Beam shaping by ion source gas injection.

Abstract

An ion source for extracting a ribbon ion beam with improved height uniformity is disclosed. A gas nozzle is disposed within the chamber proximate to an extraction aperture. Gas introduced near the injection aperture serves to shape the ribbon ion beam as it is extracted. For example, the height of the ribbon ion beam can be reduced by injecting gas above and below the ion beam to compress the extracted ion beam in height. In some embodiments, a feed gas is introduced near the extraction aperture. In other embodiments, a shield gas, such as an inert gas, is introduced near the extraction aperture.

Description

[Technical Field]

[0001] This application claims priority to U.S. Patent Application No. 17 / 513,245, filed October 28, 2021, the disclosure of which is incorporated herein by reference in its entirety.

[0002] SUMMARY OF THE DISCLOSURE Embodiments of the present disclosure relate to a system for injecting gas into an ion source to shape an extracted ion beam. [Background technology]

[0003] Semiconductor devices are manufactured using several processes, some of which involve implanting ions into the workpiece. Various ion sources can be used to generate ions. One such ion source is the indirectly heated cathode (IHC) ion source. An IHC ion source includes a filament positioned behind a cathode. The cathode may be maintained at a more positive voltage than the filament. When a current is applied to the filament, the filament emits thermal electrons, which are accelerated toward the more positively charged cathode. These thermal electrons serve to heat the cathode, which then causes the cathode to emit electrons into the ion source chamber. The cathode is located at one end of the chamber. A repeller is typically located at the end of the chamber opposite the cathode.

[0004] In certain embodiments, the IHC ion source is configured to extract a ribbon ion beam. The width of the ribbon ion beam is significantly greater than the height of the ribbon ion beam. Unfortunately, in many systems, the height of the extracted ion beam is not constant due to non-uniform plasma density within the ion source. For example, if the plasma density is highest near the center of the chamber, the height of the ribbon ion beam may be greatest near the center of the extraction aperture.

[0005] Variations in the height of the ion beam can be problematic as they can lead to non-uniform implant doses. Therefore, some ion implantation systems use additional components, such as lenses, to correct this problem. However, these additional components add cost and complexity.

[0006] Therefore, it would be beneficial to have a system that can control the height uniformity of a ribbon ion beam being extracted from an ion source. Summary of the Invention

[0007] An ion source for extracting a ribbon ion beam with improved height uniformity is disclosed. A gas nozzle is positioned within the chamber proximate to the extraction aperture. Gas introduced near the extraction aperture serves to shape the ribbon ion beam as it is extracted. For example, the height of the ribbon ion beam can be reduced by injecting gas above and below the ion beam to compress the extracted ion beam in the height direction. In some embodiments, a feed gas is introduced near the extraction aperture. In other embodiments, a shield gas, such as an inert gas, is introduced near the extraction aperture.

[0008] According to one embodiment, an ion source is disclosed. The ion source includes a chamber having a first end, a second end, and a plurality of walls connecting the first end and the second end, one of the plurality of walls being an extraction plate having an extraction opening with a width greater than its height; a plasma generator for generating plasma in the chamber; a gas inlet communicating with a gas channel; a supply channel communicating with the gas inlet for supplying a feed gas to the chamber; and a gas nozzle disposed in the chamber near the extraction opening, the gas nozzle communicating with the gas channel for providing a flow of the feed gas near the extraction opening. In some embodiments, the plurality of walls includes a bottom wall opposite the extraction plate and a side wall adjacent to the extraction plate, the gas channel being disposed in the side wall. In some embodiments, the plurality of walls includes a bottom wall opposite the extraction plate and a side wall adjacent to the extraction plate, the gas channel including a tube disposed proximate an inner or outer surface of the side wall. In some embodiments, the ion source includes a plate gas channel disposed within the extraction plate, the plate gas channel communicating with the gas channel, and a gas nozzle disposed on an inner surface of the extraction plate adjacent to the extraction opening. In certain embodiments, the walls include a bottom wall facing the extraction plate and a side wall adjacent to the extraction plate, and the gas nozzle is disposed on an inner surface of the side wall adjacent to the extraction plate. In some embodiments, the extraction plate includes a face plate and an extraction liner disposed between the interior of the chamber and the face plate, the extraction liner being shaped such that a gap exists between the extraction liner and the face plate, the gap communicating with the gas channel. The ion source further includes a plate gas channel disposed within the extraction liner, the plate gas channel communicating with the gap, and a gas nozzle disposed on a surface of the extraction liner adjacent to the extraction opening. In some embodiments, the gas nozzle dimensions vary along the width of the extraction aperture to improve height uniformity of the extracted ribbon ion beam. In some embodiments, the plasma generator comprises an indirectly heated cathode (IHC).

[0009] According to another embodiment, an ion implantation system is disclosed, comprising the ion source, mass analyzer, and platen described above.

[0010] According to another embodiment, an ion source is disclosed. The ion source includes a chamber having a first end, a second end, and a plurality of walls connecting the first end and the second end, one of the plurality of walls being an extraction plate having an extraction opening with a width greater than its height; a plasma generator for generating plasma in the chamber; a gas inlet communicating with a gas channel; a gas nozzle disposed near the extraction opening and communicating with the gas channel; and a second gas inlet communicating with a supply channel for supplying a supply gas to the chamber. The supply channel and the gas channel are not in fluid communication with each other. In some embodiments, the plurality of walls includes a bottom wall facing the extraction plate and a side wall adjacent to the extraction plate, and the gas channel is disposed within the side wall. In some embodiments, the plurality of walls includes a bottom wall facing the extraction plate and a side wall adjacent to the extraction plate, and the gas channel includes a tube disposed proximate to an inner or outer surface of the side wall. In some embodiments, the ion source includes a plate gas channel disposed within the extractor plate, the plate gas channel communicating with the gas channel, and a gas nozzle disposed on an inner surface of the extractor plate adjacent to the extraction opening. In certain embodiments, the walls include a bottom wall facing the extractor plate and a side wall adjacent to the extractor plate, and the gas nozzle is disposed on an inner surface of the side wall adjacent to the extractor plate. In some embodiments, the extractor plate includes a face plate and an extractor liner disposed between the interior of the chamber and the face plate, the extractor liner being shaped such that a gap exists between the extractor liner and the face plate, the gap communicating with the gas channel. The ion source further includes a plate gas channel disposed within the extractor liner, the plate gas channel communicating with the gap, and a gas nozzle disposed on a surface of the extractor liner adjacent to the extraction opening. In some embodiments, the ion source includes a first gas container in fluid communication with the gas inlet and a second gas container in fluid communication with the second gas inlet.In some embodiments, the ion source comprises a gas vessel in fluid communication with a first mass flow controller and a second mass flow controller, the first mass flow controller controlling a flow rate through a gas inlet and the second mass flow controller controlling a flow rate through a second gas inlet. In some embodiments, the flow rates through the gas inlet and the second gas inlet are independently controlled. In some embodiments, the gas nozzle dimensions vary along the width of the extraction aperture to improve height uniformity of the extracted ribbon ion beam. In some embodiments, the plasma generator comprises an indirectly heated cathode (IHC).

[0011] According to another embodiment, an ion implantation system is disclosed, comprising the ion source, mass analyzer, and platen described above.

[0012] For a better understanding of the present disclosure, reference is made to the accompanying drawings, which are incorporated herein by reference. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 shows a block diagram of an ion source according to one embodiment. [Figure 2] FIG. 2 is a block diagram of an ion implantation system using the IHC ion source of FIG. 1. [Figure 3A] 1 shows a cross-sectional view of an ion source according to one embodiment. [Figure 3B] 3B shows a sidewall of the ion source of FIG. 3A. [Figure 4A] 1 shows a cross-sectional view of an ion source according to another embodiment. [Figure 4B] 4B shows the extraction plate of the ion source of FIG. 4A. [Figure 4C] 4B shows a sidewall of the ion source of FIG. 4A. [Figure 5A] 1 shows a cross-sectional view of an ion source according to a third embodiment. [Figure 5B] 5B shows the extraction plate of the ion source of FIG. 5A. [Figure 6A] 1 shows a cross-sectional view of an ion source according to a further embodiment; [Figure 6B] 1 shows a cross-sectional view of an ion source according to a further embodiment; [Figure 6C] 1 shows a cross-sectional view of an ion source according to a further embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0014] FIG. 1 shows a cross-sectional view of an IHC ion source 10 that can be used to extract a ribbon ion beam with improved height uniformity. The IHC ion source 10 includes a chamber 100 having two opposing ends and a wall 101 connecting the ends. These walls 101 include a side wall 101a, an extraction plate 103, and a bottom wall 101b opposite the extraction plate 103. Thus, the side wall 101a is adjacent to the extraction plate 103 along the width direction. In certain embodiments, the side wall 101a and the bottom wall 101b may be an integral component. The two opposing ends are adjacent to the extraction plate 103 along the height direction.

[0015] The extraction plate 103 has a height, width, and thickness. The extraction plate 103 includes an extraction aperture 140 that penetrates the extraction plate 103 in the thickness direction. Ions are extracted through the extraction aperture 140. The extraction aperture 140 may be significantly larger in the width direction (also called the X direction) than in the height direction (also called the Y direction). The Z direction is defined along the thickness of the extraction plate 103 and is defined as the direction of travel of the ribbon ion beam. For example, the extraction aperture 140 may be larger than 3 inches in the width direction and smaller than 0.3 inches in the height direction.

[0016] In certain embodiments, the extraction plate 103 may include a face plate 103a and an extraction liner 103b. The extraction liner 103b is disposed between the interior of the chamber 100 and the face plate 103a. The extraction liner 103b may be a replaceable part. In certain embodiments, the face plate 103a and the extraction liner 103b are both constructed from tungsten, although other suitable materials may be used.

[0017] The walls 101 of the chamber 100 may be constructed of a conductive material and may be in electrical communication with each other. A cathode 110 is disposed at the first end of the chamber 100. Department A cathode 110 is disposed within the chamber 100 at 104. A filament 160 is disposed behind the cathode 110. The filament 160 is in communication with a filament power supply 165. The filament power supply 165 is configured to pass a current through the filament 160, causing the filament 160 to emit thermal electrons. A cathode bias power supply 115 negatively biases the filament 160 with respect to the cathode 110. These thermal electrons are thus accelerated from the filament 160 toward the cathode 110, and when these thermal electrons strike the back surface of the cathode 110, they heat the cathode 110. The cathode bias power supply 115 may bias the filament 160 to have a voltage that is, for example, between 200 V and 1500 V more negative than the voltage of the cathode 110. The cathode 110 then emits thermal electrons from its front surface into the chamber 100.

[0018] Thus, the filament power supply 165 provides current to the filament 160. The cathode bias power supply 115 biases the filament 160, making it more negative than the cathode 110. As a result, electrons are attracted from the filament 160 toward the cathode 110. The filament 110 is in communication with the arc voltage power supply 111. The arc voltage power supply 111 provides a voltage to the cathode relative to the chamber 100. This arc voltage accelerates thermions emitted at the cathode into the chamber 100, ionizing the neutral gases. The current drawn by the arc voltage power supply 111 is a measure of the amount of current driven through the plasma 150. In certain embodiments, the wall 101 serves as a ground reference for other power supplies.

[0019] In this embodiment, a repeller 120 is located at the second end of the chamber 100 opposite the cathode 110. Department It is disposed in the chamber 100 at 105 .

[0020] The repeller 120 may be in electrical communication with a repeller power supply 123. As its name suggests, the repeller 120 serves to repel electrons emitted from the cathode 110 toward the center of the chamber 100. For example, in certain embodiments, the repeller 120 may be biased to a negative voltage with respect to the chamber 100 to repel the electrons. For example, in certain embodiments, the repeller 120 is biased between 0 and −150 V with respect to the chamber 100. In certain embodiments, the repeller 120 may be floating with respect to the chamber 100. In other words, when the repeller 120 is floating, it is not electrically connected to either the repeller power supply 123 or the chamber 100. In this embodiment, the voltage of the repeller 120 tends to drift to a voltage close to the voltage of the cathode 110. Alternatively, the repeller 120 may be electrically connected to the wall 101.

[0021] In certain embodiments, a magnetic field 190 is generated within the chamber 100. This magnetic field is intended to confine electrons along one direction. The magnetic field 190 typically has a first end Department 104 to the second end Department 105, parallel to wall 101. For example, electrons may be confined in columns parallel to the direction from cathode 110 to repeller 120 (i.e., the X direction). Therefore, electrons are not subjected to electromagnetic forces moving in the X direction. However, electrons moving in other directions may be subjected to electromagnetic forces.

[0022] One or more gas containers 108 may be in communication with the chamber 100 via gas inlets 106. Each gas container 108 may include a mass flow controller (MFC) 107 to regulate the flow rate of gas from each gas container.

[0023] The extraction power supply 170 can be used to bias the walls 101 of the IHC ion source 10 relative to the rest of the components in the beamline. For example, the platen 260 (see FIG. 2) can be at a first voltage, such as ground, while a positive voltage is applied to the IHC ion source 10 such that the IHC ion source 10 is biased more positively than the platen 260. Thus, the voltage supplied by the extraction power supply 170, referred to as the extraction voltage, determines the energy of the ions extracted from the IHC ion source 10. Furthermore, the current supplied by the extraction power supply 170 is a measure of the total extracted beam current.

[0024] In certain embodiments, a feedback loop exists between the cathode bias power supply 115 and the extraction power supply 170. In particular, it may be desirable to maintain the extracted beam current at a constant value. Therefore, the current provided by the extraction power supply 170 may be monitored, and the output of the cathode bias power supply 115 may be adjusted to maintain a constant extraction current. This feedback loop may be implemented by the controller 180, or may be implemented in another manner.

[0025] The controller 180 may be in communication with one or more of the power supplies, thereby monitoring and / or modifying the voltage or current provided by these power supplies. Additionally, the controller 180 may be in communication with the MFC 107 of each gas container 108 to regulate the flow rate of each gas into the chamber 100. 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 storage element, such as semiconductor memory, 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. For example, the controller 180 may be in communication with the cathode bias power supply 115 to enable the IHC ion source 10 to vary the voltage applied to the cathode relative to the filament 160. The controller 180 may also be in communication with the repeller power supply 123 to bias the repeller. Additionally, the controller 180 may monitor the voltage, current, and / or power provided by the cathode bias power supply 115 .

[0026] Figure 2 shows an ion implantation system that uses the IHC ion source 10 of Figure 1. One or more electrodes 200 are positioned outside and adjacent the extraction aperture of the IHC ion source 10.

[0027] Located downstream from the electrode 200 is a mass analyzer 210. The mass analyzer 210 uses a magnetic field to guide the path of the extracted ribbon ion beam 1. The magnetic field influences the flight path of the ions according to their mass and charge. A mass resolving device 220 having a resolving aperture 221 is located at the output (i.e., distal end) of the mass analyzer 210. By appropriately selecting the magnetic field, only those ions in the extracted ribbon ion beam 1 having a selected mass and charge will be guided through the resolving aperture 221. Other ions will collide with the walls of the mass resolving device 220 or the mass analyzer 210 and will not be able to travel further within the system.

[0028] A collimator 230 may be positioned downstream from the mass resolving device 220. The collimator 230 accepts ions from the extracted ribbon ion beam 1 that have passed through the resolving aperture 221 and generates a ribbon ion beam made up of multiple parallel or nearly parallel beamlets. The output (i.e., distal end) of the mass analyzer 210 and the input (i.e., proximal end) of the collimator 230 may be separated by a fixed distance. The mass resolving device 220 is positioned in the space between these two components.

[0029] An acceleration / deceleration stage 240 may be located downstream from the collimator 230. The acceleration / deceleration stage 240 may be referred to as an energy purity module. An energy purity module is a beamline lens component configured to independently control the deflection, deceleration, and focusing of the ion beam. For example, the energy purity module may be a vertical electrostatic energy filter (VEEF) or an electrostatic filter (EF). A platen 260 is located downstream from the acceleration / deceleration stage 240. A workpiece is placed on the platen 260 during processing.

[0030] The height of the extracted ribbon ion beam is improved by directing gas toward the extraction aperture 140. The gas flow serves to lower the height of the extracted beam. This can be achieved in several different ways.

[0031] In one embodiment, shown in FIGS. 3A-3B, the IHC ion source 10 can include a gas channel 141. The gas channel 141 terminates in a gas nozzle 142 located at or near the junction between the sidewall 101a and the extraction plate 103. FIG. 3A shows a cross-sectional view of the IHC ion source 10 according to this embodiment, while FIG. 3B shows the sidewall 101a of the ion source according to this embodiment. In this embodiment, as best seen in FIG. 3A, a feed gas is located in a gas vessel 108. The feed gas enters the chamber 100 through a gas inlet 106. The flow rate of the feed gas is controlled by an MFC 107. The gas inlet 106 can communicate with one or more feed channels 143 that deliver the feed gas to the interior of the chamber 100. In certain embodiments, the feed channel 143 can be located in the bottom wall 101b. In other embodiments, the feed channel 143 can be located in one or more of the sidewalls 101a.

[0032] Additionally, the gas inlet 106 may communicate with one or more gas channels 141 disposed inside the wall 101. For example, the gas channels 141 may be created by machining one or more channels in the side wall 101a. In another embodiment, the gas channels 141 may be created by providing tubes disposed along the inner or outer surface of the side wall 101a. In either embodiment, the gas is directed toward the end of the side wall 101a closest to the extraction plate 103.

[0033] In this embodiment, the gas channel 141 terminates at the upper surface of the sidewall 101a near the junction between the sidewall 101a and the extraction plate 103. The gas channel 141 may be disposed within the sidewall 101a. Thus, in this embodiment, as shown by arrows 144 in FIG. 3A , the supply gas exits the gas channel 141 through gas nozzles 142 within the sidewall 101a and flows along the inner surface of the extraction plate 103 before reaching the extraction openings 140. For example, as shown in FIG. 3B , multiple gas nozzles 142 may be disposed on the inner surface of the sidewall 101a on both sides of the extraction plate 103, where the extraction plate 103 contacts the sidewall 101a. The gas channel 141 terminates at the upper surface of the sidewall 101a within horizontal grooves 146 extending along the sidewall 101a in the X direction. Each of the gas nozzles 142 communicates with one of the horizontal grooves 146. Additionally, the size of each gas nozzle 142 may be the same in some embodiments. In other embodiments, the gas nozzles 142 may vary and be sized based on the amount of height adjustment to be performed. For example, if the height of the extracted ribbon ion beam 1 is highest at the center of the extraction aperture 140, the gas nozzles 142 aligned with the center of the extraction aperture 140 may be larger than the other gas nozzles 142. In this manner, more gas will flow through these larger nozzles, suppressing the extracted ribbon ion beam 1. Note that in this embodiment, the extraction plate 103 does not vary.

[0034] It should be noted that if a tube is used to carry the feed gas along the inner or outer surface of the side wall 101 a, the tube may terminate in the horizontal groove 146 .

[0035] In a related embodiment, there may be no feed channel 143. In this embodiment, the feed gas to be ionized enters through a gas nozzle 142.

[0036] Figures 4A-4C show a second embodiment: Figure 4A shows a cross-sectional view of an IHC ion source 10 according to this embodiment, Figure 4B shows an extraction liner 103b according to this embodiment, and Figure 4C shows a sidewall 101a of the ion source according to this embodiment.

[0037] In this embodiment, as best seen in FIG. 4A , a feed gas is disposed in a gas vessel 108. The feed gas enters the chamber 100 through a gas inlet 106. The flow rate of the feed gas is controlled by an MFC 107. The gas inlet 106 may communicate with one or more feed channels 143 that deliver the feed gas to the interior of the chamber 100. In certain embodiments, the feed channel 143 may be disposed in the bottom wall 101 b. In other embodiments, the feed channel 143 may be disposed in one or more of the side walls 101 a.

[0038] Additionally, the gas inlet 106 may communicate with one or more gas channels 141 disposed inside the wall 101. For example, the gas channels 141 may be created by machining one or more channels in the side wall 101a. In another embodiment, the gas channels 141 may be created by providing tubes disposed along the inner or outer surface of the side wall 101a. In either embodiment, the gas is directed toward the end of the side wall 101a closest to the extraction plate 103.

[0039] In this embodiment, the gas flow passages 141 terminate at the upper surface of the sidewall 101a near the junction between the sidewall 101a and the extraction plate 103. The gas channels 141 may be disposed within the sidewall 101a. As shown in FIG. 4C, the gas channels 141 terminate at the upper surface of the sidewall 101a in horizontal grooves 146 that extend along the X direction.

[0040] In this embodiment, as shown in FIG. 4B , the horizontal grooves in the sidewall 101a communicate with corresponding horizontal plate grooves 147 in the extractor plate 103. The horizontal plate grooves 147 communicate with plate gas channels 145 disposed in the extractor plate 103. In certain embodiments, the horizontal plate grooves 147 and the plate gas channels 145 are disposed in the extractor liner 103b. The horizontal plate grooves 147 can be disposed to overlap the horizontal grooves 146 in the sidewall 101a when assembled. In this manner, the gas channels 141 in the sidewall 101a supply feed gas to the horizontal grooves 146 coupled to the horizontal plate grooves 147. The feed gas then enters the plate gas channels 145 in the extractor plate 103. The feed gas then exits the plate gas channels 145 through gas nozzles 142. The gas nozzles 142 are disposed on the inner surface of the extractor plate 103 near the extraction openings 140, such as within 0.25 inches. In some embodiments, the gas nozzles 142 may be positioned within 0.1 inches of the extraction aperture 140. In this embodiment, the gas nozzles 142 are closer to the extraction aperture 140 than the embodiment shown in Figures 3A-3B and may be more effective in shaping the extracted ribbon ion beam 1. The dimensions of the various gas nozzles 142 may be as described above.

[0041] It should be noted that if a tube is used to carry the feed gas along the inner or outer surface of the side wall 101 a, the tube may terminate in the horizontal groove 146 or the horizontal plate groove 147 .

[0042] In a related embodiment, there may be no feed channel 143. In this embodiment, the feed gas to be ionized enters through a gas nozzle 142.

[0043] 5A-5B show another embodiment. FIG. 5A shows a cross-sectional view of the IHC ion source 10, while FIG. 5B shows the extraction liner 103b. In this embodiment, as shown in FIG. 5A, the extraction liner 103b is formed such that a gap 148 exists between the top surface of the sidewall 101a and the faceplate 103a. Holes 149 in the extraction liner 103b allow fluid communication between the gas channels 141 and the gap 148.

[0044] The gaps 148 communicate with a plurality of plate gas channels 145 disposed within the extraction liner 103b. In this embodiment, the horizontal grooves 146 may not be present. Rather, the gas channels 141 may be aligned with the holes 149 to allow the feed gas to flow directly into the gaps 148. Other aspects of this embodiment may be similar to those described with respect to the embodiment shown in Figures 4A-4B.

[0045] 3A, 4A, and 5A all show the gas channel 141 and the supply channel 143 communicating with the same gas inlet 106. However, in other embodiments, there may be two gas inlets, in which case the flow rate of gas entering each gas inlet may be independently controlled using a separate mass flow controller (MFC) 107. In this manner, the flow rate of gas introduced near the extraction aperture 140 may not be related to the flow rate of the supply gas used for ionization.

[0046] Figures 6A to 6C show three embodiments with separated gas inlets, which correspond to the embodiments of Figures 3A, 4A and 5A, respectively.

[0047] As described above, the flow rate of gas from the gas reservoir 108 is controlled by the MFC 107. The gas then passes through the gas inlet 106 and enters the gas channels 141. In FIG. 6A, the gas channels 141 terminate near the junction between the sidewall 101a and the extractor plate 103, as described above in connection with FIG. 3A. In FIG. 6B, the plate gas channels 145 are located within the extractor plate 103, as described above in connection with FIG. 4A. In FIG. 6C, the plate gas channels 145 are located within the extractor liner 103b, as described above in connection with FIG. 5A.

[0048] However, in these embodiments, a second gas inlet 116 is used to supply a feed gas to the chamber 100. Specifically, the feed gas may be stored in a second gas container 118. The flow rate of the feed gas is controlled by a second MFC 117. The feed gas enters through the second gas inlet 116. The second gas inlet 116 is in communication with the feed channel 143. Thus, the flow rates of the gas through the two gas inlets may be controlled separately.

[0049] In these embodiments, the gas channels 141 and the supply channels 143 are completely separated, such that there is no fluid communication between the supply channels 143 and the gas channels 141.

[0050] 6A-6C show two different gas containers, it should be understood that one gas container can be in communication with both MFCs such that gas from a single gas container is used to supply gas to both supply channel 143 and gas channel 141. In other words, MFC 107 can be used to regulate the flow rate of gas through gas nozzle 142, while a second MFC 117 is used to independently control the flow rate of supply gas into chamber 100 through supply channel 143. In this manner, the two flow rates can be separately controlled and optimized for their respective functions.

[0051] In certain embodiments, the use of two separate gas inlets allows for the use of two different gases. For example, a feed gas may be provided in a second gas container 118. A shielding gas, different from the feed gas, may be stored in the gas container 108. The shielding gas may be an inert species such as argon or xenon.

[0052] 6A-6C show the feed channel 143 located in the bottom wall 101b of the ion source, it should be understood that the location of the feed channel 143 may be varied. For example, the feed channel 143 may enter the chamber 100 through the side wall 101a.

[0053] The ion source described above is an IHC ion source. However, other ion sources can also be used with the gas nozzle 142. For example, magnetized DC plasma sources, tubular cathode sources, Bernas ion sources, and inductively coupled plasma (ICP) ion sources can also use gas channels and gas nozzles. Thus, the extraction plate can be used with ion sources having a variety of different plasma generators.

[0054] During operation, gas, which may be a supply gas for the embodiments shown in FIGS. 3A, 4A, and 5A or a shield gas for the embodiments shown in FIGS. 6A-6C, may be supplied to gas channel 141. The gas travels through gas channel 141 and exits through gas nozzle 142. Gas flowing near extraction aperture 140 tends to compress the ribbon ion beam being extracted through extraction aperture 140. To improve the uniformity of the height of the extracted ion beam, its flow rate may be different in different portions of extraction aperture 140 along the X direction. For example, a larger gas nozzle may be employed in the region where the extracted ion beam height is traditionally greatest. In some embodiments, such as those shown in FIGS. 6A-6C, the flow rate of gas through gas nozzle 142 may be adjusted using MFC 107 independently of the flow rate of the supply gas, which is controlled by second MFC 117.

[0055] This system has many advantages. The ability to flow gas (either supply gas or shield gas) near the extraction aperture can facilitate shaping of the ribbon ion beam being extracted. Specifically, the ion flow can be compressed in the height direction. Conventionally, ribbon ion beams extracted from ion sources can be non-uniform in height as a result of the plasma geometry and chemistry inside the ion source. By compressing or blocking a portion of the ion flow to account for the general non-uniform profile, a more uniform ribbon ion beam can be extracted in the height direction.

[0056] The present disclosure is not limited in scope by the specific embodiments described herein. Indeed, various other embodiments and modifications of the present disclosure, in addition to those described herein, will be apparent to those skilled in the art from the foregoing description and accompanying drawings. Accordingly, such other embodiments and modifications are intended to be included within the scope of the present disclosure. Moreover, while the present disclosure has been described herein in the context of particular implementations in particular environments for particular purposes, those skilled in the art will recognize that its utility is not limited thereto, and that the present disclosure may be beneficially implemented in any number of environments for any number of purposes. Accordingly, the claims set forth below should be construed in accordance with the broadest possible scope and spirit of the disclosure as described herein.

Claims

1. An ion source comprising: a chamber having a first end, a second end, and a plurality of walls connecting the first end and the second end, one of the walls being an extraction plate having an extraction opening with a width greater than a height; a plasma generator for generating a plasma within the chamber; a gas inlet in communication with the gas channel; a supply channel in communication with the gas inlet for supplying a feed gas to the chamber; and a gas nozzle disposed within the chamber near the extraction opening and communicating with the gas channel to provide a flow of the supply gas near the extraction opening for shaping the ion beam extracted from the ion source. An ion source comprising:

2. The ion source of claim 1 , wherein the plurality of walls includes a bottom wall opposite the extraction plate and a side wall adjacent the extraction plate, the gas channel being disposed within the side wall.

3. 2. The ion source of claim 1, wherein the plurality of walls include a bottom wall opposite the extraction plate and a side wall adjacent the extraction plate, and the gas channel includes a tube disposed proximate an inner or outer surface of the side wall.

4. 10. The ion source of claim 1, further comprising a plate gas channel disposed in the extraction plate and communicating with the gas channel, the gas nozzle being disposed on an inner surface of the extraction plate proximate the extraction opening.

5. 2. The ion source of claim 1, wherein the plurality of walls include a bottom wall opposite the extraction plate and a side wall adjacent the extraction plate, and the gas nozzle is disposed on an inner surface of the side wall adjacent the extraction plate.

6. 2. The ion source of claim 1, wherein the extraction plate comprises a face plate and an extraction liner disposed between the interior of the chamber and the face plate, the extraction liner being configured such that a gap exists between the extraction liner and the face plate, the gap communicating with the gas channel, the ion source further comprising a plate gas channel disposed within the extraction liner and communicating with the gap, and the gas nozzle is disposed on a surface of the extraction liner proximate to the extraction opening.

7. The ion source of claim 1 , wherein the gas nozzle dimensions vary along the width of the extraction aperture to improve height uniformity of the extracted ribbon ion beam.

8. The ion source of claim 1 , wherein the plasma generator comprises an indirectly heated cathode (IHC).

9. 10. The ion source of claim 1 . mass spectrometer, and An ion implantation system comprising a platen.

10. An ion source comprising: a chamber having a first end, a second end, and a plurality of walls connecting the first end and the second end, one of the plurality of walls being an extraction plate having an extraction opening with a width greater than a height; a plasma generator for generating a plasma within the chamber; a gas inlet in communication with the gas channel; a gas nozzle located within the chamber near the extraction opening and in communication with the gas channel for shaping an ion beam extracted from the ion source; and a second gas inlet in communication with the supply channel for supplying a supply gas to the chamber; Equipped with The ion source, wherein the supply channel and the gas channel are not in fluid communication with each other.

11. The ion source of claim 10 , wherein the plurality of walls include a bottom wall opposite the extraction plate and a side wall adjacent the extraction plate, the gas channel being disposed within the side wall.

12. 11. The ion source of claim 10, wherein the plurality of walls include a bottom wall opposite the extraction plate and a side wall adjacent the extraction plate, and the gas channel includes a tube disposed proximate an inner or outer surface of the side wall.

13. 11. The ion source of claim 10, further comprising a plate gas channel disposed in the extraction plate and communicating with the gas channel, the gas nozzle being disposed on an inner surface of the extraction plate proximate the extraction opening.

14. 11. The ion source of claim 10, wherein the plurality of walls include a bottom wall opposite the extraction plate and a side wall adjacent the extraction plate, and the gas nozzle is disposed on an inner surface of the side wall proximate the extraction plate.

15. 11. The ion source of claim 10, wherein the extraction plate comprises a face plate and an extraction liner disposed between the interior of the chamber and the face plate, the extraction liner being configured such that a gap exists between the extraction liner and the face plate, the gap communicating with the gas channel, the ion source further comprising a plate gas channel disposed within the extraction liner and communicating with the gap, and the gas nozzle is disposed on a surface of the extraction liner proximate to the extraction opening.

16. The ion source of claim 10 , further comprising a first gas container in fluid communication with the gas inlet and a second gas container in fluid communication with the second gas inlet.

17. 11. The ion source of claim 10, further comprising a gas container in fluid communication with a first mass flow controller and a second mass flow controller, wherein the first mass flow controller controls a flow rate through the gas inlet and the second mass flow controller controls a flow rate through the second gas inlet, and wherein the flow rates through the gas inlet and the second gas inlet are controlled independently.

18. The ion source of claim 10 , wherein the gas nozzle dimensions vary along the width of the extraction aperture to improve height uniformity of the extracted ribbon ion beam.

19. The ion source of claim 10 , wherein the plasma generator comprises an indirectly heated cathode (IHC).

20. 11. The ion source of claim 10. mass spectrometer, and An ion implantation system comprising a platen.

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