JP2004006586A - Plasma processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a processing gas flow uniform along the lengths of a couple of electrodes in a plasma processing apparatus which introduces the processing gas into between opposite surfaces of the electrodes from their length-side edges. <P>SOLUTION: In a gas introducing device 11 of the plasma gas processing apparatus S1, a couple of pipes 41 and 42 (uniformizing path) are provided which gradually leak nearly half portions of the processing gas flow to an upper-side first stage chamber 11a while making them flow opposite each other along the lengths of electrodes 20. The gas leaking to the chamber 11a passes through narrow gaps 11c (communication path) on both right and left sides of the pipes 41 and 42 therefrom to flow to a lower-side second stage chamber and a final-stage chamber 11b. Then the gas is introduced in a space 20a between the electrodes 20 through an intake hole 10a. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plasma processing apparatus, and in particular, generates a plasma by introducing a processing gas from between longitudinal edges of a pair of parallel long electrodes to generate plasma, forming a thin film, etching, and forming a surface. The present invention relates to an apparatus for performing surface treatment such as modification, removal of organic contaminants, water repellency or hydrophilicity.
[0002]
[Prior art]
Various methods for manufacturing semiconductor devices by forming a thin film on a substrate to be processed by a chemical vapor deposition (CVD) method or the like have been developed. However, the uniformity of the flux and concentration of the reaction gas flow may affect the thin film formation. Is known to have an effect. The effect is particularly large for large-area substrates. As a method of making the gas flow uniform, for example, a gas is passed through a porous material or a porous plate that spreads in a planar shape (Japanese Patent Application Laid-Open Nos. 6-2149 and 8-209349). However, when the gas blowout portion is elongated, it is not possible to sufficiently uniform the gas blowout portion along the longitudinal direction with only the porous member as described above.
[0003]
Therefore, Japanese Patent Application Laid-Open No. 11-236676 discloses that a gas receiving port is formed at one end in the longitudinal direction of a rectangular cylindrical gas blowing nozzle, and a diagonal swash plate is provided inside from one end to the other end. It has been proposed that the flow path is gradually narrowed along the gas flow direction, and that a large number of small nozzle outlets are arranged in the longitudinal and width directions on the longitudinal side plate of the nozzle. Thereby, the gas blown out from each nozzle blowout hole can be made to have substantially the same flow rate, and the film thickness can be made uniform.
[0004]
[Problems to be solved by the invention]
However, in order to produce higher quality products, a more uniform gas flow is required.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a plasma processing apparatus according to the present invention includes a pair of electrodes in which one surface having a longitudinal side edge is opposed to each other in parallel with each other, a processing gas source, and a processing gas source. A gas introducing device for guiding the processing gas from between the longitudinal edges of the pair of electrodes to between the opposing surfaces, and a process from the introducing device by applying an electric field between the electrodes to cause, for example, a glow discharge or the like. Electric field applying means for converting a gas into a plasma (including a radical state as well as an ionic state) between the opposed surfaces, wherein the gas introducing device is configured to divide approximately half of the processing gas flow into a longitudinal side edge of the electrode. A pair of uniformized paths that gradually leak out of the road from substantially the entire length of the peripheral side while flowing so as to face each other along a parallel direction, and one or more for each step, each having an elongated shape along the parallel direction and of A plurality of equalizing chambers communicated by passages, wherein the first equalizing chamber constitutes an off-road space of the pair of equalizing paths, and each communication passage is a front and rear stage to be communicated. In the form of a slit or a plurality of spots extending over substantially the entire length of the homogenizing chamber, the final stage homogenizing chamber is provided with a processing gas introduction hole facing substantially the entire length between the longitudinal side edges of the electrodes. It is characterized by having. As a result, the processing gas flow can be sufficiently uniformized in the direction along the longitudinal side edge of the electrode, and thus the variation in the surface treatment can be reliably eliminated.
[0006]
The gas introduction device is configured such that members forming the pair of equalizing paths are housed in the elongated device main body along the parallel direction so as to bridge in the parallel direction. The inside of the device main body on the opposite side of the electrode with respect to the electrode is provided as the first-stage homogenizing chamber, and the inside of the device main body on the electrode side is provided as the second-stage and final-stage homogenizing chamber. Furthermore, it is desirable that the gaps on both sides of the apparatus main body and the uniformizing path constituting member along the direction in which the electrodes face each other are narrowed and provided as the communication paths. As a result, the processing gas flows out of the homogenizing path to the side opposite to the electrode and then to the electrode side, so that the strength of the flow can be more reliably leveled. In addition, the component for uniformizing path can be used also as a component for the uniformizing chamber and the communication path, and the number of components can be reduced.
[0007]
The member forming the pair of equalizing paths includes a pair of pipes extending in the parallel direction and arranged side by side in a direction opposite to each other with respect to the electrodes. Desirably, a leak hole leading to the eye homogenization chamber is formed. This makes it possible to easily configure the equalizing path with a minimum number of parts.
[0008]
It is desirable that the cross-sectional area of the flow path of the uniformizing path is gradually reduced along the flow direction of the processing gas. This makes it possible to keep the internal pressure of the equalizing passage substantially constant irrespective of the leakage to the outside of the passage (first stage chamber), and to keep the flow rate of gas leaking from the leak hole to the first stage chamber substantially constant. can do.
[0009]
It is desirable that the processing gas be repeatedly split and merged, bend a plurality of times, and then be guided to the uniformizing path. Thereby, the gas can be made more uniform.
[0010]
The gas introduction device and an electrode holder that supports the pair of electrodes are integrally connected, and between the longitudinal edges opposite to the introduction device on the opposing surfaces of the pair of electrodes, the plasma is formed. It is desirable that the processing gas is a blowing hole for blowing the processing gas to the processing object. This makes it possible to configure a remote type plasma processing apparatus, to prevent the object to be processed from being directly exposed to the high electric field space, and to reduce the electrical and thermal load.
[0011]
As the material of the electrode of the present invention, a simple metal such as copper or aluminum, an alloy such as stainless steel or brass, an intermetallic compound, or the like can be used.
At least one opposing surface of the electrode is coated with a solid dielectric layer. This solid dielectric layer preferably has a thickness of 0.01 to 4 mm. If it is too thick, a high voltage may be required to generate discharge plasma, and if it is too thin, dielectric breakdown may occur when a voltage is applied, and arc discharge may occur.
Examples of the material of the solid dielectric layer include plastics such as polytetrafluoroethylene and polyethylene terephthalate, glass, metal oxides such as silicon dioxide, aluminum oxide, zirconium dioxide, and titanium dioxide, and double oxides such as barium titanate or the like. And the like can be used.
The relative dielectric constant of the solid dielectric layer is preferably 2 or more (under a 25 ° C. environment, the same applies hereinafter). Examples of such a dielectric include polytetrafluoroethylene, glass, and metal oxide. In order to stably generate high-density discharge plasma, it is preferable to use a solid dielectric having a relative dielectric constant of 10 or more. Although the upper limit of the relative dielectric constant is not particularly limited, about 18,500 of actual materials are known. Specific examples of the solid dielectric having a relative dielectric constant of 10 or more include a metal oxide mixed with 5 to 50% by weight of titanium oxide and 50 to 95% by weight of aluminum oxide, or a metal oxide containing zirconium oxide. Are preferred.
The distance between the electrodes is appropriately determined in consideration of the thickness of the solid dielectric, the magnitude of the applied voltage, the content of the plasma treatment, and the like, and is preferably 0.1 to 50 mm, more preferably 5 mm or less. preferable. If it exceeds 50 mm, it is difficult to generate uniform discharge plasma. In particular, in a direct type plasma processing apparatus in which an object to be processed is arranged between electrodes, 0.5 to 2 mm is preferable, and in a remote type plasma processing apparatus, 0.1 to 2 mm is preferable.
[0012]
In the present invention, plasma is generated by causing glow discharge, arc discharge, or the like between the electrodes, but the type of discharge is not limited. In order to maintain a high-density plasma state, glow discharge is preferable.
In the present invention, an electric field such as a high frequency wave, a pulse wave, or a microwave is applied between the electrodes to generate a plasma. Among them, it is preferable to apply a pulsed electric field, and particularly, a rise and / or fall time of a pulse. However, it is preferably 10 μs or less. If the time exceeds 10 μs, the discharge state easily shifts to an arc and becomes unstable, making it difficult to maintain a high-density plasma state. Further, the shorter the rise time and the fall time, the more efficiently the gas is ionized at the time of plasma generation, but it is actually difficult to realize a pulse electric field having a rise time of less than 40 ns. More preferably, it is 50 ns to 5 μs. Here, the rise time refers to the time during which the voltage (absolute value) continuously increases, and the fall time refers to the time during which the voltage (absolute value) continuously decreases.
[0013]
The electric field strength of the pulse electric field is preferably set to 10 to 1000 kV / cm, more preferably 15 to 1000 kV / cm. If the electric field strength is less than 10 kV / cm, it takes too much time for the treatment, and if the electric field strength exceeds 1000 kV / cm, arc discharge tends to occur.
The frequency of the pulse electric field is preferably 0.5 kHz or more. When the frequency is less than 0.5 kHz, the plasma density is low and the processing takes too long. Although the upper limit is not particularly limited, a high frequency band such as 13.56 MHz commonly used or 500 MHz used experimentally may be used. Considering the easiness of matching with the load and the handling, the frequency is preferably 500 kHz or less. By applying such a pulsed electric field, the processing speed can be greatly improved.
The duration of one pulse in the pulse electric field is preferably 200 μs or less. If the time exceeds 200 μs, the transition to arc discharge becomes easy. Here, one pulse duration refers to a continuous ON time of one pulse in a pulse electric field composed of repetition of ON and OFF.
The off time of the pulse in the pulse electric field is preferably 0.5 to 1000 μs, more preferably 0.5 to 500 μs. If it exceeds 1000 μs, the transition to arc discharge becomes easy.
[0014]
Although the plasma processing apparatus of the present invention can be used under any pressure, the effect can be sufficiently exerted particularly when used under a pressure near atmospheric pressure (under normal pressure). The pressure near the atmospheric pressure is 1.333 × 10 ⁴ ~ 10.664 × 10 ⁴ It indicates the range of Pa. Above all, 9.331 × 10 ⁴ ~ 10.297 × 10 ⁴ The range of Pa is preferable because the pressure can be easily adjusted and the apparatus can be simplified. It is known that under a pressure near the atmospheric pressure, except for a specific gas such as helium, ketone, etc., the plasma state is not stably maintained and easily transitions to arc discharge, but the applied electric field is pulsed. Thus, the discharge can be stopped before the transition to the arc discharge.
According to the atmospheric pressure discharge plasma processing apparatus using the above-mentioned pulse electric field, it is possible to cause a discharge between the electrodes under the atmospheric pressure without depending on the kind of gas at all. Processing can be realized.
[0015]
Substrates to be treated in the present invention (substrates to be treated) include plastics such as polyethylene, polypropylene, polystyrene, polycarbonate, polyethylene terephthalate, polytetrafluoroethylene, epoxy resin, liquid crystal polymer, acrylic resin, glass, ceramic, and silicon wafer. , Metals and the like. Examples of the shape of the substrate include, but are not limited to, a plate shape and a film shape.
[0016]
The processing gas used in the present invention is not particularly limited as long as it generates a plasma by applying an electric field, and various gases can be used depending on the processing purpose. According to the device of the present invention, it is possible to generate glow discharge plasma regardless of the type of gas present in the plasma generation space, and in an open system or a low airtight system that prevents free gas loss. Processing becomes possible.
CF as processing gas ₄ , C ₂ F ₆ , CCIF ₃ , SF ₆ By using a fluorine-containing compound gas such as that described above, a water-repellent surface can be obtained.
O as the processing gas ₂ , O ₃ , Water, air and other oxygen-containing compounds, N ₂ , NH ₃ Nitrogen-containing compounds such as SO ₂ , SO ₃ By using a sulfur element-containing compound such as the above, a hydrophilic functional group such as a carbonyl group, a hydroxyl group or an amino group can be formed on the surface of the base material to increase the surface energy and obtain a hydrophilic surface. Further, the hydrophilic polymer film can be coated with a polymerizable monomer having a hydrophilic group such as acrylic acid and methacrylic acid.
By using a processing gas such as a metal-hydrogen compound, a metal-halogen compound, or a metal alcoholate of a metal such as Si, Ti, or Sn, SiO ₂ , TiO ₂ , SnO ₂ And the like, and an electrical and optical function can be given to the substrate surface.
Further, etching and dicing are performed using a halogen-based gas, resist processing and organic contamination are removed using an oxygen-based gas, and surface cleaning and surface modification are performed using an inert gas such as argon or nitrogen. You can also do quality.
[0017]
From the viewpoint of economy and safety, it is preferable to perform the treatment in an atmosphere diluted with the following diluent gas, rather than in the atmosphere of the treatment gas alone. Examples of the diluting gas include rare gases such as helium, neon, argon, and xenon, and nitrogen gas. These may be used alone or in combination of two or more.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a remote type plasma processing apparatus S1 according to the first embodiment of the present invention. The plasma processing apparatus S1 includes a mounting table 2 on which a large-area work (substrate, workpiece) W is mounted, and a plasma nozzle head 10 supported on a frame (not shown) so as to be positioned on the mounting table 2. And A moving mechanism 3 is integrally connected to the mounting table 2. By the moving mechanism 3, the mounting table 2 and thus the work W are relatively moved in a forward direction perpendicular to the extending direction (lateral direction) of the electrode 20, which will be described later. The mounting table 2 may be fixed, and the head 10 may be connected to the moving mechanism 3 so as to be movable.
[0019]
The plasma nozzle head 10 will be described in detail.
As shown in FIGS. 1 and 2, the nozzle head 10 includes a pair of long electrodes 20, an electrode holder 30 for holding the long electrodes 20, and a processing gas introducing device 11 disposed thereon. ing. As shown in FIGS. 1 and 3, the electrode 20 has a prismatic shape, and extends linearly and elongated in the left-right direction (the direction orthogonal to the paper surface of FIG. 1). The electrode 20 is made of, for example, a conductive material such as stainless steel. The pulse power source 1 (electric field applying means) is connected to one (for example, rear) electrode 20, and the other (for example, front) electrode 20 is grounded.
The pulse power supply 1 outputs a pulse voltage to the electrode 20. It is desirable that the rise time and / or fall time of this pulse be 10 μs or less, and the electric field strength be 10 to 1000 kV / cm.
[0020]
As shown in FIG. 1, FIG. 3, and FIG. 6, the pair of electrodes 20 are arranged parallel to each other at a small interval (for example, 2 mm). The space between the opposing surfaces (the surface of 1) of these electrodes 20 is a plasma-forming space 20a. The space 20 a has the same thickness over the entire length of the electrode 20. As described later, the processing gas is introduced into the space 20a from between the longitudinal edges on the upper side of the facing surface. This processing gas is made into plasma and then blown out to the work W below the space 20a. The opening on the lower side of the space 20a forms a blowout hole 20x. The opposite surface and the lower surface of the electrode 20 are coated with a solid dielectric layer 21 formed by spraying ceramic. The back surface (outer surface) and the upper surface of the electrode 20 opposite to the opposing surface are polished so as to be flat and perpendicular to each other. Further, inside the electrode 20, cooling refrigerant reciprocating paths 20b and 20c are formed.
[0021]
The electrode holder 30 includes a pair of front and rear angle members 31 covered by each electrode 20, a pair of front and rear side plates 33 attached to each angle member 31, and a bridge between the upper surfaces of the side plates 33 and the angle members 31. And a cover plate 32 extending in the left-right direction. The angle member 31 is made of an insulating resin such as polytetrafluoroethylene, and has an upper piece 31x and a vertical piece 31y, and is formed in an inverted L-shaped cross section. The polished surface of the electrode 20 at the right angle is attached to the lower surface of the upper portion 31x of each angle member 31 and the inner surface of the vertical portion 31y (the surface facing the front-rear center of the head 10). ing. An elongated plate-shaped support member 37 is fixed to the lower end surface of the vertical piece portion 31y by bolting. The support member 37 slightly protrudes inward from the vertical piece 31y, and the lower and outer corners of the electrode 20 are placed and supported on the protruding portion. The upper pieces 31x of the pair of angle members 31 are opposed to each other via a narrow gap 31a at equal intervals over the entire length region.
[0022]
The cover plate 32 is made of a rigid material such as steel. A slit 32a is formed in the cover plate 32 along the longitudinal direction facing left and right. The slit 32a is continuous with the space 20a between the electrodes 20 via the gap 31a between the angle members 31.
[0023]
As shown in FIGS. 1 and 2, the side plate 33 is formed in a long plate shape from a rigid material such as a steel material, and extends straight in the horizontal direction while turning the width direction up and down. The side plate 33 is addressed to the front and rear outer surfaces (back surface) of the vertical piece portion 31y of the angle member 31, and the upper edge is abutted against the cover plate 32 and is bolted.
[0024]
The electrode holder 30 is provided with an interval adjusting mechanism between the pair of electrodes 20. That is, as shown in FIGS. 1, 2, and 6, the side plate 33 is provided with a plurality of electrode pushing bolts 34 and electrode pulling bolts 35, which are separated from each other in the longitudinal direction. The push bolt 34 (access means of the interval adjusting mechanism) is screwed into the screw hole 33 a of the side plate 33, penetrates the screw hole 33 a, and is abutted against the concave portion 31 c on the back surface of the angle member 31. As a result, it comes into contact with the back surface of the electrode 20 via the angle member 31. By further screwing the push bolt 34, the electrode 20 can be pushed through the angle member 31.
[0025]
As shown in FIGS. 1 and 6, the side plate 33 and the angle member 31 are provided with a plurality of accommodation holes 33b, 31b separated from each other in the longitudinal direction. A stepped tubular pull bolt holder 36 is accommodated in these accommodation holes 33b and 31b. A flange 36 a is provided at an outer end of the bolt holder 36, and the flange 36 a contacts a step 33 c of the receiving hole 33 b of the side plate 33. The bolt holder 36 has a large-diameter hole 36b formed on the outer end side along the central axis thereof, and a small-diameter hole 36c formed on the inner end side. A pull bolt 35 is inserted into these holes 36b and 36c. The head of the pull bolt 35 abuts a step between the holes 36b and 36c, and the legs are screwed into the screw holes 20d of the electrode 20 through the small diameter holes 36c. By tightly screwing the pull bolt 35, the electrode 20 can be pulled (moved away from the other electrode 20). When the electrode 20 is to be pulled toward the other electrode side 20 by Coulomb force or the like, the head of the pull bolt 35 is caught by the step between the holes 36b and 36c of the bolt holder 36, and the flange 36a of the bolt holder 36 Is hooked on the step 33c of the side plate 33 (the head of the pulling bolt 35 is hooked on the side plate 33 via the bolt holder 36), so that the movement (distortion) is prevented.
The pull bolt 35 and the holder 36 cooperate with each other to form “separating means of the gap adjusting mechanism” and also as “inhibiting means for preventing distortion due to Coulomb force of the electrode”.
[0026]
The processing gas is introduced into the space 20 a between the electrodes 20 via the gas supply line 60 and the introduction device 11. As shown in FIG. 1, the gas supply line 60 ₄ And a tube means 62 for connecting the gas source 61 and the introducing device 11. The tube means 62 has one common tube 63 connected to the processing gas source 61 and four (plural) branch tubes 64 branched from the common tube 63. The branch tube 64 extends so as to occupy most of the length of the tube means 62. The cross-sectional area of the flow passage of each branch tube 64 is a quarter of that of the common tube 63. Therefore, each of the branch tubes 64 can be made thinner, and the drawing can be facilitated. The branch tubes 64 are merged two by two, and the merge tube 65 extends therefrom. The cross-sectional area of the flow passage of each tube 65 is twice as large as that of the branch tube 64. These tubes 65 are connected to the introduction device 11.
[0027]
The introduction device 11 will be described.
As shown in FIGS. 1 to 3, the introduction device 11 includes a device main body 12 that is elongated in the left-right direction, and an inner pipe unit 40 (uniform path constituent member) housed in the device main body 12. . The apparatus main body 12 includes a main body 13 in the shape of an elongated container having an upper surface opened, a cap plate 14 fitted into and closing the upper surface opening of the main body 13, and a top plate superimposed on the cap plate 14. 15.
[0028]
As shown in FIG. 1 to FIG. 3 and FIG. 4A, a pair of end pieces 16 are provided on the left and right ends on the upper surface of the top plate 15, and a center piece 17 is provided at the center. Between each end piece 16 and the center piece 17, two upper pipes 51, 52 extending left and right are arranged back and forth two by two. The left and right rear upper pipes 51 are arranged in a straight line with each other with the center piece 17 interposed therebetween, and the front upper pipes 52 are arranged in a straight line with each other.
[0029]
The left and right end pieces 16 are formed with gas receiving ports 16a connected to the rear upper pipe 51, respectively. One tube 65 of the gas supply line 60 is connected to the left receiving port 16a, and the other tube 65 is connected to the right receiving port 16a. As a result, the processing gas from the gas source 61 is guided from each port 16a into the upper pipe 51 and flows toward the center piece 17.
[0030]
As shown in FIG. 4A, a communication hole 17a is formed in the center piece 17 to allow the insides of the four upper pipes 51 and 52 to communicate with each other. As a result, the processing gases from the two rear upper pipes 51 merge into the holes 17a, are then guided into the two front upper pipes 52, and flow toward the left and right ends.
[0031]
As shown in FIG. 2, a pair of end blocks 18 are provided on left and right end plates of the main body 13. The end block 18 is abutted on the lower surface of the end piece 16. As shown in FIGS. 1 and 3 to 5, the left and right end pieces 16 and the end block 18 are formed with a bent path 12 a extending from the upper pipe 52. That is, as shown in FIG. 3 and FIG. 4A, the end piece 16 has a path 16 b which is linearly connected to the inside of the front upper pipe 52, and a path extending downward from the path 16 b and reaching the lower surface of the end piece 16. 16c are formed. As shown in FIGS. 3 and 4B, an oval concave portion extending in the front-rear direction is formed on the upper surface of the end block 18, and the path 12 b is formed by the oval concave portion and the lower surface of the end piece 16. Have been. The road 16c is connected to the front end of the road 12b. As shown in FIGS. 3 and 4B and 4C, the end block 18 has a path 18b extending downward from the rear end of the path 12b. As shown in FIG. 3 and FIG. 5A, the left end block 18 is formed with a path 18c extending forward from the lower end of the path 18b. On the other hand, the right end block 18 has a path 18c 'extending rearward from the lower end of the path 18b. As described later, these left and right paths 18c, 18c 'are respectively connected to pipes 41, 42 before and after the inner pipe unit 40.
[0032]
The inner pipe unit 40 will be described.
As shown in FIG. 1, FIG. 3, and FIG. 5A, the unit 40 includes two inner pipes (uniform paths) 41, 42 extending left and right and arranged in front of each other, and the inner pipes 41, 42. Holding plates 43 and 44 for sandwiching 42 from above and below. Left and right ends of the inner pipes 41 and 42 are supported by left and right end plates of the main body 13. As shown in FIGS. 3 and 5A, the left end of the front inner pipe 41 is connected to the path 18 c of the left end block 18. On the other hand, the right end of the front inner pipe 41 is closed. As shown in FIG. 5A, the right end of the rear inner pipe 42 continues to the path 18c 'of the right end block 18, and the left end is closed.
[0033]
As shown in FIG. 1, FIG. 3 and FIG. 5A, small leak holes 41a and 42b penetrating from the inner peripheral surface to the outer peripheral surface are formed on the upper portions of the inner pipes 41 and 42 in the circumferential direction. , 42 are formed at short intervals over substantially the entire length area.
[0034]
As shown in FIG. 1, the upper and lower holding plates 43 and 44 straddle between the front and rear inner pipes 41 and 42, respectively. These holding plates 43 and 44 are connected by bolts 45 passed between the inner pipes 41 and 42, and thus hold the inner pipes 41 and 42. As shown in FIGS. 1, 3, and 4 (c), the upper sandwiching plate 43 has a large number of leak holes 43 a connected to the holes 41 a, 42 a of the inner pipes 41, 42. These leak holes 43a are opened on the upper surface of the holding plate 43.
[0035]
As shown in FIGS. 1 and 3, between the cap plate 14 and the upper holding plate 43 of the apparatus main body 12, an upper chamber (a first-stage uniform chamber) 11 a that is elongated in the left and right directions is formed. The hole 43a of the holding plate 43 and the leak holes 41a and 42a of the inner pipes 41 and 42 are connected to the chamber 11a.
[0036]
As shown in FIGS. 1, 4C and 5A, gaps 11c (communication passages) are formed between the front and rear side walls of the main body 13 and the inner pipes 41 and 42, respectively. . The gap 11c has the same thickness and is very narrow over the entire length of the inner pipes 4 and 42.
[0037]
As shown in FIGS. 1, 3 and 5 (b), between the lower holding plate 44 and the bottom plate of the main body 13, a lower left and right elongated lower chamber (uniformization of the second and final stages). A chamber 11b is formed. The lower chamber 11b is connected to the upper chamber 11a via a gap 11c.
[0038]
As shown in FIGS. 1 and 5 (b), a slot 13a is formed at the center of the bottom plate of the main body 13 in the width direction (front-back direction) so as to extend over the entire left and right direction. The groove 13a is wider on the upper surface of the bottom plate of the main body 13 and becomes narrower toward the lower surface. The hole 13a is connected to the plasma space 20a between the pair of electrodes 20 via the slit 32a and the gap 31a of the electrode holder 30. The holes 13a, the slits 32a, and the gaps 31a form holes 10a for introducing the processing gas into the plasma generating space 20a.
[0039]
The operation of the plasma processing apparatus S1 configured as described above will be described.
The processing gas from the gas source 61 passes through the common tube 63 and is divided into four by the branch tube 64, and then flows into the two tubes 65 by merging two each. After passing through these tubes 65, they are introduced into the left and right ports 16a of the nozzle head 10 and flow through the left and right rear upper pipes 51 toward the center of the device 11, respectively. Then, after merging into one in the communication hole 17 a of the center piece 17, the flow is divided into approximately half, guided to the left and right front upper pipes 52, and flows toward the left and right ends. Furthermore, it is bent at right angles a plurality of times on the left and right bending paths 12a. As described above, the processing gas flow can be leveled by repeating the branching, merging, and bending.
[0040]
The processing gas flows after passing through the left and right bent paths 12a are sent into the inner pipes 41 and 42, respectively. The processing gas entering the front inner pipe 41 from the left bent path 12a flows to the right inside the pipe 41, passes through the leak holes 41a, 43a arranged in this flow direction, and the upper chamber 11a (outside the uniform path). Leaks gradually to. Similarly, the processing gas entering the rear inner pipe 42 from the right bent path 12a gradually flows to the upper chamber 11a (outside the uniform path) through the leak holes 42a and 43a while flowing inside the pipe 42 to the left. Get out. At this time, in each of the pipes 42, the flow rate and the flow velocity of the processing gas gradually change along the flow. However, the above-mentioned tendency is canceled by mutually flowing the processing gas through the two pipes 42. Can be. Thereby, the processing gas can be substantially uniformly introduced into the upper chamber 11a in the left-right direction. Since the upper chamber 11a has a sufficiently large volume, the processing gas can be temporarily set to a static pressure in the chamber 11a.
[0041]
Further, the processing gas flows from the entire length of the upper chamber 11a to the lower chamber 11b through the narrow gap 11c. At this time, a pressure loss occurs in the gap 11c, and the gas having a high pressure tends to flow into a lower pressure. Thereby, the gas flow can be sent to the lower chamber 11b with more uniformity in the left-right direction. The processing gas becomes static pressure again in the chamber 11a. Then, it is guided from the chamber 11b to the introduction hole 10a. Thereby, a uniform processing gas flow in the left-right longitudinal direction can be introduced into the space 20a between the opposing surfaces from between the upper edges of the pair of electrodes 20.
[0042]
On the other hand, a pulse voltage from the pulse power supply 1 is applied between the electrodes 20, and a pulse electric field is formed in the space 20a. As a result, glow discharge occurs in the space 20a, and the processing gas is turned into plasma. Since the processing gas is made uniform in the left-right direction, the plasma can also be made uniform in the left-right direction. The uniform plasma flow is blown onto the work W from the blowout holes 20x, so that the upper surface of the work W can be subjected to a uniform surface treatment.
[0043]
In addition, even if a Coulomb attractive force acts between the electrodes 20 due to the applied electric field, the head of the pull bolt 35 screwed into the electrode 20 is hooked on the side plate 33 via the bolt holder 36, and the other electrode 20 Can be prevented from being pulled toward. Thereby, the bending of the electrodes 20 can be prevented, and the gap between the electrodes 20, that is, the thickness of the plasma-forming space 20a can be maintained uniform. As a result, the plasma flow can be more reliably and uniformly blown along the longitudinal direction of the electrode 20, and a uniform surface treatment can be performed more reliably.
[0044]
In the plasma head nozzle 10, by adjusting the push-pull bolts 34 and 35, even if the electrode 20 is distorted due to the thermal spraying process of the solid dielectric layer 21 or the polishing process of the reference surface during the manufacturing process of the electrode 20, The distortion of the electrode 20 can be eliminated, and the thickness of the plasma space 20a can be surely made uniform. As a result, the blown plasma flow can be more reliably made uniform, and a more uniform surface treatment can be performed. Further, the thickness of the space 20a can be increased to facilitate gas flow, and the thickness of the space 20a can be reduced to facilitate glow discharge.
[0045]
Next, another embodiment of the present invention will be described. In the following embodiments, the same configurations as those in the above-described embodiments are denoted by the same reference numerals in the drawings, and description thereof is omitted.
7, 8, and 9 show a remote type plasma processing apparatus S2 according to a second embodiment of the present invention. The plasma nozzle head 10 of the apparatus S2 is provided inside the apparatus body 12 in the shape of a container that is elongated on the left and right of the processing gas introduction apparatus 11, as a “uniformizing path constituent member” instead of the pipe unit 40 of the first embodiment, An inner cylinder 40X having a square cross section is accommodated. The inner cylinder 40 </ b> X extends in the same direction as the apparatus main body 12, and both ends are abutted and joined to left and right end plates of the apparatus main body 12. The left and right end plates of the apparatus main body 12 are provided with processing gas receiving ports 16a, respectively. These ports 16a are connected to the inner cylinder 40X.
[0046]
An oblique partition plate 46 extending diagonally from the front corner at the left end to the rear corner at the right end is provided inside the inner cylinder 40X. The inside of the inner cylinder 40X is partitioned by the oblique partition plate 46 into two equalizing paths 42x and 41x in front and rear, each of which forms a slender triangular shape in a plan view, which are opposite to each other. The rear equalizing path 41x is connected to the processing gas receiving port 16a on the left side at the left end, and the cross-sectional area of the flow path gradually decreases toward the right side. The front uniforming path 42x is connected to the processing gas receiving port 16a on the right side at the right end, and the cross-sectional area of the flow path gradually decreases toward the left side.
[0047]
Many small leak holes 40a are formed in the entire upper plate of the inner cylinder 40X so as to be aligned in the left-right longitudinal direction and the front-rear width direction. Through these leak holes 40a, two equalizing paths 42x and 41x are connected to the chamber 11a above the inner cylinder 40X.
The gap 11c between the front and rear side plates of the apparatus body 12 and the inner cylinder 40X has a vertical length corresponding to the height of the inner cylinder 40X.
[0048]
According to the second embodiment, the processing gas is sent from the left and right ports 16a into the paths 41x and 42x, and sequentially leaks from the leak holes 40a into the upper chamber 11a. At this time, since the cross-sectional area of each of the passages 41x and 42x is gradually reduced along the flow direction of the processing gas, the internal pressure of each of the passages 41x and 42x can be kept substantially constant, and the leak hole 40a can be maintained. The flow rate of gas leaking from the upper chamber 11a to the upper chamber 11a can be kept substantially constant. The processing gas that has reached the upper chamber 11a then passes through the gap 11c. Since the gap 11c is vertically elongated by the height of the inner cylinder 40X, a pressure loss can be reliably generated, and the gas flow can be more reliably uniformized in the left-right longitudinal direction. The uniformized processing gas is introduced into the space 20a between the electrodes 20 from the introduction hole 10a through the chamber 11b below the inner cylinder 40X, and is blown onto the work W as a plasma flow.
[0049]
FIGS. 10 and 11 show a direct plasma processing apparatus S3 according to a third embodiment of the present invention. In this embodiment, a pair of electrodes 20 are separated from the nozzle head 10 and have a parallel plate shape facing vertically. A work W in the form of a film is interposed between the electrodes 20, for example, and is sequentially fed forward (to the right in FIG. 10) by the roll-type moving mechanism 3X. In the processing gas introduction device main body 12 of the nozzle head 10, a processing gas introduction hole 10a (blow-out hole) is arranged at the bottom rear corner facing the electrode 20 so as to face the diagonally lower interelectrode space 20a. I have.
[0050]
The present invention is not limited to the above embodiment, and various modifications are possible.
For example, the homogenizing chamber is not limited to two stages, and may be provided in three or more stages.
The leak hole of the equalizing path may have a continuous slit shape over substantially the entire length of the equalizing component.
A large number of the processing gas introduction holes 10a may be arranged in the longitudinal direction of the electrode 20 in a small hole shape.
The communication paths communicating the equalization chambers at the front and rear stages may be formed in small holes (spots) and arranged at equal pitches in the longitudinal direction of these chambers.
[0051]
【Example】
An embodiment of the present invention will be described.
Example 1
(1) Process gas introduction
Using the apparatus S2 shown in FIGS. 7 to 9, the flow velocity distribution when the processing gas was sent into the plasma-forming space 20a was measured. As the main body 12 of the processing gas introduction device 11, a box-shaped body having a front and rear width of 32 mm, a height of 75 mm and a left and right length of 230 mm was prepared. Inside the apparatus main body 12, an inner cylinder 40X measuring 30 mm in front and rear width × 30 mm in height × 230 mm in left and right length was installed. The inside of the cylinder 40X is divided obliquely by a partition plate 46 to form two opposed flow paths 41x and 42x, each of which is connected to a 7 mmφ circular processing gas receiving port 16a. As the upper plate of the inner cylinder 40X, a perforated plate in which 22 1 mmφ leak holes 40a were opened in four rows was used. The distance between this and the upper plate of the apparatus body 12, that is, the vertical height of the upper chamber 11a was 30 mm. The thickness of the gap 11c is 1 mm, and the vertical height of the lower chamber 11b is 15 mm. A slit-shaped introduction hole 10a having a height of 5 mm and a width of 2 mm was formed at the bottom of the apparatus body 12.
As processing gas, dry air was sent from the left and right ports 16a to the equalizing paths 41x and 42x, respectively, at 10 L / min, for a total of 20 L / min. Then, the flow velocity was measured at 11 locations at intervals of 20 mm along the longitudinal direction of the introduction hole 10a.
As a result, the variation of the flow rate was ± 2.0%. Here, the flow velocity variation was determined by the following equation.
Flow velocity variation = (maximum flow velocity-minimum flow velocity) / average flow velocity
[0052]
(2) Discharge plasma treatment
Next, a pair of electrodes 20 is attached to the lower side of the processing gas introducing device 11 of the above (1), a processing gas is introduced into the inter-electrode space 20a, and the plasma is formed by turning the workpiece W into a plasma. Was performed. A 25 mm × 20 mm × 240 mm SUS rod was used as the electrode 20, and alumina was sprayed on the surface to a thickness of 1 mm. The distance between the pair of electrodes 20, that is, the thickness of the plasma forming space 20a was 2 mm. An 8-inch silicon wafer was placed at a distance of 2 mm from the outlet 20x. As the processing gas, a mixture of oxygen 15 L / min and nitrogen 5 L / min mixed with vaporized TEOS at a rate of 0.2 g / min is supplied from the left and right ports 16 a to the equalizing paths 41 x and 42 x respectively. Sent. Then, under a pressure of 95 kPa, a pulse rising speed between the electrodes 20 is 5 μs, a frequency is 5 kHz, and V _PP = 20 kV, the head 10 was moved at 100 mm / min, and SiO 2 was placed on the work W made of an 8-inch silicon wafer. ₂ A film was formed.
Obtained SiO ₂ When the thickness of the film was measured at 600 points using an ellipsometer, the variation in the film thickness was ± 3.2%. Here, the film thickness variation was determined by the following equation.
Film thickness variation = (film thickness maximum value-film thickness minimum value) / film thickness average value
[0053]
Comparative Example 1
As a comparative example, a processing gas introduction device 11 'shown in FIGS. 12 and 13 was prepared. The size of the box-shaped main body 12 of the introduction device 11 ′ is 32 mm in front and rear width × 75 mm in height × 230 mm in left and right length, one processing gas receiving port 16 a is arranged only on the left end plate, and the oblique partition plate 46 is The main body 12 was provided so as to be inclined downward from the upper left corner to the right. The right end of the diagonal partition plate 46 was positioned 28 mm below the upper plate of the main body 12, and a horizontal plate 47 was provided at the same height as this. As the horizontal plate 47, a perforated plate in which 22 1 mmφ leak holes 47a were opened in four rows was used. 28 mm below the horizontal plate 47, a baffle plate 48 is horizontally spanned between the left and right end plates of the apparatus main body 12, and the space between the baffle plate 48 and the horizontal plate 37 is defined as an upper chamber 11a. The lower chamber 11b was defined as the space between the lower chamber 12 and the bottom plate 12. A 1 mm wide gap 11c was formed between the front and rear side edges of the baffle plate 48 and the front and rear side plates of the apparatus main body 12. In the bottom plate of the apparatus main body 12, a slit-like introduction hole 10a having a height of 5 mm and a width of 2 mm was formed.
As a processing gas, 20 L / min of dry air was sent from the port 16a to the single homogenizing path 41x. Then, as in Example 1 (1), the flow velocity was measured at 11 locations at intervals of 20 mm along the longitudinal direction of the introduction hole 10a.
As a result, the variation of the flow rate was ± 5.2%.
Next, a plasma discharge treatment was performed in the same manner as in Example 1 (2). As a result, the variation in the film thickness was ± 4.5%.
[0054]
【The invention's effect】
As described above, according to the present invention, thereby, the processing gas flow can be sufficiently uniformized in the direction along the longitudinal side edge of the electrode, and thus, the dispersion of the surface treatment can be reliably eliminated.
[Brief description of the drawings]
FIG. 1 is a side sectional view of a plasma processing apparatus according to a first embodiment of the present invention.
FIG. 2 is a perspective view of a plasma head nozzle of the plasma processing apparatus.
FIG. 3 is a front sectional view of the plasma head nozzle taken along line III-III in FIG. 1;
FIG. 4 (a) is a plan sectional view of the processing gas introduction device of the plasma head nozzle taken along the line IVA-IVA of FIG. FIG. 4B is a plan cross-sectional view of the processing gas introduction device of the plasma head nozzle taken along line IVB-IVB in FIG. 1. FIG. 4C is a plan cross-sectional view of the processing gas introduction device of the plasma head nozzle taken along line IVC-IVC in FIG. 1.
5 (a) is a plan sectional view of the processing gas introduction device of the plasma head nozzle taken along the line VA-VA of FIG. 1; FIG. 2B is a plan cross-sectional view of the processing gas introduction device of the plasma head nozzle taken along line VB-VB in FIG. 1.
FIG. 6 is a plan sectional view of an electrode holder of the plasma head nozzle taken along line VI-VI in FIG. 1;
FIG. 7 is a perspective view schematically showing a plasma nozzle head of a plasma processing apparatus according to a second embodiment of the present invention.
8 is a side sectional view of the gas introduction device of the plasma nozzle head according to the second embodiment, taken along line VIII-VIII in FIG. 7;
FIG. 9 is a plan sectional view of the gas introduction device of the second embodiment, taken along line IX-IX in FIG. 7;
FIG. 10 is a side sectional view schematically showing a plasma processing apparatus according to a third embodiment of the present invention.
FIG. 11 is a perspective view schematically showing a gas introduction device of the plasma processing apparatus according to the third embodiment.
FIG. 12 is a perspective view schematically showing a gas introduction device used in a comparative example.
FIG. 13 is a side sectional view of the comparative example device, taken along line XIII-XIII of FIG.
[Explanation of symbols]
W Work (object to be processed)
S1 to S3 Plasma processing device
1 pulse power supply (electric field application means)
10 Plasma nozzle head
10a Gas inlet
11 Process gas introduction device
11a Upper chamber (first chamber)
11b Lower chamber (2nd and final chamber)
11c Clearance (communication passage)
12 Main unit
20 long electrodes
20a Plasma conversion space (space between opposing surfaces of electrodes)
20x outlet
30 electrode holder
40 Inner pipe unit (uniform road component)
40X inner cylinder (uniform road component)
40a leak hole
41 Front inner pipe (equalizing path)
41a, 42a, 43a Leakage hole
41x, 42x equalization path
42 Rear inner pipe (Equalizing path)
46 Diagonal partition
60 Processing gas source

Claims (6)

A pair of electrodes whose longitudinal sides are parallel to each other and facing each other, a processing gas source, and a processing gas from the processing gas source facing the longitudinal surfaces of the pair of electrodes between the longitudinal sides. A gas introduction device that guides between the electrodes, and an electric field application unit that converts the processing gas from the introduction device into plasma between the facing surfaces by applying an electric field between the electrodes,
A pair of the gas introducing device, which gradually leaks from the substantially full length area of the peripheral side portion to the outside while flowing approximately half of the processing gas flow so as to face each other along a direction parallel to the longitudinal side edge of the electrode. A uniformizing path, having a plurality of equalizing chambers each having an elongated shape along the parallel direction and communicating with one or more communication paths for each stage,
The first-stage equalization chamber forms an off-road space of the pair of equalization paths,
Each communication passage has a slit shape or a plurality of spot shapes covering substantially the entire length of the equalization chamber of the stage before and after the communication,
A plasma processing apparatus, characterized in that a processing gas introduction hole is provided in a final stage of the homogenization chamber and extends substantially over the entire length region between the longitudinal side edges of the electrode. The gas introduction device is housed inside the elongated device main body along the parallel direction so as to bridge the members forming the pair of equalization paths in the parallel direction,
The inside of the device main body on the opposite side of the electrode with respect to the uniformizing path constituting member is provided as the first stage homogenizing chamber, and the inside of the device main body on the electrode side is the second stage and the final stage. Further, the gap on both sides along the direction in which the electrodes of the apparatus body and the equalizing path constituting member face each other is narrowed and provided as the communication path. The plasma processing apparatus according to claim 1. The member forming the pair of equalizing paths includes a pair of pipes extending in the parallel direction and arranged side by side in a direction opposite to each other, and the first stage is provided in a substantially entire length of a pipe wall of each pipe. 3. The plasma processing apparatus according to claim 1, wherein a leak hole communicating with the eye uniforming chamber is formed. The plasma processing apparatus according to any one of claims 1 to 3, wherein a flow path cross-sectional area of the uniformizing path is gradually reduced along a gas flow direction. The plasma processing apparatus according to any one of claims 1 to 4, wherein the processing gas is repeatedly split and merged, further bent a plurality of times, and then guided to the equalizing path. . The gas introduction device and an electrode holder that supports the pair of electrodes are integrally connected, and between the longitudinal edges on the opposite surfaces of the pair of electrodes opposite to the introduction device, the plasma is formed. The plasma processing apparatus according to any one of claims 1 to 5, wherein the processing gas is a blowout hole for blowing a processing gas to a processing object.

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