JP2011184709A - Cvd device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a CVD device capable of uniformly forming the entire surface of a film formed on a substrate surface. <P>SOLUTION: In the thermal CVD device for forming a carbon nano tube having a heating chamber 13 for forming the carbon nano tube on the surface of a substrate K by a thermal chemical vapor deposition method, a guide plate 23 holding the substrate K moved in a prescribed direction in the heating chamber 13 and having a prescribed width so as to give the side surface view thereof to an arc shape is provided and a discharge outlet 5 of a raw material gas G is disposed along the width direction of the substrate K in a center position of the arc of the substrate K held by the guide plate 23. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a CVD apparatus.

  A chemical vapor deposition apparatus (hereinafter referred to as a CVD apparatus), which is one of vapor deposition apparatuses, places a substrate in a reaction vessel filled with an inert gas or in a vacuum (depressurized state), and feeds a raw material gas into the reaction vessel. Thus, a film is grown on the surface of the substrate via a catalyst. Examples of the CVD apparatus include a thermal CVD apparatus that uses heat, a plasma CVD apparatus that uses plasma, and a photo CVD apparatus that uses light energy.

  2. Description of the Related Art Conventionally, as a vapor deposition apparatus, an apparatus in which an organic material heated by a crucible and evaporated is attached to a substrate disposed in a vacuum chamber (reaction vessel) is known (see, for example, Patent Document 1).

JP 2004-134250 A

  By the way, in the said vapor deposition apparatus, although the board | substrate is arrange | positioned planarly, the crucible is arrange | positioned so that the opening part may oppose the center of the substrate surface. For this reason, there is a difference in the distance from the opening of the crucible near the center and the outer periphery of the substrate surface, and there is also a difference in the concentration of the organic material in contact therewith. In particular, when the above vapor deposition apparatus is used for the chemical vapor deposition method (CVD method), if there is a difference in the concentration of the source gas in contact with the substrate surface at the start of the CVD, a difference in the growth of the film occurs, and the more uniform. A CVD apparatus capable of producing a film has been desired.

  Therefore, an object of the present invention is to provide a CVD apparatus capable of making the film formed on the substrate surface more uniform over the entire surface.

In order to solve the above problems, a CVD apparatus according to claim 1 of the present invention is a CVD apparatus having a heating chamber for depositing a deposition material on the surface of a substrate by a thermal chemical vapor deposition method,
A substrate holding means capable of holding a substrate having a predetermined width in the heating chamber so as to have an arc shape when viewed from the side is provided, and a vapor deposition material discharge port is provided at the center of the arc of the substrate held by the substrate holding means. It is arranged along the width direction of the substrate.

The CVD apparatus according to claim 2 is a CVD apparatus having a heating chamber for depositing a deposition material on the surface of a substrate by a thermal chemical vapor deposition method,
A substrate holding means capable of holding a substrate having a predetermined width that is moved in the heating chamber in a predetermined direction so as to have an arc shape when viewed from the side, and is deposited at a center position of the arc of the substrate held by the substrate holding means. Material discharge ports are arranged along the width direction of the substrate.

  Furthermore, a CVD apparatus according to a third aspect is the CVD apparatus according to the first or second aspect, wherein a heating member is disposed along the outer periphery of the guiding rotating body.

  According to the CVD apparatus, the surface on which the vapor deposition film of the substrate is generated has an arc shape, and the vapor deposition material discharge port is disposed at the center position of the arc. Also, the distance from the discharge port is equal, the concentration of the vapor deposition material on the substrate surface is uniform, and the vapor deposition film formed on the substrate surface can be made more uniform over the entire surface.

It is sectional drawing which shows schematic structure of the CVD apparatus concerning Example 1 of this invention. It is principal part sectional drawing which shows schematic structure of the CVD apparatus. It is AA sectional drawing of FIG. 2 which abbreviate | omitted the heating apparatus. It is AA sectional drawing of FIG. 2 which showed only the heating apparatus in the heating chamber.

Hereinafter, a CVD apparatus according to an embodiment of the present invention will be described based on specific examples.
In Example 1, a CVD apparatus using a thermal CVD apparatus for forming carbon nanotubes will be described.

  In this example, as a substrate for forming carbon nanotubes, a stainless steel sheet, that is, a stainless steel sheet (an example of a sheet material, for example, a foil material having a thickness of about 20 to 300 μm is used, It can also be referred to as a stainless steel foil.In the case of a plate material, a material having a thickness of about 300 μm to several mm is used. Long ones, that is, strips are used. Therefore, this stainless steel plate is wound around a roll, and when forming carbon nanotubes, the carbon nanotubes are continuously formed by being pulled out from this roll, and the stainless steel plate on which the carbon nanotubes are formed It is intended to be wound on a roll. That is, a stainless steel plate is pulled out from one unwinding roll, carbon nanotubes are formed (generated) on the surface of the pulled stainless steel plate, and then the stainless steel plate on which the carbon nanotubes are formed is wound on the other winding roll. Has been.

Hereinafter, a thermal CVD apparatus for forming carbon nanotubes on the surface of the above-described strip-shaped stainless steel plate (hereinafter, mainly referred to as a substrate) will be described.
As shown in FIG. 1, the thermal CVD apparatus includes a heating furnace 1 in which an elongated processing space for forming carbon nanotubes is provided in a furnace body 2. The processing space provided in is partitioned (divided) into a plurality of, for example, five rooms by partition walls 3 arranged at predetermined intervals.

  That is, in the furnace body 2, a stainless steel plate, that is, a substrate supply chamber 11 in which an unwinding roll 16 on which the substrate K is wound is disposed, and the substrate K drawn from the unwinding roll 16 is guided to the surface thereof. A pretreatment chamber 12 for performing pretreatment, a heating chamber (which can also be called a reaction chamber) 13 for guiding the substrate K pretreated in the pretreatment chamber 12 to form carbon nanotubes on the surface thereof, A post-processing chamber 14 for guiding the substrate K on which the carbon nanotubes are formed in the heating chamber 13 and performing post-processing, and a winding roll 17 for winding the substrate K that has been post-processed in the post-processing chamber 14 are provided. A substrate recovery chamber (also referred to as a product recovery chamber) 15 is provided. The rotation axes of the rolls 16 and 17 are horizontal, so that the substrate K drawn (guided) into the heating chamber 13 moves in a horizontal plane and has carbon nanotubes on the surface of the substrate K. To be formed. In addition, although not shown, outside the substrate supply chamber 11 and the substrate collection chamber 15, there are servo motors that drive the rolls 16 and 17 in order to pull out and take up the substrate K with the rolls 16 and 17, respectively. The servo motors and the rolls 16 and 17 are connected to each other by an airtight rotating shaft that penetrates the side walls of the chambers 11 and 15, respectively. In the following, the direction between the rolls 16 and 17, that is, the direction in which the substrate K moves is referred to as the front-rear direction, and the direction orthogonal to the front-rear direction on the horizontal plane is referred to as the left-right direction.

  In the pretreatment chamber 12, the surface of the substrate K, particularly the surface that forms the carbon nanotubes (the carbon nanotube generation surface, which will be described later, here is the lower surface) is washed, the passive film is applied, and the carbon nanotubes are generated. The catalyst fine particles, specifically, iron fine particles (metal fine particles) are applied. For cleaning, alkali cleaning or UV ozone cleaning is used. In addition, as a method for applying the passive film, a roll coater or LPD is used. As a method for applying the catalyst fine particles, sputtering, vacuum deposition, roll coater or the like is used.

In the post-processing chamber 14, the cooling of the substrate K and the inspection of the carbon nanotubes formed on the surface, that is, the lower surface of the substrate K are performed.
In the substrate recovery chamber 15, a protective film is attached to the upper surface (back surface) of the substrate K, and the substrate K, which is a stainless steel plate to which the protective film is attached, is taken up by the take-up roll 17. The reason why the protective film is attached to the upper surface of the substrate K is to protect the carbon nanotubes formed on the substrate K wound around the outer side when the substrate K is wound up.

  As described above, five chambers are formed in the furnace body 2 by the partition walls 3. Naturally, each partition wall 3 has a communication opening (also referred to as a slit) through which the substrate K can pass. 3a is formed.

  By the way, in the heating chamber 13, carbon nanotubes are formed (generated) by the thermal CVD method, but the inside is maintained at a predetermined vacuum level (negative pressure state), and the carbon nanotube generating gas, that is, the raw material Gas G is supplied, and it is considered that this raw material gas G does not leak into the adjacent room. For example, in the heating chamber 13, the raw material gas G is supplied from below together with an inert gas N such as helium gas and is discharged (pulled out) from above. In addition to the heating chamber 13, that is, the substrate supply chamber 11, the pretreatment chamber 12, the posttreatment chamber 14, and the product recovery chamber 15, an inert gas N such as helium gas is supplied from below and from above. Once exhausted (withdrawn), the air is prevented from entering.

Here, the heating chamber 13 will be described in detail.
That is, as shown in FIGS. 2 and 3, gas introduction for supplying a source gas G containing carbon (for example, acetylene gas is used) G to the center position in the left-right direction of the bottom wall portion 2 a of the heating chamber 13. The nozzle 9 is inserted so as to penetrate the bottom wall portion 2a from below, and the opening at the upper end of the gas introduction nozzle 9, that is, the discharge port 5, has a rectangular shape whose longitudinal direction is the left-right direction. In addition, a plurality of gas discharge ports (for example, discharge pipes) 6 for discharging gas are formed in the upper portion of the heating chamber 13 at predetermined intervals in the front-rear direction. A heat insulating material 4 having a predetermined thickness is attached to the inner wall surface that forms the heating chamber 13. Further, a gas collecting chamber 8 is formed between the upper wall portion 2 b and the heat insulating material 4 to guide the gas from each gas discharge port 6 and discharge it from one gas discharge port 7. The gas outlet 7 is provided on the upper wall 2b of the furnace body 2. Accordingly, the upper wall portion 2b, or the upper wall portion 2b and the upper heat insulating material 4 can be referred to as the upper portion of the heating chamber 13, and the bottom wall portion 2a or the bottom wall portion 2a and the lower heat insulating material 4 are heated. It can be said that the lower part of the chamber 13. A heating device 21 having a plurality of cylindrical (or rod-shaped) heating elements (heating members) 22 for heating the inside of the heating chamber 13 is provided above the substrate K as shown in FIG. (The illustration of the heating device 21 is omitted in FIG. 3). Details of the heating device 21 will be described later.

Further, although not shown, the heating chamber 13 is connected to an exhaust device (also a vacuum device) for exhausting the air in the heating chamber 13 to bring it under a predetermined reduced pressure.
In addition, the heating chamber 13 has two disk-like shapes each having a rotation shaft 24 parallel to the left-right direction at the center of the rotation surface 23a and holding both side edges of the substrate K in the left-right direction from the lower surface to the outer peripheral surface 23b. A guide plate (which is an example of a substrate holding member) 23 and a cylindrical pressing roller 25 disposed in parallel with the left-right direction at the front and rear positions of both guide plates 23 are provided. The rotating shaft 24 and the pressing roller 25 of the guide plate 23 are rotatably supported by brackets 26 (illustrated only in FIG. 3) provided inside the side walls. Further, in order to make the substrate K into an arc shape along the outer peripheral surfaces 23b of the both guide plates 23, the substrate K is arranged from the lower surface (inner periphery) side before and after the guide plates 23 from the guide plate 23 and the upper surface (outer periphery). ) Side is held by a pressing roller 25. Specifically, as shown in FIGS. 1 and 2, the heights of the upper end of the communication opening 3a of the partition wall 3 and the lower end of the pressing roller 25 are made equal, that is, from the communication opening 3a. The pressing roller 25 is arranged so that the substrate K is horizontal in the portion up to the pressing roller 25.

  On the other hand, the discharge port 5 of the gas introduction nozzle 9 is located at the center of the arc of the substrate K. That is, the guide plate 23 and the pressing roller 25 are arranged so that the center of the arc shape of the substrate K curved by the guide plate 23 and the pressing roller 25 coincides with the position of the discharge port 5. Further, as shown in FIG. 3, these two guide plates 23 are arranged such that the gas introduction nozzle 9 is positioned between the left and right positions of the gas introduction nozzle 9, that is, between the two guide plates 23. The source gas G from the discharge port 5 of the nozzle 9 reaches the arc-shaped portion of the substrate K without being blocked.

By the way, in order to eliminate the influence of the organic gas, the constituent material other than the substrate K in the heating chamber 13, for example, the heat insulating material 4, is made of an inorganic material such as silicon dioxide (SiO ₂ ) or aluminum dioxide (Al ₂ O ₃ ). Has been.

Here, the process in the pretreatment chamber 12 will be described.
In the pretreatment chamber 12, after the substrate K is washed, a passive film such as silica or alumina is applied, and further, for example, catalyst fine particles of metal such as iron (Fe) are applied on the upper surface of the passive film. . Of course, although not shown, in the pretreatment chamber 12, there are provided cleaning means for the substrate K, means for applying a passive film, and means for applying catalyst fine particles of metal such as iron (Fe).

  By the way, as the substrate K, a thin stainless steel plate (also a stainless steel foil) that has been rolled to a thickness of 20 to 300 μm and wound in a coil shape is used. Since there is a tensile residual stress in the winding direction, the substrate K warps due to the release of the residual stress during atomization of the catalyst and thermal CVD. In order to prevent such warpage, a mechanism for applying tension in the coil winding direction, specifically, tension is generated between the unwinding roll and the winding roll (for example, rotation of both rolls). The tension is generated by changing the speed, specifically, the one motor may be pulled and the other motor may be used to exhibit the brake function.) The substrate K may be pulled. Further, a weight may be provided on the winding roll side and pulled.

Next, the heating device 21 will be described with reference to FIGS. 2 and 4 (the configuration other than the heating device 21 in the heating chamber 13 is omitted in FIG. 4).
This heating device 21 is arranged on the upper surface (outer periphery) side of the arc-shaped substrate K, and a columnar (or rod-shaped) heating element 22 is parallel (parallel) to the left-right direction and in the front-rear direction. A plurality are arranged at predetermined intervals. Further, the curved surface including these heating elements 22 is configured to have an arc shape concentric with the substrate K in a side view. Note that a non-metallic resistance heating element is used as the heating element 22, and specifically, silicon carbide, molybdenum silicide, lanthanum chromite, zirconia, graphite, or the like is used. In particular, silicon carbide and molybdenum silicide are used in a nitrogen gas or hydrogen gas atmosphere, lanthanum chromite is used only in the air, and graphite is used in an inert gas atmosphere (reducing atmosphere).

  Further, the heating element 22 is a cylindrical one and is formed in a circular arc shape that is concentric with the substrate K at predetermined intervals, that is, the heating element 22 has the same distance to the substrate K. Therefore, it is desired to make the heating to the substrate K uniform by the heating elements 22, that is, to equalize the temperature and maximize the soaking area. That is, the arrangement of the heating element 22 and the distance from the center of the heating element 22 to the substrate K are required to be appropriately arranged (that is, designed).

By the way, when the thermal CVD method is performed in the heating furnace 1, the inside of the heating chamber 13 is depressurized to a predetermined pressure.
This reduced pressure value is maintained in the range of several Pa to 1000 Pa. For example, it is maintained at several tens Pa to several hundred Pa. The lower limit of the reduced pressure range of several Pa is a limit value for maintaining the carbon nanotube formation rate (deposition rate), and the upper limit of 1000 Pa is a limit value in terms of soot and tar suppression. is there. In addition, as a constituent member in the forming container 1, a non-metallic material is used so that generation of soot, tar and the like is not promoted.

  By the way, the processing chambers other than the heating chamber 13, that is, the substrate supply chamber 11, the preprocessing chamber 12, the postprocessing chamber 14, and the product recovery chamber 15 have not been described in detail. , 15 are also in a reduced pressure state, and in order to prevent gas such as air that adversely affects the formation of carbon nanotubes from flowing into the heating chamber 13, as shown in FIG. Is provided with a gas supply port 5 ′ for supplying an inert gas such as helium gas, and a gas discharge port 6 ′ is provided in the upper wall portion 2 b.

FIG. 1 shows a schematic configuration of a thermal CVD apparatus, and the side wall portion on the near side and the heat insulating material 4 are omitted so that the inside thereof can be understood.
Next, a method for forming carbon nanotubes using the thermal CVD apparatus will be described.

  First, the substrate K is pulled out from the unwinding roll 16, and the communication openings 3 a of the partition walls 3 in the pretreatment chamber 12, the heating chamber 13, and the posttreatment chamber 14 are inserted, and the leading ends thereof are wound around the winding roll 17. Make it. At this time, tension is applied to the substrate K so that a straight horizontal surface is formed from the communication opening 3 a to the guide plate 23.

  Then, after the substrate K is cleaned in the pretreatment chamber 12, a passive film is applied over the entire lower surface, and iron fine particles are applied (attached) to the surface of the passive film. In addition, about the application | coating range of this catalyst fine particle, what is necessary is just the formation surface (generation surface) of a carbon nanotube at least.

  After this pretreatment, the substrate K is taken up by the take-up roll 17 by a predetermined length, that is, by a length for forming the carbon nanotube. Therefore, the portion where the pretreatment is performed in the pretreatment chamber 12 is sequentially moved into the heating chamber 13. Here, the portion where the carbon nanotube is formed is curved into an arc shape by the guide plate 23 and the pressing roller 25, and the substrate K is held. Since the guide plate 23 and the pressing roller 25 are rotatable, the substrate K can be moved smoothly.

In the heating chamber 13, the exhaust device (not shown) is maintained under a predetermined reduced pressure, for example, within a range of several Pa to 1000 Pa, specifically, several tens Pa to several hundred Pa as described above. .
Then, the temperature of the substrate K is heated to a predetermined temperature, for example, 700 to 800 ° C. by the heating device 21, that is, the heating element 22, and the outer wall temperature of the heating chamber 13 is 80 ° C. or lower (preferably 50 ° C. or lower). To be.

When the above temperature is reached, acetylene gas (C ₂ H ₂ ) is supplied as a source gas from the discharge port 5 to cause a predetermined reaction, thereby generating (growing) carbon nanotubes on the lower surface of the substrate K.

  Then, when a predetermined time passes and a carbon nanotube having a predetermined height is obtained, the substrate K is similarly moved by a predetermined length, and the substrate K on which the carbon nanotube is formed is moved into the post-processing chamber 14.

In the post-processing chamber 14, the substrate K is cooled and inspected.
When this post-processing is completed, the substrate K is moved into the product recovery chamber 15, and a protective film is attached to the upper surface of the substrate K, and the substrate K is taken up by the take-up roll 17. That is, the substrate K on which the carbon nanotubes are formed is collected as a product. When all the substrates K on which the carbon nanotubes are formed are taken up by the take-up roll 17, they are taken out to the outside.

  According to the configuration of the thermal CVD apparatus, when the substrate K is introduced into the heating chamber 13 and the raw material gas G is introduced to form carbon nanotubes on the surface, the substrate K wound around the unwinding roll 16 is wound. Since the carbon nanotubes are wound around the take-up roll 17 and the carbon nanotubes are formed on the surface of the substrate K in the middle thereof, the carbon nanotubes can be continuously formed on the substrate K although each predetermined length. Therefore, the carbon nanotubes can be formed efficiently compared to the case of forming the carbon nanotubes in a complete batch type.

  In addition, the surface on which the carbon nanotubes are formed is curved in an arc shape, and the discharge port 5 of the gas introduction nozzle 9 is located at the center of the arc, so that any portion of the arc-shaped surface is The distances from the discharge port 5 (the source gas G movement distance) are equal, and the source gas G concentration on the surface of the substrate K is uniform. Further, since the curved surface including the heating element 22 has a circular arc shape that is concentric with the substrate K when viewed from the side, since the heating to the substrate K is made uniform, the reaction of the source gas G is also uniform. To be done. Therefore, the carbon nanotube film to be formed can be made uniform.

  Further, since the discharge port 5 is located on the inner peripheral side of the substrate K held in an arc shape, the substrate K is shaped so as to cover the space from which the source gas G is released. Can be efficiently supplied, and carbon nanotubes can be formed more efficiently.

  In addition, since the heating element 22 is arranged on the upper surface (outer periphery) side opposite to the carbon nanotube formation surface of the substrate K, the reaction by the raw material gas G is performed smoothly. This is because the heating element 22 directly warms the substrate K and the source gas G is supplied from the surface opposite to the heating element 22, so that the source gas G is supplied to the substrate K first and gas decomposition occurs in the vicinity of the substrate K. Because it occurs. Note that when the source gas G passes through the heating element 22, gas is decomposed in the vicinity thereof, soot is easily generated at a location where the temperature changes from a high temperature to a low temperature, and at the same time, carbon supplied to the substrate K is small. turn into.

  Further, since the inside of the heating chamber 13 is depressurized, the diffusibility of the source gas G is improved (excellent), so that the source gas G can be uniformly supplied to the entire inner peripheral surface of the substrate K, in other words, the gas Since it becomes difficult to be influenced by the flow, it leads to improvement of product quality, and carbon nanotubes can be formed even for complicated shapes as long as the catalyst particles adhere to the substrate K.

K substrate 1 heating furnace 2 furnace body 2a bottom wall portion 2b upper wall portion 3 partition wall 4 heat insulating material 5 discharge port 6 gas discharge port 7 gas discharge port 9 gas introduction nozzle 11 substrate supply chamber 12 pretreatment chamber 13 heating chamber 14 rear Processing chamber 15 Substrate recovery chamber 16 Unwinding roll 17 Winding roll 21 Heating device 22 Heating element 23 Guide plate 23a Rotating surface 23b Outer peripheral surface 24 Rotating shaft 25 Pressing roller 26 Bracket

Claims (3)

A CVD apparatus having a heating chamber for depositing a deposition material on the surface of a substrate by thermal chemical vapor deposition,
A substrate holding means capable of holding a substrate having a predetermined width in the heating chamber so as to have an arc shape when viewed from the side is provided, and a vapor deposition material discharge port is provided at the center of the arc of the substrate held by the substrate holding means. A CVD apparatus characterized by being arranged along a width direction of a substrate. A CVD apparatus having a heating chamber for depositing a deposition material on the surface of a substrate by thermal chemical vapor deposition,
A substrate holding means capable of holding a substrate having a predetermined width that is moved in the heating chamber in a predetermined direction so as to have an arc shape when viewed from the side, and is deposited at a center position of the arc of the substrate held by the substrate holding means. A CVD apparatus characterized by disposing material discharge ports along the width direction of the substrate. The CVD apparatus according to claim 1, wherein a heating member is disposed along the outer periphery of the guiding rotator.

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