An apparatus and method for reducing particle contamination by a bias voltage

Abstract

The present invention provides a bias voltage to a component (such as a Faraday cup) to reduce particle generation and prevent particle stripping from the component. The particles can be implanted ions and / or the combination of implanted ions and component materials. The intensity of the bias voltage must not significantly affect the ion implantation of the wafer and must also significantly block the radiation and / or electrons emitted from the biased component. There is no limitation on how to provide and adjust the bias voltage, and both an additional voltage source and a modified preamplifier are feasible. Further, since the bias voltage changes the electric field generated by the Faraday cup, the convergence of the ion beam adjacent to the Faraday cup is reduced, thereby minimizing the possible difference between the ion beam measured by the analyzer and the ion beam received by the Faraday cup.

Description

Technical Field

[0001] The present invention relates to improvements in ion implanters and ion implantation, and particularly to improvements in reducing particle contamination by using a bias voltage in low-energy ion implantation. Background Art

[0002] Ion implantation technology has been widely used to manufacture modern products such as integrated circuits, volatile or non-volatile memories, flat panel displays, and solar cells, etc. Therefore, there is a strong need to continuously improve the structure of ion implanters to be suitable for different ion implantation processes.

[0003] In recent years, the demand for low-energy ion implantation has been continuously increasing, such as ion implantation with an ion energy lower than 1000 electron volts (eV). Such a demand has led to a more critical need: to prevent particle contamination of internal components (internal component) being bombarded by ions. For example, the internal components can be a Faraday cup, a chuck, or electrodes and magnets configured to adjust the ion beam. Generally, the ion implantation depth is proportional to the ion energy of the ions to be implanted. For this reason, the reduced energy of the implanted ions in low-energy ion implantation also reduces the implantation depth of the implanted ions. Compared with high-energy ion implantation in which ions with higher energy but the same dose are distributed from the surface of the internal component to its deeper interior, the implanted ions in low-energy ion implantation will accumulate massively on the surface or shallower part of the internal component. Fixed and repeated low-energy ion implantation will result in more and more ions being deposited on the surface or shallower part of this component. Therefore, when the ion beam continuously bombards this component, these accumulated debris will easily peel off from the component during the next low-energy ion implantation. Even after the low-energy ion implantation stops, these peelings will still continue to occur. The peeled and existing debris may drift into or enter the interior of the process chamber and cause particle contamination. Therefore, there is an urgent need to reduce or eliminate the debris peeling off from the internal component during the low-energy ion implantation process. Summary of the Invention

[0004] In one embodiment, the present invention reduces the problem of particle contamination by using a new configuration in which internal components are bombarded by an ion beam. The internal components can be a Faraday cup configured to receive the ion beam, a chuck configured to hold a wafer, or electrodes, magnets, and a plasma flow gun configured to adjust the ion beam. These internal components are prone to being bombarded by ions during the ion implantation process. Among these internal components, the Faraday cup can accumulate the largest number and highest concentration of particles because the ion beam frequently bombards it during the ion implantation process. When there is only a short or close distance between the Faraday cup and the wafer held by the chuck, the particle contamination will be exacerbated.

[0005] In one embodiment, the present invention reduces the problem of particle contamination by applying a bias voltage to the internal components bombarded (or interacting with) by the ion beam, particularly to the plate in the Faraday cup designed to directly receive the ion beam. Reasonably, the applied bias voltage increases the implantation energy of the ions after they pass through the plane where the chuck is located. These ions with increased energy are strongly conducted to the biased plate that is bombarded. Accordingly, the distribution of these ions can penetrate deeper into these plates in the Faraday cup. Therefore, the particles formed on the surface or shallower part of these plates can be effectively reduced, and the combination of the implanted ions and the internal component material can also be avoided. It must be emphasized that the applied bias voltage must be limited so that the implantation energy of the ions implanted into the wafer is basically not affected because the wafer held by the chuck is placed near the Faraday cup. Similarly, the applied bias voltage should also be limited so that when the ideal condition of the ion beam is to be conducted through the adjacent area of this component, the conduction of the ion beam is basically not affected. Incidentally, the applied bias voltage may also attract these particles to some extent. Accordingly, the probability of particle peeling off from any internal component can be reduced, and the particle contamination in the vacuum environment inside the ion implanter can also be reduced correspondingly.

[0006] In a commercially available ion implanter, the potential energy of the Faraday cup is maintained at a voltage reference point (i.e., 0 volts) to ensure accurate measurement of the ion beam current of the ion beam received by the Faraday cup. This configuration is basically excellent when the implanted ions are distributed from the flat surface to the deep inner part of the flat plate of the Faraday cup. However, when low-energy ion implantation processes are applied, especially when they have become common in recent years, such a configuration will inevitably face particle contamination. In particular, when low-energy ion implantation processes are carried out, these particles will accumulate on the surface or the shallower part of these flat plates in the Faraday cup. On the contrary, the present invention applies a bias voltage to these flat plates in the Faraday cup so that the implanted ions are distributed from the surface of these flat plates to their deep parts. It should be noted that the ion implantation energy of the ions implanted into the wafer is not changed by the bias voltage applied to the Faraday cup. Instead, the ions passing through the planes of both the chuck and the analyzer and conducted to the Faraday cup will be accelerated and their energy will be correspondingly changed at this stage. Accordingly, the present invention can more efficiently prevent particle contamination and there will be no obvious side effects either.

[0007] Generally speaking, the intensity of the bias voltage can be inversely proportional to the ion beam energy because the implantation depth of the implanted ions is proportional to the ion beam energy, and the intensity of the bias voltage is proportional to the ion beam current because the concentration of the implanted ions is proportional to the ion beam current. Incidentally, the polarity of the bias voltage can be opposite to the polarity of the implanted ions, or it can be opposite to the polarity of the particles formed on the surface / inside of the implanted component. Of course, the quantitative adjustment of the bias voltage depends at least on the ion beam and the component that can be implanted by the ion beam (or that will interact with the ion beam). In other words, the quantitative adjustment of the bias voltage is case-by-case.

[0008] It must be emphasized that the intensity of the bias voltage must be properly controlled to ensure that the ion implantation of the wafer held by the chuck near the Faraday cup can be correctly carried out, and to ensure that the ion beam can be properly conducted from the ion source to both the wafer and the Faraday cup. Thereby, any side effects without positive benefits can be avoided. In particular, the intensity of the bias voltage must be properly controlled to reduce the emission of radiation and / or electrons and not release other charged particles.

[0009] In addition, the present invention does not limit how to provide and adjust this bias voltage. For example, it can be achieved by simply connecting a required voltage source to the plate of the Faraday cup. Or, if it is necessary to calibrate the output voltage of the voltage source to conform to the required bias voltage, a calibration circuit can be selectively used. Or it can also be achieved by adjusting the hardware / software of the preamplifier and the controller used in a commercial Faraday cup, where the controller can be a programmable multi-axis controller and an input-and-output controller.

[0010] Furthermore, by applying a bias voltage, the present invention can adjust the path of ions passing through the reaction chamber and suppress the divergence of ions. Thereby, the ions passing through the reaction chamber are suppressed, redirected, and received by the Faraday cup, and the portion of the ion beam that is not received by the Faraday cup after passing through the position where the wafer will be implanted is significantly reduced. A main reason is that the applied bias voltage changes the electric field near the Faraday cup, and the profile of the Faraday cup also causes the spatial intensity distribution of the electric field near the edge of the Faraday cup to have more intensity variations than the electric field far from the edge of the Faraday cup. Thereby, the generation and change of the electric field contribute to more accurate measurement by the Faraday cup. It should be noted that the applied bias voltage accelerates the speed of ions conducted to the vicinity of the Faraday cup, that is, it increases the implantation energy of ions implanted into these plates of the Faraday cup, and does not change the ion beam energy before the ion beam is conducted through the position where the wafer will be implanted. Description of the Drawings

[0011] After reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings, the above features and advantages of the present invention can be better understood. In the drawings, the components are not necessarily drawn to scale, and components having similar relevant characteristics or features may have the same or similar reference numerals.

[0012] Figure 1A 、 1B show how both the ion implantation depth and the ion implantation concentration vary with different ion beam energies;

[0013] Figure 2A 、 2B Figures 2C and 2D show the operation of a conventional Faraday cup after low-energy ion implantation and the particle distribution in a vacuum environment;

[0014] Figure 3A 、 3B, the operation of the Faraday cup proposed for 3C and 3D displays after low-energy ion implantation and the particle distribution in a vacuum environment;

[0015] Figure 4A , 4B , 4C is an example of a possible configuration for applying a bias voltage to a commercially available Faraday cup;

[0016] Figure 5 is a computer simulation of the equipotential contour distribution caused by the bias voltage applied to the Faraday cup;

[0017] Figure 6A , 6B is a cross-sectional view schematically showing the shape of a ribbon ion beam in a vacuum environment of a conventional Faraday cup in the first (long) dimension and the second (short) dimension;

[0018] Figure 7A , 7B is a cross-sectional view schematically showing the shape of a ribbon ion beam in a vacuum environment of a biased Faraday cup in the first (long) dimension and the second (short) dimension;

[0019] Figure 8A , 8B is a schematic comparison of the change in the ion beam shape between a conventional Faraday cup and a biased Faraday cup.

[0020] Reference numerals:

[0021] 201: Faraday cup

[0022] 202: Reaction chamber wall

[0023] 203: Ion beam

[0024] 204: Chuck

[0025] 205: Wafer

[0026] 206: Analyzer

[0027] 207: Particle

[0028] 301: Faraday cup

[0029] 302: Reaction chamber wall

[0030] 303: Ion beam

[0031] 304: Chuck

[0032] 305: Wafer

[0033] 306: Analyzer

[0034] 307: Particle

[0035] 308: Voltage source

[0036] 400: Reaction chamber

[0037] 401: Faraday cup

[0038] 402: Reaction chamber wall

[0039] 403: Voltage reference point

[0040] 404: Controller

[0041] 405: Preamplifier

[0042] 406: Calibration circuit

[0043] 408: Voltage source

[0044] 501: Faraday cup

[0045] 501A: Faraday cup opening

[0046] 600: Reaction chamber

[0047] 601: Faraday cup

[0048] 603: Beam-like ion beam

[0049] 700: Processing chamber

[0050] 701: Faraday cup

[0051] 703: Beam-like ion beam

[0052] 709: A certain part

[0053] 801A: Faraday cup

[0054] 803: Beam-like ion beam

[0055] 803a: Ion beam

[0056] 803b: Ion beam

[0057] 806: Analyzer

[0058] 808: Bias voltage Detailed implementation mode

[0059] The physical mechanism of the problem to be solved by the present invention can be abstractly described as follows. The ion implantation depth (doping depth) is proportional to the ion beam energy (doping energy), and the ion implantation concentration (doping concentration) is correspondingly proportional to the ion implantation current. Refer to Figures 1A to 1BHow the shown ion implantation depth and ion implantation concentration vary with different ion beam energies. Reasonably, when the energy of the ion beam is low enough, the distribution of implanted ions will be concentrated heavily near the surface of the implanted component. Therefore, not only will the shallower part of the implanted component be strongly damaged due to the presence of a large number of implanted ions, but also a certain number of particles will be stripped from the implanted component and float into the vacuum environment where the wafer is held for ion implantation. For example, the stripped particles can be the implanted ions themselves or a combination of both the implanted ions and the material of the implanted component. Thus, particle contamination phenomenon will inevitably occur inside the ion implanter.

[0060] With the increasing demand for low-energy ion implantation, some experiments in recent years have demonstrated that such particle contamination phenomenon may deteriorate rapidly as the ion beam energy decreases from thousands of electron volts to hundreds of electron volts. For example, some experiments have shown that ion implantation with an ion beam energy between 200 electron volts and 500 electron volts will have a significantly increased particle contamination. The particle contamination phenomenon is more severe inside the Faraday cup facing the vacuum environment because it is adjacent to the wafer held by the electrostatic chuck and because the ion beam continuously impacts the Faraday cup during ion implantation. In addition, such particle contamination may also become apparent in other parts of the vacuum environment inside the ion implanter because the ion beam sometimes hits off the electrodes / magnets, plasma gun, or mass analyzer during the ion beam adjustment cycle.

[0061] Figures 2A to 2D Describe how particle contamination occurs and why it deteriorates more in the vacuum environment adjacent to the Faraday cup in commercially available ion implanters. Figure 2A Schematically depict the end station incorporating the Faraday cup 201 in a commercially available ion implanter. As Figure 2A shown, the Faraday cup 201 is embedded in the reaction chamber wall 202 of the ion implanter and faces the ion beam 203. Both the chuck 204 configured to hold the wafer 205 to be implanted and the profiler 206 configured to monitor the ion beam dose are placed in the same plane perpendicular to the ion beam 203. The chuck 204 moves back and forth along this plane, and the profiler 206 also moves along this plane to detect the ion beam current. For simplicity of illustration, the Faraday cup 201 is presented as a cup-shaped structure, where the bottom and side walls of the cup-shaped structure correspond to the multiple plates configured to receive the ion beam 203. The circuit configured to measure and analyze the current of the received ion beam is omitted. As Figure 2BAs shown, when the suction cup 204 and the wafer 205 move back and forth along a scanning direction, the ion beam 203 is intermittently conducted into the Faraday cup 201 every interval time. Therefore, the ion beam 203 is not blocked by the wafer 205 (or the suction cup 204) and the analyzer 206, and directly hits the Faraday cup 201 every interval time. As Figure 2C shown, during ion implantation, according to the mechanism discussed above, a large number of particles 207 are formed on and inside the inner surface of the Faraday cup 201. As Figure 2D shown, during and after ion implantation, a part of these particles 207 will peel off from the inner surface of the Faraday cup 201. The peeled debris can diffuse or float into the vacuum environment surrounded by the reaction chamber wall 202, and can even move to the suction cup 204, the wafer 205 and / or the analyzer 206, and then cause some corresponding damage to these components.

[0062] Figures 3A to 3D Describe how particle contamination is prevented and why there is no significant particle contamination in the Faraday cup 301 facing the vacuum environment of the processing chamber. Figure 3A Schematically depict a terminal station incorporating a Faraday cup 301 configured according to an embodiment of the present invention. Figure 3B and Figure 3C depict the formation and distribution of some particles 307 during ion implantation. Note that Figure 3A 、 Figure 3B and Figure 3C are respectively substantially similar to Figure 2A 、 Figure 2B and Figure 2C , except for the presence of a voltage source 308 configured to provide a bias voltage to the Faraday cup 301. During ion implantation, according to the mechanism discussed above, some particles 307 are formed on and / or inside the inner surface of the Faraday cup 301. Due to the application of the bias voltage source 308, the number of these particles 307 is significantly less than the number of those particles 207 as Figure 2D shown, because the applied bias voltage can increase the implantation energy of these ions implanted into the Faraday cup 301 and distribute these implanted ions to a deeper part of the Faraday cup 301. Incidentally, the applied bias voltage can somewhat attract these particles 307 adjacent to the Faraday cup 301 and further prevent these particles 307 from floating or migrating back to the reaction chamber. Figure 3D is a summary diagram showing the results of particle contamination after using the configuration of the present invention. By comparing Figure 3D and Figure 2D, it can be found that only a small amount of particles 307 are formed on the surface inside the Faraday cup 301. In other words, by applying a bias voltage to bias the Faraday cup 301 as proposed in the present invention, particle contamination is effectively prevented because only a small portion of the particles 307 or even no particles 307 can be stripped away from the inner surface of the Faraday cup 301. Accordingly, the particles or debris floating or migrating into the vacuum environment surrounded by the reaction chamber wall 302 can be greatly reduced. Accordingly, the number of particles moving to the chuck 304, the wafer 305, and / or the analyzer 306 is effectively reduced.

[0063] For example, Figure 4A Briefly depicts a simplified configuration of a reaction chamber 400 and a Faraday cup 401 in an ion implanter using the biased Faraday cup of the present invention. In this embodiment, the Faraday cup 401 is biased to a negative voltage, and this negative bias voltage can range from several hundred negative volts to negative several thousand volts. Moreover, a chuck and an analyzer (such as a sensor) are placed in the vacuum environment surrounded by the reaction chamber wall 402 and can be moved therein and held at a voltage reference point (i.e., grounded / 0 volts).

[0064] In some embodiments, the analyzer can be a microchannel plate, a camera, or a similar sensor, so that parameters such as ion beam intensity, ion beam current, ion beam cross-sectional area, and ion beam image can be determined. Accordingly, the analyzer can be configured to provide information about the ion beam, such as whether the ion beam is properly conducted, and to allow monitoring of the ion beam associated with the ion implantation system. In some embodiments, the analyzer of this system includes multiple sensors. For example, the analyzer can include both a microchannel plate and a camera, and thus can simultaneously determine the ion beam current and the ion beam image, which can be further used to adjust the ion beam as needed.

[0065] Figure 4C A sample of providing a bias voltage to the Faraday cup is presented. Figure 4B Corresponding to an existing commercial ion implanter and briefly depicting a circuit configured to match the Faraday cup and analyze the received ion beam. In Figure 4B , a pre-amplifier (pre-AMP) 405 is electrically coupled to the Faraday cup 401 and the voltage reference point (voltage zero) GND respectively. The measured results of the received ion beam are transmitted to a controller (such as PMAC&IOC) 404. Conversely, Figure 4CCorresponding to the Faraday cup 401 improved using the present invention and schematically depicting the configuration to match the Faraday cup 401 with the circuit for analyzing the received ion beam. The voltage source 408 is electrically coupled to the Faraday cup 401, the calibration circuit 406, and the voltage reference point 403 respectively, and the preamplifier 405 is electrically coupled to the calibration circuit 406 and the controller 404 respectively. Clearly, the voltage source 408 is configured to apply the required bias voltage to the Faraday cup 401 and the calibration circuit 406 is configured to adjust the operation of the preamplifier 405, thereby eliminating the effect of the bias voltage on the measured voltage of the received ion beam. In this way, the signals transmitted to the controller 404 are not affected by the use of the voltage source 408.

[0066] In any case, the present invention does not limit how the bias voltage is provided. For example, in an embodiment not shown, the voltage source is discarded and a calibration circuit with a built-in database is applied. This built-in database records the relationship between how a reference voltage is applied to the Faraday cup and the correction of the operation of the preamplifier according to previous experiments / simulations. In this way, the required biased Faraday cup can also be achieved, and the ion beam current received by the proposed biased Faraday cup can also be correctly measured. Similarly, in some embodiments not shown, other internal components in the ion implanter can also be simply biased by using a voltage source because the functions of these internal components are not related to receiving and measuring the ion beam.

[0067] In addition, the intensity of the applied bias voltage depends at least on the actual design of these components (especially the Faraday cup) and the actual operation of the ion implantation. It must be high enough to prevent the formation of these particles and prevent these particles from peeling off from this component, thereby eliminating or preventing particle contamination. In addition, it must be adequately regulated or adjusted to avoid the emission of radiation and / or charged particles (such as electrons) from the Faraday cup, thereby preventing any unwanted side effects. For example, it must be low enough to prevent the risk of harm to the operator of the ion implanter from the emitted radiation. Depending on the recipe used in the ion implanter, the bias voltage should not exceed a certain threshold to affect or change the recipe or the ion beam path conducted in the vacuum environment.

[0068] Significantly, the bias voltage applied to the Faraday cup automatically changes the electric field distributed in the adjacent vacuum environment. Figure 5 Computer simulation of the equipotential contour distribution caused by the bias voltage applied to the Faraday cup 501. As Figure 5As shown, near the opening of the Faraday cup 501, especially at the edge of the opening of the Faraday cup, these equipotential contours are densely distributed and rapidly decrease from high potential energy to low equipotential energy. Conversely, far from the Faraday cup 501, these equipotential contours are sparsely distributed and slowly decrease from high potential energy to low equipotential energy. In particular, at the opposite part of the opening 501A of the Faraday cup, the distribution of these equipotential contours gradually decreasing from higher potential energy to lower potential energy is in a bubble-like shape. According to Figure 5 the simulation results shown, the ion beam path is correspondingly modified by the bias voltage applied to the Faraday cup 501 because the direction of the electric field is perpendicular to each of these equipotential lines. In particular, due to the distribution of these equipotential contours, any ions conducted to the vicinity of the opening 501A of the Faraday cup will be drawn into the middle of the opening 501A of the Faraday cup. In addition, any ions conducted to the outer side adjacent to the opening 501A of the Faraday cup can be deflected and drawn into the inner space surrounded by the Faraday cup 501. Therefore, the ions in the broad beam of ions being transmitted to the Faraday cup 501 can be reshaped into a narrower beam of ions to be received by the biased Faraday cup 501.

[0069] Figure 6A and Figure 6B are cross-sectional views of a beam of ions reaching the Faraday cup 601 held at a potential reference point (i.e., no bias voltage is applied) through the reaction chamber 600. Figure 6A is a cross-sectional view seen from the first dimension (major axis) of the ion beam 603, while Figure 6B is a cross-sectional view seen from the second dimension (minor axis) of the ion beam 603. As Figure 6A and Figure 6B show, the Faraday cup 601 is held at a potential reference point, and the energy of the ion beam 603 is held at a positive voltage regardless of whether it is inside the processing chamber 600 or entering the Faraday cup 601. From the processing chamber 600 to the bottom of the Faraday cup 601, the profile and direction of the ion beam 603 are basically maintained the same, although the space-charge effect may cause a small divergence of the ion beam.

[0070] Figure 7A and Figure 7B are schematic cross-sectional views of a beam of ions 703 reaching the Faraday cup 701 through the processing chamber 700. Figure 7A and Figure 7B are similar to Figure 6A andFigure 6B , except that a negative bias voltage is applied to the Faraday cup 701. In this embodiment, the Faraday cup 701 is maintained at the required negative bias voltage. The ion beam 703 passing through the processing chamber 700 is thus accelerated by the bias voltage, and the potential energy of the ions implanted into the bottom of the Faraday cup 701 is adjusted to -1 volt. Due to the change in potential energy and the attraction of the negative bias voltage applied to the Faraday cup 701, in Figure 7A and Figure 7B a certain part 709, the shape of the ion beam 703 is substantially changed or narrowed. The convergence and reshaping of the beam-like ion beam in the first and second dimensions can ensure a more accurate measurement of the total ion beam current of the ion beam 703.

[0071] The benefits of the present invention are not limited to preventing particle contamination, because the biased Faraday cup can narrow or change the ion beam shape as Figure 8B shown. Figure 8A Schematically shows a beam-like ion beam 803, an analyzer 806, and an unbiased Faraday cup 801A. Figure 8B Similar to Figure 8A , except that a bias voltage 808 is applied to the Faraday cup 801B. Due to the effect of the bias voltage 808 used to bias the Faraday cup 801B mentioned above, the ion beam 803a that diverges and is deviated outside the Faraday cup 801A when no bias voltage is applied can now be deflected close to the opening of the Faraday cup 801B and re-received by the biased Faraday cup 801B. Of course, the ion beam 803b that passes through the reaction chamber without divergence or deviation still travels along the ion beam path and hits the bottom of the biased Faraday cup 801B as usual. The result is that as Figure 8A and Figure 8B shown, the total ion beam received by the unbiased Faraday cup 801A can be different from the total ions received by the analyzer 806. Because in Figure 8A , the ion beam 803 gradually widens after passing through the plane on which the analyzer (206 / 306 / 806) and the chuck (204 / 304) are located. Significantly, by biasing the Faraday cup as in the present invention, the ion beam received by the biased Faraday cup 801B can be almost equal to the ion beam received by the analyzer 906, because the divergence of the ion beam 803 can be suppressed after passing through the plane on which the analyzer (206 / 306 / 806) and the chuck (204 / 304) are located. This additional benefit of the present invention is that the analyzer and the biased Faraday cup can measure substantially equal amounts of ion beams. Accordingly, the ion beam measured by the biased Faraday cup can fully reflect the ion beam dose measured by the analyzer.

[0072] In summary, a method for reducing particle contamination in low-energy ion implantation is proposed. The steps include identifying an internal component of an ion implanter that accumulates a majority of particles after low-energy ion implantation exceeds a predetermined threshold. Secondly, the steps further include applying a required bias voltage to the identified internal component during the low-energy ion implantation cycle. Applying the required bias voltage to the identified component can be continuous or sustained after the low-energy ion implantation is completed. The voltage required to be applied to the identified component is relative to the energy of the ions in the ion beam, so as to attract or accelerate the ions to the identified component. Depending on the recipe of the low-energy ion implantation, the range of the required voltage can be from several hundred volts to several thousand volts.

[0073] Obviously, relative to what has been described and depicted, the construction details and these embodiments can vary widely without departing from the scope to be protected by the present invention.

Claims

1. An ion implantation system, comprising: An ion beam generator configured to generate an ion beam; A wafer chuck configured to hold a wafer; A Faraday cup configured to receive at least a portion of the ion beam; And A voltage source electrically connected to the Faraday cup, wherein the voltage source is configured to apply a bias voltage to the Faraday cup when the ion beam is conducted from the ion beam generator to the wafer; A preamplifier electrically connected to the Faraday cup, wherein the preamplifier is configured to measure a first voltage of the Faraday cup; A calibration circuit electrically connected to the voltage source and the preamplifier, wherein the calibration circuit is configured to adjust a gain of the preamplifier according to the bias voltage; And A controller electrically connected to the preamplifier, wherein the controller is configured to adjust a current of the ion beam according to the gain of the preamplifier.

2. The ion implantation system according to claim 1, characterized in that, Further comprising: One or more plates embedded in the Faraday cup, wherein the voltage source is electrically connected to the one or more plates.

3. The ion implantation system according to claim 1, characterized in that, Further comprising: A reaction chamber surrounding the wafer chuck and the Faraday cup, wherein an outer wall of the reaction chamber is electrically grounded.

4. The ion implantation system according to claim 1, wherein, Further comprising: A sensor configured to monitor the ion beam conducted by the ion beam generator.

5. The ion implantation system according to claim 1, characterized in that, The controller is configured to adjust a current of the ion beam according to the voltage measured by the Faraday cup.

6. The ion implantation system according to claim 1, wherein, The voltage source is configured to apply the intensity of the bias voltage inversely proportional to the energy of the ion beam.

7. The ion implantation system according to claim 6, wherein The voltage source is configured to apply the intensity of the bias voltage inversely proportional to a current of the ion beam.

8. The ion implantation system according to claim 1, wherein The voltage source is configured to apply a negative voltage.

9. The ion implantation system according to claim 1, characterized in that, The ion beam generator is configured to conduct a pencil ion beam.

10. The ion implantation system according to claim 9, wherein The voltage source is configured to apply the bias voltage according to a required divergence of the pencil ion beam.

11. The ion implantation system according to claim 10, wherein, The Faraday cup is configured to measure a first current of the ion beam, and the ion implantation system further comprises: A sensor configured to measure a second current of the ion beam; The controller is electrically connected to the sensor, the Faraday cup and the voltage source, wherein the controller includes a memory and one or more processors, and the memory stores one or more programs, and the one or more programs include a plurality of instructions, wherein when executed by the one or more processors, cause the system to: Determine whether the first current of the ion beam is equal to the second current of the ion beam; and According to a determination that the first current of the ion beam is not equal to the second current of the ion beam, adjust the bias voltage provided by the voltage source.

12. The ion implantation system according to claim 11, wherein, The one or more programs further include a plurality of instructions, which when executed by the one or more processors, cause the system to: Determine whether a convergence of the pencil ion beam is within a minimum threshold of convergence, wherein it is based on the first current of the ion beam and the second current of the ion beam; and According to a determination that the convergence of the pencil ion beam is not less than the minimum threshold of convergence, adjust the bias voltage provided by the voltage source.

13. The ion implantation system according to claim 1, wherein The ion beam generator is configured to provide a low energy ion beam.

14. The ion implantation system according to claim 13, wherein, The ion beam generator is configured to provide the ion beam having an energy less than 1000 electron volts.

15. The ion implantation system according to claim 14, wherein The ion beam generator is configured to provide the ion beam having an energy between 200 electron volts and 500 electron volts.

16. A method for reducing particle contamination in an ion implantation system, the ion implantation system including an ion beam generator, a wafer chuck configured to hold a wafer, a Faraday cup, a voltage source electrically connected to the Faraday cup, a preamplifier electrically connected to the Faraday cup, a calibration circuit electrically connected to the voltage source and the preamplifier, and a controller electrically connected to the preamplifier, the method including: Conducting an ion beam from the ion beam generator to the wafer; and Applying a bias voltage from the voltage source to the Faraday cup during the ion beam being conducted from the ion beam generator to the wafer; Adjusting a degree of amplification of the preamplifier according to the bias voltage; and Adjusting a current of the ion beam according to the degree of amplification of the preamplifier.

17. The method according to claim 16, wherein One or more plates are embedded in the Faraday cup and electrically connected to the voltage source, and applying the bias voltage to the Faraday cup includes applying the bias voltage to the one or more plates embedded in the Faraday cup.

18. The method according to claim 16, characterized in that The ion implantation system includes a reaction chamber surrounding the wafer chuck and the Faraday cup, and the method further includes: Applying a ground voltage to an outer wall of the reaction chamber.

19. The method according to claim 16, wherein The ion implantation system includes a sensor, and the method further includes: Using the sensor to determine the current of the ion beam.

20. The method according to claim 16, wherein The method further includes: Using the preamplifier to determine a voltage of the Faraday cup; and Adjusting a current of the ion beam according to the voltage of the Faraday cup.

21. The method according to claim 16, wherein The intensity of the bias voltage is inversely proportional to an energy of the ion beam.

22. The method according to claim 21, wherein, The intensity of the bias voltage is inversely proportional to a current of the ion beam.

23. The method according to claim 22, wherein The bias voltage is a negative voltage.

24. The method according to claim 16, wherein The ion beam is a beam-shaped ion beam.

25. The method according to claim 24, wherein The bias voltage is applied according to a required divergence of the beam-shaped ion beam.

26. The method according to claim 25, wherein The ion implantation system includes a sensor, the controller is electrically connected to the sensor, the Faraday cup and the voltage source, and the method further includes: Measuring a first current of the ion beam using the Faraday cup; Measuring a second current of the ion beam using the sensor; Using the controller to determine whether the first current of the ion beam is equal to the second current of the ion beam; And According to a determination that the first current of the ion beam is not equal to the second current of the ion beam, using the controller to adjust the bias voltage provided by the voltage source.

27. The method according to claim 26, wherein Further including: Determining whether a convergence of the beam-shaped ion beam is within a minimum threshold of convergence, here according to the first current of the ion beam and the second current of the ion beam; and According to a determination that the convergence of the beam-shaped ion beam is not less than the minimum threshold of convergence, adjusting the bias voltage provided by the voltage source.

28. The method according to claim 16, wherein The ion beam is a low-energy ion beam.

29. The method according to claim 28, wherein The ion beam has an energy less than 1000 electron volts.

30. The method according to claim 29, wherein The ion beam generator is configured to provide the ion beam having an energy between 200 electron volts and 500 electron volts.

31. A non - transitory computer - readable storage medium for storing one or more programs, the one or more programs comprising a plurality of instructions that, when executed by one or more processors of an ion implantation system, cause the ion implantation system to: Conduct an ion beam from an ion beam generator of the ion implantation system to a wafer held by a wafer chuck of the ion implantation system; Apply a bias voltage to a Faraday cup of the ion implantation system using a voltage source of the ion implantation system, where the voltage source is used to apply the bias voltage when the ion beam is conducted from the ion beam generator to the wafer; Adjust a degree of amplification of a pre - amplifier according to the bias voltage; and Adjust a current of the ion beam according to the degree of amplification of the pre - amplifier.

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