Compact low angle ion beam extraction assembly and processing device

Abstract

The extraction assembly may include an extraction plate for placement along a side of the plasma chamber having an extraction aperture elongated along a first direction with an aperture height extending along a second direction perpendicular to the first direction. The extraction plate defines an inner surface along the extraction aperture that is in a first plane. A beam blocker is positioned over the extraction aperture and has an outer surface disposed in a second plane different from the first plane. Thus, the beam blocker overlaps with the extraction plate along a first edge by a first overlap distance and overlaps with the extraction plate along a second edge by a second overlap distance to define a first extraction slit along a first edge of the extraction aperture and a second extraction slit along a second edge of the extraction aperture.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of, and claims priority to, U.S. Non-Provisional Application No. 17 / 502,777, entitled "COMPACT LOW ANGLE ION BEAM EXTRACTION ASSEMBLY AND PROCESSING APPARATUS," filed on October 15, 2021, which claims priority to, U.S. Non-Provisional Application No. 17 / 503,334, entitled "COMPACT LOW ANGLE ION BEAM EXTRACTION ASSEMBLY AND PROCESSING APPARATUS," filed on October 17, 2021, which is incorporated herein by reference in its entirety.

[0002] The present embodiment relates to a plasma processing apparatus, and more particularly to a low-angle ion beam extraction optical system. [Background technology]

[0003] Conventional equipment used to process substrates with ions includes beamline ion implanters and plasma immersion ion implantation tools. Both are suitable for implanting ions over a range of energies. In beamline ion implanters, ions are extracted from a source, mass-analyzed, and then transported to the substrate surface. In plasma immersion ion implanters, a substrate is placed in the same chamber, and a plasma is generated adjacent to the plasma. The substrate is set at a negative potential relative to the plasma, and ions crossing a plasma sheath in front of the substrate are incident on the substrate at a zero angle of incidence with respect to the normal or perpendicular to the substrate's major surface. Recently, a new processing system has been developed that provides an angled ion beam for substrate processing in a compact configuration. Ions are extracted through a specially shaped aperture in an extraction plate placed in close proximity to the plasma. The ions are extracted at a non-normal angle of incidence with respect to the substrate's major surface. Such systems facilitate the processing of non-planar surfaces, such as for processing structures with sidewalls that extend along the normal to the major surface.

[0004] One type of compact angled ion beam device employs an extraction aperture adjacent to a plasma chamber to extract an ion beam from a plasma contained therein. To uniformly process the device structure, a beam blocker member may be positioned in the center of the extraction aperture, which creates pairs of angled ion beamlets directed at opposite angles relative to the substrate (symmetric with respect to a normal to a major surface of the substrate) so that opposite surfaces of the device structure, such as opposite sidewalls of a trench, can be exposed in a single process.

[0005] Often the extraction aperture has an elongated shape, so that a pair of ribbon ion beams are extracted, perhaps with a height of a few millimeters to a few centimeters and a width of up to several hundred mm. If the ion beam is wider than the substrate to be processed (e.g., a 300 mm Si wafer), the entire substrate can be exposed to two symmetrical ion beamlets by scanning the substrate in front of the extraction aperture in a direction perpendicular to the elongation of the extraction aperture.

[0006] Although the presence of a beam blocker facilitates the creation of an angled ion beam, the beam current extracted through the extraction aperture is reduced by the presence of the beam blocker. This reduction in beam current can be addressed by providing multiple extraction apertures along the side of the plasma chamber to simultaneously generate multiple pairs of symmetrical ion beamlets. However, if the plasma is not uniform within the plasma chamber, the ion beams extracted from different extraction apertures located at different positions along the plasma chamber may differ from each other. Therefore, different areas of the substrate exposed to different extraction apertures may be treated with different ion beams having different characteristics, such as different angles of incidence.

[0007] Another issue when processing substrates using angled ions is controlling the angle of incidence. While angled ion beams may be characterized by a mean angle, angled ion beams are generated with a distribution of angles of incidence, sometimes referred to as the "angular spread." In some applications, processing substrates over a relatively wide angular spread is acceptable. In other applications, a relatively narrow angular spread may be required, including cases where the mean angle of incidence is relatively low. Currently, no extraction device is available to meet the above requirements. It is with respect to these and other considerations that the present disclosure is provided. Summary of the Invention

[0008] This Summary is intended to introduce in simplified form some of the concepts described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to aid in determining the scope of the claimed subject matter.

[0009] In one embodiment, An extractor assembly is provided, the extractor assembly comprising: Located along the side of the plasma chamber will be Extraction Plate The extraction plate is , extending along a second direction perpendicular to the first direction Aperture height do , in the first direction stretched alongWith extraction aperture is doing The extractor plate defines an inner surface along the extractor aperture, which is in a first plane. A beam blocker is disposed over the extractor aperture and has an outer surface disposed in a second plane, different from the first plane, toward the interior of the extractor plate. Thus, the beam blocker overlaps with the extractor plate along the first edge by a first overlap distance and along the second edge by a second overlap distance to define a first extractor slit along the first edge of the extractor aperture and a second extractor slit along the second edge of the extractor aperture.

[0010] In another embodiment, the processing apparatus includes a plasma chamber for containing the plasma and an extraction plate configured along a side of the plasma chamber. and , the extraction plate , th extending along a second direction perpendicular to the first direction elongated along a first direction having an extraction aperture height With extraction aperture is doing The extraction plate may define an inner surface along the extraction aperture, which is in a first plane. The processing device may further include a beam blocker disposed over the extraction aperture and having an outer surface disposed in a second plane different from the first plane, toward the interior of the extraction plate. Thus, the beam blocker may overlap with the extraction plate along the first edge by a first overlap distance and along the second edge by a second overlap distance to define a first extraction slit along the first edge of the extraction aperture and a second extraction slit along the second edge of the extraction aperture.

[0011] In a further embodiment, a compact angled ion beam device is provided, comprising: a plasma chamber for storing a plasma; and an extraction assembly disposed adjacent to the plasma chamber and including an extraction plate arranged along a side of the plasma chamber. The extraction plate may include an extraction aperture elongated along a first direction with an aperture height extending along a second direction perpendicular to the first direction, and the extraction plate defines an inner surface along the extraction aperture in a first plane. The device may include a beam blocker disposed over the extraction aperture and having an outer surface disposed in a second plane, different from the first plane, toward the interior of the extraction plate. The device may further include a coupling assembly reversibly coupling the beam blocker to the extraction plate, the coupling assembly configured to adjust an overlap distance between the extraction plate and the beam blocker along the second direction and to adjust a slit width of the extraction assembly, the slit width comprising the distance between the extraction plate and the beam blocker along a third direction perpendicular to the first and second planes. [Brief explanation of the drawings]

[0012] [Figure 1A] 1 illustrates an embodiment of an apparatus. [Figure 1B] FIG. 1 illustrates a close-up view of an exemplary extraction assembly. [Figure 1C] FIG. 10 is a front view illustrating the geometry of a substrate and substrate holder relative to an extraction assembly according to an embodiment of the present disclosure. [Figure 1D] FIG. 10 illustrates details of an extraction assembly according to an embodiment of the present disclosure. [Figures 2A-2C] 1 presents simulations of electrostatic equipotential lines and ion trajectories for three different variations of an embodiment of the present disclosure. [Figure 3A] 2C presents emissivity curves and angular distributions for three different variations of the embodiment shown in FIGS. 2A-2C. [Figure 3B]2C presents emissivity curves and angular distributions for three different variations of the embodiment shown in FIGS. 2A-2C. [Figure 3C-3E] 10A-10C illustrate current measurements as a function of beam angle for different values of overlap between the beam blocker and the extraction plate according to different embodiments of the present disclosure. [Figure 4A] FIG. 1 illustrates an implementation of an apparatus for processing a substrate. [Figure 4B] FIG. 1 presents an example of a well-tuned beam ion angular distribution (IAD). [Figure 4C] FIG. 4C shows a less well-adjusted beam with the same mean angle as shown in FIG. 4B. [Figure 5A] 13A-13D illustrate an extraction assembly according to an additional embodiment of the present disclosure. [Figure 5B] FIG. 5B shows a detailed view of the extraction assembly of FIG. 5A. [Figures 6A-6C] 1A-1C illustrate three different configurations of an extraction assembly according to embodiments of the present disclosure. [Figures 6D-6F] 1A-1C illustrate three different configurations of an extraction assembly according to embodiments of the present disclosure. [Figure 6G] 1A and 1B show back and front views of an extraction plate-beam blocker assembly. [Figures 7A-7D] 10A-10C present simulations of electrostatic equipotential lines and ion trajectories for four different variations of an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which several embodiments are shown. The subject matter of this disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the subject matter to those skilled in the art. In the drawings, like numbers refer to like elements throughout.

[0014] The embodiments described herein provide apparatus, systems, and methods for controlling the angular distribution of ions directed at a substrate using an ion-optics arrangement composed of a beam blocker-extraction plate assembly. In particular, the embodiments provide a novel extraction system for producing an ion beam from a plasma with a controlled low incidence angle and small "angular spread." References herein to "incidence angle" may refer to the average angle of incidence of ions in the ion beam relative to a reference direction, such as a normal to the substrate, while the term "angular spread" may refer to the width of the distribution or range of incidence angles around the average angle.

[0015] As described in detail below, a novel ion beam apparatus is disclosed in which the angle of incidence of an ion beam is paradoxically controlled using an extraction system to block the plasma in a plasma chamber from the normal (perpendicular) line of sight to the substrate being processed. As a result, the beam current of the extracted ion beam can be reduced, providing the previously unrealized advantage of producing a low-angle ion beam with a narrow angular spread. For plasma processing of high aspect ratio device structures, the provided apparatus, systems, and methods provide the advantage of having an ion beam that can adequately treat targeted surfaces, such as sidewalls, of these structures without affecting other surfaces.

[0016] FIG. 1A illustrates an embodiment of an apparatus 100 according to an embodiment of the present disclosure. FIG. 1B illustrates an expanded view of an exemplary extraction assembly. The apparatus 100 includes a plasma chamber 1 in which an inductively coupled plasma (ICP) is generated by an RF power supply 5, a matching network 6, and an RF antenna 4. The plasma chamber 1 may receive gas species through a manifold 2 and an operating gas line 3. To generate an angled ion beam, an extraction assembly including a beam blocker 7 and an extraction plate 8 is provided. In some embodiments, the plasma chamber 1 and the beam blocker 7 and extraction plate 8 may be formed from a dielectric material (e.g., alumina, quartz, aluminum nitride).

[0017] A process chamber 20 is disposed adjacent to the plasma chamber 1. Positive ions can be extracted from the plasma chamber by holding the plasma chamber 1 at ground potential and applying a negative bias to a substrate 10 and substrate holder 11 disposed in the process chamber 20 using a bias source 12. Unlike known plasma processing tools in which the ion incidence angle at the wafer is zero (relative to a normal (z-axis) to the main surface (xy plane) of the substrate), in this embodiment, a beamlet of ions strikes the surface of the substrate 10 at a non-zero incidence angle. For example, in various non-limiting embodiments, these non-zero incidence angles can be symmetrically spaced about 0 degrees between -α and +α. The magnitude of these angles is a function of the plasma density and the extraction voltage (negative bias voltage applied on the substrate).

[0018] In some embodiments, an additional gas injection line 14 may be provided, connected to a gas showerhead 15 to generate a gas flow 16. A vertical motion stage 17 and a rotary motion stage 18 may be provided to impart various types of motion to the substrate 10.

[0019] The extraction plate 8 defines an extraction aperture 22, and the beam blocker 7 is positioned adjacent to the extraction aperture 22 to define a first extraction slit 24 and a second extraction slit 26. A first plasma meniscus 13 and a second plasma meniscus 13 are formed at each of the two extraction slits 24 and 26 (see FIG. 1B). An ion beam 9, shown as two separate beamlets, is extracted through the first extraction slit 24 and the second extraction slit 26. During processing, the substrate 10 can be scanned up and down (along the y-axis) in front of the two extraction slits by the vertical motion stage 17. As shown in FIG. 1C, the extraction aperture 22, the beam blocker 7, and thus the first extraction slit 24 and the second extraction slit 26, can be extended along the x-direction to extend across the entire width of the substrate 10. In this way, the entire substrate surface of the substrate 10 can be exposed to the ion beam 9 during a scan along the y-axis. For a given scan speed, the number of scans is determined based on the required ion dose and the available ion beam current.

[0020] For illustrative purposes, if the substrate scan speed is 10 cm / s and the ion beam height along the y-axis at the substrate location is 30 mm, the time spent by any substrate surface undergoing ion bombardment is 300 milliseconds. If the ion beam 9 is extracted as a pulsed ion beam with a pulse frequency of 40 kHz and a duty cycle of 50%, the substrate surface will be exposed to approximately 6,000 cycles of ion bombardment while passing in front of the extraction aperture. Under these conditions, the processing yield (e.g., etch rate) of the substrate may be a complex function of ion energy, ion flux, angle of incidence, and the nature of the material being processed by the ion beam 9. High process uniformity can be achieved by using the rotary motion stage 18, which allows wafer rotation in 0.1° increments over a full 360°.

[0021] 1D, further details of an extraction assembly 30 according to an embodiment of the present disclosure are shown. In this embodiment, the extraction plate 8 is provided as an electrically insulating dielectric material having extraction apertures 22, as shown. The extraction apertures 22 may extend along a first direction, which refers to the x-direction in the illustrated Cartesian coordinate system. The extraction apertures 22 may extend along a second direction, H, which is perpendicular to the first direction (i.e., along the y-direction). EP The extraction plate 8 defines an inner surface 40 aligned with the extraction aperture 22, which lies in a first plane P1. The beam blocker 7 has an outer surface 42, facing inward of the extraction plate 8, disposed in a second plane P2 that is different from but parallel to the first plane P1.

[0022] As further shown in FIG. 1D, the beam blocker 7 is BL 1D , and is configured to overlap with the extraction plate 8 by a first overlap distance O1 along a first edge 44 of the extraction aperture 22 and a second overlap distance O2 along a second edge 46 of the extraction aperture 22. These overlap distances ensure that there is no vertical (along the Z-axis) line of sight between the plasma side PL of the extraction assembly 30 and the substrate side SU of the extraction assembly. This configuration differs from known extraction assembly configurations in which a beam blocker is provided in the center of the extraction aperture to facilitate extraction of sufficient beam current from the plasma. However, the inventors have discovered that the configuration of FIG. 1D can provide special beam characteristics, as described below.

[0023] To illustrate the effect of the architecture of Figures 1A-1D, Figures 2A-2C present simulations of electrostatic equipotential lines and ion trajectories for three different variations of the disclosed embodiment. In particular, in the simulations shown, the beam blocker 7 has the following dimensions: a thickness of 5 mm along the z direction and a height h BLThe beam blocker 7 may extend 450 mm along the x-direction (perpendicular to the plane of the drawing). Adjacent to the beam blocker 7 is an extraction plate 8, which component also forms one of the walls of the plasma chamber 200. The extraction plate 8 has a rectangular aperture extending 420 mm along the x-direction and a height h along the y-axis. EP For illustrative purposes, in FIG. 2A, the beam blocker 7 and the extraction plate 8 have the same height h BL =h EP , and is aligned in such a manner that the beam blocker 7 completely overlaps the extraction aperture 22. The outer surface 42 of the beam blocker 7 is recessed 4 mm from the inner surface 40 of the extraction plate 8, so that the blocker-extraction plate assembly forms two equivalent slits (13 b) through which the beamlets (shown as ion beam 9) are extracted. The beam blocker 7 and extraction plate 8 are fabricated from a dielectric material (alumina was used in this simulation), which forms the bulk of these components and which, in a practical implementation, may be coated with a thin protective film (also dielectric) to withstand the harsh chemical reaction environment in a given plasma chamber.

[0024] From an electrostatic standpoint, the dielectric material of the beam blocker 7 and the extraction plate 8 is transparent to electric field lines, meaning that the electric field lines penetrate the extraction plate 8 and project into the plasma in the plasma chamber 200. The trajectory characteristics of the ions emerging through the slit 13b are determined by the shape and location of the plasma meniscus, which forms the boundary between the plasma and the vacuum, relative to the right side of the extraction assembly. Meniscus formation is the result of an equilibrium between the "plasma pressure," which pushes the plasma outward from the slit 13b, and the "electrostatic pressure," which pushes the plasma inward from the slit 13b. These two antagonisms are quantified by the plasma density for the former and the electrostatic field for the latter. Mathematically, this condition is expressed as an equilibrium between the Bohm currents at the plasma sheath edge: j Bohm =ens v Bohm (1) where e represents the elementary charge and n s is the plasma density at the sheath edge (n s = 0.61n0, where n0 is the bulk plasma density), and v Bohm =(k B T e / m i ) 1 / 2 is the Bohm velocity and k B , T e , and m i are the Boltzmann constant, the electron temperature, and the ion mass, respectively. The Child-Langmuir space-charge limited current is TIFF0007723838000001.tif30170, where ε0 is the permittivity of free space and V e is the extraction voltage, and z is the extraction gap length (the distance between the slit and the wafer).

[0025] Under these conditions, the extraction plate height h along the y direction EP beam blocker height (along the y direction) h BL As Δy increases, the plasma meniscus moves deeper into the plasma and becomes more concave. The relative overlap between the beam blocker 7 and the extraction plate is represented in Figures 2A-2C as the parameter Δy. As shown by the transitions between Figures 2A, 2B, and 2C for values of Δy of 0 mm, 1 mm, and 2 mm, respectively, the extracted beam current is substantially reduced as the meniscus retreats into the plasma, and there is no vertical line of sight between the plasma chamber 200 and the process chamber 204. Furthermore, the beam average angle of incidence relative to the normal (z-axis) to the major surface (x-y) of the substrate 10 increases slightly.

[0026] In particular, a side effect of this change in geometry, which creates an overlap between the beam blocker 7 and the extraction plate 8, is that the beam angular spread is significantly reduced, as will be explained in more detail below. In other words, the ion trajectories of the beamlets forming the ion beam 9 are incident on the substrate 10 over a much narrower range of incidence angles.

[0027] 3A and 3B show that in the middle of the operating range, V e =1kV, z gap OPERA modeling results for emissivity curves for the three geometries shown in Figures 2A-2C are shown, using ion source "average" operating parameters for the plasma chamber (ion source): Δy = 10 mm (see Figure 2C), and P = 600 W. Figure 3A plots the average angle of incidence as a function of position on the substrate for three different ion extraction geometries, with Δy varied as shown. The average angle is plotted in absolute terms relative to the z-axis (0 degrees) so that the two different beamlets (which together define the ion beam 9) define either positive or negative angles of incidence relative to the normal (z-axis). For positions between approximately 4 mm and approximately 12 mm (+ or -), where ion impact occurs, the average angle is slightly higher, such as when the beam blocker 7 and extraction plate 8 overlap Δy is 2 mm, increasing by 2-3 degrees for a beam blocker 7 / extraction plate 8 overlap of 0 mm relative to Δy.

[0028] Figure 3B plots current density as a function of average angle for the same three different ion extraction geometries, with Δy varied as shown. As in Figure 3A, the results reflect the effect of two different beamlets, positioned symmetrically about 0 degrees (z-axis). As shown, for Δy = 0 mm, the beam current is distributed over a wider range of angles than when the overlap is 1 mm or 2 mm. More quantitatively, the beam angular spread (BAS) decreases from 10° to 6° as Δy increases from 0 mm to 2 mm.

[0029] In addition to the results in Figures 3A-3B, Figures 3C, 3D, and 3E show the results of current measurements as a function of beam angle when Δy values are 0 mm, 1 mm, or 2 mm (a schematic depiction of the extraction geometry is shown on the left side of the figure). The experimental results shown in Figures 3C, 3D, and 3E are based on plasma generated by flowing a mixture of Ar / CF4 at a ratio of 20 sccm / 10 sccm into the plasma chamber and extracting the ion beam through a given extraction assembly at a bias of 2.25 kV. The distance between the extraction plate and the substrate (z-gap) in these experiments was held constant at 30 mm. The extraction aperture height along the y-axis was also constant at 30 mm in these experiments. Therefore, different values of Δy were set by selecting different beam blocker heights from 30 mm to 32 mm to 34 mm. Note that the beam blocker is positioned symmetrically above the extraction aperture in these examples, such that the value of Δy is determined as (beam blocker height - extraction aperture height) / 2. Therefore, a combination of a 34 mm beam blocker and a 30 mm extraction aperture results in a Δy value of 2 mm.

[0030] As shown in the graph, the beam angle spread at a Δy value of 2 mm (Figure 3E) is substantially narrower than the beam angle spread at a Δy value of 0 mm (Figure 3C). More quantitatively, the beam angle spread (BAS) decreases from 13.4° at a Δy of 0 mm to 9.4° at Δy = 2 mm, while the average beam angle increases from 13.6° to 17.7°. Also, the significant ion current tail toward very low angles (<5°) shown in Figure 3C for the Δy value of 0 mm disappears when Δy = 2 mm.

[0031] The significance of these differences is highlighted below with respect to Figures 4A-4C. Referring to Figure 4A, one implementation of an apparatus 100 for processing a substrate 10 is shown. In this example, an ion beam 9 is directed as two beamlets relative to the substrate on trajectories with average angles of +α or -α relative to the z-axis. The substrate 10 includes pattern features with sidewall SWLs. Thus, the ion beam 9 can affect various portions of these features, including the sidewall SWLs. When configured as an array, these features also define trenches with sidewall SWLs and a bottom surface B. Depending on the magnitude of α and the aspect ratio of these trenches, the ion beam 9 may or may not affect the bottom surface B.

[0032] In an example where an angled ion beam is used to create trench extensions along the y-direction, the ion beam 9 is designed to etch the sidewall SWL of the trench. In some device structures with trench features, the aspect ratio can be approximately 4.5:1 or greater. Using the example of a 4.5:1 aspect ratio, this geometry defines an acceptance beam angle of approximately 13°, meaning that an ion beam with an incidence angle higher than 13° will not significantly affect the sidewall SWL because the lower portion of the sidewall SWL is shadowed by the upper portion of the trench feature (e.g., a hard mask). Therefore, in these applications, a relatively low incidence angle is required to etch the sidewalls of high-aspect-ratio trenches. Furthermore, etching of the vertical wall (SWL) should be performed without recessing the bottom surface B. To achieve these dual goals, a well-tuned, low-angle ion beam with a low beam angle spread is required. Figure 4B presents an example of a well-tuned beam ion angular distribution (IAD) to meet the above requirements for the given trench feature shown (for clarity, only one of two symmetric beamlets is sketched). The average angle of the ion beamlets is shown as α, with a beam angular spread of Δα. In this case, the ion flux is incident over a range of angles such that ions strike the sidewall SWL from top to bottom, but not the bottom surface B. Thus, because the top of the feature is fabricated from an etch-resistant material (hard mask), etching occurs along the sidewall SWL but not along the bottom surface B.

[0033] In contrast, Figure 4C shows a less well-aligned beam with the same mean angle (again shown as α) but with a wider angular spread (shown as Δβ). While the portion of the IAD representing ions with trajectories below a given minimum angle (shown as the shaded area) reaches the bottom surface B of the trench, ions with trajectories above the maximum angle also tend to cause excessive etching of the top surface. Thus, the above example demonstrates the usefulness of providing a narrow ion angular distribution, including for cases with low mean angles of incidence, where small deviations in the angle of incidence can adversely affect the substrate processing process by hitting unwanted areas.

[0034] FIG. 5A illustrates an extractor assembly 300 according to an additional embodiment of the present disclosure. In addition to an extractor plate 8, the extractor assembly 300 includes a coupling assembly 310 used to couple a beam blocker, generally designated as beam blocker 7, to the extractor plate 8. The coupling assembly 310 includes a mounting pin 302 and a screening washer 304, which are used to connect the beam blocker 7 to the extractor plate 8. As will be described in more detail with respect to FIGS. 6A-6C below, the coupling assembly 310 provides flexibility in the placement of the beam blocker 7 relative to the extractor plate 8 and, therefore, relative to the extraction aperture 22. As shown in the detailed view of FIG. 5B, this flexibility allows for independent adjustment of the overlap Δy and the size of the extractor slits 24, 26, designated as the slit width or sw.

[0035] 6A-6C, three different configurations of the extraction assembly 300 are shown. In particular, perspective cross-sectional views are shown with the main sections taken along the xz plane. In particular, the xz plane views are taken along section A-A', located near end portion E of extraction aperture 22, midway through the beam blocker-extraction plate assembly, as represented in the top view of FIG. 6G. In FIGS. 6D-6F, cross sections of the extraction plate 8 and beam blocker in the region of extraction aperture 22, corresponding to those of FIGS. 6A-6C, are shown along the yz plane and are represented in section C-C' of FIG. 6G.

[0036] As shown in FIG. 6A, the coupling assembly 310 includes a screening washer 304 and a mounting pin 302, as well as a lock washer 308. In the configuration of FIG. 6A, a variation of the beam blocker 7 is provided, shown as beam blocker 307. The beam blocker 307 includes a ridge 309, which may be considered a first ridge. Similarly, a second ridge may be disposed on the beam blocker 307 at the opposite end of the beam blocker 307 (along the x-direction). The coupling assembly 310 further includes a shim assembly 306, which may include one or more spacers or shims. As shown in FIG. 6A, one shim of the shim assembly 306 is disposed between the ridge 309 and the extraction plate 8. The placement of one or more shims or spacers between the extraction plate 8 and the ridge 309 facilitates changing the distance, or sw, between the outer surface 42 of the beam blocker 307 and the inner surface 40 of the extraction plate 8, as shown in FIG. 6D. 6D, the extraction aperture 22 may have a height along the y-axis of 30 mm, while the beam blocker 307 has a height of 32 mm, allowing for a 1 mm symmetric overlap of the beam blocker 307 and the extraction plate 8 along each edge of the extraction aperture 22. In one embodiment where the spacer of the shim assembly 306 has a thickness of 1 mm, the resulting slit width of the extraction slit 24A, shown as sw, may be 3.17 mm.

[0037] 6B, coupling assembly 310 may be used to connect another variation of beam blocker 7, shown in this case as beam blocker 317, to extraction plate 8. Beam blocker 317 also includes ridge 319, which may be considered a first ridge. Similarly, at the opposite end of beam blocker 317 (along the x-direction), a second ridge may be disposed on beam blocker 317. Coupling assembly 310 further includes shim assembly 316, which includes two spacers disposed between ridge 319 and extraction plate 8.

[0038] The placement of two shims or spacers between the extraction plate 8 and the ridge 319 facilitates further increasing the slit width distance, or sw, between the outer surface 42 of the beam blocker 317 and the inner surface 40 of the extraction plate 8, as shown in FIG. 6E. In one example of FIG. 6E, the extraction aperture 22 may have a height along the y-axis of 30 mm, while the beam blocker 317 has a height of 34 mm, allowing for a 2 mm symmetric overlap between the beam blocker 317 and the extraction plate 8 along each edge of the extraction aperture 22. In one embodiment in which the spacers of the shim assembly 306 have a thickness of 1 mm, the resulting sw of the extraction slit 24B may be 4.09 mm.

[0039] As shown in FIG. 6C, the coupling assembly 310 can be used to connect another variation of the beam blocker 7, shown in this case as beam blocker 327, to the extraction plate 8. The beam blocker 327 also includes a ridge 329, which may be considered a first ridge. Similarly, a second ridge may be disposed on the beam blocker 327 at the opposite end of the beam blocker 317 (along the x-direction). The coupling assembly 310 further includes a shim assembly 326, which includes two spacers disposed between the beam blocker 327 and the extraction plate 8. In this example, the ridge 329 is a “reverse” ridge in that the ridge 329 is disposed on the top surface of the beam blocker 327, away from the extraction plate 8. Thus, the outer surface 42 of the beam blocker 327 is spaced further away from the inner surface 40 of the extraction plate 8, as shown in FIG. 6F.

[0040] In one example of FIG. 6F , extraction aperture 22 may have a height along the y-axis of 30 mm, while beam blocker 327 has a height of 34 mm, thereby allowing for a 2 mm symmetric overlap between beam blocker 327 and extraction plate 8 along each edge of extraction aperture 22. In one embodiment, in which the spacers of shim assembly 306 have a thickness of 1 mm, the resulting sw of extraction slit 24B may be 5.77 mm. The above examples of Δy and sw are merely examples, and any additional suitable combinations may be readily provided by coupling assembly 310. Furthermore, while these examples are given in terms of mm dimensions, according to various embodiments, overlap Δy may be expressed in terms of the slit width of the extraction aperture; i.e., the ratio of overlap on both edges of the extraction aperture to the extraction slit width (sw) may be approximately 0.1 to 1.0.

[0041] Thus, the coupling assembly 310 provides a flexible way to vary the degree of overlap (Δy) between the beam blocker and the extraction plate, as well as the slit width or gap between the beam blocker and the extraction plate along the z direction. The benefits of this flexibility are further described with respect to Figures 7A-7D.

[0042] Similar to the simulations of FIGS. 2A-2C, FIGS. 7A-7D present simulations of electrostatic equipotential lines and ion trajectories for four different variations of an embodiment of the present disclosure. In particular, the modeling results shown in these figures show the ion beam shapes for two different beam blocker heights, resulting in values of Δy = 1 mm and Δy = 2 mm, and two different slit widths, sw = 4 mm and sw = 6 mm. These simulation results indicate that increasing the beam blocker height results in lower beam current. This result is not unexpected because, as noted above, in known configurations of extraction assemblies, the beam blocker does not overlap with the extraction plate to ensure sufficient beam current is extracted from the plasma. Also shown in these figures, increasing the slit width results in a wider beam footprint on the wafer, implicitly increasing beam current. Thus, the coupling assembly 310 facilitates the ability to independently adjust the overlap between the beam blocker and the extraction plate to narrow the beam angular spread, and to independently adjust the slit width to increase or decrease the extractable beam current for a given overlap, by easily coupling different configurations of beam blocker and shim assemblies to the extraction plate.

[0043] As can be seen in Table I, for a height Δy=2 mm, the extracted ion beam current for a slit width of 6 mm gives a beam current of 3.88 mA, which is 17.5% greater than the beam current value for a slit width of 4 mm with Δy=0 mm. TIFF0007723838000002.tif41170

[0044] According to the present disclosure, various embodiments may provide the following advantages: First, the present embodiments provide the ability to etch high aspect ratio holes, which require a low angle of incidence and a narrow angular spread to adequately etch the targeted surface of the hole. Second, the presently disclosed embodiments provide easy adjustability of the extracted beam current, independent of the amount of overlap between the extraction plate and the beam blocker, to maintain an acceptable level of beam current for ion beams with a narrow angular spread.

[0045] The present disclosure should not be limited in scope by the specific embodiments described herein. Indeed, various other embodiments of and modifications to the present disclosure, in addition to those described herein, will be apparent to those skilled in the art from the foregoing description and the accompanying drawings. Accordingly, such other embodiments and modifications are intended to fall within the scope of the present disclosure. Moreover, while the present disclosure has been described herein in the context of particular embodiments in particular environments for particular purposes, those skilled in the art will recognize that its usefulness is not limited thereto, and that the present disclosure may be beneficially implemented in any number of environments for any number of purposes. Accordingly, the claims set forth below should be construed in light of the full scope and spirit of the present disclosure as described herein.

Claims

1. an extraction plate disposed along a side of the plasma chamber, the extraction plate having an extraction aperture elongated along a second direction perpendicular to the first direction, the extraction aperture having an extraction aperture height extending along the second direction, the extraction plate defining an inner surface along the extraction aperture that lies in a first plane; a beam blocker disposed over the extraction aperture and having an outer surface disposed in a second plane, different from the first plane, toward the inside of the extraction plate; 1. An extraction assembly comprising: the beam blocker overlaps with the extraction plate along a first edge of the extraction aperture by a first overlap distance and along a second edge of the extraction aperture by a second overlap distance to define a first extraction slit along the first edge of the extraction aperture and a second extraction slit along a second edge of the extraction aperture; An extraction assembly, wherein the extraction plate and the beam blocker comprise a dielectric material.

2. 2. The extraction assembly of claim 1, wherein the first plane and the second plane define an extraction slit width for the first extraction slit and the second extraction slit, the extraction slit width being a separation distance between the first plane and the second plane along a normal to the first plane and the second plane.

3. An extraction plate positioned along a side of a plasma chamber, said extraction plate having an extraction aperture elongated along a first direction having an extraction aperture height extending along a second direction perpendicular to said first direction, said extraction plate defining an inner surface aligned with said extraction aperture in a first plane; a beam blocker disposed over the extraction aperture and having an outer surface disposed in a second plane, different from the first plane, toward the inside of the extraction plate; 1. An extraction assembly comprising: the beam blocker overlaps with the extraction plate along a first edge of the extraction aperture by a first overlap distance and along a second edge of the extraction aperture by a second overlap distance to define a first extraction slit along the first edge of the extraction aperture and a second extraction slit along a second edge of the extraction aperture; the first plane and the second plane define an extraction slit width for the first extraction slit and the second extraction slit, the extraction slit width being a separation distance between the first plane and the second plane along a normal to the first plane and the second plane; an extractor assembly, wherein the first overlap distance and the second overlap distance are equal to 10% to 100% of the extractor slit width;

4. The extractor assembly of claim 3 , wherein the extractor slit width is equal to 5% to 40% of the extractor aperture height.

5. 10. The extraction assembly of claim 1, wherein the beam blocker comprises a first ridge disposed along a first end of the beam blocker and a second ridge disposed along a second end of the beam blocker.

6. An extraction plate positioned along a side of a plasma chamber, said extraction plate having an extraction aperture elongated along a second direction perpendicular to the first direction, said extraction aperture having an extraction aperture height extending along said first direction, said extraction plate defining an inner surface aligned with said extraction aperture, said inner surface lying in a first plane; a beam blocker disposed over the extraction aperture and having an outer surface disposed in a second plane, different from the first plane, toward the inside of the extraction plate; 1. An extraction assembly comprising: the beam blocker overlaps with the extraction plate along a first edge of the extraction aperture by a first overlap distance and along a second edge of the extraction aperture by a second overlap distance to define a first extraction slit along the first edge of the extraction aperture and a second extraction slit along a second edge of the extraction aperture; the beam blocker comprising a first ridge disposed along a first end of the beam blocker and a second ridge disposed along a second end of the beam blocker; The extractor assembly further comprises a shim assembly, the shim assembly including a first set disposed between the extractor plate and the first ridge, and further including a second set disposed between the extractor plate and the second ridge.

7. 2. The extraction assembly of claim 1, wherein the extraction plate and the beam blocker are interoperable to extract a first ion beamlet from the first extraction slit and a second ion beamlet from the second extraction slit, the first ion beamlet and the second ion beamlet producing a beam angular spread of less than 10 degrees.

8. 8. The extraction assembly of claim 7, wherein the first ion beamlet and the second ion beamlet from the first extraction slit define a mean beam angle of less than 20 degrees relative to a normal to the first plane and the second plane.

9. a plasma chamber for containing the plasma; an extraction plate configured along a side of the plasma chamber, the extraction plate having an extraction aperture elongated along a second direction perpendicular to the first direction, the extraction aperture having an extraction aperture height extending along the second direction, the extraction plate defining an inner surface along the extraction aperture that lies in a first plane; a beam blocker disposed over the extraction aperture and having an outer surface disposed in a second plane, different from the first plane, toward the inside of the extraction plate; A processing device comprising: the beam blocker overlaps with the extraction plate along a first edge of the extraction aperture by a first overlap distance and along a second edge of the extraction aperture by a second overlap distance to define a first extraction slit along the first edge of the extraction aperture and a second extraction slit along a second edge of the extraction aperture; The processing apparatus wherein the extraction plate and the beam blocker comprise a dielectric material.

10. 10. The processing device of claim 9, wherein the first plane and the second plane define an extraction slit width for the first extraction slit and the second extraction slit, the extraction slit width being a separation distance between the first plane and the second plane along a normal to the first plane and the second plane.

11. A plasma chamber for containing the plasma; an extraction plate configured along a side of the plasma chamber, the extraction plate having an extraction aperture elongated along a second direction perpendicular to the first direction, the extraction aperture having an extraction aperture height extending along the second direction, the extraction plate defining an inner surface along the extraction aperture that lies in a first plane; a beam blocker disposed over the extraction aperture and having an outer surface disposed in a second plane, different from the first plane, toward the inside of the extraction plate; A processing device comprising: the beam blocker overlaps with the extraction plate along a first edge of the extraction aperture by a first overlap distance and along a second edge of the extraction aperture by a second overlap distance to define a first extraction slit along the first edge of the extraction aperture and a second extraction slit along a second edge of the extraction aperture; the first plane and the second plane define an extraction slit width for the first extraction slit and the second extraction slit, the extraction slit width being a separation distance between the first plane and the second plane along a normal to the first plane and the second plane; The processing device, wherein the first overlap distance and the second overlap distance are equal to 10% to 100% of the extraction slit width.

12. 11. The processing apparatus of claim 10, wherein the extraction slit width is equal to 5% to 40% of the extraction aperture height.

13. 10. The processing apparatus of claim 9, wherein the beam blocker comprises a first ridge disposed along a first end of the beam blocker and a second ridge disposed along a second end of the beam blocker.

14. A plasma chamber for containing the plasma; an extraction plate configured along a side of the plasma chamber, the extraction plate having an extraction aperture elongated along a second direction perpendicular to the first direction, the extraction aperture having an extraction aperture height extending along the second direction, the extraction plate defining an inner surface along the extraction aperture that lies in a first plane; a beam blocker disposed over the extraction aperture and having an outer surface disposed in a second plane, different from the first plane, toward the inside of the extraction plate; A processing device comprising: the beam blocker overlaps with the extraction plate along a first edge of the extraction aperture by a first overlap distance and along a second edge of the extraction aperture by a second overlap distance to define a first extraction slit along the first edge of the extraction aperture and a second extraction slit along a second edge of the extraction aperture; the beam blocker comprising a first ridge disposed along a first end of the beam blocker and a second ridge disposed along a second end of the beam blocker; the processing device further comprising a shim assembly, the shim assembly including a first set disposed between the extraction plate and the first ridge, and further including a second set disposed between the extraction plate and the second ridge.

15. 10. The processing apparatus of claim 9, wherein the extraction plate and the beam blocker are interoperable to extract a first ion beamlet from the first extraction slit and a second ion beamlet from the second extraction slit, the first ion beamlet and the second ion beamlet producing a beam angular spread of less than 10 degrees.

16. 16. The processing apparatus of claim 15, wherein the first ion beamlet and the second ion beamlet from the first extraction slit define a mean beam angle of less than 20 degrees relative to a normal to the first plane and the second plane.

17. a plasma chamber for containing the plasma; an extraction assembly positioned adjacent to the plasma chamber, an extraction plate configured along a side of the plasma chamber, the extraction plate having an extraction aperture elongated along a second direction perpendicular to the first direction, the extraction aperture having an aperture height extending along the second direction, the extraction plate defining an inner surface along the extraction aperture that lies in a first plane; a beam blocker disposed over the extraction aperture and having an outer surface disposed in a second plane, different from the first plane, toward an interior of the extraction plate; a coupling assembly reversibly coupling the beam blocker to the extraction plate; an extraction assembly comprising:

1. A compact angled ion beam device comprising: the coupling assembly is configured to adjust an overlap distance between the extraction plate and the beam blocker along the second direction and to adjust a slit width of the extraction assembly, the slit width comprising a distance between the extraction plate and the beam blocker along a third direction perpendicular to the first plane and the second plane; The beam blocker a first ridge disposed along a first end of the beam blocker and a second ridge disposed along a second end of the beam blocker; a shim assembly, the shim assembly including a first set disposed between the extraction plate and the first ridge, and further including a second set disposed between the extraction plate and the second ridge; 1. A compact angled ion beam device comprising:

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