Faraday cup device

Abstract

This invention provides a Faraday cup device, including a cup body assembly, a conductor, a rotating mechanism, and a detection unit. The cup body assembly includes a cup body. The conductor is disposed within the cup body and is used to receive impacts from an ion beam entering from the cup opening. The rotating mechanism is connected to the conductor and is used to drive the conductor to rotate. The detection unit is connected to the conductor and is used to measure the current in the conductor. During the rotation of the conductor, the losses caused by the ion beam impacts are evenly distributed on the surface of the conductor, thereby improving the service life of the Faraday cup device.

Description

Technical Field

[0001] This invention relates to the field of charged particle beam detection technology, and more particularly to a Faraday cup device. Background Technology

[0002] Ion implantation is a process in which atoms or molecules are ionized into cations, accelerated to a certain energy by an electric field, and non-target ions are removed by a magnetic field. These cations are then implanted into specific regions of a silicon wafer, and after annealing and activation, the impurity ions are able to produce the desired electrical properties. Currently, ion implantation is crucial in large-scale and very large-scale integrated circuit manufacturing. A complete process may require hundreds of ion implantation steps. Because it allows for precise control of parameters such as cation acceleration energy, implantation location, and implantation angle, it has perfectly replaced traditional thermal doping processes. The implantation depth and dosage of impurity ions are controllable, lateral impurity diffusion is minimal, and uniformity and purity are excellent. Semiconductor products prepared using ion implantation have advantages such as high stability, high yield, and long lifespan. Therefore, the widespread use and crucial role of this process make ion implanters one of the key pieces of equipment in integrated circuit manufacturing and related industries.

[0003] The Faraday cup is a crucial component of an ion implanter, widely used for functions such as measuring ion beam current, assisting in monitoring beam parallelism, and blocking the beam when stability fluctuates. Although the Faraday cup does not directly participate in beam formation, ion acceleration / deceleration, or screening, its timely monitoring and feedback control of the beam in an ion implanter is significant for improving ion beam quality, monitoring beam size and stability, achieving targeted implantation dose control, ensuring uniformity and stability of the ion implantation process, and ultimately improving product yield and device performance.

[0004] In existing technologies, Faraday cups are prone to burn-through and damage due to prolonged impact from ion beams, affecting normal process control and hindering equipment productivity. This is especially true in ion implanters with high beam currents, where the Faraday cup has a short lifespan and requires frequent replacement.

[0005] Therefore, it is necessary to develop a new Faraday cup device that can improve some of the problems existing in the prior art. Summary of the Invention

[0006] The purpose of this invention is to provide a Faraday cup device that can improve its service life.

[0007] To achieve the above objectives, the Faraday cup device provided by the present invention includes a cup body assembly, a conductor, a rotating mechanism, and a detection unit; the cup body assembly includes a cup body; the conductor is disposed within the cup body and is used to receive impacts from an ion beam entering from the cup opening; the rotating mechanism is connected to the conductor and is used to drive the conductor to rotate; the detection unit is connected to the conductor and is used to measure the current in the conductor.

[0008] The beneficial effects of the Faraday cup device provided by the present invention are as follows: During use, the ion beam enters from the cup opening and strikes the conductor. The rotating mechanism is connected to the conductor and the conductor is rotated. During the rotation of the conductor, the loss caused by the ion beam impact is evenly distributed on the surface of the conductor, thereby improving the service life of the Faraday cup device.

[0009] Optionally, the conductor is a solid structure and the conductor is cylindrical in shape.

[0010] Optionally, the conductor has a nested structure, comprising a first conductive portion and a second conductive portion, with the second conductive portion disposed within the first conductive portion. The first and second conductive portions are insulated from each other, and the detection unit is connected to both the first and second conductive portions. The advantage is that when the first conductive portion is damaged by ion beam impact, the ion beam impacts the second conductive portion, generating a current. Because the first and second conductive portions are insulated from each other, the detection unit can detect the current on the second conductive portion and thus determine that the Faraday cup device is damaged, facilitating timely reminders to relevant personnel for maintenance.

[0011] Optionally, the rotating mechanism drives the conductor to rotate in a step-by-step manner. The advantages are that, compared to uniform rotation, step-by-step rotation results in a faster rotation speed when rotating at the same angle, and a shorter time for friction to occur between components due to relative motion, thus reducing the number of particles generated by friction.

[0012] Optionally, the cup assembly includes a conductive bearing, which supports the rotation of the conductor and electrically connects the conductor and the cup. The advantages are: the bearing supports rotation, further reducing friction and particle size; the conductive bearing allows current to pass through, enabling the electrical connection between the conductor and the cup, thus allowing simultaneous detection of ions impacting both the conductor and the cup.

[0013] Optionally, the cup assembly includes a magnetic field generator disposed on the outer wall of the cup body. The magnetic field generator is used to generate a magnetic field inside the cup body near the rim. The beneficial effect is that by generating a magnetic field inside the cup body near the rim, the magnetic field can prevent external electrons from entering the cup body and prevent internal electrons generated by collisions inside the cup body from escaping, thereby improving the measurement accuracy of the ion beam.

[0014] Optionally, the magnetic field generator includes a first magnetic field generating section and a second magnetic field generating section, respectively used to generate a first magnetic field and a second magnetic field inside the cup body. The first magnetic field generating section and the second magnetic field generating section are arranged sequentially along the direction of the ion beam, so that the ion beam passes through the first magnetic field and the second magnetic field sequentially. Its beneficial effect is that the second magnetic field applies a Lorentz force to the ion beam, causing the ions in the ion beam to be deflected and impact the inner wall of the cup body, thereby reducing the impact of ions on the conductor and distributing the material loss caused by ion impacts to the conductor and the cup wall, thus improving the service life of the Faraday cup device.

[0015] Optionally, the second magnetic field is stronger than the first magnetic field.

[0016] Optionally, the second magnetic field generating unit includes a polarity reversal module, which is used to interchange the polarities of the two poles of the second magnetic field. The beneficial effect is that by reversing the polarities of the two poles of the second magnetic field through the polarity reversal module, the second magnetic field can apply a Lorentz force in opposite directions to the ions in the ion beam, thereby dispersing some of the ions in the ion beam and impacting them onto the two opposing inner wall surfaces of the cup body. This results in a more uniform distribution of material loss between the conductor and the two opposing inner wall surfaces of the cup body, further improving the service life of the Faraday cup device. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the Faraday cup in an embodiment of the present invention;

[0018] Figure 2 for Figure 1 The diagram shows a cross-sectional structure of the Faraday cup.

[0019] Figure 3 This is a schematic diagram of the direction of ion movement during the first time period in an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the direction of ion movement during the second time period in an embodiment of the present invention.

[0021] Figure label:

[0022] 1. Cup body; 101. First inner surface; 102. Second inner surface; 2. Conductor; 201. First conductive part; 202. Second conductive part; 301. First detection part; 302. Second detection part; 4. Drive wheel; 5. Ion beam; 501. Internal electron; 502. External electron; 503. Ion; 5031. Weak ion; 5032. Strong ion; 6. Conductive bearing; 7. Magnetic field generator; 701. First magnetic field generating part; 702. Second magnetic field generating part. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, but does not exclude other elements or objects.

[0024] Figure 1 This is a schematic diagram of the Faraday cup in an embodiment of the present invention; Figure 2 for Figure 1 The diagram shows a cross-sectional structure of the Faraday cup.

[0025] To address the problems existing in the prior art, embodiments of the present invention provide a Faraday cup device, referring to... Figure 1 and Figure 2 The Faraday cup device includes a cup body assembly, a conductor 2, a rotating mechanism, and a detection unit. The cup body assembly includes a cup body 1, and the conductor 2 is disposed inside the cup body 1. The conductor 2 is used to receive the impact of the ion beam 5 entering from the cup opening. The rotating mechanism is connected to the conductor 2 and is used to drive the conductor 2 to rotate. The detection unit is connected to the conductor 2 and is used to measure the current of the conductor 2.

[0026] Specifically, refer to Figure 2 The conductor 2 is grounded, and the detection unit is connected to the conductor 2. When the ion beam 5 enters the cup body 1 from the cup opening and strikes the conductor 2, the detection unit detects the current flowing through the conductor 2 and detects the ion beam 5 by judging the current.

[0027] In some specific embodiments of the present invention, the conductor is a solid cylinder, the material of the conductor is graphite, and the rotating mechanism drives the conductor to rotate around the axis of the cylinder, so that the material loss on the conductor is evenly distributed on the cylindrical surface of the cylinder.

[0028] In some specific embodiments of the present invention, reference is made to Figure 1 and Figure 2 The rotating mechanism includes a drive wheel 4 and a motor (not shown in the figure). The drive wheel 4 is connected to one end of the conductor 2 and is insulated from the conductor 2. The motor drives the drive wheel 4 and thus drives the conductor 2 to rotate.

[0029] In some specific embodiments of the present invention, the motor is driven by a frequency converter or a driver to make the conductor 2 rotate in a step-like manner, that is, the conductor 2 remains stationary during the time interval between two consecutive rotations, and the angle of each rotation of the conductor 2 is constant.

[0030] In some other specific embodiments of the present invention, the rotating mechanism includes a drive wheel, an intermittent motion mechanism connected to the drive wheel, and a motor. The motor rotates, and the intermittent motion mechanism drives the drive wheel, which in turn drives the conductor to rotate in a stepwise manner. The intermittent motion mechanism can be a Geneva mechanism.

[0031] In some specific embodiments of the present invention, reference is made to Figure 1 The cup body 1 includes four cup walls, and two opposite cup walls are provided with through holes. The two ends of the conductor 2 are rotatably disposed in the through holes.

[0032] In some specific embodiments of the present invention, reference is made to Figure 2 The cup assembly includes a conductive bearing 6, which is disposed in the through hole and supports the rotation of the conductor 2, and electrically connects the conductor 2 and the cup 1.

[0033] In some specific embodiments of the present invention, reference is made to Figure 2 The conductive bearing 6 has a graphite coating on its surface, which enables the conductor 2 to be electrically connected to the cup body 1.

[0034] In some specific embodiments of the present invention, the detection unit can be various current measuring tools, such as an ammeter.

[0035] In some embodiments of the present invention, reference is made to Figure 1 and Figure 2The conductor 2 has a nested structure, including a first conductive part 201 and a second conductive part 202. The second conductive part 202 is disposed inside the first conductive part 201, and the first conductive part 201 and the second conductive part 202 are insulated from each other. The detection unit includes a first detection part 301 and a second detection part 302, which are respectively connected to the first conductive part 201 and the second conductive part 202. Since the first conductive part 201 is hollow, when the material between the inner and outer surfaces of the first conductive part 201 is broken down by the ion beam 5, the ion beam 5 strikes the second conductive part 202, causing the detection unit to detect the current generated on the second conductive part 202. This helps relevant engineers to know in a timely manner that the Faraday cup device needs maintenance.

[0036] In some specific embodiments of the present invention, reference is made to Figure 1 and Figure 2 The first conductive part 201 is a graphite column, and the graphite column has a through hole along its axis. The second conductive part 202 can be a slender conductive material, such as a copper wire or a graphite strip. A gap is left between the second conductive part 202 and the first conductive part 201 so that the first conductive part 201 and the second conductive part 202 are insulated from each other.

[0037] In some embodiments of the present invention, reference is made to Figure 2 The first conductive part 201 is rotatably disposed on the cup body 1 via the conductive bearing 6, and the second conductive part 202 is supported by an insulated ceramic bearing. The movement of the second conductive part 202 and the first conductive part 201 is independent of each other, that is, the second conductive part 202 does not rotate with the rotation of the first conductive part 201.

[0038] In some embodiments of the present invention, reference is made to Figure 1 and Figure 2 The cup assembly includes a magnetic field generator 7 disposed on the outer wall of the cup body 1. The magnetic field generator 7 is used to generate a magnetic field inside the cup body 1 near the mouth of the cup. The magnetic field prevents external electrons 502 from entering the cup body 1 and prevents internal electrons generated by impacts inside the cup body 1 from escaping the interior of the cup body 1.

[0039] Specifically, the magnetic field generator 7 can be a permanent magnet or an energized coil.

[0040] In some embodiments of the present invention, reference is made to Figure 1 and Figure 2The magnetic field generator 7 includes a first magnetic field generating part 701 and a second magnetic field generating part 702, which are used to generate a first magnetic field and a second magnetic field inside the cup body 1, respectively. The first magnetic field generating part 701 and the second magnetic field generating part 702 are arranged sequentially along the direction of the ion beam 5, that is, along the direction A shown in the figure, so that the ion beam 5 passes through the first magnetic field and the second magnetic field in sequence.

[0041] In some embodiments of the present invention, the second magnetic field generating unit includes an energized coil, and the second magnetic field is made stronger than the first magnetic field by increasing the current on the energized coil.

[0042] Figure 3 This is a schematic diagram of the direction of ion movement during the first time period in an embodiment of the present invention; Figure 4 This is a schematic diagram of the direction of ion movement during the second time period in an embodiment of the present invention.

[0043] In some embodiments of the present invention, reference is made to Figure 1 , Figure 3 and Figure 4 The second magnetic field generating unit 702 includes an energized coil and a polarity reversal module. The polarity reversal module changes the direction of the current on the energized coil, causing the polarities of the two poles of the second magnetic field to be reversed. During the first time period and the second time period, Lorentz forces in different directions are applied to the ions 503 in the ion beam 5, so that during the first time period, some of the ions 503 in the ion beam 5 impact the first inner surface 101 of the inner side of the cup wall, and during the second time period, some of the ions 503 in the ion beam 5 impact the second inner surface 102 of the inner side of the cup wall. By controlling the duration of the first time period and the second time period, the material loss of the cup body 1 is evenly distributed on the first inner surface 101 and the second inner surface 102.

[0044] In some embodiments of the present invention, by combining the start-up and shutdown of the second magnetic field generator and the reversal of the polarity of the two poles, the ions in the ion beam 5 are respectively bombarded on the surface of the first conductive part 201, the first inner surface 101 and the second inner surface 102, so that the material loss is evenly distributed on the surface of the first conductive part 201, the first inner surface 101 and the second inner surface 102.

[0045] Specifically, refer to Figure 1 , Figure 3 and Figure 4The different ions 503 in the ion beam 5 have different energies. The strong ions 5032 with higher energy are deflected by the Lorentz force with a larger deflection radius and impact the area on the first inner surface 101 or the second inner surface 102 away from the cup opening. The weak ions 5031 with lower energy are deflected by the Lorentz force with a smaller deflection radius and impact the area on the first inner surface 101 or the second inner surface 102 near the cup opening. This improves the uniformity of material loss on the first inner surface 101 or the second inner surface 102.

[0046] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A Faraday cup device, characterized in that, include: A cup assembly, the cup assembly including a cup body; a conductor disposed within the cup body, the conductor being used to receive impacts from an ion beam entering from the cup opening; A rotating mechanism connected to the conductor, the rotating mechanism being used to drive the conductor to rotate; a detection unit connected to the conductor, the detection unit being used to measure the current of the conductor; The cup assembly includes a magnetic field generator disposed on the outer wall of the cup body, the magnetic field generator being used to generate a magnetic field inside the cup body near the rim.

2. The Faraday cup device according to claim 1, characterized in that, The conductor is a solid structure and is cylindrical in shape.

3. The Faraday cup device according to claim 2, characterized in that, The conductor has a nested structure, and includes a first conductive part and a second conductive part. The second conductive part is disposed inside the first conductive part, and the first conductive part and the second conductive part are insulated from each other. The detection unit is connected to the first conductive part and the second conductive part respectively.

4. The Faraday cup apparatus according to claim 1, characterized in that, The rotating mechanism drives the conductor to rotate in a stepwise manner.

5. The Faraday cup device according to claim 1, characterized in that, The cup assembly includes a conductive bearing, which supports the rotation of the conductor and provides an electrical connection between the conductor and the cup.

6. The Faraday cup apparatus according to claim 1, characterized in that, The magnetic field generator includes a first magnetic field generating part and a second magnetic field generating part, which are used to generate a first magnetic field and a second magnetic field inside the cup body, respectively. The first magnetic field generating part and the second magnetic field generating part are arranged sequentially along the direction of the ion beam, so that the ion beam passes through the first magnetic field and the second magnetic field in sequence.

7. The Faraday cup device according to claim 6, characterized in that, The second magnetic field is stronger than the first magnetic field.

8. The Faraday cup device according to claim 7, characterized in that, The second magnetic field generating unit includes a polarity reversal module, which is used to interchange the polarities of the two poles of the second magnetic field.

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