DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0091] In a process of heating a filament and thermally decomposing a reaction gas, powder and the like by thermal energy to deposit a film, in accordance with a process of forming a deposited film, processing process or conditions, and a filament material, an optimum filament heating temperature needs to be selected. When as the filament (high-melting metal filament) material a high-melting metal containing as a main component at least one of tungsten, molybdenum and rhenium or an alloy thereof is used, under forming conditions or processing conditions such that a relatively small amount of a by-product is generated, an effect is exhibited from a filament temperature of about 500° C., so that a non-reacted gas and a by-product are efficiently decomposed and can be deposited as a hard film on a trap wall surface. Furthermore, under more drastic forming conditions with a higher deposition rate of the deposited film, when the temperature of the high-melting metal filament is set to a higher temperature of 1400° C. or more, the non-reacted gas and by-product are efficiently decomposed and can be deposited as the hard film on the trap wall surface. Furthermore, by performing heating to the melting point of the simple substance of a substance of the reaction gas or a higher temperature, the powder of the by-product can also be decomposed, a high deposition rate can easily be obtained in a trap, and the non-reacted gas and by-product can efficiently be decomposed and deposited as the hard film on the trap wall surface.

[0092] In the present invention, power is supplied to the high-melting metal filament to be heated. The filament is formed of the high-melting metal. Therefore, when the processing process by a substrate processing apparatus or a film processing apparatus is continued for several hours to several dozens of hours, operation needs to be performed at a melting point of each material used in the filament or a lower temperature so that the material of the filament is prevented from being evaporated by the heating of the filament. Specifically, the melting point of tungsten is 3410° C., the melting point of molybdenum is 2620° C., and the melting point of rhenium is 3180° C.

[0093] In the present invention the heating temperature of the high-melting metal filament depends on the material thereof and the type and flow rate of the non-reacted gas, but to use the filament stably for a long time, control is preferably performed at a temperature lower than the melting point by 100° C. or more. The heating temperature of the high-melting metal filament is preferably in the range of 500° C. to 2200° C., more preferably 1400° C. to 2200° C. If the filament temperature is excessively low, the decomposition rate of non-reacted gas and by-product is lowered. Moreover, if the filament temperature is excessively high, there is a possibility that a vacuum seal of the apparatus is influenced. Therefore, it is preferable to select an optimum temperature in accordance with the processing conditions.

[0094] In the present invention, the configuration of the high-melting metal filament preferably comprises a single or a plurality of linear shapes, or linear shapes wound in spirals. The degree of freedom in a place where the apparatus can be installed can be raised in accordance with the configuration for use. For example, when the filament of the single linear shape is used, the trap can easily be installed even in a narrow exhaust path. Moreover, when a contact area of the non-reacted gas and the by-product is to be enlarged, the linear shape wound in the spiral is used, or a plurality of linear shapes or the liner forms wound in spirals are preferably arranged in the direction of an exhaust flow.

[0095] For example, when silane (SiH ₄ ), disilane (Si ₂ H ₆ ) or another amorphous silicon forming source gas is used as a film forming source gas, in the conventional process, the by-product sticking to an exhaust piping needs to be periodically removed, but the operation of removing the by-product after film formation requires a large number of processes and much time. In the present invention, since the powder of the by-product is decomposed and deposited as a stable film, it can safely and easily be removed.

[0096] In the present invention, to remove the film deposited on an inner wall of the trap, after the deposited film formation or another substrate processing or the film processing is completed, nitrogen (N ₂ ), helium (He) or another inert gas is flown to purge the source gas. After the gas is leaked to an atmospheric pressure, the trap inner wall is taken out to remove the film by a physical process (honing or the like) or a chemical process (etching or the like). In this case, when the trap wall is of a double structure, and only the inner wall is detachably provided, the inner wall can easily be removed. Moreover, when the inner wall surface is formed of a metal, the deposited film can easily be removed, and time required for maintenance can be shortened. As the metal material, stainless steel, aluminum or another metal, or an alloy containing any one of the metals can preferably be used.

[0097] Examples of the source gas for use in a deposited film forming apparatus as an embodiment of the substrate processing apparatus include silane (SiH ₄ ), disilane (Si ₂ H ₆ ) and another amorphous silicon forming source gas, germane (GeH ₄ ) and another source gas, and a mixture gas thereof.

[0098] Moreover, examples of a diluting gas of the source gas include H ₂ , Ar, He and the like.

[0099] Furthermore, for the purpose of doping, diborane (B ₂ H ₆ ), boron fluoride (BF ₃ ), phosphine (PH ₃ ) or another dopant gas may simultaneously be introduced into a discharge space (film forming space).

[0100] Additionally, examples of an etching gas for use in an etching apparatus as an embodiment of the film processing apparatus of the present invention include CF ₄ O ₂ , CH _x F _(4-x) , SiH _x F _(4-x) , SiH _x Cl _(4-x) , CH _x Cl _(4-x) (in which x=0, 1, 2, 3, or 4), ClF ₃ , NF ₃ , BrF ₃ , IF ₃ and another etching gas and a mixture gas thereof.

[0101] As a base (substrate) material, for example, stainless steel, Al, Cr, Mo, Au, In, Nb, Te, V, Ti, Pt, Pd, Fe or another metal, alloy thereof, polycarbonate or another synthetic resin having a conductivized surface, glass, ceramic, paper or the like is used.

[0102] In the apparatus of the present invention, during the processing, the substrate temperature is not especially limited, preferably not lower than 20° C. but no higher than 500° C., more preferably in the range of 50° C. to 450° C.

[0103] A specific embodiment of the apparatus will next be described with reference to the drawings.

[0104] FIG. 1 is a schematic sectional view of an embodiment of a plasma CVD apparatus as one deposited film forming apparatus of the present invention. In the drawing, reference numerals 1 to 20 denote the same members as those of the above-mentioned apparatus of FIG. 2 , and description thereof is omitted. Moreover, numeral 21 denotes a trap of the present invention, 22 denotes a high-melting metal filament, 23 denotes a filament power supply, and 24 denotes a controller.

[0105] In the embodiment, a non-reacted gas and a CVD by-product generated while the deposited film is formed are removed as follows:

[0106] First in the same manner as the procedure described for the apparatus of FIG. 2 , the deposited film is formed on the substrate 12 by plasma CVD in the deposited film forming chamber 1 . Before plasma is generated in the deposited film forming chamber 1 , power is supplied to the high-melting metal filament 22 having a circular arc shape from the filament power supply 23 via the controller 24 , so that heating is performed to a desired temperature. Since air is exhausted from the deposited film forming chamber 1 to a desired pressure by the exhaust piping 3 and the exhaust pump 2 , the non-reacted gas and by-product in the deposited film forming chamber 1 reach the trap 21 disposed in the exhaust path, decomposed by thermal energy of the high-melting metal filament 22 , and deposited as a hard film on an inner wall of the trap 21 . FIG. 3 is a partially cut perspective view showing another embodiment of the high-melting metal filament, in which the filament of a linear shape is formed into a spiral form. Moreover, FIG. 4 is a partially cut exploded perspective view showing another embodiment of the trap, in which a wall surface is of a double structure and an inner wall is detachably provided. Reference numeral 47 denotes a metal plate, which forms inner wall surfaces.

[0107] While the deposited film is formed using the apparatus of the embodiment of FIG. 1 , the non-reacted gas and by-product are decomposed and deposited as the hard film on the inner wall of the trap. Results are shown in Table 1.

[0108] FIG. 5 shows another embodiment of the present invention. In the embodiment, the present invention is applied to a deposited film forming apparatus using a roll to roll system where film forming chambers are arranged via gas gates. In the roll to roll system, a longitudinal belt-like substrate is used. While the substrate is continuously fed and supplied to a plurality of deposited film forming chambers, the deposited film is successively stacked and wound up.

[0109] Each member of the apparatus of FIG. 5 will be described. Between a feed chamber 25 for continuously feeding a belt-like substrate 35 wound on a bobbin 34 therein and a wind-up chamber 26 for winding the belt-like substrate 35 with the deposited film formed thereon onto a bobbin 36 , a plurality of deposited film forming chambers 27 to 31 are arranged along a straight line. Adjacent chambers are connected via gas gates 32 a to 32 f . Each of the chambers 27 to 31 is provided with a discharge power supply mechanism and a source gas supply mechanism, which are not shown. A gate gas is introduced to the gas gates 32 a to 32 f from gate gas introducing means 33 a to 33 f , so that interdiffusion between the adjacent deposited film forming chambers is prevented to maintain independence of the deposited film forming conditions. Moreover, each of the chambers 25 to 31 has an independent exhaust mechanism. Conductance adjusting valves 5 a to 5 g provided in exhaust pipings 3 a to 3 g function to control the pressure of each deposited film forming chamber. By adjusting the conductance adjusting valves 5 a to 5 g , the pressure of each deposited film forming chamber can independently be controlled.

[0110] In the embodiment, traps 21 a to 21 e are arranged in the exhaust pipings 3 a to 3 e between the chambers 27 to 31 and exhaust pumps 2 a to 2 e . Inside the traps, high-melting metal filaments 22 a to 22 e are provided in circular arc forms. The high-melting metal filaments 22 a to 22 e are connected to power supplies 23 a to 23 e via controllers 24 a to 24 e , and supplied with power. Reference numerals 4 a to 4 g are valves.

[0111] A deposited film forming procedure will be described by illustrating a case in which an nip type amorphous semiconductor layer of a photovoltaic element.

[0112] The longitudinal belt-like substrate 35 of stainless steel on which a back surface light reflecting layer is formed beforehand and which is wound around the bobbin is mounted in the feed chamber 25 . The belt-like substrate 35 is passed through the deposited film forming chambers 27 to 31 and the gas gates 32 a to 32 f from the feed chamber 25 , fixed to the bobbin 36 of the wind-up chamber 26 , and extended with a tension.

[0113] Subsequently, air is exhausted from each chamber by the exhaust means provided on each chamber to reduce the pressure to the order of 10 ⁻³ Torr. The deposited film forming chambers 27 to 31 are once placed in inert gas atmosphere, and discharge furnaces of the chambers 27 to 31 are heated to the deposited film forming conditions. After the furnaces are sufficiently heated, in order to maintain the independence of the deposited film forming conditions of the deposited film forming chambers 27 to 31 , hydrogen gas as a gate gas is introduced to the gas gates 32 a to 32 f via the gate gas introducing means 33 a to 33 f . A deposited film forming source gas is introduced to the deposited film forming chambers 27 to 31 by gas supply means.

[0114] While the pressure in the chambers 27 to 31 is controlled to be constant by the conductance adjusting valves 5 a to 5 e , an RF power or a microwave power is supplied to discharge regions in the deposited film forming chambers 27 to 31 . The discharge is caused and maintained, and the deposited film forming source gas is decomposed to form a deposited film on the belt-like substrate 35 which is continuously moved/supplied.

[0115] On the belt-like substrate 35 continuously supplied from the feed chamber 25 at a constant speed and moved through the deposited film forming chambers 27 to 31 , different deposited films are formed in succession. Specifically, an n-type semiconductor layer, i-type semiconductor (buffer) layer, i-type semiconductor layer, i-type semiconductor (buffer) layer, and p-type semiconductor layer are stacked and formed. Finally, the substrate is wound onto the bobbin 36 of the wind-up chamber 26 . After the deposited films are completely formed on the belt-like substrate 35 , an inert gas is passed through the chambers 25 to 31 , exhaust pipings 3 a to 3 g and exhaust pumps 2 a to 2 g to sufficiently purge residual source gas, so that the chambers 25 to 31 are returned to the atmospheric pressure. The belt-like substrate 35 removed from the wind-up chamber 26 is further subjected to an upper electrode and module formation process to be formed into the photovoltaic element.

[0116] The removal of the non-reacted gas and/or the by-product generated during the deposited film formation is performed by the traps 21 a to 21 e attached to the chambers 27 to 31 . The procedure is the same as in the apparatus of FIG. 1 . Before starting the discharge in the discharge regions of the deposited film forming chambers 27 to 31 , the power is supplied to heat the high-melting metal filaments 22 a to 22 e inside the traps 21 a to 21 e . Since air is exhausted from the deposited film forming chambers 27 to 31 by the exhaust pipings 3 a to 3 e and exhaust pumps 2 a to 2 e to provide a desired pressure, the non-reacted gas and CVD by-product in the deposited film forming chambers 27 to 31 reach the traps 21 a to 21 e provided in the exhaust path, are decomposed by the thermal energy of each high-melting metal filament, and deposited as hard films on inner walls of the traps 21 a to 21 e.

[0117] FIG. 6 shows a further embodiment of the present invention. FIG. 6 is a schematic partial sectional view of a high-frequency plasma CVD apparatus.

[0118] The embodiment is different in the above embodiment of FIG. 5 , in that the trap is disposed between a deposited film forming space and the exhaust piping inside each deposited film forming chamber.

[0119] In the apparatus of FIG. 6, a deposited film forming space 37 is provided in the deposited film forming chamber 27 . By supplying a high-frequency power between the electrically grounded belt-like substrate 35 and the cathode electrode 7 from a high-frequency power supply (not shown), plasma is formed in the deposited film forming space 37 to form a deposited film on a lower face (surface) of the belt-like substrate 35 . The deposited film forming space 37 is provided with a source gas introducing section 18 connected to a source gas supply system (not shown) and the exhaust piping 3 connected to an exhaust apparatus (not shown) to form a gas flow in parallel with the direction in which the belt-like substrate 35 moves.

[0120] In a flow path of source gas, a block heater 38 is provided for preheating the source gas before plasma decomposition and heating the deposited film forming space 37 to promote the decomposition of the source gas in the vicinity of a venting section and to reduce the amount of CVD by-products sticking to an inner wall of the deposited film forming space 37 . In an exhaust gas path, a deposited film forming space outer exhaust vent 39 is provided for exhausting outer gas (gate gas flowing from the gas gate 32 via a gate gas introducing means 33 , gas discharged from the inner wall of the deposited film forming chamber 27 and the like) of the deposited film forming space 37 to the exhaust piping 3 without passing the gas through the deposited film forming space 37 , so that impurities are prevented from being included into the deposited film.

[0121] Moreover, above the deposited film forming space 37 , in an inlet and outlet and at opposite ends in a width direction of the belt-like substrate 35 , plasma leak guards 48 are disposed for inhibiting the plasma in the deposited film forming chamber 27 from leaking to the outside.

[0122] On an upper face (back surface) of the belt-like substrate 35 in the deposited film forming chamber 27 , lamp heaters 41 , 42 are fixed to an openable/closable lid 40 of the deposited film forming chamber 27 , so that the belt-like substrate 35 is heated to a predetermined temperature from its back surface by thermocouples 43 , 44 with their faces abutting on the back surface of the belt-like substrate while the temperature is monitored. The belt-like substrate 35 has its temperature lowered before passing through the gas gate 32 , and is heated to the predetermined temperature suitable for the film formation by the lamp heater 41 disposed before the deposited film forming space 37 , before reaching the deposited film forming space 37 . The lamp heater 42 disposed on the deposited film forming space 37 maintains the temperature to provide a constant temperature during the deposited film formation. Moreover, the lamp heaters 41 , 42 are provided with reflectors 45 of a double structure, so that light radiated from the lamp is collected onto the belt-like substrate 35 to increase heating efficiency and to prevent the lid 40 of the deposited film forming chamber 27 from being heated.

[0123] In the vicinity of the inlet and outlet in the deposited film forming chamber 27 , support rollers 46 are attached for rotatably supporting the back surface of the belt-like substrate 35 , so that the belt-like substrate 35 is linearly extended in the deposited film forming chamber 27 and supported from the back surface with an interval from the cathode electrode 7 kept constant. Furthermore, inside the support rollers 46 , permanent magnets (not shown) having a high Curie point are provided for generating magnetic forces to a degree to which the plasma is not influenced. When the belt-like substrate formed of ferrite stainless steel or another magnetic material is used, the support rollers 46 closely abut on the belt-like substrate 35 .

[0124] In the embodiment, the trap 21 is disposed between the deposited film forming space 37 and the exhaust piping 3 . Inside the trap 21 , the high-melting metal filament 22 is disposed like a straight line, and connected to a power supply (not shown) via a controller (not shown), so that power is supplied. Moreover, an inner wall surface of the trap 21 is of a double structure, and has a metal plate 47 attached thereto.

[0125] FIG. 7 shows a still further embodiment of the present invention. FIG. 7 is a schematic sectional view of a thermal CVD apparatus.

[0126] In FIG. 7, a wafer substrate 12 fixed to a substrate holder 11 is installed in a deposited film forming space 37 defined by quartz, whose pressure can be reduced by an exhaust pump 2 . Outside and close to the deposited film forming space 37 , halogen lamp haters 42 are vertically opposed to each other via the wafer substrate 12 . After the pressure of the deposited film forming space 37 is reduced to a desired pressure by the exhaust pump 2 , the wafer substrate 12 is heated to a desired temperature by the halogen lamp heaters 42 . Subsequently, SiH ₄ , Si ₂ H ₆ or another source gas is introduced from a gas introducing section 18 , and excited and decomposed by heat of the substrate. After a gas phase reaction or a surface reaction on the substrate, a deposited film is formed on the substrate 12 . A non-reacted gas and by-product are introduced to a trap 21 provided with a high-melting metal filament 22 . The non-reacted gas and by-product are removed in the same manner as in the aforementioned embodiment.

[0127] FIG. 8 shows another embodiment of the present invention. FIG. 8 is a schematic sectional view of a photo CVD apparatus.

[0128] In the drawing, numeral 49 denotes a quartz window, and 50 denotes a light source. Outside and close to a deposited film forming space 37 , a mercury lamp or another light source 50 is provided. The quartz window 49 is disposed so that ultraviolet rays emitted from the light source are radiated on a substrate 12 arranged in the deposited film forming space 37 . After the pressure of the deposited film forming space 37 is reduced to a desired pressure, the substrate 12 is heated to a desired temperature by the heater 42 . Subsequently, N ₂ O (nitrous oxide), Si ₂ H ₆ or another source gas is introduced, while the ultraviolet rays emitted from the light source 50 are transmitted through the quartz window 49 and radiated onto the substrate 12 . The source gas on the substrate 12 is excited and decomposed by the ultraviolet rays. After a gas phase reaction or a surface reaction on the substrate, a deposited film is formed on the substrate 12 . A non-reacted gas and by-product are introduced to a trap 21 provided with a high-melting metal filament 22 . The non-reacted gas and by-product are removed in the same manner as in the aforementioned embodiment.

[0129] A processing apparatus according to a second aspect of the present invention will be described hereinafter by way of specific examples, but the scope of the present invention is not limited to the following description.

[0130] An example of CVD apparatus as the processing apparatus of the present invention will be described. For example, to form an amorphous silicon film, an amorphous silicon alloy film, or another non-monocrystalline semiconductor thin film, a plasma CVD process is used. In one example of the apparatus of the present invention or apparatus shown in FIG. 9 , as a processing space, a reaction chamber 1000 formed of a stainless steel, quartz or the like is used. Via a gas mixing unit 1002 constituted of a mass flow controller or the like, a source gas formed by mixing silane gas (SiH ₄ ) and hydrogen gas (H ₂ ) at a desired ratio is introduced to the reaction chamber 1000 through a gas introducing pipe 1009 . Thereafter, a high-frequency power as decomposition energy is applied to a cathode electrode 1004 from a high-frequency power supply 1006 via a high-frequency applying cable 1011 to generate a discharge in a processing space (discharge space) 1012 , so that the source gas in the reaction chamber is decomposed, and a deposited film is formed on a desired processing substrate 1001 of stainless steel, glass or the like. A heater unit 1005 is provided on a back surface of the cathode electrode 1004 , thereby heating the substrate 1001 . Moreover, the pressure in the reaction chamber 1000 is monitored by a pressure gauge 1013 . Residual gas not formed into the deposited film (non-reacted gas, by-product) is passed as an exhaust gas through an exhaust pipe 1003 and a conductance valve 1014 , and exhausted to the outside of the reaction chamber via an exhaust gas piping 1010 by an exhaust pump unit 1008 . In this case, inside the exhaust pump 1003 , to cause a chemical reaction in the non-reacted gas or the by-product, there is provided a heating unit 1007 comprising phosphorus (P) atoms. The heating unit 1007 is connected to AC power supply 1015 via AC applying cable 1016 . The main component of the heat generating member is preferably at least one selected from the so-called high-melting metals consisting of chromium (Cr), molybdenum (Mo), tungsten (W), vanadium (V), niobium (Nb), tantalum (Ta), titanium (Ti), zirconium (Zr), hafnium (Hf) and the like, to which main component are added phosphorus (P) atoms for use. The content of phosphorus atoms is preferably not less than 0.1% in an atomic composition ratio relative to total atomic components constituting the heat generating member.

[0131] An effect of adding phosphorus atoms to the main component will next be described. For example, when a pure metal is selected as the material of the heat generating member, and heated and continued to be used as the heat generating member, a thermal processing effect of the heat generating member itself is produced dependent on the type of the metal. As a result, there is a case where a crystal grain diameter or another inner structure of the metal is varied, a high-temperature strength is lowered, and the metal becomes very brittle. Especially, even when the source gas to be introduced to the processing space contains no oxygen (O) atom, in an ordinary vacuum processing apparatus, an apparatus maintenance is performed in an open atmosphere in many cases. In this case, moisture (H ₂ O) or oxygen (O) is adsorbed to a surface of a member constituting an inner wall of the processing space exposed to the atmosphere. Therefore, to start the processing after the maintenance, the processing space is evacuated to vacuum, then the wall surface member or the like is heated to perform baking, or high-purity gas containing no oxygen (O) atom is used to perform purging several times. Even in this case, there is a gas containing at least oxygen (O) atoms of the order of ppm or more inside the processing space. The present gas containing the oxygen (O) atoms easily reacts with high-melting metal atoms constituting the heat generating member heated to a high temperature to oxidize the high-melting metal atoms. As a result, there is a case where properties of the heat generating member material are changed, tenacity is lowered and the member becomes brittle. To solve the problem, when the heat generating member containing phosphorus (P) atoms is used, the oxygen (O) atoms easily combine with the phosphorus (P) atoms rather than with the high-melting metal atoms. As a result, the high-melting metal atoms constituting the heat generating member are largely inhibited from being oxidized. Therefore, the high-temperature strength of the main component (metal) can be maintained and, as a result, the function of the heat generating member can be maintained longer, so that the present invention is effective even when the formation of amorphous silicon films or another processing is continuously performed over a long time as much as several hundreds of hours. Moreover, it can be said that since a damage cycle of heat generating member can be lengthened, the frequency of maintenance is decreased, and an operating efficiency of deposition apparatus can be enhanced.

[0132] For a position (location) where the heat generating member is installed, a section in the exhaust pipe 1003 disposed between the reaction chamber 1000 as the processing space and the exhaust pump unit 1008 such as a rotary pump and the like, i.e., the inside of an exhaust gas flow path is preferable. For example, as shown in FIG. 10A, a wire-like heat generating member 2001 is wound around an insulating plate 2000 a plurality of times, and at least one heating unit can be installed inside the exhaust pipe. Here, AC power or another power is applied to opposite ends of the wire-like heat generating member 2001 . If necessary, a voltage value of AC power may be adjusted by a voltage adjusting converter such as Slidac and the like. Moreover, as shown in FIG. 10 B, the heat generating member is formed as a coil-like heat generating member 2003 , and supported by an insulating rod member 2004 inserted through the heat generating member. At least one heat generating member is positioned across a gas flow direction inside the exhaust pipe, and AC power or the like may be applied to opposite ends of the coil-like heat generating member 2003 for use. Furthermore, as shown in FIG. 10 C, at least one rod-like heat generating member 2005 is used, and separate conductive electrodes 2006 are provided on opposite ends of the rod-like heat generating member so as to connect the rod-like heat generating members in parallel. AC power or the like may be applied to the conductive electrodes on opposite ends for use. Additionally, as shown in FIG. 10 D, at least one tape-like heat generating member 2007 is used, and separate conductive electrodes 2008 are provided on opposite ends of the tape-like heat generating member so as to connect the tape-like heat generating members in parallel. AC power or the like may be applied to the conductive electrodes on opposite ends for use. In any case, the heating unit is installed inside the exhaust pipe between the processing space and the exhaust means without obstructing the exhaust gas flow path. If such conditions are satisfied, the mode of installation is not limited.

[0133] In a method of heating the heat generating member, for the heat generating member of line, rod, coil or any other form, heat may be generated by applying AC power or DC power to opposite ends to pass an electric current through the heat generating member itself. If necessary, power may be applied via a temperature adjusting controller.

[0134] For the temperature of the heat generating member, for example, at the time of forming an amorphous silicon film, since the reaction for discharging a large amount of hydrogen (H) atoms contained in polysilane (Si _x H _y : x, y being integers) deposited in the exhaust pipe is promoted and, as a result, the film is changed to a silicon film piece, it is preferable to raise the temperature to 500° C. or more for use.

[0135] A processing apparatus according to a third aspect of the present invention will be described hereinafter by way of specific examples, but the scope of the present invention is not limited to the following description.

[0136] An example of CVD apparatus as the processing apparatus of the present invention will be described. For example, to form an amorphous silicon film, an amorphous silicon alloy film, or another non-monocrystalline semiconductor thin film, the plasma CVD process is used. In one example of the apparatus of the present invention or apparatus shown in FIG. 9 , as the processing space, the reaction chamber 1000 formed of stainless steel, quartz or the like is used. Via the gas mixing unit 1002 constituted of the mass flow controller or the like, a source gas formed by mixing silane gas (SiH ₄ ) and hydrogen gas (H ₂ ) at the desired ratio is introduced to the reaction chamber 1000 through the gas introducing pipe 1009 . Thereafter, the high-frequency power as decomposition energy is applied to the cathode electrode 1004 from the high-frequency power supply 1006 via the high-frequency applying cable 1011 to generate a discharge in the processing space (discharge space) 1012 , so that the source gas in the reaction chamber is decomposed, and the deposited film is formed on the desired processing substrate 1001 of stainless steel, glass or the like. The heater unit 1005 is provided on a back surface of the cathode electrode 1004 , thereby heating the substrate 1001 . Moreover, the pressure in the reaction chamber 1000 is monitored by the pressure gauge 1013 . Residual gas not formed into the deposited film (non-reacted gas, by-product) is passed as the exhaust gas through the exhaust pipe 1003 and the conductance valve 1014 , and exhausted to the outside of the reaction chamber via the exhaust gas piping 1010 by the exhaust pump unit 1008 . In this case, inside the exhaust pump 1003 , to cause the chemical reaction in the non-reacted gas or the by-product, there is provided a heating unit 1007 comprising silicon (Si) atoms. The heating unit 1007 is connected to AC power supply 1015 via AC applying cable 1016 . The main component of the heat generating member is preferably at least one selected from the so-called high-melting metals consisting of chromium (Cr), molybdenum (Mo), tungsten (W), vanadium (V), niobium (Nb), tantalum (Ta), titanium (Ti), zirconium (Zr), hafnium (Hf) and the like, to which main component are added silicon (Si) atoms for use. The content of silicon atoms is preferably not less than 0.1% in the atomic composition ratio relative to the total atomic components constituting the heat generating member.

[0137] An effect of adding silicon atoms to the main component will next be described. For example, when a pure metal is selected as the material of the heat generating member, and heated and continued to be used as the heat generating member, the thermal processing effect of the heat generating member itself is produced dependent on the type of the metal. As a result, there is a case where the crystal grain diameter or another inner structure of the metal is varied, the high-temperature strength is lowered, and the metal becomes very brittle. To solve the problem, when the heat generating member containing the silicon (Si) atoms is used, the high-temperature strength of the main component (metal) can be increased and, as a result, the function of the heat generating member can be maintained longer, so that the present invention is effective even when the formation of amorphous silicon films or another processing is continuously performed over a long time as much as several hundreds of hours. Moreover, it can be said that since the damage cycle of heat generating member can be lengthened, the frequency of maintenance is decreased, and the operating efficiency of deposition apparatus can be enhanced.

[0138] For the position (location) where the heat generating member is installed, a section in the exhaust pipe 1003 disposed between the reaction chamber 1000 as the processing space and the exhaust pump unit 1008 such as the rotary pump and the like, i.e., the inside of the exhaust gas flow path is preferable. As shown in FIG. 10 A, the wire-like heat generating member 2001 is wound around the insulating plate 2000 a plurality of times, and at least one heating unit can be installed inside the exhaust pipe. Here, AC power or another power is applied to opposite ends of the wire-like heat generating member 2001 . If necessary, the voltage value of AC power may be adjusted by the voltage adjusting converter such as Slidac and the like. Moreover, as shown in FIG. 10 B, the heat generating member is formed as the coil-like heat generating member 2003 , and supported by the insulating rod member 2004 inserted through the heat generating member. At least one heat generating member is positioned across the gas flow direction inside the exhaust pipe, and AC power or the like may be applied to opposite ends of the coil-like heat generating member 2003 for use. Furthermore, as shown in FIG. 10 C, at least one rod-like heat generating member 2005 is used, and separate conductive electrodes 2006 are provided on opposite ends of the rod-like heat generating member so as to connect the rod-like heat generating members in parallel. AC power or the like may be applied to the conductive electrodes on opposite ends for use. Additionally, as shown in FIG. 10 D, at least one tape-like heat generating member 2007 is used, and separate conductive electrodes 2008 are provided on opposite ends of the tape-like heat generating member so as to connect the tape-like heat generating members in parallel. AC power or the like may be applied to the conductive electrodes on opposite ends for use. In any case, the heating unit is installed inside the exhaust pipe between the processing space and the exhaust means without obstructing the exhaust gas flow path. If such conditions are satisfied, the mode of installation is not limited.

[0139] In the method of heating the heat generating member, for the heat generating member of line, rod, coil or any other form, heat may be generated by applying AC power or DC power to opposite ends to pass electric currents through the heat generating member itself. If necessary, power may be applied via the temperature adjusting controller.

[0140] For the temperature of the heat generating member, for example, at the time of forming the amorphous silicon film, since the reaction for discharging a large amount of hydrogen (H) atoms contained in polysilane (Si _x H _y : x, y being integers) deposited in the exhaust pipe is promoted and, as a result, the film is changed to a silicon film piece, it is preferable to raise the temperature to 500° C. or more for use.

[0141] FIG. 11 is a schematic sectional view showing an example of a deposited film forming apparatus as an example of a processing apparatus according to fourth and fifth aspects of the present invention. In the apparatus shown in FIG. 11, a vacuum container 3001 contains a processing chamber (plasma CVD chamber) 3003 . A source gas is supplied from gas supply means 3002 provided on one side of the plasma CVD chamber 3003 to perform a deposited film forming process by high-frequency glow discharge in the plasma CVD chamber 3003 . Furthermore, after the deposited film is formed, non-reacted gas and fine powder are discharged to exhaust means (vacuum pump) 3013 via an exhaust path (exhaust duct) 3004 and an exhaust piping 3005 provided on the other side of the plasma CVD chamber 3003 . A high-melting metal filament 3006 is disposed inside the exhaust duct 3004 between the processing chamber 3003 and the exhaust means 3013 . Here, as shown in FIG. 12 , intervals between exhaust duct wall surfaces 3015 a , 3015 b and the high-melting metal filament 3006 are L1, L2. In the embodiment the exhaust duct also serves as recovering means, but recovering means may be provided separately from the exhaust duct. Examples of such a recovering means include members in the shape of a plate, tray, net or rod, or a member also functioning as the chemical reaction causing means. The high-melting metal filament 3006 heated by supplying power from power controllers 3014 serves as chemical reaction causing means. Moreover, the exhaust duct wall surfaces 3015 a , 3015 b serve as recovering means of chemical reaction products. Formed between a plasma region in the processing chamber 3003 and the high-melting metal filament 3006 is a structure having no concave/convex portions, in order to produce no stagnation in gas flow. Moreover, provided inside the exhaust piping 3005 are a pressure adjusting valve 3011 and a gate valve 3012 . Here, a diluting gas is supplied together with source gas SiH ₄ to deposit an amorphous film on a substrate (not shown) set on a substrate holder 3010 in the plasma CVD chamber 3003 . In this case, the plasma CVD chamber 3003 is heated by a plasma CVD chamber heater 3008 , while the substrate is heated by a substrate heater 3007 . Moreover, power is supplied from RF power supply 3009 . The non-reacted gas and by-product exhausted from the processing chamber 3003 are stuck/collected as deposited films onto the exhaust duct inner wall surfaces.

[0142] Therefore, the attachment or deposition of the powder in the exhaust piping 3005 , valves 3011 , 3012 and pump 3013 as the exhaust means behind the exhaust duct is significantly reduced. Furthermore, reverse diffusion of the powder deposited in the exhaust duct 3004 is eliminated,