TWI766850B - Ion source liner having a lip for ion implantation systems - Google Patents

Abstract

An ion source has an arc chamber having a body defining and interior region. A liner defined an exposure surface of the interior region that is exposed to a plasma generated within the arc chamber. An electrode has a shaft with a first diameter that passes through the body and the liner. The electrode is electrically isolated from the body where the liner is a plate having a first surface with an optional recess having a second surface. A hole is defined through the recess for the shaft to pass through. The hole has a second diameter that is larger than the first diameter, and an annular gap exists between the plate and the shaft. The plate has a lip extending from the second surface toward the first surface that surrounds the hole within the recess and generally prevents particulate contaminants from entering the annular gap.

Description

Ion source liners with lips for ion implantation systems

The present invention generally relates to ion implantation systems, and more particularly, to a liner for an ion source arc chamber.

In the manufacture of semiconductor devices, ion implantation is used to incorporate impurities into the semiconductor. Typically, it uses an ion implantation system that uses ions from an ion beam to dope a workpiece, such as a semiconductor wafer, to produce n-type or p-type material doping, or in integrated circuit fabrication. During this period, a passivation layer is formed. Such beam processing is often used to selectively implant impurities of a specific dopant material into wafers at a specific energy level at controlled concentrations to produce a semiconductor material during the production of an integrated circuit . When used to dope semiconductor wafers, ion implantation systems implant a selected ion species into the workpiece to produce the desired extraneous material. Implanted ions generated from native materials such as antimony, arsenic, or phosphorous, for example, result in an "n-type" exo-material wafer, while a "p-type" exo-material wafer is typically derived from materials such as boron , gallium, or indium and other source materials generated ions.

A typical ion implanter includes an ion source, an ion extraction device, a mass analysis device, a beam delivery device, and a wafer processing device. The ion source produces ions of the desired atomic or molecular dopant species. this plasma The daughter system is extracted from the source by an extraction system, typically a set of electrodes that excite and direct the flow of ions from the source to form an ion beam. The desired ions are separated from the ion beam in a mass analysis device, typically a magnetic dipole, that performs mass dispersion or separation of the extracted ion beam. A beam delivery device, typically a vacuum system comprising a series of focusing devices, delivers the ion beam to the wafer processing device while maintaining the desired properties of the ion beam. Finally, semiconductor wafers are fed into and out of the wafer handling apparatus through a wafer handling system, which may include one or more robotic arms for placing a wafer to be processed in the ion beam front and remove the processed wafer from the ion implanter.

Batch-type ion implanters are well known and typically include a rotating disk support to move multiple silicon wafers through the ion beam. As the support rotates the wafer through the ion beam, the ion beam strikes the wafer surface. Tandem ion implanters are also known devices that process one wafer at a time. Wafers are supported in a cassette, one at a time is pulled out and placed into a wafer support. The wafer is then adjusted to an implant orientation such that the ion beam strikes a single wafer. These in-line implanters use beam shaping electronics to deflect the beam from its original trajectory, and are typically used in conjunction with co-ordinated wafer support movement to selectively dope or treat the entire wafer surface. As wafers are processed through an ion implantation system, they are transferred between dedicated processing chambers and wafer input/output stations. It routinely uses robots to move wafers in and out of the chamber.

The present disclosure therefore proposes a system and apparatus for increasing the lifetime of an ion source. Accordingly, a simplified summary of the disclosure is presented below to provide a basic understanding of some of the features of the invention. This abstract is not an extensive discussion of the invention. It is neither intended to identify key or critical elements of the invention nor to delineate the scope of the invention. Its purpose is to present in a simplified form Some concepts of the present invention are presented as a prelude to the more detailed description presented later.

According to a feature of the present disclosure, an ion source is provided, such as an ion source for an ion implantation system or various other processing systems. For example, the ion source includes an arc chamber having a body defining an interior region of the arc chamber. For example, one or more liners are operably coupled to the body of the arc chamber, wherein the one or more liners generally define an exposed surface of the interior region of the arc chamber. For example, the exposed surface is configured to be exposed to, and at least partially confined, a plasma generated within the interior region of the arc chamber.

In one example, an electrode such as a repeller is also proposed, wherein the electrode includes a shaft portion having a first diameter. The shaft portion passes through one of the main body and the one or more liners, wherein the electrode is electrically isolated from the main body. In one example, the one of the one or more liners includes a flat plate having a first surface, the first surface having a recess, and the recess has a second surface defined in the recess. A hole is further defined through the recess, wherein the hole is configured to pass through the shaft through the hole. For example, the hole has a second diameter larger than the first diameter, and defines an annular gap between the plate and the shaft portion. In addition, the plate includes a lip extending from the second surface towards the first surface, wherein the lip surrounds the hole in the recess and generally prevents particulate contamination from entering the gap. In another example, the aforementioned depressions are not present, and the lip extends outwardly from the first surface.

According to one example, the second surface is recessed from the first surface by a first distance, wherein the lip extends from the second surface toward the first surface by a second distance. One or more of the first surface and the second surface may be generally planar. in a special non-limiting In one example, the first distance is approximately twice the second distance. In another example, the aforementioned lip includes a third surface adjacent to a periphery of the hole. The third surface can also be generally planar, but various other configurations can also be envisaged, such as a circular or crystalline surface. In one example, the depression is generally U-shaped when viewed along an axis of the hole.

In yet another example, the aforementioned plate defines a bottom surface of the interior region of the arc chamber, wherein the lip generally prevents gravity from allowing particulate contaminants to enter the gap.

In yet another example, the lip has a third diameter associated therewith. The electrode described above may include a repeller having a head exposed to plasma generated within the interior region of the arc chamber, wherein the head has a fourth diameter. In one example, the fourth diameter is larger than the third diameter.

According to various other examples, an ion source processing chamber is provided having an electrode including a shaft portion and a head portion. A liner is further provided to the ion source processing chamber, wherein the liner has a hole therethrough, and wherein the electrode passes through the hole and defines an annular gap between the shaft portion and the hole . For example, the liner further includes a recess having a lip extending from the recess to generally surround the hole and generally prevent particulate contaminants from passing through the hole.

In another example, the aforementioned electrode includes a repeller device, wherein the repeller device includes a repeller electrode operably coupled to the shaft portion. A diameter of the repeller electrode is, for example, larger than a diameter of the hole, and wherein a diameter of the shaft portion is smaller than the diameter of the hole. In another example, a diameter of the lip body is between the diameter of the repeller electrode and the diameter of the hole.

Accordingly, the following description and the accompanying drawings set forth in detail certain exemplary features and implementations of the present invention. These represent but a few of the many ways in which the principles of the present invention may be employed.

100: Ion source

102: Surface

103: Internal Components

104: Cathode

106: Repeller

108: Arc Chamber

110: Side Wall

112: Lining

114: Pollutants

115: Replaceable Components

116: Subject

118: Gap

119: Partial zoom view

120: Bottom lining

122: Sag

124: Hole

126: Shaft

200: ion source

202: Arc Chamber

204: Bottom lining

206: Annular gap

208: Electrodes

210: Subject

212: Inner area

214: Lining

216: Exposed Surface

218: Shaft

220: first diameter

222: Tablet

224: First Surface

226: Sag

227: Bottom View

228: Second Surface

229: Section

230: Hole

232: Second Diameter

234: lip

236: First Distance

238: Second Distance

240: Third Surface

242: Peripheral

244: Axis

246: Third Diameter

248: Repeller

250: head

252: Fourth Diameter

254: Particulate Pollutants

1 illustrates a perspective view of an exemplary ion source and arc chamber with a liner.

Figure 2 is an enlarged view of a portion of Figure 1 showing the arc chamber with an inner liner but without a raised lip.

3 illustrates a perspective view of an exemplary ion source liner.

4 illustrates a perspective view of an ion source and arc chamber having a liner with a raised lip in accordance with some examples of the present disclosure.

5 is an enlarged view of a portion of FIG. 4 showing an arc chamber with a liner having a raised lip in accordance with some examples of the present disclosure.

6 illustrates a plan view of an arc chamber of an exemplary ion source having a liner with a raised lip, according to some examples of the present disclosure.

7 illustrates a perspective view of an exemplary ion source liner having a raised lip in accordance with some examples of the present disclosure.

8 illustrates a bottom plan view of an exemplary ion source liner in accordance with some examples of the present disclosure.

9 illustrates a cross-sectional view of FIG. 8 showing an ion source liner having a raised lip in accordance with some examples of the present disclosure.

The present invention generally relates to a method by having an ion source liner with a protrusion A system, apparatus, and method for reducing maintenance and increasing productivity of an ion source. Based on the foregoing, the present invention will be described below with reference to the drawings, wherein like reference numerals may be used throughout the text to refer to like elements. It should be understood that the descriptions of these features are exemplary only and should not be construed in a limiting sense. In the following description, for the purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the relevant art that the present invention may be practiced without these specific details.

An ion source (often referred to as an arc ion source) produces an ion beam for use in an implanter, and may include heating a filament cathode to generate ions that are shaped into a suitable ion beam for wafer processing. For example, US Patent No. 5,497,006 to Sferlazzo et al. discloses an ion source having a cathode supported by a susceptor positioned relative to a gas-enclosed chamber for ejecting ionized electrons into the gas-enclosed chamber. The cathode of the aforementioned Sferlazzo et al. document is a tubular conductive body with an end cap extending partially into the gas-enclosed chamber. A filament is supported within the tubular body and emits electrons which, through electron bombardment, heat the end cap, thereby ejecting ionized electrons in the form of thermions into the gas enclosure.

Extraction electrodes, such as those disclosed in US Pat. No. 6,501,078 to Ryding et al., for example, are used substantially with an ion source to extract an ion beam therefrom, formed in an enclosed chamber The ions are extracted through an exit aperture located on a front face of the ion source. A first apertured source electrode is formed on the front side of the ion source, which is at the potential of the ion source. The extraction electrodes typically include an apertured suppressor electrode and an apertured ground electrode aligned with the first apertured source electrode (sometimes referred to as an extraction electrode) to allow the ion beam from the ion source to pass through in. In preferred embodiments, each opening has an elongated slot configuration. Typically, ceramic insulators are loaded to suppress and Between the ground electrodes, the two electrodes are electrically insulated. The ground electrode limits the propagation of the electric field between the ground electrode and the ion source into the area of the lower end of the ground electrode. The suppressor electrode is biased by a voltage supply at a negative potential relative to ground and operates to prevent electrons in the ion beam at the downstream end of the ground electrode from being drawn into the extraction region and into the ion source.

An exemplary system for electrode voltage modulation in an ion source extraction electrode apparatus is described in US Patent No. 9,006,690, commonly owned by Colvin et al., and a method for reducing particulate contamination in an ion implantation system is described in Co-owned US Patent Application Publication No. 2011/0240889 to Colvin et al., the entire contents of which are incorporated herein by reference.

The present disclosure provides an apparatus configured to increase utilization and reduce downtime of an ion source processing chamber in an ion implanter. It should be understood, however, that the apparatus of the present disclosure may also be implemented in other semiconductor processing equipment, such as CVD, PVD, MOCVD, etching equipment, and various other semiconductor processing equipment, and all such embodiments are considered to fall within the scope of within the scope of this disclosure. The apparatus of the present disclosure advantageously increases the length of use of the source processing chamber between preventive maintenance cycles, and thus increases the overall productivity and longevity of the system.

An ion source (also known as an ion source processing chamber) can be used in an ion implantation system, and can use refractory metals (tungsten (W), molybdenum (Mo), tantalum (Ta), etc.) and Graphite is constructed to provide adequate high temperature performance, where these materials are generally acceptable to semiconductor wafer producers. An ion source gas is used within the ion source processing chamber, wherein the ion source gas can be conductive or not in nature. However, once the ion source gas bursts or is ejected from device fragmentation, the by-products of the ionized gas can be quite corrosive.

An example of an ion source gas is boron tri-fluoride (BF ₃ ), which can be used as a feed gas to generate boron 11 or BF ₂ ion beams in an ion implantation system. During the ionization of the BF molecule, it generates _three free fluorine groups. Refractory metals such as molybdenum and tungsten can be used to construct or line the ion arc source processing chamber to maintain its structural integrity at an operating temperature of about 700°C. However, refractory fluorides are volatile and have very high vapor pressures, even at room temperature. Fluorine radicals formed within the ion source processing chamber attack metal tungsten (or molybdenum, or graphite) and form tungsten hexafluoride (WF ₆ ) (or molybdenum or carbon fluoride): WF ₆ → W ⁺ +6 F ^- (1) or (MoF ₆ → Mo ⁺ +6 F ^- ) (2)

The tungsten hexafluoride will basically decompose above the hot surface. For example, in an ion source 100 shown in Figure 1, tungsten hexafluoride or other generating materials can decompose on surfaces 102 of various internal components 103 of the ion source, such as an arc chamber associated with the ion source 108 on the surface of a cathode 104, a repeller 106 and arc slit optics (not shown). This is referred to as a halogen cycle, as shown in equation (1), but the resulting species may also precipitate and/or condense back to the sides of the arc chamber 108 in the form of a contaminant 114 (eg, solid particulate contamination). Wall 110 or liner 112, and over the arc slit. For example, the liners 112 include a replaceable member 115 operably coupled to a body 116 of the arc chamber 108, wherein the liners are constructed of graphite or various other materials. For example, the above-described replaceable member 115 provides a wear surface that can be easily replaced after the arc chamber 108 has been in operation for a period of time.

Another source of contaminants 114 deposited on internal components 103 is generated from cathode 104 (eg, a cathode composed of tungsten or tantalum) when the cathode is indirectly heated, which is used to initiate and maintain Ion source plasma (eg, a thermionic electron emission). for example In other words, the indirectly heated cathode 104 and the repeller 106 (eg, an anti-cathode) are at a negative potential relative to the body 116 of the arc chamber 108, and both the cathode and the repeller are permeable through The ionized gas is sputtered. For example, the repeller 106 may be constructed from tungsten, molybdenum, or graphite. Yet another source of contaminant species 114 deposited on interior components 103 of arc chamber 108 is the dopant material (not shown) itself. Over time, the deposited films of these contaminants 114 may become stressed and then delaminate, thereby shortening the lifetime of the ion source 100 .

Surface conditions play an important role between a substrate and the thin film deposited thereon. For example, the London dispersion force describes the interaction between transient bipolar or multipoles associated with different parts of matter, explaining a major part of the attractive van der Waals force . These results have major implications in pursuing a better understanding of atomic and molecular adsorption to different metal substrates. A multi-order model integrating first-principles calculations and kinetic rate equation analysis showed a large reduction in the accretion temperature from 1000°C to 250-300°C.

Since the formation of strong atomic bonds within the interfacial region is unlikely to occur, differences in thermal expansion coefficients, high power and Thermal cycling during transitions between low-power ion beams, and decomposition of implant materials within uneven plasma boundaries can cause premature failure. Residual stresses in these deposits are of two types: one is due to defects during film growth; the other is due to mismatches between the thermal expansion coefficients of the substrate and the deposited film.

As the film thickness of the contaminant 114 increases, the extensional and/or compressive stress will reach a critical level at the interface with the substrate, so that peeling or delamination may occur within the ion source 100 . When such delamination of the contaminant 114 occurs, the contaminant that is delaminated may fall in and pass through A gap 118 defined between the repeller 106 and the liner 112 of the body 116 of the arc chamber 108, as shown in the enlarged partial view 119 of FIG. Electrical coupling between the repeller and the body of the arc chamber.

3 illustrates a bottom liner 120 provided in the ion source 100 of FIGS. 1 and 2, wherein the bottom liner includes a recess 122 and a hole 124, and wherein the hole is formed for to receive a shaft portion 126 of the repeller 106 in FIGS. 1 and 2 . In this regard, the aforementioned indispensable gap 118 is provided between the shaft portion and the bottom liner 120 . It should be noted, however, that the recess 122 is generally planar to accommodate the repeller 106 in the bottom liner 120 of FIG. 3 . As shown in FIGS. 1 and 2 , a head 128 of the repeller 106 covers a line of sight to the gap 118 between the shaft portion 126 of the repeller and the main body 116 of the arc chamber 108 . However, fine particles of contaminant 114 may still fall into recess 122 and subsequently enter gap 118 between shaft portion 126 and bottom liner 120 . These contaminants 114, which are conductive and disposed in the gap 118, can electrically short the biased repeller 106 to the body 116 of the arc chamber 108, thereby causing an unscheduled maintenance and/or The plasma is unstable, which in turn affects the quality of the ion beam formed from it.

Based on the above, FIGS. 4 and 5 illustrate an ion source 200 of the present disclosure having structures and components somewhat similar to the ion source 100 of FIGS. 1 and 2; however, the ion source 200 of FIGS. 4 and 5 An exemplary arc chamber 202 is included having a bottom liner 204 configured to substantially prevent contaminants from entering an annular gap between an electrode 208 of the arc chamber and the bottom liner 206, thereby substantially avoiding premature failure of the ion source.

According to an exemplary feature, a body 210 of the arc chamber 202 generally defines an interior region 212 of the arc chamber. Additionally, one or more liners 214 are operably coupled to the arc The aforementioned body 210 of the chamber 202, wherein the one or more liners generally define an exposed surface 216 of the aforementioned arc chamber interior region 212. For example, the one or more liners 214 include at least the bottom liner 204 . It should be noted that although the term "bottom" is currently used to refer to the bottom liner 204, the bottom liner does not necessarily have to be positioned at a lowermost location of the arc chamber 202. For example, the exposed surface 216 is configured to expose, and at least partially confine, a plasma (not shown) generated within the interior region 212 of the arc chamber 202 as described above.

According to one example, the electrode 208 includes a shaft portion 218 having a first diameter 220 shown in FIG. 6 , wherein the shaft portion passes through the body 210 and the bottom liner 204 . Electrode 208 is electrically isolated from body 210, as will be discussed below, wherein bottom liner 204 includes a plate 222 having a first surface 224 with a recess 226 defined thereon. For example, the recess 226 has a second surface 228 defined therein, and a further hole 230 is defined through the recess, as shown in more detail in FIGS. 6 and 8 . FIG. 8 shows a bottom view 227 of the bottom liner 204, and FIG. 9 shows a cross-section 229 of the bottom liner, eg, in which holes 230 are formed to pass through the holes through the electrodes 208 in FIGS. 4-5. Shaft portion 218 . The hole 230 has a second diameter 232 which is larger than the first diameter 220 of the shaft portion 218 in FIG. 6 . Accordingly, the annular gap 206 is defined between the plate 222 and the shaft portion 218 so as to electrically insulate the shaft portion from the bottom liner 204 .

According to the present disclosure, the plate 222 further includes a lip 234 extending from the second surface 228 toward the first surface 224 . In this regard, the lip 234 generally surrounds the hole 230 in the recess 226 in the bottom liner 204, while leaving an annular gap 206 between the plate 222 and the shaft portion 218 of the electrode 208 for the passage therebetween. Electrical isolation. Thus, the lip 234 generally prevents particulate contamination from entering the annular gap 206 by gravity, thereby preventing the main body of the electrode 208 and the arc chamber 202 Electrical short between body 210 and bottom liner 204 .

According to an example, as shown in FIG. 9 , the second surface 228 is recessed from the first surface 224 by a first distance 236 . In this example, the lip 234 extends a second distance 238 from the second surface 228 toward the first surface 224 . In this example, the first distance 236 is approximately twice the second distance 238, but these distances may vary with the design of the electrodes 208 in FIGS. 5-6 or other design criteria. As shown in FIG. 9 , one or more of the first surface 224 and the second surface 228 may be generally planar. However, although not shown, one or more of the first surface 224 and the second surface 228 may be sloped or have a curvilinear appearance, and all such appearances should be considered to fall within the scope of the present disclosure within the scope.

According to another example, the aforementioned lip 234 includes a third surface 240 adjacent to a periphery 242 of the hole 230 in FIG. 8 . In one example, the third surface 240 is generally planar, as shown in FIG. 9 . In addition, according to another example, when viewed along an axis 244 of the hole 230 , the aforementioned recess 226 is generally U-shaped, as shown in FIG. 7 .

According to yet another example, the aforementioned lip 234 has a third diameter 246 associated therewith, as shown in FIG. 9 . For example, electrode 208 of FIG. 6 may include a repeller 248 (sometimes referred to as a counter-cathode) located above the bottom of arc chamber 202. For example, the repeller 248 has a head 250 that is exposed to plasma (not shown) generated within the interior region 212 of the arc chamber 202, wherein the head has a fourth diameter 252, and wherein The fourth diameter is larger than the third diameter 246 of the lip 234 of FIG. 9 .

4-6, the plate 222 defines a bottom surface 216 in the interior region 212 of the arc chamber 202, wherein the lip 234 generally prevents the ingress of particulate contaminants 254 by gravity Annular gap 206 . Thus, delamination from within arc chamber 202 The particulate contamination 254 will generally fall onto the bottom surface 216 due to gravity.

Although the repeller 106 may obscure the view to the gap 118 between the electrodes of FIG. 2 and the body 116 of the arc chamber 108, the fine particulate matter 114 will eventually succeed in entering the gap. However, the lip 234 in the arc chamber 202 of FIGS. 4-6 generally prevents particulate contamination 254 from entering the gap 206 . In addition, the lip 234 of the present disclosure provides a reduction in process gas leakage through the gap 206 because the raised lip structure reduces conduction. This highly volatile and typically conductive gas will coat and shorten the life of any insulator used in the arc chamber construction.

In another example, although not shown, the bottom liner may be a flat plate with raised lips extending from the first surface around the repeller shaft, and may have the same Similar or different appearance. Based on the above, a lip or raised portion on the arc chamber bottom liner will prevent tiny particles of matter scattered from the arc chamber liner from entering the gap between the repeller shaft and the arc chamber body. Scattering of these conductive species can short the biased repeller to the arc chamber body, resulting in an unscheduled maintenance and/or plasma instability, which in turn affects the quality of the ion beam.

While the invention has been shown and described above in terms of one or more preferred embodiments, it will be apparent to others skilled in the relevant art upon review and understanding of the drawings in this specification and appendix that equivalent variations will be devised. Build and modify. In particular, with respect to the various functions performed by the above-described components (components, devices, circuits, etc.), unless stated otherwise, the terms used to describe such components (including references to a "means") References) are intended to correspond to any component that performs the specified function of the component (ie, is functionally equivalent), even if the structure is not equivalent to a disclosed structure that performs the functions of the exemplary embodiments of the invention illustrated herein. In addition, although a particular feature of the present invention A feature is disclosed with reference to only one of some embodiments, but the feature may be combined with one or more other features of the other embodiments as required and advantageous for any particular or particular application.

202‧‧‧Arc Chamber

206‧‧‧Annular gap

208‧‧‧Electrode

210‧‧‧Subject

212‧‧‧Interior area

214‧‧‧Inner lining

216‧‧‧Exposed surface

218‧‧‧Shaft

220‧‧‧First diameter

222‧‧‧Tablet

224‧‧‧First surface

226‧‧‧Depression

228‧‧‧Second surface

230‧‧‧holes

232‧‧‧Second diameter

234‧‧‧Lipoid

246‧‧‧Third diameter

248‧‧‧Repeller

250‧‧‧Head

252‧‧‧4th diameter

Claims (16)

An ion source liner comprising: a flat plate having an exposed surface configured to be exposed to and at least partially confined to a plasma generated within an ion source, wherein the exposed surface is A first surface definition, wherein the plate includes a hole through the first surface, and wherein the hole is configured to pass an electrode through the hole, leaving an annular gap between the electrode and the hole between the holes, and wherein a lip surrounds the hole and extends outward from the first surface, wherein the first surface has a depression further defined therein, wherein the depression includes a second surface, the first surface Two surfaces are recessed from the first surface a first distance, and wherein the lip extends a second distance from the second surface toward the first surface, and wherein one of the first surface and the second surface or Most are sloping or have a curvilinear appearance. The ion source liner of claim 1, wherein the first distance is about twice the second distance. The ion source liner of claim 1, wherein the lip includes a third surface adjacent to a periphery of the hole. The ion source liner of claim 3, wherein the third surface is substantially planar. The ion source liner of claim 1, wherein the depression is generally U-shaped when viewed along an axis of the hole. An ion source, comprising: an arc chamber having a body defining an interior region of the arc chamber; one or more liners operatively coupled to the body of the arc chamber, wherein the one or more liners generally define an exposed surface of the interior region of the arc chamber, and wherein the exposed surface is an electrode including a shaft portion having a first diameter, wherein the shaft portion passes through the body and one of the one or more liners, wherein the electrode is electrically isolated from the body, and wherein the one of the one or more liners comprises a flat plate having a first surface, the first The surface has a depression, the depression has a second surface defined therein, wherein a hole is further defined through the depression and is configured to pass the shaft portion, wherein the hole has a diameter larger than the first diameter and defines therein an annular gap between the plate and the shaft portion, and wherein the plate includes a lip extending from the second surface toward the first surface, wherein the lip a lip surrounds the hole in the recess and generally prevents particulate contamination from entering the annular gap, wherein the second surface is recessed a first distance from the first surface, and wherein the lip extends from the second The surface extends a second distance toward the first surface, and wherein one or more of the first surface and the second surface is sloped or has a curvilinear appearance. The ion source of claim 6, wherein the first distance is about twice the second distance. The ion source of claim 6, wherein the lip includes a third surface adjacent to a periphery of the hole. The ion source of claim 8, wherein the third surface is substantially planar. The ion source of claim 6, wherein the recess is generally U-shaped when viewed along an axis of the hole. 6. The ion source of claim 6, wherein the plate defines a bottom surface in the interior region of the arc chamber, and wherein the lip substantially prevents particulate contaminants from falling into the annular gap by gravity . 6. The ion source of claim 6, wherein the lip has a third diameter associated therewith, wherein the electrode includes a repeller having a head exposed to the The plasma within the interior region of the arc chamber, wherein the head has a fourth diameter, and wherein the fourth diameter is greater than the third diameter. An ion source processing chamber, comprising: an electrode having a shaft portion and a head portion; and a lining having a hole therethrough, wherein the electrode passes through the hole and defines an annular gap in the shaft portion and the hole, and wherein the liner includes a depression having a lip extending from the depression to generally surround the hole and generally prevent particulate contaminants from passing through the hole hole, wherein the liner includes a first surface, wherein the recess includes a second surface, and wherein the lip extends a distance from the second surface toward the first surface, and wherein the first surface and the first surface One or more of the two surfaces is sloped or has a curvilinear appearance. The ion source processing chamber of claim 13, wherein the electrode comprises a repeller device, wherein the repeller device comprises a repeller electrode operatively coupled to the shaft portion, and wherein the repeller The diameter of the electrode is larger than the diameter of the hole, and the diameter of the shaft is smaller than the hole The diameter of the hole. The ion source processing chamber of claim 14, wherein the diameter of the lip is between the diameter of the repeller electrode and the diameter of the hole. The ion source processing chamber of claim 13, wherein the lip extends about half the distance from the first surface toward the second surface.

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