Dual source injector with switchable analytical magnet

Abstract

The ion implantation system includes a mass analysis magnet. The mass analysis magnet has an interior region and an exterior region and defines a first entrance, a second entrance, and an exit. The first ion source defines a first ion beam along a first beam path toward the first entrance. The second ion source defines a second ion beam along a second beam path toward the second entrance. A magnet current source provides magnet current to the mass analysis magnet. A magnet control circuit controls a polarity of the magnet current based on the formation of the first ion beam or the second ion beam. The mass analysis magnet mass analyzes the first ion beam or the second ion beam, respectively, and defines a post-mass analysis ion beam along the mass analysis beam path. At least one shield located in the interior region or the exterior region blocks a line of sight between the first ion source and the second ion source. A beamline component modifies the post-mass analysis ion beam.

Description

Detailed Description of the Invention

[0001] [Field] FIELD OF THEINVENTION The present invention relates generally to ion implantation systems and methods, and more particularly to mass analysis magnets configured with multiple ion sources.

[0002] [background] Ion implanters are traditionally utilized to place a predetermined amount of dopants or impurities within a workpiece or semiconductor wafer. In a typical ion implantation system, a dopant material is ionized to generate a beam of ions (commonly referred to as an ion beam). To implant ions within the workpiece, the ion beam is directed at a surface of the workpiece. The ions penetrate the surface of the workpiece and form a region of a desired conductivity within the workpiece. For example, ion implantation is particularly used in the manufacture of transistors in semiconductor workpieces. A typical ion implanter includes (i) an injector, (ii) a beamline assembly having a mass analyzer for directing and / or filtering (e.g., mass resolving) ions within the ion beam, and (iii) a process chamber containing one or more workpieces to be processed.

[0003] Typically, an ion source associated with the injector generates ions. Ions are extracted from the ion source to form an ion beam. A desired ion species is selected for implantation by an analyzing magnet. A beamline further modifies the ion beam to define a final ion beam. Such modifications include ion beam acceleration, deceleration, scanning, and / or angle control. Typically, a process chamber receives the final ion beam for implantation into a workpiece.

[0004] Conventional injectors often suffer from so-called "ion source lifetime" problems, which are related to cathode erosion, material deposition inside the ion source, as well as the associated flaking and electrical glitching. Such ion source lifetime problems result in a shortened ion source lifespan, which requires ion source maintenance and / or replacement. Thus, the productivity of the ion implanter is adversely affected.

[0005] Some ion implanters implement multiple ion sources to allow for changing from a first ion species to a second ion species, or to change ion sources when maintenance is required for each ion source. However, such conventional ion sources typically require all ion sources in the ion implanter to be shut down for removal or maintenance of an ion source, as the ion sources emit harmful x-ray radiation during operation. Thus, the productivity of the implanter is reduced for ion source maintenance or source species switching.

[0006] [overview] The present disclosure provides an ion implantation system having multiple ion sources, which allows safe and easy access to each ion source while maintaining operation of the ion implantation system. The following presents a simplified summary of the disclosure in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key elements of the invention or to delineate the scope of the invention. Its purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.

[0007] In accordance with the present disclosure, an ion implantation system is provided that includes a mass analysis magnet that includes a yoke and a coil that define a first entrance, a second entrance, and an exit of the mass analysis magnet, where one or more of the yoke and the coil define, for example, an interior region and an exterior region of the mass analysis magnet.

[0008] According to an exemplary embodiment, the first ion source is configured to define a first ion beam along a first beam path toward a first entrance of the mass analysis magnet, the second ion source is configured to define a second ion beam along a second beam path toward a second entrance of the mass analysis magnet, and the magnet current source is configured to provide magnet current to the mass analysis magnet.

[0009] As an example, the magnet control circuit is connected to the mass analysis magnet and the magnet current source. The magnet control circuit is configured to selectively control the polarity of the magnet current supplied to the mass analysis magnet based on the selective formation of the first ion beam and the second ion beam, respectively. For example, the mass analysis magnet is configured to mass analyze the first ion beam and the second ion beam, respectively. In this case, a mass analyzed ion beam is defined at the exit of the mass analysis magnet along the mass analysis beam path. The beamline components are further disposed, for example, downstream of the mass analysis magnet and configured to direct the mass analyzed ion beam toward the workpiece. The beamline components may include, for example, one or more of an accelerator, a decelerator, an energy filter, a focusing lens, a steering lens, a measurement system, a scanner, and a calibrator.

[0010] According to another exemplary embodiment, one or more shields are disposed in one or more of the interior and exterior regions of the mass analysis magnet. The one or more shields are configured, for example, to block a line-of-sight between the first ion source and the second ion source. The one or more shields may be configured to generally prevent transmission of x-rays between the first ion source and the second ion source. For example, at least one of the one or more shields is constructed of lead.

[0011] For example, the one or more shields can include a central shield disposed in an interior region of the mass analysis magnet between a first entrance and a second entrance of the mass analysis magnet. For example, the mass analysis beam path defines an exit axis. The central shield is disposed along the exit axis.

[0012] In another example, the one or more shields include one or more external magnet shields disposed in an exterior region of the mass analysis magnet, where the one or more external magnet shields extend generally perpendicular to the exit axis. The one or more exterior shields may be disposed, for example, parallel to the exit axis. The one or more exterior shields may have an exit aperture, for example, defined along the mass analysis beam path.

[0013] In another example, the first beam path defines a first entrance axis and the second beam path defines a second entrance axis. Thus, the one or more shields may further include a first entrance shield and a second entrance shield disposed along the first entrance axis and the second entrance axis, respectively. The first entrance shield and the second entrance shield may be disposed, for example, in an interior region of the mass analysis magnet.

[0014] In another example, the mass analysis magnet includes a dipole magnet, where a uniform magnetic field having substantially flat poles is defined within the dipole magnet, and the dipole magnet is configured to deflect the first and second ion beams, for example, in a range of deflection angles from about 70° to about 110° as viewed along the first and second beam paths, respectively.

[0015] According to another aspect of the present disclosure, a method for maintaining an ion implantation system is provided. In one example, the method includes applying a polarity of magnet current to a mass analysis magnet, where one or more shields are provided inside the mass analysis magnet. A first ion source current is applied to a first ion source to form a first ion beam, and the first ion beam is directed along a first beam path toward a first entrance of the mass analysis magnet. The first ion beam is then mass analyzed. In this case, the first ion beam is deflected at an angle of about 70° to about 110°. Furthermore, the first ion source current applied to the first ion source is stopped, whereby the first ion beam can be extinguished.

[0016] For example, the polarity of the magnet current applied to the mass analysis magnet is reversed, and a second source current is applied to the second ion source, resulting in the formation of a second ion beam that is directed along a second beam path toward a second entrance of the mass analysis magnet, where the second ion beam is mass analyzed and deflected at an angle of about 70° to about 110°.

[0017] Thus, while forming the second ion beam, maintenance may be performed on the first ion source, with the line of sight between the first and second ion sources being blocked by one or more shields located within the mass analysis magnet, which generally prevents x-ray emissions from the second ion source from reaching the first ion source.

[0018] To the accomplishment of the foregoing and related ends, the invention comprises the structure hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings disclose in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of some of the various ways in which the principles of the invention may be employed. Other objects, 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.

[0019] [Brief description of the drawings] 1A-1B are schematic diagrams illustrating an example of an ion implantation system having multiple ion sources and a single beam line according to various embodiments of the present invention.

[0020] FIG. 2 is a schematic perspective view of an exemplary mass analysis magnet according to various embodiments of the present invention.

[0021] FIG. 3A is a schematic diagram of an exemplary mass analyzing magnet having a first polarity applied to a coil according to various embodiments of the present invention.

[0022] FIG. 3B is a schematic diagram of the exemplary mass analysis magnet of FIG. 3A with a second polarity applied to the coils according to various embodiments of the present invention.

[0023] FIG. 4 is a plan view in partial cross section of an exemplary mass analyzing magnet according to various embodiments of the present invention.

[0024] FIG. 5 is a plan view in partial cross section of an exemplary mass analysis magnet having shielding according to various embodiments of the present invention.

[0025] FIG. 6 is a plan view in partial cross section of an exemplary mass analyzing magnet having multiple shields according to various embodiments of the present invention.

[0026] FIG. 7 illustrates an exemplary method for implanting ions into a workpiece according to various further aspects of the present invention.

[0027] [Detailed Description] The present disclosure is generally directed to an ion implantation system and method for implanting ions into a workpiece. A mass analysis magnet is configured to receive ions generated from a plurality of ion sources. A shielding arrangement is provided, such that, for example, each of the plurality of ion sources may be safely and individually accessed and maintained during operation of any other of the plurality of ion sources in the system. The present invention will now be described with reference to the drawings. Like reference numerals may be used to refer to like elements throughout. It should be understood that the description of these aspects is merely exemplary and should not be taken 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 these specific details.

[0028] In accordance with various aspects of the present disclosure, an ion implantation system is provided having an injector including multiple ion sources, which can increase the productivity of the ion implantation system. For example, a pair of ion sources may be configured to generate ions from different source materials, which can avoid memory effects when changing between implants using different source feed materials. Additionally, the present disclosure advantageously allows for maintenance to be performed on a first ion source of a pair of ion sources while a second ion source of the pair is generating ions for an implant, thereby minimizing downtime compared to conventional systems.

[0029] The ion implantation system of the present disclosure utilizes multiple ion sources that can be individually maintained along with the operation of the ion implantation system. Thus, the present disclosure is particularly useful in applications that use radio frequency (RF) ion sources. RF ion sources can provide significantly longer life spans than traditional arc discharge ion sources. However, due to the memory effect and radiation concerns discussed above, RF ion sources have not been widely implemented for ion implantation due to the time and complexity of replacing or cleaning RF ion sources in conventional systems.

[0030] Generally, the multiple ion sources of the present disclosure can inject individual ion beams into separate entrances of, for example, a dual polarity analyzing magnet, where a mass analyzed ion beam is generated at the exit of the analyzing magnet, and a common beamline component transports the mass analyzed ion beam downstream of the analyzing magnet to a common process chamber, thus significantly reducing the cost and complexity associated with conventional implanters employing two beamlines and a common process chamber.

[0031] Referring now to the drawings, FIGS. 1A-1B illustrate an ion implantation system 100 (also referred to as an ion implanter) according to various aspects of the present disclosure. For example, as shown in FIG. 1A, the ion implantation system 100 includes a first ion source 102. The first ion source 102 is configured to generate a first ion beam 104 along a first beam path 106. The first ion source 102 includes, for example, a first arc chamber 108. In this case, a first source arc current 110 ionizes a first source material 112. The first ion beam 104 is then extracted from the first ion source using a first extraction device 114 (e.g., one or more electrodes biased relative to the first arc chamber 108).

[0032] For example, a second ion source 116 is also provided. The second ion source includes a second arc chamber 118. In this case, a second source arc current 120 ionizes a second source material 122. As shown in FIG. 1B, the second ion source is configured to generate a second ion beam 124 along a second beam path 126. For example, the second ion beam 124 is extracted from the second ion source using a second extraction device 128 (e.g., one or more electrodes biased relative to the second arc chamber 118).

[0033] For example, the ion implantation system 100 further includes a mass analysis magnet 130 configured to receive the first ion beam 104 of FIG. 1A and the second ion beam 124 of FIG. 1B. For example, FIG. 2 illustrates the mass analysis magnet 130. As described in more detail below, the mass analysis magnet 130 includes a magnetic field generating component configured to generate a dipole magnetic field within the mass analysis magnet. For example, the mass analysis magnet 130 includes a first entrance 132 and a second entrance 134 defined within the mass analysis magnet. In this case, the first entrance is configured to receive the first ion beam 104 from the first ion source 102 of FIG. 1A. The second entrance is configured to receive the second ion beam 124 from the second ion source 116 of FIG. 1B. Only ions having the correct mass-to-charge ratio can pass through the exit 136 of the mass analyzing magnet 130 and then be resolved by the mass resolving aperture 138 for passage downstream to various beamline components 140. Ions that do not have the correct charge-to-mass ratio will collide with the walls of the mass analyzing magnet 130 and / or the mass resolving aperture 138 and will not pass through the mass resolving aperture.

[0034] For example, magnet control circuitry 142 is further provided. Magnet control circuitry 142 is configured to supply magnet current 144 to coil 146 of mass analysis magnet 130. In this case, magnet current 144 to coil 146 cooperates with yoke 147 (e.g., steel laminations) as shown, for example, in FIG. 2. This results in a magnetic field B based on the strength and polarity of the magnet current, as can be seen in FIGS. 3A-3B.

[0035] For example, as shown in Figure 3A, the direction of the magnetic field B is given by Maxwell's corkscrew rule. As shown in Figure 3A, if the magnet current 144 flows counterclockwise (illustrated by the counterclockwise arrow), the magnetic field B points out of the plane of the page. The deflection of the first ion beam 104 (e.g., a positive ion beam) is given by Fleming's left-hand rule. Thus, the positive ions of the first ion beam 104, having a velocity v, experience a normal force F and are deflected as shown in Figure 3A.

[0036] 3B shows an example of a second ion beam 124 (e.g., a positive ion beam). In the example of FIG. 3B, the magnet current 144 flows in a clockwise direction (illustrated by the clockwise arrow). Thus, the mass analysis magnet 130 is configured to individually resolve each of the first ion beam 104 from the first ion source 102 and the second ion beam 124 from the second ion source 116 shown in FIG. 1A by simply switching the polarity of the magnet current 144. This allows a mass analyzed ion beam 148 to be defined at the exit 136 of the mass analysis magnet 130 along a mass analysis beam path 150.

[0037] A magnet control circuit 142 (e.g., a controller or other switching device) is operatively connected to, for example, the mass analysis magnet 130 and the magnet current source 151. In this case, the magnet control circuit is configured to selectively control the polarity of the magnet current 144 supplied to the mass analysis magnet based on the selective formation of the first ion beam 104 and the second ion beam 124, respectively. The mass analysis magnet is then configured to individually mass analyze the first ion beam and the second ion beam, respectively. For example, only one of the first ion source 102 and the second ion source 116 is operated at a time. In this case, as shown in Figures 3A and 3B, the polarity of the magnet current 144 is selectively controlled based on the desired operation of the first ion source or the second ion source.

[0038] For example, the mass analysis magnet 130 shown in Figures 1A-1B includes a dipole magnet 152 (e.g., a uniform magnetic field magnet having substantially flat poles). The dipole magnet 152 has a predetermined deflection angle 154 associated therewith. In other words, the dipole magnet 152 is configured to, for example, deflect the first ion beam 104 and the second ion beam 124 from the first beam path 106 and the second beam path 126, respectively, by the predetermined deflection angle 154. The predetermined deflection angle 154 is, for example, from about 70° to about 110°. In another example, the predetermined deflection angle 154 is less than 90°. In the example shown in Figures 1A-1B, the predetermined deflection angle 154 is 70° with an entrance pole rotation of about 45°.

[0039] As shown in Figures 2-6, the present disclosure further contemplates various architectures of the mass analysis magnet 130. For example, the mass analysis magnet 130 shown in Figure 4 has poles 156 (only one pole of two poles is shown in Figure 4). The poles are indexed in regions 158, 160, where the first ion beam 104 and the second ion beam 124 have approximately two gap distances from each other (e.g., shown as hatched regions). The poles 156 of the dipole magnet 152 may be planar, for example. Alternatively, the poles may be indexed or curved (not shown) based on the desired characteristics of the dipole magnet. Additionally, the present disclosure contemplates a mass analysis magnet 130 that is asymmetric, where the first ion source 102 and the second ion source 116 have different deflection angles 154 and / or pole face rotations.

[0040] The present disclosure contemplates that the first ion source 102 and the second ion source 116 generate X-ray radiation when forming the first ion beam 104 and the second ion beam 124. Such X-ray radiation may be dangerous to an operator when maintenance is performed on one of the first ion source 102 and the second ion source 116 while the other is in operation. Referring again to FIGS. 5 and 6, the present disclosure further provides one or more shields 180 disposed in one or more of the interior region 182 and the exterior region 184 of the mass analysis magnet 130, where the one or more shields are configured to block a line of sight between the first ion source 102 and the second ion source 116.

[0041] For example, the one or more shields 180 generally allow an operator to perform maintenance on the first ion source 102 while the second ion source 116 is operating (e.g., generating ions), and vice versa. For example, the one or more shields 180 allow removal / replacement of one ion source while the other ion source is warming up or operating, etc. The present disclosure further contemplates the provision of one or more radiation detectors 185 (e.g., one or more x-ray detectors) to indicate safe radiation levels during maintenance. The one or more radiation detectors 185 may be connected, for example, to an interlock system (not shown), which may allow access to the first ion source 102 and / or the second ion source 116 only when radiation levels have decreased below an acceptable safe level.

[0042] Additionally, the present disclosure allows for switching of beam species via the first ion source 102 and the second ion source 116 while safely maintaining one ion source while the other ion source is operating to form an ion beam. As a result, it is contemplated that an "infinite source life" or "zero down time" may be achieved. It is contemplated that the ion implantation system 100 of Figures 1A-1B may be operated continuously utilizing one of the first ion source 102 and the second ion source 116.

[0043] Referring again to FIG. 2, the inner region 182 and the outer region 184 are generally defined by, for example, one or more of the yoke 147, the coil 146, and the poles 156 of the mass analysis magnet 130. As an example, the one or more shields 180 include a central shield 186. As shown in FIG. 5, the central shield 186 is disposed in the inner region 182 of the mass analysis magnet between the first entrance 132 and the second entrance 134 of the mass analysis magnet 130. For example, the mass analysis beam path 150 defines an exit axis 188. In this case, the central shield 186 is disposed along the exit axis. The one or more shields 180 may further include, for example, one or more external magnet shields 190 disposed in the outer region 184 of the mass analysis magnet 130. The one or more external magnet shields generally extend from the mass analysis magnet, for example parallel to the exit axis 188. FIG. 2, for example, illustrates one or more external magnet shields 190 disposed in the exterior region 184 of the mass analysis magnet 130 .

[0044] In another example, as shown in FIG 1A, the first beam path 106 defines a first entrance axis 192, and as shown in FIG 1B, the second beam path defines a second entrance axis 194. Thus, for example, as shown in FIG 5 and FIG 6, the one or more shields 180 may further comprise a first entrance shield 196 and a second entrance shield 198 disposed along the first entrance axis 192 and the second entrance axis 194, respectively. In this example, the first entrance shield 196 and the second entrance shield 198 are illustrated as being disposed in the interior region 182 of the mass analysis magnet 130. However, alternatively, the first entrance shield and the second entrance shield may be disposed in the exterior region 184.

[0045] As another example, the one or more outer magnet shields 190 may have an exit aperture 200 as shown in Figure 2. The exit aperture is defined along the mass analysis beam path 150, allowing the ion beam 148 to exit the mass analysis magnet unobstructed after mass analysis.

[0046] As another example, any of the one or more external magnet shields 190 may include, for example, lead (Pb), which prevents X-ray radiation from penetrating the external magnet shield. For example, not shown, one or more shields 180 may include a graphite-backed lead sheet, which improves lead sputtering into the beamline while still providing adequate X-ray shielding. For example, the lead may be sandwiched between aluminum or other metals for additional rigidity and handling characteristics. Alternatively, one or more shields may include or be constructed of non-magnetic steel or any high-Z material (e.g., tungsten), which provides shielding against X-ray radiation.

[0047] The present disclosure contemplates that numerous other shapes and configurations of the mass analysis magnet 130 and the one or more shields 180 are possible, and that the one or more shields may be adapted to the configuration and arrangement of the analysis magnet and the first ion source 102 and second ion source 116, for example, by varying the configuration (arrangement) of the poles, yokes, coils, etc. It should be understood that all such configurations are contemplated as being within the scope of the present disclosure.

[0048] 1A-1B, as shown in these figures, according to further aspects of the present disclosure, a plurality of beamline components 140 are further disposed downstream of the mass analysis magnet 130. In this case, the plurality of beamline components are configured to direct the mass analyzed ion beam 148 towards a workpiece 204 disposed on a workpiece holder 206. The plurality of beamline components may include, for example, one or more of an accelerator, a decelerator, an energy filter, an aperture, a focusing lens, a steering lens, a measurement device, an angular energy filter, a measurement system, a scanner, and a calibrator.

[0049] According to yet another exemplary aspect of the present disclosure, the magnet control circuitry 142 may include any controller operably connected to the ion implantation system 100 for control of the system. For example, the controller may be operably connected to and configured to control any one or more of the first ion source 102, the second ion source 116, the first ion source arc current 110, the second ion source arc current 120, and a number of beamline components 140 (e.g., any extraction assemblies, apertures, focusing and / or steering elements, scanner devices, combination lens systems, energy resolution systems, beam and workpiece neutralization systems, measurement systems, workpiece holders, and translation systems).

[0050] 7 illustrates a method 500 for maintaining an ion implantation system in accordance with another exemplary embodiment of the present invention. Although the exemplary method is illustrated and described herein as a series of acts or events, it will be understood that the present invention is not limited by the illustrated order of the acts or events, as some steps may be performed in different orders and / or simultaneously with other steps other than those illustrated and described herein, in accordance with the present invention. In addition, not all illustrated steps may be required to implement a method in accordance with the present invention. Furthermore, it will be understood that the method may be performed in association with systems not illustrated, as well as systems not illustrated.

[0051] Method 500 may, for example, include providing one or more shields within a mass analysis magnet in Act 502 and applying a polarity of magnet current to the mass analysis magnet in Act 504. For example, a first ion source current may be applied to a first ion source in Act 506, which may form a first ion beam and direct the first ion beam along a first beam path toward a first entrance of the mass analysis magnet. In Act 508, the first ion beam is mass analyzed, where the first ion beam is deflected at an angle of about 70° to about 110°.

[0052] In Act 510, the first source current applied to the first ion source is terminated. This may cause the first ion beam to be extinguished. In Act 512, the polarity of the magnet current applied to the mass analysis magnet is reversed. In Act 514, a second source current is applied to the second ion source. This may cause a second ion beam to be formed and directed along a second beam path toward a second entrance of the mass analysis magnet. In Act 516, the second ion beam is further mass analyzed. In this case, the second beam path is also deflected by an angle of about 70° to about 110°.

[0053] For example, in Act 518, maintenance is safely performed on the first ion source along with the formation of the second ion beam, where the line of sight between the first ion source and the second ion source is interrupted by one or more shields disposed within the mass analysis magnet, thereby blocking x-rays from the second ion source.

[0054] It should be further appreciated that the methods described above may similarly be performed to safely maintain the second ion source. Thus, the systems and methods of the present disclosure provide for safe maintenance of each of the first and second ion sources while the other of the first and second ion sources is operating to form an ion beam and / or implant ions into a workpiece.

[0055] Although the present invention has been shown and described with respect to one or more specific preferred embodiments, it is apparent that equivalent changes and modifications will occur to those skilled in the art upon reading and understanding this specification and the accompanying drawings. In particular, with respect to the various functions performed by the above-described components (assemblies, devices, circuits, etc.), the terms used to describe such components (including references to "means") are intended, unless otherwise specified, to correspond to any component that performs the designated function of the described component (i.e., is functionally equivalent) even if it is not structurally equivalent to the disclosed structure that performs the function in the exemplary embodiment of the invention illustrated herein. In addition, although a particular configuration of the present invention may be disclosed with respect to only one of multiple embodiments, such configuration may be combined with one or more other configurations of other embodiments as desired and advantageous for any given or specific application. [Brief description of the drawings]

[0056] [Figure 1A] FIG. 1 is a schematic diagram illustrating an example of an ion implantation system having multiple ion sources and a single beamline in accordance with various aspects of the present invention. [Figure 1B] FIG. 1 is a schematic diagram illustrating an example of an ion implantation system having multiple ion sources and a single beamline in accordance with various aspects of the present invention. [Diagram 2] 1 is a schematic perspective view of an exemplary mass analysis magnet according to various aspects of the present invention; [Figure 3A]FIG. 2 is a schematic diagram of an exemplary mass analyzing magnet having a first polarity applied to a coil in accordance with various aspects of the present invention. [Figure 3B] FIG. 3B is a schematic diagram of the exemplary mass analysis magnet of FIG. 3A with a second polarity applied to the coils in accordance with various embodiments of the present invention. [Figure 4] 1 is a plan view in partial cross section of an exemplary mass analysis magnet according to various aspects of the present invention. [Diagram 5] FIG. 2 is a plan view in partial cross section of an exemplary mass analysis magnet having shielding in accordance with various aspects of the present invention. [Figure 6] FIG. 2 is a plan view in partial cross section of an exemplary mass analyzing magnet having multiple shields in accordance with various aspects of the present invention. [Figure 7] 4 illustrates an exemplary method for implanting ions into a workpiece in accordance with various further aspects of the present invention.

Claims

1. 1. An ion implantation system comprising: a mass spectrometry magnet; A first ion source; A second ion source; A magnet current source; A magnet control circuit; One or more shields; a plurality of beamline components; the mass analysis magnet comprising a yoke and a coil defining a first inlet, a second inlet and an outlet of the mass analysis magnet; the yoke and one or more of the coils define an interior and an exterior region of the mass analysis magnet; the first ion source defines a first ion beam along a first beam path toward the first entrance of the mass analyzing magnet; the second ion source defines a second ion beam along a second beam path toward the second entrance of the mass analyzing magnet; the magnet current source supplies a magnet current to the mass analysis magnet; the magnet control circuit is connected to the mass analysis magnet and to the magnet current source; the magnet control circuit selectively controls a polarity of the magnet current supplied to the mass analysis magnet based on the selective formation of the first ion beam and the second ion beam; the mass analysis magnet mass analyzes the first ion beam and the second ion beam, respectively, to define a mass analyzed ion beam at the exit of the mass analysis magnet along a mass analysis beam path; the one or more shields are disposed in one or more of the interior and exterior regions of the mass analysis magnet and block a line of sight between the first ion source and the second ion source; An ion implantation system, wherein a plurality of the beamline components are disposed downstream of the mass analyzing magnet and direct the mass analyzed ion beam toward a workpiece.

2. 2. The ion implantation system of claim 1, wherein the one or more shields include a central shield disposed in the interior region of the mass analysis magnet between the first and second entrances of the mass analysis magnet.

3. the mass analysis beam path defines an exit axis; The ion implantation system of claim 2 , wherein the center shield is disposed along the exit axis.

4. 4. The ion implantation system of claim 3, wherein the one or more shields further include one or more external magnet shields disposed in the outer region of the mass analysis magnet and extending generally perpendicular to the exit axis.

5. the first beam path defines a first entrance axis; the second beam path defines a second entrance axis; The ion implantation system of claim 4 , wherein the one or more shields further include a first entrance shield and a second entrance shield disposed along the first entrance axis and the second entrance axis, respectively.

6. The ion implantation system of claim 5 , wherein the first entrance shield and the second entrance shield are disposed in the interior region of the mass analyzing magnet.

7. The ion implantation system of claim 5 , wherein one or more of the external magnet shields are further disposed in the external region of the mass analysis magnet along the exit axis.

8. the first beam path defines a first entrance axis; the second beam path defines a second entrance axis; 2. The ion implantation system of claim 1, wherein the one or more shields include a first entrance shield and a second entrance shield disposed along the first entrance axis and the second entrance axis, respectively.

9. The ion implantation system of claim 1 , wherein the one or more shields include one or more external magnet shields disposed in the exterior region of the mass analysis magnet.

10. The ion implantation system of claim 9 , wherein one or more of the external magnet shields have an exit aperture defined along the mass analysis beam path.

11. The ion implantation system of claim 1 , wherein the one or more shields substantially block the transmission of x-ray radiation between the first ion source and the second ion source.

12. The ion implantation system of claim 1 , wherein the mass analyzing magnet comprises a dipole magnet having two poles that are substantially flat, indexed, or curved.

13. 13. The ion implantation system of claim 12, wherein the dipole magnet deflects each of the first ion beam and the second ion beam by a predetermined deflection angle of about 70° to about 110° when viewed from the first beam path and the second beam path, respectively.

14. The ion implantation system of claim 1 , wherein at least one of the one or more shields is constructed from lead.

15. The ion implantation system of claim 1 , wherein the plurality of beamline components comprises one or more of an accelerator, a decelerator, an energy filter, a lens, an aperture, a measurement system, a scanner, and a calibrator.

16. 1. An ion implantation system comprising: a mass spectrometry magnet; A first ion source; A second ion source; A magnet current source; A magnet control circuit; One or more shields; a plurality of beamline components; the mass analysis magnet comprising a yoke and a coil defining a first inlet, a second inlet and an outlet of the mass analysis magnet; the yoke and one or more of the coils define an interior and an exterior region of the mass analysis magnet; the first ion source defines a first ion beam along a first beam path toward the first entrance of the mass analyzing magnet; the second ion source defines a second ion beam along a second beam path toward the second entrance of the mass analyzing magnet; The magnet current source supplies a magnet current to the mass analysis magnet; the magnet control circuit is connected to the mass analysis magnet and to the magnet current source; the magnet control circuit selectively controls a polarity of the magnet current supplied to the mass analysis magnet based on the selective formation of the first ion beam and the second ion beam; the mass analysis magnet mass analyzes the first ion beam and the second ion beam, respectively, to define a mass analyzed ion beam at the exit of the mass analysis magnet along a mass analysis beam path; one or more of the shields block a line of sight between the first ion source and the second ion source; The one or more shields include: a central shield disposed in the interior region of the mass analysis magnet between the first entrance and the second entrance of the mass analysis magnet; a first entrance shield disposed along the first beam path; a second entrance shield disposed along the second beam path; one or more external magnet shields disposed in the exterior region of the mass analysis magnet and extending generally perpendicular to the mass analysis beam path; An ion implantation system, wherein a plurality of the beamline components are disposed downstream of the mass analyzing magnet and direct the mass analyzed ion beam toward a workpiece.

17. The ion implantation system of claim 16 , wherein the first entrance shield and the second entrance shield are disposed in the interior region of the mass analyzing magnet.

18. 17. The ion implantation system of claim 16, wherein one or more of the external magnet shields have an exit aperture defined along the mass analysis beam path.

19. the mass analysis magnet is generally flat, indexed, or curved and includes a dipole magnet having poles defined within an interior of the mass analysis magnet; 17. The ion implantation system of claim 16, wherein the dipole magnet deflects the first ion beam and the second ion beam, respectively, by a deflection angle of about 70° to about 110° when viewed from the first beam path and the second beam path, respectively.

20. 1. A method for maintaining an ion implantation system, comprising: applying a polarity of magnet current to a mass analysis magnet; providing one or more shields within the mass analysis magnet; forming a first ion beam by applying a first source current to a first ion source and directing the first ion beam along a first beam path towards a first entrance of the mass analyzing magnet; deflecting the first ion beam by less than 90° by mass analyzing the first ion beam; extinguishing the first ion beam by terminating the first source current applied to the first ion source; reversing the polarity of the magnet current applied to the mass analysis magnet; forming a second ion beam by applying a second source current to a second ion source and directing the second ion beam along a second beam path towards a second entrance of the mass analyzing magnet; deflecting the second beam path by less than 90° by mass analyzing the second ion beam; and performing maintenance of the first ion source while forming the second ion beam; A method in which, when performing maintenance on the first ion source, X-ray radiation from the second ion source is blocked by blocking a line of sight between the first ion source and the second ion source with one or more shields disposed inside the mass analysis magnet.

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