Plasma chamber with multiphase rotating gas crossflow and peripheral conductance control ring

Abstract

The plasma processing chamber includes one or more sidewalls. A support surface in the one or more sidewalls holds a workpiece. A first gas injector along the one or more sidewalls injects a first gas flow in a first direction generally parallel to and across a surface of the workpiece. A first pump port along the one or more sidewalls generally opposite the first gas injector pumps out the first gas flow. A second gas injector along the one or more sidewalls injects a second gas flow in a second direction generally parallel to and across a surface of the workpiece. A second pump port along the one or more sidewalls generally opposite the second gas injector pumps out the second gas flow. A conductance control ring adjusts the conductance of the pump port and is positioned above the pump port and proximate to the plasma screen.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Patent Application No. 17 / 532,915, filed November 22, 2021, the entire contents of which are incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate to the field of semiconductor processing, and more particularly to a plasma chamber with a multiphase rotating gas crossflow and a peripheral conductance control ring. [Background technology]

[0003] During plasma etching, deposition, or other processing processes, a workpiece such as a semiconductor wafer is inserted into a sealed plasma reactor chamber, and gases are injected into the chamber over the wafer and then pumped out of the chamber. Plasma chambers often include (1) a parallel-plate capacitively coupled plasma (CCP) source (one electrode has the workpiece on its plasma-facing surface, and the other electrode has an array of gas inlet holes (showerhead) on its plasma-facing surface), or (2) an inductively coupled plasma (ICP) or microwave source (with a radio frequency (RF) window generally opposite the workpiece and facing the workpiece, and an array of gas inlet holes in or near the window).

[0004] In the axisymmetric gas flow approach described above, pressure and concentration gradients result in processing differences from the center to the edge of the workpiece. Furthermore, extraneous plasmas can form at the gas inlet holes due to proximity to high-density plasmas and disruption by high electric fields, resulting in non-uniformities that can change over time. More specifically, gas inlet holes are typically formed in a plate of material such as silicon or silicon carbide. High-energy ion impact on the hole edges can deform or facet the holes over time. The deformed holes can then generate high-intensity plasmas that disrupt the plate, necessitating showerhead replacement after a certain period of time (e.g., 600 hours). In some applications, approximately $15 of the cost of a semiconductor wafer can be attributed to the showerhead cost alone. Summary of the Invention

[0005] Embodiments disclosed herein include a plasma processing chamber including one or more sidewalls. A support surface within the one or more sidewalls holds a workpiece. A first gas injector along the one or more sidewalls injects a first gas flow in a first direction generally parallel to and across a surface of the workpiece, and a first pump port along the one or more sidewalls generally opposite the first gas injector pumps out the first gas flow. A second gas injector along the one or more sidewalls injects a second gas flow in a second direction generally parallel to and across the surface of the workpiece, and a second pump port along the one or more sidewalls generally opposite the second gas injector pumps out the second gas flow. One or more conductance control rings adjust the conductance of the first pump port and the second pump port and are positioned adjacent to the first plasma screen and the second plasma screen above the first pump port and the second pump port, respectively.

[0006] Embodiments disclosed herein include a method for performing a rotational gas cross flow in a plasma processing chamber and a non-transitory computer-readable medium having stored thereon software instructions that, when executed by a processor, cause the processor to rotate the gas cross flow in the plasma processing chamber by performing the following steps: during a first phase, the steps include injecting a first gas flow with a first gas injector in a first direction generally parallel to and across a surface of the device, and pumping the first gas flow out of the plasma processing chamber with a first pump port, the first gas injector being along one or more sidewalls of the plasma processing chamber at a first location and the first pump port being along the one or more sidewalls at a second location generally opposite the first gas injector. During a second phase, the step includes injecting a second gas flow in a second direction generally parallel to and across the surface of the device with a second gas injector and pumping the second gas flow out of the plasma processing chamber with a second pump port, the second gas injector being along the one or more sidewalls at a third location and the second pump port being along the one or more sidewalls at a fourth location generally opposite the second gas injector. One or more conductance control rings adjust the conductance of the first and second pump ports and are positioned above the first and second pump ports proximate to the first and second plasma screens, respectively.

[0007] Embodiments disclosed herein include a plasma processing chamber including one or more sidewalls. Supports for holding a workpiece are located within the one or more sidewalls. A first gas injector is located along the one or more sidewalls at a first location. A first pump port is located along the one or more sidewalls at a second location generally opposite the first gas injector. A second gas injector is located along the one or more sidewalls at a third location, and a second pump port is located along the one or more sidewalls at a fourth location generally opposite the second gas injector. The multi-phase rotating crossflow process includes at least a first phase and a second phase. The first phase includes injecting a first gas flow by the first gas injector in a first direction generally parallel to and transverse to a surface of the workpiece, and pumping the first gas flow by the first pump port. The second phase includes injecting a second gas flow in a second direction generally parallel to and transverse to the surface of the workpiece with a second gas injector and pumping the second gas flow with a second pump port. One or more conductance control rings adjust the conductance of the first and second pump ports and are positioned above the first and second pump ports and proximate the first and second plasma screens, respectively. [Brief explanation of the drawings]

[0008] [Figure 1A] FIG. 1 illustrates a top view of a plasma processing chamber having a multiphase rotating crossflow process according to one embodiment. [Figure 1B] 1A-1D show cross-sectional views of a plasma processing chamber in different embodiments. [Figure 1C] 1A-1D show cross-sectional views of a plasma processing chamber in different embodiments. [Figure 2A] FIG. 1 is a schematic diagram of a perspective semi-transparent view of a three-phase rotating cross-flow plasma processing chamber according to an embodiment. [Figure 2B]FIG. 1 is a schematic diagram of a top view of a three-phase rotating crossflow plasma processing chamber according to another embodiment. [Figure 2C] 1 shows a timing diagram of a three-phase rotational crossflow process performed by a plasma processing chamber. [Figure 2D] 1 illustrates a perspective view of the top of a chamber lid showing a gas supply system above, according to an embodiment. [Figure 2E] 1 shows a perspective cross-sectional view of a plasma chamber according to an embodiment. [Figure 2F] 1 shows a cross-sectional view of a plasma chamber. [Figure 2G] 1 illustrates a perspective view of a vacuum chamber having pumping ports formed therein, according to an embodiment. [Figure 2H] 1 illustrates a perspective view of a vacuum chamber having pumping ports formed therein, according to an embodiment. [Figure 2I] 1 shows a cross-sectional view of a plasma processing chamber with a respective conductance control ring for each pump port. [Figure 2J] 1 shows a cross-sectional view of a plasma processing chamber with a respective conductance control ring for each pump port. [Figure 2K] An embodiment is shown in which multiple pump ports 120 are provided with a single conductance control ring 285 . [Figure 2L] An embodiment is shown in which multiple pump ports 120 are provided with a single conductance control ring 285 . [Figure 2M] 1 shows a cross-sectional view of a plasma processing chamber in an embodiment in which a conductance control ring is positioned directly below and abutting the plasma screen. [Figure 2N] FIG. 1 illustrates a perspective semi-transparent view of an exemplary inductively coupled plasma (ICP) chamber with a three-phase rotating crossflow according to one embodiment. [Figure 2O] FIG. 1 illustrates a perspective semi-transparent view of an exemplary inductively coupled plasma (ICP) chamber with a three-phase rotating crossflow according to one embodiment. [Figure 2P]FIG. 1 illustrates a perspective semi-transparent view of an exemplary inductively coupled plasma (ICP) chamber with a three-phase rotating crossflow according to one embodiment. [Figure 3A] FIG. 2 illustrates a top view of a plasma processing chamber having a four-phase rotating crossflow, according to an embodiment. [Figure 3B] FIG. 1 illustrates a four-phase rotating crossflow process according to an embodiment. [Figure 3C] FIG. 10 illustrates a four-phase rotating crossflow process with intentional non-uniform center and edge gas injection with opposing side port pumping according to further aspects of the disclosed embodiment. [Figure 3D] FIG. 10 illustrates a four-phase rotating crossflow process with intentional non-uniform center and edge gas injection with opposing side port pumping according to further aspects of the disclosed embodiment. [Figure 3E] FIG. 1 illustrates a single phase of a multiphase rotary crossflow process in which at least a portion of the gas flow is diverted to the side of the workpiece rather than 100% crossflow across the workpiece, according to an embodiment. [Figure 3F] FIG. 10 illustrates one phase of a multiphase cycle in which gas flow is directed across the workpiece using a smaller width pump port, according to an embodiment. [Figure 4A] FIG. 10 illustrates a top view of the rotating gas flow in a three-phase rotating crossflow plotted every 60° in time, according to an embodiment. [Figure 4B] FIG. 10 illustrates a top view of the rotating gas flow in a three-phase rotating crossflow plotted every 60° in time, according to an embodiment. [Figure 4C] FIG. 10 illustrates a top view of the rotating gas flow in a three-phase rotating crossflow plotted every 60° in time, according to an embodiment. [Figure 5] 1 illustrates a cross-sectional view of a portion of a wafer including stacked memory devices that may be processed by a plasma processing chamber including a rotating gas crossflow, according to an embodiment. [Figure 6]Referring now to FIG. 6, a block diagram of a processing tool utilizing machine learning (ML) models is shown, according to an embodiment. [Figure 7A] FIG. 1 is a flow diagram illustrating a process for generating an ML model, according to an embodiment. [Figure 7B] FIG. 1 is a flow diagram illustrating a process for generating an ML model, according to an embodiment. [Figure 8] FIG. 1 is a flow diagram illustrating a process for developing a process recipe using the illustrated ML model, according to an embodiment. [Figure 9] FIG. 1 shows a flow diagram illustrating a process for baselining a processing tool, according to an embodiment. [Figure 10] 1 is a diagrammatic representation of a machine in the exemplary form of a computer system within which a set of instructions for causing the machine to perform any one or more of the methods described herein may be executed, according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] The disclosed embodiments relate to a plasma chamber with a multiphase rotating gas crossflow and a peripheral conductance control ring. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent to those skilled in the art that the disclosed embodiments may be practiced without these specific details. In other instances, well-known aspects, such as integrated circuit fabrication, are not described in detail so as not to unnecessarily obscure the disclosed embodiments. Furthermore, it should be understood that the various embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale.

[0010] Conventional plasma chambers (i.e., CCPs or ICPs) typically inject gases axisymmetrically onto the workpiece through gas inlet holes typically located directly above the workpiece or symmetrically around the periphery of the workpiece. As noted above, the axisymmetric gas flow creates pressure and concentration gradients that can damage the gas hole entrances and cause non-uniformities on the workpiece. That is, wear occurs at the gas holes in the high-density, high-|E| plasma region, changing the hole geometry and potentially modifying the local plasma characteristics near the hole as the plasma penetrates. Furthermore, the change in geometry can result in changes in local gas flow rates and velocities. This, in turn, requires relatively frequent showerhead replacement, increasing the cost of the workpiece.

[0011] Accordingly, embodiments disclosed herein are directed to a plasma chamber (e.g., CCP or ICP) with multi-phase rotationally regulated gas cross-flow for etching, deposition, or other material processing. The plasma processing chamber includes two or more gas injectors and two or more pump ports along a sidewall. In a first phase, one of the gas injectors directs gas flow in one direction generally parallel to and across the surface of the workpiece or device, where the gas is then pumped through the pump port. In a second phase, another gas injector is used to rotate the gas flow, directing the gas flow in another direction generally parallel to and across the surface of the workpiece, where the gas is then pumped through another pump port. In another embodiment, a gas inlet valve connected to the gas injector and / or a throttle valve connected to the pump port can be used to regulate the rotational gas flow.

[0012] A plasma processing chamber with rotationally regulated gas crossflow eliminates the need for a showerhead (and gas inlet holes) in the high-density, high |E| plasma region, thereby preventing sources of plasma non-uniformity. The disclosed embodiments prevent the plasma from being generated in the gas holes due to proximity to the high-density plasma or being destroyed due to high electric fields, thereby preventing non-uniformity and changes in plasma characteristics over time. The disclosed embodiments avoid high center-to-edge pressure and concentration gradients that cause center-to-edge processing differences. The pressure distribution can be tailored across the plasma volume to minimize plasma non-uniformity. Furthermore, the disclosed embodiments eliminate stagnant, low-gas velocity regions (i.e., the center of the workpiece) for uniform removal of reactants and by-products.

[0013] 1A-1C illustrate embodiments of a plasma processing chamber of a plasma reactor having a multiphase rotating crossflow process. FIG. 1A illustrates a top view of a plasma processing chamber having a multiphase rotating crossflow process according to one embodiment. FIG. 1B and FIG. 1C illustrate cross-sectional views of different embodiments of the plasma processing chamber.

[0014] 1A and 1B, plasma processing chamber 100A includes one or more chamber sidewalls 112 having a support surface 114 therein for holding a workpiece 116 (e.g., a semiconductor wafer) for processing. Plasma processing chamber 100 can be used to perform various processes on workpiece 116, such as etching, deposition, surface treatment, material modification, etc., by distributing gases within the chamber. For example, plasma processing chamber 100A can include, but is not limited to, a plasma etch chamber, a plasma-enhanced chemical vapor deposition chamber, a physical vapor deposition chamber, an ion implantation chamber, an atomic layer deposition (ALD) chamber, an atomic layer etching (ALE) chamber, or other suitable vacuum processing chambers for fabricating various devices.

[0015] In one illustrated embodiment, one or more sidewalls 112 surround a processing region 110 in which a workpiece 116 (e.g., a wafer or substrate) is processed. In the illustrated example, the plasma processing chamber 100A is shown with an axisymmetric shape (e.g., cylindrical) resulting in a single cylindrical sidewall 112. However, in other embodiments, the plasma processing chamber 100A may have any other shape, such as an ellipse, which would also result in a single sidewall 112, or may have a shape such as a square or rectangle, in which case the plasma processing chamber 100A would have four sidewalls.

[0016] According to a disclosed embodiment, the plasma processing chamber 100 includes at least two gas injectors 118A and 118B (collectively referred to as gas injectors 118) and at least two pump ports 120A and 120B (collectively referred to as pump ports 120) located generally along one or more sidewalls 112. In one embodiment, the gas injectors are formed in openings that penetrate a liner of the sidewall 112. The plasma processing chamber 100A can be configured to use the gas injectors 118 and pump ports 120 to rotate a gas flow 124 laterally across the workpiece 116 to provide a multiphase rotational crossflow process. In one embodiment, the multiphase rotational crossflow process includes at least a two-phase cycle, and may also include a three-phase cycle, a four-phase cycle, etc., in which each phase of gas is injected from one side of the plasma processing chamber 100A and pumped out generally from the opposite side. As used herein, the term "located generally along one or more sidewall(s)" is intended to describe that either the gas injectors 118 and / or pump ports 120 may be located in a sidewall, horizontally abutting or adjacent to a sidewall, or may be located in a peripheral region of the chamber lid or a peripheral region of the chamber bottom.

[0017] The lateral rotation of the gas flow across the workpiece 116 improves control of gas velocity and pressure gradients, resulting in better process uniformity across the wafer and from wafer to wafer.

[0018] 1B, the plasma processing chamber 100A further includes a chamber lid 104 covering the sidewall 112. The support pedestal 108 may include a support surface 114 on which the workpiece 116 rests. In an embodiment, the support pedestal 108 and support surface 114 are fixed and non-rotatable, and the workpiece 116 attached thereto does not rotate during processing. In an embodiment, the workpiece 116 is electrostatically attached to the support surface 114. In another embodiment, the support surface 114 is axially movable for plasma gap adjustment or wafer transfer. A processing region 110 within the plasma processing chamber 100A is defined by the area between the chamber lid 104, the support pedestal 108 (and support surface 114), and the sidewall 112. Below the sidewall 112 is a chamber floor 106, which is below the processing region 110. The support pedestal 108 is below the chamber lid 104 and above the chamber floor 106 and is surrounded by sidewalls 112. In an embodiment, the chamber lid 104 and the support surface 114 can be separated by a distance of approximately 25 mm to 200 mm. In an embodiment, the plasma processing chamber 100A is a parallel-plate capacitively coupled plasma (CCP) process chamber with an upper electrode 105 above the workpiece 116. A bottom electrode is included at location 113 within the support pedestal 108 below the support surface 114. In one embodiment, the upper electrode 105 is connected to an RF source having a frequency in the range of 40 to 200 MHz, with a power in the range of 200 to 10,000 watts. In one embodiment, the bottom electrode is connected to ground. A plasma is generated above the wafer and between the two electrodes. In one embodiment, the workpiece 116 is electrostatically clamped to the support surface 114 by one or more clamping electrodes located within or below the support surface 114. In an embodiment, the workpiece 116 is connected to a bias electrode (e.g., at a low RF frequency in the range of 0.1-20 MHz) for additional plasma control during processing. The generated plasma can be pulsed during processing by pulsing the power to the first electrode 105.

[0019] In embodiments, the workpiece 116 may include any substrate commonly used in a semiconductor manufacturing environment. For example, the workpiece may include a semiconductor wafer. In embodiments, the semiconductor material may include, but is not limited to, silicon or III-V semiconductor materials. The semiconductor wafer may, in some embodiments, be a semiconductor-on-insulator (SOI) substrate. Typically, semiconductor wafers have standard dimensions (e.g., 200 mm, 300 mm, 450 mm, etc.). However, it should be understood that the workpiece 116 may have any dimensions. Embodiments may also include workpieces comprising non-semiconductor materials, such as glass or ceramic materials. In embodiments, the workpiece 116 may include circuits or other structures fabricated using semiconductor processing equipment. In yet another embodiment, the workpiece 116 may include a reticle or other lithography mask object.

[0020] 1A and 1B illustrate an example of a two-phase cyclic rotating crossflow process. In a first phase, a gas injector 118A injects a first gas flow 124A in a first direction generally parallel to and across the surface of the workpiece 116 and has an opposite pump port 120A along one or more side walls 112 generally opposite the gas injector 118A for pumping out the gas flow 124A. In a second phase, a gas injector 118B injects a second gas flow 124B in a second direction generally parallel to and across the surface of the workpiece 116 and has an opposite pump port 120B along one or more side walls 112 generally opposite the gas injector 118B for pumping out the gas flow 124B. In an embodiment, the direction of the second gas flow 124B is different from the direction of the first gas flow 124A. In one embodiment, generally parallel means within about 0° to 15°, and generally opposite means within about 0° to 30°.

[0021] Thus, gas injector 118A and opposite pump port 120A form one gas injector-pump port pair, while gas injector 118B and opposite pump port 120B form a second gas injector-pump port pair. In one embodiment, gas injectors 118A and 118B can each include an array of individual gas injectors, as shown in FIG. 1A. In alternative embodiments, gas injectors 118A and 118B each include only a single vent gas injector. In some embodiments, gas injector 118A includes an array of individual gas injectors and gas injector 118B is a single vent gas injector, or vice versa.

[0022] As shown in FIG. 1A, along a horizontal plane generally parallel to the orientation of the workpiece 116, each gas injector-pump port pair (i.e., a gas injector and an opposing pump port) is symmetrically positioned along the sidewall 112 of the plasma processing chamber 100A. Any number of gas injectors 118 and pump ports 120 may be provided. Generally, one gas injector-pump port pair may be offset from the position of an adjacent injector-pump port pair by an angle equal to a total of 360 degrees divided by the number of injector-pump port pairs to ensure equal gas distribution. For example, if there are two injector-pump port pairs, the injector-pump port pairs are offset from each other by 180 degrees (360 degrees / 2). If there are three injector-pump port pairs, the injector-pump port pairs are offset by 120 degrees (FIGS. 2A and 2B). In some embodiments, as shown, the span of a gas injector is less than the span of the corresponding pump port. In other embodiments, the span of a gas injector is the same as the span of the corresponding pump port. In other embodiments, the span of a gas injector is greater than the span of the corresponding pump port. Gas can be injected through gas injector openings of various geometries, such as holes, slots, etc., and different gas injectors can have the same or different geometries and sizes.

[0023] In some embodiments, the number of gas injectors 118 and pump ports 120 is equal, while in other embodiments, the number of gas injectors 118 and pump ports 120 may be different. In some embodiments, a single pump port is associated with a corresponding gas injector, as depicted. In other embodiments, an array of pump ports is associated with a corresponding gas injector.

[0024] 1B, the gas injector 118 is located within an opening in the sidewall 112 within the processing region 110. For example, the opening may be located in a liner of the sidewall 112. In an embodiment, the opening in the sidewall 112 is located vertically between the chamber lid 104 and the substrate support pedestal 108. In the illustrated embodiment, the opening in the sidewall 112 is adjacent to the bottom of the chamber lid 104.

[0025] Along a vertical plane generally parallel to the orientation of the support pedestal 108, the location of the pump port 120 may be vertically offset from the location of the gas injector 118 by a distance approximately equal to the distance between the bottom of the chamber lid 104 and the top of the support pedestal 108 in one embodiment. In this embodiment, the pump port 120 may be located in a cavity between the sidewall 112 and the support pedestal 108 and above the chamber floor 106. In another embodiment, the pump port 120 may be located in an additional opening in the sidewall 112 anywhere between the chamber lid 104 and the chamber floor 106. In another embodiment, gas may be injected from an outer perimeter region of the chamber lid and / or pumped from an outer perimeter region of the chamber bottom and flow over the workpiece processing region, still substantially parallel to the workpiece.

[0026] As mentioned above, the plasma processing chamber 100A of the disclosed embodiments injects gases generally parallel to and across the workpiece 116. This contrasts with the typical axisymmetric top-down gas flow injection from a "showerhead" electrode in a CCP source reactor, and with the radial outward / downward gas injection from a nozzle array near a central axis in an ICP or microwave source reactor. Additionally, in embodiments, instead of pumping ports or pumping plenums located axisymmetrically around the periphery of the workpiece, gases are preferentially pumped out from the side of the workpiece generally opposite the injection side.

[0027] In an embodiment, the gas flow 124 in each cross-flow phase can be switched on and off to control the rotation of the gas flow. In another embodiment, instead of switching the gas flow 124 on and off, a modulating function may be applied to the flow rate of the gas flow 124 from the gas injector 118 and / or the outlet conductance (or pressure) produced by the pump port 120, approximating an open / closed state or ramping between states using a modulating function such as a sine wave. As shown in FIG. 1B , the flow rate of one or both of the first gas flow 124A and the second gas flow 124B can be adjusted using one or more gas inlet valves 122A and 122B (e.g., piezoelectric valves) connected to the gas injectors 118A and 118B, respectively. In an embodiment, the gas inlet valves 122A and 122B are connected to one or more gas sources 126 so that a single gas or a mixture of different gases can be injected into the processing region 110 during each rotation phase. In one embodiment, a constant total gas flow is applied by the gas injector 118, which can smoothly and sequentially inject gas flow across different sides of the workpiece 116 in a complete cycle, which can then be repeated as needed.

[0028] 1B also shows plasma screens 129A and 129B positioned above pump ports 120A and 120B, respectively. Plasma screens 129A and 129B are grounded or floating screens positioned above the respective pump ports and can help reduce penetration of the plasma further down at the bottom of the chamber. Plasma screens 129A and 129B have a shape (e.g., a ring shape or a curved rectangular shape) that generally matches the shape of pump ports 120A and 120B and covers pump ports 120A and 120B.

[0029] Additionally, in some embodiments, one or more of the pump ports 120 can be adjusted. For example, pump port conductance (pressure) can be adjusted using pressure control valves on pump ports 120A and 120B or peripheral conductance control rings 127A and 127B (described further below). Also shown are pump ports 120A and 120B connected to one or more pumps 132 to exhaust gas. For example, conductance control ring 127A of pump port 120A can be in an open position, while conductance control ring 127B can be in a closed position to exhaust first gas flow 124A. Conductance control rings 127A and 127B can be smoothly operated between two states of conductance or pressure, which are then cycled in a similar order as gas injectors 118A and 118B. In the illustrated embodiment, conductance control rings 127A and 127B can be pressure control valves, such as throttle valves.

[0030] In some embodiments, the plasma processing chamber 100A may further include sensors 131 and systems for sensitively and real-timely monitoring process chamber conditions, including gas flow, velocity, pressure, temperature, etc. Particular embodiments may include capacitive wall sensors, on-chip or off-chip thermal sensors, pressure sensors, and / or integrated sensors (capacitive and thermal sensors) on a substrate, such as a ceramic substrate, or a glass substrate, silicon substrate, or flexible substrate. In some embodiments, sensors are distributed throughout the chamber to monitor chamber conditions at various locations and correlate them to overall process performance, such as etch rate, etch non-uniformity, particle generation, process drift, and pressure uniformity. In one embodiment, multiple pressure sensors or an array of pressure sensors may be distributed throughout the chamber to provide data regarding gas flow (e.g., rotation speed, uniformity, velocity) during processing.

[0031] 1B further shows that plasma processing chamber 100A is connected to a controller 140, which may be connected to a user interface 142. In some embodiments, the controller may be connected to gas inlet valve 122, conductance control ring 127, gas source 126, pump 132, and sensor 131 to control the operation of plasma processing chamber 100A. A user may set process parameters and monitor operation of plasma processing chamber 100A through controller 140 from user interface 142.

[0032] The multi-phase architecture of a plasma processing chamber allows for many different configuration options. For example, FIG. 1C shows a cross-sectional view of a plasma processing chamber 100B in an embodiment that includes a top-down gas flow in addition to one or more pairs of gas injectors 118 and pump ports 120 that provide side-to-side gas flow. In this embodiment, the chamber lid 104 can be configured with a showerhead plate 128 (the controller and UI in FIG. 1B are not shown for simplicity). The showerhead plate 128 can have a central manifold 125 and one or more outer manifolds 130 for distributing gases into the processing region 110 along with the gases distributed by the gas injectors 118A and 118B. Although the use of showerhead plate 128 may introduce additional gas into the chamber with a vertical velocity component, the injection of gas from one side by gas injector 118A and pumping to the other side of workpiece 116 by pump port 120A generally results in a horizontal component of gas velocity across most of workpiece 116. Similarly, pump port 120 may be on the sidewall 112 or on the top or bottom surface of the chamber, but is generally located opposite the injection side. Thus, although there may be a vertical velocity component of the exhaust gas, the gas velocity is generally horizontal, parallel to the workpiece 116 in the region above workpiece 116.

[0033] 2A-2C illustrate a plasma processing chamber of a plasma reactor having a three-phase rotating crossflow process according to one embodiment. Fig. 2A is a schematic diagram of a perspective semi-transparent view of a three-phase rotating crossflow plasma processing chamber. Fig. 2B is a schematic diagram of a top view of a three-phase rotating crossflow plasma processing chamber according to another embodiment.

[0034] 2A, a plasma processing chamber 200A having a three-phase rotating crossflow process is similar to the embodiment shown with respect to FIGS. 1A-1C in that the chamber 200 includes a sidewall 212 surrounding a workpiece 216. However, in addition to two gas injectors 218A and 218B and two opposing pump ports 220A and 220B, the plasma processing chamber 200 further includes a gas injector 218C and an opposing pump port 220C located on generally opposite sides of the sidewall 212 for pumping gas flow. Gas injector 218A and opposing pump port 220A form one gas injector-pump port pair. Gas injector 218B and opposing pump port 220B form a second gas injector-pump port pair. And, gas injector 218C and opposing pump port 220C form a third gas injector-pump port pair. (Gas injectors 218A-218C are collectively referred to as gas injectors 218, and pump ports 220A-220C are collectively referred to as pump ports 220).

[0035] In this embodiment, the gas injectors 218 are each configured as a single vent in the sidewall 212, as shown. In one embodiment, the gas injectors 218 are positioned symmetrically about the central axis of the plasma processing chamber 200, and the pump ports 220 are positioned symmetrically about the central axis of the plasma processing chamber 200, as shown. In a three-phase rotating crossflow embodiment including three injector-pump port pairs, the injector-pump port pairs are offset from each other by 120° (360° / 3). More specifically, the gas injectors 218 are positioned approximately 120° from each other, and the pump ports 220 are positioned 120° from each other. The pump ports 220 are positioned laterally between and vertically offset from the spaced-apart gas injectors 218.

[0036] FIG. 2B shows a top view of plasma processing chamber 200B including an array of individual gas injectors, referred to as gas injector array 218D, distributed around the periphery of sidewall 212. Also shown are three gas inlet valves 122A-122C and three conductance control rings 127A-127C, one for each pumping port 120 (see FIG. 1B). A set of miniature gas injectors (such as four injectors as shown) in gas injector array 218 can be regulated by one of the gas inlet valves 122A-122C to create a gas flow in various directions across workpiece 216. The gas flow is then pumped out by one of the pumping ports controlled by a corresponding one of conductance control rings 127A-127C generally opposite the regulated gas inlet valves 122A-122C. In this case, in an embodiment, the span of the gas injector is greater than the span of the corresponding pump port, resulting in a somewhat convergent flow (eg, flow 299) at the relatively narrow pump port.

[0037] 2C shows in more detail a timing diagram for a three-phase rotary crossflow process performed by plasma processing chamber 200B. The timing diagram assumes the presence of three gas inlet valves 122 (GV1, GV2, GV3) and three conductance control rings 127 (PV1, PV2, PV3). The X-axis represents time, and the Y-axis represents i) the percentage of gas valves open in the bottom row, the percentage of pump ports closed in the middle row, and the chamber pressure measured by a Baratron (manometer) in the top row.

[0038] A controller may be connected to plasma processing chamber 200 and configured to control gas inlet valves 122A-122C and conductance control rings 127A-127C. The controller initiates a first phase by substantially opening GV1 in a range of 20-100% and partially opening GV2 and GV3, for example, in a range of approximately 0-5%. In the first phase, PV1 is open while PV2 and PV3 are closed, and the chamber pressure is between 1 mT and 500 mT.

[0039] Near the transition between the first and second phases, GV1 begins to close, and GV2 is fully opened 20-100%, rotating the gas flow direction and initiating the second phase. GV1 and GV3 are partially open, approximately 0-5%. During the second phase, the controller opens PV2 and keeps PV1 and PV3 closed. Chamber pressure can be maintained between 1 mT and 500 mT in some embodiments, and between 10 mT and 200 mT in other embodiments.

[0040] Near the transition between the second and third phases, GV2 is ramped down, and the gas flow direction is rotated by opening GV3 20-100% to begin the third phase. GV1 and GV2 are partially open, approximately 0-5%. During the third phase, the controller opens PV3 and keeps PV1 and PV2 closed. This completes a three-phase cycle, which can be repeated as needed. As shown, a relatively constant chamber pressure is maintained throughout the three gas flow phases. In one embodiment, sequentially opening and closing GV1, GV2, and GV3 effectively creates a rotating gas flow that can mimic wafer rotation. In one embodiment, a single full rotation of the gas flow is performed at a rate ranging from approximately 100 milliseconds to 10 seconds.

[0041] Various changes can occur between gas flow phases and cycles. That is, each parameter controlling the operation of the plasma processing chamber can vary across phases and cycles. For example, the time to complete an entire cycle can be the same or different across different cycles. The time to complete a phase can be the same or different within a cycle and across different cycles. The direction of gas flow (e.g., clockwise or counterclockwise) can be the same or different within a phase of a cycle, can be discontinuous, and can be the same or different across a cycle. The gas flow rate can be the same or different within a phase of a cycle and can be the same or different across a cycle. The percentage of gas valve opening and the time the gas valve is open can be the same or different within a phase of a cycle, or across the entire cycle. The percentage of conductance control ring opening and the time the conductance control ring is open can be the same or different within a phase of a cycle and across the entire cycle. For example, in embodiments, rotation is performed at one speed for a first portion of the process and then decelerated to a second speed for a second portion of the process. In embodiments, rotation is performed at one speed for the first portion of the process and then accelerated to a second speed for the second portion of the process. In embodiments, rotation is faster for a first portion of a single rotation cycle and slower for a second portion of the rotation. In embodiments, rotation is slower for a first portion of a single rotation cycle and accelerated for a second portion of the rotation. By varying the rotation speed within a single cycle or between cycles, process non-uniformities can be compensated for. In other embodiments, the direction is changed between clockwise and counterclockwise within a cycle, between cycles, or between sets of cycles. Similarly, in embodiments, the gas flow rates between the first, second, and third phases can be changed within a cycle, between cycles, or between sets of cycles.

[0042] FIG. 2D shows a perspective view of the top of the chamber lid 104, with the gas supply system shown above. In one embodiment, the gas supply system 225 includes an array of gas inlet valves 122, each of which is disposed symmetrically above and around the periphery of the chamber lid 104. In the illustrated embodiment, the gas supply system 225 includes six gas inlet valves 122, although the specific number can vary, such as two or more. The top side of each of the gas inlet valves 122 can be connected to a gas line assembly 250 arranged in a spoke and hub formation, where the hub is connected to the gas source 126 shown in FIGS. 1B and 1C. The bottom side of the gas inlet valves 122 can be connected to a respective set of recursive gas lines 252. Each set of recursive gas lines 252 can be connected to one or more gas injectors 118. In the particular embodiment shown, there are six sets of recursive gas lines 252 with four inlets connected to each gas injector 118 for a total of 24 inlets.

[0043] In embodiments, the gas inlet valve 122 may include an analog variable conductance, high-speed gas valve that allows for fast response without excessive pressure spikes that can lead to gas lighting or arcing or make the RF match control difficult to follow. Specific examples of gas inlet valves include commercially available Swagelok eDE valves and Fujikin Piezo valves. The Swagelok eDE valve may have an open / close time of 15-20 milliseconds, provide good atmospheric / vacuum sealing, and have a lifespan of 40 million cycles. The Fujikin Piezo valve has proportional flow, an open / close time of 10 milliseconds, and, depending on use, may have a lifespan well beyond 40 million cycles. Both may provide a gas flow of up to 2.5 slm at an upstream pressure of 400 T.

[0044] FIG. 2E shows a perspective cross-sectional view of the plasma chamber. This view illustrates the connection between the recursive gas line 252 and the gas injector 118. Also shown is that, in one embodiment, the sidewall 112 includes an outer sidewall 112A and an inner sidewall 112B (or liner), a gas injector is formed in the space between the outer sidewall 112A and the inner sidewall 112B, and gas is injected from the recursive gas line 252 through an opening in the inner sidewall 112B. FIG. 2F shows a cross-sectional view of the plasma chamber 200F, and FIGS. 2G and 2H show perspective views of the vacuum chamber 275. The plasma chamber 200F is similar to the embodiment shown in FIG. 1C, but also illustrates an embodiment of the vacuum chamber 275 in which the pump ports 120 (120A and 120B) can be formed. In this embodiment, the vacuum chamber 275 is controlled under dynamic vacuum by the pump 132. In one embodiment, the vacuum pressure can range from 1 mT to 500 mT. In one embodiment, the chamber floor 106 includes an upper chamber floor 106A and a lower chamber floor 106B. The pumping ports 120 are formed in a cavity within the vacuum chamber 275 between the upper chamber floor 106A and the lower chamber floor 106B. The pumping ports 120 are also symmetrically positioned about the support pedestal 108.

[0045] An actuator 277 is connected to the conductance control ring 127 and controls each pump port 120. The pump ports 120 are closed and opened by one of the actuators 277 raising and lowering the corresponding conductance control ring 127 within the cavity of each pump port 120. Figure 2G shows that in one embodiment, the conductance control ring 127 may include a single, integral body for sealing off the associated port, while Figure 2H shows that in another embodiment, the conductance control ring 127 may be divided into one or more adjacent sections (in this case, two), each controlled by a corresponding actuator 277.

[0046] 2F, right side 127A is lowered (open) to pump out gas injected by gas injector 118A, and left side 127B is raised (closed). During the transition from one cross-flow phase to another, conductance control ring 127A moves up to a closed position, while conductance control ring 127B moves down to an open position to pump out a volume of gas or air, including a significant amount of dead air due to the length of vacuum chamber 275, from both processing region 110 and pump port 120B.

[0047] Peripheral conductance control ring In accordance with another aspect of the disclosed embodiment, the plasma processing chamber is provided with one or more conductance control rings located above the pumping port, rather than at the bottom of the vacuum chamber 275, in close proximity to both the surface of the processing region 110 and the plasma screen. As a result, less gas or air needs to be evacuated from the processing region, improving plasma confinement and reducing gas residence time above the workpiece 116.

[0048] There are various embodiments in terms of location and configuration, for example, one or more conductance control rings can be positioned above or below the processing region adjacent to the plasma screen 129 at each of the pump ports 120.

[0049] 2I and 2J show cross-sectional views of plasma processing chambers 200I and 200J, each including a respective conductance control ring 281A and 281B for pump ports 120A and 120B. Here, the conductance control ring 281 is positioned immediately adjacent to the plasma screen 129 (in the closed position) for each pump port 120A and 120B and moves vertically. For example, if there are three pump ports 120, there may be three conductance control rings 281. In this embodiment, a solid conductance control ring 281 is provided for each pump port 120, and the conductance control rings 281 are independently moved up and down to abut against the corresponding plasma screens 129A and 129B.

[0050] 21 shows an embodiment in which conductance control rings 281A and 281B are positioned below plasma screens 129A and 129B in corresponding pump ports 120A and 120B. Actuators 287A and 287B are positioned below pump ports 120A and 120B and move conductance control ring 281 vertically up and down to open and close pump ports 120, respectively. Conductance control ring 281B is shown in the closed position, directly abutting plasma screen 129B.

[0051] 2J illustrates an embodiment in which conductance control rings 283A and 283B are positioned above plasma screens 129A and 129B in processing region 110. One or more actuators 279A and 279B are positioned above chamber lid 104 and move conductance control rings 283A and 283B vertically up and down to respectively open and close pump port 120. Conductance control ring 283B is shown in a closed position, directly abutting plasma screen 129B in processing region 110. In the embodiments of FIGS. 2F-2J, the conductance control rings may include a solid plate of a material such as, for example, quartz.

[0052] Actuator 279 is coupled to controller 140 (FIG. 1B), which synchronizes the movement of conductance control rings 283A and 283B to the various cross-flow phases. In embodiments, controller 140 may use machine learning to set and / or control the gas pulse and vertical movement sequence / timing.

[0053] Figures 2K and 2L show an embodiment in which a single conductance control ring 285 is provided for multiple pump ports 120. Figure 2K shows a perspective exploded view of the conductance control ring 285 and pump ports 120. Figure 2L shows a cross-sectional view of the conductance control ring 285 positioned above and over the pump ports 120 inside plasma processing chamber 200L.

[0054] 2K and 2L show an embodiment in which a conductance control ring 285 is positioned above and directly above the plasma screen 129 (129A, 129B, and 129C) in the corresponding pump port 120. The conductance control ring 285 is disc-shaped with one or more openings 287, such as one or more slots or multiple through-holes. The conductance control ring 285 has an outer diameter that approximately matches the outer diameter of the processing region 110 and an inner diameter that approximately matches the diameter of the pedestal 108. In the illustrated embodiment, the conductance control ring 285 has a single opening 287 sized to match the lateral size of a pump port 120 and can be rotated (indicated by the arrow) so that the opening 287 is aligned with the currently active pump port 120.

[0055] FIG. 2M shows a cross-sectional view of plasma processing chamber 200M in an embodiment in which conductance control ring 285 is positioned directly below and against plasma screen 129.

[0056] 2K-2M, whether the conductance control ring 285 is above or below the plasma screen 129, one or more actuators 291 are positioned within the sidewall of the chamber or one or more pump ports to rotate the conductance control ring 285 laterally or horizontally around the pedestal 108. The actuators 291 may be mechanical or magnetic. The actuators 291 are connected to a controller 140 (FIG. 1B), which synchronizes the rotational motion of the conductance control ring 285 with the various cross-flow phases. In embodiments, the controller 140 may use machine learning to set and / or control the gas pulse and rotation sequence / timing. The actuators 291 stop the rotation of the conductance control ring 285 so that the opening 287 is aligned with one of the pump ports 120, opening the corresponding pump port and closing the other pump port. In Figures 2L and 2M, opening 287 in conductance control ring 285 is aligned over pump port 120A and blocks pump port 120B (and pump port 120C, not visible in this view). Figures 2N-2P illustrate perspective, semi-transparent views of an exemplary inductively coupled plasma (ICP) chamber with a three-phase rotating crossflow according to one embodiment. As shown in Figure 2N, ICP chamber 280 includes an electrode 282 in the form of a planar, multi-spiral coil adjacent to the chamber lid (not shown). Electrode 282 includes RF-driven posts 286 and may include three grounded ends 284 along its maximum radius. Figure 2O shows gas injectors 288 symmetrically positioned around the periphery of the chamber lid. In one embodiment, gas injectors 288 may include 60°-wide inlets with 60°-wide spaces between them. FIG. 2P shows pump ports 290 arranged symmetrically around the circumference of the bottom of the chamber, with each pump port located diametrically 180° opposite one of the gas injectors 288 .

[0057] 3A-3F illustrate top views of a plasma processing chamber having a four-phase rotational crossflow process according to one embodiment. Figure 3A illustrates a plasma processing chamber 300 that may have a square shape with four sidewalls 312. Each of the four sidewalls 312 includes one of four gas injector arrays 318A-318D and one of four pump ports 320A-320D opposite the four sidewalls 312.

[0058] FIG. 3B illustrates a four-phase rotary crossflow process. In a four-phase cycle, gas is injected through each of the four sidewalls 312 and pumped out the opposite side. The conductance of each pump port 320A-320D can be adjusted with a high-speed, individual throttle valve. Phase 1 represents the first gas flow from left to right. Phase 2 represents a clockwise rotation from top to bottom to the second gas flow. Phase 3 represents a clockwise rotation from right to left to the third gas flow. And Phase 4 represents a clockwise rotation from bottom to top to the fourth gas flow. In one embodiment, each phase can last from about 0.5 seconds to 60 seconds, depending on the application.

[0059] 3C and 3D illustrate a four-phase rotational crossflow process with intentionally non-uniform center and edge gas injection by opposing side port pumping, according to further aspects of the disclosed embodiment. In this embodiment, the individual gas injectors in each of the gas injector arrays 318A-318D can be switched on / off or have regulated flow rates controlled by the gas inlet valves 122. FIG. 3C shows an example of four phases of center-to-edge gas flow, where, in each phase, the gas flow injected from the center gas injector of each individual gas injector of the gas injector arrays 318A-318D has a higher flow rate relative to the edge gas injectors of the gas injector arrays 318A-318D. FIG. 3D shows an example of four phases of edge-to-center gas flow. The gas flow injected from the edge gas injectors of each individual gas injector in each of the gas injector arrays 318A-318D has a higher flow rate relative to the center gas injectors in the gas injector arrays 318A-318D. Such non-uniform center and edge gas injection in the disclosed embodiments can be intentionally varied and controlled over time to control workpiece process uniformity. In one embodiment, the relative center and edge flows of one or more of the gas injectors are varied during a cycle, between cycles, or between sets of cycles.

[0060] FIG. 3E illustrates one phase of a multiphase (e.g., four-phase) rotational crossflow process in which at least a portion of the gas flow is diverted to the side of the workpiece rather than 100% crossflow across the workpiece. In this extreme case, the opposite pump port is closed while the side pump port is open, minimizing gas flow and velocity across the center of the workpiece. This process can be used to control uniformity. In embodiments, such diverted gas flow as shown in FIG. 3E is used for the entire process, or only part of a cycle, or for one or fewer sets of cycles in the process scheme. In embodiments, the diverted gas flow is rotated around the chamber for one or many cycles.

[0061] FIG. 3F illustrates one phase of a multiphase cycle in which gas flow is directed across the workpiece using smaller pump ports. As in FIG. 3C, gas flow from the center gas injector of each individual gas injector array has a higher flow rate relative to the gas injectors at the edge of the gas injector array, with the opposite pump ports open, while the other ports are closed. In a further embodiment, smaller pump ports, compared to the previous embodiment, allow gas flow across the central region of the workpiece. In this embodiment, for a typical 300 mm wafer chamber, the smaller pump ports may have centerline radial arc length dimensions of 3.5 inches wide by 1 / 4 inches long. Meanwhile, the larger single pump port may have centerline radial arc length dimensions of 3.5 inches wide by 14 inches long. In general, the pump port should have dimensions or size appropriate for the flow conductance of the process application, while having a port width opening narrow enough to promote uniform "cross-flow" over the wafer from the gas inlet side of the chamber to the pump port side.

[0062] Figures 4A-4C show top-view time plots of the rotating gas flow in a three-phase rotating crossflow at 60° intervals. The arrows represent velocity magnitude vectors, and the contour lines represent pressure gradients. Snapshots of the gas flow at 0°, 60°, 120°, 180°, 240°, and 300° are shown. The graph in Figure 4C shows that the pressure at the gas injector and pump ports remains relatively constant over time and across the three phases.

[0063] The exemplary steps shown in Figures 4A-4C can be used individually or, more likely, in combination over repeated cycles to maximize process uniformity. This tunability allows for the formation of a uniform plasma without introducing geometric discontinuities (i.e., gas injection holes) and using gas injection and / or pumping at the peripheral boundary and outside the high-density plasma region as control inputs, minimizing drift and changes over time due to etching, wear, or coating of exposed plasma-facing surfaces, i.e., electrodes / showerheads with gas holes or gas nozzles. The use of rotationally regulated crossflow can allow for process uniformity control from the peripheral boundary of the chamber.

[0064] reactive ion etching As an exemplary application, plasma processing chambers may be used to perform precision reactive ion etching during semiconductor manufacturing.

[0065] 5 illustrates a cross-sectional view of a portion of a wafer including stacked memory devices processed by a plasma processing chamber with a rotating gas crossflow according to one embodiment. In one embodiment, an intermediate structure of a stacked memory device during fabrication is shown. In one embodiment, intermediate structure 400 comprises a 3D-NAND structure and includes a substrate 402, an alternating layer stack 404 on substrate 402, an interlayer dielectric (ILD) layer 406 on alternating layer stack 404, and a mask layer 408 on ILD layer 406. Alternating layer stack 404 may include alternating insulator layers 404A and 404B (e.g., silicon nitride, silicon oxide, etc.). Examples of ILD layer 406 may include spin-on glass (SOG), silicon dioxide, and silicon on nitride (SiON).

[0066] The mask layer 408 may have a pattern that defines the pattern of the integrated circuit and guides the deposition or removal of material from the wafer in subsequent patterning steps. In this example, reactive ion etching is performed by a plasma processing chamber to remove material between portions of the openings in the mask layer 408, forming openings 410 through the ILD layer 406 and the alternating layer stack 404 to the substrate 402. Here, the intersections of the openings 410 and the metal layer 404A may ultimately form memory cells. The gas flow injected by the plasma processing chamber (described above) can be customized to control both the uniformity of the etch depth and the uniformity of the aspect ratio (depth to width) of the openings 410. In one embodiment, one or more of the openings 410 may be etched to have a first aspect ratio through the ILD layer 406 and a second aspect ratio through the alternating layer stack 404. In embodiments, one or more of the openings 410 may have a varying aspect ratio, referred to as a bowing, through the alternating layer stack 404, as shown. In one embodiment, the openings 410 may be etched to have a high aspect ratio of greater than 8-1, 9-1, or 10-1. In embodiments, one or more of the openings 410 may also have a varying etch depth.

[0067] In embodiments, 3D-NAND ion etch applications may include the pillar etch, slit etch, peri contact etch, staircase contact etch, cell contact-1 etch, and cell contact-1 etch described above. In embodiments, aspect ratio, etch depth, and bowing characteristics may be parameters monitored by machine learning models, as described below.

[0068] Using Machine Learning (ML) Models to Control Plasma Processing Chambers with Multiphase Rotating Crossflows Configuring the above-described plasma processing chamber to produce a desired result on a workpiece (e.g., a wafer) requires a process recipe that includes a complex combination of many different individually controllable process parameters (i.e., knobs). Examples include gas flow mixture, gas pressure (mTorr), gas flow ramp open time (msec), gas flow time (msec), gas flow ramp close time (msec), etc.

[0069] To develop a process recipe for high-volume manufacturing (HVM), process engineers rely on their experience and expertise to identify a baseline recipe that can provide a rough approximation of the desired results on wafers. A Design of Experiments (DoE) is then generated around the baseline recipe, relying on the processing of a set of wafers (or coupons) to identify how the knobs interact. The results of the DoE may be interpreted by the process engineer to further refine the baseline recipe. Additional DoE may also be performed to converge on the desired results on wafers. This iterative process requires time and resources.

[0070] Furthermore, once a final process recipe is developed, chamber drift can occur during multiple process iterations on different wafers, causing on-wafer results to vary. Chamber drift can be the result of erosion of consumable parts of the chamber, degradation of components (sensors, lamps, etc.), deposition of by-product films on surfaces, etc. Therefore, even after an extensive recipe development process, further adjustments may be necessary.

[0071] As a result, recipe development and chamber baselining require time and resources. In particular, the process space available for tuning and optimizing a given process is so large that it is virtually impossible to empirically explore the entire process space within any reasonable time frame. Furthermore, due to the interactions between process parameters and their impact on process performance, it is extremely difficult to predict the combined effect of simultaneous changes in multiple process parameters by manually scanning one process parameter at a time.

[0072] A second aspect of the disclosed embodiments comprises a semiconductor manufacturing tool that utilizes one or more machine learning (ML) models to control a plasma processing chamber having a multi-phase rotating cross-flow. The ML models can be used to develop process recipes and / or process devices or workpieces. The ML models can couple input process parameters to device outputs.

[0073] In an embodiment, a method for controlling a process includes interrogating an ML model to control the timing of gas flow rotation. In an embodiment, a method for developing a semiconductor manufacturing process recipe includes selecting one or more device results and interrogating an ML model to obtain a process recipe recommendation suitable for obtaining the device results when processed by a plasma processing chamber having a multi-phase rotating crossflow. This may be referred to as feedforward process tuning. In an embodiment, the method may further include performing a design of experiments (DoE) on a set of wafers to verify the process recipe recommended by the ML model. DoE measurements may be obtained and used to modify the process recipe for future wafers for feedback process adjustment.

[0074] Additionally, the ML model is updated as on-tool performance becomes available while wafers are processing in the chamber, and can then update process recommendations or proactively modify recipes, which may be referred to as "on the fly" or real-time process adjustments.

[0075] Recipe changes can include intra-step recipe modifications, such as increasing the gas flow rotation frequency when etching the top of the wafer and decreasing it when reaching the bottom, or vice versa. Another example is an updated machine learning model modifying input parameters within a single rotation, such as slightly differentiating the etch depth at the beginning and end of a gas flow rotation when processing the stacked memory device of Figure 5. The updated ML model can provide accurate tracking of chamber drift, enabling process recipe modifications without extensive DoE of physical wafers or relying solely on the experience and knowledge of process engineers.

[0076] Thus, embodiments disclosed herein leverage the use of ML models to query the entire process space without the need to process physical wafers in a large-scale Design of Experiments (DoE), thus significantly reducing the time and resources spent on recipe development.

[0077] An ML model can be a model of a process space generated from a combination of statistical and physical models. As used herein, "process space" can refer to a multidimensional process space that maps process parameters to one or more device outcomes on a wafer. Process parameters, sometimes called knobs, are variables that can be controlled to control a process. For example, knobs or process parameters can include, but are not limited to, any combination of temperature, RF source power, bias power, gas pressure (mTorr), gas flow ramp open time (msec), gas flow time (msec), gas flow ramp close time (msec), gas flow fraction at various gas injectors, gas composition at various injectors, gas flow fraction to various injectors, gas flow rotation frequency, gas flow composition frequency, gas flow rate / velocity (pressure gradient), gas flow direction, gas rotation phase, electron / plasma density, plasma density gradient, electron temperature, ion current density, plasma potential, sheath electric field, electric potential, sheath electric field tilt angle, sheath electric field z-component, mass fraction, flux, and ion current density to the workpiece.

[0078] Device results may refer to measurable characteristics of features on a wafer after processing. For example, selected device results may include any combination of feature profile, layer thickness, thickness uniformity, layer material composition, composition uniformity, porosity, film stress, process uniformity across chambers within a facility (e.g., chamber matching), wafer-to-wafer uniformity, uniformity between different wafer lots, etc. During an etch process, selected device results may also include any combination of etch rate, etch or uniformity center-to-edge, etch rate uniformity azimuthal, etch feature uniformity (generally described by top-to-bottom critical dimension (CD)), tilt, bow, and mask remainder, VHF-low and VHF-high relative power levels, and, if applicable, gap. That is, device results are not limited to results on a single wafer. Each point in process space may be a representation of a set of process parameter values ​​and one or more device results produced by the set of process parameters.

[0079] In embodiments, a statistical model of the ML model may be constructed using DoE of actual wafers to populate a portion of the process space. An algorithm may then be used to extrapolate to the remainder of the process space. The physical model is based on real-world physical and chemical interactions that occur in the process chamber. Simulations of the physical and chemical interactions in the process chamber over a range of different process parameters may be used to generate the physical model. In embodiments, the physical model is integrated with the statistical model to provide the ML model. For example, the physical model may be used to fill in any gaps in the statistical model and / or to validate the extrapolated data points.

[0080] 6, a block diagram of an ML model-based processing tool 600 is shown, according to an embodiment. The processing tool 600 includes tool hardware 640 corresponding to the plasma processing chamber described above, a machine learning model server 620, a front-end server 660, and a control server 650.

[0081] In an embodiment, ML model server 620 may include statistical model 625 and physical model 627. Statistical model 625 and physical model 627 may be communicatively coupled to database 630 for storing input data (e.g., sensor data, model data, measurement data, etc.) used to build and / or update statistical model 625 and physical model 627.

[0082] In embodiments, the statistical model 625 may be generated from the physical DoE and may use interpolation to provide an extended process space model. The physical wafer being processed may be used to map process parameters to specific device results. The physical DoE may also be used to identify interactions between different process parameters. After data (metrology data, sensor data, process parameter data, etc.) for the physical wafer is provided, interpolation is used to fill in gaps in the process space. In embodiments, data such as metrology data may be obtained using an external tool communicatively connected to the ML model server 620 by a data link (e.g., a wired or wireless data link). The algorithm may include, but is not limited to, neural networks, deep learning, or other known techniques used for regression analysis (e.g., linear, partial least squares, Gaussian, polynomial, convolutional neural networks for regression, regression trees, etc.).

[0083] In an embodiment, the statistical model 625 may be provided as a module that is sold or licensed for use with a processing tool. That is, the physical DoE for the statistical model 625 may be performed by the processing tool manufacturer. In other embodiments, the statistical model 625 may be generated by performing a physical DoE in situ. In yet another embodiment, a general statistical model 625 may be provided by the tool manufacturer, and subsequent physical DoE may be performed in situ to provide calibration of the statistical model 625 to more closely model the specific processing tool under investigation.

[0084] In embodiments, the physical model 627 may be generated using real-world physics and chemistry relationships. For example, physical and chemical equations for various interactions within a processing chamber may be used to construct the physical model. The physical model 627 may also utilize chamber geometry or other chamber configurations to enhance the accuracy of the physical model 627. The physical model 627 may be the result of a simulation of the physical and chemical interactions within a processing tool across multiple different process parameters. The physical model 627 may be a module that is sold or licensed for use with a processing tool.

[0085] In embodiments, the physical model 627 and the statistical model 625 may be able to reference each other (as indicated by the arrows). The cross-referencing of the two models 627 and 625 allows for validation of each model and filling in any gaps in the individual models. In embodiments, the physical model 627 and the statistical model 625 may be combined to provide a more robust ML model.

[0086] As shown, the ML model server 620 may be integrated with the processing tool 600. For example, the ML model server 620 may be communicatively coupled to the front-end server 660 via a network connection, as indicated by the arrow. However, in other embodiments, the ML model server 620 may be external to the processing tool 600. For example, the ML model server 620 may be communicatively coupled to the processing tool 600, such as through an external network.

[0087] In an embodiment, the front-end server 660 may include a user interface 665 for the ML model server 620. The user interface 665 provides an interface for process engineers to utilize the ML modeling to perform various operations, such as recipe development or chamber baselining. In one embodiment, the user interface 665 may correspond to the user interface 142 of FIG. 1B.

[0088] The control server 650 may include a smart monitoring and control block 655. The smart monitoring and control block 655 may include modules for providing diagnostics and other monitoring of the processing tool 600. The modules may include, but are not limited to, health checks, sensor drift, fault recovery, leak detection, and the like. The smart monitoring and control block 655 may receive as input data from various sensors implemented in the tool hardware 640. The sensors may include standard sensors 647 typically present in a semiconductor manufacturing tool 600 to enable operation of the tool 600. The sensors may also include modeling sensors 645 that are added within the tool 600. The modeling sensors 645 provide additional information necessary for building highly detailed ML models. For example, the modeling sensors may include virtual sensors and / or witness sensors. The virtual sensors may utilize data obtained from two or more physical sensors and perform interpolation and / or extrapolation to provide additional sensor data not available from the physical sensors alone. In a particular example, the virtual sensors may utilize upstream and downstream pressure sensors to calculate the flow rate through a portion of the process tool, such as a gas cartridge. Generally, the modeling sensors may include any type of sensor, such as, but not limited to, a pressure sensor, a temperature sensor, a gas concentration sensor, etc. In an embodiment, the smart monitoring and control block 655 may provide data used by the ML model server 620. In other embodiments, output data from the various modeling sensors 645 may be provided directly to the ML model server 620. In one embodiment, the control server 650 may correspond to the controller 140 of FIG. 1B.

[0089] 7A, a flow diagram illustrating a process for generating an ML model, according to an embodiment, is shown. In an embodiment, input from a modeling DoE 715 is input to a statistical model engine 724. The modeling DoE 715 may include processing of multiple physical wafers. The DoE 715 may include various data sources that are fed to the statistical model engine 724. For example, metrology data 716 acquired during or after processing of the wafers may be provided to the statistical model engine 724. Additionally, sensor data 717 from sensors within the processing tool may be provided to the statistical model engine 724. Process parameters 718 (i.e., values ​​of various process parameters during processing of the wafers) may also be provided to the statistical model engine 724.

[0090] In an embodiment, statistical model engine 724 may be implemented as hardware and / or software suitable for analyzing various data sources and outputting statistical model 725. Statistical model engine 724 may utilize machine learning based on neural networks or any other known techniques used in regression analysis (e.g., linear, partial least squares, Gaussian, polynomial, convolutional neural networks for regression, regression traces, etc.) to interpolate a larger process space than is available from physical DoE data alone.

[0091] In an embodiment, a physical model engine 726 is used to generate the physical model 727. In an embodiment, the physical model engine 726 may be implemented as hardware and / or software. The physical model engine 726 takes the chamber configuration and real-world physical and chemical equations as input. The physical model engine 726 may perform simulations of the physical and chemical interactions within the processing tool across multiple different process parameters to build the physical model 727. In this manner, changes to the process parameters that modify the physical and / or chemical reactions within the processing tool may be mapped to expected device results.

[0092] In embodiments, the statistical model 725 and the physical model 727 are used as inputs to generate the ML model 728. For example, the statistical model 725 and the physical model 727 may be inputs to the ML model engine 729. The ML model engine 729 processes the physical model 727 and the statistical model 725 and outputs the ML model 728. In some embodiments, the physical model 727 may be used to derive some physical measurement that cannot be measured. The output of the physical model 727 may be considered as an additional input to the statistical model. In such a situation, the ML model engine 729 adds information from the physical model 727 to the statistical model 725 to provide the ML model 728. Thus, the ML model 728 allows the two models 725 and 727 to be used to validate individual points in the process space, providing a more complete process space that can be individually tuned to a given processing tool. However, in some embodiments, the physical model 727 and the statistical model 725 may be standalone models, depending on their outputs. That is, in some embodiments, the statistical model 725 and the physical model 727 may not be merged into the ML model.

[0093] In embodiments, the ML model may also be considered another instance of the statistical model 725. For example, in FIG. 7B , the physical model 727 output by the physical model engine 726 may be used as an input to the statistical model engine 724. Thus, the statistical model engine 724 has an additional input to generate the statistical model 725 that includes information from the physical model 727. Notably, the statistical model engine 724 may already include data from the physical model 727, and using the ML model engine to generate the ML model may not be necessary in all embodiments.

[0094] 8, a flow diagram illustrating a process 870 for developing a process recipe using an ML model is shown, according to an embodiment. A target process recipe is a process recipe having a set of process parameters that produces a desired device result on a wafer. In an embodiment, process 870 may begin with step 871, which includes determining the desired device result. In an embodiment, the device result may relate to wafer device dimensions, material composition, etc. For example, the device result may include the thickness of a layer of a stacked memory device shown in FIG. 5, the thickness uniformity across the wafer, the material composition of the layer, or the material composition uniformity.

[0095] In an embodiment, process 870 may continue with step 872, which includes querying an ML model to select a set of process parameters. In an embodiment, the ML model may be a model of the process space generated from a combination of statistical and physical models. The statistical model may be generated using DoE of actual wafers, as described above. The physical model may be based on real-world physics and chemical equations. For example, the physical model may be generated from simulations of physical and chemical interactions within a processing tool across multiple different process parameters. In an embodiment, the ML model may cover the entire process space available to the processing tool.

[0096] The ML model allows for the identification of stable process recipes without relying solely on the experience and knowledge of the process engineer. Instead, a baseline recipe can be selected from the ML model's process space that is expected to produce device results that closely match those of the target device.

[0097] In an embodiment, process 870 may continue at step 873, which includes running a small DoE to validate the model recommendations. Due to the high accuracy of the ML model, only a small DoE (e.g., 20 wafers or less) may be required to validate the model recommendations. In an embodiment, the DoE may be designed by the process engineer. In another embodiment, the DoE may be designed using the ML model.

[0098] In an embodiment, process 870 may continue at step 874 with measuring the DoE wafer results with one or more metrology tools. The metrology data can be used to verify that target device results were achieved on the wafer.

[0099] In an embodiment, process 870 may continue at step 875, which includes determining whether the desired device results have been achieved. If the desired device results have been achieved, the process proceeds to step 876, where the process is complete. If the desired results have not been achieved, the process may repeat or feed back to step 872. In an embodiment, data from a small DoE may be fed back to the ML model to update the ML model. For example, if the process iteratively returns to step 872, the next DoE performed in step 873 may be designed based on additional knowledge learned from the DoE performed in the previous cycle and based on knowledge of where the ML model is deficient (e.g., for a particular process or plasma chamber). The updated ML model may then be queried to provide a second baseline recipe. In this way, even if the first iteration is unsuccessful, the process may still quickly converge to a suitable recipe without requiring extensive DoE and wasting resources.

[0100] 9 , a flow diagram illustrating a process 980 for baselining a processing tool is shown, according to an embodiment. In an embodiment, the baseline process may be useful to account for chamber drift during processing of wafers in the processing tool. In an embodiment, the baseline process may be performed at any desired frequency. For example, process 980 may be performed every lot, every planned maintenance (PM) event, or when device results for processed wafers are outside of specified ranges.

[0101] In an embodiment, process 980 may begin at step 981 with performing limited DoE of wafers using external metrology to baseline chamber performance. In an embodiment, the limited DoE may include 20 or fewer wafers. The limited DoE may utilize a recorded process recipe as a baseline. The external metrology may include any metrology suitable for determining device results on processed wafers. For example, in the case of an oxidation process, ellipsometry may be used to investigate film thickness and thickness uniformity across the wafer.

[0102] In an embodiment, process 980 may continue with step 982, which includes adding device results and other metrology data to the ML model. The additional data added to the ML model may be referred to as a calibration data set. The calibration data set is used to update the ML model so that it more accurately reflects the current conditions of the processing tool. For example, process 980 may include step 983, which includes adjusting the model predictions to account for specific chamber conditions. That is, the process space of the ML model is updated to more closely match the conditions of the processing tool under investigation.

[0103] In embodiments, the ML model may be a model of the process space generated from a combination of statistical and physical models. The statistical model may be generated using DoE of actual wafers, as described above. The physical model may be based on real-world physics and chemical equations. For example, the physical model may be generated from a simulation of physical and chemical interactions within a processing tool, such as a plasma processing chamber with a rotating crossflow, across multiple different process parameters. In embodiments, the ML model may cover the entire process space available to the processing tool.

[0104] In embodiments, process 980 may continue with step 984, which includes predicting optimized process parameters to achieve the desired wafer results for wafers subsequently processed in the chamber. The optimized process parameters may be selected after the ML model has been updated to include the calibration data set. Thus, the new process recipe provides wafer parameters that result in wafer results that more closely match the target values, despite changes in chamber conditions. In this manner, chamber drift may be monitored and accounted for to maintain tight process windows and improve uniformity, repeatability, and yield. Furthermore, the process recipe may be precisely adjusted to account for chamber drift, thereby reducing unscheduled tool downtime. Furthermore, if PM occurs, process 980 may be implemented to reduce recovery time and increase tool utilization.

[0105] In embodiments, the ML model can also be used to provide continuous (or near-continuous) modification of the process recipe to account for chamber drift. For example, wafer and process data acquired during processing of device wafers can be acquired and used to update the ML model. That is, a dedicated DoE may not be required to provide a calibration data set. Wafer data from device wafers can be acquired for all wafers or for a subset of wafers being processed.

[0106] Such embodiments may include providing an ML model of the processing tool. The ML model may include statistical and physical models similar to the ML models described above. In embodiments, the process may begin with a recipe being executed in a processing tool to process a first wafer. After processing the first wafer, wafer data from the first wafer and process data from the processing tool related to the execution of the recipe may be acquired. In embodiments, the wafer data may include metrology data such as, but not limited to, thickness, thickness uniformity, and profile. In embodiments, the process data may include data obtained from sensors in the processing tool and / or tool configuration information. In embodiments, the wafer data and process data are provided to the ML model to generate an updated ML model. In embodiments, the updated ML model is used to generate a modified recipe that accounts for chamber drift in the processing tool. Embodiments may then include running the modified recipe in the processing tool to process a second wafer. While the processing of a single first wafer is described above, it should be understood that multiple first wafers may be processed before an updated ML model is generated. In such embodiments, multiple sets of wafer data and process data may be used to generate the updated ML model.

[0107] FIG. 10 shows a diagrammatic representation of a machine in the exemplary form of a computer system 1000 upon which a set of instructions for causing the machine to perform any one or more of the methodologies described herein may be executed. In alternative embodiments, the machine may be coupled (e.g., networked) to other machines in a local area network (LAN), an intranet, an extranet, or the Internet. The machine may operate in the role of a server or a client machine in a client-server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The machine may be a personal computer (PC), a tablet PC, a set-top box (STB), a web appliance, a server, a network router, switch, or bridge, or any machine capable of executing a specified set of instructions (sequential or otherwise) that specify actions to be taken by the machine. Furthermore, while only a single machine is illustrated, the term "machine" should also be interpreted to include any collection of machines (e.g., computers) that individually or cooperatively execute a set (or sets) of instructions to perform any one or more of the methodologies described herein.

[0108] The exemplary computer system 1000 includes a processor 1002, a main memory 1004 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM) such as synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM), etc.), a static memory 1006 (e.g., flash memory, static random access memory (SRAM), MRAM, etc.), and a secondary storage device 1018 (e.g., a data storage device), which communicate with each other via a bus 1030.

[0109] Processor 1002 represents one or more general-purpose processing devices, such as a microprocessor, a central processing unit, etc. More specifically, processor 1002 may be a Complex Instruction Set Computing (CISC) microprocessor, a Reduced Instruction Set Computing (RISC) microprocessor, a Very Long Instruction Word (VLIW) microprocessor, a processor implementing other instruction sets, or a processor implementing a combination of instruction sets. Processor 1002 may also be one or more special-purpose processing devices, such as an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a Digital Signal Processor (DSP), a network processor, etc. Processor 1002 is configured to execute processing logic 1026 to perform the operations described herein.

[0110] Computer system 1000 may further include a network interface device 1008. Computer system 1000 may also include a video display unit 1010 (such as a liquid crystal display (LCD), a light emitting diode display (LED), or a cathode ray tube (CRT)), an alphanumeric input device 1012 (e.g., a keyboard), a cursor control device 1014 (e.g., a mouse), and a signal generation device 1016 (e.g., a speaker).

[0111] The secondary memory 1018 may include a machine-accessible storage medium (or, more specifically, a computer-readable storage medium) 1032 having stored thereon one or more sets of instructions (e.g., software 1022) that embody any one or more of the methods or functions described herein. The software 1022 may reside, completely or at least partially, within the main memory 1004 and / or the processor 1002 while it is being executed by the computer system 1000, with the main memory 1004 and the processor 1002 also constituting machine-readable storage media. The software 1022 may also be transmitted or received over the network 1020 via the network interface device 1008.

[0112] Although the exemplary embodiment depicts the machine-accessible storage medium 1032 as a single medium, the term "machine-readable storage medium" should be interpreted to include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated caches and servers) that store one or more sets of instructions. The term "machine-readable storage medium" should also be interpreted to include any medium that is capable of storing or encoding a set of instructions that are executed by a machine and that cause the machine to perform any one or more of the methods of this disclosure. Thus, the term "machine-readable storage medium" should be interpreted to include, but is not limited to, solid-state memories, and optical and magnetic media.

[0113] According to an embodiment of the present disclosure, a machine-accessible storage medium has stored thereon instructions that cause a data processing system to perform a method for processing wafers using insights from an ML model and / or a method for updating or building an ML model.

[0114] An embodiment of a plasma chamber having a rotationally regulated crossflow is disclosed.

[0115] Embodiment 1 A plasma processing chamber includes one or more sidewalls. A support surface within the one or more sidewalls holds a workpiece. A first gas injector along the one or more sidewalls injects a first gas flow in a first direction generally parallel to and across a surface of the workpiece. A first pump port along the one or more sidewalls, generally opposite the first gas injector, pumps out the first gas flow. A second gas injector along the one or more sidewalls injects a second gas flow in a second direction generally parallel to and across the surface of the workpiece. A second pump port along the one or more sidewalls, generally opposite the second gas injector, pumps out the second gas flow. The first gas flow and the second gas flow comprise a process gas mixture, an independent gas injection (IGI) mixture, or both, where the process gas mixture and the IGI mixture comprise one or more of an etchant or deposition gas, a diluent gas, an oxidizing gas, a reducing gas, a halogen-containing gas, and another gas such as CO or COS.

[0116] Embodiment 2: The plasma processing chamber of embodiment 1, wherein the plasma processing chamber is configured to use first and second gas injectors and first and second pump ports to rotate the first and second gas flows laterally across the workpiece from one or more sidewalls to provide a multiphase rotational crossflow process, the multiphase rotational crossflow process including at least a two-phase cycle.

[0117] Embodiment 3. The plasma processing chamber of embodiment 1, wherein the shape of the one or more sidewalls is cylindrical, elliptical, square, or rectangular.

[0118] Embodiment 4. The plasma processing chamber of embodiment 1, wherein the first gas injector and the second gas injector are disposed in openings in the one or more sidewalls.

[0119] Embodiment 5: A chamber lid covering one or more side walls; a support pedestal including a support surface, the support pedestal being below the chamber lid and above the chamber floor and surrounded by one or more sidewalls; a processing region defined by the region between the chamber lid, the support pedestal, and the one or more sidewalls; 5. The plasma processing chamber of embodiment 4, further comprising:

[0120] Embodiment 6. The plasma processing chamber of embodiment 5, wherein the first gas injector and the second gas injector are disposed in one or more sidewalls between the chamber lid and the support pedestal.

[0121] Embodiment 7 A plasma processing chamber as described in embodiment 5, wherein the positions of the first pump port and the second pump port are vertically offset from the positions of the first gas injector and the second gas injector by a distance approximately equal to the distance between the bottom of the chamber lid and the support pedestal.

[0122] Embodiment 8. The plasma processing chamber of embodiment 5, wherein the first pumping port and the second pumping port are in a cavity between the one or more sidewalls and the support pedestal and above the chamber floor.

[0123] Embodiment 9. The plasma processing chamber of embodiment 5, wherein the first pump port and the second pump port are disposed within additional openings in one or more sidewalls between the chamber lid and the chamber floor.

[0124] Embodiment 10. The plasma processing chamber of embodiment 1, wherein the first gas flow and the second gas flow are switched on and off to control the rotation of the gas flows.

[0125] Embodiment 11. The plasma processing chamber of embodiment 2, further comprising a modulation function applied to a flow rate of at least one of the first gas flow and the second gas flow, or applied to an exit conductance caused by at least one of the first pump port and the second pump port.

[0126]

[0033] Embodiment 12. The plasma processing chamber of embodiment 11, wherein the regulating feature comprises one or more gas inlet valves for regulating a flow rate of at least one of the first gas flow and the second gas flow.

[0127] Embodiment 13: A plasma processing chamber as described in embodiment 12, wherein the one or more gas inlet valves are connected to one or more gas sources so that a single type of gas or a mixture of different types of gases is injected into the processing region during each rotation phase.

[0128] Embodiment 14: A plasma processing chamber as described in embodiment 12, wherein the first gas injector and the second gas injector apply a constant total gas flow to smoothly and sequentially inject gas flow across different sides of the workpiece in a complete cycle.

[0129] Embodiment 15. The plasma processing chamber of embodiment 1, further comprising one or more throttle valves for adjusting a pump port conductance or pressure of at least one of the first pump port and the second pump port.

[0130] Embodiment 16: A plasma processing chamber as described in embodiment 15, wherein one or more throttle valves operate smoothly between two states of conductance or pressure, and these states are cycled in a similar sequence as the first gas injector and the second gas injector.

[0131] Embodiment 17. The plasma processing chamber of embodiment 1, further comprising a top-down gas flow.

[0132] Embodiment 18: A plasma processing chamber as described in embodiment 1, wherein the first gas injector and the first pump port constitute a first injector-pump port pair, and the second gas injector and the second pump port comprise a second gas injector-pump port pair, and along a plane generally parallel to the orientation of the workpiece, the position of the first injector-pump port pair is offset 180° from the position of the second injector-pump port pair.

[0133] Embodiment 19. The plasma processing chamber of embodiment 18, further comprising a top-down gas flow.

[0134] Embodiment 20: A plasma processing chamber as described in embodiment 18, further comprising a third gas injector and a third pump port on the opposite side to provide a third injector-pump port pair and a three-phase rotational cross-flow process.

[0135] Embodiment 21: The plasma processing chamber of embodiment 20, wherein the first injector-pump port pair, the second injector-pump port pair, and the third injector-pump port pair are offset from each other by 120 degrees.

[0136] Embodiment 22: A plasma processing chamber as described in embodiment 20, wherein the first gas injector, the second gas injector, and the third gas injector are positioned at approximately 120° from each other, the first pump port, the second pump port, and the third pump port are positioned at 120° from each other, and the first pump port, the second pump port, and the third pump port are laterally distributed between the first gas injector, the second gas injector, and the third gas injector.

[0137] Embodiment 23: A plasma processing chamber as described in embodiment 20, further comprising a fourth gas injector and an opposite fourth pump port to provide four injector-pump port pairs and a four-phase rotating crossflow process.

[0138] Embodiment 24: A plasma processing chamber as described in embodiment 23, wherein the position of each gas injector-pump port pair along the circular side wall is offset from the position of an adjacent injector-pump port pair by an angle equal to a total of 360 degrees divided by the number of injector-pump port pairs.

[0139] Embodiment 25. The plasma processing chamber of embodiment 1, wherein at least one of the first gas injector and the second gas injector includes a single vent in one or more sidewalls.

[0140]

[0066] Embodiment 26. The plasma processing chamber of embodiment 1, wherein the first gas injector and the second gas injector comprise a gas injector array of individual gas injectors.

[0141] Embodiment 27: A plasma processing chamber as described in embodiment 26, wherein the individual gas injectors are distributed around the periphery of one or more side walls, and the sets of individual gas injectors are regulated by one or more gas inlet valves to form gas flows in various directions across the workpiece.

[0142] Embodiment 28. The plasma processing chamber of embodiment 1, wherein at least one of the first gas injector and the second gas injector comprises a gas injector array of individual gas injectors.

[0143] Embodiment 29: A plasma processing chamber as described in embodiment 28, further comprising a center-to-edge gas flow, wherein at least the first gas flow or the second gas flow injected from a center injector of an individual gas injector in the gas injector array has a higher flow rate relative to an edge injector in the gas injector array.

[0144] Embodiment 30: A plasma processing chamber as described in embodiment 28, further comprising an edge-to-center gas flow, wherein at least the first gas flow or the second gas flow injected from an edge injector of an individual gas injector in the gas injector array has a higher flow rate relative to a center injector in the gas injector array.

[0145] Embodiment 31: A plasma processing chamber as described in embodiment 28, further comprising at least four gas injector arrays and opposite pump ports, wherein at least the first gas flow or the second gas flow is directed to the side of the workpiece rather than across the workpiece by closing the opposite pump port and opening a pump port lateral to the pump port.

[0146]

[0036] Embodiment 32. The plasma processing chamber of embodiment 1, wherein the plasma processing chamber is used to perform reactive ion etching during semiconductor manufacturing.

[0147] Embodiment 33. A method for implementing a rotational gas crossflow in a plasma processing chamber. During a first phase, the steps include injecting a first gas flow with a first gas injector in a first direction generally parallel to and across a surface of the device, and pumping the first gas flow out of the plasma processing chamber with a first pump port, wherein the first gas injector is along one or more sidewalls of the plasma processing chamber at a first location and the first pump port is along the one or more sidewalls at a second location generally opposite the first gas injector. During a second phase, the step includes injecting a second gas flow with a second gas injector in a second direction generally parallel to and across the surface of the device, and pumping the second gas flow out of the plasma processing chamber with a second pump port, the second gas injector being along one or more sidewalls at a third location and the second pump port being along the one or more sidewalls at a fourth location generally opposite the second gas injector. The first and second gas flows include a process gas mixture, an independent gas injection (IGI) mixture, or both, and the process gas mixture and IGI mixture include one or more of an etchant or deposition gas, a diluent gas, an oxidizing gas, a reducing gas, a halogen-containing gas, and another gas such as CO or COS.

[0148]

[0072] Embodiment 34. The method of embodiment 33, further comprising consulting a machine learning (ML) model to control the timing of the first gas flow and the second gas flow.

[0149] Embodiment 35: The method of embodiment 34, further comprising selecting one or more device outcomes and developing a semiconductor manufacturing process recipe for the device by querying the ML model to obtain a process recipe recommendation suitable for obtaining the device outcome when processed by a plasma processing chamber having a rotating gas crossflow.

[0150] Example Embodiment 36. The method of embodiment 35, further comprising running a design of experiments (DoE) on the set of wafers to validate the process recipe recommended by the ML model.

[0151] Embodiment 37. The method of embodiment 35, further comprising receiving as a process recipe any combination of temperature, RF source power, bias power, gas pressure (mTorr), gas flow ramp open time (msec), gas flow time (msec), gas flow ramp close time (msec), gas flow fraction at various gas injectors, gas composition at various injectors, gas flow fraction towards various injectors, gas flow rotation frequency, gas flow composition frequency, gas flow rate / velocity (pressure gradient), gas flow direction, gas rotation phase, electron / plasma density, plasma density gradient, electron temperature, ion current density, plasma potential, sheath electric field potential, sheath electric field tilt angle, sheath electric field z-component, mass fraction atomic O, O flux, ion current density to the workpiece.

[0152] Embodiment 38 The method of embodiment 35, further comprising selecting any combination of feature profile, layer thickness, thickness uniformity, layer material composition, composition uniformity, porosity, film stress, process uniformity across chambers within a facility, wafer-to-wafer uniformity, and uniformity between different wafer lots as device results.

[0153] Embodiment 39 The method of embodiment 38, further comprising selecting any combination of etch rate, etch or uniformity center-to-edge, etch rate uniformity azimuthal, etch feature uniformity, slope, bow, and mask remaining as device results during the etching process.

[0154] Embodiment 40: The method of embodiment 33, further comprising baseline- ing the plasma processing chamber by performing a limited design of experiments (DoE) of wafers using external metrology to baseline chamber performance. Wafer results and metrology data from the limited DoE are added to an ML model as a calibration data set. The ML model includes statistical models and physical models. Model predictions are adjusted to account for specific chamber and / or wafer conditions identified by the limited DoE. Optimized process parameters are predicted to achieve desired wafer results for wafers processed in the plasma processing chamber.

[0155] Embodiment 41. Embodiments disclosed herein include a plasma processing chamber including one or more sidewalls. Within the one or more sidewalls are supports for holding a workpiece. A first gas injector is located along the one or more sidewalls at a first location. A first pump port is located along the one or more sidewalls at a second location generally opposite the first gas injector. A second gas injector is located along the one or more sidewalls at a third location, and a second pump port is located along the one or more sidewalls at a fourth location generally opposite the second gas injector. Dual very high frequency (VHF) RF plasma source power generators have VHF-high frequency f1 and VHF-low frequency f2 and are connected to at least one of the top electrode and the bottom electrode. Wherein f1 is sufficiently high to distribute a non-uniform plasma ion or electron density or reactant density over the workpiece, and f2 is sufficiently low to distribute a non-uniform plasma ion or electron density or reactant density over the workpiece with a center that is high and low. The multiphase rotating crossflow process includes at least a first phase and a second phase. The first phase includes injecting a first gas flow through a first gas injector in a first direction generally parallel to and transverse to the surface of the workpiece and pumping the first gas flow through a first pump port. The second phase includes injecting a second gas flow through a second gas injector in a second direction generally parallel to and transverse to the surface of the workpiece and pumping the second gas flow through a second pump port.

[0156] Embodiment 42: The plasma processing chamber of embodiment 41, further comprising a first gas valve connected to the first gas injector, a second gas valve connected to the second gas injector, a first pressure control valve connected to the first pump port, and a second pressure control valve connected to the second pump port.

[0157] Embodiment 43. The plasma processing chamber of embodiment 42, further comprising: a controller connected to the plasma processing chamber, the controller configured to initiate a first gas flow by fully opening the first gas valve and partially opening the second gas valve during a first phase, opening the first pressure control valve, and closing the second pressure control valve.

[0158] Embodiment 44. The plasma processing chamber of embodiment 43, wherein the controller is further configured to rotate the direction of gas flow by beginning to close the first gas valve near the transition between the first phase and the second phase, fully opening the second gas valve to begin the second phase, and partially opening the first gas valve, opening the second pressure control valve, and closing the first pressure control valve.

[0159] Embodiment 44. A non-transitory computer-readable medium having stored thereon software instructions that, when executed by a processor, cause the processor to rotate a cross-flow of gas within a plasma processing chamber by performing the following steps: during a first phase, the steps including injecting a first gas flow with a first gas injector in a first direction generally parallel to and across a surface of the device; and pumping the first gas flow out of the plasma processing chamber with a first pump port, the first gas injector being along one or more sidewalls of the plasma processing chamber at a first location and the first pump port being along the one or more sidewalls at a second location generally opposite the first gas injector. During the second phase, this step includes injecting a second gas flow in a second direction generally parallel to and across the surface of the device with a second gas injector, and pumping the second gas flow out of the plasma processing chamber with a second pump port, the second gas injector being along one or more side walls at a third location, and the second pump port being along one or more side walls at a fourth location generally opposite the second gas injector.

[0160] Example Embodiment 46. The non-transitory computer-readable medium of example embodiment 45, further comprising consulting a machine learning (ML) model to control the timing of the first gas flow and the second gas flow.

[0161] Embodiment 47: A non-transitory computer-readable medium as described in embodiment 46, further comprising: selecting results for one or more devices; and developing a semiconductor manufacturing process recipe for the devices by querying an ML model to obtain a recommendation for a process recipe suitable for obtaining the device results when processed by a plasma processing chamber having a rotating gas crossflow.

[0162] Embodiment 48. The non-transitory computer-readable medium of embodiment 47, further comprising running a design of experiments (DoE) on the set of wafers to validate the process recipe recommended by the ML model.

[0163] Embodiment 49. The non-transitory computer-readable medium of embodiment 47, further comprising receiving as a process recipe any combination of temperature, RF source power, bias power, gas pressure (mTorr), gas flow ramp open time (msec), gas flow time (msec), gas flow ramp close time (msec), gas flow fraction at various gas injectors, gas composition at various injectors, gas flow fraction towards various injectors, gas flow rotation frequency, gas flow composition frequency, gas flow rate / velocity (pressure gradient), gas flow direction, gas rotation phase, electron / plasma density, plasma density gradient, electron temperature, ion current density, plasma potential, sheath electric field potential, sheath electric field tilt angle, sheath electric field z-component, mass fraction atomic O, O flux, ion current density to the workpiece.

[0164] Embodiment 50: A non-transitory computer-readable medium as described in embodiment 47, further comprising selecting, as a result of the device, any combination of feature profile, layer thickness, thickness uniformity, layer material composition, composition uniformity, porosity, film stress, process uniformity across chambers within a facility, wafer-to-wafer uniformity, and uniformity between different wafer lots.

[0165] Embodiment 51 The non-transitory computer-readable medium of embodiment 50, further comprising selecting any combination of etch rate, etch or uniformity center-to-edge, etch rate uniformity azimuthal, etch feature uniformity, slope, bow, and mask remaining amount as device results during the etching process.

[0166] Embodiment 52. The non-transitory computer-readable medium of embodiment 45, further comprising: baseline- ing the plasma processing chamber by performing a limited design of experiments (DoE) of wafers using external metrology to baseline chamber performance. Wafer results and metrology data from the limited DoE to the ML model are added as a calibration data set, the ML model including statistical and physical models. Model predictions are adjusted to account for specific chamber and / or wafer conditions identified by the limited DoE. Optimized process parameters are predicted to achieve desired wafer results for wafers processed in the plasma processing chamber.

[0167] Embodiment 53: A plasma processing chamber as described in embodiment 1 or 33, further comprising one or more conductance control rings for adjusting the conductance of the first pump port and the second pump port, the one or more conductance control rings being positioned adjacent to the first plasma screen and the second plasma screen above the first pump port and the second pump port, respectively.

[0168] Embodiment 54. The plasma processing chamber of embodiment 53, wherein the one or more conductance control rings include a first conductance control ring for the first pump port and a second conductance control ring for the second pump port.

[0169] Embodiment 55. A plasma processing chamber as described in embodiment 54, wherein the first conductance control ring and the second conductance control ring are independently moved vertically up and down by one or more actuators relative to the first plasma screen and the second plasma screen to close and open the first pump port and the second pump port.

[0170] Embodiment 56: A plasma processing chamber as described in embodiment 55, wherein a first conductance control ring and a second conductance control ring are positioned below the first plasma screen and the second plasma screen, and one or more actuators are positioned below the first pump port and the second pump port.

[0171] Embodiment 57 A plasma processing chamber as described in embodiment 55, wherein a first conductance control ring and a second conductance control ring are positioned above the first plasma screen and the second plasma screen in the processing region, and one or more actuators are positioned above the chamber lid.

[0172] Embodiment 58. A plasma processing chamber as described in embodiment 55, wherein one or more actuators are connected to a controller that synchronizes the vertical movement of the first conductance control ring and the second conductance control ring with the first gas flow and the second gas flow.

[0173]

[0062] Embodiment 59. The plasma processing chamber of embodiment 58, wherein the controller uses a machine learning model to set or control the first gas flow, the second gas flow, and the vertical motion.

[0174] Embodiment 60. The plasma processing chamber of embodiment 53, wherein the one or more conductance control rings include a single conductance control ring for both the first pump port and the second pump port.

[0175]

[0066] Embodiment 61. The plasma processing chamber of embodiment 60, wherein the conductance control ring comprises a circular disk shape having an opening.

[0176]

[0082] Embodiment 62. A plasma processing chamber as described in embodiment 61, wherein the conductance control ring is rotated by one or more actuators so that the openings are aligned with and open the currently active pump port.

[0177]

[0066] Embodiment 63. The plasma processing chamber of embodiment 61, wherein the one or more actuators are connected to a controller that synchronizes the rotational movement of the conductance control ring with the first gas flow and the second gas flow.

[0178]

[0066] Embodiment 64. The plasma processing chamber of embodiment 63, wherein a controller uses a machine learning model to set or control the first gas flow and the second gas flow and the rotational position of the conductance control ring.

[0179]

[0077] Embodiment 65. The plasma processing chamber of embodiment 61, wherein the conductance control ring has an outer diameter that approximately corresponds to the outer diameter of the processing region and an inner diameter that approximately corresponds to the diameter of the pedestal.

[0180]

[0077] Embodiment 66. The plasma processing chamber of embodiment 61, wherein the conductance control ring is positioned directly below and abutting the first and second plasma screens.

[0181]

[0067] Embodiment 67. A plasma processing chamber as described in embodiment 61, wherein the conductance control ring is positioned above and directly above the first plasma screen and the second plasma screen.

Claims

1. 1. A plasma processing chamber comprising: one or more side walls; a support surface within the one or more sidewalls on the pedestal for holding a workpiece within the processing region; a first gas injector along the one or more sidewalls for injecting a first gas flow in a first direction generally parallel to and across a surface of the workpiece; a first pump port along the one or more sidewalls generally opposite the first gas injector for pumping the first gas flow; a second gas injector along the one or more sidewalls for injecting a second gas flow in a second direction generally parallel to and across the surface of the workpiece, the second direction being different from the first direction; and a second pump port along the one or more side walls generally opposite the second gas injector for pumping the second gas stream; one or more conductance control rings for adjusting the conductance of the first pump port and the second pump port, the one or more conductance control rings being disposed adjacent to the first plasma screen and the second plasma screen above the first pump port and the second pump port, respectively; 1. A plasma processing chamber comprising:

2. 2. The plasma processing chamber of claim 1, wherein the one or more conductance control rings include a first conductance control ring for the first pump port and a second conductance control ring for the second pump port.

3. 3. The plasma processing chamber of claim 2, wherein the first conductance control ring and the second conductance control ring are independently moved vertically up and down by one or more actuators relative to the first plasma screen and the second plasma screen to close and open the first pump port and the second pump port.

4. 4. The plasma processing chamber of claim 3, wherein the first conductance control ring and the second conductance control ring are disposed below the first plasma screen and the second plasma screen, and the one or more actuators are disposed below the first pump port and the second pump port.

5. 4. The plasma processing chamber of claim 3, wherein the first conductance control ring and the second conductance control ring are positioned above the first plasma screen and the second plasma screen in the processing region, and the one or more actuators are positioned above a chamber lid.

6. 4. The plasma processing chamber of claim 3, wherein the one or more actuators are connected to a controller that synchronizes the vertical movement of the first conductance control ring and the second conductance control ring with the first gas flow and the second gas flow.

7. 7. The plasma processing chamber of claim 6, wherein the controller uses a machine learning model to set or control the first gas flow, the second gas flow, and the vertical movement of the first conductance control ring and the second conductance control ring.

8. The plasma processing chamber of claim 1 , wherein the one or more conductance control rings include a single conductance control ring for both the first pump port and the second pump port.

9. The plasma processing chamber of claim 8 , wherein the conductance control ring comprises a circular disk shape having an opening.

10. 10. The plasma processing chamber of claim 9, wherein the conductance control ring is rotated by one or more actuators such that the openings align with and open currently active pump ports.

11. 10. The plasma processing chamber of claim 9, wherein the one or more actuators are connected to a controller that synchronizes the rotational movement of the conductance control ring with the first gas flow and the second gas flow.

12. 12. The plasma processing chamber of claim 11, wherein the controller uses a machine learning model to set or control the first and second gas flows and the rotational position of the conductance control ring.

13. 9. The plasma processing chamber of claim 8, wherein the conductance control ring has an outer diameter that approximately matches an outer diameter of the processing region and an inner diameter that approximately matches a diameter of the pedestal.

14. 9. The plasma processing chamber of claim 8, wherein the conductance control ring is positioned directly below and abutting the first and second plasma screens.

15. 9. The plasma processing chamber of claim 8, wherein the conductance control ring is positioned above and directly above the first plasma screen and the second plasma screen.

16. 1. A method for implementing a rotational gas crossflow in a plasma processing chamber, comprising: during a first phase, injecting a first gas flow in a first direction generally parallel to and across a surface of a workpiece with a first gas injector and pumping the first gas flow out of the plasma processing chamber with a first pump port, the first gas injector being along one or more sidewalls of the plasma processing chamber at a first location and the first pump port being along the one or more sidewalls at a second location generally opposite the first gas injector; during a second phase, injecting a second gas flow in a second direction generally parallel to and across the surface of the workpiece with a second gas injector and pumping the second gas flow out of the plasma processing chamber with a second pump port, the second direction being different from the first direction, the second gas injector being along the one or more sidewalls at a third location, and the second pump port being along the one or more sidewalls at a fourth location generally opposite the second gas injector; using one or more conductance control rings to adjust the conductance of the first pump port and the second pump port, the one or more conductance control rings being positioned adjacent to first and second plasma screens above the first and second pump ports, respectively; A method comprising:

17. 17. The method of claim 16, further comprising providing the one or more conductance control rings as a first conductance control ring for the first pump port and a second conductance control ring for the second pump port.

18. 18. The method of claim 17, further comprising using one or more actuators to independently move the first and second conductance control rings up and down vertically relative to the first and second plasma screens to close and open the first and second pump ports.

19. 20. The method of claim 18, further comprising: disposing the first conductance control ring and the second conductance control ring below the first plasma screen and the second plasma screen; and disposing the one or more actuators below the first pump port and the second pump port.

20. 20. The method of claim 18, further comprising: disposing the first conductance control ring and the second conductance control ring above the first plasma screen and the second plasma screen in a processing region; and disposing the one or more actuators above a chamber lid.

21. 20. The method of claim 18, further comprising connecting the one or more actuators to a controller that synchronizes vertical movement of the first conductance control ring and the second conductance control ring with the first gas flow and the second gas flow.

22. 22. The method of claim 21, further comprising using a machine learning model by the controller to set or control the first gas flow, the second gas flow, and the vertical movement of the first conductance control ring and the second conductance control ring.

23. 17. The method of claim 16, further comprising providing the one or more conductance control rings as a single conductance control ring for both the first pump port and the second pump port.

24. 24. The method of claim 23, further comprising providing the conductance control ring in the shape of a disk having an opening.

25. 25. The method of claim 24, further comprising rotating the conductance control ring with one or more actuators so that the opening aligns with and opens a currently active pump port.

26. 25. The method of claim 24, further comprising connecting the one or more actuators to a controller that synchronizes rotational movement of the conductance control ring with the first gas flow and the second gas flow.

27. 27. The method of claim 26, further comprising using a machine learning model by the controller to set or control the first gas flow, the second gas flow, and the rotational position of the conductance control ring.

28. 24. The method of claim 23, further comprising providing the conductance control ring with an outer diameter that approximately matches the outer diameter of the processing region and an inner diameter that approximately matches the diameter of the pedestal.

29. 24. The method of claim 23, further comprising positioning the conductance control ring directly below and abutting the first and second plasma screens.

30. 24. The method of claim 23, further comprising positioning the conductance control ring above and directly above the first plasma screen and the second plasma screen.

31. 1. A plasma processing chamber comprising: one or more side walls; supports within the one or more side walls for holding a workpiece; a first gas injector along the one or more sidewalls at a first location; a first pump port along the one or more sidewalls at a second location generally opposite the first gas injector; a second gas injector along the one or more sidewalls at a third location; and a second pump port along the one or more sidewalls at a fourth location generally opposite the second gas injector; and one or more conductance control rings for adjusting the conductance of the first pump port and the second pump port, the one or more conductance control rings being disposed adjacent to the first plasma screen and the second plasma screen above the first pump port and the second pump port, respectively; The first and second gas injectors and the first and second pumping ports are configured to perform a multiphase rotating crossflow process in the plasma processing chamber, the multiphase rotating crossflow process comprising at least: a first phase including injecting a first gas flow in a first direction generally parallel to and across a surface of the workpiece with the first gas injector and pumping the first gas flow out with the first pump port; and a second phase including injecting a second gas flow with the second gas injector in a second direction generally parallel to and across the surface of the workpiece and pumping the second gas flow with the second pump port, wherein the second direction is different from the first direction.

1. A plasma processing chamber comprising:

Images