Repeller assembly attached to the arc chamber of an ion implantation apparatus and arc chamber including the repeller assembly

Abstract

A repeller assembly attached to the arc chamber of an ion implantation apparatus. The repeller assembly includes a repeller, a cylindrical insertion member, first and second insulators, a contact member, and a locking member. The repeller has a knob-shaped body and is disposed in the arc chamber on the side opposite to the cathode assembly. The repeller shaft is arranged to extend outward through an opening in the wall of the arc chamber. The repeller shaft has a stepped portion that reduces the diameter of the repeller shaft. The cylindrical insertion member is attached concentrically with the repeller shaft. The first insulator has a collar shape and is attached to the cylindrical insertion member so that the inner shoulder of the first insulator is pressed against the outside of the wall of the arc chamber. The second insulator has a C shape and is attached to the first insulator using its outer flange.

Description

Technical Field

[0001] The present invention relates to a repeller assembly attached to an arc chamber of an ion implantation apparatus. More specifically, the present invention relates to a plurality of components of the repeller assembly and their configurations, the arrangements between those components, and the arrangements of those components within an opening in the wall of the arc chamber. Further, the present invention relates to an arc chamber that houses the repeller assembly.

Background Art

[0002] As is well known, in the manufacture of semiconductor components, ion implantation apparatuses are widely used to modify various regions of a semiconductor wafer. Thereby, positive or negative ions (dopants) are diffused or implanted onto the surface of the semiconductor wafer to generate regions having various characteristics (e.g., conductivity, etc.). These ion implantation apparatuses include an arc chamber, by which a plasma containing various ion species to be implanted onto the surface of the semiconductor wafer is generated.

[0003] In one of the general configurations known for an arc chamber, a repeller (anti-cathode) is disposed on the opposite side of a cathode assembly. During operation of the arc chamber, the cathode assembly is heated, for example, by a filament, the purpose of which is to emit electrons by thermionic emission during operation. The electrons are accelerated into the arc chamber by a relatively positive arc voltage on the wall of the arc chamber, and by an externally generated magnetic field, the electrons travel spirally into the arc chamber. Typically, the emitter electrode and the repeller electrode are negatively biased with respect to the wall of the arc chamber to confine the emitted electrons. Due to the combined effect of the emitter electrode and the repeller electrode, the electrons are concentrated toward the center of the arc chamber to maximize the interaction with the dopant gas introduced into the arc chamber through a conduit, and as a result, a plasma having desired characteristics is obtained.

[0004] During operation, the arc chamber contains a large number of molecular species at very high temperatures. In this harsh environment, each component, including the components of the repeller assembly, is exposed to conditions where their lifespan or their effectiveness can be overly restricted. As a result, either or both of the effectiveness of the ion implantation device being limited and the operating cost increasing have been brought about. For example, the plasma film tends to be deposited on components of the repeller assembly, such as components like the repeller shaft, the tubular shield, the insulator, etc. When a plasma coats (covers) an electrically insulated component such as a repeller, there is a risk of a short circuit occurring in the arc chamber. In such a case, the normal operation of the ion implantation device becomes impossible. Therefore, it is desirable to provide an extended and tortuous coating path to extend the coating process of the electrically insulated component (and correspondingly, the occurrence of a short circuit). Further, as another mode of failure, for example, gas loss in the arc chamber through the opening in the wall of the arc chamber where the repeller assembly is attached can be mentioned, which is due to the size of the gaps provided between the repeller assembly and the wall opening, as well as between the components of the repeller assembly. Further, due to mechanical or thermal changes, the repeller shaft or the repeller itself may move away from its cantilevered position and come into direct contact with the wall or the liner of the arc chamber.

[0005] In the prior art, some configurations of the repeller assembly are known. In one of the known configurations, the repeller has a wide portion (enlarged diameter portion) facing the center of the arc chamber and a narrower shaft portion (shaft portion) extending outside the arc chamber through the opening in the end wall of the arc chamber. To maintain the required electrical insulation, a ceramic insulator is disposed in the arc chamber between the end wall and the repeller.

[0006] U.S. Patent No. 8,796,649 discloses a modified configuration example. In FIG. 4 of that patent document, a repeller assembly is shown. At this time, the repeller has a knob-shaped main body (knob-shaped main body) with a diameter-expanded end at one end in the arc chamber and an integral stem passing through the opening of the end wall of the arc chamber. The configuration of the stem is characterized by comprising a pair of radially protruding collars. Further, a tubular shield (shielding portion) is concentrically attached within the opening of the end wall of the stem. In particular, at least one radially inward rib is provided between the collars of the stem. Further, an insulator ring surrounding the stem is screwed onto the tubular shield and abuts against the end wall. The insulator ring includes a disc-shaped end portion, which closes the plasma path from the arc chamber through the end wall by abutting against the outer collar on the stem. Therefore, on the one hand, a tortuous gap is defined between the stem and each of the opening of the end wall of the arc chamber, the tubular shield, and the insulator ring. A lock nut is screwed onto the end of the stem and abuts against the insulator ring to hold the anti-cathode (repeller) in a cantilevered manner within the arc chamber.

[0007] FIG. 13 of U.S. Patent No. 8,253,334 discloses a substantially similar repeller assembly. In this patent document, the repeller assembly is composed of a repeller, a liner, a tubular shield, an insulator, and a lock nut. A pair of spaced annular collars are provided on the stem of the repeller, and each annular collar is radially spaced from the tubular shield, introducing a further obstacle to the plasma flow from the arc chamber. Further, it is shown that the insulator ring has a disc-shaped end portion, which closes the plasma path from the arc chamber outward by abutting against the collar.

[0008] In the above patent documents, a tortuous gap / plasma path having a limited length is provided. Further, the configuration of the stem of the repeller creates a large gap between the stem and the opening of the end wall of the arc chamber and between the tubular shield and the insulator ring.

[0009] Therefore, in order to improve the lifespan and effectiveness of the repeller assembly and thereby improve the lifespan and effectiveness of the arc chamber, there remained room for improvement in the configuration or design of the repeller assembly.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0011] An object of the present invention is to provide a repeller assembly capable of achieving a longer operating time of an ion implantation apparatus. Increasing the operating time has, among other things, the effect of reducing the operating cost of the ion implantation apparatus. Furthermore, an object of the present invention is to provide a repeller assembly capable of achieving high operating efficiency by enabling reduction of gas leakage and reduction of coating formation.

Means for Solving the Problems

[0012] In view of the above object and other objects described herein, the invention provides a repeller assembly to be mounted inside an arc chamber of an ion implantation apparatus. The repeller assembly includes a repeller, a cylindrical insertion member, a first insulator, a second insulator, a contact member, and a locking member. The repeller has a knob-shaped body disposed inside the arc chamber on the side opposite to the cathode assembly of the arc chamber, and a repeller shaft integral with the knob-shaped body. The repeller shaft is arranged to extend outside the arc chamber through an opening in the wall of the arc chamber, and at least one stepped portion for narrowing the repeller shaft is provided on the repeller shaft. The cylindrical insertion member is mounted concentrically with the repeller shaft. The first insulator has an inner shoulder and a collar shape, and by being attached to the cylindrical insertion member, the inner shoulder of the first insulator is pressed against the outside of the wall of the arc chamber. The second insulator has a cap-nut shape and has an inner flange and an outer flange. The second insulator is attached to the first insulator via its outer flange. The contact member is electrically connected to the repeller shaft and The locking member is fixed to the repeller shaft so that at least one stepped portion of the repeller shaft is pressed against the inner flange of the second insulator.

[0013] In other words, by providing a repeller assembly attached to the arc chamber of an ion implantation apparatus, it becomes possible to solve the technical object of the present invention. At this time, the repeller assembly includes a repeller, a cylindrical insertion member, at least first and second insulators, a contact member, and a locking member. The repeller has a knob-shaped main body disposed inside the arc chamber on the side opposite to the cathode assembly of the arc chamber, and a repeller shaft integral with the main body disposed so as to extend outside the arc chamber through an opening in the wall of the arc chamber. The repeller shaft has at least one stepped portion that narrows (or reduces the diameter of) the repeller shaft, and the cylindrical insertion member is attached concentrically with the repeller shaft. The first insulator has a collar shape and is attached to the cylindrical insertion member so that the inner shoulder of the first insulator is pressed against the outside of the wall of the arc chamber. The second insulator has a cap-nut shape and is attached to the first insulator by its outer flange. The contact member is electrically connected to the repeller shaft, and the locking member is fixed on the repeller shaft so that the stepped portion of the repeller shaft is pressed against the inner flange of the second insulator, but these are as described in the first independent claim. The repeller assembly is assumed to be attached inside the arc chamber, and at this time, the arc chamber itself does not constitute a part of the present invention described in the first independent claim. This claim only explains the interactions between the respective parts (or components). Further, an arc chamber of an ion implantation apparatus is provided, and in this case, it is assumed that the repeller assembly described in the claims is attached and has the characteristics of the arc chamber described in the independent claim.

[0014] Further features and details of the present invention are described in each dependent claim and also in the following detailed description and the drawings. Needless to say, the features and details described with respect to the repeller assembly according to the present invention can also be applied to the arc chamber according to the present invention, and vice versa. Therefore, when explaining each aspect of the present invention, they can be referred to each other or can refer to each other.

[0015] The inventor has found that by using the repeller assembly described in the claims, a more extended and tortuous coating path can be provided compared to the prior art. In the prior art patent documents described above, there is a description of the tortuous gap between the repeller stem and each of the opening, the tubular shield, and the insulator ring. However, the length of this tortuous gap is limited especially based on the position of the last collar on the repeller stem. In contrast, when using the repeller assembly described in the claims of this patent, the gap between the repeller axis, the opening of the outer wall of the arc chamber, the cylindrical insertion member, and at least the first and second insulators is minimized, thus making it possible to reduce the gas lost from the arc chamber during the ion beam operation. As is well known, the repeller needs to be attached to the repeller assembly from the inside of the arc chamber. Therefore, it is clear that in the repeller assembly described in the prior art, the size of the opening in the end wall of the arc chamber had to be at least as large as the size of the protruding collar of the stem. For this reason, in such a configuration of the repeller stem, a large gap was created between the stem and the opening of the end wall of the arc chamber, the tubular shield, and the insulator ring.

[0016] Furthermore, in the repeller assembly described in the claims, the repeller axis can be easily introduced into the repeller assembly, and the repeller and the tubular sheet can be easily replaced. Regarding the prior art described above, the tubular shield was provided with at least one radially inward rib between each collar of the repeller stem. Therefore, it was clearly impossible to easily remove either or both of the repeller and the tubular shield from this combination because the repeller stem and the tubular shield were related to each other.

[0017] Therefore, it enables a longer lifespan of the arc chamber during the ion beam operation. Furthermore, the repeller assembly described in the claims makes it possible to reduce the frequency of maintenance stops in the arc chamber.

[0018] As one advantage of the present invention, the configuration of the repeller shaft of the repeller assembly described in the claims (having at least one stepped portion) is easier to manufacture (compared to a configuration having two colors), can be replaced more easily, and can be easily introduced through the opening in the wall of the arc chamber into the tubular shield and at least two insulators. As a further advantage of the present invention, the components of the repeller assembly described in the claims, namely, at least the repeller, the cylindrical insertion member, and at least the first and second insulators are self-aligning (or self-matching). This means is provided by at least one stage of the repeller shaft, as well as the cylindrical insertion member configuration and the two insulators and the insulator configuration. When the repeller assembly is mounted through the opening in the wall of the arc chamber, the repeller assembly itself can be automatically aligned. Preferably, when the first insulator is screwed onto the cylindrical insertion member, the second insulator is screwed onto the first insulator, and the locking member is screwed onto the end of the shaft portion, no additional device or measuring device is required to accurately position and attach the components of the repeller assembly in the arc chamber of the ion implantation device. The exact distance between the repeller assembly and the cathode assembly can also be automatically aligned.

[0019] The repeller of the repeller assembly described in the claims has a T-shaped cross-sectional shape. At this time, it has an enlarged tumor-shaped main body and a shaft portion integrated with the main body. This shaft portion has its diameter reduced in the diameter direction from the tumor-shaped main body to the end of the shaft portion by at least one step portion. When two or more step portions are provided on the repeller shaft, the diameter of the repeller shaft can be reduced at each step portion. That is, it is possible to gradually reduce the diameter of the repeller shaft by each additional step portion provided on the repeller shaft. The shaft portion is provided on the central axis of the tumor-shaped main body. Only one step portion for reducing the diameter of the repeller shaft toward the end of the repeller shaft can be provided on the repeller shaft, or two or more step portions for reducing the diameter of the repeller shaft toward the end of the repeller shaft can also be provided. For example, it is possible to provide two step portions or more step portions. The length of the repeller shaft depends on each component (or each constituent element) of the repeller assembly aligned along the shaft portion. What is important is that the repeller shaft passes through all the components of the repeller assembly, and the locking member abuts against the abutting member as the final component at the end of the repeller shaft. The repeller shaft is integral with the repeller body. This means that the repeller body and the repeller shaft can be integrally manufactured from the same material as one-piece components on the one hand. Such a manufacturing process is possible by powder metallurgy manufacturing (pressing powder into a desired shape and sintering), or also by melting metallurgy manufacturing (that is, manufacturing each component from a melt). On the other hand, the repeller body and the repeller shaft can be manufactured as two (or more) components, and then each component can be joined by a material joining process such as soldering or welding. In a preferred embodiment, the repeller is manufactured as a monolithic piece as an integral part. The repeller shaft has a major longitudinal axis direction. When the repeller has a strictly cylindrical shape and has several cylindrical sections or step portions, this major longitudinal axis direction corresponds to the cylindrical axis direction of the repeller.

[0020] Typically, the repeller is made of tungsten (W) or molybdenum (Mo). Preferably, the repeller is made of tungsten. Preferably, the material is as pure as possible, preferably 99.9% by weight. The configuration of the shaft portion of the repeller having at least one stepped portion facilitates the manufacture of the repeller described above as compared to the configuration of the repeller stem having two colors used in the prior art. Further, the configuration of the shaft portion having at least one stepped portion that narrows the diameter of the shaft portion provides the advantage of facilitating either or both of introducing and replacing the repeller from the inside of the arc chamber through the opening in the wall of the arc chamber with respect to the arrangement of the cylindrical insertion member and at least two insulators. By providing the repeller assembly described in the claims, due to the self-aligning configuration, the repeller can be accurately positioned and installed at a predetermined position in the arc chamber in a user-friendly manner without the need for additional devices or measuring devices. For this reason, for example, it is possible to avoid a situation where the working ability is usually reduced, such as tilting the repeller.

[0021] The cylindrical insertion member has the shape of a flanged bushing. When the impeller assembly is attached to the arc chamber, the cylindrical insertion member is arranged concentrically with the impeller shaft within the opening of the wall of the arc chamber. Therefore, the flanged side portion of the cylindrical insertion member is oriented towards the inside of the arc chamber and has a diameter larger than that of the opening that abuts against the wall of the arc chamber. Preferably, the flanged side portion of the cylindrical insertion member and the opening of the wall of the arc chamber are chamfered so that the flange abuts against the opening of the wall of the arc chamber. The bushing of the cylindrical insertion member is connected to the first insulator on the side opposite to the flange side. Therefore, the inner shoulder of the first insulator is pressed against the outside of the wall of the arc chamber. The cylindrical insertion member has a larger inner diameter at the location of the flange than at the location of the bushing. When an impeller shaft having two stepped portions is used for the impeller assembly, the first stepped portion of the impeller shaft having two stepped portions may be positioned at the flanged side portion of the cylindrical insertion member. The cylindrical insertion member is preferably made of tungsten or molybdenum. In different embodiments, the cylindrical insertion member is made of an electrically insulating material, for example, a high-temperature ceramic material such as Al2O3, so that the cylindrical insertion member can function as an insulator. Means are provided on the cylindrical insertion member for holding the first insulator and guiding the impeller shaft towards the second insulator.

[0022] The first insulator has a collar shape, which includes, in the radial direction (from the inside to the outside, perpendicular to the repeller axis), an inner shoulder (or inner shoulder) and an outer shoulder (or outer shoulder). The inner shoulder is rotated towards the repeller axis, and the outer shoulder is arranged on the opposite side of the inner shoulder. When the repeller assembly described in the claims is installed in the arc chamber, the first insulator is attached to the cylindrical insertion member such that the inner shoulder is pressed against the outside of the wall of the arc chamber. The first repeller can be provided with a circumferential recess (or circumferential recess), which faces the inner shoulder and the outer shoulder of the first repeller (in the main longitudinal axis direction of the assembly). This recess extends the coating path / plasma path of the repeller assembly. In a preferred embodiment, the first insulator and the cylindrical insertion member are attached to each other by screwing (for example, screwing in), so that both parts are closely connected and the inner shoulder of the first insulator is pressed against the outside of the wall of the arc chamber.

[0023] The second insulator has a cap-nut-like structure, which includes, in the radial direction (from the inside to the outside, perpendicular to the repeller axis), an inner flange and an outer flange. The outer flange of the second insulator is attached to the outer shoulder of the first insulator, and the inner flange of the second insulator is pressed against one step of the repeller axis. Therefore, the second insulator and one step of the repeller axis (or the step of the repeller axis having one step with the second insulator) close the plasma path starting from the arc chamber. When a repeller axis having two steps is used, preferably, the last step towards the end of the repeller axis closes the plasma path starting from the arc chamber. In a preferred embodiment, the first insulator and the second insulator are attached to each other by screwing (for example, screwing in).

[0024] The first and second insulators are arranged successively in the repeller assembly along the repeller axis in the main longitudinal axis direction (x direction / axial direction). The radial directions (y and z directions) are perpendicular to the main longitudinal axis direction.

[0025] The first and second insulators are made of a high-temperature ceramic material, preferably made of AI2O3, to electrically insulate the repeller from the arc chamber.

[0026] The contact member is electrically connected to the repeller shaft and is connected to the cathode support with a bias. Preferably, the contact member is a cathode strap made of molybdenum (Mo), tungsten (W), or silver (Ag). The contact member is disposed between the second insulator and the locking member.

[0027] The locking member is fixed on the end of the repeller shaft so that the stepped portion of the repeller shaft having one stepped portion is pressed against the inner flange of the second insulator. When a configuration of the repeller shaft having two stepped portions is used, preferably, the last stepped portion of the end of the repeller shaft is pressed against the inner flange of the second insulator. Thus, the repeller is held in a cantilever manner within the arc chamber. The locking member may be made of molybdenum, tungsten, or stainless steel. In a preferred embodiment, the locking member is a lock nut.

[0028] In a preferred embodiment, the repeller assembly further includes a cup-shaped shielding portion. The cup-shaped shielding portion is inserted between the second insulator and the contact member to cover at least the first and second insulators. Preferably, a circumferential recess is provided around the opening on the outside of the wall of the arc chamber so that the cup-shaped shielding portion reaches within this recess. The cup-shaped shielding portion can be made of different materials such as graphite or a metal material. Preferably, the cup-shaped shielding portion is made of a metal material such as aluminum, stainless steel, molybdenum, or tungsten. In another embodiment, the cup-shaped shielding portion is made of an electrically insulating material, preferably made of a ceramic such as AI2O3, so that the cup-shaped shielding portion can function as an insulator. When the cup-shaped shielding portion is made of a metal material, it can be easily cleaned from the deposited plasma and can also be reused within the repeller assembly, thus achieving cost savings.

[0029] In a preferred embodiment, the repeller assembly is composed of a repeller, a cylindrical insertion member, first and second insulators, a contact member, and a locking member.

[0030] In a more preferred embodiment, the repeller assembly is composed of a repeller, a cylindrical insertion member, first and second insulators, a cup-shaped shielding portion, a contact member, and a locking member.

[0031] In a preferred embodiment of the present invention, at least some parts of the repeller assembly, particularly the repeller, the cylindrical insertion member, and at least the first and second insulators, are geometrically configured such that these parts self-align when assembled along the main longitudinal axis direction (x-direction / axial direction) of the repeller axis. When the repeller is, for example, a precisely cylindrical shape with several cylindrical sections, the main longitudinal axis direction corresponds to the cylindrical axis direction. Therefore, these components are arranged axially at the correct distance from each other and are correctly and firmly positioned relative to each other in the radial direction (perpendicular to the axial direction). As described above, these components have corresponding geometrically configured shapes so that the feature of self-alignment is realized (this will be described in more detail with reference to the drawings). In a preferred embodiment, this is achieved, inter alia, by the inclined wall of the opening and the corresponding inclined wall of the flange of the cylindrical insertion member. Therefore, when these components are installed in the arc chamber of the ion implantation device, the correct arrangement between these components is ensured. Furthermore, due to the self-aligning feature, no additional devices or measuring devices are required to accurately arrange each component of the repeller assembly.

[0032] The present invention also relates to an arc chamber of an ion implantation device including the repeller assembly described in the claims. The repeller assembly is arranged within an opening in the wall of the arc chamber, on the side opposite to the cathode assembly of the arc chamber. For example, the wall of the arc chamber provided with the opening may be the rear wall of the arc chamber.

[0033] By using the repeller assembly described in the claims, an inner gap (or inner clearance) is defined between the arc chamber and the repeller assembly. At this time, this inner gap extends along the body of the repeller, then along the shaft portion of the repeller, and further extends between the first insulator and the second insulator and terminates there. Since the inner gap is formed along the body of the repeller, it is restricted on the opposite side by adjacent portions of the body of the repeller, such as the wall of the arc chamber, the end liner (or endliner), and / or the tubular insertion member. Next, the inner gap extends along the shaft portion of the repeller, where the inner gap is restricted on the opposite side by adjacent portions, such as the tubular insertion member and, for example, the first insulator. In a further process, the inner gap is restricted by at least the first and second insulators and the arrangement of the circumferential recess on one side of the first insulator.

[0034] In the prior art, a repeller stem having a pair of radially protruding collars may have been used. Compared with the gap of this known configuration, the above-mentioned inner gap is very small. In the prior art, due to the need to introduce the repeller from the inside of the arc chamber into the opening of the end wall of the arc chamber, the width of the gap between the repeller stem and each of the opening, the tubular shield, and the insulator ring depends on the size of the radially protruding collar of the repeller stem. The size of the inner gap according to the present invention is 2 mm or less, preferably in the range of 0.4 mm to 1.5 mm, and more preferably in the range of 0.5 mm to 1.0 mm. Therefore, by using the repeller assembly described in the claims, the size of the gap can be minimized, and as a result, the gas lost in the arc chamber during the ion beam operation can be reduced.

[0035] Furthermore, the inner clearance forms an extended and tortuous path based on the specific configuration of different components of the repeller assembly. This path extends from the inside of the arc chamber, through the wall opening, to the outside of the arc chamber when viewed from the inside of the arc chamber, and has at least five turns (curves) and at least one side branch (or bifurcation). The side branch preferably extends between at least two insulators, and more preferably extends within the first insulator. Also, the width of the side branch is preferably less than 2 mm, preferably within the range of 0.4 mm to 1.5 mm, and more preferably within the range of 0.5 mm to 1.0 mm. Therefore, compared with the paths disclosed in the prior art, the above-described plasma path is extended because at least two insulators are used. When a configuration of a repeller shaft having two stepped portions is used, the inner clearance forms an extended and tortuous path having at least seven curves and at least one side branch. During the ion beam operation of the arc chamber, such an extended and tortuous path can delay the accumulation of a conductive plasma layer on the surfaces of the components of the repeller assembly. As a result, it becomes possible to extend the life of the repeller assembly during the ion beam operation.

[0036] Furthermore, the arc chamber described in the claims including the repeller assembly defines an outer clearance that extends between the outside of the arc chamber and the first insulator, then extends into the first insulator, and terminates there. In this case, the outer clearance forms a path having one curve. The width of the outer clearance is 2 mm or less, preferably within the range of 0.4 mm to 1.5 mm, and more preferably within the range of 0.5 mm to 1.0 mm. It should be noted that none of the above-mentioned patent documents disclose or suggest the outer clearance.

[0037] In a preferred embodiment of the present invention, the outer side of the arc chamber wall shows a circumferential recess, and a cup-shaped shielding portion is inserted between the second insulator and the contact member to cover at least the first and second insulators and reach at least partially into the recess on the outer side of the arc chamber. In this case, since the outer gap further extends between the outer side of the arc chamber and the cup-shaped shielding portion, the outer gap forms an extended and meandering path having at least three curvatures. When viewed in the direction from the outer side of the cup-shaped shielding portion along the outer side of the arc chamber, it then extends between the outer side of the arc chamber and the first insulator, then extends into the first insulator and terminates there. In this embodiment, it is clear that at least two curvatures are obtained by the outer side of the arc chamber wall having a circumferential recess and the cup-shaped shielding portion reaching at least partially into this recess. By providing the cup-shaped shielding portion, the outer gap further has side branches, which extend between the first insulator and the cup-shaped shielding portion and then between the second insulator and the cup-shaped shielding portion and terminate there. Therefore, in this preferred embodiment, the cup-shaped shielding portion is inserted between the second insulator and the contact member, covers at least the first and second insulators, reaches at least partially into the recess provided on the outer side of the arc chamber wall, and the outer gap forms a meandering path having at least three curvatures and at least one side branch.

[0038] As described above, when the repeller and the cylindrical insertion member are arranged inside the arc chamber, and at least the first and second insulators are arranged outside the arc chamber, and these components are assembled together through the opening of the wall of the arc chamber, each component of the repeller assembly self-aligns along the main longitudinal axis direction of the repeller shaft. As described above, the main longitudinal axis direction of the repeller shaft corresponds to the cylindrical axis direction of the repeller. Therefore, these components are arranged at the correct distance from each other in the axial direction and are correctly and firmly positioned with respect to each other in the radial direction (perpendicular to the axial direction). As described above, the distance between the repeller assembly and the cathode assembly is also automatically and accurately aligned (or positioned). Compared with the case where the assemblies are insufficiently / misaligned, the above-described repeller assembly is advantageous because it exhibits better performance and a longer service life. Incorrect alignment of the repeller assembly can result in either or both of affecting the short circuit and the arc chamber not operating correctly.

[0039] Further features that are considered to be characteristics of the present invention are set forth in the appended claims.

[0040] The present invention is described and illustrated herein as being embodied as a repeller assembly mounted inside an arc chamber of an ion implantation apparatus and an arc chamber including the repeller assembly. However, without departing from the technical idea of the present invention, various modifications and structural changes can be made to the present invention within the scope of equivalents of the claims, and it is not intended to limit the present invention to the details shown here.

[0041] The structure and operation method of the present invention can be best understood together with the appended drawings by reading the following detailed description of specific embodiments, along with further objects and advantages.

Brief Description of the Drawings

[0042]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4A

Figure 4B

DETAILED DESCRIPTION OF THE INVENTION

[0043] Hereinafter, referring to the drawings in detail, first referring to FIG. 1, an external view of an arc chamber (or arc chamber) 1 of an ion implantation apparatus is illustrated. The arc chamber 1 has an elongated box-shaped structure, which includes a bottom, four side walls, and a top wall, and a liner (not visible in the figure) is provided on its lower side. In FIG. 1, one outer wall, that is, the rear wall 3, is included in the arc chamber at one end of the arc chamber 1, and an opening 13 for attaching a repeller assembly (or repeller assembly) is provided therein. FIG. 1 illustrates the arc chamber 1 including a repeller assembly according to a preferred embodiment of the present invention. A cathode assembly (or cathode assembly) is provided on the opposite side of the repeller assembly (on the front wall of the arc chamber). In the embodiment illustrated in FIG. 1, the repeller of the repeller assembly described in the claims, the cylindrical insertion member (or tubular insert) Also, at least the first and second insulators are covered by a cup-shaped shield 8 (thus, they are not visible in FIG. 1). The cup-shaped shield 8 is fixed to the contact member 10 (e.g., cathode strap) by a locking member 9 (e.g., lock nut). As is apparent from FIG. 1, the cup-shaped shield 8 and the contact member 10 are provided with holes (e.g., bore holes) so that the repeller shaft (or repeller shaft) can pass through these portions. Further, in the same figure, since the locking member 9 is screwed to the end of the repeller shaft, the end of the repeller shaft 2b is visible.

[0044] Figure 2 illustrates a partial preferred embodiment of the repeller assembly recited in the claims. Figure 2 shows a repeller 2 having a tumorous body (or knob-like body) 2a and a repeller shaft 2b, a cylindrical insertion member 5, a first insulator 6, a second insulator 7, a cup-shaped shielding portion 8, a contact member 10 (e.g., a cathode strap), and a locking member 9 (e.g., a lock nut). When the repeller assembly is assembled together, the repeller shaft 2b passes through all the parts, namely, the cylindrical insertion member, the first and second insulators, the cup-shaped shielding portion, and the contact member (both having holes in this region. See also Figure 1), and is fixed to the end using the locking member 9, which in this example is a lock nut. As is apparent from Figure 2, in this embodiment, the cylindrical insertion member 5 and the first insulator 6 are screwed together and attached. The same applies to the first insulator 6 and the second insulator 7. A cup-shaped shielding portion 8 is disposed on the combined first and second insulators, and the cup-shaped shielding portion 8 completely covers (towards the outside) the first and second insulators. Further, due to the specific configuration or design of the repeller shaft 2b, the cylindrical insertion member 5, the first (i.e., collar-shaped) insulator 6, and the second (i.e., cap-nut-shaped) insulator 7, it is possible to easily introduce the repeller 2 into the assembly, where the repeller shaft 2b is inserted into a concentric hole (i.e., the inner flange of the second insulator) provided in the center of the second insulator 7 before being fixed. Along the major longitudinal axis direction in which the repeller shaft extends, i.e., along the central axis of the repeller shaft, all the parts of the repeller assembly are assembled together. Figure 2 shows that the repeller, the cylindrical insertion member, and the first and second insulators are self-aligning along the major longitudinal axis direction of the repeller shaft. Therefore, when installed within the opening in the wall of the arc chamber of the ion implantation device, the correct arrangement among these parts of the repeller assembly is ensured. When a threaded connection (or screw connection) is used between the cylindrical insertion member and the first insulator, and between the first insulator and the second insulator, the first and second insulators may first be assembled together and then attached as an integral part onto the cylindrical insertion member. Further, when a threaded connection is used between these parts, since the repeller assembly is self-aligning, no additional tools are required for the precise positioning of the repeller assembly.Furthermore, as is apparent from FIG. 2, since all parts of the repeller assembly are reversibly arranged, it is possible to replace a single part of the repeller assembly, for example, the repeller.

[0045] Referring to FIG. 3A, a cross-sectional view of an embodiment of the repeller assembly recited in the claims is illustrated. In FIG. 3A, an arc chamber 1 including the repeller assembly recited in the claims and a cup-shaped shielding portion 8 is illustrated. The repeller assembly is mounted within the arc chamber 1 through an opening 13 in a wall at one end of the arc chamber 1, i.e., the rear wall 3 of the arc chamber. The repeller assembly is disposed on the opposite side of the cathode assembly at the other end (i.e., the front wall) of the arc chamber (not shown). The repeller assembly is composed of a repeller 2, a cylindrical insertion member 5, a first insulator 6, a second insulator 7, a contact member 10, and a locking member 9. Further, a cup-shaped shielding portion 8 is illustrated in FIG. 3A, which is disposed between the second insulator 7 and the contact member 10 and covers the first and second insulators. In FIG. 3A, it is rotationally symmetric with respect to the repeller assembly, and reference numerals for explaining the components of the repeller assembly are given only once. This does not apply to the components of the arc chamber (e.g., the top wall, the liner, or the end liner). As described above, the rear wall 3 is provided with an opening 13. The repeller 2 and the cylindrical insertion member 5 need to be inserted into the repeller assembly from the inside 1a of the arc chamber. Outside the arc chamber, the first and second insulators, the contact member 10, the locking member 9, and the cup-shaped shielding portion 8 are disposed. A circumferential recess (or circular recess) 14 around the opening 13 of the rear wall 3 is shown on the outside 3b of the rear wall 3. Also, in FIG. 3A, the top wall 12 of the arc chamber, the inside of the arc chamber, the liner 11 below the top wall, and the end liner (or end liner) 4 are shown. The repeller 2 has a bulged main body 2a with an enlarged diameter inside the arc chamber and an integral shaft portion (repeller shaft) 2b, and the latter extends outward from the arc chamber through the opening 13 in the rear wall 3. The repeller shaft 2b is integrally provided with respect to the center of the bulged main body having a predetermined initial diameter. The repeller shaft 2b has one step portion (or step), which reduces or narrows the initial diameter of the shaft portion at the starting end of the shaft portion (starting from the bulged main body) toward the ending end of the shaft portion, and the diameter of the repeller shaft is narrowed behind the step portion.The end liner 4 is attached using a spacer ring 4a located between the inner side 3a of the rear wall 3 of the arc chamber and the nodular structure 2a, thereby preventing flakes (or peeling) during operation that could cause a short circuit. Further, this configuration extends the inner clearance, thereby further extending the coating path. Concentrically around the repeller shaft, a cylindrical insertion member 5 is attached within the opening of the rear wall. The cylindrical insertion member 5 is a flanged bushing and has, at one end, a flange directed towards the inner side 1A of the arc chamber 1 and, at the other end, a bushing or bush having a uniform diameter. The opening of the rear wall 3 is axially inclined from the inner side 3a to the outer side 3b of the rear wall 3, so the flange of the cylindrical insertion member is axially inclined and has a larger diameter than the bushing. For this reason, the cylindrical insertion member is in contact with the rear wall 3 of the arc chamber 1. The bushing of the cylindrical insertion body comprises means for holding a first insulator 6. The first insulator 6 has a collar shape including an inner shoulder 6b and an outer shoulder 6a in the radial direction. The first insulator is attached to the cylindrical insertion member 5 such that the inner shoulder 6b of the first insulator is pressed against the rear wall 3 of the arc chamber. For this reason, the first insulator is in contact with the rear wall of the arc chamber. Further, the first insulator has, at one end of the first insulator, on the side opposite to the outer and inner shoulders, a circumferential recess 15. A second insulator 7 is attached to the first insulator and has a cap-nut-like structure. As illustrated in Fig. 3A, the outer flange 7a of the second insulator is attached to the first insulator. Further, the inner flange 7b of the second insulator is in contact with a stepped portion of the repeller shaft. As described above, the cup-shaped shielding portion 8 covers the first and second insulators and further reaches into a recess 14 provided on the outer side of the rear wall 3b. The contact member 10 is electrically connected to the end of the repeller shaft and is arranged to be attached to the cup-shaped shielding portion and the repeller assembly using a fixing member 9. Accordingly, the inner flange 7b of the second insulator is pressed against the stepped portion of the repeller shaft 2b, and the flange 7a of the second insulator is pressed against the outer shoulder 6a of the first insulator.

[0046] It is necessary to attach the impeller so that it passes through the opening 13 of the rear wall 3 from the inside 1a of the arc chamber 1 to the other parts of the assembly. Therefore, although it goes without saying, the impeller shaft is designed to enable the easy introduction and replacement of the impeller. FIG. 3A illustrates an embodiment in which the bushing of the cylindrical insertion member 5 is screwed (or threaded) onto the first insulator 6. Further, the first insulator 6 is screwed onto the second insulator 7, and the locking member 9 is screwed onto the end of the impeller shaft 2b. In this preferred embodiment, the components of the impeller assembly self-align when these components are assembled together along the main longitudinal axis direction of the impeller shaft 2b. In FIG. 3A, the main longitudinal axis direction is illustrated as the x-axis (axial direction). The geometric shapes of the components of the impeller assembly are defined so that the components can be accurately self-aligned at fixed positions in the x, y, and z directions. Therefore, the impeller assembly described in the claims can be easily installed in the arc chamber, and at that time, no additional devices or measuring devices that are usually required to correctly position the components of the impeller assembly within the opening of the arc chamber wall are needed.

[0047] FIG. 3B shows a repeller assembly mounted in the arc chamber, similar to FIG. 3A, with particular emphasis on the inner gap (or inner gap) and outer gap (or outer gap) defined when the repeller assembly is inserted into the arc chamber. The inner gap extends along the body of the repeller (restricted on the opposite side by the end liner and the cylindrical insertion member), then extends along the axis of the repeller (restricted on the opposite side by the cylindrical insertion member and the first insulator), and further extends between the first and second insulators and terminates there. In this embodiment, the first insulator has a circumferential recess, which acts as a branch (or branch) with respect to the inner gap. The black lines illustrate the plasma / gas flow from the inner / inner side to the outer / outer side of the arc chamber. As shown, the gas (or gas) flows along the repeller, through the opening in the rear wall of the arc chamber, and further along the cylindrical insertion member, the first insulator, and the second insulator. The installation of the cylindrical insertion member and the specific configuration of the two insulators make it possible to provide an extended and tortuous inner gap for the plasma flow. This gap has five bends (or turns) and one branch (as seen from the inside of the arc chamber). Therefore, the time until the entire gap is covered with plasma is extended. For this reason, the time until the entire gap is covered with plasma is extended. As a result, the long life of the arc chamber is further extended. FIG. 3B further illustrates the outer gap. In the absence of the cup-shaped shielding portion, the outer gap extends between the outside of the rear wall 3b of the arc chamber and the first insulator and terminates there. In this regard, FIG. 3B illustrates a preferred embodiment of the repeller assembly having a cup-shaped shielding portion. For this reason, the outer gap further extends outside the cup-shaped shielding portion 8a, extends between the cup-shaped shielding portion and the rear wall of the arc chamber, and further extends between the second insulator and the cup-shaped shielding portion and terminates there. The outside of the rear wall of the arc chamber provides a circumferential recess, and the cup-shaped shielding portion extends at least partially into this recess. Therefore, in this configuration, the outer gap provides two additional bends compared to an embodiment where the rear wall is not provided with a recess. FIG. 3B shows an extended and tortuous outer gap for the plasma flow.This gap has four curved portions and one side branch. In the figure, it is exemplified that the inner gap and the outer gap each have a width of 2 mm or less over their entire lengths.

[0048] FIG. 4A illustrates a cross-sectional view according to another embodiment of the repeller assembly described in the claims. The main part of this figure corresponds to the repeller assembly illustrated in FIG. 3A. However, two stepped portions are provided on the repeller shaft of the repeller. Therefore, here, the description of FIG. 3A can be mainly referred to, and only the differences in the arrangement of the repeller assembly when compared with the repeller assembly shown in FIG. 3A are emphasized. In this repeller assembly, the two stepped portions of the repeller shaft 2b narrow the initial diameter of the shaft from the start end of the shaft (starting from the tuberous protrusion) to the end of the shaft, and at each stepped portion, the diameter of the repeller shaft is reduced. In this embodiment, the second stepped portion provided at the end of the repeller shaft is pressed against the inner flange portion 7b of the second insulator, and the first stepped portion of the repeller shaft (arranged close to the tuberous body) is arranged within the flange (or flange) of the cylindrical insertion member 5 when the entire arrangement is fixed on the repeller shaft.

[0049] FIG. 4B shows a repeller assembly mounted in the arc chamber, similar to FIG. 4A, but in particular, the inner gap and the outer gap defined when the repeller assembly is inserted into the arc chamber are emphasized. In FIG. 3B, the paths of the inner gap and the outer gap are explained, and the description of FIG. 3B can also be applied in the same way to FIG. 4B. At this time, the black line indicates the flow of plasma / gas from the inner / inner side to the outer / outer side of the arc chamber. By providing the cylindrical insertion member and the two insulators and providing two stepped portions on the shaft, an extended and winding inner gap for the plasma flow is provided, and at this time, this gap has seven curved portions and one side branch (seen from the inside of the arc chamber). Also, in the figure, it is exemplified that the inner gap and the outer gap each have a width of 2 mm or less over their entire lengths.

[0050] As described above, the invention described in the claims provides a repeller assembly, which can improve the life performance of the ion implantation apparatus during ion beam operation when it is installed in the arc chamber of the ion implantation apparatus. Therefore, the invention described in the claims can reduce the frequency of maintenance stops in the arc chamber.

[0051] Due to the self-aligning configuration of these components, it becomes possible to accurately install the repeller assembly without using additional devices or measuring devices.

[0052] Furthermore, each individual component of the repeller assembly enables either or both of easier manufacturing (such as for the repeller) and easier replacement.

[0053] The reference numbers used in the above description of the present invention and a summary list of the corresponding structures are shown below.

Description of Reference Signs

[0054] 1 Arc chamber (or arc chamber) 1a Inside of the arc chamber 2 Repeller 2a Knob-like protrusion of the repeller 2b Repeller integral shaft portion 3 Rear wall of the arc chamber 3a Inside of the rear wall 3b Outside of the rear wall 4 End liner (or end liner) 4a Spacer ring 5 Cylindrical insertion member (or tubular insert) 6 First insulator 6a Inner shoulder of the first insulator (or inner shoulder) 6b Outer shoulder of the first insulator (or outer shoulder) 7 Second insulator 7a Outer flange of the second insulator (or outer flange) 7b Inner flange of the second insulator (or inner flange) 8 Cup-shaped shielding portion (or cup-shaped shield) Outside of the 8a cup-shaped shielding part 9 Locking member, preferably a lock nut 10 Contact member (or contact member), preferably a strap 11 Liner 12 Top wall of the arc chamber 13 Opening in the rear wall of the arc chamber 14 Concave portion outside the rear wall 15 Concave portion of the first insulator

Claims

1. A repeller assembly mounted in an arc chamber of an ion implantation apparatus, comprising a repeller, a cylindrical insertion member, a first insulator, a second insulator, a contact member, and a locking member, wherein the repeller has a knob-shaped body disposed inside the arc chamber on the side opposite to the cathode assembly of the arc chamber, and a repeller shaft integral with the knob-shaped body, the repeller shaft is disposed to extend outside the arc chamber through an opening in the wall of the arc chamber, and at least one stepped portion for narrowing the repeller shaft is provided on the repeller shaft, the cylindrical insertion member is mounted concentrically with the repeller shaft, the first insulator has an inner shoulder and a collar shape, and by being attached to the cylindrical insertion member, the inner shoulder of the first insulator is pressed against the outside of the wall of the arc chamber, the second insulator has a cap-nut shape and has an inner flange and an outer flange, and the second insulator is attached to the first insulator via the outer flange, the contact member is electrically connected to the repeller shaft, and the locking member is fixed to the repeller shaft so that at least one stepped portion of the repeller shaft is pressed against the inner flange of the second insulator, a repeller assembly.

2. The repeller assembly according to claim 1, wherein the contact member is disposed between the second insulator and the locking member.

3. Further comprising a cup-shaped shielding portion, the cup-shaped shielding portion is inserted between the second insulator and the contact member, and covers at least the first and second insulators, the repeller assembly according to claim 1 or 2.

4. The repeller assembly according to any one of claims 1 to 3, wherein the contact member is a cathode strap.

5. The repeller assembly according to any one of claims 1 to 4, wherein the locking member is a lock nut.

6. When assembling the repeller, the cylindrical insertion member, and the first and second insulators of the repeller assembly together, the components are geometrically configured so that the components are self-aligning along the major longitudinal axis direction of the repeller shaft, the repeller assembly according to any one of claims 1 to 5.

7. The repeller assembly according to any one of claims 1 to 6, wherein the first insulator and the cylindrical insertion member are attached to each other by a screw connection.

8. The first insulator and the second insulator are attached to each other by a screw connection, the repeller assembly according to any one of claims 1 to 7.

9. On the repeller shaft, only one of the at least one stepped portion is strictly provided, and the stepped portion narrows the repeller shaft toward the end of the repeller shaft, the repeller assembly according to any one of claims 1 to 8.

10. The at least one stepped portion that narrows the repeller shaft is one of at least two stepped portions that narrow the repeller shaft toward the end of the repeller shaft, the repeller assembly according to any one of claims 1 to 8.

11. The cylindrical insertion member is made of an electrically insulating material, the repeller assembly according to any one of claims 1 to 10.

12. The cup-shaped shielding portion is made of an electrically insulating material, the repeller assembly according to claim 3.

13. An arc chamber of an ion implantation apparatus, A cathode assembly, A wall provided with an opening, The repeller assembly according to any one of claims 1 to 12, and includes, The repeller assembly is disposed in the opening of the wall of the arc chamber on the side opposite to the cathode assembly of the arc chamber, defining an inner gap, the inner gap extending along the tumorous body of the repeller, then extending along the shaft portion of the repeller, then extending between the first insulator and the second insulator, and terminating there, and the width of the inner gap is 2 mm or less, the arc chamber.

14. The inner gap forms a winding path including at least five bends and at least one side branch, the arc chamber according to claim 13.

15. When the repeller and the cylindrical insertion member are disposed inside the arc chamber, and the first and second insulators are disposed outside the arc chamber, and the components are assembled together through the opening of the wall portion of the arc chamber, the repeller, the cylindrical insertion member, and the first and second insulators of the repeller assembly are geometrically configured so that the components are self-aligned along the main longitudinal axis direction of the repeller shaft, the arc chamber according to claim 13 or 14.

16. An outer gap is defined outside the arc chamber, the outer gap extending between the outside of the arc chamber and the first insulator, then extending into the first insulator and terminating therein, and the width of the outer gap being 2 mm or less. The arc chamber according to any one of claims 13 to 15.

17. The arc chamber according to claim 16, further comprising a cup-shaped shielding portion, the outer gap further extending between the outside of the arc chamber and the cup-shaped shielding portion, the outer gap forming a meandering path including at least three curvatures.

18. The arc chamber according to claim 17, wherein the outer gap further includes side branches, the side branches extending between the first insulator and the cup-shaped shielding portion, then extending between the second insulator and the cup-shaped shielding portion and terminating therein.

Images