Long-life pollution ion source device

Abstract

The invention relates to the technical field of semiconductor ion implantation processing devices, and discloses a long-life pollution ion source device which comprises a cavity, a round hole is formed in one end in the cavity, a cathode penetrates through the round hole and extends into the cavity, the cathode is cylindrical, a lamp filament is arranged in the cathode, a fixing ring is arranged on the outer side of the cathode, and the fixing ring is fixed to one end of the inner wall of the cavity. An air inlet is formed in the side face of the cavity, the cavity and the cathode are connected with an arc cavity power source and a cathode power source respectively, the cathode does not make contact with the cavity, the lamp filament is connected with a lamp filament power source, and a variable magnetic field module capable of changing the direction and intensity of a magnetic field in the cavity is arranged on the fixing ring and can influence the movement track of electrons. And the electrons advance along a spiral path, so that the advancing path of the electrons is increased, the electrons have more collision with gas atoms, and the ionization efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor ion implantation processing equipment technology, specifically a long-life contamination ion source device. Background Technology

[0002] In semiconductor front-end manufacturing, ion implantation is an indispensable and crucial process. Its main purpose is to implant impurity atoms into desired locations on a silicon wafer, creating a conductive layer. The choice of ion source is critical to the ion implantation process. Commonly used ion sources include gas sources, solid sources, and liquid sources. When selecting an ion source, factors such as stability, purity, ease of operation, and suitability for the target substrate should be considered. An ion source is a device that ionizes neutral atoms or molecules and extracts an ion beam. Its primary function is to convert neutral atoms or molecules into charged particles, i.e., ions. This process can be achieved through various mechanisms, such as gas discharge, electron beam collisions with gas atoms or molecules, sputtering of the working material by a charged particle beam, and surface ionization. These ions are then extracted and form a beam for various scientific and engineering applications, such as materials characterization, surface treatment, and ion implantation.

[0003] The arc chamber life of an ion source is affected by a variety of factors, including the type of ion source, the operating environment, and maintenance conditions. In semiconductor device manufacturing, the ion source is a key component of the ion implanter, and the arc chamber life directly affects the production efficiency and reliability of the ion implanter.

[0004] Traditional hot filament ion sources, such as the Fluorimann and Benas ion sources, suffer from high-temperature sputtering, corrosive gas erosion, and ion radiation, resulting in a large amount of gaseous byproducts adhering to the arc chamber surface, leading to a short service life. Furthermore, the low binding rate between electrons generated by the filament and the ionized gas directly affects the production efficiency and reliability of the ion implanter.

[0005] Therefore, to improve the arc chamber life of ion sources, a series of measures are needed, such as improving the structural design of the ion source, using more durable materials, optimizing the operating environment, and strengthening maintenance. At the same time, new ion source technologies, such as ion sources with long-life cathodes, can also be considered to extend the arc chamber life and improve the overall performance of the ion implanter. Summary of the Invention

[0006] (a) Technical problem to be solved: In view of the shortcomings of the prior art, the present invention provides a long-life pollution ion source device, which can improve the gas ionization rate and solve the problem of short arc chamber life.

[0007] (II) Technical Solution: To achieve the above-mentioned goals of improving arc chamber life and gas ionization rate, the present invention provides the following technical solution: a long-life pollution ion source device, comprising a chamber, wherein a circular hole is provided at one end of the chamber, a cathode extends into the chamber through the circular hole, the cathode is cylindrical, a filament is provided inside, and a fixing ring is provided on the outside, the fixing ring is fixed to one end of the inner wall of the chamber, an air inlet is provided on one side of the chamber, and an arc-shaped slit for leading out the ion source is provided on one side of the chamber, the chamber and the cathode are respectively connected to the arc chamber power supply and the cathode power supply, and the cathode and the chamber are not in contact, the filament is connected to the filament power supply, and a variable magnetic field module capable of changing the direction and intensity of the magnetic field in the chamber is provided around the filament.

[0008] Preferably, the variable magnetic field module is a pair of permanent magnet strips placed on both sides of the filament that attract each other. The permanent magnet strips extend along the direction in which electrons are emitted from the filament, and the magnetic field direction changes in the direction of extension of the mutually attracting permanent magnet strips.

[0009] Preferably, the permanent magnet strip is composed of small magnets arranged in clockwise and counterclockwise directions, respectively, arranged closely together.

[0010] Preferably, the variable magnetic field module is specifically an electromagnet, which is arranged in a circular array on a fixed ring and is independently controlled. The power supply and current of each electromagnet can be controlled separately, and the electromagnet is connected to a power source.

[0011] Preferably, the variable magnetic field module consists of permanent magnets and electromagnets. Electromagnets are arranged in a circular array on the outer side of the fixed ring and connected to the electromagnet power supply. They are independently controllable, and the on / off state of each electromagnet and the magnitude of the current passing through it can be controlled separately. An insulating material is provided between the electromagnets and the chamber. A circular guide rail is provided on the fixed ring, and two permanent magnets with opposite polarities are rotatably arranged relative to each other on the guide rail.

[0012] Preferably, an insulating damping layer is provided between the cathode and the chamber to fill the gap between them, preventing gas from flowing out of the chamber.

[0013] Preferably, a repellent is provided at the end of the chamber furthest from the cathode. The main function of the repellent is to limit the area where the filament emits electrons. Since the arc chamber is usually made of metal, when ions and electrons in the plasma collide with the surface of the chamber, high temperature and high energy are generated, which leads to damage to the surface material of the chamber and the adhesion of dirt. The repellent can repel the electrons emitted by the filament through the electric field and limit the electrons in the area of ​​ionized gas. The presence of the repellent can effectively reduce this disadvantage.

[0014] Preferably, the filament head is cylindrical or annular. The shape of the hot filament does affect the voltage acceleration effect, and thus the impact effect of the thermally ionized electrons. The principle of voltage acceleration is to use an electric field to apply a force to charged particles, so that the particles gain kinetic energy and accelerate them. Therefore, the effect of voltage acceleration depends on the electric field strength and direction. In order to achieve efficient voltage acceleration, it is necessary to ensure that the electric field strength is uniformly distributed on the surface of the hot filament and is perpendicular to the direction of electron movement. The shape of the hot filament will affect the electric field distribution on its surface. If the shape of the hot filament is cylindrical, then the electric field near its surface will be radially distributed. In order to accelerate the electrons along the axial direction, the hot filament needs to be designed as a cylinder with an appropriate length so that the electrons can gain sufficient kinetic energy before colliding with the special gas.

[0015] Preferably, the chamber, cathode, fixing ring, and deflector housing are made of tungsten. Tungsten has a high melting point of 3410 degrees Celsius, allowing it to remain stable and resistant to deformation or calcination at high temperatures. This makes tungsten a suitable material for manufacturing parts in ion implantation arc chambers that need to withstand high temperatures and ion impacts. Tungsten has good electrical conductivity and corrosion resistance, which helps reduce the heat generated during ion implantation and minimize corrosion of the material. Its high density and low coefficient of thermal expansion help improve the thermal stability and mechanical strength of the arc chamber, thus ensuring the stability and accuracy of the ion implantation process. Tungsten also possesses excellent mechanical and processing properties; its high hardness allows it to withstand the impacts and stresses generated during ion implantation. Furthermore, tungsten has good processing properties, allowing for easy cutting, drilling, and other machining operations. It does not contain substances harmful to humans or the environment, meeting environmental protection requirements. In addition, tungsten is a low-toxicity material, ensuring high safety during use.

[0016] (III) Beneficial Effects: Compared with the prior art, the present invention provides a long-life pollution ion source device, which has the following beneficial effects: 1. The gas to be ionized is introduced through the inlet. A negative charge is applied to the chamber and cathode, with a filament inside the cathode. The filament is energized, heating it to excite electrons. Due to the electrification of the chamber and cathode, the electrons emitted by the filament collide with the gas under the electric field of the cathode, forming plasma. The heating of the filament releases thermionic electrons from its surface. These thermionic electrons are accelerated by the repulsion of electrons from the cathode, further accelerating gas ionization. A variable magnetic field module creates a variable magnetic field within the chamber through which the excited electrons pass. This variable magnetic field can apply an additional Lorentz force to the generated ions. This design facilitates more precise control over the trajectory and speed of ions. Simultaneously, the energization of the chamber and cathode creates an electric field that promotes ion movement within the chamber. Furthermore, the cylindrical or annular shape of the filament allows for better axial helical motion, enabling more electrons to collide with gas atoms. This reduces the required temperature or current for filament thermal ionization, decreasing energy consumption and enabling more efficient ion source production. The electrons released by the filament are more easily controlled; the magnetic field influences their trajectory, guiding them along a helical path, increasing their travel distance and maximizing collisions with gas atoms, thus improving ionization efficiency.

[0017] 2. The permanent magnet strip is composed of small magnets arranged in clockwise and counterclockwise directions, respectively, closely arranged. In the figure, the elliptical area is the S-pole magnetic reinforcement area, the square is the N-pole magnetic reinforcement area, the magnetic field lines are emitted from the N-pole to the S-pole, the arrows are the direction of electron movement, the solid dots are the direction of force on the electrons pointing towards the face, and X is the direction of force on the electrons away from the face. This causes the electrons emitted by the filament to be pulled by the magnetic field repeatedly, so that the electrons follow an S-shaped path, which prolongs the path of the electrons in the cavity, allowing more electrons to ionize the gas better, reducing energy consumption and reducing the bombardment loss of electrons inside the cavity. At the same time, this arrangement strengthens the magnetic field and is suitable for the length of the permanent magnet strip.

[0018] 3. A fixed ring is provided on the outer ring of the cathode, and an array of electromagnets is provided on the fixed ring. Each electromagnet is independently controlled. By controlling the on / off state of each electromagnet and the magnitude of its voltage and current, and by connecting the electromagnets to the control mode of a brushless motor, the permanent magnet is driven. The permanent magnet provides the electrons emitted by the filament with a continuously rotating magnetic field, so that a variable magnetic field that changes continuously clockwise or counterclockwise is formed in the cavity. The magnetic field can affect the trajectory of the electrons, causing them to travel along a spiral path, increasing the distance the electrons travel and the space they pass through, increasing the time the electrons stay in the cavity, improving the ionization efficiency of the electrons, reducing energy consumption, reducing the electron bombardment of the cavity, and increasing the service life of the cavity. Attached Figure Description

[0019] Figure 1This is a schematic diagram of the structure of Embodiment 1 of the present invention; Figure 2 This is a cross-sectional view of Embodiment 1 of the present invention; Figure 3 This is a circuit connection diagram of Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the operation of the variable magnetic field module according to Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the filament of the present invention; Figure 6 This is a schematic diagram of electron collisions in this invention; Figure 7 This is a schematic diagram of the structure of Embodiment 2 of the present invention; Figure 8 This is a cross-sectional structural diagram of Embodiment 2 of the present invention; Figure 9 This is a schematic diagram of the arrangement structure of the permanent magnet strips in Embodiment 2 of the present invention; Figure 10 This is a schematic diagram of the structure of Embodiment 3 of the present invention; Figure 11 Cross-sectional view of embodiment three of the present invention; Figure 12 This is a circuit connection diagram of Embodiment 3 of the present invention.

[0020] In the diagram: 1. Chamber; 3. Alternator; 4. Arc-shaped slit; 11. Air inlet; 13. Insulating damping layer; 21. Cathode; 22. Permanent magnet; 23. Fixing ring; 230. Permanent magnet strip; 231. Electromagnet; 211. Filament. Detailed Implementation

[0021] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1: Please refer to Figure 1-3 , Figure 5This long-life pollution ion source device has a circular hole at one end of the chamber 1. The cathode 21 extends into the chamber 1 through the circular hole. The cathode 21 is cylindrical and has a filament 211 inside and a fixing ring 23 on the outside. The fixing ring 23 is fixed to one end of the inner wall of the chamber 1. The chamber 1 has an air inlet 11 on one side and an arc-shaped slit 4 for leading out the ion source on one side. The chamber 1 and the cathode 21 are connected to the arc cavity power supply and the cathode power supply, respectively, and the cathode 21 is not in contact with the chamber 1. The filament 211 is connected to the filament power supply. A variable magnetic field module that can change the direction and intensity of the magnetic field in the chamber 1 is provided around the filament 211.

[0023] The variable magnetic field module is specifically an electromagnet 231, which is arranged in a circular array on the fixed ring 23 and is independently controllable. The energization and current flow direction and magnitude of each electromagnet 231 can be controlled separately. (See reference...) Figure 4 By switching the electromagnets on and off, the corresponding electromagnets can be controlled to rotate clockwise or counterclockwise and change the magnetic field. When the electromagnet power supply is connected, by controlling the on / off state of each electromagnet 231 and the magnitude of the voltage and current, a clockwise or counterclockwise changing magnetic field is formed around the filament 211. The emitted electrons are affected by the changing magnetic field. After the electrons leave the filament 211, they spiral away from the filament 211. As the electrons move away, the magnetic field weakens, the Lorentz force on the electrons becomes smaller and smaller, the radius of motion becomes larger and larger, and the relative path of the electrons becomes longer, which is more conducive to the collision of electrons with gas atoms and the excitation of ionized gas.

[0024] The gas to be ionized is introduced through inlet 11. A negative charge is applied to chamber 1 and cathode 21. A filament 211 is installed inside cathode 21. The energized filament 211 heats up and excites electrons. Due to the energization of chamber 1 and cathode 21, the electrons emitted by the filament collide with the gas under the electric field of the cathode, forming plasma. The heating of filament 211 releases thermionic electrons from its surface. These thermionic electrons are accelerated by the electron repulsion of the cathode, colliding with the gas and accelerating its ionization. (See reference...) Figure 6Through the variable magnetic field module, a variable magnetic field is formed in chamber 1 to excite electrons to pass through. The variable magnetic field can apply an additional Lorentz force to the generated ions, which helps to more accurately control the trajectory and speed of the ions. At the same time, the energization of chamber 1 and cathode 21 forms an electric field, which can promote the movement of ions in the chamber. Furthermore, the cylindrical or annular shape of filament 211 can better form an axial helical motion, so that more electrons collide with gas atoms, thereby reducing the temperature or current required for the thermal ionization of filament 211, reducing energy consumption, and enabling more efficient ion source production. The electrons released by filament 211 can be more easily controlled. The magnetic field can affect the trajectory of electrons, causing them to travel along a helical path, increasing the collision of thermally ionized electrons with gas atoms, and improving ionization efficiency.

[0025] The chamber 1 is equipped with a repellent 3 at the end away from the cathode 21. The main function of the repellent 3 is to limit the area where the filament 3 emits electrons. Since the arc chamber is usually made of metal, when ions and electrons in the plasma collide with the surface of the chamber, high temperature and high energy are generated, which leads to damage to the surface material of the chamber and the adhesion of dirt. The repellent can repel the electrons emitted by the filament 3 through the electric field and limit the electrons in the area of ​​ionized gas. The presence of the repellent can effectively reduce this disadvantage.

[0026] The head of the filament 211 is cylindrical or annular. The shape of the hot filament 211 does affect the effect of electron ejection from the filament 3. The ejection principle is to use an electric field to apply a force to charged particles, giving the particles kinetic energy. Therefore, the effect of electron ejection depends on the electric field strength and direction. In order to achieve efficient ejection acceleration, it is necessary to ensure that the electric field strength is uniformly distributed on the surface of the hot filament 211 and parallel to the direction of electron movement. The shape of the hot filament affects the electric field distribution on its surface. If the hot filament 211 is cylindrical, the electric field near its surface will be radially distributed. In order to accelerate electrons axially, the hot filament 211 needs to be designed as a cylinder with an appropriate length so that electrons can be smoothly ejected from the filament 3. The chamber 1, cathode 21, fixing ring 23, and the outer shell of the deflector 3 are made of tungsten. Tungsten has a high melting point of 3410°C, which allows it to remain stable and resistant to deformation or calcination at high temperatures. This makes tungsten a suitable material for manufacturing parts in the ion implantation arc chamber that need to withstand high temperatures and ion impacts. Tungsten has good electrical conductivity and corrosion resistance, which helps reduce the heat generated during ion implantation and reduce corrosion of the material. Tungsten has a high density and a low coefficient of thermal expansion, which helps improve the thermal stability and mechanical strength of the arc chamber, thereby ensuring the stability and accuracy of the ion implantation process. It also has excellent mechanical and processing properties. Tungsten has high hardness and excellent mechanical properties, which can withstand the impact and stress generated during ion implantation. At the same time, tungsten has good processing properties and can be easily machined by cutting, drilling, and other mechanical processes. It does not contain substances harmful to the human body and the environment, meeting environmental protection requirements. In addition, tungsten is also a low-toxicity material with high safety during use.

[0027] Working Principle: This device uses a gas source as an ion source for semiconductor ion implantation. The gas to be ionized is introduced through inlet 11. The chamber 1 and cathode 21 are energized. A filament 211 is located inside the cathode 21. The filament 211 heats up when energized, generating electrons. The cathode 21 ejects high-energy electrons, causing gas atoms in the chamber to collide and lose electrons, forming gas ions. (See reference...) Figure 5 A fixed ring 23 is provided on the outer ring of the cathode 21. An array of electromagnets 231 is provided on the fixed ring 23. Each electromagnet 231 is independently controlled. By controlling the on and off of each electromagnet 231 and the magnitude of its voltage and current, a variable magnetic field that changes clockwise or counterclockwise is formed in the chamber 1. The magnetic field can affect the trajectory of electrons, causing them to travel along a spiral path, increasing the distance electrons travel and the space they pass through, increasing the time electrons stay in the chamber 1, improving electron ionization efficiency, reducing energy consumption, reducing the number of electrons bombarding the chamber 1, and increasing the service life of the chamber 1.

[0028] Example 2: Please refer to Figure 7-8This long-life pollution ion source device has a circular hole at one end of the chamber 1. The cathode 21 extends into the chamber 1 through the circular hole. The cathode 21 is cylindrical and has a filament 211 inside. A fixing ring 23 is provided on the outside and fixed to one end of the inner wall of the chamber 1. An air inlet 11 is provided on one side of the chamber 1. An arc-shaped slit 4 for leading out the ion source is provided on one side of the chamber 1. An insulating damping layer 13 is provided between the cathode 21 and the chamber 1 to fill the gap and prevent gas in the chamber 1 from flowing out. The chamber 1 and the cathode 21 are connected to the arc cavity power supply and the cathode power supply, respectively, and the cathode 21 is not in contact with the chamber 1. The filament 211 is connected to the filament power supply. A variable magnetic field module that can change the direction and intensity of the magnetic field in the chamber 1 is provided around the filament 211.

[0029] The gas to be ionized is introduced through inlet 11. A negative charge is applied to chamber 1 and cathode 21. A filament 211 is installed inside cathode 21. The energized filament 211 heats up and excites electrons. Due to the energization of chamber 1 and cathode 21, the electrons emitted by the filament collide with the gas under the electric field of the cathode, forming plasma. The heating of filament 211 releases thermionic electrons from its surface. These thermionic electrons are accelerated by the electron repulsion of the cathode, colliding with the gas and accelerating its ionization. (See reference...) Figure 6 Through the variable magnetic field module, a variable magnetic field is formed in chamber 1 to excite electrons to pass through. The variable magnetic field can apply an additional Lorentz force to the generated ions, which helps to more accurately control the trajectory and speed of the ions. At the same time, the energization of chamber 1 and cathode 21 forms an electric field, which can promote the movement of ions in the chamber. Furthermore, the cylindrical or annular shape of filament 211 can better form an axial helical motion, so that more electrons collide with gas atoms, thereby reducing the temperature or current required for the thermal ionization of filament 211, reducing energy consumption, and enabling more efficient ion source production. The electrons released by filament 211 can be more easily controlled. The magnetic field can affect the trajectory of electrons, causing them to travel along a helical path, increasing the collision of thermally ionized electrons with gas atoms, and improving ionization efficiency.

[0030] The variable magnetic field module is specifically a permanent magnet strip 230 placed on both sides of the filament 211 and attracting each other. The permanent magnet strip 230 extends along the direction of electron emission from the filament, and the mutual attraction of the permanent magnet strip 230 changes the direction of the magnetic field in the extending direction.

[0031] See Figure 9The permanent magnet strip 230 is composed of closely arranged small magnets rotating clockwise and counterclockwise according to their polarity. In the figure, the elliptical area represents the S-pole magnetic reinforcement area, the box represents the N-pole magnetic reinforcement area, magnetic field lines radiate from the N-pole to the S-pole, the arrows indicate the direction of electron movement, the solid dots represent the direction of force on the electrons pointing towards the face, and X represents the direction of force on the electrons away from the face. This causes the electrons emitted by the filament 3 to be repeatedly pulled by the magnetic field, resulting in an S-shaped path for the electrons. This extends the electrons' path within the chamber 1, allowing more electrons to ionize the gas more effectively, reducing energy consumption and minimizing bombardment losses within the chamber 1. Simultaneously, this arrangement strengthens the magnetic field while adapting to the length of the permanent magnet strip 230.

[0032] Example 3: Please refer to Figure 10-12 This long-life pollution ion source device has a circular hole at one end of the chamber 1. The cathode 21 extends into the chamber 1 through the circular hole. The cathode 21 is cylindrical and has a filament 211 inside. A fixing ring 23 is provided on the outside and fixed to one end of the inner wall of the chamber 1. An air inlet 11 is provided on one side of the chamber 1. An arc-shaped slit 4 for leading out the ion source is provided on one side of the chamber 1. An insulating damping layer 13 is provided between the cathode 21 and the chamber 1 to fill the gap and prevent gas in the chamber 1 from flowing out. The chamber 1 and the cathode 21 are connected to the arc cavity power supply and the cathode power supply, respectively, and the cathode 21 is not in contact with the chamber 1. The filament 211 is connected to the filament power supply. A variable magnetic field module that can change the direction and intensity of the magnetic field in the chamber 1 is provided around the filament 211.

[0033] The chamber 1 is equipped with a repellent 3 at the end away from the cathode 21. The main function of the repellent 3 is to limit the area where the filament 3 emits electrons. Since the arc chamber is usually made of metal, when ions and electrons in the plasma collide with the surface of the chamber, high temperature and high energy are generated, which leads to damage to the surface material of the chamber and the adhesion of dirt. The repellent can repel the electrons emitted by the filament 3 through the electric field and limit the electrons in the area of ​​ionized gas. The presence of the repellent can effectively reduce this disadvantage.

[0034] The gas to be ionized is introduced through inlet 11. A negative charge is applied to chamber 1 and cathode 21. A filament 211 is installed inside cathode 21. The energized filament 211 heats up and excites electrons. Due to the energization of chamber 1 and cathode 21, the electrons emitted by the filament collide with the gas under the electric field of the cathode, forming plasma. The heating of filament 211 releases thermionic electrons from its surface. These thermionic electrons are accelerated by the electron repulsion of the cathode, colliding with the gas and accelerating its ionization. (See reference...) Figure 6Through the variable magnetic field module, a variable magnetic field is formed in chamber 1 to excite electrons to pass through. The variable magnetic field can apply an additional Lorentz force to the generated ions, which helps to more accurately control the trajectory and speed of the ions. At the same time, the energization of chamber 1 and cathode 21 forms an electric field, which can promote the movement of ions in the chamber. Furthermore, the cylindrical or annular shape of filament 211 can better form an axial helical motion, so that more electrons collide with gas atoms, thereby reducing the temperature or current required for the thermal ionization of filament 211, reducing energy consumption, and enabling more efficient ion source production. The electrons released by filament 211 can be more easily controlled. The magnetic field can affect the trajectory of electrons, causing them to travel along a helical path, increasing the collision of thermally ionized electrons with gas atoms, and improving ionization efficiency.

[0035] The variable magnetic field module consists of permanent magnets 22 and electromagnets 231. Electromagnets 231 are arranged in a circular array on the outer side of the fixed ring 23 and connected to the electromagnet power supply. They are independently controllable, and the on / off state and current magnitude of each electromagnet 231 can be controlled separately. An insulating material is provided between the electromagnets 231 and the chamber 1. A circular guide rail is provided on the fixed ring 23, and two permanent magnets 22 with opposite polarities are rotatably arranged inside the guide rail.

[0036] By utilizing the principle of a brushless motor, the direction of the magnetic field is changed by altering the on / off state of the electromagnet 231 and the magnitude of the current passing through it. This causes the permanent magnet 22 to rotate within the guide rail, generating a continuously rotating and changing variable magnetic field. This ensures the spiral motion path of high-energy electrons, extends the electron's path, and allows for better ionization of the electrons.

[0037] The head of the filament 211 is cylindrical or annular. The shape of the hot filament 211 does affect the effect of electron ejection from the filament 3. The ejection principle is to use an electric field to apply force to charged particles, so that the particles gain kinetic energy. Therefore, the effect of electron ejection depends on the electric field strength and direction. In order to achieve efficient ejection acceleration, it is necessary to ensure that the electric field strength is uniformly distributed on the surface of the hot filament 211 and parallel to the direction of electron movement. The shape of the hot filament will affect the electric field distribution on its surface. If the hot filament 211 is cylindrical, the electric field near its surface will be radially distributed. In order to accelerate electrons along the axial direction, the hot filament 211 needs to be designed as a cylinder with an appropriate length so that electrons can be smoothly ejected from the filament 3.

[0038] The chamber 1, cathode 21, fixing ring 23, and the outer shell of the deflector 3 are made of tungsten. Tungsten has a high melting point of 3410°C, which allows it to remain stable and resistant to deformation or calcination at high temperatures. This makes tungsten a suitable material for manufacturing parts in the ion implantation arc chamber that need to withstand high temperatures and ion impacts. Tungsten has good electrical conductivity and corrosion resistance, which helps reduce the heat generated during ion implantation and reduce corrosion of the material. Tungsten has a high density and a low coefficient of thermal expansion, which helps improve the thermal stability and mechanical strength of the arc chamber, thereby ensuring the stability and accuracy of the ion implantation process. It also has excellent mechanical and processing properties. Tungsten has high hardness and excellent mechanical properties, which can withstand the impact and stress generated during ion implantation. At the same time, tungsten has good processing properties and can be easily machined by cutting, drilling, and other mechanical processes. It does not contain substances harmful to the human body and the environment, meeting environmental protection requirements. In addition, tungsten is also a low-toxicity material with high safety during use.

[0039] Working Principle: This device uses a gas source as an ion source for semiconductor ion implantation. The gas to be ionized is introduced through inlet 11. The chamber 1 and cathode 21 are energized. A filament 211 is located inside the cathode 21. The filament 211 heats up when energized, generating electrons. The cathode 21 ejects high-energy electrons, causing gas atoms in the chamber to collide and lose electrons, forming gas ions. (See reference...) Figure 10 and 12 A fixed ring 23 is provided on the outer ring of the cathode 21. An array of electromagnets 231 in a circular pattern is provided on the fixed ring 23. Each electromagnet 231 is independently controlled. By controlling the on and off of each electromagnet 231 and the magnitude of its voltage and current, the permanent magnet 22 is driven by connecting the electromagnets 231 to the control mode of a brushless motor. The permanent magnet provides a continuously rotating magnetic field to the electrons emitted by the filament 3, so that a variable magnetic field that changes continuously clockwise or counterclockwise is formed in the chamber 1. The magnetic field can affect the trajectory of the electrons, causing them to travel along a spiral path, increasing the distance the electrons travel and the space they pass through, increasing the time the electrons stay in the chamber 1, improving the ionization efficiency of the electrons, reducing energy consumption, reducing the electron bombardment of the chamber 1, and increasing the service life of the chamber 1.

[0040] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0041] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A long-life pollution ion source device, comprising a chamber (1), characterized in that: The chamber (1) has a circular hole at one end, and the cathode (21) extends through the circular hole into the chamber (1). The cathode (21) is cylindrical, with a filament (211) inside and a fixing ring (23) on the outside. The fixing ring (23) is fixed to one end of the inner wall of the chamber (1). The chamber (1) has an air inlet (11) on one side and an arc-shaped slit (4) for leading out the ion source on one side. The chamber (1) and the cathode (21) are connected to the arc cavity power supply and the cathode power supply, respectively. The cathode (21) and the chamber (1) are not in contact. The filament (211) is connected to the filament power supply. A variable magnetic field module that can change the direction and intensity of the magnetic field in the chamber (1) is provided around the filament (211).

2. The long-life pollution ion source device according to claim 1, characterized in that: The variable magnetic field module consists of permanent magnet strips (230) placed on both sides of the filament (211) and attracting each other. The permanent magnet strips (230) extend along the direction of electron emission from the filament, and the magnetic field direction changes in the direction of extension of the mutually attracting permanent magnet strips (230).

3. The long-life pollution ion source device according to claim 2, characterized in that: The permanent magnet strip (230) is composed of small magnets that rotate clockwise and small magnets that rotate counterclockwise, respectively, arranged closely together.

4. The long-life pollution ion source device according to claim 1, characterized in that: The variable magnetic field module is an electromagnet (231). The electromagnets (231) are arranged in a circular array on the fixed ring (23) and are independently controlled. The power on / off of each electromagnet (231) and the magnitude of the current passing through it can be controlled separately. The electromagnets (231) are connected to the electromagnet power supply.

5. A long-life pollution ion source device according to claim 1, characterized in that: The variable magnetic field module consists of permanent magnets (22) and electromagnets (231). Electromagnets (231) are arranged in a circular array on the outer side of the fixed ring (23) and connected to the electromagnet power supply. They are independently controlled and can control the on / off state of each electromagnet (231) and the magnitude of the current passing through it. An insulating material is provided between the electromagnets (231) and the chamber (1). A circular guide rail is provided on the fixed ring (23), and two permanent magnets (22) with opposite polarities are rotatably arranged in the circular guide rail.

6. A long-life pollution ion source device according to claim 1, characterized in that: An insulating damping layer (13) is provided between the cathode (21) and the chamber (1) to fill the gap between them, so that the gas in the chamber (1) cannot flow out from between them.

7. A long-life pollution ion source device according to claim 1, characterized in that: A deflector (3) is provided at the end of the chamber (1) away from the cathode (21).

8. A long-life pollution ion source device according to claim 1, characterized in that: The head of the filament (211) is cylindrical or annular.

9. A long-life pollution ion source device according to any one of claims 1-8, characterized in that: The chamber (1), cathode (21), fixing ring (23) and the outer shell of the deflector (3) are made of tungsten.

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