JP4986516B2 - Deposited film forming apparatus and deposited film forming method - Google Patents

Description

  The present invention relates to a deposition film forming apparatus and a deposition film forming method for forming a film by using a source gas as a deposition species by a heating element and depositing the deposition species on a deposition object.

  A chemical vapor deposition (CVD) method is often used for film formation of various semiconductor devices. The CVD method includes a plasma CVD method, a thermal CVD method, and a heating element CVD method. Among these CVD methods, the heating element CVD method is a film forming method in which a source gas is decomposed by the heat of the heating element and is formed on a substrate (see, for example, Patent Documents 1-3). Therefore, the heating element CVD method can lower the temperature of the substrate during film formation compared to the thermal CVD method, so that the range of use of the substrate material can be widened, and a film on the substrate can be formed like the plasma CVD method. It has the advantage that it is not damaged by plasma. For these reasons, the heating element CVD method has attracted attention as a film forming method capable of obtaining high-quality films on various substrates.

  As shown in FIG. 16, the general heating element CVD apparatus 9 is configured to form a thin film (deposited film) on the surface (deposition surface) 91 of the substrate 90. In the heating element CVD apparatus 9, the source gas is supplied to the film forming chamber 93 by the gas supply means (not shown) while the base 90 is held by the base holder 92, while the source gas is supplied to the plurality of heating elements 94. A film is formed by decomposing and depositing the decomposition component at that time on the surface of the substrate 90.

  The plurality of heating elements 94 are linear wires, and when the deposition surface 91 is planar, as shown in FIG. 17, they are arranged side by side so that their axes are parallel to each other. . Adjacent heating elements 94 are connected to each other by a conductor 95, and the plurality of heating elements 94 are electrically arranged in series as a whole.

Japanese Patent No. 2692326 JP 2005-48273 A JP 2005-133162 A

  However, in the heating element CVD apparatus 9, gas species activated in substantially the same direction are emitted from the surface of the heating element 94 toward the periphery. Therefore, a deposited film is formed in addition to the deposition surface 91. In order to supply gas uniformly to the surface of the catalyst body, a shower-like gas supply head 96 is often provided. However, since this surface is close to the catalyst body in distance, there is a problem that a film is particularly easily attached. It was.

When a deposited film is formed on a surface other than the deposition surface 91, the deposited film may be peeled off, leading to a film formation defect. Therefore, it is necessary to remove the deposited film adhering to other than the deposition surface 91 by cleaning using an etching gas such as nitrogen trifluoride (NF ₃ ) or chlorine trifluoride (ClF ₃ ). Then, it leads to the tact down of film formation.

  On the other hand, in order to suppress the formation of a deposited film other than the deposition target surface 91, a method of supplying gas from a position relatively far from the catalyst body has been proposed. However, since it is difficult to uniformly supply the catalyst to the catalyst body, the film thickness tends to be non-uniform, and the film thickness tends to be thin and the film forming speed is low. Further, as means for increasing the film forming speed, means such as increasing the number of catalyst bodies and increasing the gas pressure can be considered, but if such means are employed, the film thickness distribution is further deteriorated. On the other hand, in recent years, it is desired to construct a technique capable of forming a uniform film over a large area for a large screen flat display or a solar cell.

  An object of the present invention is to make it possible to form a film having a uniform thickness while reducing the frequency of cleaning the inside of the apparatus using an etching gas or the like.

In the first aspect of the present invention, a film formation chamber for accommodating a deposition film formation target, source gas supply means for supplying a source gas to the film formation chamber, and the source gas as a deposition species A deposition film forming apparatus comprising: one or a plurality of heating elements for performing the operation; and a gas supply head for releasing the source gas and the deposition species toward the deposition film formation target, The body includes an internal space through which the source gas supplied by the source gas supply means passes, and at least a part of the source gas passing therethrough is decomposed to become a deposited species, and the deposited species present in the inner space together and a one or more outlet for discharging toward the deposited film forming object, characterized in that it also serves as the gas supply head, the deposited film forming apparatus is provided.

  The heating element is formed in a cylindrical shape, for example. Preferably, the heating element is a hollow wire. The hollow wire has, for example, a wire shape. In this case, the plurality of heating elements are arranged side by side so that their axial centers are parallel or substantially parallel to each other.

  When the surface to be deposited in the deposited film formation target is a flat surface, the plurality of heating elements are arranged side by side on the same plane parallel or substantially parallel to the surface to be deposited, for example.

  In the case where the deposition surface in the deposited film formation target is a cylindrical surface, the plurality of heating elements are arranged side by side on, for example, concentric circles or substantially concentric circles surrounding the deposition surface.

  The plurality of heating elements are electrically connected in series, for example. The plurality of heating elements may be electrically connected in parallel.

  The hollow wire may be formed in a spiral shape or a meandering shape.

  The heating element may have a rectangular parallelepiped shape.

  The plurality of discharge ports may include first and second discharge port groups for discharging the deposited species in different directions.

  The heating element is preferably formed to have a melting point of 1600 ° C. or higher.

According to a second aspect of the present invention, there is provided a method for forming a deposited film on a deposited film forming object accommodated in a film forming chamber, wherein a raw material is formed in an internal space formed in a heating element that also serves as a gas supply head. A step of supplying a gas, a step of decomposing at least a part of the source gas supplied to the internal space by heat generated from the heating element to form a deposition species, and a step of decomposing the deposition species present in the internal space. And a step of discharging toward the deposition film forming object.

  The heating temperature of the heating element is, for example, 1600 ° C. or higher and 2300 ° C. or lower.

  In the third aspect of the present invention, the source gas is supplied into the space from one end side of the space surrounded by the annular heating surface, and at least a part of the supplied source gas is supplied to the heating surface. The deposited film is formed on the deposited film forming object by decomposing by the generated heat to be deposited seed and releasing the deposited seed from the other end side of the space toward the deposited film forming object. A method for forming a deposited film is provided.

  The heating temperature of the heating surface is, for example, 1600 ° C. or higher and 2300 ° C. or lower.

  According to the present invention, deposition species are generated by reactions such as decomposition, activation, and bonding of the source gas in the internal space of the heating element (the space surrounded by the heating surface). The deposited species generated in the internal space of the heating element is discharged toward the deposition film formation target through the discharge port. That is, the direction in which the deposited species proceeds outside the heating element (in the film formation chamber) can be defined by the discharge port. For this reason, by appropriately setting the arrangement of the heating elements or the shape and position of the discharge port according to the shape of the deposition surface of the deposition film formation target, the deposition species are emitted toward the portion other than the deposition surface. It is possible to prevent the deposited film from being formed unnecessarily. On the other hand, inside the heating element, since the heating element is heated, gas is decomposed by the heat radiation of the heating element, so that almost no deposition species are deposited on the heating element itself. Therefore, in the present invention, since the deposition film is suppressed from being formed on the surface other than the surface to be deposited, it is possible to prevent the unnecessary film from being peeled off and causing a film formation defect.

  In addition, if it is possible to suppress the formation of a deposited film on a surface other than the surface to be deposited, the frequency of cleaning using an etching gas or the like can be reduced, so that the film forming process efficiency can be improved and the manufacturing cost can be suppressed. Become.

  Furthermore, since the radiation direction of the deposited species can be regulated by the discharge port, the deposited species can be uniformly brought into contact with the surface to be deposited. As a result, it is possible not only to form a uniform film with small film thickness unevenness, but also to select a large area to be deposited by appropriately selecting the arrangement and shape of the heating element and the arrangement and shape of the discharge port. In contrast, it is possible to form a film with little film thickness unevenness.

  In the present invention, if a plurality of heating elements are electrically connected in series, the current value in each heating element becomes constant, so that the heat generation state in the plurality of heating elements is made uniform, and the plurality of heating elements are mutually connected. The radiation state of the deposited species can be made uniform. Therefore, if a plurality of heating elements are electrically connected in series, a uniform film can be formed on the deposited film formation target. On the other hand, if a plurality of heating elements are electrically connected in parallel, the potential difference in each heating element can be reduced even when a large number of heating elements are used. For this reason, when a deposited film is formed on a large area to be deposited, it is advantageous to connect a plurality of heating elements in parallel.

  In the present invention, if a plurality of discharge ports include the first and second discharge port groups for discharging the deposition species in different directions, a deposited film is simultaneously formed on a plurality of deposited film formation objects. Therefore, processing efficiency can be improved.

  In the present invention, if the heating element is formed so as to have a melting point of 1600 ° C. or higher, the heating element does not evaporate, the heating element is bent or distorted, or the shape of the discharge port changes. This can be suppressed. As a result, stable film formation can be repeated even when the heating element is used repeatedly.

  Hereinafter, a deposited film forming apparatus according to the present invention will be described with reference to the drawings.

  First, a deposited film forming apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

  A deposited film forming apparatus 1 shown in FIGS. 1 to 3 is for forming a deposited film on a flat substrate 3 in a deposition chamber 20 defined by a container 2. A gas supply means 5 and a plurality of heating elements 6 are provided.

The container 2 is partly formed to be openable and closable so that the flat substrate 3 can be taken in and out of the film forming chamber 20 and has a gas exhaust port 21. The gas exhaust port 21 is for exhausting the gas in the film forming chamber 20 to the outside, and is connected to a pump (for example, a mechanical booster pump or a rotary pump) not shown. The film forming chamber 20 is evacuated by exhausting gas from the film forming chamber 20 through the gas exhaust port 21 by a pump (not shown). The pressure in the film forming chamber 20 is, for example, 1.0 Pa or more and 100 Pa or less during film formation. Moreover, it is preferable that the film forming chamber 20 is previously set to a high vacuum of about 10 ⁻³ Pa before film formation. By doing so, moisture and residual impurity gas are sufficiently removed from the film formation chamber 20 before film formation, so that water and residual impurity gas remaining in the film formation chamber 20 are decomposed and deposited on the flat substrate 3. Can be sufficiently suppressed.

  The substrate support 4 is for holding the flat substrate 3, and a temperature adjusting means 40 is provided therein.

  The temperature adjusting means 40 is for maintaining the temperature of the flat substrate 3 at a target temperature, and has a heating / cooling mechanism and a temperature detection mechanism. As the heating mechanism, for example, an electrical device such as a nichrome wire, a sheathed heater and a cartridge heater, or a device using oil or the like as a heat medium is used. As the cooling mechanism, for example, a gas such as air and nitrogen gas, water or Oil or the like is used as a cooling medium. In the heating / cooling mechanism, it is preferable to configure the heat transfer medium that circulates and flows through the inside of the substrate support 4 with a liquid or gas as the heat transfer medium. As the temperature detection mechanism, a thermistor, a thermocouple, or the like is used.

  In such temperature adjusting means 40, the temperature of the substrate support 4 is monitored by the temperature detection mechanism, and the heating / cooling mechanism is controlled by the control means (not shown), thereby supporting the substrate before and during film formation. The temperature of the body 4 (flat substrate 3) is adjusted to the target temperature.

  Here, the temperature of the flat substrate 3 is determined by the composition of the deposited film to be formed on the surface of the flat substrate 3, the material of the flat substrate 3, and the like. For example, amorphous silicon (a-Si) -based deposition is performed. In the case of forming a film, the film is controlled to a substantially constant temperature of 100 ° C. to 400 ° C., preferably 200 ° C. to 350 ° C.

  The gas supply means 5 is for supplying a source gas to the film forming chamber 20 (inside the heating element 6), and includes a gas cylinder 50, a pressure reducing valve 51, and a mass flow controller 52.

The gas cylinder 50 is filled with a raw material gas to be supplied to the film forming chamber 20 (inside the heating element 6), and is connected to the heating element 6 through a pipe 53. Here, when an a-Si-based deposited film is formed on the surface of the flat substrate 3, a gas containing Si atoms, for example, SiH ₄ , Si ₂ H ₆ , Si ₃ H ₈ , SiF ₄ , SiCl ₄ , Alternatively, SiCl ₂ H ₂ or the like can be used.

  The pressure reducing valve 51 and the mass flow controller 52 are for adjusting the flow rate and gas pressure of each source gas component introduced into the film forming chamber 20.

  The plurality of heating elements 6 are for decomposing the raw material gas, and are configured to decompose the raw material gas by Joule heat generated when heat is generated by power supply from the power source 60. The plurality of heating elements 6 are formed as linear resistors by a hollow wire having an internal space 61 and a plurality of discharge ports 62.

  As a material for forming the heating element 6, the reaction product can be used as a deposition species and has a relatively high melting point (for example, a melting point of 1600 ° C. or more), and the heating element itself is deposited by sublimation or evaporation. Those that are difficult to be mixed in are used. Examples of such materials include tantalum (Ta), tungsten (W), platinum (Pt), palladium (Pd), molybdenum (Mo), titanium (Ti), niobium (Nb), cobalt (Co), nickel ( A material having at least one selected from the group consisting of Ni), chromium (Cr), manganese (Mn), and rhenium (Re) as a main component or an alloy component can be given. As a material for forming the heating element 6, conductive ceramics such as silicon carbide (SiC) can be used instead of metal or alloy material.

  The wire diameters of the heating elements 6 are such that each heating element 6 has an outer diameter D1 of 0.3 mm to 10.0 mm and an inner diameter of 0.1 mm to 9.0 mm. In this embodiment, the several heat generating body 6 is arrange | positioned on the same plane at equal intervals so that the axial direction may become mutually parallel. Adjacent ones of the plurality of heating elements 6 are connected by a conductor 63, and the heating element 6 located at the end is connected to a power source 60, and the plurality of heating elements 6 are electrically connected in series. It is made to become. When a plurality of heating elements 6 are connected in series, the current value in each heating element 6 becomes constant, so that the heat generation state in the plurality of heating elements 6 can be made uniform. As a result, when the plurality of heating elements 6 are connected in series, the radiation state of the deposited species in the plurality of heating elements 6 can be made uniform, so that a uniform film can be formed on the flat substrate 3. It becomes possible.

  As the power source 60, a DC power source is usually used, but an AC power source may be used. When an AC power supply is used, a matching circuit is separately provided as necessary. Each heating element 6 has a lower end fixed to the container 2 via an insulating member 64 and is sealed by the insulating member 64. On the other hand, the upper end of the heating element 6 is fixed to the container 2 via a pipe 65 formed of an insulating material such as a ceramic pipe.

  Here, the distance L1 between each heating element 6 and the flat substrate 3 is for efficiently transporting the deposition species (decomposition component) generated by the decomposition of the source gas toward the flat substrate 3, or In order to prevent damage to the flat substrate 3 and the deposited film due to radiant heat from the heating element 6, it is set to, for example, 3 mm to 100 mm, preferably 5 mm to 50 mm, and more preferably 10 mm to 40 mm. . The distance L2 between the adjacent heating elements 6 is determined according to the size of the heating element 6, the size of the discharge port 62, the size of the flat substrate 3, etc., for example, 10 mm or more and 100 mm or less, 10 mm or more and 75 mm. Set to:

  The internal space 61 is a portion to which the source gas is supplied by the gas supply means 5. It communicates with the inside of the gas cylinder 50 via a pipe 53. In the internal space 61, the source gas is heated and decomposed by the heat generated from the heating surface that is the inner surface of the heating element 6.

  The plurality of discharge ports 62 are provided side by side in the axial direction so as to face the deposition surface 30 of the flat substrate 3. Each discharge port 62 communicates with the internal space 61 so that the deposition species generated when the source gas is decomposed in the internal space 61 can be discharged toward the flat substrate 3. The discharge port 62 is formed in a circular shape, and its diameter D is, for example, 0.1 mm or more and 1.0 mm or less, and the pitch P between the adjacent discharge ports 60 is, for example, 0.5 mm or more and 25. 0.0 mm or less.

  Of course, the configuration of the discharge port 62 can be variously changed, and various shapes such as a triangle, a square, a rectangle, a rhombus, and a hexagon can be adopted in addition to a circle.

  Next, the case where a thin film (deposited film) is formed on the deposition surface 30 of the flat substrate 3 shown in FIG. 3 using the heating element CVD apparatus 1 will be described.

  When a target film is formed on the flat substrate 3 using the heating element CVD apparatus 1, the flat substrate 3 is first set on the substrate support 4. The flat substrate 3 is set on the substrate support 4 with the deposition surface 30 facing the discharge port 62 of the heating element 6.

  When the flat substrate 3 is set on the substrate support 4, the gas in the film forming chamber 20 is exhausted from the gas exhaust port 21 using a vacuum pump and the film forming chamber 20 is kept in a vacuum state. The gas supply means 5 is used to supply the source gas to the internal space 61 of each heating element 6 while causing each heating element 6 to generate heat.

  The source gas is supplied to the internal space 61 of the heating element 6 with the flow rate and gas pressure adjusted by the pressure reducing valve 51 and the mass flow controller 52. On the other hand, the heat generation temperature of the heating element 6 is set in a range of, for example, 1600 ° C. or more and 2300 ° C. or less.

  In this way, the raw material gas is heated in the internal space 61 by the heat from the inner surface (heating surface) of the heating element 6 by heating the heating element 6 while supplying the raw material gas to the internal space 61 of the heating element 6. Disassembled. The decomposition component generated at this time is discharged from the internal space 61 to the outside through the discharge port 62. Since the discharge port 62 is arranged facing the flat substrate 3, the deposition species discharged from the discharge port 62 are deposited on the deposition surface 30 of the flat substrate 3, and the a-Si layer is formed. It is formed.

  According to the heating element CVD apparatus 1 described above, the deposition species generated in the internal space 61 of the heating element 6 are discharged toward the deposition surface 30 of the flat substrate 3 through the discharge port 62. The direction in which the deposited species proceeds outside the heating element 6 can be defined by the discharge port 62. Therefore, by appropriately setting the arrangement of the heating element 6 or the shape and position of the discharge port 62 in accordance with the shape of the deposition surface 30 of the flat substrate 3 and the like, the deposition species are placed on portions other than the deposition surface 30. Therefore, it is possible to suppress the formation of a deposited film unnecessarily.

  On the other hand, in the internal space 61 of the heating element 6, since the heating element 6 is heated, gas is decomposed by the heat radiation of the heating element 6, so that almost no deposition species are deposited on the heating element 6 itself. . Therefore, in the present invention, since the deposition film is suppressed from being formed on the surface other than the deposition target surface 30, it is possible to prevent the unnecessary film from peeling off and causing a film formation defect.

  Further, if it is possible to suppress the formation of a deposited film other than the deposition surface 30, the frequency of cleaning using an etching gas or the like can be reduced, so that the film forming process efficiency can be improved and the manufacturing cost can be suppressed. It becomes.

  Furthermore, since the emission direction of the deposited species can be regulated by the discharge port 62, the deposited species can be uniformly brought into contact with the deposition target surface 30. As a result, it is possible not only to form a uniform film with small film thickness unevenness, but also to appropriately deposit a large area by appropriately selecting the arrangement and shape of the heating element 6 and the arrangement and shape of the discharge port 62. A film with little film thickness unevenness can be formed on the surface 30 as well.

  The heating element CVD apparatus 1 in the present embodiment can be variously changed and improved without departing from the gist of the present invention. For example, the heating element CVD apparatus 1 according to the present invention may be configured as shown in FIGS.

  In the heating element CVD apparatus 1A shown in FIG. 4, a plurality of heating elements 6A are arranged such that their axial centers are oriented in the horizontal direction. The heating element CVD apparatus 1B shown in FIG. 5 is provided with slits 62B extending in the axial direction of the heating element 6B instead of the plurality of discharge ports 62 (see FIGS. 1 and 3) in each heating element 6. . A heating element CVD apparatus 1C shown in FIG. 6 has a plurality of heating elements 6C electrically arranged in parallel. If a plurality of heating elements are electrically connected in parallel, the potential difference in each heating element can be reduced even when a large number of heating elements are used. For this reason, when a deposited film is formed on a large area to be deposited, it is advantageous to connect a plurality of heating elements in parallel.

  Further, the heating method of the heating element is generally an electric means, but any method other than heating, for example, if the method can raise the temperature of the heating element to a temperature necessary to activate the source gas, for example, It is also possible to use a radiant heat source or direct heating by a combustor

  Next, a heating element CVD apparatus 7A according to a second embodiment of the present invention will be described with reference to FIG. However, the same elements as those of the heating element CVD apparatus 1 (see FIGS. 1 to 3) according to the first embodiment of the present invention described above are denoted by the same reference numerals, and the following description is not repeated. Omitted.

  The heating element CVD apparatus 7A shown in FIG. 7 is configured to form a deposited film on the flat substrate 3 by one heating element 70A. The heating element 70A has a form in which a cylindrical wire is processed into a spiral shape.

  The heating element 70 </ b> A is provided with a plurality of discharge ports 71 </ b> A at a portion facing the planar substrate 3. The plurality of discharge ports 71A are arranged in a matrix as a whole. Therefore, the deposited species can be brought into contact with the planar substrate 3 substantially uniformly over the entire surface to be deposited. Further, such a heating element 70A can be suitably used when a deposited film is formed on the deposition surface of the flat substrate 3 having a large area.

  Next, a heating element CVD apparatus 7B according to a third embodiment of the present invention will be described with reference to FIG.

  The heating element CVD apparatus 7B shown in FIG. 8 forms a deposited film on the flat substrate 3 by one heating element 70B, similarly to the heating element CVD apparatus 7A described above with reference to FIG. It is composed of. The heating element 70B has a form obtained by processing a cylindrical shape into a meandering shape.

  The heating element 70 </ b> B is provided with a plurality of discharge ports 71 </ b> B at a portion facing the planar substrate 3. The plurality of discharge ports 71B are arranged in a matrix as a whole. Therefore, the deposited species can be brought into contact with the planar substrate 3 substantially uniformly over the entire surface to be deposited. Further, such a heating element 70B can be suitably employed when a deposited film is formed on the deposition surface of the flat substrate 3 having a large area.

  Next, a heating element CVD apparatus 7C according to a fourth embodiment of the present invention will be described with reference to FIGS.

  The heating element CVD apparatus 7C shown in FIGS. 9 and 10 forms a deposited film on a flat substrate by one heating element 70C, similar to the heating element CVD apparatus 7A described above with reference to FIG. It is comprised so that it may do.

  The heating element 70C has a rectangular parallelepiped shape in appearance, and is formed in a hollow shape having an internal space 71C. A through-hole 73C is formed in the back wall 72C of the heating element 70C, and the front wall 74C of the heating element 70C configured to be able to introduce the source gas into the internal space 71C through the through-hole 73C A plurality of discharge ports 75C are provided in a slit shape. The plurality of discharge ports 75 </ b> C extend in the vertical direction so that the deposition species generated in the internal space 71 </ b> C can be discharged toward the flat substrate 3. A side wall 76C of the heating element 70C is surrounded by a conductor wire 77C. The conductor wire 77C is connected to a high frequency power supply 78C, and the heating element 70C is configured to generate heat when a high frequency is applied to the conductor wire 77C.

  Of course, the through hole 73C for introducing the source gas into the internal space 71C is not necessarily provided in the back wall 72C, and may be provided in the side wall 76C. The heating element 70C may be heated by a method other than high frequency application. Furthermore, as shown in FIG. 11, the discharge port 75 </ b> C of the heating element 70 </ b> C is not necessarily provided in a slit shape, and may be formed as a plurality of through holes arranged in a matrix shape.

  Next, a heating element CVD apparatus 7D according to a fifth embodiment of the present invention will be described with reference to FIG.

  The heating element CVD apparatus 7D shown in FIG. 12 is configured to simultaneously form deposited films on the two flat substrates 3A and 3B by a plurality of heating elements 70D. The heating element CVD apparatus 7D includes two substrate supports 71D and 72D so that the two flat plates 3A and 3B can be individually supported. These substrate supports 71D and 72D can support the two flat substrates 3A and 3B so that their deposition surfaces 30A and 30B face each other. A plurality of heating elements 70D (one in the drawing) are arranged between the two substrate supports 3A and 3B. Although not clearly understood from the drawing, the plurality of heating elements 70D are arranged side by side on the same plane parallel or substantially parallel to the deposition surfaces 30A and 30B. Each heating element 70D is formed as a cylindrical wire having an internal space 73D, and has a plurality of discharge ports 74D and 75D communicating with the internal space 73D. The plurality of discharge ports 74D and 75D are configured to be able to discharge the deposited species in different directions. The plurality of discharge ports 74D face the deposition surface 30A of the flat substrate 3A, and the plurality of discharge ports 75D. It faces the deposition surface 30B of the flat substrate 3B.

  In the heating element CVD device 7D, the source gas supplied to the internal space 73D of the heating element 70D is used as a deposition species in the internal space 73D by the heating element 70D. This deposited species is discharged through a plurality of discharge ports 74D and 75D. The plurality of discharge ports 74D and 75D include a first discharge port 74D that faces the deposition surface 30A of the flat substrate 3A and a second discharge port 75D that faces the deposition surface 30B of the flat substrate 3B. Therefore, the deposition species are brought into contact with the deposition surfaces 30A and 30B of the two flat substrates 3A and 3B, respectively. As a result, the heating element CVD apparatus 7D can simultaneously form deposited films on the two flat substrates 3A and 3B.

  Next, a heating element CVD apparatus 1 ′ according to a sixth embodiment of the present invention will be described with reference to FIGS.

  A heating element CVD apparatus 1 'shown in FIGS. 13 and 14 is for forming a deposited film on a cylindrical substrate 80 in a film forming chamber 20' defined by a container 2 '. 4 ', rotation means 8', gas supply means 5 ', and heating element 6'.

  The container 2 ′ is similar to the container 2 of the heating element CVD apparatus 1 described with reference to FIGS. 1 to 3 in that it has a gas exhaust port 21 ′ connected to a pump (not shown). It is different in that it is formed in a cylindrical shape.

  The substrate support 4 ′ is for holding the cylindrical substrate 80, and is rotatably supported with respect to the container 2 ′ by the rotating means 8 ′. The cylindrical base body 80 is held by the base body support body 4 ′ with the base body support body 4 ′ inserted therein. Each substrate support 4 'is formed in a hollow cylindrical shape, and temperature adjusting means (not shown) is provided therein. The temperature adjusting means maintains the temperature of the cylindrical base body 80 at a target temperature, and has a heating / cooling mechanism and a temperature detection mechanism. In such temperature adjusting means, the temperature of the substrate support 4 ′ is monitored by the temperature detection mechanism, and the heating / cooling mechanism is controlled by the control means (not shown), thereby supporting the substrate before and during film formation. The temperature of the body 4 '(cylindrical base body 80) is adjusted to the target temperature.

  Here, the temperature of the cylindrical substrate 80 is determined by the composition of the deposited film to be formed on the surface of the cylindrical substrate 80, the material of the cylindrical substrate 80, and the like. For example, a-Si-based or amorphous silicon carbide ( When an a-SiC) -based deposited film is formed, the film is controlled to a substantially constant temperature of 100 ° C. to 400 ° C., preferably 200 ° C. to 350 ° C.

  The rotating means 8 'is for rotating each substrate support 4', and is configured so that it can be connected and disconnected in a vacuum. As such a connection mechanism, a combination of a current connection terminal and a solenoid or a combination of a slip ring and a brush is used for electrical wiring, and a combination of a quick coupling and a solenoid is used for a medium. For transmission of rotational power, a combination of gears or a combination of gears and solenoids is used. A rotating mechanism capable of maintaining the vacuum of the film forming chamber 20 'is provided at the contact point between the rotating means 8' and the container 2 '. As such a rotation mechanism, vacuum seal means such as an oil seal or a mechanical seal having a double or triple rotation shaft can be used. When the temperature of the cylindrical base body 80 is controlled to detect the temperature of the cylindrical base body 80, the rotary shaft is formed hollow, and the temperature detection mechanism and its wiring are provided inside the rotary shaft. Can also be provided.

  When the substrate support 4 'is rotated by such a rotating means 8', the cylindrical substrate 80 held by the substrate support 4 'can be rotated, so that it is disassembled by the heating element 6'. The decomposition component of the source gas can be deposited to a substantially uniform film thickness over the entire surface of the cylindrical substrate 80. The rotation speed of the substrate support 4 ′ by the rotating means 8 ′ is, for example, 1 to 10 rpm.

  The gas supply means 5 'is for supplying a source gas to the film forming chamber 20', and includes a plurality (four in the drawing) of gas cylinders 51A ', 51B', 51C ', 51D'. Yes.

  The plurality of gas cylinders 51A ′, 51B ′, 51C ′, 51D ′ are filled with the raw material gas to be supplied to the film forming chamber 20 ′, and the pipes 52A ′, 52B ′, 52C ′, 52D ′, 53 ′ are filled. To the film forming chamber 20 '. Here, FIG. 13 shows an example of gas cylinders 51 </ b> A ′ to 51 </ b> D ′ in the case where a-Si-based and a-SiC-based deposited films are formed on the surface of the cylindrical substrate 80. That is, each of the gas cylinders 51A ′ to 51′D is filled with Si source gas, C source gas, valence electron control source gas, or dilution gas. In the middle of the pipes 52A 'to 52D', 53 ', pressure reducing valves 54A', 54B ', 54C', 54D 'and mass flow controllers 55A', 55B ', 55C', 55D 'are provided. It is possible to adjust the flow rate, gas pressure, and composition of each source gas component introduced into the membrane chamber 20 '.

Examples of the Si source gas include compounds composed of Si and H, such as SiH ₄ , Si ₂ H ₆ , and Si ₃ H ₈ , and compounds composed of silicon and a halogen element, such as SiF ₄ , SiCl ₄ , or SiCl ₂ H. ₂ or the like can be used.

As the C source gas, for example, a compound containing C such as CH ₄ , C ₂ H ₂ , C ₃ H ₈ , CO, or CO ₂ is used.

As a valence electron control gas (a gas for controlling the number of valence electrons in the film), a P-type impurity or an N-type impurity can be used. Examples of P-type impurities include compounds containing Group 13 elements (B, Al, Ga, etc.), such as B ₂ H ₆ , B (CH ₃ ) ₃ , Al (CH ₃ ) ₃ , Al (C ₂ H ₅ ) ₃ , Ga (CH ₃ ) _3, or the like can be used. On the other hand, as the N-type impurity, a compound containing an element belonging to Group 15 of the periodic table (P, As, Sb, etc.), for example, PH ₃ , P ₂ H ₄ , AsH ₃ , SbH _3, etc. can be used.

The diluent gas can be used, for example _{H 2, N 2, He,} Ar, Ne, and Xe.

Moreover, you may use the band gap adjustment gas as needed. As the band gap adjusting gas, when increasing the band gap, a compound containing C, N, O, for example, CH ₄ , C ₂ H ₂ , C ₃ H ₈ , N ₂ , NH ₃ , NO, N ₂ O, NO ₂ , O ₂ , CO, and CO ₂ can be used. When the band gap is reduced, for example, a compound containing Ge or Sn, for example, GeH ₄ , SnH ₄ , Sn (CH ₃ ) ₃ is used. Can be used.

  The heating element 6 ′ is for decomposing the source gas by Joule heat generated by heating, and has the same configuration as the heating element 6 of the heating element CVD apparatus 1 described with reference to FIGS. 1 to 3. Yes. That is, the heating element 6 ′ is formed as a hollow wire having an internal space 61 ′ and a plurality of discharge ports 62 ′.

  The distance between the heating element 6 ′ and the cylindrical substrate 80 is such that the deposition species (decomposition component) generated by the decomposition of the raw material gas is efficiently transported toward the cylindrical substrate 80, or from the heating element 6 ′. In order to prevent damage to the cylindrical substrate 80 and the deposited film due to the radiant heat of, for example, 3 mm to 100 mm, preferably 5 mm to 50 mm, more preferably 10 mm to 40 mm.

  Next, the case where the electrophotographic photosensitive member 8 shown in FIG. 15 is produced using the heating element CVD apparatus 1 will be described as an example. In the electrophotographic photoreceptor 8 shown in FIG. 15, a carrier injection blocking layer 81, a photoconductive layer 82, and a surface protective layer 83 are sequentially laminated on the surface of a cylindrical substrate 80.

  When a target film is formed on the cylindrical substrate 80 using the heating element CVD apparatus 1, the cylindrical substrate 80 is first set on the substrate support 4 '.

  As the cylindrical substrate 80, a conductive or insulating material is used, or a material in which a conductive layer is formed on the surface of the insulating substrate.

  Examples of the conductive substrate include aluminum (Al), stainless steel (SUS), iron (Fe), nickel (Ni), chromium (Cr), manganese (Mn), copper (Cu), and titanium (Ti). The thing formed with the metal or these alloys can be mentioned.

  Examples of the insulating substrate include inorganic insulators such as glass (borosilicate glass and soda glass), ceramics, quartz, and sapphire, or fluororesin, polycarbonate, polyethylene terephthalate, polyester, polyethylene, polypropylene, polystyrene, polyamide, and vinylon. And synthetic resin insulators such as epoxy and mylar.

  As the conductive layer formed on the insulating base, for example, on the surface of the insulating base, a conductive layer such as ITO (indium / tin / oxide), tin oxide, lead oxide, indium oxide, and copper iodide, Al Metal layers such as Ni, Au, and gold (Au) can be employed. The conductive layer may be, for example, a vacuum deposition method, an active reaction deposition method, an ion plating method, an RF sputtering method, a DC sputtering method, an RF magnetron sputtering method, a DC magnetron sputtering method, a thermal CVD method, a plasma CVD method, a spray method, It can be formed by a coating method or a dipping method.

  When the cylindrical substrate 80 is supported on the substrate support 4 ′, the carrier injection blocking layer 81 and the photoconductive layer 82 are formed as an a-Si layer on the cylindrical substrate 80. In this step, the gas in the film forming chamber 20 ′ is exhausted from the gas exhaust port 21 ′ using a vacuum pump and the film forming chamber 20 ′ is kept in a vacuum state, and the source gas is used using the gas supply means 5 ′. Is supplied to the film forming chamber 20 'while the heating element 6' generates heat.

When the carrier injection blocking layer 81 and the photoconductive layer 82 are formed as the a-Si layer, as a raw material gas, for example, a mixed gas in which SiH ₄ as a Si source gas and H ₂ as a dilution gas are mixed in a desired ratio. Is used. Further, the mixing ratio of SiH ₄ and H ₂ is adjusted using the pressure reducing valves 53A ′ to 53D ′ and the mass flow controllers 54A ′ to 54D ′. The mixed gas is mixed with a valence electron control gas, a band gap adjusting gas, or the like as necessary. On the other hand, the heat generation temperature of the heat generating element 6 'is set, for example, in the range of 1600 ° C to 1800 ° C.

  In this way, the heating element 6 'generates heat while supplying the source gas to the film forming chamber 20', so that the source gas is brought into contact with the heating element 6 'and heated and decomposed. Decomposition components generated at this time are deposited on the surface of the cylindrical substrate 80 to form an a-Si layer. Then, by appropriately changing the composition of the source gas, the carrier injection blocking layer 81 and the a-Si layer as the photoconductive layer 82 are sequentially formed on the surface of the cylindrical substrate 80.

  When an a-Si layer is formed on the surface of the cylindrical substrate 80 using the carrier injection blocking layer 81 and the photoconductive layer 82, the surface protective layer 83 is then formed as an a-SiC layer. In this step, the supply of the source gas and the like is first interrupted, and preparations for supplying the source gas to the film forming chamber 20 'are made. Next, the gas in the film forming chamber 20 ′ is exhausted from the gas exhaust port 21 ′ by using a vacuum pump to maintain the vacuum state of the film forming chamber 20 ′. While supplying to the film chamber 20 ', the heating element 6' generates heat.

As a raw material gas in the case of forming the surface protective layer 83 as an a-SiC layer, for example, a mixed gas in which SiH ₄ as a Si source, C ₂ H ₂ as a C source, and H ₂ as a diluent gas are mixed in a desired ratio. Used. In addition, the mixing ratio of SiH ₄ , C ₂ H ₂ and H ₂ is adjusted using the pressure reducing valves 53A ′ to 53D ′ and the mass flow controllers 54A ′ to 54D ′. A valence electron control gas, a band gap adjusting gas, or the like is mixed. The heating temperature of the heating element 6 'is set in the range of 1800 ° C or higher and 2300 ° C or lower, for example.

  In this way, the heating element 6 'generates heat while supplying the source gas to the film forming chamber 20', so that the source gas is brought into contact with the heating element 6 'and heated and decomposed. The decomposition component generated at this time is deposited on the surface of the cylindrical substrate 80, and an a-Si layer as the surface protective layer 33 is formed on the surface of the cylindrical substrate 80.

  According to the heating element CVD apparatus 1 ′ described above, the deposition species generated by the source gas in the internal space 61 ′ of the heating element 6 ′ are controlled in the emission direction by the emission port 62 ′, while the emission port 62 ′. It discharges | emits toward the cylindrical base | substrate 80 through '. Therefore, even when a deposited film is formed on the cylindrical substrate 80 as in the case of manufacturing the electrophotographic photosensitive member 8, the deposited species are emitted toward portions other than the surface of the cylindrical substrate 8. It is possible to prevent the deposition film from being formed unnecessarily on the surface of the cylindrical substrate 8, and to prevent the deposition film from being formed on the heating element 6 'itself. be able to. As a result, it is possible to suppress the occurrence of film formation defects due to separation of unnecessary films, and it is possible to reduce the frequency of cleaning the inside of the heating element 6 ′ and the film formation chamber 20 using an etching gas or the like. Thus, the film forming process efficiency is improved, and the manufacturing cost can be suppressed.

  In this embodiment, when a film is repeatedly formed on the flat substrate 3 using the heating element CVD apparatus 1 shown in FIGS. The state was examined.

  As the flat substrate 3, a glass plate having a size of 150 mm × 150 mm × 1 mm was used. A silicon film having a film thickness of 5 μm was formed on the flat substrate 3 at a film forming rate of 5 μm / hour under the following conditions. Such a silicon film was continuously formed on ten glass plates.

  The film formation defect was performed by visually counting the number of pinholes having a diameter of 0.1 mm or more generated on the silicon film. The number of pinholes generated is shown in Table 2 below.

  On the other hand, as a comparative example, the number of pinholes generated when a silicon film was formed on a glass plate was examined in the same manner as in the present case using the conventional heating element CVD apparatus 9 shown in FIG. The results are shown in Table 2 below together with the results of this proposal.

  As can be seen from Table 2, in the comparative example, when the silicon film is formed on the third glass plate, the number of pinholes starts to increase rapidly, and when the silicon film is formed on the tenth glass plate. About 20 times as many pinholes as when the silicon film was formed on the first glass plate were counted. In the comparative example, it is considered that a deposited film or powder was formed on the surface of the shower plate 96, and it dropped on the glass plate to generate many pinholes.

  On the other hand, in this example (this plan), even when the silicon film is formed on the tenth glass plate, the number of pinholes is twice that when the silicon film is formed on the first glass plate. Is within. As described above, in this embodiment, the occurrence of film formation defects is appropriately suppressed even by repeated film formation processing. Therefore, according to the present embodiment, since the frequency of cleaning can be reduced, the film forming process efficiency can be improved and the manufacturing cost can be suppressed.

It is a longitudinal cross-sectional view which shows the heat generating body CVD apparatus which concerns on the 1st Embodiment of this invention. It is sectional drawing which follows the II-II line of FIG. It is sectional drawing which follows the III-III line of FIG. It is sectional drawing equivalent to FIG. 3 which shows the heat generating body CVD apparatus which concerns on the 2nd Embodiment of this invention. It is sectional drawing equivalent to FIG. 3 which shows the heat generating body CVD apparatus which concerns on the 3rd Embodiment of this invention. It is sectional drawing equivalent to FIG. 3 which shows the heat generating body CVD apparatus which concerns on the 4th Embodiment of this invention. It is sectional drawing equivalent to FIG. 3 which shows the heat generating body CVD apparatus which concerns on the 5th Embodiment of this invention. It is sectional drawing equivalent to FIG. 3 which shows the heat generating body CVD apparatus which concerns on the 6th Embodiment of this invention. It is a perspective view which shows the surroundings of the heat generating body for demonstrating the heat generating CVD apparatus which concerns on the 7th Embodiment of this invention. It is sectional drawing which follows the XX line of FIG. It is a front view which shows the circumference | surroundings of the heat generating body for demonstrating the heat generating CVD apparatus which concerns on the 8th Embodiment of this invention. It is sectional drawing equivalent to FIG. 1 which shows the heat generating body CVD apparatus which concerns on the 9th Embodiment of this invention. It is sectional drawing equivalent to FIG. 1 which shows the heat generating body CVD apparatus which concerns on the 10th Embodiment of this invention. It is sectional drawing which follows the XIV-XIV line | wire of FIG. FIG. 14 is a cross-sectional view of an electrophotographic photosensitive member manufactured by the heating element CVD apparatus shown in FIG. 13 and an enlarged view of a main part thereof. It is a longitudinal cross-sectional view for demonstrating the conventional heat generating body CVD apparatus. It is sectional drawing which follows the XVII-XVII line of FIG.

Explanation of symbols

1,1 ', 1A, 1B, 1C, 7A, 7B, 7C, 7D heating element CVD apparatus 20, 20' film formation chamber 3, 3A, 3B flat substrate 30, 30A, 30B (plate substrate) deposition Surface 5, 5 'Gas supply means 80 Cylindrical substrate 6, 6', 6A, 6B, 6C, 6D, 6E, 70A, 70B, 70C, 70D Heating element 61 (of heating element) Internal space 62, 62 ', 62B , 71A, 71B, 75C, 75D (heating element) outlet

Claims (14)

A film formation chamber for accommodating a deposited film formation target;
Source gas supply means for supplying source gas to the film forming chamber;
One or more heating elements for using the source gas as a deposition species;
A gas supply head for releasing the source gas and the deposited species toward the deposited film formation target;
A deposited film forming apparatus comprising:
The heating element has an internal space through which the source gas supplied by the source gas supply means passes, and at least a part of the source gas passing therethrough is decomposed to become a deposition species, and the deposition existing in the internal space A deposited film forming apparatus comprising one or a plurality of discharge ports for discharging seeds toward the deposited film forming target and also serving as the gas supply head.   The deposited film forming apparatus according to claim 1, wherein the heating element is formed in a cylindrical shape.   The deposited film forming apparatus according to claim 2, wherein the heating element is a hollow wire. The hollow wire has a filament shape,
The deposited film forming apparatus according to claim 3, wherein the plurality of heating elements are arranged side by side so that their axial centers are parallel or substantially parallel to each other. In the case where the deposition surface in the deposited film formation object is a plane,
The deposited film forming apparatus according to claim 4, wherein the plurality of heating elements are arranged side by side on the same plane parallel to or substantially parallel to the deposition target surface. In the case where the surface to be deposited in the deposited film forming object is a cylindrical surface,
The deposition forming apparatus according to claim 4, wherein the plurality of heating elements are arranged side by side on a concentric circle or a substantially concentric circle surrounding the deposition surface.   The deposited film forming apparatus according to claim 4, wherein the plurality of heating elements are electrically connected in series.   The deposited film forming apparatus according to claim 4, wherein the plurality of heating elements are electrically connected in parallel.   The deposited film forming apparatus according to claim 3, wherein the hollow wire is formed in a spiral shape or a meandering shape.   The deposited film forming apparatus according to claim 1, wherein the heat generating body has a rectangular parallelepiped shape.   11. The deposited film formation according to claim 1, wherein the plurality of discharge ports include first and second discharge port groups for discharging the deposition species in different directions. apparatus.   The deposited film forming apparatus according to claim 1, wherein the heating element has a melting point of 1600 ° C. or higher. A method of forming a deposited film on a deposited film formation target housed in a film forming chamber,
Supplying a raw material gas to an internal space formed in a heating body that also serves as a gas supply head;
A step of decomposing at least a part of the source gas supplied to the internal space with the heat generated from the heating element to form a deposition species;
And a step of releasing the deposition species existing in the internal space toward the deposition film formation target.   The method for forming a deposited film according to claim 13, wherein the heating temperature of the heating element is 1600 ° C. or higher and 2300 ° C. or lower.

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