Adjustment device for minimum divergence ion beam

Abstract

Ion implantation system with an ion source configured to form an ion beam. A mass analyzer mass analyzes the ion beam, a scanning element scans the ion beam in a horizontal direction, and a parallelizing lens converts the fan-out scanned beam into a parallel moving scanned ion beam. For applications requiring not only an average angle of incidence but also a highly aligned ion angle of incidence and a tight angular distribution, a slit device is placed at the horizontal and / or vertical front focal point of the parallelizing lens. The minimum horizontal and / or vertical angular distribution of the ion beam on the workpiece is achieved by controlling the beam focusing lens upstream of the scanning element to obtain the best beam transmission through the slit system.

Description

[0001] Citation of relevant applications

[0002] This application claims priority to U.S. Provisional Application 63 / 040,131, filed June 17, 2020, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The present invention relates generally to ion implantation systems, and more specifically to systems and methods for controlling the beam angle of an ion beam in an ion implantation system. Background Technology

[0004] 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 to produce n-type or p-type intrinsic material doping or to form passivation layers during integrated circuit manufacturing. When used for doping semiconductors, ion beam implanters implant selected intrinsic materials to produce the desired semiconductor material. Implanting ions from source materials such as antimony, arsenic, or phosphorus produces “n-type” intrinsic material wafers, while if “p-type” intrinsic material wafers are required, ions from source materials such as boron or indium can be implanted.

[0005] A typical ion beam implanter includes an ion source for generating positively charged ions from an ionizable source material. The generated ions form a beam and are guided 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 holds the ion beam and defines an elongated internal cavity or channel through which the beam passes on its way to the implantation station. When operating the implanter, the channel can be evacuated to reduce the likelihood of ions deflecting the predetermined beam path due to collisions with gas molecules.

[0006] In a magnetic field, the trajectory of a charged particle with a given kinetic energy will differ depending on its mass (or charge-to-mass ratio). Therefore, after passing through a constant magnetic field, the extracted ion beam can be partially purified to a desired region on a semiconductor wafer or other target, as ions with unwanted molecular weights are deflected away from the beam, and the injection of ions different from the desired material is avoided. The process of selectively separating desired and unwanted charge-to-mass ratio ions is called mass analysis. Mass analyzers typically employ mass analysis magnets that generate a dipole magnetic field, which deflects various ions in the ion beam through magnetic deflection in an arc-shaped channel, effectively separating ions with different charge-to-mass ratios.

[0007] For some ion implantation systems, the physical size of the beam is smaller than the target workpiece, so the beam scans in one or more directions to adequately cover the surface of the target workpiece. Typically, an electrostatic or magnetic scanner scans the ion beam in a fast direction, while a mechanical device moves the target workpiece in a slow scanning direction to provide sufficient coverage.

[0008] Subsequently, the ion beam is directed to a target terminal station that fixes the target workpiece. Ions within the ion beam are implanted into the target workpiece; this is ion implantation. A key characteristic of ion implantation is the presence of a uniform ion flux angular distribution on the surface of the target workpiece (e.g., a semiconductor wafer). The angular content of the ion beam defines the implantation characteristics through crystal channel effects or masking effects under vertical structures (e.g., photoresist masks or CMOS transistor gates). Non-uniform angular distributions or angular content of the ion beam can lead to uncontrolled and / or unwanted implantation characteristics.

[0009] Angle correction is sometimes used when implementing deflection deceleration lenses to prevent the risk of energy contamination. High-energy contamination can be considered as the presence of ions with undesirable energies (typically higher than desired energies) leading to the placement of inappropriate dopants in the workpiece, which can further result in unwanted device performance or even device damage. Summary of the Invention

[0010] Therefore, the present invention provides an ion implantation system and method for minimizing the angular distribution (e.g., divergence) of the ion beam, for example when tunneling through a crystal structure in a workpiece. Thus, the disclosed system and method enable accurate and rapid adjustment of the ion beam, wherein a tight angular distribution of the ion beam can be achieved through a removable slit at the front focal point of the last ion beam focusing element in the beam delivery system.

[0011] Accordingly, a brief summary of the invention is presented below to provide a basic understanding of some aspects of the invention. This summary is not a broad overview of the invention. It is not intended to indicate key or essential elements of the invention, nor is it intended to describe the scope of the invention. Its purpose is to present some of the concepts of the invention in a simplified form as a prelude to the detailed embodiments presented later.

[0012] The ion implantation system has an ion source configured to form an ion beam. A quality analyzer performs quality analysis on the ion beam, a scanning element scans the ion beam in the horizontal direction, and a parallelizing lens converts the fan-shaped, scanned beam into a parallel-moving scanning ion beam. The present invention recognizes that, for some applications, it may be advantageous to have a highly aligned incident angle across the entire workpiece, while also having a very tight angular distribution, compared to the average or calculated average incident angle across the entire workpiece. Therefore, a slit device is positioned at one or more of the horizontal or vertical front focal points of the parallelizing lens. Optimal beam transmission through the slit device is obtained by adjusting or otherwise controlling the beam focusing lens (e.g., a quadrupole lens) upstream of the scanning element, further achieving a minimal horizontal and / or vertical angular distribution of the ion beam on the workpiece.

[0013] According to one exemplary aspect of the invention, an ion implantation system for implanting ions into a workpiece is provided. For example, the ion implantation system includes an ion source configured to generate an ion beam and a quality analyzer configured to perform quality analysis on the ion beam. For example, a scanning element is configured to scan the ion beam in a horizontal direction, wherein the ion beam has a focal point in each of the horizontal and vertical directions. For example, a slit device has an orifice selectively disposed downstream of the scanning element at one or more corresponding focal points in the horizontal and vertical directions of the ion beam. Furthermore, a parallelizing optics is disposed downstream of the slit device and configured to parallelize the ion beam, thereby minimizing the angular distribution in one or more of the horizontal and vertical directions.

[0014] In one example, the ion beam includes a pencil beam or a dot beam. In another example, the slit device includes a plate in which the orifice is defined. For example, translational devices may be further provided and configured to selectively position the plate, e.g., relative to the ion beam. For example, the transfer device may include a rotational device configured to selectively rotate the plate in and out of the path of the ion beam. In another example, the transfer device includes a linear transfer device configured to selectively linearly translate the plate in and out of the path of the ion beam. For example, a scanning element is configured to provide a scanned beam that radiates in a fan shape.

[0015] In another example, a quadrupole lens is provided upstream of the scanning element, which is configured to provide an angular distribution of the ion beam in both the horizontal and vertical directions. A controller is further provided and configured to control the position of one or more of the orifices of the scanning mechanism, the quadrupole lens, and the slit device to maximize the beam current of the ion beam and minimize the angular distribution of the ion beam on 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 parallelizing optics to maximize the beam current of the ion beam and minimize the angular distribution of the ion beam on the workpiece.

[0016] According to another exemplary aspect of the invention, an ion implantation system is provided, wherein the ion implantation system includes an ion source configured to generate an ion beam, a quality analyzer configured to perform quality analysis on the ion beam, and a scanning element configured to scan the ion beam in a horizontal direction, wherein the ion beam has focal points in the horizontal and vertical directions, respectively. A parallelizing optics device is disposed downstream of a slit device and configured to parallelize the ion beam, thereby defining one or more of a vertical focal point and a horizontal focal point upstream of the parallelizing optics device, thereby minimizing the angular distribution in one or more of the horizontal and vertical directions. Furthermore, a slit device having an aperture is selectively disposed at one or more of the scanning apex of the scanning element and the vertical focal point of the ion beam.

[0017] For example, the slit device includes a plate in which the orifice is defined. The transfer device may be further configured to selectively position the plate. For example, the transfer device may include a rotating device configured to selectively rotate the plate into and out of the path of the ion beam. In an alternative example, the transfer device includes a linear transfer device configured to selectively linearly translate the plate into and out of the path of the ion beam.

[0018] In another example, a quadrupole lens is positioned upstream of the slit device, wherein the quadrupole lens is configured to provide horizontal and vertical focusing at the orifice 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 the position of one or more of the quadrupole lens, the parallelizing optics, and the orifice of the slit device to maximize the beam current of the ion beam and minimize the angular distribution of the ion beam on the workpiece.

[0019] According to another aspect of the invention, a method for minimizing the angular distribution of an ion beam is provided. For example, the method includes focusing the ion beam at 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 the beam current of the ion beam and minimize the angular distribution of the ion beam on a workpiece downstream of the corrector magnet. For example, the quadrupole lens is controlled to independently change the focal point to maximize the transmission of the ion beam through the slit.

[0020] Therefore, in order to achieve the foregoing and related objectives, the present invention includes the features fully described below and particularly pointed out in the claims. The following detailed description and accompanying drawings illustrate certain exemplary embodiments of the invention. However, these embodiments are merely some of the various ways in which the principles of the invention can be employed. Other objects, advantages, and novel features of the invention will become apparent when the following detailed description of the invention is understood in conjunction with the accompanying drawings. Attached Figure Description

[0021] Figure 1 An example ion implantation system according to one aspect of the present invention is shown.

[0022] Figure 2 A schematic diagram of a finite beam angle distribution according to one aspect of the present invention is shown.

[0023] Figure 3 This is a schematic diagram of a scanned ion beam showing the injection angle according to one aspect of the present invention.

[0024] Figure 4 This is a schematic diagram of a scanned ion beam according to one aspect of the invention, showing the injection angle incorporated into a slit for horizontal divergence.

[0025] Figure 5 This is a schematic diagram of a scanned ion beam according to one aspect of the invention, showing a vertical diverging slit.

[0026] Figure 6A This is a simplified perspective view of an example vertical diverging slit device for controlling the injection angle according to one aspect of the present invention.

[0027] Figure 6B This is a top view of an example vertical diverging slit device according to another aspect of the invention.

[0028] Figure 6C This is another aspect of the invention. Figure 6B A side view of an example vertical diverging slit device. Detailed Implementation

[0029] This invention provides an ion implantation system and method for controlling (e.g., minimizing) the angular distribution (e.g., divergence) of an ion beam, for example when tunneling through a crystal structure in a workpiece. Furthermore, by providing a removable slit at the pre-focal point of the last focusing element downstream in the ion beam transport system, a system and method are provided for precisely and rapidly adjusting the ion beam to achieve a tight angular distribution.

[0030] Accordingly, the invention is now described with reference to the accompanying drawings, wherein the same reference numerals may be used throughout to refer to the same elements. It should be understood that the description of these aspects is merely illustrative and should not be construed as limiting. In the following description, numerous specific details are set forth for illustrative purposes to provide a full understanding of the invention. It will be apparent to those skilled in the art that the invention can be practiced without these specific details. Furthermore, the scope of the invention is not limited to the embodiments or examples described below with reference to the accompanying drawings, but only to the appended claims and their equivalents.

[0031] It should also be noted that the accompanying drawings are provided to illustrate some aspects of embodiments of this disclosure and should therefore be considered illustrative only. In particular, the elements shown in the drawings are not necessarily drawn to scale, and the arrangement of the various elements in the drawings is intended to provide a clear understanding of the respective embodiments and should not be construed as necessarily representing the actual relative positions of the various components in an embodiment according to the invention. Furthermore, unless otherwise specifically stated, features of the various embodiments and examples described herein can be combined with each other.

[0032] 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 units or functional units shown in the figures or described herein may also be achieved through indirect connection or coupling. Furthermore, it should be understood that functional blocks or units shown in the figures may be implemented as separate features or circuits in one embodiment, while in another embodiment they may be implemented wholly or alternatively in a common feature or circuit. For example, several functional blocks may be implemented as software running on a common processor such as a signal processor. It should also be understood that, unless otherwise stated, any connection described in the following specification as wired may also be implemented as wireless connectivity.

[0033] The present invention recognizes that, in order to better tunnel through crystal lattice structures, especially at high energies, the ion beam should be angled to the crystal lattice structure of the workpiece. Various examples of tunneling concepts and ion implantation systems are provided in co-owned U.S. Patent 9,711,328 to Satoh, the entire contents of which are incorporated herein by reference.

[0034] The present invention also recognizes that such alignment of the ion beam includes not only the average or calculated average angle of the ion beam relative to the lattice, but also its distribution.

[0035] For example, for extremely high-energy arsenic (As) implantation greater than about 10 MeV, the ions within the ion beam should have a tight angular distribution in order to provide the required tunneling depth profile, such as an angular distribution of less than about 0.1 degrees in standard deviation.

[0036] Traditionally, controlling the injection angle mainly focuses on controlling the average incident angle of the entire ion beam, with less attention paid to the ion beam distribution. However, with the increasing popularity of tunneling injection, the issue of injection angle distribution and how to reliably obtain ion beams with very small angle distributions has become more important.

[0037] Adjusting an ion beam to provide a very small angular distribution is typically a tedious trial-and-error process; that is, repeatedly and almost blindly changing parameters, measuring the resulting angular distribution of the ion beam, and continuing to modify the parameters until the desired distribution is obtained. This invention provides a rapid solution to the conventional, slow, and unreliable adjustment process for minimizing the angular distribution. This invention provides a basis for adjusting vertical beam divergence in ion implantation systems, as exemplified in the non-limiting example, of the Purion XE / VXE / XEmax manufactured by Axcelis Technologies, Inc., Beverly, Massachusetts.

[0038] To better understand the invention, according to various exemplary aspects of the invention, Figure 1 An ion implantation system 100 is shown. The ion implantation system 100 is presented for illustrative purposes, and it should be understood that aspects of the invention are not limited to the described ion implantation system, and other suitable ion implantation systems with different configurations may also be employed.

[0039] The illustrated ion implantation system 100 includes a terminal 102, a beam assembly 104, and a terminal station 106. For example, the terminal 102 includes an ion source 108 powered by a high-voltage power supply 110, which generates and guides an ion beam 112 through the beam assembly 104 and ultimately to the terminal station 106. The ion beam 112 can be in the form of a dot beam, pencil beam, ribbon beam, or any other beam shape. The beam assembly 104 also includes a beam guide 114 and a mass analyzer 116, wherein a dipole magnetic field is established to allow only ions with an appropriate charge-to-mass ratio to pass through an aperture 118 at the exit end of the beam guide 114 to define a mass-analyzed ion beam 135, which is guided toward a workpiece 120 (e.g., a semiconductor wafer, display panel, etc.) disposed in the terminal station 106.

[0040] According to one example, an ion beam scanning system 122 (collectively referred to as a “scanner” or “scanning element”), such as an electrostatic or electromagnetic scanner, is configured to scan a workpiece 120 with an ion beam 112 in at least a first direction 123 (e.g., the + / -y- direction, also referred to as a first scan path or a “fast scan” axis, path, or direction), wherein a strip-shaped ion beam or a scanned ion beam 124 (e.g., a fan-shaped scanned ion beam) is defined. Furthermore, in this example, a workpiece scanning system 126 is provided, wherein the workpiece scanning mechanism is configured to selectively scan the workpiece 120 with the ion beam 112 in at least a second direction 125 (e.g., the + / -x direction, also referred to as a second scan path or a “slow scan” axis, path, or direction). For example, the ion beam scanning system 122 and the workpiece scanning system 126 may be provided individually or in combination to provide the desired scanning of the workpiece with the ion beam 112. In another example, an electrostatically scanned ion beam 112 is used in a first direction 123, wherein a scanned ion beam 124 is generated, and the workpiece 120 is mechanically scanned in a second direction 125 by the scanned ion beam 124.

[0041] This combination of electrostatic and mechanical scanning of the ion beam 112 and the workpiece 120 forms a so-called "hybrid scanning". The invention applies to all combinations of scanning of the workpiece 120 by the ion beam 112, or vice versa. Furthermore, a controller 130 is provided, configured to control one or more components of the ion implantation system 100.

[0042] According to one exemplary aspect of the invention, a beam measurement system 150 is further provided.

[0043] For example, beam measurement system 150 is configured to determine one or more characteristics associated with ion beam 112. Systems and methods for measuring the incident angle of ions on workpiece 120 and calibrating the incident angle of ions on workpiece crystal planes have been provided in the so-called "PurionXE" ion implantation system and in U.S. Patent 7,361,914, co-owned by Robert D. Rathmell et al., the entire contents of which are incorporated herein by reference.

[0044] In this way, the mass analyzer 116 allows those ion species in the ion beam 112 with the desired charge-to-mass ratio to pass through, defining the mass-analyzed ion beam 135 exiting the orifice 118. Although not shown, for example, the mass-analyzed ion beam 135 is accelerated to the required energy before entering the scanning element 122 and further focused by a beam-focusing lens (e.g., a quadrupole lens). The scanned ion beam 124 then passes through a parallelizer 160 (e.g., a parallelizer / corrector component, also referred to as a "corrector magnet"), which in the illustrated example includes two dipole magnets 162A, 162B.

[0045] For example, dipole magnets 162A and 162B are essentially trapezoidal and mirror images of each other, so that the scanned ion beam 124 is bent into an essentially S-shape. In other words, dipole magnets 162A and 162B have equal angles and radii and opposite directions of curvature.

[0046] For example, the parallelizer 160 alters the beam path of the scanned ion beam 124 regardless of the scan angle, ensuring that the mass-analyzed beam travels parallel to the beam axis. Therefore, the injection angle is uniform across the entire workpiece 120. In one example, one or more parallelizers 160 also function as deflectors, causing neutral particles generated upstream of the parallelizer to deviate from their nominal paths, thus reducing their probability of reaching the terminal station 106 and workpiece 120 to near zero.

[0047] It should be understood that one or more so-called corrector magnets or parallelizers 160 may include any suitable number of electrodes or magnets configured and biased to focus, bend, deflect, converge, diverge, scan, parallelize, and / or purify the ion beam 112. The terminal station 106 then receives the quality-analyzed ion beam 135, which is guided toward the workpiece 120. It should be understood that different types of terminal stations 106 may be employed in the ion implantation system 100. For example, a "batch" type terminal station may simultaneously support multiple workpieces 120 on a rotating support structure, wherein the workpieces rotate through the path of the ion beam 112 until all workpieces are fully implanted. On the other hand, a "serial" type terminal station supports a single workpiece 120 along the beam path for implantation, wherein multiple workpieces are implanted one at a time in a serial manner, each workpiece being fully implanted before the next workpiece is implanted. In the hybrid system, the workpiece 120 can be mechanically translated in a first direction (e.g., along the y-axis, also known as slow scan or vertical direction) and scanned in a second direction (e.g., along the x-axis, also known as fast scan or horizontal direction) to apply the ion beam 112 over the entire workpiece.

[0048] Figure 1 The terminal station 106 in the illustrated example is a "serial" terminal station that supports a single workpiece along the beam path for implantation. Terminal station 106 may further include a beam measurement system 150 located near workpiece 120 to facilitate calibration measurements prior to the implantation operation. During calibration, the ion beam 112 passes through the beam measurement system 150. For example, the beam measurement system 150 includes one or more profilometers, which may be stationary or continuously passing through a profilometer path to measure the profile of the ion beam 112 (e.g., scanned or unscanned dot or pencil beam).

[0049] Ions within ion beam 112 typically travel in the same direction, exhibiting a degree of distribution (e.g., divergence) around the average angle of the angular distribution. Therefore, the present invention envisions a constant incident angle (i.e., the average angle of the distribution) across the entire surface of workpiece 120 during ion implantation as an important consideration.

[0050] Furthermore, for example, the fidelity or tightness of the ion beam angle distribution defines the implantation characteristics through crystal channel effects or masking effects under vertical structures (such as photoresist masks or CMOS transistor gates). For example, an uncontrolled angle distribution of ion beam 112 results in uncontrolled and unwanted implantation characteristics.

[0051] Therefore, the incident angle (average angle of the distribution) and angular distribution of the ion beam 112 are measured with high precision using various beam diagnostic equipment, some of which have been discussed above. The measurement data can then be used in angle correction methods. Once correction is applied, the measurement and adjustment of the beam angle are repeated until the desired beam angle characteristics, average angle, and tight distribution are obtained.

[0052] For example, in some injection systems, Figure 1 One or more corrector magnets or parallelizers 160 are used to convert a horizontally fan-shaped beam into a parallel-shifted scanned beam. For example... Figure 2 As shown, the parallelization function or optics can be considered as a positive focusing lens system 200 including the parallelization optics 202 (also referred to as the parallelization lens). For example, the parallelization optics 202 may include or be composed of Figure 1 The corrector magnet or parallelizer 160 comprises, for example, a parallelizing optics 202 configured to obtain a substantially constant "average" injection angle across the width of the workpiece 120. For example, the front focal point 204 or positive lens of the corrector magnet 160 is located at the scanning vertex 154 of the scanner or scanning element 122. Figure 2 In the ideal case, each row 206 of the ion beam 112 represents the ion beam 112, which has a “zero” angular distribution, or in other words, in the horizontal direction (e.g., Figure 2 The substantially small angular distribution 208 of the ion beam 112 in the x direction shown.

[0053] Figure 3 An example is shown where the incident ion beam 209 (e.g., the mass-analyzed ion beam 135) has a finite angular distribution 210. In this case, when the incident ion beam 209 with the finite angular distribution 210 is focused to the same scan vertex position (e.g., ... Figure 3When the cone 212 emanating from the scanning vertex 154 reaches the workpiece 120, the final ion beam 213 also has a finite angular distribution 210. The degree of angular distribution of the final ion beam 213 depends on the degree to which the incident ion beam 209 is focused at the scanning vertex 154.

[0054] According to the present invention, Figure 4 An example is shown in which a slit 214 (e.g., a slit defined in a retractable plate with an orifice configured to enable operation of the scanning element 122) is positioned at the scanning vertex 154, thereby adjusting or otherwise controlling various lenses upstream of the scanning element to focus or otherwise provide maximum emission of the incident ion beam 209 through the slit. Thus, the ion beam 112 arrives at the workpiece 120 with a minimum angular distribution 216. According to the invention, Figure 4 Therefore, a system 218 with minimized horizontal angular distribution is shown. Although it is understood that in the design... Figure 4 Various technical problems exist in the slit 214 shown, such as being retractable at the scanning vertex 154 while providing operation of the scanning element 122 in a high-voltage environment during normal operation of the ion implantation system. However, the present invention envisions such a system providing the required angular distribution of the ion beam 112 to be minimized.

[0055] Figure 5 An example of a system 220 that minimizes the vertical angle distribution is shown. For example, in the vertical direction (e.g., in...) Figure 5 (As shown in the y-direction), the corrector magnet 160 is configured to provide strong positive focusing power, thereby allowing the corrector magnet to be used to minimize the vertical beam angle distribution 222 using a principle similar to that used in the horizontal direction, as discussed above. Therefore, the present invention provides a vertical divergence slit (VDS) device 224 (also referred to as a retractable slit device) for minimizing the vertical beam angle distribution 222. In one example, the VDS device 224 is immediately following the exit 226 of the scanning element 122, and it is also close in the vertical direction to the front focal point of the lens of the corrector magnet 160. For example, the focusing capability of the corrector magnet 160 (e.g., the so-called "S-curve") is strong enough that the slit 214 of the VDS device 224 can be positioned at the exit 226 of the scanning element 122 at its focal point 228. For example, the VDS device 224 can be selectively removed 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 indicated by arrow 229 in one example. For example, the slit 214 of the VDS device 224 is configured to be selectively positioned, translated, and / or rotated along or about any one of the x-axis, y-axis, or z-axis.

[0056] It should be noted that while this paper specifically discusses particular ion implantation, other ion implantation systems, for example, can utilize similar systems as discussed above to minimize the angular distribution of the final beam in either the horizontal or vertical direction, thereby providing a slit at the front focal point of the final positive lens in the corresponding horizontal or vertical direction.

[0057] In one example, due to the stronger vertical focal length, the VDS device 224 is provided after the scanning element 122, and therefore, the slit 214 is located closer to the corrector magnet 160.

[0058] For example, the ion beam 112 can thus be adjusted before or after the scanning element 122, for example via a quadrupole lens (not shown), thereby removing the slit 214 after adjustment, and thus allowing subsequent ion implantation into the workpiece 120. During adjustment, the slit 214 is positioned along the beamline, and the upstream lens (not shown) can be adjusted and focused point-by-point. The beam current of the ion beam 112 can then be measured so that transmission through the slit 214 is optimized (e.g., generating a maximized beam current), thereby providing an indication that the ion beam passing through the slit is very small. Therefore, the present invention provides an auxiliary tool for angular distribution control adjustment.

[0059] Figures 6A-6C Another example of a vertical angle distribution minimization system 300 according to various aspects of the present invention is shown. As an overview, Figure 6A A vertical angle distribution minimization system 300 is illustrated, in which an ion beam 112 passes through a quadrupole lens 302 and is subsequently scanned in the horizontal direction (e.g., the x-direction) by a scanning element 122. For example, the VDS device 224 is selectively positioned (e.g., indicated by arrow 229) such that the horizontal dimension 304 and vertical dimension 306 of the slit 214 primarily limit only the vertical height of the scanned ion beam 124 (e.g., in the y-direction), while allowing the ion beam 112 to pass through the entire scan width in the horizontal direction. For example, the scan vertex 154 coincides with the horizontal front focal point 308 of the parallelizing optics 202.

[0060] Figure 6B It shows Figure 6AA top view of the system 300 with minimized vertical angular distribution, labeled 310, shows the scanned ion beam 124 not obstructed horizontally by the slit 214 of the VDS device 224. The horizontal curvature point of the scan vertex 154, or scan element 122, is located at the horizontal front focal point 308 of the parallelizing optics 202. For illustrative purposes, the parallelizing optics 202 is described as a simple positive focusing lens; however, other lens systems are also conceivable. For example, a quadrupole lens 302 focuses the ion beam 112 at the scan vertex 154, thereby resulting in a final ion beam 213 exiting the parallelizing optics 202 that is horizontally parallel and has a minimal angular distribution.

[0061] Figure 6C Show Figure 6A A side view of the system 300 with minimized vertical angular distribution, labeled 312, shows the slit 214 of the VDS device 224 positioned (e.g., shown as arrow 229) at the vertical front focal point 314 of the parallelizing optics 202, where the quadrupole lens 302 vertically focuses the ion beam 112 at the VDS slit. It should be understood that, for example, the VDS device 224 may include a transfer device 316 comprising one or more linear actuators, rotary actuators, gears, linkages, and / or other mechanisms operable to be coupled to a plate 318, wherein the slit 214 is defined in the plate 318, and one or more controllers or other control mechanisms, wherein the VDS device is configured to selectively position the slit 214 at the vertical front focal point 314 and scan the vertex 154. Thus, the final ion beam 213 emanating from the parallelizing optics 202 is advantageously vertically parallel while also having a minimum angular distribution in the vertical direction, as described above. If necessary, the VDS device 224 can be further removed from the path of the ion beam 112.

[0062] Therefore, this invention offers advantages over conventional iterative trial-and-error processes, enabling faster and easier real-time adjustments to ion implantation systems.

[0063] Although the invention has been described and illustrated with respect to one or more embodiments, changes and / or modifications may be made to the illustrated examples without departing from the spirit and scope of the appended claims. In particular, for the various functions performed by the aforementioned components or structures (blocks, units, engines, components, devices, circuits, systems, etc.), unless otherwise stated, the terminology used to describe such components (including references to "device") is intended to correspond to any component or structure that performs the specified function of the aforementioned components (e.g., functionally equivalent components), even if it is not structurally equivalent to the disclosed structure that performs the functions described in the exemplary embodiments of the invention shown herein.

[0064] Furthermore, while a particular feature of the invention may be disclosed with respect to only one of several embodiments, such features may be combined with one or more other features of other embodiments where they may be desired and advantageous for any given or particular application. The term "exemplary" as used herein refers to an example, not a best or better one. Additionally, the terms "comprising," "including," "having," or variations thereof as used in the detailed description and claims are intended to be similar to the term "comprising."

Claims

1. An ion implantation system for implanting ions into a workpiece, the ion implantation system comprising: an ion source configured to generate 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, wherein the ion beam has a respective focus in the horizontal direction and a vertical direction; a slit device having an aperture selectively disposed downstream of the scanning element at one or more respective foci of the ion beam in the horizontal direction and the vertical direction; and a parallelizing optic disposed downstream of the slit device and configured to parallelize the ion beam, thereby minimizing an angular distribution in one or more of the horizontal direction and the vertical direction.

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 device 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. The ion implantation system of claim 4, wherein, The translation device comprises a rotational device configured to selectively rotate the plate into and out of a path of the ion beam.

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

7. The ion implantation system of claim 1, wherein, The scanning element is configured to define a scanned ion beam that fans out in a sector.

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

9. 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 device, and the parallelizing optic to maximize a beam current of the ion beam and minimize an angular distribution of the ion beam on the workpiece.

10. An ion implantation system for implanting ions into a workpiece, the ion implantation system comprising: an ion source configured to generate 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 from a scan apex; a parallelizing optic disposed downstream of the scanning element and configured to parallelize the ion beam, whereby the parallelizing optic defines one or more of a vertical focus of the ion beam in a vertical direction and a horizontal focus of the ion beam in a horizontal direction, wherein the vertical focus and the horizontal focus are upstream of the parallelizing optic; and a controller configured to control one or more of the ion source, the mass analyzer, the scanning element, the parallelizing optic, and the slit device to maximize a beam current of the ion beam and minimize an angular distribution of the ion beam on the workpiece. ​ A slit device having an aperture selectively disposed at one or more of the scan apex and the vertical focus of the ion beam, thereby minimizing the angular distribution of the ion beam in one or more of the horizontal and vertical directions, wherein the slit is located downstream of the scan apex and upstream of the parallelizing optics.

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

12. The ion implantation system of claim 10, wherein, The slit device 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. The ion implantation system of claim 13, wherein, The translation device comprises a rotational device configured to selectively rotate the plate into and out of the path of the ion beam.

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

16. The ion implantation system of claim 10, wherein, The scan element is configured to provide a scanned ion beam that fans out.

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

18. The ion implantation system of claim 17, further comprising a controller configured to control one or more of the quadrupole lens, the parallelizing optics, 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 on the workpiece.

19. A method for minimizing the angular distribution of an ion beam on a workpiece, the method comprising: focusing the ion beam at a scan apex upstream of a corrector magnet; selectively positioning a slit downstream of the scan apex and upstream of the corrector of the ion beam; and controlling a quadrupole lens upstream of the slit to maximize the beam current of the ion beam and minimize the angular distribution of the ion beam on the workpiece downstream of the corrector magnet.

20. The method of claim 19, wherein, controlling the quadrupole lens to independently vary the scan apex to maximize the transmission of the ion beam through the slit.

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