JP2008031521A - Roll-to-roll type plasma vacuum processing equipment - Google Patents

Abstract

A roll-to-roll type plasma vacuum processing apparatus is provided as a method for producing a vapor deposition tape, in which the quality of a DLC film as a protective film of a magnetic layer is uniform and mass production is possible.
In a capacitively coupled plasma CVD method in which a roll cathode electrode serving as a film forming stage of a substrate is a cathode, an opposing plasma injection reaction tube is an anode, and a high frequency is applied between both electrodes, plasma is applied. By configuring the electrode so that the anode area is larger than the opening area of the injection reaction tube, high-speed film formation can be performed on the substrate on the cathode by the asymmetric discharge effect of plasma. In addition to the vapor deposition tape, plasma can be generated without depending on the electric resistance of the base material. Therefore, plasma processing such as ion etching, ion ashing, and ion bombardment is possible in addition to plasma CVD.
[Selection] Figure 1

Description

  The present invention relates to a vacuum processing apparatus that performs processing on a long base material that is a material by roll-to-roll. More specifically, the present invention relates to a plasma vacuum processing apparatus in which a plasma injection reaction tube using a plasma jet is used in combination with a capacitively coupled plasma CVD method for applying a high-frequency voltage in order to form a protective film of a magnetic recording medium.

  In a magnetic recording medium having a metallic thin film as a magnetic layer, a hard protective film is usually provided on the metallic magnetic thin film in order to improve slidability with the magnetic recording head. For example, in the manufacturing process of a vapor deposition tape, a diamond-like carbon (hereinafter referred to as DLC) film is formed on the magnetic layer in order to increase the durability of the magnetic layer.

  As such a method, there is a method in which a DLC film is formed by a plasma CVD method using direct current glow discharge (see, for example, Patent Document 1). However, since the magnetic layer is used as a negative electrode and plasma is generated between the negative electrode and the positive electrode provided in the reaction tube, it is known that the film formation rate and film quality change when the resistance value of the magnetic layer varies depending on the thickness and oxidation degree of the magnetic layer. It has been. Moreover, vapor deposition tapes with high recording density that will be required in the future tend to have high resistance, and productivity tends to deteriorate.

  As a method of solving these problems, there is a method of applying high-frequency plasma that does not depend on the resistance of the magnetic layer. However, the method of applying high-frequency plasma is generally unsuitable as a method for manufacturing a vapor deposition tape that is required to be manufactured at a low cost because the film formation rate is lower than that of direct current glow discharge.

Accordingly, various methods have been devised to improve the method using high-frequency plasma and to mass-produce thin films with excellent uniformity of characteristics.
For example, there is a method of continuously forming a film while flowing in a long discharge space (see, for example, Patent Document 2). However, since the polymer film used for the magnetic recording medium is thin and weak to heat, there has been a drawback in that, when trying to obtain a high film formation rate, thermal deformation is caused by the radiant heat of plasma.

  In addition, there has been a method of using a roller-type electrode in order to increase the electrode area in the vacuum chamber (see, for example, Patent Document 3). However, since it is difficult to apply a bias only to the base material that always flows, a high frequency is applied to the main roller. In this case, there is a problem that a bias is applied to the entire main roller and the product adheres when there is a process gas in the vicinity.

In addition, in order to increase the deposition rate of the film, there has been a method of providing a gas supply port for locally increasing the gas pressure on the electrode surface and narrowing the distance between the electrodes (for example, see Patent Document 4). However, even if the shape of the gas supply port is devised, the gas pressure is not uniform over the wide electrode surface in the reaction vessel. In addition, it is more difficult to stably run a thin base material between narrow electrodes with uneven gas pressure.
JP 2000-17440 (page 3, FIG. 1) JP-A-11-135440 (5th page, FIG. 1) Japanese Patent Laid-Open No. 10-298774 (page 14, FIG. 35) JP-A-6-158331 (page 4, FIG. 5)

  As described above, the conventional method using high-frequency plasma has a low film formation rate and is not suitable as a method for manufacturing a vapor deposition tape manufactured at low cost. For this reason, various ideas were made, but none of them was sufficient. An object of the present invention is to provide a roll-to-roll type plasma CVD apparatus capable of producing a large amount of a DLC film as a protective film for a magnetic layer as a method for producing a vapor deposition tape.

  The above-mentioned subject has a roll type cathode electrode and a plasma injection type reaction tube, and sends out the base material from a roll base material in which a base material formed by forming a functional thin film on a long support is wound, A voltage is applied between the roll-type cathode electrode and the plasma injection reaction tube while the substrate is running along the peripheral surface of the roll-type cathode electrode, and reactants generated in the plasma injection reaction tube are removed. A vacuum processing apparatus that processes the functional thin film by colliding with the base material and winds the functional thin film into a roll, wherein the roll-type cathode electrode serving as a processing stage of the base material is used as a cathode, and the facing In a capacitively coupled vacuum processing system in which a plasma injection reaction tube is an anode and a high frequency is applied between both electrodes, the plasma injection Than the opening area of the emission reaction tube is solved by the plasma vacuum processing apparatus constituting the both electrodes as the surface area of the anode is increased.

  According to the present invention, it is possible to form a film on a base material on a roll-type cathode electrode at a high speed by using the asymmetric discharge effect of plasma.

  In addition, it is possible to provide a DLC film forming apparatus that does not depend on the resistance of the magnetic layer and is suitable for mass production of vapor deposition tape.

In addition, the plasma can be generated without depending on the electrical resistance of the substrate, not limited to the plasma-enhanced tape by plasma CVD. Therefore, H ₂ , He, Ar, Xe, silane, fluorine, chlorine, bromine Various plasma treatments such as ion etching, ion ashing, and ion bombardment are possible by supplying an organic metal solvent or the like or by mixing them. Therefore, it can be applied to various plasma vacuum processing apparatuses for producing products characterized by a flexible base material such as an optical compensation film, a light-emitting film typified by organic EL, a film-type solar cell, and a gas barrier film, in a roll-to-roll manner.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic diagram of a plasma CVD apparatus 1 according to an embodiment of the present invention. The base material 20 fed out from the unwinding roll 3 passes through the unwinding side guide roll 7, the roll-type cathode electrode 5 corresponding to the film forming stage, and the winding side guide roll 8, and is a vapor deposition that is a finished product. The tape 21 is wound around the winding roll 4. Four plasma injection reaction tubes 9 are arranged on the opposite surface of the roll type cathode electrode 5, and the process gas 22 is introduced only into the reaction tube, and the gap between the reaction tube 9 and the roll type cathode electrode 5 is adjusted. The pressure in each reaction tube 9 can be individually controlled.

  When the vapor-deposited tape 21 that is a magnetic recording medium is manufactured, the support 24 is a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, a polyolefin resin, a cellulose derivative such as cellulose triacetate, a polycarbonate resin, a polyvinyl chloride resin, Polymeric substances such as polyamide resin can be used.

  In addition, when a DLC film is formed as the protective film, a gas containing carbon is used as the process gas 22. Gasified from hydrocarbon gases such as methane, ethylene and butane, and organic solvents such as toluene and ketones can be used.

  FIG. 2 is a schematic diagram showing a process according to the embodiment of the present invention. As shown in FIG. 2, the plasma 30 can be created only in the reaction tube 9 by creating an electric field between the anode electrode 11 and the roll cathode electrode 5 disposed in the reaction tube 9. Furthermore, most of the hydrocarbon ions decomposed and positively ionized by the plasma 30 in the reaction tube 9 are deposited as the DLC film 26 on the base material 20 disposed on the roll cathode electrode 5 having a negative potential. Contamination in the vacuum chamber body 2 can be suppressed.

  Therefore, it can be said that the plasma injection reaction tube 9 is an optimum film formation source for roll-to-roll type continuous film formation. As a material of the anode electrode 11 used in the plasma injection reaction tube 9, a metal material such as stainless steel or copper can be considered. In addition, a metal material is not particularly required as long as it has a conductive property.

  The roll-type cathode electrode 5 has a structure in which the surface layer of a metal can described in JP-A-11-6071 is covered with an insulating layer made of ceramic, and arc discharge can be suppressed by blocking DC components.

  That is, as shown in FIG. 9, the roll-type cathode electrode 5 has a thickness in which an insulating layer 65 made of an insulating ceramic is 0.3 to 1.0 mm on the outer peripheral surface of a cylindrical metal can 62 made of stainless steel or the like. Is formed. The insulating layer 65 provided on the entire outer peripheral surface prevents plasma and positive ions from flowing through the roll-type cathode electrode 5 and suppresses abnormal discharge. The metal can 62 is formed with refrigerant passages 63 and 68 to 73 for preventing thermal deformation of the support 24 of the base material 20.

  The electric field applied between the electrodes is alternating current or pulse, and the frequency can be increased up to the upper limit at which power can be supplied to the parallel plate electrodes, but 50 Hz to 30 MHz is preferable in actual use. The gas pressure in the reaction tube 9 is closely related to the film forming rate and film quality, and is preferably 13 to 133 Pa in actual use.

  2 corresponds to a portion surrounded by a broken line P in FIG. When a process gas 22 is introduced into the reaction tube 9 and a high frequency is applied from the high frequency power source 16 between the anode electrode 11 and the roll-type cathode electrode 5 in the reaction tube 9, plasma 30 is generated. To do. Here, the DLC film 26 is formed on the magnetic layer 25 of the base material 20 that runs along the peripheral surface of the roll-type cathode electrode 5, thereby forming a vapor deposition tape 21 that is a finished product.

  Further, as shown in the schematic diagram of FIG. 2, a process gas 22 is introduced into the reaction tube 9, and a high frequency is provided between the anode electrode 11 and the roll-type cathode electrode 5 in the reaction tube 9. When plasma is applied, a plasma 30 is generated, and a sheath K31 and a sheath A32 are formed where the plasma 30 contacts each electrode surface.

This state can be expressed like the equivalent circuit of the embodiment of the present invention shown in FIG. If the electrode interval is about 30 mm and the pressure is about 30 Pa, it can be assumed that there is no potential gradient R _P in the plasma 30. Further, in the high frequency band of about 13.56 MHz, the resistance components R _K and R _A of the sheath K31 and the sheath A32 can be ignored. Incidentally, C _B is b - also serves as a blocking capacitor that blocks the DC component of the circuit is a capacitor component of the insulating layer 65 on the surface of the cathode electrode 5 - Le type cathode.

  Strictly speaking, the peripheral surface of the roll-type cathode electrode 5 has a curvature. However, since the roll-type cathode electrode 5 having a sufficiently large diameter with respect to the reaction tube 9 is used here, its peripheral surface is parallel to the opening of the reaction tube 9 when viewed macroscopically. Can be considered.

Under the above conditions, the self-bias voltage applied to each electrode is V _DC = (C _K -C _A ) / (C _K + C _A ) × V _RF
It can be simply expressed as: Since the sheath capacities C _K and C _A are capacitor components, they can be regarded as C = ε (dielectric constant) × s (electrode area) / g (sheath width), respectively. Capacity can be said to be proportional.

If the surface area of the anode electrode 11 and the cathode electrode 5 are the same, the resulting sheath width is g ₁ = g ₂ , so C _K = C _{A and} V _DC = 0, that is, the self-bias voltage Is symmetrical to both electrodes.

  The self-bias voltage is greatly related to the film forming rate, and by increasing the self-bias voltage on the cathode side corresponding to the substrate side, ion decomposition, acceleration, and deposition can be promoted (asymmetric discharge of plasma). effect).

From the above, in this equipment structure, in order to obtain a high film formation rate, it is effective to set C _K << C _A and increase the electrode area on the anode side so that V _DC = −V _RF is satisfied. It is.

  FIG. 4 shows an anode electrode 11 according to the embodiment of the present invention. In order to increase the electrode area exposed to the plasma 30 within the internal volume of the reaction tube 9 and to obtain a uniform film pressure, the plurality of metal plates 11a are arranged along the running direction of the substrate 20 and each metal plate 11a They are arranged in fins so as to be parallel to each other (hereinafter referred to as fins).

  Strictly speaking, since the peripheral surface of the roll-type cathode electrode 5 has a curvature, the traveling direction of the substrate 20 also has a curvature. However, since the roll-type cathode electrode 5 having a sufficiently large diameter is used with respect to the reaction tube 9, its peripheral surface is regarded as a parallel plate with respect to the opening of the reaction tube 9 when viewed macroscopically. Therefore, it can be considered that the traveling direction of the base material 20 is also straight.

Therefore, the plurality of fins 11 a are arranged along the traveling direction of the base material 20 so that the fins 11 a are parallel to each other, and can be regarded as being arranged perpendicular to the cathode electrode 5.
Since the surface areas of the side surfaces of the fins 11a are added, the anode electrode area can be increased.

  As for the anode electrode 11 which consists of the several fin 11a arrange | positioned perpendicularly | vertically with respect to the cathode electrode 5, as for the closest distance with the cathode electrode 5, 30-60 mm is desirable. Further, it is desirable that the distance between adjacent fins 11a is 20 to 40 mm sufficient to maintain the plasma 30. The process gas 22 passes from the bottom surface of the reaction tube 9 through the lower electrode portion 14 having a mesh structure, and is supplied between the anode electrode 11 and the cathode electrode 5.

7 and 8 show the results of forming the DLC film 26 on the base material 20 using the anode electrode 11 of the embodiment of the present invention. The total area of the anode electrode 11 was increased with respect to the opening area (that is, the cathode area) of the reaction tube 9 with the gas type, gas pressure, and input voltage V _RF as fixed conditions. FIG. 7 shows that the film formation rate increases as the area ratio increases. The asymmetric discharge effect of plasma was confirmed.

  Further, FIG. 8 shows that the film quality is improved by increasing the inorganic component in accordance with the increase in the area ratio. The organic component decreases and the inorganic component (diamond or graphite component) increases. This indicates that the ions hit against the base material 20 by the self-bias effect have an effect of further modifying the deposited DLC film 26.

  As described above, a roll-to-roll type plasma CVD apparatus 1 having a good quality of the DLC film 26 as the protective film 26 of the magnetic layer 25 and capable of mass production was obtained.

  As mentioned above, although embodiment of this invention was described, of course, this invention is not limited to these, A various change is possible based on the technical idea of this invention.

  For example, in consideration of the flow of the process gas 22, the anode electrode 12 (FIG. 5) in which the metal plates 12a are arranged in a lattice shape, and the anode electrode 13 (FIG. 6) in which the metal plates 13a are arranged in a honeycomb shape are further provided as electrodes. This is effective in increasing the area and improving the film formation rate.

In addition, not only vapor deposition tape but also plasma can be generated without depending on the electric resistance of the substrate, so that H ₂ , He, Ar, Xe, silane, fluorine, chlorine, bromine, organometallic Various plasma treatments such as plasma CVD, ion etching, ion ashing, and ion bombardment can be performed by supplying a system solvent or the like or by mixing them.

The ion etching is used for etching for forming an active element in a silicon layer as a functional thin film using, for example, NF ₃ .

In addition, ion ashing uses, for example, O ₂ and is used to remove a resist applied for functional thin film etching after etching.

The ion bombardment uses, for example, a mixed gas of Ar and H ₂ and is used for processing a base for forming a DLC film on a stainless steel support. This is because a DLC film may be used to protect the surface of a hard metal such as stainless steel, but since the bonding force with the hard metal is weak, it is necessary to perform a ground treatment. It is effective if the present invention is applied to these.

  In addition, the processing stage is the roll-type cathode electrode 5, but in the embodiment, it is a film forming stage because it is a process of forming a protective film on the substrate. On the other hand, ion etching, ion ashing, and ion bombardment are steps of removing substances from the surface of the substrate by the chemical and physical action of plasma, and thus are removal (peeling) stages.

  In the embodiment, a polymer material which is plastic is used for the support 24. However, any long tape-like material made of fiber, fabric (woven fabric / nonwoven fabric) or metal that can support a functional thin film can be used. it can.

  In the examples, the functional thin film is a metal thin film that becomes a magnetic layer. However, in order to form a film type solar cell, a light emitting film, an optical compensation film, a gas barrier film, etc., a metal oxide thin film or a ceramic thin film is used. Can be used.

1 is a schematic view of a plasma CVD apparatus 1 according to an embodiment of the present invention. The base material 20 fed out from the unwinding roll 3 passes through the unwinding side guide roll 7, the roll-type cathode electrode 5 corresponding to the film forming stage, and the winding side guide roll 8, and is a vapor deposition that is a finished product. The tape 21 is wound around the winding roll 4. In addition, the arrow in a figure represents the rotation direction 51 of a roll, and the moving direction 52 of a reaction tube. It is a schematic diagram of the plasma CVD apparatus by embodiment of this invention. This corresponds to a P portion surrounded by a broken line in FIG. In addition, the arrow in a figure represents the base material, the running direction 53 of a vapor deposition tape, and the flow 54 of process gas. FIG. 3 is an equivalent circuit diagram according to the embodiment of the present invention. The structure of the electric system of the schematic diagram shown in FIG. 2 is shown. It is a figure which shows the structure of the anode electrode by embodiment of this invention. (A) is a longitudinal cross-sectional view, (b) is an arrow view of the cross section taken along the alternate long and short dash line as viewed from the L direction in (a). The metal plates 11a are arranged in a fin shape. It is a figure which shows the modification of the anode electrode by embodiment of this invention. (A) is a longitudinal cross-sectional view, (b) is an arrow view of the cross section taken along the alternate long and short dash line as viewed from the M direction in (a). The metal plates 12a are arranged in a grid pattern. It is a figure which shows the other modification of the anode electrode by embodiment of this invention. (A) is a longitudinal cross-sectional view, (b) is an arrow view of the cross section taken along the alternate long and short dash line from (N) direction in (a). The metal plates 13a are arranged in a honeycomb shape. It is a graph of the film-forming rate which shows the film-forming result of the DLC film by embodiment of this invention. It was shown that the deposition rate increased as the anode area was larger than the cathode area. It is a graph of the film quality which shows the film-forming result of the DLC film by embodiment of this invention. It shows that the quality of the deposited DLC film is improved as the anode area is larger than the cathode area. It is a schematic diagram (longitudinal cross section) of the roll type cathode electrode 5 used for the plasma CVD apparatus by embodiment of this invention. In addition, the arrow in a figure represents the flow of a refrigerant | coolant.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Plasma CVD apparatus, 2 ... Vacuum chamber main body, 3 ... Unwinding roll, 4 ... Winding roll, 5 ... Roll type cathode electrode, 7 ... Unwinding side guide roll , 8 ... Winding side guide roll, 9 ... Reaction tube,
DESCRIPTION OF SYMBOLS 10 ... Process gas introduction pipe, 11 ... Anode electrode, 11a ... Metal plate (fin shape), 12 Anode electrode, 12a ... Metal plate (grid shape), 13 ... Anode electrode, 13a ... Metal plate (honeycomb), 14 ... Lower electrode part, 16 ... High frequency power supply ( _VRF ), 17 ... High frequency wiring, 18 ... Roll-shaped substrate (unwinding side), 19 ... Rolled vapor deposition tape (winding side)
20 ... base material, 21 ... vapor deposition tape, 22 ... process gas, 24 ... support, 25 ... magnetic layer (metal thin film), 26 ... DLC film (protective film),
30 ... plasma, 31 ... sheath K, 32 ... sheath A,
51 ... rotational direction, 52 ... moving direction, 53 ... moving direction, 54 ... gas flow, 55 ... refrigerant flow,
62 ... Metal can, 63 ... Refrigerant flow path, 64 ... Metal layer, 65 ... Insulating layer, 66 ... Rotation drive shaft, 67 ... Rotation follow-up shaft, 68 ... No. 1 refrigerant passage pipe, 69 ... partition walls of the first refrigerant passage, 70, 71 ... refrigerant passage, 72 ... second refrigerant passage pipe, 73 ... third refrigerant passage pipe,
A: Anode,
C _A ... Capacitance component of sheath A, C _B ... Capacitance equivalent to blocking capacitor, C _K ... Capacitance component of sheath K,
g... sheath width, g ₁ ... cathode side sheath width, g ₂ ... anode side sheath width,
K ... cathode,
R _A ... resistance component of sheath A, R _K ... resistance component of sheath K, R _P ... resistance component of plasma,
s ... Area of electrode

Claims (11)

A roll-type cathode electrode and a plasma injection-type reaction tube are provided, and the base material is fed out from a roll-shaped base material in which a base material formed by forming a functional thin film on a long support is wound. A voltage is applied between the roll cathode electrode and the plasma injection reaction tube while running along the peripheral surface of the roll cathode electrode, and a reaction product generated in the plasma injection reaction tube is applied to the substrate. A vacuum processing apparatus that processes the functional thin film by colliding it and winds the functional thin film into a roll, wherein the roll-type cathode electrode serving as a processing stage of the base material is used as a cathode, and the plasma injection-type reaction facing each other In a capacitively coupled vacuum processing system in which a tube is an anode and a high frequency is applied between both electrodes, the plasma injection reaction tube Plasma vacuum processing apparatus characterized by than the mouth area constituting the both electrodes as the surface area of the anode is increased. The plasma vacuum processing apparatus according to claim 1, wherein the support is one of plastic, fiber, cloth, and metal. The plasma vacuum processing apparatus according to claim 1, wherein the functional thin film is any one of a metal thin film, a metal oxide thin film, and a ceramic thin film. The electrode structure of the anode is configured in any one of a fin shape, a lattice shape, and a honeycomb shape arranged in parallel with a traveling direction of the base material. Plasma vacuum processing equipment. 5. The plasma vacuum according to claim 1, wherein any one of plasma CVD, ion etching, ion ashing, and ion bombardment can be performed by changing a kind of gas that is a material of the plasma. Processing equipment. 6. The plasma vacuum processing apparatus according to claim 5, wherein the treatment is used for producing any one of a vapor deposition tape, an optical compensation film, a light emitting film, a film type solar cell, and a gas barrier film. A plasma vacuum processing apparatus used for manufacturing the vapor deposition tape, wherein the plastic forming the long support is made of a polyester resin, a polyolefin resin, a cellulose derivative, a polycarbonate resin, a polyvinyl chloride resin, or a polyamide resin. It is either, The plasma vacuum processing apparatus of Claim 6 characterized by the above-mentioned. 7. The plasma vacuum processing apparatus according to claim 6, wherein the plasma vacuum processing apparatus is used for manufacturing the vapor deposition tape, and the functional thin film is a metal thin film that becomes a magnetic layer. The plasma vacuum processing apparatus according to claim 6, wherein a protective film is formed on the functional thin film by plasma CVD. The plasma vacuum processing apparatus used for manufacturing the vapor deposition tape, wherein the protective film formed on the functional thin film is a diamond-like carbon film. apparatus. 11. The plasma vacuum processing apparatus used for manufacturing the vapor deposition tape, wherein the gas used as a plasma material is one of hydrocarbon gas or gasified organic solvent. Plasma vacuum processing equipment.

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