Method of tuning plasma profile

Abstract

Apparatus and methods for controlling plasma profiles in PVD deposition processes are disclosed. Some embodiments utilize an EM coil placed above a target during deposition to control the plasma profile.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to apparatuses and methods for controlling a plasma. More particularly, embodiments of the present disclosure relate to apparatuses and methods for controlling a plasma profile in a PVD deposition process using an electromagnet. Background Art

[0002] Sputtering, or physical vapor deposition (PVD), is used to deposit metals and related materials in the manufacture of semiconductor integrated circuits. The use of sputtering has also been extended to depositing metal layers on the sidewalls of high aspect ratio holes such as vias or other vertical interconnect structures, as well as in the manufacture of extreme ultraviolet (EUV) mask blanks.

[0003] In a plasma enhanced substrate processing system such as a physical vapor deposition (PVD) chamber, high power density PVD sputtering with high magnetic fields and high DC power can generate high energy at the sputtering target and cause a significant increase in the surface temperature of the sputtering target. The sputtering target is cooled by contacting the target backplate with a cooling fluid. In plasma sputtering, which is commonly practiced commercially, a target of the material to be sputter deposited is sealed into a vacuum chamber containing the wafers to be coated. Argon gas is introduced into the chamber. In the sputtering process, the sputtering target is bombarded with high energy ions such as a plasma, causing the material to be displaced from the target and deposited in the form of a film on a substrate placed inside the chamber.

[0004] Therefore, as device dimensions shrink, controlling the deposition process is crucial. In addition, controlling the plasma to be uniform across the entire sputtering target to improve corrosion characteristics and to evenly wear the target material over time, and to control the life of the target.

[0005] Plasma sputtering can be accomplished using DC sputtering or RF sputtering. Plasma sputtering typically includes a magnetron located on the backside of the sputtering target, the magnetron including at least two magnets of opposite polarities that are magnetically coupled on its backside via a magnetic yoke, thereby projecting a magnetic field into the processing space to increase the density of the plasma and enhance the sputtering rate from the front side of the target. The magnets used in the magnetron are typically closed-loop for DC sputtering and open-loop for RF sputtering.

[0006] Current hardware solutions for plasma control in PVD processing rely on such solid state magnets having various configurations that rotate behind the target. Adjusting or modifying the magnet configuration requires a significant amount of hardware work and chamber downtime. Therefore, there is a need for a hardware solution that allows software control of the magnetic field and eliminates the need for new magnet designs.

[0007] The thickness tolerances of many optical multilayer coating stacks can be very stringent and require precise deposition control and monitoring. In addition to the common problems associated with process control and layer thickness monitoring (especially for coatings with small error tolerances), larger substrates also add another difficulty because the non-uniformity of the coating thickness may exceed the designed error tolerance.

[0008] Therefore, there is also a need for methods and equipment for controlling the plasma profile in the PVD deposition process to control the deposition rate, film properties, and other process improvements. SUMMARY OF THE INVENTION

[0009] One or more embodiments of the present disclosure are directed to a plasma cathode assembly that includes a cathode housing having a top, sidewalls, and a backplate that enclose an internal volume having a central axis. The backplate is configured to support a target during a sputtering process. A first EM coil is located inside the internal volume of the cathode housing. The first EM coil has a first inner diameter and a first outer diameter that define a first coil width, and a first bottom surface and a first top surface that define a first coil thickness. A second EM coil is located inside the internal volume of the cathode housing. The second EM coil has a second inner diameter and a second outer diameter that define a second coil width, and a second bottom surface and a second top surface that define a second coil thickness. The first EM coil is within the second inner diameter of the second EM coil.

[0010] Additional embodiments of the present disclosure relate to a plasma processing chamber that includes a chamber body having a bottom, sidewalls, and a top plate that enclose a processing volume. A substrate holder is located within the processing volume. A plasma cathode assembly is located above the substrate holder. The plasma cathode assembly includes a cathode housing having a top, sidewalls, and a backplate that enclose an internal volume having a central axis. The backplate is configured to support a target. A first EM coil is located inside the internal volume of the cathode housing. The first EM coil has a first inner diameter and a first outer diameter that define a first coil width. A second EM coil is located inside the internal volume of the cathode housing. The second EM coil has a second inner diameter and a second outer diameter that define a second coil width. The first EM coil is within the second inner diameter of the second EM coil.

[0011] Other embodiments of the present disclosure are directed to a method of adjusting a plasma profile. The method includes one or more of the following: controlling the spacing of EM coils within a plasma cathode assembly; modulating the direction or amount of current flowing through one or more EM coils within a plasma cathode assembly; or controlling the position of the EM coils within a plasma cathode assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Reference may be made to a number of embodiments to more particularly illustrate the present disclosure as briefly summarized above, and to more fully understand the above features of the present disclosure. The accompanying drawings illustrate some of the embodiments. However, it should be noted that the accompanying drawings only illustrate typical embodiments of the present disclosure and should not be considered as limiting the scope of the present disclosure, since the present disclosure may permit other equivalent embodiments.

[0013] FIG. 1 is a cross-sectional side view of a PVD deposition chamber according to one or more embodiments of the present disclosure;

[0014] FIG. 2 is a cross-sectional perspective view of a plasma cathode assembly according to one or more embodiments of the present disclosure;

[0015] FIGS. 3A-3C illustrate the change in the magnetic field caused by the rotation of the bar magnet;

[0016] FIGS. 4A-4B illustrate the change in the magnetic field caused by the permanent magnet near the central axis; and

[0017] FIG. 5 illustrates a cross-sectional view of a plasma cathode assembly according to one or more embodiments of the present disclosure.

[0018] In the accompanying drawings, like components and / or features may have the same reference numerals. Furthermore, for each of the same type of components, they may be distinguished by the letter after the reference numeral, and this letter distinguishes the similar components. If only the first reference numeral is used in the specification, the description thereof may apply to any of the similar components having the same first reference numeral, regardless of the suffix letter. Embodiments

[0019] Before describing several exemplary embodiments of the present disclosure, it should be understood that the present disclosure is not limited to the details of the structures or processing steps set forth in the following description. The present disclosure is capable of other embodiments and of being practiced or carried out in various ways.

[0020] As used in this specification and the appended claims, the term "substrate" refers to the surface or a portion of the surface on which processing is performed. Those skilled in the art will also understand that, unless the context clearly indicates otherwise, a reference to a substrate may also refer only to a portion of the substrate. Additionally, a reference to depositing on a substrate may refer to both a bare substrate and a substrate having one or more films or features deposited or formed thereon.

[0021] As used herein, the term "substrate" refers to any substrate or the surface of a material formed on a substrate on which film processing is performed during the manufacturing process. For example, the substrate surfaces on which processing can be performed include materials such as silicon, silicon oxide, strained silicon, silicon-on-insulator (SOI), carbon-doped silicon oxide, amorphous silicon, doped silicon, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials, depending on the application. Substrates include, but are not limited to, semiconductor wafers. The substrate can be exposed to a pretreatment process to polish, etch, reduce, oxidize, hydroxylate, anneal, UV cure, electron beam cure, and / or bake the substrate surface. In addition to performing film processing directly on the surface of the substrate itself, in the present disclosure, any film processing step disclosed can also be performed on an underlying layer formed on the substrate, as described in more detail below, and the term "substrate surface" is intended to include the underlying layer indicated by the context. Thus, for example, in the case where a film / layer or a partial film / layer has been deposited on the substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0022] The term "horizontal" as used herein is defined as a plane parallel to the plane or surface of the mask blank, regardless of its orientation. The term "vertical" refers to a direction perpendicular to the horizontal direction defined above. Terms such as "above", "below", "bottom", "top", "side" (as in "sidewall"), "higher", "lower", "above", "above", and "below", as shown in the figure, are defined relative to the horizontal plane.

[0023] Embodiments of the present disclosure relate to a plasma cathode assembly that includes a plurality of electromagnetic (EM) coils behind a target material. The positions of the EM coils should be such that one coil is located within another coil. Other embodiments of the present disclosure relate to a method of using the plasma cathode assembly disclosed herein to control the plasma field in a PVD deposition chamber. In some embodiments, the plasma density and / or the plasma position are controlled.

[0024] Some embodiments of the present disclosure advantageously provide a rapid (e.g., immediate) adjustment of the plasma distribution in a plasma-based deposition process (e.g., physical vapor deposition (PVD)). Some embodiments of the present disclosure advantageously provide a significantly reduced development time for new PVD processes. Similarly, some embodiments of the present disclosure advantageously provide a deposition process with a controlled deposition rate.

[0025] Some embodiments of the present disclosure advantageously provide for full surface corrosion of the target material. Some embodiments of the present disclosure advantageously provide the ability to manipulate film properties during a deposition process. In some embodiments, the ability to instantaneously control and manipulate film properties enables a process for depositing films having multilayer properties.

[0026] FIG. 1 illustrates a generalized physical vapor deposition (PVD) chamber 100 suitable for sputter depositing materials, also referred to as a “sputtering chamber,” “processing chamber,” or “sputtering processing chamber,” in accordance with one or more embodiments of the present invention. Processing chamber 100 includes a chamber body 108, within which a processing volume 118 is defined. Chamber body 108 has sidewalls 110 and a bottom 146. The dimensions of chamber body 108 and the associated components of processing chamber 100 are not limited and are generally proportionally larger than the size of the substrate 114 to be processed. Any suitable substrate size can be processed, and the size of processing chamber 100 can potentially be unrestricted.

[0027] A lid assembly 104 is mounted on top of chamber body 108. Chamber body 108 can be made of aluminum or other suitable materials. A substrate entry port 130 is formed through sidewall 110 of chamber body 108 to facilitate the transfer of substrate 114 (i.e., a solar panel, flat display substrate, semiconductor wafer, or other workpiece) into and out of processing chamber 100. Entry port 130 can be coupled to a transfer chamber and / or other chambers of a substrate processing system.

[0028] A gas source 128 is coupled to chamber body 108 to supply a processing gas into processing volume 118. In various embodiments, the processing gas can include inert gases, non-reactive gases, and reactive gases. Examples of processing gases that gas source 128 can provide include, but are not limited to, argon (Ar), helium (He), nitrogen (N2), oxygen (O2), hydrogen (H2), and combinations thereof. Other processing gases are contemplated and are included within the scope of the present invention.

[0029] A pumping port 150 is formed through bottom 146 of chamber body 108. A pumping device 152 is coupled to processing volume 118 to evacuate and control the pressure therein. In one embodiment, the pressure level of processing chamber 100 can be maintained in the range of about 10−10 Torr to about 1 Torr. In certain embodiments, the pressure is maintained in the range of about 0.1 mTorr to about 10 mTorr.

[0030] The lid assembly 104 generally includes a target 120 and a ground shield assembly 126 coupled to the target 120. The target 120 provides a source of material that can be sputtered and deposited onto the surface of the substrate 114 during PVD processing. The lid assembly 104 may also include a chamber top plate 127 that can be on top of or around the target 120. In some embodiments, the target 120 can serve as the top plate 127. The target 120 can be placed near the chamber top plate. The target 120 or target plate can be made of a material for depositing substances. A very high frequency (VHF) power source 132 and a high frequency (HF) power source 133 are connected to the target 120 to assist in sputtering material from the target 120. The target 120 can be made of any suitable material, including conductive and non-conductive materials.

[0031] The target 120 generally includes a peripheral portion 124 and a central portion 116. In some embodiments, the peripheral portion 124 is disposed above the sidewall 110 of the chamber. The central portion 116 of the target 120 can have a curved surface that slightly extends toward the surface of the substrate 114 disposed on the substrate support 138. The spacing between the target 120 and the substrate support 138 can be controlled. In some embodiments, the spacing is maintained between about 50 mm and about 150 mm, but other spacings are within the scope of the present invention. Note that the size, shape, material, structure, and diameter of the target 120 can vary for specific processing or substrate requirements. In some embodiments, the target 120 can further include a backplate having a central portion that is bonded and / or made of the material desired to be sputtered onto the substrate surface. The target 120 can also include adjacent bricks or segmented materials that together form the target.

[0032] Optionally, the lid assembly 104 can also include a magnetron assembly 102 mounted above the target 120 that enhances the effective sputtering of material from the target 120 during processing. Examples of magnetron assemblies include linear magnetrons, serpentine magnetrons, helical magnetrons, two-digit magnetrons, rectangular helical magnetrons, and the like.

[0033] The ground shielding assembly 126 of the lid assembly 104 includes a ground frame 106 and a ground shield 112. The ground shielding assembly 126 may also include other chamber shielding members, target shielding members, dark space shielding, and dark space shielding frames. The ground shield 112 is coupled to the peripheral portion 124 by the ground frame 106, defining an upper processing area 154 below the central portion of the target 120 in the processing volume 118. The ground frame 106 electrically insulates the ground shield 112 from the target 120 while providing a ground path to the chamber body 108 of the processing chamber 100 via the sidewall 110. The ground shield 112 confines the plasma generated during processing within the upper processing area 154 and removes target source material from the restricted central portion 116 of the target 120, such that the removed target source is primarily deposited on the substrate surface rather than on the sidewall 110. In one embodiment, the ground shield 112 may be formed by bonding one or more workpiece fragments and / or multiple ones of such workpieces by methods known in the art, such as welding, gluing, high-pressure compression, etc.

[0034] The embodiment shown in FIG. 1 further includes a shaft 140 extending through the bottom 146 of the chamber body 108, and the shaft 140 is coupled to a lift mechanism 144. The lift mechanism 144 is configured to move the substrate support 138 between a lower transfer position and an upper processing position. A bellows 142 externally sheaths the shaft 140 and is coupled to the substrate support 138 to provide a flexible seal therebetween, thereby maintaining the vacuum integrity of the processing volume 118.

[0035] A shadow frame 122 may be disposed on the peripheral region of the substrate support 138 and is configured to limit the deposition of the source material sputtered from the target 120 to a desired portion of the substrate surface. A chamber shield 136 may be disposed on the inner wall of the chamber body 108 and has a lip 156 extending inwardly into the processing volume 118, and the lip 156 is configured to support the shadow frame 122 disposed around the substrate support 138. When the substrate support 138 is raised to the upper position for processing, the outer edge of the substrate 114 disposed on the substrate support 138 is engaged by the shadow frame 122, and the shadow frame 122 is lifted and spaced apart from the chamber shield 136. When the substrate support 138 is lowered to the transfer position adjacent to the substrate inlet 130, the shadow frame 122 is placed back onto the chamber shield 136. Lift pins (not shown) are selectively moved past the substrate support 138 to lift the substrate 114 above the substrate support 138 to facilitate access to the substrate 114 by a transfer robot or other suitable transfer mechanism.

[0036] At least one controller 148 is coupled to the processing chamber 100 and / or its various components. For example, the controller 148 can be configured to control the processing sequence, regulate the gas flow into the chamber 100 from the gas source 128, regulate the power and frequency of the power supply to control the ion bombardment of the target 120, and regulate the density of the plasma and the ionization degree of the sputtered material.

[0037] In some embodiments, there is more than one controller 148 connected to the respective components, and the main control processor is coupled to each individual controller to control the chamber 100. The controller 148 can be one of any form of general-purpose computer processor that can be used in an industrial setting to control various chambers and sub-processors.

[0038] At least one controller 148 can have a processor 160, a memory 158 coupled to the processor 160, an input / output device coupled to the processor 160, and support circuitry 162 to communicate between different electronic components. The memory 158 can include one or more of transient memory (e.g., random access memory) and non-transient memory (e.g., a storage).

[0039] The memory 158 of the processor 160 or the computer-readable medium can be one or more types of readily available memories, such as random access memory (RAM), read-only memory (ROM), disk drives, hard disks, or any other form of digital storage located locally or remotely. The memory 158 can retain an instruction set that can be operated by the processor 160 to control the parameters and components of the chamber 100. The support circuitry 162 is coupled to the processor 160 to support the processor in a conventional manner. The circuitry can include, for example, a cache, a power supply, a clock circuit, an input / output system, subsystems, and the like.

[0040] The processing can be stored in the memory as a software routine that, when executed by the processor, causes the processing chamber to perform the processing of the present disclosure. The software routine can also be stored and / or executed by a second processor located remotely from the hardware controlled by the processor.

[0041] Some or all of the methods of the present disclosure can also be implemented in hardware. Thus, the processing can be implemented in software and can be executed using a computer system, can be implemented in hardware (e.g., an application-specific integrated circuit or other type of hardware implementation), or can be implemented in a combination of software and hardware. When executed by the processor, the software routine transforms a general-purpose computer into a dedicated computer (controller) that controls the operation of the chamber to perform the processing.

[0042] In some embodiments, the controller 148 has one or more configurations to perform separate processes or sub - processes to execute the method. The controller 148 can be connected to and configured to operate intermediate components to perform the functions of the method. For example, the controller 148 can be connected to and configured to control one or more of a gas valve, an actuator, a motor, a slit valve, a vacuum controller, a power supply.

[0043] During processing, the material sputtered from the target 120 is ionized in the plasma and deposited on the surface of the substrate 114. The target 120 and the substrate support 138 are biased relative to ground by the VHF power supply 132 and the HF power supply 133 to maintain the plasma formed by the process gas provided by the gas source 128, form ions within the plasma, and direct the ions to sputter onto the substrate 114. The ions and excited species in the plasma strike the target 120, causing the target material to be removed from the target 120. The removed target material and the process gas undergo high - energy collisions within the plasma, resulting in the formation of ionic target material, which accelerates towards the substrate 114, thereby forming a layer on the substrate 114 having the same composition as the target 120.

[0044] One or more embodiments of the present invention relate to a method for processing a substrate in a physical vapor deposition (PVD) vacuum chamber 100. A target 120 is disposed near the top plate 127 of the chamber. Alternatively, the target 120 can be used as the top plate 127 of the chamber 100, or the top plate 127 can be located above the magnetron assembly 102. The substrate 114 is placed on a substrate support 138 facing the target 120. A process gas from a process gas source 128 is introduced into the chamber 100 to a selected pressure. The pressure of the process gas is adjusted to be high enough to cause ionization of most of the material sputtered from the target. A first power at a first frequency having a high enough frequency to excite target electrons is applied to the target to maintain a capacitively - coupled high - density plasma. A second power is applied to the substrate at a second frequency lower than the first frequency to generate a sheath potential sufficient to sputter ions from the target onto the substrate to deposit a sputtered ion film from the target. One or more of the selected pressure and the sheath potential can be controlled to control the microstructure of the deposited film.

[0045] In a particular embodiment, the power supplied to the target substantially does not include a DC component. When DC electricity is supplied especially to a target made of a non - conductive material, an arc may be generated in the chamber. Arc discharge typically damages the sputtered substrate. Embodiments of these methods are capable of generating and adjusting plasma density and sputtering rate without using DC power.

[0046] The target material is selected based on the desired film to be formed. Sputtering is characterized in that the formed film has the same composition as the target. Thus, the target can be a metal, a pure substance, a doped substance, etc., such that the film is formed of the same material. In one or more embodiments, the target is selected from silicon, doped silicon, zinc oxide, indium tin oxide, transparent conductive oxide, metal, and combinations thereof. In a detailed embodiment, the target is silicon with or without a dopant.

[0047] The substrate holder 138 may include a heating or cooling system to allow changing the temperature of the substrate holder 138 and the substrate 114. In one or more embodiments of the present invention, the temperature of the substrate is controlled. Those skilled in the art will recognize suitable processing parameters, including power, frequency, temperature, pressure, etc.

[0048] Some embodiments of the present disclosure relate to a plasma cathode assembly. The plasma cathode assembly described herein can be understood as the cover assembly 104 of the above-described processing chamber 100.

[0049] FIG. 2 illustrates a plasma cathode assembly 200 according to one or more embodiments of the present disclosure. The plasma cathode assembly 200 includes a cathode housing 210 having a top 212, a sidewall 214, and a backplate 216 surrounding an internal volume 220 having a central axis 215. In some embodiments, the backplate 216 is configured to support the target 230 during the sputtering process.

[0050] The plasma cathode assembly 200 also includes a first EM coil 240 located within the internal volume 220 of the cathode housing 210. The first EM coil 240 has a first inner diameter 242 and a first outer diameter 244 defining a first coil width W1, and a first bottom surface 246 and a first top surface 248 defining a first coil thickness T1.

[0051] The plasma cathode assembly 200 includes a second EM coil 250 within the internal volume 220 of the cathode housing 210. The second EM coil 250 has a second inner diameter 252 and a second outer diameter 254 defining a second coil width W2, and a second bottom surface 256 and a second top surface 258 defining a second coil thickness T2.

[0052] The first EM coil 240 is within the second inner diameter 252 of the second EM coil 250. While FIG. 2 illustrates three EM coils, note that for some embodiments of the present disclosure, only two EM coils are required.

[0053] In some embodiments, the plasma cathode assembly 200 also includes at least one additional EM coil 260 within the internal volume 220 of the cathode housing 210. Each additional EM coil has an inner diameter and an outer diameter that define a coil width, and a bottom surface and a top surface that define a coil thickness. In addition, the position of each additional EM coil should ensure that at least one of the first EM coil 240 or the second EM coil 250 is within the inner diameter of the additional EM coil 260. In some embodiments, the plasma cathode includes more than two EM coils. In some embodiments, the plasma cathode includes six or more EM coils.

[0054] FIG. 5 illustrates a plasma cathode assembly 500 having six coils (510 - 560). In some embodiments, the outermost coil 560 is located near the outer diameter 234 of the target 230 on the backplate 216. In this regard, "near" means that the diameter of the outer coil 560 is within ±5%, within ±2%, within ±1%, or within ±0.5% of the diameter of the target 230.

[0055] In some embodiments, the outermost coil 560 is located outside the outer diameter 234 of the target 230 on the backplate 216. In some embodiments, the outermost coil 560 is located inside the outer diameter 234 of the target 230 on the backplate 216. In this regard, when the outermost coil 560 is located inside or outside the outer diameter 234 of the target 230, the coil 560 and the target 230 are concentric with a target having an outer diameter 234 that is larger or smaller than the inner diameter of the outermost coil 560.

[0056] In some embodiments, the inner coils (510 - 550) run in a first direction, while the outermost coil 560 runs in an opposite second direction. Without being bound by theory, it is believed that placing the coils outside the cathode face and extending them in opposite directions allows for the suppression of the magnetic field. Suppressing the magnetic field reduces the amount of material deposited on the processing kit.

[0057] Although the specification and the drawings discuss and illustrate circular EM coils, the present disclosure is not limited to EM coils of any particular shape. The coils can be circular, elliptical, polygonal, or any combination thereof.

[0058] In addition, although the specification and the drawings discuss and illustrate EM coils in a shared plane, the present disclosure is not limited to EM coils in a shared plane. The coils can be vertically moved so that they completely overlap (as shown), partially overlap, or do not vertically overlap.

[0059] In some embodiments, as shown in FIG. 2, the first EM coil 240 and the second EM coil 250 are concentrically positioned. In some embodiments, the first EM coil 240 and the second EM coil 250 are non-concentrically positioned.

[0060] In some embodiments, the center of one or both of the EM coils 240, 250 is on the central axis 215. In some embodiments, neither the center of the first EM coil 240 nor the center of the second EM coil 250 is at the central axis.

[0061] In some embodiments, at least one of the first EM coil 240 and the second EM coil 250 is movable relative to the cathode housing 210. In some embodiments, at least one coil translates. The translational movement described herein can be understood to include movement in a plane perpendicular to the central axis 215. In some embodiments, at least one EM coil rotates. The rotation described herein can be understood to be a rotation about an axis parallel to the central axis 215.

[0062] Without being bound by theory, it is believed that the movement of the EM coil enabled during processing may allow the resulting magnetic field to be distorted. In other words, the movement of the enabled EM coil can change the shape of the resulting magnetic field. As shown in FIGS. 3A to 3C, it can be understood that when a bar magnet is rapidly translated in a circular motion, the magnetic field generated by it is distorted as shown in FIGS. 3B and 3C.

[0063] As used herein, the term EM coil refers to a coil of conductive material. When current passes through the material, the enabled EM coil will operate as an electromagnet.

[0064] Some embodiments of the present disclosure relate to a processing chamber that includes a plasma cathode assembly as disclosed herein.

[0065] As described above with respect to FIG. 1, some embodiments of the present disclosure relate to a plasma processing chamber. In some embodiments, the plasma processing chamber includes a chamber body 108, the chamber body 108 includes a bottom 146, side walls 110, and a top plate 127, and the top plate 127 encloses a processing volume 118.

[0066] The plasma processing chamber also includes a substrate support 138 located within the processing volume 118. In some embodiments, the plasma processing chamber includes a plasma cathode assembly 200 located above the substrate support 138. The plasma cathode assembly 200 is as described above.

[0067] Some embodiments of the present disclosure provide methods for tuning a plasma profile. In some embodiments, the methods use a plasma cathode assembly described elsewhere herein.

[0068] Methods of controlling a plasma profile include one or more of the following: controlling the spacing of EM coils within a plasma cathode assembly; modulating the direction or amount of current flowing through one or more EM coils within the plasma cathode assembly; or controlling the position of the EM coils within the plasma cathode assembly.

[0069] Controlling the spacing of the EM coils can include passing current through non-adjacent coils without passing current through the coils therebetween. For example, a plasma cathode assembly can include six successively larger-sized EM coils. The outermost coil (loop 6) and the innermost coil (loop 1) can be enabled, while the other coils are not enabled. Loops 6 and 4, loop 3, and / or loop 2 can also be enabled. Each resulting magnetic field is expected to have a different effect on the resulting plasma profile during processing.

[0070] In some embodiments, the plasma profile is controlled by modulating the direction or amount of current flowing through one or more EM coils within the plasma cathode assembly. For example, a predetermined EM coil can have an alternating current flowing through the coil to enable the EM coil. The alternating current is expected to produce a magnetic field different from that of a direct current. Similarly, a pulsed current (high / low or on / off) is expected to produce a magnetic field different from that of a steady current.

[0071] In some embodiments, the plasma profile is controlled by controlling the position of the EM coils within the plasma cathode assembly. In some embodiments, the position of the EM coils can be controlled only before plasma processing occurs. In such embodiments, the EM coils can be arranged concentrically or "off-center" with respect to other EM coils or from the cathode housing. As the number of EM coils increases, the spatial options grow exponentially. Each of these spatial arrangements provides a different plasma profile.

[0072] In addition, in some embodiments, the position of the EM coils can be controlled during plasma processing. In such embodiments, the EM coils can be rotated or translated. Such movements are described in more detail above. As shown in FIGS. 3B and 3C, a rotating bar magnet provides a distorted magnetic field compared to a fixed bar magnet. Such modifications in the magnetic field allow control of the plasma profile because the moving magnet may be able to provide a distorted magnetic field, thereby providing shapes that would otherwise not be achievable.

[0073] Similarly, in some embodiments, the plasma cathode assembly 200 also includes at least one permanent magnet. In some embodiments, at least one permanent magnet is located within the first inner diameter 242 of the first EM coil 240. In some embodiments, at least one permanent magnet rotates about the central axis 215.

[0074] As shown in FIGS. 4A and 4B, when there is at least one magnet, the magnet provides a distorted magnetic field. FIG. 4A shows a top view of the magnetic field when the inner coil 410 and the outer coil 420 are operating with opposite currents. For simplicity, the inner coil 410 and the outer coil 420 are shown as the center lines of the coils. In FIG. 4A, the tangential magnetic field 450 is shown as a dashed line, which is generally circular and concentric with the inner coil 410 and the outer coil 420.

[0075] In contrast, FIG. 4B shows a top view of the magnetic field when a plurality of permanent magnets 430 are placed within the inner coil 410. For the simulation results shown in FIG. 4B, the permanent magnet 430A has a south pole closest to the viewer, and the permanent magnet 430B has a north pole closest to the viewer. The tangential magnetic field 450 (shown as a dashed line) is "D-shaped", with one side bent inward by the permanent magnet 430.

[0076] In some embodiments, the method of adjusting the plasma profile adjusts one or more of the plasma position or the plasma density. In some embodiments, the tuned plasma profile allows for the uniform erosion of the target material.

[0077] Existing magnetron arrangements do not allow the target material at the target edge to be affected by the magnetic field generated by the magnetron. This results in an erosion profile that does not affect the target edge as severely as other parts. Without being bound by theory, the EM coil enables a tangential magnetic field directly below the coil, thereby allowing erosion up to and including the target edge.

[0078] References in this specification to "in one embodiment", "in some embodiments", "in one or more embodiments", or "in an embodiment" etc., mean that the particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases "in one or more embodiments", "in some embodiments", "in one embodiment", or "in an embodiment" etc. throughout this specification are not necessarily referring to the same embodiment of the present disclosure. Furthermore, the particular features, structures, configurations, or characteristics may be combined in any suitable manner in one or more embodiments.

[0079] Although the content disclosed herein relates to specific embodiments, those of ordinary skill in the art of the present invention should understand that these embodiments are only used to illustrate the principles and applications of the present disclosure. It will be apparent to those of ordinary skill in the art of the present invention that various modifications and variations can be made to the methods and apparatuses of the present disclosure without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure may cover such modifications and variations as long as such modifications and variations are within the scope of the appended claims and their equivalents.

[0080] 100: Physical Vapor Deposition (PVD) Chamber 102: Magnetron Assembly 104: Cover Assembly 106: Grounding Frame 108: Chamber Body 110: Side Wall 112: Grounding Shield 114: Substrate 116: Central Portion 118: Processing Volume 120: Target 124: Peripheral Portion 126: Grounding Shield Assembly 127: Top Plate 128: Processing Gas Source 130: Substrate Inlet Port 132: Very High Frequency (VHF) Power Source 133: High Frequency (HF) Power 136: Chamber Shield 138: Substrate Holder 140: Axis 142: Bellows 144: Lifting Mechanism 146: Bottom 148: Controller 150: Pumping Port 152: Pumping Device 154: Upper Processing Region 156: Lip 158: Memory 160: Processor 162: Support Circuit 200: Plasma Cathode Assembly 210: Cathode Housing 212: Top 214: Side Wall 215: Central axis 216: Backplate 220: Internal volume 230: Target 240: First EM coil 242: First inner diameter 244: First outer diameter 246: First bottom surface 248: First top surface 250: Second EM coil 252: Second inner diameter 254: Second outer diameter 256: Second bottom surface 258: Second top surface 260: Additional EM coil 410: Internal coil 420: External coil 430: Permanent magnet 450: Tangential magnetic field 500: Plasma cathode assembly 510: Coil 520: Coil 530: Coil 540: Coil 550: Coil 560: Coil 430A: Permanent magnet 430B: Permanent magnet

Claims

1. A method for adjusting a plasma profile, the method comprising one or more of the following steps: controlling the spacing of EM coils within a plasma cathode assembly; modulating a direction or magnitude of the current flowing through the EM coils of the plasma cathode assembly; and controlling a position of the EM coils within the plasma cathode assembly.

2. The method as described in claim 1, wherein the step of controlling the interval of the EM coils comprises the following steps: allowing current to flow through non-adjacent coils but not through coils in between.

3. The method as described in claim 1, wherein the step of controlling the position of the EM coil includes the step of moving the EM coil by translation or rotation.

4. The method as described in claim 1, wherein the plasma density is tuned.

5. The method as described in claim 1, wherein the plasma position is tuned.

6. The method as described in claim 1, wherein total erosion is achieved.

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