JP2009081032A - Ion implantation cluster tool using ribbon form beam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the apparatus cost and improve the productivity in an apparatus for implanting many kinds of ion onto a single wafer. <P>SOLUTION: Multiple ion beam line assemblies are arranged around a common processing chamber. Each of multiple ion beam line assemblies is selectively separated from the common processing chamber, and multiple ion beam lines intersects with each other at a processing region of the common processing chamber. A scanning apparatus arranged within the common processing chamber can be operated so that a workpiece holder gets across each of multiple ion beam lines to selectively move in one or more directions in the processing region. A common dose measuring apparatus arranged within the common processing chamber can be operated to measure one or more characteristics in each of multiple ion beam lines. To exchange a workpiece between the common processing chamber and an external environment, a load lock chamber is linked to the common processing chamber operatively. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates generally to ion implantation systems and methods for ion implantation into a workpiece, and more particularly to systems having multiple ion beam line assemblies coupled to a common processing chamber.

  In the manufacture of semiconductor devices, ion implanters are used to dope semiconductors with impurities. In such a system, a desired dopant element is ionized in the ion source and the dopant element is extracted from the ion source in the form of an ion beam. The ion beam is typically directed to the surface of the semiconductor for implanting a dopant element into the wafer after ions having the desired charge to mass ratio are selected by mass spectrometry. The ions of the beam penetrate the surface of the wafer, forming a region having the desired conductivity, for example, when manufacturing transistor devices in the wafer. A typical ion implanter includes an ion source that generates an ion beam, a beam line assembly that includes a mass analyzer for resolving the ion beam by mass using a magnetic field, and a semiconductor wafer implanted by the ion beam. Or a target chamber containing a workpiece.

  Typically, ions generated from an ion source are shaped into a beam and directed along a predetermined beam path to an implantation station. The ion beam implanter may further include a beam forming / shaping structure that extends between the ion source and the implantation station. The beam shaping / shaping structure maintains the ion beam and forms an elongated internal cavity or path through which the beam passes on its way to the implantation station. During operation of the ion implanter, this passage is typically evacuated to reduce the probability that ions will deviate from the predetermined beam path as a result of collisions with air molecules.

  The mass of an ion relative to its charge (ie, charge-to-mass ratio) affects the degree to which the ion is accelerated in both the axial and lateral directions by an electrostatic or magnetic field. Therefore, by deflecting ions of unnecessary molecular weight away from the beam, the purity of the beam reaching the desired region of the semiconductor wafer or other target is greatly improved, and implantation of materials other than the desired material is performed. It can be avoided. This process of separating ions having a desired charge to mass ratio from ions that are not is known as mass spectrometry. Mass spectrometry typically uses a mass analyzing magnet to generate a dipole magnetic field and deflects various ions in the ion beam by magnetic deflection in an arcuate path, thereby varying the charge-to-mass ratio. It effectively separates the ions it has.

  The ion beam is focused and guided to the desired surface area of the workpiece in the target station. The high energy ions of the ion beam are accelerated to a predetermined energy level that penetrates into the workpiece. For example, ions are embedded in the crystal lattice of the material to form a region having the desired conductivity, where the depth of implantation is largely determined by the energy of the ion beam. The ion beam may be a spot beam (eg, a pencil beam), in which case the workpiece is mechanically scanned in a two-dimensional direction orthogonal to the substantially stationary spot beam. The ion beam may also be a ribbon beam, in which case the beam is electromagnetically scanned in one direction on the workpiece while the workpiece is mechanically scanned in the orthogonal direction. The ion beam may be an electromagnetic scanning beam that is electromagnetically scanned in a two-dimensional direction on a stationary workpiece. Examples of ion implantation systems include ion implantation systems commercially available from Axcelis Technologies of Beverly, Massachusetts, USA.

  Conventionally, typical ion implantation systems include a processing chamber, and the workpiece is placed on a workpiece holder in the processing chamber during implantation. The processing chamber typically maintains a processing environment that is isolated from the other environment, and there is usually limited cross-contamination from the processing environment to the other environment. In an ion implantation system that uses mechanical scanning of a workpiece, the workpiece holder is typically coupled to a scanning device in the processing chamber, and the scanning device moves the workpiece holder relative to the ion beam. It is operable to move in one or more directions. In addition, a beam monitoring device (eg, a Faraday cup) is typically provided in the processing chamber in line with the ion beam for processing feedback.

  There are also processing methods that use a cluster tool to perform several different processes on a single wafer, in which case the workpiece is transferred between various processing environments within the cluster tool. For example, the conventional cluster tool 10 shown in FIG. 1 is configured to execute various processes on the workpiece 15. The cluster tool 10 includes, for example, a first ion implantation apparatus 20, a second ion implantation apparatus 25, an etching station 30, a resist asher 35, and a load lock chamber 49 that surround a central workpiece transfer station 45. The first ion implanter 20, the second ion implanter 24, the etching station 30, the resist asher 35, and the load lock chamber 49 are inherently separated from the workpiece transfer station 45 by respective gate valves 55A-55D. Each of the processing chambers has an independent processing environment 60A-60D for processing the workpiece 15. Further, each processing chamber 50A-50D includes a unique workpiece holder 65A-65D, and in the case of the first ion implanter 20 and the second ion implanter 25, the workpiece holders 65A, 65B are further respectively Coupled to the corresponding first scanning device 70A and second scanning device 70B. Further, in the case of the first ion implantation apparatus 20 and the second ion implantation apparatus 25, the corresponding first beam monitoring apparatus 75A and second beam monitoring apparatus 75B are disposed in the respective processing chambers 50A and 50B. The first ion beam line 80A and the second ion beam line 80B corresponding to each ion implantation apparatus are monitored.

  During operation, the workpiece is typically transferred between the plurality of processing chambers 50A-50D by the workpiece handler 80 based on the desired processing on the workpiece. For example, when it is desired to implant a plurality of different ion species into the workpiece 15, the first ion beam line 85A and the second ion beam line 85B respectively corresponding to the first ion implanter 20 and the second ion implanter 25 are provided. , Configured to have different ion species associated with each ion beam line. Then, the workpiece 15 is transferred from the load lock chamber 40 to the first processing chamber 50A through the gate valve 55A, and is disposed on the workpiece holder 65A coupled to the first scanning device 70A in the processing chamber 50A. Next, the gate valve 55A is closed, the first processing chamber 50A is evacuated, and the workpiece 15 is scanned across the first beam line 85A by the first scanning device 70A. The first beam line is monitored by a first beam line monitoring device 75A in the processing chamber 50A.

  When the desired ion implantation by the first ion implantation apparatus 20 is completed, the gate valve 55A is opened, and the workpiece 15 is taken out from the processing chamber 50A of the first ion implantation apparatus and returned to the transfer station 45. Next, the workpiece 15 is transferred into the processing chamber 50B of the second ion implantation apparatus 25 through the gate valve 55B, and on the workpiece holder 65B coupled to the second scanning device 70B in the processing chamber 50B of the second ion implantation apparatus. Placed in. Next, the gate valve 55B is closed and the processing chamber 50B is evacuated. Thereafter, the workpiece 15 is scanned by the second scanning device 70B through the second beam line 85B of the second ion implantation device 25. Here, the second beam line is monitored by the second beam line monitoring device 75B in the processing chamber 50B. When the desired ion implantation by the second ion implantation apparatus 25 is completed, the gate valve 55B is opened, and the workpiece 15 is taken out from the processing chamber 50B of the second ion implantation apparatus and returned to the transfer station 45. Here, depending on the case, another process is executed.

  However, in the conventional cluster tool as described above, each ion implantation apparatus 20, 25 has its own processing chamber 50A, 50B, scanning apparatus 70A, 70B, beam monitoring apparatus 75A, 75B, and typically Since it has a controller (not shown) for controlling the ion implantation system, it is expensive. Thus, an improved ion implantation system that allows increased efficiency by sharing common components among multiple ion beam lines, thereby reducing the cost of ownership associated with having multiple beam lines There is a desire to provide cluster tools.

  The present invention provides an ion implantation cluster tool in which multiple ion beam lines share components such as a common processing chamber, a scanning device, a beam monitoring device, a workpiece handling device, and a controller. It overcomes the limitations. A brief summary of the invention will now be presented to provide a basic understanding of some aspects of the invention. However, this summary is not an overview of the entire invention. Also, this summary does not identify items or essential elements that specify the invention, nor does it define the scope of the invention. The purpose of this summary is to briefly present some concepts of the invention as an introduction to the detailed description that is presented later.

  The present invention relates to an ion implantation cluster tool for implanting ions into a workpiece. In accordance with one aspect of the present invention, a plurality of ion beam line assemblies having each of a plurality of ion beam lines are disposed around a common processing chamber. The common processing chamber is operable, for example, to be evacuated by one or more vacuum pumps. For example, each of the plurality of ion beam line assemblies is further selectively separated from the common processing chamber by one or more gate valves, thereby selectively separating from the vacuum environment within the common processing chamber.

  In accordance with an exemplary aspect of the present invention, a plurality of ion beam lines associated with a plurality of ion beam line assemblies intersect at a processing region of a common processing chamber. A scanning device is disposed within the common processing chamber, wherein the workpiece holder that holds the workpiece is selectively in the processing region in one or more directions across each of the plurality of ion beam lines. It is operable to move to. For example, the scanning device may include a robot having three or more degrees of freedom. A two-dimensional scanning system may also be coupled to the scanning device, the two-dimensional scanning system being operable to perform a predetermined scan of the workpiece across the selected ion beam line. Is.

In accordance with another exemplary aspect of the present invention, a common dosimetry device, such as Faraday, is disposed in a common processing chamber, the common dosimetry device comprising one or more of each of a plurality of ion beam lines. It is operable to measure characteristics. The common dosimetry device may be operably coupled to the scanning device, for example. Furthermore, a load lock chamber operably coupled to the common processing chamber may be provided, and the workpiece may be exchanged between the common processing chamber and the external environment by a common workpiece handling device.
As described above, the present invention includes a processing chamber, a scanning device, a dose measuring device, and a workpiece handling device that are common to a plurality of ion beam lines. Provides cluster tools.

  To the accomplishment of the above and related ends, the invention is described in detail below and includes the features specifically set forth in the appended claims. The accompanying drawings and the description of the drawings set forth in detail certain illustrative aspects and embodiments of the invention, which are just a few of the various aspects in which the principles of the invention may be used. Is. Other aspects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.

  The present invention generally relates to a system for efficiently supplying a plurality of ion beam lines to a common processing chamber. Hereinafter, the present invention will be described with reference to the drawings. In the following description, like elements are referred to with the same reference numerals. In addition, the description of each aspect is merely exemplary and should not be construed in a limiting sense. In the following description, for purposes 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 one skilled in the art that the present invention may be practiced without the use of these specific details.

  FIG. 2 shows a top view of an exemplary ion implantation cluster tool 100 in accordance with the present invention. The ion implantation cluster tool 100 includes a common processing chamber 102 to which a plurality of ion beam line assemblies 104A-104C are operatively coupled. Although three ion beam assemblies 104A-104C are shown in FIG. 2, any number of ion beam assemblies 104 greater than one can be coupled to this common processing chamber. Any number of such ion beam assemblies are within the scope of the present invention. Each ion beam assembly 104 includes, for example, an ion source 106, an extraction assembly 108 (eg, an extraction electrode or extraction optics), a mass analysis magnet 110, and an exit or mass resolving aperture 112, each with a different ion beam 114A. -114C (e.g., beamline) operable to generate. Each beamline assembly 104A-104C may further include, for example, a tuning Faraday 115A-115C, which tunes a respective beamline 114A-114C upstream of the common processing chamber 102. The beam lines 114A-114C generated by each ion beam line assembly 104A-104C are scanned electromagnetically or electrostatically by a stretched ribbon beam, spot or pencil beam, or the respective beam line assembly. The scanning beam may have a cross-sectional shape. Each beamline assembly 104 </ b> A- 104 </ b> C may have, for example, a different ionic species, so that various different doping processes can be performed by the cluster tool 100.

  The plurality of ion beam assemblies 104 can be configured to provide any combination of one or more of the beamline shapes and ion species described above. For example, the beamline assemblies 104A, 104B are configured to generate a ribbon beam consisting of a single ion species, while the beamline assembly 104C is configured with a scanning pencil beam consisting of different ion species. You may comprise so that it may generate | occur | produce. As described above, the present invention is not limited by the shape of the ion beam generated by the plurality of beam line assemblies 104, and any beam line shape or a scanning method of the beam line is included in the scope of the present invention. is there. Regardless of the shape or configuration of the plurality of beam lines 114A-114C, each beam line traverses the processing region 116 of the common processing chamber, details of which will be described later.

  The common processing chamber 102 in the present invention includes a central vacuum chamber 118 in fluid communication with, for example, one or more vacuum pumps 120A-120B (eg, cryogenic pumps), and the one or more vacuum pumps include the central vacuum chamber. The inside is substantially evacuated. The ion implantation cluster tool 100 may further include a load lock chamber 122 operatively connected to the common processing chamber 102 via one or more divider valves 124, and the internal environment 126 of the load lock chamber is: It is operable to selectively communicate with the vacuum environment 128 within the common processing chamber. As will be described below, the load lock chamber 122 is, for example, for transferring one or more workpieces 130 (eg, semiconductor substrates or wafers) from outside to inside of the common processing chamber 102 or from inside to outside. Can be used.

  In accordance with one exemplary aspect of the present invention, the ion implantation cluster tool 100 may further include a scanning device 132. The scanning device is disposed within the common processing chamber 102 and is operable to hold a workpiece and move it in one or more directions. For example, the scanning device 132 includes a workpiece holder 134 (eg, an electrostatic chuck) for holding the workpiece 130, and the workpiece holder (and thus the workpiece) is in the processing region 116 of the common processing chamber 102. It is operable to selectively move in one or more directions across the plurality of ion beam lines 114A-114C.

  In the example shown in FIG. 2, the workpiece holder 134 is shown moving between a first position 136A and a second position 136B relative to the beamline 114C. However, the incident angle (eg, “tilt angle”) formed between each of the plurality of beamlines 114A-114C and the workpiece 130 can be selected for each beamline, and the scanning device 132 is And, further, operable to maintain a constant focus scan of the workpiece for each beamline. An example of a scanning device 132 is described in US Pat. No. 6,900,444, issued to Axcelis Technologies, Inc. of Beverly, Mass., The contents of which are incorporated herein by reference.

  For example, the scanning device 132 is further operable to move the workpiece 130 between the processing region 116 in the common processing chamber 102 and the load lock chamber 122. The scanning device 132 may include a central robot 138 having at least three degrees of freedom. The scanning device 132 may also include a two-dimensional scanning system 140 in which the workpiece holder 134 is substantially orthogonal with respect to each of the plurality of ion beam lines 114A-114C. It is operable to move in the processing area 116 in the axial direction. For example, the central robot 138 is operable to position the workpiece holder 134 such that the workpiece 130 is substantially orthogonal to each beamline 114A-114C, and the two-dimensional scanning system 140 further includes: The workpiece holder is operable to move along two substantially orthogonal axes with respect to each beam line. This realizes a two-dimensional scan of the workpiece across each beam line. In another example, the central robot 138 not only scans the workpiece holder 134 (and hence the workpiece 130) across each beamline 114A-114C along two substantially orthogonal axes, but also loads It is operable to move the workpiece 130 between the lock chamber 122 and the processing region 116.

  In accordance with another exemplary aspect of the present invention, the ion implantation cluster tool 100 includes a (common) dosimetry device 142 associated with a common processing chamber 102 that includes a plurality of ion beam lines 114A-. 114C is operable to measure one or more characteristics (eg, beam current) of each. The dosimetry device 142 may include, for example, a Faraday cup 143A-143C associated with each of the beamlines 114A-114C, and each Faraday cup is operably coupled to the common processing chamber 102. The dosimetry device 142 may also include a Faraday cup 144 operably coupled to the scanning device 132, which further includes a dosimetry device across the plurality of beamlines 114A-114C. Is operable to move selectively.

  In accordance with another exemplary aspect of the present invention, the ion implantation cluster tool 100 includes a workpiece handling device 146 operably coupled to a common processing chamber 102. The workpiece handling device is configured to transfer the workpiece between the workpiece holder 134 of the scanning device 132 and the load lock chamber 122. The workpiece handling device 146 may be incorporated, for example, in the scanning device 132 (eg, the central robot 136) or to transfer the workpiece 130 between the workpiece holder 134 and the load lock chamber 122. It may be another robot or a moving mechanism (not shown) coupled to the scanning device 132 that is operable.

  As described above, the ion implantation cluster tool 100 according to the present invention advantageously includes a plurality of ion implantation cluster tools 100 disposed around the common processing chamber 102 such that the respective beamlines 114A-114C intersect at the processing region 116. Beam line assemblies 104A-104C, and workpiece 130 is ion implanted by each beam line. For example, the plurality of beam lines 114A-114C intersect each other at the target position 148 in the processing region 116. In this case, the target position is set so that the workpiece 130 is substantially orthogonal to each beam line. Can be arranged. This provides efficiency that was not previously available. For example, the scanning device 132 is shared by all beamline assemblies 104A-104C, and the common scanning device 132 properly positions the workpiece holder 134 for implantation by each beamline 114A-114C. be able to. Further, the dose measuring device 142 is shared by all the beam line assemblies 104A-104C, and the common dose scanning device 142 is appropriately arranged by the scanning device 132, so that all the beam line assemblies 104A are arranged. It is operable to be able to show the characteristics of -104C. Still further, the common controller 148 may be configured to control the ion implantation cluster tool 100 by controlling the beamline assemblies 104A-104C and the scanning device 132. A common controller 148 may implement feedback control through the dosimetry device 142 to control each beamline assembly 104A-104C, and may further control the scanning device 132 (eg, a common processing chamber). The operation of the workpiece 130 may be controlled through the control of a central robot 136 that transfers the workpiece between the vacuum environment 128 in the 102 and the load lock chamber 122.

  Another efficiency provided by the present invention is that two or more beamline assemblies (eg, beamline assemblies 104A, 104B) can be configured to provide the same type of ion beam having the same ion species. In addition, the beam line assembly is made redundant. Thus, if one of the beamline assemblies (eg, beamline assembly 104A) fails or requires maintenance, the other surplus beamline assembly (eg, beamline assembly 104B) is ready. Can be used for injection, and processing interruption time can be reduced.

  In accordance with another exemplary aspect of the present invention, the plurality of beamline assemblies 104A-104C each include a gate valve 150A-150C. This gate valve selectively separates the plurality of beam line assemblies from the common processing chamber 102. For example, if the ion species associated with the beamline assembly 104C is desired, the gate valve 150C is opened and the gate valves 150A, 150B are closed so that the beamline assemblies 104A, 104B are placed in the vacuum environment 128 of the common processing chamber 102. Is substantially separated from This makes it possible to perform maintenance work on the beam line assemblies 104A and 104B, for example, while continuing ion implantation into the workpiece 130 by the beam line assembly 104C. In addition, the gate valves 150A-150C form an environmental protection wall between the beam line assemblies 104A-104C, thereby minimizing cross-contamination between the beam line assemblies.

  Thus, the present invention provides an efficient ion implantation cluster tool 100 that reduces the cost of ownership and increases productivity by using common components compared to conventional systems. And the efficiency is advantageously improved.

  While the invention has been illustrated and described in connection with specific aspects and embodiments, those skilled in the art will be able to conceive equivalent changes and modifications based on an understanding of this specification and the accompanying drawings. Will be understood. In particular, with respect to the various functions performed by the components described above (assemblies, apparatus, devices, circuits, systems, etc.), terms used to describe such components (including references to “means”) Unless otherwise stated, any configuration that performs that function (ie, is functionally equivalent) of the above-described components that perform the specified function in the exemplary embodiments of the invention shown herein. An element is equivalent even if it is not structurally equivalent to the disclosed configuration. In addition, even if certain features of the present invention are disclosed in connection with only one of several aspects, it may be desirable and advantageous for a given or specific application, Such features can also be combined with one or more features of other aspects.

FIG. 1 is a plan view of a conventional cluster tool for processing a workpiece according to the prior art. FIG. 2 is a diagram illustrating an example of an ion implantation cluster tool in accordance with an aspect of the present invention.

Claims (20)

A plurality of ion beam line assemblies each having a plurality of ion beam lines;
A common processing chamber in which each of the plurality of ion beam lines intersects in a processing region;
Located within the common processing chamber and including a workpiece holder, the workpiece holder is operable to selectively move in the processing region in one or more directions across the plurality of ion beam lines. A scanning device,
A dosimeter associated with the common processing chamber and operable to measure one or more characteristics of each of the plurality of ion beam lines;
A load lock chamber operably coupled to the common processing chamber;
An ion implantation cluster tool characterized by comprising:   The workpiece handling apparatus, further comprising a workpiece handling device, wherein the workpiece handling device is configured to transfer a workpiece between the workpiece holder and the load lock chamber, the majority of the workpiece being in the common processing chamber. 2. The ion implantation cluster tool according to 1.   The plurality of ion beam line assemblies are disposed around the common processing chamber, and the plurality of ion beam lines intersect each other at a target position in the processing region. Ion implantation cluster tool.   The common processing chamber is operably coupled to one or more vacuum pumps, and the one or more vacuum pumps are operable to create a substantially evacuated environment within the common processing chamber. The ion implantation cluster tool according to claim 1.   Each of the plurality of ion beam line assemblies further includes a plurality of gate valves respectively associated with the plurality of ion beam line assemblies, wherein the plurality of gate valves are configured to selectively transmit each of the plurality of ion beam line assemblies from the common processing chamber. The ion implantation cluster tool of claim 1, wherein the ion implantation cluster tool is operable to separate.   The ion implantation cluster tool according to claim 1, wherein the scanning device includes a robot having at least three degrees of freedom.   The scanning apparatus includes a two-dimensional scanning system operable to move the workpiece holder in the processing region in two substantially perpendicular directions with respect to each of the plurality of ion beam lines. The ion implantation cluster tool according to claim 1.   The dosimetry apparatus includes a Faraday cup associated with each of the plurality of ion beam line assemblies, each Faraday cup being operably coupled to the common processing chamber. 2. The ion implantation cluster tool according to 1.   The dosimetry device is operatively coupled to the scanning device, the scanning device selectively moving the dosimetry device across the plurality of ion beam lines. Item 12. The ion implantation cluster tool according to Item 1.   The ion implantation cluster tool of claim 1, wherein each of the plurality of ion beam line assemblies includes an ion source, an extraction assembly, a mass spectrometer, a mass resolving aperture, and a conditioning Faraday.   The ion implantation cluster tool of claim 1, wherein one or more of the plurality of ion beam line assemblies are configured to form a ribbon ion beam.   The ion implantation cluster tool of claim 1, wherein each of the plurality of ion beam line assemblies includes an adjustment Faraday disposed upstream of the common processing chamber.   The ion implantation cluster tool according to claim 1, wherein each of the plurality of ion beam line assemblies has a different ion species. A common processing chamber;
A load lock chamber operably coupled to the common processing chamber;
A plurality of ion beam lines disposed around the common processing chamber and operably coupled to the common processing chamber and configured to supply each of a plurality of ion beam lines directed toward a processing region of the common processing chamber. Ion beam line ensemble,
Mostly disposed within the common processing chamber and including a workpiece holder operable to hold a workpiece and operable to move the workpiece across each of the plurality of ion beam lines. And a workpiece handling device operable to perform movement of the workpiece between the common processing chamber and the load lock chamber;
A common dosimetry device associated with the workpiece handling device and operable to measure one or more characteristics of each of the plurality of ion beam lines;
A controller configured to control each of the plurality of ion beam line assemblies;
An ion implantation system comprising:   The ion implantation system according to claim 14, wherein each of the plurality of ion beam lines intersects at a processing region of the common processing chamber.   15. The controller of claim 14, wherein the controller is further operable to control the plurality of ion beam line assemblies based on one or more characteristics measured by the common dosimetry device. Ion implantation system.   The common dosimetry device includes a Faraday cup associated with each of the plurality of ion beam line assemblies, each of the Faraday cups being operably coupled to the common processing chamber. Item 15. The ion implantation system according to Item 14.   15. The gate valve of claim 14, further comprising a plurality of gate valves associated with each of the plurality of ion beam lines to selectively separate each of the plurality of ion beam line assemblies from the common processing chamber. Ion implantation system.   15. The ion implantation system according to claim 14, wherein one or more of the plurality of ion beam line assemblies comprises an ion implantation apparatus using a ribbon beam. The ion implantation system of claim 14, wherein each of the plurality of ion beam line assemblies includes a tuning Faraday disposed upstream of the common processing chamber.

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