JP3832568B2 - Intermediate electrode structure of pressure gradient plasma generator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intermediate electrode structure of a pressure gradient type plasma generator used in a vacuum film forming apparatus.
[0002]
[Prior art]
Conventionally, for example, an ion plating apparatus 10 as shown in FIG. 8 is known as a vacuum film forming apparatus using a pressure gradient type plasma generator. In this ion plating apparatus 10, a pressure gradient type plasma generator 20 is attached to a vacuum vessel 11, and a coil 30 for guiding a generated plasma beam is provided on the outer periphery of the pressure gradient type plasma generator 20. It is arranged. The pressure gradient type plasma generator 20 is provided with a first intermediate electrode 91 and a second intermediate electrode 101 for converging the plasma beam, and the first intermediate electrode 91 has an annular shape. A magnet 94 is built in, and a focusing coil 102 is built in each of the second intermediate electrodes 101.
[0003]
Inside the vacuum vessel 11, the substrate 60 is supported and disposed so as to be suspended from the ceiling, and a DC power supply for negative bias is connected to the substrate 60. A hearth (anode) 50 is disposed on the bottom surface of the vacuum vessel 11 so as to face the substrate 60, and an annular auxiliary anode 51 is disposed on the outer periphery thereof. Further, a gas introduction port 11 a for introducing a carrier gas into the vacuum vessel 11 and an exhaust port 11 b for exhausting the inside of the vacuum vessel 11 are formed on the side wall of the vacuum vessel 11.
[0004]
The pressure gradient plasma generator 20 includes a conductor plate 21 at one end, and a carrier gas (inert gas such as Ar) is introduced from a carrier gas inlet 22 formed in the conductor plate 21. ing. Further, the negative end of the variable power source 70 is connected to the conductor plate 21, and the positive end is connected to the first intermediate electrode 91 and the second intermediate electrode 101 via resistors R1 and R2, respectively. The hearth 50 is connected to the variable power source 70 and the resistors R1 and R2.
[0005]
When the carrier gas is introduced from the carrier gas inlet 22 of the pressure gradient type plasma generator 20, the ion plating apparatus 10 configured in this way starts discharge in the pressure gradient type plasma generator 20, and the plasma beam 40 Will occur. The generated plasma beam 40 is converged to a passage (orifice) in the center of the first intermediate electrode 91 and the second intermediate electrode 101 in which the annular magnet 94 and the coil 102 are incorporated, and the coil 30 and the auxiliary anode Guided by 51 magnets, it reaches the hearth 50 used as the anode and the auxiliary anode 51, and the vapor deposition material 52 accommodated in the hearth 50 is Joule-heated to evaporate. The vapor deposition metal particles from the vapor deposition material 52 thus evaporated are ionized and activated by the plasma beam 40, and the ion particles adhere to the surface of the substrate 60 to which a negative voltage is applied, and a film is formed on the substrate 60. It is like that.
[0006]
FIG. 9 is an explanatory diagram showing the first intermediate electrode 91 of the pressure gradient plasma generator 20 of the ion plating apparatus 10 in more detail, (a) is a front view, (b) is a side view, c) is a cross-sectional view taken along the line CC of (a).
[0007]
Hereinafter, the configuration of the first intermediate electrode 91 will be described with reference to FIG. 9. The first intermediate electrode 91 has a donut shape having a through-hole (orifice) 93 for converging and passing the plasma beam at the center. A magnet 94 for converging the plasma beam to pass through the orifice 93 is supported and fixed in the hollow of the case 92 having a hollow structure inside. At this time, the case 92 is welded and joined by three substantially circular seal portions 92a, 92b, and 92c along the outer shape, so that the annular magnet 94 is accommodated in the case 92. The seal portions 92a, 92b, and 92c may be screwed together with an O-ring or packing in addition to welding.
[0008]
A cooling solvent 95 is circulated in the gap between the case 92 and the magnet 94. The cooling solvent 95 is for cooling the entire intermediate electrode 91 in order to prevent the case 92 from being broken by discharge electrons, ion bombardment, heat from the cathode, or the like. As shown in the horizontal sectional view of (b), the gap between the case 92 and the magnet 94 in the intermediate electrode 91 is circulated. That is, holes 95a and 95b for piping are formed on the side surfaces of the case 92, pipes are attached to the holes 95a and 95b, and the cooling medium 95 is allowed to flow through the gap between the case 92 and the magnet 94, so that the entire intermediate electrode 91 is It has a structure that is cooled and protected from heat when plasma is generated. Reference numeral 96 shown in FIG. 9C denotes a cover that covers the vicinity of the orifice 93 of the intermediate electrode 91 so as not to directly contact the plasma beam, and is made of a metal having a low sputtering rate such as tungsten, carbon, or the like. .
[0009]
The structure of the first intermediate electrode 91 has been described as an example using the annular magnet 94. However, like the second intermediate electrode 101, a structure in which a converging magnetic field is generated using the converging coil 102 is used. Is the same. However, in the case of a structure using a coil, wiring is performed in a state in which watertightness is secured from the outside of the case. The ion plating apparatus 10 is merely an example, and there are various arrangements of the pressure gradient type plasma generator 20, the hearth 50, and the substrate 60 depending on the configuration of the apparatus. The ion plating apparatus has been described as an example, but the same applies to a vacuum film forming apparatus such as a plasma CVD apparatus using a pressure gradient type plasma generator.
[0010]
[Problems to be solved by the invention]
However, the structure of the intermediate electrode 91 of the conventional pressure gradient type plasma generator 20 has a configuration in which an annular magnet 94 or a coil is disposed in the hollow structure of the donut-shaped case 92, so that the orifice There is a problem that the cooling solvent 95 tends to stay in the vicinity of 93 and the cooling efficiency in the vicinity thereof is poor. In addition, in order to form a space as a flow path for the cooling solvent 95 between the magnet 94 and the orifice 93 in a state where the magnet 94 or the coil is housed and held in the hollow structure of the case 92, a seal portion 92a of the case 92 is formed. 92b must be formed in the vicinity of the orifice 93 because of the structure, and the vicinity of the orifice 93 becomes a converging portion of the plasma beam, so that the seal portions 92a and 92b are destroyed by discharge electrons or ion bombardment or heat from the cathode. There was a problem in durability when used over a long period of time. In particular, when combined with the problem that the cooling solvent 95 is likely to be stagnant in the vicinity of the orifice 93 described above, this is a further problem in terms of durability. Further, since the magnet 94 or the coil is placed in the cooling solvent 95 in the case 92, the state of the central magnetic field may change over time due to the magnet 94 being deteriorated and cracked by the cooling solvent 95, There is also a problem that the coil wiring is broken by corrosion, and the solution of such a problem has been an issue.
[0011]
[Means for Solving the Problems]
As a specific means for solving the above-described conventional problems, the present invention includes a case having a through-hole in the center and a hollow inside, and a plasma beam fixed to the case to converge on the through-hole. An intermediate electrode structure of a pressure gradient type plasma generator comprising: an annular magnet or coil for passing through; and a cooling solvent for circulating the inside of the case to cool the whole. The present invention solves the problem by providing an intermediate electrode structure of a pressure gradient type plasma generator characterized by having a structure in which the magnet or coil is fitted in the recess. .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in detail based on embodiments shown in the drawings.
[0013]
FIG. 1 is a cross-sectional view showing a first embodiment of an intermediate electrode structure of a pressure gradient type plasma generating apparatus according to the present invention. The entire vacuum film forming apparatus (for example, ion plating apparatus) and pressure gradient type plasma generating apparatus Since the configuration is the same as that of the conventional example (FIG. 8), description thereof is omitted here.
[0014]
The intermediate electrode 1 of the pressure gradient type plasma generator according to the present invention has a donut shape having a through-hole (orifice) 3 for converging and passing a plasma beam at the center, and a case 2 having a hollow structure inside. A magnet 4 for converging the plasma beam to pass through the orifice 3 is supported and fixed. At this time, the case 2 is welded and joined by three substantially circular seal portions 2a, 2b, and 2c along the outer shape, so that the inside of the case 2 has a hollow structure. The seal portions 2a, 2b and 2c may be welded or screwed with an O-ring or packing interposed therebetween.
[0015]
And the cooling solvent 5 distribute | circulates the hollow inside of this case 2. As shown in FIG. The cooling solvent 5 is for cooling the entire intermediate electrode 1 in order to prevent the case 2 from being destroyed by discharge electrons, ion bombardment, heat from the cathode, or the like. It is designed to circulate in the hollow.
[0016]
Although the above points are the same as those of the conventional example, in the present invention, the side surface of the case 2 has a shape recessed along the outer peripheral surface, and the magnet 4 is fitted in the recess. That is, as shown in FIG. 2A, the annular magnet 4 is divided into two parts 4a and 4b as shown in FIG. 2B, and is fixed by being fitted into a recess from the side surface of the case 2 as shown in FIG. is doing. When a coil is used instead of the magnet 4, the coil 4c is provided by laying a thin insulating sheet or the like in the recess on the side surface of the case 2 and winding a copper wire with an insulating film thereon as shown in FIG. It has been.
[0017]
By adopting the above configuration, the magnet 4 or the coil that has been conventionally housed in the case 2 and placed in the cooling solvent 5 is taken out of the case 2 (outside the flow path of the cooling solvent 5). The deterioration of the magnet 4 and the disconnection of the coil wiring can be prevented.
[0018]
Next, the flow path of the cooling solvent 5 will be described with reference to FIG. Two holes for piping that lead into the hollow of the case 2 are formed in places other than the recesses in which the magnets 4 or coils on the side surface of the case 2 are fitted, and pipes 5a and 5b are attached to the holes. First, as shown in (a), the cooling solvent 5 is introduced from the pipe 5a and flows in the direction of the arrow (1). Then, it flows into the vicinity of the orifice 3 by the partition walls 2d and 2e formed in the hollow of the case, and flows in the direction of (2) along the orifice 3 as shown in FIG. Flow into. Then, it flows in the direction of (3) along the partition walls 2f and 2g as shown in (c), and flows in the direction of (4) along the orifice 3 as shown in (d). As shown, it flows in the direction of (5) along the partition walls 2d and 2e and flows out from the pipe 5b. In this way, the cooling solvent 5 circulates uniformly in the hollow of the case 2, and in particular, a flow path of the cooling solvent 5 is formed along the vicinity of the orifice 3 having the most heat in the intermediate electrode 1. It cools evenly to protect it from the heat generated during plasma generation. In FIG. 1, reference numeral 6 denotes a cover that covers the vicinity of the orifice 3 of the intermediate electrode 1 so as not to be in direct contact with the plasma beam, and is made of a metal having a low sputtering rate such as tungsten, carbon, or the like.
[0019]
Here, the seal portions 2a, 2b, and 2c of the case 2 of the intermediate electrode 1 are substantially circular along the outer shape in order to form a hollow structure serving as a flow path for the cooling solvent 5 in the intermediate electrode 1. Since it is not necessary to have a structure for holding a magnet or coil in the hollow of the case as in the prior art, the position away from the orifice 3 can be achieved. That is, by separating the seal portions 2a, 2b, and 2c from the vicinity of the orifice 3 where the heat is concentrated as a plasma beam converging portion, the seal portion can be prevented from being broken.
[0020]
In addition to the first embodiment shown in FIG. 1, the seal portions 2a, 2b, and 2c may be, for example, the second embodiment to the fourth embodiment shown in FIGS. In particular, in the third embodiment shown in FIG. 6, the seal portion is only two portions 2 a and 2 b on the anode side of the intermediate electrode 1, the hollow structure is changed, and no seal portion is formed on the cathode side. Thus, the structure can prevent the influence of heat from the cathode. Similarly, in the fourth embodiment shown in FIG. 7, only two seal portions 2a and 2b are provided, and these seal portions 2a and 2b are formed on the side surface of the intermediate electrode 1, and the seal portions 2a and 2b are orifices. Since it is the position farthest from 3, it is more effective in terms of protecting the seal portion. Moreover, since these FIG. 6 and FIG. 7 have only two seal parts, it is effective also in manufacturing cost reduction.
[0021]
Note that the positions of the pipes 5a and 5b and the flow path of the cooling solvent 5 described in the above embodiment are merely examples, and any structure that can circulate the cooling solvent 5 in the intermediate electrode 1 may be used.
[0022]
The above embodiments all relate to the intermediate electrode structure of the pressure gradient type plasma generator, and the ion plating of various configurations using the pressure gradient type plasma generator having this intermediate electrode structure as in the conventional example. Needless to say, the present invention can be applied to a vacuum film forming apparatus such as an apparatus or a plasma CVD apparatus.
[0023]
【The invention's effect】
As described above, according to the present invention, the case side surface of the intermediate electrode of the pressure gradient type plasma generator is recessed along the outer periphery, and the annular shape for converging the plasma beam to pass through the through hole in the recess. By adopting a structure in which a magnet or coil is fitted, the magnet or coil that has been housed in the case and placed in the cooling solvent in the past is taken out of the case (outside the cooling solvent flow path) This is effective in preventing deterioration of the magnet and disconnection of the coil wiring. In addition, the cooling solvent circulates evenly in the hollow of the case, and the cooling solvent flow path is formed along the vicinity of the orifice that has the most heat in the intermediate electrode. The entire intermediate electrode is uniformly cooled. Furthermore, the seal part of the case of the intermediate electrode has a substantially circular shape along the outer shape in order to create a hollow structure that serves as a flow path for the cooling solvent in the intermediate electrode. Since it is not necessary to have a structure for holding the coil and the coil, it can be located away from the orifice, and the seal portion is separated from the vicinity of the orifice where the heat concentrates as the converging portion of the plasma beam. There is also an effect that the destruction of the part can be prevented.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first embodiment of an intermediate electrode structure of a pressure gradient plasma generating apparatus according to the present invention.
FIG. 2 is an explanatory view illustrating an example in which a magnet is used as an intermediate electrode structure of a pressure gradient type plasma generating apparatus according to the present invention.
FIG. 3 is a cross-sectional view showing an example in which a coil is used as an intermediate electrode structure of a pressure gradient plasma generating apparatus according to the present invention.
FIG. 4 is an explanatory diagram illustrating a flow of a cooling solvent in the intermediate electrode according to the present invention.
FIG. 5 is a cross-sectional view showing a second embodiment of the intermediate electrode of the pressure gradient plasma generating apparatus according to the present invention.
FIG. 6 is a cross-sectional view showing a third embodiment of an intermediate electrode of the pressure gradient type plasma generating apparatus according to the present invention.
FIG. 7 is a cross-sectional view showing a fourth embodiment of the intermediate electrode of the pressure gradient plasma generating apparatus according to the present invention.
FIG. 8 is a cross-sectional view showing an example of an ion plating apparatus in a conventional example.
FIG. 9 is an explanatory view showing an intermediate electrode structure of a pressure gradient type plasma generator in a conventional example, where (a) is a front view, (b) is a side view, and (c) is a longitudinal sectional view.
10A and 10B are explanatory diagrams for explaining the flow of a cooling solvent in an intermediate electrode in a conventional example, where FIG. 10A is a vertical sectional view and FIG. 10B is a horizontal sectional view.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Intermediate electrode 2 ... Case 2a, 2b, 2c ... Seal part 2d, 2e, 2f, 2g ... Partition wall 3 ... Through-hole (orifice)
4 ... Magnets 4a, 4b ... Split magnet 4c ... Coil 5 ... Cooling solvent 5a, 5b ... Cooling solvent piping 6 ... Cover

Claims (1)

A case having a through-hole in the center and a hollow inside, an annular magnet or coil fixed to the case for converging and passing the plasma beam to the through-hole, and circulating in the hollow of the case Then, in the intermediate electrode structure of the pressure gradient type plasma generator comprising a cooling solvent for cooling the whole,
The case has a structure in which the side surface is recessed along the outer periphery, and the magnet or coil is fitted in the recess .
Furthermore, the intermediate electrode structure of the pressure gradient type plasma generator characterized by forming the seal part for forming a hollow inside the said case along the outer periphery of the said case side surface .

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