Immersion plasma source and process chamber for large-area substrates

Abstract

Embodiments disclosed herein include immersion inductively coupled plasma and capacitively coupled plasma excitation methods, apparatus, and processes for large-area substrates. The process chamber includes a pedestal for supporting a workpiece in the processing space, an array of inductors in a portion of the processing space above the pedestal, and a chamber top or lid above the array of inductors.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims priority to U.S. Patent Application No. 18 / 209,348, filed on June 13, 2023, the entire contents of which are incorporated herein by reference.

[0002] Embodiments of the present disclosure relate to the field of semiconductor processing, and more particularly, to immersion inductively coupled plasma and capacitively coupled plasma excitation methods, apparatuses, and processes for large - area substrates.

Background Art

[0003] Description of Related Art Conventional approaches to inductively coupling power to a plasma involve the implementation of an externally located energizing induction element (“coil”) disposed adjacent to a vacuum - atmosphere - structure dielectric window. In the case of large substrates, suitable materials (e.g., ceramics) can be expensive or unavailable, and there is a problem that the thickness must be increased, the distance from the coil to the plasma must be increased, and magnetic mutual coupling must be reduced, resulting in increased losses. Scaling up these sources results in non - uniformity and high - capacitance coupling.

Summary of the Invention

[0004] Embodiments disclosed herein include a process chamber that includes a pedestal for supporting a workpiece within a processing space. An array of induction elements is in a portion of the processing space above the pedestal. The array of induction elements includes a plurality of parallel and planar induction elements. A chamber top or lid is above the array of induction elements.

[0005] Embodiments disclosed herein include a process chamber that includes a pedestal for supporting a workpiece within a processing space. An array of induction elements is in a portion of the processing space above the pedestal. The array of induction elements has a rectangular loop configuration. A chamber top or lid is above the array of induction elements.

[0006] Embodiments disclosed herein include apparatus for inclusion within a process chamber. The apparatus includes an array of inductors comprising a plurality of parallel and planar inductors, wherein each of the plurality of parallel and planar inductors comprises a conductive rod or tube surrounded by a dielectric tube. [Brief explanation of the drawing]

[0007] [Figure 1A] This is a perspective view showing an array of rods / tubes for mounting in the upper region of a process chamber, according to one embodiment of the present disclosure. [Figure 1B] This is an end view of the array shown in Figure 1A, according to one embodiment of the present disclosure. [Figure 1C] This is an end view of the array shown in Figure 1A, according to one embodiment of the present disclosure. [Figure 2] This is a cross-sectional view of a process chamber, including an array of rods / tubes in a portion of the processing space, according to one embodiment of the present disclosure. [Figure 3A] This is a perspective view showing an array of rods / tubes for mounting in the upper region of a process chamber, according to one embodiment of the present disclosure. [Figure 3B] This is a perspective view showing another array of rods / tubes for mounting in the upper region of a process chamber, according to one embodiment of the present disclosure. [Figure 4A] This is a perspective view of a portion of a process chamber, including an array of rods / tubes in the processing space, according to one embodiment of the present disclosure. [Figure 4B] This is a perspective view of a portion of a process chamber, including an array of rods / tubes in the processing space, according to one embodiment of the present disclosure. [Figure 5A-5B] This is a top view of a portion of a process chamber, including an array of rods / tubes in a processing space, in which a workpiece rotates during processing, according to one embodiment of the present disclosure. [Figure 6A] This is a schematic diagram showing a parallel immersion ICP rod / tube array according to one embodiment of the present disclosure. [Figure 6B] This is another schematic diagram showing a parallel immersion ICP rod / tube array according to another embodiment of the present disclosure. [Figure 7] This is a schematic diagram showing a parallel immersion ICP rod / tube array according to one embodiment of the present disclosure. [Figure 8] This is a schematic diagram showing two parallel-fed opposing RF magnetic field (another embodiment) arrangements according to one embodiment of the present disclosure. [Figure 9] This is a schematic diagram showing two parallel-fed opposing RF magnetic field configurations according to one embodiment of the present disclosure. [Figure 10A] This is a perspective view of a rectangular loop immersion inductively coupled plasma (ICP) rod / tube arrangement according to one embodiment of the present disclosure. [Figure 10B] A side view of a rectangular loop immersion inductively coupled plasma (ICP) rod / tube arrangement according to one embodiment of the present disclosure. [Figure 11A] This is a top view of a plasma processing chamber having multi-stage rotary cross-flow operation according to one embodiment. [Figure 11B] This is a cross-sectional view of a plasma processing chamber according to a different embodiment. [Figure 11C] This is a cross-sectional view of a plasma processing chamber according to a different embodiment. [Figure 12] The diagram shows an exemplary form of a computer system according to one embodiment, in which a set of instructions can be executed that performs any one or more of the methods described herein. [Modes for carrying out the invention]

[0008] The disclosed embodiments relate to immersion inductively coupled plasma and capacitively coupled plasma excitation methods, apparatus, and processes for large-area substrates. The following description includes numerous specific details to provide a comprehensive understanding of the embodiments of the disclosure. It will be apparent to those skilled in the art that the embodiments of the disclosure can be carried out without these specific details. In other instances, well-known embodiments, such as the manufacture of integrated circuits, are not described in detail to avoid unnecessarily obscuring the embodiments of the disclosure. Furthermore, it should be understood that the various embodiments shown in the figures are illustrative and not necessarily drawn to scale.

[0009] According to one or more embodiments of the present disclosure, a method and apparatus for exciting a homogeneous plasma having properties suitable for material processing of large-area substrates, such as etching, deposition, or surface modification, is described. The embodiments may employ a pump-vacuum chamber equipped with an immersion array of dielectric-insulated inductive power coupling elements, a current distribution recursive transmission line feeding and return structure, a grounded chamber wall, RF-biasable substrate support electrodes, and a thermal conduction interface.

[0010] Embodiments may be implemented to provide plasma excitation for large-area substrate processing that overcomes practical problems: (1) limitations on RF dielectric window size in materials suitable for plasma processing, (2) plasma non-uniformity in large-area substrates due to distributed circuit (standing wave) effects, spatial fluctuations of voltage and current along the source, (3) minimizing capacitive coupling at unwanted surfaces (inductively coupled plasma (ICP) windows and ground electrodes), and (4) maximizing capacitive coupling at the substrate. Advantages of implementing the embodiments described herein may include overcoming the above problems.

[0011] To explain the background, the state-of-the-art approach has been to attempt to scale up a conventional flat coil or solenoid coil (circular or rectangular) on a single large RF dielectric window for large-area substrate processing. Success has been limited by (1) the availability and cost of large dielectric windows, which also have to be thickened and sized up (to withstand high atmospheric pressure / vacuum loading). Also, thickening the window moves the external coil element further away from the plasma, reducing the power coupling efficiency. Scaling up a conventional coil can result in standing waves (currents and voltages that vary with position along the coil element carrying current) in terms of the electrical length (the ratio of the wavelength in the plasma at the excitation frequency). This reduces the uniformity of power coupling and can reduce the uniformity of the plasma and the process. In addition, the long electrical length is also associated with high voltages in the coil element, and the capacitive coupling from the coil element across the dielectric window to the plasma becomes inappropriate. This unwanted capacitive coupling sacrifices the pursuit of inductive coupling and leads to the possibility of sputtering, etching, formation of contaminated films and microparticles due to higher-energy ion bombardment on the dielectric window surface (and possibly near the grounded chamber surface).

[0012] In other state-of-the-art approaches, attempts have been made to use multiple conventional flat coils or solenoid coils (circular or rectangular) on a single large RF dielectric window or multiple RF dielectric windows attached to a metal chamber frame. In such designs, uniformity has been a limiting factor.

[0013] Rods immersed in tubes within the plasma for a plasma source are implemented. State-of-the-art systems show that the rods / tubes in the array are arranged in series rather than in parallel, as described in relation to the embodiments herein. In such state-of-the-art arrangements, ohmic connections are made between adjacent rod ends, resulting in current paths following a “serpentine” pattern, and the currents in adjacent rods are approximately 180 degrees “out of phase”. The magnetic fields induced by the currents flowing on the surface of each rod are opposite to each other. These state-of-the-art systems typically operate at high frequencies (i.e., 13.56 MHz), and since the rods are separated in the plasma by at least several, or even many, skin depths under operating conditions, when the plasma is “on”, the induced magnetic fields do not destructively interfere with each other through the plasma. For rod / tube arrays sized for large-area substrate processing, several problems have been identified with such operation in the state-of-the-art approach. The voltage and current of each rod / tune element are not constant; that is, standing waves occur at high frequencies, and both current and voltage vary along the element. In addition, when elements are connected in series, the voltages are "added" between the elements, creating a voltage that varies spatially with respect to the plasma and ground. As a result, the inductive power coupling varies with respect to the position along each element and between elements in the chamber. Furthermore, the capacitive coupling to the plasma becomes large and varies along and between each element. This not only affects process uniformity but can also lead to sputtering or reactive ion etching of the tube dielectric, potentially causing contamination and particle formation problems in ceramic tubes in fluorinated plasmas, or consumable problems in quartz tubes. State-of-the-art approaches have attempted to mitigate the non-uniformity problem by operating in traveling wave mode, but this is a very complex solution. One approach might attempt to solve the sputtering problem of capacitively coupled tubes by using a Faraday (electrostatic) shield around the rods inside the tube. While this may be effective in suppressing capacitive coupling, it usually suffers from reduced efficiency due to the large shielding losses.In addition, the probability of arc discharge occurring between the energized rod and the adjacent electrostatic shield is high when using a long rod at high frequency (i.e., when the "electrical length" of the line is high), unless a large gap is used between them.

[0014] Embodiments described herein may be implemented to overcome state-of-the-art problems relating to plasma sources including series-connected rods / tubes immersed in plasma by reducing voltage and current fluctuations along the line (decreasing the "electrical length" of the line) and reducing the source frequency to reduce rod voltage. The problem found was that to avoid destructive interference in the plasma, the rods / tubes needed to be more widely separated within the array, because to deliver the same power under in-phase or out-of-phase conditions, the lower frequency rod currents had to be larger, thus significantly increasing power loss due to interference (reducing power coupling efficiency). Another problem with further separating the rods within the array is that the distance from the rod array to the substrate had to be increased to avoid "striped" or "ripple" patterns of plasma uniformity due to weakening of the plasma between the rods. Significantly increasing the distance from the rod array to the substrate increases the recombination of species generated near the power deposition region around the rods / tubes and transported to the substrate, altering the local chemical properties of the substrate.

[0015] In one embodiment, the substrate support pedestal is within the vacuum chamber, with its upper surface generally facing and being generally parallel to the inner ceiling surface of the vacuum chamber. The chamber walls are usually grounded and can be bare metal (usually aluminum), anodized, coated, or can employ a wall liner. The pedestal typically includes a monopole or multipole electrostatic chuck ("esc") that clamps a substrate (semiconductor, dielectric, or conductor) to its surface to facilitate heat conduction (temperature control) and power coupling (biasing), and to maintain the flatness and parallelism of the substrate with respect to the surface. Heat transfer fluid can be exchanged between the pedestal or the electrostatic chuck (ESC) and an external heat exchanger or chiller. A heat transfer gas can be supplied to the interface between the esc surface of the substrate and its back surface to facilitate heat conduction. The pedestal or ESC can include an electrical resistance heater with filtering insulation within its structure. The RF bias generator can be connected to the pedestal or ESC via a matching network and an optional transmission line. An electrostatic chuck voltage source can be connected to the ESC to establish and maintain the electrostatic clamping force (pressure) between the substrate and the ESC. The RF bias and the electrostatic chuck voltage can be connected to a common electrode with the ESC or to separate electrodes within the ESC. Alternatively, the chucking voltage of the ESC can be connected to the chuck electrode within the ESC, or the RF bias can be connected to the pedestal conductive electrode. In all these cases, filters can be employed to appropriately insulate the power or voltage or current sources from each other and to insulate the heater element from an external AC or DC power source. In one embodiment, the pedestal is in a fixed position with respect to the chamber. In another embodiment, the pedestal has a z-axis motion to facilitate substrate transfer between the transfer chamber and the robot blade. In another embodiment, the pedestal has an adjustable height to provide a selectable gap between the substrate pedestal and the rod / tube array in a process recipe or process operation to maximize process uniformity. In yet another embodiment, the pedestal can rotate or oscillate in the x-y plane to maximize process uniformity.

[0016] According to one embodiment of the present disclosure, the upper region of a process chamber includes a substantially parallel and substantially planar array of two or more conductive rods or tubes (hereinafter referred to as “inductive elements”), surrounded by a dielectric tube that functions as an RF window, with a gap of vacuum, air, gas, or liquid between the inductive elements and the inside of the dielectric tube. This array of rods and tubes penetrates the opposing walls of a substantially rectangular vacuum chamber and is sealed by the tubes at each end. The rods (inductive elements) are “powered” with RF current from a matched network via a recursive transmission line current splitting structure from one side, and optionally, on the opposite side, the rods are allowed to return current to a matched network or ground via a similar recursive transmission line current coupling structure. Capacitors(s) are used in series or parallel with the individual elements or the entire array to create a virtual ground region or to adjust impedance. In one embodiment, substantially planar and substantially parallel may include a range of non-planar and non-parallelism, e.g., non-parallel or non-planar at ±15 degrees, or two planes that are substantially parallel but not coplanar.

[0017] In one embodiment, the (conductive) pedestal and ESC may extend beyond the size of the substrate to maximize the uniformity of the sheath (boundary layer in the plasma) electric field on the substrate. The pedestal and ESC may be surrounded by a dielectric along one or more edges, and a grounded metal (uncoated or coated) may surround the dielectric. The process kit, dielectric, or semiconductor may cover the exposed portion of the ESC outside the substrate and extend over the surrounding dielectric region.

[0018] In one embodiment, gas can be introduced through one or more inlets or nozzles on the chamber ceiling or one or more chamber sides, and can be exhausted using a pump (or turbomolecular pump) in the central region below the pedestal or in the chamber bottom or other asymmetrical regions on one or more sides. If the pump port locations are non-central / symmetric, it may be advantageous to use a gas manifold or flow baffle to facilitate uniform pumping and pressure distribution. Multiple pump ports / pumps can also be employed, for example, at the four bottom corners, to create a quadruple-symmetric pump arrangement. Throttle valves and gate valves, or throttling gate valves, are typically employed in conjunction with pressure gauges (e.g., capacitance manometers) for chamber pressure control.

[0019] Alternative embodiments utilize a "cross-flow" configuration, where the gas inlet is generally located near one wall or side region (wall, ceiling, or bottom) of the chamber, and the pump is generally positioned on / near the opposite side / wall / bottom of the chamber, examples of which will be discussed later in relation to Figures 11A-11C. This configuration facilitates increased horizontal gas velocity and reduced gas residence time across the substrate, which may be suitable for some processes. The second inlet and the opposite outlet may be positioned 180 degrees rotated relative to the first set or each, and sequential or second-phase operation can alternate the flow direction. Finally, the inlets and outlets may be positioned on / near each side, with the inlets 90 degrees apart and each outlet facing the inlet. Four-phase operation can rotate the flow to achieve best uniformity in sequential or stepwise operation. Alternatively, best uniformity can be achieved by combining a single inlet on one side with an outlet on the opposite side in a rotating substrate pedestal.

[0020] In one embodiment, RF source power is coupled to a plasma source feeding structure and a return structure via a source matching network. A rod (inductor element) is "fed" with RF current from the matching network from one side via a recursive transmission line current splitting structure and grounded on or near the opposite side of the chamber. Alternatively, optionally, on the opposite side, the rod is configured to return current to the matching network or ground via a similar recursive transmission line current coupling structure. Capacitors(s) are used in series or parallel with individual elements or the entire array to create a virtual ground region or to adjust impedance or approximately resonant structure.

[0021] In one embodiment, for large substrates, the chamber size is generally selected with a considerably larger margin than the substrate. For a 0.5 × 0.5 m substrate, the size of the internal chamber may be selected to be 0.6 × 0.6 m or 0.7 × 0.7 m in x and y dimensions. It may also be preferable to make the chamber size even larger, for example, 0.8 × 0.8 m, or even larger, as best suited, i.e., 0.9 × 0.9 m. The chamber does not need to be square, but in one embodiment, in order to supply current in parallel, the rods / tubes should have equal lengths to each other and have approximately equal self-inductances under operating conditions in plasma. It should be understood that in the absence of plasma, the rods at the ends will have a larger and different inductance than the internal rods because adjacent rods are in close proximity to the walls. It should also be understood that the size of the peripheral area of ​​the pedestal housing relative to the size of the chamber should be considered when selecting the chamber size, as it defines the maximum area available for pumping (conductance).

[0022] In one embodiment, the plane of the rod / tube array is positioned substantially parallel to the chamber ceiling and the substrate support pedestal. The optimal height of the chamber is determined by both the gap between the rod / tube array and the substrate, and the gap between the rod / tube array and the chamber ceiling.

[0023] In one embodiment, in a parallel feeding configuration, the currents of adjacent rods are fed in "in phase" with constructive interference. In this parallel feeding configuration, the rods operate with the lowest current per rod, so the in-phase magnetic field creates the highest coupling efficiency (lowest losses). By operating at a lower frequency (compared to 13.56 MHz), voltage and current fluctuations along each rod are reduced (very small standing wave effect), and the total voltage generated across each rod for a given power is reduced. By driving the rods in parallel, the voltage does not "stack up" along the array of rods. Choosing parallel current feeding at this low frequency improves power coupling and the resulting plasma uniformity, and maximizes inductive coupling efficiency while minimizing capacitive coupling from the array. However, one problem may exist: how to feed the array and minimize the current fluctuations in each rod within the array. In one embodiment, there is simply a bus connecting all the rod ends on one side of the array together, and a second bus connecting all the rod ends on the opposite side of the array together, with the first side fed from an RF match and the second side on the opposite side grounded. This may be an improvement over having the first side fed from an RF match and the second side on the opposite side grounded, where the rods are “fed” with RF current from a matched network via a recursive transmission line current splitting structure from one side and grounded on the opposite side or nearby, or optionally, on the opposite side, the rods allow current to return to the matched network or ground via a similar recursive transmission line current coupling structure. Capacitors(s) are used in series or in parallel with individual elements or the entire array to create a virtual ground region or to adjust the impedance or approximately resonant structure. In one embodiment, series capacitors(s) placed in each rod current path or the entire current path may be adjusted to create a virtual ground (V=0) point, line, or region in a location within the chamber around the array. This may be useful for maximizing the symmetry of plasma uniformity. In one embodiment, capacitors(s) may be placed in parallel with one or both ends of each rod or the rod array, or in the RF matching output and return, to enable adjustment of the plasma load rod array impedance.Depending on the plasma conditions and the resulting load, it may be preferable to bring the plasma load rod array to near resonance at the drive frequency. This can reduce the current demand from the RF match and losses in the RF delivery system, potentially improving the power coupling efficiency to the plasma.

[0024] In one embodiment, in a parallel current supply configuration, a rod that is powered on one side and grounded (directly or indirectly) on the other side carries the primary return current in the chamber from the inner surface of the chamber.

[0025] In one embodiment, it was found that to further minimize capacitive coupling between the rod and the plasma (to minimize sputtering or etching of the tube and contamination / particle formation, or to reduce tube consumption), a larger gap between the rod radius and the tube inner radius can be selected by using a thinner-walled tube or by increasing the tube radius. In one embodiment, eight rod / tube elements were placed at 100 mm intervals in the center of a 0.85 × 0.85 m chamber, with an RF source frequency of 2 MHz, and 6.25 mm copper rods were used in dielectric tubes with an outer diameter of 12.5 mm and a wall thickness of 5 mm. In a more specific embodiment, the wall thickness is reduced to 4 mm. In a more specific embodiment, the outer diameter of the tube is increased to 18.25 mm and the tube wall thickness is 3 mm. The dielectric constant of the tube can also affect the capacitive coupling from the rod to the plasma. While quartz with an epsilon ratio of 4.2 provides lower capacitive bonding than, for example, aluminum oxide with an epsilon ratio of 9, quartz etches with volatile byproducts in fluorine-based etching, whereas aluminum oxide produces non-volatile byproducts such as aluminum fluoride, which can be problematic as it may form particles.

[0026] In one embodiment, a key factor in minimizing the reaction rate of a tube in a reactive plasma (e.g., an etching or cleaning plasma containing fluorine-based, other halogen-based, or hydrogen-containing species) is the surface temperature. In one embodiment, the copper rod is actually a tube, made of stainless steel and plated with copper (optionally with silver on top of the copper, to at least some skin depth of the metal upper layer at a driving frequency), and a flowing liquid is used to convectively cool the tube. In another embodiment, not only is the rod liquid-cooled, but the inner surface of the tube is further air-cooled by forced convection. In a specific embodiment, a dielectric liquid is used for forced convection of the inner wall of the tube, using a recirculating heat exchanger with a temperature-controlled fluid.

[0027] In one embodiment, the optimal distance from the rod / tube array to the substrate can be determined by several factors, including the spacing between the rods / tubes and the plasma composition (chemical properties, pressure). As mentioned above, if the spacing of the rod / tube array relative to the substrate is large, significant recombination of reactive species can occur from the location where seeds are generated near the power deposition region around the rods / tubes and transported to the substrate, potentially altering the local chemical properties of the substrate. If the spacing between the array and the substrate is too small relative to the spacing between the rods / tubes, the plasma between the rods will be weaker, potentially resulting in "striped" or "ripple" patterns in the plasma uniformity near the substrate. In one embodiment, when eight rod / tube elements are used in a 0.85 × 0.85 m chamber spaced 100 mm apart, the centerline distance of the rod / tube array relative to the substrate is selected to be 150 mm. Suitability can vary depending on the process application and plasma conditions. In some applications, it may be useful to have a pedestal with variable height capability to control the distance between the rod / tube array and the substrate for each recipe or process operation.

[0028] According to one embodiment of this disclosure, the effect of the distance from the rod / tube array to the chamber inside the ceiling was investigated by plasma modeling. This distance, as well as the resulting area and volume of the chamber, affects the power coupling of the rod / tube array to the plasma and the overall spatial dependence of the plasma species density and flux. In addition, the bias power applied to the cathode (substrate-supported pedestal) requires a return path distributed around the ground surface of the chamber, which is affected by the plasma density distribution. When the gap from the rod / tube array to the inside of the chamber ceiling is smaller than the gap from the rod / tube array to the bottom of the chamber (or substrate pedestal electrode), modeling investigations revealed that the lower the plasma species density (i.e., the number density of electrons and ions), the smaller the upper gap region and the larger the lower gap region. This can adversely affect the effective utilization of the upper chamber wall surface in the RF bias ground return path. When the upper and lower gaps are similar, or at least the upper gap is sufficiently large, the power coupling from the rod array to the upper and lower regions becomes more vertically symmetrical. As a result, the plasma number densities in the upper and lower regions are similar, and the upper chamber wall region is found to be more effectively involved in the RF grounding path. This may be suitable for maximizing the utilization of bias power as ion energy flux (power) at the smaller substrate pedestal electrode surface and as ion energy flux (power) at the larger chamber grounding electrode.

[0029] In one embodiment, using eight rod / tube elements spaced 100 mm apart in a 0.85 × 0.85 m chamber, when the centerline distance of the rod / tube array to the substrate was 150 mm, the centerline distance of the rod / tube array to the chamber ceiling varied from 50 mm to 150 mm. Under the selected etching conditions (5 kW source power at 2 MHz, 250 V with bias power at 13.56 MHz, pressure of 20 m Torr, 60% argon, 30% CF4, 10% O2), it was found that the larger the vertical symmetrical distance of the rod / tube plane with respect to the upper and lower chamber surfaces (upper part being the chamber ceiling, lower part being the substrate pedestal) (150 mm), the better the RF bias grounding path, resulting in a lower ion energy flux (ion power) to the grounded chamber surface and a higher ion energy flux to the substrate. The ion current and radical flux to the substrate were similar to those with a 50 mm upper spacing. Important species-dependent ion currents and radical species heterogeneity with respect to the substrate worsened slightly with increasing gap between the rod / tube array and the chamber ceiling, but were "good" in both cases.

[0030] In an alternative embodiment, the array of inductors is connected in phase by connecting the "far" end of the first rod to the opposite or "near" end of an adjacent rod, usually via an enclosure of shielded transmission lines outside the vacuum chamber. This creates a common-mode or auxiliary magnetic field, but uses a series wiring configuration.

[0031] Therefore, useful constructive interference occurs, but the voltage "stacks up" through the array, resulting in a high additional voltage. In the case of an 8-rod array, the voltage generated across the array is about 8 times that of an individual element, which may be undesirable from the standpoint of capacitive coupling. Nevertheless, at sufficiently low frequencies (the inductance reactance of the rods is proportional to the frequency), this may be the most useful and viable configuration under certain conditions. Advantages may include: (1) no special distribution device is required, the same current is used to feed all inductive elements (rods), the total current required for an 8-rod array is about 1 / 8th that of the parallel current feeding method (which may result in lower losses due to less demand on the RF match and power delivery system, and at low frequencies (i.e., 400 kHz), standing waves are minimal for typical dimensions of less than 1m x 1m, the voltage is acceptablely low, resulting in high inductive power coupling efficiency and acceptable inductive power coupling uniformity, and acceptable (minimal) capacitive coupling.

[0032] Optionally, in one embodiment, a Faraday shield can be used inside the tube's inner radius, resulting in lower voltages and a reduced risk of arc discharge due to the resulting lower "electrical length" of the rods at low frequencies. Capacitors(s) can be used in series or parallel with the series-wired array to create a virtual ground region or to adjust the impedance or approximate resonant structure. In one embodiment, series capacitors(s) placed throughout the current path can be adjusted to create a virtual ground (V=0) point, line, or region at a location within the chamber around the array. This can be useful for maximizing the symmetry of plasma uniformity. In one embodiment, capacitors(s) can be placed in parallel with one or both ends of the series-wired array of rods, or at the RF matching output and return, to allow adjustment of the plasma load rod array impedance. Depending on the plasma conditions and the resulting load, it may be useful to approximate resonate the plasma load rod array at the driving frequency. This can reduce current demand from the RF match and losses in the RF delivery system, potentially improving the power coupling efficiency to the plasma.

[0033] In one embodiment, if the Faraday shield is a described design, using a double-walled tube can provide better arc discharge prevention than leaving an air or gas gap between the rod and the Faraday shield. In such cases, cooling air, gas, or fluid may be forced to convect between the outer / inner tube walls.

[0034] In one embodiment, the plasma source and chamber described herein can be implemented to provide improvements to state-of-the-art methods, apparatus, and processes for low-pressure plasma etching, cleaning, deposition, or surface modification on large substrates, such as wafers with a diameter of 300 mm or more, and are particularly useful for large semiconductor and dielectric substrates, whether or not they are made of semiconductor or conductive (metallic) material, glass, glass-filled epoxy, or other organic material, and may be used for packaging.

[0035] As an exemplary array of rods / tubes, Figure 1A shows a perspective view of an array of rods / tubes for mounting in the upper region of a process chamber, according to one embodiment of the present disclosure. Figure 1B shows an end view of the array of Figure 1A, according to one embodiment of the present disclosure. Figure 1C shows an end view of the array of Figure 1A, according to one embodiment of the present disclosure.

[0036] Referring to Figures 1A, 1B, and 1C, the rod / tube array 100 includes a portion of the chamber space 102, for example, a portion of the chamber space above the workpiece being processed, with a plurality of rods / tubes 104. In one embodiment, 10 rods / tubes 104 are shown. It should be understood that other numbers of rods / tubes 104 may be used (e.g., less than 10 or more than 10). In one embodiment, the plurality of rods / tubes 104 are a plurality of substantially parallel rods / tubes 104 and substantially planar rods / tubes 104, as shown.

[0037] As an exemplary process chamber, Figure 2 shows a cross-sectional view of a process chamber, including an array of rods / tubes in a portion of the processing space, according to one embodiment of the present disclosure.

[0038] Referring to Figure 2, the process chamber 200 includes a pedestal 202 for supporting, for example, a workpiece, within the processing space 208. In one embodiment, the pedestal 202 is an electrostatic chuck. An array of rods / tubes 204 is included in a portion of the processing space above the pedestal 202. The top of the chamber or lid 206 is above the array of rods / tubes 204. A shaft 210 may be connected to the pedestal 202. In one embodiment, the array of rods / tubes 204 is a parallel and planar array, as described above in relation to Figures 1A, 1B, and 1C. In another embodiment, the array of rods / tubes 204 is a rectangular loop array, as described later in relation to Figures 10A and 10B.

[0039] As an exemplary array of rods / tubes, Figure 3A shows a perspective view of an array of rods / tubes for mounting in the upper region of a process chamber according to one embodiment of the present disclosure.

[0040] Referring to Figure 3A, the rod / tube array 300 for mounting in the upper region of the process chamber includes a frame 302 and a plurality of substantially parallel and planar rods / tubes 304 within the frame 302 (the closest rods / tubes are shown, for each rod / tube 304, showing a dielectric tube 304A surrounding an exemplary inductively coupled plasma rod 304B). A ground bus 306 is bolted to the side of the chamber, making continuous contact via an RF gasket (optional capacitors(s) connected in series between the ends of the ICP rods and ground are not shown). A recursive transmission line 308 is included for final current division. A recursive transmission line feeding structure 310 (lower) is included, with individual ground tubes around each vertical via removed from view for clarity. A recursive transmission line feeding structure 312 (upper) is connected to the recursive transmission line feeding structure 310 (lower). A capacitor bank 314 is connected to the recursive transmission line feeding structure 312 (upper). The RF matching output 316 is connected to the capacitor bank 314. The RF matching input 318, which is grounded, is also connected to the capacitor bank 314.

[0041] As another exemplary array of rods / tubes, Figure 3B shows a perspective view of an array of rods / tubes for mounting in the upper region of a process chamber according to one embodiment of the present disclosure.

[0042] Referring to Figure 3B, the rod / tube array 350 for mounting in the upper region of the process chamber includes several substantially parallel and planar rods / tubes 354 (the closest rods / tubes are shown, for each rod / tube 354, a dielectric tube 354A surrounding an exemplary inductively coupled plasma rod 354B). A ground bus 356 is bolted to the side of the chamber, making continuous contact via an RF gasket (optional capacitors(s) connected in series between the ends of the ICP rods and ground are not shown). A recursive transmission line 358 is included for final current division. A recursive transmission line feeding structure 360 ​​(bottom) is included, with individual ground tubes around each vertical via removed from view for clarity. A recursive transmission line feeding structure 362 (top) is connected to the recursive transmission line feeding structure 360 ​​(bottom). A capacitor bank 364 is connected to the recursive transmission line feeding structure 362 (top). An RF matched output 366 is connected to the capacitor bank 364. The RF matching input 368, which is grounded, is also connected to the capacitor bank 364.

[0043] As an exemplary process chamber, Figures 4A and 4B show a partial perspective view of a process chamber, including an array of rods / tubes in the processing space, according to one embodiment of the present disclosure.

[0044] Referring to Figure 4A, a portion of the process chamber 400 includes a support workpiece 404 surrounded by the chamber wall 402. An array of rods / tubes 350 (e.g., the array from Figure 3B) is included in a portion of the processing space above the support workpiece 404. Referring to Figure 4B, a portion of the process chamber 450 includes a pedestal 454 for supporting the workpiece 404 within the processing space. In one embodiment, the pedestal 454 is an electrostatic chuck. An array of rods / tubes 350 (e.g., the array from Figure 3B) is included in a portion of the processing space above the pedestal 454. A shaft 452 may be connected to the pedestal 454. In one embodiment, the array of rods / tubes 350 is a parallel and planar array, as described above in relation to Figures 1A, 1B, 1C, 3A, or 3B. In another embodiment, the array of rods / tubes is a rectangular loop array, as described later in relation to Figures 10A and 10B.

[0045] It should be understood that in some embodiments, the workpiece 404 is a fixed-position process. In other embodiments, the workpiece 404 rotates during processing. As an exemplary process, Figures 5A and 5B show a top view of a portion of a process chamber containing an array of rods / tubes in a processing space, according to one embodiment of the present disclosure, in which the workpiece rotates during processing.

[0046] Referring to Figure 5A, at the first position 500, the workpiece 506 is supported by a pedestal 504 surrounded by the chamber wall 502. The array of rods / tubes 508 is contained within a portion of the processing space above the pedestal 504. In one embodiment, the array of rods / tubes 508 is a parallel, planar array as described above in relation to Figures 1A, 1B, 1C, 3A, or 3B. In another embodiment, the array of rods / tubes is a rectangular loop array as described later in relation to Figures 10A and 10B. The array of rods / tubes 508 is aligned with the workpiece at this first position 500.

[0047] Referring to Figure 5B, the workpiece 506 rotates during processing, and a second position 550 is shown. The array of rods / tubes 508 is not aligned with the workpiece at this second position 550.

[0048] As described above, in one embodiment, a parallel immersion ICP rod / tube array is implemented. In one embodiment, the parallel immersion ICP rod / tube array is implemented to assist the RF magnetic field.

[0049] The ICP rod / tube array can be electrically driven in parallel from one side. As an example, Figure 6A is a schematic diagram 600 showing a parallel immersion ICP rod / tube array according to one embodiment of the present disclosure. Referring to Figure 6A, the chamber space 602 contains the ICP rod / tube array 603. The ground terminal 604 has a termination impedance, such as a capacitor (variable or fixed), either per rod or collectively. The RF source is connected to an RF matching network 608, which is connected to a recursive transmission line feeding structure 606 connected to the rods 603. The RF matching network 608 may include parallel elements for matching or to include external elements such as a capacitor bank.

[0050] As another example, Figure 6B is another schematic diagram showing a parallel immersion ICP rod / tube array according to another embodiment of the present disclosure. Referring to Figure 6B, in contrast to Figure 6A, it includes an external transformer with the primary connected in series and the secondary connected in parallel.

[0051] Referring to Figures 6A and 6B, according to one or more embodiments of the present disclosure, an auxiliary RF magnetic field electrically driven in parallel from one side may be driven (1) through a current splitter feed structure, where the current splitter feed structure is a recursive transmission line, (2) the other side is (locally) grounded through an ohmic connection to a chamber, (3) the other side is (locally) grounded through an impedance element, where the impedance element is a capacitor or inductor (fixed or variable), or the impedance element is an LC circuit (fixed or variable), or (4) the other side is grounded through a current combined turn structure, where the current combined turn structure is a recursive transmission line, where the current combined turn structure is grounded through an ohmic connection, or the current combined turn structure is grounded through an impedance element (where the impedance element is a capacitor or inductor (fixed or variable), or the impedance element is an LC circuit (fixed or variable)).

[0052] In another embodiment, a parallel immersion ICP rod / tube array is implemented to assist an RF magnetic field and is electrically driven in series. As an example, Figure 7 is a schematic diagram 700 showing a parallel immersion ICP rod / tube array according to one embodiment of the present disclosure. Referring to Figure 7, the chamber space 702 contains the ICP rod / tube array 703. The phase arrangement of the series feed includes a transmission line connection 704.

[0053] Referring to Figure 7, according to one or more embodiments of the present disclosure, an electrically series-driven auxiliary RF magnetic field may be driven at the first end of a first rod, the second end of the first rod being electrically connected to the first end of a second rod, the second end of the second rod being electrically connected to the first end of a third rod, and so on, with the second end of the last rod being grounded, (1) the second end of the last rod being (locally) grounded through an ohmic connection to a chamber, where the second end of the last rod is (locally) grounded through an impedance element connected to the chamber, where (a) the impedance element is a capacitor or inductor (fixed or variable), (b) the impedance element is an LC circuit (fixed or variable), or (2) the connection between the rod ends is made through a transmission line structure.

[0054] As described above, in one embodiment, a parallel immersion ICP rod / tube array is implemented. In one embodiment, the parallel immersion ICP rod / tube array is implemented to face an RF magnetic field.

[0055] The ICP rod / tube array can be electrically driven in parallel from both sides. As an example, Figure 8 is a schematic diagram 800 showing two parallel-fed opposing RF magnetic field (another embodiment) arrangements according to one embodiment of the present disclosure. Referring to Figure 8, the chamber space 802 contains the ICP rod / tube array 803. A termination capacitor 804 is at one end and a termination capacitor 806 is at the second end.

[0056] The ICP rod / tube array can be electrically driven from one side. As an example, Figure 9 is a schematic diagram 900 showing two parallel-fed opposing RF field configurations according to one embodiment of the present disclosure. Referring to Figure 9, the chamber space 902 contains the ICP rod / tube array 903. The grounded end of the coil rod is achieved by an optional termination capacitor 904. In one embodiment, a center-tapped transformer 906 is included.

[0057] According to other embodiments of the present disclosure, a rectangular loop immersion inductively coupled plasma (ICP) rod / tube arrangement is included in the processing space above the workpiece.

[0058] As an exemplary arrangement, Figure 10A is a perspective view of a rectangular loop immersion inductively coupled plasma (ICP) rod / tube arrangement 1000 according to one embodiment of the present disclosure, and Figure 10B is a side view.

[0059] Referring to Figures 10A and 10B, the chamber space 1002 contains a first rectangular rod / tube array 1004. A second rectangular rod / tube array 1006 is located above the first rectangular rod / tube array 1004. In one embodiment, the second rectangular rod / tube array 1006 is located together with the first rectangular rod / tube array 1004 from a top-down viewpoint, as shown.

[0060] With respect to the arrangements illustrated in Figures 10A and 10B, in one embodiment, for each substantially square coil, coil segments can be connected in series, with one single corner of each set having an input from an RF match and the adjacent corner being a ground point via an optional capacitor. Alternatively, each coil segment may have one of four parallel feeds from an RF match via a recursive transmission line current splitter network or a four-legged “spider” four-way transmission line splitter, and the distal end of each coil segment is grounded directly or via a capacitor. In either case, the current flowing through the segments can flow clockwise (or counterclockwise), similar to the type of RF field obtained from a square loop coil. In one embodiment, two “square” coils can be driven independently at the same or different frequencies. If driven at the same frequency, the phase difference can be controlled, although this may not be necessary. If driven at the same frequency, the two coils can instead be fed from a common match, and the current division between the coils can be controlled by a variable impedance element (e.g., a capacitor or inductor). In one embodiment, the coils are far enough apart that constructive or destructive interference is negligible (with RF frequencies ranging from 400 kHz to 40+ MHz, and a reasonable ICP-driven plasma electron density and practically usable low pressure for such a design, and a good skin depth). Embodiments may include additional "nested" coils. In embodiments, the coil segments do not need to form a square loop and may rather be rectangular. In embodiments, the current ratio (or power ratio) may be used to control the uniformity of the plasma or process from center to edge across a range of gas mixtures, pressures, and power outputs. Embodiments may include single, dual, or multi-loop configurations. Embodiments may include coil segments connected in series, with one corner of each set driven and its adjacent point grounded via an optional capacitor.

[0061] In another embodiment, there is a plasma chamber equipped with rotationally modulated crossflow. Such rotationally modulated crossflow can be used in combination with the above-described immersion inductively coupled plasma and capacitively coupled plasma excitation methods, apparatus, and processes for large-area substrates.

[0062] To explain the background, conventional plasma chambers (i.e., CCPs or ICPs) typically inject gas axially onto a workpiece from gas injection holes located symmetrically above or around the workpiece. This axially symmetric gas flow can result in pressure and concentration gradients, potentially leading to damage to the gas hole inlets and creating non-uniformity within the workpiece. Specifically, as wear occurs within gas holes located in a high-density, high-electric-field (|E|) plasma region, the shape of the holes changes, and as the plasma penetrates, these holes can alter the local plasma properties in their vicinity. In addition, these changes in shape can result in alterations in local gas flow rate and velocity. Consequently, showerheads need to be replaced relatively frequently, increasing the cost of the workpiece.

[0063] Accordingly, embodiments disclosed herein relate to plasma chambers (e.g., CCPs or ICPs) equipped with multi-stage rotational regulated gas crossflow 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 side wall. In a first stage, one of the gas injectors forces a gas flow in one direction, substantially parallel to and across the surface of a workpiece or device, and the gas is then discharged through a pump port. In a second stage, the gas flow is rotated using another gas injector, forcing the gas flow in a different direction, substantially parallel to and across the surface of the workpiece, and the gas is then discharged through another pump port. In another embodiment, gas injection valves connected to the gas injectors and / or throttle valves connected to the pump ports may be used to regulate the rotating gas flow.

[0064] In a plasma processing chamber equipped with a rotating, controlled gas crossflow, the need for showerheads (and gas injection holes) within a high-density, high-electric-field (|E|) plasma region is eliminated, thus preventing the causes of plasma non-uniformity. The disclosed embodiments prevent non-uniformity and time-varying plasma properties caused by plasma formation in gas holes due to approach to the high-density plasma or breakdown by the high electric field. In the disclosed embodiments, high pressure and concentration gradients between the center and the edges that would cause differences in processing between the center and the edges are avoided. To minimize plasma non-uniformity, the pressure distribution can be adjusted across the plasma space. In addition, in the disclosed embodiments, regions of poor flow and low gas velocity (i.e., the center of the workpiece) are eliminated for uniform removal of reactants and by-products.

[0065] Figures 11A to 11C show embodiments of a plasma processing chamber for a plasma reactor having multi-stage rotary cross-flow operation. Figure 11A shows a top view of a plasma processing chamber having multi-stage rotary cross-flow operation according to one embodiment. Figures 11B and 11C show cross-sectional views of plasma processing chambers in different embodiments.

[0066] Referring to both Figures 11A and 11B, the plasma processing chamber 1100A includes one or more chamber sidewalls 1112 and a support surface 1114 for holding a workpiece 1116 for processing (e.g., a semiconductor wafer, which may be a large substrate and / or a square substrate). The plasma processing chamber 1100 can be used to perform various processes on the workpiece 1116, such as etching, deposition, surface treatment, or material modification, by dispersing a gas inside the chamber. For example, the plasma processing chamber 1100A may include, but is not limited to, a plasma etching 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 vacuum processing chambers suitable for manufacturing various devices.

[0067] In one embodiment shown, one or more side walls 1112 surround a processing area 1110 in which a workpiece 1116 (e.g., a wafer or substrate) is processed. In the example shown, the plasma processing chamber 1100A is shown having an axially symmetric shape (e.g., cylindrical) resulting in a single cylindrical side wall 1112. However, in other embodiments, the plasma processing chamber 100A may have any other shape, such as an ellipse, which also results in a single side wall 1112, or it may have a shape as a square or rectangle, in which case the plasma processing chamber 1100A would have four side walls.

[0068] According to the disclosed embodiments, the plasma processing chamber 1100 includes at least two gas injectors 1118A and 1118B (collectively referred to as gas injectors 1118) and at least two pump ports 1120A and 1120B (collectively referred to as pump ports 1120) located generally along one or more side walls 1112. In one embodiment, the gas injectors are formed in openings that penetrate the liner of the side wall 1112. The plasma processing chamber 1100A may be configured to use the gas injectors 1118 and pump ports 1120 to rotate a gas flow 1124 laterally across a workpiece 1116 to provide multi-stage rotary cross-flow operation. In one embodiment, the multi-stage rotary cross-flow operation includes at least two-stage cycles, and may include three-stage cycles, four-stage cycles, and so on, where the gas for each stage is injected from one side of the plasma processing chamber 1100A and discharged from generally the opposite side. In this specification, the phrase "located generally along the sidewall(s)" is intended to mean that any of the gas injectors 1118 and / or pump ports 1120 may be located within the sidewall, or may be in contact with or adjacent to the sidewall in a horizontal direction, or may be located within the outer peripheral region of the upper or lower part of the chamber.

[0069] Rotating the gas flow laterally across the workpiece 1116 can result in improved control of gas velocity and pressure gradient, potentially leading to better process uniformity across and between wafers.

[0070] Referring to Figure 11B, the plasma processing chamber 1100A further includes a chamber lid 1104 on top of the side wall 1112. A support pedestal 1108 may include a support surface 1114 on which a workpiece 1116 is placed. In embodiments, the support pedestal 1108 and the support surface 1114 are fixed and not rotatable, and the workpiece 1116 fixed to the support surface 1114 does not rotate during processing. In one embodiment, the workpiece 1116 is electrostatically fixed to the support surface 1114. In another embodiment, the support surface 1114 is axially movable for adjusting the plasma gap or for wafer transfer. The processing area 1110 within the plasma processing chamber 1100A is defined by the area between the chamber lid 1104, the support pedestal 1108 (and support surface 1114), and the side wall 1112. The chamber floor 1106 is located below the side wall 1112 and below the processing area 1110. The support pedestal 1108 is located below the chamber lid 1104 and above the chamber floor 1106, and is surrounded by the side wall 1112. In one embodiment, the chamber lid 1104 and the support surface 1114 may be separated by a distance of approximately 50 mm to 400 mm. In one embodiment, the plasma processing chamber 1100A is a parallel-plate capacitively coupled plasma (CCP) process chamber with a first electrode 1105 above the workpiece 1116. A second electrode is contained within the location 1113 of the support pedestal 1108 below the support surface 1114. In one embodiment, the first electrode 1105 is coupled to an RF source having a power in the range of 200 to 10000 watts and a frequency in the range of 40 to 200 MHz. In one embodiment, the second electrode is coupled to ground. Plasma is generated above the wafer and between two electrodes. In one embodiment, the workpiece 1116 is electrostatically clamped to the support surface 1114 by one or more clamp electrodes inside or below the support surface 1114. In an embodiment, the workpiece 1116 is coupled to a bias electrode (for example, at a low RF frequency in the range of 0.1 to 20 MHz) for additional plasma control during processing.The generated plasma may be an ICP array as described in the embodiments herein, or may be pulsed during processing by pulsing power to a first electrode 1105 which may include an ICP array.

[0071] In one embodiment, the workpiece 1116 may include any substrate commonly used in a semiconductor manufacturing environment. For example, the workpiece may include a semiconductor wafer. In one embodiment, the semiconductor material may include, but is not limited to, silicon or a III-V semiconductor material. In some embodiments, the semiconductor wafer may be a Semiconductor-On-Insulator (SOI) substrate. Typically, semiconductor wafers have standard dimensions (e.g., 200 mm, 300 mm, 450 mm, or larger, and may be circular, square, or rectangular). However, it should be understood that the workpiece 1116 may have any dimensions. Embodiments may also include workpieces containing non-semiconductor materials such as glass or ceramic materials. In one embodiment, the workpiece 1116 may include a circuit or other structure manufactured using semiconductor processing equipment. In yet another embodiment, the workpiece 1116 may include a reticle or other lithography mask object.

[0072] Figures 11A and 11B show an example of a two-stage cycle rotational cross-flow operation. In the first stage, gas injector 1118A has opposing pump ports 1120A along one or more side walls 1112 generally opposite to gas injector 1118A for injecting a first gas flow 1124A in a first direction substantially parallel to and across the surface of workpiece 1116, and for discharging the gas flow 1124A. In the second stage, gas injector 1118B has opposing pump ports 1120B along one or more side walls 1112 generally opposite to gas injector 1118B for injecting a second gas flow 1124B in a second direction substantially parallel to and across the surface of workpiece 1116, and for discharging the gas flow 1124B. In this embodiment, the direction of the second gas flow 1124B is different from the direction of the first gas flow 1124A. In one embodiment, "approximately parallel" means within a range of approximately 0° to 15°, and "roughly opposite" means within a range of approximately 0° to 30°.

[0073] Therefore, gas injector 1118A and the opposing pump port 1120A form one gas injector pump port pair, and gas injector 1118B and the opposing pump port 1120B form a second gas injector pump port pair. In one embodiment, each of the gas injectors 1118A and 1118B may include an array of individual gas injectors, as shown in Figure 11A. In an alternative embodiment, each of the gas injectors 1118A and 1118B includes only a single vent gas injector. In some embodiments, gas injector 1118A includes an array of individual gas injectors and gas injector 1118B is a single vent gas injector, or vice versa.

[0074] As shown in Figure 11A, each gas injector-pump port pair (i.e., a gas injector and an opposing pump port) is symmetrically positioned along the side wall 1112 of the plasma processing chamber 1100A, along a horizontal plane substantially parallel to the orientation of the workpiece 1116. Any number of gas injectors 1118 and pump ports 1120 may be provided. To ensure even distribution of gas, generally, one gas injector-pump port pair may be offset from the location of adjacent injector-pump port pairs by an angle equal to the sum of 360 degrees divided by the number of injector-pump port pairs. For example, if there are two injector-pump port pairs, they are offset from each other by 180° (360° / 2). If there are three injector-pump port pairs, they are offset by 120°, and so on. In some embodiments, as shown, the span of the gas injector is smaller than the span of the corresponding pump port. In other embodiments, the span of the gas injector is the same as the span of the corresponding pump port. In other embodiments, the span of the gas injector is greater than the span of the corresponding pump port. Gas can be injected through gas injector openings of various external shapes, such as holes or slots, and different gas injectors may have the same or different external shapes and sizes.

[0075] In some embodiments, the number of gas injectors 1118 and pump ports 1120 may be equal, while in other embodiments, the number of gas injectors 1118 and pump ports 1120 may be different. In some embodiments, one pump port is associated with a corresponding gas injector, as shown. In other embodiments, an array of pump ports is associated with a corresponding gas injector.

[0076] As shown in Figure 11B, the gas injector 1118 is located within an opening in the side wall 1112 within the processing area 1110. For example, the opening may be located within the liner of the side wall 1112. In one embodiment, the opening in the side wall 1112 is located in a vertical position between the chamber lid 1104 and the substrate support pedestal 1108. In the shown embodiment, the opening in the side wall 1112 is adjacent to the bottom of the chamber lid 1104.

[0077] In one embodiment, the location of the pump port 1120 may be vertically offset from the location of the gas injector 1118 by a distance approximately equal to the distance between the bottom of the chamber lid 1104 and the top of the support pedestal 1108, along a vertical plane substantially parallel to the orientation of the support pedestal 1108. In this embodiment, the pump port 1120 may be located in a cavity above the chamber floor 1106 between the side wall 1112 and the support pedestal 1108. In another embodiment, the pump port 1120 may be located in an additional opening in the side wall 1112 somewhere between the chamber lid 1104 and the chamber floor 1106. In yet another embodiment, the gas may be injected from the outer peripheral region of the top of the chamber and / or discharged from the outer peripheral region of the bottom of the chamber, and may still flow over the workpiece processing area substantially parallel to the workpiece.

[0078] As described above, the plasma processing chamber 1100A of the disclosed embodiment injects gas across the workpiece 1116 substantially parallel to the workpiece 1116. This is in contrast to the typically axially symmetric top-down gas flow injection from "showerhead" electrodes in CCP source reactors, and the radial outward / downward gas injection from nozzle arrays near the central axis in ICP source or microwave source reactors. In addition, instead of pump ports or pump plenums located axially symmetrically around the outer circumference of the workpiece, in the embodiment, the gas is preferentially discharged from the side of the workpiece generally opposite to the injection side.

[0079] In one embodiment, the rotation of the gas flow can be controlled by switching the gas flow 1124 on or off at each cross-flow stage. In another embodiment, instead of switching the gas flow 1124 on or off, a control function can be applied to the flow rate of the gas flow 1124 from the gas injector 1118 and / or the outlet conductance (or pressure) generated by the pump port 1120 to approach an open / closed state or ramp between states using a modulation function such as a sine function. As shown in Figure 11B, the flow rates of one or both of the first gas flow 1124A and the second gas flow 1124B can be controlled using one or more gas injection valves 1122A and 1122B (e.g., piezoelectric valves) connected to the gas injectors 1118A and 1118B, respectively. In the embodiment, gas injection valves 1122A and 1122B are connected to one or more gas sources 1126, so that a single type of gas or a mixture of different types of gases can be injected into the processing area 1110 between each rotational stage. In one embodiment, a constant total gas flow can be applied by a gas injector 1118 to smoothly and continuously inject a gas flow across different sides of the workpiece 1116 in a complete cycle, which can then be repeated as needed.

[0080] In addition, in some embodiments, one or more of the pump ports 1120 can be adjusted. For example, the conductance (pressure) of a pump port can be adjusted using separate pressure control valves 1127A and 1127B for pump ports 1120A and 1120B. It is also shown that pump ports 1120A and 1120B are connected to one or more pumps 1132 to release gas. In the shown example, it is shown that the pressure control valve 1127A of pump port 1120A is in the closed position, and the pressure control valve 1127B is in the open position to release the first gas flow 1124A. The pressure control valves 1127A and 1127B can operate smoothly between two states of conductance or pressure, which are then circulated in a similar order to the gas injectors 1118A and 1118B. In one embodiment, the pressure control valves 1127A and 1127B include throttle valves.

[0081] The plasma chamber 1100A can be injected with various types of process gases. Exemplary process gases may include, namely, i) Dielectric etching gas containing one or more of CF4, C2F6, CHF3, C4F8, C4F6, C3F6, CH2F2, C3H2F4, NF3, SF6, ii) Deposit gas containing one or more of CH4, C2H2, and CH3F, iii) Additional gases for co-flow etching or deposition, including one or more of Ar, N2, O2, He, Kr, Xe, and COS. iv) Semiconductor material etching deposition gas containing one or both of SiCl4 and SiCH2Cl2, v) Hydride-based depositional gases containing one or more of BH3, AlH3, GaH3, and NH3, vi) Etching deposition gas for oxide materials containing one or more of SiCl4, SiCH2Cl2, and O2, vii) Annealing gas containing one or more of NH3, N2, and Ar It may include.

[0082] In some embodiments, the plasma processing chamber 1100A may further include sensors 1131 and systems for highly sensitive and real-time measurement and monitoring of process chamber conditions, including gas flow, velocity, pressure, and temperature. Specific embodiments may include capacitive wall sensors, on-chip or off-chip thermal sensors, pressure sensors, and / or integrated sensors (capacitive and thermal sensors) on substrates such as ceramic, glass, silicon, or flexible substrates. In some embodiments, sensors can be distributed throughout the chamber to monitor chamber conditions at various locations, which can then be correlated with overall process performance, such as etching rate, etching non-uniformity, particle generation, process drift, and pressure uniformity. In one embodiment, multiple pressure sensors or arrays of pressure sensors can be distributed throughout the chamber to provide data on the gas flow during processing (e.g., turnover rate, uniformity, velocity).

[0083] Figure 11B further shows that the plasma processing chamber 1100A can be connected to a controller 1140, and the controller 1140 can be connected to a user interface 1142. In some embodiments, the controller may be connected to a gas injection valve 1122, a pressure control valve 1127, a gas source 1126, a pump 1132, and a sensor 1131 to control the operation of the plasma processing chamber 1100A. The user can set process parameters and monitor the operation of the plasma processing chamber 1100A via the controller 1140 from the user interface 1142.

[0084] The multi-stage architecture of the plasma processing chamber allows for many different configuration options. For example, Figure 11C shows a cross-sectional view of a plasma processing chamber 1100B in an embodiment that includes a top-down gas flow, in addition to one or more pairs of gas injectors 1118 and pump ports 1120 that provide a side-to-side gas flow. In this embodiment, the chamber lid 1104 may be configured with a showerhead plate 1128 (for simplicity, the controller and UI in Figure 11B are not shown). The showerhead plate 1128 may have a central manifold 1129 and one or more outer manifolds 1130 for distributing gas into the processing area 1110, along with the gas distributed by the gas injectors 1118A and 1118B. While the showerhead plate 1128 can be used to introduce additional gas into the chamber with a vertical velocity component, the injection of gas from one side by the gas injector 1118A and the discharge from the other side of the workpiece 1116 by the pump port 1120B generally result in a horizontal component of gas velocity over most of the workpiece 1116. Similarly, the pump port 1120 may be on the side wall 1112, or on the top or bottom of the chamber, and the pump port 1120 is almost directly opposite the injection side. Thus, although there may be a vertical component of gas velocity exiting, the gas velocity is generally horizontal and parallel to the workpiece 1116 within the region above the workpiece 1116.

[0085] Figure 12 shows a graphical representation of a computer system 1200 in which a set of instructions for the machine to perform any one or more of the methods described herein may be executed. In alternative embodiments, the machine may be connected to (e.g., networked with) other machines on a local area network (LAN), intranet, extranet, or internet. The machine may operate as a server or 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), tablet PC, set-top box (STB), web appliance, server, network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) specifying the actions to be performed by that machine. Furthermore, although only a single machine is shown, the term “machine” should also be interpreted to include any collection of machines (e.g., computers) that individually or in conjunction execute a set of instructions (or sets of instructions) for performing any one or more of the methods described herein.

[0086] An exemplary computer system 1200 includes a processor 1202, main memory 1204 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM) (e.g., synchronous DRAM (SDRAM) or rhombus DRAM (RDRAM))), static memory 1206 (e.g., flash memory, static random access memory (SRAM), MRAM), and auxiliary memory 1218 (e.g., data storage devices), all communicating with each other via a bus 1230.

[0087] The processor 1202 represents one or more general-purpose processing devices, such as a microprocessor or a central processing unit. More specifically, the processor 1202 may be a complex instruction set computing (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, or a processor or combination of instruction sets that implements other instruction sets. The processor 1202 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), or a network processor. The processor 1202 is configured to execute processing logic 1226 for performing the steps described herein.

[0088] The computer system 1200 may further include a network interface device 1208. The computer system 1200 may also include a video display device 1210 (e.g., a liquid crystal display (LCD), a light-emitting diode display (LED), or a cathode ray tube (CRT)), an alphanumeric input device 1212 (e.g., a keyboard), a cursor control device 1214 (e.g., a mouse), and a signal generation device 1216 (e.g., a speaker).

[0089] The secondary memory 1218 may include a machine-accessible storage medium (or more specifically, a computer-readable storage medium) 1232 storing one or more instruction sets (e.g., software 1222) that embody any one or more of the methods or functions described herein. This software 1222 may also reside, all or at least partially, in the main memory 1204 and / or processor 1202 while being executed by the computer system 1200. The main memory 1204 and processor 1202 also constitute a machine-readable storage medium. The software 1222 may further be transmitted or received over the network 1220 via the network interface device 1208.

[0090] In exemplary embodiments, the machine-accessible storage medium 1232 is shown as a single medium, but the term “machine-readable storage medium” should be interpreted to include a single or multiple mediums that store one or more sets of instructions (e.g., a centralized or distributed database, and / or associated caches and servers). The term “machine-readable storage medium” should also be interpreted to include any medium that can store or encode a set of instructions executed by a machine, and by which the machine executes any one or more of the methods of the Disclosure. Accordingly, the term “machine-readable storage medium” should be interpreted to include, but not be limited to, solid-state memory, optical media, and magnetic media.

[0091] Embodiments of immersion-inductively coupled plasma and capacitively coupled plasma excitation methods, apparatus, and processes for large-area substrates are disclosed.

Claims

1. A plasma process chamber, A pedestal for supporting the workpiece in the processing space, An array of inductive elements within a portion of the processing space above the pedestal, comprising a plurality of parallel and planar inductive elements, The upper chamber or lid above the array of induction elements A plasma process chamber equipped with the following features.

2. The plasma process chamber according to claim 1, wherein an RF bias is applied to the pedestal relative to the chamber ground.

3. The plasma process chamber according to claim 1, wherein each of the plurality of parallel and planar inductive elements comprises a conductive rod or tube surrounded by a dielectric tube.

4. The plasma process chamber according to claim 3, wherein each of the plurality of parallel and planar inductive elements further comprises a Faraday shield or electrostatic shield between the conductive rod or tube and the dielectric tube.

5. The plasma process chamber according to claim 3, wherein the dielectric tube is cooled from the inside.

6. The plasma process chamber according to claim 1, wherein the array of inductive elements penetrates the walls of the process chamber that are opposite to each other.

7. The plasma process chamber according to claim 1, wherein the array of inductive elements is supplied with RF current from a matched network via a recursive transmission line current division structure from one side of the array of inductive elements.

8. The plasma process chamber according to claim 7, wherein the second side opposite the array of inductive elements is configured to allow current to return to the matched network or ground via a recurrent transmission line current coupling structure.

9. The plasma process chamber according to claim 1, further comprising one or more capacitors connected in parallel with the array of inductive elements.

10. The plasma process chamber according to claim 1, further comprising one or more capacitors connected in series with the array of inductive elements.

11. The plasma process chamber according to claim 1, wherein the array of inductive elements is configured to assist the RF magnetic field.

12. The plasma process chamber according to claim 1, wherein the array of inductive elements is configured to face an RF magnetic field.

13. The plasma process chamber according to claim 1, wherein the array of inductive elements is configured to be driven electrically in parallel.

14. The plasma process chamber according to claim 1, wherein the array of inductive elements is configured to be driven electrically in series.

15. The plasma process chamber according to claim 1, wherein the pedestal includes an electrostatic chuck.

16. A plasma process chamber, A pedestal for supporting the workpiece in the processing space, An array of inductors within a portion of the processing space above the pedestal, the array of inductors having a rectangular loop configuration, The upper chamber or lid above the array of induction elements A plasma process chamber equipped with the following features.

17. The plasma process chamber according to claim 16, wherein an RF bias is applied to the pedestal with respect to chamber grounding.

18. The plasma process chamber according to claim 16, wherein each inductor in the array of inductors comprises a conductive rod or tube surrounded by a dielectric tube.

19. The plasma process chamber according to claim 18, wherein each of the plurality of inductive elements further comprises a Faraday shield or electrostatic shield between the conductive rod or tube and the dielectric tube.

20. The plasma process chamber according to claim 18, wherein the dielectric tube is cooled from the inside.

21. The plasma process chamber according to claim 16, wherein the rectangular loop configuration is a single-loop configuration, a dual-loop configuration, or a multi-loop configuration.

22. The plasma process chamber according to claim 16, wherein the rectangular loop configuration comprises coil segments electrically connected in series or parallel.

23. The plasma process chamber according to claim 16, wherein the pedestal includes an electrostatic chuck.

24. Apparatus for inclusion within a plasma process chamber, An array of inductive elements comprising a plurality of parallel and planar inductive elements, wherein each of the plurality of parallel and planar inductive elements comprises a conductive rod or tube surrounded by a dielectric tube. A device equipped with the following features.

25. The apparatus according to claim 24, wherein the array of inductive elements is configured to be powered by RF current from a matched network via a recurrent transmission line current splitting structure from one side of the array of inductive elements, and the second side opposite the array of inductive elements is configured to return current to the matched network or ground via a recurrent transmission line current coupling structure.

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