Bidirectional ion beam etching at high tilt angle for modifying sidewalls of line features

Abstract

An ion beam processing system includes a plasma source configured to generate plasma. A processing chamber includes a substrate support configured to support a substrate including line features including a top surface and side walls. A grid assembly is arranged between the plasma source and the processing chamber including aligned through holes configured to pass ions generated by the plasma to form an ion beam having an ion beam direction. A positioning device is configured to rotationally tilt the substrate support at a first predetermined tilt angle relative to the ion beam direction. The first predetermined tilt angle is in a range from 40º to 88º. The ion beam etches the side walls of the line features.

Description

BIDIRECTIONAL ION BEAM ETCHING AT HIGH TILT ANGLE FOR MODIFYING SIDEWALLS OF LINE FEATURESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 553,961 , filed on February 15, 2024. The entire disclosure of the application referenced above is incorporated herein by reference.FIELD

[0002] The present disclosure relates to ion beam substrate processing systems, and more particularly to bidirectional ion beam etching at a high tilt angle for modifying sidewalls of line features.'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 / or 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 processing chamber includes a substrate support configured to support a substrate including line features including a top surface and side walls. A grid assembly is arranged between the plasma source and the processing chamber including aligned through holes configured to pass ions generated by the plasma to form an ion beam having an ion beam direction. A positioning device is configured to rotationally tiltthe substrate support at a first predetermined tilt angle relative to the ion beam direction. The first predetermined tilt angle is in a range from 40Qto 88Q. The ion beam etches the side walls of the line features.

[0006] In other features, the ion beam etches the side walls of the line features from a first direction, and the positioning device at least one of rotates and tilts the substrate support to allow ion beam etching of the side walls of the line features in a second direction opposite to the first direction. The positioning device is configured to rotationally align the line features relative to the ion beam direction.

[0007] In other features, the positioning device is configured to rotationally align the line features at a first offset angle relative to the ion beam direction for ion beam etching one side of the side walls of the line features. The positioning device is configured to rotationally align the line features at a second offset angle relative to the ion beam direction for ion beam etching an opposite side of the side walls of the line features.

[0008] In other features, the first offset angle and the second offset angle are in a range from 0.5Qto 5Qof the ion beam direction. The first offset angle and the second offset angle are equal in magnitude and opposite in polarity. First and second voltage sources are configured to generate a predetermined beam voltage across at least two grids of the grid assembly. The first and second voltage sources are configured to generate a first predetermined beam voltage during a first period of ion beam etching of the substrate and a second predetermined beam voltage during a second period of ion beam etching of the substrate. The first predetermined beam voltage is different than the second predetermined beam voltage.

[0009] In other features, a pressure in the processing chamber is in a range from 0.3mT to 0.5mT during ion beam etching. The first predetermined tilt angle is in a range from 70Qto 88Q.

[0010] A method for ion beam etching line features of a substrate includes arranging a substrate including line features including a top surface and side walls on a substrate support in a processing chamber; tilting the substrate support at a first predetermined tilt angle; and generating an ion beam at the substrate support. The substrate support is tilted at the first predetermined tilt angle relative to an ion beam direction and the first predetermined tilt angle is in a range from 40Qto 88Q. The method includes etching the side walls of the line features using the ion beam.

[0011] In other features, etching the side walls of the line features using the ion beam includes etching the side walls of the line features from a first direction with the substrate support tilted at the first predetermined tilt angle, at least one of rotating and tilting the substrate support to allow ion beam etching of the side walls of the line features from a second direction with the substrate support tilted at the first predetermined tilt angle, wherein the second direction is opposite to the first direction.

[0012] In other features, the method includes rotationally aligning the line features relative to the ion beam direction. The method includes aligning the line features at a first offset angle relative to the ion beam direction for ion beam etching one side of the side walls of the line features, and aligning the line features at a second offset angle relative to the ion beam direction for ion beam etching an opposite side of the side walls of the line features.

[0013] In other features, the first offset angle and the second offset angle are in a range from 0.5Qto 5Qof the ion beam direction. The first offset angle and the second offset angle are equal in magnitude and opposite in polarity.

[0014] In other features, the method includes generating a first predetermined beam voltage during a first period of ion beam etching of the substrate; and generating a second predetermined beam voltage during a second period of ion beam etching of the substrate, wherein the first predetermined beam voltage is different than the second predetermined beam voltage.

[0015] In other features, a pressure in the processing chamber is in a range from 0.3mT to 0.5mT during ion beam etching. The first predetermined tilt angle is in a range from 70Qto 88Q.

[0016] 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

[0017] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0018] FIGS. 1A to 1 C are functional block diagrams of an example of an ion beam processing system including a substrate support arranged perpendicular to the ion beamdirection and tilted at opposite angles relative to the ion beam direction according to the present disclosure;

[0019] FIGS. 1 D and 1 E are perspective views of an example of a substrate including line features with side walls before and after bidirectional ion beam etching at a high tilt angle to reduce sidewall roughness according to the present disclosure;

[0020] FIG. 1 F is a graph illustrating an example of power spectral density of line width roughness as a function of frequency before and after ion beam etching according to the present disclosure;

[0021] FIG. 2A is a plan view of an example of a substrate including line features;

[0022] FIG. 2B is an enlarged side cross section of an example of the line features of the substrate;

[0023] FIG. 2C illustrates an example of determination of an offset angle D of the substrate support relative to the ion beam direction according to the present disclosure;

[0024] FIG. 3A is a side view illustrating an example of ion bombardment of the line features of the substrate to reduce sidewall roughness according to the present disclosure;

[0025] FIG. 3B is a graph illustrating an example of reduction in sidewall roughness as a function of tilt angle of the substate support according to the present disclosure;

[0026] FIG. 3C is a graph illustrating an example of loss on a top surface of the line features as a function of tilt angle of the substate support according to the present disclosure;

[0027] FIG. 3D is a graph illustrating an example of line width roughness (LWR) reduction as a function of top surface thickness loss for different tilt angles according to the present disclosure;

[0028] FIG. 4 is a graph illustrating an example of line width roughness (LWR) improvement as a function of ion beam voltage according to the present disclosure;

[0029] FIG. 5A illustrates an example of an ion beam angle distribution at a first predetermined chamber pressure according to the present disclosure;

[0030] FIG. 5B is a graph illustrating an example of power spectral density of line width roughness as a function of frequency before and after ion beam etching at the first predetermined chamber pressure according to the present disclosure;

[0031] FIG. 6A illustrates an example of an ion beam angle distribution at a second predetermined chamber pressure according to the present disclosure;

[0032] FIG. 6B is a graph illustrating an example of power spectral density of line width roughness as a function of frequency before and after ion beam etching at the second predetermined chamber pressure according to the present disclosure;

[0033] FIG. 7A illustrates a resultant ion beam angle distribution after ion beam etching at first and second offset angles relative to an ion beam direction according to the present disclosure;

[0034] FIG. 7B is a graph illustrating an example of power spectral density of line width roughness as a function of frequency before and after ion beam etching at the first and second offset angles according to the present disclosure;

[0035] FIG. 8 is a flowchart of an example of a method for ion beam etching according to the present disclosure; and

[0036] FIG. 9 is a flowchart of an example of a method for ion beam etching at first and second offset angles according to the present disclosure.

[0037] In the drawings, reference numbers may be reused to identify similar and / or identical elements.DETAILED DESCRIPTION

[0038] During substrate processing, some substrates include line features that extend parallel to one another and include side walls and a top surface. The line features are typically formed using photolithography. After photolithography, the side walls of the trenches may have unacceptable sidewall roughness. For example, the side walls may have a sinusoidal-like pattern with peaks and troughs. Reducing the side wall roughness without damaging the line features or causing excessive loss on the top surface is difficult.

[0039] The present disclosure relates to ion beam etching of the side walls of the line features to reduce roughness. The substrate is arranged on a substrate support and tilted at a predetermined tilt angle (relative to a plane transverse to the ion beam direction). In some examples, the line features are aligned parallel to an ion beam direction. In some examples, the predetermined tilt angle is in a range from 40Qto 88Qrelative to the planetransverse to the ion beam direction. In other examples, the predetermined tilt angle is in a range from 70Qto 88Qrelative to the plane transverse to the ion beam direction.

[0040] The ion beam etches the substrate in one direction and then the substate is tilted in an opposite direction (or the substrate is rotated 180Q) and the line features are etched from the opposite direction. During etching, the ion beam removes portions of the peaks on the side walls. In addition, material is re-sputtered from the peaks into the adjacent troughs.

[0041] In some examples, the pressure in the processing chamber is increased relative to a typical processing pressure to increase scattering of the ion beam. In some examples, the substrate is tilted as described above and rotated to first and second offset angles (e.g., in a range from + / - 0.1 - to + / - 5Q) on opposite sides of a line parallel to the ion beam direction. In some examples, the first offset angle and the second offset angle are equal in magnitude and opposite in polarity.

[0042] In some examples, ion beam etching is performed at first and second ion beam voltages in each substrate etch position. As can be appreciated, the ion beam etching according to the present disclosure reduces roughness of side walls of the line features while reducing material loss on the top surface of the line features.

[0043] 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.

[0044] 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 coils 64 induce a magnetic field inside of the enclosure 61 that strikes and maintains the plasma. A grid assembly 66 includes one or more parallel grids 67 with a pattern of aligned through holes 69. The grid assembly 66 is arranged between the plasma source 60 and a processing chamber 70. In some examples, the grid assembly 66 includes threegrids 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.

[0045] In some examples, the grid assembly 66 includes a first grid 87-1 that is connected to a voltage source 81 . The grid assembly 66 includes a second grid 87-2 that is connected to a voltage source 82. The grid assembly 66 includes a third grid 87-3 that is grounded. In some examples, the voltage source 81 operates in a range from 30V to 2000V 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.

[0046] In some examples, a positioning device 78 is configured to tilt the substrate support 86 in the processing chamber 70 relative to a plane perpendicular to the ion beam direction. The positioning device 78 is also configured to rotate the substrate support 86 using one or more motors and / or position sensors. 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.

[0047] A gas delivery system 90 and the gas distribution device 62 deliver a plasma gas mixture 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.

[0048] 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 98 including ions. The ions of the ion beam 98 pass through the through holes 69 inside of the aperture in the grid assembly 66 and impact an exposed surface of the substrate 84.

[0049] In FIG. 1 A, the ion beam processing system 50 optionally includes a shutter actuator 76 that moves a shutter 74 between a first or closed position (to block the ionbeam) and a second or open position to allow an ion beam 98 to reach the substrate 84 as shown in FIG. 1 A. The substrate support 86 can be arranged transverse to the ion beam during ion beam processing as shown in FIG. 1 A or tilted at a predetermined tilt angle as shown in FIGS. 1 B and 1 C.

[0050] As shown in FIG. 1 B, the positioning device 78 may tilt the substrate support 86 to a first tilt angle relative to the transverse direction. As shown in FIG. 1 C, the positioning device 78 may tilt the substrate support 86 to a second tilt angle relative to the transverse direction. Alternately, the positioning device 78 may tilt the substrate support as shown in FIG. 1 B and then rotate the substrate support 86 approximately 180Qfor ion beam etching from the opposite direction.

[0051] Referring now to FIGS. 1 D to 1 F, a substrate 1 10 includes line features 1 14 (e.g., lines) extending parallel to one another across the substrate 1 10. In FIG. 1 D, the line features 1 14 are spaced from one another and include a top surface 1 16 and side walls 1 18. Ion beam etching is used to reduce roughness on the side walls 1 18 due to the lithography process without significant loss of material from the top surface 1 16 as shown in FIG. 1 E. In FIG. 1 F, power spectral density of line width roughness (LWR) is shown before and after ion beam etching. A reduced area under the respective curves indicates reduced frequency variation corresponding to roughness reduction. As can be seen, ion beam etching significantly reduces roughness along the side walls without significant loss on the top surfaces.

[0052] Referring now to FIGS. 2A to 2C, the line features extend in parallel across the substrate. In some examples, the positioning device 78 also rotates the substrate support at offset angles relative to a plane parallel to the ion beam direction. For example, the positioning device 78 may rotate the substrate support by offset angles equal to + / -DQrelative to the ion beam direction during ion beam etching. In some examples, the offset angle D is set to an angular value that allows the ion beam to reach a middle location on the sidewalls of the line feature. For example in FIG. 2B, the angle D is equal a tangent of (di / 2) / d2 to allow the ion beam to reach the middle of the side wall when rotated in one direction or the other, where d1 is the length of line feature and d2 is the space CD.

[0053] Referring now to FIGS. 3A to 3D, roughness reduction and top surface loss are shown as a function of the tilt angle. In FIG. 3A, the ion beam is shown relative to the top surface 1 16 and the side walls 1 18 at a predetermined tilt angle. More material is removed from the side walls 1 16 as compared to the top surface 1 18. In FIG. 3B, linewidth roughness improvement is shown as a function of tilt angle. As can be seen, higher tilt angles (in dotted lines) correspond to increased roughness reduction. In FIG. 3C, high tilt angles also correspond to lower loss of material (e.g., photoresist) from the top surface 1 16. In FIG. 3D, the higher tilt angle has both higher LWR improvement and reduced loss of material from the top surface.

[0054] Referring now to FIG. 4, LWR after ion beam etching is shown as a function of ion beam voltage (corresponding to a difference in applied voltage between the first grid 87-1 and the second grid 87-2 of the grid assembly 87). Roughness continues to improve up to 1800eV for a low dose substrate. In some examples, multiple irradiation steps are performed at two or more different beam voltages. For example, a first step may be performed at a first beam voltage (e.g., 1200ev or 1800 eV) and a second step may be performed at a second beam voltage (e.g., 1800eV or 1200 eV).

[0055] Referring now to FIGS. 5A to 7B, examples of ion beam etching are shown. In FIG. 5A, ion beam etching is performed at a first predetermined pressure such as 0.2mT. In FIG. 5B, power spectral density of line width roughness is shown before and after ion beam etching at the first predetermined pressure such as 0.2mT. The line features are aligned with the ion beam direction.

[0056] In FIG. 6A, ion beam etching is performed at a second predetermined pressure higher than the first predetermined pressure. In some examples, the second predetermined pressure is in a range from 0.3 mT to 0.5 mT (e.g., 0.4mT). In FIG. 6B, power spectral density of line width roughness is shown before and after ion beam etching at the second predetermined pressure. As can be seen, increased pressure causes beam scattering and a wider ion beam. As a result, the roughness of the side walls is improved relative to operation at the first predetermined pressure shown in FIG. 5A.

[0057] In FIG. 7A, ion beam etching is performed with the substrate support tilted and rotated to a first offset angle (e.g., +DQrelative to a line parallel to the ion beam direction) and ion beam etching is performed. After completing ion beam etching at the first offset angle, the substrate is rotated to a second angle (e.g., -DQrelative to a line parallel to the ion beam direction) and ion beam etching is performed. Then, the process is repeated in the opposite direction. The ion beam etching produces a resultant ion angle distribution. In FIG. 7B, power spectral density of line width roughness is shown before and after ionbeam etching at the first and second angles. Using this approach, the roughness of the side walls is improved relative to operation at the first predetermined pressure in FIG. 5A.

[0058] Referring now to FIG. 8, a method for ion beam etching a substrate including line features is shown. At 310, the substrate with the line features is arranged on substrate support in the processing chamber. The line features are aligned parallel to the ion beam direction. At 314, the pressure in the processing chamber is set to a predetermined pressure. In some examples, the predetermined pressure is 0.2 mT. In some examples, the predetermined pressure is 0.4 mT.

[0059] At 318, the substrate support is tilted at a first tilt angle to etch from one direction. At 322, ion beam etching is performed. At 326, the substrate support is rotated 180Qat the first tilt angle (or tilted at a second tilt angle) to etch a second half of the line feature. At 340, ion beam etching is performed.

[0060] Referring now to FIG. 9, a method for ion beam etching a substrate including line features is shown. At 410, the substrate with the line features is arranged on substrate support in processing chamber. At 414, the pressure in the processing chamber is set to a predetermined pressure. In some examples, the predetermined pressure is 0.2 mT. In some examples, the predetermined pressure is 0.4 mT.

[0061] At 418, the substrate support is tilted at a first tilt angle and rotated to a first offset angle to etch one side wall of the first half of the line feature. At 422, ion beam etching is performed. At 426, the substrate support is rotated to a second offset angle to etch the other side wall of the first half of the line feature. At 430, ion beam etching is performed. At 434, the process is repeated in the opposite direction (either by rotating the substrate support 180Qor tilting in the opposite direction).

[0062] 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 line features, any one or more of those line features described with respect to any embodiment of the disclosure can be implemented in and / or combined with linefeatures 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.

[0063] 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.”

[0064] 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.

[0065] 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 endpointmeasurements, 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 operational parameters 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.

[0066] 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.

[0067] 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 systems that may be associated or used in the fabrication and / or manufacturing of semiconductor wafers.

[0068] 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 processing chamber including a substrate support configured to support a substrate including line features including a top surface and side walls; a grid assembly arranged between the plasma source and the processing chamber including aligned through holes configured to pass ions generated by the plasma to form an ion beam having an ion beam direction; and a positioning device configured to rotationally tilt the substrate support at a first predetermined tilt angle relative to the ion beam direction, wherein the first predetermined tilt angle is in a range from 40Qto 88Q, and wherein the ion beam etches the side walls of the line features.

2. The ion beam processing system of claim 1 , wherein: the ion beam etches the side walls of the line features from a first direction, and the positioning device at least one of rotates and tilts the substrate support to allow ion beam etching of the side walls of the line features in a second direction opposite to the first direction.

3. The ion beam processing system of claim 1 , wherein the positioning device is configured to rotationally align the line features relative to the ion beam direction.

4. The ion beam processing system of claim 1 , wherein: the positioning device is configured to rotationally align the line features at a first offset angle relative to the ion beam direction for ion beam etching one side of the side walls of the line features, and the positioning device is configured to rotationally align the line features at a second offset angle relative to the ion beam direction for ion beam etching an opposite side of the side walls of the line features.

5. The ion beam processing system of claim 4, wherein the first offset angle and the second offset angle are in a range from 0.5Qto 5Qof the ion beam direction.

6. The ion beam processing system of claim 5, wherein the first offset angle and the second offset angle are equal in magnitude and opposite in polarity.

7. The ion beam processing system of claim 1 , further comprising first and second voltage sources configured to generate a predetermined beam voltage across at least two grids of the grid assembly.

8. The ion beam processing system of claim 7, wherein: the first and second voltage sources are configured to generate a first predetermined beam voltage during a first period of ion beam etching of the substrate and a second predetermined beam voltage during a second period of ion beam etching of the substrate, and the first predetermined beam voltage is different than the second predetermined beam voltage.

9. The ion beam processing system of claim 1 , wherein a pressure in the processing chamber is in a range from 0.3mT to 0.5mT during ion beam etching.

10. The ion beam processing system of claim 1 , wherein the first predetermined tilt angle is in a range from 70Qto 88Q.1 1. A method for ion beam etching line features of a substrate, comprising: arranging a substrate including line features including a top surface and side walls on a substrate support in a processing chamber; tilting the substrate support at a first predetermined tilt angle; generating an ion beam at the substrate support, wherein the substrate support is tilted at the first predetermined tilt angle relative to an ion beam direction and the first predetermined tilt angle is in a range from 40Qto 88Q; and etching the side walls of the line features using the ion beam.

12. The method of claim 1 1 , wherein etching the side walls of the line features using the ion beam includes: etching the side walls of the line features from a first direction with the substrate support tilted at the first predetermined tilt angle, at least one of rotating and tilting the substrate support to allow ion beam etching of the side walls of the line features from a second direction with the substrate support tilted at the first predetermined tilt angle, wherein the second direction is opposite to the first direction.

13. The method of claim 11 , further comprising rotationally aligning the line features relative to the ion beam direction.

14. The method of claim 11 , further comprising: aligning the line features at a first offset angle relative to the ion beam direction for ion beam etching one side of the side walls of the line features, and aligning the line features at a second offset angle relative to the ion beam direction for ion beam etching an opposite side of the side walls of the line features.

15. The method of claim 14, wherein the first offset angle and the second offset angle are in a range from 0.5Qto 5Qof the ion beam direction.

16. The method of claim 15, wherein the first offset angle and the second offset angle are equal in magnitude and opposite in polarity.

17. The method of claim 11 , further comprising: generating a first predetermined beam voltage during a first period of ion beam etching of the substrate; and generating a second predetermined beam voltage during a second period of ion beam etching of the substrate, wherein the first predetermined beam voltage is different than the second predetermined beam voltage.

18. The method of claim 1 1 , wherein a pressure in the processing chamber is in a range from 0.3mT to 0.5mT during ion beam etching.

19. The method of claim 11 , wherein the first predetermined tilt angle is in a range from 70Qto 88Q.

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