Microwave electron gun, method of generating electron cyclotron resonance region, and ion implanter

Abstract

The application provides a microwave electron gun, a method for generating an electron cyclotron resonance region and an ion implanter, wherein the microwave electron gun comprises: a plasma chamber; the plasma chamber has a first end and a second end; the first end is used for passing in microwaves; the second end is used for passing in gas; an escape region is arranged on the sidewall of the plasma chamber, and the particle escape efficiency of the escape region gradually decreases from the first end to the second end, wherein the particles include electrons and / or gas molecules / atoms. The microwave electron gun provided by the technical scheme reduces the leakage degree of the gas in the plasma chamber and improves the working performance of the microwave electron gun.

Description

Technical Field

[0001] This invention relates to the field of semiconductor process equipment, and more particularly to microwave electron guns, methods for generating electron cyclotron resonance regions, and ion implanters. 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 electron guns. These guns contain a plasma chamber. Microwaves (through the first end) and inert gas (through the second end) are introduced into the plasma chamber, ionizing gas atoms or molecules and generating plasma. This forms 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, the formation of the ECR region requires both gas concentration and microwave power to reach a threshold. While the gas concentration is uniformly distributed within the plasma chamber, the microwave power gradually decreases from the first end to the second end due to transmission losses. This results in the inability to form an ECR region in the middle and near the second end of the plasma chamber. Consequently, the ECR region is only formed in a portion of the plasma chamber, which cannot provide sufficient electrons for the ion beam. This affects the working performance of the microwave electron gun, thereby reducing ion implantation accuracy and device quality.

[0004] Therefore, how to improve the uniformity of ECR ​​distribution in the plasma chamber and improve the working performance of the microwave electron gun has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] This invention provides a microwave electron gun, a method for generating an electron cyclotron resonance region, and an ion implanter to improve the uniformity of ECR ​​region distribution within a plasma chamber and enhance the performance of the microwave electron gun.

[0006] In a first aspect, the present invention provides a microwave electron gun, comprising: a plasma chamber; the plasma chamber having a first end and a second end; the first end being used to introduce microwaves; and the second end being used to introduce gas.

[0007] The plasma chamber has an escape region on its side wall. From the first end to the second end, the particle escape efficiency of the escape region gradually decreases. The particles include electrons and / or gas molecules / atoms.

[0008] In a second aspect, the present invention provides a method for generating an electron cyclotron resonance region, applied to the microwave electron gun described in the first aspect, comprising:

[0009] Microwaves are introduced from the first end of the plasma chamber of the microwave electron gun, and gas is introduced from the second end of the plasma chamber of the microwave electron gun; the microwave power gradually decreases from the first end to the second end, and the gas concentration gradually increases from the first end to the second end.

[0010] The microwave power and gas concentration are complementary, so that the plasma generated by the interaction of microwave power and gas concentration is balanced at each position of the plasma chamber from the first end to the second end, forming a uniformly distributed electron cyclotron resonance region.

[0011] Thirdly, the present invention provides an ion implanter that uses a microwave electron gun as described in the first aspect.

[0012] The microwave electron gun provided by the present invention includes: a plasma chamber having a first end and a second end, the first end for introducing microwaves and the second end for introducing gas, such that the plasma chamber contains substances (microwaves and gas) capable of forming an electron cyclotron resonance region; an escape region is provided on the side wall of the plasma chamber. In the present invention, the particle escape efficiency of the escape region gradually decreases from the first end (input microwaves) to the second end (input gas). Since the particle escape efficiency is negatively correlated with the gas concentration, the gas concentration gradually increases from the first end to the second end; at the same time, under normal circumstances, the microwave power gradually decreases from the first end to the second end.

[0013] On the one hand, the aforementioned particles include electrons. The microwave power at the first end is higher than that at the second end, so the gas near the first end can be ionized in time to generate more electrons. Furthermore, the particle escape efficiency in the escape region near the first end is higher than that in the escape region near the second end, meaning that the electron escape efficiency in the escape region near the first end is higher. More electrons are promptly drawn out of the plasma chamber. To replenish the more electrons drawn out at the first end, the gas near the first end is ionized relatively more, resulting in a relatively low gas concentration. On the other hand, the electron escape efficiency in the escape region near the second end is lower than that in the escape region near the first end, resulting in fewer electrons drawn out at the second end. To replenish the fewer electrons drawn out at the second end, the gas near the second end is ionized relatively less, resulting in a relatively high gas concentration.

[0014] On the other hand, the aforementioned particles include gas molecules / atoms. From the first end to the second end, the gas molecule / atom escape (leakage) efficiency decreases, and the gas near the second end is difficult to leak out, resulting in an increase in gas concentration from the first end to the second end. There is a sufficiently high gas concentration near the second end, which can compensate for the defect that the microwave power near the second end is low and cannot form an electron cyclotron resonance region, so that an ECR region can also be formed near the second end.

[0015] Therefore, since the particle escape efficiency of the escape region of the present invention gradually decreases from the first end to the second end, a uniformly distributed electron cyclotron resonance region can be formed in the plasma chamber. The uniformly distributed electron cyclotron resonance region enables most of the gas in the plasma chamber to form plasma under the action of microwaves, thus reducing the degree of gas leakage. At the same time, the remaining small part of the gas can also be constrained by the electron cyclotron resonance region, further reducing the degree of gas leakage. The uniformly distributed electron cyclotron resonance region can also provide more electrons for the ion beam neutralization process, thereby improving the working performance of the microwave electron gun. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a microwave electron gun in related technologies;

[0017] Figure 2 This is a schematic diagram showing the distribution of gas concentration and microwave power inside a microwave electron gun in related technologies;

[0018] Figure 3 This is a schematic diagram showing the distribution of the electron cyclotron resonance region in the original plasma chamber of a microwave electron gun in related technologies;

[0019] Figure 4 This is a schematic diagram of a microwave electron gun provided in an embodiment of the present invention;

[0020] Figure 5a A schematic diagram showing the distribution of gas concentration and microwave power within the plasma chamber of a microwave electron gun provided in an embodiment of the present invention;

[0021] Figure 5b This is a schematic diagram of the distribution of the electron cyclotron resonance region in the plasma chamber of Example 1;

[0022] Figure 6 This is another schematic diagram of the microwave electron gun provided in an embodiment of the present invention;

[0023] Figure 7 This is another structural schematic diagram of the microwave electron gun provided in an embodiment of the present invention;

[0024] Figure 8 This is another structural schematic diagram of a microwave electron gun provided in an embodiment of the present invention;

[0025] Figure 9 This is a schematic diagram of the structure of a microwave electron gun provided in an embodiment of the present invention;

[0026] Figure 10 This is a schematic flowchart of a method for generating an electron cyclotron resonance region provided in an embodiment of the present invention.

[0027] Figure label:

[0028] A schematic diagram of the structure of a microwave electron gun in related technologies ( Figure 1 , Figure 2 , Figure 3 ):

[0029] 11. Primitive plasma chamber; 12. Opening; 13. Microwave input terminal; 14. Gas input terminal;

[0030] A schematic diagram of the structure of the microwave electron gun provided in this embodiment of the invention ( Figure 4 , 6 7, 8, 9):

[0031] 21. Plasma chamber; 22. Exit port; 23. First end; 24. Second end. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] Ion implantation is a crucial doping process in the chip manufacturing 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 manufacturing process can be broadly divided into three core stages:

[0034] 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.

[0035] Chip manufacturing stage: Based on the layout file, 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. Ion implantation is the core step of the "doping process" in the manufacturing stage, used to precisely control the electrical properties (N-type / P-type doping) of specific areas of the silicon wafer.

[0036] 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.

[0037] 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.

[0038] 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 electron guns (e.g., microwave electron guns) positioned in front of the silicon wafer along the path of the ion beam (ion beam channel). This allows electrons ejected from the electron 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.

[0039] A microwave electron 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 charged particles to the silicon wafer surface, the positive charge remaining during ion implantation is counteracted, thus avoiding device damage or process failure caused by charge accumulation.

[0040] Specifically, Figure 1 This is a schematic diagram of a microwave electron gun in related technologies. Please refer to it. Figure 1The microwave electron gun contains a primary plasma chamber 11. An inert gas (such as xenon) is introduced into the primary plasma chamber 11 through the gas input terminal 14, and microwaves are introduced into the primary plasma chamber 11 through the microwave input terminal 13, ionizing the gas atoms or molecules and generating plasma, forming an electron cyclotron resonance region within the primary plasma chamber 11. An opening 12 facing the ion beam channel is provided within the primary plasma chamber 11. When the potential of a positively charged ion beam passing near the primary plasma chamber 11 is greater than the potential of the primary 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 12. The low-energy electrons ejected from the opening 12 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).

[0041] The microwave electron gun forms an electron cyclotron resonance region. Its core is to use the resonance effect of the magnetic field and the microwave electric field to efficiently accelerate electrons, creating conditions for plasma generation.

[0042] The principle is as follows: In the original 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.

[0043] The accelerated high-energy electrons collide with the neutral gas molecules in the original 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 basis for subsequent electron extraction and charge neutralization processes.

[0044] Of course, the "electron cyclotron frequency" and the "alternating electric field frequency" being the same merely open a bridge for energy transfer: electrons continuously absorb energy from microwaves. However, absorbing energy does not mean that electrons can collide with gas molecules to form plasma; sufficient microwave power and gas concentration are also required. If the microwave power is insufficient, the electrons will not absorb enough energy to break apart the gas molecules, or only a few electrons will absorb enough microwave energy to produce a very small amount of plasma, which will also fail to form an ECR region. If the gas concentration is insufficient, the plasma produced by electron collisions will be minimal, making it difficult to form a large-area ECR region that meets the requirements.

[0045] Within the primary plasma chamber 11, microwaves are input from one end (microwave input 13), and gas is input from the other end (gas input 14). The microwave power decreases from microwave input 13 to gas input 14. The width of the opening 12 for releasing electrons is uniformly distributed from microwave input 13 to gas input 14. The gas at microwave input 13 is ionized and consumed, while the gas at gas input 14 is consumed due to leakage. This results in a uniform distribution of gas molecules within the primary plasma chamber 11, leading to the formation of an electron cyclotron resonance region only in a localized area. Please refer to [reference needed]. Figure 2 , Figure 2 This is a schematic diagram illustrating the distribution of gas concentration and microwave power within a microwave electron gun in related technologies. The arrows indicate the direction from microwave input terminal 13 to gas input terminal 14. Figure 2 In the original plasma chamber, the gas concentration is uniformly distributed from microwave input 13 to gas input 14. However, due to transmission loss, the microwave power gradually decreases from microwave input 13 to gas input 14. At microwave input 13, the microwave power is sufficient to provide enough energy for electrons to collide with gas molecules and form plasma, i.e., the ECR region. Near the middle of the original plasma chamber and near gas input 14, the microwave power is significantly reduced. Only a few electrons have enough energy to collide with gas molecules, generating some plasma, but not enough to form a large enough ECR region. Therefore, near the middle of the original plasma chamber and near gas input 14, the gas remains mostly in molecular form.

[0046] Please refer to Figure 3 , Figure 3 This is a schematic diagram showing the distribution of the electron cyclotron resonance region in the original plasma chamber within a microwave electron gun in related technologies. Figure 3 In the blank area on the left, the direction indicated by the arrow is from microwave input terminal 13 to gas input terminal 14. The area pointed to by the line connecting the ECR regions is the electron cyclotron resonance region. It can be seen that the ECR region is formed only near microwave input terminal 13, and the rest of the original plasma chamber does not form an ECR region. Figure 3The rectangular portion pointed to by the line connecting openings 12 on the right is opening 12. Electrons escape through opening 12 and reach the silicon wafer surface along with the ion beam to neutralize the positive charge accumulated on the silicon wafer surface by the ion beam. The formation of the electron cyclotron resonance region (ECR) indicates, on the one hand, that the interaction between gas and microwaves forms plasma, creating an ECR region. Within the ECR region, there are very few molecules or atoms of gas, thus reducing gas leakage. On the other hand, the magnetic field generated by the ECR region and the electric field in the plasma exert a certain confinement effect on the nearby gas, which can also reduce gas leakage to some extent. However, at openings 12 where no ECR region has formed, gas, such as inert gas molecules or atoms (e.g., [missing information]), is more likely to leak due to the larger size of opening 12. Figure 3 The xenon molecules or atoms shown leak out of the original plasma chamber at the lower end of the opening 12 and enter the ion beam channel.

[0047] The inability to form a uniform ECR area can also lead to the following defects:

[0048] 1. The gas in the middle and bottom of the original plasma chamber 11 is not ionized, and this part of the gas is wasted; and there is a possibility of leakage from the opening 12, which will lead to a series of more defects (for example, it will cause the gas input end 14 to need to input more gas into the original plasma chamber 11, resulting in excessive consumption of the gas input end 14 device and reduced lifespan).

[0049] 2. The microwaves in the middle and bottom of the original plasma chamber 11 were not utilized, and this part of the microwaves was wasted.

[0050] 3. If the ECR area is too concentrated, it may cause etching of the cavity wall, resulting in damage to the microwave electron gun. In addition, the etched particles will gradually deposit on the sidewall near the opening 12. Over time, the opening 12 will gradually decrease due to the increase of deposited material, resulting in a gradual decrease in the electron extraction amount (electron escape efficiency). Consequently, the positive charge on the wafer (silicon wafer) cannot be neutralized according to the process requirements, thus failing to meet the process requirements.

[0051] To address the aforementioned problems, embodiments of the present invention provide a microwave electron gun to improve the uniformity of ECR ​​region distribution within the plasma chamber and enhance the working performance of the microwave electron gun.

[0052] Please refer to Figure 4 , Figure 4 This is a schematic diagram of a microwave electron gun provided in an embodiment of the present invention.

[0053] like Figure 4As shown, the microwave electron gun includes: a plasma chamber 21; the plasma chamber 21 has a first end 23 and a second end 24; the first end 23 is used to introduce microwaves; the second end 24 is used to introduce gas.

[0054] The plasma chamber 21 has an escape region A on its side wall. From the first end 23 to the second end 24, the particle escape efficiency of the escape region A gradually decreases. The particles include electrons and / or gas molecules / atoms.

[0055] The particle escape efficiency of the escape region A gradually decreases from the first end 23 to the second end 24, or it can be that the particle escape resistance of the escape region A gradually increases from the first end 23 to the second end 24.

[0056] The aforementioned particles include electrons, and / or gas molecules / atoms (gas molecules or gas atoms), referring to:

[0057] 1. The particles include electrons. The electron emission efficiency in the emission region A near the first end 23 is higher than that in the emission region A near the middle of the plasma chamber 21 and near the second end 24. More electrons are drawn out near the first end 23. To compensate for the electrons drawn out near the first end 23, more gas is ionized near the first end 23, resulting in a relatively low gas concentration. Fewer electrons are drawn out near the middle of the plasma chamber 21 and near the second end 24. To compensate for the fewer electrons drawn out near the middle of the plasma chamber 21 and near the second end 24, less gas is ionized near the middle of the plasma chamber 21 and near the second end 24, resulting in a relatively high gas concentration.

[0058] 2. The particles include gas molecules / atoms. From the first end 23 to the second end 24, the gas molecule / atom escape (leakage) efficiency decreases, resulting in an increase in gas concentration from the first end 23 to the second end 24. The gas concentration is highest near the second end 24. This can compensate for the lower microwave power near the middle of the plasma chamber 21 and near the second end 24, so that ECR regions can also be formed near the middle of the plasma chamber 21 and near the second end 24.

[0059] Based on the particle composition within the plasma chamber 21 described above, the particle escape efficiency of the escape region A gradually decreases from the first end 23 to the second end 24, including:

[0060] 1. From the first end 23 to the second end 24, the electron escape efficiency of the escape region A gradually decreases;

[0061] 2. From the first end 23 to the second end 24, the escape efficiency of gas molecules / gas atoms in the escape region A gradually decreases;

[0062] 3. From the first end 23 to the second end 24, the electron emission efficiency of the emission region A gradually decreases, and the gas molecule emission efficiency of the emission region A gradually decreases.

[0063] 4. From the first end 23 to the second end 24, the electron emission efficiency of the emission region A gradually decreases, and the gas atom emission efficiency of the emission region A gradually decreases;

[0064] 5. From the first end 23 to the second end 24, the electron emission efficiency of the emission region A gradually decreases, and the gas molecule emission efficiency and gas atom emission efficiency of the emission region A gradually decrease.

[0065] The microwave electron gun provided in this embodiment of the invention includes: a plasma chamber 21, the plasma chamber 21 having a first end 23 and a second end 24, the first end 23 for introducing microwaves, and the second end 24 for introducing gas, so that the plasma chamber 21 contains substances (microwaves and gas) capable of forming an electron cyclotron resonance region; an escape region A is provided on the side wall of the plasma chamber 21. In this embodiment of the invention, the particle escape efficiency of the escape region A gradually decreases from the first end 23 (input microwaves) to the second end 24 (input gas). Since the particle escape efficiency is negatively correlated with the gas concentration, the gas concentration gradually increases from the first end 23 to the second end 24; at the same time, under normal circumstances, the microwave power gradually decreases from the first end 23 to the second end 24.

[0066] On the one hand, the aforementioned particles include electrons. The microwave power of the first end 23 is higher than that of the second end 24. The gas near the first end 23 can be ionized in time to generate more electrons. Furthermore, the particle escape efficiency of the escape region A near the first end 23 is higher than that of the escape region A near the second end 24. In other words, the electron escape efficiency of the escape region A near the first end 23 is higher. More electrons are promptly drawn out of the plasma chamber 21. In order to replenish the more electrons drawn out of the first end 23, the gas near the first end 23 is ionized relatively more, resulting in a relatively low gas concentration. On the other hand, the electron escape efficiency of the escape region A near the second end 24 is lower than that of the escape region A near the first end 23. Fewer electrons are drawn out near the second end 24. In order to replenish the fewer electrons drawn out near the second end 24, the gas near the second end 24 is ionized relatively less, resulting in a relatively high gas concentration.

[0067] On the other hand, the aforementioned particles also include gas molecules / atoms. From the first end 23 to the second end 24, the gas molecule / atom escape (leakage) efficiency decreases, and the gas near the second end 24 is difficult to leak out, resulting in an increase in gas concentration from the first end 23 to the second end 24. There is a sufficiently high gas concentration near the second end 24, which can compensate for the defect that the microwave power near the second end 24 is low and cannot form an electron cyclotron resonance region, so that an ECR region can also be formed near the second end 24.

[0068] Since the particle escape efficiency of the escape region A in this embodiment of the invention gradually decreases from the first end 23 to the second end 24, the technical solution provided by this embodiment of the invention can form a uniformly distributed electron cyclotron resonance region in the plasma chamber 21. This uniformly distributed electron cyclotron resonance region allows most of the gas in the plasma chamber 21 to form plasma under the action of microwaves, thus reducing gas leakage. The remaining small portion of gas can also be constrained by the electron cyclotron resonance region, further reducing gas leakage. The uniformly distributed electron cyclotron resonance region can also serve as a confinement area for ion beams (such as...). Figure 4 The neutralization process (pointed to by arrow B) provides more electrons, thereby improving the performance of the microwave electron gun.

[0069] Please combine Figure 4 ,refer to Figure 5a , Figure 5a This is a schematic diagram showing the distribution of gas concentration and microwave power within the plasma chamber 21 of the microwave electron gun provided in an embodiment of the present invention.

[0070] like Figure 5a As shown, the arrows point in the direction from the first end 23 to the second end 24. In the microwave electron gun provided in this embodiment of the invention, since the particle escape efficiency of the escape region A gradually decreases from the first end 23 to the second end 24, the closer to the first end 23, the greater the number of particles escaped from the escape region A per unit time. The gas is consumed by high-speed and efficient ionization, resulting in a lower concentration of gas molecules / atoms in the plasma chamber 21 near the first end 23. The closer to the second end 24, the fewer the number of particles escaped from the escape region A per unit time, and the slower the gas is consumed, resulting in a higher concentration of gas molecules / atoms. Therefore, the gas concentration gradually increases from the first end 23 to the second end 24, while the microwave power gradually decreases from the first end 23 to the second end 24, presenting the gas concentration and microwave power distribution shown in Figure 5. Because the gas concentration and microwave power are complementary (the microwave power and gas concentration are complementary, so that the plasma generated by the interaction of microwave power and gas concentration at each position of the plasma chamber 21 from the first end 23 to the second end 24 is balanced, forming a uniformly distributed electron cyclotron resonance region), specifically:

[0071] Near the first end 23: strong microwave power (above the microwave power threshold) + low gas density (concentration) (but still above the lower limit of the gas concentration threshold required for gas ionization) → satisfying the dual thresholds (microwave power threshold and gas concentration threshold) → the first end 23 forms an ECR region;

[0072] Middle section: Medium microwave power + medium gas density → satisfying dual thresholds → forming an ECR region in the middle section;

[0073] Near the second end 24: weak microwave power (still higher than the microwave power threshold required for gas ionization) + high gas density (far higher than the gas concentration threshold; although only a few electrons absorb enough microwave energy, due to the high concentration of gas molecules, enough gas molecules are bombarded to form enough plasma) → satisfying the dual thresholds → forming an ECR region near the second end 24.

[0074] Therefore, the microwave electron gun provided in this embodiment of the invention achieves the effect of forming uniformly distributed ECR regions at various locations in the plasma chamber 21, avoiding the problem of etching on the sidewall of the plasma chamber 21 near the ECR region caused by the ECR regions being concentrated only at the first end 23.

[0075] Next, several embodiments of the microwave electron gun provided in the present invention will be listed to further explain and illustrate the microwave electron gun provided in the present invention.

[0076] Example 1

[0077] Please continue to refer to this. Figure 4 ,exist Figure 4 In this context, the particle escape efficiency of the escape region A gradually decreases from the first end 23 to the second end 24, for example, it may include:

[0078] The escape region A is provided with multiple escape holes 22, and the area of ​​each escape hole 22 gradually decreases from the first end 23 to the second end 24.

[0079] Please refer to Figure 4 ,exist Figure 4 In this process, the number of escape holes 22 can be, for example, four, meaning that the escape region A has four escape holes 22. From the first end 23 to the second end 24, the area of ​​the four escape holes 22 gradually decreases. Larger area escape holes 22 make it easier for particles to escape, while smaller area escape holes 22 make it more difficult for particles to escape.

[0080] Thus, at the first end 23, a greater number of electrons are drawn out of the plasma chamber 21. To compensate for the greater number of electrons drawn out at the first end 23, the gas near the first end 23 is ionized more, resulting in a relatively low gas concentration. Near the middle of the plasma chamber 21 and near the second end 24, the leakage efficiency of gas molecules / atoms decreases, causing the gas concentration near the middle of the plasma chamber 21 and near the second end 24 to increase. This can compensate for the deficiency that the microwave power is too low near the middle of the plasma chamber 21 and near the second end 24 to form an electron cyclotron resonance region, thus enabling the formation of an ECR region near the middle of the plasma chamber 21 and near the second end 24.

[0081] It is understood that the number of escaping holes 22 in the microwave electron gun provided in Embodiment 1 can be, for example, three, five or more, and the embodiments of the present invention do not limit this.

[0082] Please refer to Figure 5b , Figure 5b This is a schematic diagram showing the distribution of the electron cyclotron resonance region in the plasma chamber of Example 1. Figure 5b The diagram shown is a schematic representation of the ECR region distribution obtained from simulation of the scheme in Example 1. Figure 3 In comparison, it can be clearly seen that the ECR region extends towards the second end 24, and its uniformity is significantly better than that of related technologies.

[0083] Example 2

[0084] Please refer to Figure 6 , Figure 6 This is another schematic diagram of the microwave electron gun provided in an embodiment of the present invention.

[0085] like Figure 6 As shown, the particle escape efficiency of the escape region A gradually decreases from the first end 23 to the second end 24, for example, it may include:

[0086] The escape region A is provided with multiple escape holes 22, each escape hole 22 including a different number of sub-escape holes, and from the first end 23 to the second end 24, the number of sub-escape holes included in each escape hole 22 gradually decreases.

[0087] exist Figure 6In this process, the number of escape holes 22 can be, for example, four. The escape region A has four escape holes 22, each including a different number of sub-escape holes. From the first end 23 to the second end 24, the number of sub-escape holes in each escape hole 22 gradually decreases. The escape hole 22 near the first end 23 has four sub-escape holes, while the escape hole 22 near the second end 24 has only one sub-escape hole. An escape hole 22 with a larger number of sub-escape holes results in higher particle escape efficiency, while an escape hole 22 with a smaller number of sub-escape holes results in lower particle escape efficiency.

[0088] Thus, at the first end 23, a greater number of electrons are drawn out of the plasma chamber 21. To compensate for the greater number of electrons drawn out at the first end 23, the gas near the first end 23 is ionized more, resulting in a relatively low gas concentration. Near the middle of the plasma chamber 21 and near the second end 24, the leakage efficiency of gas molecules / atoms decreases, causing the gas concentration near the middle of the plasma chamber 21 and near the second end 24 to increase. This can compensate for the deficiency that the low power near the middle of the plasma chamber 21 and near the second end 24 prevents the formation of an electron cyclotron resonance region, thus enabling the formation of an ECR region near the middle of the plasma chamber 21 and near the second end 24.

[0089] It is understood that the number of exit holes 22 in the microwave electron gun provided in Embodiment 2 can be, for example, three, five or more, and the embodiments of the present invention do not limit this.

[0090] Example 3

[0091] Please refer to Figure 7 , Figure 7 This is another schematic diagram of the structure of the microwave electron gun provided in an embodiment of the present invention.

[0092] like Figure 7 As shown, the particle escape efficiency of the escape region A gradually decreases from the first end 23 to the second end 24, for example, it may include:

[0093] The escape area A is provided with multiple escape holes 22, and the length of each escape hole 22 gradually increases from the first end 23 to the second end 24.

[0094] exist Figure 7 In this process, the number of escape holes 22 can be, for example, four. The escape region A has four escape holes 22, and the length of the four escape holes 22 gradually increases from the first end 23 to the second end 24. A shorter escape hole 22 makes it easier for particles to escape, while a longer escape hole 22 makes it more difficult for particles to escape.

[0095] Thus, at the first end 23, a greater number of electrons are drawn out of the plasma chamber 21. To compensate for the greater number of electrons drawn out at the first end 23, the gas near the first end 23 is ionized more, resulting in a relatively low gas concentration. Near the middle of the plasma chamber 21 and near the second end 24, the leakage efficiency of gas molecules / atoms decreases, causing the gas concentration near the middle of the plasma chamber 21 and near the second end 24 to increase. This can compensate for the deficiency that the low power near the middle of the plasma chamber 21 and near the second end 24 prevents the formation of an electron cyclotron resonance region, thus enabling the formation of an ECR region near the middle of the plasma chamber 21 and near the second end 24.

[0096] It is understood that the number of escaping holes 22 in the microwave electron gun provided in Embodiment 3 can be, for example, three, five or more, and the embodiments of the present invention do not limit this.

[0097] Example 4

[0098] Please refer to Figure 8 , Figure 8 This is another structural schematic diagram of a microwave electron gun provided in an embodiment of the present invention.

[0099] like Figure 8 As shown, the particle escape efficiency of the escape region A gradually decreases from the first end 23 to the second end 24, for example, it may include:

[0100] The escape zone A is provided with multiple escape holes 22, and the tortuosity of each escape hole 22 gradually increases from the first end 23 to the second end 24.

[0101] exist Figure 8 In this process, the number of escape holes 22 can be, for example, four. Escape region A has four escape holes 22, and the tortuosity of the four escape holes 22 gradually increases from the first end 23 to the second end 24. From the first end 23 to the second end 24, the tortuosity of the escape holes 22 becomes increasingly complex; for example, from the first end 23 to the second end 24, the number of bends in the escape holes 22 increases (the tortuosity becomes increasingly greater). The straighter the escape hole 22 (the smallest tortuosity, the fewest bends), the easier it is for particles to escape, and the greater the electron dose escaped per unit time. Conversely, the more complex the tortuosity of the escape hole 22, the more difficult it is for particles to escape, and the less electron dose escaped per unit time.

[0102] Thus, at the first end 23, a greater number of electrons are drawn out of the plasma chamber 21. To compensate for the greater number of electrons drawn out at the first end 23, the gas near the first end 23 is ionized more, resulting in a relatively low gas concentration. Near the middle of the plasma chamber 21 and near the second end 24, the leakage efficiency of gas molecules / atoms decreases, causing the gas concentration near the middle of the plasma chamber 21 and near the second end 24 to increase. This can compensate for the deficiency that the low power near the middle of the plasma chamber 21 and near the second end 24 prevents the formation of an electron cyclotron resonance region, thus enabling the formation of an ECR region near the middle of the plasma chamber 21 and near the second end 24.

[0103] It is understood that the number of escaping holes 22 in the microwave electron gun provided in Embodiment 4 can be, for example, three, five or more, and the embodiments of the present invention do not limit this.

[0104] It is understood that the above four embodiments are only one way to reduce the particle escape efficiency of the escape region A. In practical applications, if a better effect is desired, the above four embodiments can be superimposed.

[0105] For example: In Embodiment 1 superimposed with Embodiment 2, from the first end 23 to the second end 24, the area of ​​each escaping hole 22 gradually decreases, while the number of sub-escaping holes included in each escaping hole 22 gradually decreases.

[0106] In Example 1 superimposed with Example 3, from the first end 23 to the second end 24, the area of ​​each outlet hole 22 gradually decreases while the length of the outlet hole 22 gradually increases.

[0107] In Example 1 superimposed with Example 4, from the first end 23 to the second end 24, the area of ​​each escaping hole 22 gradually decreases while the tortuosity of the escaping hole 22 gradually increases.

[0108] In Example 2 superimposed with Example 3, from the first end 23 to the second end 24, the number of sub-escape holes included in each escape hole 22 gradually decreases while the length of the escape hole 22 gradually increases.

[0109] In Example 2 superimposed on Example 4, from the first end 23 to the second end 24, the number of sub-escape holes included in each escape hole 22 gradually decreases while the tortuosity of the escape hole 22 gradually increases.

[0110] In Example 3 superimposed with Example 4, from the first end 23 to the second end 24, the length of the outlet hole 22 gradually increases, while the tortuosity of the outlet hole 22 gradually increases.

[0111] For example, in Embodiment 1 superimposed with Embodiment 2, and in Embodiment 3, from the first end 23 to the second end 24, the area of ​​each escaping hole 22 gradually decreases, while the number of sub-escaping holes included in each escaping hole 22 gradually decreases, and the length of the escaping hole 22 gradually increases.

[0112] In Embodiment 1, Embodiment 2, and Embodiment 4 are superimposed. From the first end 23 to the second end 24, the area of ​​each escaping hole 22 gradually decreases, while the number of sub-escaping holes included in each escaping hole 22 gradually decreases, and the tortuosity of the escaping hole 22 gradually increases.

[0113] In Example 1, Example 3, and Example 4 are superimposed. From the first end 23 to the second end 24, the area of ​​each escaping hole 22 gradually decreases while the length of each escaping hole 22 gradually increases, and the tortuosity of each escaping hole 22 gradually increases.

[0114] In Embodiment 2, Embodiment 3, and Embodiment 4, from the first end 23 to the second end 24, the number of sub-escape holes included in each escape hole 22 gradually decreases while the length of each escape hole 22 gradually increases, and the tortuosity of each escape hole 22 gradually increases.

[0115] For example, in Embodiment 1, Embodiment 2, Embodiment 3, and Embodiment 4, from the first end 23 to the second end 24, the area of ​​each escaping hole 22 gradually decreases, while the number of sub-escaping holes included in each escaping hole 22 gradually decreases, the length of each escaping hole 22 gradually increases, and the tortuosity of each escaping hole 22 gradually increases.

[0116] Example 5

[0117] The cross-sectional area of ​​the vent 22 gradually increases from the side closer to the plasma chamber 21 to the side farther away from the plasma chamber 21.

[0118] The cross-sectional area of ​​the vent 22 can also be such that it gradually decreases from the side closest to the plasma chamber 21 to the side furthest from the plasma chamber 21.

[0119] Please refer to Figure 9 , Figure 9 This is a schematic diagram of the structure of a microwave electron gun provided in an embodiment of the present invention.

[0120] Figure 9 The diagram shows a structure in which the cross-sectional area of ​​the effluent port 22 gradually increases from the side closest to the plasma chamber 21 to the side furthest from the plasma chamber 21. Figure 9As shown, the effluent aperture 22 can be funnel-shaped. The electric field generated by the ion beam B can enter the funnel-shaped effluent aperture 22, which is used to extract electrons from the plasma chamber 21. From the first end 23 to the second end 24, the cross-sectional area (maximum cross-sectional area) of the side of the funnel-shaped effluent aperture 22 away from the plasma chamber 21 gradually decreases, and the depth of the funnel-shaped effluent aperture 22 becomes shallower. The closer to the first end 23, the deeper the electric field penetrates the effluent aperture 22, and the greater the electron dose extracted per unit time. The closer to the second end 24, the shallower the electric field penetrates the effluent aperture 22, and the less electron dose extracted per unit time.

[0121] Example 6

[0122] Please refer to Figure 4 and Figures 6-8 The cross-sectional area of ​​the vent 22 remains constant from the side closest to the plasma chamber 21 to the side furthest from the plasma chamber 21.

[0123] Examples 5 and 6 define the change in the cross-sectional area of ​​the escaping hole 22 from the side closest to the plasma chamber 21 to the side furthest from the plasma chamber 21. The cross-sectional area of ​​the escaping hole 22 can remain constant, for example, the escaping hole 22 is a cylindrical hole; the cross-sectional area of ​​the escaping hole 22 can also gradually increase or gradually decrease, for example, a conical hole (gradually increasing from the side closest to the plasma chamber 21 to the side furthest from the plasma chamber 21), or an inverse conical hole (gradually decreasing from the side closest to the plasma chamber 21 to the side furthest from the plasma chamber 21).

[0124] Based on the combination of Embodiments 5 and 6 with Embodiments 1, 2, 3 and 4, Embodiments 7, 8, 9, 10 and 11 can be derived to illustrate the arrangement of cylindrical holes, conical holes and reverse conical holes on the sidewall of plasma chamber 21.

[0125] Example 7

[0126] Example 5 can be superimposed on Example 1. The cross-sectional area of ​​the escaping hole 22 gradually increases from the side closer to the plasma chamber 21 to the side farther away from the plasma chamber 21. In this case, from the first end 23 to the second end 24, the area of ​​each escaping hole 22 gradually decreases. For example, the cross-sectional area (minimum cross-sectional area) of the escaping hole 22 closer to the plasma chamber 21 remains unchanged, while the cross-sectional area (maximum cross-sectional area) of the escaping hole 22 farther away from the plasma chamber 21 gradually decreases, that is, the electric field penetrates the escaping hole 22 shallower and shallower.

[0127] Example 8

[0128] Example 5 can be superimposed on Example 2. The cross-sectional area of ​​the escaping hole 22 gradually increases from the side closer to the plasma chamber 21 to the side farther away from the plasma chamber 21. In this case, from the first end 23 to the second end 24, the number of sub-escaping holes included in each escaping hole 22 gradually decreases. For example, from the first end 23 to the second end 24, the cross-sectional area of ​​the sub-escaping holes included in each escaping hole 22 gradually increases from the side closer to the plasma chamber 21 to the side farther away from the plasma chamber 21, and the number of sub-escaping holes gradually decreases.

[0129] Example 9

[0130] Example 5 can be superimposed on Example 4. The cross-sectional area of ​​the escaping hole 22 gradually increases from the side closer to the plasma chamber 21 to the side farther away from the plasma chamber 21. In this case, from the first end 23 to the second end 24, the tortuosity of each escaping hole 22 becomes more and more complex. For example, from the first end 23 to the second end 24, the cross-sectional area of ​​the escaping hole 22 gradually increases from the side closer to the plasma chamber 21 to the side farther away from the plasma chamber 21, and the tortuosity of each escaping hole 22 gradually increases.

[0131] Example 10

[0132] In the superposition of Embodiments 1, 4, and 5, the cross-sectional area of ​​the escaping hole 22 gradually increases from the side closer to the plasma chamber 21 to the side farther away from the plasma chamber 21. In this case, from the first end 23 to the second end 24, the cross-sectional area of ​​each escaping hole 22 gradually decreases, and the tortuosity of the escaping hole 22 becomes more and more complex. For example, from the first end 23 to the second end 24, the cross-sectional area (minimum cross-sectional area) of the escaping hole 22 on the side closer to the plasma chamber 21 remains unchanged, while the cross-sectional area (maximum cross-sectional area) of the escaping hole 22 on the side farther away from the plasma chamber 21 gradually decreases, and the tortuosity of the escaping hole 22 gradually increases.

[0133] Example 11

[0134] In the superposition of Embodiments 2, 4, and 5, the cross-sectional area of ​​the escaping hole 22 gradually increases from the side closer to the plasma chamber 21 to the side farther away from the plasma chamber 21. In this case, from the first end 23 to the second end 24, the number of sub-escaping holes included in each escaping hole 22 gradually decreases. For example, from the first end 23 to the second end 24, the cross-sectional area of ​​the sub-escaping holes included in each escaping hole 22 gradually increases from the side closer to the plasma chamber 21 to the side farther away from the plasma chamber 21, the number of sub-escaping holes gradually decreases, and the tortuosity of the sub-escaping holes gradually increases.

[0135] Additionally, the conical orifice and the reverse conical orifice mentioned in Embodiment Six can also appear simultaneously on the sidewall of the plasma chamber 21, for example:

[0136] The cross-sectional area of ​​the escape aperture 22 in the escape region A of the microwave electron gun can also be, for example:

[0137] From the first end 23 to the middle of the plasma chamber 21, the cross-sectional area of ​​the escaping hole 22 gradually increases from the side closer to the plasma chamber 21 to the side farther away from the plasma chamber 21.

[0138] From the middle of the plasma chamber 21 to the second end 24, the cross-sectional area of ​​the vent hole 22 gradually decreases from the side closer to the plasma chamber 21 to the side farther away from the plasma chamber 21.

[0139] In conjunction with Embodiment 1, from the first end 23 to the middle of the plasma chamber 21, the cross-sectional area of ​​each escaping hole 22 on the side close to the plasma chamber 21 remains unchanged, while the cross-sectional area on the side away from the plasma chamber 21 gradually decreases.

[0140] From the middle of the plasma chamber 21 to the second end 24, the cross-sectional area of ​​each vent 22 on the side away from the plasma chamber 21 remains unchanged, while the cross-sectional area on the side closer to the plasma chamber 21 gradually decreases.

[0141] Of course, in the embodiments of the present invention, the cross-sectional area of ​​the escaping hole 22 may also have other implementations obtained in combination with embodiments one to six, which will not be listed here.

[0142] In one embodiment, the aforementioned microwave electron gun may further include, for example, a microwave generator and a gas supply device;

[0143] The microwave generator is connected to the first terminal 23 and is used to generate microwaves and input microwaves to the first terminal 23.

[0144] The gas supply device is connected to the second end 24 and is used to store and input gas to the second end 24.

[0145] In addition, the microwave electron gun provided in the embodiments of the present invention may also include, for example, a waveguide assembly, a conductive rod, and a dielectric tube.

[0146] The microwave generator is connected to the waveguide assembly, which transmits the microwaves generated by the microwave generator to the conductive rod. The conductive rod is inserted into the plasma chamber 21 from the first end 23 to receive the microwaves transmitted by the waveguide assembly and transmit microwaves into the plasma chamber 21. The dielectric tube is wrapped around the outside of the conductive rod to provide support and positioning for the conductive rod.

[0147] Based on the same inventive concept, embodiments of the present invention also provide a method for generating an electron cyclotron resonance region, applicable to the microwave electron gun described in any of the foregoing embodiments. Please refer to... Figure 10 , Figure 10 This is a flowchart illustrating a method for generating an electron cyclotron resonance region as improved in an embodiment of the present invention.

[0148] like Figure 10 As shown, the method for generating the electron cyclotron resonance region includes the following steps:

[0149] Step S110: Microwaves are introduced from the first end of the plasma chamber of the microwave electron gun, and gas is introduced from the second end of the plasma chamber of the microwave electron gun; the microwave power gradually decreases from the first end to the second end, and the gas concentration gradually increases from the first end to the second end.

[0150] In step S120, the microwave power and gas concentration are complementary, so that the plasma generated by the interaction of microwave power and gas concentration at each position of the plasma chamber from the first end to the second end is balanced, forming a uniformly distributed electron cyclotron resonance region.

[0151] As can be seen, the method for generating an electron cyclotron resonance region provided in this embodiment of the invention utilizes the aforementioned microwave electron gun structure. It only requires introducing microwaves from the first end and gas from the second end. Since the particle escape efficiency of the aforementioned microwave electron gun decreases from the first end to the second end, the gas concentration can gradually increase from the first end to the second end. Through the complementarity of gas concentration and microwave power, the plasma generated by the interaction of microwave power and gas concentration at various locations in the plasma chamber from the first end to the second end is balanced. This compensates for the defect that the electron cyclotron resonance region cannot be formed near the second end due to the gradual decrease in microwave power from the first end to the second end. This overcomes the problem in related technologies where a uniformly distributed electron cyclotron resonance region cannot be formed in the original plasma chamber of the microwave electron gun. After forming a uniformly distributed electron cyclotron resonance region, more electrons can escape from the microwave electron gun, thereby meeting the electron quantity required for subsequent ion beam charge neutralization and improving the accuracy of ion implantation.

[0152] Based on the same inventive concept, embodiments of the present invention also provide an ion implanter that uses the microwave electron gun described in any of the foregoing embodiments.

[0153] 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 invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A microwave electron gun, characterized in that, include: A plasma chamber; the plasma chamber has a first end and a second end; the first end is used to introduce microwaves; the second end is used to introduce gas. The plasma chamber has an escape region on its side wall. From the first end to the second end, the particle escape efficiency of the escape region gradually decreases. The particles include electrons and / or gas molecules / atoms. The microwave electron gun also includes: a microwave generator and a gas supply device; The microwave generator is connected to the first end and is used to generate microwaves and input microwaves to the first end. The gas supply device is connected to the second end and is used to store gas and input gas to the second end. The microwave power and gas concentration are complementary, so that the plasma generated by the interaction of microwave power and gas concentration is balanced at each position of the plasma chamber from the first end to the second end, forming a uniformly distributed electron cyclotron resonance region.

2. The microwave electron gun as described in claim 1, characterized in that, The gradual decrease in particle escape efficiency from the first end to the second end includes: The escape region is provided with multiple escape holes, and the area of ​​each escape hole gradually decreases from the first end to the second end.

3. The microwave electron gun as described in claim 1, characterized in that, The gradual decrease in particle escape efficiency from the first end to the second end includes: The escape region is provided with multiple escape holes, each escape hole including a different number of sub-escape holes, and from the first end to the second end, the number of sub-escape holes included in each escape hole gradually decreases.

4. The microwave electron gun as described in claim 1, characterized in that, The gradual decrease in particle escape efficiency from the first end to the second end includes: The escape area is provided with multiple escape holes, and the length of each escape hole gradually increases from the first end to the second end.

5. The microwave electron gun as described in claim 1, characterized in that, The gradual decrease in particle escape efficiency from the first end to the second end includes: The escape area is provided with multiple escape holes, and the tortuosity of each escape hole gradually increases from the first end to the second end.

6. The microwave electron gun according to any one of claims 2-5, characterized in that, The cross-sectional area of ​​the vent hole gradually increases from the side closest to the plasma chamber to the side furthest from the plasma chamber.

7. The microwave electron gun as described in any one of claims 2-5, characterized in that, From the first end to the middle of the plasma chamber, the cross-sectional area of ​​the effluent gradually increases from the side closer to the plasma chamber to the side farther away from the plasma chamber. From the middle of the plasma chamber to the second end, the cross-sectional area of ​​the effluent gradually decreases from the side closer to the plasma chamber to the side farther away from the plasma chamber.

8. A method for generating an electron cyclotron resonance region, applied to the microwave electron gun according to any one of claims 1-7, characterized in that, include: Microwaves are introduced from the first end of the plasma chamber of the microwave electron gun, and gas is introduced from the second end of the plasma chamber of the microwave electron gun; the microwave power gradually decreases from the first end to the second end, and the gas concentration gradually increases from the first end to the second end. The microwave power and gas concentration are complementary, so that the plasma generated by the interaction of microwave power and gas concentration is balanced at each position of the plasma chamber from the first end to the second end, forming a uniformly distributed electron cyclotron resonance region.

9. An ion implanter, characterized in that, The microwave electron gun as described in any one of claims 1-7 is used.

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