Ion source implanter capable of accurately controlling beam focusing

Abstract

The utility model provides an ion source implanter capable of accurately controlling beam focusing, which comprises an ion beam system and a target table, the ion beam system comprises a gas box, an ion source, a mass analyzer, an accelerating tube and a focusing device which are connected in sequence, and the gas box and the ion source generate ion beams. Impurity ions are screened out by the mass analyzer and then are accelerated by the accelerating tube to enter the focusing device, a plurality of focusing structures arranged at intervals are arranged in the focusing device, a plurality of electrifying columns corresponding to the focusing structures are arranged on the surface of the focusing device, and the focusing structures are electrically connected to the electrifying columns, so that the focusing structures are electrified to generate acting force on the ion beams; the target table is provided with an accommodating part which is aligned with the focusing device. According to the technical scheme of the utility model, focusing can be flexibly adjusted according to the scattering degree of the ion beam, the scattering phenomenon of the ion beam is better inhibited, and the focusing degree of the ion beam is more accurately controlled.

Description

Technical Field

[0001] The utility model relates to the technical field of ion implantation equipment, and particularly relates to an ion source implanter for precisely controlling beam focusing. Background Technique

[0002] The electrical properties of semiconductor devices depend on the impurity concentration of semiconductor doping. During the manufacturing process of semiconductor wafers, to turn pure silicon with very poor conductivity into a useful semiconductor, a small amount of impurities need to be added to change its structure and conductivity. This process is called doping. Currently, there are two doping processes: high-temperature thermal diffusion method and ion implantation method, among which ion implantation occupies the mainstream position.

[0003] An ion source implanter is a device used to implant specific types of ions into wafers. Its basic working principle is to accelerate and focus a beam of ions and inject them into the target material. During the process of ion implantation, since the ion beam is composed of positive ions, it will be scattered due to the repulsive force during transmission. Therefore, a focusing device is needed to focus the ion beam.

[0004] The existing focusing device usually generates an electric field through a whole circular focusing ring to focus the ion beam. However, the scattered ions carry inconsistent kinetic energies, and the scattering speeds and paths are chaotic. After being energized, the entire focusing ring is at the same electric potential. Therefore, the focusing effect on ions is relatively limited, and it can only roughly control the focusing and cannot achieve a better focusing effect. Content of the Utility Model

[0005] In order to solve the problems in the above background technique, the utility model provides an ion source implanter for precisely controlling beam focusing, aiming to be able to flexibly adjust the focusing according to the scattering degree of the ion beam, better suppressing the scattering phenomenon of the ion beam and more precisely controlling the focusing degree of the ion beam.

[0006] The solution adopted by the utility model to solve its technical problems is: an ion source implanter for precisely controlling beam focusing, including:

[0007] An ion beam system, the ion beam system includes a gas box, an ion source, a mass analyzer, an acceleration tube and a focusing device connected in sequence. The gas box and the ion source generate an ion beam, which is screened by the mass analyzer to select impurity ions and then accelerated by the acceleration tube and injected into the focusing device. A number of focusing structures are arranged at intervals in the focusing device, and a number of energized columns are provided on the surface of the focusing device corresponding to the focusing structures. The focusing structures are electrically connected to the energized columns so that the focusing structures are energized to generate a force on the ion beam;

[0008] A target platform is provided with a receiving portion thereon, and the receiving portion is aligned with the focusing device.

[0009] In an embodiment of the present invention, the focusing device has an ion channel inside, the side wall of the focusing device is hollow to form an electrode cavity, and a plurality of focusing structures are arranged at intervals along the ion channel in the electrode cavity.

[0010] In an embodiment of the present invention, the focusing structure includes at least two electrodes symmetrically arranged with respect to the ion channel.

[0011] In an embodiment of the present invention, the electrodes of every two adjacent focusing structures are arranged in a staggered manner.

[0012] In an embodiment of the present invention, the inner diameter of the ion channel gradually decreases along the moving direction of the ion beam.

[0013] In an embodiment of the present invention, the side wall of the ion channel is coated with a graphite protective layer.

[0014] In summary, the beneficial effects of the present invention are as follows: The technical solution of the present invention sets a focusing device at the outlet of the acceleration tube, and a plurality of focusing structures arranged at intervals are provided in the focusing device. The focusing structure is composed of at least two opposite electrodes. After applying a voltage to the electrodes, a force can be generated on the ion beam to suppress the scattered ions. By adjusting the voltage magnitudes on different electrodes according to the scattering situation of the ion beam, the best effect of suppressing ion scattering can be achieved, and the focal length of the ion beam can also be adjusted. The technical solution of the present invention can flexibly adjust the focus according to the scattering degree of the ion beam, better suppress the scattering phenomenon of the ion beam, and control the focusing degree of the ion beam more precisely.

[0015] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the following specific preferred embodiments are given and described in detail in conjunction with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of this embodiment;

[0017] Figure 2 is a cross-sectional view of the focusing device of this embodiment;

[0018] Figure 3 is a schematic diagram of the arrangement of the focusing structures of this embodiment.

[0019] In the figure: 1. Ion beam system; 2. Gas box; 3. Ion source; 4. Mass analyzer; 5. Accelerating tube; 6. Focusing device; 61. Focusing structure; 62. Energizing column; 63. Ion channel; 64. Electrode chamber; 65. Electrode; 66. Graphite protective layer; 7. Target stage; 71. Accommodating portion. Detailed implementation mode

[0020] In order to make the content of the present utility model easier to be clearly understood, the following further illustrates the present utility model according to specific embodiments and in conjunction with the accompanying drawings.

[0021] It should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc. used in this article is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present utility model. Unless otherwise specified, the meaning of "plurality" is two or more.

[0022] Unless otherwise clearly defined and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood through specific situations.

[0023] As Figures 1 to 3 shown, the present utility model provides an ion source 3 injector for precisely controlling beam focusing, including an ion beam system 1 and a target stage 7. The ion beam system 1 includes a gas box 2, an ion source 3, a mass analyzer 4, an accelerating tube 5, and a focusing device 6 connected in sequence. The gas box 2 and the ion source 3 generate an ion beam, and after the impurity ions are screened out by the mass analyzer 4, they are accelerated by the accelerating tube 5 and injected into the focusing device 6. A plurality of focusing structures 61 arranged at intervals are provided inside the focusing device 6, and a plurality of energizing columns 62 are provided on the surface of the focusing device 6 corresponding to the focusing structures 61. The focusing structures 61 are electrically connected to the energizing columns 62 so that the focusing structures 61 are energized to generate a force on the ion beam; an accommodating portion 71 is provided on the target stage 7, and the accommodating portion 71 is aligned with the focusing device 6.

[0024] Understandably, the structures of the gas box 2, ion source 3, mass analyzer 4, and acceleration tube 5 are all prior arts and will only be briefly introduced here. The gas box 2 is used to provide the gas to be ionized for the ion source 3. The thermoelectrons generated in the ion source 3 bombard gas molecules under the action of an electric field to ionize them. All positively charged ions are repelled by the positive pressure of the anode of the ion source 3 and are drawn out from a slit. At this time, the electrons in the plasma are repelled by the cathode and are blocked, thus forming an ion beam composed of positive ions. When the thermoelectrons bombard the impurity source gas molecules, multiple types of ions will be generated, and the mass-to-charge ratio of each type of ion is different. When passing through the mass analyzer 4, under the action of magnetic force, the movement trajectories of the ions will be different, and the required impurity ions can be separated from the mixed ion beam. In order to enable the ions to obtain greater energy to meet the implantation requirements, the positive ions also need to obtain the required speed through the high voltage of the acceleration tube 5 after coming out of the mass analyzer 4. The acceleration tube 5 is composed of a series of electrodes isolated by a medium, and the negative voltages on the electrodes increase sequentially. When the positive ions enter the acceleration tube 5, each negative electrode accelerates the ions step by step. The higher the total voltage, the faster the movement speed of the ions, that is, the greater the kinetic energy.

[0025] After the ion beam leaves the accelerator, it enters the focusing device 6. The focusing device 6 has a channel for the ions to flow. Inside the focusing device 6, a plurality of focusing structures 61 are arranged along this channel. After applying a voltage to the focusing structures 61, a force will be generated on the ion beam moving along the channel to achieve the focusing effect. The directions of the forces generated by the plurality of focusing structures 61 on the ion beam are not the same. According to the scattering situation of the ion beam, the voltage magnitudes on different focusing structures 61 can be adjusted to achieve the best effect of suppressing ion scattering, and the focal length of the ion beam can also be adjusted. Compared with the traditional method of using an entire focusing ring for focusing, this method has the advantages of flexible adjustment method and good focusing effect.

[0026] The target stage 7 is used to place the wafer to be doped. The target stage 7 can also be externally connected to a servo motor to facilitate lifting, rotation, and other movements. A receiving portion 71 is provided on the target stage 7. The size of the receiving portion 71 matches the size of the wafer, and the wafer is placed inside the receiving portion 71, and the receiving portion 71 is aligned with the outlet of the focusing device 6 to facilitate the ion beam emitted from the focusing device 6 to be implanted into the wafer.

[0027] As Figure 2 shown, in an embodiment of the present application, the inside of the focusing device 6 has an ion channel 63, and the side wall of the focusing device 6 is internally hollow to form an electrode cavity 64. A plurality of focusing structures 61 are arranged at intervals along the ion channel 63 inside the electrode cavity 64.

[0028] Understandably, one end of the ion channel 63 is connected to the outlet of the acceleration tube 5. The ion beam enters the focusing device 6 from within the acceleration tube 5 and moves along the ion channel 63. The side wall of the ion channel 63 is a hollow structure, forming a cavity called the electrode cavity 64. A plurality of focusing structures 61 are arranged in the cavity along the moving direction of the ion beam. When the ion beam moves within the ion channel 63, applying a voltage to the focusing structures 61 can suppress the scattered ions. At the same time, according to the scattering situation of the ions, the voltage magnitudes on different focusing structures 61 can be adjusted to achieve the best focusing effect, and the focal length of the ion beam can also be adjusted.

[0029] As Figures 2 to 3 shown, in an embodiment of the present application, the focusing structure 61 includes at least two electrodes 65 that are symmetrically arranged with respect to the ion channel 63.

[0030] Understandably, the electrodes 65 are symmetrically arranged with respect to the ion channel 63, and the two electrodes 65 are connected in series. After applying a voltage to the electrodes 65 through the energizing column 62, the two electrodes 65 apply forces to the ion beam from opposite directions to suppress the scattering of ions and control the focusing of the ion beam. Compared with the traditional method of using an entire focusing ring to control focusing, using two symmetrically arranged electrodes 65 can more accurately suppress the ion scattering in a fixed direction. By arranging multiple electrodes 65 in different focusing structures 61, the focal length of the ion beam can be flexibly adjusted, and the suppression effect on scattered ions is also better.

[0031] As Figures 2 to 3 shown, in an embodiment of the present application, the electrodes 65 of every two adjacent focusing structures 61 are arranged in a staggered manner.

[0032] Understandably, arranging the electrodes 65 in a staggered manner is to suppress the ions scattered in different directions in the ion beam. According to the scattering situation of the ion beam, the voltage magnitudes of the electrodes 65 on different focusing structures 61 can be adjusted to achieve the best effect of suppressing ion scattering, and the focal length of the ion beam can also be adjusted. Compared with the traditional method of using an entire focusing ring for focusing, this method has the advantages of flexible adjustment method and good focusing effect.

[0033] As Figure 2 shown, in an embodiment of the present application, the inner diameter of the ion channel 63 gradually decreases along the moving direction of the ion beam.

[0034] Understandably, the ion channel 63 is a conical structure with a uniformly shrinking inner diameter. The end with a larger inner diameter is the end where the ion beam enters, and the end with a smaller inner diameter is the end where the ion beam exits. The closer the focusing structure 61 is to the exit end, the closer it is to the ion beam in the ion channel 63, and the stronger the force on the ion beam. Through the above settings, it is convenient to control the focusing of the ion beam, making it more concentrated closer to the exit of the ion channel 63.

[0035] As Figure 2 shown, in an embodiment of the present application, the side wall of the ion channel 63 is coated with a graphite protective layer 66.

[0036] Understandably, since a very small number of ions may carry large kinetic energies and impact the inner wall of the ion channel 63, over time, it will cause metal contamination and may even penetrate the inner wall, damaging the electrode 65. The setting of the graphite protective plate can protect the inner wall of the ion channel 63 and prevent metal contamination.

[0037] In summary, the beneficial effects of this embodiment are as follows: In this embodiment, a focusing device 6 is provided at the exit of the acceleration tube 5. A number of focusing structures 61 arranged at intervals are provided in the focusing device 6. The focusing structure 61 is composed of at least two opposite electrodes 65. After applying a voltage to the electrodes 65, a force can be generated on the ion beam to suppress scattered ions. By adjusting the voltage magnitudes on different electrodes 65 according to the scattering situation of the ion beam, the best effect of suppressing ion scattering can be achieved, and the focal length of the ion beam can also be adjusted. The technical solution of the present utility model can flexibly adjust the focusing according to the scattering degree of the ion beam, better suppress the scattering phenomenon of the ion beam, and control the focusing degree of the ion beam more precisely.

[0038] The above-described embodiments are only the preferred embodiments of the present utility model and cannot be used to limit the protection scope of the present utility model. Any non-substantive changes and modifications made by those skilled in the art based on the present utility model fall within the protection scope of the present utility model.

Claims

1. An ion source injector for precisely controlling beam focusing, characterized in that, Comprising an ion beam system (1), the ion beam system (1) includes a gas box (2), an ion source (3), a mass analyzer (4), an acceleration tube (5), and a focusing device (6) connected in sequence. The gas box (2) and the ion source (3) generate an ion beam, which is screened for impurity ions by the mass analyzer (4) and then accelerated by the acceleration tube (5) and injected into the focusing device (6). The focusing device (6) is provided with a number of focusing structures (61) arranged at intervals. Corresponding to the focusing structures (61), a number of energizing columns (62) are provided on the surface of the focusing device (6). The focusing structures (61) are electrically connected to the energizing columns (62) so that the focusing structures (61) are energized to generate a force on the ion beam; A target stage (7), on which a receiving portion (71) is provided, and the receiving portion (71) is aligned with the focusing device (6).

2. The ion source implanter for precisely controlling beam focusing according to claim 1, wherein The interior of the focusing device (6) has an ion channel (63). The side wall of the focusing device (6) is internally hollow to form an electrode cavity (64), and a number of focusing structures (61) are arranged at intervals along the ion channel (63) in the electrode cavity (64).

3. The ion source implanter for precisely controlling beam focusing according to claim 2, wherein The focusing structure (61) includes at least two electrodes (65) symmetrically arranged with respect to the ion channel (63).

4. The ion source implanter for precisely controlling beam focusing according to claim 3, wherein The electrodes (65) of every two adjacent focusing structures (61) are arranged in a staggered manner.

5. The ion source implanter for precisely controlling beam focusing according to claim 4, wherein The inner diameter of the ion channel (63) gradually decreases along the moving direction of the ion beam.

6. The ion source implanter for precisely controlling beam focusing according to claim 5, wherein The side wall of the ion channel (63) is coated with a graphite protective layer (66).

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