Rotating disk having an electrostatic clamp platen for ion implantation

Abstract

A system is disclosed that includes a rotating disk, including a semiconductor processing system such as a high energy implantation system. The semiconductor processing system generates a spot ion beam that is directed to a number of workpieces disposed on the rotating disk. The rotating disk includes a rotating central hub having a number of platens. The platens may extend outwardly from the central hub, and the workpieces are electrostatically clamped to the platens. The platens may also rotate. The central hub also controls the rotation of each of the platens about an axis orthogonal to the axis of rotation of the central hub. In this manner, variable angle implants may be performed. Additionally, this allows the workpiece to be mounted while in a horizontal orientation.

Description

Technical Field

[0001] This application claims the benefit of U.S. Patent Application No. 17 / 547,623, filed on December 10, 2021, the disclosure of which is hereby incorporated by reference in its entirety.

[0002] Embodiments of the present disclosure are directed to systems and methods for holding, handling, and processing workpieces using a rotating disk.

Background Art

[0003] High energy implantation systems are used to fabricate semiconductor devices having deep implantation regions. Certain types of devices are referred to as insulated gate bipolar transistors (IGBTs). IGBTs combine the concepts of bipolar transistors and MOSFETs to realize improved power devices. The emitter and gate are disposed on one side of the device, and the collector is disposed on a second side opposite the device. The emitter communicates with a highly doped p-type region disposed directly below the emitter. On both sides of the highly doped p-type region are highly doped n-type regions, each of which communicates with the gate. Below the highly doped p-type region is a lightly doped p-type region. On the opposite side of the device is a second highly doped p-type region that communicates with the collector. Finally, between the second highly doped p-type region and the lightly doped p-type region is a lightly doped n-type drift layer.

[0004] In conventional IGBT devices, the thickness of the lightly doped n-type drift layer is determined based on the need to maintain an electric field. As the rated power of these devices increases, the overall thickness of the device also increases.

[0005] These devices can be fabricated using high-energy implantation. However, one drawback of these devices can be the angular spread. Conventionally, in these implantation systems, a spot beam is generated. The spot beam is then electrostatically scanned to generate a ribbon ion beam that impinges on the workpiece. However, the non-uniformity of the angular spread can be exacerbated by the electrostatic scanner.

[0006] Accordingly, it would be beneficial to have a semiconductor processing system that can perform high-energy implantation without the drawbacks of current technology. In particular, it would be beneficial to have a system that performs high-energy implantation on a batch of electrostatically clamped workpieces. SUMMARY OF THE INVENTION

[0007] A system comprising a rotating disk is disclosed. The system includes a semiconductor processing system such as a high-energy implantation system. The semiconductor processing system generates a spot ion beam. The spot ion beam is directed at a plurality of workpieces disposed on the rotating disk. The rotating disk includes a rotating central hub having a plurality of platens. The plurality of platens may extend outwardly from the central hub, and the workpieces are electrostatically clamped to the platens. The plurality of platens can also rotate. The central hub also controls the rotation of each of the platens about an axis orthogonal to the axis of rotation of the central hub. In this way, variable angle implantation can be performed. Further, this allows the workpieces to be attached while the workpieces are in a horizontal orientation.

[0008] According to one embodiment, a rotating disk for processing a plurality of workpieces is disclosed. The rotating disk includes a central hub adapted to rotate about a central axis, a plurality of spokes radially extending outwardly from the central hub, each of the plurality of spokes being adapted to rotate about a respective axis radially extending from the central hub, a platen disposed at a distal end of each of the plurality of spokes, each platen including a plurality of electrodes and being configured to electrostatically clamp a respective workpiece, and a plurality of rotating motors disposed within the central hub, each rotating motor communicating with a respective one of the plurality of spokes and being configured to rotate a respective one of the plurality of spokes. In certain embodiments, each rotating motor rotates a respective one of the plurality of spokes at an angle between -90 degrees and 90 degrees. In some embodiments, each rotating motor rotates a respective one of the plurality of spokes at an angle up to 180 degrees. In some embodiments, the rotating disk includes a sensor disposed on a back surface of at least one of the platens for measuring characteristics of an ion beam. In some embodiments, the sensor includes an array of holes. In some embodiments, the sensor includes slots.

[0009] According to another embodiment, an ion implantation system is disclosed. The system includes an ion source for generating ions, an accelerator for accelerating the ions to generate a spot beam, and the rotating disk described above. In some embodiments, the rotating disk is configured to translate in a direction perpendicular to the central axis, providing a two-dimensional mechanical scan. In some embodiments, the central hub is rotatably attached to a structure, in which case the structure linearly translates in a direction perpendicular to the central axis. In some embodiments, the central hub is rotatably attached to a pivoting arm, in which case the pivoting arm rotates to translate the rotating disk in a direction perpendicular to the central axis.

[0010] According to another embodiment, a rotating disk for processing a plurality of workpieces is disclosed. The rotating disk includes a central hub adapted to rotate about a central axis, a hub controller disposed within the central hub, a plurality of spokes radially extending outwardly from the central hub, each of the plurality of spokes being adapted to rotate about a respective axis radially extending from the central hub, a platen disposed at a distal end of each of the plurality of spokes and configured to electrostatically clamp a respective workpiece, and a plurality of rotating motors disposed within the central hub, each rotating motor communicating with a respective one of the plurality of spokes and configured to rotate a respective one of the plurality of spokes. In some embodiments, the hub controller is configured to execute a sequence for attaching a workpiece to the platen, the sequence for attaching the workpiece including actuating one of the plurality of rotating motors to rotate the platen so that the front face is horizontal to enable the workpiece to be placed on the front face of the platen, and enabling the electrostatic clamping of the platen after the workpiece is placed on the front face. In some embodiments, the rotating disk includes a valve for regulating the flow rate of backside gas to one or more of the platens. In some embodiments, the sequence for attaching the workpiece further includes enabling the flow of backside gas after the workpiece is electrostatically clamped. In some embodiments, the sequence for attaching the workpiece further includes actuating one of the plurality of rotating motors to rotate the platen so that the front face of the platen is at a desired injection angle after the workpiece is electrostatically clamped. In some embodiments, the hub controller is configured to execute a sequence for removing a workpiece from the platen, the sequence including actuating one of the plurality of rotating motors to rotate the platen so that the front face is horizontal to enable the workpiece to be removed from the front face of the platen, and disabling the electrostatic clamping of the platen after the platen is rotated to a horizontal position.In some embodiments, the rotating disk comprises a valve for regulating the flow rate of backside gas to one or more of the platens. In some embodiments, the sequence for removing the workpiece further includes stopping the flow of backside gas before the electrostatic clamp is deactivated. In certain embodiments, the rotating disk comprises a sensor disposed on the backside of at least one of the platens. In that case, the hub controller is configured to execute a sequence for measuring the characteristics of the incident ion beam. The sequence includes operating one of the plurality of rotation motors to rotate the platen such that the backside of the platen is exposed to the incident ion beam so that the incident ion beam impinges on the sensor, and receiving the output from the sensor. In that case, the output indicates the characteristics of the incident ion beam. In certain embodiments, the rotating disk comprises a temperature sensor disposed on one or more of the platens. In that case, the hub controller monitors the temperature of the platen.

[0011] For a better understanding of the present disclosure, reference is made to the accompanying drawings, which are incorporated herein by reference.

Brief Description of the Drawings

[0012]

Figure 1A

Figure 1B

Figure 2A

Figure 2B

Figure 3

Figure 4A

Figure 4B

Figure 5

Figure 6

Figure 7

Figure 8A

Figure 8B

Figure 9A

Figure 9B

Figure 10

DETAILED DESCRIPTION OF THE INVENTION

[0013] The present disclosure describes the use of a rotating disk in combination with a semiconductor processing system for implanting ions having high energy and low angular spread. There are various semiconductor processing systems that can be used with the rotating disk.

[0014] As shown in FIG. 1A, the semiconductor processing system includes an ion source 100 used to generate an ion beam. In one embodiment, a positive ion beam 101 can be generated in a conventional manner, such as using a Bernas or an indirectly heated cathode (IHC) ion source. Of course, other types of ion sources can also be employed. A supply gas is supplied to the ion source 100, and then the ion source 100 is energized to generate ions. In certain embodiments, the supply gas can be hydrogen, boron, phosphorus, arsenic, helium, or other suitable species. These ions are then extracted from the ion source 100 using an extraction optical element.

[0015] The positive ion beam 101 exiting the ion source 100 can be coupled to the Mg charge exchange cell 110. The Mg charge exchange cell 110 converts the positive ion beam 101 into a negative ion beam 111. Of course, other mechanisms for generating negative ion beams are known in the art. The mechanism used to generate the negative ion beam is not limited by the present disclosure.

[0016] The negative ion beam 111 can be directed towards a mass spectrometer 120. The mass spectrometer 120 can allow only specific ion species to pass through. The negative ions exiting the mass spectrometer 120 are directed towards a tandem accelerator 130.

[0017] The tandem accelerator 130 has two paths. The two paths are separated by a stripper tube 133. The input path 131 includes a plurality of input electrodes. These input electrodes can be any suitable conductive material such as titanium or other metals. The outermost input electrode may be grounded. Each of the subsequent input electrodes can be biased at an increasingly positive voltage as it approaches the stripper tube 133.

[0018] The input path 131 is connected to the stripper tube 133. The stripper tube 133 is positively biased with respect to the outermost input electrode. The stripper tube 133 includes an injection conduit into which a stripper gas is injected. The stripper gas can contain neutral molecules. These neutral molecules can be any suitable species such as argon or nitrogen, but are not limited thereto. The stripper tube 133 has an inlet disposed on the same side as the input path 131. The outlet of the stripper tube 133 communicates with the output path 132.

[0019] In other words, the stripper tube 133 is positively biased to attract the negative ion beam 111 through the input path 131. The stripper tube 133 removes electrons from the incoming ions and converts those ions from negative ions to positive ions.

[0020] The stripper tube 133 is positive with respect to the electrodes in the output path 132. The subsequent output electrodes can have a smaller positive bias as they move further away from the stripper tube 133. For example, the outermost output electrode may be grounded. Thus, the positive ions in the stripper tube 133 are accelerated through the output path 132.

[0021] In this way, the ions are accelerated twice. First, the negative ions are accelerated through the input path 131 towards the stripper tube 133. This acceleration is based on the difference between the voltage of the outermost input electrode and the voltage of the stripper tube 133. Next, the positive ions are accelerated through the output path 132. This acceleration is based on the difference between the voltage of the stripper tube 133 and the voltage of the outermost output electrode in the output path 132.

[0022] The accelerator power supply 134 can be used to supply voltages to the stripper tube 133, as well as the electrodes in the input path 131 and the electrodes in the output path 132. The accelerator power supply 134 can supply voltages up to 2.5 MV, but other voltages (higher or lower) are also possible. Thus, the voltage applied by the accelerator power supply 134 is changed to modify the injection energy.

[0023] After exiting the tandem accelerator 130, the positive ion beam 135 can enter the filter magnet 140. The filter magnet 140 can allow only ions of a specific charge to pass through. In other embodiments, the filter magnet 140 may not be employed.

[0024] The output of the filter magnet, which can be a spot ion beam 155, is then directed towards the rotating disk 300. The workpiece 10 can be placed on each of a plurality of platens arranged on the rotating disk. In certain embodiments, a correcting magnet can be arranged between the filter magnet 140 and the rotating disk 300.

[0025] Furthermore, the semiconductor processing apparatus includes a controller 180. The controller 180 may include a processing unit such as a microcontroller, a personal computer, a dedicated controller, or another suitable processing unit. The controller 180 may also include a non-transitory computer-readable storage element such as a semiconductor memory, a magnetic memory, or another suitable memory. This non-transitory storage element may contain instructions and other data that enable the controller 180 to perform the functions described herein.

[0026] The controller 180 may be communicatively coupled to the accelerator power supply 134 to control the injection energy. Additionally, as will be described in more detail below, the controller 180 may be communicatively coupled to the rotating disk 300. The controller 180 may also be communicatively coupled to other components.

[0027] A second embodiment is shown in FIG. 1B. Components common to FIG. 1A are given the same reference numerals.

[0028] As described above, the semiconductor processing system includes an ion source 100 used to generate an ion beam. The ion source 100 has an aperture through which ions can be extracted from the ion source 100. These ions can be extracted from the ion source 100 by applying a negative voltage to an extraction optical element 103 disposed outside the ion source 100 proximate to the extraction aperture. The ions can then enter a mass spectrometer 120. The mass spectrometer 120 may be a magnet that can pass ions having a specific mass-to-charge ratio. This mass spectrometer 120 is used to separate only the desired ions. Then, the desired ions enter the linear accelerator 200.

[0029] Next, the desired ions enter the buncher 210. The buncher 210 generates a group or bunch of ions that move together. The buncher 210 may comprise a plurality of drift tubes. In that case, an alternating voltage may be supplied to at least one of the drift tubes. One or more of the other drift tubes may be grounded. The drift tube to which the alternating voltage is supplied may have the function of accelerating the ion beam and manipulating it into discrete bunches.

[0030] The linear accelerator 200 includes one or more cavities 201. Each cavity 201 comprises a resonator coil 202 that can be energized by an electromagnetic field generated by an excitation coil 205. The excitation coils 205 are disposed within the cavities 201 together with their respective resonator coils 202. The excitation coils 205 are energized by an excitation voltage that may be an RF signal. The excitation voltage may be supplied by respective RF generators 204. In other words, the excitation voltage applied to each excitation coil 205 may be independent of the excitation voltage supplied to any other excitation coil 205. Each excitation voltage is preferably modulated at the resonant frequency of its respective cavity 201.

[0031] When the excitation voltage is applied to the excitation coil 205, a voltage is induced in the resonator coil 202. As a result, the resonator coil 202 within each cavity 201 is driven by a sinusoidal voltage. Each resonator coil 202 may be electrically connected to its respective accelerator electrode 203. Ions pass through the apertures within each accelerator electrode 203.

[0032] The entry of the bunch into a particular accelerator electrode 203 occurs at the following timing. That is, as the bunch approaches, the potential of the accelerator electrode 203 becomes negative, but switches to positive when the bunch passes through the accelerator electrode 203. In this way, the bunch is accelerated as it enters the accelerator electrode 203 and repelled as it exits. As a result, the bunch is accelerated. This process is repeated for each accelerator electrode 203 within the linear accelerator 200. Each accelerator electrode 203 increases the acceleration of the ions.

[0033] After the beam exits the linear accelerator 200, the ions, which can be the spot ion beam 155, are directed towards the rotating disk 300.

[0034] The controller 180 may communicate with the RF generator 204 to control the injection energy. Additionally, as will be described in more detail below, the controller 180 may communicate with the rotating disk 300. The controller 180 may also communicate with other components.

[0035] Of course, the ion injection system may include other components such as quadrupole elements, additional electrodes for accelerating or decelerating the beam, and other elements.

[0036] In both of these embodiments, the ion injection system includes an ion source and an accelerator for accelerating the ions. The output from the semiconductor processing system, which can be the spot ion beam 155, is directed towards the rotating disk 300. One embodiment of the rotating disk 300 is shown in FIG. 2A. A side view of this rotating disk is shown in FIG. 2B.

[0037] The rotating disk 300 includes a central hub 310 that rotates about a central axis 311. The rotating disk 300 may be connected to the structure 330 using a spindle assembly 340. Alternatively, the rotating disk 300 may be attached to a pivoting arm, as will be described in more detail below.

[0038] Extending outwardly from the central hub 310 are a plurality of spokes 315. Each spoke 315 has a respective platen 320 attached to the distal end of the spoke 315. There may be between 4 and 20 or more platens 320. In some embodiments, the diameter of the platen 320 may be approximately 12 inches, and the diameter of the central hub 310 may be between 12 and 24 inches. The platen 320 may be attached to the spoke 315 so as to be fixed.

[0039] As shown in FIG. 9A, during operation, the spot ion beam 155 is directed towards the area near the rotating disk 300. The central hub 310 rotates along path 317 around the central axis 311. In certain embodiments, the rotation speed may be between 30 RPM and 1000 RPM. In other embodiments, the rotation speed may be 300 RPM or less. Of course, other rotation speeds are also possible. Further, the central hub 310 can be linearly translated horizontally, for example, along path 318, by moving the structure 330. The linear speed may be between 100 and 500 mm / sec, but other speeds are also possible. Path 318 is defined such that at both ends of the path, the spot ion beam 155 does not collide with the platen 320. In other words, at one end of path 318, the spot ion beam 155 extends beyond the outermost edge of the platen 320. At the other end of path 318, the spot ion beam 155 is directed towards the area between the central hub 310 and the inner edge of the platen 320. Thus, in certain embodiments, the spoke 315 has a length greater than the maximum diameter of the spot ion beam 155. Thereby, there is a position where the spot ion beam 155 is between the central hub 310 and the platen 320. In certain embodiments, the spoke 315 may be at least 6 inches in length. By including the spoke 315, the central hub 310 is not affected by the spot ion beam 155 when the central hub 310 is translated horizontally along path 318. Further, path 318 may be perpendicular to the rotation of the central hub 310 when the platen passes through the spot ion beam 155, resulting in a two-dimensional mechanical scan.

[0040] In another embodiment shown in FIG. 9B, the rotating disk 300 is attached to a swivel arm 319. The length of the swivel arm 319 can be made long enough such that the path 324 of the central hub 310 has a radius of curvature between approximately 350 and 750 mm. In this way, path 324 is generally perpendicular to the rotation of the central hub 310 when the platen passes through the spot ion beam 155, resulting in a two-dimensional mechanical scan.

[0041] Referring to FIG. 2B, each of the platens 320 can utilize an electrostatic clamp. The electrostatic clamp can be realized using either an alternating current or a direct current voltage. In one embodiment, the upper surface of the platen can be a dielectric material such as ceramic. Under the upper surface, there can be a plurality of electrodes 321.

[0042] In the case of a DC clamp, there are two electrodes 321. The first electrode is biased with a positive voltage having a predetermined magnitude, and the second electrode is biased with a negative voltage having the same magnitude. The electrodes can be of an appropriate shape. In one embodiment, the two electrodes can be adjacent spirals. The magnitude of the DC voltage can be between 200 and 2000V.

[0043] In the case of the AC clamp shown in FIG. 3, an even number of electrodes 321 such as six electrodes can be present. The electrodes 321 can be arranged as opposing pairs. In that case, the phases of the two electrodes of a pair have a phase difference of 180 degrees. Thus, each pair of electrodes can be electrically connected to respective bipolar power signals such as rectangular waves. Thereby, one of the electrodes of a pair receives a positive output, and the other of the electrodes of that pair receives a negative output. Rectangular wave outputs having the same period and amplitude are applied to all the electrodes. However, each rectangular wave output is phase-shifted from the adjacent ones. The phase between adjacent electrodes can be equal to 360 degrees / N, where N is the number of electrodes.

[0044] In certain embodiments, the frequency of the alternating current voltage or the pulsed direct current voltage can be between 1 and 60 Hz. On the other hand, the amplitude can be between 200 and 4000V. In certain embodiments, there are six electrodes configured as three pairs. One of these pairs of electrodes is powered by a first rectangular wave, while the second pair of electrodes is powered by a second rectangular wave, and the second rectangular wave has a 120-degree phase shift with respect to the first rectangular wave. Similarly, the third rectangular wave is phase-shifted by 120 degrees from the second rectangular wave. Of course, other configurations are also within the scope of the present disclosure.

[0045] In certain embodiments, the electrode power supply 305 is disposed within the central hub 310. In some embodiments, the electrode power supply 305 may generate the signals necessary for electrostatic clamping of the workpiece to each platen 320. In other embodiments, the signals necessary to clamp the workpiece may be provided via the spindle assembly 340.

[0046] Each of the platens 320 is connected to the central hub 310 via respective spokes 315. Within each spoke 315 is an electrical conduit for its respective platen 320. These electrical conduits carry the electrical signals necessary for electrostatic clamping. Further, each spoke 315 may also carry coolant and backside gas. The coolant and backside gas may be supplied to the central hub 310 via the spindle assembly 340. Various techniques such as ferromagnetic fluid seals can be used to supply gas and coolant to the central hub 310.

[0047] In some embodiments, individual valves for each platen may be present within the central hub 310 for supplying backside gas to each platen 320. In other embodiments, valves for supplying backside gas to a subset of the platens 320 may be present. For example, if there are nine platens, three valves may be present within the central hub. Each valve controls the flow rate of backside gas to three platens. In yet another embodiment, a single valve may be present. The single valve is used to control the flow rate of backside gas to all of the platens 320. The backside gas is typically supplied between 4 and 20 Torr.

[0048] The flow rate of coolant to the platens 320 may be adjusted by valves disposed within or outside of the central hub 310.

[0049] In certain embodiments, the spoke 315 and the corresponding platen 320 are rigidly attached to each other. Further, in some embodiments, each spoke 315 is rotatably movable about an axis 316 extending radially from the central hub 310. In other words, the spoke 315 can rotate relative to the central hub 310 about an axis perpendicular to the central axis 311. As shown in FIG. 3, a rotation motor 313 is associated with each spoke 315 to control the rotation of the spoke 315.

[0050] Further, as described above, the spoke 315 can rotate relative to the central hub 310. Accordingly, one rotation motor 313 for each platen 320 is also included within the central hub 310. In some embodiments, a hub controller 312 is disposed within the central hub 310. The hub controller 312 may include a processing unit such as a microcontroller, a personal computer, a dedicated controller, or another suitable processing unit. The hub controller 312 may also include a non-transitory computer-readable storage element such as a semiconductor memory, a magnetic memory, or another suitable memory. This non-transitory storage element may contain instructions and other data that enable the hub controller 312 to perform the functions described herein.

[0051] The hub controller 312 receives communication signals 326 passed to the central hub 310 via the spindle assembly 340. These communication signals 326 may be generated by the controller 180 shown in FIGS. 1A-1B. Based on these communication signals 326, the hub controller 312 may perform various functions. For example, the hub controller 312 may control whether the signal supplied to the electrode 321 is enabled or disabled. The signal to the electrode 321 may be disabled when the workpiece is removed from the platen 320. The signal to the electrode 321 may be enabled after the workpiece is attached to the platen 320, as described in more detail below.

[0052] Furthermore, the hub controller 312 can control a valve for the flow of fluid to the platen 320. FIG. 10 shows a block diagram illustrating possible fluid flow paths. The hub controller 312 can control the flow rate of the backside gas to each platen 320. For example, a fluid conduit 350 that conveys the backside gas can pass through the spindle assembly 340. This fluid conduit 350 can then branch to each of the platens 320. In certain embodiments, the flow rate of the backside gas to each platen 320 is independently controlled by the hub controller 312 via the use of a plurality of gas valves 351. In another embodiment, one gas valve 351 can be used to control the flow rate of the backside gas to all of the platens 320.

[0053] The hub controller 312 can also control the flow rate of the coolant to each platen 320. An inlet coolant conduit 360 and an outlet coolant conduit 361 can pass through the spindle assembly 340. In certain embodiments, the flow rate of the coolant to each platen 320 is independently controlled by the hub controller 312 via the use of a plurality of coolant valves 362. In another embodiment, one coolant valve 362 can be used to control the flow rate of the coolant to all of the platens 320.

[0054] In another embodiment, the coolant valve 362 may not be used within the central hub 310. Rather, the flow rate of the coolant to the platen 320 can be controlled outside of the central hub, such as by a coolant supply chiller.

[0055] The hub controller 312 can also monitor the temperature of each platen 320, such as via the use of temperature sensors 365 disposed on one or more of the platens 320. For example, the flow rate of the coolant passing through the coolant valve 362 can be related to the temperature of each respective platen 320 as measured by the temperature sensor 365. Furthermore, the hub controller 312 can also provide status and other information back to the controller 180 via the communication signal 326.

[0056] When there is no coolant valve 362 within the central hub 310, the hub controller 312 may provide temperature information to the controller 180 via the communication signal 326. The controller 180 may then use this information to control the coolant supply chiller.

[0057] Referring to FIG. 3, the hub controller 312 may also control one or more rotary motors 313. The interior of the central hub 310 may be sealed from the reduced pressure environment existing outside the central hub 310. In some embodiments, the interior of the central hub 310 may be maintained at atmospheric pressure. In other embodiments, the interior of the central hub 310 may be maintained at a pressure less than atmospheric pressure but higher than the pressure outside the central hub 310. In certain embodiments, backside gas may be used to generate the pressure inside the central hub 310.

[0058] The rotary motor 313 is used to rotate the spoke 315 to a predetermined angle. In some embodiments, the rotary motor 313 may rotate the spoke 315 to an angle between 0 degrees and 90 degrees. In some embodiments, the rotary motor 313 may rotate the spoke 315 to an angle between -90 degrees and 90 degrees. For example, as shown in FIG. 4A, the rotary motor 313 may rotate the platen 320 to an angle of 45 degrees. Further, as shown in FIG. 4B, the rotary motor 313 may rotate the platen 320 to an angle of 90 degrees.

[0059] When rotated at a 90-degree angle, the central hub 310 can be rotated about the central axis 311 such that one of the platens 320, such as platen 320a, is horizontal. In this horizontal position, the workpiece can be attached to or removed from the platen 320a. After the workpiece is attached or removed, the central hub 310 can be rotated about the central axis 311 to move another platen 320 to the horizontal position. In one embodiment, the central hub 310 can rotate by an angle of 360 degrees / P about the central axis 311. Here, P is the number of platens 320, and it is assumed that the spokes 315 are evenly distributed on the outer circumference of the central hub 310.

[0060] Accordingly, in one embodiment, a method of attaching and removing a plurality of workpieces using the central hub 310 is shown in FIG. 5. As shown in box 500, the rotation motor 313 rotates the platen by a 90-degree angle. Then, as shown in box 510, the central hub 310 is rotated about its central axis 311 such that one of the platens 320a is horizontal. When the workpiece is removed, as shown in box 520, the electrostatic clamp is deactivated when the platen is in the horizontal position. Then, as shown in box 530, the workpiece is placed on or removed from the platen 320a. When the workpiece is placed on the platen 320a, as shown in box 540, the electrostatic clamp is activated. Then, as shown in box 510, the central hub 310 is rotated until another platen is in the horizontal position. Then, the sequence shown in boxes 510 - 540 is repeated until the workpiece is placed on and / or removed from all of the platens 320 or until there is no workpiece left.

[0061] In some embodiments, such as those shown in FIG. 5, note that all of the platens 320 are rotated by an angle of 90 degrees (see box 500) before a workpiece is attached to and / or removed from any of the platens.

[0062] However, a plurality of other embodiments are possible. In a plurality of other embodiments, each platen 320 is rotated immediately before a workpiece is attached to and / or removed from the platen 320. In other words, the box 500 can be moved so as to be executed each time the central hub is rotated.

[0063] In some embodiments, workpieces are processed in groups that can be transported within a FOUP. In certain embodiments, the FOUP can include 25 workpieces. Thus, if the number of platens is not a factor of the number of workpieces within the FOUP, there will be unoccupied platens. As an example, assume that there are 25 workpieces within the FOUP and 9 platens 320 around the central hub 310. In the first pass, 9 workpieces can be processed. In the second pass, a second set of 9 workpieces can be processed. In the third pass, only 7 workpieces are processed. Thus, in this third pass, there are 2 unoccupied platens.

[0064] In certain embodiments, the central hub 310 addresses this issue by enabling the platen 320 to be rotated by an angle of 180 degrees such that the spot ion beam 155 impinges on the back surface of the platen 320. This is shown in FIG. 6, where the platen 320b is rotated by 180 degrees about the axis 316. Thereby, the back surface of the platen 320b faces the spot ion beam.

[0065] This approach eliminates the need for dummy wafers. Dummy wafers are used to protect the top surface of the platen 320 from direct impact from the spot ion beam 155. Instead of using a dummy wafer to protect the top surface of the platen 320, simply rotate the unoccupied platen by only 180 degrees. Thereby, the back surface of the platen 320 faces the spot ion beam 155.

[0066] In some embodiments, the number of platens 320 disposed on the rotating disk 300 can be associated with the number of workpieces included within the FOUP so as to minimize the idle time. For example, it may be advantageous for the number of workpieces within the FOUP to be a multiple or approximately a multiple of the number of platens 320. Thus, if there are 25 workpieces within the FOUP, the rotating disk can have 5 or 25 platens 320 on the rotating disk. This ensures that there are no unoccupied platens. However, other numbers of platens may also be useful. If there are 13 platens, there is only one unoccupied platen, and all of the workpieces within the FOUP can be processed in two passes. If there are 9 platens, there are only two unoccupied platens, and all of the workpieces within the FOUP can be processed in three passes. Of course, other numbers of platens may also be utilized.

[0067] In certain embodiments, information regarding the spot ion beam can be collected by the platen 320b rotated by only 180 degrees. For example, as shown in FIG. 7, sensors 380 can be disposed on the back surface of one or more platens 320. These sensors 380 can be Faraday sensors. The sensors 380 can be used to measure the characteristics of the ion beam, such as dose measurement and beam uniformity measurement. The output from these sensors 380 can communicate with the hub controller 312. In some embodiments, the hub controller 312 returns information regarding the characteristics of the ion beam to the controller 180 via the communication signal 326. This can enable better beam control.

[0068] In certain embodiments, as shown in FIG. 8A, sensor 380 may include an array 381 of holes or other openings. In a plurality of other embodiments, as shown in FIG. 8B, the sensor may include one or more slots 382.

[0069] Referring to FIG. 7, sensor 380 may be oriented differently. For example, one or more sensors 380, such as sensor 380a, may be oriented such that the longer dimension is radial. One or more sensors 380, such as sensor 380b, may be oriented such that the longer dimension is perpendicular to the radial direction. The orientation of the sensor may optimize its measurement in one of two directions of movement. For example, sensor 380b may be better oriented to observe a beam along path 318. Sensor 380a may be better oriented to observe a beam along path 317.

[0070] The systems and methods described herein have a number of advantages. This rotating disk enables the platen 320 to utilize an electrostatic clamp to clamp the workpiece. One advantage of this approach is that the platen can be tilted at any desired injection angle. This may not be possible with existing mechanical clamp approaches. In particular, the use of an electrostatic clamp allows the axis of rotation of the platen to be parallel to the ion beam when zero-degree injection is desired. This eliminates the angular error associated with conventional disk designs. Conventional disks had the pedestal attached at an angle to the spin axis, so when it was desired to perform zero-degree injection, the spin axis of the disk was not aligned with the ion beam, resulting in an injection angle error. Further, the current rotating disk can simplify the attachment and removal procedures due to the ability to rotate the platen by 90 degrees. This allows the workpiece to be exchanged while the workpiece is in the horizontal orientation. Further, in certain embodiments, the dummy wafer can be eliminated by rotating the unoccupied platen by 180 degrees. In certain embodiments, these rotated platens are also used to collect information regarding the spot ion beam at the exact location where the spot ion beam impacts the workpiece.

[0071] The present disclosure is not limited in scope by the specific embodiments described herein. Indeed, in addition to what is described herein, various other embodiments and modifications of the present disclosure will be apparent to those of ordinary skill in the art from the foregoing description and the accompanying drawings. Accordingly, such other embodiments and modifications are intended to be included within the scope of the present disclosure. Further, although the present disclosure has been described herein in the context of specific embodiments for a particular purpose in a particular environment, those of ordinary skill in the art will recognize that its usefulness is not limited thereto, and that the present disclosure can be beneficially implemented in any number of environments for any number of purposes. Accordingly, the claims set forth below are to be construed in view of the broadest possible scope and spirit of the present disclosure described herein.

Claims

1. A rotating disk for processing a plurality of workpieces, comprising: A central hub adapted to rotate about a central axis; A plurality of spokes radially extending outwardly from the central hub, each of the plurality of spokes being adapted to rotate about a respective axis radially extending from the central hub; A platen disposed at a distal end of each of the plurality of spokes, each platen comprising a plurality of electrodes and being configured to electrostatically clamp a respective workpiece; and A plurality of rotating motors disposed within the central hub, each rotating motor communicating with a respective one of the plurality of spokes and being configured to rotate the respective one of the plurality of spokes.

2. The rotating disk according to claim 1, wherein each rotating motor rotates the respective one of the plurality of spokes at an angle between -90 degrees and 90 degrees.

3. The rotating disk according to claim 1, wherein each rotating motor rotates the respective one of the plurality of spokes at an angle up to 180 degrees.

4. The rotating disk according to claim 1, further comprising a sensor disposed on a back surface of at least one of the platens for measuring characteristics of an ion beam.

5. The rotating disk according to claim 4, wherein the sensor includes an array of holes.

6. The rotating disk according to claim 4, wherein the sensor includes slots.

7. An ion source for generating ions; An accelerator for accelerating the ions to generate a spot beam; and An ion implantation system comprising the rotating disk according to claim 1.

8. The ion implantation system according to claim 7, wherein the rotating disk is configured to translate in a direction perpendicular to the central axis, providing a two-dimensional mechanical scan.

9. The ion implantation system according to claim 8, wherein the central hub is rotatably attached to a structure, and the structure translates linearly in a direction perpendicular to the central axis.

10. The ion implantation system according to claim 8, wherein the central hub is rotatably attached to a swivel arm, and the swivel arm rotates to translate the rotating disk in a direction perpendicular to the central axis.

11. A rotating disk for processing a plurality of workpieces, a central hub adapted to rotate about a central axis, a hub controller disposed within the central hub, a plurality of spokes radially extending outwardly from the central hub, each of the plurality of spokes being adapted to rotate about a respective axis radially extending from the central hub, a platen disposed at a distal end of each of the plurality of spokes and configured to electrostatically clamp a respective workpiece, and a plurality of rotary motors disposed within the central hub, each rotary motor communicating with a respective one of the plurality of spokes and configured to rotate the respective one of the plurality of spokes, the rotating disk comprising the plurality of rotary motors.

12. The hub controller is configured to execute a sequence for attaching a workpiece to the platen, the sequence for attaching the workpiece comprising actuating one of the plurality of rotary motors to rotate the platen so that the front surface is horizontal to enable the workpiece to be disposed on the front surface of the platen, and after the workpiece is disposed on the front surface, enabling electrostatic clamping of the platen. The rotating disk according to claim 11.

13. The rotating disk according to claim 12, comprising a valve for regulating the flow rate of backside gas to one or more of the platens.

14. The sequence for attaching the workpiece further comprises enabling the flow of backside gas after the workpiece is electrostatically clamped. The rotating disk according to claim 13.

15. The sequence for attaching the workpiece further comprises actuating one of the plurality of rotary motors to rotate the platen so that the front surface of the platen is at a desired injection angle after the workpiece is electrostatically clamped. The rotating disk according to claim 14.

16. The hub controller is configured to execute a sequence for removing a workpiece from the platen, the sequence comprising Actuating one of the plurality of rotary motors to rotate the platen so that the front surface thereof is horizontal to enable the workpiece to be removed from the front surface of the platen, and The rotary disk according to claim 11, further comprising disabling the electrostatic clamp of the platen after the platen is rotated to a horizontal posture.

17. The rotary disk according to claim 16, further comprising a valve for adjusting the flow rate of the backside gas to one or more of the platens.

18. The sequence for removing the workpiece The rotary disk according to claim 17, further comprising stopping the flow of the backside gas before the electrostatic clamp is disabled.

19. The rotary disk according to claim 11, further comprising a sensor disposed on the back surface of at least one of the platens, wherein the hub controller is configured to execute a sequence for measuring characteristics of an incident ion beam, and the sequence Actuating one of the plurality of rotary motors to rotate the platen so that the back surface thereof is exposed to the incident ion beam such that the incident ion beam impinges on the sensor, and Receiving an output from the sensor, the output indicating characteristics of the incident ion beam.

20. The rotary disk according to claim 11, further comprising a temperature sensor disposed on one or more of the platens, wherein the hub controller monitors the temperature of the platen.

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