Systems and methods for ion source temperature control using symmetrical or asymmetrical application of forces

Abstract

An ion source is disclosed in which the compressive force applied to the faceplate on two sides of the extraction opening can be individually varied. By modifying the compressive force between the faceplate and the arc chamber, and by modifying the thermal contact resistance between the two components, temperature control of the ion source can be enabled. This allows for more precise control of the temperature of the faceplate, and more specifically, the temperature profile across the entire faceplate, through precise control of the thermal contact gradient along the length of the faceplate. The ion implantation system includes two adjustable tension systems, each containing an actuator. A controller is used to provide command signals to each adjustable tension system. In some embodiments, feedback signals are generated by each adjustable tension system, representing the torque or force acting on the actuator.

Description

Technical Field

[0001] This application claims priority to U.S. Patent Application No. 18 / 143,684, filed May 05, 2023, the disclosure of which is hereby incorporated by reference in its entirety.

[0002] Embodiments of the present disclosure relate to systems and methods for controlling the temperature of an ion source by applying a force to a faceplate.

Background Art

[0003] The manufacture of semiconductor devices involves multiple distinct and complex processes. One such process may utilize an ion beam that can be extracted from an ion source. In an ion source, a supply gas is excited to form ions. These ions are then extracted from the ion source through an extraction aperture disposed on a faceplate. The ions are manipulated downstream by various components including electrodes, acceleration and deceleration stages, and mass analyzers.

[0004] One such ion source is a cathode ion source that is indirectly heated. An indirectly heated cathode (IHC) ion source operates by supplying current to a filament disposed behind the cathode. The filament emits thermionic electrons that are accelerated towards the cathode through an applied potential, heating the cathode and emitting electrons into the arc chamber of the ion source. The cathode is disposed at one end of the arc chamber. A repeller may be disposed at the end of the arc chamber opposite the cathode. The cathode and repeller may be biased to repel electrons and return them towards the center of the arc chamber. In some embodiments, a magnetic field is used to further confine electrons within the arc chamber. A plurality of sides are used to connect the two ends of the arc chamber.

[0005] The extraction opening is located along one of these sides, called the faceplate. The extraction opening is located near the center of the arc chamber, and ions generated within the arc chamber can be extracted through this center.

[0006] In certain situations, material can accumulate on the inner surface of the faceplate, potentially leading to a non-uniform ion beam. This material can be generated by the condensation of the supply gas species on cooler surfaces. Alternatively, material deposition on the inner surface of the faceplate may preferentially occur on warmer surfaces, depending on the supply gas species, in some systems. The deposition rate may be related to the faceplate temperature. In many IHC ion sources, the side of the faceplate closest to the cathode may be warmer than the side furthest from the cathode due to its proximity to the thermal radiation cathode. Therefore, material deposition is non-uniform, which can lead to a non-uniform extracted ion beam.

[0007] Therefore, a system that controls the temperature of the faceplate to reduce material buildup would be beneficial. [Overview of the Initiative]

[0008] An ion source is disclosed in which the compressive force applied to the faceplate on two sides of the extraction opening can be individually varied. By modifying the compressive force between the faceplate and the arc chamber, and by modifying the thermal contact resistance between the two components, temperature control of the ion source can be enabled. This allows for more precise control of the temperature of the faceplate, and more specifically, the temperature profile across the entire faceplate, through precise control of the thermal contact gradient along the length of the faceplate. The ion implantation system includes two adjustable tension systems, each containing an actuator. A controller is used to provide command signals to each adjustable tension system. In some embodiments, a feedback signal is generated by each adjustable tension system, representing the torque or force received by the actuator. This feedback signal may be used to adjust the command signals supplied to each adjustable tension system.

[0009] According to one embodiment, an ion implantation system is disclosed. The ion implantation system comprises an ion source including an arc chamber having a plurality of chamber walls and a first end and a second end, and a faceplate having extraction openings positioned on top of the plurality of chamber walls; a source housing on which the arc chamber is positioned; a first fastener and a second fastener for pressing the faceplate against the top of the plurality of chamber walls of the arc chamber, wherein the first fastener is positioned near the first end and the second fastener is positioned near the second end; a first adjustable tension system communicating with the first fastener to apply tension to the first fastener and a second adjustable tension system communicating with the second fastener to apply tension to the second fastener; and a controller communicating with the first adjustable tension system and the second adjustable tension system, configured to apply different tensions to each fastener. In some embodiments, the tension applied to the first end adjacent to the cathode in the arc chamber is greater than the tension applied to the second end to raise the temperature of the faceplate. In some embodiments, the tension applied to the first end adjacent to the cathode in the arc chamber is less than the tension applied to the second end to lower the temperature of the faceplate. In some embodiments, a controller receives an input and, based on the input, determines a desired tension for a first adjustable tension system and a desired tension for a second adjustable tension system. In certain embodiments, the input is the type of supply gas used, a desired temperature, or a desired force. In some embodiments, each fastener includes a strap, the strap having an engaging portion that rests on the faceplate and two mounting portions, the two mounting portions being connected to their respective adjustable tension systems.

[0010] An ion implantation system is disclosed according to other embodiments. Ion implantation system: an ion source including an arc chamber having a first end and a second end and a faceplate having extraction openings positioned on top of the plurality of chamber walls; a source housing on which the arc chamber is positioned; a first fastener and a second fastener for pressing the faceplate against the top of the plurality of chamber walls, the first fastener positioned near the first end and the second fastener positioned near the second end; a first adjustable tension system communicating with the first fastener to apply tension to the first fastener, and a second adjustable tension system communicating with the second fastener to apply tension to the second fastener, each adjustable tension system comprising an actuator and a tension system, the tension system including a yoke, a retaining bracket, and a spring between the yoke and the retaining bracket to be attached to the respective fastener, the actuator including a shaft, the movement of the shaft changing the distance between the retaining bracket and the yoke. In some embodiments, the source housing comprises a cylindrical housing body with a flat area formed on the housing body for mounting the tension system. In some embodiments, the source housing comprises a flange positioned near the arc chamber, the flange positioned between the arc chamber and the tension system, and the flange comprises a slot through which a fastener passes. In some embodiments, the actuator comprises a linear actuator, the shaft fixed to a retaining bracket. In some embodiments, each adjustable tension system further comprises a ball screw passing through the inside of a spring and rotatably coupled to a retaining bracket, the actuator comprises a rotary motor and a gear positioned at the distal end of the shaft, the gear engaging with a ball screw gear that rotates the ball screw. In certain embodiments, the source housing has a hollow interior, the tension system is mounted on the outer wall of the source housing, and the actuator is located inside the source housing.In certain embodiments, a slot is located within the source housing that connects a hollow interior to the outer wall, and a gear extends through the slot to connect the actuator to the tension system. In some embodiments, the arc chamber and source housing are located within a vacuum chamber, the tension system is mounted on the outer wall of the source housing, and the actuator is located outside the vacuum chamber so that its shaft enters the vacuum chamber from the atmospheric environment.

[0011] An ion implantation system is disclosed according to another embodiment. The ion implantation system comprises an ion source including an arc chamber having a plurality of chamber walls and a first end and a second end, and a faceplate having extraction openings positioned on top of the plurality of chamber walls; a source housing on which the arc chamber is positioned; a first fastener positioned near the first end and a second fastener positioned near the second end; a first adjustable tension system communicating with the first fastener to apply tension to the first fastener, and a second adjustable tension system communicating with the second fastener to apply tension to the second fastener, each adjustable tension system including an actuator; and a controller communicating with the first adjustable tension system and the second adjustable tension system to supply a desired tension to each adjustable tension system, supplying a command signal to each adjustable tension system, receiving a feedback signal from each adjustable tension system, the feedback signal indicating the actual tension each adjustable tension system receives. In some embodiments, the controller updates a command signal for each adjustable tension system based on its respective feedback signal. In some embodiments, the controller updates the command signal multiple times. In certain embodiments, the controller updates the command signal at least once per minute.

[0012] To better understand this disclosure, refer to the attached drawings. These drawings are incorporated herein by reference. [Brief explanation of the drawing]

[0013] [Figure 1A] This is a diagram of an ion source according to one embodiment. [Figure 1B] This is a diagram of an ion source according to the second embodiment. [Figure 2] Figures 1A and 1B show side views of the inside of the ion source. [Figure 3] This is a block diagram of the control system. [Figure 4] This shows the operation of a control system according to one embodiment. [Figure 5] An ion source having an adjustable tension system according to the first embodiment is shown. [Figure 6A-C] This shows an adjustable tension system used in various embodiments. [Figure 7] An ion source having an adjustable tension system according to a second embodiment is shown. [Figure 8] An ion source having an adjustable tension system according to a third embodiment is shown. [Figure 9] Source housings that may be used with each of the embodiments are shown. [Figure 10A-10C] This shows a theoretical temperature gradient of the faceplate with various compressive forces applied to each edge of the faceplate. [Modes for carrying out the invention]

[0014] As mentioned above, the temperature of the faceplate within the IHC ion source can affect the rate of material deposition on the inner surface of the faceplate. A thermal gradient across the operating faceplate can lead to uneven deposition across the faceplate and extraction openings, resulting in uneven extraction opening dimensions and thus uneven ion extraction from the IHC ion source. This deposition can contribute to ion beam inhomogeneity and increased maintenance.

[0015] Figure 1A shows an ion source having temperature control of a faceplate according to one embodiment. The ion source 10 includes a plurality of chamber walls 11 defining an arc chamber 200. A faceplate 40 having extraction openings 41 may be positioned in contact with the upper surface of the chamber walls 11. The faceplate 40 may be a single component or may consist of multiple components. For example, in one embodiment, the faceplate 40 includes a faceplate insert positioned below an outer side plate and helping to define the extraction openings 41. Thus, the term “faceplate” as used in this disclosure refers to any component or component that constitutes a structure including extraction openings from which ions are removed. Within the arc chamber 200, there may be a mechanism for generating ions. For example, in one embodiment, an indirectly heated cathode (IHC) may be positioned within the arc chamber.

[0016] The faceplate 40 is secured to the source housing 30 using a number of fasteners, which in this embodiment may be two straps 50. The source housing 30 may include a flange 31 having holes or slots 32 through which the straps 50 pass. The straps 50 are held in place using an adjustable tension system 100. The arc chamber 200 may be attached to the source housing 30. In certain embodiments, the source housing 30 may be temperature-controlled. For example, the source housing 30 may be attached to a heat sink or may be the heat sink itself. Thus, the chamber wall 11 is in direct thermal contact with the source housing 30. This may help to cool the chamber wall 11. The source housing 30 may include a lower flange 33. This lower flange 33 can isolate the vacuum chamber where the ion source 10 is located from the atmospheric environment. Thus, components located below the lower flange 33 may be in the atmospheric environment, while components above the lower flange 33 are in the vacuum chamber.

[0017] The strap 50 may be formed to have a rounded rectangular cross-section. The cross-section of the strap 50 has a width and a thickness, the width may be greater than the thickness. The width of the strap 50 may be between 0.25 inches and 1 inch, while the thickness may be between 1 / 16 and 1 / 4 inch. The strap 50 includes three straight sections separated by rounded portions 51. The rounded portions 51 may include curved sections having a radius of curvature. The radius of curvature of the rounded portions may be between 0.25 inches and 1.00 inches. In some embodiments, the bend is a 90° bend, while in other embodiments, the bend may be between 45° and 135°. Between the rounded portions 51 are engaging portions 52. As shown in Figure 1A, the engaging portions 52 of the strap 50 are the portions that abut against the outer surface of the faceplate 40. In some embodiments, the length of the engaging portion 52 is slightly longer than the width of the faceplate 40 so that the engaging portion 52 contacts the entire width of the faceplate 40. For example, the engaging portion 52 of the strap 50 may be 1 to 6 inches, but other dimensions are possible. On the opposite side of each rounded portion 51 is a mounting portion 53. Each mounting portion 53 may have a length greater than the height of the arc chamber 200. For example, the mounting portion 53 may have a length of 4 to 10 inches, but other dimensions are possible. As is best seen in Figure 1A, the mounting portion 53 of the strap 50 may pass through a slot 32 or opening in the flange 31. A hole may be located near the distal end of each mounting portion 53. This hole is used to attach the strap 50 to the adjustable tension system 100. A first fastener is located near the first end 201 of the arc chamber 200 (see Figure 2), and a second fastener is located near the second end 202 of the arc chamber 200 (see Figure 2). There is a first adjustable tension system 100 associated with the cathode side (i.e., the first end 201) of the faceplate 40, and a second adjustable tension system 100 associated with the repeller side (i.e., the second end 202) of the faceplate 40.

[0018] The adjustable tension system 100 includes a tension system 110 that may include a spring and an actuator 120 (see FIG. 3). The actuator 120 is used to change the length of the spring, and as a result, the compressive force applied to the faceplate 40 by the strap 50 changes. The tension system 110 is arranged such that the flange 31 is positioned between the arc chamber 200 and the tension system 110.

[0019] The adjustable tension system 100 may communicate with a controller 70. The controller 70 includes a processing unit 71 and an associated memory device 72 (see FIG. 3). This memory device 72 includes instructions that, when executed by the processing unit 71, enable the controller 70 to perform the functions described herein. The memory device 72 may be a non-volatile memory, such as a flash ROM, an electrically erasable ROM, or other suitable device. The processing unit 71 may be a general-purpose computer, a dedicated computer, a microcontroller, or another type of electrical circuit. The controller 70 may output one or more electrical signals to the actuator 120, as will be described in more detail below.

[0020] FIG. 1B shows an ion source having temperature control of the faceplate 40 according to a second embodiment. The same reference numerals are given to the same components. In this embodiment, each fastener is a set of two hooks 55 instead of a strap. Each hook may include a rounded end disposed within a recess on the upper surface of the faceplate 40. The distal end of each hook may include another rounded end for attachment to the adjustable tension system 100. The remainder of the ion source is the same as that shown in FIG. 1A.

[0021] FIG. 2 shows a side view of the electronic device and the interior of the ion source 10 according to one embodiment. In this embodiment, the ion source 10 includes an arc chamber 200 having two opposing ends and chamber walls 11 connected to these ends. The arc chamber 200 also includes a bottom wall and a face plate 40. The chamber walls 11 may be made of an electrically and thermally conductive material and may be in electrical contact with each other. The cathode 210 is disposed within the arc chamber 200 at the first end 201 of the arc chamber 200. The filament 260 is disposed behind the cathode 210. The filament 260 communicates with a filament power supply 265. The filament power supply 265 is configured to pass a current through the filament 260 such that the filament 260 emits thermionic electrons. A cathode bias power supply 215 biases the filament 260 negatively with respect to the cathode 210 so that these thermionic electrons are accelerated from the filament 260 toward the cathode 210, and when these thermionic electrons hit the back surface of the cathode 210, the cathode 210 is heated. The cathode bias power supply 215 may bias the filament 260 to have a voltage, for example, between -200V and -1500V relative to the voltage of the cathode 210. Then, the cathode 210 emits thermionic electrons on its front surface into the arc chamber 200.

[0022] Thereby, the filament power supply 265 supplies a current to the filament 260. The cathode bias power supply 215 biases the filament 260 to be negative relative to the cathode 210, so that electrons are attracted from the filament 260 toward the cathode 210. Further, a cathode power supply 270 can be used to electrically bias the cathode 210 with respect to the arc chamber 200. Due to the power applied to the cathode 210 and the emission of electrons, the arc chamber 200 can become warmer near the cathode 210. This includes a part of the face plate 40 located near the cathode 210.

[0023] In this embodiment, the repeller 220 is located within the arc chamber 200 on the second end 202 of the arc chamber 200 opposite the cathode 210. The repeller 220 can communicate with a repeller power supply 225. As the name suggests, the repeller 220 plays a role in repelling electrons emitted from the cathode 210 toward the center of the arc chamber 200. For example, the repeller 220 may be biased with a negative voltage relative to the arc chamber 200 to repel electrons. For example, the repeller power supply 225 may have an output in the range of 0 to -150V, but other voltages may be used. In certain embodiments, the repeller 220 is biased between 0 and -150V relative to the arc chamber 200. In other embodiments, the cathode power supply 270 is also used to supply voltage to the repeller 220. In other embodiments, the repeller 220 may be electrically grounded or floating. In other embodiments, the repeller 220 may be omitted.

[0024] During operation, gas is supplied to the arc chamber 200. Thermionic electrons emitted from the cathode 210 cause the gas to form a plasma 250. Ions from this plasma 250 are then extracted through extraction openings 41 in the faceplate 40. The ions are then manipulated to form an ion beam directed toward the workpiece. An extraction electrode 280 is positioned outside the arc chamber 200 and near the extraction openings 41. The extraction electrode 280 is biased with a voltage different from that of the arc chamber 200 to attract ions from inside the arc chamber 200 through the extraction openings 41.

[0025] It should be noted that other mechanisms for generating ions may also be used. These other mechanisms include, but are not limited to, Vernas ion sources, RF antennas, and capacitive coupling sources.

[0026] Figure 3 shows a block diagram of the control system used to control the adjustable tension system 100. The controller 70 can communicate with an input device 75, such as a keyboard, touchscreen, or other device. The controller 70 also communicates with two adjustable tension systems 100. As described above, the first adjustable tension system is used to control the compressive force applied to the faceplate 40 near the first end 201 closest to the cathode 210, and the second adjustable tension system is used to control the compressive force applied to the faceplate 40 near the second end 202 (if present) opposite the first end 201.

[0027] Each adjustable tension system 100 includes an actuator 120, which may be a rotary motor or a linear actuator, as will be described in more detail below. Each actuator 120 receives a command signal 121 from a controller 70. The command signal 121 may be an analog signal, a time-varying analog signal having amplitude, period, and duty cycle, or a digital signal. The command signal 121 to the actuator 120 determines the momentum (either rotational or linear motion) that the actuator 120 generates. In some embodiments, each actuator 120 further includes a feedback signal 122, which may represent the torque (in the case of a rotary actuator) or force (in the case of a linear actuator) that the actuator 120 is actually experiencing. Thus, the feedback signal 122 indicates the tension or compressive force applied to the fastener. This feedback signal 122 is provided to the controller 70, which can use this value to further adjust the command signal 121 to the actuator 120. As described above, the adjustable tension system 100 also typically includes a tension system 110 which includes at least one spring. In this way, the two adjustable tension systems 100 may be controlled independently, and the controller 70 may issue different command signals 121 to each adjustable tension system 100. Thus, the compressive force applied by the first fastener near the first end 201 may be less than, greater than, or equal to the compressive force applied by the second fastener near the second end 202 of the arc chamber 200.

[0028] Figure 4 illustrates the operation of the control system shown in Figure 3. First, as shown in box 400, the controller 70 receives input from an operator or the like via an input device 75. This input may be a desired force applied to the two ends of the IHC ion source to compress each end of the faceplate 40 into the chamber wall 11 of the arc chamber. In other embodiments, the input may be a recipe, which is a list of parameters related to the operation of the ion source 10, such as a desired temperature of the faceplate 40, the type of supply gas introduced, the tension applied to the fasteners, or a recipe. As shown in box 410, based on this input, the controller 70 determines a desired tension for the fastener associated with a first adjustable tension system (i.e., the first end 201) and the fastener associated with a second adjustable tension system (i.e., the second end 202). The tension on the fasteners is pulled down on the faceplate 40 and directly converted into applying a compressive force of equal magnitude between the faceplate 40 and the arc chamber 200. The desired tensile or compressive force can be determined using a lookup table stored in the memory device 72 or by an expression executed by the processing unit 71. As described above, the desired fastener tension may differ between the two adjustable tension systems. The controller 70 then provides the desired tension to each adjustable tension system 100 via a command signal 121, as shown in box 420. In certain embodiments, the controller 70 then receives a feedback signal 122 from the actuator 120, as shown in box 430. This feedback signal 122 indicates the torque or force that the actuator is actually experiencing. Based on this feedback, the controller 70 then adjusts the command signal 121 provided to the actuator 120 so that the feedback signal is equal to the desired tension, as shown in box 440. In certain embodiments, the control system repeats boxes 430-440 throughout the operation of the IHC ion source. For example, over time, the material in the fastener assembly may soften or relax, reducing the compressive force on the faceplate 40.This relaxation can be compensated for by continuously monitoring the feedback signal 122 and adjusting the command signal 121, so that the compression force does not change over time. In some embodiments, boxes 430-440 are executed multiple times. In some embodiments, these boxes may be executed at regular intervals. In some embodiments, boxes 430-440 may be executed every 1-5 milliseconds. In other embodiments, these boxes may be executed more frequently, such as every second or more. Thus, the rate of monitoring is not limited by this disclosure and may be any appropriate period, such as every millisecond. In certain embodiments, boxes 430-440 may be executed at least once per minute. In some embodiments, boxes 430-440 may be executed at least once per hour.

[0029] Figure 5 shows a first embodiment of the ion implantation system including the control system described above. A strap 50 is shown, but it should be understood that the fastener may be a hook 55. In this embodiment, each adjustable tension system 100 includes an actuator 120, which is a rotary motor 500. In this embodiment, the source housing 30 may have a hollow interior. The rotary motor 500 is located in a cavity within the source housing 30, which is placed in a vacuum chamber. The rotary motor 500 is coupled to a shaft 510 to which a gear 520 is attached. A slot 35 (see Figure 9) is located in the wall of the source housing 30, which allows the gear 520 from the rotary motor 500 to pass through the wall of the source housing 30 and engage with the tension system 110. The tension system 110 is mounted on the outer wall of the source housing 30. The tension system 110 includes a yoke 610 used to connect a fastener to the tension system 110. Figure 5 shows a rotary motor 500 located in a vacuum chamber, but other embodiments are possible. For example, the rotary motor 500 may be located outside the vacuum chamber, for example, in the atmospheric environment opposite the lower flange 33 of the source housing 30. A vacuum flange (not shown) may be used to allow the shaft 510 to pass from the atmospheric environment into the vacuum chamber.

[0030] Figures 6A to 6C show the tension system 110 in more detail. In this embodiment, the tension system 110 includes an upper mounting bracket 620 and a lower mounting bracket 625, both fixed to the outer wall of the source housing 30. The yoke 610, which is attached to the fastener, includes two arms 611 and a central portion 612. The central portion 612 is inserted between the upper mounting bracket 620 and the lower mounting bracket 625 and includes a hole. The retaining bracket 640 is used to compress the spring 650 so that the spring 650 is positioned between the lower surface of the retaining bracket 640 and the upper surface of the central portion 612 of the yoke 610. The retaining bracket 640 may include one or more guide rails 645 that extend through the central portion 612 to the lower mounting bracket 625. The guide rails 645 may be used to ensure stable uniaxial motion of the retaining bracket 640. A ball screw 630 is inserted through an opening in the lower mounting bracket 625. The shaft of the ball screw 630 passes through a hole in the central portion 612 of the yoke 610 and is positioned inside the spring 650. The ball screw 630 passes through an opening in the retaining bracket 640. A threaded fastener 670, such as a nut or other suitable component, is then screwed onto the end of the ball screw 630 and secured to the upper surface of the retaining bracket 640. One end of the ball screw 630, such as the end closest to the lower mounting bracket 625, includes a ball screw gear 631 that engages with the gear 520. The spring 650 applies a downward force to the central portion 612 of the yoke 610. This force is related to the distance between the central portion 612 and the lower surface of the retaining bracket 640. Figure 6B shows the tension system 110 in a position having the maximum spring length and minimum force applied by the spring 650. The retaining bracket 640 is in its uppermost position, allowing for the maximum length of the spring 650. Figure 6C shows the tension system after the ball screw 630 has rotated multiple times to bring the retaining bracket 640 closer to the lower mounting bracket 625. The length of the spring 650 is shorter, creating a greater downward force in the central portion 612 of the yoke 610. Thus, when the rotary motor 500 is activated during operation, it causes the gear 520 connected to the ball screw gear 631 to rotate.The rotation of the ball screw gear 631 causes linear motion of the retaining bracket 640, which changes the compression of the spring 650, and subsequently determines the compressive force applied to the faceplate 40 by the fastener. The figure shows the ball screw gear 631 located near the lower mounting bracket 625, but it should be noted that the configuration may be changed so that the ball screw gear is located near the upper mounting bracket 620.

[0031] Figure 7 shows a second embodiment of the adjustable tension system. In this embodiment, the tension system 110 is shown in Figures 6A to 6C. However, in this embodiment, the shaft 510 and gear 520 are located outside the source housing 30. The shaft 510 and gear 520 are located inside the vacuum chamber. In certain embodiments, the rotary motor 500 is located outside the vacuum chamber, for example, in the atmospheric environment opposite the lower flange 33 of the source housing 30. A vacuum flange 700 may be used to allow the shaft 510 to pass from the atmospheric environment into the vacuum chamber. In other embodiments, the rotary motor 500 may be located inside the vacuum chamber. This configuration may allow for additional space within the cavity in the source housing 30 to accommodate the location of other components.

[0032] Figure 8 shows a third embodiment of the ion source. In this embodiment, the actuator 120 is a linear actuator 800 having a linearly moving shaft 810. The shaft 810 passes through the lower mounting bracket 625, a hole in the central portion 612 of the yoke 610, and the inside of the spring 650, rather than being a ball screw. The shaft 810 is fixed to the retaining bracket 640. The rest of the tension system 110 is similar to that shown in Figures 6A to 6C. The linear actuator 800 may be placed in a vacuum chamber, as shown in Figure 8. In another embodiment, the linear actuator 800 is placed in an atmospheric environment, similar to the configuration in Figure 7. In this embodiment, the shaft 810 passes through the lower flange 33 of the source housing 30 and extends to the retaining bracket 640. In this embodiment, the movement of the shaft 810 directly causes the linear movement of the retaining bracket 640 and the compression of the spring 650.

[0033] Of course, the tension system 110 may be implemented in other ways, and is not limited to those shown herein.

[0034] Figure 9 shows the source housing 30 in more detail. This source housing 30 may be used in any of the embodiments described above. As described above, the source housing 30 has a flange 31 located on or near the top surface. The flange 31 has a number of openings or slots 32 through which fasteners pass. In certain embodiments, there may be a total of four slots 32. The bottom of the source housing 30 may include a lower flange 33. The source housing 30 includes a housing body 34 defined as the region between the flange 31 and the lower flange 33. In certain embodiments, the interior of the housing body 34 may be hollow and may contain components such as actuators (shown in Figure 5). The outside of the housing body 34 may be cylindrical. Two regions located on opposite sides of the housing body 34 may be machined to form a flat surface 36. The flat surface 36 may have a width ranging from 1 to 3 inches and a height ranging from 2 to 5 inches, but other dimensions are possible. The flat surface 36 creates a place where each tension system 110 may be mounted. This flat surface 36 can be used to mount a tension system 110 in any of the embodiments shown in Figures 5, 7, and 8. Within each flat surface 36, a slot 35 may be provided that passes from the inside to the outside of the housing body 34. The slot 35 allows couplings, such as gears, to pass from the inside to the outside of the housing body 34. This is useful in the embodiment shown in Figure 5. Note that in other embodiments, the slot 35 may not be present.

[0035] The embodiments described above in this application may have many advantages. In one system design case, the cathode 210 is heated to a temperature that conducts heat from the chamber wall 11 to the faceplate 40. A temperature profile of the faceplate 40 with equal moderate compressive force at each end of the faceplate is shown in Figure 10A. Note that approximately half of the extraction opening 41 is in the medium-high temperature range, and the other half of the extraction opening is in the medium-low temperature range. Under these force conditions, the temperature difference between the high-temperature and low-temperature portions of the faceplate may exceed 200°C. Thus, each temperature range may represent more than 50°C. In Figure 10B, the compressive force increases at the second end 202 of the faceplate 40 and decreases at the first end 201 of the faceplate 40. The resulting thermal resistance gradient between the faceplate 40 and the chamber wall 11 reduces heat transfer from the first end 201 to the faceplate 40 and also increases the ability of the second end 202 of the arc chamber 200 to function as a heat sink. As a result, the temperature of the extraction opening 41 decreases, so that approximately half of the extraction opening 41 is in the low-temperature range and the remaining part of the extraction opening is in the medium-low temperature range. Therefore, the overall temperature of the faceplate 40 can be lowered by having a compressive force at the first end 201 that is smaller than the compressive force at the second end 202. In Figure 10C, the compressive force increases on the cathode side of the faceplate 40 (i.e., the first end 201) and decreases on the repeller side of the faceplate 40 (i.e., the second end 202). The resulting thermal contact gradient conducts more heat from the first end 201 to the faceplate 40, and also reduces the ability of the second end 202 of the arc chamber 200 to function as a heat sink. As a result, the entire extraction opening 41 is in the high-temperature range. Therefore, the overall temperature of the faceplate 40 can be raised by having a compressive force at the first end 201 that is larger than the compressive force at the second end 202.

[0036] This disclosure should not be limited in scope by the specific embodiments described herein. In fact, a person skilled in the art will see from the above description and accompanying drawings that, in addition to the embodiments and modifications to this disclosure, a variety of other embodiments and modifications not described herein will be obvious. Thus, such other embodiments and modifications are also intended to be within the scope of this disclosure. Furthermore, while this disclosure has been described herein in relation to a specific implementation in a specific environment for a specific purpose, a person skilled in the art will recognize that the usefulness of this disclosure is not limited thereto, and that this disclosure can be beneficially implemented in any number of environments for any number of purposes. Accordingly, the claims described below should be interpreted in light of the entire scope and essence of this disclosure as described herein.

Claims

1. An ion implantation system, It is an ion source, An arc chamber comprising multiple chamber walls and having a first end and a second end, and A faceplate having extraction openings is positioned on the upper part of the plurality of chamber walls. An ion source containing the arc chamber, and a source housing on which the arc chamber is located, A first fastener and a second fastener for pressing the faceplate against the upper part of the plurality of chamber walls of the arc chamber, wherein the first fastener is positioned near the first end and the second fastener is positioned near the second end, A first adjustable tension system that communicates with the first fastener to apply tension to the first fastener, and a second adjustable tension system that communicates with the second fastener to apply tension to the second fastener, A controller communicating with the first adjustable tension system and the second adjustable tension system, the controller configured to apply different tensions to each fastener. An ion implantation system equipped with the following features.

2. The ion implantation system according to claim 1, wherein the tension applied to the first end adjacent to the cathode in the arc chamber is greater than the tension applied to the second end to raise the temperature of the faceplate.

3. The ion implantation system according to claim 1, wherein the tension applied to the first end adjacent to the cathode in the arc chamber is less than the tension applied to the second end to lower the temperature of the faceplate.

4. The ion implantation system according to claim 1, wherein the controller receives an input and determines, based on the input, a desired tension for the first adjustable tension system and a desired tension for the second adjustable tension system.

5. The ion implantation system according to claim 4, wherein the input is the type of supply gas being used, a desired temperature, or a desired force.

6. The ion implantation system according to claim 1, wherein each fastener includes a strap, the strap includes an engaging portion that rests on the faceplate and two attachment portions, the two attachment portions being connected to their respective adjustable tension systems.

7. An ion implantation system, It is an ion source, An arc chamber comprising multiple chamber walls and having a first end and a second end, and A faceplate having an extraction opening is positioned on the upper part of the plurality of chamber walls. An ion source containing, The source housing, on which the arc chamber is positioned, A first fastener and a second fastener for pressing the faceplate against the upper part of the plurality of chamber walls, wherein the first fastener is positioned near the first end and the second fastener is positioned near the second end, A first adjustable tension system for communicating with the first fastener to apply tension to the first fastener, and a second adjustable tension system for communicating with the second fastener to apply tension to the second fastener, wherein each adjustable tension system includes an actuator and a tension system, the tension system including a yoke to be attached to the respective fastener, a retaining bracket, and a spring positioned between the yoke and the retaining bracket, the actuator including a shaft, the movement of which changes the distance between the retaining bracket and the yoke, and the first adjustable tension system and the second adjustable tension system An ion implantation system equipped with the following features.

8. The ion implantation system according to claim 7, wherein the source housing includes a housing body having a cylindrical shape, and a flat area is formed on the housing body for mounting the tension system.

9. The ion implantation system according to claim 7, wherein the source housing includes a flange positioned adjacent to the arc chamber, the flange being positioned between the arc chamber and the tension system, and the flange including a slot through which the fastener passes.

10. The ion implantation system according to claim 7, wherein the actuator includes a linear actuator and the shaft is fixed to the retaining bracket.

11. The ion implantation system according to claim 7, wherein each adjustable tension system further includes a ball screw that passes through the inside of the spring and is rotatably connected to the retaining bracket, and the actuator includes a rotary motor and a gear located at the distal end of the shaft, the gear engaging with a ball screw gear that rotates the ball screw.

12. The ion implantation system according to claim 11, wherein the source housing has a hollow interior, the tension system is attached to the outer wall of the source housing, and the actuator is located inside the source housing.

13. The ion implantation system according to claim 12, wherein a slot is located within the source housing and connects the hollow interior to the outer wall, and the gear extends through the slot and connects the actuator to the tension system.

14. The ion implantation system according to claim 7, wherein the arc chamber and the source housing are located within a vacuum chamber, the tension system is attached to the outer wall of the source housing, and the actuator is located outside the vacuum chamber such that the shaft passes from the atmospheric environment into the vacuum chamber.

15. An ion implantation system, It is an ion source, An arc chamber comprising multiple chamber walls and having a first end and a second end, and A faceplate having extraction openings is positioned on the upper part of the plurality of chamber walls. An ion source containing, The source housing, on which the arc chamber is positioned, A first fastener located near the first end and a second fastener located near the second end, A first adjustable tension system that communicates with the first fastener to apply tension to the first fastener, and a second adjustable tension system that communicates with the second fastener to apply tension to the second fastener, wherein each adjustable tension system includes an actuator, A controller that communicates with the first adjustable tension system and the second adjustable tension system, the controller supplying a desired tension to each adjustable tension system, supplying command signals to each adjustable tension system, receiving feedback signals from each adjustable tension system, and the feedback signals indicating the actual tension each adjustable tension system receives. An ion implantation system equipped with the following features.

16. The ion implantation system according to claim 15, wherein the controller updates the command signals to each adjustable tension system based on the respective feedback signals.

17. The ion implantation system according to claim 16, wherein the controller updates the command signal multiple times.

18. The ion implantation system according to claim 17, wherein the controller updates the command signal at least once every minute.

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