Patent Description:
Known examples of a coating device for forming a coating film such as a diamond thin film on a surface of a base material include a hot filament CVD device. In such a hot filament CVD device, a mixed gas of hydrocarbons (methane) and hydrogen is preheated by a filament heated to <NUM> degrees or more, and the heated gas is introduced into the surface of the substrate to deposit diamond due to thermal decomposition of the hydrocarbons.

<CIT> discloses a technique in which a workpiece (base material) is disposed inside a filament wound in a cylindrical shape to deposit a uniform diamond film on a surface of the workpiece having a three-dimensional shape. The technique uses a structural member including multiple struts and a beam in the shape of a ring connecting the multiple struts. A single filament is stretched around the struts and the beam of the structural member to form a heating region in a cylindrical shape.

In the technique described in <CIT>, the base material (workpiece) is disposed inside the heating region in a cylindrical shape at the time of coating treatment. In such a structure, it is difficult to dispose multiple base materials in the heating region in a cylindrical shape for the purpose of improving coating treatment efficiency. When the base materials are each a heavy object such as a cemented carbide tool, there is a problem in that a large amount of time is required for preparatory work for disposing the multiple base materials in the heating region.

<CIT> discloses a hot filament CVD device as specified in the preamble of claim <NUM>. In the technique described in <CIT>, a movable platform is inserted into a chamber including a chamber body provided with an opening. The movable platform includes a flange plate assembly for sealing the opening, a water-cooled platform, multiple hot filaments to be disposed together with the water-cooled platform inside the chamber, and multiple fixing blocks mounted on the water-cooled platform to support multiple base materials.

It is an object of the present invention to provide a hot filament CVD device capable of easily disposing multiple base materials in a chamber.

The present invention provides a hot filament CVD device as specified in claim <NUM>.

Hereinafter, a hot filament CVD device <NUM> according to an embodiment of the present invention will be described with reference to the drawings. <FIG> is a perspective view of the hot filament CVD device <NUM> according to the present embodiment. <FIG> are respectively a perspective view, a front view, and a plan view, illustrating the internal structure of the hot filament CVD device <NUM>. <FIG> illustrates a chamber <NUM> described later that is partially eliminated.

The hot filament CVD device <NUM> performs coating treatment on multiple workpieces <NUM> (base materials). The workpieces <NUM>, for example, are each a drill blade in the present embodiment. As a material of each of the workpieces <NUM>, cemented carbide is typically used. A hot filament CVD method is for forming a thin film using a product of thermal decomposition or a chemical reaction. The hot filament CVD method is a type of chemical vapor deposition (CVD) and uses a decomposition product or a chemical reaction of a material gas due to thermal energy emitted by a filament. The hot filament CVD device <NUM> can be suitably used for forming a carbon-based thin film, particularly a diamond thin film (polycrystalline diamond thin film). In the present embodiment, the hot filament CVD device <NUM> forms a diamond thin film on a surface of each of the workpieces <NUM> by the hot filament CVD method. As a material gas for forming such a diamond thin film, a mixed gas is used in which a carbon compound gas such as a hydrocarbon and a hydrogen gas are mixed. In the present embodiment, a mixed gas composed of <NUM>% methane and <NUM>% hydrogen by volume is used.

The hot filament CVD device <NUM> includes the chamber <NUM> having an internal space. The chamber <NUM> has a chamber body <NUM> and a door (not illustrated). The chamber body <NUM> defines the above internal space. The chamber body <NUM> includes a bottom <NUM>, four (multiple) legs <NUM>, a front flange <NUM>, a right wall <NUM>, a top plate <NUM>, a left wall <NUM>, and a rear wall <NUM> (<FIG> and <FIG>). The front flange <NUM> is provided with an opening <NUM>. The door (not illustrated) is attached to the chamber body <NUM> in an openable and closable manner. The door, when closed, seals the opening <NUM>. The door, when opened, opens the opening <NUM>. The four legs <NUM> each have a lower end extended downward from the bottom <NUM>. Each of the legs <NUM> has an air cylinder structure and can be extended and contracted. Each of the legs <NUM> has an upper end that is disposed inside the chamber <NUM> and connected to a stage <NUM> described later. The internal space of the chamber <NUM> communicates with a vacuum pump (not illustrated) to cause the internal space of the chamber <NUM> to be in a vacuum or a substantially vacuum state during the coating treatment.

The hot filament CVD device <NUM> further includes the stage <NUM>, multiple workpiece support blocks <NUM> (base material supports) for supporting the respective multiple workpieces <NUM>, a filament electrode unit <NUM> (filament unit), a fixed electrode <NUM>, a movable electrode <NUM>, a left support <NUM>, and a right support <NUM>.

The stage <NUM> is disposed horizontally inside the chamber <NUM> and supports the multiple workpiece support blocks <NUM>. The stage <NUM> has a rectangular shape in plan view, and the legs <NUM> described above are connected to four corners of a lower surface of the stage <NUM>. When each of the legs <NUM> is extended and contracted by a stage drive unit <NUM> described later, the stage <NUM> moves up and down inside the chamber <NUM>. The stage <NUM> includes a table <NUM> in a rectangular shape in top view. The table <NUM> is formed with a fixing portion <NUM> in a recessed shape to allow the multiple workpiece support blocks <NUM> to be disposed without gaps in the left-right direction.

Each of the multiple workpiece support blocks <NUM> has a rectangular parallelepiped shape (strip shape) elongated in a front-rear direction. Each of the multiple workpiece support blocks <NUM> can be inserted into the chamber <NUM> through the opening <NUM> of the chamber <NUM> in the insertion direction (refer to arrow DS in <FIG>). Each of the workpiece support blocks <NUM> has multiple support holes <NUM> (refer to <FIG>) (holes, base material holding parts), which are opened (formed) in its upper surface and into each of which a workpiece <NUM> can be inserted in a vertical direction and can be held. Specifically, each of the workpiece support blocks <NUM> is provided with two rows of groups of the multiple support holes <NUM> at an interval in the left-right direction, and each of the groups of multiple support holes <NUM> includes the multiple support holes <NUM> disposed at intervals in the front-rear direction. At this time, the intervals in the front-rear direction of the multiple support holes <NUM> are set evenly. As a result, the multiple workpiece support blocks <NUM> support the corresponding multiple workpieces <NUM> so that the multiple workpieces <NUM> are disposed at intervals in the insertion direction.

The table <NUM> described above has a mounting surface that allows the multiple workpiece support blocks <NUM> to be mounted allowing the multiple workpieces <NUM> to be disposed facing the corresponding multiple filaments <NUM>. Then, the table <NUM> supports the multiple workpiece support blocks <NUM> so that the multiple workpiece support blocks <NUM> are disposed adjacent to each other in a chamber width direction (left-right direction in <FIG>) intersecting a predetermined insertion direction (refer to arrow DS in <FIG>) inside the chamber <NUM>. In particular, in the present embodiment, the table <NUM> has a body part <NUM> having the mounting surface, a restriction portion 31T (standing wall), and paired side walls 31R. The restriction portion 31T restricts the multiple workpiece support blocks <NUM> in the insertion direction by being in contact with a leading end in the insertion direction of each of the multiple workpiece support blocks <NUM> mounted on the mounting surface of the table <NUM>. The paired side walls 31R are in contact with respective side surfaces of paired workpiece support blocks <NUM> located at respective opposite ends in the left-right direction among the multiple workpiece support blocks <NUM> mounted on the mounting surface of the table <NUM>. Then a distance between the paired side walls 31R in the left-right direction is set so that the multiple workpiece support blocks <NUM> are brought into contact with each other in the left-right direction to restrict the multiple workpiece support blocks <NUM> in the left-right direction.

As illustrated in <FIG> and <FIG>, the filament electrode unit <NUM> is disposed above the stage <NUM> (multiple workpieces <NUM>) inside the chamber <NUM>. The filament electrode unit <NUM> includes multiple filaments <NUM> (<FIG>). Structure of the filament electrode unit <NUM> will be described in more detail later.

The fixed electrode <NUM> and the movable electrode <NUM> are disposed inside the chamber <NUM>. As illustrated in <FIG> and <FIG>, the fixed electrode <NUM> and the movable electrode <NUM> are disposed extending in the front-rear direction. The fixed electrode <NUM> is electrically connected to a left end (one end in a first direction) of each of the multiple filaments <NUM>. In contrast, the movable electrode <NUM> is electrically connected to a right end (the other end in the first direction) of each of the multiple filaments <NUM>. The fixed electrode <NUM> and the movable electrode <NUM> are electrically connected to a heating power source <NUM> described later. Upon receiving electric power of the heating power source <NUM>, the fixed electrode <NUM> and the movable electrode <NUM> allow a predetermined current to flow between the left end and the right end of each of the multiple filaments <NUM>. As a result, the multiple filaments <NUM> are heated.

The left support <NUM> and the right support <NUM> support the fixed electrode <NUM> and the movable electrode <NUM>, respectively. The left support <NUM> and the right support <NUM> electrically connect the heating power source <NUM> and the filament electrode unit <NUM>. Thus, electrical wiring (not illustrated) is provided inside the left support <NUM> and the right support <NUM>. The left support <NUM> includes a left outer support <NUM> exposed to the outside of the chamber <NUM> and a left inner support <NUM> located inside the chamber <NUM> (<FIG>). Similarly, the right support <NUM> includes a right outer support <NUM> exposed to the outside of the chamber <NUM> and a right inner support <NUM> located inside the chamber <NUM>. In the present embodiment, the right inner support <NUM> of the right support <NUM> includes an extendable cylinder structure. The right inner support <NUM> extends and contracts inside the chamber <NUM> in response to a driving force generated by an electrode drive unit <NUM> (<FIG>) described later. As a result, the movable electrode <NUM> can be moved in the left-right direction inside the chamber <NUM> (refer to arrow DR in <FIG>).

As illustrated in <FIG> and <FIG>, through holes <NUM> and <NUM> through which the left support <NUM> and the right support <NUM> pass are opened in the right side wall <NUM> and the left side wall <NUM> of the chamber <NUM>, respectively. Gaps between the through holes and the corresponding supports are sealed with a sealing material (not illustrated). <FIG> is an electrical block diagram of the hot filament CVD device <NUM> according to the present embodiment. The hot filament CVD device <NUM> further includes a control unit <NUM>. The control unit <NUM> comprehensively controls operation of the hot filament CVD device <NUM>, and is electrically connected to transmission-reception destinations of a control signal, such as the heating power source <NUM>, the electrode drive unit <NUM>, the stage drive unit <NUM> (moving mechanism), an operation unit <NUM>, and a display <NUM>. The control unit <NUM> is also electrically connected to other units provided in the hot filament CVD device <NUM>. The hot filament CVD device <NUM> also includes a control unit of a gas flow rate (not illustrated), and the like.

The heating power source <NUM> allows a predetermined current to flow through the fixed electrode <NUM> and the movable electrode <NUM> so that the multiple filaments <NUM> are heated to about <NUM> to <NUM>. For the heating power source <NUM>, a high-frequency pulse power source having stable DC characteristics is desirably used.

The electrode drive unit <NUM> includes a motor and a gear mechanism (not illustrated). The electrode drive unit <NUM> generates a driving force for moving the movable electrode <NUM> inside the chamber <NUM>. The electrode drive unit <NUM> is connected to the right support <NUM>.

The stage drive unit <NUM> includes a motor and a gear mechanism (not illustrated). The stage drive unit <NUM> generates a driving force for moving the stage <NUM> up and down inside the chamber <NUM>. The stage drive unit <NUM> is connected to the four legs <NUM>.

The operation unit <NUM> is formed of an operation panel (not illustrated) and accepts various operations for controlling the hot filament CVD device <NUM>.

The display <NUM> is formed of a liquid crystal panel (not illustrated) and displays information on various movements of the hot filament CVD device <NUM>, for example.

The control unit <NUM> is configured by a central processing unit (CPU), a read only memory (ROM) for storing a control program, a random access memory (RAM) used as a work area of the CPU, and the like, and operates to functionally include a power source control unit <NUM>, a drive control unit <NUM>, a calculation unit <NUM>, a determination unit <NUM>, a storage unit <NUM>, and an output unit <NUM>, when the CPU executes the control program.

The power source control unit <NUM> controls the heating power source <NUM> according to operation information input to the operation unit <NUM>. The power source control unit <NUM> controls output (kW), heating time, and the like of the heating power source <NUM>.

The drive control unit <NUM> causes the electrode drive unit <NUM> according to the operation information input to the operation unit <NUM> to move the movable electrode <NUM> to left and right. The drive control unit <NUM> causes the stage drive unit <NUM> according to the operation information input to the operation unit <NUM> to move the stage <NUM> up and down.

The calculation unit <NUM> calculates the amount of thermal expansion of the filaments <NUM> in accordance with heating time of the filaments <NUM>. The calculation unit <NUM> also calculates the amount of movement setting of the movable electrode <NUM> based on the amount of thermal expansion.

The determination unit <NUM> determines disconnection of the filaments <NUM> based on change in a current value of the heating power source <NUM>. When the determination unit <NUM> determines that the filament <NUM> is disconnected, information on the disconnection is displayed on the display <NUM>.

The storage unit <NUM> stores various parameters, threshold information, and the like for controlling the hot filament CVD device <NUM>. As an example, the storage unit <NUM> stores parameters for the calculation unit <NUM> to calculate the amount of thermal expansion of each of the filaments <NUM>.

The output unit <NUM> outputs various command signals according to the control of the heating power source <NUM> and the electrode drive unit <NUM>, being performed by the power source control unit <NUM> and the drive control unit <NUM>.

Next, structure of multiple filament cartridges according to the present embodiment will be described in more detail. <FIG> and <FIG> are each a perspective view of the filament electrode unit <NUM> including the multiple cartridges according to the present embodiment. <FIG> is a sectional view of a connecting member <NUM> of the filament electrode unit <NUM>.

In the present embodiment, the filament electrode unit <NUM> includes a first cartridge 6A, a second cartridge 6B, and a third cartridge 6C (multiple filament cartridges). The first cartridge 6A, the second cartridge 6B, and the third cartridge 6C each have the same structure. Each of the cartridges can be mounted inside the chamber <NUM> through the opening <NUM> (<FIG>) with the door open. Hereinafter, the structure of the first cartridge 6A will be described as an example. The first cartridge 6A includes the multiple filaments <NUM>, a left frame <NUM> (filament holding mechanism), a right frame <NUM> (filament holding mechanism), and paired connecting members <NUM>. Each of the cartridges can be mounted in the chamber <NUM> even when it is flipped horizontally.

The multiple filaments <NUM> (<FIG>) extend in the left-right direction (first direction) and are disposed apart from each other in the front-rear direction (second direction intersecting the first direction). For each of the filaments <NUM>, a wire made of a refractory metal such as tungsten or tantalum, having a wire diameter of <NUM> to <NUM>, is used. Each of the filament cartridges is provided with <NUM> filaments <NUM>.

The left frame <NUM> is a member extending in the front-rear direction and supports left ends of the multiple filaments <NUM>. The left frame <NUM> includes a left frame front end portion <NUM>, a left frame rear end portion <NUM>, and multiple filament engaging portions <NUM>. The left frame front end portion <NUM> is disposed at a front end of the left frame <NUM> and supports a left end portion of the connecting member <NUM> on a front side. The left frame rear end portion <NUM> is disposed at a rear end of the left frame <NUM> and supports a left end portion of the connecting member <NUM> on a rear side. The multiple filament engaging portions <NUM> each engage a left end portion of the corresponding one of the filaments <NUM> (refer to <FIG>). When the left frame <NUM> is supported by the fixed electrode <NUM>, the left end portion of each of the filaments <NUM> and the heating power source <NUM> are electrically connected to each other through the corresponding one of the filament engaging portions <NUM>.

Similarly, the right frame <NUM> is a member extending in the front-rear direction and supports right ends of the multiple filaments <NUM>. The right frame <NUM> includes a right frame front end portion <NUM>, a right frame rear end portion <NUM>, and multiple filament engaging portions (not illustrated, similar to the filament engaging portions <NUM> described above). The right frame front end portion <NUM> is disposed at a front end of the right frame <NUM> and supports a right end portion of the connecting member <NUM> on the front side. The right frame rear end portion <NUM> is disposed at a rear end of the right frame <NUM> and supports a right end portion of the connecting member <NUM> on the rear side. The multiple filament engaging portions each engage a right end portion of the corresponding one of the filaments <NUM>. When the right frame <NUM> is supported by the movable electrode <NUM>, the right end portion of each of the filaments <NUM> and the heating power source <NUM> are electrically connected to each other through the corresponding one of the filament engaging portions.

The paired connecting members <NUM> connects respective opposite ends of the left frame <NUM> in the front-rear direction and corresponding opposite ends of the right frame <NUM> therein in the left-right direction. With reference to <FIG> and <FIG>, each of the connecting members <NUM> includes a first support rod <NUM> and a second support rod <NUM> that are made of metal, and an insulating bush <NUM>. The first support rod <NUM> includes a small diameter portion 631A and a large diameter portion 631B. The second support rod <NUM> includes a leading end portion 632A. As illustrated in <FIG>, the large diameter portion 631B of the first support rod <NUM> is formed with a cavity in a cylindrical shape. The insulating bush <NUM> has a cylindrical shape and is preliminarily fitted into the cavity of the large diameter portion 631B. As illustrated in <FIG>, the leading end portion 632A of the second support rod <NUM> is inserted into the insulating bush <NUM> in the first support rod <NUM>. The insulating bush <NUM> is made of an insulating material such as ceramic, and prevents electric discharge between the first support rod <NUM> and the second support rod <NUM>. The insulating bush <NUM> has high slidability to the leading end portion 632A made of metal, and thus can reduce a drive load applied to the electrode drive unit <NUM> due to telescopic movement of each of the connecting members <NUM>. As described above, when the movable electrode <NUM> is moved left and right using a driving force generated by the electrode drive unit <NUM>, the right frame <NUM> and the pair of front and rear second support rods <NUM>, being connected to the movable electrode <NUM>, move following the movable electrode <NUM>. At this time, the leading end portion 632A of each of the second support rods <NUM> slides inside the insulating bush <NUM>. As described above, in the present embodiment, the first cartridge 6A, the second cartridge 6B, and the third cartridge 6C each hold the multiple filaments <NUM> in parallel, and each of the connecting members <NUM> can be extended and contracted in a direction in which the filaments <NUM> extend. The large diameter portion 631B of the first support rod <NUM> and the leading end portion 632A of the second support rod <NUM> constitute a telescopic portion <NUM> (<FIG>) of the present invention. When receiving a driving force of the electrode drive unit <NUM> from the right support <NUM>, the telescopic portion <NUM> extends and contracts allowing a change in distance between the left frame <NUM> and the right frame <NUM>.

<FIG> is a front view illustrating an internal structure of the hot filament CVD device <NUM> according to the present embodiment, and is a front view of a state in which the filament electrode unit <NUM> is detached. <FIG> is a perspective view illustrating a state in which each cartridge of the filament electrode unit <NUM> is mounted on the fixed electrode <NUM> and the movable electrode <NUM>. <FIG> is a perspective view illustrating a state in which each cartridge of the filament electrode unit <NUM> is held by the fixed electrode <NUM> and the movable electrode <NUM>. <FIG> is a sectional view of the fixed electrode <NUM> of the hot filament CVD device <NUM>, and <FIG> is a sectional view of a state in which each cartridge of the filament electrode unit <NUM> is held by the fixed electrode <NUM>.

In the present embodiment, the fixed electrode <NUM> and the movable electrode <NUM> each include a holding part for holding the filament electrode unit <NUM>. The fixed electrode <NUM> and the movable electrode <NUM> are bilaterally symmetrical in shape, so that the fixed electrode <NUM> will be described below as an example. As illustrated in <FIG>, the fixed electrode <NUM> has a U-shape turned sideways, opening to the right, in section. In other words, the fixed electrode <NUM> includes an engaging recess <NUM> (holding part). The engaging recess <NUM> is formed throughout the fixed electrode <NUM> in the front-rear direction. The engaging recess <NUM> has an upper end portion formed with an electrode upper engaging portion 71J. The engaging recess <NUM> has a lower end portion formed with an electrode lower engaging portion <NUM>. The electrode upper engaging portion 71J has a triangular shape in section and is defined by an upper inclined portion 71J1 and an upper inner portion 71J2. Similarly, the electrode lower engaging portion <NUM> has a triangular shape in section and is defined by a lower inclined portion 71K1 and a lower inner portion 71K2. As illustrated in <FIG>, the upper inclined portion 71J1 and the lower inclined portion 71K1 are parallel to each other and are inclined downward (to the left) toward the inside of the engaging recess <NUM>. Further, the fixed electrode <NUM> and the movable electrode <NUM> form a part of the filament holding mechanism of the present invention.

Then, with reference to <FIG>, the left frame <NUM> of each of the first cartridge 6A, the second cartridge 6B, and the third cartridge 6C has a shape that can be fitted into the engaging recess <NUM> of the fixed electrode <NUM>. That is, the left frame <NUM> has an upper left end portion formed with an upper protrusion 61A and a lower left end portion formed with a lower protrusion 61B. A lower recess 61C is formed on the right of the lower protrusion 61B. The upper protrusion 61A and the lower protrusion 61B have inclined surfaces that are respectively in contact with the upper inclined portion <NUM> and the lower inclined portion 71K1 (<FIG>).

A case will be described in which the first cartridge 6A, the second cartridge 6B, and the third cartridge 6C are combined overlapping each other in advance as illustrated in <FIG>, and the filament electrode unit <NUM> is integrally attached to the fixed electrode <NUM> and the movable electrode <NUM>. As illustrated in <FIG>, when the upper protrusion 61A of the first cartridge 6A is fitted into the lower recess 61C of the second cartridge 6B, and the upper protrusion 61A of the second cartridge 6B is fitted into the lower recess 61C of the third cartridge 6C, the three cartridges are connected to each other. The same applies to the movable electrode <NUM> and the right frame <NUM>. Then, the first cartridge 6A is inserted into the chamber <NUM> along the fixed electrode <NUM> while the lower protrusion 61B of the first cartridge 6A located at the lowermost position of the filament electrode unit <NUM> is fitted into the electrode lower engaging portion <NUM> (<FIG>) of the fixed electrode <NUM>. At this time, the right frame <NUM> of the first cartridge 6A is also inserted into the chamber along the movable electrode <NUM> using a similar structure. In contrast, the third cartridge 6C is inserted into the chamber <NUM> along the fixed electrode <NUM> while the upper protrusion 61A of the third cartridge 6C located at the uppermost position of the filament electrode unit <NUM> is fitted into the electrode upper engaging portion 71J (<FIG>) of the fixed electrode <NUM>. At this time, the right frame <NUM> of the third cartridge 6C is also inserted into the chamber along the movable electrode <NUM> using a similar structure. The first cartridge 6A, the second cartridge 6B, and the third cartridge 6C of the filament electrode unit <NUM> may be inserted into the chamber <NUM> in this order from below as illustrated in <FIG> and <FIG>.

As described above, in the present embodiment, the fixed electrode <NUM> and the movable electrode <NUM> each have a shape for guiding the first cartridge 6A, the second cartridge 6B, and the third cartridge 6C that are inserted into the internal space of the chamber <NUM> through the opening <NUM> in a mounting direction (arrow DS in <FIG>) parallel to the front-rear direction. The fixed electrode <NUM> and the movable electrode <NUM> respectively hold the left frame <NUM> and the right frame <NUM> of each of the cartridges such that the multiple filaments <NUM> face the corresponding multiple workpieces <NUM> in the vertical direction (a third direction intersecting a plane including the first direction and the second direction) (<FIG> and <FIG>). Then, the multiple filaments <NUM> of each of the first cartridge 6A, the second cartridge 6B, and the third cartridge 6C mounted in the chamber <NUM> are disposed at intervals in the vertical direction. As a result, a space is formed between the filaments <NUM> adjacent to each other in the left-right direction, the space passing through the first cartridge 6A, the second cartridge 6B, and the third cartridge 6C in the vertical direction. At the time of the coating treatment, the workpieces <NUM> supported by the workpiece support blocks <NUM> are inserted into the space as described later.

<FIG> is a perspective view illustrating an internal structure of the hot filament CVD device <NUM> according to the present embodiment, and is a perspective view illustrating a state of mounting the workpiece support blocks <NUM> on the stage <NUM>. <FIG> is a plan view illustrating the internal structure of the hot filament CVD device <NUM>, and is a plan view illustrating a state of mounting the workpiece support blocks <NUM> on the stage <NUM>. As described above, the stage <NUM> includes the table <NUM>. The table <NUM> is formed with the fixing portion <NUM> in a recessed shape (<FIG>). The fixing portion <NUM> has a width in the left-right direction that corresponds to a length acquired by adding a slight gap fitting tolerance to the sum of widths of the multiple (<NUM>) workpiece support blocks <NUM> in the left-right direction. When each of the workpieces <NUM> is a drill blade, the drill blade has a heavy weight, and thus it is difficult to place many workpieces <NUM> on the table <NUM> at one time. In the present embodiment, as illustrated in <FIG> and <FIG>, the multiple workpiece support blocks <NUM> each have a rectangular parallelepiped shape extending in the front-rear direction, so that the multiple workpieces <NUM> (<FIG>) distributed throughout the table <NUM> can be divided and placed on the table <NUM>. The fixing portion <NUM> in a recessed shape has a function of positioning the multiple workpiece support blocks <NUM> in the left-right direction. The table <NUM> includes a restriction portion 31T (<FIG> and <FIG>) (standing wall) disposed at a rear end of the fixing portion <NUM>. The restriction portion 31T is a wall portion extending in the left-right direction, and regulates a rear end position of each of the workpiece support blocks <NUM> by being in contact with the multiple workpiece support blocks <NUM>. As a result, positions of the multiple workpieces <NUM> supported on the corresponding multiple workpiece support blocks <NUM> in the front-rear and left-right directions are restricted. In other words, the multiple support holes <NUM> (<FIG>) formed in each workpiece support block <NUM> are opened in the workpiece support block <NUM> such that the multiple workpieces <NUM> are disposed between the corresponding multiple filaments <NUM> of each cartridge of the filament electrode unit <NUM> held by the fixed electrode <NUM> and the movable electrode <NUM> when viewed from the vertical direction (third direction). Then, the fixing portion <NUM> of the table <NUM> restricts positions of the respective workpiece support blocks <NUM> such that the multiple workpieces <NUM> are disposed between the corresponding multiple filaments <NUM>.

<FIG> is a front view illustrating the internal structure of the hot filament CVD device <NUM> according to the present embodiment, and is a front view illustrating a state of raising the table <NUM> (stage <NUM>). <FIG> is a perspective view illustrating the internal structure of the hot filament CVD device <NUM>, and is a perspective view illustrating a state in which the table <NUM> is raised. Further, <FIG> is a front view illustrating the internal structure of the hot filament CVD device <NUM>, and is a front view illustrating a state in which the table <NUM> is raised.

As described above, the coating treatment to the multiple workpieces <NUM> is prepared such that the filament electrode unit <NUM> is mounted on the fixed electrode <NUM> and the movable electrode <NUM>, and the multiple workpiece support blocks <NUM> supporting the corresponding multiple workpieces <NUM> are mounted on the table <NUM>. When the door (not illustrated) is closed, the inside of the chamber <NUM> is evacuated by the vacuum pump and the mixed gas is introduced. When the operator operates the operation unit <NUM> (<FIG>), the stage drive unit <NUM> moves the stage <NUM> upward (arrow DT in <FIG> and <FIG>). As a result, the multiple workpieces <NUM> are positioned between the corresponding multiple filaments <NUM> in a plane including the front-rear direction and the left-right direction. In the present embodiment, as illustrated in <FIG>, upward movement of the stage <NUM> is controlled such that the tip of each of the workpieces <NUM> is located between the filament <NUM> of the third cartridge 6C and the filament <NUM> of the second cartridge 6B.

Next, when the power source control unit <NUM> causes the heating power source <NUM> to allow a current to flow into the fixed electrode <NUM> and the movable electrode <NUM> in response to operator's operation, heating of the multiple filaments <NUM> is started. Then, each of the filaments <NUM> thermally expands with the heating. In the present embodiment, the electrode drive unit <NUM> can move the movable electrode <NUM> in the left-right direction (extending direction of the filaments <NUM>) as described above. The calculation unit <NUM> calculates the amount of thermal expansion ΔL (mm) of each of the filaments <NUM> from Equation <NUM>.

In Equation <NUM>, α is a coefficient of thermal expansion for each material, T1 is room temperature (°C), T2 is the temperature of the filaments <NUM> measured with a radiation thermometer, and L (mm) is an original length of each of the filaments <NUM>.

Then, the drive control unit <NUM> causes the electrode drive unit <NUM> to move the movable electrode <NUM> to the right (in the direction of pulling the filaments <NUM>) by the amount of thermal expansion calculated by the calculation unit <NUM>. At this time, in the present embodiment, the movable electrode <NUM> is moved by the amount of thermal expansion of the filaments <NUM>, so that no extra tension is applied to the filaments <NUM>. As a result, a central portion of each of the filaments <NUM> is prevented from hanging downward (deforming) due to the thermal expansion of each of the filaments <NUM>. Such movement control of the movable electrode <NUM> (attitude control of the filaments <NUM>) is mainly performed in an initial stage of heating where the temperature of the filaments <NUM> rises. Such control may be continued throughout coating treatment time for the workpieces <NUM>.

When each of the filaments <NUM> reaches a predetermined heating temperature in accordance with input power of the heating power source <NUM>, the filaments <NUM> heat the material gas in the chamber <NUM>, and then graphite and other non-diamond carbons react with atomic hydrogen and evaporate. Here, the atomic hydrogen reacts with an original hydrocarbon gas (methane) to form carbon-hydrogen species with high reactivity. When this species decomposes, hydrogen is released, pure carbon or diamond is formed, and a diamond film is formed on each of the workpieces <NUM>.

As described above, in the present embodiment, the central portion of each of the filaments <NUM> is prevented from hanging downward during the coating treatment, so that a distance between each of the filaments <NUM> and the corresponding one of the workpieces <NUM> is prevented from varying in a longitudinal direction (left-right direction) of each of the filaments <NUM>. This prevents fluctuation in deposition speed of each of the workpieces <NUM> and variation in deposition result (film thickness, uniformity) from occurring depending on a position on the table <NUM>. When multiple filaments <NUM> are disposed adjacent to each other in the vertical and front-rear directions in the chamber <NUM> as in the present embodiment, direct measurement of temperature of each of the filaments <NUM> using a conventional radiation thermometer is likely to cause measurement accuracy to deteriorate. Additionally, each of the filaments <NUM> has a small diameter. This causes measurement of infrared rays and electromagnetic waves emitted to be difficult, and measuring equipment to be expensive. In contrast, in the present embodiment, the amount of thermal expansion of each of the filaments <NUM> is calculated in accordance with output power of the heating power source <NUM>, and the movable electrode <NUM> is moved in accordance with the amount of the thermal expansion. Thus, as compared with a case where temperature of each of the filaments <NUM> is directly measured, control variation is reduced, an attitude of each of the filaments <NUM> is stably maintained, and coating quality for each of the workpieces <NUM> is improved.

As described above, in the present embodiment, the filament cartridges 6A, 6B and 6C supporting the multiple filaments <NUM> are inserted into the chamber <NUM> through the opening <NUM>. At this time, the fixed electrode <NUM> and the movable electrode <NUM> guide each of the filament cartridges, so that each of the filament cartridges can be easily inserted into the chamber <NUM>. The fixed electrode <NUM> and the movable electrode <NUM> also hold each of the filament cartridges in the chamber <NUM> so that the multiple filaments <NUM> face the corresponding multiple workpieces <NUM>. This enables each of the multiple filaments <NUM> to be easily disposed at a coating treatment position inside the chamber <NUM>. Additionally, when a part of the multiple filaments <NUM> is broken, the broken filament <NUM> can be easily removed by replacing the corresponding filament cartridge.

In the present embodiment, multiple filament cartridges can be easily attached inside the chamber <NUM> and detached from inside the chamber <NUM>. The filaments <NUM> of each of the multiple filament cartridges are disposed at intervals in the vertical direction, so that a coating treatment space in which each of the workpieces <NUM> is insertable can be formed between the filaments <NUM> adjacent to each other in the front-rear direction.

In the present embodiment, even when the multiple filaments <NUM> are thermally expanded during the coating treatment, hanging down or deformation of the multiple filaments <NUM> can be prevented by changing a distance between the left frame <NUM> and the right frame <NUM> using the electrode drive unit <NUM>. Each of the paired connecting members <NUM> of each filament cartridge has the telescopic portion <NUM>, so that the above deformation due to thermal expansion can be prevented while cartridge structure of the multiple filaments <NUM> is maintained.

In the present embodiment, the multiple workpiece support blocks <NUM> supporting the corresponding multiple workpieces <NUM> can be inserted into the chamber <NUM> through the opening <NUM>. At this time, the operator can insert the multiple workpiece support blocks <NUM> in the predetermined insertion direction while sliding the workpiece support blocks <NUM> on the mounting surface of the table <NUM>. Thus, even when each of the workpieces <NUM> is a heavy object, the multiple workpieces <NUM> can be easily disposed at respective coating treatment positions facing the corresponding multiple filaments <NUM> inside the chamber <NUM>. The multiple workpiece support blocks <NUM> mounted on the mounting surface are disposed adjacent to each other in the left-right direction (chamber width direction). This enables the multiple workpieces <NUM> to be densely disposed inside the chamber <NUM>.

In the present embodiment, when leading end portions of the respective multiple workpiece support blocks <NUM> come into contact with the restriction portion <NUM>1T, positions of the multiple workpiece support blocks <NUM> and also positions of the multiple workpieces <NUM> supported on the respective workpiece support blocks <NUM> in the insertion direction are restricted. When the multiple workpiece support blocks <NUM> are inserted in order, the workpiece support block <NUM> inserted earlier can guide the adjacent workpiece support block <NUM> to be inserted later. When all the workpiece support blocks <NUM> are inserted, positions of the multiple workpiece support blocks <NUM> and also positions of the multiple workpieces <NUM> supported on the respective workpiece support blocks <NUM> in the chamber width direction are restricted. As a result, the position of each of the workpieces <NUM> is restricted, so that the coating treatment on the workpieces <NUM> can be stably performed.

According to the present embodiment, the filament holding mechanism is provided, which holds the multiple filaments <NUM> so that the multiple filaments <NUM> extend in the first direction parallel to the insertion direction and are disposed apart from each other in the second direction intersecting the first direction, and face the corresponding multiple workpieces <NUM> in the third direction intersecting the plane including the first direction and the second direction inside the chamber <NUM>. Another filament holding mechanism may be provided, which holds the multiple filaments <NUM> in the third direction intersecting the plane including the first direction and the second direction while allowing the multiple filaments <NUM> to face the corresponding multiple workpieces <NUM>, wherein the multiple filaments <NUM> extend in the first direction intersecting the insertion direction and are disposed apart from each other in the second direction intersecting the first direction inside the chamber <NUM>. According to these configurations, a plane including the multiple filaments <NUM> is disposed facing the multiple workpieces <NUM> in the vertical direction (third direction). This enables the coating treatment to be applied to the multiple workpieces <NUM> in a wide range.

In the present embodiment, when the workpieces <NUM> are inserted into the corresponding multiple support holes <NUM> of each of the workpiece support blocks <NUM>, and the workpiece support blocks <NUM> are held on the table <NUM> of the stage <NUM>, a coating treatment position of each of the workpieces <NUM> can be aligned with the corresponding one of the multiple filaments <NUM>.

In the present embodiment, when the stage drive unit <NUM> moves the stage <NUM> including the table <NUM> in the vertical direction, the table <NUM> can be moved between the coating treatment position at which the multiple workpieces <NUM> are held at respective positions close to the corresponding multiple filaments <NUM>, and a separation position at which the multiple workpieces <NUM> are held at respective positions further apart downward from the corresponding multiple filaments <NUM> than the coating treatment position.

Although the hot filament CVD device <NUM> according to an embodiment of the present invention has been described above, the present invention is not limited to the embodiment. As the hot filament CVD device according to the present invention, the following modified embodiments are applicable.

The present invention provides a hot filament CVD device that performs coating treatment on multiple base materials. The hot filament CVD device includes: a chamber including a chamber body provided with an opening, and a door attached to the chamber body to seal the opening and allow the opening to be openable; multiple filaments disposed inside the chamber to heat a material gas; multiple base material supports insertable into the chamber through the opening in a predetermined insertion direction, the multiple base material supports supporting the corresponding multiple base materials while allowing the multiple base materials to be disposed at intervals in the insertion direction; and a table having a mounting surface on which the multiple base material supports are allowed to be mounted allowing the multiple base materials to be disposed facing the corresponding multiple filaments, and supporting the multiple base material supports inside the chamber while allowing the multiple base material supports to be disposed adjacent to each other in a chamber width direction intersecting the insertion direction.

According to the present configuration, the multiple base material supports supporting the corresponding multiple base materials can be inserted into the chamber through the opening. At this time, the operator can insert the multiple base material supports in the predetermined insertion direction while sliding the base material supports on the mounting surface of the table. Thus, the multiple base materials can be easily disposed at respective coating treatment positions facing the corresponding multiple filaments inside the chamber. The multiple base material supports mounted on the mounting surface are disposed adjacent to each other in the chamber width direction. This enables the multiple base materials to be densely disposed inside the chamber.

The above configuration may be configured such that the table includes a body part having the mounting surface, a standing wall that comes into contact with a leading end in the insertion direction of each of the multiple base material supports mounted on the mounting surface to restrict the multiple base material supports in the insertion direction, and paired side walls that are each brought into contact with a side surface of a corresponding one of paired base material supports located at respective opposite ends of the multiple base material supports mounted on the mounting surface in the chamber width direction, a distance between the paired side walls in the chamber width direction being set to bring the multiple base material supports into contact with each other to restrict the multiple base material supports in the chamber width direction.

According to the present configuration, when the leading ends of the respective multiple base material supports come into contact with the standing wall, the multiple base material supports and also the multiple base materials supported on each of the base material supports are restricted in the insertion direction. When the multiple base material supports are inserted in order, the base material support inserted earlier can guide the adjacent base material support to be inserted later. When all the base material supports are inserted, the multiple base material supports and also the multiple base materials supported on each of the base material supports are restricted in the chamber width direction.

The above configuration may further include a filament holding mechanism that holds the multiple filaments so that the multiple filaments extend in the first direction that is any one of the insertion direction and the chamber width direction and are disposed apart from each other in the second direction that is another of the insertion direction and the chamber width direction, and face the corresponding multiple base materials in a third direction intersecting a plane including the first direction and the second direction inside the chamber.

According to the present configuration, a plane including the multiple filaments is disposed facing the multiple base materials in the third direction. This enables the coating treatment to be applied to the multiple base materials in a wide range.

The above configuration is desirably configured such that the multiple base material supports are each provided with multiple base material holding parts in the insertion direction that hold the corresponding multiple base materials, and the multiple base material holding parts in the respective base material supports are located at respective positions at which the multiple base materials are disposed between the corresponding multiple filaments when viewed from the third direction.

According to the present configuration, when the base materials are held by the respective multiple base material holding parts of each of the base material supports, and the base material supports are supported by the table, the multiple base materials can be easily aligned with the corresponding multiple filaments.

The above configuration desirably further includes a moving mechanism that moves the table in the third direction to move the multiple base materials between a coating treatment position at which the multiple base materials are held close to the corresponding multiple filaments and a separation position at which the multiple base materials are held further apart from the multiple filaments than the coating treatment position in the third direction.

Claim 1:
A hot filament CVD device (<NUM>) that is configured to perform coating treatment on multiple base materials (<NUM>), the hot filament CVD device (<NUM>) comprising:
a chamber (<NUM>) including a chamber body (<NUM>) provided with an opening (<NUM>), and a door attached to the chamber body (<NUM>) to seal the opening (<NUM>) and allow the opening (<NUM>) to be openable;
multiple filaments (<NUM>) configured to heat a material gas;
multiple base material supports (<NUM>) insertable into the chamber (<NUM>) through the opening (<NUM>) in a predetermined insertion direction (DS), the multiple base material supports (<NUM>) configured to support the corresponding multiple base materials (<NUM>) while allowing the multiple base materials (<NUM>) to be disposed at intervals in the insertion direction (DS); and
a table (<NUM>) having a mounting surface on which the multiple base material supports (<NUM>) are allowed to be mounted allowing the multiple base materials (<NUM>) to be disposed facing the corresponding multiple filaments (<NUM>), and configured to support the multiple base material supports (<NUM>) inside the chamber (<NUM>) while allowing the multiple base material supports (<NUM>) to be disposed adjacent to each other in a chamber width direction intersecting the insertion direction (DS),
characterized by
a filament cartridge (6A, 6B, 6C) provided with the multiple filaments (<NUM>), wherein
the filament cartridge (6A, 6B, 6C) and the table (<NUM>) are disposed inside the chamber (<NUM>), and
the multiple base material supports (<NUM>) are insertable into the chamber (<NUM>) while sliding the multiple base material supports (<NUM>) on the mounting surface of the table (<NUM>).