JPWO2020123063A5 - - Google Patents

Description

Detailed description of the invention

[Reference to related applications]
This application is based on U.S. patent application Ser. Claiming benefits of ``Scanning and Correction Magnet Design''.

[Field of the invention]
FIELD OF THE INVENTION The present invention relates generally to ion implantation systems, and more specifically to improved systems and methods for providing a predetermined uniformity and angular profile of a scanned ion beam.

[Background of the invention]
Ion implanters are conventionally utilized to place specific amounts of dopants or impurities into semiconductor workpieces or wafers. In a typical ion implantation system, a dopant material is ionized to produce an ion beam therein. An ion beam is directed at the surface of a semiconductor wafer to implant ions into the wafer. In the wafer, ions penetrate the surface of the wafer and form regions of desired conductivity in the wafer. For example, ion implantation is particularly used in the manufacture of transistors in semiconductor workpieces. A typical ion implanter includes: an ion source for generating an ion beam; a beamline assembly having a mass spectrometer for directing and/or filtering (e.g., mass resolving) ions within the ion beam; a target chamber containing one or more wafers or workpieces to be processed.

Various types of ion implanters can each vary the dose and energy of the ions to be implanted based on the desired properties to be achieved within the workpiece. For example, high current ion implanters are typically used for high dose implants at low to medium energies, and medium to low current ion implanters are typically used for low dose applications at high energies. Ru.

As device geometries continue to shrink, depthless junction contact regions translate into demands for lower ion beam energies. In addition, the requirement for precise dopant placement places an increasingly stringent requirement on minimizing beam angle variations within the beam and across the substrate surface. For example, in certain applications, implantation with energies down to 300 eV may be desirable, while minimizing energy contamination, maintaining tight control of angular variations within the ion beam and across the workpiece, and , it is desirable to provide high throughput of workpiece processing.

Hybrid scanning beams can provide very good dose uniformity at high throughput. The ion beam is thereby electrically or magnetically scanned across the workpiece. To this end, the workpiece is mechanically translated through the scanning ion beam. However, for low energy implants, the throughput of the workpiece through the system is limited by the size of the ion beam and the large scan amplitude utilized to provide complete overscanning of the workpiece by the ion beam.

[Summary of the invention]
The present disclosure provides systems and methods that increase the efficiency of ion implantation systems over conventional systems. The systems and methods advantageously provide improved designs of one or more of the scanning magnets and correction magnets. The following presents a simplified summary of the invention to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention and is intended to neither identify key or critical elements of the invention nor delineate the scope of the invention. Rather, the purpose of this summary is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.

The present disclosure provides systems and methods for providing non-uniform flux profiles of scanned ion beams. According to one example aspect of the present disclosure, an ion implantation system is provided. In such ion implantation systems, the ion beam is configured to scan across the surface of the workpiece (across the surface of the workpiece) at an ion beam scanning frequency, such that the ion beam is (also called a scanned ribbon). For example, a spot ion beam is formed and provided to a scanner, and a scanning waveform with a time-varying potential is applied to the scanner. The ion beam is scanned by a scanner across a scan path generally defining a scanned ion beam comprised of a plurality of beamlets. The scanning beam then passes through a correction device. The correction device is configured to direct the scanned ion beam toward the workpiece at a substantially constant angle of incidence across the workpiece. The correction device further comprises a plurality of magnetic poles configured to provide a non-uniform flux profile of the scanned ion beam at the workpiece.

The following description and accompanying drawings set forth in detail certain exemplary aspects and implementations of the invention. These are just a few examples of the various ways in which the principles of the invention can be used.

[Brief explanation of the drawing]
FIG. 1A is an embodiment of an ion implantation system having a scanner, a correction device, and a dosimetry system in accordance with various aspects of the present disclosure.

FIG. 1B is an embodiment of the scanner and several scanned ion beams of FIG. 1A.

FIG. 1C is one embodiment of a triangular scanning current waveform in the scanner of FIGS. 1A and 1B.

FIG. 1D is a perspective view of one scanned ion beam impinging on a workpiece at several separate points in time in the system of FIG. 1A.

FIG. 2 is a perspective view of the magnetic pole and beam guide of a conventional correction device.

FIG. 3A is a schematic diagram of an ideal ion beam passing through an ideal scanner and correction device.

FIG. 3B is a graph showing an ideal beam flux profile using the ideal scanner and correction device of FIG. 3A.

FIG. 3C is a graph showing an exemplary flux profile generated using a non-uniform triangular current waveform.

FIG. 4 is a perspective view of a magnetic pole and beam guide of a correction device according to various aspects of the present disclosure.

FIG. 5A is a schematic diagram of an ion beam passing through a scanner and correction device in accordance with various aspects of the present disclosure.

FIG. 5B is a graph illustrating a non-uniform beam flux profile using the scanner and correction apparatus of FIG. 5A.

FIG. 6A is a schematic illustration of a scanned ion beam passing through another scanner and another correction device in accordance with various aspects of the present disclosure.

FIG. 6B is a graph illustrating a non-uniform beam flux profile using the scanner and correction apparatus of FIG. 6A.

FIG. 7 is a chart illustrating first and second functions relating scan angle to scan current applied to a scanner in accordance with various aspects of the present disclosure.

FIG. 8 is a chart illustrating various magnetic pole designs in accordance with various aspects of the present disclosure.

FIG. 9 is a flow diagram illustrating a method of providing a non-uniform flux profile to a workpiece in accordance with various aspects of the present disclosure.

[Detailed description of the invention]
The invention will be explained with reference to the drawings. In the drawings, like reference numbers are used throughout to refer to like elements. Additionally, the illustrated structures are not necessarily drawn to scale.

FIG. 1A shows an exemplary ion implantation system 10 that includes a terminal 12, a beamline assembly 14, and an end station 16. The ion implantation system is configured to implant ions into a workpiece 18 located at an end station. The terminal 12 includes, for example, an ion source 20 powered by a high voltage power supply 22. The ion source generates and directs an ion beam 24 to beamline assembly 14 . For example, ions generated within ion source 20 are extracted to form ion beam 24 . The ion beam is thereby directed along beam path 26 within beam line assembly 14 toward end station 16 .

Beamline assembly 14 includes, for example, a beam guide 28, a mass analyzer 30, a resolving aperture 34, a scanning system 36, and a correction device 38. A dipole magnetic field is installed within the mass analyzer 30 and only ions of the appropriate charge-to-mass ratio pass through the resolving aperture 34. Scanning system 36 may include, for example, an electrostatic scanning system or a magnetic scanning system. The scanning system 36 illustrated in the exemplary embodiment of FIG. 1A shows a magnetic scanner 40 having a power source 42 coupled to a scanner coil 44. Scanner 40 is positioned along beam path 26 and receives ion beam 24 after it has been mass analyzed by mass analyzer 30 . Here, the scanner of FIG. 1A magnetically scans the ion beam to generally define a scanned ion beam 46 (eg, also referred to as a "scanning ribbon"). Correction device 38 directs scanned ion beam 46 toward end station 16 such that, for example, scanned ion beam 46 impinges on workpiece 18 at a substantially constant angle of incidence across the workpiece. For example, scanning of ion beam 24 to form scanned ion beam 46 is controlled by control system 48 . For example, control system 48 controls the power provided to scanner coil 44 . This causes the ion beam 24 to be magnetically scanned over the entire workpiece 18 .

Ion implantation system 10 may further include various beam forming and shaping structures (not shown) extending between ion source 20 and end station 16. The forming and shaping structures maintain and couple the ion beam 24 as it is transported to the workpiece 18 within the end station 16. This path through which the ion beam 24 is traversed and maintained is typically kept under vacuum, reducing the possibility that the ions will be deflected from the beam path 26 by collisions with air molecules.

Ion implantation system 10 may use different types of end stations 16. For example, a "batch" end station may support multiple workpieces 18 simultaneously, eg, on a rotating support structure. In a batch end station, workpieces are rotated through the path of the ion beam until all workpieces have been implanted. A "continuous" end station, on the other hand, supports a single workpiece 18 along the beam path for implantation. In a continuous end station, multiple workpieces are implanted one at a time in a continuous manner, with each workpiece completing its implantation before implantation of the next workpiece begins.

The illustrated end station 16 supports a single workpiece 18 (e.g., a semiconductor wafer, display panel, or other workpiece into which ions from beam 24 are implanted) along the beam path for implantation. It is a "continuous" end station. At the end station 16, a dosimetry system 50 is positioned near the workpiece to take calibration measurements prior to the injection operation. During calibration, ion beam 24 passes through dosimetry system 50 . Dosimetry system 50 includes, for example, one or more profilers 52 configured to traverse a profiler path 54 to measure the profile of ion beam 24 (eg, scanned ion beam 46). Correction device 38 directs scanned ion beam 46 toward end station 16 such that the scanned beam impinges one or more profilers 52 of dosimetry system 50 at a substantially constant angle of incidence.

Profiler path 54 is disposed, for example, along an injection plane relative to surface 56 of workpiece 18. One or more profilers 52 include, for example, a current density sensor 58 (eg, a Faraday cup) for measuring the current density of the scanned ion beam 46. Current density sensor 58 moves generally perpendicular to scanned ion beam 46 and traverses the width of the scan path. Dosimetry system 50 is further operably connected to and receives command signals from control system 48, for example, to perform measurement aspects of the disclosed calibration methods as further described herein. and provide measurements to control system 48 .

According to one exemplary aspect, scanner 36 receives ion beam 24 and a current waveform applied to scanner coil 44 by power supply 42 moves ion beam 24 back and forth in the X direction (e.g., scan direction). It operates to scan and spread the ion beam into an elongated "scanned ribbon" beam (eg, scanned ion beam 46). This elongated "scanning ribbon" beam has an effective width in the X direction that is at least as wide as or wider than the target workpiece 18. Scanning ion beam 46 then passes through correction device 38 . Correction device 38 directs scanned ion beam 46 toward end station 16 substantially parallel to the Z direction (eg, substantially perpendicular to surface 56 of workpiece 18).

In an electrostatic scanning system (not shown), a power source(s) is connected to a plurality of electrodes spaced around the beam. The electric field between the electrodes is further adjusted to scan the ion beam. For purposes of this disclosure, all different types of scanning systems 36 are considered, and the magnetic field system of FIG. 1A is one illustrative example of such a scanning system.

An exemplary magnetic field version of scanning system 36 is further illustrated in FIG. 1B. In FIG. 1B, power supply 42 provides alternating current to coil 44, as shown in waveform 60 of FIG. 1C. Time-varying waveform 60 (eg, a triangular waveform) produces a time-varying magnetic field across beam path 26. This time-varying magnetic field causes the ion beam 24 to be bent or deflected (eg, scanned) along the scan direction (eg, the X direction in FIGS. 1A, 1B, and 2B-2F).

When the scanning magnetic field is directed out of the page, as at times "e" and "g" in FIG. 1C, the positively charged ions of the ion beam 24 experience a lateral force in the negative direction of the X-axis. When current I is zero, such as at time "d" in FIG. 1C, beam 24 passes through scanner 40 unchanged. When the magnetic field is directed into the page (eg, times "a" and "c" in FIG. 1C), the positively charged ions of the ion beam 24 experience a lateral force in the positive X-axis direction.

FIG. 1B shows the deflection associated with scanner beam 46 that occurs as ion beam 24 passes through scanner 40 at several discrete points during scanning prior to entering corrector 38 of FIG. 1A. FIG. 1D shows a scanning ion beam 46 (eg, ion beams 24a-24g) impinging on workpiece 18 at corresponding times "a" to "g" shown in FIG. 1C. The scanned collimated ion beam 24a of FIG. 1D corresponds to the applied electrode voltage or current at time "a" of FIG. 1C. Ion beams 24b-24g are then shown in FIG. 1D for scan voltages or currents at corresponding times "b" to "g" in FIG. 1C for a single generally horizontal scan across workpiece 18 in the X direction. ing.

As shown in FIG. 1A, the translation device 62 (e.g., a mechanical actuator) moves the workpiece 18 at the same time that the scanner 40 scans the ion beam 24 back and forth in the X direction (e.g., fast scan direction). is translated in the Y direction (for example, in the slow scan direction). This causes ion beam 24 to be applied onto surface 56 of workpiece 18 .

The present disclosure shows that in an idealized implanter, a triangular wave in voltage or current applied to the scanner 40 produces a triangular wave in the beam angle, and after the correction device 38, a uniform scanning ribbon beam 46 (e.g., a uniform flux Understand that generating a profile) However, it is difficult to realize such an ideal injection device for various reasons. Additionally, in some cases it may be beneficial to vary the dose profile on the workpiece 18 to achieve different results.

In particular, the current waveform from power supply 42 to scanner 40 can be varied to produce a desired dose profile on workpiece 18. In some cases it is desirable for the dose profile to be uniform, although other non-uniform profiles are sometimes desirable. The particular current waveform that produces the desired flux profile generally depends, for example, on how the beam current and shape of the ion beam 24 changes as the ion beam 24 is scanned across the workpiece 18. do. Ion beams 24 having the smallest size may have little or no change in shape over the scan. This produces a waveform in which the ion beam 24 has a minimum amplitude and minimal distortion or deviation from the nominal triangular wave. Accordingly, such a minimally sized ion beam 24 is, for example, the most efficient and the least demanding on the scanner 40.

To maintain a small size ion beam 24 and minimize space charge blowup, for example, magnetic scanners and correction devices may be Used in high current beamlines as opposed to electrical scanners and correction devices. For example, an S-shaped magnet may be utilized in correction device 38 to maintain the ion beam 24 shape generally constant across the scan. This makes the path length of the ion beam more similar across the scan compared to the use of a single-bend magnet or electrostatic collimating lens in the corrector.

For example, FIG. 2 shows a conventional configuration of magnetic poles 70A, 70B associated with respective inlets 72 and outlets 74 of a conventional corrector 75. For simplicity, the magnet yoke and coils are not shown in FIG. This is because they are generally not very important in defining the beam trajectory. FIG. 3A is a further diagram of a conventional correction device 75. A conventional correction device 75 may be placed downstream of the scanner 40 such that the various trajectory paths 26 of the ion beams 24a-24g have different scan angles θa-θg upon exiting the scanner. There is. Here, these scanning angles θa-θg are uniformly spaced apart over time. If an "ideal" ion beam (e.g., a "point" ion beam) is scanned completely across the workpiece using a triangular wave (as shown in FIG. 1C), as shown in FIG. 3B, As such, a substantially uniform flux profile 76 is produced across the workpiece 18. For example, the substantially uniform flux profile 76 of FIG. 3B has an average flux Ψ ₀ resulting from a substantially uniform scan and conventional correction device 75. However, in reality, in contrast to the "ideal" ion beam described above, "real" ion beams change shape, size, and current as the beam is scanned, creating a triangular current waveform. The actual flux profile 77 generated in is not uniform, as shown in FIG. 3C.

However, increasing the beam current of the ion beam 24 makes it more difficult to reduce the size of the ion beam and maintain constant characteristics. For example, at larger beam sizes, differences in the shape of the ion beam 24 across scans become more relevant if the shape of the ion beam affects a larger portion of the workpiece 18. For example, when using the nominal triangular waveform 60 of FIG. 1C, a reduction in beam flux is seen at the edge 78 of the workpiece 18. As a result, uniformity correction by scanning waveform 60 becomes more difficult because a more highly modified waveform is introduced in an attempt to provide a uniform flux profile on workpiece 18. Such uniformity corrections may further reduce the throughput of workpiece 18 through system 10 of FIG. 1A. This is because the ion beam 24 spends more time at the edge 78 of the workpiece implanting a smaller fraction of the workpiece.

Thus, in accordance with the present disclosure, increased throughput of workpiece 18 through system 10 is achieved, at least in part, by reducing scanner 40 and/or correction device 38 from the nominal triangular waveform 60 and ideal point beam of FIG. 1C. This can be accomplished by configuring the ion beam to maintain parallelism in the ion beam 24 while creating a non-uniform flux profile across the workpiece 18 when using the ion beam. Next, the non-uniform flux profile is corrected to be uniform or to have a predetermined non-uniform profile, for example by adjusting the waveform applied to the scanner 40. FIG. 5A illustrates an example of a correction device 38 in accordance with various aspects of the present disclosure. The magnetic poles 80A, 80B of the corrector are configured to provide a non-uniform flux profile of the ion beam 24 through the inlet 82 and outlet 84.

For example, various shapes of the magnetic poles 80A, 80B of the correction device 38 associated with the scanner 40 of FIG. 5A can advantageously provide a non-uniform flux profile 86, as illustrated in FIG. 5B. This provides a greater amount of beam flux toward the edges 78 of the workpiece 18 than near the center 88. Note that the present disclosure may be applied to any correction device 38, whether the correction device 38 includes a single magnet or multiple magnets in an S-shaped configuration. Additionally, it is noted that the scanner 40 and any magnets associated therewith may be bipolar (as shown) or unipolar so that the ion beam 24 is always bent.

According to one exemplary aspect, again assuming an ideal point beam, the beam flux provided to the workpiece 18 is inversely proportional to the spacing of the trajectories of the beams 24a-24g. That is, the uniform spacing over time provided by scanner 40 between beams 24a-24b, 24b-24c, 24c-24d, etc. exits scanner 40 and produces a uniform flux . In this example, the various scan angles θa−θg are integer multiples of any given scan time t. However, due to the configuration of the magnetic poles 80A, 80B of the corrector 38 of FIG. Generate a changing flux . The varying flux has more flux at the edges 78 of the workpiece 18, where the beams are closer to each other, and less density at the center 88, where the beams are farther apart. Thus, while the non-uniform flux profile 86 of FIG. 5B is achieved, the non-uniform flux profile 86 exits the scanner and provides a uniform flux profile, which results from the uniform scan of FIG. 4B. gives an average flux Ψ ₀ similar to .

In accordance with another exemplary aspect, as shown in FIG. 6A, an improved scanner 90 is configured such that the scanner's magnets, in conjunction with a conventional correction magnet 68, provide a non-linear relationship between drive current and scan angle. can be done.

Accordingly, improved scanner 90 may be configured to provide flux profile 92 of FIG. 6B that is generally equivalent to flux profile 86 of FIG. 5B, assuming an ideal point beam and triangular current waveform. However, whereas conventional scanners provide uniform changes in scan angle for uniform changes in current, the magnetic poles of the scanner of the present disclosure provide a uniform change in scan angle such that uniform changes in current result in non-uniform changes in scan angle. It may be shaped to have a predetermined profile.

The flux profile 92 of FIG. 6B therefore utilizes the same input to the scanner 40 while achieving greater flux at the edges 78 to compensate for lost beam current associated with the edges of the scan with the actual ion beam. This can be achieved by Conventionally, the scanner 40 of FIG. 5A achieves the desired flux at the edge 78 by holding the ion beam 24 proximate the edge 78 for a longer period of time than the remainder of the workpiece 18. As such, the AC waveform to scanner 40 may be highly modified and potentially bandwidth limited. The present disclosure provides a solution to such complex and detrimental AC scanning waveforms. This allows the scanner and correction system to advantageously provide a greater amount of flux to the edges 78 of the workpiece.

For example, the flux at the edge(s) 78 of the workpiece 18 may be 10% to 100% greater than the flux at the center 88 of the workpiece. In another example, the flux profiles 86, 92 of FIGS. 5B and 6B may be generally parabolic with an unmodified scan waveform applied to the scanner 40. In yet another example, the flux profiles 86, 92 with unmodified scan waveforms are generally uniform over a central region associated with the center 88 of the workpiece 18 of FIGS. 5A and 6A, and at the edges 78 of the workpiece. increases only or primarily at the edges 78 of the workpiece. Here, said central region represents between 20% and 80% of the total length or diameter of the workpiece.

Thus, varying densities among beams 24a-24b, 24b-24c, 24c-24d, etc. create varying fluxes for non-uniform scanning of the beams by improved scanner 90. Thus, more flux is produced at the edges 78 of the workpiece 18 where the beams are closer together than one another, and a less dense flux is produced at the center 88 where the beams are further apart. In this example, the various scan angles θa-θg may be different for any given scan time t. Thus, when the improved scanner 90 is driven using the triangular current waveform 60 of FIG. 1C, the resulting trajectory of beams 24a-24g provides the flux profile 92 of FIG. 6B, which is similar to the flux profile 86 of FIG. 5B. do.

FIG. 7 shows a first function w ₁ and which relates the scan angle θ and the scan current I applied to the scanner by the actual beam after the uniformity correction corrects the scan waveform to provide a uniform flux . A second function w ₂ is shown. The first function w ₁ provides a uniform flux profile (eg, similar to uniform flux profile 76 of FIG. 3B) after uniformity correction when used with the conventional scanner and correction system of FIG. 3A. In the first function w ₁ , the slope is smaller at the extreme values 94 of the scan angle θ and larger at the middle 96 of FIG. The second function w ₂ is the uniformity corrected function for the improved system of the present disclosure, and the scan angle θ is a more linear function (linear function) of the scan current I.

According to another exemplary aspect, the present disclosure provides that the non-uniform flux profiles 86, 92 of FIGS. 5B and 6B may be achieved by a combination of the correction device 38 of FIG. 5A and the improved scanner 90 of FIG. 6A. to understand. For example, various designs of the physical magnets and magnetic poles 80A, 80B associated with either the corrector 38 of FIG. 5 and/or the improved scanner 90 of FIG. 6A are contemplated. Therefore, improved optics and techniques can be utilized when designing various magnetic pole shapes.

For example, FIG. 8 shows a first pole edge 100 and a second pole edge 102 configured to provide a particular desired flux profile. For example, first pole edge 100 and second pole edge 102 may be associated with conventional compensator 68 (eg, a standard S-shaped magnet) of FIG. 6A. On the other hand, the improved pole edges 104, 106, 108, 110 of FIG. 8 may be associated with the corrector 38 of FIG. 5A. The non-uniform flux profiles 86, 92 of FIGS. 5B and 6B are thereby generally defined by beam 24, respectively. The modified pole edges 104, 106, 108, 110 of FIG. 8 may be configured accordingly to achieve various desired optical properties of the magnet. For example, polar rotation, pole edge curvature, pole face curvature, etc. may be utilized in the configuration of improved pole edges 104, 106, 108, 110.

While some aspects of the present disclosure may relate to one embodiment of the ion implantation system described herein, other aspects relate to methods of increasing the throughput of workpieces through an ion implantation system. Although these methods are illustrated and described as a series of acts or events, it will be understood that the invention is not limited to the illustrated order of such acts or events. For example, some acts may occur in a different order and/or concurrently with other acts or events apart from those illustrated and/or described herein. Moreover, not all illustrated steps may be required to implement a methodology in accordance with one or more aspects or embodiments of the invention. Additionally, one or more of the operations depicted herein may be performed in one or more separate operations and/or phases.

FIG. 9 illustrates an example method 200 for controlling the flux profile of a scanned ribbon beam (eg, a scanned spot beam). In act 202 of FIG. 9, for example, a spot ion beam is provided to the scanner, and in act 204 a scanning waveform having a time-varying potential is applied to the scanner. The scanning waveform may include, for example, a triangular wave. In operation 206, the spot ion beam is scanned across a scan path to generally define a scanned ion beam of a plurality of beamlets within the scan path. In operation 208, the scanned ion beam passes through a correction device. Here, the correction device is configured to direct the scanning ion beam toward the workpiece at a substantially constant angle of incidence across the workpiece. In operation 210, the plurality of magnetic poles of the scanner and correction device provide a scanned ion beam to a workpiece with a non-uniform flux profile using an ideal point beam scanned across the workpiece.

Therefore, the present disclosure provides a non-uniform flux profile before uniformity correction in the ideal case. For example, the present disclosure provides that in the ideal case of a point beam scanned across a workpiece at a substantially constant scan rate, the flux increases substantially monotonically from the center of the workpiece to the edge of the workpiece. One or more scanners and correction devices configured as described above are contemplated. After uniformity correction with the actual beam, the flux profile is substantially uniform or has a predetermined non-uniformity. Conventionally, the edges of the workpiece experience reduced current for the various reasons discussed above, thus providing a generally parabolic flux profile with reduced flux near the edges of the workpiece. To account for this reduced flux near the edge, the ion beam is kept at the edge for a long time to increase the flux and achieve better uniformity, as shown in Figure 7. Gender correction routines have traditionally been performed. However, holding the ion beam at the edge in this manner wastes beam current. This is due, at least in part, to the portion of the ion beam width that extends beyond the workpiece when at the end of the scan.

The present disclosure advantageously utilizes a scanner and correction device to increase beam flux at the edges of a workpiece. As a result, when such lower currents are present at the edge, the net flux profile is flatter and the scanning system and uniformity correction are configured to hold the ion beam at the edge for shorter durations. can do. This results in less wasted beam current.

The present disclosure contemplates providing various magnetic fields to the corrector and/or scanner such that the pole shape, pole face rotation, and curvature associated with each magnet is adjusted to the desired non-uniformity described herein. Provide flux profile. For example, by changing the plane of the magnetic poles, the path length through the magnetic field of each beamlet across the ribbon beam can be effectively changed. Changing the path length through the magnetic field means changing the degree to which the beamlets bend, i.e. the beamlets are similarly changed and can exit the corrector in a parallel manner. However, according to the present disclosure, the beamlets associated with the edges of the workpiece are closer to each other than the middle of the workpiece. Therefore, the edges of the workpiece provide more flux than the middle.

While the 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. can. In particular, the terminology used to describe such components (blocks, units, engines, assemblies, devices, circuits, systems, etc.) with respect to the various functions performed by such components or structures (blocks, units, engines, assemblies, devices, circuits, systems, etc.) ”) are not structurally equivalent to the disclosed structures that perform the functions in the exemplary implementations of the invention illustrated herein, unless otherwise indicated. It is intended to correspond to any component or structure that performs the specified function of the described component (eg, is functionally equivalent). Furthermore, although certain features of the invention are disclosed with respect to only one of several implementations, such features may be desired or advantageous for any given or particular application. It may be combined with one or more other features of other implementations to obtain the desired results. Further, where the words "including", "includes", "having", "has", "with" or variations thereof are used in the detailed description and in any of the foregoing, To the extent that such terms are included, such terms are intended to be inclusive in a manner analogous to the term "comprising."

1 is an embodiment of an ion implantation system having a scanner, a correction device, and a dosimetry system in accordance with various aspects of the present disclosure. 1A is an embodiment of the scanner and several scanned ion beams of FIG. 1A; FIG. 1B is an embodiment of a triangular scanning current waveform in the scanner of FIGS. 1A and 1B; FIG. 1A is a perspective view of one scanning ion beam impinging on a workpiece at several separate points in time in the system of FIG. 1A; FIG. FIG. 2 is a perspective view of a magnetic pole and a beam guide of a conventional correction device. FIG. 2 is a schematic diagram of an ideal ion beam passing through an ideal scanner and correction device. 3B is a graph showing an ideal beam flux profile using the ideal scanner and correction device of FIG. 3A; FIG. 5 is a graph illustrating an example flux profile generated using a non-uniform triangular current waveform. FIG. 3 is a perspective view of a magnetic pole and beam guide of a correction device according to various aspects of the present disclosure. FIG. 2 is a schematic illustration of an ion beam passing through a scanner and correction device in accordance with various aspects of the present disclosure. 5B is a graph illustrating a non-uniform beam flux profile using the scanner and correction device of FIG. 5A; FIG. FIG. 3 is a schematic illustration of a scanned ion beam passing through another scanner and another correction device in accordance with various aspects of the present disclosure. 6B is a graph illustrating a non-uniform beam flux profile using the scanner and correction device of FIG. 6A; FIG. 2 is a chart illustrating first and second functions relating scan angle to scan current applied to a scanner in accordance with various aspects of the present disclosure. 3 is a chart illustrating various magnetic pole designs in accordance with various aspects of the present disclosure. FIG. 3 is a flow diagram illustrating a method of providing a non-uniform flux profile to a workpiece in accordance with various aspects of the present disclosure.

Claims (19)

an ion source that forms an ion beam;
a mass analyzer that performs mass analysis on the ion beam;
a power supply that provides a scanning waveform;
a magnetic scanner for selectively scanning the ion beam along a scan path based on the scanning waveform, the magnetic scanner defining a scanned ion beam comprised of a plurality of beamlets within the magnetic scanner; ,
a magnetic field correction device that directs the scanned ion beam toward a workpiece at a substantially constant angle of incidence across the workpiece;
The magnetic field correction device is arranged to move from the center of the workpiece towards the edge of the workpiece in the ideal case where the ideal point ion beam completely scans the entire workpiece at a substantially constant scanning speed. , an ion implantation system configured to provide a non-uniform flux profile having a substantially monotonically increasing flux . The ion implantation system of claim 1 , wherein the magnetic field correction device comprises a plurality of magnetic poles that define a non-uniform flux profile of the scanned ion beam at the workpiece. The ion implantation system of claim 1 , wherein the flux increases by 10% to 100% from the center of the workpiece toward the edges of the workpiece . The non-uniform flux profile includes the flux being substantially uniform over a central region of the workpiece and increasing at the edges of the workpiece, the central region ranging from 20% to 20% of the length of the workpiece. The ion implantation system of claim 1, wherein the ion implantation system corresponds to between 80%. The ion implantation system of claim 1, wherein the non-uniform flux profile is generally parabolic. The ion implantation system of claim 1 , further comprising a controller that controls the non-uniform flux profile through control of one or more of the magnetic scanner and the magnetic field correction device. The ion implantation system according to claim 1, wherein the magnetic field correction device includes a pair of opposite polarity dipole magnets having an S-shaped structure. an ion source that forms an ion beam;
a mass analyzer that performs mass analysis on the ion beam;
a scanner power supply that provides a scanning waveform;
a scanner for selectively scanning the ion beam along a scan path based on the scanning waveform, the scanner defining a scanned ion beam comprised of a plurality of beamlets;
a magnetic field correction device that directs the scanned ion beam toward a workpiece at a substantially constant angle of incidence across the workpiece;
The magnetic field correction device is arranged to move from the center of the workpiece towards the edge of the workpiece in the ideal case where the ideal point ion beam completely scans the entire workpiece at a substantially constant scanning speed. , an ion implantation system configured to provide a non-uniform flux profile having a substantially monotonically increasing flux . 9. The ion implantation system of claim 8 , further comprising a controller that controls the non-uniform flux profile via control of one or more of the scanner and the magnetic field correction device. 10. The controller of claim 9 , wherein the controller is further configured to control the scanner power supply so that the scanner is further configured to provide the non-uniform flux profile of the scanned ion beam at the workpiece. Ion implantation system as described. 9. The ion implantation system of claim 8 , wherein the scanner includes a magnetic scanner. 9. The ion implantation system according to claim 8 , wherein the magnetic field correction device includes a pair of opposite polarity dipole magnets having an S-shaped structure. 9. The ion implantation system of claim 8 , wherein the flux increases by 10% to 100% from the center of the workpiece toward the edges of the workpiece . 9. The ion implantation system of claim 8 , wherein the non-uniform flux profile is generally parabolic. The non-uniform flux profile is substantially uniform over a central region and increases only at the edges of the workpiece, the uniform region being between 20% and 80% of the length of the workpiece. A corresponding ion implantation system according to claim 8 . 9. The ion implantation system of claim 8 , wherein the magnetic field correction device comprises a plurality of magnetic poles that define a non-uniform flux profile of the scanned ion beam at the workpiece. A method of providing a non-uniform flux of a scanning ribbon ion beam, the method comprising:
a step of supplying a spot ion beam to a scanner;
providing a scanning waveform having a time-varying potential to a scanner and scanning the ion beam across a scanning path at the scanner to generally define a scanned ion beam comprised of a plurality of beamlets;
passing the scanning beam through a correction device;
The correction device directs the scanned ion beam at a substantially constant angle of incidence across the workpiece, and the correction device directs the scanned ion beam at a substantially constant angle of incidence across the workpiece, and the correction device directs the scanning ion beam at a substantially constant angle of incidence across the workpiece. Featuring multiple magnetic poles that provide a non-uniform flux profile for the scanned ion beam ,
The non-uniform flux profile is directed from the center of the workpiece towards the edges of the workpiece in the ideal case where an ideal point ion beam completely scans the entire workpiece at a substantially constant scan rate. , including a substantially monotonically increasing flux . 18. The method of claim 17, wherein the time-varying potential is associated with at least one of a time-varying voltage or a time-varying magnetic field. 18. The method of claim 17 , wherein the flux increases by 10% to 100% from the center of the workpiece toward the edges of the workpiece .

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