Ion beam aperture control for ion beam substrate processing systems

Abstract

An ion beam processing system includes a plasma source configured to generate plasma. A grid assembly includes a first grid including a first plurality of through holes arranged within a first circular aperture, a second grid including a second plurality of through holes arranged within a second circular aperture, and a third grid including a third plurality of through holes arranged within a third circular aperture. An aperture shaping grid is arranged between the first grid and the plasma source and includes an aperture smaller than the first, second and third circular apertures. The aperture has a shape corresponding a profile of a substrate or a shape corresponding to a spatial plasma distribution, tilted at a predetermined angle relative to a plane transverse to an ion travel direction, projected onto the plane.

Description

ION BEAM APERTURE CONTROL FOR ION BEAM SUBSTRATE PROCESSING SYSTEMSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 553,539, filed on February 14, 2024 and U.S. Provisional Application No. 63 / 555,712, filed on February 20, 2024. The entire disclosures of each of the applications referenced above are incorporated herein by reference.FIELD

[0002] The present disclosure relates to ion beam substrate processing systems, and more particularly to ion beam aperture control for ion beam substrate processing systems.BACKGROUND

[0003] The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

[0004] Substrate processing systems may be used to treat substrates such as semiconductor wafers. The substrate treatments may include deposition, etching, cleaning, and other treatments. For example, substrate etching may be performed using an ion beam generated by a plasma source. A substrate is arranged on a substrate support in a processing chamber. The ions generated by the plasma source pass through aligned holes in a multi-layer grid assembly arranged between the plasma source and the processing chamber. The ions impact a substrate arranged on a substrate support.SUMMARY

[0005] An ion beam processing system includes a plasma source configured to generate plasma. A grid assembly includes a first grid including a first plurality of through holes arranged within a first circular aperture, a second grid including a second plurality of through holes arranged within a second circular aperture, and a third grid including a third plurality of through holes arranged within a third circular aperture. An apertureshaping grid is arranged between the first grid and the plasma source and including an aperture smaller than the first, second and third circular apertures. The aperture has a shape corresponding a profile of a substrate, tilted at a predetermined angle relative to a plane transverse to an ion travel direction, projected onto the plane.

[0006] In other features, a first voltage source is configured to supply a first voltage potential to the first grid. A second voltage source is configured to supply a second voltage potential to the second grid, wherein the third grid is grounded. The aperture has an elliptical shape. Upper and lower portions of the aperture are asymmetrical to compensate for ion beam dispersion. The first, second and third plurality of through holes are aligned.

[0007] In other features, the predetermined angle is in a range greater than or equal to 30Qand less than 90Q. The predetermined angle is in a range greater than or equal to 60Qand less than 90Q. The aperture shaping grid is configured to not partially block any of the first plurality of through holes in the first grid.

[0008] An ion beam processing system includes a plasma source configured to generate plasma. A grid assembly includes a first grid including a plurality of through holes arranged within a first aperture, a second grid including a plurality of through holes arranged within a second aperture, and a third grid including a plurality of through holes arranged within a third aperture. The first aperture has a non-circular shape, and wherein the non-circular shape of the first aperture corresponds to a profile of a substrate, tilted at a predetermined angle relative to a plane transverse to an ion travel direction, projected onto the plane.

[0009] In other features, a first voltage source is configured to supply a first voltage potential to the first grid. A second voltage source is configured to supply a second voltage potential to the second grid, wherein the third grid is grounded. The first aperture has an elliptical shape. Upper and lower sides of the first aperture are asymmetrical to compensate for ion beam dispersion. The predetermined angle is in a range greater than or equal to 30Qand less than 90Q.

[0010] In other features, the predetermined angle is in a range greater than or equal to 60Qand less than 90Q. At least two of the first aperture, the second aperture, and the third aperture have the non-circular shape. The first aperture, the second aperture, and the third aperture have the non-circular shape.

[0011] An ion beam processing system includes a plasma source configured to generate plasma. A grid assembly includes a first grid including a plurality of through holes arranged within a first circular aperture. A second grid includes a plurality of through holes arranged within a second circular aperture. A third grid includes a plurality of through holes arranged within a third circular aperture. A substrate support is configured to rotatably support a substrate. A rotational positioning device is configured to tilt the substrate support to a plurality of angles relative to a plane transverse to a direction of ion travel. First and second movable shutters are arranged one of upstream and downstream from the grid assembly and configured to move in a plane transverse to an ion travel direction to block a portion of an ion beam between the first circular aperture and a profile of a substrate, tilted at a predetermined angle relative to a plane transverse to an ion travel direction, projected onto the plane.

[0012] In other features, a first voltage source is configured to supply a first voltage potential to the first grid. A second voltage source is configured to supply a second voltage potential to the second grid, wherein the third grid is grounded. At least one of the plurality of angles is in a range greater than or equal to 30Qand less than 90Q. At least one of the plurality of angles is in a range greater than or equal to 60Qand less than 90Q. Facing surfaces of the first and second movable shutters are arcuate. Facing surfaces of the first movable shutter and the second movable shutter include first and second arcuate surfaces matching the profile of the substrate tilted to one of the plurality of angles. Facing surfaces of the first movable shutter and the second movable shutter are asymmetrical to compensate for ion beam dispersion.

[0013] In other features, the first and second movable shutters are arranged upstream from the grid assembly.

[0014] An ion beam processing system includes a plasma source configured to generate plasma. A grid assembly includes a first grid including a plurality of through holes arranged within a first circular aperture. A second grid includes a plurality of through holes arranged within a second circular aperture. A third grid includes a plurality of through holes arranged within a third circular aperture. A substrate support is configured to support a substrate at a predetermined angle relative to a plane transverse to a direction of ion travel. First and second fixed shutters are arranged one of upstream and downstream from the grid assembly and configured to block portions of an ion beambetween the first circular aperture and a profile of the substrate, tilted at the predetermined angle, projected onto the plane.

[0015] In other features, a first voltage source is configured to supply a first voltage potential to the first grid. A second voltage source is configured to supply a second voltage potential to the second grid, wherein the third grid is grounded. The predetermined angle is in a range greater than or equal to 30Qand less than 90Q. The predetermined angle is in a range greater than or equal to 60Qand less than 90Q. The first and second fixed shutters are arranged upstream from the grid assembly. Facing surfaces of the first and second fixed shutters are arcuate. Facing surfaces of the first and second fixed shutters are asymmetrical to compensate for ion beam dispersion.

[0016] An ion beam processing system includes a plasma source configured to generate plasma, a substrate support configured to support a substrate and tilt at a predetermined angle relative to a plane transverse to a travel direction of the ion beam projected onto the plane, a grid assembly, and an aperture shaping grid. The grid assembly includes a first grid including a first plurality of through holes arranged within a first circular aperture, a second grid including a second plurality of through holes arranged within a second circular aperture, and a third grid including a third plurality of through holes arranged within a third circular aperture. The aperture shaping grid is arranged between the first grid and the plasma source and includes an aperture smaller than the first, second and third circular apertures.

[0017] In other features, the aperture has a shape corresponding to a spatial plasma distribution.

[0018] In other features, the aperture has an irregular shape or an elliptical shape.

[0019] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0021] FIGS. 1A to 1 C are functional block diagrams of an example of an ion beam processing system including a shutter in open and closed positions and / or a tilted substrate support;

[0022] FIG. 2A is an exploded perspective view of a grid assembly and an aperture shaping grid according to the present disclosure;

[0023] FIG. 2B is a plan view of the grid assembly and the aperture shaping grid according to the present disclosure;

[0024] FIG. 2C is a partial side cross sectional view of the grid assembly and the aperture shaping grid according to the present disclosure;

[0025] FIGS. 3A and 3B are exploded perspective views of examples of a grid assembly including one or more grids having a reduced aperture according to the present disclosure;

[0026] FIGS. 3C and 3D are plan views illustrating different shapes for the reduced aperture according to the present disclosure;

[0027] FIGS. 4A-B are plan views of aperture shaping grids employable with a grid assembly, where the aperture shaping grids include apertures having irregular shapes according to the present disclosure;

[0028] FIG. 5 is a functional block diagram of an example of an ion beam processing system including first and second fixed shutters configured to restrict the ion beam for a predetermined tilt angle of the substrate support according to the present disclosure;

[0029] FIGS. 6A to 6D are functional block diagrams of an example of an ion beam processing system including first and second movable shutters configured to restrict the ion beam for different tilt angles of the substrate support according to the present disclosure;

[0030] FIG. 7 is a flowchart of a method for operating the ion beam processing system of FIGS. 6A to 6D; and

[0031] FIGS. 8A to 8E are plan views illustrating positioning of shutters having arcuate facing surfaces in various positions according to the present disclosure.

[0032] In the drawings, reference numbers may be reused to identify similar and / or identical elements.DETAILED DESCRIPTION

[0033] The present disclosure relates to ion beam aperture control for ion beam processing systems. A grid assembly including multiple parallel grids is arranged between a plasma source and a processing chamber. The plasma source and the grid assembly are typically designed for ion beam processing with the substrate arranged parallel to and spaced from parallel planes through the grids of the grid assembly. The grids include a pattern of through holes within circular apertures having diameters approximately the same as the diameter of the substrate when oriented parallel to the grids.

[0034] In some examples, the substrate support is tilted at an angle relative to the planes through the grids of the grid assembly to enhance the effect of the ions bombarding the substrate. For example, the substrate support may be tilted at a relatively high angle (e.g., greater than 30Q(e.g., 60Q, 70Q, 80Qor higher) relative to a direction transverse to the ion travel direction.

[0035] At higher tilt angles, the ion beam width generated by the circular aperture is larger than a profile of the substrate projected onto a plane parallel to and spaced from the planes through the grids of the grid assembly. As a result, some of the ions in the ion beam pass through the grid assembly, miss the substrate and impact a side of the substrate support and / or an inner surface of the processing chamber. The ions sputter material from sides of the substrate support and / or the inner surfaces of the processing chamber. The sputtered material may be deposited onto the substrate causing substrate defects.

[0036] In other examples, an aperture shaping grid is arranged over the grid assembly. The aperture shaping grid includes a reduced ion beam aperture that has a shape corresponding to a profile of the substrate (when the substrate is tilted at a predetermined angle relative to a plane including the aperture shaping grid) projected onto the plane. The aperture shaping grid prevents / reduces ions from impacting the side surface of the substrate support and / or the inner surface of the processing chamber. Areas inside of the reduced aperture include a pattern of through holes (aligned with holes in the grid assembly) while areas outside of the reduced aperture do not.

[0037] In other examples, the aperture shaping grid includes a reduced ion beam aperture that has a shape corresponding to a spatial plasma distribution. In such examples, the spatial plasma distribution refers to how the density and othercharacteristics or properties (e.g., temperature, potential, etc.) of plasma from the plasma source vary across different locations within a given space. In such examples, the spatial plasma distribution may represent where the plasma is most concentrated and how characteristics or properties of the plasma change depending on position within that space. In various embodiments, the reduced ion beam aperture may have an irregular shape, an elliptical shape, or any other suitable shape depending on the spatial plasma distribution.

[0038] In other examples, one or more grids of the grid assembly include a reduced aperture (e.g., smaller than a diameter of the circular aperture typically equal to the substrate diameter). The reduced aperture has a shape corresponding a profile of the substrate (when the substrate is tilted at a predetermined angle relative to a plane including the grid with the reduced diameter) projected onto the plane. The reduced aperture reduces / prevents ions from impacting the side surfaces of the substrate support and / or the inner surfaces of the processing chamber. In other examples, first and second fixed shutters are used to block ions when the substrate is tilted at or around a predetermined tilt angle to reduce / prevent ions from impacting the side surface of the substrate support and / or the inner surface of the processing chamber.

[0039] In other examples, first and second moveable shutters are arranged before or after the grid assembly to variably reduce the ion beam aperture and block ions when the substrate is tilted at different tilt angles to reduce / prevent ions from impacting the side surface of the substrate support and / or the inner surface of the processing chamber.

[0040] Referring now to FIG. 1 , an ion beam processing system 50 for substrates includes a plasma source 60. While a specific type of plasma source using inductively coupled plasma (ICP) is shown, other plasma sources may be used. In this example, the plasma source 60 generates plasma in an enclosure 61 that contains the plasma during operation. The plasma source 60 includes a gas distribution device 62 configured to deliver and distribute a plasma gas mixture in the enclosure 61 . In some examples, the gas distribution device 62 includes a gas plenum 63 and a plurality of gas through holes 65 extending through a surface of the gas plenum 63. In other examples, the gas distribution device 62 includes one or more gas injectors.

[0041] One or more inductive coils 64 are arranged around an outer surface of the enclosure 61 . RF power is supplied to the one or more inductive coils 64. When the plasma gas mixture is supplied and the inductive coils are energized, the inductive coils64 induce a magnetic field inside of the enclosure 61 that strikes and maintains the plasma. A grid assembly 66 including one or more grids 67 with a pattern of aligned through holes 69 is arranged between the plasma source 60 and a processing chamber 70. In some examples, the grid assembly 66 includes three grids that are arranged in parallel planes spaced from one another. A substrate support 86 is arranged in the processing chamber 70. The ions pass through the aligned through holes 69 in the grids 67 of the grid assembly 66 and impact a substrate 84 arranged on the substrate support 86.

[0042] In some examples, the grid assembly 66 includes a first grid 87-1 that is connected to a voltage source 81 , a second grid 87-2 that is connected to a voltage source 82, and a third grid 87-3 that is grounded. In some examples, the voltage source 81 operates in a range from 100V to 1000V and the voltage source 82 operates in a range from -100V to -1000V. The voltage sources 81 and 82 accelerate the ions generated by the plasma towards the substrate 84.

[0043] In some examples, a rotational positioning device 78 is configured to tilt the substrate support 86 in the processing chamber 70. A surface 80 of the substrate support 86 is configured to support and / or engage the substrate 84 such as a semiconductor wafer during substrate treatment (such as during etching). For example, the substrate support 86 may be an electrostatic chuck.

[0044] A gas delivery system 90 and the gas distribution device 62 deliver a plasma gas mixture including to the processing chamber 70. A coil driving circuit 94 (and optionally a matching circuit (not shown) supplies RF power to the one or more inductive coils 64. A controller 96 may be used to control the rotational positioning device 78, the substrate support 86, the coil driving circuit 94, the gas delivery system 90, and / or other components of the ion beam processing system 50.

[0045] During operation, the gas delivery system 90 and the gas distribution device 62 deliver the plasma gas mixture to the enclosure 61 . The coil driving circuit 94 outputs RF power to the one or more inductive coils 64 to induce a magnetic field inside of the enclosure 61. The induced magnetic field strikes and maintains plasma 91 in the enclosure 61. The plasma 91 produces an ion beam 97 including ions. The ions of the ion beam 97 pass through the through holes 69 inside of the aperture in the grid assembly 66 and impact an exposed surface of the substrate 84.

[0046] In FIG. 1 A, a shutter actuator 76 moves a shutter 74 to a first or closed position to block the ion beam. When ready for processing, the shutter 74 is moved to a second or open position to allow an ion beam 98 to reach the substrate 84 as shown in FIG. 1 B. As shown in FIGS. 1 A and 1 B, the substrate support 86 can be arranged transverse to the ion beam during ion beam processing. As shown in FIG. 1 C, the rotational positioning device 78 may tilt the substrate support 86 to one or more predetermined tilt angles relative to the transverse direction shown in FIGS. 1 A and 1 B. Alternately, the rotational positioning device 78 can be omitted and the tilt angle of the substrate support can be set manually.

[0047] As can be seen in FIG. 1 C, when the substrate is positioned at the predetermined tilt angle, the ion beam 98 is wider than a projected profile of the substrate support 86 in the tilted position. As a result, some of the ions in the ion beam pass by the substrate and impact sides of the substrate support 86 and / or inner surfaces of the processing chamber 70 behind the substrate support 86. In other words, the ions impact areas other than the substrate 84. The ions cause wear / damage to the substrate support 86 and / or the inner surface of the processing chamber 70. In addition, the ions cause sputtering sides of the substrate support 86 and / or the inner surfaces of the processing chamber 70. For example, when the sides of the substrate support and / or the inner surfaces of the processing chamber 70 are made of stainless steel, iron (Fe) may be sputtered onto the substrate. The sputtered material causes substrate defects.

[0048] Referring now to FIGS. 2A to 2C, a grid assembly 100 includes a first grid 120 including a pattern of through holes 124 within a first circular aperture. The grid assembly 100 includes a second grid 130 including a pattern of through holes 134 within a second circular aperture. The grid assembly 100 includes a third grid 140 including a pattern of through holes 144 within a third circular aperture. The first, second and third apertures are approximately equal to the diameter of the substrate when the substrate is parallel to planes through the grids of the grid assembly 100. The holes 124, 134, and 144 are aligned to allow ions to pass through the grid assembly 100. The first, second and third circular apertures are also aligned.

[0049] The grid assembly 100 includes an insulating ring 150 including a circular opening 154 and a support ring 160 including a circular opening 164. In some examples, the circular openings 154 and 164 have a diameter that is larger than the first, second and third apertures surrounding the pattern of through holes 124, 134, and 144 of the firstgrid 120, the second grid 130, and the third grid 140, respectively. In some examples, the insulating ring 150 is made of ceramic and the support ring 160 is made of stainless steel, although other materials can be used.

[0050] In some examples, the through holes have the same diameter and uniform spacing. In other examples, the through holes have the same diameter and variable spacing to improve the uniformity of the ion beam density with increasing radial distance. For example, the through holes are spaced more closely together as a radial distance from a center of the grid increases to compensate for falloff in ion beam density. In other examples, the through holes are spaced uniformly but have different diameters to compensate for falloff in ion beam density with increasing radial distance. For example, the through holes are larger as the radial distance from the center of the grid increases to compensate for falloff in ion beam density.

[0051] An aperture shaping grid 170 includes an aperture 174. In some examples, the aperture 174 is a completely open space. In other examples, the aperture 174 includes a pattern of through holes 175 arranged therein. The through holes 175 are aligned with and have the same diameter as the corresponding through holes in the grid assembly 10O.The aperture shaping grid 170 does not include through holes outside of the aperture 174. The aperture 174 has outer dimensions that are smaller than the first, second and third apertures of the pattern of through holes 124, 134, and 144 in the first grid 120, the second grid 130, and the third grid 140, respectively. The aperture 174 has a shape and size that corresponds to the projected profile of the substrate 84 when the substrate support is tilted.

[0052] In FIG. 2C, the aperture shaping grid 170 blocks the through holes in the first grid 120, the second grid 130, and the third grid 140 that are located outside of the aperture 174 of the aperture shaping grid 170. The aperture shaping grid 170 is designed such that it does not partially block any of the through holes 124, 134, and 144 in the first grid 120, the second grid 130, and the third grid 140. As can be appreciated, partially blocking the through holes with the aperture shaping grid 170 may alter a meniscus 171 of the plasma and may cause ions to travel at different / increased angles (as shown at 173) that may undesirably impact the side of the substrate support 86 or the inner surface of the processing chamber 70.

[0053] Referring now to FIGS. 3A to 3D, a grid assembly 200 includes a first grid 220 including a pattern of through holes 224 arranged within a first aperture. The gridassembly 200 includes a second grid 230 including a pattern of through holes 234 arranged within a second aperture. The grid assembly 200 includes a third grid 240 including a pattern of through holes 244 arranged within a third aperture. The grid assembly 200 includes an insulating ring 250 including a circular opening 254 and a support ring 260 including a circular opening 264. The circular openings 254 and 264 are equal to or larger than the apertures of the first grid 220, the second grid 230, and the third grid 240.

[0054] In FIG. 3A, the aperture of the pattern of through holes 224 is smaller than the circular apertures surrounding the through holes 234 and 244 of the second and third grids 230 and 240, respectively. The aperture of the pattern of through holes 224 has a size and shape corresponding to the projected profile of the substrate when the substrate support is tilted at a predetermined angle. In FIG. 3B, the apertures of the pattern of through holes 224, 234 and 244 of the first, second, and third grids 220, 230, and 240 have a size and shape corresponding to the elliptical projected profile of the substrate when the substrate support is tilted at a predetermined angle or a range of angles. In FIG. 3C, the aperture of the pattern of through holes 224 has an elliptical shape. In FIG. 3D, the aperture of the pattern of through holes 224 has an asymmetrical arcuate shape (e.g., a modified ellipse) to account for ion beam spreading between a leading edge and a trailing edge of the substrate support when tilted.

[0055] In other embodiments, apertures of the aperture shaping grids herein may have a shape and size that corresponds to a spatial plasma distribution rather than a projected profile of the substrate. For instance, when a substrate support is tilted, an aperture of an aperture shaping grid may have an irregular shape or a regular shape (e.g., an elliptical shape, etc.) that corresponds to a spatial plasma distribution. In other words, the shape and size of the aperture may depend on the density and other characteristics or properties (e.g., temperature, potential, etc.) of plasma provided by a plasma source (e.g., the plasma source 60 of FIG. 1 ) across different locations within a given space. In such examples, an irregular shape refers to a non-traditional shape that may change from one substrate processing chamber setup to another substrate processing chamber setup based on a spatial plasma distribution of each setup. In various embodiments, the irregular-shaped aperture may have sides of different lengths (e.g., one or more sides may have different lengths).

[0056] For example, FIGS. 4A-B illustrates aperture shaping grids 270A, 270B each employable with a grid assembly, such as any one of the grid assemblies herein. As shown in FIGS. 4A-B, each aperture shaping grid 270A, 270B includes an aperture 274A, 274B. In some examples, each aperture 274A, 274B is a completely open space as shown in FIGS. 4A-B. In other examples, any one or both apertures 274A, 274B may include a pattern of through holes arranged therein, similar to the example aperture 174 of FIG. 2B. If through holes are employed, the through holes may be aligned with and have the same diameter as corresponding through holes in the grid assembly. Additionally, the aperture shaping grids 270A, 270B do not include through holes outside of the apertures 274A, 274B. In various embodiments, the apertures 274A, 274B have outer dimensions that are smaller than apertures of other grids (not shown) in the grid assembly.

[0057] As shown, the apertures 274A, 274B have an irregular shape and size. In this example, the shape and size of each aperture 274A, 274B corresponds to a spatial plasma distribution as explained herein. In various examples, the irregular shape of each aperture 274A, 274B may be a similar shape as the aperture 174 of the aperture shaping grid 170 in FIG. 2B, but with additional area (e.g., additional open space). For instance, the additional area for the aperture 274A is generally near outer opposing regions (e.g., vertices) associated with a major, horizontal axis of the aperture 274A, and the additional area for the aperture 274B is generally near outer opposing regions (e.g., vertices) associated with a horizontal axis and a vertical axis of the aperture 274B. While the example apertures 274A, 274B of FIGS. 4A-B are shown as having particular irregular shapes, it should be appreciated that the apertures may have different irregular or regular shapes depending on a spatial plasma distribution as explained herein.

[0058] Referring now to FIG. 5, an ion beam processing system 300 includes first and second fixed shutters 310-1 and 310-2 that are positioned upstream or downstream from the grid assembly to produce a narrowed ion beam 98’ corresponding to a predetermined tilt angle of the substrate support (or a relatively narrow range of predetermined tilt angles).

[0059] Referring now to FIGS. 6A to 6D, an ion beam processing system 400 includes first and second movable shutters 410-1 and 410-2 that are positioned upstream or downstream from the grid assembly. The first and second moveable shutters 410-1 and 410-2 are positioned by shutter actuators 420-1 and 420-2 to selectively narrow the ionbeam for a plurality of tilt angles of the substrate support 86. In FIG. 6A, the first and second moveable shutters 410-1 and 410-2 are fully closed. In FIG. 6B, the first and second moveable shutters 410-1 and 410-2 are fully opened and the ion beam has a widest width. This position may be used when the substrate is arranged at zero or low tilt angles relative to a plane parallel to planes through the grids.

[0060] In FIG. 6C, the first and second moveable shutters 410-1 and 410-2 are partially closed to a first position corresponding to a first tilt angle. In FIG. 6D, the first and second moveable shutters 410-1 and 410-2 are partially closed to a second position corresponding to a second tilt angle higher than the first tilt angle. As can be appreciated, additional tilt angles and shutter positions can be used to minimize ions bombarding the sides surfaces of the substrate support and / or inner surfaces of the processing chamber.

[0061] Referring now to FIG. 7, a method 500 for controlling an ion beam aperture is shown. At 510, the method determines whether ion beam processing is to be started. At 518, the desired tilt angle of the substrate support is determined. At 522, positions of the first and second moveable shutters are determined based on the desired tilt angle. For example, a table indexed by the desired tilt angle can be used to provide positions of the first and second moveable shutters.

[0062] At 524, the substrate support is tilted to the desired tilt angle. At 526, plasma is struck. At 528, the first and second shutters are opened to positions corresponding to the desired tilt angle. At 530, the method determines whether ion beam processing for the substrate is done. If 530 is true, the method continues at 532 and extinguishes the plasma. If 530 is false, the method returns to 530.

[0063] Referring now to FIGS. 8A to 8E, the shutters include an arcuate inner surface to match outer edges of the profile corresponding to the tilted substrate. In FIG. 8A, first and second shutters 610-1 and 610-2 are fully closed. In some examples, the first and second shutters 610-1 and 610-2 include substrate facing surfaces 614-1 and 614-2 that are arcuate surfaces. In some examples, the curvatures of the arcuate surfaces of the first and second substrate facing surfaces 614-1 and 614-2 match the curvature of a substrate profile 616 at one of the angles (e.g., a minimum angle, a middle one of the angles, or a maximum angle). In some examples, the curvatures of the arcuate surfaces of the first and second substrate facing surfaces 614-1 and 614-2 match the curvature of a substrate profile 616 at an angle a1 (or substrate profile 616-a1 ) corresponding to a maximum supported tilt angle (e.g., angle a1).

[0064] As can be seen in FIG. 8A, a circular aperture 622 is defined to form an outer boundary for ions. In this position, ions travelling between the circular aperture and the outer edges of the substrate profile 616-a1 are blocked by the shutters 610-1 and 610-2. As a result, the ions do not sputter material from inner surfaces of the processing chamber or a side surfaces of the substrate support.

[0065] In FIGS. 8B to 8E, the substrate profile 616 is tilted to increasing angles a2, a3, a4, and a5. Angle a5 corresponds to zero tilt angle (or parallel to a plane perpendicular to the direction of ion travel). As can be seen in FIGS. 8B to 8D, the arcuate surfaces of the first and second substrate facing surfaces 614-1 and 614-2 are shown with substrate angles a2, a3, and a4. The arcuate surfaces of the first and second substrate facing surfaces 614-1 and 614-2 help to minimize ions that pass between the circular aperture 622 and the tilted substrate profile projected onto a plane perpendicular to a direction of ion travel. The reduced number of ions sputter less material from surfaces of the processing chamber or a backside of the substrate support, which reduces defects.

[0066] In some examples, the same beam grid potential from the voltage source 81 can be applied to the apertures to minimize disturbance to the plasma. In some examples, the grids and the aperture can be made of molybdenum (Mo) or other suitable metallic materials with similar coefficients of thermal expansion.

[0067] The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and / or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure.

[0068] Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms,including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

[0069] In some implementations, a controller is part of a system, which may be part of the above-described examples. Such systems can comprise semiconductor processing equipment, including a processing tool or tools, chamber or chambers, a platform, or platforms for processing, and / or specific processing components (a wafer pedestal, a gas flow system, etc.). These systems may be integrated with electronics for controlling their operation before, during, and after processing of a semiconductor wafer or substrate. The electronics may be referred to as the “controller,” which may control various components or subparts of the system or systems. The controller, depending on the processing requirements and / or the type of system, may be programmed to control any of the processes disclosed herein, including the delivery of processing gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, positional and operation settings, wafer transfers into and out of a tool and other transfer tools and / or load locks connected to or interfaced with a specific system.

[0070] Broadly speaking, the controller may be defined as electronics having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and / or one or more microprocessors, or microcontrollers that execute program instructions (e.g., software). Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files), defining operational parameters for carrying out a particular process on or for a semiconductor wafer or to a system. The operationalparameters may, in some embodiments, be part of a recipe defined by process engineers to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0071] The controller, in some implementations, may be a part of or coupled to a computer that is integrated with the system, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the “cloud” or all or a part of a fab host computer system, which can allow for remote access of the wafer processing. The computer may enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from a plurality of fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process. In some examples, a remote computer (e.g., a server) can provide process recipes to a system over a network, which may include a local network or the Internet. The remote computer may include a user interface that enables entry or programming of parameters and / or settings, which are then communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of data, which specify parameters for each of the processing steps to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process to be performed and the type of tool that the controller is configured to interface with or control. Thus, as described above, the controller may be distributed, such as by comprising one or more discrete controllers that are networked together and working towards a common purpose, such as the processes and controls described herein. An example of a distributed controller for such purposes would be one or more integrated circuits on a chamber in communication with one or more integrated circuits located remotely (such as at the platform level or as part of a remote computer) that combine to control a process on the chamber.

[0072] Without limitation, example systems may include a plasma etch chamber or module, a deposition chamber or module, a spin-rinse chamber or module, a metal plating chamber or module, a clean chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing systemsthat may be associated or used in the fabrication and / or manufacturing of semiconductor wafers.

[0073] As noted above, depending on the process step or steps to be performed by the tool, the controller might communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, or tools used in material transport that bring containers of wafers to and from tool locations and / or load ports in a semiconductor manufacturing factory.

Claims

CLAIMSWhat is claimed is:1 . An ion beam processing system, comprising: a plasma source configured to generate plasma; a grid assembly comprising: a first grid including a first plurality of through holes arranged within a first circular aperture; a second grid including a second plurality of through holes arranged within a second circular aperture; and a third grid including a third plurality of through holes arranged within a third circular aperture; and an aperture shaping grid arranged between the first grid and the plasma source and including an aperture smaller than the first, second and third circular apertures, wherein the aperture has a shape corresponding a profile of a substrate, tilted at a predetermined angle relative to a plane transverse to an ion travel direction, projected onto the plane.

2. The ion beam processing system of claim 1 , further comprising: a first voltage source configured to supply a first voltage potential to the first grid; and a second voltage source configured to supply a second voltage potential to the second grid, wherein the third grid is grounded.

3. The ion beam processing system of claim 1 , wherein the aperture has an elliptical shape.

4. The ion beam processing system of claim 1 , wherein upper and lower portions of the aperture are asymmetrical to compensate for ion beam dispersion.

5. The ion beam processing system of claim 1 , wherein the first, second and third plurality of through holes are aligned.

6. The ion beam processing system of claim 1 , wherein the predetermined angle is in a range greater than or equal to 30Qand less than 90Q.

7. The ion beam processing system of claim 1 , wherein the predetermined angle is in a range greater than or equal to 60Qand less than 90Q.

8. The ion beam processing system of claim 1 , wherein the aperture shaping grid is configured to not partially block any of the first plurality of through holes in the first grid.

9. An ion beam processing system, comprising: a plasma source configured to generate plasma; and a grid assembly comprising: a first grid including a plurality of through holes arranged within a first aperture; a second grid including a plurality of through holes arranged within a second aperture; and a third grid including a plurality of through holes arranged within a third aperture, wherein the first aperture has a non-circular shape, and wherein the noncircular shape of the first aperture corresponds to a profile of a substrate, tilted at a predetermined angle relative to a plane transverse to an ion travel direction, projected onto the plane.

10. The ion beam processing system of claim 9, further comprising: a first voltage source configured to supply a first voltage potential to the first grid; and a second voltage source configured to supply a second voltage potential to the second grid, wherein the third grid is grounded.11 . The ion beam processing system of claim 9, wherein the first aperture has an elliptical shape.

12. The ion beam processing system of claim 9, wherein upper and lower sides of the first aperture are asymmetrical to compensate for ion beam dispersion.

13. The ion beam processing system of claim 9, wherein the predetermined angle is in a range greater than or equal to 30Qand less than 90Q.

14. The ion beam processing system of claim 9, wherein the predetermined angle is in a range greater than or equal to 60Qand less than 90Q.

15. The ion beam processing system of claim 9, wherein at least two of the first aperture, the second aperture, and the third aperture have the non-circular shape.

16. The ion beam processing system of claim 9, wherein the first aperture, the second aperture, and the third aperture have the non-circular shape.

17. An ion beam processing system, comprising: a plasma source configured to generate plasma; a grid assembly comprising: a first grid including a plurality of through holes arranged within a first circular aperture; a second grid including a plurality of through holes arranged within a second circular aperture; and a third grid including a plurality of through holes arranged within a third circular aperture; a substrate support configured to rotatably support a substrate; a rotational positioning device configured to tilt the substrate support to a plurality of angles relative to a plane transverse to a direction of ion travel; and first and second movable shutters arranged one of upstream and downstream from the grid assembly and configured to move in a plane transverse to an ion travel direction to block a portion of an ion beam between the first circular aperture and a profile of a substrate, tilted at a predetermined angle relative to a plane transverse to an ion travel direction, projected onto the plane.

18. The ion beam processing system of claim 17, further comprising: a first voltage source configured to supply a first voltage potential to the first grid; and a second voltage source configured to supply a second voltage potential to the second grid, wherein the third grid is grounded.

19. The ion beam processing system of claim 17, wherein at least one of the plurality of angles is in a range greater than or equal to 30Qand less than 90Q.

20. The ion beam processing system of claim 17, wherein at least one of the plurality of angles is in a range greater than or equal to 60Qand less than 90Q.21 . The ion beam processing system of claim 17, wherein facing surfaces of the first and second movable shutters are arcuate.

22. The ion beam processing system of claim 17, wherein facing surfaces of the first movable shutter and the second movable shutter include first and second arcuate surfaces matching the profile of the substrate tilted to one of the plurality of angles.

23. The ion beam processing system of claim 17, wherein facing surfaces of the first movable shutter and the second movable shutter are asymmetrical to compensate for ion beam dispersion.

24. The ion beam processing system of claim 17, wherein the first and second movable shutters are arranged upstream from the grid assembly.

25. An ion beam processing system, comprising: a plasma source configured to generate plasma; a grid assembly comprising: a first grid including a plurality of through holes arranged within a first circular aperture; a second grid including a plurality of through holes arranged within a second circular aperture; and a third grid including a plurality of through holes arranged within a third circular aperture; a substrate support configured to support a substrate at a predetermined angle relative to a plane transverse to a direction of ion travel; and first and second fixed shutters arranged one of upstream and downstream from the grid assembly and configured to block portions of an ion beam between the first circular aperture and a profile of the substrate, tilted at the predetermined angle, projected onto the plane.

26. The ion beam processing system of claim 25, further comprising: a first voltage source configured to supply a first voltage potential to the first grid; and a second voltage source configured to supply a second voltage potential to the second grid, wherein the third grid is grounded.

27. The ion beam processing system of claim 26, wherein the predetermined angle is in a range greater than or equal to 30Qand less than 90Q.

28. The ion beam processing system of claim 26, wherein the predetermined angle is in a range greater than or equal to 60Qand less than 90Q.

29. The ion beam processing system of claim 26, wherein the first and second fixed shutters are arranged upstream from the grid assembly.

30. The ion beam processing system of claim 26, wherein facing surfaces of the first and second fixed shutters are arcuate.31 . The ion beam processing system of claim 26, wherein facing surfaces of the first and second fixed shutters are asymmetrical to compensate for ion beam dispersion.

32. An ion beam processing system, comprising: a plasma source configured to generate plasma producing an ion beam; a substrate support configured to support a substrate and tilt at a predetermined angle relative to a plane transverse to a travel direction of the ion beam projected onto the plane; a grid assembly comprising: a first grid including a first plurality of through holes arranged within a first circular aperture; a second grid including a second plurality of through holes arranged within a second circular aperture; and a third grid including a third plurality of through holes arranged within a third circular aperture; and an aperture shaping grid arranged between the first grid and the plasma source and including an aperture smaller than the first, second and third circular apertures,33. The ion beam processing system of claim 32, wherein the aperture has an irregular shape.

34. The ion beam processing system of claim 32, wherein the aperture has a shape corresponding to a spatial plasma distribution.

35. The ion beam processing system of claim 32, wherein the aperture has an elliptical shape.

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