GAS SUPPLY SYSTEM FOR ION IMPLANTS

Abstract

Ion implantation system (100) comprising: an ion implanter (102) comprising an ion source unit (120); and a dopant source gas supply system (104) comprising: a dopant source gas storage tank (132, 132a-c) inside a gas box container (130) located spatially separate from the ion implanter (102); and a dopant source gas supply line (140) configured to supply a dopant source gas from the dopant source gas storage tank (132, 132a-c) to the ion source unit (120), the dopant source gas supply line (140) comprising: an inner tube (144); an outer tube (146) enclosing the inner tube (144); a first tube adapter (150a) coupled to a first end of both the inner tube (144) and the outer tube (146), the first tube adapter (150a) connecting the inner tube (144) to the dopant source gas storage tank (132, 132a-c);and a second pipe adapter (150b) coupled to a second end of both the inner pipe (144) and the outer pipe (146) opposite the first end, the second pipe adapter (150b) connecting the inner pipe (144) to the ion source unit (120); a control unit (108); a shut-off valve (134) coupled to the dopant source gas storage tank (132) to control the supply of the dopant source gases from the dopant source gas storage tank (132) to the ion source unit (120) of the ion implanter (102); and a monitoring system (106) comprising a current measuring device (166) installed between the dopant source gas supply line (140) and earth, configured to detect a current signal and trigger the control unit (108) to close the shut-off valve (134).

Description

BACKGROUND Ion implantation is a process for incorporating chemical species into a substrate by directly bombarding the substrate with energetic ions. In semiconductor manufacturing, ion implantation is commonly used to incorporate dopants into a semiconductor wafer to modify its electronic properties. Ion implantation is performed in an ion implanter. An ion implanter contains an ion source unit for generating positively charged ion species. These ion species are extracted from the ion source unit by a high-voltage extraction potential and then filtered to obtain the desired ion species—that is, an ion species intended to impact a target, such as a target region on a semiconductor wafer. The desired ion species are further accelerated and directed toward the target for implantation. US Patent 6,515,290 B1 discloses a gas supply system for ion implanters. An insulating supply line is arranged between a first gas box and a second gas box at different voltage potentials, which conducts ion source gases between the gas boxes. The insulating supply line comprises an inner tube for the ion source gases and an outer tube that can be filled with an inert gas. US patent 6,180,954 B1 discloses a double-walled tube for the outlet line of a vacuum pump used in an ion implanter. A relatively thin inner tube has ribs and is arranged within a thicker-walled, cylindrical outer tube. The cylindrical shape of the outer tube protects and supports the shape and length of the inner ribbed tube, thus providing increased robustness to the structure. US Patent 5,935,374 A discloses a device for manufacturing electronic devices comprising a reaction chamber; a cathode and anode electrode opposite each other in the reaction chamber; a gas inlet tube inserted into the reaction chamber for supplying reaction gas that is electrically connected to the cathode; and a high-frequency power generation device for driving the cathode with a high excitation frequency in the VHF or UHF band through the gas inlet tube to bring the reaction gas into a plasma state. The gas inlet tube includes an impedance matching device. BRIEF DESCRIPTION OF THE DRAWINGS Aspects of the present disclosure are best understood with reference to the following detailed description, when read together with the accompanying figures. It should be noted that, in accordance with common industry practice, various features are not drawn to scale. Rather, the dimensions of the various features may be enlarged or reduced as necessary for the sake of clarity of discussion. Fig. 1 is a schematic representation of an ion implantation system according to some embodiments. Fig. 2A is a perspective view of a dopant source gas supply line used in a dopant source gas supply system in the ion implantation system according to some embodiments. Fig. 2B is a cross-sectional view of the dopant source gas supply line of Fig. 2A along line B-B'.Figure 3 is a flowchart of a method for supplying a dopant source gas to an ion implanter of the ion implantation system according to some embodiments. Figure 4 is a block diagram of a control unit for controlling the operation of the ion implantation system. DETAILED DESCRIPTION An improved ion implantation system according to the invention is provided according to claims 1 and 13. The following disclosure provides many different embodiments or examples for implementing various features of the subject matter discussed herein. Specific examples of components, values, operations, materials, arrangements, or the like are described below to simplify the present disclosure. Other components, values, operations, materials, arrangements, or the like are also considered.For example, forming a first feature over or on top of a second feature in the following description may include embodiments in which the first and second features are in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, so that the first and second features are not necessarily in direct contact. Furthermore, this disclosure may repeat reference numerals and / or letters in the various examples. This repetition is for the sake of simplicity and clarity and does not automatically establish a relationship between the various embodiments and / or configurations discussed. Typical dopant species used in ion implantation for the fabrication of silicon-based integrated circuits are boron as a p-dopant and phosphorus or arsenic as an n-dopant. Dopant species are generated from dopant source gases, such as boron trifluoride (BF3), phosphorus (PH3), and arsenic (AsH3). These dopant source gases are highly toxic, and to prevent factory personnel from being exposed to them, gas cylinders for supplying the dopant source gases are usually placed in a gas box. The gas box is located within an enclosure containing the ion implanter. The gas box is an enclosure connected to the ion source unit and operates at the same high voltage when the ion implanter is in operation. Small gas cylinders must be used to fit within the limited space inside the ion implanter housing. The cylinders containing the toxic / hazardous doping source gases must be frequently replaced with fresh cylinders filled with the same gases. Performing such a cylinder exchange, which involves cylinders located inside the gas locker, requires technicians to wear self-contained breathing apparatus (SCBA), physically remove the used cylinders, and install fresh ones. This poses significant safety concerns regarding the handling of these doping source gas cylinders. In addition to the hazards associated with changing gas cylinders inside the ion implanter housing, it is also common for the gas cylinders to become depleted during production, necessitating a shutdown of the ion implantation system to perform the cylinder change. Such unscheduled shutdowns of the ion implanter can result in costly rework of partially processed wafers, and in some cases, the wafer products may be defective or even unusable for their intended purpose as a consequence of the interruption in processing. In embodiments of the present disclosure, an ion implantation system is provided that includes a dopant source gas supply system configured to supply one or more dopant source gases to an ion implanter from a location spatially remote from the ion implanter. Placing the dopant source gas supply system outside the housing containing the ion implanter helps to reduce the space required for the ion implanter. Furthermore, placing the dopant source gas supply system outside the housing of the ion implanter allows the use of larger gas storage tanks, thereby reducing the frequency of replacing the empty gas tanks in which the gases are consumed. This improves the operational efficiency of the ion implantation system.The ion implantation system also features a monitoring system configured to detect any leakage of dopant source gases from the dopant source gas supply lines, with the dopant source gas storage tanks being able to be coupled to the ion source unit. The ion implantation system thus offers increased safety in the event of a dopant source gas leak. Fig. 1 is a schematic representation of an ion implantation system 100 according to some embodiments. As shown in Fig. 1, the ion implantation system 100 comprises an ion implanter 102 configured to perform ion implantation processes on a semiconductor wafer, a dopant source gas supply system 104 configured to supply one or more dopant source gases to the ion implanter 102, and a monitoring system 106 configured to monitor the escape of a dopant source gas during the ion implantation processes. The ion implantation system 100 is communicatively coupled to a control unit 108. Components of the ion implantation system 100 receive control signals from the control unit 108 and perform various operations based on the received control signals. The ion implanter 102 is housed in a casing 110. In some versions, the ion implanter 102 includes an ion source unit 120, a mass analyzer unit 122, an ion accelerator unit 124, and a terminal station 126. The ion implanter 102 is configured to generate an ion beam 128, send the ion beam 128 towards the terminal station 126, and direct the ion beam 128 onto a workpiece, for example, a semiconductor wafer, at the terminal station 126. The ion source unit 120 is configured to ionize a dopant source gas to form ions. The ion source unit 120 generates ions by introducing electrons into a vacuum arc chamber filled with the dopant source gas. Collisions of the electrons with atoms and molecules in the dopant source gas result in the formation of an ionized plasma consisting of positive and negative ions. The generated ions are extracted from the ion source unit 120 by applying a high voltage to form the ion beam 128. To generate the ion beam 128, the ion source unit 120 is held at a high positive potential to generate and extract the generated ions. In some embodiments, the ion source unit 120 is held at an electrical potential of, for example, approximately 5 kV to approximately 250 kV relative to ground potential.In some embodiments, the ion source unit 120 is located at an electrical potential of 90 kV relative to the ground potential. The mass analyzer unit 122 is positioned along the beam path between the ion source unit 120 and the terminal station 126. The mass analyzer unit 122 has a curved internal passage and one or more magnets arranged along this internal passage. When the ion beam 128 enters the internal passage of the mass analyzer unit 122, it is bent by the magnetic field of the magnets. As a result, ions in the ion beam 128 with a charge-to-mass ratio outside a predefined range are deflected into the side walls of the internal passage, while selected ions in the ion beam 128 with a charge-to-mass ratio within the predefined range are allowed to exit the mass analyzer unit 122. The ion accelerator unit 124 is configured to apply an accelerating voltage to the ion beam 128 after the ion beam 128 has left the mass analyzer unit 122, thereby accelerating the ion beam 128 to a desired implantation energy before it reaches the final station 126. In embodiments, the accelerating voltage is adjusted in a range of approximately 50 kV to approximately 250 kV. The terminal station 126 is located at the end of the beam path. The terminal station 126 is configured to receive the ion beam 128 and direct it onto a semiconductor wafer. In some embodiments, the terminal station 126 includes a chuck (not shown) for holding the semiconductor wafer and an actuator (not shown) for moving the chuck with the semiconductor wafer held thereon in one or more directions. The movements of the chuck are configured such that the ion beam 128 strikes the semiconductor wafer uniformly. In some embodiments, the terminal station 126 includes a loading port for transferring the semiconductor wafer into or out of the ion implanter 102 and a robotic arm for transferring the semiconductor wafer between the chuck and the loading port.In some embodiments, the terminal station 126 further comprises a measuring device for measuring one or more properties of the ion beam 128 to be directed at the semiconductor wafer, thereby providing feedback information for adjusting the ion beam 128 according to a processing recipe to be applied to the semiconductor wafer. Examples of measured ion beam properties include a beam profile, beam energy, and beam current. The dopant source gas supply system 104 is designed to supply various types of dopant source gases in parallel to the ion source unit 120 of the ion implanter 102, enabling easy switching between the dopant source gases (for example, to allow easy switching from an n-type dopant to a p-type dopant). For example, a gaseous hydride such as arsine (AsH3) or phosphine (PH3) is typically used as a dopant source gas for an n-type dopant, while a gaseous fluoride such as boron difluoride is typically used as a dopant source gas for a p-type dopant. All of these dopant source gases are toxic and corrosive and require appropriate handling. In some embodiments, the doping source gas supply system 104 originates from a source located spatially remote from the ion implanter 102. In some embodiments, the source is a sealed gas container 130 containing several doping source gas storage tanks 132. The doping source gas storage tanks 132 are designed to store different types of doping source gases and supply them to the ion source unit 120 of the ion implanter 102. For the safety of factory personnel, the gas container 130 and the doping source gas storage tanks 132 arranged therein are kept at a ground potential (for example, 0 V) ​​or a low potential during operation of the ion implantation system 100. In some embodiments, the dopant source gas storage tanks 132 comprise a first dopant source gas storage tank 132a, designed to supply a first dopant source gas to the ion source unit 120 of the ion implanter 102; a second dopant source gas storage tank 132b, designed to supply a second dopant source gas to the ion source unit 120 of the ion implanter 102; and a third dopant source gas storage tank 132c, designed to supply a third dopant source gas to the ion source unit 120 of the ion implanter 102. It should be noted that, although the dopant source gas supply system 104 of Fig. 1 illustrates a system that accomplishes the supply of three (3) different types of dopant source gases, systems that supply more or fewer dopant source gases are also being considered.In some embodiments, the first dopant source gas is an arsenic-containing gas, such as AsH3, the second dopant source gas is a phosphorus-containing gas, such as PH3, and the third dopant source gas is a boron-containing gas, such as BF3. Shut-off valves 134 are coupled to respective dopant source gas storage tanks 132 (for example 132a, 132b, 132c) to control the supply of dopant source gases from respective dopant source gas storage tanks 132 (for example 132a, 132b, 132c) to the ion source unit 120 of the ion implanter 102.For example, in some embodiments, a first shut-off valve 134a is coupled to the first dopant source gas storage tank 132a to control the supply of the first dopant source gas from the first dopant source gas storage tank 132a to the ion source unit 120 of the ion implanter 102, a second shut-off valve 134b is coupled to the second dopant source gas storage tank 132b to control the supply of the second dopant source gas from the second dopant source gas storage tank 132b to the ion source unit 120 of the ion implanter 102, and a third shut-off valve 134c is coupled to the third dopant source gas storage tank 132c to control the supply of the third dopant source gas from the third dopant source gas storage tank 132c to the ion source unit 120 of the ion implanter 102. To control the ion implanter 102.Each of the shut-off valves 134 (for example, 134a, 134b and 134c) is normally closed and opens when a corresponding dopant source gas is supplied to the ion source unit 120 of the ion implanter 102 when the ion implantation system 100 is in operation. The dopant source gas supply system 104 further comprises several dopant source gas supply lines 140 for transporting the dopant source gas from the respective dopant source gas storage tanks 132 (for example, 132a, 132b, and 132c) to the ion source unit 120. Because each of the dopant source gas supply lines 140 has a similar configuration and operates in a similar manner, for the sake of simplicity and brevity, only a single dopant source gas supply line 140 is illustrated in Fig. 1, which connects the dopant source gas storage tank 132a to the ion source unit 120. In some embodiments, the dopant source gas supply line 140 begins on the outside of the gas container 130 and terminates at a control box 141, which is located inside the housing 110.In some embodiments, the control box 141 includes a mass flow controller (not shown) designed to control the amount of dopamine source gas flowing into the ion source unit 120 of the ion implanter 102. The dopamine source gas supply line 140 thus extends across a potential difference between the gas box reservoir 130 and the ion source unit 120 of the ion implanter 102. In some embodiments, there is a potential difference of 90 kV between the opposite ends of the dopamine source gas supply line 140. Figures 2A and 2B illustrate a dopant source gas supply line 140 from Figure 1. Figure 2A is a perspective view of the dopant source gas supply line 140 according to some embodiments. Figure 2B is a cross-sectional view of the dopant source gas supply line 140 from Figure 2A along line B-B'. As shown in Figures 2A and 2B, the dopant source gas supply line 140 in some embodiments comprises a pipe body 142 and pipe adapters (150a, 150b) coupled to opposite ends of the pipe body 142. In some embodiments, the tube body 142 has a double-walled tube structure. The tube body 142 comprises two separate tubes, an inner tube 144 transporting the dopant source gas from a dopant source gas storage tank 132 (for example, 132a, 132b, or 132c), and an outer tube 146 transporting an inert gas, such as nitrogen or argon. The outer tube 146 surrounds the inner tube 144 and has a diameter larger than that of the inner tube 144. In some embodiments, the inner tube 144 and the outer tube 146 are circular. However, it should be noted that any shapes for the inner tube 144 and the outer tube 146, such as a hexagonal shape and an oval shape, are acceptable. In some embodiments, the outer tube 146 is filled with an inert gas at a predetermined pressure, and the pressure change of the inert gas inside the outer tube 146 is monitored. Consequently, a leak in the dopant source gas supply line 140 can be detected if the pressure change of the inert gas in the outer tube 146 falls below a predetermined threshold. Furthermore, the pressure of the inert gas in the outer tube 146 is maintained at a higher value than the pressure of the dopant source gas in the inner tube 144. Therefore, if a leak occurs in the inner tube 144, the dopant source gas is contained within it. The outer tube 146 thus provides a safe containment in the event of a leak in the inner tube 144. During operation of the ion implantation system 100, the dopant source gas is routed to the ion source unit 120 via the dopant source gas supply line 140. Inside the housing 110 of the ion implanter 102, the dopant source gas is raised from ground potential to a potential at which the ion source unit 120 operates. In some embodiments, the ion source unit 120 operates at 90 kV. Consequently, the dopant source gas supply line 140 must bridge a potential difference to transport dopant source gas from a dopant source gas storage tank 132 (for example, 132a, 132b, or 132c) to the ion source unit 120.To isolate the ion source unit 120 from the electrical ground of the gas storage tank 130, the inner tube 144 and the outer tube 146 of the tube body 142 are made of an electrically insulating material, such as polytetrafluoroethylene (PTFE), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), or a ceramic material, such as aluminum oxide. The insulating tube material helps to maintain the potential difference between the dopamine source gas storage tank 132 (for example, 132a, 132b, or 132c) and the ion source unit 120 during operation of the ion implantation system 100. In some embodiments, to provide the tube body 142 with sufficient mechanical strength, grooves are formed on the outer surface of both the inner tube 144 and the outer tube 146 of the tube body 142. In embodiments according to the invention, the grooves are formed along the outer circumference of both the inner tube 144 and the outer tube 146 of the tube body 142. The first pipe adapter 150a and the second pipe adapter 150b are connected to the front and rear ends of the pipe body 142, respectively. The first pipe adapter 150a is configured to seal the front end of the pipe body 142 and to connect the front end of the pipe body 142 to a dopant source gas storage tank 132 (for example, 132a, 132b, or 132c). In some embodiments, the first pipe adapter 150a comprises an inner cap 152a configured to couple to the front end of the inner tube 144 of the pipe body 142, and an outer cap 154a configured to couple to the front end of the outer tube 146 of the pipe body 142. In some embodiments, the first pipe adapter 150a further comprises an inlet port 156a which extends through the outer cap 154a and the inner cap 152a to be in flow communication with the inner tube 144 of the pipe body 142.The inlet port 156a is configured to allow dopant source gas from a dopant source gas storage tank 132 (for example, 132a, 132b, or 132c) to flow into the inner tube 144 of the tube body 142. The first tube adapter 150a further includes an inlet port 158, which extends through the outer cap 154a to be in flow communication with the outer tube 146 of the tube body 142. The inlet port 158 ​​is configured to allow an inert gas to be pumped into the outer tube 146 of the tube body 142, for example, via an inert gas line 160. The second tube adapter 150b is configured to seal the rear end of the tube body 142 and to connect the rear end of the tube body 142 to the ion source unit 120 of the ion implanter 102. In some embodiments, the second tube adapter 150b comprises an inner cap 152b configured to couple to the rear end of the inner tube 144 of the tube body 142, and an outer cap 154b configured to couple to the rear end of the outer tube 146 of the tube body 142. In some embodiments, the second tube adapter 150b comprises an outlet port 156b extending through the outer cap 154b and the inner cap 154b to be in flow communication with the inner tube 144 of the tube body 142.The outlet port 156b is configured to allow the dopant source gas flowing into the inner tube 144 of the tube body 142 to flow out of the dopant source gas supply line 140 and into the ion source unit 120 of the ion implanter 102. The second pipe adapter 150b is held at a higher potential than the first pipe adapter 150a because the second pipe adapter 150b is connected to an electrically conductive gas transport line 162, which is coupled to the ion source unit 120 of the ion implanter 102. In some embodiments, the first pipe adapter 150a and the second pipe adapter 150b are made of an electrically conductive material, such as stainless steel. The monitoring system 106 is configured to monitor for a leak in the dopant source gas supply line 140 in place. In some embodiments, the monitoring system 106 includes a pressure sensor 164 that is in flow communication with the inert gas line 160. The pressure sensor 164 is designed to detect the pressure level of the inert gas contained in the outer tube 146 of the dopant source gas supply line 140 at any point during the operation of the ion implantation system 100. By monitoring the pressure level of the inert gas in the outer tube 146, a leak is detected when the pressure of the inert gas decreases, for example, when the pressure of the inert gas falls below a previously defined threshold.If it is detected that the inert gas pressure falls below the previously defined threshold, the control unit 108 sends a control signal to close the corresponding shut-off valve 134 (for example, 134a, 134b, or 134c) and thereby isolate the associated dopant source gas storage tank 132 (for example, 132a, 132b, or 132c). This prevents the safety problem caused by the release of the toxic dopant source gas into the atmosphere due to a leak in the dopant source gas supply line 140. In some embodiments, the monitoring system 106 further comprises a current measuring device 166, which is installed between the dopant source gas supply line 140 and ground. The current measuring device 166 is designed to detect a current signal. During normal operation of the ion implantation system 100, the current detected by the current measuring device 166 is zero or below the background noise. If an event occurs, such as an arc or discharge due to a leak in the dopant source gas supply line 140, the current measuring device 166 detects a current signal and triggers the control unit 108 to close the corresponding shut-off valve 134 (for example, 134a, 134b, or 134c). Fig. 3 is a flowchart of a method 300 for supplying a dopant source gas to an ion implanter 102 of an ion implantation system 100 from Fig. 1 according to some embodiments. One or more components of the ion implantation system 100 are controlled by the control unit 108 (Fig. 5) to carry out the method 300. The procedure 300 includes operation 302, in which an outer tube 146 of a dopant source gas supply line 140 is filled with an inert gas (for example, nitrogen) having a previously determined pressure. In operation 304 of procedure 300, a dopant source gas from a dopant source gas storage tank 132 (for example, 132a, 132b, 132c) is supplied to an ion source unit 120 of the ion implanter 102. The dopant source gas from the dopant source gas storage tank 132, which is at a ground potential, is supplied to the ion source unit 120 of the ion implanter 102, which operates at a higher potential (for example, about 90 kV), via an inner pipe 144 of the dopant source gas supply line 140. In operation 306 of procedure 300, the pressure of the inert gas contained in the outer tube 146 of the dopant source gas supply line 140 is monitored in place using a pressure sensor 164 while the dopant source gas flows from the dopant source gas storage tank 132 to the ion source unit 120 of the ion implanter 102. In operation 308 of procedure 300, a leak in the dopant source gas supply line 140 is detected. In cases where the dopant source gas supply line 140 is leaking, the pressure level of the inert gas in the outer tube 146 of the dopant source gas supply line 140 drops. The pressure value of the inert gas in the outer tube 146 of the dopant source gas supply line 140 is sent to the control unit 108 and compared with a previously defined pressure threshold. As soon as the pressure of the inert gas falls below the previously defined pressure threshold, an alarm is triggered to report the leak in the dopant source gas supply line 140. Otherwise, the dopant source gas continues to be transported through the dopant source gas supply line 140 to the ion source unit 120 of the ion implanter 102. If a leak is detected in the dopant source gas supply line 140, procedure 300 proceeds to operation 310. In operation 310, in response to the alarm indicating the occurrence of the leak in the dopant source gas supply line 140, the supply of the dopant source gas is interrupted. For example, as soon as the control unit 108 detects that the dopant source gas supply line 140 is leaking, the control unit 108 sends a control signal to a corresponding shut-off valve 134 (for example, 134a, 134b, or 134c). The corresponding shut-off valve 134 (for example 134a, 134b or 134c) is closed to stop the gas flow from the associated dopant source gas storage tank 132 (for example 132a, 132b or 132c) to the ion source unit 120 of the ion implanter 102. In Operation 312, the factory personnel are informed, and the defective doping source gas supply line 140 is replaced. Fig. 4 is a block diagram of the control unit 108 for controlling the operation of the ion implantation system 100 according to some embodiments. In some embodiments, the control unit 108 is a general-purpose computer device comprising a hardware processor 402 and a non-volatile, computer-readable storage medium 404, which is encoded with, i.e., stores, a computer program code, that is, a set of executable instructions 406. The computer-readable storage medium 404 is also encoded with instructions 406 for communication with components of the ion implantation system 100, for example, the ion implanter 102 and the dopant source gas supply system 104. The processor 402 is electrically coupled to the computer-readable storage medium 404 via a bus 408. The processor 402 is also electrically coupled to an I / O interface 410 via the bus 408. A network interface 412 is also electrically connected to the processor 402 via a bus 408.The network interface 412 is connected to a network 414, enabling the processor 402 and the computer-readable storage medium 404 to connect to external elements via the network 414. The processor 402 is configured to execute the computer program instructions 406 encoded in the computer-readable storage medium 404 in order to make the control unit 108 available for the complete or partial execution of the operations described in the procedure 300. In some embodiments, the 402 processor is a central processing unit (CPU), a multiprocessor, a distributed processing system, an application-specific integrated circuit (ASIC) and / or a suitable processing unit. In some embodiments, the computer-readable storage medium 404 is an electronic, magnetic, optical, electromagnetic, infrared, and / or semiconductor system (or such device or apparatus). For example, the computer-readable storage medium 404 includes a semiconductor or solid-state memory, a magnetic tape, a removable computer disk, random-access memory (RAM), read-only memory (ROM), a rigid magnetic disk, and / or an optical disk. In some embodiments operating with optical disks, the computer-readable storage medium 404 includes a compact disc read-only memory (CD-ROM), a compact disc read / write (CD-R / W), and / or a digital video disc (DVD). In some embodiments, the computer-readable storage medium 404 stores the computer program instructions 406, which are configured to cause the control unit 108 to execute the method 300 in whole or in part. In some embodiments, the computer-readable storage medium 404 also stores information required for carrying out the method 300, as well as information generated during the execution of the method 300, such as pressure sensor parameters 416 and / or a set of executable instructions for performing one or more operations of the method 300. In some embodiments, the computer-readable storage medium 404 stores the computer program instructions 406 for connecting to the ion implantation system 100. The computer program instructions 406 enable the processor 402 to generate operating instructions that can be read by components in the ion implanter 102, the dopant source gas supply system 104, and the monitoring system 106 in order to effectively perform the operations described with respect to the ion implanter 102, the dopant source gas supply system 104, and the monitoring system 106. The control unit 108 includes the input / output interface (I / O interface) 410. The I / O interface 410 is coupled to external circuitry. In some embodiments, the I / O interface 410 includes a keyboard, keypad, mouse, trackball, trackpad, and / or cursor direction keys for transmitting information and commands to the processor 402. The control unit 108 also includes a network interface 412, which is coupled to the processor 402. The network interface 412 enables the control unit 108 to communicate with the network 414, to which one or more other computer systems are connected. The network interface 412 includes wireless network interfaces such as Bluetooth, Wi-Fi, WiMAX, GPRS, or WCDMA, or wired network interfaces such as Ethernet, USB, or IEEE-1394. In some embodiments, the operations as described in relation to method 300 are implemented in two or more control units 108, and information, such as refracted light intensities and one or more intensity thresholds, is exchanged between different control units 108 via the network 414. The advantages and features of the disclosure become even clearer with reference to the following exemplary embodiments: One aspect of this description relates to an ion implantation system. In some embodiments, an ion implantation system comprises an ion implanter having an ion source unit and a dopant source gas supply system. The dopant source gas supply system comprises a dopant source gas storage tank inside a gas cylinder located spatially separate from the ion implanter, and a dopant source gas supply line configured to deliver dopant source gas from the dopant source gas storage tank to the ion source unit. The dopant source gas supply line comprises an inner tube, an outer tube enclosing the inner tube, a first tube adapter coupled to a first end of both the inner tube and the outer tube, and a second tube adapter coupled to a second end of both the inner tube and the outer tube opposite the first end. The first tube adapter connects the inner tube to the dopant source gas storage tank, and the second tube adapter connects the inner tube to the ion source unit. The ion implantation system comprises a control unit, a shut-off valve coupled to each dopant source gas storage tank to control the supply of dopant source gases from the respective tank to the ion source unit of the ion implanter, and a monitoring system comprising a current-measuring device installed between the dopant source gas supply line and ground, configured to detect a current signal and trigger the control unit to close the corresponding shut-off valve. In some embodiments, both the inner and outer tubes have multiple grooves on their outer surface. In some embodiments, both the inner and outer tubes contain an electrically insulating material.In some embodiments, both the inner and outer tubes contain polytetrafluoroethylene, polypropylene, polyethylene, or polyvinyl chloride. In some embodiments, both the first and second tube adapters contain an electrically conductive material. In some embodiments, both the first and second tube adapters contain stainless steel. In some embodiments, the first tube adapter comprises an inner cap that seals the first end of the inner tube and an outer cap that seals the first end of the outer tube. In some embodiments, the first tube adapter also comprises a first port that is in flow communication with the inner tube and a second port that is in flow communication with the outer tube.In some embodiments, the first port extends through the inner and outer caps of the first tube adapter, and the second port extends through the outer cap of the first tube adapter. In some embodiments, the second tube adapter includes an inner cap that seals the second end of the inner tube and an outer cap that seals the second end of the outer tube. In some embodiments, the second tube adapter also includes a third port that is in flow communication with the inner tube. In some embodiments, the third port extends through the inner and outer caps of the second tube adapter. Another aspect of this description concerns an ion implantation system. In some embodiments, an ion implantation system comprises an ion implanter inside a housing and includes an ion source unit. The ion implantation system further includes a dopamine source gas storage tank inside a gas cylinder located outside the housing. The ion implantation system also includes a dopamine source gas supply line configured to deliver dopamine source gas from the dopamine source gas storage tank to the ion source unit.The dopamine source gas supply line comprises an inner tube configured to carry the dopamine source gas, an outer tube enclosing the inner tube and configured to carry an inert gas, a first tube adapter coupled to a first end of both the inner and outer tubes and connecting the inner tube to the dopamine source gas storage tank, and a second tube adapter coupled to a second end of both the inner and outer tubes opposite the first end, connecting the inner tube to the ion source unit. The ion implantation system further comprises a pressure sensor configured to measure the pressure level of the inert gas in the outer tube. In some embodiments, both the inner and outer tubes contain an electrically insulating material.The ion implantation system comprises a control unit, a shut-off valve coupled to a respective dopant source gas storage tank to control the supply of dopant source gases from the respective dopant source gas storage tank to the ion source unit of the ion implanter, and a monitoring system comprising a current measuring device installed between the dopant source gas supply line and earth, configured to detect a current signal and trigger the control unit to close the corresponding shut-off valve.In some embodiments, the first pipe adapter comprises an inner cap that seals the first end of the inner pipe, an outer cap that seals the first end of the outer pipe, a first inlet port extending through the inner and outer caps to connect with the inner pipe, and a second inlet port extending through the outer cap to connect with the outer pipe. In some embodiments, the second pipe adapter comprises an inner cap that seals the second end of the inner pipe, an outer cap that seals the second end of the outer pipe, and an outlet port extending through the inner and outer caps to connect with the inner pipe. In some embodiments, both the first and second pipe adapters are made of stainless steel.In some embodiments, both the inner and outer tubes have multiple grooves on their outer surface. In some embodiments, the gas cylinder is at ground potential. Another aspect of this description concerns a method for using an ion implantation system. In some embodiments, the method includes filling an outer tube of an adjuvant source gas supply line with an inert gas having a predetermined pressure. The method further includes supplying an adjuvant source gas from an adjuvant source gas storage tank to an ion source unit of an ion implanter via an inner tube of the adjuvant source gas supply line, which is surrounded by the outer tube. The ion implanter is arranged in a housing, and the adjuvant source gas storage tank is arranged in a gas cylinder located outside the housing. The method further includes monitoring the inert gas pressure in place. The method further includes detecting a leak in the adjuvant source gas supply line when the pressure of the inert gas falls below a predetermined threshold.In some embodiments, the method further includes stopping the supply of the dopant source gas by closing a shut-off valve connected to the dopant source gas storage tank.

Claims

Ion implantation system (100) comprising: an ion implanter (102) comprising an ion source unit (120); and a dopant source gas supply system (104) comprising: a dopant source gas storage tank (132, 132a-c) inside a gas box container (130) located spatially separate from the ion implanter (102); and a dopant source gas supply line (140) configured to supply a dopant source gas from the dopant source gas storage tank (132, 132a-c) to the ion source unit (120), the dopant source gas supply line (140) comprising: an inner tube (144); an outer tube (146) enclosing the inner tube (144); a first tube adapter (150a) coupled to a first end of both the inner tube (144) and the outer tube (146), the first tube adapter (150a) connecting the inner tube (144) to the dopant source gas storage tank (132, 132a-c);and a second pipe adapter (150b) coupled to a second end of both the inner pipe (144) and the outer pipe (146) opposite the first end, the second pipe adapter (150b) connecting the inner pipe (144) to the ion source unit (120); a control unit (108); a shut-off valve (134) coupled to the dopant source gas storage tank (132) to control the supply of the dopant source gases from the dopant source gas storage tank (132) to the ion source unit (120) of the ion implanter (102); and a monitoring system (106) comprising a current measuring device (166) installed between the dopant source gas supply line (140) and earth, configured to detect a current signal and trigger the control unit (108) to close the shut-off valve (134). Ion implantation system (100) according to claim 1, wherein both the inner tube (144) and the outer tube (146) comprise an electrically insulating material. Ion implantation system (100) according to claim 2, wherein both the inner tube (144) and the outer tube (146) comprise polytetrafluoroethylene, polypropylene, polyethylene or polyvinyl chloride. Ion implantation system (100) according to one of claims 1 to 3, wherein both the first tube adapter (150a) and the second tube adapter (150b) comprise an electrically conductive material. Ion implantation system (100) according to claim 4, wherein both the first tube adapter (150a) and the second tube adapter (150b) comprise stainless steel. Ion implantation system (100) according to any one of claims 1 to 5, wherein the first tube adapter (150a) comprises an inner cap (124b, 152a, 152b) that seals the first end of the inner tube (144) and an outer cap (154a, 154b) that seals the first end of the outer tube (146). Ion implantation system (100) according to claim 6, wherein the first tube adapter (150a) further comprises a first port (156a) which is in flow communication with the inner tube (144) and a second port (158) which is in flow communication with the outer tube (146). Ion implantation system (100) according to claim 7, wherein the first port (156a) extends through the inner cap (124b, 152a, 152b) and the outer cap (154a, 154b) of the first tube adapter (150a) and the second port (158) extends through the outer cap (154a, 154b) of the first tube adapter (150a). Ion implantation system (100) according to any one of claims 1 to 8, wherein the second tube adapter (150b) comprises an inner cap (124b, 152a, 152b) that seals the second end of the inner tube (144) and an outer cap (154a, 154b) that seals the second end of the outer tube (146). Ion implantation system (100) according to claim 9, wherein the second tube adapter (150b) further comprises a third port (156b) in flow connection with the inner tube (144). Ion implantation system (100) according to claim 10, wherein the third port (156b) extends through the inner cap (124b, 152a, 152b) and the outer cap (154a, 154b) of the second tube adapter (150b). Ion implantation system (100) according to one of claims 1 to 11, wherein both the inner tube (144) and the outer tube (146) comprise multiple grooves on their outer surface. Ion implantation system (100) comprising: an ion implanter (102) inside a housing (110), wherein the ion implanter (102) comprises an ion source unit (120); a dopamine source gas storage tank (132, 132a-c) inside a gas box container (130) located outside the housing (110); a dopamine source gas supply line (140) configured to supply a dopamine source gas from the dopamine source gas storage tank (132, 132a-c) to the ion source unit (120), wherein the dopamine source gas supply line (140) comprises: an inner tube (144) configured to transport the dopamine source gas; an outer tube (146) enclosing the inner tube (144) and configured to transport an inert gas;a first tube adapter (150a) coupled to a first end of both the inner tube (144) and the outer tube (146), wherein the first tube adapter (150a) connects the inner tube (144) to the dopant source gas storage tank (132, 132a-c); and a second tube adapter (150b) coupled to a second end of both the inner tube (144) and the outer tube (146) opposite the first end, wherein the second tube adapter (150b) connects the inner tube (144) to the ion source unit (120); and a pressure sensor (164) configured to measure a pressure level of the inert gas in the outer tube (146), a control unit (108), a shut-off valve (134) coupled to the dopant source gas storage tank (132) to control the supply of the dopant source gases from the dopant source gas storage tank (132) to the ion source unit (120) of the ion implanter (102);and a monitoring system (106) comprising a current measuring device (166) installed between the doping source gas supply line (140) and earth and configured to detect a current signal and trigger the control unit (108) to close the shut-off valve (134). Ion implantation system (100) according to claim 13, wherein both the inner tube (144) and the outer tube (146) comprise multiple grooves on their outer surface. Ion implantation system (100) according to claim 13 or 14, wherein both the inner tube (144) and the outer tube (146) comprise an electrically insulating material. Ion implantation system (100) according to one of claims 13 to 15, wherein the first tube adapter (150a) comprises an inner cap (124b, 152a, 152b) that seals the first end of the inner tube (144), an outer cap (154a, 154b) that seals the first end of the outer tube (146), a first inlet port (156a) that extends through the inner cap (124b, 152a, 152b) and the outer cap (154a, 154b) to be in flow communication with the inner tube (144), and a second inlet port (158) that extends through the outer cap (154a, 154b) to be in flow communication with the outer tube (146). Ion implantation system (100) according to one of claims 13 to 16, wherein the second tube adapter (150b) comprises an inner cap (124b, 152a, 152b) that seals the second end of the inner tube (144), an outer cap (154a, 154b) that seals the second end of the outer tube (146), and an outlet port (156b) that extends through the inner cap (124b, 152a, 152b) and the outer cap (154a, 154b) to be in flow communication with the inner tube (144). Ion implantation system (100) according to one of claims 13 to 17, wherein both the first tube adapter (150a) and the second tube adapter (150b) comprise an electrically conductive material. Ion implantation system (100) according to one of claims 13 to 18, wherein the gas cylinder container (130) is at an earth potential.

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