JP2013037811A - Plasma processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma processing apparatus which reduces mixing of impurities into the process gas by suppressing or preventing inflow of the atmosphere gas into the processing space near the atmospheric pressure.SOLUTION: A processing space 90 is formed between a planar discharge surface 11a of a first electrode 11, and the peripheral surface of a cylindrical second electrode 21. A workpiece 9 is transported by rotating the second electrode 21 about the axis line. An outlet 30 of the process gas is arranged on one side of the first electrode 11. A shield member 50 is arranged on the other side of the first electrode 11. The shield member 50 is projected farther toward the second electrode 21 than the discharge surface 11a or the processing space definition surface of a solid dielectric layer 12 covering the discharge surface 11a, and the projection amount h is set larger than the thickness gat the narrowest portion 90a of the processing space 90.

Description

  The present invention relates to an apparatus for plasma-treating an object to be processed by making the process gas into plasma and bringing it into contact with the object to be processed, and in particular, plasma processing for generating a plasma discharge between a cylindrical electrode and a counter electrode near atmospheric pressure. Relates to the device.

  For example, the atmospheric pressure plasma processing apparatus described in Patent Document 1 includes a concave electrode and a cylindrical electrode. The concave electrode has a concave curved surface composed of a partially concave cylindrical surface. The concave curved surface and the outer peripheral surface of the cylindrical electrode face each other, and a processing space having a constant thickness is formed between the facing surfaces. At least one of these opposing surfaces is provided with a solid dielectric layer such as a sprayed film. The concave electrode is connected to a power source and serves as an electric field application electrode. The cylindrical electrode is electrically grounded and serves as a ground electrode. Further, a first skirt, an inert gas nozzle, a processing gas nozzle, the concave electrode, a suction nozzle, and a second skirt are sequentially arranged along the circumferential direction of the cylindrical electrode. A continuous sheet-like workpiece is wound around the outer peripheral surface of the cylindrical electrode, and the cylindrical electrode rotates around the axis, so that the workpiece is conveyed so as to pass through the processing space. Then, an electric field is applied between the concave electrode and the cylindrical electrode to generate an atmospheric pressure glow discharge, and a processing gas is introduced from the processing gas nozzle into the processing space to be turned into plasma. The plasma-ized processing gas contacts the object to be processed in the processing space, and the object to be processed is surface-treated. The treated gas is sucked into the suction nozzle. At the same time, an inert gas such as Ar is blown from the inert gas nozzle, and the pressure of the gap between the inert gas nozzle and the cylindrical electrode is made higher than the processing space, so that the processing gas flows to the opposite side of the processing space. Is preventing. Further, by setting the gaps between the first and second skirts and the cylindrical electrode to be narrower than the thickness of the processing space, the leakage of the processing gas from these gaps is prevented.

JP 2000-309870 A

In the plasma surface treatment of the workpiece, the process gas recipe management is important. In particular, in plasma processing near atmospheric pressure, atmospheric gases such as air are likely to be mixed into the processing gas. In particular, in recent years, there is a tendency to increase the conveyance speed of the object to be processed, and an atmospheric gas such as air tends to be caught in the processing space together with the object to be processed. Atmospheric gases such as air contain oxygen and water vapor, and if they are mixed in the processing gas, there is a risk that good surface treatment may be hindered.
An object of the present invention is to prevent the inflow of atmospheric gas into a processing space with a simple configuration and to perform surface treatment satisfactorily.

In order to solve the above problems, the present invention converts a processing gas into plasma (including excitation, decomposition, activation, radicalization, and ionization) by applying an electric field in a processing space near atmospheric pressure, and the processing space. In the plasma processing apparatus for plasma processing the surface of the processing object by bringing the processing gas into contact with the processing object passing through the inside,
A first electrode for applying the electric field having a planar discharge surface perpendicular to the first direction;
The processing space is formed between the first electrode and a cylindrical shape with an axis lined in a processing width direction orthogonal to the first direction, and the workpiece is rotated by rotating around the axis line. A second electrode to be conveyed;
A blow-out portion that is disposed on one side portion (first side) of the first electrode in the second direction perpendicular to both the first direction and the processing width direction, and introduces the processing gas into the processing space;
The second electrode is disposed on the other side (second side) of the first electrode in the second direction, and the discharge electrode or the surface defining the processing space of the solid dielectric layer covering the discharge surface. A shielding member projecting in the first direction toward
The projection amount of the shielding member is larger than the thickness of the narrowest part of the processing space.
As a result, the internal pressure of the processing space can be increased to suppress or prevent the atmospheric gas such as air from flowing into the processing space, and the amount of impurities mixed into the processing gas can be reduced to 0 to a very small amount. Therefore, a good surface treatment can be performed without being affected by the environment (the state of the atmospheric gas). Further, it is not necessary to provide a suction / exhaust mechanism for preventing the atmospheric gas from flowing in, and the apparatus configuration can be simplified. Furthermore, the structure of the first electrode can be simplified by making the discharge surface flat.

  The protruding amount of the shielding member is preferably 2 mm or more, and more preferably 3 mm or more. As a result, the inflow of atmospheric gas into the processing space can be more reliably suppressed or prevented. The upper limit of the protruding amount of the shielding member is set so that the protruding end of the shielding member does not hit the second electrode, and further, the gap between the protruding end of the shielding member and the second electrode is It is set to be larger than the thickness of the workpiece. Thereby, the workpiece can be passed through the gap.

  The conveyance speed of the workpiece is a high speed of about 20 m / min to 40 m / min, for example. For this reason, the effect of entraining atmospheric gas such as air is large. On the other hand, by providing the protrusions, the amount of atmospheric gas can be reliably suppressed, and the amount of impurities mixed into the processing gas can be reliably reduced. For example, in the wettability improvement process, the entrainment action by the high-speed conveyance and the entrainment suppression action by the protrusion can be combined to add a small amount of oxygen from the atmosphere to the processing gas such as nitrogen. , Wettability can be remarkably improved.

  It is preferable that the blow-out portion is disposed upstream of the first electrode in the conveyance direction of the workpiece. It is preferable that the shielding member is disposed downstream of the first electrode in the conveyance direction of the workpiece. This obstructs the flow of the processing gas on the downstream side of the processing space, so that the internal pressure of the processing space can be reliably higher than the surrounding environmental pressure. Therefore, the atmospheric gas inflow to the processing space can be reliably suppressed or prevented.

  It is preferable that the blowout part includes a blowout opening that opens toward the processing space. As a result, the processing gas can be directly introduced into the processing space from the outlet. The blowing portion has a protruding portion that protrudes in the first direction toward the second electrode from a surface that defines the processing space of the discharge surface or the solid dielectric layer, and the protrusion of the protruding portion It is preferable that the blow-out opening is opened on a side surface facing the processing space. This not only prevents the atmospheric gas from being entrained along with the conveyance of the object to be processed, but also prevents the atmospheric gas from being drawn into the processing space on the flow of the processing gas.

Here, the vicinity of the atmospheric pressure refers to a range of 1.013 × 10 ^{4 to} 50.663 × 10 ⁴ Pa, and considering the ease of pressure adjustment and the simplification of the apparatus configuration, 1.333 × 10 ⁴ to 10.664 × 10 ⁴ Pa is preferable, and 9.331 × 10 ^{4 to} 10.9797 × 10 ⁴ Pa is more preferable.

  According to the present invention, it is possible to suppress or prevent the atmospheric gas from flowing into the processing space, and to reduce the mixing of impurities into the processing gas. Therefore, a good surface treatment can be performed.

FIG. 1 is a side sectional view showing a plasma processing apparatus according to a first embodiment of the present invention. FIG. 2 is a perspective view of the plasma processing apparatus. FIG. 3 is an enlarged side sectional view showing a processing space of the plasma processing apparatus. FIG. 4 is a perspective view showing a plasma processing apparatus according to the second embodiment of the present invention. FIG. 5 is a side view showing a plasma processing apparatus according to the third embodiment of the present invention. FIG. 6 is a side cross-sectional view showing a modification of the tip structure of the processing gas blowing section and the curtain gas blowing section. FIG. 7 is a graph showing the results of Example 1. FIG. 8 is a graph showing the results of Example 2.

  1 to 3 show a first embodiment of the present invention. As shown in FIGS. 1 and 2, the plasma processing apparatus 1 includes a plasma head 10 and a second electrode 21. The second electrode 21 and the plasma head 10 face each other vertically (first direction), and a processing space 90 is formed between them. The workpiece 9 is passed through the processing space 90, and the plasma surface treatment of the workpiece 9 is performed. The surface treatment content in this embodiment is, for example, a surface wettability improvement (lyophilic) treatment of the workpiece 9. The workpiece 9 is a continuous sheet-like resin film, and is applied as, for example, an optical film for a polarizing plate or a flexible wiring of an electronic device. The width of the workpiece 9 (the dimension in the processing width direction orthogonal to the paper surface of FIG. 1) is, for example, several tens mm to several thousand mm. The thickness of the workpiece 9 is about several hundred μm. In FIG. 3, the thickness of the workpiece 9 is exaggerated.

  The plasma head 10 includes a first electrode 11, a holder 13, and a base 14. The first electrode 11 has a quadrangular cross-sectional shape and extends in the processing width direction (direction orthogonal to the first direction) orthogonal to the paper surface of FIG. The upper surface of the first electrode 11 constitutes the discharge surface 11a. The discharge surface 11a extends in the processing width direction while forming a plane orthogonal to the first direction. A temperature control path 11 c is formed inside the first electrode 11. The temperature of the electrode 11 can be controlled by circulating a temperature control medium such as cooling water through the temperature control path 11c.

  The length of the first electrode 11 in the processing width direction is set according to the width dimension of the workpiece 9 and is, for example, several tens mm to several thousand mm. The length of the first electrode 11 in the short direction (second direction orthogonal to both the first direction and the processing width direction, the left-right direction in FIG. 1) is, for example, several tens of millimeters to several tens of millimeters.

  A power source 2 is connected to the first electrode 11. Thus, the first electrode 11 is an electric field application electrode. The power supply 2 supplies, for example, pulsed (intermittent) high frequency power to the first electrode 11. The supplied power is not limited to the intermittent wave shape of the pulse wave, and may be a continuous wave shape such as a sine wave.

  A solid dielectric layer 12 is disposed on the first electrode 11. The solid dielectric layer 12 is in close contact with the discharge surface 11a and covers the entire discharge surface 11a. The solid dielectric layer 12 is composed of a flat plate made of a solid dielectric such as alumina. The thickness of the solid dielectric layer 12 is, for example, about 1 mm to several mm. The plate-like solid dielectric layer 12 has a larger area than the discharge surface 11a, and extends beyond the first electrode 11 on both sides in the processing width direction and both sides in the second direction. The length of the solid dielectric layer 12 in the processing width direction is, for example, several tens mm to several thousand mm. The length of the solid dielectric layer 12 in the second direction is, for example, several tens mm to several hundreds mm.

  The first electrode 11 is held by a holder 13. The holder 13 is made of an insulator such as resin or ceramics. The holder 13 has a recess 13a. The recess 13 a is open on the upper surface of the holder 13. The first electrode 11 is accommodated in the recess 13a. The upper surface of the holder 13 and the discharge surface 11a are flush with each other. The solid dielectric layer 12 also covers the upper surface of the holder 13.

  The second electrode 21 has a cylindrical shape whose axis is directed in the processing width direction. The length of the second electrode 21 in the processing width direction is set according to the width dimension of the workpiece 9 and is substantially the same as or longer than the length of the first electrode 11 in the processing width direction. Thousands of millimeters. The diameter of the second electrode 21 is sufficiently larger than the length of the first electrode 11 in the second direction (short direction), and further larger than the dimension of the plasma head 10 in the second direction, for example, several tens mm to several hundreds. mm.

  The second electrode 21 is electrically grounded via the ground line 2e. Thus, the second electrode 21 forms a ground electrode. By supplying a voltage from the power source 2, a plasma discharge 91 can be generated by forming a potential difference between the first electrode 11 and the second electrode 21.

  As shown in FIG. 3, the entire cylindrical outer peripheral surface of the second electrode 21 is covered with a solid dielectric layer 22 (not shown in FIG. 1). The solid dielectric layer 22 is composed of, for example, an alumina sprayed film. The thickness of the solid dielectric layer 22 is, for example, about 1 mm to several mm.

A processing space 90 near atmospheric pressure (including atmospheric pressure) is formed between the electrodes 11 and 21. Specifically, a processing space 90 is defined by the upper surface of the solid dielectric layer 12 of the first electrode 11 and the outer peripheral surface of the second electrode 21 on the lower side of the solid dielectric layer 22. The processing space 90 is the narrowest immediately below the axis of the second electrode 21. As the distance from the narrowest portion 90a in the second direction increases, the thickness of the processing space 90 gradually increases. The thickness _{g 0} of the narrowest portion 90a is, for example _{g 0} = is about 1mm~ number mm. Both ends of the processing space 90 in the second direction and both ends of the processing width direction communicate with the peripheral space of the plasma processing apparatus 1.

  The 2nd electrode 21 is connected with the rotation drive part which is not illustrated. The second electrode 21 is rotated around its axis by the rotation driving unit. A continuous sheet-shaped workpiece 9 is wound around the lower peripheral surface of the second electrode 21 and passed through the processing space 90. The workpiece 9 is transported by the rotation of the second electrode 21. Here, in FIG. 1, the 2nd electrode 21 is rotated counterclockwise, and the to-be-processed object 9 is conveyed in the substantially right direction. The conveyance speed of the workpiece 9 is relatively large, for example, about 20 m / min to 40 m / min. In addition, a general conveyance speed is about several m / min to tens of m / min.

A processing gas blowout unit 30 is disposed on a first side portion (one side portion, left side in FIG. 1) of the first electrode 11 in the plasma head 10 in the second direction. The blowing unit 30 is located upstream of the first electrode 11 in the transport direction of the workpiece 9. The blowing part 30 is configured by a vertical plate-like member. The end surface on the first side of the solid dielectric layer 12 and the side surface on the first side of the holder 13 are in contact with the side surface (the right side surface in FIG. 1) facing the first electrode 11 of the blowing unit 30. The upper end portion 31 of the blow-out portion 30 protrudes upward (in the first direction) toward the second electrode 21 from the upper surface of the solid dielectric layer 12 (the defining surface that defines the bottom of the processing space 90), and the second Close to the electrode 21. A vertical side surface of the protruding portion 31 facing the first electrode 11 defines an end portion (left end portion in FIG. 1) on the first side in the second direction of the processing space 90. Projecting amount from the solid dielectric layer 12 of the protrusion 31 is larger than the thickness g ₀ of the narrowest portion 90a. The upper end surface of the blowing part 30 is horizontal. A gap 93 is formed between the upper end surface of the blowing part 30 and the lower peripheral surface of the second electrode 21. The gap 93 is narrowest at the communication portion with the processing space 90. The upper and lower thickness of the narrowest part of the gap 93 is, for example, about several millimeters, and may be substantially the same as the thickness of the narrowest part 90a of the processing space 90, or may be smaller than the thickness of the narrowest part 90a. It may be larger than the thickness of the narrowest portion 90a.

  A processing gas introduction path 32 is formed inside the blowout portion 30. A processing gas source 3 is connected to a base end portion (lower end in FIG. 1) of the processing gas introduction path 32. Although not shown in detail, the processing gas introduction path 32 includes a dispersion path that disperses the processing gas from the processing gas source 3 in the processing width direction in the blowing unit 30. A processing gas outlet 33 is connected to the processing gas introduction path 32. The blow-out port 33 may be composed of a plurality of small holes arranged dispersed in the processing width direction, or may be composed of slots extending in the processing width direction. The blow-out port 33 extends from the process gas introduction path 32 toward the process space 90 inward in the second direction and slightly upward. The outlet 33 reaches a side surface of the protruding portion 31 facing the first electrode 11. Therefore, the outlet 33 opens toward one end portion (left in FIG. 1) of the processing space 90 in the second direction, and is directly connected to the processing space 90.

The composition of the processing gas is appropriately selected according to the surface treatment content of the workpiece 9. In the case of wettability improving treatment, the treatment gas preferably contains nitrogen (N ₂ ) as a main component. Here, the processing gas is composed of 100% nitrogen.

  A curtain gas blowing unit 40 is provided on the outer side of the blowing unit 30 in the second direction (the side opposite to the first electrode 11 side). The curtain gas blowing part 40 is configured by a vertical plate-like member and is exactly overlapped with the outer surface of the blowing part 30. The total thickness (dimension in the second direction) of the blowout portions 30 and 40 is about several tens mm to one hundred mm. The upper end surface of the curtain gas blowing unit 40 is flush with the upper end surface of the processing gas blowing unit 30. A gap 94 is formed between the upper end surface of the blowing part 40 and the lower peripheral surface of the second electrode 21. The processing space 90 is connected to the peripheral space on the first side (left in FIG. 1) in the second direction from the plasma processing apparatus 1 through the gaps 93 and 94.

  A curtain gas introduction path 42 is formed inside the blowout portion 40. The curtain gas source 4 is connected to the base end portion (lower end in FIG. 1) of the curtain gas introduction path 42. As the curtain gas, for example, an inert gas such as nitrogen is used. The processing gas source 3 and the curtain gas source 4 may be constituted by a common nitrogen gas source. Although detailed illustration is omitted, the introduction path 42 includes a dispersion path for dispersing the curtain gas from the curtain gas source 4 in the treatment width direction in the blowing unit 40. A curtain gas outlet 43 is connected to the introduction path 42. The curtain gas outlet 43 may be configured by a plurality of small holes arranged in a dispersed manner in the processing width direction, or may be configured by slots extending in the processing width direction. The outlet 43 extends upward from the introduction path 42, reaches the upper end surface of the outlet 40, and opens toward the gap 94.

A shielding member 50 is disposed on the second side portion (the other side portion, right side in FIG. 1) opposite to the blowing portion 30 in the plasma head 10 in the second direction. The shielding member 50 is located downstream of the first electrode 11 in the conveyance direction of the workpiece 9. The shielding member 50 has a vertical plate shape. The thickness of the shielding member 50 in the second direction is not particularly limited, but is preferably sufficiently smaller than the thickness of the blowing portions 30 and 40, for example, about several mm to several tens of mm. The side surface (the left side surface in FIG. 1) of the shielding member 50 facing the first electrode 11 is in contact with the second side end surface of the solid dielectric layer 12 and the second side surface of the holder 13. The upper end portion 51 of the shielding member 50 protrudes above (the first direction toward the second electrode 21) above the upper surface of the solid dielectric layer 12 (the surface defining the bottom of the processing space 90), and the second electrode 21. Is close to. A vertical side surface of the protruding portion 51 facing the first electrode 11 defines an end portion (right end portion in FIG. 1) on the second side in the second direction of the processing space 90. Projecting amount h from the solid dielectric layer 12 of the shielding member 50, the thickness _{g 0} greater than _{(h> g} 0) of the narrowest portion 90a (height of the protrusion 51). Preferably, the protruding amount h of the shielding member 50 is 2 mm or more (h ≧ 2 mm), preferably 3 mm or more (h ≧ 3 mm). Further, the protruding amount h is equal to or more than the protruding amount of the protruding portion 31 of the blowing portion 30 from the solid dielectric layer 12.

A gap 95 is formed between the upper end surface of the shielding member 50 and the lower peripheral surface of the second electrode 21. The thickness above and below the gap 95 is not particularly limited as long as it can pass the workpiece 9 and may be substantially the same as the thickness of the narrowest portion 90a of the processing space 90. It may be smaller than the thickness or larger than the thickness of the narrowest portion 90a. Here, the thickness above and below the gap 95 is about 1 mm to about several tens of mm. The processing space 90 is connected to the peripheral space on the second side (right in FIG. 1) in the second direction from the plasma processing apparatus 1 through the gap 95.
The plasma head 10 is not provided with a suction / exhaust mechanism for sucking used processing gas or the like.

A method for surface-treating the workpiece 9 using the plasma processing apparatus 1 configured as described above will be described.
The workpiece 9 is held on the lower peripheral surface of the second electrode 21, and the second electrode 21 is rotated counterclockwise in FIG. 1, for example, so that the workpiece 9 is moved in the right direction by, for example, 20 m / min. Transports at a high speed of about 40 m / min. High frequency power is supplied from the power source 2 to the first electrode 11, and an electric field is applied between the first electrode 11 and the second electrode 21. As a result, a plasma discharge 91 near the atmospheric pressure is generated at the central portion in the second direction in the processing space 90 (the portion 91 corresponding to the first electrode 11).

In parallel with the above voltage supply, the processing gas (N ₂ ) is sent from the processing gas source 3 to the processing gas introduction path 32 and dispersed in the processing width direction in the processing gas introduction path 32. This processing gas is blown out from the blowout port 33. Since the blow-out port 33 opens at the first side end portion (left end in FIG. 1) of the processing space 90, the processing gas can be directly introduced into the processing space 90, and further, the processing gas can be introduced into the plasma discharge portion 91. It can be flowed reliably. In addition, the flow of the processing gas is uniform in the processing width direction. This processing gas is turned into plasma (including excitation, decomposition, activation, radicalization, ionization, etc.) in the plasma discharge section 91. This plasma-ized processing gas (nitrogen plasma) contacts the workpiece 9 on the lower peripheral surface of the second electrode 21. As a result, the surface of the workpiece 9 can be subjected to plasma treatment (wetting improvement treatment). By continuously passing the workpiece 9 through the treatment space 90 by the rotation of the second electrode 21, the workpiece 9 can be plasma-treated in its extending direction. In addition, the flow from the outlet 33 can be made uniform in the processing width direction, and the upper and lower thicknesses of the processing space 90 and the gaps 93, 94, 95 are set to be uniform in the processing width direction. Thus, the processing degree of the workpiece 9 can be made uniform in the processing width direction.

The air (atmosphere gas) on the first side from the plasma head 10, that is, the upstream side in the transport direction, tends to be caught in the processing space 90 together with the object 9 due to the viscosity of the object 9. In particular, since the conveyance speed is high (for example, about 20 m / min to 40 m / min), the entrainment effect is also large. On the other hand, the processing space 90 is a substantially closed space by the second electrode 21, the solid dielectric layer 12, and the projecting portions 31 and 51. I can press. Thereby, the internal pressure of the processing space 90 can be made higher than the pressure (environmental pressure) in the peripheral space of the plasma processing apparatus 1 within a range near atmospheric pressure. In particular, by blocking the flow of the processing gas at the downstream end of the processing space 90 by the protruding portion 51 of the shielding member 50 and substantially damming it, the internal pressure of the processing space 90 can be reliably increased from the environmental pressure. Thereby, even if the conveyance speed is high, the air can be sufficiently suppressed from flowing into the processing space 90, and the amount of air mixed into the processing gas can be made minute. The protrusion height h of the protrusions 51 and greater than the discharge gap g _0, preferably h ≧ 2 mm, more preferably by a h ≧ 3 mm, can be reliably suppressed air flowing into the processing space 90, to the process gas The amount of air mixed in can be made very small.

On the upstream side (first side) of the processing space 90, the protrusion 31 of the blow-out unit 30 can directly prevent air entrainment accompanying the carry-in of the workpiece 9. Further, the upstream air can be prevented from being drawn into the processing space 90 due to the blowing of the processing gas. Further, curtain gas (N ₂ ) from the curtain gas source 4 is blown out from the blow-out port 43. Thereby, a gas curtain can be formed on the upstream side of the processing space 90, and the entrainment of the air can be reliably prevented. Therefore, the amount of air mixed into the processing gas can be made even smaller.

  The processing gas filled in the processing space 90 is discharged to the outside through the gaps 93, 94, 95, and further discharged to the outside from both ends of the processing space 90 in the processing width direction. By this discharge flow, the air toward the processing space 90 can be pushed back, and the inflow of air into the processing space 90 can be more reliably suppressed.

As a result, the oxygen concentration in the processing space 90 can be made as small as about 100 ppm to 1000 ppm, for example. By suppressing the oxygen concentration to 1000 ppm or less, it is possible to reliably prevent the processing performance from being impaired. Moreover, the wettability of the workpiece 9 can be remarkably improved by adding a small amount of oxygen from the atmosphere to the processing gas composed of 100% nitrogen.
According to the plasma processing apparatus 1, it is not necessary to provide a suction / exhaust mechanism in the plasma head 10 to prevent the inflow of air, and the apparatus configuration can be simplified. Furthermore, the structure of the first electrode 11 can be simplified by making the discharge surface 11a flat.

Next, another embodiment of the present invention will be described. In the following embodiments, the same reference numerals are given to the drawings for the same configurations as those already described, and the description thereof is omitted.
The location of the plasma head 10 with respect to the second electrode 21 is not limited to the lower side of the second electrode 21. In the second embodiment shown in FIG. 4, the plasma head 10 is rotated 90 degrees to the right with respect to that of the first embodiment and disposed on the right side of the second electrode 21. The first electrode 11 and the second electrode 21 in the plasma head 10 are opposed to the left and right. Therefore, the first direction in the second embodiment is horizontally oriented. The second direction (the direction perpendicular to both the first direction and the processing width direction) is vertically oriented.

The plasma head 10 is not limited to one, and may be plural (two or more). In the third embodiment shown in FIG. 5, the plasma processing apparatus 1 includes two plasma heads 10. These plasma heads 10 are arranged at intervals in the circumferential direction of the second electrode 21. A first direction (a facing direction between the electrodes 11 and 21) and a second direction (a direction orthogonal to both the facing direction and the processing width direction) are determined for each plasma head 10. A processing space 90 is formed between each plasma head 10 and the second electrode 21. In the entire plasma processing apparatus 1, two processing spaces 90 are formed at intervals in the circumferential direction of the second electrode 21. Accordingly, the surface treatment can be performed twice in the two treatment spaces 90 while the workpiece 9 is conveyed in the circumferential direction of the second electrode 21. Thereby, the surface treatment degree with respect to the to-be-processed object 9 can be raised further. The surface treatment content in the first-stage (upstream side in the transport direction) plasma treatment 10 and the surface treatment content in the second-stage (downstream side in the transport direction) plasma head 10 may be different from each other.
The number of plasma heads 10 and thus the number of processing spaces 90 may be three or more.

  FIG. 6 shows a modified example of the blowing parts 30 and 40. In this modification, the upper end surface of the blowing part 30 is inclined so as to be along the peripheral surface of the second electrode 21. For this reason, the gap 93 between the second electrode 21 and the blowing portion 30 is generally the same thickness. Similarly, the upper end surface of the blowing part 40 is slanted along the peripheral surface of the second electrode 21, and the gap 94 between the second electrode 21 and the blowing part 40 has substantially the same thickness as a whole. It has become. The inclination angle of the upper end surface of the blowing unit 40 is larger than the inclination angle of the upper end surface of the blowing unit 30. According to this modification, the flow resistance of the gaps 94 and 93 can be increased, and the atmospheric gas such as external air can be more reliably suppressed or prevented from flowing into the processing space 90 through the gaps 94 and 93.

The present invention is not limited to the above-described embodiment, and various aspects can be employed without departing from the spirit of the present invention.
For example, the solid dielectric layer may be provided on at least one of the electrodes 11 and 21. Either one of the solid dielectric layers 12 or 22 may be omitted. When the solid dielectric layer 12 is omitted, the shielding member 50 only needs to protrude in the first direction toward the second electrode 21 from the discharge surface 11a.
The shielding member 50 may be disposed on the upstream side in the transport direction of the workpiece 9 with respect to the first electrode 11. The blowing unit 30 may be disposed on the downstream side in the transport direction of the workpiece 9 with respect to the first electrode 11.
The conveyance speed of the workpiece 9 is not limited to 20 m / min to 40 m / min, and may be less than 20 m / min or greater than 40 m / min.
The present invention is not limited to wettability improving treatment, and can be applied to various surface treatments such as other surface modification treatment such as water repellency, cleaning, and film formation.

Examples will be described. Needless to say, the present invention is not limited to the following examples.
In Example 1, the amount of mixed oxygen into the processing space 90 with respect to the protrusion amount h of the shielding member 50 was examined using an apparatus having substantially the same structure as that of the first embodiment (FIGS. 1 to 3).
The thickness of the narrowest portion 90a of the processing space 90 at the lower end of the second electrode 21 was about 1 mm.
The protrusion amount h of the shielding member 50 was adjusted in the range of h = 0 to 6 mm.
The conveyance speed of the to-be-processed object 9 was made into 2 types, 20 m / min and 40 m / min.
Nitrogen (N ₂ ) 100% was used as a processing gas.
The supply flow rate of the processing gas per unit length (1 m) in the processing width direction was 7 slm.

The results are shown in FIG. It has been confirmed that by making the protruding amount h of the protruding portion 51 larger than the discharge gap g ₀ (h> g ₀ ), the inflow of air into the processing space 90 can be suppressed and the oxygen concentration in the processing space 90 can be greatly reduced. It was. With the protrusion amount h = 2 mm, the effect of reducing the oxygen concentration could be expressed. It was confirmed that when the protrusion amount h is 3 mm or more (h ≧ 3 mm), the oxygen concentration can be reliably reduced. Moreover, the higher the conveyance speed, the greater the effect of reducing the oxygen concentration.

In Example 2, the effect of curtain gas was investigated using an apparatus having substantially the same structure as that of the first embodiment (FIGS. 1 to 3).
The blowing flow rate of curtain gas from the blowing unit 40 was adjusted in the range of 0 to 80 L / min.
The length of the plasma head 10 and the second electrode 21 in the processing width direction was about 2 m.
The conveyance speed of the workpiece 9 was set to three types of 20 m / min, 30 m / min, and 40 m / min.
The protrusion amount h of the shielding member 50 was h = 6 mm.
Other apparatus configurations and processing conditions were the same as those in Example 1.

  The results are shown in FIG. It has been confirmed that when the conveyance speed is 30 m / min or higher, the inflow of air into the processing space 90 can be further suppressed and the oxygen concentration in the processing space 90 can be further reduced as the curtain gas flow rate is increased. .

  The present invention is applicable to, for example, an optical film adhesion improving process and a flexible wiring material surface process.

DESCRIPTION OF SYMBOLS 1 Plasma processing apparatus 2 Power supply 2e Ground line 3 Processing gas source 4 Curtain gas source 9 To-be-processed object 10 Plasma head 11 1st electrode 11a Discharge surface 11c Temperature control path 12 Solid dielectric layer 13 Holder 13a Recessed part 14 Base 21 2nd electrode 22 Solid Dielectric Layer 30 Process Gas Blowout Unit (Blowout Member)
31 Protruding portion 32 Processing gas introduction path 33 Processing gas outlet 40 Curtain gas outlet 42 Curtain gas inlet 43 Curtain gas outlet 50 Shielding member 51 Protruding portion 90 Processing space 90a Narrowest portion 91 Plasma discharge portion 93 21)
94 Clearance (between 40 and 21)
95 Clearance (between 50 and 21)
g ₀ Narrowest gap in processing space h

Claims (5)

Plasma processing that converts the processing gas into plasma by applying an electric field in a processing space near atmospheric pressure, and plasma-treats the surface of the processing object by bringing the processing gas into contact with the processing object that passes through the processing space In the device
A first electrode for applying the electric field having a planar discharge surface perpendicular to the first direction;
The processing space is formed between the first electrode and a cylindrical shape with an axis lined in a processing width direction orthogonal to the first direction, and the workpiece is rotated by rotating around the axis line. A second electrode to be conveyed;
A blow-out portion that is disposed on one side of a second direction perpendicular to both the first direction and the processing width direction of the first electrode, and introduces the processing gas into the processing space;
The first electrode is disposed on the other side portion in the second direction, and the discharge surface or the surface of the solid dielectric layer that covers the discharge surface defines the processing space toward the second electrode. A shielding member protruding in one direction;
The plasma processing apparatus is characterized in that the protruding amount of the shielding member is larger than the thickness of the narrowest portion of the processing space.   The plasma processing apparatus according to claim 1, wherein a protruding amount of the shielding member is 3 mm or more.   The plasma processing apparatus according to claim 1, wherein a conveyance speed of the object to be processed is about 20 m / min to 40 m / min.   The plasma processing apparatus according to claim 1, wherein the shielding member is disposed downstream of the first electrode in the conveyance direction of the object to be processed.   The blowing portion has a protruding portion that protrudes in the first direction toward the second electrode from a surface that defines the processing space of the discharge surface or the solid dielectric layer, and the protrusion of the protruding portion The plasma processing apparatus according to any one of claims 1 to 4, wherein a blow-out port for blowing out the processing gas is opened on a side surface facing the processing space.

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