Plasma processing device

Abstract

The utility model discloses a plasma processing device. The plasma processing device comprises a vacuum chamber and a base positioned in the vacuum chamber, the dielectric window is positioned at the top of the vacuum chamber and is opposite to the base; the coil is at least partially positioned above the dielectric window and comprises at least two lengthwise excitation sections; the radio frequency power supply is used for applying radio frequency signals to the coil, so that the current directions of the two excitation sections are the same, and the rotary driving device is used for driving the coil and / or the base to rotate, so that the coil and the base can rotate relatively in the technological process. The coil structure provided by the utility model can improve the distribution uniformity of an electromagnetic field and the utilization efficiency of a radio frequency power supply.

Description

Technical Field

[0001] The utility model relates to a plasma processing device, and more particularly to an inductively coupled plasma processing device. Background Art

[0002] Inductively coupled plasma (ICP) etching or deposition is a key process in the fabrication of semiconductor devices, including various microelectronic devices, thin-film photovoltaic cells, and light-emitting diodes. The basic process of plasma etching or deposition involves introducing a reactive gas from a source into a reaction chamber, where it ionizes and decomposes in the plasma to form ions and free radicals. These highly reactive particles are transported by the airflow to the surface of the object being processed, where they undergo a chemical reaction or reaction.

[0003] Inductively coupled plasma (ICP) chambers utilize coils to radiate radio frequency (RF) energy through a dielectric window into a vacuum chamber, thereby igniting the gas therein and maintaining the plasma. Typically, an ICP plasma chamber is provided with one or more annular or spiral coils as coils above the dielectric window at the top of the chamber. The magnetic field generated by such a circumferentially extended coil typically generates mutual inductance between coil portions of different radii, resulting in more RF energy being concentrated in the outer region of the coil, thereby causing non-uniformity in plasma density. In addition, the grounding or power terminals of the inductive coil are typically located at several points on the edge, and the location of these terminals may also result in non-uniform distribution of the plasma in azimuth. The non-uniformity in plasma density directly affects the uniformity of the surface treatment of the object to be processed. Summary of the Invention

[0004] The following summary of the present invention is intended to provide a basic understanding of certain aspects and features of the present invention. This is not an exhaustive overview of the present invention and is not intended to particularly identify key or critical elements of the present invention, nor is it intended to delineate the scope of the present invention. Its sole purpose is to present some concepts of the present invention in a simplified form as a prelude to the more detailed description below.

[0005] The utility model discloses a plasma processing device, comprising: a vacuum chamber; a base located in the vacuum chamber and used for carrying a substrate during a process; a dielectric window located at the top of the vacuum chamber and arranged opposite to the base; a coil located at least partially above the dielectric window and comprising at least two longitudinal excitation segments; a radio frequency power supply, applying a radio frequency signal to the coil so that the current directions of the two excitation segments are in the same direction; and a rotation drive device, used for driving the coil and / or the base to rotate so that the coil and the base can rotate relative to each other during a process.

[0006] Optionally, the electromagnetic fields generated by the two excitation segments are superimposed on each other, generating a longitudinal plasma distribution above the substrate.

[0007] Optionally, the multiple excitation segments of the coil are connected in series or in parallel.

[0008] Optionally, the two excitation segments are arranged parallel to each other.

[0009] Optionally, the length of the excitation segment is greater than the diameter of the substrate.

[0010] Optionally, the length of the excitation segment is greater than the diameter of the dielectric window.

[0011] Optionally, the coil includes at least two excitation segments and a return segment connecting two adjacent excitation segments, and the return segment and the excitation segment are located in different planes.

[0012] Optionally, the coil further includes a height connection section connecting the excitation section and the return section, wherein the height connection section enables the distance from the return section to the dielectric window to be greater than the distance from the excitation section to the dielectric window.

[0013] Optionally, the length of the height connection segment is greater than 1 / 2 of the length of the excitation segment.

[0014] Optionally, the excitation segment includes a central excitation segment and edge excitation segments located on both sides of the central excitation segment, and the distance from the central excitation segment to the dielectric window is greater than the distance from the edge excitation segment to the dielectric window.

[0015] Optionally, the return section includes a central return section and edge return sections located on both sides of the central section, and the distance from the central return section to the dielectric window is smaller than the distance from the edge return section to the dielectric window.

[0016] Optionally, the RF power supply supplies an RF signal to the coil via a contactless coupler, wherein the contactless coupler includes a transmitting end and a receiving end, wherein the receiving end is electrically connected to the input end of the coil, and the transmitting end is electrically connected to the RF power supply.

[0017] Optionally, the receiving end rotates synchronously with the coil, and the receiving end rotates relative to the transmitting end.

[0018] Optionally, at least one of the receiving end and the transmitting end is a ring conductor.

[0019] Optionally, the RF power supply supplies a RF signal to the coil via a brush.

[0020] Optionally, the lengths of the excitation segments are equal or unequal.

[0021] Optionally, the coil is connected to a rotating shaft, and the rotation drive device drives the rotating shaft to drive the coil to rotate.

[0022] Optionally, the rotation drive device is a motor.

[0023] Optionally, the dielectric window is dome-shaped, and the excitation segment of the coil is a curved segment.

[0024] Optionally, the dielectric window is cylindrical.

[0025] Aspects disclosed herein relate to an inductively coupled plasma chamber having a rotating coil or rotating pedestal, wherein RF power is transferred to the coil by implementing a contactless DC disconnect / RF short mechanism. The contactless DC disconnect / RF short mechanism creates an ohmic disconnect, preventing DC current flow while allowing RF power transfer. This configuration may be referred to herein as a contactless coupler or a contactless capacitive coupler.

[0026] The disclosed embodiments provide a contactless DC disconnect / RF short circuit mechanism having two physically separated electrical contacts, such that the contacts do not physically touch each other. The two electrical contacts are configured to create a DC disconnect while allowing RF power to flow, thereby creating an RF short circuit.

[0027] In a disclosed embodiment, a plasma processing chamber is provided, comprising: a vacuum chamber having a dielectric window; a coil provided around the dielectric window, the coil having an input terminal and at least one ground terminal; a motor connected to the coil for applying a rotational force to the coil; a radio frequency power supply; and a contactless coupler that receives radio frequency power from the radio frequency power supply and applies the radio frequency power through the input terminal of the coil.

[0028] The disclosed embodiment also includes a plasma processing chamber comprising: a vacuum chamber; a base located on the floor of the vacuum chamber and configured to support a substrate; a dielectric window located at the upper portion of the vacuum chamber; a coil arranged around the dielectric window, the coil comprising a plurality of straight excitation segments arranged parallel to the plane of the dielectric window, the plurality of straight excitation segments being parallel to each other and spaced apart to cause superposition of electromagnetic radiation from any two of the plurality of excitation segments; and a motor for causing relative rotation between the substrate and the coil. The plurality of excitation segments may have the same or different lengths. The plurality of excitation segments may be connected in series or in parallel. Current may flow in the same direction in all of the plurality of excitation segments. The coil may be connected to an RF power source via a capacitive coupler. The coil may also include a rotating shaft connected to the motor, and all of the plurality of excitation segments are connected to the rotating shaft. The coil may be connected to the RF power source via a capacitive coupler having a fixed contact and a rotating contact connected to the coil.

[0029] Aspects of the present invention relate to an apparatus for applying radio frequency (RF) energy to a processing chamber, comprising: a coil having a main shaft rotatable about a rotational axis, an input for receiving RF power, and an output connected to ground; a contactless coupler having a receiving connector connected to the coil input and a transmitting connector connected to an RF power source, the receiving connector and the transmitting connector configured to allow RF power to flow while providing a DC disconnect, the receiving connector being rotatable relative to the transmitting connector; and a grounding coupler connected between the coil output and ground. The grounding coupler allows RF power to flow while providing a DC disconnect. The receiving connector may include an inner conductive ring, while the transmitting connector includes an outer conductive ring concentric with the inner conductive ring, defining a separation space between the inner and outer conductive rings, thereby achieving capacitive coupling of RF energy between the inner and outer conductive rings. The inner conductive ring rotates with the coil, while the outer conductive ring is fixed. The apparatus may also include a dielectric ring located within the separation space and concentric with the inner conductive ring. The dielectric ring may be made of ceramic, Teflon, or other similar materials. The device may further include a bearing rotatably supporting the main shaft, and a motor connected to the main shaft and applying a rotational force to the main shaft.

[0030] The coil may include multiple excitation segments arranged in a horizontal plane. The multiple excitation segments may be connected in series to form multiple rectangular coils, and at least two of the multiple rectangular coils may have different lengths. The multiple excitation segments may also be connected in parallel, and at least two of the multiple excitation segments may have different lengths. The coil may also include multiple curved excitation segments arranged in a horizontal plane or in a dome shape.

[0031] Disclosed aspects include a plasma processing chamber comprising: a vacuum chamber; a pedestal located on a floor of the vacuum chamber; a dielectric window located above the vacuum chamber; a coil disposed about the dielectric window, the coil being attached to a rotatable shaft; a motor connected to the rotatable shaft; a radio frequency power source; and capacitively coupling radio frequency energy transmitted from the radio frequency power source to the coil via a contactless coupler, wherein the contactless coupler includes a capacitor having an input contact connected to the radio frequency power source and an output contact connected to the coil, the input contact being rotatable relative to the output contact.

[0032] The plasma processing device disclosed in the present invention solves the problem of inconsistent electromagnetic field strength at different radii in the prior art by arranging the excitation section of the coil to be longitudinally shaped. The excitation section is closer to the dielectric window than the return section, avoiding the return section from canceling the electromagnetic field generated by the excitation section, thereby greatly improving the utilization efficiency of the radio frequency power supply. The present invention uses a rotary drive device to drive the coil or base to rotate during the process, which can further improve the distribution uniformity of the plasma above the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are included in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, explain and illustrate the principles of the present invention. The drawings are intended to illustrate the main features of the various embodiments in a schematic manner, but are not intended to depict every feature of the actual embodiment or the relative sizes of the depicted elements, and are not drawn to scale.

[0034] Figure 1 is a schematic cross-sectional view of a plasma chamber according to one embodiment.

[0035] Figures 1A to 1F Various embodiments of rotatable contactless couplers are shown.

[0036] Figures 2A to 2G Examples of coils of various shapes are shown.

[0037] Figure 3A and Figure 3B An isometric view and a top view of a rotatable coil are schematically shown, respectively.

[0038] Figure 4 A top view of yet another embodiment of a rotatable coil is schematically shown.

[0039] Figure 5 An embodiment of a plasma chamber with a curved dielectric window is shown.

[0040] Figure 6 is a block diagram of a process flow according to one embodiment.

[0041] Figure 7 A cross-sectional view of another process chamber embodiment is schematically shown. DETAILED DESCRIPTION

[0042] The following is a further detailed description of a plasma processing device proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer based on the following description. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings in this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the conditions for the implementation of the present invention. Therefore, they have no technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and purpose that can be achieved by the present invention.

[0043] As mentioned in the background art, the coil on the dielectric window at the top of the ICP plasma chamber is typically configured in a ring or spiral shape. The magnetic field generated by this circumferentially extended coil typically generates mutual induction between coil sections of different radii, resulting in uneven plasma distribution at different radii within the reaction chamber, which in turn leads to uneven substrate processing. To address this technical problem, the present invention configures the coil above the dielectric window as a double-layer structure, including an excitation segment layer near the dielectric window and a return segment layer located above the excitation segment layer. When an RF signal is applied to the coil structure, since the excitation segment layer is closer to the reaction chamber and the current directions of multiple excitation segments are the same, the electromagnetic signals induced by the multiple excitation segments in the reaction chamber are superimposed on each other, which can greatly improve the utilization efficiency of the RF signal. When the substrate is processed in the reaction chamber, by controlling the relative rotation of the coil and the substrate, a uniform plasma distribution can be generated on the substrate surface, thereby uniformly processing the substrate with plasma.

[0044] Figure 1 A schematic diagram of the structure of a plasma processing apparatus is shown, comprising a vacuum chamber 100 and a dielectric window 105 disposed at the top of the chamber. A coil 120 is disposed above the dielectric window. Unlike conventional planar spiral coils, the coil 120 of the present invention comprises an excitation segment layer adjacent to the dielectric window and a return segment layer located above the excitation segment layer. The excitation segment layer comprises at least two substantially parallel, longitudinally elongated strips of excitation segments 126. Two adjacent excitation segments are connected by a height connecting segment 130 and a return segment 132, ensuring that each excitation segment 126 has the same current direction. When an RF signal is applied to the coil 120, the electromagnetic signals induced within the reaction chamber by the multiple excitation segments 126 with the same current direction superimpose on each other, generating a longitudinally elongated electromagnetic field distribution.

[0045] In order to obtain a more uniform plasma distribution, the present invention is provided with a rotation drive mechanism to realize the relative rotation of the coil 120 and the base 115. Figure 1 As shown, a rotation drive device, such as motor 141, can be provided below the base to achieve rotational drive of the base. Alternatively, a rotation drive device can be provided on the coil, or both the base and the coil can be provided with a rotation mechanism. Because the coil needs to be connected to an RF power source, its rotation mechanism is relatively complex and will be described in detail later in conjunction with the accompanying drawings.

[0046] In order to generate a uniform plasma distribution above the substrate, the several excitation segments 126 of the coil 120 can be set as straight line segments parallel to each other. Of course, in other embodiments, the excitation segments 126 can also be set as curves with a roughly long strip shape. Preferably, the curvature of adjacent curved excitation segments is close.

[0047] According to the above description, when radio frequency signals with the same current direction are passed through multiple excitation segments, superimposed electromagnetic field distributions will be generated in the reaction chamber. The length of the electromagnetic field distribution can be determined by the length of the excitation segment, and the width can be determined by the distance between the excitation segments with the greatest spacing. Therefore, in order to ensure that the edge and center areas of the substrate can be uniformly plasma-treated, the length of the excitation segment 126 can be set to be greater than the diameter of the substrate 110. Furthermore, when the length of the excitation segment 126 is greater than the diameter of the dielectric window 105, a longer electromagnetic field distribution can be obtained. When the distance between the excitation segments with the greatest spacing is greater than the diameter of the substrate or even greater than the diameter of the dielectric window, the electromagnetic field formed by the coil 120 in the reaction chamber is in the shape of a longitudinal or square distribution that fully covers the substrate, so that the surface of the substrate can be more uniformly plasma-treated.

[0048] The electromagnetic field distribution in the reaction chamber is affected not only by the excitation section 126, but also by the return section 132. Since the current direction of the return section 132 is opposite to that of the excitation section 126, the electromagnetic field generated by the return section 132 in the reaction chamber will offset the electromagnetic field intensity generated by the excitation section 126 in the reaction chamber. In order to minimize the offsetting effect of the electromagnetic field, the present invention provides a height connection section 130 between the return section and the excitation section. The height connection section 130 is preferably provided in a vertical direction so that the return section 132 and the excitation section 126 are located in different planes. Optionally, when the length of the height connection section 130 is greater than 1 / 2 of the length of the excitation section 126, the offsetting effect of the electromagnetic field generated by the return section 132 and the excitation section 126 in the reaction chamber will be significantly reduced, thereby improving the energy utilization rate of the RF power supply and avoiding uneven plasma distribution caused by different offsetting effects of the return sections 132 at different positions. In other embodiments, the height connection section 130 may also be arranged in a non-vertical direction. As long as the height of the return section layer and the excitation section layer can be adjusted, the purpose of the present invention can be achieved.

[0049] When the coil 120 is powered, the electromagnetic field intensity excited directly below the excitation segment is stronger, and the electromagnetic field intensity between the two excitation segments is slightly weaker. Therefore, the electromagnetic field intensity below the coil 120 is not absolutely uniform. In order to ensure the uniformity of substrate processing, it is necessary to compensate by rotation. Rotation can be to drive the base to rotate or to drive the coil to rotate. The following will describe an embodiment of the coil rotation of the utility model with reference to the accompanying drawings. Different embodiments or their combinations can be used for different applications or to achieve different benefits. Depending on the results to be achieved, the different features disclosed herein can be used alone or in combination with other features as needed to balance the advantages with the needs and constraints.

[0050] Figure 1EFIG. 1 is a schematic cross-sectional view of a plasma chamber according to an embodiment, including a rotating coil 120. A vacuum chamber 100 includes a dielectric window 105 serving as a ceiling. A substrate 110 to be processed is placed on a susceptor 115 within the vacuum chamber 100. A plasma is ignited and sustained within the vacuum chamber 100 by applying RF energy to the rotatable coil 120 (the direction of rotation is indicated by the counterclockwise curved arrow, but clockwise rotation is possible with similar results). The coil 120 can be positioned directly on the dielectric window or spaced apart from the window. In this example, the coil 120 includes a horizontal excitation segment 126 parallel to the window and a plurality of vertically oriented height connection segments 130. One or more of the height connection segments 130 are physically and electrically connected to a spindle 133. Rotation of the coil 120 is effected by coupling a motor 139 (shown by a dashed line) to the spindle 133. RF power is applied to the coil 120 from an RF power supply 140 through an input port (sometimes referred to as a hot-side connector), which in this embodiment is provided by a non-contact coupler 135. Incidentally, because RF energy is transferred through a contactless coupler without ohmic contact between the signal input and output, the contactless coupler can be considered a form of transformer, although the signal passing through it is not altered.

[0051] exist Figure 1E In the embodiment of the present invention, the contactless coupler 135 is formed as a DC disconnect / RF short circuit, that is, the contactless coupler is composed of two contact points separated from each other in space, which are not in direct physical or electrical contact, wherein the two contact points can rotate relative to each other, for example, the outer contact point is fixed and the inner contact point is rotatable. Figure 1E In the embodiment shown, this is achieved by manufacturing the contactless coupler to have internal contacts 134 (at Figure 1E Conductive ring in the figure) and external contact points (in the Figure 1E 136). In this embodiment, the outer contact point 136 is fixed, while the inner contact point 134 is rotatable. As shown in the top view framed by the dotted line, the inner contact point 134 (conductive ring) and the outer contact point 136 (larger conductive ring) are coaxial with a space 137 in between, so that they do not physically or electrically contact and allow relative rotation. On the other hand, the inner contact point 134 is electrically connected to the main shaft 133, which is coaxial with the inner contact point 134 and the outer contact point 136. In this embodiment, the inner contact point 134 is an inner conductive ring and the outer contact point 136 is an outer conductive ring. Here, the outer conductive ring 136 is fixed, while the inner conductive ring 134 rotates with the shaft 133.

[0052] pass Figure 1EIn the particular arrangement shown in FIG, the inner conductive ring 134 and the outer conductive ring 136 form a capacitor, so that RF energy can pass through the space 137 by capacitive coupling, i.e., forming an RF short circuit. Conversely, DC current cannot flow from the outer conductive ring 136 to the inner conductive ring 134, thus forming a DC short circuit. The space 137 outlined in dashed lines is occupied only by air. Alternatively, as outlined in dashed lines, the space 137 can be filled with a dielectric material 138, such as a ceramic ring, Rings, etc., are provided to increase the dielectric constant of the capacitor formed by the inner and outer rings, thereby improving the transmission of RF energy. The dielectric material can completely or partially fill space 137. In one example, dielectric material 138 is placed in space 137 so that this arrangement also serves as a rotational bearing for spindle 133. Alternatively, a separate rotational bearing 132 can be installed on shaft 133 to ensure stable axial rotation of motor 139.

[0053] Figures 1A-1D Various embodiments of contactless couplers are shown in which an inner contact and an outer contact form one or more arcs rather than a complete circle. Figure 1A In FIG, the inner contact point 134 forms an arc, which is a semicircle here, but can cover an angle smaller or larger than a semicircle (180 degrees). Figure 1B In the embodiment, the inner contact point 134 forms two arcs, and in Figure 1C The inner and outer contact points 136 form two arcs. It can be seen that the inner and outer contact points can form one or more arc-shaped contact points. Figure 1D The inner contact point 134 is shown in the form of a plurality of arcs attached to the support cylinder 131 to enhance the mechanical stability of the inner contact point 134. The support cylinder can be made of an insulating material and can be fixed to the main shaft 133 or serve as a rotation bearing on the main shaft 133.

[0054] One or more high-level connecting sections 130 may be used to connect the coil 120 to ground to complete the RF circuit. Figure 1E In the embodiment of the present invention, this is also achieved by a non-contact coupler having an inner ground ring 144 and an outer ground ring 146. The inner ground ring 144 rotates with the coil 120, while the outer ground ring 146 is fixed. Similarly, the inner ground ring 144 does not contact the outer ground ring 146, and the space between the inner ground ring 144 and the outer ground ring 146 can be filled with air or a ring made of a dielectric material (such as ceramic, etc.) occupied.

[0055] In the disclosed embodiments, because RF energy is transferred to the coil via capacitive coupling, problems associated with conventional contact points are avoided. For example, particles are not generated, and RF energy is smoothly transferred via capacitive coupling, resulting in no spikes, arcing, or unstable impedance. Consequently, a stable plasma can be maintained within the vacuum chamber. In other embodiments, brushes or other methods can be used to achieve simultaneous electrical connection of the coil 120 while it rotates.

[0056] according to Figure 1E The disclosed embodiment provides a schematic diagram of a plasma processing apparatus having a base supporting a substrate in a vacuum chamber; a dielectric window provided at the ceiling of the vacuum chamber, the dielectric window being located in a horizontal plane; a rotating coil provided above the dielectric window, the rotating coil comprising: a main shaft rotating around an axis, an input port, and a ground port; wherein the input port and the ground port are both formed by non-contact capacitive coupling connectors. Figure 1E In some embodiments, a contactless capacitive coupling connector is formed by a receiving ring electrically connected to a spindle and a transmitting ring coupled to an RF power source, with RF energy flowing through an insulating space between the transmitting and receiving rings via capacitive coupling. In some embodiments, the insulating space is occupied by air, while in other embodiments, the insulating space is occupied by a dielectric material (e.g., a dielectric ring).

[0057] exist Figure 1E In an embodiment, the rotating coil rotates around a main axis, the main axis is connected to a receiving ring coaxial with the main axis and rotating with the main axis, the receiving ring being made of a conductive material; a transmitting ring is made of a conductive material, positioned coaxially with the receiving ring, and an insulating gap is defined between the input ring and the receiving ring, the transmitting ring is coupled to an RF power supply, and the RF signal is capacitively coupled between the input ring and the receiving ring through the insulating gap; the coil also includes an excitation segment connected to the main axis and parallel to the ceiling plane, the excitation segment radiates the RF energy received from the main axis; and a grounding port is connected to the radiating coil, the grounding port includes a rotating ring connected to the radiating coil and rotating coaxially with the main axis, and a fixed ring coaxial with the rotating ring, a second insulating space is defined between the rotating ring and the fixed ring, and the fixed ring is connected to the ground potential.

[0058] Figure 1F A schematic diagram of the electrical connection of the coil in another embodiment is shown. Figure 1E The middle excitation section receives RF energy from the main axis. Figure 1F There is no obvious main axis structure, and the input (I In) and output (I Out) of RF energy are both carried out from the edge area of the coil. In this embodiment, the height connection section (not shown in the figure) connected to the excitation section is fixedly connected to the inner conductive ring 134, and the outer conductive ring 136 and the inner conductive ring 134 can rotate relative to each other; similarly, a height connection section 130 can be used to ground the coil 120 to complete the RF circuit. Figure 1FIn the embodiment of FIG. 1 , this is also achieved by a contactless coupler having an inner grounding ring 144 and an outer grounding ring 146. The inner grounding ring 144 rotates with the coil 120, while the outer grounding ring 146 is fixed. Figure 1F The deformation arrangement of the inner conductive ring 134 and the outer conductive ring 136 and the inner grounding ring 144 and the outer grounding ring 146 can be referred to Figures 1A-1D , part of it is set to arc shape, which will not be described here.

[0059] In the context of this disclosure, the term "ground potential" refers to any common reference voltage potential of a plasma chamber, which may or may not be earth (zero) potential.

[0060] The coil 120 may be formed in various shapes. Figures 2A-2F Embodiments of coils of different shapes are schematically illustrated, wherein only elements relevant to the flow of RF energy are shown, while mechanical and / or structural details are omitted for clarity. Figures 2A-2D In an embodiment, the coil 120 includes at least two excitation segments 126 arranged parallel to the dielectric window and parallel to each other, and a high-level connector segment couples the coil to the RF power source. The high-level connector segment may include a vertical connector, generally perpendicular to the excitation segment layer and oriented away from the excitation segment layer, that is, away from the dielectric window plane. The high-level connector segment may also include a return segment 132, which is located in a plane parallel to the excitation segment layer but further away from the dielectric window. With this arrangement, the dielectric window is located at a relatively uniform distance from the magnetic field generated by the large-scale induction coil. Therefore, the rotating induction coil uniformly ignites and maintains the plasma within the vacuum chamber. In addition, any return segment is placed in a plane far enough away from the dielectric window to avoid interfering with the plasma maintained by the coil. Therefore, only the excitation segments close to the window can effectively maintain the plasma within the vacuum chamber. These excitation segments can be referred to as drive coils, while the other conductors serve as various connectors.

[0061] Figure 2AA coil layout is shown, wherein the coil is composed of a plurality of parallel, straight (linear) excitation segments 126. These excitation segments are composed of straight conductors and lie in a plane parallel to the dielectric window plane, forming an excitation segment layer. Each excitation segment 126 is connected at one end to a vertical height connection segment, and a plurality of return segments 132, parallel to each other and located in a plane parallel to the dielectric window plane and at a distance greater than the coil plane, are connected at one end to the vertical height connection segment 130. This connection connects all excitation segments 126 in series, resulting in a single input terminal I in and a single ground terminal I out. The excitation segment layer is positioned sufficiently close to the dielectric window plane that only the excitation segments 126 of the coil can effectively generate a plasma within the chamber. These excitation segments can be identified as drive coils, while the remaining portions of the coil serve as various connectors. The return segments 132 are positioned sufficiently far from the window plane that their effect on the plasma is negligible or non-existent. Furthermore, in this embodiment, all straight excitation segments 126 are of the same length, preferably longer than the diameter of the substrate to be processed within the plasma chamber.

[0062] Another embodiment of the rotatable coil is as follows Figure 2B As shown, multiple coils are connected in series, and the straight excitation segments 126 have different lengths. Figure 2B As shown, the straight excitation segments 126 are located in a plane parallel to the dielectric window plane and are connected in series with the RF power supply via a vertical height connecting segment 130 and a return segment 132. This configuration can be used to control the plasma density at different radii within the vacuum chamber. In this particular embodiment, at least one excitation segment 126 spans the entire diameter of the dielectric window 105 and may actually extend beyond the diameter of the window 105. In contrast, the length of the remaining straight excitation segments 126 is shorter than the central excitation segment, with the length of each excitation segment gradually decreasing to be shorter than the radius of the substrate. In the embodiment shown, the excitation segments are arranged in a manner that produces higher radiation in the peripheral area of the substrate, thereby increasing the plasma density at the periphery. This configuration is beneficial when the structure of the vacuum chamber naturally results in lower plasma density at the periphery, so that higher RF energy at the periphery can balance the uniformity of the plasma.

[0063] exist Figure 2B In FIG. 1 , each exciting segment 126, together with the height connecting segment 130 and the return segment 132 connected thereto, forms a rectangular induction coil, as shown in FIG. Figure 2BAs shown in the boxed portion of the diagram, each induction coil has a different size. Therefore, the plasma generated by the induction coils in each loop corresponds to a different region of the plasma. The plasma concentration generated by the stacking of multiple horizontal induction coils achieves an optimal distribution. The size and position of each induction coil can be configured for each plasma chamber to achieve the optimal plasma distribution. For example, different vacuum chambers and different plasma processes may require different plasma density distributions, and the desired plasma distribution can be achieved by adjusting the size and position of each induction coil.

[0064] Figure 2C An embodiment of an RF coil is schematically illustrated, comprising a set of rectangular induction coils 126a-126c (see the boxed portion) electrically connected and mechanically fixed together for common rotation about a main axis 133. By connecting multiple coils in parallel, the inductance can be significantly reduced and the drive current can be increased. The center coil 126a, covering the center of the dielectric window 105, has the largest dimension, i.e., length, while the coils 126b and 126c, covering the edge regions, can be shorter. As long as both ends of each drive coil extend beyond the dielectric window 105, the uniformity of the underlying plasma can be maintained. In alternative embodiments, the multiple parallel excitation segments can be of equal length and mechanically fixed together for rotation, without a distinct main axis structure.

[0065] exist Figure 2C In the embodiment shown, the excitation segments 126 are connected in parallel so that each rectangular coil 126a-126c is independently connected to the RF input and ground. Figure 2C As shown by the arrows in , the current in each excitation segment 126 flows in the same direction. Figure 2C In the specific embodiment shown, the input terminals of all induction coils are arranged on one side, and all ground terminals are arranged on the other side. When multiple excitation segments 126 are connected in parallel, the parallel excitation segments can be connected to different internal contact points 134 through height connection segments of different heights. The internal contact points can be ring-shaped or arc-shaped. In other embodiments, multiple parallel excitation segments can also be connected to the same ring-shaped or arc-shaped internal contact point, such as Figure 2D As described above, in this embodiment, the lengths of the excitation segments or height connection segments at different positions to the inner conductive ring 134 are slightly different to ensure good electrical connection with the inner conductive ring. Figure 2D for Figure 2C The electrical connection diagram of the structure shown is as follows. Figure 1F Similar, no further description is given here.

[0066] exist Figures 2A-2DIn the embodiment shown, the excitation segments 126 are located in the same plane and are parallel to each other. The distance between the excitation segments is configured to ensure that the electromagnetic fields generated by two adjacent excitation segments overlap. With this arrangement with the electromagnetic fields of two adjacent excitation segments overlapping, the uniformity of the plasma can be enhanced by the relative rotation between the coil and the substrate. Figure 1E and 1F As shown, relative rotation can be achieved by rotating coil 120. Alternatively, relative rotation can be achieved by rotating the substrate, for example, by rotating a support (eg, a chuck) for the substrate via optional motor 141.

[0067] The above embodiments disclose an arrangement in which the excitation segments are located in the same plane. Figure 2E Disclosed is a schematic diagram of an excitation segment layer located in different planes. Research has found that in certain applications, the electromagnetic field intensity generated by the coil 120 tends to be stronger in the central region than in the edge region. By setting the excitation segment to include a central excitation segment 126m and edge excitation segments 126e located on both sides of the central excitation segment, and setting the distance from the central excitation segment 126m to the dielectric window to be greater than the distance from the edge excitation segment 126e to the dielectric window, the electromagnetic field intensity generated by the central excitation segment is appropriately weakened, achieving overall uniformity in the central and edge regions. The height difference between the central excitation segment 126m and the edge excitation segment 126e and the dielectric window can be set as needed. Based on the same principle, Figure 2F Another variant embodiment provides a method for achieving uniformity in both the central and edge regions by configuring the return segment 132 as a central return segment 132m and an edge return segment 132e. By setting the distance between the central return segment 132m and the dielectric window to be shorter than the distance between the edge return segment 132e and the dielectric window, the electromagnetic field offset of the central return segment 132m against the central return segment 126m is appropriately enhanced, thereby achieving uniformity in both the central and edge regions. In other embodiments, the excitation segment 126 and the return segment can be configured as a central segment and a return segment located adjacent to each other, which will not be further described here.

[0068] Figure 2G Another embodiment of a coil is shown. In this embodiment, the excitation segment and the return segment are located in the same plane, and the current flows in alternating directions in each adjacent excitation segment and return segment. Although this embodiment will lose some RF power efficiency, due to the electromagnetic field offsetting and superposition effect of the excitation segment and the return segment, a better uniform electromagnetic field distribution can be obtained.

[0069] Figure 3A and Figure 3B The rotatable coil 120 is schematically shown in an isometric view and a top view, respectively. In this embodiment, the coil is composed of a plurality of horizontal drive coils connected in parallel, with different positions, orientations and lengths. Figure 3A and Figure 3BThe arrangement shown is configured to increase the plasma concentration as the radius increases from the axis. The plasma density within the chamber can be balanced by rotating the coil.

[0070] Figure 4 A top view of another rotatable coil 120 is schematically shown. Figure 4 The coil in FIG. 1 is composed of a plurality of curvilinear excitation segments 126 arranged in a rotationally symmetrical pattern and connected at one end to a main axis 133. In this embodiment, each excitation segment 126 has a curved branch 127 extending from it. Figure 4 In the embodiment, the coil has three main excitation segments 126, each with a branch 127, but the number of main excitation segments and branches can be designed based on the desired plasma distribution and density. As with other embodiments, RF energy is connected to the main shaft 133 via capacitive coupling, and ground is coupled through the ends of the excitation segments 126 and branches 127. In this regard, although most of the description suggests that both the RF access side and the ground side are connected to the coil via capacitive coupling, it is also possible to connect the RF access side via capacitive coupling and the ground via ohmic contact. For example, the RF access side can be connected via capacitive coupling using any of the non-contact couplers disclosed herein, while the ground can be connected via ohmic contact using brushes.

[0071] Plasma inherently seeks pressure equilibrium within the vacuum chamber, so the natural distribution of plasma is spherical. In addition, due to the crystal growth of silicon, silicon substrates are usually circular flat plates. However, glass substrates are usually rectangular. With this in mind, designers usually design plasma chambers with circular sidewalls so that the plasma within the vacuum chamber "sees" circular symmetry. Since the substrate is flat, the base supporting the substrate is also flat, resulting in a flat floor design. For ease of manufacturing and to reduce costs, dielectric ceilings are also made flat, such as Figure 1 However, allowing the plasma to be "squeezed" between the flat substrate and the ceiling results in an increase in density at the center of the plasma. To address this issue, some chambers use dome-shaped ceilings, such as Figure 5 shown.

[0072] Figure 5An embodiment of a plasma chamber having a dome-shaped curved dielectric window is shown. The plasma chamber has a sidewall 500, which may be cylindrical. A base 510 is located on the floor of the chamber and supports one or more substrates 515. A curved dielectric window 505 is located above the sidewall to complete the vacuum chamber in which the plasma 501 is ignited. In this embodiment, the dielectric window is shaped into a dome or dome shape. A curved rotatable coil 525 is located above the dielectric window 505, and the excitation segments are generally arranged to follow the shape of the dielectric window as parallel curved strips. The coil includes a main shaft 533 and is connected to a motor 539. RF energy is transferred from an RF power supply 540 through a matching circuit 541 and then capacitively coupled to the coil 525 via a non-contact coupler 535. Note that the matching circuit 541 can be used with any of the embodiments disclosed herein.

[0073] exist Figure 5 In the embodiments of, and in any other embodiments disclosed herein, there are multiple ways to construct the contactless coupler. Figure 5 The boxed portion on the right shows two examples that can be used in any other embodiment. The boxed portion on the right shows a non-contact coupler 535 having an inner ring 534 physically connected to the main shaft 533 for rotation therewith. A dielectric ring 538 is provided above the inner ring 534, and an outer ring 536 is provided above the dielectric ring. The inner dielectric ring rotates with the main shaft 533, while the outer ring 536 is fixed. The outer ring 536 is connected to an RF power source 540 via a matching circuit 541 and capacitively couples RF energy to the inner ring via the dielectric ring 538. In this way, the non-contact coupler 535 also serves as a rotational bearing for the main shaft 533.

[0074] Figure 5 The boxed portion on the left illustrates another embodiment of a contactless coupler. This embodiment simplifies the contactless coupler by eliminating the inner ring. Here, the spindle 533 itself serves as the inner ring, so a dielectric ring 538 is provided above the spindle 533, also serving as a rotary bearing. An outer ring 536 is provided above the dielectric ring 538 and capacitively couples RF energy directly to the spindle 533.

[0075] Figure 5 The coil 525 shown in FIG. 5 can be grounded using any conventional rotary connector, such as a brush, but Figure 5 Coil 535 is shown connected to ground via another contactless coupler 535g. The contactless coupler consists of an inner ring 544 that rotates with coil 525 and a fixed outer ring 546. The outer ring 546 is ohmically connected to ground and is coaxial with the inner ring 544 to form a capacitive coupling of RF energy.

[0076] It can be understood from the present disclosure that by rotating the induction coil, the plasma concentration below the dielectric window has the same concentration at different azimuth angles. By selecting an appropriate horizontal drive coil mode, a uniform plasma concentration can be achieved in the radial direction. Ultimately, the plasma concentration uniformity within the reaction chamber is significantly higher than that of conventional technologies using multiple fixed loop coils or spiral coils. RF energy is coupled to the coil via capacitive coupling, resulting in uniform energy transfer, thereby maintaining a stable plasma. In addition, when a contactless coupler is used, the generation of particles is avoided and the service life of the rotatable coil is extended.

[0077] The present disclosure also discloses a method of operating a plasma chamber, such as Figure 6 As shown. The process begins at step 600 with the insertion of a substrate into the chamber. At step 605, process gas is injected into the chamber and at step 610, the coil motor is activated to rotate the coil. At step 615, the RF power supply is activated to capacitively couple RF energy to the coil to ignite and maintain a plasma within the chamber. When the processing time is complete, the RF energy is turned off at step 620 to extinguish the plasma and any remaining exhaust gases are evacuated from the chamber at step 625. The processed wafer is removed at step 630 and the process is repeated for the next substrate. Please note that the order of the process steps described herein is not mandatory and the order of certain steps can be changed or additional steps can be added. For example, a step can be added to apply a chuck voltage to the chuck to clamp the substrate. In addition, although a step of evacuating the chamber is mentioned, the chamber is actually evacuated throughout the process of injecting process gas into the chamber to remove the exhaust gases.

[0078] Figure 7 Another embodiment of a processing chamber having a rotatable coil is shown. Figure 7 In the embodiment with Figure 5 Similar elements are identified with the same reference numerals and are not described again here. Figure 7 The embodiment differs from the other embodiments disclosed herein in that the upper portion of the vacuum chamber includes a dielectric window 706, which forms a portion of or an extension of the sidewall 500. The dielectric window 706 may be cylindrical and may terminate at a ceiling 707. The ceiling 707 may be a flat circular disk, which may be made of a dielectric material, as shown in dashed lines. If the ceiling 707 is made of a dielectric material, it can be made integrally with the cylindrical dielectric window 706. The coil 725 is made to extend downwardly so as to rotate around the dielectric window 706. The coil 725 is connected to the shaft 533 as shown and is rotated by the motor 539, as in the other embodiments disclosed herein.

[0079] Figure 7Another feature that can be implemented in any of the other embodiments shown herein is the use of a belt drive system to impart rotation to the coil. This can be used to prevent any RF energy from flowing into the motor 739. In this arrangement, the motor can be mounted separately and remotely, and the belt 731 can be used to impart rotational motion to the shaft 733.

[0080] Figure 7 The boxed portion in FIG. 7 illustrates another feature that can be implemented in any of the embodiments disclosed herein, wherein the inner ring 734 and outer ring 736 are configured as the inner and outer rings of a ball bearing, with the dielectric isolator formed by balls 738 made of a dielectric material. The balls can also be seated in a cage made of a dielectric material. In this case, while reference is generally made to the balls of a ball bearing, it should be understood that this reference includes other types of rollers commonly used in bearings, such as cylindrical rollers. Furthermore, the bearing may be sealed, with a dielectric fluid provided between the inner and outer rings.

[0081] Thus, through the present disclosure, a plasma processing chamber is provided, comprising: a vacuum chamber; a substrate support located on a floor of the vacuum chamber; a dielectric window located above the vacuum chamber; a coil disposed about the dielectric window, the coil being connected to a rotatable shaft; a motor connected to the rotatable shaft; an RF power supply; and a contactless coupler for capacitively coupling RF energy transmitted by the RF power supply to the coil. The dielectric window may form a ceiling of the vacuum chamber, and the coil may be located above the ceiling. Alternatively, the ceiling may form a flat disk, and the coil may include a plurality of excitation segments located in a plane parallel to the ceiling. Alternatively, the ceiling may form a dome, and the coil may include a plurality of curved excitation segments. Alternatively, the dielectric window may form a cylindrical extension of a sidewall of the vacuum chamber, and the coil may extend downwardly about the dielectric window.

[0082] The disclosure includes a contactless coupler comprising a capacitor having an input contact connected to an RF power source and an output contact connected to a coil, and a dielectric isolator may be positioned between the input contact and the output contact. In an embodiment, the input contact, the output contact, and the dielectric material comprise concentric rings. Embodiments include where the output contact is connected to or forms part of a rotatable shaft. Thus, the input contact is fixed and the output contact rotates with the shaft. Additionally, the input contact, the output contact, and the dielectric isolator may form a rotating bearing that supports the shaft. In an embodiment, the contactless coupler comprises a bearing having a conductive inner ring, a conductive outer ring, and a roller made of a dielectric material.

[0083] In one embodiment, the plasma chamber includes a ground coupler coupling the coil to the ground potential of the RF power supply. The ground coupler can provide a DC disconnect / RF short circuit. The coil can include multiple excitation segments connected in series or in parallel. The coil can include multiple straight excitation segments, forming a plurality of rectangular coils. In one embodiment, at least two of the plurality of rectangular coils have different lengths. The motor can be directly connected to the rotatable shaft or connected to the rotatable shaft via a belt drive.

[0084] The disclosure also includes a method for processing a substrate in a plasma chamber, comprising: inserting a substrate into the plasma chamber; injecting a process gas into the plasma chamber; activating a coil motor to rotate an induction coil; activating an RF power supply; capacitively coupling RF energy generated by the RF power supply to the coil to ignite and maintain a plasma in the plasma chamber and process the substrate; ceasing coupling RF energy to the coil when a processing time is completed to extinguish the plasma; extracting any remaining exhaust gas from the plasma chamber; and removing the substrate from the plasma chamber.

[0085] It should be understood that the processes and techniques described herein are not inherently related to any particular apparatus and may be implemented using any suitable combination of components. Furthermore, various types of general-purpose apparatus may be used in accordance with the teachings herein. The present invention has been described with reference to specific examples, which are intended in all respects to be illustrative rather than restrictive. Those skilled in the art will appreciate that many different combinations will be suitable for practicing the present invention.

[0086] In addition, other embodiments of the present invention will be apparent to those skilled in the art, who will understand them through consideration of the specification and practice of the present invention disclosed herein. The various aspects and / or components of the described embodiments may be used alone or in any combination. The true scope and spirit of the present invention are defined by the following claims.

Claims

1. A plasma processing device, characterized in that include: vacuum chamber; a base, located in the vacuum chamber and used to support the substrate during the process; a dielectric window, located at the top of the vacuum chamber and arranged opposite to the base; a coil, at least partially located above the dielectric window, comprising at least two elongated excitation segments; A radio frequency power supply applies a radio frequency signal to the coil so that the current directions of the two excitation segments are in the same direction; The rotary drive device is used to drive the coil and / or the base to rotate, so that the coil and the base can rotate relative to each other during the process.

2. The plasma processing apparatus according to claim 1, wherein The electromagnetic fields generated by the two excitation segments are superimposed on each other, generating a longitudinal electromagnetic field distribution above the substrate.

3. The plasma processing apparatus according to claim 1, wherein The multiple excitation segments of the coil are connected in series or in parallel.

4. The plasma processing apparatus according to claim 1, wherein The two excitation segments are arranged parallel to each other.

5. The plasma processing apparatus according to claim 1, wherein The length of the excitation segment is greater than the diameter of the substrate.

6. The plasma processing apparatus according to claim 1, wherein: The length of the excitation segment is greater than the diameter of the dielectric window.

7. The plasma processing apparatus according to claim 1, wherein The coil includes at least two excitation segments and a return segment connecting two adjacent excitation segments, and the return segment and the excitation segment are located in different planes.

8. The plasma processing apparatus according to claim 7, wherein: The coil further includes a height connection section connecting the excitation section and the return section, wherein the height connection section enables a distance from the return section to the dielectric window to be greater than a distance from the excitation section to the dielectric window.

9. The plasma processing apparatus according to claim 8, wherein The length of the height connection section is greater than 1 / 2 of the length of the excitation section.

10. The plasma processing apparatus according to claim 1, wherein The excitation segment includes a central excitation segment and edge excitation segments located on both sides of the central excitation segment. The distance between the central excitation segment and the dielectric window is greater than the distance between the edge excitation segments and the dielectric window.

11. The plasma processing apparatus according to claim 7, wherein: The return section includes a central return section and edge return sections located on both sides of the central return section. The distance between the central return section and the dielectric window is smaller than the distance between the edge return sections and the dielectric window.

12. The plasma processing apparatus according to claim 1, wherein The RF power supply supplies RF signals to the coil via a non-contact coupler. The non-contact coupler includes a transmitting end and a receiving end. The receiving end is electrically connected to the input end of the coil, and the transmitting end is electrically connected to the RF power supply.

13. The plasma processing apparatus according to claim 12, wherein: The receiving end rotates synchronously with the coil, and the receiving end rotates relative to the transmitting end.

14. The plasma processing apparatus according to claim 13, wherein: At least one of the receiving end and the transmitting end is a ring conductor.

15. The plasma processing apparatus according to claim 1, wherein The radio frequency power supply supplies a radio frequency signal to the coil through a brush.

16. The plasma processing apparatus according to claim 1, wherein The lengths of the excitation segments are equal or unequal.

17. The plasma processing apparatus according to claim 1, wherein The coil is connected to a rotating shaft, and the rotating driving device drives the rotating shaft to drive the coil to rotate.

18. The plasma processing apparatus according to claim 1, wherein The rotation driving device is a motor.

19. The plasma processing apparatus according to claim 1, wherein The dielectric window is dome-shaped, and the excitation segment of the coil is a curved segment.

20. The plasma processing apparatus according to claim 1, wherein The dielectric window is cylindrical.

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