JP2004363539A - Plasma-aided surface treatment method and treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma-aided surface treatment method and treatment apparatus whereby a treatment area is enlarged and gas utilization efficiency is improved. <P>SOLUTION: A gas is forced to flow through a flow path 24 provided in between electrodes 20, 22 facing each other, and discharge is started in between the electrodes 20, 22 for the activation of the gas in the flow path 24. The flow of the activated gas is split or enlarged for deceleration for the acceleration of the diffusion of the gas, and the gas with its diffusion accelerated is blown onto a workpiece 70. In the plasma-aided surface treatment apparatus 10, the flow path 24 and an opening 36 are connected, the flow of gas out of the flow path 24 is split or enlarged for deceleration, and a diffusion section 32 is provided for accelerating the diffusion of the gas. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a plasma surface treatment method and a treatment apparatus, and more particularly, to a plasma surface treatment method and a treatment apparatus for treating a surface of an object to be treated with a gas activated by discharge.

Various treatments (etching, ashing, modification, thin film formation, etc.) are performed on the surface of the object by spraying a gas containing a chemically active excited species generated by the plasma discharge onto the object. It has been proposed to perform the plasma surface treatment without using a vacuum. Generally, excited active species generated by plasma discharge have a short life under atmospheric pressure, so that the gas flow path from the plasma generator to the workpiece is straight so that it can reach the workpiece surface in a short time. (For example, see Patent Documents 1 and 2).
Japanese Patent No. 3207469 JP-A-11-335868

  However, when the flow path is formed in a straight line as described above, the area in which the object can be processed is limited. Therefore, in order to process a large area at the same time, it is necessary to provide a large number of combinations of the plasma generation unit and the flow path, but the configuration is not easy, for example, it is difficult to arrange them close to each other. Further, in the case of processing in a large amount, it is required to increase the gas use efficiency as much as possible.

  In view of the above, an object of the present invention is to provide a plasma surface treatment method and a treatment apparatus capable of increasing a treatment area and improving gas use efficiency.

  The present invention provides the following plasma surface treatment method and treatment apparatus to achieve the above object.

  The plasma surface treatment method of the present invention is a first step of flowing a gas through a flow path provided between opposed electrodes, and a second step of discharging between the electrodes and activating the gas flowing through the flow path, The method includes a third step of dividing or expanding the flow of the activated gas to decelerate the flow, thereby promoting the diffusion of the gas, and a fourth step of spraying the gas, which has promoted the diffusion, onto the object.

  In the above method, the excited activating species is generated in the gas flowing through the flow channel by the discharge between the electrodes. Since the diffusion of the excited activated species is promoted by the deceleration of the flow, a gas having a uniform concentration distribution of the excited activated species is blown onto the object.

  According to the above method, it is possible to uniformly and efficiently process a wider range by making the concentration distribution of the excitation activated species uniform. Therefore, the processing area can be enlarged and the gas use efficiency can be increased.

  Preferably, in the fourth step, the gas, which has promoted diffusion, is blown only to the workpiece. Since all of the gas that promoted diffusion is blown onto the object, the gas can be used effectively.

  Preferably, in the fourth step, the gas, which has promoted diffusion, is sprayed onto the object from a plurality of locations. Gas can be blown onto the object from a plurality of locations to increase the processing area.

  Preferably, in the fourth step, the gas decelerated in the third step is blown onto the object at the same speed. Since the gas flow rate may be the same in the portion where the gas is decelerated in the third step and in the portion where the gas is blown to the object in the fourth step, it is not necessary to change the shape of the cross section of the flow path. Therefore, plasma surface treatment can be performed with a simple configuration.

  Preferably, in the fourth step, the flow of the gas decelerated in the third step is restricted, and the velocity of the gas is increased and the gas is blown onto the workpiece. By increasing the speed of the gas blown to the processing object, the processing of the processing object can be promoted and stabilized, and the processing efficiency can be increased. In addition, since the distance from the object to be processed can be increased, workability can be improved.

  Preferably, in the third step, the speed of the decelerated gas is increased, and then the speed is reduced again to further promote the diffusion of the gas. Thereby, the concentration distribution of the gas can be made more uniform. Further, the number of branches of the gas is increased, and the gas is blown to the object to be processed in a wider range, so that the processing area can be further increased.

  Preferably, the method further includes a fifth step of collecting the gas sprayed on the object by suctioning the gas from around the sprayed position. Since the flow of gas is stable with respect to the object to be processed, processing unevenness can be eliminated.

  More preferably, in the fourth step, the gas is blown onto the workpiece from a plurality of openings extending in parallel, and in the fifth step, a plurality of gas extending alternately in parallel with the openings are provided. The gas blown to the object to be processed is sucked and collected from the suction part of the above. By providing the openings and the suction units alternately in parallel with each other, it is possible to uniformly process a large area.

  Preferably, the gas activated by the discharge between the electrodes contains 90% by volume or more of nitrogen gas. Gas containing 90% by volume or more of nitrogen gas has a longer lifetime of the excited activated species generated by the discharge between the electrodes than in the case of using other gases, so that even if the distance from the electrodes is increased, The gas containing the excitation activated species reaches the object to be processed. Therefore, the configuration is easy. In addition, a gas containing 90% by volume or more of a nitrogen gas is relatively inexpensive and easily available, so that it is suitable particularly when a large amount is processed.

  Preferably, each step of the plasma surface treatment method described above is performed in an environment at or near atmospheric pressure. Since no vacuum equipment is required, processing can be performed at low cost.

  Further, in the plasma surface treatment apparatus of the present invention, a gas is supplied to a flow path provided between opposed electrodes, and the gas passing through the flow path is activated by discharge between the electrodes. It is of a type that is sprayed from the section onto the object to be processed. The plasma surface treatment apparatus includes a diffusion unit that communicates the flow path with the opening, divides or expands the flow of the gas from the flow path, reduces the flow rate, and promotes the diffusion of the gas.

  In the above configuration, the excitation activated species is generated in the gas flowing through the flow path by the discharge between the electrodes. Since the diffusion of the excited activated species is promoted in the diffusion section, a gas having a uniform concentration of the excited activated species is blown from the opening onto the object. By making the concentration distribution of the excitation activated species uniform, it is possible to treat a wider range uniformly and efficiently. Therefore, the processing area can be enlarged and the gas use efficiency can be increased.

  Preferably, the opening faces only the object to be processed. Since all of the gas that has promoted diffusion can be sprayed from the opening to the object to be processed, the gas can be used effectively.

  Preferably, one flow path communicates with the plurality of openings through the diffusion unit. By providing a plurality of openings, the processing area can be increased.

  Preferably, the diffusion portion is formed continuously with the opening. Since it is not necessary to make the opening larger or smaller than the diffusion part, the configuration can be simplified.

  Preferably, a restrictor having a reduced cross section is provided between the diffusion section and the opening, and the gas from the diffusion section is accelerated and blown from the opening to the workpiece. By increasing the speed of the gas blown to the processing object, the processing of the processing object can be promoted and stabilized, and the processing efficiency can be increased. In addition, since the distance from the object to be processed can be increased, workability can be improved.

  Preferably, a throttle unit communicating with the diffusion unit to reduce the flow of the gas from the diffusion unit, and a communication between the throttle unit and the opening to enlarge the flow of the gas from the throttle unit. A second diffusion unit. By the diffusion unit and the second diffusion unit, the gas concentration distribution can be made more uniform. Further, the number of branches can be increased, and an opening can be provided in a wider range, so that the processing area can be further increased.

  Preferably, a suction unit is provided around the opening to suck and collect the gas ejected from the opening. Since the flow of gas is stable with respect to the object to be processed, processing unevenness can be eliminated.

  More preferably, the apparatus includes a plurality of openings that extend in parallel and linearly, and a plurality of suction units that extend in parallel and linearly alternately with the openings. By providing the openings and the suction units alternately in parallel with each other, it is possible to uniformly process a large area.

  Preferably, the gas activated by the discharge between the electrodes contains 90% by volume or more of nitrogen gas. Gas containing 90% by volume or more of nitrogen gas has a longer lifetime of the excited activated species generated by the discharge between the electrodes than in the case of using other gases, so that even if the distance from the electrodes is increased, The gas containing the excitation activated species reaches the object to be processed. Therefore, the configuration is easy. In addition, a gas containing 90% by volume or more of a nitrogen gas is relatively inexpensive and easily available, so that it is suitable particularly when a large amount is processed.

  Preferably, the object is disposed under an environment of atmospheric pressure or a pressure close to atmospheric pressure. Eliminating the need for vacuum equipment and the like allows processing at low cost.

  By providing a structure that divides or diffuses a gas activated by a discharge between opposing electrodes, a range in which objects to be processed can be simultaneously processed can be expanded. Further, the same amount of gas can be used more efficiently. That is, the processing area can be increased, and the gas use efficiency can be increased.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic diagram showing an example of the basic configuration of the plasma surface treatment apparatus of the present invention. The plasma surface treatment apparatus 2 generally includes a pair of electrodes 20 and 22 facing each other, a processing unit 6 provided adjacent to the electrodes 20 and 22 in a space 13 formed by the housing 12, and a processing unit 6. And a moving stage 80 on which the object 70 is placed facing.

  The atmosphere gas supply unit 14 supplies the atmosphere gas into the space 13 from the atmosphere gas inlet 12 a of the housing 12 as indicated by an arrow 15. The gas supply unit 16 supplies gas from the gas supply line 17 to one end 4 side of the flow path 24 formed between the pair of electrodes 20 and 22, and supplies the gas to the processing unit 6 provided on the other end side of the flow path 24. A gas is blown from the opening 8 toward the processing object 70. The gas in the space 13 is exhausted from a gas exhaust port 12b of the housing 12, as indicated by an arrow 18.

  Note that there is no particular need to perform processing in a closed system in the housing 12 or to supply atmospheric gas from the atmospheric gas supply unit 14. The processing may be performed in an open system without the housing 12 or the atmospheric gas supply unit 14. For example, an active gas may be blown in a state where the object to be processed 70 is covered with a lid-like member to absorb the exhaust gas.

  A voltage is applied to the electrodes 20 and 22 by the power supply 26, and plasma discharge occurs in the flow path 24. Thereby, the gas passing through the flow path 24 is activated. The activated gas is blown from the opening 8 toward the object 70 to perform plasma processing on the object 70. Since the portion of the workpiece 70 facing the opening 8 and the area in the vicinity thereof are processed, the entire workpiece 70 is processed by moving the moving stage 80 as indicated by an arrow 82, for example.

  Instead of moving the object 70, the electrodes 20 and 22 (the processing section 6) may be moved, or both may be moved.

  Next, each embodiment of the present invention will be described with reference to FIGS. Each embodiment of the present invention is obtained by improving the configuration of the processing unit 6 in FIG. Hereinafter, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description will be focused on the differences.

  FIG. 2 is a schematic diagram illustrating a configuration of the plasma surface treatment apparatus 10 according to the first embodiment of the present invention. The processing unit 30 provided adjacent to the electrodes 20 and 22 has a plurality of openings 36. The flow path 24 and the opening 36 communicate with each other through a space 32 that enlarges the flow and a throttle 34 that narrows the flow. The space 32 is a diffusion unit that promotes diffusion of a gas activated by a discharge between the electrodes 20 and 22, and a more uniform gas can be blown from the opening 36 onto the object 70. . By injecting the gas whose speed has been increased by the restrictor 34 onto the processing target 70, the processing of the processing target 70 is promoted and stabilized, and the processing efficiency can be increased. In addition, the distance between the opening 36 and the workpiece 70 can be increased, so that workability can be improved. By providing a plurality of openings 36, a large area can be processed.

  Although the object 70 is not particularly limited, for example, a silicon substrate, a glass plate, a resin film, or the like can be processed. The workpiece 70 may be transported using a mechanism different from the moving stage 80.

The atmosphere gas is not particularly limited, but for example, air can be used. The gas supplied from the gas supply unit 16 to the flow path 24 via the gas supply line 17 may be any gas that is activated by the discharge between the electrodes 20 and 22. For example, a gas mixture of O ₂ and CF ₄ or N 2 Gas containing ₂ is used. Since the activation time varies depending on the type of gas, the diffusion path length is not uniform. Examples of the gas having a long activation time include N ₂ , O ₂ , CF ₄ , and a rare gas, and the diffusion path length extends to several tens of cm. It is preferred that these gases have a long activation time of 90% by volume or more. In particular, those containing 90% by volume or more of N ₂ are preferable because they have a long activation time, are inexpensive and are easily available. In the flow path 24, there is only required a differential pressure necessary for the gas supplied from the gas supply unit 16 to flow toward the opening 36, and the setting of the pressure is not particularly limited. The length of the stop 34 is about several mm to several tens mm.

  The shape of the pair of electrodes 20 and 22 is a parallel plate, a parallel roll, or the like, and the height is about several mm to several cm. Appropriate waveform voltage at which plasma discharge occurs may be applied to the electrodes 20 and 22.

  The processing time and the state after the processing are not particularly limited. Further, a combination with a pre-treatment, a post-treatment, a heat treatment, or the like is also free.

  FIG. 5 is an example of a profile of an object to be processed when processing is performed using the first embodiment and the basic configuration. Dotted line 50 indicates the case where the configuration (basic configuration) of FIG. 1 is used, and solid line 52 indicates the case of using the configuration (first embodiment) of FIG. Using the same amount of gas, the silicon wafer coated with the resist as the object to be processed 70 faces the openings 8, 36 of the object to be processed 70 when the ashing process is performed without moving relative to the openings 8, 36. 3 shows the shape of the region to be processed.

  In the basic configuration of FIG. 1, only the portion immediately below the flow path 24 (the opening 8) is removed. In the first embodiment of FIG. 2, not only the portion immediately below the two openings 36 but also the vicinity thereof. Diagonally removed. That is, it can be seen that the first embodiment has a larger removal amount of the resist than the basic configuration and can perform the processing more efficiently.

  FIG. 3 is a schematic diagram illustrating a configuration of a plasma surface treatment apparatus 10s according to the second embodiment of the present invention. The second and subsequent embodiments will be described focusing on the differences from the first embodiment. The resin processing section 31 provided adjacent to the electrodes 20 and 22 has one opening 37, and has a space 33 between the flow path 24 and the opening 37 for expanding the flow. The space 33 is a diffusion portion for promoting the diffusion of the gas activated by the discharge between the electrodes 20 and 22. In the space 33, the activated gas is diffused and is made more uniform, so that the opening is formed. From 37, it is sprayed onto the object 70. Since the opening 37 can be enlarged, a large area can be processed. Although FIG. 3 shows a special case where the opening 37 and the space 33 are continuous and have the same cross-sectional area, the cross-sectional areas may be different.

  FIG. 6 is an example of a profile of the workpiece 70 when processing is performed using the second embodiment and the basic configuration. A dotted line 50 shows a case where the configuration (basic configuration) of FIG. 1 is used, and a solid line 54 shows a case of using the configuration (second embodiment) of FIG. Similarly to FIG. 5, using the same amount of the activation gas, the object 70 (the silicon wafer coated with the resist) is subjected to the ashing process without being moved with respect to the openings 8 and 37. 3 shows a profile of a region to be processed.

  In the basic configuration of FIG. 1, only the portion directly below the flow path 24 (the opening 8) is removed, whereas in the second embodiment of FIG. ing. In other words, it can be seen that the second embodiment has a larger removal amount of the resist than the basic configuration and can perform the processing more efficiently.

  FIG. 4 is a schematic diagram illustrating a configuration of a plasma surface treatment apparatus 10t according to a third embodiment of the present invention. The third embodiment is a combination of the first embodiment of FIG. 2 and the second embodiment of FIG. The processing section 40 provided adjacent to the electrodes 20 and 22 includes a first resin plate 40a disposed on the electrodes 20 and 22 side and a second metal plate 40b disposed on the workpiece 70 side. Have been. A first space 42 as a first diffusion portion is formed between the first plate 40a and the second plate 40b. The first plate 40 has a shallow concave portion formed in the lower portion, and a first space 42 is formed by the concave portion and the upper surface of the second plate 40b. A second space 44 as a second diffusion portion is formed on the side of the moving stage 80 of the second plate 40b, and a communication hole 43 as a throttle portion is formed on the side of the second plate 40b on the first plate 40a side. Is formed.

The gas supplied from the gas supply unit 16 to the flow path 24 is supplied to the first space 42 wider than the flow path 24 and decelerated, and the diffusion in the first space 42 is promoted to make the flow velocity distribution uniform. Is performed. Then, the gas supplied to the first space 42 is supplied to the plurality of second spaces 44 via the communication holes 43. Here, the gas passing through the communication hole 43 is once accelerated when passing through the communication hole 43 and is supplied to the second space 44. The gas supplied to the second space 44 is decelerated again, and its diffusion is promoted in the second space 44 so that the flow velocity distribution is made uniform. .
By repeating the diffusion of the gas in the first and second spaces 42 and 44 in this manner, the uniformity of the gas is further promoted, and more openings 46 are arranged in a wider range, so that the object 70 Can be simultaneously processed.

  Further, the second plate 40b is grounded via the ground wire 27, thereby preventing occurrence of abnormal discharge between the second plate 40b and the object 70.

  Next, a fourth embodiment of the present invention will be described with reference to FIGS.

FIG. 7 is a sectional view of a main part of a plasma surface treatment apparatus according to a fourth embodiment of the present invention. The processing unit 50 has a first plate 52 made of resin and a second plate 56 made of metal. The first plate 52 is overlaid on the second plate 56 and is in close contact with each other, and is fixed to the electrodes 20 and 22 via the holder 28 made of an insulating material.
Further, the second plate 56 is grounded via a ground wire (not shown) to prevent occurrence of abnormal discharge between the second plate 56 and the object 70.

  As shown in FIGS. 7 and 8, a relatively narrow bottomed groove 53 is formed on the upper surface 52 a of the first plate 52, and the bottom surface 53 a of the bottomed groove 53 and the lower surface 52 b of the first plate 52 are formed. And a relatively small number (two in FIG. 8) of slits 54 are formed in parallel with each other.

  As shown in FIGS. 7 and 9, a relatively wide bottomed groove 57 is formed on the upper surface 56 a of the second plate 56, and the bottom surface 57 a of the bottomed groove 57 and the lower surface 56 b of the second plate 56 are formed. And a relatively large number (six in FIG. 9) of slits 58 are formed in parallel with each other. Further, through holes 59 are formed at positions away from both ends of the slit 58 as suction portions. The through hole 59 extends in a direction perpendicular to the slit 58.

The bottom surface 53 a of the bottomed groove 53 is located below the flow path 24 formed between the electrodes 20 and 22, and the lower surface of the holder 28 is located above the slit 54. Therefore, the flow path 24 and the slit 54 are not formed on the same straight line.
The bottom surface 57 a of the bottomed groove 57 is located below the slit 54, and the lower surface of the first plate is located above the slit 58. Therefore, the slit 54 and the slit 58 are not formed on the same straight line.

  As shown in FIG. 7, the gas activated in the flow path 24 formed between the pair of electrodes 20 and 22 is sprayed on the bottom surface 53 a of the bottomed groove 53, and then the gas is activated on the first plate 52. The flow velocity distribution is made uniform by diffusion in the space (first diffusion section) formed by the bottom groove 53. Then, after being sprayed into the bottomed groove 57 of the second plate 56 through the slit 54 which is a narrowed portion, the space is further formed in the space (the second diffusion portion) formed by the bottomed groove 57 of the second plate 56. The flow velocity distribution is made uniform by the diffusion, and the flow is sprayed onto the object 70 from a large number of slits 58 which are apertures. By branching the flow of the activated gas and spraying it from a large number of slits 58 onto the processing object 70, the processing area can be enlarged and the processing can be performed more efficiently.

  The gas blown to the workpiece 70 is collected by suction from the through holes 59 of the second plate 56 as a suction unit. Thereby, the flow of gas to the processing object 70 can be stabilized, and processing unevenness can be eliminated.

FIG. 10 is a cross-sectional view of a main part showing a first modification of the fourth embodiment. In the slit 58s of the second plate 56s of the processing unit 50s, an enlarged portion 58x is provided at an end facing the workpiece 70. The flow of the activated gas spreads at the expanding portion 58x when it is blown onto the processing object 70, so that the processing area can be expanded.
Further, the second plate 56s is grounded via a ground wire (not shown), thereby preventing occurrence of abnormal discharge between the second plate 56s and the workpiece 70.

  FIG. 11 is a cross-sectional view of a main part showing a second modification of the fourth embodiment. The processing unit 50r provided adjacent to the electrodes 20 and 22 includes a first plate 52r made of resin and a second plate 56r made of metal.

On the side of the second plate 56r on the periphery of the first plate 52r, a concave groove 72r which is depressed toward the inside of the first plate 52r is formed. On the first plate 52r side of the periphery of the second plate 56r, a protruding ridge 71r protruding toward the first plate 52r is formed. The convex portion 71r of the second plate 56r is inserted and fitted into the concave groove 72r of the first plate 52r, and is fixed in a state where the second plate 56r is positioned on the first plate 52r.
Further, the second plate 56r is grounded via a ground wire (not shown), thereby preventing occurrence of abnormal discharge between the second plate 56r and the object 70.

Here, the bottomed groove is not formed in the first plate 52r, and the first plate 52r can be manufactured at low cost.
The activated gas is made uniform by diffusion in a space (second diffusion portion) formed by the bottomed groove 57 on the upper surface of the second plate 56r, and then is processed through a large number of slits 58 serving as a stop. Sprayed at 70. By branching the flow of the activated gas and blowing it to the processing object 70 from the many slits 58, the processing area can be enlarged and the processing can be performed more efficiently.

  FIG. 12 is an enlarged sectional view of a main part showing a third modification of the fourth embodiment. Suction units 60 are provided alternately with the slits 58 of the second plate 56. Each suction unit 60 is disposed on the lower surface 56b of the second plate 56 and has a suction port 62 and a flow path 64 communicating with the suction port 62. The gas blown from each slit 58 to the processing object 70 is sucked from the suction port 62 of the suction unit 60 adjacent to the slit 58 and collected through the flow path 64. By providing the suction unit 60 separately from the second plate 56, in the space 66 formed between the adjacent suction units 60, the uniformization by the diffusion of the gas is further promoted, the gas flow is stabilized, and the processing unevenness is achieved. Can be eliminated.

  The present invention is not limited to the above embodiments, but can be implemented in various modes. For example, the processing may be performed in an open system without the housing 12 and the atmospheric gas supply unit 14. Instead of moving the workpiece 70 during the processing, the electrode side (the processing units 30, 31, 40, and 50) may be moved, or both may be moved. Further, if the object 70 is diffused widely widely as shown in FIGS. 3 and 4, the processing may be performed in a state where both the object 70 and the electrode are stationary.

Schematic diagram showing the basic configuration of the plasma surface treatment apparatus of the present invention Schematic diagram of a plasma surface treatment apparatus showing a first embodiment of the present invention. Schematic diagram of a plasma surface treatment apparatus showing a second embodiment of the present invention. Schematic diagram of a plasma surface treatment apparatus showing a third embodiment of the present invention. Profile diagram showing the result of comparing the configurations of FIG. 1 and FIG. Profile diagram showing the result of comparing the configurations of FIG. 1 and FIG. Main part sectional view of a plasma surface treatment apparatus showing a fourth embodiment of the present invention. The top view of the 1st plate of FIG. The top view of the 2nd plate of FIG. Main part sectional view showing a first modification of the fourth embodiment of the present invention. Main part sectional view showing a second modification of the fourth embodiment of the present invention. Main part sectional view showing a third modification of the fourth embodiment of the present invention.

Explanation of reference numerals

10, 10s, 10t Plasma surface treatment apparatus 20, 22 Electrode 24 Flow path 30, 31 Processing unit 32, 33 Space (diffusion unit)
34 aperture 36, 37 opening 40 processing section 42 first space (diffusion section)
43 Communication hole (throttle section)
44 Second space (second diffusion unit)
46 Opening 50,50s Processing part 53 Groove with bottom (diffusion part)
54 slit (aperture part)
57 Groove with bottom (second diffusion part)
58, 58s slit (aperture)
59 Through hole (suction part)
Reference numeral 60: suction unit 70: object to be processed 71r: ridge 72r: concave groove

Claims (17)

A first step of flowing gas through a flow path provided between the opposed electrodes;
A second step of discharging between the electrodes and activating the gas flowing through the flow path;
A third step of splitting or expanding the flow of the activated gas to decelerate and promote the diffusion of the gas;
And a fourth step of spraying the gas, which has promoted diffusion, onto the object to be processed. 2. The plasma surface treatment method according to claim 1, wherein, in the fourth step, the gas having promoted diffusion is blown only to the object. 3. The plasma surface treatment method according to claim 1, wherein, in the fourth step, the gas whose diffusion has been promoted is sprayed onto the object from a plurality of locations. 4. 4. The plasma surface according to claim 1, wherein in the fourth step, the flow of the gas decelerated in the third step is throttled, and the gas is accelerated and sprayed on the workpiece. 5. Processing method. The plasma surface treatment according to any one of claims 1 to 4, wherein in the third step, the speed of the decelerated gas is increased, and then the speed is reduced again to further promote the diffusion of the gas. Method. A fifth step of sucking and recovering the gas sprayed on the object from around the spray position,
In the fourth step, the gas is blown onto the object from a plurality of openings extending in parallel,
6. The method according to claim 1, wherein, in the fifth step, the gas blown to the object is suctioned and collected from a plurality of suction units extending in parallel with the openings. 7. The plasma surface treatment method according to claim 1. 7. The plasma surface treatment method according to claim 1, wherein the gas activated by the discharge between the electrodes includes 90% by volume or more of a nitrogen gas. 8. 8. The plasma surface treatment method according to claim 1, wherein each of the steps is performed in an environment at or near atmospheric pressure. A gas flows through a flow path provided between opposed electrodes, and after the gas passing through the flow path is activated by discharge between the electrodes, the gas is sprayed onto the processing object from an opening facing the processing object, plasma In the surface treatment equipment,
A plasma surface, comprising: a diffusion part that communicates the flow path and the opening, and that divides or expands the flow of the gas from the flow path to reduce and decelerate the flow of the gas. Processing equipment. The plasma surface treatment apparatus according to claim 9, wherein the opening faces only the object to be processed. The plasma surface treatment apparatus according to claim 9, wherein one of the flow paths communicates with the plurality of openings through the diffusion unit. The plasma surface treatment apparatus according to claim 9, wherein the diffusion unit is formed continuously with the opening. A throttle having a reduced cross section is provided between the diffusion unit and the opening, and the speed of the gas from the diffusion unit is increased, and the gas is ejected from the opening to the workpiece. Item 13. The plasma surface treatment apparatus according to any one of Items 9 to 12. Between the diffuser and the opening,
A throttle unit communicating with the diffusion unit and reducing the flow of the gas from the diffusion unit;
14. The device according to claim 9, further comprising: a second diffusion unit that communicates the throttle unit and the opening and expands the flow of the gas from the throttle unit. 15. The plasma surface treatment apparatus as described in the above. A plurality of said openings extending in parallel;
Around the opening, comprising a plurality of suction portions extending in parallel with the opening alternately,
The plasma surface treatment apparatus according to any one of claims 9 to 14, wherein the gas blown from the opening is suctioned and collected from the suction unit. The plasma surface treatment apparatus according to any one of claims 9 to 15, wherein the gas activated by the discharge between the electrodes includes 90% by volume or more of a nitrogen gas. 17. The plasma surface treatment apparatus according to claim 9, wherein the object is disposed in an environment at or near atmospheric pressure.

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