JP4788504B2 - Power supply structure for plasma processing equipment - Google Patents

Description

  The present invention relates to a power supply structure in a plasma processing apparatus that uses plasma to perform processing such as thin film deposition and etching on the surface of a substrate.

A plasma processing technique for generating a plasma by applying a voltage and flowing a gas between two electrodes arranged opposite to a substrate in a vacuum vessel, and performing thin film formation and etching using this plasma, Conventionally, it has been applied in many technical fields.
As an apparatus of such a plasma processing technique, for example, a capacitively coupled parallel plate plasma CVD apparatus or an etching apparatus can be cited.
In this parallel plate plasma CVD apparatus or etching apparatus, if the gas flowing in the vacuum vessel in which the substrate is arranged is a film forming gas typified by SiH ₄ , for example, a thin film is deposited on the substrate, If an etching gas typified by CF ₄ is used, the substrate is etched.
Here, an example will be given in which a thin film solar cell is manufactured by a plasma CVD method in which a Si-based thin film is formed on a substrate with a gas mainly containing SiH ₄ .

FIG. 5 is a schematic view of a plasma processing apparatus using a capacitively coupled parallel plate plasma CVD method.
In FIG. 5, a high-frequency electrode 6 to which high-frequency power is supplied from an external high-frequency power source 3 through a matching circuit 4 and a feed line 5 is supplied to a vacuum chamber 2a formed inside the vacuum vessel 2 of the plasma processing apparatus 1, and a substrate. A ground electrode 7 is arranged at a position facing the high-frequency electrode 6 with 8 interposed therebetween. The vacuum vessel 2 and the power supply line 5 are electrically insulated. Note that the ground electrode 7 is not necessarily at the ground potential, and may have a mechanism capable of applying direct current or high frequency power depending on the purpose.

A mechanism (not shown) for installing the substrate 8 is provided above the ground electrode 7, and a heating mechanism for heating the substrate 8 is built in the ground electrode 7. The installation position of the substrate 8 may be an arbitrary place in the vacuum chamber 2a, for example, on the high-frequency electrode 6. Further, the presence or absence of the heating mechanism in the ground electrode 7 or the installation location of the heating mechanism is not limited.
The contact position between the power supply line 5 and the high-frequency electrode 6 is usually at the center of the high-frequency electrode 6, and the high-frequency electrode 6 and the power supply line 5 are in vertical contact with each other, as viewed from the high-frequency electrode 6 side. Thus, the feeder line 5 is arranged symmetrically.

6 and 7 are schematic views of a plasma processing apparatus showing another example of the arrangement relationship between the high-frequency electrode and the power supply line.
In the plasma processing apparatus using the plasma CVD method shown in FIG. 6, the contact portion between the feeder 5 and the high-frequency electrode 6 is not the central portion of the high-frequency electrode 6 as in the apparatus of FIG. It is arranged in the part. The other structure is the same as that of FIG. 5, and the same member is shown with the same code | symbol.

In the plasma processing apparatus shown in FIG. 7, the contact portion between the power supply line 5 and the high-frequency electrode 6 is disposed at the center of the high-frequency electrode 6 (may be slightly shifted from the center), and externally. A high-frequency power source 3 is arranged on the upper part of the vacuum vessel 2, and a power supply line 5 for introducing power from the high-frequency power source 3 is introduced into the vacuum chamber 2 a from the upper wall of the vacuum vessel 2. Therefore, the power supply line 5 that connects the external high-frequency power source 3 side and the high-frequency electrode 6 is not linear but L-shaped, and is asymmetrically arranged when viewed from the high-frequency electrode 6 side.
Such a structure is employed when the power introduction form from the external high-frequency power source 3 cannot take the configuration as shown in FIG.
The other structure is the same as that of FIG. 5, and the same member is shown with the same code | symbol.

The plasma processing apparatus shown in FIG. 8 is configured to install a plurality of high-frequency electrodes and ground electrodes in the vacuum chamber 2a.
That is, in FIG. 8, high-frequency electrodes 6a and 6b to which high-frequency power is supplied from two high-frequency power sources 3a and 3b through power supply lines 5a and 5b are opposed to the high-frequency electrodes 6a and 6b, respectively. Ground electrodes 7a and 7b (in place of the ground electrodes 7a and 7b, a mechanism capable of applying direct current or high-frequency power depending on the purpose) may be installed at positions. A mechanism (not shown) for installing the substrates 8a and 8b is provided above the ground electrodes 7a and 7b, and a heating mechanism for heating the substrates 8a and 8b is provided in the ground electrodes 7a and 7b. Yes.
In such a plasma processing apparatus, two sets of high-frequency electrodes 6a and 6b and ground electrodes 7a and 7b are installed in a vacuum chamber 2a, and a high-frequency power source 3a disposed for each of the high-frequency electrodes 6a and 6b. , 3b, it is possible to apply power independently.
By adopting such a configuration, the processing capability can be doubled as compared with a plasma processing apparatus in which one set of the high-frequency electrode 6 and the ground electrode 7 as shown in FIGS.
By using a plasma processing apparatus as shown in FIG. 8 to produce a thin film solar cell on a flexible substrate made of a long polymer material or a metal material such as stainless steel, the productivity of the thin film solar cell is improved. It becomes possible to do. The other structure is the same as that of FIG. 5, and the same member is shown with the same code | symbol.

Next, a procedure for forming a thin film on a substrate using a plasma processing apparatus as shown in FIGS. 5 to 8 will be described taking the apparatus of FIG. 5 as an example.
First, the inside of the vacuum chamber 2a is evacuated to a required degree of vacuum by an exhaust means (not shown). Next, the substrate 8 is heated by a heater in the ground electrode 73 as necessary.
Immediately after evacuation, impurities such as moisture are often adsorbed in the vacuum chamber 2a, the surface of the substrate 8, and the like, and if these impurities are not sufficiently degassed, Since a large amount of impurities are included, the film quality is degraded. Therefore, for the purpose of promoting degassing in the vacuum chamber 2a, gas is introduced from the gas introduction line before forming the thin film, and the vacuum chamber 2a is kept at a constant pressure by the pressure controller and the film forming gas exhaust line. The inside of the vacuum chamber 2a is heated (baked).
As the gas to be flowed during the baking, a gas having relatively good thermal conductivity such as H ₂ , an inert gas such as He or Ar, or a film forming gas to be flowed during film formation is employed. Further, the substrate temperature during baking may be set higher than the substrate temperature at the time of actual film formation. This is because the degassing is promoted by setting the substrate temperature during baking higher than the substrate temperature during film formation, and the amount of degassing during film formation is reduced.
After the degassing, the substrate temperature is set to the substrate temperature at the time of film formation, and if necessary, a mixed gas obtained by mixing several kinds of film formation gases at a predetermined flow rate ratio is allowed to flow into the vacuum chamber 2a to obtain a required pressure. Then, a voltage is applied to the high-frequency electrode 6 to generate plasma between the high-frequency electrode 6 and the ground electrode 7 to form a thin film on the substrate 8. By forming a multilayer film on the substrate 8 under various film forming conditions, a thin film solar cell or the like can be manufactured.

In the prior art shown in FIG. 5 to FIG. 7, as for the connection mode between the feeder line 5 and the high-frequency electrode 6, the connection part between the feeder line 5 and the high-frequency electrode 6 is as in the examples shown in FIGS. 5 and 7. In some cases, the center portion of the high-frequency electrode 6 is connected to the feeder line 5 and the high-frequency electrode 6 vertically as in the example shown in FIG. In the case of the example shown in FIG. 5, a mechanism (including the high-frequency power source 3 and the matching circuit 4) that supplies power from the outside into the vacuum chamber 2 a is disposed at a side position with respect to the vacuum container 2.
On the other hand, in the example shown in FIGS. 6 and 7, a mechanism for supplying electric power from the outside into the vacuum chamber 2 a is disposed at an upper position with respect to the vacuum container 2. In particular, in the example shown in FIG. 7, the connection site between the feeder 5 and the high-frequency electrode 6 is the center of the high-frequency electrode 6, but a mechanism for supplying electric power from the outside into the vacuum chamber 2 a is connected to the vacuum vessel 2. The feeder 5 that is disposed at the upper position and connects the high-frequency electrode 6 to the mechanism for supplying electric power from the outside into the vacuum chamber 2a is longer than in the case of FIGS.

As shown in FIG. 5 to FIG. 7, in the example shown in FIG. 8, a plurality of high-frequency electrodes 6 and a plurality of high-frequency electrodes 6 and a ground electrode 7 are installed in the vacuum chamber 2 a. A ground electrode 7 is provided.
That is, in the example shown in FIG. 8, two sets of high-frequency electrodes 6a and 6b and ground electrodes 7a and 7b are installed in the vacuum chamber 2a, and the high-frequency power source disposed for each of the high-frequency electrodes 6a and 6b. 3a, 3b and matching circuits 4a, 4b are configured to be able to supply power independently.

That is, in the example shown in FIG. 8, when the power supply lines 5a and 5b are connected and arranged near the center of the high-frequency electrodes 6a and 6b, the shapes of the power supply lines 5a and 5b are shown in FIG. The linear shape as shown in FIG. 5 cannot be formed, and the L shape is formed similarly to the example shown in FIG.
However, in the example shown in FIG. 8, the shape of the power supply lines 5a and 5b is such that the mechanism for supplying power from the outside into the vacuum chamber 2a is installed, and the power supply lines 5a and 5b and the high-frequency electrodes 6a and 6b. Although it depends on the connection position, when high-frequency power is used, an inductance component according to the length and shape of the feeder lines 5a and 5b exists, and the connection point between the matching circuits 4a and 4b and the feeder lines 5a and 5b is excessive. Since a voltage is generated, it is preferable to connect the feeder lines 5a and 5b as wide and short as possible.

On the other hand, as the material of the power supply line 5 (5a, 5b), a metal having a low resistivity such as silver or copper is often selected, and the shape thereof is selected to be linear, plate, or cylindrical. Often.
As in the example shown in FIG. 8, when high-frequency power is used as a power source and the power supply lines 5 (5a, 5b) become long, a high voltage is generated in the power supply lines 5 (5a, 5b), and various values are generated inside and outside the vacuum vessel 2. Will be affected. For example, when the feeder 5 (5a, 5b) is present in the reaction chamber to which plasma is applied, the periphery of the feeder 5 (5a, 5b) is also filled with the reaction gas, and the feeder 5 (5a, 5b) If there is a reaction chamber wall body (wall body of the vacuum vessel 1) having a ground potential at a position separated from 5b) by an appropriate distance, a discharge occurs between the feeder 5 (5a, 5b) and the reaction chamber wall body. As a result, a problem such as adhesion or etching of a thin film in the vicinity of a region where power loss or plasma is generated occurs. Further, a high voltage is applied to the matching circuit 4, which causes a problem that dielectric breakdown easily occurs in the matching circuit 4.
As a measure against unnecessary discharge in the vacuum vessel 2a, a shield plate 12 is inserted between the high-frequency electrode 6 to which a high-frequency voltage is applied and the power supply line 5 as shown in FIG. It has been proposed to perform good plasma processing by connecting both ends of 12 to a ground potential portion to weaken electromagnetic interference.

FIG. 10 is a schematic cross-sectional view showing the power supply structure of the plasma processing apparatus shown in FIG.
In FIG. 10, the plate-like or cylindrical feeder 5 is connected to the terminal of the matching circuit 4, penetrates the vacuum vessel 2 through the insulating sealing material 21, enters the vacuum chamber 2 a, and enters the high-frequency electrode 6. It is connected to the back side of the high frequency power supply. In such a configuration, the service hatch 22 for connecting the power supply line 5 on the back side of the high-frequency electrode 6 is required. The other structure is the same as that of FIG. 7, and the same member as FIG. 7 is shown with the same code | symbol.

Further, Patent Document 1 (Japanese Patent Laid-Open No. 8-293491) proposes a multi-row substrate transport film forming apparatus using a stepping roll system equipped with a plasma processing apparatus.
In such a plasma processing apparatus, a high-frequency electrode and a ground electrode are provided between two rows of substrates that are transported in parallel in a vacuum chamber formed inside the vacuum vessel, and each applies a voltage that is opposed to each other. A high-frequency current from a high-frequency power source installed outside the vacuum vessel is supplied to the high-frequency electrode through a power supply line, and a voltage is applied to the film-forming chamber that becomes airtight during film formation, forming a thin film on the surface of the substrate Plasma for this purpose is generated in the film forming chamber.
JP-A-8-293491

In the plasma processing apparatus (plasma CVD apparatus) in which a plurality of high-frequency electrodes 6a and 6b and ground electrodes 7a and 7b are installed in the vacuum chamber 2a as in the prior art shown in FIG. 8, the high-frequency electrodes 6a and 6b When high-frequency power is supplied through the power supply lines 5a and 5b, electromagnetic interference is likely to occur, and there is a possibility of causing a problem that power supply energy cannot be sufficiently supplied to the high-frequency electrodes 6a and 6b.
As a means for coping with this problem, electromagnetic interference is reduced by using a coaxial cable or the like in which a shield body (outer conductor) is provided on the outer periphery of the feeders 5a and 5b (center conductor). Means for performing an appropriate plasma treatment are known.
Conventionally, in the feeders 5a and 5b composed of the coaxial cable of the outer peripheral conductor and the central conductor, the shape of the central conductor is conventionally a thread shape, a square shape, and a cylindrical shape, and the outer peripheral conductor shape is a circular tube. The shape is a square tube shape. However, since the power supply lines 5a and 5b need to be impedance-matched, it is necessary to set the optimum inductance and capacitance by selecting an appropriate conductor size and securing an appropriate distance between the center conductor and the outer conductor. is there.

On the other hand, in recent years, large-area film formation technology for forming a thin film on a large substrate has been rapidly advanced, and research on large-area film formation for forming a thin film on a 1 m class substrate has been conducted for the purpose of improving productivity. Has been made. In a plasma CVD apparatus in which a plurality of high-frequency electrodes 6a and 6b and ground electrodes 7a and 7b are installed in a vacuum chamber 2a as shown in FIG. 8, a thin film is formed on substrates 8a and 8b having a width dimension exceeding 1 m. For this purpose, the width dimensions of the high-frequency electrodes 6a and 6b are increased to more than 1 m.
As a result, the feeder lines 5a and 5b also become longer and the loss tends to increase, and the supplied power also needs to be input up to several kW to 5 kW.
For this reason, the feed lines 5a and 5b have a structure in which a central conductor made of silver or copper is passed through the outer conductor having a shield function, thereby providing a shield function and preventing electromagnetic interference. By using a coaxial cable, a low-loss feed line can be obtained.

On the other hand, in order to obtain a thin film having good film quality, the temperature of the high-frequency electrode 6 needs to be raised to over 200 ° C. On the other hand, the feed line 5 is located near the center of the back surface of the high-frequency electrode 6 as in the examples shown in FIGS. 5, 7 and 8, or at the end of the high-frequency electrode 6 as in the example shown in FIG. Each must be connected.
For this reason, in such a conventional technique, there arises a problem that the power supply line 5 is heated due to a temperature rise due to heat conduction from the high-frequency electrode 6.

Further, in the plasma CVD apparatus in which a plurality of high-frequency electrodes 6a and 6b and ground electrodes 7a and 7b are installed in the vacuum chamber 2a as shown in FIG. 8, the high-frequency electrodes 6a and 6b are required due to the demand for reducing the apparatus space. It may be necessary to shorten the distance between.
In such a case, in order to reduce the space on the back side of the high-frequency electrodes 6a and 6b and the ground electrodes 7a and 7b, the high-frequency electrodes 6a and 6b are incorporated in a state where the power supply lines 5a and 5b are connected in advance, and the vacuum container is installed in the upper space. 2 need to be connected to the feeders 5a and 5b from the outside.
In such a conventional technique, since it is necessary to attach the feeders 5a and 5b in a long and unstable form to the high-frequency electrodes 6a and 6b in the vacuum vessel 2, There is a possibility that excessive stress may occur at the connection between the power supply lines 5a and 5b and the high-frequency electrodes 6a and 6b, and at the time of assembly, the connection between the power supply lines 5a and 5b and the high-frequency electrodes 6a and 6b is visually inspected. Since it is difficult to retighten, there are problems such as a power supply structure with poor maintainability.

  The present invention has been made in view of such a situation, and the purpose of the present invention is to suppress the temperature rise of the feeder line and to connect to the electrode even in a large-sized plasma CVD apparatus that performs large-area film formation. An object is to provide an easy power supply structure for a plasma processing apparatus.

  In order to solve the above-described problems of the prior art, the present invention includes a high-frequency electrode and a ground electrode arranged to face a substrate in a vacuum vessel, and a high-frequency power source is supplied between the high-frequency electrode and the ground electrode. In a plasma processing apparatus in which a plasma is generated by applying a voltage and flowing a gas by high-frequency power supply via an electric wire, and performing plasma processing such as film formation and etching on the surface of the substrate, the power supply line is upstream The cross-sectional area on the high-frequency power source connection side on the side is large, and the cross-sectional area on the high-frequency electrode connection side on the downstream side is smaller than the cross-sectional area on the high-frequency power source connection side.

In the present invention, the following configuration is specifically preferred.
That is, the power supply line includes a power supply flange connected to the high frequency power supply side, a power supply flange connection side power supply line connected to the downstream side of the power supply flange, and an electrode connection side power supply line connected to the high frequency electrode. The power supply flange connection side power supply line and the main power supply line connecting the electrode connection side power supply line are formed, and the surface area of the electrode connection side power supply line is equal to or larger than the surface area of the main power supply line. .

  In the present invention, a cooling water passageway through which cooling water for cooling the power supply line flows is provided in a power supply flange attached to the vacuum vessel on the upstream side of the power supply line.

  Furthermore, the present invention provides a square flange having a guide pin at the high-frequency electrode side end portion downstream of the feeder line, and embeds it in a square groove portion provided on the back side of the high-frequency electrode. A guide pin type coupling structure in which the high-frequency electrode is sandwiched between a flange having a guide pin insertion hole into which the high-frequency electrode can be inserted and the square-shaped flange so that the feed line and the electrode can be connected from the front side of the high-frequency electrode The electrode connection flange part which consists of is provided.

In addition to the present invention, the following configuration is possible.
That is, in a plasma CVD apparatus provided with a plurality of high-frequency electrodes and a plurality of ground electrodes, an electrode connection flange portion composed of the guide pin type connection structure of the power supply line is disposed in a space between the plurality of high-frequency electrodes. Yes.

According to the present invention, even when the high-frequency electrode reaches a high temperature exceeding 200 ° C., the cross-sectional area on the high-frequency power source connection side on the upstream side of the feeder line is increased, and the cross-sectional area on the high-frequency electrode connection side on the downstream side is increased. The cross-sectional area of the high-frequency power supply connection side is formed smaller than the cross-sectional area of the power supply line, specifically, the cross-sectional area of the electrode connection-side power supply line is smaller than the cross-sectional area of the main power supply line, Since it is formed larger than the cross-sectional area of the electric wire, the thermal resistance is increased by making the cross-sectional area of the electrode connection side power supply line of the power supply line smaller than the cross-sectional area of the main power supply line connected to the inlet terminal, It becomes possible to reduce the amount of heat transfer from the high-frequency electrode side to the feeder line side.
Further, by making the cross-sectional area of the power supply flange connection side power supply line on the vacuum vessel side in the power supply line larger than the cross-sectional area of the main power supply line, the heat transfer amount from the high-frequency electrode and the self-heat generation amount of the power supply line accompanying the high-frequency power supply It is possible to transfer heat to the power supply flange side outside the vacuum vessel to promote heat dissipation. Thereby, the maximum temperature of the feeder can be suppressed to an allowable value of 200 to 250 ° C. or less.

  In addition, due to the temperature drop of the power supply line as described above, a heat-resistant and excellent workability is formed on the gap piece made of an insulating material inserted between the main power supply line of the power supply line and the inner surface of the outer peripheral conductor covering the power supply line. Resin material can be used, and the manufacturing cost of the spacing piece can be reduced, and the increase in electric resistance in the feeder line can be suppressed without passing coolant such as cooling water through the vacuum vessel. As a result, a highly reliable power feeding structure with no fear of water leakage in the vacuum vessel is obtained.

  Further, when the cross-sectional area of the power supply line is reduced by reducing the plate thickness, diameter, etc. of the electrode connection side power supply line on the high frequency electrode connection side, the flexibility of the power supply line is increased. The increase in flexibility of the power supply line improves the connection workability between the power supply line and the high-frequency electrode, and the amount of thermal expansion associated with the temperature rise during film formation can be reduced with a small cross-sectional area and a flexible electrode connection side power supply line. It is also possible to absorb at this portion, and it is possible to prevent excessive thermal stress from being generated in the high frequency electrode and the power supply line, and the durability of the high frequency electrode and the power supply line is improved.

Furthermore, according to the present invention, by cooling the power supply line with the cooling water flowing through the cooling water flow path provided in the power supply flange of the power supply line, the heat dissipation from the power supply line is suppressed, and the surroundings due to the heat dissipation The effect on temperature can be reduced, more stable power line temperature management is possible, and by adjusting the cooling water temperature and the amount of cooling water, it is possible to keep the power line at a low temperature, and the resistance of the power line By suppressing the increase in value, the amount of self-heating of the feeder line can be reduced.
Thereby, damage and carbonization of the insulating member around the power supply line due to the temperature rise of the power supply line can be prevented, and good insulation can be maintained for a long time.
In addition, since the cooling water passage is provided only at the power supply flange outside the vacuum vessel, there is no concern of water leakage from the cooling water passage into the vacuum vessel, and a highly reliable plasma CVD apparatus and Become.

Then, according to the present invention, from the front side of the high-frequency electrode, the high-frequency electrode is sandwiched between the rectangular flange on which the guide pin is temporarily fixed and the flange having the guide pin insertion hole. By providing an electrode connection flange portion composed of a guide pin type connection structure for connecting to the high frequency electrode, it becomes possible to connect the high frequency electrode and the power supply line from the front side of the high frequency electrode. Connection space can be saved, and the vacuum vessel can be miniaturized.
In addition, by fitting a square flange into the square groove provided on the back side of the high-frequency electrode, it is possible to prevent the square flange from co-rotating, and the power supply line is deformed or cut by the torque accompanying the co-rotation. Can be prevented.

  Further, according to the present invention, it is possible to reduce the electrode installation space on the back side of the plurality of high-frequency electrodes, it is possible to shorten the distance between the plurality of high-frequency electrodes, and after assembling the high-frequency electrodes, Since the power supply line can be connected from the front side of the high-frequency electrode, connection workability of the power supply line to the high-frequency electrode can be improved. Further, it is easy to visually check and retighten the connection state of the power supply line, and a power supply structure with good maintainability can be obtained.

  Below, the insulation structure of the plasma processing apparatus which concerns on this invention is demonstrated in detail based on the embodiment.

[First embodiment]
FIG. 1 is a schematic sectional view of a plasma CVD apparatus according to the first embodiment of the present invention.
In FIG. 1, 1 is a plasma CVD apparatus, 2 is a vacuum vessel, and a vacuum chamber 2 a is formed inside the vacuum vessel 2. In this vacuum chamber 2a, a high-frequency electrode 6 and a ground electrode 7 for applying a voltage that is opposed to each other are provided between the substrate 8 and the substrate 8, and the high-frequency electrode 6 and the ground electrode 7 provide A voltage is applied to the film formation chamber 2b which is in an airtight state during film formation, and plasma for forming a thin film on the surface of the substrate 8 is generated in the film formation chamber 2b.

A feeding line 5 is connected to the high-frequency electrode 6, and the feeding line 5 is connected to a high-frequency power source 3 through a matching circuit 4 installed outside, and a high-frequency current from the high-frequency power source 3 is matched. It is applied to the high-frequency electrode 6 through the circuit 4 and the feeder line 5.
The power supply line 5 is formed in a plate shape, and is connected to the outlet terminal of the matching circuit 4, the power supply flange 54 connected to the outlet terminal of the power supply flange 54, and the L-shaped power supply flange connection side The feed line 53, the main feed line 52 connected to the exit terminal of the feed flange connection side feed line 53, and the electrode connection side feed line connecting the exit terminal of the main feed line 52 and the center of the back surface of the high-frequency electrode 6 51.
Further, in the feeder line 5, the sectional area of the electrode connection side feeder line 51 is smaller than the sectional area of the main feeder line 52, and the sectional area of the feeder flange connection side feeder line 53 is larger than the sectional area of the main feeder line 52. It has a configuration. In addition, the electrode connection side power supply line 51 has both ends of the high-frequency electrode 6 and the main power supply line 52 that are clamped in parallel, and the intermediate part has a substantially crank shape with a downward inclined surface from the main power supply line 52 toward the high-frequency electrode 6. Is formed.
An insulating sealing material 21 is interposed between the outer periphery of the power supply flange 54 and the vacuum vessel 2.

The vacuum vessel 2 is provided with a hollow outer peripheral conductor 9 made of an insulating material. The outer peripheral conductor 9 is fixed to the inner surface of the vacuum vessel 2 with its upper end grounded, and is placed in the vacuum chamber 2a. Protrusively arranged. The portion below the power supply flange 54 of the power supply line 5, that is, the power supply flange connection side power supply line 53, the main power supply line 52, and the electrode connection side power supply line 51 are covered with the outer peripheral conductor 9, and the vacuum chamber 2a. Is placed inside.
Further, a plurality of (two in this embodiment) spacing pieces 91 are interposed between the main feeding line 52 of the feeding line 5 and the inner surface of the outer peripheral conductor 9. Is formed from a heat-resistant resin material having good processability, for example, a material such as Teflon (registered trademark) (PTFE), polyamideimide (PAI), or the like. In addition, by adjusting the thickness t of the spacing piece 91, the mounting position of the feeder line 5 in the outer peripheral conductor 9 can be adjusted.

Next, an outline of the operation during film formation in the plasma CVD processing apparatus according to the first embodiment of the present invention will be described.
In FIG. 1, at the time of film formation, an actuator (not shown) conveys the substrate 8 that is transported into the vacuum chamber 2a of the vacuum vessel 2 and stopped in the ground electrode 7 and the film formation chamber 2b to a ground electrode support frame (not shown). An airtight film formation chamber 2 b is formed between the high-frequency electrode 6 and the substrate 8.
Then, the output voltage of the high frequency power supply 3 is supplied to the central portion of the high frequency electrode 6 through the matching circuit 4 and the power supply line 5, and a high frequency voltage is applied between the high frequency electrode 6 and the ground electrode 7. As a result, plasma is generated in the film forming chamber 2b, the reaction gas introduced from an introduction pipe (not shown) is decomposed, and is heated on the surface of the substrate 8 heated by a heater (not shown) built in the ground electrode 7. Thus, a thin film is formed.

As described above, according to the first embodiment of the present invention, even when the high-frequency electrode 6 reaches a high temperature exceeding 200 ° C., the cross-sectional area of the electrode connection side power supply line 51 of the power supply line 5 is connected to the inlet terminal thereof. By making it smaller than the cross-sectional area of the main power supply line 52, the amount of heat transfer from the high frequency electrode 6 side to the power supply line 5 side can be reduced.
Further, by making the surface area of the power supply flange connection side power supply line 53 in the power supply line 5 equal to or larger than the surface area of the main power supply line 52, the self-heating amount of the power supply line 5 accompanying the high frequency power supply from the high frequency electrode 6 can be reduced. It becomes possible to reduce.
Thereby, the maximum temperature of the feeder 5 can be suppressed to 200 to 250 ° C. or less.

  Therefore, due to the temperature drop of the power supply line 5 as described above, the space piece 91 made of an insulating material inserted between the main power supply line 52 of the power supply line 5 and the inner surface of the outer peripheral conductor 9 is heat resistant with good workability. It is possible to use a resin material such as Teflon (registered trademark) (PTFE), polyamideimide (PAI), and the like, and the manufacturing cost of the spacing piece 91 can be reduced. It is possible to suppress an increase in electrical resistance in the power supply line 5 without passing water therethrough, and a highly reliable power supply structure without the fear of water leakage in the vacuum vessel 2 can be obtained.

In addition, when the cross-sectional area of the power supply line 5 is reduced by reducing the plate thickness, diameter, etc. of the electrode connection side power supply line 51, the flexibility of the power supply line 5 is increased. For example, in the plate-like power supply line 5 as in the first embodiment, when the plate thickness decreases, the electrode connection-side power supply line 51 has a thickness of about 0.5 mm to 1.5 mm. Flexibility is obtained.
The increase in flexibility of the power supply line 5 improves the connection workability between the power supply line 5 and the high-frequency electrode 6, and the amount of thermal expansion accompanying the temperature increase during film formation can be reduced and the electrode connection can be made with a small cross-sectional area. It is possible to absorb the portion of the side power supply line 51, and it is possible to prevent excessive thermal stress from being generated in the high frequency electrode 6 and the power supply line 5, and the durability of the high frequency electrode 6 and the power supply line 5 is improved. .

[Second Embodiment]
FIG. 2 is a schematic sectional view of a plasma CVD apparatus according to the second embodiment of the present invention.
In the second embodiment of the present invention, the cooling water water passage 10 is provided in the power supply flange 54, and the power supply line 5 is cooled by the cooling water flowing through the cooling water water passage 10. Yes. The other structure is the same as that of 1st Embodiment shown in FIG. 1, and the member same as this is shown with the same code | symbol.

According to the second embodiment, by cooling the power supply line 5 with the cooling water flowing through the cooling water flow path 10 provided in the power supply flange 54 of the power supply line 5, heat radiation from the power supply line 5 is suppressed. The influence of the heat radiation on the ambient temperature can be reduced, the power supply line 5 can be controlled more stably, and the power supply line 5 can be kept at a low temperature by adjusting the cooling water temperature and the cooling water amount. Thus, an increase in the resistance value of the feeder line 5 can be suppressed, and the amount of self-heating of the feeder line 5 can be reduced.
Thereby, damage and carbonization of the insulating member around the power supply line 5 due to the temperature rise of the power supply line 5 can be prevented, and good insulation can be maintained for a long time.
Further, since the cooling water passage 10 is provided only on the power supply flange 54 outside the vacuum vessel 2, there is no concern about leakage of water from the cooling water passage 10 into the vacuum vessel 2, and the reliability is high. A plasma CVD apparatus is obtained.

[Third Embodiment]
3A and 3B show a plasma CVD apparatus according to a third embodiment of the present invention, in which FIG. 3A is a schematic sectional view (a diagram corresponding to FIG. 1), and FIG. 3B is an enlarged view of a Y portion in FIG.
In 3rd Embodiment of this invention, the connection part of the feeder 5 and the high frequency electrode 6 is comprised by the electrode connection flange part 11 of a guide pin type | mold connection structure.
That is, in FIGS. 3A and 3B, in the electrode connection flange portion 11 having such a guide pin type coupling structure, a plurality (2 in this embodiment) are provided at the end of the electrode connection side power supply line 51 of the power supply line 5. This is provided by fixing a square flange 11a having a guide pin 11b temporarily fixed to the end with a plurality of screws 51a, and the square flange 11a is fitted into a square groove 61 provided on the back side of the high-frequency electrode 6. ing.
Further, the flange 11c having the guide pin insertion hole 11f into which the guide pin 11b is inserted is fitted into a square groove portion 62 provided on the front side of the high frequency electrode 6 (side facing the substrate 8).

The square flange 11a and the flange 11C are positioned by inserting the guide pin 11b into the guide pin insertion hole 11f, and the high frequency electrode 6 is sandwiched between the square flange 11a and the flange 11c. The power supply line 5 and the high frequency electrode 6 are connected by tightening the square flange 11a and the flange 11C from the side with the tightening screw 11e.
The other structure is the same as that of 1st Embodiment shown in FIG. 1, and the member same as this is shown with the same code | symbol.

According to the third embodiment, the high-frequency electrode 6 is sandwiched between the rectangular flange 11a on which the guide pin 11b is temporarily fixed and the flange 11c having the guide pin insertion hole 11f, and the tightening screw is inserted from the front side of the high-frequency electrode 6. By tightening 11e and connecting the power supply line 5 and the high frequency electrode 6, the high frequency electrode 6 and the power supply line 5 can be connected from the front side of the high frequency electrode 6; The connection space of the electric wire 5 can be saved and the vacuum vessel 2 can be reduced in size.
Further, by fitting the square flange 11a into the square groove portion 61 provided on the back surface side of the high-frequency electrode 6, it is possible to prevent the square flange 11a from rotating together. It is possible to prevent the electric wire 5 from being deformed.

Furthermore, according to the third embodiment of the present invention, the high frequency electrode 6 and the flange 11c are adjusted to the guide pin 11b by adjusting the length of the guide pin 11b fixed to the square flange 11a on the power supply line 5 side. Accordingly, it is possible to pull out to the front side of the high-frequency electrode 6 and easily align the square flange 11a and the flange 11c having the guide pin insertion hole 11f.
In addition, the guide pin 11b is temporarily fixed to the end of the square flange 11a, and the high frequency electrode 6 is sandwiched between the square flange 11a and the flange 11c to tighten and supply the tightening screw 11e from the front side of the high frequency electrode 6. Since the electric wire 5 and the high-frequency electrode 6 are connected, the guide pin 11b can be extracted when plasma processing is performed after the connection between the high-frequency electrode 6 and the power supply line 5 using the guide pin 11b as a guide. Therefore, it is possible to avoid the influence on the film formation due to the electrolytic concentration due to the installation of the guide pin 11b. Further, if the guide pin 11b is detachable by screw connection or the like, the guide pin 11b can be removed and the maintainability is improved.

[Fourth Embodiment]
FIG. 4 is a schematic sectional view showing a plasma CVD apparatus according to the fourth embodiment of the present invention.
In the fourth embodiment of the present invention, in a plasma CVD apparatus provided with a plurality of high-frequency electrodes 6 and 6 and a plurality of ground electrodes 7 and 7, as in the third embodiment, the connection between the feeder line and the high-frequency electrode is performed. The portion is constituted by an electrode connecting flange portion 11 having a guide pin type connecting structure.
That is, the basic configuration of the fourth embodiment is similar to the plasma CVD apparatus shown in FIG. 8, in which two sets of high-frequency electrodes 6 and 6 and ground electrodes 7 and 7 are installed in the vacuum chamber 2a. The high-frequency power sources 3 and 3, the matching circuits 4 and 4, and the feeder lines 5 and 5 arranged with respect to the high-frequency electrodes 6 and 6 can supply power independently. And in this 4th Embodiment, the connection part of the feeders 5 and 5 and the high frequency electrodes 6 and 6 is the guide pin type connection structure 11 and 11 similar to the said 3rd Embodiment with respect to this basic composition. It is configured. The structure of the electrode connection flange portions 11 and 11 having such a guide pin type coupling structure is the same as that shown in FIG.
In FIG. 4, the same members as those in FIG. 3 are denoted by the same reference numerals.

  According to the fourth embodiment, the electrode installation space on the back side of the high-frequency electrodes 6 and 6 can be saved, the distance between the high-frequency electrodes 6 to 6 can be shortened, and the high-frequency electrodes 6 and 6 can be shortened. After the assembly of 6, the feed lines 5, 5 can be connected from the front side of the high-frequency electrodes 6, 6, so that the workability of connecting the feed lines 5, 5 to the high-frequency electrodes 6, 6 can be improved. Further, it is easy to visually check and retighten the connection state of the power supply lines 5 and 5, and a power supply structure with good maintainability can be obtained.

  While the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made based on the technical idea of the present invention.

1 is a schematic sectional view showing a plasma CVD apparatus according to a first embodiment of the present invention. It is a schematic sectional drawing which shows the plasma CVD apparatus which concerns on 2nd Embodiment of this invention. The plasma CVD apparatus which concerns on 3rd Embodiment of this invention is shown, (A) is a schematic sectional drawing (figure corresponding to FIG. 1), (B) is the Y section enlarged view in (A). It is a schematic sectional drawing which shows the plasma CVD apparatus which concerns on 4th Embodiment of this invention. It is a schematic diagram which shows the plasma processing apparatus by the capacitive coupling type parallel plate plasma CVD method which concerns on a prior art. It is the schematic diagram (the 1) of the plasma processing apparatus which shows the other example of arrangement | positioning relationship between the said high frequency electrode and feeder in the prior art. It is the schematic diagram (the 2) of the plasma processing apparatus which shows the other example of arrangement | positioning relationship between the high frequency electrode and feeder in the prior art. It is the schematic diagram (the 3) of the plasma processing apparatus which shows the other example of the arrangement | positioning relationship between the said high frequency electrode and feeder in the prior art. It is the schematic diagram (the 4) of the plasma processing apparatus which shows the other example of arrangement | positioning relationship between the said high frequency electrode and feeder in the prior art. It is a schematic sectional drawing which shows the plasma processing apparatus by the capacitive coupling type parallel plate plasma CVD method which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma CVD apparatus 2 Vacuum container 2a Vacuum chamber 3 High frequency power supply 4 Matching circuit 5 Feed line 51 Electrode connection side feed line 52 Main feed line 53 Feed flange connection side feed line 54 Feed flange 6 High frequency electrode 61 Square groove part (electrode back side)
62 Square groove (electrode front side)
7 Ground electrode 8 Substrate 9 Outer conductor 91 Spacing piece 10 Cooling water passage 11 Electrode connection flange 11a Square flange 11b Guide pin 11c Flange 11e Tightening screw

Claims (5)

  By providing a high-frequency electrode and a ground electrode arranged to face the substrate in the vacuum vessel, and applying a voltage and flowing a gas between the high-frequency electrode and the ground electrode by high-frequency power supply from a high-frequency power source through a power supply line In the plasma processing apparatus that generates plasma and performs plasma processing such as film formation and etching on the surface of the substrate, the feeder line has a large cross-sectional area on the high-frequency power source connection side on the upstream side, A power supply structure for a plasma processing apparatus, wherein a cross-sectional area on the high-frequency electrode connection side is smaller than a cross-sectional area on the high-frequency power source connection side.   The power supply line includes a power supply flange connected to the high frequency power supply side, a power supply flange connection side power supply line connected to the downstream side of the power supply flange, an electrode connection side power supply line connected to the high frequency electrode, The power supply flange connection side power supply line and the main power supply line that connects the electrode connection side power supply line, and the surface area of the electrode connection side power supply line is equal to or larger than the surface area of the main power supply line, The power supply structure of the plasma processing apparatus according to claim 1.   2. The plasma processing apparatus according to claim 1, wherein a cooling water flow path through which cooling water for cooling the power supply line flows is provided in a power supply flange attached to the vacuum vessel on the upstream side of the power supply line. Feeding structure.   A guide pin into which a square flange having a guide pin is provided at the end of the high-frequency electrode on the downstream side of the power supply line and embedded in a square groove provided on the back side of the high-frequency electrode, and the guide pin can be inserted. An electrode connection flange portion having a guide pin type connecting structure in which the high frequency electrode is sandwiched between the flange having an insertion hole and the square flange so that the power supply line and the electrode can be connected from the front side of the high frequency electrode The power supply structure for a plasma processing apparatus according to claim 1, comprising:   In the plasma CVD apparatus provided with a plurality of high-frequency electrodes and a plurality of ground electrodes, an electrode connection flange portion composed of the guide pin type connection structure of the power supply line is disposed in a space between the plurality of high-frequency electrodes. The power supply structure of the plasma processing apparatus according to claim 4.

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