Minimum divergence ion beam adjustment device

Abstract

The ion implantation system includes an ion source configured to form an ion beam. A mass analyzer analyzes the ion beam, a scanning element scans the ion beam horizontally, and a collimating lens converts the fanned scanning beam into a parallel shifted scanning ion beam. For applications requiring not only a mean incidence angle but also a highly aligned ion incidence angle and tight angular distribution, a slit device is positioned at the horizontal and / or vertical front focal point of the collimating lens. The minimum horizontal and / or vertical angular distribution of the ion beam on the workpiece is achieved by controlling a beam focusing lens upstream of the scanning element for best beam transmission through the slit system.

Description

Detailed Description of the Invention

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Application No. 63 / 040,131, filed June 17, 2020, the entire contents of which are incorporated herein by reference in their entirety.

[0002] (Technical field) The present invention relates generally to ion implantation systems, and more particularly to a system and method for controlling the beam angle of an ion beam in an ion implantation system.

[0003] (Background technology) In semiconductor device manufacturing, ion implantation is used to dope semiconductors with impurities or dopants. Ion beam implanters are used to process silicon wafers with ion beams. This can result in n-type or p-type extrinsic material doping or the formation of passivation layers during integrated circuit fabrication. When used to dope semiconductors, ion beam implanters implant selected exogenous species to produce the desired semiconductor material. Implanting ions generated from source materials such as antimony, arsenic, or phosphorus results in "n-type" extrinsic material wafers, while if "p-type" extrinsic material wafers are desired, ions generated from source materials such as boron or indium can be implanted.

[0004] A typical ion beam implanter includes an ion source for generating positively charged ions from an ionizable source material. The generated ions are formed into a beam and directed along a predetermined beam path to an implantation station. The ion beam implanter may include a beam forming and shaping structure extending between the ion source and the implantation station. The beam forming and shaping structure maintains the ion beam and defines an elongated internal cavity or passageway through which the beam passes on its way to the implantation station. When operating the implanter, this passageway may be evacuated to reduce the probability that ions will be deflected from the predetermined beam path as a result of collisions with gas molecules.

[0005] The trajectories of charged particles of a given kinetic energy in a magnetic field differ depending on their different masses (or charge-to-mass ratios). Therefore, the portion of the extracted ion beam that reaches a desired area of ​​a semiconductor wafer or other target after passing through a constant magnetic field can be purified because ions of undesired molecular weights are deflected away from the beam, avoiding implantation of non-desired materials. The process of selectively separating ions of desired and undesired charge-to-mass ratios is known as mass analysis. Mass analyzers typically use a mass analysis magnet that generates a dipole magnetic field to deflect various ions in an ion beam via magnetic deflection in an arcuate path, effectively separating ions of different charge-to-mass ratios.

[0006] In some ion implantation systems, the physical size of the beam is smaller than the target workpiece, and therefore the beam is scanned in one or more directions to adequately cover the surface of the target workpiece. Typically, an electrostatic or magnetic-based scanner scans the ion beam in a fast direction, while a mechanical device moves the target workpiece in a slow scan direction to provide sufficient coverage.

[0007] The ion beam is then directed toward a target end station, which holds a target workpiece. The ions in the ion beam are implanted into the target workpiece, resulting in ion implantation. One of the key characteristics of ion implantation is the presence of a uniform angular distribution of ion flux across the entire surface of the target workpiece (e.g., a semiconductor wafer). The angular content of the ion beam determines the implant characteristics through crystalline channeling or shadowing effects under vertical structures such as photoresist masks or CMOS transistor gates. Non-uniform angular distribution or angular content of the ion beam can result in uncontrolled and / or undesirable implant characteristics.

[0008] To prevent the risk of energy contamination, angle correction may be used when a deflection deceleration lens is implemented. Energy contamination can be considered as the content of ions with undesired energies (typically higher than the desired energy), resulting in improper dopant placement within the workpiece. This may further lead to undesired device performance or even device damage.

[0009] (Summary of the Invention) The present disclosure thus provides ion implantation systems and methods for minimizing the angular distribution (also called divergence) of an ion beam, such as when using channeling through crystalline structures within a workpiece. Accurate and rapid tuning of the ion beam, achievable by the disclosed systems and methods, is thus achieved, whereby tight angular distribution of the ion beam can be achieved by a removable slit at the pre-focus of the last ion beam focusing element in the beam transport system.

[0010] Accordingly, the following presents a simplified summary of the invention 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 or critical elements of the invention, nor is it intended 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.

[0011] The ion implantation system includes an ion source configured to form an ion beam. A mass analyzer analyzes the ion beam, a scanning element scans the ion beam horizontally, and a collimating lens converts the fanned scanning beam into a parallel shifted scanning ion beam. It should be understood that in some applications, it may be advantageous for ion trajectories to have highly aligned angles of incidence across the workpiece, as opposed to a mean or average angle of incidence across the workpiece, while also having a very tight angular distribution. Therefore, a slit device is positioned at one or more of the horizontal or vertical front foci of the collimating lens. Minimizing horizontal and / or vertical angular distribution of the ion beam on the workpiece is further achieved by adjusting or otherwise controlling a beam focusing lens (e.g., a quadrupole lens) upstream of the scanning element for best beam transmission through the slit device.

[0012] According to an exemplary aspect of the present disclosure, there is provided an ion implanter for implanting ions into a workpiece. The ion implanter includes, for example, an ion source configured to form an ion beam and a mass analyzer configured to mass analyze the ion beam. The scanning element is configured to scan the ion beam in a horizontal direction, the ion beam having respective focal points in the horizontal and vertical directions. The slit device has, for example, an aperture selectively positioned downstream of the scanning element at one or more of the respective focal points of the ion beam in the horizontal and vertical directions. Furthermore, a collimation optical system is provided downstream of the slit device and configured to collimate the ion beam, thereby minimizing an angular distribution in one or more of the horizontal and vertical directions.

[0013] In one example, the ion beam comprises a pencil beam or a spot beam. In another example, the slit device comprises a plate having an aperture defined therein. For example, a movement device may further be provided and configured to selectively position the plate, such as with respect to the ion beam. For example, the movement device may comprise a rotational movement device configured to selectively rotate the plate into and out of the path of the ion beam. In another example, the movement device may comprise a linear movement device configured to selectively linearly move the plate into and out of the path of the ion beam. The scanning element may be configured, for example, to provide a fan-shaped scanned beam.

[0014] In another example, a quadrupole lens is provided upstream of the scanning element, the scanning element being configured to provide the horizontal and vertical angular distribution of the ion beam. A controller is further provided and configured to control one or more of the scanning mechanism, the quadrupole lens, and the position of the aperture of the slit device to maximize the beam current of the ion beam and minimize the angular distribution of the ion beam at the workpiece. In another example, the controller is configured to control one or more of the ion source, the mass analyzer, the scanning element, the slit device, and the collimation optics to maximize the beam current of the ion beam and minimize the angular distribution of the ion beam at the workpiece.

[0015] According to another exemplary aspect of the present disclosure, there is provided an ion implantation system including: an ion source configured to form an ion beam; a mass analyzer configured to mass analyze the ion beam; and a scanning element configured to scan the ion beam in a horizontal direction, the ion beam having respective focal points in the horizontal and vertical directions. A collimation optical system is provided downstream of the slit device and configured to collimate the ion beam, such that the collimation optical system defines one or more of a vertical focus and a horizontal focus upstream thereof, thereby minimizing angular distribution in the one or more of the horizontal and vertical directions. Furthermore, a slit device having an aperture is selectively positioned at one or more of a scan apex of the scanning element and the vertical focus of the ion beam.

[0016] The slit device may, for example, comprise a plate having an opening defined therein. A moving device may be further configured to selectively position the plate. The moving device may, for example, comprise a rotary motion device configured to selectively rotate the plate into and out of the path of the ion beam. In an alternative example, the moving device may comprise a linear motion device configured to selectively linearly move the plate into and out of the path of the ion beam.

[0017] In another example, a quadrupole lens is disposed upstream of the slit device, the quadrupole lens configured to provide horizontal and vertical focusing at an aperture to minimize the angular distribution of the ion beam in the horizontal and vertical directions, respectively. In another example, a controller is configured to control one or more of the quadrupole lens, the collimating optics, and the position of the aperture of the slit device to maximize beam current of the ion beam and minimize the angular distribution of the ion beam at the workpiece.

[0018] According to yet another aspect of the present disclosure, there is provided a method for minimizing the angular distribution of an ion beam. The method includes, for example, focusing an ion beam to a focal point upstream of a corrector magnet. A slit is selectively positioned at the focal point of the ion beam. Furthermore, a quadrupole lens upstream of the slit is controlled to maximize beam current of the ion beam and minimize the angular distribution of the ion beam at a workpiece positioned downstream of the corrector magnet. Controlling the quadrupole lens, for example, independently varies the focal point to maximize transmission of the ion beam through the slit.

[0019] To the accomplishment of the foregoing and related ends, the present disclosure comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail illustrative embodiments of the invention. These embodiments, however, are indicative of but some of the various ways in which the principles of the invention are 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.

[0020] BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an example of an ion implantation system according to one embodiment of the present disclosure.

[0021] FIG. 2 is a schematic diagram illustrating a finite beam angle distribution according to one embodiment of the present disclosure.

[0022] FIG. 3 is a schematic diagram of a scanned ion beam showing implant angles according to one embodiment of the present disclosure.

[0023] FIG. 4 is a schematic diagram of a scanned ion beam illustrating implantation angles incorporating a slit for horizontal divergence according to one embodiment of the present disclosure.

[0024] FIG. 5 is a schematic diagram of a scanned ion beam showing a vertical divergence slit according to one embodiment of the present disclosure.

[0025] FIG. 6A is a simplified perspective view of an example of a vertical divergence slit arrangement for controlling implant angle according to one embodiment of the present disclosure.

[0026] FIG. 6B is a top view of an example of a vertical divergence slit arrangement according to another embodiment of the present disclosure.

[0027] FIG. 6C is a side view of the vertical divergence slit device of FIG. 6B according to yet another embodiment of the present disclosure.

[0028] (Mode for Carrying Out the Invention) The present disclosure provides ion implantation systems and methods for controlling (e.g., minimizing) the angular distribution (e.g., divergence) of an ion beam, such as when using channeling through crystalline structures in a workpiece. Additionally, the present disclosure provides systems and methods for precisely and quickly adjusting an ion beam to achieve tight angular distributions of the ion beam by implementing a removable slit downstream in an ion beam transport system or at the pre-focus point of the final focusing element.

[0029] Accordingly, the present invention will now be described with reference to the drawings, wherein like reference numerals may be used to refer to like elements throughout. It should be understood that these descriptions of embodiments are 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 those skilled in the art that the present invention may be practiced without these specific details. Furthermore, the scope of the present invention is not limited by the embodiments or examples described below. However, it is intended that the present invention be limited only by the appended claims and equivalents thereof.

[0030] It should also be noted that the drawings are provided to illustrate some aspects of embodiments of the present invention and should therefore be considered to be schematic only. In particular, the elements shown in the drawings are not necessarily to scale relative to each other, and the arrangement of various elements in the drawings is selected to provide a clear understanding of each embodiment. The arrangement of various components in the drawings should not necessarily be construed as a representation of the actual relative positions of various components in an implementation according to one embodiment of the present invention. Furthermore, features of various embodiments and examples described herein can be combined with each other unless otherwise specified.

[0031] It should also be understood that in the following description, any direct connection or coupling between functional blocks, devices, components, circuit elements, or other physical or functional units shown in the drawings or described herein may also be implemented by an indirect connection or coupling. Furthermore, it should be appreciated that functional blocks or units shown in the drawings may be implemented as separate features or circuits in one embodiment, or alternatively, may be fully or partially implemented in a common feature or circuit in another embodiment. For example, some functional blocks are examples that may be implemented as software running on a common processor, such as a signal processor. Furthermore, it should be understood that any connection described in the following specification as being wire-based may also be implemented as wireless communication, unless indicated to be inconvenient.

[0032] The present disclosure recognizes that to achieve a high degree of channeling through the crystalline lattice structure, especially at high energies, the ion beam should be angularly aligned with the crystalline lattice structure of the workpiece. Various examples of channeling concepts and ion implantation systems are provided in commonly owned U.S. Patent No. 9,711,328 to Satoh, which is incorporated herein by reference in its entirety.

[0033] The present disclosure further recognizes that such alignment of the ion beam includes not only the average or mean angle of the ion beam relative to the crystal lattice, but also its distribution. For example, for very high-energy arsenic (As) implants, greater than about 10 MeV, the ions within the ion beam should have a tight angular distribution to provide a desirable channeling depth profile, such as an angular distribution with a standard deviation of less than about 0.1 degrees.

[0034] Conventionally, implant angle control has been primarily concerned with controlling the average incident angle of the entire ion beam, and little attention has been paid to its distribution. However, with the recent spread of channeling implants, issues related to implant angle distribution have become more important, and it has also become more important to reliably obtain an ion beam with a fairly narrow angle distribution.

[0035] Tuning an ion beam to provide a very small angular distribution has traditionally been a laborious trial-and-error process; that is, repeated cycles of almost blindly changing parameters, measuring the resulting ion beam angular distribution, and continuing to modify the parameters until the appropriate distribution is achieved. The present disclosure provides a rapid solution to the traditional slow and unreliable tuning process for minimizing angular distribution. The present invention provides a basis for tuning vertical beam divergence in ion implantation systems, such as, by way of non-limiting example, the Purion XE / VXE / XEmax (manufactured by Axcelis Technologies, Inc., Beverly, Massachusetts).

[0036] To better understand the present disclosure, an ion implantation system 100 according to various embodiments of the present disclosure is shown in Figure 1. It will be understood that the ion implantation system 100 is provided for illustrative purposes and is not limited to the ion implantation system described in this embodiment, and that other suitable ion implantation systems of various configurations may also be used.

[0037] The ion implantation system 100 is shown to include a terminal 102, a beamline assembly 104, and an end station 106. The terminal 102, by way of example, includes an ion source 108 powered by a high-voltage power supply 110, which generates an ion beam 112 that is directed through the beamline assembly 104 and ultimately to the end station 106. By way of example, the ion beam 112 may take the form of a spot beam, a pencil beam, a ribbon beam, or any other shaped beam. The beamline assembly 104 further includes a beam guide 114 and a mass analyzer 116, where a dipole magnetic field is established to pass only ions of an appropriate charge-to-mass ratio through an opening 118 at the exit end of the beam guide 114 to define a mass-analyzed ion beam 135 that is directed to a workpiece 120 (e.g., a semiconductor wafer, a display panel, etc.) disposed within the end station 106.

[0038] According to one embodiment, an ion beam scanning system 122 (collectively referred to as a "scanner" or "scanning element"), such as an electrostatic scanner or an electromagnetic scanner, is configured to scan the ion beam 112 relative to the workpiece 120 in at least a first direction 123 (e.g., + / - directions of the y-axis, also referred to as a first scan path or "fast scan" axis, path, or direction) to define a ribbon-shaped ion beam or scanned ion beam 124 (e.g., a fanned-out scanned ion beam). Further, in this embodiment, a workpiece scanning system 126 is provided and configured to selectively scan the workpiece 120 through the ion beam 112 in at least a second direction 125 (e.g., + / - directions of the x-axis, also referred to as a second scan path or "slow scan" axis, path, or direction). In one embodiment, the ion beam scanning system 122 and the workpiece scanning system 126 may be positioned separately or in conjunction with one another to provide a desired scanning of the workpiece relative to the ion beam 112. In another embodiment, the ion beam 112 is electrostatically scanned in a first direction 123 to generate a scanned ion beam 124, and the workpiece 120 is mechanically scanned in a second direction 125 through the scanned ion beam 124. Such a combination of electrostatic and mechanical scanning of the ion beam 112 and workpiece 120 generates so-called "hybrid scanning." The present invention is applicable to all combinations of scanning the workpiece 120 relative to the ion beam 112, and vice versa. Additionally, a controller 130 is provided, configured to control one or more components of the ion implantation system 100.

[0039] According to one exemplary aspect of the present invention, there is also provided a beam measurement system 150. The beam measurement system 150, in one example, is configured to determine one or more characteristics associated with the ion beam 112. Systems and methods for measuring the angle of ions incident on the workpiece 120 and calibration of said measurements to crystallographic planes of the workpiece are provided in the so-called "Prion XE" ion implantation system and commonly owned U.S. Patent No. 7,361,914 to Robert D. Rathmell et al., the contents of which are incorporated herein by reference in their entirety.

[0040] In this manner, the mass analyzer 116 passes ion species within the ion beam 112 having a desired charge-to-mass ratio to define a mass-analyzed ion beam 135 that exits through the aperture 118. While not shown, the mass-analyzed ion beam 135 is, in one example, accelerated to a desired energy and further focused by a beam-focusing lens (e.g., a quadrupole lens) before entering the scanning element 122. The scanned ion beam 124 then passes through a collimator 160 (e.g., a component that performs collimation and correction, also referred to as a "corrector magnet"), which in the illustrated embodiment comprises two dipole magnets 162A and 162B. The dipole magnets 162A and 162B are, for example, substantially trapezoidal and oriented as mirror images of each other to bend the scanned ion beam 124 into a substantially S-shape. In other words, the dipole magnets 162A and 162B have a configuration with equal angles and radii and opposite directions of curvature.

[0041] The collimators 160, by way of example, change the beam path of the scanned ion beam 124 so that the mass-analyzed beam travels parallel to the beam axis regardless of the scan angle. As a result, the implantation angle is uniform across the workpiece 120. In one example, one or more of the collimators 160 also act as deflection components, such that there is nearly zero chance that neutral particles generated upstream of the collimators will reach the end station 106 and workpiece 120 by not following their nominal path.

[0042] It will be appreciated that the one or more so-called corrector magnets or collimators 160 may comprise any suitable number of electrodes or magnets positioned and biased to focus, bend, deflect, converge, diverge, scan, collimate, and / or decontaminate the ion beam 112. The end station 106 then receives the mass-analyzed ion beam 135 directed toward the workpiece 120. It will be appreciated that different types of end stations 106 may be used in the ion implantation system 100. As one example, a "batch" type end station may simultaneously support multiple workpieces 120 on a rotating support mechanism, where the workpieces are rotated through the path of the ion beam 112 until all workpieces are fully implanted. On the other hand, a "serial" type end station supports a single workpiece 120 along the beam path for implantation, where multiple workpieces are implanted sequentially, one at a time, with each workpiece being fully implanted before the implantation of the next workpiece begins. In a hybrid system, the workpiece 120 is mechanically translated in a first direction (e.g., along the y-axis, also called the slow scan or vertical direction) while the beam is scanned in a second direction (e.g., along the x-axis, also called the fast scan or horizontal direction) to impart the ion beam 112 across the workpiece.

[0043] 1 is a "continuous" type end station that supports a single workpiece along the beam path for implantation. A beam measurement system 150 may further be included in the end station 106 near the location of the workpiece 120 for calibration measurements performed prior to the implant process. During calibration, the ion beam 112 passes through the beam measurement system 150. In one embodiment, the beam measurement system 150 includes one or more profilers that may be stationary or that continuously traverse a profiler path to measure the profile of the ion beam 112 (e.g., a scanned or unscanned spot or pencil beam).

[0044] Ions in the ion beam 112 generally travel in the same direction with some distribution (e.g., divergence) around the mean value of the angular distribution. Therefore, the present disclosure contemplates that a consistent angle of incidence across the surface of the workpiece 120, i.e., the mean angle of the distribution, is an important consideration during ion implantation. Furthermore, for example, the fidelity or tightness of the ion beam's angular distribution determines implantation characteristics due to crystal channeling or shadowing effects under vertical structures such as photoresist masks or CMOS transistor gates. An ion beam 112 without controlled angular distribution can, for example, result in uncontrolled and undesirable implantation characteristics.

[0045] Therefore, the angle of incidence (average angle of the distribution) and angular distribution of the ion beam 112 are measured with high precision using various beam diagnostic devices, some of which are described above. The measurement data can then be used in an angle correction method. Once the correction is applied, the measurement of the beam angle and its adjustment are repeated until the desired beam angle characteristics, average angle, and narrow distribution are achieved.

[0046] Some implantation systems utilize, for example, one or more corrector magnets or collimators 160 (see FIG. 1 ) to convert a horizontally fanned beam into a parallel, shifted, scanned beam. The collimating function or optics can be viewed as a positive focusing lens system 200 including collimating optics 202 (also referred to as a collimating lens), as shown in FIG. 2 . The collimating optics 202 may, for example, include or consist of the corrector magnets or collimators 160 (see FIG. 1 ). In one example, the collimating optics 202 are configured to obtain a nearly constant “average” implant angle across the entire width of the workpiece 120. In one example, the front focus 204 or positive lens of the corrector magnet 160 is positioned at the scan vertex 154 of the scanner or scanning element 122. As shown in FIG. 2 as an idealized case, each line 206 of the ion beam 112 represents the ion beam 112 having a “zero” angular distribution, i.e., a substantially small angular distribution 208 of the ion beam 112 in the horizontal direction (e.g., the x-direction shown in FIG. 2 ).

[0047] 3 illustrates an example in which an incident ion beam 209 (e.g., mass analysis ion beam 135) has a finite angular distribution 210. In such an example, when incident ion beam 209 with finite angular distribution 210 is focused at the same scan apex position (shown in FIG. 3 as a cone 212 emanating from scan apex 154), final ion beam 213 on workpiece 120 also has finite angular distribution 210. The degree of angular distribution of final ion beam 213 depends on how well incident ion beam 209 is focused at scan apex 154.

[0048] In accordance with the present disclosure, FIG. 4 illustrates an example in which a slit 214 (e.g., a slit defined in a retractable plate having an aperture configured to allow movement of the scanning element 122) is located at the scan apex 154. According to this example, various lenses upstream of the scanning element are adjusted or otherwise controlled to focus or otherwise provide maximum propagation of the incident ion beam 209 through the slit. Thus, the ion beam 112 has the lowest angular distribution 216 relative to the workpiece 120. Accordingly, the example of FIG. 4 illustrates a horizontal angular dispersion minimizer 218. It is understood that various technical considerations exist in designing the slit 214 illustrated in FIG. 4 , such as being retractable at the scan apex 154, while also providing for movement of the scanning element 122 during normal operation of the ion implanter in a high-pressure environment. The present disclosure contemplates such a system providing the desired minimization of the angular distribution of the ion beam 112.

[0049] FIG. 5 illustrates one embodiment of a vertical angular distribution minimization device 220. In the vertical direction (e.g., the y direction shown in FIG. 5), the corrector magnet 160 may be configured to provide, for example, a strong positive focusing force, thereby allowing the corrector magnet to be utilized to minimize the vertical beam angular distribution 222 using principles similar to those used in the horizontal direction, as described above. Accordingly, the present disclosure provides a vertical divergence slit (VDS) device 224 (also referred to as a retractable slit device) for minimizing the vertical beam angular distribution 222. In one embodiment, the VDS device 224 is positioned immediately after the exit 226 of the scanning element 122, also in close proximity to the vertical front focal point of the lens of the corrector magnet 160. The focusing force (e.g., the so-called "S-bend") of the corrector magnet 160 is, for example, sufficient such that the slit 214 of the VDS device 224 is positioned at its focal point 228 at the exit 226 of the scanning element 122. The VDS device 224 may, for example, be selectively removable from the path of the ion beam 112, thereby allowing the slit 214 of the VDS device to be selectively translated, rotated, or otherwise moved or removed from the path of the ion beam, as shown, by way of example, by arrow 229. The slit 214 of the VDS device 224 may, for example, be configured to be selectively positioned, translated, and / or rotated along or about any of the x-axis, y-axis, or z-axis.

[0050] It should be noted that while particular ion implantations are specifically discussed herein, for example, other ion implantation systems may utilize a system similar to that described above to minimize the angular distribution of the final beam in either the horizontal or vertical direction, whereby a slit is provided at the pre-focus point of the final positive lens in the respective horizontal or vertical direction.

[0051] In one embodiment, the VDS device 224 is provided after the scanning element 122 because the vertical focal length is stronger and therefore the slit 214 is located closer to the corrector magnet 160. Accordingly, adjustments of the ion beam 112 can be made before or after the scanning element 122, for example, via a quadrupole lens (not shown), thereby allowing the slit 214 to be moved away after the adjustment, thereby allowing ion implantation into the workpiece 120 to continue. When adjusting, the slit 214 is positioned along the beamline, and an upstream lens (not shown) can be adjusted in a point-wise manner to focus. The beam current of the ion beam 112 can then be measured so that propagation through the slit 214 is optimized (e.g., resulting in maximized beam current), thus providing an indication that the ion beam is minimally diverging through the slit. Accordingly, the present disclosure provides an angular distribution control adjustment assistance device.

[0052] 6A-6C illustrate another embodiment of a vertical angular distribution minimization device 300 according to various aspects of the present invention. In summary, FIG. 6A illustrates a vertical angular distribution minimization system 300 whereby an ion beam 112 passes through a quadrupole lens 302 and is then scanned horizontally (e.g., in the x-direction) by a scanning element 122. In one embodiment, a VDS device 224 is selectively positioned (e.g., as indicated by arrow 229) such that the horizontal and vertical dimensions 304 and 306 of the slit 214 primarily limit the vertical height (e.g., in the y-direction) of the scanned ion beam 124 while still permitting the entire scan width of the ion beam 112 in the horizontal direction. In one embodiment, the scan apex 154 coincides with the horizontal front focal point 308 of the collimating optics 202.

[0053] 6B shows a top view 310 of the vertical angular distribution minimization system 300 of FIG. 6A, in which the scanned ion beam 124 is horizontally unobstructed by the slit 214 of the VDS device 224. The scan apex 154, i.e., the horizontal bending point of the scanning element 122, is located at the horizontal front focal point 308 of the collimation optics 202. For purposes of illustration, the collimation optics 202 is shown as a simple positive focusing lens, although other lens systems are contemplated. For example, the quadrupole lens 302 focuses the ion beam 112 at the scan apex 154. This results in a final ion beam 213 from the collimation optics 202 that is horizontally parallel and has minimal angular distribution.

[0054] 6C shows a side view 312 of the vertical angular distribution minimization system 300 of FIG. 6A . The slit 214 of the VDS device 224 is positioned at the vertical front focal point 314 of the collimation optics 202 (e.g., as indicated by arrow 229) when the quadrupole lens 302 vertically focuses the ion beam 112 at the VDS slit. It should be understood that, as an example, the VDS device 224 can include a movement device 316 comprising one or more linear actuators, rotary actuators, gears, linkages, and / or other mechanisms operably coupled to a plate 318 on which the slit 214 is defined, as well as one or more controllers or other control mechanisms. This allows the VDS device to selectively position the slit 214 at the vertical front focal point 314 and the scan apex 154. Thus, the final ion beam 213 exiting the collimation optics 202 is advantageously parallel in the vertical direction while also having a minimal angular distribution in the vertical direction, as described above. The VDS device 224 may further be removed from the path of the ion beam 112 if desired.

[0055] Thus, the present disclosure provides advantages over traditional iterative trial and error processes, thus quickly achieving faster and easier adjustments of ion implantation systems in real time.

[0056] While the present invention has been illustrated and described with respect to one or more embodiments, changes and / or modifications can be made to the illustrated examples without departing from the spirit and scope of the appended claims. In particular, with regard to the various functions performed by the above-described components or structures (blocks, units, engines, assemblies, devices, circuits, systems, etc.), the terms used to describe such components (including references to "means"), unless otherwise indicated, are intended to correspond to any component or structure that performs the specified function (e.g., is functionally equivalent) of the described component, but is not structurally equivalent to the disclosed structure that performs that function in the exemplary implementations of the invention illustrated herein.

[0057] Additionally, while a particular feature of the invention may be disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of other implementations, as may be desirable and advantageous for any given or particular application. The word "exemplary," as used herein, is intended to mean an example, as opposed to best or best. Furthermore, to the extent that the terms "including," "includes," "having," "has," "with," or the like, are used in either the detailed description or the claims, such terms are equivalent to the term "comprising." [Brief explanation of the drawings]

[0058] [Figure 1] 1 illustrates an example of an ion implantation system according to one aspect of the present disclosure. [Figure 2] FIG. 1 is a schematic diagram illustrating a finite beam angle distribution according to one aspect of the present disclosure. [Figure 3] FIG. 1 is a schematic diagram of a scanned ion beam showing implantation angles according to one aspect of the present disclosure. [Figure 4] FIG. 1 is a schematic diagram of a scanned ion beam illustrating implantation angles incorporating a slit for horizontal divergence according to one aspect of the present disclosure. [Figure 5] FIG. 1 is a schematic diagram of a scanned ion beam showing a vertical divergence slit according to one aspect of the present disclosure. [Figure 6A] FIG. 1 is a simplified perspective view of an example of a vertical divergence slit arrangement for controlling implant angle according to an aspect of the present disclosure. [Figure 6B] FIG. 10 is a top view of an example of a vertical divergence slit apparatus according to another aspect of the present disclosure. [Figure 6C] FIG. 6C is a side view of the vertical divergence slit device of FIG. 6B according to yet another embodiment of the present disclosure.

Claims

1. 1. An ion implantation system for implanting ions into a workpiece, comprising: an ion source configured to form an ion beam; a mass analyzer configured to mass analyze the ion beam; a scanning element configured to scan the ion beam in a horizontal direction such that the ion beam has a focal point in each of the horizontal and vertical directions; a slit device having an aperture selectively positioned at one or more of the focal points of the ion beam in the horizontal and vertical directions, respectively, and downstream of the scanning element; a collimation optical system disposed downstream of the slit device and configured to collimate the ion beam such that angular distribution in one or more of the horizontal and vertical directions is minimized; and An ion implantation system comprising:

2. The ion implantation system of claim 1 , wherein the ion beam comprises a pencil beam or a spot beam.

3. The ion implantation system of claim 1 , wherein the slit arrangement comprises a plate having the aperture defined therein.

4. The ion implantation system of claim 3 , further comprising a translation device configured to selectively position the plate.

5. 5. The ion implantation system of claim 4, wherein the translator comprises a rotary translator configured to selectively rotate the plate into and out of the path of the ion beam.

6. 5. The ion implantation system of claim 4, wherein the translation device comprises a linear translation device configured to selectively translate the plate linearly into and out of the path of the ion beam.

7. The ion implantation system of claim 1 , wherein the scanning element is configured to define a fanned scanning beam.

8. a quadrupole lens upstream of the scanning element; a control device; and the scanning element is configured to provide an angular distribution of the ion beam in the horizontal and vertical directions; 2. The ion implantation system of claim 1, wherein the controller is configured to control one or more of the scanning element, the quadrupole lens, and the position of the aperture of the slit device to maximize beam current of the ion beam and minimize the angular distribution of the ion beam at the workpiece.

9. 10. The ion implantation system of claim 1, further comprising a controller configured to control one or more of the ion source, the mass analyzer, the scanning element, the slit arrangement, and the collimation optics to maximize beam current of the ion beam and minimize angular distribution of the ion beam at the workpiece.

10. 1. An ion implantation system for implanting ions into a workpiece, comprising: an ion source configured to form an ion beam; a mass analyzer configured to mass analyze the ion beam; a scanning element configured to scan the ion beam horizontally from a scan apex; collimation optics downstream of the scanning element and configured to collimate the ion beam, the collimation optics defining one or more of a vertical focus of the ion beam in a vertical direction and a horizontal focus of the ion beam in the horizontal direction, the vertical focus and the horizontal focus being upstream of the collimation optics; a slit device having an aperture selectively positioned at one or more of the scan apex and the vertical focus of the ion beam, thereby minimizing an angular distribution of the ion beam in one or more of the horizontal and vertical directions; An ion implantation system comprising:

11. The ion implantation system of claim 10 , wherein the ion beam comprises a pencil beam or a spot beam.

12. The ion implantation system of claim 10 , wherein the slit arrangement comprises a plate having the aperture defined therein.

13. The ion implantation system of claim 12 , further comprising a translation device configured to selectively position the plate.

14. 14. The ion implantation system of claim 13, wherein the translator comprises a rotary translator configured to selectively rotate the plate into and out of the path of the ion beam.

15. 14. The ion implantation system of claim 13, wherein the translation device comprises a linear translation device configured to selectively translate the plate linearly into and out of the path of the ion beam.

16. The ion implantation system of claim 10 , wherein the scanning element is configured to provide a fanned scanning beam.

17. further comprising a quadrupole lens disposed upstream of the slit device; 11. The ion implantation system of claim 10, wherein the quadrupole lens is configured to provide horizontal and vertical focusing at the aperture to minimize an angular distribution of the ion beam in the horizontal and vertical directions, respectively.

18. Further comprising a control device, 18. The ion implantation system of claim 17, wherein the controller is configured to control one or more of the quadrupole lens, the collimating optics, and the position of the aperture of the slit device to maximize beam current of the ion beam and minimize the angular distribution of the ion beam at the workpiece.

19. 1. A method for minimizing an angular distribution of an ion beam on a workpiece, comprising: focusing the ion beam at a focal point upstream of a corrector magnet; selectively positioning a slit at the focal point of the ion beam; and controlling a quadrupole lens upstream of the slit such that a beam current of the ion beam is maximized and an angular distribution of the ion beam is minimized at the workpiece positioned downstream of the corrector magnet.

20. 20. The method of claim 19, wherein controlling the quadrupole lenses independently varies the focal points to maximize transmission of the ion beam through the slit.

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