JPH1088355A - Plasma cvd system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma CVD system capable of controlling the distribution in the coating thickness of thin coating to be formed on a substrate so as to be made uniform. SOLUTION: This plasma CVD system is the one in which a gas introducing port 11 for introducing a gaseous starting material into a vacuum tank 2 provided with an exhaust system and an electrode for applying discharge voltage to the gaseous starting material are provided, a reaction tube 9 is set in such a manner that the opening part 9b is arranged proximately to the surface of a substrate 5 so as to be confronted therewith with prescribed intervals, and thin coating is formed by a plasma chemical vapor growth method. In this case, a gas dispersing board 12 in which plural empty holes are uniformly arranged is arranged between the electrode and the gas introducing port 11, the reaction tube 9 is supported by a supporting mechanism absorbing the expansion and shrinkage caused by the heating and cooling of the reaction tube 9, and a displacement measuring mechanism detecting the amt. of the displacement of the reaction tube caused by themal expansion is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma CVD apparatus for forming a thin film on a substrate surface by a plasma vapor deposition method.

[0002]

2. Description of the Related Art As a method of forming a thin film, a sputtering method, a plasma CVD method, or the like can be used. Among them, in the sputtering method, a sputtering gas such as Ar is ionized (plasmaized) using an electric field or a magnetic field, and is caused to collide with a target surface by being accelerated. Then, target atoms are repelled from the target to which the plasma particles collide, and the repelled atoms are deposited on the object to be deposited.
A sputtered film is formed. However, when a carbon film is formed by this sputtering method, the film forming speed is generally slow,
Poor productivity from an industrial point of view.

On the other hand, in the plasma CVD method, a raw material gas as a raw material of a thin film is caused to undergo a chemical reaction such as decomposition or synthesis by the energy of plasma generated by an electric field.
A reactant generated as a result of this chemical reaction is deposited on the object to be deposited, whereby a CVD film is formed. This plasma C
The VD method has a higher deposition rate than the sputtering method,
This is expected as a means for forming a carbon film.

[0004]

In the above-mentioned plasma CVD method, in order to form a thin film by making the film thickness distribution uniform, it is necessary to make the plasma density uniform on the film formation surface on the substrate. is important.

However, the conventional plasma CVD
In the apparatus, the raw material gas was poorly dispersed, and the plasma density became non-uniform inside the reaction tube, so that a uniform film thickness distribution could not be obtained. Further, in a conventional plasma CVD apparatus, the temperature inside the reaction tube may increase due to plasma heat or electrode heating, and the reaction tube may expand and deform.
Therefore, the gap between the substrate and the reaction tube becomes non-uniform, that is, the plasma density when the film is formed on the substrate becomes non-uniform in the film-forming surface width direction, and a uniform film thickness distribution is obtained. There was a problem that it could not be done.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above problems, and is a plasma CVD apparatus capable of controlling a film thickness distribution of a thin film formed on a substrate to be uniform. The purpose is to provide.

[0007]

Means for Solving the Problems Plasma C according to the present invention
The VD device includes a gas inlet for introducing a source gas and an electrode for applying a discharge voltage to the source gas in a vacuum chamber provided with an exhaust system, and an opening thereof faces the substrate surface at a predetermined interval. In a plasma CVD apparatus for forming a thin film by plasma enhanced chemical vapor deposition, a plurality of pores are uniformly formed between an electrode and a gas introduction port. Wherein the gas distribution plate disposed in the above is disposed.

According to this plasma CVD apparatus, since a gas dispersion plate in which a plurality of holes are uniformly arranged is arranged between the gas inlet and the electrode, the source gas is uniformly dispersed. By making the plasma density uniform,
The thickness distribution of the thin film can be made uniform.

Further, the plasma CVD apparatus according to the present invention is provided with a gas inlet for introducing a source gas and an electrode for applying a discharge voltage to the source gas in a vacuum chamber having an exhaust system. A plasma CVD apparatus for forming a thin film by plasma-enhanced chemical vapor deposition, wherein the reaction tube is disposed adjacent to the substrate surface at a predetermined interval so as to face the substrate surface. It is characterized by being supported by a support mechanism that absorbs expansion and contraction caused by heating and cooling.

According to this plasma CVD apparatus, since the support mechanism is provided, the expansion and contraction of the reaction tube is absorbed, and the reaction tube is not distorted unevenly. Therefore, in this plasma CVD apparatus, it is possible to prevent the reaction tube from being distorted and the gap between the substrate and the reaction tube from becoming non-uniform, and the film thickness distribution of the thin film can be made uniform.

Further, the plasma CVD apparatus according to the present invention is provided with a gas inlet for introducing a source gas and an electrode for applying a discharge voltage to the source gas in a vacuum chamber having an exhaust system. In a plasma CVD apparatus for forming a thin film by plasma enhanced chemical vapor deposition, a reaction tube is disposed in such a manner that the reaction tube is disposed close to the substrate surface at a predetermined interval so as to face the substrate surface. A displacement amount measuring mechanism for detecting the amount is provided.

According to this plasma CVD apparatus, since the displacement measuring mechanism is provided, even if the reaction tube is distorted, the displacement can be detected, and a countermeasure against the displacement can be taken immediately. It is possible to take.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a plasma CVD apparatus to which the present invention is applied, and a carbon film is formed as a protective film on a film in which a metal magnetic film is formed on a non-magnetic support by using the same, for example. A method for forming a thin film will be described in detail with reference to the drawings.

In the present embodiment, a plasma CVD apparatus for forming a film on a film-like substrate and a method for forming a carbon film will be described.
It is needless to say that the present invention is not limited to this, and the shape, material and the like can be arbitrarily changed without departing from the gist of the present invention.

First, the plasma CVD apparatus 1 will be described. As shown in FIG. 1, the plasma CVD apparatus 1 includes a feed roll 3 and a feed roll 3 in a vacuum chamber 2 evacuated by an exhaust system (not shown) to form a vacuum state.
A take-up roll 4 is provided, and a film 5 made of polyethylene terephthalate, polyimide, or the like is sequentially run from the feed roll 3 toward the take-up roll 4.

From these feed rolls 3 to take-up rolls 4
A cylindrical can 6 having a larger diameter than the rolls 3 and 4 is disposed in the middle of the film 5 running on the side.

Accordingly, the film 5 is sequentially fed from the feed roll 3, travels and travels along the peripheral surface of the cylindrical can 6, and is sequentially wound up by the take-up roll 4.

Further, between the feed roll 3 and the cylindrical can 6, and between the cylindrical can 6 and the winding roll 4.
Guide rolls 7 and 8 each having a smaller diameter than each of the rolls 3 and 4 are arranged between the rolls 3 and 4, and travel from the feed roll 3 to the cylindrical can 6 and from the cylindrical can 6 to the take-up roll 4. A predetermined tension is applied to the film 5 so that the film 5 runs smoothly.

As shown in FIGS. 1 and 2, a reaction tube 9 is disposed below the cylindrical can 6 so as to be opposed to the surface of the film 5 wound around the cylindrical can 6. You. The reaction tube 9 has a reaction tube body 9a for accommodating the electrode 10.
And an opening 9 b curved so as to be substantially parallel to the peripheral surface of the cylindrical can 6. The opening 9b
Is preferably 1.5 times or more in cross-sectional area ratio with the reaction tube body 9a.

A gas supply pipe 11 for supplying a raw material gas containing a hydrocarbon compound as a main component is connected to the inside of the reaction pipe 9, and a gas dispersion plate 12 is provided in front of the gas supply pipe 11. Can be Further, an electrode 10 having a plurality of holes and formed in a mesh shape is arranged in front of the gas dispersion plate 12 in the reaction tube 9. Then, the raw material gas introduced from the gas supply pipe 11 becomes a plasma state when passing through the electrode 10 to which a discharge voltage is applied by a DC power supply, and causes a predetermined reaction in the reaction tube 9. The decomposition product at this time is applied to the film 5 running on the peripheral surface of the cylindrical can 6.
And a carbon film is formed continuously.

As shown in FIG. 4, a plurality of gas introduction pipes 11 are connected to a reaction tube bottom plate 13 at predetermined intervals by a gas introduction joint 14 via a gas introduction flange 15 made of polycarbonate. . Gas dispersion plate 1
3 has a plurality of holes 12a formed uniformly and is arranged so as to be close to the reaction tube bottom plate 13, as shown in FIGS.

The gas dispersion plate 12 has a plurality of holes 12a.
Are uniformly formed, so that the source gas introduced from the gas introduction tube 11 can be uniformly dispersed in the reaction tube 9. Further, by providing a plurality of gas introduction pipes 11, the source gas is more easily dispersed. As described above, the plasma CVD apparatus 1 including the gas dispersion plate 12
In the method, the source gas is uniformly dispersed, the plasma density becomes uniform, and a thin film having a uniform film thickness distribution can be obtained.

Further, as shown in FIGS. 5 and 6, the reaction tube 9 is provided with first support shafts 18, 20 and second support shafts 19, 19 on both sides of the reaction tube body 9a. Standing up, a first support shaft 18, 20 and a second support shaft 19,
Numeral 19 is locked to a reaction tube table 21 arranged opposite to each side surface. The reaction tube holder 21 is fixed to a gap adjusting uniaxial slide stage 25 via a support plate 21a. In this manner, the reaction tube body 9a to which the reaction tube table 21 is attached can be slid in the direction of arrow B (shown in FIG. 5) by the gap adjusting uniaxial slide stage 25.

Meanwhile, one of the first support shafts 18 is urged in the axial direction by an elastic means (spring) 17 so that the first support shaft 18 can be inserted into and removed from the reaction tube table 21 via a ball bush. When the reaction tube body 9a expands, it absorbs the distortion in the direction of arrow B. Further, the second support shaft 19 is
In any case, the notch 2 provided on the reaction tube table 21
2, which is removably inserted and absorbs distortion in the direction of arrow B when the reaction tube body 9a expands. Note that, here, the first support shaft 20 has a structure in which no elastic means is interposed. However, this is because one side is a base point, and the left and right configurations may be interchanged.

Therefore, the first support shaft 18, the second support shaft 19, and the reaction tube 9 supported by the reaction tube
Even if is expanded by heating, the elastic means 17 provided on the first support shaft 18 absorbs the expansion in the horizontal direction, that is, the direction of arrow A (shown in FIG. 6) with respect to the film formation surface. . At the same time, the expansion of the reaction tube 9 in the direction perpendicular to the film formation surface, that is, in the direction of arrow B, is released by the cutout portion 22 provided in the reaction tube table 21. Similarly,
When the reaction tube 9 expanded by heating is cooled and contracted, the contraction of the reaction tube 9 is absorbed by the first support shaft 18 and the second support shaft 19.

Since the conventional reaction tube is directly fixed to the vacuum chamber by the support shaft, expansion is suppressed, uneven distortion occurs, and film formation becomes impossible. Has a support mechanism that absorbs expansion and contraction caused by heating and cooling, thereby preventing uneven distortion. Therefore, plasma CVD provided with this support mechanism
The apparatus 1 can maintain a uniform gap G between the film formation surface of the film 5 and the reaction tube opening 9b, so that a thin film having a uniform film thickness distribution can be obtained.

In addition, four corners of the reaction tube opening 9b are shown in FIG.
As shown in FIG. 9, the laser displacement sensor 23 (23a, 23a) measures the displacement of the reaction tube opening 9b during film formation.
b, 23c, 23d) are installed so as to face the cylindrical can 6, respectively. Then, the measurement block 24 (24
a, 24b, 24c, 24d) are fixed to a cylindrical can support plate (not shown) and the laser displacement sensor 23
Are disposed so as to be orthogonal to the optical axis of the laser light emitted from the laser beam. Therefore, the displacement amount of the reaction tube opening 9b, that is, the displacement amount of the gap G between the peripheral surface of the cylindrical can 6 and the reaction tube opening 9b is determined by the distance (reflected light amount) between the laser displacement sensor 23 and the measurement block 24. Measured. For example, the displacement of the reaction tube can be measured with a resolution of 2 μm.

As described above, in the plasma CVD apparatus 1 provided with the displacement amount measuring mechanism, even if the reaction tube 9
Even if distortion occurs, the amount of displacement can be detected,
Immediate measures can be taken against this.

Here, the pressure in the reaction tube 9 when the carbon film is formed using the plasma CVD apparatus 1 described above, the outer surface temperature of the reaction tube 9 and each laser displacement sensor (trade name: Z4M- 40, manufactured by OMRON Corporation) 23a, 23
FIG. 1 shows the results obtained when the displacement amounts of b, 23c and 23d were measured.
It is shown in FIG.

From the results shown in FIG. 11, although the pressure rises with the temperature rise, the displacement of the reaction tube 9 was ± 0.2 mm or less. This is one-tenth or less of the displacement of a conventional reaction tube without the above-mentioned support mechanism. That is, the gap G between the peripheral surface of the cylindrical can 6 and the reaction tube opening 9a was kept uniform. At this time, the film thickness distribution in the film forming surface width direction could be controlled to ± 10% or less with respect to the set film thickness.

As can be seen from these results, the plasma CVD apparatus 1 to which the present invention is applied is provided with the dispersion plate 12 behind the electrode 10, and the reaction tube 9 expands and contracts the reaction tube 9.
The raw material gas is uniformly dispersed in the reaction tube 9 because it is supported by the reaction tube mounting table 21 having a support mechanism for absorbing contraction and has a displacement measuring mechanism (displacement sensor 23, measuring block 24). Even if the reaction tube 9 expands due to heat, it is not distorted and the gap G between the base 5 and the reaction tube opening 9b is kept uniform, so that the film can be formed with a uniform plasma density. Therefore, in the plasma CVD apparatus 1, since a uniform plasma density is obtained, the thickness distribution of the carbon film can be controlled uniformly.

[0032]

As is clear from the above description, in the plasma CVD apparatus according to the present invention, a gas distribution plate in which a plurality of holes are uniformly arranged is arranged between an electrode and a gas inlet. Therefore, the source gas is uniformly dispersed and the plasma density is made uniform, so that the film thickness distribution of the thin film can be made uniform.

Further, in the plasma CVD apparatus according to the present invention, since the reaction tube is supported by a support mechanism for absorbing expansion and contraction due to heating and cooling of the reaction tube, the reaction tube is distorted and the substrate and the reaction tube are distorted. Can be prevented from becoming non-uniform, and the film thickness distribution of the thin film can be made uniform.

Further, the plasma CVD apparatus according to the present invention is provided with a displacement measuring mechanism for detecting a displacement of the reaction tube due to thermal expansion. Can be detected, and a countermeasure against this can be taken immediately.

As described above, the dispersion plate for uniformly dispersing the raw material gas, the support mechanism for absorbing the expansion and contraction of the reaction tube, and the displacement amount measuring mechanism for detecting the displacement amount of the reaction tube due to thermal expansion are provided. The plasma CVD apparatus can maintain a uniform gap between the substrate surface and the reaction tube opening, and can uniformly control the thickness distribution of the thin film.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a plasma CVD apparatus to which the present invention is applied.

FIG. 2 is a perspective view of a main part showing a configuration of a reaction tube of the plasma CVD apparatus.

FIG. 3 is a plan view of a dispersion plate of the plasma CVD apparatus.

FIG. 4 is a front view of a gas inlet and a dispersion plate of the plasma CVD apparatus.

FIG. 5 is a front view of a reaction tube and an expansion countermeasure mechanism of the plasma CVD apparatus.

6 is a cross-sectional view of the reaction tube and the expansion countermeasure mechanism in FIG. 5, taken along line XX.

FIG. 7 is a plan view showing a reaction tube, a laser displacement sensor, and a measurement block of the plasma CVD apparatus.

FIG. 8 is a front view showing a reaction tube, a laser displacement sensor, and a measurement block of the plasma CVD apparatus.

FIG. 9 is a perspective view showing a reaction tube, a laser displacement sensor, and a measurement block of the plasma CVD apparatus.

FIG. 10 is an enlarged perspective view of a reaction tube, a laser displacement sensor, and a measurement block of FIG. 9;

FIG. 11 is a diagram showing a relationship between a film forming time when forming a film using the same plasma CVD, a pressure and a temperature inside the reaction tube, and a displacement amount of the reaction tube.

[Explanation of symbols]

1 plasma CVD device, 2 vacuum chamber, 5 film,
6 cylindrical can, 9 reaction tube, 10 electrode, 11 gas supply tube, 12 gas dispersion plate, 17 spring, 18
1st support shaft, 19 2nd support shaft, 20 1st support shaft, 21 Reaction tube stand, 22 Notch, 23 Laser displacement sensor, 24 Measurement block

Claims (5)

[Claims] A vacuum chamber provided with an exhaust system is provided with a gas inlet for introducing a source gas and an electrode for applying a discharge voltage to the source gas, and an opening is formed on the surface of the base body at a predetermined interval. In a plasma CVD apparatus for forming a thin film by plasma enhanced chemical vapor deposition, a plurality of holes are provided between an electrode and a gas inlet. A plasma CVD apparatus wherein gas dispersion plates are uniformly arranged. 2. A vacuum chamber provided with an exhaust system, comprising a gas inlet for introducing a source gas, and an electrode for applying a discharge voltage to the source gas, and an opening formed on the surface of the substrate at a predetermined interval. In a plasma CVD apparatus for forming a thin film by plasma-enhanced chemical vapor deposition, a reaction tube is disposed so as to be opposed to and close to each other, wherein the reaction tube expands and contracts due to heating and cooling of the reaction tube. A plasma CVD apparatus supported by an absorbing support mechanism. 3. A first support shaft and a second support shaft are erected on both side surfaces of the reaction tube, respectively, and the support shafts are engaged with a reaction tube table which is arranged to face each side surface. At least one of the first support shafts is urged in the axial direction by elastic means to be freely inserted into and removed from the reaction tube table. 3. The plasma CVD apparatus according to claim 2, wherein the plasma CVD apparatus is removably inserted into a notch provided in the reaction tube table, and rotation about the first support shaft is restricted. 4. A vacuum chamber provided with an exhaust system, comprising a gas inlet for introducing a source gas, and an electrode for applying a discharge voltage to the source gas, and an opening formed on the surface of the base body at a predetermined interval. In a plasma CVD apparatus for forming a thin film by plasma enhanced chemical vapor deposition, a displacement measuring mechanism for detecting a displacement of the reaction tube due to thermal expansion is provided. A plasma CVD apparatus, which is provided. 5. A displacement measuring mechanism is provided opposite to a laser displacement meter provided at an opening of a reaction tube and fixed to a vacuum chamber so as to be orthogonal to an optical axis of laser light of the laser displacement meter. 5. A measuring block comprising: a measuring block;
The plasma CVD apparatus as described in the above.