of the substrate to the support and the continuous change during the deposition of the substrate temperature condition are small, and as a result, the quality is more uniform in the depth direction of the film. Can be formed. The substrate with a film obtained in this manner has a lattice constant of the substrate,
Since the difference in elastic modulus is maintained and the curvature is extremely small, a uniform surface load can be applied to the polished surface even when using a ready-made polishing machine in a polishing process which is a post-process of film formation. Therefore, cracking of the board caused by local concentration of surface load,
Polishing unevenness can be avoided, and the yield in the polishing step can be improved.

The film forming technique of the present invention is particularly suitable for forming a diamond film, but is not limited thereto. When a diamond film is formed, Si, SiC, Mo, Al2O3, AlN, W, Ti, S
Various things such as US can be used.

The present invention also provides a product utilizing a diamond film using a substrate having a diamond film formed on both surfaces.

[0014]

FIG. 1 shows a structure of a microwave plasma CVD apparatus according to an embodiment of the present invention, and FIG. 2 shows a structure of a substrate holder of the apparatus in FIG.

As shown in FIG. 1, a substrate holder 3 is disposed at a central position in a vacuum chamber 1. This substrate holder 3
Then, a plurality of substrates 10 on which a film is to be formed are fixed.
The vacuum chamber 1 includes a substrate 10 fixed to a substrate holder 3.
A right side chamber 1a for forming a diamond film on a right side 10a in FIG.
0b for forming a diamond film. These two chamber parts 1a,
1b are configured to be symmetric with respect to the substrate holder 3. This means that both sides 10a of the substrate 10
This is effective for forming a film evenly on 10b.

Each of the two chambers 1a, 1b has a vacuum pump 2a, 2b for evacuating each of the chambers 1a, 1b, and a plasma gas and a raw material gas of diamond are introduced into each of the chambers 1a, 1b. Inlets 6a and 6b for generating a microwave for converting the introduced gas into plasma.
b, microwave waveguides 8a and 8b for introducing the microwave into each of the chamber portions 1a and 1b, and a microwave resonance plate 9a for reflecting the microwave to generate resonance,
9b, and a high-frequency coil 11 arranged to surround the substrate holder 3 and heat the substrate 10 fixed to the substrate holder 3. Further, each of the chamber portions 1a, 1b
The substrate observation windows 12a, 12b and the windows 12
Radiation thermometers (pyrometers) 13a and 13b for monitoring the substrate temperature through a and 12b are also provided.

As shown in FIG. 2, the substrate holder 3 has a cooling water pipe 4 having a cooling water introduction port 4 and a cooling water discharge port 5, and a pipe frame 14 formed in a lattice shape. Pipe frame 14 to be surrounded
A plurality of board mounting plates 15 in the form of a square frame fixed to
And Each board mounting plate 15 has one board 1
0 can be fixed, and both surfaces of the substrate 10 fixed thereon are exposed in the left and right chamber portions 1a and 1b, respectively.

At the time of film formation, the left and right chamber portions 1a, 1b
At the same time and under the same conditions, the plasma gas and the raw material gas are excited by microwave energy to form plasmas 16a and 16b of those gases near both surfaces 10a and 10b of the substrate 10, whereby the raw material gas Is radicalized, and radicals of the raw material adhere to both surfaces 10a and 10b of the substrate 10. During this film formation, the substrate 10 is maintained at a temperature suitable for diamond film formation by the cooling water flowing through the pipe frame 14 of the substrate holder 3 and the substrate heating high-frequency coil 11. As a result, a diamond film is uniformly formed on both surfaces 10a and 10b of the substrate 10.

Using this embodiment, a film forming test was performed as follows. After the substrate 10 is scratched on both sides under the same conditions, the substrate 10 is mounted on the substrate holder 3 and cooled with 1 SLM of cooling water (20 ° C.,
(1 atm, 1 liter / min) was introduced from the cooling water inlet 4 and drained from the cooling water outlet 5. As the substrate 10, a silicon wafer having a thickness of 0.5 mm and a plane size of 20 mm × 20 mm was used. In the scratching process, SiC # 3000
Lap polishing was performed using the above abrasive grains. Vacuum pumps 2a, 2
b to operate the inside of the vacuum chamber 1 at a vacuum degree of 0.001 torr.
Then, the degree of vacuum was maintained while operating the vacuum pumps 2a and 2b. In addition, high-frequency coil 1 for substrate heating
Power was applied to 1 and the temperatures of the substrate surfaces 10a and 10b were monitored by pyrometers 13a and 13b from the substrate observation windows 12a and 12b, and maintained at a predetermined temperature. In this state, a mixed gas of argon, hydrogen, and methane is introduced from the gas introduction ports 6a, 6b, and the microwaves generated from the microwave power supplies 7a, 7b are introduced into the vacuum chamber through the microwave waveguides 8a, 8b. The microwave resonance conditions were adjusted by the microwave resonance plates 9a and 9b to generate microwave plasma on both sides of the substrate support 3. As a result, the growth of the diamond film on both surfaces of the substrate 10 started. Diamond films were grown to a thickness of 50 μm on each side.

FIG. 3 shows the structure of a hot filament CVD apparatus according to a second embodiment of the present invention. FIG. 4 shows the substrate holder of the device. Elements having basically the same functions as those of the embodiment shown in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

The vacuum chamber 21 is composed of a right chamber 21a and a left chamber 21b having a structure symmetrical with respect to the substrate holder 3 disposed at the center.
Inside each of the left and right chamber portions 21a and 21b, hot filaments 24a and 24b are arranged near the substrate holder 3, and each hot filament 24a and 24b is connected to a power supply 25.
a. 25b.

The substrate holder 3 is, as shown in FIG. 4, a pipe frame 1 which is configured as a cooling water pipe as a whole.
4 and one circular frame-shaped substrate mounting plate 15 fixed so as to be surrounded by the pipe frame 14. One circular substrate 10 can be fixed to the substrate mounting plate 15.

Using this embodiment, a film formation test was performed as follows. After the substrate 10 was scratched on both surfaces under the same conditions, the substrate 10 was attached to the substrate holder 3, and 1 SLM of cooling water was introduced from the cooling water inlet 4 of the substrate holder 3 and drained from the cooling water outlet 5. The substrate 10 has a thickness of 0.5 mm and a diameter of 25 m.
m of SiC substrate was used. In the scratching process, the particle size is 14μ.
The two-sided lap polishing was performed using a diamond abrasive grain of less than m. By operating the vacuum pumps 2a and 2b, the vacuum chamber 21 is operated.
The inside was evacuated to a vacuum of 0.001 torr, and this vacuum was maintained while the vacuum pumps 2a and 2b were operating. Power was applied to the substrate heating high-frequency coil 11, and the temperatures of the substrate surfaces 10a and 10b were monitored from the substrate observation windows 12a and 12b by pyrometers 13a and 13b, and maintained at a predetermined temperature. In this state, the gas inlets 6a, 6b
, A mixed gas of argon, hydrogen, and methane is introduced.
Electric power was supplied to 4a and 24b to heat the filament surface. As a result, the growth of the diamond film on both surfaces of the substrate 10 started. A diamond film with a thickness of 100 on each side
grown by μm.

FIG. 5 is a graph showing R according to the third embodiment of the present invention.
1 shows a structure of an F plasma CVD apparatus. Note that elements having basically the same functions as those of the above-described embodiment are denoted by the same reference numerals, and redundant description will be omitted.

The vacuum chamber 41 comprises a right chamber part 41a and a left chamber part 41b having a structure symmetrical with respect to the substrate holder 3 disposed at the center.
Plasma gas introduction pipes 29a and 29b pass through the inside of each of the left and right chamber portions 41a and 41b, and outlets (nozzles) 29a of the plasma gas introduction pipes 29a and 29b.
Reference numerals a and 29ba face the right and left surfaces 10a and 10b of the substrate 10 fixed to the substrate holder 3, respectively. RF coils 27a and 27b for generating high-frequency energy for converting the plasma gas into plasma surround the nozzle portions of the plasma gas introduction pipes 29a and 29b, respectively.
8a and 28b are connected. Also, the inside of each of the left and right chamber portions 41a, 41b is provided with a raw material gas introduction pipe 26.
a, 26b, and each raw material gas introduction pipe 26a, 2b
The outlet of 6b is directed to the plasma jet ejected from the nozzles 29aa, 29ba of each of the plasma gas introduction pipes 29a, 29b. The substrate holder 3 has basically the same configuration as that shown in FIG. 4, but one square substrate 10 can be fixed thereto.

Using this embodiment, a film forming test was performed as follows. After the substrate 10 was scratched on both surfaces under the same conditions, the substrate 10 was attached to the substrate holder 3, and 1 SLM of cooling water was introduced from the cooling water inlet 4 of the substrate holder 3 and drained from the cooling water outlet 5. As the substrate 10, a Mo substrate having a thickness of 0.4 mm and a plane size of 50 × 50 mm was used. In the scratching process,
Both sides were lapped and polished using diamond abrasive grains having a particle size of less than 3 μm. The vacuum pumps 2a and 2b were operated to evacuate the inside of the vacuum chamber 21 to a vacuum degree of 0.001 torr, and this vacuum degree was maintained while the vacuum pumps 2a and 2b were operated. Also, applying power to the substrate heating high-frequency coil 11,
Pyrometer 13a from substrate observation windows 12a, 12b,
13b monitors the temperatures of the substrate surfaces 10a and 10b,
This was maintained at a predetermined temperature. In this state, a mixed plasma gas of argon and hydrogen is introduced from the plasma gas introduction pipes 29a and 29b.
Electric power was supplied to the RF coils 27a and 27b from 8b to convert the plasma gas into plasma, which was ejected toward the substrate 10.
In addition, ethyl alcohol vapor, which is a diamond raw material, was introduced from the raw gas introduction pipes 26a, 26b. As a result, the growth of the diamond film on both surfaces of the substrate 10 started. A diamond film was grown to a thickness of 30 μm on each side.

FIG. 6 shows D according to the fourth embodiment of the present invention.
1 shows the structure of a C arc plasma CVD apparatus. Note that elements having basically the same functions as those of the above-described embodiment are denoted by the same reference numerals, and redundant description will be omitted.

The vacuum chamber 51 is composed of a right chamber 51a and a left chamber 51b having a structure symmetrical with respect to the substrate holder 3 disposed at the center.
Inside each of the left and right chambers 51a and 51b, there is provided a DC plasma torch 3 having electrodes and nozzles surrounding the electrodes.
0a and 30b are arranged. Each DC plasma torch 30a, 30b has a plasma gas introduction pipe 29a, 29b for introducing a plasma gas between its electrode and the nozzle.
Are connected, and DC power supplies 31a and 31b for applying a DC arc voltage between the electrode and the nozzle are connected. The plasma jet port at the tip of each DC plasma torch 30a, 30b is connected to the substrate 10 fixed to the substrate holder 3.
Are directed to the right and left surfaces 10a, 10b. Further, the source gas introduction pipes 26a and 26b
The outlet is directed to the plasma jet ejected from the plasma torches 30a, 30b. The substrate holder 3 has basically the same configuration as that shown in FIG. 4, but one square substrate 10 can be fixed thereto.

Using this embodiment, a film formation test was performed as follows. After the substrate 10 was scratched on both surfaces under the same conditions, the substrate 10 was attached to the substrate holder 3, and 1 SLM of cooling water was introduced from the cooling water inlet 4 of the substrate holder 3 and drained from the cooling water outlet 5. The substrate 10 has a thickness of 0.4 mm and a plane size of 2
An AlN substrate of 0 mm × 20 mm was used. In the scratching treatment, double-sided lap polishing was performed using SiC abrasive # 2500. By operating the vacuum pumps 2a and 2b, the vacuum chamber 21 is operated.
The inside was evacuated to a vacuum of 0.001 torr, and this vacuum was maintained while the vacuum pumps 2a and 2b were operating. Power was applied to the substrate heating high-frequency coil 11, and the temperatures of the substrate surfaces 10a and 10b were monitored from the substrate observation windows 12a and 12b by pyrometers 13a and 13b, and maintained at a predetermined temperature. In this state, the plasma gas introduction pipe 2
A mixed plasma gas of argon and hydrogen is introduced from 9a and 29b, and an arc discharge is generated in the plasma torches 30a and 30b from the DC power supplies 31a and 31b in the introduced state, and the plasma gas is turned into plasma and ejected toward the substrate 10. Was. In addition, ethyl alcohol vapor, which is a diamond raw material, was introduced from the raw gas introduction pipes 26a, 26b. As a result, the growth of the diamond film on both surfaces of the substrate 10 started. Diamond film thickness of 200 on each side
grown by μm.

FIG. 7 shows a film formation test using the above embodiment.
As shown in (1), a diamond film 52 of the same thickness and the same quality was simultaneously formed on both surfaces of the substrate 10. Warpage of double-sided diamond film substrate made by film formation test (Δ in the figure)
Was measured, the warp Δ was less than 5 μm in any of the embodiments. As a comparative test, a substrate in which a diamond film having the same thickness was formed on one surface under the same conditions was prepared and its warpage was measured. The warpage was 50 μm or more. Therefore, according to the above embodiment, the amount of warpage was successfully reduced by about one digit as compared with the related art. Also,
When the diamond film surfaces on both surfaces of the double-sided diamond film substrate prepared in the above embodiment were simultaneously polished using both ready-made polishing machines, the surface roughness Ra5n was maintained without breaking the substrate.
m was obtained.

FIG. 8 shows a schematic configuration of a DC plasma CVD apparatus according to a fifth embodiment of the present invention. Note that elements having basically the same functions as those of the above-described embodiment are denoted by the same reference numerals, and redundant description will be omitted.

In the vacuum chamber 71, a plurality of substrate holders 3a and 3b are arranged in parallel at regular intervals. A plurality of DC plasma torches 30a, 30b, 30c are arranged at regular intervals so as to sandwich the substrate holders 3a, 3b, and the plasma jets 72a, 72b, 72c are substantially arranged in spaces on both sides of each of the substrate holders 3a, 3b. Gushing.
A raw material gas is supplied to the plasma jets 72a, 72b, 72c from a raw gas introduction pipe (not shown). The plasma torches 30a, 30b are formed so that film formation is performed under the same conditions on both sides of all the substrates 10 fixed to the substrate holders 3a, 3b.
The operating conditions of 30b and 30c, the amount of source gas introduced, and the like are adjusted. Also in this embodiment, a diamond film having the same thickness is simultaneously formed on both surfaces of the substrate 10.

FIGS. 9 and 10 show an embodiment of a product using the double-sided diamond film substrate of the present invention.

The product shown in FIG. 9 is a semiconductor IC, in which a heat spreader 63 using a substrate 65 having a diamond film 64 on both surfaces is embedded in a casing 62 thereof. The IC chip 6 is placed on the heat spreader 63.
1 is mounted. The electric terminals of the IC chip 61 are connected to the lead frame 66 by bonding wires 67. By using a heat spreader having a diamond film on both sides, it can be expected that a higher heat release ability can be exhibited than a conventional heat spreader having a diamond film on only one side.

As a modification, IC chips can be mounted on both sides of a heat spreader of a double-sided diamond film.

The product shown in FIG. 10 is a SAW filter, in which an input-side transmitting / receiving electrode 82, an output-side transmitting / receiving electrode 83, and a shield electrode 84 of a diamond film etched in a predetermined pattern are formed on the front surface of a substrate 81. Etc. are formed. Although not shown in the figure, the diamond film on the back surface of the substrate 81 is also etched into a predetermined pattern to form another SAW circuit (or one SAW circuit together with the diamond film pattern on the front surface). . When a SAW device is configured using the diamond films on both surfaces of the substrate in this manner, it is possible to configure a SAW circuit having a smaller size than a conventional SAW circuit. In order to make the stress uniform or nearly equal on both surfaces of the substrate, it is desirable that the diamond film patterns on both surfaces of the substrate are the same or similar. Of course,
The SAW circuit may be configured using only one side of the diamond film, and the other side of the diamond film may be left unprocessed and not used.

The double-sided diamond film substrate can be used for all of the same uses as the conventional single-sided diamond substrate such as a pressure-resistant disk, a disk protective film, an X-ray window, etc.
In that case, advantages such as higher mechanical strength than a single-sided diamond film substrate, use of a double-sided diamond film, or good thermal conductivity can be utilized.

The embodiment of the present invention has been described above.
These embodiments are merely examples for describing the present invention, and are not intended to limit the present invention only to these embodiments. Therefore, the present invention can be implemented in various forms other than the above-described embodiment. The present invention
The present invention can be applied not only to a diamond film but also to other materials.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the structure of a microwave plasma CVD apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a substrate holder used in the apparatus of FIG.

FIG. 3 is a sectional view showing a structure of a hot filament CVD apparatus according to a second embodiment of the present invention.

FIG. 4 is a perspective view showing a substrate holder used in the apparatus of FIG.

FIG. 5 is a sectional view showing the structure of an RF plasma CVD apparatus according to a third embodiment of the present invention.

FIG. 6 is a sectional view showing the structure of a DC plasma CVD apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a cross-sectional view of a substrate having a diamond film formed on both sides.

FIG. 8 shows a schematic configuration of a DC plasma CVD apparatus according to a fifth embodiment of the present invention.

FIG. 9 is a sectional view showing an embodiment of a semiconductor IC using a double-sided diamond film substrate as a heat spreader.

FIG. 10 is a perspective view showing an embodiment of a SAW filter using a double-sided diamond film substrate.

[Explanation of symbols]

 1, 21, 41, 51, 71 Vacuum chamber 1a, 21a, 41a, 51a Right chamber 1b, 21b, 41b, 51b Left chamber 3 Substrate holder 10 Substrate 52 Diamond film

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H03H 3/08 H03H 3/08 H05H 1/46 H05H 1/46 A F term (Reference) 4G077 AA03 BA03 DB07 DB11 DB17 DB18 DB19 ED04 ED06 EE01 EG03 FG01 FG05 HA04 HA06 HA14 HA20 TA04 TA12 TE02 TE03 TE05 TF04 TG01 TK01 4K030 AA10 AA16 AA17 BA28 BB11 CA02 CA04 CA05 DA02 DA08 FA01 FA04 GA02 JA01 KA23 KA26 KA30 KA26 KA30 KA26

Claims (18)

[Claims] 1. A substrate holder supporting a substrate, a first film forming unit disposed on one side of the substrate supported by the substrate holder and acting on one side of the substrate, A second film formation unit disposed on the other surface side of the substrate supported by the substrate holder and acting on the other surface of the substrate, wherein the first and second film formation units are provided. A film forming apparatus for forming a film of a predetermined substance on both sides of the substrate by the method. 2. The film forming apparatus according to claim 1, wherein the first and second film forming units are configured to form films on both surfaces of the substrate substantially simultaneously and under the same conditions. 3. The film forming unit according to claim 1, wherein the first and second film forming units have a structure symmetric with respect to the substrate holder.
A film forming apparatus as described in the above. 4. The film forming apparatus according to claim 1, wherein the substrate holder has a substrate cooling device or a substrate heating device for adjusting a temperature of the substrate. 5. The film forming apparatus according to claim 1, wherein each of said first and second film forming units forms a film of said predetermined material by a plasma CVD method. 6. The film forming apparatus according to claim 1, wherein the predetermined substance is diamond. 7. A substrate holder for supporting one or more substrates, and a plurality of film forming units arranged so as to sandwich each of the substrates supported by the substrate holder, wherein the plurality of film forming units are A film forming apparatus for forming a film of a predetermined material on both sides of each substrate. 8. A diamond film forming apparatus, comprising: a substrate holder for supporting a substrate with both surfaces exposed, and a film forming mechanism for forming a diamond film on both surfaces of the substrate supported by the substrate holder. . 9. A substrate holder for supporting a substrate with both surfaces thereof exposed and adjusting the temperature of the substrate, and forming a film of a predetermined substance on both surfaces of the substrate supported by the substrate holder. A film forming apparatus provided with a mechanism. 10. A step of generating a radical of a raw material of a predetermined substance on one side of the substrate to form a first film of the predetermined substance on one side of the substrate; Generating a radical of a raw material of the predetermined substance on the side of the surface, and forming a second film of the predetermined substance on the other surface of the substrate. 11. The method according to claim 10, further comprising the step of polishing the surfaces of the first and second films. 12. A method for manufacturing a double-sided diamond film substrate, comprising: forming a first diamond film on one surface of a substrate; and forming a second diamond film on the other surface of the substrate. . 13. A first substance of a predetermined substance is provided on one side of the substrate.
Forming a second film of a predetermined substance on the other surface of the substrate substantially simultaneously and under the same conditions as the formation of the first film. Manufacturing method of surface film substrate. 14. A substrate having on both sides a film of a predetermined substance having substantially the same thickness. 15. The substrate according to claim 14, wherein said predetermined substance is diamond. 16. A semiconductor device comprising: a semiconductor circuit chip; and a heat spreader or a heat sink coupled to the semiconductor circuit chip and using a substrate having a diamond film on both surfaces. 17. A SAW device comprising: a substrate having a diamond film on both surfaces; and a SAW circuit formed by processing the diamond film on at least one surface of the substrate. 18. A product utilizing a diamond film using a substrate having a diamond film on both surfaces.