JP5040067B2 - Film forming apparatus and film forming method - Google Patents

Description

  The present invention relates to a plasma CVD film forming apparatus (hereinafter referred to as a film forming apparatus) and a plasma CVD film forming method (hereinafter referred to as a film forming method), and in particular, uniformly on a long substrate surface under reduced pressure. The present invention relates to a film forming apparatus and a film forming method for stably and continuously forming a thin film.

  Conventionally, in order to form a thin film on a substrate by plasma CVD, a method using capacitively coupled plasma and inductively coupled plasma is known (Non-Patent Document 1).

Plasma Electronics Ohmsha, edited by Hideo Sakurai, 1st edition, 1st edition, issued on August 25, 2000, page 106

  On page 106, line 8 of this document, it is described that capacitively coupled plasma can easily generate large-diameter plasma, which can be applied to substrates such as ceramics such as wafers and glass, resin plates, plastic films, metal plates, and metal foils. On the other hand, capacitively coupled plasma is widely used in the field of thin film formation.

In FIG. 6.3 and page 106 of this document, the 13th to 14th lines use two electrodes for plasma discharge when capacitively coupled plasma is used for thin film formation. The film is formed in this state.
FIG. 8 shows an apparatus for forming a film by a capacitively coupled plasma CVD method that has a mechanism for continuously conveying a base material to a roll-shaped base material (Patent Document 1).

JP-A-11-61416

However, when the film is formed by such a method, the electrical flow of the plasma is difficult due to the arrangement of the semiconductor or insulating film-forming substrate, that is, the discharge impedance is increased, and the plasma discharge is difficult to occur. There was a problem that the stability of discharge deteriorated.
Instability of plasma discharge causes abnormal discharge such as arcing, and causes arcing traces with a diameter of several millimeters on the base material, and if this is severe, it causes poor appearance and quality degradation. There was a problem.
In addition, if the plasma is unstable, when forming a film on a long substrate or the like, the substrate conveyance control is also affected, and it is impossible to form a film continuously for a long time. there were.

Further, when the discharge impedance increases, the discharge voltage increases and the discharge current decreases even when the same power is applied. As a result, film formation rate decreases (productivity decrease), film stress increases, damage to the substrate (electric charge-up occurs, poor adhesion due to strong etching of the substrate, substrate coloring occurs Etc.), and deterioration of film quality becomes a problem.
Furthermore, since the discharge impedance differs depending on the base material, there arises a problem that the film thickness and film quality of the formed film differ, and it is necessary to optimize the film forming conditions for each type of base material.

The above problem is that, for example, when an insulating film such as SiO2 or TiO2 is formed, the discharge impedance is further increased due to poor decomposability of the film forming material, and the film forming becomes unstable. There is.
On the other hand, there may be a problem that the film forming impedance is small. When the discharge impedance is small, the discharge voltage is small, the discharge current is large, the effect of ion implantation into the substrate is small, and as a result, the adhesion of the film is insufficient, and film peeling may occur.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to form a film forming apparatus capable of stably forming a uniform thin film on the surface of a base material continuously with a long base material. And providing a film forming method.

In order to achieve the above-described object, a first invention is a film forming apparatus for forming a thin film on a base material under reduced pressure by a plasma CVD method, the chamber being provided in the chamber, A winding drum, a transport mechanism that transports the base material, a gas supply unit that supplies gas into the chamber, and the chamber is disposed on the same surface side of the base material and is electrically floating. A pair of electrodes, and a power source that supplies AC power having a frequency of 10 Hz to 27.12 MHz so that one electrode and the other electrode have opposite polarities between the two electrodes. The film forming apparatus is characterized in that plasma is generated between the pair of electrodes.

  Here, the electrical floating level means that the electrodes are designed and installed using insulating parts and insulating coatings so that insulation from the chamber and other film forming equipment parts installed at the earth level is maintained. It means the state that is. Despite being designed so that the insulation of the electrode is ensured, a refrigerant or heat medium necessary for cooling or heating the drum is used, and some piping for circulating and supplying this refrigerant or heat medium is used. The case where the electrode has a resistance of 10 kΩ to 1000 MΩ on the basis of the ground level (ground level) due to having the conductivity of 10 kΩ to 1000 MΩ is also included in the present invention.

  The electrode may include a magnet that concentrates and forms plasma near the substrate. The magnet preferably has a horizontal magnetic flux density on the substrate surface of 10 to 10,000 gauss. The magnet has a magnetron structure.

The power supply preferably has a frequency of 10 kHz to 27.12 MHz. The power source is subjected to input power control or impedance control.
The drum may be installed electrically at a ground level or may be installed electrically at a floating level. Further, when the drum is at a floating level, a constant DC voltage may be applied to the drum.

The gas supply unit is attached to the electrode side of the substrate and supplies gas toward the substrate surface. The gas supply unit may be at an electrically floating level.
The chamber may include a film forming chamber and a substrate transfer chamber. In order to form a film having sufficient film density and adhesion to the substrate, it is desirable to set and maintain the film formation pressure in the film formation chamber between 0.1 Pa and 100 Pa. The degree of vacuum in the base material transfer chamber prevents the film formation chamber plasma from leaking into the base material transfer chamber and makes the plasma discharge (film formation) unstable, and makes it possible to appropriately control the base material transfer. Therefore, in order to protect from the plasma damage to the substrate transport mechanism, it is desirable to set and maintain the vacuum degree in the range of 10 to 10,000 times higher than the degree of vacuum at the time of film formation in the film forming chamber. .

  You may provide the base-material charge removal part which removes the base-material charge which generate | occur | produced by film-forming in the said base-material conveyance chamber of the back | latter stage from the said film-forming chamber with respect to the surface of the single side | surface or both surfaces of a base material. The base material charge removal unit is a plasma discharge device or the like. A plasma discharge device may be provided in the base material transfer chamber upstream of the film formation chamber.

The chamber may have a film formation chamber and an exhaust chamber. It is desirable that the degree of vacuum in the exhaust chamber is in the range of 10 times to 10,000 times less than the degree of vacuum at the time of film formation in the film forming chamber.
By setting the degree of vacuum in the exhaust chamber in this way, by-products generated on the surface of the film forming substrate can be efficiently removed, and a high-quality film can be generated.
The drum is preferably made of a material containing at least one of stainless steel, iron, copper, and chromium, and the drum preferably has a surface average roughness Ra of 0.1 nm to 10 nm.

  You may further provide the temperature adjustment means which maintains the said drum at the fixed temperature between -20 degreeC and 200 degreeC. The drum may include an insulating region at both ends. The insulating region is formed of one or more oxide films, nitride films, or oxynitride films of Al, Si, Ta, Ti, Nb, V, Bi, Y, W, Mo, Zr, and Hf. Alternatively, the insulating region is covered with a molded body of any one of polyimide resin, fluororesin, and mica, a tape, and a coating film.

A second invention is a film forming method for forming a thin film on a base material under reduced pressure by a plasma CVD method. The base material is wound around a drum provided in the chamber, and gas is supplied into the chamber. In the chamber , the frequency is 10 Hz to be arranged between the pair of electrodes on the same surface side of the substrate and electrically floating level so that one electrode and the other electrode have opposite polarities. 27. A film forming method characterized in that an alternating current power of 27.12 MHz is supplied, plasma is generated between the pair of electrodes, and a thin film is formed on the substrate.

  According to the present invention, since the base material is not placed between the electrodes to form a film, it is not electrically coupled during plasma discharge, and it is possible to prevent an increase in discharge impedance. As a result, there are advantages such that plasma discharge is easily generated by reducing the discharge start voltage, and plasma discharge can be stably performed by reducing the discharge sustain voltage. In addition, since the discharge impedance is reduced, in plasma CVD film formation, film formation speed is improved (productivity improvement), film stress is reduced, and damage to the substrate is reduced (electric charge-up is suppressed, substrate etching is performed). It is possible to improve adhesion and reduce base material coloring.

Furthermore, since it is not necessary to consider the impedance variation due to the substrate, it is not necessary to optimize the film forming conditions for each type of substrate.
Moreover, it becomes possible to adjust the magnitude | size of an impedance as needed with the arrangement | positioning and shape of an electrode. Although the malfunction when discharge impedance becomes large previously was demonstrated, it may become a problem that film-forming impedance is small on the other hand. When the discharge impedance is small, the discharge voltage is small, the discharge current is large, the effect of ion implantation into the substrate is small, and as a result, the adhesion of the film is insufficient, and film peeling may occur.

  In such a case, specifically, the discharge impedance increases by increasing the distance between the electrodes installed in a set. As a result, when the applied power is constant, the discharge voltage for film formation is large and the discharge current is small. As a result, the ion implantation effect is enhanced, and a film with high adhesion can be formed.

  Conversely, by reducing the distance between the electrodes installed in pairs, the discharge impedance decreases. When the applied power is constant, the discharge voltage is small, the discharge current is large, and the deposition rate is increased (productivity Improvement), reduction of film stress, reduction of damage to the base material (inhibition of occurrence of electrical charge-up, improvement of adhesion due to reduction of base material etching, reduction of base material coloring).

  In this way, it is possible to optimize the discharge impedance, adjust the ion implantation effect on the base material, improve the adhesion of the film, reduce the damage to the base material, and can form a good film It becomes.

Hereinafter, a film forming apparatus and a film forming method according to an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of a film forming apparatus 1 according to an embodiment of the present invention. Partition walls 5 and 7 are formed in the chamber 3. A base material transfer chamber 9 is formed above the partition wall 5, a film formation chamber 11 is formed in a space surrounded by the partition wall 5 and the partition wall 7, and an exhaust chamber 13 is formed below the partition wall 7.

  An unwinding roller 15 and a winding roller 17 are provided in the base material transfer chamber 9. A drum 19 is provided so as to be sandwiched between the partition walls 5, and guide rollers 21-1, 21-2, 21-3 and a tension pickup roll 23-1 are provided between the unwinding roller 15 and the drum 19. Guide rollers 21-4, 21-5, 21-6 and tension pick-up rolls 23-2 are provided between the roller and the take-up roller 17.

  The unwinding roller 15 winds the base material 16, and the base material 16 is wound around the drum 19 via the guide rollers 21-1, 21-2, the tension pickup roll 23-1, and the guide roller 21-3. Further, the film is taken up by the take-up roller 17 through the guide roller 21-4, the tension pickup roll 23-2, and the guide rollers 21-5 and 21-6. The tension of the base material 16 is adjusted by the tension pick-up rolls 23-1 and 23-2, and the base material is conveyed.

Further, in FIG. 1, the base material transport direction is described so that the base material advances from the unwinding roller 15 to the take-up roller 17; however, film formation or base material processing is performed while transporting the base material in the reverse direction. It is also possible to repeat these steps. From the viewpoint of productivity and film quality, it is preferable to repeatedly form a film without returning the vacuum to atmospheric pressure.
The substrate 16 is a ceramic such as glass, a resin plate, a plastic film, a metal plate, a metal foil, paper, a nonwoven fabric, a fiber, or the like.

  A pre-processing device 25 and a post-processing device 27 are provided in the vicinity of the drum 19. The pretreatment device 25 is, for example, a plasma discharge device, and the posttreatment device 27 is a device that removes the base material charge generated by film formation, and is, for example, a plasma discharge device.

Gas supply units 37-1, 37-2, 37-3 are provided so as to be sandwiched between the partition walls 7, and the gas supply units 37-1, 37-2, 37-3 are provided as flow rate controllers 35-1, 35-. 2 and 35-3 are connected to the gas reservoirs 33-1, 33-2, 33-3.
The gas storage units 33-1, 33-2, and 33-3 store a film forming gas. For example, TEOS (tetraethoxysilane Si (OC ₂ H ₅ ) ₄ ), which is a film forming raw material, is decomposable. Oxygen (O ₂ ) that is an oxidizing gas and argon (Ar) that is an ionizing gas for discharge are stored. The flow controllers 35-1 and 35-2 measure the flow rate of the gas 35-3 sent from the gas storage units 33-1, 33-2 and 33-3 to the gas supply unit 37.

  The gas supply ports 37-1, 37-2, and 37-3 are directed toward the base material 16 on the drum 19 at the ejection ports. For this reason, the film forming gas can be uniformly diffused and supplied to the surface of the base material 16, and uniform film formation can be performed on a large area portion of the base material 16.

  An electrode unit 39-1 including an electrode 55-1 is provided between the gas supply units 37-1 and 37-2, and an electrode including the electrode 55-2 is provided between the gas supply units 37-2 and 37-3. A unit 39-2 is provided, and the electrodes 55-1 and 55-2 are connected to the power source 41, and power is supplied from the power source 41. Electrodes 55-1 and 55-2 are electrically set at a floating level.

  Here, the electrical floating level refers to the state in which the electrodes are designed and installed using insulating parts and insulating coatings so that insulation is maintained from chambers and film deposition equipment parts installed at the ground level. Means. Despite being designed so that the insulation of the electrode is ensured, the refrigerant necessary for cooling the electrode is used, and this refrigerant and the piping for circulating and supplying these refrigerants have some conductivity. The present invention also includes a case where a resistance of 10 kΩ to 1000 MΩ is provided between the electrode and the ground with reference to the ground level (ground level).

The substrate transfer chamber 9 is provided with a vacuum exhaust pump 31-1 via a pressure adjustment valve 29-1, and the film formation chamber 11 is provided with a vacuum exhaust pump 31-2 via a pressure adjustment valve 29-2. The exhaust chamber 13 is provided with a vacuum exhaust pump 31-3 through a pressure adjustment valve 29-3.
By adjusting the exhaust capability of these vacuum exhaust pumps and the opening of the pressure adjusting valve, it is possible to set an arbitrary degree of vacuum.

2 is a cross-sectional view of the electrode unit 39-1, FIG. 3 is a view taken in the direction of the arrow A in FIG. 2, and FIG. 4 is a cross-sectional view taken along the line CC in FIG.
An insulating shield plate 53 is provided on the support base 51, and an electrode 55 is provided on the insulating shield plate 53. In order to prevent heat conduction between these, a space may be provided by using an O-ring or a spacer to prevent direct contact. In any case, the electrode 55 has a structure that is electrically insulated from the support base 51. The electrode 55 is provided with a power supply wiring 59 whose exterior is covered with an insulating material, and a temperature control medium pipe 57 for circulating the refrigerant is provided inside the electrode 55.

  The same structure can be used for the electrode unit 39-2. In general, it is preferable to use the same size and the same structure for the electrode unit and the electrode used as a set in order to make the balance electrically equivalent.

  The power supply wiring 59 is connected to the power supply 41, and plasma 43 is generated from the electrode 55 when power is supplied from the power supply 41. The temperature adjusting medium flows inside the temperature adjusting medium pipe 57, and the electrode 55 and the electrode unit 39 can be cooled or heated.

  5 is a side view of the drum 19, FIG. 6 is a cross-sectional view of the drum 19, and FIG. 7 is a view in the direction of arrow D in FIG. 5. The drum 19 includes rotating shafts 63 at both ends of a cylindrical drum body 61. A bearing 65 is provided on the rotating shaft 63. In order to control the drum temperature, a pipe for circulating a temperature adjusting medium such as a refrigerant or a heat medium is installed inside the drum 19 and the rotating shaft 63. The drum can be adjusted to a constant temperature between −20 ° C. and + 200 ° C. by adjusting the temperature of the temperature adjusting medium circulating in the drum, and the temperature controllability is set temperature ± 2 ° C. It is preferable. Electrical insulating portions 69 are provided on both sides of the center portion of the drum body 61 and around the rotation shaft 63, and the base material 16 is wound around the center portion of the drum body 61.

The power supply 41 has a frequency of 10 Hz to 27.12 MHz. Stable film-forming discharge can be performed at a frequency of 10 Hz or higher, and at a frequency higher than 27.12 MHz, the power supply and its matching circuit become expensive and the apparatus cost increases.
More preferably, 10 kHz to 500 kHz, 13.56 MHz, and 27.12 MHz are preferable.

  When a film forming power source of 10 kHz to 500 kHz is used, the film forming material has a high efficiency for causing decomposition necessary for film forming and a high film forming material driving effect on the base material 16, so that a high quality film is obtained. Is obtained. Further, 13.56 MHz and 27.12 MHz further increase the decomposition efficiency for causing the decomposition necessary for film formation of the film forming material, increase the gas reactivity, and enable high-quality film formation with high density and high adhesion. . Since these power supplies are frequencies that are allowed to be used industrially even in the high frequency band, there are advantages that many such power supplies are commercially available and are inexpensive.

  As a control method of the power source 41, there is an impedance control method in which the input impedance control or the discharge impedance indicating the difficulty of the flow of electricity obtained by dividing the discharge voltage value by the discharge current value is controlled. In the input power control, the film formation can be performed stably, simply, and inexpensively by performing the film formation while stabilizing the plasma discharge so that the film formation input power of the power source 41 becomes constant.

  In the impedance control, when the response is fast and the impedance changes in the film formation for a long time, the composition of the CVD film forming gas changes due to the influence of moisture that starts to be released when the inner wall of the chamber 3 is warmed by discharge, for example. When the impedance changes as a result, there is an effect of maintaining this constant.

  Further, as a control method for stable film formation of the power supply 41, an optical method may be used. For example, a plasma emission monitor may be installed, the emission intensity of a specific element in the plasma may be monitored, and process control for making the emission intensity constant may be performed. In this case, as a process control method, the amount of supply gas such as a film forming source gas, a decomposable gas, an oxidizing gas, a discharge gas and an ionized gas is controlled, and film forming conditions such as a film forming pressure and a substrate temperature are controlled. May be.

  The drum 19 may be installed at an electrical ground level. When the drum 19 is installed at the ground level, the charged charges accumulated on the surface of the substrate 16 are released to the ground level, and as a result, stable film formation is possible. In this case, it can be realized by using a metal conductive material for the drum body, the rotating shaft, the bearing, and the drum support.

  Further, the drum 19 may be placed at an electrically floating level, that is, an insulation potential. By setting the potential of the drum 19 to the floating level, it is possible to prevent power leakage, to increase the deposition input power, and to increase the efficiency of use for the deposition.

Here, the electric floating level means a state in which the apparatus is designed and configured so as to be electrically insulated from the chamber 3 and apparatus parts. When a temperature control medium necessary for cooling and heating the drum 19 and the base material 16 is used even though the insulating property is ensured, for example, the pipe and the medium have some conductivity. It may have a resistance of 10 kΩ to 1000 MΩ on the basis of the ground level (ground level) due to having.
In this case, it can be realized by using any one or more of the drum rotation shaft, the bearing, and the drum support member as an insulating component.

  When the drum 19 is at an electrically floating level, it is possible to install a mechanism that applies a DC potential to the drum 19 to increase or weaken the effect of ionized film forming material on the substrate 16. In order to enhance the ionization implantation effect, it is preferable to apply a minus potential of minus 10 V to minus 3000 V to the base material 16, and in order to weaken the ionization implantation effect, a plus potential of plus 10 V to plus 3000 V is preferably imparted to the substrate 16. . Moreover, although it is expensive in terms of equipment, AC power having a frequency of 10 Hz to 27.12 MHz may be applied to the base material 16.

Further, in order to optimize the film forming impedance, it is possible to adjust the distance by changing the distance between the electrode 55-1 and the electrode 55-2. Specifically, when the distance between the electrode 55-1 and the electrode 55-2 is increased, the film formation impedance increases. When the film formation power is constant, the film formation discharge voltage is high and the film formation discharge current is small. Become. On the other hand, by reducing the distance between the two electrodes, the film formation impedance decreases, and when the film formation power is constant, the film formation discharge voltage is low and the film formation discharge current is large.
By such adjustment, it is possible to adjust the ion implantation effect on the base material, reduce damage to the base material, and conversely increase the adhesion rate of the film to the base material.

  The gas supply units 37-1, 37-2, 37-3 may be electrically floating. In this case, it is possible to prevent the deposition power from leaking to the gas supply units 37-1, 37-2, and 37-3, to increase the deposition input power, and the utilization efficiency for the deposition is also high. It will be a thing. In addition, it is possible to avoid film formation at the pipe supply port before the gas is supplied into the chamber 3 in the gas supply units 37-1, 37-2, and 37-3, and blocking the supply port.

  The substrate transfer chamber 9 is partitioned by a partition wall (zone seal) 5 and has a different pressure from the film forming chamber 11 where the electrodes 55-1 and 55-2 exist. By making the base material transfer chamber 9 and the film formation chamber 11 different spaces in pressure, the plasma 43 in the film formation chamber 11 leaks into the base material transfer chamber 9 and the plasma discharge state of the film formation chamber 11 becomes unstable. No damage to the members of the substrate transfer chamber 9 or electrical damage to the electric circuit for controlling the substrate transfer mechanism, causing poor control and stable film formation and substrate transfer. It becomes possible.

  Specifically, the film formation pressure in the film formation chamber 11 is between 0.1 Pa and 100 Pa. By performing film formation at such a film formation pressure, a stable plasma 43 can be formed.

  Then, the pressure (degree of vacuum) in the base material transfer chamber 9 is set to 10 to 10,000 times higher than the pressure (degree of vacuum) at the time of film formation in the film formation chamber 11. Thus, by setting the pressure in the substrate transfer chamber 9, the plasma 43 in the film forming chamber 11 does not leak into the substrate transfer chamber 9, and plasma CVD film formation in the film forming chamber 11 is stabilized. It can be carried out.

  The exhaust chamber 13 is partitioned from the film forming chamber 11 by a partition wall (zone seal) 7 and has a different pressure. The exhaust chamber 13 has a pressure (degree of vacuum) that is not less than 10 times and not more than 10000 times the pressure at the time of film formation in the film formation chamber 11. By partitioning the film formation chamber 11 and the exhaust chamber 13 and providing a pressure difference between the film formation chamber 11 and the exhaust chamber 13, the by-product generated during the film formation can be efficiently exhausted from the vicinity of the surface of the substrate 16. it can.

  A post-treatment device 27 is provided as a base material charge removing unit for removing the base material charge generated by film formation in the base material transfer chamber 9 subsequent to the film formation chamber 11.

  The post-processing device 27 is installed in the base material transfer chamber 9 subsequent to the film forming chamber 11, and by removing the base material charge, the base material 16 can be quickly separated from the drum 19 at a predetermined position and transferred. It becomes possible to convey the material, prevent damage to the base material 16 and deterioration of the quality due to charging, and improve post-processing appropriateness by improving the wettability of the front and back surfaces of the base material 16.

  As the post-processing device 27 serving as a charge removal unit, for example, an arbitrary processing device such as a plasma discharge device, an electron beam irradiation device, an ultraviolet irradiation device, a static elimination bar, a glow discharge device, or a corona treatment device can be used.

  When a discharge is formed using a plasma processing apparatus or a glow discharge apparatus, a discharge gas such as argon, oxygen, nitrogen, helium or the like is supplied in the vicinity of the substrate 16 as a single substance or a mixture, and alternating current (AC) plasma, direct current ( Any discharge method such as DC) plasma, arc discharge, microwave, surface wave plasma, etc. can be used. In a reduced pressure environment, a charging method using a plasma discharge device is most preferable.

  A pretreatment device 25 is provided in the base material transfer chamber 9 before the film forming chamber 11. The pretreatment device 25 is a plasma discharge treatment device, and this plasma discharge treatment device can physically etch the surface of the substrate 16 by subjecting the substrate 16 to plasma discharge treatment before film formation. In addition to being able to form a concavo-convex shape on the surface of the base material 16, it is possible to improve the adhesion of the film during subsequent film formation by changing the chemical bonding state or functional group.

  The drum 19 is formed of a material containing at least one of stainless steel, iron, copper, and chromium. The surface of the drum 19 may be subjected to a hard chrome hard coat treatment or the like to prevent scratches. Since these materials are easy to process and the thermal conductivity of the drum itself is good, the temperature controllability is excellent when performing temperature control.

  The drum 19 has a surface average roughness Ra of 10 nm or less, preferably 5 nm or less, and more preferably 2 nm or less. Usually, the average surface roughness Ra of the substrate 16 such as a plastic film or a metal plate (steel plate) or steel plate is usually 10 to 50 nm, 5 to 10 nm for the substrate 16 specially processed to have surface flatness, When flat processing is performed by surface coating processing, the drum 19 has a surface flatness of 5 nm or less. Therefore, in order to efficiently adjust the temperature of the base material 16 such as cooling and heating, the drum 19 has the above range. preferable.

Further, the surface of the drum 19 is preferably as flat as possible, but the limit of flatness measurement accuracy is currently 0.1 nm, and this value is set as the lower limit for convenience.
The drum 19 has a temperature adjustment mechanism that can be set to a constant temperature between −20 ° C. and + 200 ° C. by using a cooling medium and / or a heat source medium or a heater.

  The temperature adjustment mechanism can suppress fluctuations in the temperature of the base material 16 due to heat generated during film formation. Specifically, ethylene glycol aqueous solution is used as the cooling medium (refrigerant), silicon oil is used as the heat source medium (heating medium), the temperature is adjusted by circulating in the drum 19, and the heater is placed at a position facing the drum 19. It is possible to install.

  In particular, in the film forming apparatus 1, it is preferable that the set temperature can be set to a constant temperature between −20 ° C. and + 200 ° C. from the viewpoint of heat resistance restrictions of related mechanical parts and versatility. In the process using, it is preferable to control the temperature within a range of set temperature ± 2 ° C.

  As shown in FIGS. 5, 6, and 7, the drum 19 has an insulating portion 69 that is not covered with the base material 16 in the width direction of the base material 16 and an insulating portion 69 on the side surface of the drum. By forming the insulating portion 69, there is no region where the conductive metal portion is exposed in the film formation chamber 11, and the plasma formed for film formation does not electrically drop on the drum 19, and the stable plasma 43 Can be formed.

  The insulating portion 69 is formed of one or more oxide films, nitride films, or oxynitride films of Al, Si, Ta, Ti, Nb, V, Bi, Y, W, Mo, Zr, and Hf. Alternatively, the insulating portion 69 is covered with any one of polyimide resin, fluororesin, and mica, a tape, and a coating film. Since these methods and materials have reliable insulation, heat resistance, plasma resistance, and excellent durability, they can be used stably over a long period of time.

  The electrodes 55-1 and 55-2 may have a structure including a magnet 85 as shown in FIGS. 8, 9, and 10 instead of those shown in FIGS.

8 is a side view of the electrodes 55-1 and 55-2, FIG. 9 is a view taken in the direction of arrow B in FIG. 8, and FIG. 10 is a cross-sectional view taken along the line CC in FIG.
In general, it is preferable to use the same size and the same structure for the electrode unit and the electrode used as a set in order to make the balance electrically equivalent.

  The electrodes 55-1 and 55-2 have a magnetron structure. As shown in FIGS. 8, 9, and 10, an insulating spacer 84 and a base plate 83 are provided in the magnet case 81, and a magnet 85 is provided on the base plate 83. An insulating shield plate 87 is provided on the magnet case 81, and an electrode 89 is attached to the insulating shield plate 87. Therefore, the magnet case 81 and the electrode 89 are electrically insulated, and even if the magnet case 81 is installed and fixed in the chamber 3, the electrode 89 can be brought to an electrically floating level. A power supply wiring 93 is connected to the electrode 89, and the power supply wiring 93 is connected to the power supply 41. Further, inside the electrode 89, a temperature control medium pipe 91 for cooling the electrode and the magnet is provided.

  The magnet 85 is provided so that the plasma from the electrode 89 is concentrated on the substrate 16. By providing the magnet 85, the reactivity in the vicinity of the surface of the substrate 16 is increased, and a high-quality film can be formed at a high speed.

The magnet 85 has a horizontal magnetic flux density of 10 gauss to 10000 gauss at the surface position of the substrate 16. If the horizontal magnetic flux density on the surface of the base material 16 is 10 gauss or more, the reactivity in the vicinity of the surface of the base material 16 can be sufficiently increased, and a high-quality film can be formed at high speed.

  On the other hand, an expensive magnet or a magnetic field generating mechanism is required to make the horizontal magnetic flux density on the surface of the base material 16 higher than 10,000 Gauss.

  The arrangement structure of the magnets 85 of the electrodes 89-1 and 89-2 is a magnetron structure. By adopting a magnetron structure, ions and electrons formed during plasma CVD film formation move according to this magnetron structure. For this reason, for example, when plasma CVD film formation is performed on the base material 16 having a large area of 300 mm □ or more, the above-mentioned electrons, ions, and decomposition products of the film formation material are spread over the entire surfaces of the electrodes 89-1 and 89-2. Is uniformly diffused, and uniform and stable film formation is possible even when the substrate 16 has a large area.

  In addition, there is no accumulation of thermionic electrons or ions locally on the electrode unit, such as electrodes and magnets, and the heat resistance of the components may be low. It is possible to suppress the occurrence of defects such as perforations and cracks.

The electrodes 89, 89-1, and 89-2 are electrically conductive for supplying electric power, have excellent plasma resistance, have heat resistance, have high cooling efficiency with cooling water (high thermal conductivity), and are non-magnetic. It is preferable to use a material excellent in workability as a material. Specifically, aluminum, copper, and stainless steel are preferably used.
The insulating shield plate 87 is preferably made of an insulating material having excellent plasma resistance, heat resistance, and workability. Specifically, a fluororesin and a polyimide resin are preferably used.

  Next, a schematic operation of the film forming apparatus 1 will be described. The gas for film formation is supplied from the gas storage units 33-1, 33-2, 33-3 to the gas supply units 37-1, 37-2, 37-3, and the gas supply units 37-1, 37-2, 37 are supplied. The film-forming gas is ejected from −3 toward the substrate 16.

  In addition, power is supplied from the power source 41 to the electrodes 89-1 and 89-2, plasma 43 is emitted from the electrodes 89-1 and 89-2 toward the base material 16, and a thin film is formed on the base material 16. .

  According to the present invention, since the substrate is not deposited on the electrode and is not electrically coupled, an increase in the impedance of plasma discharge can be prevented, plasma can be easily formed, and a long time is required. It is possible to perform stable discharge and plasma CVD film formation. In addition, since the discharge impedance does not increase, in plasma CVD film formation, the film formation speed is improved (productivity improvement), film stress is reduced, and damage to the base material is reduced (electric charge-up is suppressed, base material etching is performed). It is possible to improve adhesion and reduce base material coloring by reduction.

Furthermore, since it is not necessary to consider the impedance fluctuation due to the substrate, it is not necessary to optimize the film forming conditions for each type of substrate.
Further, the size of the impedance can be adjusted as necessary depending on the arrangement and shape of the electrodes. Although the malfunction when discharge impedance becomes large previously was demonstrated, it may become a problem that film-forming impedance is small on the other hand. When the discharge impedance is small, the discharge voltage is small, the discharge current is large, the effect of ion implantation into the substrate is small, and as a result, the adhesion of the film is insufficient, and film peeling may occur. In such a case, specifically, the discharge impedance increases by increasing the distance between the electrodes 89-1 and 89-2 installed in pairs. As a result, when the applied power is constant, the discharge voltage for film formation is large and the discharge current is small. As a result, the ion implantation effect is enhanced, and a film with high adhesion can be formed.

  On the other hand, by reducing the distance between the electrodes 89-1 and 89-2, the discharge impedance decreases, and when the applied power is constant, the discharge voltage is small and the discharge current is large, improving the film formation rate (improving productivity). ), Reduction of film stress, and reduction of damage to the base material (suppression of occurrence of electrical charge-up, improvement of adhesion due to reduction of base material etching, reduction of base material coloring).

  In this way, it is possible to optimize the discharge impedance, adjust the ion implantation effect on the base material 16, increase the adhesion of the film, reduce the damage to the base material, and form a good quality film Is possible.

  Next, a description will be given of experimental results when films are actually formed using the film forming apparatus 1 shown in FIG. 1 and the film forming apparatus 201 as a comparative example shown in FIG.

  In the film forming apparatus 1 shown in FIG. 1, the electrodes 55-1 and 55-2 are set with the magnetron structure magnet 85 shown in FIGS. 8, 9, and 10 as described above, and the average horizontal surface on the surface of the substrate 16 is set. The magnetic flux density was set to 1000 gauss. The chamber 3 was set to the ground level, and the drum 19 was set to the floating level.

  A 30% concentration ethylene glycol aqueous solution was supplied as a refrigerant to the temperature control medium pipe 91. That is, the refrigerant was separately circulated and supplied to the drum 19 and the electrodes 55-1 and 55-2, and the drum 19 was cooled to 0 ° C. At this time, the resistance between the electrode 55-1 and the drum 19, between the electrode 55-2 and the drum 19, and between the electrode 55-1 and the electrode 55-2 was 1 MΩ.

A 0.6 m wide PET film (A4100, 100 μm thickness, manufactured by Toyobo Co., Ltd.) was prepared as the substrate 16 and set in the substrate conveyance system of the substrate conveyance chamber 9.
Both the film formation chamber 11 and the exhaust chamber 13 were evacuated to 1 × 10 ⁻⁴ Pa by the vacuum exhaust pumps 31-2 and 31-3. TEOS (tetraethoxysilane Si (OC ₂ H ₅ ) ₄ ) was vaporized at a heating temperature of 120 ° C. and supplied as a film forming gas. Then, TEOS, oxygen, and argon were supplied at 20 sccm, 500 sccm, and 200 sccm, respectively, and mixed uniformly, and then a gas was supplied onto the substrate 16 in a shower shape.

  Next, the vacuum exhaust pumps 31-1, 31-2, 31-3 are adjusted so that the pressure in the film forming chamber 11 is 10 Pa, and the pressure in the substrate transfer chamber 9 and the exhaust chamber 13 is a constant pressure of 0.5 Pa. It adjusted so that it might become. A power supply with a frequency of 40 kHz (PEII, 10 kW, manufactured by Advanced Energy Industries, Inc.) is used as the power supply 41, and 3 kW of power is applied to the electrodes 55-1 and 55-2 from the power control system, and the line speed is 5 m / min and 1200 m. Film formation was performed. In addition, after the start of film formation, an average discharge voltage was determined at the time of film formation 5 m before and after every film formation distance of 200 m. Further, as a result of visually counting the number of occurrences of discharge arcing (abnormal discharge), it was found that the occurrence was zero and there was no abnormal discharge, and stable film formation was possible.

  After film formation, the residual gas in the chamber 3 is exhausted, the base material 16 is taken out, visual observation of the surface of the base material 16 and sampling at the center of the base material width direction every 200 m, The density of the film was measured. The film thickness was determined from cross-sectional observation using a scanning electron microscope (SEM; manufactured by Hitachi, Ltd., S-5000H). The film density was calculated using an X-ray reflectivity measuring apparatus (manufactured by Rigaku Corporation, ATX-E) and attached software. FIG. 12 is a diagram showing a film formation result.

In contrast, a film forming apparatus 201 shown in FIG. 11 was prepared as a comparative example. Compared with the film forming apparatus 1 shown in FIG. 1, this film forming apparatus 201 has one side of the power supply 41 connected to the drum 19 and the electrodes 55-1 and 55-2 are electrically connected to the same potential. The resistance between the electrodes 55-1 and 55-2 was 0.1Ω. The film forming pressure was 0.5 Pa at all locations in the chamber 3.
Except for these, the film formation was performed by the same setting procedure as that of the apparatus shown in FIG. FIG. 13 is a diagram showing a film formation result.

  Comparing FIG. 12 and FIG. 13, in the film forming apparatus 1 according to the present invention shown in FIG. 1, the discharge voltage is reduced, the discharge is easily stabilized, and arcing during the discharge hardly occurs, and the quality is high and uniform. Can be formed. In addition, since the input electric power is effectively used for film formation, the film formation speed is improved, and a high-quality film having high film density, that is, high density is formed.

  The preferred embodiments of the information providing system and the like according to the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these naturally belong to the technical scope of the present invention. Understood.

The figure which shows the film-forming apparatus 1 which concerns on this Embodiment Cross section of electrode 39-1 A direction arrow view of FIG. CC sectional view of FIG. The figure which shows the drum 19 Cross section of drum 19 FIG. 5 arrow D direction view Cross section of electrode 39-1 A direction arrow view of FIG. CC sectional view of FIG. The figure which shows the film-forming apparatus 201 used as a comparative example The figure which shows the film-forming result by the film-forming apparatus 1 The figure which shows the film-forming result by the film-forming apparatus 201

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ......... Film formation apparatus 3 ......... Chambers 5, 7 ......... Partition wall 9 ......... Base material transfer chamber 11 ......... Deposition chamber 13 ......... Exhaust chamber 19 ......... Drum 25 ......... Previous Processing device 27... Post-processing device 37... Gas supply unit 39.

Claims (26)

A film forming apparatus for forming a thin film on a substrate under reduced pressure by a plasma CVD method,
A chamber;
A drum provided in the chamber and around which the substrate is wound;
A transport mechanism for transporting the substrate;
A gas supply unit for supplying gas into the chamber;
A set of electrodes disposed on the same surface side of the substrate in the chamber and electrically floating;
A power source for supplying AC power having a frequency of 10 Hz to 27.12 MHz so that one electrode and the other electrode have opposite polarities between the two electrodes;
Comprising
A film forming apparatus, wherein plasma is generated between the pair of electrodes.   The film forming apparatus according to claim 1, wherein the electrode includes a magnet that concentrates and forms plasma in the vicinity of the substrate.   The film forming apparatus according to claim 2, wherein the magnet has a horizontal magnetic flux density of 10 to 10,000 gauss on the substrate surface.   The film forming apparatus according to claim 2, wherein the magnet has a magnetron structure.   The film forming apparatus according to claim 1, wherein the power source has a frequency of 10 kHz to 27.12 MHz.   The film forming apparatus according to claim 1, wherein the power source is input power controlled.   The film forming apparatus according to claim 1, wherein the power source is impedance-controlled.   The film forming apparatus according to claim 1, wherein the drum is electrically installed at an earth level.   The film forming apparatus according to claim 1, wherein the drum is electrically installed at a floating level.   The film forming apparatus according to claim 1, wherein the gas supply unit is attached to the electrode side of the substrate and supplies gas toward the surface of the substrate.   The film forming apparatus according to claim 1, wherein the gas supply unit is electrically at a floating level.   The film forming apparatus according to claim 1, wherein the chamber includes a film forming chamber and a base material transfer chamber. The film forming apparatus according to claim 12, wherein a film forming pressure in the film forming chamber is between 0.1 Pa and 100 Pa. The film forming apparatus according to claim 12 , wherein the degree of vacuum in the substrate transfer chamber is 10 to 10,000 times higher than the degree of vacuum at the time of film formation in the film forming chamber. The film forming apparatus according to claim 12, further comprising a base material charge removing unit that removes base material charge generated by film formation in the base material transfer chamber downstream of the film forming chamber. The film forming apparatus according to claim 15, wherein the base material charge removing unit is a plasma discharge apparatus. The film forming apparatus according to claim 12 , wherein a plasma discharge device is provided in the base material transfer chamber upstream of the film forming chamber.   The film forming apparatus according to claim 1, wherein the chamber includes a film forming chamber and an exhaust chamber. 19. The film forming apparatus according to claim 18, wherein the degree of vacuum in the exhaust chamber is 10 to 10,000 times higher than the degree of vacuum in film formation in the film forming chamber.   The film forming apparatus according to claim 1, wherein the drum is formed of a material containing at least one of stainless steel, iron, copper, and chromium.   2. The film forming apparatus according to claim 1, wherein the drum has a surface average roughness Ra of not less than 0.1 nm and not more than 10 nm.   2. The film forming apparatus according to claim 1, further comprising temperature adjusting means for maintaining the drum at a constant temperature between −20 ° C. and 200 ° C.   The film forming apparatus according to claim 1, wherein the drum has electrically insulating regions at both ends. The insulating region is formed of one or more oxide films, nitride films, or oxynitride films of any one of Al, Si, Ta, Ti, Nb, V, Bi, Y, W, Mo, Zr, and Hf. 24. The film forming apparatus according to claim 23, wherein: 24. The film forming apparatus according to claim 23 , wherein the insulating region is covered with a molded body of any one of polyimide resin, fluororesin, and mica, a tape, and a coating film. A film forming method for forming a thin film on a substrate under reduced pressure by a plasma CVD method,
Wrap the substrate around the drum provided in the chamber,
Supplying gas into the chamber;
In the chamber , the frequency is 10 Hz to 27 so that one electrode and the other electrode have opposite polarities between a pair of electrodes that are disposed on the same surface side of the substrate and are in an electrically floating level. A film forming method comprising: supplying AC power of 12 MHz, generating plasma between the pair of electrodes, and forming a thin film on the substrate.

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