Multizone magnetron assembly
The present invention generally provides an apparatus and method for processing a surface of a substrate in physical vapor deposition (PVD) chamber that has a magnetron assembly that has separately positionable magnetron sections to improve the deposition uniformity. In general, aspects of the present invention can be used for flat panel display processing, semiconductor processing, solar cell processing, or any other substrate processing. In one aspect, the processing chamber contains one or more magnetron sections and magnetron actuators that are used to increase and more evenly distribute the magnetic field strength throughout the processing region of the processing chamber during processing.
This application claims benefit of U.S. Provisional Patent Application Ser. No. 60/714,979, filed Sep. 7, 2005, which is herein incorporated by reference.
BACKGROUND OF THE INVENTION1. Field of the Invention
Embodiments of the present invention generally relate to substrate plasma processing apparatuses and methods that are adapted to deposit a film on a surface of a substrate.
2. Description of the Related Art
Physical vapor deposition (PVD) using a magnetron is one of the principal methods of depositing metal onto a semiconductor integrated circuit to form electrical connections and other structures in an integrated circuit device. During a PVD process a target is electrically biased so that ions generated in a process region can bombard the target surface with sufficient energy to dislodged atoms from the target. The process of biasing a target to cause the generation of a plasma that causes ions to bombard and remove atoms from the target surface is commonly called sputtering. The sputtered atoms travel generally toward the wafer being sputter coated, and the sputtered atoms are deposited on the wafer. Alternatively, the atoms react with a gas in the plasma, for example, nitrogen, to reactively deposit a compound on the wafer. Reactive sputtering is often used to form thin barrier and nucleation layers of titanium nitride or tantalum nitride on the substrate.
Direct current (DC) magnetron sputtering is the most usually practiced commercial form of sputtering. The metallic target is biased to a negative DC bias in the range of about −100 to −600 VDC to attract positive ions of the working gas (e.g., argon) toward the target to sputter the metal atoms. Usually, the sides of the sputter chamber are covered with a shield to protect the chamber walls from sputter deposition. The shield is typically electrically grounded and thus provides an anode in opposition to the target cathode to capacitively couple the DC target power to the plasma generated in the sputter chamber.
A magnetron having at least a pair of opposed magnetic poles is typically disposed near the back of the target to generate a magnetic field close to and parallel to the front face of the target. The induced magnetic field from the pair of opposing magnets trap electrons and extend the electron lifetime before they are lost to an anodic surface or recombine with gas atoms in the plasma. Due to the extended lifetime, and the need to maintain charge neutrality in the plasma, additional argon ions are attracted into the region adjacent to the magnetron to form there a high-density plasma. Thereby, the sputtering rate is increased.
However, conventional sputtering presents challenges in the formation of advanced integrated circuits on large area substrates, such a flat panel display substrates. Typically, for TFT applications, the substrate is a glass substrate with a surface area greater than about 2000 cm2. Commonly, TFT processing equipment is generally configured to accommodate substrates up to about 1.5×1.8 meters. However, processing equipment configured to accommodate substrate sizes up to and exceeding 2.16×2.46 meters, is envisioned in the immediate future. One issue that arises is that it is generally not feasible to create a chamber big enough to maintain the surface area ratio of the cathode (target) to anode surface area commonly used in conventional sputter processing chambers. Trying to maintain the surface area ratio can lead to manufacturing difficulties due to the large size of the parts required to achieve the desired area ratio and processing problems related to the need to pump down such a large volume to a desired base pressure prior to processing. The reduced surface area of the anode relative to the large target surface area generally causes the density of the plasma generated in the processing region, which is generally defined as the region below the target and above the substrate, to vary significantly from the center of the target to the edge of the target. Since the anodic surfaces are commonly distributed around the periphery of the target, it is believed that the larger distance from the center of the target to the anodic surfaces, makes the emission of electrons from the target surface at the edge of the target more favorable, and thus reduces the plasma density near the center of the target. The reduction in plasma density in various regions across the target face will reduce the number of ions striking the surface of the target in that localized area and thus varying the uniformity of the deposited film across the surface of a substrate that is positioned a distance from the target face. The insufficient anode area problem will thus manifest itself as a film thickness non-uniformity that is smaller near the center of the substrate relative to the edge.
Therefore, there is a need for a method and apparatus that can improve the uniformity of the PVD deposited film.
SUMMARY OF THE INVENTIONThe present invention generally provides a plasma processing chamber assembly for depositing a layer on a substrate comprising a plasma processing chamber having a processing region, a target positioned on the plasma processing chamber so that a surface of the target is in contact with the processing region, a magnetron assembly positioned near the target, wherein the magnetron assembly comprises a magnetron section that has one or more magnets that are magnetically coupled to the processing region, and an actuator that is adapted to position the magnetron section in a direction generally perpendicular to the surface of the target, and a substrate support positioned inside the plasma processing region, wherein the substrate support is adapted to support a substrate on a substrate supporting surface.
Embodiments of the invention may further provide a plasma processing chamber assembly for depositing a layer on a substrate comprising a plasma processing chamber having a processing region, a target positioned on the plasma processing chamber so that a surface of the target is in contact with the processing region, a magnetron assembly positioned near the target, wherein the magnetron assembly comprises a first magnetron section that has one or more magnets that are magnetically coupled to the processing region, a second magnetron section that has one or more magnets that are magnetically coupled to the processing region, a first actuator that is adapted to position the first magnetron section in a direction generally perpendicular to the surface of the target, and a second actuator that is adapted to position the first magnetron section in a direction generally parallel to the surface of the target, and a substrate support positioned inside the plasma processing region, wherein the substrate support is adapted to support a substrate on a substrate supporting surface.
Embodiments of the invention may further provide a plasma processing chamber assembly for depositing a layer on a substrate comprising a plasma processing chamber having a processing region, a target positioned on the plasma processing chamber so that a surface of the target is in contact with the processing region, a magnetron assembly positioned near to the target, wherein the magnetron assembly comprises a first magnetron section that has one or more magnets that are magnetically coupled to the processing region, a second magnetron section that has one or more magnets that are magnetically coupled to the processing region, wherein the first magnetron section is nested within the second magnetron section, a first actuator that is adapted to position the first magnetron section in a direction generally perpendicular to the surface of the target, and a second actuator that is adapted to position the first magnetron section and the second magnetron section in a direction generally parallel to the surface of the target, and a substrate support positioned inside the plasma processing region, wherein the substrate support is adapted to support a substrate on a substrate supporting surface.
Embodiments of the invention may further provide a method of depositing a layer on a surface of a substrate, comprising providing a target that has a surface that contacts a processing region, providing a magnetron section that is magnetically coupled to the processing region through the target, depositing a conductive layer on a surface of a substrate that is positioned in the processing region, and adjusting the position the magnetron section in a direction generally perpendicular to the surface of the target to improve the deposition uniformity across the surface of the substrate.
Embodiments of the invention may further provide a method of depositing a layer on a surface of a substrate, comprising providing a target that has a surface that contacts a processing region, providing a magnetron section that is magnetically coupled to the processing region through the target, moving the magnetron section in a direction that is generally parallel to the surface of the target by use of an actuator, depositing a conductive layer on a surface of a substrate that is positioned in the processing region, and adjusting the position of the magnetron section in a direction generally perpendicular to the surface of the target while the magnetron is moving in a direction that is generally parallel to the surface of the target to improve the deposition uniformity across the surface of the substrate.
BRIEF DESCRIPTION OF THE DRAWINGSSo that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
The present invention generally provides an apparatus and method for processing a surface of a substrate in a PVD chamber that has a magnetron assembly that has separately positionable magnetron sections to improve the deposition uniformity. In general, aspects of the present invention can be used for flat panel display processing, semiconductor processing, solar cell processing, or any other substrate processing. The invention is illustratively described below in reference to a physical vapor deposition system, for processing large area substrates, such as a PVD system, available from AKT, a division of Applied Materials, Inc., Santa Clara, Calif. In one embodiment, the processing chamber is adapted to process substrates that have a surface area of at least about 2000 cm2. In another embodiment, the processing chamber is adapted to process substrates that have a surface area of at least about 19,500 cm2 (e.g., 1300 mm×1500 mm). In one aspect, the processing chamber is adapted to process rectangular substrates. However, it should be understood that the apparatus and method may have utility in other system configurations, including those systems configured to process large area round substrates.
Increased Anode Area Hardware
A. Lower Chamber Assembly Hardware
The lower chamber assembly 35 generally contains a substrate support assembly 60, chamber body assembly 40, a shield 50, a process gas delivery system 45 and a shadow frame 52. The shadow frame 52 is generally used to shadow the edge of the substrate to prevent or minimize the amount of deposition on the edge of a substrate 12 and substrate support 61 during processing (see
The substrate support assembly 60 generally contains a substrate support 61, a shaft 62 that is adapted to support the substrate support 61, and a bellows 63 that is sealably connected to the shaft 62 and the chamber base 42 to form a moveable vacuum seal that allows the substrate support 61 to be positioned in the lower chamber assembly 35 by the lift mechanism 65. The lift mechanism 65 may contain a conventional linear slide (not shown), pneumatic air cylinder (not shown) and/or DC servo motor that is attached to a lead screw (not shown), which are adapted to position the substrate support 61, and substrate 12, in a desired position in the processing region 15. In one embodiment, the substrate support 61 may contain RF biasable elements 61A embedded within the substrate support 61 that can be used to capacitively RF couple the substrate support 61 to the plasma generated in the processing region 15 by use of an RF power source 67 and RF matching device 66. The ability to RF bias the substrate support 61 may be useful to help improve the plasma density, improve the deposition profile on the substrate, and increase the energy of the deposited material at the surface of the substrate.
Referring to
To control the various processing chamber 10 components and process variables during a deposition process, a controller 101 is used. The processing chamber's processing variables may be controlled by use of the controller 101, which is typically a microprocessor-based controller. The controller 101 is configured to receive inputs from a user and/or various sensors in the plasma processing chamber and appropriately control the plasma processing chamber components in accordance with the various inputs and software instructions retained in the controller's memory. The controller 101 generally contains memory and a CPU which are utilized by the controller to retain various programs, process the programs, and execute the programs when necessary. The memory is connected to the CPU, and may be one or more of a readily available memory, such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or any other form of digital storage, local or remote. Software instructions and data can be coded and stored within the memory for instructing the CPU. The support circuits are also connected to the CPU for supporting the processor in a conventional manner. The support circuits may include cache, power supplies, clock circuits, input/output circuitry, subsystems, and the like all well known in the art. A program (or computer instructions) readable by the controller 101 determines which tasks are performable in the plasma processing chamber. Preferably, the program is software readable by the controller 101 and includes instructions to monitor and control the plasma process based on defined rules and input data.
B. Lid Assembly and Magnetron Hardware
The lid assembly 20 generally contains a target 24, a lid enclosure 22, a ceramic insulator 26, one or more o-ring seals 29 and a magnetron assembly 23 that are positioned in a target backside region 21. In one aspect, the ceramic insulator 26 is not required to provide electrical isolation between the backing plate 24B of the target 24 and the chamber body assembly 40. In one aspect of the process chamber 10, a vacuum pump 25 (
The sputter deposited film uniformity can be affected by the deflection, or bowing, of the target since it will cause the magnetic field strength generated by a conventional planar magnetron to vary from the center to the edge of a target 24 since the center of the target is moving a farther distance away from the conventional planar magnetron than the edge of the target and thus the magnetic field strength in the processing region 15 will be reduced in the center region of the target. The reduction in magnetic field strength will affect the plasma density uniformity across the target surface 24C and thus the sputter deposition profile on the processing surface of the substrate. To resolve this issue, embodiments of the invention utilize a magnetron assembly 23 that contain two or more magnetron sections (e.g., elements 301A-C) that are positionable relative to the target backside surface 24D, and thus the target surface 24C and processing region 15. In one embodiment, the magnetron assembly 23 will contain two or more magnetron sections (e.g., three shown in
The magnetron sections 301 have an effect on the shape and uniformity of the PVD deposited layer due to the strength and orientation of the magnetic fields generated by the magnetron sections in the magnetron assembly 23. In general, each of the magnetron sections will contain at least one magnet 27. The magnets 27 may be permanent magnets (e.g., neodymium, samarium-cobalt, ceramic, or Alnico) or electromagnets. In one embodiment of the processing chamber 10, each magnetron section is adapted to deliver a constant or varying magnetic field strength using electromagnets as a function of time and/or position relative to the center of the target 24. In this configuration the single magnetron assembly 23 may contain two or more regions that have differing magnetic field strengths that are optimized to achieve a desired plasma density and sputter deposition profile. The term sputter deposition profile is intended to describe the deposited film thickness as measured across the substrate processing surface (element 12A in
Referring to
In one aspect, the magnetron assembly 23 is smaller in size than the target 24 and is translated across the back of the target 24 to assure full utilization of the target surface 24C. Referring to
In another embodiment, the magnetron sections 301 are translated in at least one of the directions that are perpendicular (Z-direction) to the target surface 24C by use of one or more vertical magnetron actuators 34B. The ability to position a magnetron section (e.g., 301A, 301B, 301C) in a position perpendicular to the target surface 24C will affect the magnetic field strength formed in the processing region 15 and thus the plasma density in the regions below the target surface 24C. Generally, by moving the magnetron section(s) closer to the target 24 will increase the magnetic field strength in the processing region 15 while moving the magnet farther away from the target 24 will reduce the magnetic field strength passing through the processing region 15. Therefore, by adjusting the position of each of the magnetron sections (e.g., elements 301A-301C in
In one embodiment, the position of the magnetron sections 301 can be adjusted in the X, Y and Z directions (
Referring to
In one embodiment, the magnets 27 in the magnetron sections (elements 301A-C) are electromagnets that may be translated or remain stationary over the target section(s) during processing. In one aspect, the magnetic field (B-Field) generated by the electromagnets can be dynamically adjusted during different phases of the deposition process, by adjusting the current passing through the plurality conductive coils contained in the electromagnet. In another aspect, the magnetic field generated by the electromagnets (element 27) can be dynamically adjusted as a function of position of the magnetron section 301 over its target 24. For example, the magnetron assembly's magnetic field strength may be reduced as magnetron section 301 is translated to positions that are near an edge of a target 24 (element “E”) to reduce the interaction between the adjacent magnetron sections or other chamber components. The ability to adjust the magnetic field strength as a function of translational position can help to improve the deposition uniformity and reduce the interaction between the various target sections.
To perform a PVD deposition process, the controller 101 commands the vacuum pumping system 44 to evacuate the processing chamber 10 to a predetermined pressure/vacuum so that the plasma processing chamber 10 can receive a substrate 12 from a system robot (not shown) mounted to a central transfer chamber (not shown) which is also under vacuum. To transfer a substrate 12 to the processing chamber 10 the slit valve (element 46), which seals off the processing chamber 10 from the central transfer chamber, opens to allow the system robot to extend through the access port 32 in the chamber wall 41. The lift pins 74 then remove the substrate 12 from the extended system robot, by lifting the substrate from the extended robot blade (not shown). The system robot then retracts from the processing chamber 10 and the slit valve 46 closes to isolate the processing chamber 10 from the central transfer chamber. The substrate support 61 then lifts the substrate 12 from the lift pins 74 and moves the substrate 12 to a desired processing position below the target 24. The position of the magnetron sections 301 may then be adjusted or continually varied as a function of time in the X, Y and/or Z directions to achieve a desired magnetic field in the processing region 15. Then after a achieving a desired base pressure, a desired flow of a processing gas is injected into the processing region 15 and a bias voltage is applied to the target 24 by use of a power supply 28 to generate a plasma in the processing region 15. The application of a DC bias voltage by the power supply 28 causes the gas ionized in the processing region 15 to bombard the target surface and thus “sputter” metal atoms that land on the processing surface 12A of the substrate positioned on the surface of the substrate support 61.
Magnetron Sections
In one embodiment, as illustrated in
The plasma loop formed by the magnetron shapes illustrated in
Coordinated Motion
In one embodiment, the position of a magnetron section (e.g., 301A-B) in the Z-direction is adjusted relative to its position in the X-direction and/or Y-direction to account for the bow of the target 24, or just to adjust the deposition uniformity. For example, referring to
In one embodiment, it may be desirable to define one or more desired trajectory paths (element “D” in
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
Claims
1. A plasma processing chamber assembly for depositing a layer on a substrate comprising:
- a plasma processing chamber having a processing region;
- a target positioned on the plasma processing chamber so that a surface of the target is in contact with the processing region;
- a magnetron assembly positioned near the target, wherein the magnetron assembly comprises: a magnetron section that has one or more magnets that are magnetically coupled to the processing region; and an actuator that is adapted to position the magnetron section in a direction generally perpendicular to the surface of the target; and
- a substrate support positioned inside the plasma processing region, wherein the substrate support is adapted to support a substrate on a substrate supporting surface.
2. The plasma processing chamber assembly of claim 1, the substrate support is adapted to support a substrate that has a processing surface that has a surface area of at least 19,500 cm2.
3. The plasma processing chamber assembly of claim 1, further comprising an actuator that is adapted to position the magnetron section in a direction generally parallel to the surface of the target.
4. The plasma processing chamber assembly of claim 1, wherein the magnetron section has a first pole and a second pole that is magnetically coupled to the processing region through the target, wherein the first pole and the second pole are adapted to form a plasma loop that has a serpentine shape.
5. The plasma processing chamber assembly of claim 1, wherein the magnetron section has a first pole and a second pole that is magnetically coupled to the processing region through the target, wherein the first pole and the second pole are adapted to form a plasma loop that has a spiral shape.
6. A plasma processing chamber assembly for depositing a layer on a substrate comprising:
- a plasma processing chamber having a processing region;
- a target positioned on the plasma processing chamber so that a surface of the target is in contact with the processing region;
- a magnetron assembly positioned near the target, wherein the magnetron assembly comprises: a first magnetron section that has one or more magnets that are magnetically coupled to the processing region; a second magnetron section that has one or more magnets that are magnetically coupled to the processing region; a first actuator that is adapted to position the first magnetron section in a direction generally perpendicular to the surface of the target; and a second actuator that is adapted to position the first magnetron section in a direction generally parallel to the surface of the target; and
- a substrate support positioned inside the plasma processing region, wherein the substrate support is adapted to support a substrate on a substrate supporting surface.
7. The plasma processing chamber assembly of claim 6, the substrate support is adapted to support a substrate that has a processing surface that has a surface area of at least 19,500 cm2.
8. The plasma processing chamber assembly of claim 6, further comprising a third actuator that is adapted to position the second magnetron section in a direction generally perpendicular to the surface of the target.
9. The plasma processing chamber assembly of claim 6, wherein the first magnetron section has a first pole and a second pole that is magnetically coupled to the processing region through the target, wherein the first pole and the second pole are adapted to form a plasma loop that has a serpentine shape.
10. The plasma processing chamber assembly of claim 6, wherein the first magnetron section has a first pole and a second pole that is magnetically coupled to the processing region through the target, wherein the first pole and the second pole are adapted to form a plasma loop that has a spiral shape.
11. The plasma processing chamber assembly of claim 6, wherein the second actuator is also adapted to position the second magnetron section in a direction parallel to the target surface.
12. The plasma processing chamber assembly of claim 6, wherein the first magnetron section is positioned over a center region of the target and the second magnetron section is positioned of an edge region, wherein the magnetic field strength delivered by at least a portion of the first magnetron section to the processing region is greater than the magnetic field strength delivered by the second magnetron section to the processing region.
13. A plasma processing chamber assembly for depositing a layer on a substrate comprising:
- a plasma processing chamber having a processing region;
- a target positioned on the plasma processing chamber so that a surface of the target is in contact with the processing region;
- a magnetron assembly positioned near to the target, wherein the magnetron assembly comprises: a first magnetron section that has one or more magnets that are magnetically coupled to the processing region; a second magnetron section that has one or more magnets that are magnetically coupled to the processing region, wherein the first magnetron section is nested within the second magnetron section; a first actuator that is adapted to position the first magnetron section in a direction generally perpendicular to the surface of the target; and a second actuator that is adapted to position the first magnetron section and the second magnetron section in a direction generally parallel to the surface of the target; and
- a substrate support positioned inside the plasma processing region, wherein the substrate support is adapted to support a substrate on a substrate supporting surface.
14. The plasma processing chamber assembly of claim 13, the substrate support is adapted to support a substrate that has a processing surface that has a surface area of at least 19,500 cm2.
15. The plasma processing chamber assembly of claim 13, further comprising a third actuator that is adapted to position the second magnetron section in a direction generally perpendicular to the surface of the target.
16. The plasma processing chamber assembly of claim 13, wherein the first magnetron section has a first pole and a second pole that is magnetically coupled to the processing region through the target, wherein the first pole and the second pole are adapted to form a plasma loop that has a serpentine shape.
17. The plasma processing chamber assembly of claim 13, wherein the first magnetron section has a first pole and a second pole that is magnetically coupled to the processing region through the target, wherein the first pole and the second pole are adapted to form a plasma loop that has a spiral shape.
18. The plasma processing chamber assembly of claim 13, wherein the second magnetron section has a first pole and a second pole that is magnetically coupled to the processing region through the target, wherein the first pole and the second pole are adapted to form a plasma loop that has a spiral shape.
19. The plasma processing chamber assembly of claim 13, wherein the first magnetron section is positioned over a center region of the target and the second magnetron section is positioned of an edge region, wherein the magnetic field strength delivered by at least a portion of the first magnetron section to the processing region is greater than the magnetic field strength delivered by the second magnetron section to the processing region.
20. A method of depositing a layer on a surface of a substrate, comprising:
- providing a target that has a surface that contacts a processing region;
- providing a magnetron section that is magnetically coupled to the processing region through the target;
- depositing a conductive layer on a surface of a substrate that is positioned in the processing region; and
- adjusting the position the magnetron section in a direction generally perpendicular to the surface of the target to improve the deposition uniformity across the surface of the substrate.
21. The method of claim 20, further comprising:
- providing a second magnetron section that is magnetically coupled to the processing region through the target; and
- adjusting the position the second magnetron section in a direction generally perpendicular to the surface of the target to improve the deposition uniformity across the surface of the substrate.
22. The method of claim 20, wherein the step of adjusting the position the magnetron section in a direction generally perpendicular to the surface of the target is continually controlled by use of a controller and an actuator.
23. A method of depositing a layer on a surface of a substrate, comprising:
- providing a target that has a surface that contacts a processing region;
- providing a magnetron section that is magnetically coupled to the processing region through the target;
- moving the magnetron section in a direction that is generally parallel to the surface of the target by use of an actuator;
- depositing a conductive layer on a surface of a substrate that is positioned in the processing region; and
- adjusting the position of the magnetron section in a direction generally perpendicular to the surface of the target while the magnetron is moving in a direction that is generally parallel to the surface of the target to improve the deposition uniformity across the surface of the substrate.
24. The method of claim 23, further comprising:
- providing a second magnetron section that is magnetically coupled to the processing region through the target;
- moving the second magnetron section in a direction that is generally parallel to the surface of the target by use of the actuator; and
- adjusting the position of the second magnetron section in a direction generally perpendicular to the surface of the target while the second magnetron is moving in a direction that is generally parallel to the surface of the target to improve the deposition uniformity across the surface of the substrate.
25. The method of claim 23, further comprising:
- providing a second magnetron section that is magnetically coupled to the processing region through the target;
- moving the second magnetron section in a direction that is generally parallel to the surface of the target by use of a second actuator; and
- adjusting the position of the second magnetron section in a direction generally perpendicular to the surface of the target while the second magnetron is moving in a direction that is generally parallel to the surface of the target to improve the deposition uniformity across the surface of the substrate.
26. The method of claim 23, wherein the step of adjusting the position the magnetron section is continually controlled by use of a controller and an actuator.
Type: Application
Filed: Nov 17, 2005
Publication Date: Mar 8, 2007
Inventors: Hienminh Le (San Jose, CA), Akihiro Hosokawa (Cupertino, CA)
Application Number: 11/282,798
International Classification: C23C 14/32 (20060101); C23C 14/00 (20060101);