Ion generator device
Patent Information
- Authority / Receiving Office
- TW · TW
- Patent Type
- Applications
- Current Assignee / Owner
- FIDELITY SEMICONDUCTOR CORP
- Filing Date
- 2025-01-03
- Publication Date
- 2026-07-16
AI Technical Summary
Existing ion generating devices in semiconductor fabrication suffer from low plasma ionization efficiency, leading to inefficient ion generation, frequent thin film formation on chamber walls, and reduced service life due to short circuits, which increases energy consumption and manufacturing costs.
The ion generating device incorporates a guide member around the cathode to alter the electron path, ensuring electrons move towards gas inlets more effectively, enhancing ionization efficiency by 40% to 100% and reducing thin film formation, while using a repeller and symmetric gas inlets for uniform gas distribution.
This design increases ion generation efficiency, reduces energy consumption, and extends the device's service life by minimizing arc formation and thin film deposition, thereby saving costs.
Smart Images
Figure TWG2TA001067758_001 
Figure TWG2TA001067758_002 
Figure TWG2TA001067758_003
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor device fabrication technology, and more specifically, to an ion generating device used in ion implantation machines to prepare ion sources. Prior Technology
[0002] In semiconductor device manufacturing, ion implantation is used to dope semiconductors with impurities. Ion implantation systems are often used to dope workpieces (such as semiconductor wafers) with ions from an ion beam to produce n-type or p-type material doping, or to form passivation layers during integrated circuit fabrication. This beam processing is often used to selectively implant impurities of a specified dopant material into a wafer at a predetermined energy level and a controlled concentration to produce semiconductor material during integrated circuit fabrication. When used to dope semiconductor wafers, the ion implantation system sprays a selected type of ions into the workpiece to produce the desired intrinsic material. For example, implanting ions generated from a source material (such as antimony, arsenic, or phosphorus) produces an "n-type" intrinsic material wafer, while a "p-type" intrinsic material wafer is often generated from ions generated from a source material (such as boron, gallium, or indium).
[0003] A typical ion implantation system includes an ion source, an ion extraction device, a mass analysis device, a beam delivery device, and a wafer processing device. The ion source generates ions of the desired atomic or molecular dopant type. These ions are extracted from the source by an extraction system (typically a set of electrodes) to form an ion beam, which powers and guides the ion stream from the source. The desired ions are separated and extracted from the ion beam in a mass analysis device, typically a magnetic dipole that performs mass dispersion or separation of the extracted ion beam. The beam delivery device (typically a vacuum system containing a series of focusing devices) delivers the ion beam to the wafer processing device while maintaining the desired properties of the ion beam. Finally, the semiconductor wafer is transferred into or out of the wafer processing device via a wafer handling system, which may include one or more robotic arms for placing the wafer to be processed in front of the ion beam and removing the processed wafer from the ion implanter.
[0004] Figure 1 is a schematic cross-sectional view of a conventional ion generating device. The existing ion generating device 10 includes: an ion source arc chamber 12 formed by an arc chamber housing 11; a thermionic emitter including a filament 21 and a cathode 22, the filament 21 and cathode 22 being disposed at one end of the ion source arc chamber 12; the ion source arc chamber 12 also has at least one gas inlet 13 for providing source gas; a repeller 23 is disposed at the other end of the ion source arc chamber 12, with the repeller 23 and cathode 22 facing each other, possibly having the same potential or relative floating potentials. In practice, dual magnets 30 are respectively disposed outside the arc chamber housing 11 corresponding to the repeller 23 and cathode 22. In practical applications, the filament 21 is heated to the emission temperature for thermionic emission by a power supply. The electrons emitted from the filament 21 toward the cathode 22 are accelerated by the voltage difference between the filament 21 and the cathode 22 until the cathode 22 itself generates thermionic emission.
[0005] Please refer to Figures 2 and 3. The cathode 22 generates initial electrons 41 and is attracted by the electric field (EArc). The electron movement path is initiated by the voltage of the arc chamber shell 11 and the source magnet 30. The electrons tend to move towards the side wall of the arc chamber shell 11 near the cathode 22. At this time, only a few effective electrons 41 react with the gas 42 to form ions 43 and form plasma in the ion source arc chamber 12. Most ineffective electrons 41 are attracted to the side wall and form an arc current. Due to design flaws in the existing ion generating device 10, electrons 41 tend to move towards the side wall of the arc chamber housing 11 near the cathode 22, resulting in low efficiency in the effective reaction of electrons with gas to form ions. Unionized gas molecules easily deposit within the wall of the ion source arc chamber 12 to form a thin film. When the film reaches a certain thickness, it may come into contact with the cathode. In severe cases, this can easily lead to a short circuit between the cathode 22 and the arc chamber housing 11. In this case, the ion generating device 10 needs to be removed for cleaning, and the cathode needs to be replaced, thus greatly shortening the service life of the existing ion generating device 10. Summary of the Invention
[0006] The purpose of this invention is to provide an ion generating device that improves plasma ionization efficiency. Compared with existing ion generating devices, it can increase ion generation efficiency by 40% to 100%, and reduce the thin film generated by unionized gas deposition in the cavity wall. At the same time, it can obtain a larger ion beam current to improve the generation rate of the ion source.
[0007] Another objective of this invention is to provide an ion generating device that improves plasma ionization efficiency under the same ion beam current, reduces the heating current of the filament and cathode, saves reaction gas, thereby saving energy consumption and manufacturing costs, and increasing the service life of the ion generating device.
[0008] To achieve the above objectives, the present invention provides an ion generating device, comprising: an arc chamber housing forming an ion source arc chamber; a thermionic emitter including a filament and a cathode disposed at one end of the ion source arc chamber; and a guide member disposed around the cathode to form a guide channel, wherein the top surface of the guide member protrudes above the upper surface of the cathode. The ion source arc chamber has at least two gas inlets for supplying gas, which are symmetrically arranged on both sides of the cathode's central extension line to provide gas more uniformly to the ion source arc chamber; and the guide member facilitates the movement of electrons towards the gas inlets, thereby improving the gas ionization efficiency.
[0009] Optionally, the top surface of the guide is 0.1 mm to 50 mm above the upper surface of the cathode.
[0010] Optionally, the thickness of the guide is between 0.1 mm and 10 mm.
[0011] Optionally, the cathode and the guide are both mounted on a support plate; the gap between the guide and the cathode is between 0.1 mm and 10 mm; and the guide and the arc chamber housing are spaced between 0.1 mm and 10 mm apart.
[0012] Optionally, at least one second gas inlet is provided on each of the two sides of the surface of the gas inlets provided in the ion source arc chamber.
[0013] Compared to prior art, the ion generating device of the present invention, due to the arrangement of the guide member, changes the influence of the electric field within the ion source arc on electrons, thereby increasing the average movement path of electrons and controlling the movement path of hot electrons to pass through the position of the highest peak of gas molecules, allowing electrons and gas molecules to react more effectively. This improves the overall ionization efficiency within the ion source arc chamber. Compared to existing ion generating devices, the present invention can increase ion generation efficiency by 40% to 100%, reduce the thin film formation caused by unionized gas deposition within the ion source arc chamber wall, and achieve a larger ion beam current, reduce the heating current of the filament and cathode, and save on reaction gas. This can save energy consumption and manufacturing costs, thereby increasing the service life of the ion generating device. Simple Explanation of the Diagram
[0014] Figure 1 is a cross-sectional schematic diagram of a conventional ion source generating device. Figure 2 is a schematic diagram of electrons generated at the cathode in Figure 1 and attracted by the electric field. Figure 3 is a schematic diagram of the electron path in Figure 2. Figure 4 is a cross-sectional schematic diagram of the ion source generating device in this case. Figure 5 is a cross-sectional schematic diagram of the cathode and guide in this case. Figure 6 is a schematic diagram of the gas inlet configuration in this case. Figure 7 is a schematic diagram of the electronic path in Figure 4. Figure 8 is a schematic diagram of the electronic path in Figure 4 (II). Implementation
[0015] The following details various embodiments of the present invention, illustrated in the accompanying drawings. Besides these detailed descriptions, the present invention can be widely implemented in other embodiments, and any easy substitutions, modifications, or equivalent changes to the described embodiments are included within the scope of the present invention and are subject to the claims. In the description of the specification, many specific details are provided to give the reader a more complete understanding of the present invention; however, the present invention may still be implemented even with some or all of these specific details omitted. Furthermore, well-known steps or elements are not described in the details to avoid unnecessarily limiting the present invention. Identical or similar elements in the drawings will be represented by the same or similar symbols. It is particularly important to note that the drawings are for illustrative purposes only and do not represent the actual size or number of elements; some details may not be fully drawn for the sake of simplicity.
[0016] First, please refer to Figures 4-6. In practical application, the ion generating device 100 of this invention includes: an arc chamber housing 110, inside which an ion source arc chamber 120 is formed. A thermionic emitter 200 includes a filament 210 and a cathode 220, the cathode 220 being disposed at one end of the ion source arc chamber 120; the cathode 220 has a hollow bottom, and the filament 210 is positioned within the hollow bottom region of the cathode 220 via a filament holder 211. In practice, the filament 210, cathode 220, and arc chamber housing 110 are not connected and each has its own external voltage. The filament 210 is heated to the emission temperature for thermionic electron generation by a power supply. The voltage difference between the filament 210 and the cathode 220 accelerates the electrons emitted from the filament 210 toward the cathode 220 until the cathode 220 itself generates thermionic electrons.
[0017] A guide member 500 is disposed around the cathode 220 to form a guide channel, and the top surface 510 of the guide member 500 protrudes higher than the upper surface 221 of the cathode 220. The guide member 500 forms a guide channel to guide the movement direction of the thermionic electrons 410 of the cathode 220 when they are attracted by the electric field (EArc). The ion source arc chamber is provided with at least two gas inlets 130 for supplying gas 420. These gas inlets 130 are symmetrically arranged on both sides of the central extension line of the cathode 220 to provide gas more evenly into the ion source arc chamber 120. Through the action of the guide member 500, the electrons 410 generated by the cathode 220 move as far as possible towards the gas inlets 420, thereby improving the ionization efficiency of the gas.
[0018] In practical applications, the guide 500 can be made of tungsten or graphite. The top surface 510 of the guide 500 is approximately 0.1 mm to 50 mm higher than the upper surface 221 of the cathode 220; the thickness of the guide 500 is approximately 0.1 mm to 10 mm.
[0019] In practical application, the cathode 220 and the guide 500 can be jointly mounted on a support disk 240, which can be a graphite support disk; the gap D1 between the guide 500 and the cathode 220 is between approximately 0.1 mm and 10 mm to better form a guide channel; the guide 500 and the arc chamber housing 110 are provided with a gap D2 between approximately 0.1 mm and 10 mm to avoid short circuits.
[0020] As disclosed in existing known applications, the ion source arc chamber 120, which serves as an ion source, has an opening at one end. The cathode 220 is disposed at one end within the ion source arc chamber 120. Electrons emitted by the cathode 220 generate plasma within the ion source arc chamber 120. Finally, ions and / or other impurities generated in the ion source arc chamber 120 are discharged through an extraction aperture (not shown) on one side of the arc chamber housing 110.
[0021] In practical application, a repeller 230 is also provided inside the ion source arc chamber 120 and coupled to the arc chamber housing 11. The repeller 230 is arranged opposite to the cathode 220, and the repeller 230 and the cathode 220 are biased at the same potential at the other end of the ion source arc chamber 120 to repel high-energy electrons formed in the ion source arc chamber 120. In the technical implementation of this invention, the repeller 230, the cathode 220, and the guide 500 are at the same potential and can be biased by applying the same potential or by each being connected to an external potential.
[0022] In practice, two source magnets 300 are respectively disposed outside the arc chamber housing 110 corresponding to the repulsive pole 230 and the cathode 220. In some other known embodiments, one or more source magnets 300 can be used to generate a magnetic field. The generation efficiency of plasma in the ion source arc chamber 120 can be improved by applying a magnetic field with the source magnets 300. The direction of the magnetic field applied by these source magnets 300 corresponds to the length direction of the aforementioned extraction pores.
[0023] In practical application, unlike the conventional ion source arc chamber 12 where the gas inlet 13 is directly opposite the extension line of the center of the cathode 22 (as shown in Figure 1) (there may be two gas inlets 13 in practice), regardless of the number of gas inlets 13, they are all directly opposite the extension line of the center of the cathode 22.
[0024] In this embodiment, the ion source arc chamber 120 has at least two gas inlets 130. These gas inlets 130 are positioned between the central extension line of the cathode 220 and the arc chamber housing 110, and are symmetrically arranged on both sides of the central extension line of the cathode 220 (as shown in Figure 6), which allows for a more uniform supply of source gas to the interior of the ion source arc chamber 120. In some other embodiments, more than four gas inlets 130 may be used, but these gas inlets 130 are symmetrically positioned on both sides of the central extension line of the cathode 220.
[0025] In practical application, the ion source arc chamber 120 has at least one second gas inlet 131 on each of the two sides of the aforementioned gas inlet 130, as shown in Figure 6. There are four pairs of corresponding second gas inlets 131 on the sides. Through these second gas inlets 131, the source gas can be supplied to the interior of the ion source arc chamber 120 more evenly.
[0026] Specifically, gas inlets 130 (including second gas inlets 131) are connected to gas manifolds, through which source gas for ionization is supplied to the ion source arc chamber 120. The gas manifolds can provide source gas in the form of gaseous compounds or vapors, so that the gas can be ionized in the ion source arc chamber 120.
[0027] Please refer to Figures 7 and 8 for a schematic diagram of the electron path. The electrons 410 generated by the cathode 220 are attracted by the electric field (EArc) (as shown in Figure 4). The top surface 510 of the guide member 500 protrudes above the upper surface 221 of the cathode 220, and the guide member 500 acts like a conduit channel, allowing the electrons 410 generated by the cathode 220 to diverge outward from the top of the guide member 500. Gas 420 is then uniformly supplied to the interior of the ion source arc chamber 120 through the gas inlets 130 (second gas inlets 131). Technically, this invention alters the influence of the electric field (EArc) within the ion source arc chamber 120 on the electrons 410 generated by the cathode 220 by setting the guide member 500. This increases the average upward movement path of the electrons 410 and controls the electrons 410 to pass through the position of the highest molecular weight of the gas 420—the gas inlet 130 (as shown in Figures 7 and 8). Under the same energy consumption and gas supply, more effective electrons 410 will react with the gas 420 to form ions 430, thereby improving the overall ionization efficiency within the ion source arc and increasing the ion 430 generation efficiency by 40% to 100%. Conversely, with the increased ion 430 generation efficiency, the amount of gas 420 used can also be reduced.
[0028] The technology described in this invention can be applied to known ion generating devices 100. Essentially, by guiding the direction of the thermionic electrons emitted by the cathode 220 through the guide member 500, the chances of electrons reacting with the gas will be increased. Compared to existing known devices, this technology will reduce the number of ineffective electrons attracted to the sidewalls and forming arc currents, while also reducing the thin film formation caused by the deposition of unionized gas.
[0029] Compared to prior art, the ion generating device of the present invention has the advantage that, due to the arrangement of the guide, the influence of the electric field in the ion source arc chamber on electrons is changed, thereby increasing the average movement path of electrons and controlling the position of the electron movement path to pass through the peak of gas molecules, allowing electrons and gas molecules to react more effectively. This improves the overall ionization efficiency in the ion source arc chamber, reduces the thin film generated by the deposition of unionized gas in the chamber wall, and achieves a larger ion beam current, reduces the heating current of the filament and cathode, and saves reaction gas. This can save energy consumption and manufacturing costs, thereby increasing the service life of the ion generating device.
[0030] The embodiments disclosed above are merely illustrative of the principles, features, and effects of the present invention and are not intended to limit the scope of implementation of the present invention. Any person skilled in the art may modify and alter the above embodiments without departing from the spirit and scope of the present invention. Any equivalent changes and modifications made using the content disclosed in this invention shall still be covered by the following patent application scope.
[0031] 10, 100: Ion generating device 11, 110: Arc chamber shell 12, 120: Ion source arc chamber 13, 130: Gas Inlet 131: Second gas inlet 20, 200: Thermionic emitters 21, 210: Filament 211: Filament Holder 22, 220: Cathode 221: Upper surface 23, 230: Repulsion pole 240: Support level 30, 300: Source magnets 41, 410: Electronics 42, 420: Gas 43, 430: Ions 500: Guide component 510: Top face D1: Gap D2: Spacing
Claims
1. An ion generating device, comprising: An arc chamber shell, which forms an ion source arc chamber; A thermionic emitter includes a filament and a cathode disposed at one end of an ion source arc chamber; a guide member is arranged around the cathode to form a guide channel, and the top surface of the guide member protrudes above the upper surface of the cathode, the top surface of the guide member being 0.1 mm to 50 mm higher than the upper surface of the cathode; wherein, the ion source arc chamber has at least two gas inlets for supplying gas, the gas inlets being symmetrically arranged on both sides of the central extension line of the cathode, for supplying gas to the ion source arc chamber more uniformly; and through the action of the guide member, electrons are moved as far as possible towards the gas inlets, thereby improving the ionization efficiency of the gas.
2. The ion generating apparatus as described in claim 1, wherein, The thickness of the guide is between 0.1 mm and 10 mm.
3. The ion generating apparatus as described in claim 1, wherein, The cathode and the guide are mounted together on a support plate.
4. The ion generating apparatus as described in claim 3, wherein, The gap between the guide and the cathode is between 0.1 mm and 10 mm.
5. The ion generating apparatus as described in claim 3, wherein, The guide component has a gap of 0.1 mm to 10 mm between it and the arc chamber housing.
6. The ion generating apparatus as described in claim 1, wherein, At least one second gas inlet is provided on each of the two sides of the surface of the gas inlets provided in the ion source arc chamber.