WO2005020265A2

WO2005020265A2 - Sputtered contamination shielding for an ion source

Info

Publication number: WO2005020265A2
Application number: PCT/US2004/027189
Authority: WO
Inventors: David Matthew Burtner; Daniel E. Siegfried; Richard Blacker; Valery Alexeyev; John Keem; Vsevolod Zelenkov; Mark Krivoruchko
Original assignee: Veeco Instruments, Inc.
Priority date: 2003-08-20
Filing date: 2004-08-20
Publication date: 2005-03-03
Also published as: WO2005020265A3

Abstract

Shielding (108) associated with an ion source (102), such as an anode layer source, reduces the amount and/or concentration of sputtered contaminants impinging and remaining on the surface of a target substrate (110). While passing the ion beam through to the target substrate (110), shielding (108) can reduce the total amount of sputtered contaminants impinging the substrate (110) before, during, and/or after passage of the substrate (110) through the envelope of the etching beam. Particularly, a shield configuration (108) that blocks the contaminants from impinging the substrate (110) after the substrate (100) passes through the etching beam (i.e., outside of the envelope of the etching beam) yields a higher quality substrate (110) with reduced substrate (110) contamination.

Description

Related Applications [0001] This application claims benefit of U.S. Provisional Application No.

60/496,886, entitled "Sputtered Contamination Shielding for an Ion Source" and

filed August 20, 2003, incorporated herein by reference for all that it discloses and

teaches.

Technical Field [0002] The invention relates generally to ion sources, and more particularly

to shielding for an ion source.

Background [0003] Generally, an ion source is a device that ionizes gas molecules and

focuses, accelerates, and emits the ionized gas molecules and/or atoms in a beam

for a variety of technical and industrial applications. For example, ion sources

may be used as thrusters on space craft. Ion sources are also used in

semiconductor material and device processing, optical filter processing, and

metrology, among other applications. Common uses of ion sources include

without limitation cleaning, assisting deposition (by chemically or physically

activating), polishing, etching and/or depositing of thin- film coatings. Typically, a

substrate is passed through an ion beam (e.g., an etching beam) for such

processing. [0004] An anode layer source (ALS) typically refers to a Hall-current type

ion source having a grounded cathode and a DC-biased anode. The working gas is

fed into an ionization region in the vicinity of the anode and the cathode, where

the combination of electric and magnetic fields in this region ionizes the molecules

of the working gas and accelerates each ion away from the ionization region

toward a target. The ionization region generally forms a closed-loop (e.g., a race

track shape) in the face of the ion source. The shape of this closed-loop "race

track" may be round, oval, linear with rounded ends, or many other closed shapes.

[0005] One benefit to an ALS is that an ALS does not require a hot cathode

electron source (e.g., filament cathode, hollow cathode, or RF neutralizer) with a

separate power supply to sustain the plasma. ALS cathodes are passive, cold

cathodes, typically made of steel. The cathodes also function as pole pieces for

the ALS magnetic circuit. The cold cathodes do not actively emit electrons, but

ions bombarding the cathodes release secondary electrons that help to sustain the

discharge.

[0006] One problem with an ALS, however, is that the ions striking the

cathodes can also sputter material from the cathodes. The sputtered cathode

material may enter the process as a contaminant. Such cathodes are typically steel

or magnetic stainless steel, so the primary contaminant is iron, although other

contaminants may also exist. The sputtered material tends to emit across a wide

range of angles. As a result, the sputtered material tends to impinge the substrate

surface outside the envelope of the etching beam as well as inside the envelope of the etching beam. Depending on the type of ion source, the operating regime, and

the application, there may be other ion source electrodes or adjacent components

that also sputter in a similar matter and contribute to substrate contamination.

[0007] Most contaminants impinging the substrate surface prior to and

during the passing of the substrate through the etching beam are etched away by

the beam. However, the contaminants that impinge the surface of the substrate

after the substrate has passed through the etching beam remain as contaminants.

In other words, a substrate tends to acquire a new layer of contaminants after

exiting the envelope of the ion beam. Therefore, for example, etching a substrate

using an ALS may yield an etched substrate having an unacceptable concentration

of iron contaminants sputtered from the ALS itself.

Summary [0008] Implementations described and claimed herein solve the discussed

problems by providing shielding associated with an ion source, such as an ALS.

The shield configuration allows the etching ions to pass to the substrate and

effectively blocks sputtered contaminants from impinging the target substrate

outside the envelope of the etching beam.

[0009] Such shielding associated with an ion source reduces the number of

sputtered contaminants impinging and remaining on the surface of a target

substrate. While passing the ion beam through to the target substrate, shielding

can reduce the total number of sputtered contaminants impinging the substrate before, during, and/or after passage of the substrate through the envelope of the

etching beam. Particularly, a shield configuration that blocks the contaminants

from impinging the substrate after the substrate passes through the etching beam

(i.e., outside of the envelope of the etching beam) yields a higher quality substrate

(i.e., with lower contamination levels).

[0010] In one implementation, an ion source system for processing a

substrate along a substrate location path is provided. An ion source generates an

ion beam. A shield is positioned between the ion source and the substrate location

to pass the ion beam to the substrate while blocking sputtered contaminants from

impinging the substrate.

[0011] In another implementation, a shielding system positionable between

an ion source and a substrate location is provided. The shielding system passes an

ion beam from an ion source to impinge a substrate on the substrate location while

blocking sputtered contaminants from impinging the substrate.

[0012] In yet another implementation, a method of processing a substrate is

provided. An ion beam is generated and sputters ions from an ion source having a

cathode, the ion beam defining an envelope. The substrate passes through the

envelope. Sputtered contaminants are sputtered from the cathode by the sputtering

ions. The sputtered contaminants are blocked from impinging the substrate

outside of the envelope of the ion beam. [0013] In yet another embodiment, an ion source system includes an ion

source; and means for passing an ion beam from the ion source to impinge a

substrate while blocking sputtered contaminants from impinging the substrate.

Brief Description of the Drawings [0014] FIG. 1 illustrates a cross-sectional schematic view of an ion source

with exemplary emitter shields.

[0015] FIG. 2 illustrates a more detailed cross-sectional schematic view of

an ion source with exemplary emitter shields.

[0016] FIG. 3 illustrates a cross-sectional schematic view of an ion source

with exemplary substrate shields.

[0017] FIG. 4 illustrates a more detailed cross-sectional schematic view of

an ion source with exemplary substrate shields.

[0018] FIG. 5 illustrates a face of an ion source with exemplary emitter

shields.

[0019] FIG. 6 illustrates a perspective view of the ion source of FIG. 5 with

exemplary emitter shields.

[0020] FIG. 7 illustrates a face of another ion source with exemplary emitter

shields.

[0021] FIG. 8 illustrates a perspective view of the ion source of FIG. 7 with

exemplary emitter shields. Detailed Description of the Invention [0022] Using shielding in association with an ion source can reduce the total

number of sputtered contaminants striking and remaining on the surface of a target

substrate. A shield configuration can block the sputtered contaminants from

impinging the substrate outside the envelope of the ion beam. Many, but not all,

contaminants that impinge the substrate during (and prior to) the passage of the

substrate through the envelope of the etching beam are etched away from the

substrate by the beam. In one implementation, blocking such contaminants from

impinging the substrate surface after the substrate passes through the etching beam

(i.e., outside of the envelope of the etching beam) significantly reduced

contamination of the substrate surface, although generally reducing the number of

sputtered contaminants reaching the surface of the substrate improves substrate

quality as well (e.g., resulting in about a 50% reduction in substrate

contamination).

[0023] FIG. 1 illustrates a cross-sectional schematic view of an ion source

with exemplary emitter shields, which are adjacent to the ion source. An ion

source processing system 100 includes an ion source 102, and emitter shields 104,

106, and 108. The target of the processing is a substrate 110, which is positioned

or passed at some distance from the emission face 101 of the ion source 102. The

ion source 102 produces an ion beam on an ion beam axis 114, where an ion beam

envelope is defined by arrows 112 and the ion beam axis 114 is substantially

perpendicular to the emission face 101. The substrate 110 is passed through the ion beam envelope 112, substantially perpendicular to the ion beam axis 114,

although geometries with non-peφendicular ion beam emission and/or

impingement are also contemplated. In addition, ion beam emission intensity and

direction may be different for different portions or sides of the ionization region.

In a typical configuration, multiple substrates are passed sequentially through the

ion beam for processing along this perpendicular path, although other

configurations may involve one or more stationary substrates.

[0024] In one exemplary type of ALS, called a linear ALS, the ion beam is

linear (e.g., long and narrow) as defined by a closed oval ionization region or

channel with long, straight sides (see, for example, FIGs. 5 and 6). Typical

applications of linear ALS systems include processing large flat substrates with

substrate motion generally perpendicular to the longitudinal axis of the beam (i.e.,

perpendicular to the straight section of the ionization channel). Linear ALS

systems, other types of ALS systems, and other types of ion beam sources may

benefit from the described technology.

[0025] Some generated ions (i.e., sputtering ions) impinge the cathodes 116

and 117, causing cathode material to sputter (shown by arrows 118) from the

cathodes 116 and 117. The sputtered material can enter the process as a

contaminant on the surface of the substrate 110. For example, absent the shields

104, 106, and 108, when the substrate 110 is in positions 122 and 124, sputtered

material from the cathodes 116 and 117 may impinge the substrate 110, thereby

contaminating the surface of the substrate 110. In addition, regardless of the presence of the shields 104, 106, and 108, sputtered material from the

cathodes 1 16 and 117 may impinge the substrate 110 while passing through the

width 120 of the ion beam on the substrate path. The ion beam width is dependent

upon the envelope defined by edges of the ion beam and the distance between the

ionization region of the ion source and the substrate path.

[0026] A substantial amount of the sputtered contaminants impinging the

surface of the substrate 110 before (e.g., at position 122) and during passage of the

substrate 110 through the ion beam is etched away by the beam. Some such

contaminants remain. Therefore, reducing the total amount of contaminants

impinging the surface of the substrate can improve the quality of the substrate.

Furthermore, any contaminants impinging the surface of the substrate 110 after

passage through the far edge of the ion beam envelope 112 (e.g., see general

location referenced by arrow 113) remain on the surface because none are etched

away. Therefore, reducing the amount of contaminants impinging the surface of

the substrate after passage through the ion beam can reduce substrate

contamination.

[0027] By positioning shields 104, 106, and 108 to block sputtered

contaminants that are directed outside of the envelope of the ion beam, the

sputtered contaminant count is dramatically reduced on the surface of the substrate

110. The outside shield 104 extends upright (i.e., at a greater than 0^° angle to a

90° angle) from the face of the ion source 102 and is positioned outside and along

one of the long channels of the ionization region of the ion source. The outside shield 104 blocks sputtered contaminants emitted to the left in FIG. 1 from the

cathodes 116 of the ion source 102. The end point 126 of the outside shield 104 is

positioned to pass a substantial amount of the ion beam while blocking sputtered

contaminants emitted outside the ion beam envelope.

[0028] The inside shield 106 blocks sputtered contaminants emitted to the

right in FIG. 1 from the cathodes 116 of the ion source 102 and to the left in FIG.

1 from the cathodes 117 of the ion source 102. The inside shield 106 extends

upright (e.g., at a greater than 0° angle to a 90° angle) from the emission face 101

of the ion source 102 and is positioned between the long channels of the ionization

region of the ion source. The end point 128 of the inside shield 106 is positioned

to pass a substantial amount of the ion beam while blocking sputtered

contaminants emitted outside the inside edge portions of the envelope of the ion

beam emitted from cathodes 116 and 117.

[0029] The outside shield 108 blocks sputtered contaminants emitted to the

right in FIG. 1 from the cathodes 117 of the ion source 102. The outside shield

108 extends upright (e.g., at a greater than 0^° angle to a 90° angle) from the

emission face 101 of the ion source 102 and is positioned outside and along the

other long channel of the ionization region of the ion source. The end point 130 of

the outside shield 108 is positioned to pass a substantial amount of the ion beam

while blocking sputtered contaminants emitted outside the ion beam envelope.

[0030] In addition, end shields (not shown in FIG. 1 , but examples may be

seen in FIGs. 5-8) may also be employed to block sputtered material emitted from the ends of an ALS (e.g., the curved end portions of the ionization channels 502

and 702 of ion sources 500 and 700, respectively, in FIGs. 5-8). It should be

understood that the inside shields, the outside shields, and the end shields may or

may not be physically attached to the ion source itself.

[0031] In some operating conditions, the shields may be sputtered the by

ion beam (e.g., depending upon the height, shape, location, and composition of the

shields and the shape and intensity of the ion beam). As such, shields may be

fabricated out of materials that are not process contaminants, such as titanium in a

titanium-oxide deposition process, and/or that have a very low sputter yield

(collectively "process-compatible" materials). In addition to shield materials

being sputtered into the process, some of the cathode or anode materials may be

initially sputtered from the ion source to impinge the shield and then be "re-

sputtered" from the shield into the process. As such, shields may be positioned

with an inward tilt, provided with a louvered design, or manufactured with a

honeycomb or similar structured material to trap sputtered contaminants to reduce

forward sputtering of contaminant material.

[0032] FIG. 2 illustrates a more detailed cross-sectional schematic view of

an ion source with exemplary emitter shields. The system 200 includes a closed-

field ion source 202 and emitter shields 204, 206, and 208, which extend outward

from the face of the ion source 202. (An open-field anode layer ion source may be

employed in an alternative implementation. Also, implementations may be

applied to end-Hall ion sources and various other ion sources. Moreover, ion sources where the edges of the contaminant distribution zone (e.g., 118 in FIG. 1)

is broader than the edges of the ion beam (e.g., beam 112 in FIG. 1) may gain

particular benefit from such described shielding. In addition, such ion source

beam shapes may vary and may include circular shapes, annular shapes, etc.) A

working gas is emitted behind the anode 210 through inlet 211, flows around the

anode 210, and is ionized at an ionization region 212 through interaction of an

electric field generated by the power source 214 and a magnetic field generated by

permanent magnets 215. The anode 210 is made of a non-magnetic material, such

as 300 series stainless steel. A cathode 216 is made of magnetic material, such as

carbon steel or 400 series stainless steel. The combination of the electric field and

the magnetic field creates the ions and accelerates them away from the ionization

region 212, as represented by dashed beam lines 218, toward a target (e.g., a

substrate).

[0033] However, some ions created at the ionization region 212 bombard

the surface of the cathode 216 near the ionization region 212 and, therefore,

sputter cathode material away from the ionization region 212, as represented by

the exemplary directional arrows 220 and 222. The sputtered material can enter

the ion beam process as a contaminant, such as by impinging the surface of the

substrate.

[0034] In some ion source applications, gases that can form some negative

ions as well as the usual positive ions, such as oxygen, may be used. These

negative ions can sputter the anode and result in sputtered anode material entering the process as a contaminant in a manner similar to that described herein for

cathode sputtering. As such, the shielding described herein may be used to block

anode sputtered contaminants and other contaminants as well.

[0035] As can be seen in FIG. 2, the sputtered material corresponding to

arrows 220 strikes the surfaces of the shields 204, 206, and 208, and is effectively

blocked from impinging the target. In contrast, the sputtered material

corresponding to the arrows 222 bypasses the shields 204, 206, and 208 and may

impinge the target. However, the sputtered material corresponding to the

arrows 222 remains within the envelope of the ion beam 218 and is therefore

substantially etched away from the substrate by the ion beam during processing.

[0036] Accordingly, the heights of the shields 204, 206, and 208 (relative to

the ionization region 212) are set to substantially block sputtered material that is

emitted outside the ion beam envelope 218, while substantially allowing the ion

beam (and sputtered material emitted within the ion beam envelope) to pass to the

target. Likewise, the widths of the shields 204, 206, and 208 (or the distances of

the shields 204, 206, and 208 from adjacent ionization regions) are set with at least

the same constraints.

[0037] FIG. 3 illustrates a cross-sectional schematic view of an ion source

with exemplary substrate shields, which are adjacent to the substrate path. An ion

source processing system 300 includes an ion source 302 and substrate shields 304

and 306. The target of the processing is a substrate 308, which is located or

passed at some distance from the emission face 301. The substrate 308 is passed through an ion beam (defined by dashed arrows 310). In a typical configuration,

multiple substrates are passed sequentially through the ion beam for processing

along this path parallel to the emission face 301, although non-parallel paths may

also be employed.

[0038] Some generated ions (i.e., sputtering ions) bombard the cathodes 312

and 314, causing cathode material to sputter (shown by solid arrows 316 and 318)

from the cathodes 312 and 314. As mentioned earlier, cathode sputtered

contaminants are just one type of contaminant material that may enter the process.

Other contaminant materials may also be sputtered off of other surfaces of the ion

source or enter the process through other means.

[0039] The sputtered material can enter the process as a contaminant on the

surface of the substrate 308. For example, absent the shields 304 and 306, when

the substrate is outside the ion beam envelope, sputtered material from the

cathodes 312 and 314 may impinge the substrate 308, thereby contaminating the

surface of the substrate 308. In addition, regardless of the presence of the

shields 304 and 306, sputtered material from the cathodes 312 and 314 may

impinge the substrate 308 while passing through the ion beam envelope.

However, a substantial amount of the sputtered contaminant impinging the surface

of the substrate 308 before and during passage of the substrate 308 through the ion

beam is etched away by the ion beam. However, any contaminant impinging the

surface of the substrate 308 after passage through the ion beam remains on the

surface. By positioning shields 304 and 306 to block sputtered contaminants that are directed outside of the ion beam envelope, the sputtered contaminant count

reaching the substrate is dramatically reduced on the surface of the substrate 308.

It should be understood, however, that such shields may be positioned along an

ion beam axis near to the substrate location, near to the emission face 301, or at

some distance in between the substrate location and the emission face 301.

[0040] FIG. 4 illustrates a more detailed cross-sectional schematic view of

an ion source with exemplary substrate shields. The system 400 includes an open-

field ion source 402, although a closed-field ion source may be employed in an

alternative implementation. The system 400 also includes substrate shields 404

and 406, which are positioned substantially parallel to the face of the ion

source 402 (although non-parallel configurations are also contemplated). A

working gas is emitted from the anode 408 and ionized at the ionization

region 410 through the interaction of an electric field generated by the power

source 412 and a magnetic field generated by permanent magnets 424. The

anode 408 is made of a non-magnetic material, such as 300 series stainless steel.

A cathode 414 is made of magnetic material, such as carbon steel or 400 series

steel. The combination of the electric field and the magnetic field creates the ions

and accelerates them away from the ionization region 410, as represented by

dashed beam lines 416, toward a target (e.g., a substrate). For open-field sources,

additional magnets and pole pieces may be used to provide an extended

acceleration zone to enhance low energy operation and stability. Sputtering of

these extended components can also be a source of contamination. [0041] However, some ions created at the ionization region 410 bombard

the surface of the cathode 414 near the ionization region 410 (as well as other

surfaces) and, therefore, sputter cathode material away from the ionization region

410, as represented by the exemplary directional arrows 418 and 420. The

sputtered material enters the ion beam process as a contaminant, such as by

reaching the surface of a substrate 422.

[0042] As can be seen in FIG. 4, the sputtered material corresponding to

arrows 418 strikes the surfaces of the shields 404 and 406, and is effectively

blocked from reaching the target substrate 422. In contrast, the sputtered material

corresponding to the arrows 420 bypasses the shields 404 and 406 and may

impinge the target substrate 422. However, the sputtered material corresponding

to the arrows 420 remains within the envelope of the ion beam 416 and is

therefore substantially etched away from the target substrate by the ion beam

during processing. Accordingly, the separation between the shields (404 and 406)

and the substrate path and the separation between and relative alignment between

the shields (404 and 406) and the ionization regions 410 are set to block sputtered

material that is emitted outside the ion beam envelope, while allowing the ion

target.

[0043] FIG. 5 illustrates a face of an ion source 500 with exemplary emitter

shields. FIG. 6 illustrates a perspective view of the ion source 500 of FIG. 5 with

exemplary emitter shields. An ion source 500 includes an oval ionization region 502 in which a working gas is ionized and from which ions are emitted. In

operation, the ion source 500 emits ions from the ionization region 502 in the form

of an ion beam. A substrate (not shown) is passed through the ion beam for

processing (e.g., at some distance from the face of the ion source). In an

exemplary embodiment, a substrate is transported along a path peφendicular to (or

some other angle relative to) the long axis of the ion source 500, which emits an

ion beam from the ionization region 502 toward the surface of the substrate as it

passes.

[0044] It should be understood that some benefits may result for a non-

peφendicular substrate path, including increasing power density, reducing

overspray on a source longer than the width of the substrate, and smoothing out

small longitudinal beam non-uniformities. There may also be benefits for a non-

peφendicular angle of emission from the ion source and/or a non-peφendicular

angle of ion impingement on the substrate. It should also be noted that the angle

of the beam may be modified dynamically during the emission. Benefits may also

be achieved from operating with the shields at some other electrical potential

relative to the ion source housing (e.g., electrical isolation/floating and/or active

biasing at a positive potential).

[0045] Emitter shields 504, 506, and 508 are positioned between the ion

source 500 and the path of the substrate along the long channel portions of the

ionization region 502. In various embodiments, one or two of the shields 504,

506, and 508 may be omitted. However, to best block sputtered contaminants from impinging the substrate surface after the substrate has passed through the ion

beam, one of the shields is maintained on the far edge of the ion source (i.e.,

farthest in the direction of substrate motion). Nevertheless, each shield, singly or

in combination with other shields, may decrease the total amount of sputtered

contaminants reaching or remaining on the surface of the substrate, thereby

improving substrate quality.

[0046] In the illustrated implementation, and in addition to emitter shields

504, 506, and 508, end shields 510 and 512 may be employed to block sputtered

contaminants from the rounded ends of the ion source 500. Each end shield 510

and 512 may be configured (e.g. shaped, placed and sized) to block all emitted

ions and sputtered contaminants emanating from the rounded ionization

region 502 region in the ends of the ion source 500. For example, the end

shields 510 and 512 may be much taller than the emitter shields 504, 506, and 508,

which are sized to substantially pass the ion beam and substantially block the

sputtered contaminants. Alternatively, the end shields 510 and 512 may be

positioned, sized, and shaped to pass a portion of the ion beam and to substantially

block the sputtered contaminants.

[0047] FIG. 7 illustrates a face of another ion source 700 with exemplary

emitter shields. FIG. 8 illustrates a perspective view of the ion source 700 of FIG.

7 with exemplary emitter shields. An ion source 700 includes an oval ionization

region 702 in which a working gas is ionized. In operation, the ion source 700

emits ions from the ionization region 702 in the form of an ion beam. A substrate (not shown) is transported through the ion beam for processing (e.g., at some

distance from the face of the ion source). In an exemplary embodiment, a

substrate is transported along a path peφendicular to the long axis of the ion

source 700, which emits an ion beam from the ionization region 702 toward the

surface of the substrate as it passes.

[0048] Emitter shields 704, 706, and 708 are positioned between the ion

source 700 and the path of the substrate along the long channel portions of the

ionization region 702, as discussed with regard to FIGs. 5 and 6. Likewise, in

various embodiments, one or two of the shields 504, 506, and 508 may be omitted.

[0049] In addition to emitter shields 704, 706, and 708, end shields 710 and

712 may be employed to block sputtered contaminants from the rounded ends of

the ion source 700. The end shields 710 and 712 are shaped to improve the

amount of the ion beam that is passed while substantially blocking the sputtered

contaminants. The rounded shape substantially matches the rounded shape of the

ionization region 702 at the ends of the ion source 700. In this configuration, the

size and positioning of the end shields 710 and 712 are set to substantially pass the

ion beam and to substantially block the sputtered contaminants from reaching the

substrate.

[0050] The above specification, examples and data provide a complete

description of the structure and use of exemplary embodiments of the invention.

However, other implementations are also contemplated within the scope of the

present invention, including without limitation shields having different shapes, sizes, and locations than those shown, as well as systems having one or more

shields and systems with or without one or more end shields. In addition, while

the description has described exemplary ion sources as ALSs, other ion sources

may be employed within the scope of the invention. Since many implementations

can be made without departing from the spirit and scope of the invention, the

invention resides in the claims hereinafter appended.

Claims

Claims WHAT IS CLAIMED IS:

1. An ion source system for processing a substrate along a substrate

location, the ion source system comprising: an ion source generating an ion beam; and a shield positioned between the ion source and the substrate location to pass

the ion beam to the substrate while blocking sputtered contaminants emanating

from the ion source from impinging the substrate.

2. The ion source system of claim 1 wherein the ion source includes a

cathode and generates sputtering ions, the sputtering ions sputtering the sputtered

contaminant from the cathode.

3. The ion source system of claim 1 wherein the ion source includes an

anode and generates sputtering ions, the sputtering ions sputtering the sputtered

contaminant from the anode.

4. The ion source system of claim 1 wherein the ion beam defines an

envelope and the shield blocks the sputtered contaminants outside the envelope of

the ion beam.

5. The ion source system of claim 1 wherein the ion beam defines an

envelope and the substrate location is defined for passing the substrate through the

envelope of ion beam.

6. The ion source system of claim 1 wherein the ion source has a face and

an ionization region, and the shield is positioned upright relative to the face of the

ion source between long channels portions of the ionization region.

7. The ion source system of claim 1 wherein the ion source has a face and

the shield is affixed to the ion source and is positioned upright relative to the face

of the ion source between long channel portions of an ionization region of the ion

source.

8. The ion source system of claim 1 wherein the ion source has a face and

the shield is positioned upright relative to the face of the ion source along and

outside a long channel portion of an ionization region of the ion source.

9. The ion source system of claim 1 wherein the ion source has a face and

of the ion source along and outside a long channel portion of an ionization region

of the ion source.

10. The ion source system of claim 1 wherein the ion beam defines an

envelope, the substrate location is defined for passing the substrate through the

envelope of ion beam, and the shield is positioned adjacent to the substrate location to block the sputtered contaminants from impinging the substrate on at

least a portion of the substrate location outside the envelope of the ion beam.

11. The ion source system of claim 1 wherein the ion source has a face, the

ion beam defines an envelope, the substrate location is defined for passing the

substrate through the envelope of ion beam, and the shield is positioned

substantially parallel to the face of the ion source and adjacent to the substrate

location to block the sputtered contaminants from impinging the substrate on at

least a portion of the substrate location outside the envelope of the ion beam.

12. The ion source system of claim 1 wherein the ion source includes an

ionization region and at least one end section containing an end portion of the

ionization region, the shield blocking sputtered contaminants emanating from the

end portion of the ionization region from impinging the substrate.

13. The ion source system of claim 1 wherein the sputtered contaminants

are sputtered from a surface of the ion source.

14. The ion source system of claim 1 wherein the ion source has an

emission face from which the ion beam is emitted toward the substrate location

and the emission face is parallel to a surface of the substrate.

15. The ion source system of claim 1 wherein the ion source has an

emission face from which the ion beam is emitted in a normal direction from the emission face toward the substrate location and the emission face is parallel to a

surface of the substrate.

16. The ion source system of claim 1 wherein the ion source has an

emission face from which the ion beam is emitted in a non-normal direction from

the emission face toward the substrate location and the emission face is parallel to

a surface of the substrate.

17. The ion source system of claim 1 wherein the ion source has an

emission face from which the ion beam is emitted toward the substrate location

and the emission face is not parallel to a surface of the substrate.

18. The ion source system of claim 1 wherein the ion source has an

emission face from which the ion beam is emitted in a normal direction to the

emission face toward the substrate location and the emission face is not parallel to

a surface of the substrate.

19. The ion source system of claim 1 wherein the ion source has an

emission face from which the ion beam is emitted in a non-normal direction to the

a surface of the substrate.

20. The ion source system of claim 1 wherein the shield is actively biased.

21. The ion source system of claim 1 wherein the shield is actively biased to

a positive potential.

22. The ion source system of claim 1 wherein the shield is electrically

isolated from the ion source.

23. The ion source system of claim 1 wherein the shield comprises a

process-compatible material.

24. The ion source system of claim 1 wherein the shield comprises a

contaminant-trapping material.

25. A shielding system positionable between an ion source and a

substrate location that passes an ion beam from an ion source to impinge a

substrate on the substrate location while blocking sputtered contaminants

emanating from the ion source from impinging the substrate.

26. The shielding system of claim 25 wherein the ion beam defines an

envelope and the sputtered contaminants are blocked outside the envelope of

the ion beam.

27. The shielding system of claim 25 wherein the sputtered contaminants

are sputtered from a cathode of the ion source.

28. The shielding system of claim 25 wherein the sputtered contaminants

are sputtered from an anode of the ion source.

29. The shielding system of claim 25 wherein the ion beam defines an

envelope and the substrate location is defined for passing the substrate through

the envelope of ion beam.

30. The shielding system of claim 25 wherein the ion source includes a

cathode and an ionization region that generates the ion beam and sputtering

ions, and the sputtering ions sputter the sputtered contaminant from the cathode

toward the substrate location.

31. The shielding system of claim 25 wherein the ion source has a face

and an ionization region, and the shielding system includes a shield positioned upright relative to the face of the ion source between long channels portions of

the ionization region of the ion source.

32. The shielding system of claim 25 wherein the ion source has a face

and an ionization region, and the shielding system includes a shield affixed to

the ion source and being positioned upright relative to the face of the ion source

between long channel portions of an ionization region of the ion source.

33. The shielding system of claim 25 wherein the ion source has a face

and an ionization region, and the shielding system includes a shield positioned

upright relative to the ion source along and outside a long channel portion of an

ionization region of the ion source.

34. The shielding system of claim 25 wherein the ion source has a face

and an ionization region, and the shielding system includes a shield affixed to

the ion source and being positioned upright relative to the ion source along and

outside and along a long channel portion of an ionization region of the ion

source.

35. The shielding system of claim 25 wherein the ion beam defines an

envelope, a substrate location is defined to pass the substrate through the

envelope of ion beam, and the shielding system includes a shield positioned

adjacent to the substrate location to block sputtered contaminants from

impinging the substrate on at least a portion of the substrate location outside an

envelope of the ion beam.

36. The shielding system of claim 25 wherein the ion source includes an

ionization region and at least one end section containing an end portion of the

ionization region, and the shielding system includes an end shield to block

sputtered contaminants emanating from the end portion of the ionization region

from impinging the substrate.

37. The shielding system of claim 25 wherein the sputtered contaminants

are sputtered from a surface of the ion source.

38. The shielding system of claim 25 wherein the ion source has an

emission face from which the ion beam is emitted toward the substrate location

and the emission face is parallel to a surface of the substrate.

39. The shielding system of claim 25 wherein the ion source has an

emission face from which the ion beam is emitted in a normal direction from

the emission face toward the substrate location and the emission face is parallel

to a surface of the substrate.

40. The shielding system of claim 25 wherein the ion source has an

emission face from which the ion beam is emitted in a non-normal direction

from the emission face toward the substrate, location and the emission face is

parallel to a surface of the substrate.

41. The shielding system of claim 25 wherein the ion source has an

emission face from which the ion beam is emitted toward the substrate location

and the emission face is not parallel to a surface of the substrate.

42. The shielding system of claim 25 wherein the ion source has an

emission face from which the ion beam is emitted in a normal direction to the

emission face toward the substrate location and the emission face is not parallel

to a surface of the substrate.

43. The shielding system of claim 25 wherein the ion source has an

emission face from which the ion beam is emitted in a non-normal direction to

the emission face toward the substrate location and the emission face is not

parallel to a surface of the substrate.

44. The shielding system of claim 25 wherein the shielding system is

actively biased.

45. The shielding system of claim 25 wherein the shielding system is

actively biased to a positive potential.

46. The shielding system of claim 25 wherein the shielding system is

electrically isolated from the ion source.

47. The shielding system of claim 25 wherein the shielding system

comprises a process-compatible material.

48. The shielding system of claim 25 wherein the shielding system

comprises a contaminant-trapping material.

49. A method of processing a substrate, the method comprising: generating an ion beam and sputtering ions from a surface of an ion

source, the ion beam defining an envelope; positioning the substrate within the envelope; emitting sputtered contaminants sputtered from the surface of the ion

source by the sputtering ions; and blocking the sputtered contaminants emanating from the ion source from

impinging the substrate outside of the envelope of the ion beam.

50. The method of claim 49 wherein the surface is on a cathode of the

ion source.

51 . The method of claim 49 wherein the surface is on an anode of the ion

source.

52. The method of claim 49 wherein positioning the substrate within the

envelope comprises: passing the substrate through the envelope.

53. The method of claim 49 wherein the ion source has an emission face

from which the ion beam is emitted toward the substrate and the emission face

is parallel to a surface of the substrate.

54. The method of claim 49 wherein the ion source has an emission face

from which the ion beam is emitted in a normal direction from the emission face toward the substrate and the emission face is parallel to a surface of the

substrate.

55. The method of claim 49 wherein the ion source has an emission face

from which the ion beam is emitted in a non-normal direction from the

emission face toward the substrate and the emission face is parallel to a surface

of the substrate.

56. The method of claim 49 wherein the ion source has an emission face

from which the ion beam is emitted toward the substrate and the emission face

is not parallel to a surface of the substrate.

57. The method of claim 49 wherein the ion source has an emission face

from which the ion beam is emitted in a normal direction to the emission face

toward the substrate and the emission face is not parallel to a surface of the

substrate.

58. The method of claim 49 wherein the ion source has an emission face

from which the ion beam is emitted in a non-normal direction to the emission

face toward the substrate and the emission face is not parallel to a surface of

the substrate.

59. The method of claim 49 further comprising: actively biasing a shield blocking the sputtered contaminants.

60. The method of claim 49 further comprising: actively biasing a shield to a positive potential, the shield blocking the

sputtered contaminants.

61. The method of claim 49 further comprising: electrically isolating a shield from the ion source, wherein the shield

blocks the sputtered contaminants.

62. An ion source system comprising: an ion source capable of emitting an ion beam; and means for passing the ion beam from the ion source to impinge a

substrate while blocking sputtered contaminants from impinging the substrate.

63. The ion source system of claim 62 wherein the means for passing the

ion beam is positioned between the ion source and a substrate location defined

for passing the substrate through the ion beam.

64. The ion source system of claim 62 wherein the ion source includes a

cathode and the sputtered contaminants are sputtered from the cathode.

65. The ion source system of claim 62 wherein the ion source includes

an anode and the sputtered contaminants are sputtered from the anode.

66. The ion source system of claim 62 wherein the means for passing is

actively biased.

67. The ion source system of claim 62 wherein the means for passing is

actively biased to a positive potential.

68. The ion source system of claim 62 wherein the means for passing is

electrically isolated from the ion source.

69. The ion source system of claim 62 wherein the means for passing

comprises a process-compatible material.

70. The ion source system of claim 62 wherein the means for passing

comprises a contaminant-trapping material.