Microwave plasma gun and ion implanter
By setting coaxial electron escape holes on the sidewall of the plasma chamber and limiting their cross-sectional area, the problem of gas leakage in the plasma chamber was solved, and the working performance and ion implantation accuracy of the microwave plasma gun were improved.
Patent Information
- Application Number
- CN202522458537.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-20
- Publication Date
- 2026-01-13
- Estimated Expiration
- 2035-11-20
AI Technical Summary
During ion implantation, gas leakage within the plasma chamber can degrade the performance of the microwave plasma gun, affecting ion implantation accuracy and device quality.
By setting electron escape holes on the side wall of the plasma chamber, making them coaxial with the electron cyclotron resonance region, and designing the total cross-sectional area of the electron escape holes to be smaller than the cross-sectional area of the cyclotron resonance region, it is ensured that the gas leakage path is ionized through the resonance region, thereby reducing gas leakage.
It effectively reduces gas leakage in the plasma chamber, improves the working performance of the microwave plasma gun, extends the service life of the vacuum pump, reduces inert gas consumption and microwave costs, and ensures the stability and injection accuracy of the ion beam.
Smart Images
Figure CN223797332U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of semiconductor process equipment, and more particularly to a microwave plasma gun and an ion implanter. Background Technology
[0002] During ion implantation, positively charged ions, once implanted into a silicon wafer, accumulate charge on the wafer surface, generating electrostatic high voltage. In severe cases, this can damage devices already fabricated on the wafer. To address this issue, ion implanters utilize microwave plasma guns. These guns contain a plasma chamber into which inert gas (such as xenon) and microwaves are introduced. This ionizes the gas atoms or molecules, generating plasma and creating an electron cyclotron resonance (ECR) region within the plasma chamber. The plasma chamber has an opening facing the ion beam. When the potential of a positively charged ion beam passing near the plasma chamber exceeds the chamber's potential, electrons from the ECR region are attracted by the electric field and ejected from the opening.
[0003] However, because the formation location of the electron cyclotron resonance region within the plasma chamber occupies a portion of the plasma chamber, gas in areas where the electron cyclotron resonance region has not formed leaks to the outside (e.g., the ion beam channel) through the opening, affecting the working performance of the microwave plasma gun and thus reducing ion implantation accuracy and device quality.
[0004] Therefore, how to reduce the leakage of gas in the plasma chamber and improve the working performance of the microwave plasma gun has become a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content
[0005] This invention provides a microwave plasma gun and an ion implanter to reduce gas leakage within the plasma chamber and improve the performance of the microwave plasma gun.
[0006] To achieve the above objectives, the present invention provides the following technical solutions:
[0007] In a first aspect, this utility model embodiment provides a microwave plasma gun, including: a plasma chamber;
[0008] The plasma chamber is used to contain microwaves and gas, and an electron cyclotron resonance region is formed within the plasma chamber;
[0009] At least one electron escape hole is provided on the side wall of the plasma chamber; along the axial direction of the electron escape hole, the position of the electron escape hole corresponds coaxially with the position of the electron cyclotron resonance region, and in the direction perpendicular to the axial direction, the total cross-sectional area of the electron escape hole is smaller than the cross-sectional area of the electron cyclotron resonance region.
[0010] Secondly, this utility model embodiment provides an ion implanter that uses the microwave plasma gun described in the first aspect.
[0011] The microwave plasma gun provided in this embodiment adjusts the position of the electron vent hole so that, along the axial direction of the electron vent hole, its position corresponds coaxially with the location of the electron cyclotron resonance region. This allows potential gas leakage paths to approach the electron cyclotron resonance region. If gas attempts to escape from the electron vent hole, it will inevitably pass through the electron cyclotron resonance region, which means there is a high probability of ionization into plasma. The ionized plasma is positively charged and repels the external ion beam channel, thus preventing gas from escaping at the electron vent hole and reducing gas leakage. Furthermore, in this invention, in the direction perpendicular to the axial direction, the total cross-sectional area of the electron vent hole is smaller than the cross-sectional area of the electron cyclotron resonance region. This ensures that the electron vent hole and its surrounding area are completely within the region of the electron cyclotron resonance region, further enhancing the effect of the coaxial correspondence between the position of the electron vent hole and the location of the electron cyclotron resonance region along the axial direction, thus reducing the risk of gas leakage. Meanwhile, because the electron escape aperture precisely corresponds to the electron cyclotron resonance region, electrons generated in the electron cyclotron resonance region do not need to migrate long distances and can be efficiently extracted directly through the electron escape aperture, thus improving the effective electron utilization rate. This avoids the situation in related technologies where electrons are easily damaged by hitting the cavity wall during long-distance diffusion within the plasma chamber. Therefore, the technical solution provided by this embodiment can reduce the degree of gas leakage within the plasma chamber and improve the working performance of the microwave plasma gun. Attached Figure Description
[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0013] Figure 1 This is a schematic diagram of the structure of a microwave plasma gun in related technologies;
[0014] Figure 2This is a schematic diagram showing the distribution of the electron cyclotron resonance region in the plasma chamber of a microwave plasma gun in related technologies;
[0015] Figure 3 This is a schematic diagram of the structure of a microwave plasma gun provided in an embodiment of the present invention;
[0016] Figure 4 This is another structural schematic diagram of the microwave plasma gun provided in this embodiment of the utility model;
[0017] Figure 5 This is another structural schematic diagram of the microwave plasma gun provided in this embodiment of the present invention.
[0018] Figure label:
[0019] A schematic diagram of the structure of a microwave plasma gun in related technologies ( Figure 1 ):
[0020] 11. Plasma chamber; 12. Conductive rod; 13. Water-cooled channel; 14. Dielectric tube; 15. Opening; 16. Microwave input terminal; 17. Gas input terminal;
[0021] A schematic diagram of the structure of the microwave plasma gun provided in this embodiment of the utility model ( Figures 3-5 ):
[0022] 21. Plasma chamber; 22. Microwave input terminal; 23. Gas input terminal; 24. Electron escape aperture; 25. Ion beam; 26. Baffle. Detailed Implementation
[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0024] Plasma implantation is a crucial doping process in the chip industry, directly determining the electrical performance of core chip components (such as transistors) and serving as a vital bridge between chip design and manufacturing. The chip industry process can be broadly divided into three core stages:
[0025] Chip design stage: Circuit logic design and layout design are completed using EDA (Electronic Design Automation) tools, and layout files (GDSII format, Graphic Database System II) are output for manufacturing.
[0026] Chip manufacturing stage: Based on the design layout, a series of physical / chemical processes such as photolithography, etching, thin film deposition, and ion implantation are used on the silicon wafer to transform the design pattern into actual semiconductor devices and circuits. Plasma implantation is the core step of the "doping process" in the manufacturing stage, used to precisely control the electrical characteristics (N-type / P-type doping) of specific areas of the silicon wafer.
[0027] Chip verification phase: This includes design verification (verifying the correctness of the design through simulation before tape-out) and post-manufacturing testing verification (checking whether the chip's functions and performance meet the standards), with an emphasis on confirming the functions and performance.
[0028] In the chip manufacturing stage, in order to achieve precise doping of semiconductor materials, it is usually necessary to perform ion implantation on the chip. Ion implantation introduces specific impurity ions in a controlled manner to change the electrical properties (such as conductivity) of local areas in the chip, thereby constructing basic electronic components such as transistors, diodes, and resistors, and ultimately forming the circuit function of the chip.
[0029] During ion implantation, charged ions are implanted into a silicon wafer, where they accumulate charge on the wafer surface, generating electrostatic high voltage. In severe cases, this can damage devices already fabricated on the wafer. To address this issue, ion implanters use plasma guns (e.g., microwave plasma guns) positioned in front of the silicon wafer along the path of the ion beam (ion beam channel). This allows electrons ejected from the plasma gun to reach the silicon wafer surface under the attraction of the space charge in the ion beam, neutralizing the positive charge accumulated on the wafer surface.
[0030] A microwave plasma gun is essentially a device that uses microwave energy to excite plasma. Its core function is to generate high-density, low-energy charged particles (mainly electrons, supplemented by a small number of ions). By directionally delivering these particles to the silicon wafer surface, the positive charge remaining after ion implantation is counteracted, thus avoiding device damage or process failure caused by charge accumulation.
[0031] Specifically, Figure 1 This is a schematic diagram of the structure of a microwave plasma gun in related technologies. Please refer to it. Figure 1The microwave plasma gun contains a plasma chamber 11. An inert gas (such as xenon) is introduced into the plasma chamber 11 through the gas input terminal 17, and microwaves are introduced into the plasma chamber 11 through the microwave input terminal 16, ionizing the gas atoms or molecules and generating plasma, forming an electron cyclotron resonance region within the plasma chamber 11. An opening 15 facing the ion beam channel is provided within the plasma chamber 11. When the potential of a positively charged ion beam passing near the plasma chamber 11 is greater than the potential of the plasma chamber 11, electrons in the electron cyclotron resonance region are attracted by the electric field formed by the ion beam and ejected from the opening 15. The low-energy electrons ejected from the opening 15 interact with the positively charged ion beam, neutralizing the space charge of the ion beam and reducing the divergence caused by the space charge. Simultaneously, electrons following the ion beam to the silicon wafer surface neutralize the accumulated positive charge, protecting the devices on the silicon wafer from damage caused by electrostatic discharge (ESD).
[0032] The microwave plasma gun creates an electron cyclotron resonance region. The core technology is to use the resonance effect of the magnetic field and the microwave electric field to efficiently accelerate electrons, thus creating conditions for plasma generation.
[0033] The principle is as follows: In the plasma chamber 11, a static magnetic field of a specific intensity (such as a magnetic field of about 87.5 mT corresponding to 2.45 GHz microwave) is first applied, causing electrons to gyrate in the magnetic field. Then, microwaves are introduced, and when the frequency of the alternating electric field is consistent with the electron gyratory frequency, the electrons enter a resonant state and can continuously absorb energy from the microwaves, rapidly accelerating to a level sufficient to ionize the gas.
[0034] Accelerated high-energy electrons collide with neutral gas molecules within plasma chamber 11, ionizing them into ions and electrons to form plasma. The specific spatial region where electron cyclotron resonance occurs is the electron cyclotron resonance region. This region can stably maintain high-density plasma, providing a foundation for subsequent processes such as particle extraction and charge neutralization.
[0035] Inside the plasma chamber 11, microwaves are input from one end (microwave input 16), and gas is input from the other end (gas input 17). The power of the microwaves decreases from microwave input 16 to gas input 17. Because gas molecules have a longer free path in a vacuum, and the width of the opening 15 for releasing electrons is uniformly distributed from microwave input 16 to gas input 17, gas molecules are evenly distributed within the plasma chamber 11. This results in the electron cyclotron resonance region forming only in a localized area. Please refer to [reference needed]. Figure 2 ,exist Figure 2 In the diagram, the region pointed to by the line connecting the ECR regions is the electron cyclotron resonance region, while the remaining parts are other regions within plasma chamber 11. Figure 2The rectangular section on the right is an opening through which electrons escape and travel with the ion beam to the silicon wafer surface to neutralize the positive charge accumulated there. The formation of the electron cyclotron resonance region indicates, on the one hand, the interaction of gas and microwaves to form plasma, where very few molecules or atoms exist, thus reducing leakage; on the other hand, the magnetic field generated by the electron cyclotron resonance region and the electric field in the plasma exert a certain confinement effect on the nearby gas, further reducing leakage. However, gas is prone to leakage at the opening 15 where the electron cyclotron resonance region does not form, for example... Figure 2 Inert gas molecules or atoms (such as xenon molecules or atoms) leak out of the plasma chamber, such as the ion beam channel, at the lower end of the opening.
[0036] Gas leaks can lead to:
[0037] 1. When inert gas molecules or atoms leak into the ion beam channel, the number of gas molecules in the ion beam channel increases, leading to a decrease in vacuum and disrupting the original balance. To restore or maintain the target vacuum, the vacuum pump must increase its pumping power (or extend its operating time) to continuously remove the leaked xenon molecules. At this time, the actual pumping volume of the vacuum pump is much higher than normal operating conditions, and it is under an extra load. The lifespan of the vacuum pump is directly related to the operating intensity of its core components. The vacuum pump being under an extra load (i.e., increased load) leads to a reduction in its lifespan.
[0038] 2. The large strip-shaped opening 15 leads to rapid loss of inert gas. The inert gas in the plasma chamber 11 is insufficient to maintain the gas pressure required for plasma generation, resulting in low plasma generation efficiency. The large strip-shaped opening also causes rapid loss of inert gas. In order to maintain the gas pressure inside the plasma gun, the gas supply system needs to replenish inert gas at a higher frequency, resulting in high inert gas consumption and low utilization. The high-frequency replenishment of inert gas brings significant airflow disturbance, which may cause instability in the electron flow escaping to the ion beam channel, thereby affecting the stability of the ion beam channel, the uniformity of the ion beam within the ion beam channel, leading to instability in the final neutralization reaction, and also affecting the service life of the microwave plasma gun.
[0039] 3. There is a lot of inert gas leakage. In order to maintain the ionization effect inside the plasma gun, higher microwave power is required. Microwave costs are high and microwave lifespan is short.
[0040] 4. Inert gas molecules or atoms leaking into the ion beam channel collide with ions, resulting in energy loss of the ion beam.
[0041] 5. The energy regulation device on the side of the microwave plasma gun closest to the ion source uses an electric field to regulate the energy of the ions. After inert gas molecules or atoms leak out, they enter the energy regulation device. The inert gas molecules or atoms collide with the ions, causing some of the ions in the ion beam to be neutralized. The neutralized ions are uncharged and are not affected by the electric field of the energy regulation device. As a result, the energy of the neutralized ions is not regulated, which does not meet the predetermined injection energy, leading to energy contamination. Ultimately, it fails to meet the accuracy requirements for ion implantation in the chip manufacturing process.
[0042] To address the aforementioned problems, this utility model provides a microwave plasma gun, please refer to... Figure 3 , Figure 3 A schematic diagram of a microwave plasma gun provided in an embodiment of this utility model.
[0043] like Figure 3 As shown, the microwave plasma gun includes: a plasma chamber 21;
[0044] The plasma chamber 21 is used to contain microwaves and gas, and an electron cyclotron resonance region A is formed within the plasma chamber 21.
[0045] At least one electron escape hole 24 is provided on the side wall of the plasma chamber 21. Along the axial direction X of the electron escape hole 24, the position of the electron escape hole 24 corresponds coaxially to the position of the electron cyclotron resonance region A. Furthermore, in the direction perpendicular to the axial direction Y, the total cross-sectional area of the electron escape hole 24 is smaller than the cross-sectional area of the electron cyclotron resonance region A. Here, the cross-sectional area refers to the projected cross-sectional area along the depth direction of the electron escape hole 24 (i.e., the axial direction X of the electron escape hole 24).
[0046] In this embodiment of the invention, on the one hand, the setting position of the electron escape hole 24 is adjusted, and on the other hand, the total cross-sectional area of the electron escape hole 24 is limited so that the electron escape hole 24 can accurately correspond to the formation position of the electron cyclotron resonance region, and gas leakage can be avoided by setting a smaller total cross-sectional area, thereby significantly reducing gas leakage and improving the working performance of the plasma gun.
[0047] As can be seen, the microwave plasma gun provided in this embodiment of the present invention, by adjusting the setting position of the electron escape hole 24, makes the position of the electron escape hole 24 coaxially corresponding to the position of the electron cyclotron resonance region A along the axial direction X of the electron escape hole. This allows the possible leakage path of the gas to approach the electron cyclotron resonance region A. If gas attempts to escape from the electron escape hole 24, it will inevitably pass through the electron cyclotron resonance region A. Passing through the electron cyclotron resonance region A means that there is a high probability of ionization to form plasma. The ionized plasma has a positive... The electron beam, being of the same polarity, repels the external ion beam channel, preventing gas from escaping through the electron escape hole 24 and reducing gas leakage. Furthermore, in this invention, the total cross-sectional area of the electron escape hole 24 is smaller than the cross-sectional area of the electron cyclotron resonance region A along the axial direction Y. This ensures that the electron escape hole 24 and its surrounding area are completely within the region of the electron cyclotron resonance region A, further enhancing the gas leakage-resistant effect caused by the coaxial alignment of the electron escape hole 24 and the electron cyclotron resonance region A along the axial direction X of the electron escape hole. Simultaneously, because the electron escape hole 24 precisely corresponds to the electron cyclotron resonance region A, electrons generated in the electron cyclotron resonance region A do not need to migrate long distances; they can be efficiently extracted directly through the electron escape hole 24, improving the effective electron utilization rate and avoiding the damage to the cavity wall that occurs during long-distance diffusion within the plasma chamber in related technologies. Therefore, the technical solution provided by this embodiment can reduce gas leakage within the plasma chamber and improve the working performance of the microwave plasma gun.
[0048] In one embodiment, in a plane perpendicular to the depth direction of the electron evacuation aperture 24, the projection of the electron evacuation aperture 24 onto the plane is located within the projection outline of the electron cyclotron resonance region A onto the plane. That is, the projections of the electron evacuation aperture 24 and the electron cyclotron resonance region A onto the plane have a cross-sectional area greater than the total cross-sectional area of the electron evacuation aperture 24.
[0049] like Figure 3 As shown, the axial direction of the electron escape hole 24 (i.e., the depth direction of the electron escape hole 24) is the direction indicated by X.
[0050] In a plane perpendicular to the depth direction of the electron cyclotron resonance region A, the cross-sectional area formed by the projected outline of the electron cyclotron resonance region A is larger than the cross-sectional area formed by the projected outline of the electron cyclotron resonance region A. This ensures that the position of the electron cyclotron resonance region A is precisely aligned with the position of the electron cyclotron resonance region A, preventing the opening of the electron cyclotron resonance region A from being too large, while also satisfying the normal emission of electrons.
[0051] Corresponding to the aforementioned technical problems, since the electron vent hole 24 of the microwave plasma gun provided by this utility model has a smaller opening area than that in related technologies (based on the foregoing discussion, the opening area in related technologies is larger than the cross-sectional area of the electron cyclotron resonance region, thus causing gas leakage; in the direction perpendicular to the axial direction Y, the total cross-sectional area of the electron vent hole 24 of the microwave plasma gun of this utility model is smaller than the cross-sectional area of the electron cyclotron resonance region A, thus reducing gas leakage), the following technical effects can be achieved:
[0052] 1. Very little xenon molecules (i.e., the aforementioned inert gas) leak into the ion beam channel, which does not affect the vacuum level. The workload of the vacuum pump is relatively small, thus improving the service life of the vacuum pump.
[0053] 2. The smaller electron escape hole 24 can limit the rapid loss of inert gas, and the gas in the plasma chamber 21 can maintain the gas pressure required to generate plasma, thereby improving the plasma generation efficiency.
[0054] 3. Very few inert gas molecules or atoms leak into the ion beam channel, so the gas supply system does not need to replenish inert gas at a high frequency, reducing the consumption of inert gas and increasing its utilization rate.
[0055] 4. The low-frequency inert gas replenishment results in less airflow disturbance and a more stable electron flow, which in turn leads to more stable neutralization of the ion beam, better uniformity of the ion beam, and an extended lifespan for the microwave plasma gun.
[0056] 5. With minimal inert gas leakage and sufficient inert gas supply, relatively low microwave power can be used. This allows for the generation of a sufficient electron flow, reduces microwave costs, and extends the microwave's lifespan.
[0057] 6. The ion beam 25 will not suffer energy loss due to collisions with inert gas molecules or atoms.
[0058] 7. Very few inert gas molecules or atoms enter the energy regulation device, so there will be no collision between inert gas molecules or atoms and the ion beam that would cause some ions to be neutralized. All ions can be affected by the electric field of the energy regulation device, thereby meeting the predetermined injection energy and avoiding energy pollution.
[0059] In the charge neutralization scenario of using a microwave plasma gun for chip manufacturing, the position, shape, and size of the electron cyclotron resonance region A within the plasma chamber 21 are dynamically affected by the following core factors.
[0060] 1. Static magnetic field strength and uniformity
[0061] The formation of electron cyclotron resonance region A depends on the resonance conditions of the static magnetic field and the microwave field. When the intensity of the static magnetic field changes due to magnet aging, power supply fluctuations or active adjustment, the position of electron cyclotron resonance region A will migrate along the direction of the magnetic field gradient.
[0062] 2. Gas flow rate and gas pressure
[0063] When the gas flow rate exceeds a critical value, the density of the neutral gas increases significantly, causing the O-wave cutoff region to cover the electron cyclotron resonance region. Microwave energy cannot be effectively coupled to electrons, and the electron cyclotron resonance region may shrink or even disappear. In addition, increased gas pressure enhances electron-neutral particle collisions, shortens the electron free path, and limits the axial expansion of the electron cyclotron resonance region.
[0064] 3. Gas types and ionization energy
[0065] The difference in ionization energy of different gases (such as Ar, N2, and O2) can alter plasma generation efficiency. For example, gases with lower ionization energies (such as Ar) are more likely to form electron cyclotron resonance regions under the same magnetic field and power, and their plasma density peaks may occur at higher magnetic field strengths.
[0066] 4. Microwave power
[0067] Increasing microwave power raises electron energy and expands the spatial range of the electron cyclotron resonance region.
[0068] The aforementioned factors do not exist independently, but rather influence the electron cyclotron resonance region through complex nonlinear coupling. For example, when the gas flow rate increases, if the microwave power is simultaneously increased to maintain ECR conditions, the electron cyclotron resonance region may remain stable; however, if the power is not adjusted in time, the O-wave cutoff effect will cause the electron cyclotron resonance region to shrink. Furthermore, magnetic field adjustment and plasma chamber 21 geometry optimization need to be carried out in tandem to avoid excessive shift or dispersion of the electron cyclotron resonance region A due to a change in a single parameter.
[0069] The O-wave cutoff effect refers to the phenomenon where, when microwaves propagate in plasma, a specific polarization mode (O-wave) cannot continue to propagate due to the plasma density reaching a critical value, resulting in an interruption of energy transmission.
[0070] Since the shape, size, and position of the electron cyclotron resonance region A may change, the shape, size, and position of the electron escape hole 24 in this embodiment of the present invention will change based on the change of the electron cyclotron resonance region. The following embodiments are used to further illustrate the microwave plasma gun provided in this embodiment of the present invention.
[0071] Example 1
[0072] In this first embodiment, the cross-sectional shape of the electron escape hole 24 changes with the change of the electron cyclotron resonance region.
[0073] In one embodiment, the cross-sectional shape of the electron effluent 24 includes one or more of the following: circular, elliptical, triangular, and rectangular.
[0074] For example, when there is only one electron vent 24, the cross-sectional shape of the electron vent 24 can be any one of a circle, an ellipse, a triangle, or a rectangle; specifically, for example, the cross-sectional shape of the electron vent 24 can be consistent with the cross-sectional shape of the electron cyclotron resonance region A in the direction perpendicular to the axial direction of the electron vent 24.
[0075] When there are multiple electron escaping holes 24, the cross-sectional shape of the electron escaping holes 24 can include, for example, the same or different cross-sectional shapes of all electron escaping holes 24. Specifically, the same cross-sectional shape of all electron escaping holes 24 can mean that all electron escaping holes 24 have any one of the following cross-sectional shapes: circular, elliptical, triangular, and rectangular. Different cross-sectional shapes of the multiple electron escaping holes 24 can mean that the cross-sectional shapes of the multiple electron escaping holes 24 are multiple of the following: circular, elliptical, triangular, and rectangular. For example, the cross-sectional shape of some electron escaping holes 24 may be circular, and the cross-sectional shape of some electron escaping holes 24 may be elliptical; or, the cross-sectional shape of some electron escaping holes 24 may be triangular, and the cross-sectional shape of some electron escaping holes 24 may be rectangular; or, the cross-sectional shape of some electron escaping holes 24 may be triangular, the cross-sectional shape of some electron escaping holes 24 may be rectangular, the cross-sectional shape of some electron escaping holes 24 may be elliptical, and the cross-sectional shape of some electron escaping holes 24 may be circular. Any combination of two, three, or more shapes can be used as the cross-sectional shape of the electron escaping holes 24 in multiple cases, and the embodiments of this application do not limit this.
[0076] Optionally, the cross-sectional area of the electron escape hole 24 gradually increases from one end near the electron cyclotron resonance region A to the other end away from the electron cyclotron resonance region A.
[0077] Alternatively, the cross-sectional area of the electron effluent aperture 24 remains constant from one end near the electron cyclotron resonance region A to the other end away from the electron cyclotron resonance region A.
[0078] That is, the electron escape hole 24 can be a tapered hole (the cross-sectional area of the electron escape hole 24 gradually increases from the end of the electron escape hole 24 near the electron cyclotron resonance region A to the end away from the electron cyclotron resonance region A), or it can be a non-tapered hole, such as a cylindrical hole (the cross-sectional area of the electron escape hole 24 remains constant from the end of the electron escape hole 24 near the electron cyclotron resonance region A to the end away from the electron cyclotron resonance region A), so as to improve the design flexibility of the electron escape hole 24.
[0079] When the electron escaping orifice 24 is a tapered orifice, the total cross-sectional area of the electron escaping orifice 24 is calculated based on the smallest cross-section of the tapered orifice.
[0080] And refer to Figure 4 In other embodiments, when there are multiple electron escape holes 24, each electron escape hole 24 is provided along the extending direction Y' of the plasma chamber.
[0081] Alternatively, individual electron escape holes 24 may be provided in the extension direction X' perpendicular to the plasma chamber;
[0082] When there are multiple electron escaping holes 24, the multiple electron escaping holes 24 are arranged in a straight line, a ring, or an array.
[0083] Please refer to Figure 4 , Figure 4 This is another structural schematic diagram of the microwave plasma gun provided in this embodiment of the present invention. Figure 4 The diagram shows a microwave plasma gun with multiple electron escape holes (24). Figure 4 In the microwave plasma gun, the electron vent 24 is arranged along the extension direction Y' (i.e., the vertical direction) of the plasma chamber. However, in some other embodiments, when the microwave plasma gun has multiple electron vents 24, the electron vents 24 can be arranged perpendicular to the extension direction X' (i.e., the horizontal direction) of the plasma chamber to flexibly adjust the setting position of the electron vents 24 and ensure that the electron vents 24 can accurately correspond to the position of the electron cyclotron resonance region A.
[0084] In the case of multiple electron vent holes 24, each electron vent hole 24 is arranged in a straight line, a ring, an array, etc. in the horizontal or vertical direction, so that the setting of the electron vent holes 24 and the position of the electron cyclotron resonance region A are coaxially corresponding in the axial direction X of the electron vent holes 24, and in the direction perpendicular to the axial direction Y, the total cross-sectional area of the electron vent holes 24 is less than (i.e. will not exceed) the cross-sectional area of the electron cyclotron resonance region A.
[0085] The arrangement of the electron emanation holes 24 can be designed based on the shape of the electron cyclotron resonance region A. For example, when the cross-section of the electron cyclotron resonance region A in the axial direction Y perpendicular to the electron emanation holes 24 is circular, the arrangement of the electron emanation holes 24 can be a ring distribution. When the cross-section of the electron cyclotron resonance region A in the axial direction Y perpendicular to the electron emanation holes 24 is rectangular, the arrangement of the electron emanation holes 24 can be a linear distribution.
[0086] Example 2
[0087] In this second embodiment, the size of the electron escape hole 24 varies according to the size of the electron cyclotron resonance region A.
[0088] Based on the above discussion, since the microwave plasma gun provided in this embodiment of the present invention is based on the correlation between the position and total cross-sectional area of the electron escape hole 24 and the position and cross-sectional area of the electron cyclotron resonance region A, it can achieve the purpose of preventing gas leakage. When the total cross-sectional area of the electron escape hole 24 is smaller than the cross-sectional area of the electron cyclotron resonance region A, based on the change of the electron cyclotron resonance region A, the total cross-sectional area of the electron escape hole 24 can be positively correlated with the cross-sectional area of the electron cyclotron resonance region A, that is, a positive correlation change. For example, ensuring that the total cross-sectional area of the electron escape hole 24 is smaller than... Given the cross-sectional area of the electron cyclotron resonance region A, an increase in the cross-sectional area of the electron cyclotron resonance region A leads to an increase in the total cross-sectional area of the electron escape aperture 24. This ensures that the total cross-sectional area of the electron escape aperture 24 maintains a positive correlation with the cross-sectional area of the electron cyclotron resonance region A. Consequently, it can maximize electron escape efficiency while preventing gas leakage to the greatest extent. Since electron escape efficiency is related to the degree of neutralization of the ion beam, it also indirectly improves the degree of neutralization of the ion beam, reduces the accumulation of positive charge on the silicon wafer surface, and improves the accuracy of the ion implantation process.
[0089] For example, based on the simulation results of the electron cyclotron resonance region, the size of each electron escape hole 24 can be adaptively designed to achieve a positive correlation between the total cross-sectional area of the electron escape hole 24 and the cross-sectional area of the electron cyclotron resonance region A; alternatively, the number of electron escape holes 24 can be adaptively designed to achieve a positive correlation between the total cross-sectional area of the electron escape hole 24 and the cross-sectional area of the electron cyclotron resonance region A.
[0090] For example, the total cross-sectional area of the electron escaping aperture 24 is greater than 0 and less than 30 mm. 2In the case of a single electron vent 24, the total cross-sectional area of the electron vent 24 is equal to the cross-sectional area of the single electron vent 24, which is limited to: 0 < cross-sectional area of the single electron vent 24 < 30 square millimeters. In the case of multiple electron vents 24, the total cross-sectional area of the electron vents 24 is the sum of the cross-sectional areas of the multiple electron vents 24 (the sum of the areas of the point-like vents), which is limited to: 0 < the sum of the areas of the point-like vents < 30 square millimeters.
[0091] Example 3
[0092] In this third embodiment, the position of the electron escape hole 24 is adaptively adjusted based on the positional change of the electron cyclotron resonance region A.
[0093] Please refer to Figure 5 , Figure 5 This is another structural schematic diagram of the microwave plasma gun provided in this embodiment of the present invention. Figure 5 The microwave plasma gun also includes: baffle 26;
[0094] The baffle 26 is disposed on the outside of the electron escape hole 24 and is used to adjust the position of the exposed electron escape hole 24 according to the position of the electron cyclotron resonance region A; wherein, the exposed electron escape hole 24 can release electrons.
[0095] The baffle 26 is disposed on the outside of the electron escape hole 24, and the position of the exposed electron escape hole 24 can be adjusted according to the change of the position of the electron cyclotron resonance region A, so that electrons can escape from the exposed electron escape hole 24.
[0096] When setting multiple electron escape holes 24, the specific location of the current electron cyclotron resonance region A can be used as an example. Figure 5 At the middle position shown, the position of the baffle 26 can be adjusted so that the position of the electron escape hole 24 (exposed electron escape hole 24) that is not blocked by the baffle 26 corresponds to the position of the electron cyclotron resonance region A, thus avoiding gas leakage.
[0097] The baffle 26 is also used to adjust the number of exposed electron escape holes 24 according to the cross-sectional area of the electron cyclotron resonance region A; wherein, the exposed electron escape holes 24 can release electrons.
[0098] Please continue to refer to this. Figure 5 , Figure 5In the example shown, three electron escaping holes 24 in the middle position are exposed, such that the positions of the exposed electron escaping holes 24 along the axial direction X of the electron escaping holes 24 are coaxially corresponding to the position of the electron cyclotron resonance region A. That is, the exposed electron escaping holes 24 are adapted to the electron cyclotron resonance region A, and the total cross-sectional area of the exposed electron escaping holes 24 is smaller than the cross-sectional area of the electron cyclotron resonance region A.
[0099] The aforementioned baffle 26 can be driven by a drive mechanism, for example. For example, it can be designed with reference to a common shower head, where the baffle 26 of this utility model embodiment can be opened / closed by rotating the cover plate on the shower head during daily use. It can also be rotated to block / unblock the electron escaping hole 24, thereby adjusting the number and position of the exposed electron escaping hole 24.
[0100] Along the axial direction X of the electron escape aperture 24, the position of the electron escape aperture 24 corresponds coaxially with the position of the electron cyclotron resonance region A (the position of the electron escape aperture 24 changes based on the position of the electron cyclotron resonance region A). The resulting effect is as follows:
[0101] 1. The electron escape hole 24 is coaxially aligned with the electron cyclotron resonance region A. If an inert gas molecule or atom attempts to escape from the electron escape hole 24, it will inevitably pass through the electron cyclotron resonance region A. Passing through the electron cyclotron resonance region A means that it is highly likely to be ionized to form plasma. The ionized inert gas ions are positively charged and repel the ion beam, thus preventing them from escaping from the electron escape hole 24.
[0102] 2. The electron escaping hole 24 corresponds precisely to the electron cyclotron resonance region A. Electrons generated in the electron cyclotron resonance region A do not need to migrate long distances and can be efficiently exported directly through the electron escaping hole 24, thereby improving the effective electron utilization rate.
[0103] 3. Electrons do not need to "diffuse over a long distance" within the cavity to reach the electron escape hole 24 (due to the risk of damage to the cavity wall during long-distance diffusion).
[0104] 4. Although the electron escaping aperture 24 is much smaller than the width of the ion beam 25, after electrons are drawn out from the electron escaping aperture 24, they can automatically move to the position that needs to be neutralized under the action of the electric field formed by the ion beam 25, and can achieve a uniform neutralization effect.
[0105] It is known that in actual scenarios, the shape, size, and position of the electron cyclotron resonance region A may change simultaneously. Therefore, the microwave plasma gun provided in this embodiment of the present invention also adaptively adjusts the shape, size, position, and number of electron escape holes 24 based on the changes in the shape, size, and position of the electron cyclotron resonance region A. That is to say, the above three embodiments only illustrate that when one of the shape, size, and position of the electron cyclotron resonance region A changes, this embodiment of the present invention changes the design of the electron escape holes 24. However, when two, three, or four of the shape, size, position, and number of the electron cyclotron resonance region A change, this embodiment of the present invention will also adaptively adjust the electron escape holes 24 based on the changes in the electron cyclotron resonance region A, so that along the axial direction X of the electron escape holes 24, the position of the electron escape holes 24 is coaxially corresponding to the position of the electron cyclotron resonance region A, and in the direction perpendicular to the axial direction Y, the total cross-sectional area of the electron escape holes 24 is smaller than the cross-sectional area of the electron cyclotron resonance region A.
[0106] Please continue to refer to this. Figure 3 The microwave plasma gun provided in this embodiment of the present invention may further include: a microwave input terminal 22 and a gas input terminal 23; the microwave input terminal 22 is used to introduce microwaves into the plasma chamber 21; the gas input terminal 23 is used to introduce gas into the plasma chamber 21.
[0107] The microwave plasma gun provided in this embodiment of the utility model may further include: a conductive rod 12 (such as...) Figure 1 (As shown); the conductive rod 12 is inserted into the plasma chamber 21 from the microwave input end 22 to transmit microwave energy.
[0108] The microwave plasma gun provided in this embodiment of the present invention may further include: a dielectric tube 14 (such as...) Figure 1 (As shown in the figure); the dielectric tube 14 is sleeved around the outside of the conductive rod 12 to provide support and positioning for the conductive rod 12.
[0109] The microwave plasma gun provided in this embodiment of the present invention may further include: a microwave generator and a gas supply device; the microwave generator is connected to the microwave input terminal 22 and is used to generate and input microwaves to the microwave input terminal 22; the gas supply device is connected to the gas input terminal 23 and is used to store and input gas to the gas input terminal 23.
[0110] The microwave plasma gun provided in this embodiment of the present invention may further include: a water-cooling channel 13 (such as...). Figure 1 (As shown); the water-cooling channel 13 is located on the side wall of the plasma chamber 21 where the electron escape hole 24 is not provided, and is used for heat dissipation and cooling to maintain the stability of the microwave plasma gun.
[0111] Based on the same inventive concept, an embodiment of this utility model also provides an ion implanter that uses the microwave plasma gun described above.
[0112] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.
Claims
1. A microwave plasma gun, characterized in that, include: Plasma chamber; The plasma chamber is used to contain microwaves and gas, and an electron cyclotron resonance region is formed within the plasma chamber; At least one electron escape hole is provided on the side wall of the plasma chamber; along the axial direction of the electron escape hole, the position of the electron escape hole corresponds coaxially with the position of the electron cyclotron resonance region, and in the direction perpendicular to the axial direction, the total cross-sectional area of the electron escape hole is smaller than the cross-sectional area of the electron cyclotron resonance region.
2. The microwave plasma gun as described in claim 1, characterized in that, The total cross-sectional area of the electron escape aperture is positively correlated with the cross-sectional area of the electron cyclotron resonance region.
3. The microwave plasma gun as described in claim 2, characterized in that, The total cross-sectional area of the electron escape pore is greater than 0 and less than 30 mm. 2 .
4. The microwave plasma gun as described in claim 1, characterized in that, In a plane perpendicular to the depth direction of the electron vent hole, the projection of the electron vent hole onto the plane lies within the projection outline of the electron cyclotron resonance region onto the plane.
5. The microwave plasma gun as described in claim 1, characterized in that, The cross-sectional shape of the electron effluent aperture includes one or more of the following: circular, elliptical, triangular, and rectangular.
6. The microwave plasma gun as described in claim 1, characterized in that, Also includes: baffle; The baffle is disposed on the outside of the electron escape hole and is used to adjust the position of the exposed electron escape hole according to the position of the electron cyclotron resonance region; wherein, electrons can escape from the exposed electron escape hole.
7. The microwave plasma gun as described in claim 6, characterized in that, The baffle is also used to adjust the number of exposed electron escape holes according to the cross-sectional area of the electron cyclotron resonance region.
8. The microwave plasma gun as described in claim 1, characterized in that, When there are multiple electron vent holes, the multiple electron vent holes are arranged in a straight line, a ring, or an array.
9. The microwave plasma gun as described in claim 1, characterized in that, The cross-sectional area of the electron effluent gradually increases from the end of the electron effluent aperture that is closer to the electron cyclotron resonance region to the end that is farther away from the electron cyclotron resonance region. Alternatively, the cross-sectional area of the electron effluent aperture remains constant from one end near the electron cyclotron resonance region to the other end away from the electron cyclotron resonance region.
10. The microwave plasma gun as described in claim 1, characterized in that, Also includes: Microwave input terminal and gas input terminal; The microwave input terminal is used to transmit microwaves into the plasma chamber; The gas input terminal is used to introduce gas into the plasma chamber.
11. The microwave plasma gun as described in claim 10, characterized in that, Also includes: A conductive rod; the conductive rod is inserted into the plasma chamber from the microwave input end for transmitting microwave energy.
12. The microwave plasma gun as described in claim 11, characterized in that, Also includes: A dielectric tube; the dielectric tube is sleeved around the outside of the conductive rod to provide support and positioning for the conductive rod.
13. The microwave plasma gun as described in claim 10, characterized in that, Also includes: Microwave generator and gas supply device; The microwave generator is connected to the microwave input terminal and is used to generate and input microwaves to the microwave input terminal. The gas supply device is connected to the gas input terminal and is used to store and input gas into the gas input terminal.
14. The microwave plasma gun as described in claim 1, characterized in that, Also includes: Water-cooled channel; the water-cooled channel is located on the side wall of the plasma chamber without electron escape holes, and is used for heat dissipation and cooling.
15. An ion implanter, characterized in that, The microwave plasma gun according to any one of claims 1-14 is used.