A feedthrough ceramic electrode device for an ion implanter linear accelerator

Abstract

This utility model discloses a feedthrough ceramic electrode device for an ion implanter linear accelerator in the field of high-voltage vacuum feedthrough technology. It includes: a central high-voltage electrode, cylindrical in shape and made of highly conductive oxygen-free copper; an insulating ceramic column, corrugated in shape, surrounding the main insulating portion of the central high-voltage electrode, with a hermetically sealed connection between the central high-voltage electrode and the inner hole of the insulating ceramic column; a metal threaded outer shell, surrounding the insulating ceramic column and providing mechanical support, mounting interface, and flange, with a sealing groove equipped with an elastomer at the flange, and a hermetically sealed connection between the insulating ceramic column and the metal threaded outer shell; and a metal threaded limiting pin, located on the end sidewall of the metal threaded outer shell. This utility model provides a special device for safely and reliably introducing high voltage to the internal electrode within the high-vacuum accelerator pipeline, between it and an external power source, while maintaining vacuum sealing and excellent electrical insulation, effectively achieving integrated high-voltage insulation and vacuum sealing.

Description

Technical Field

[0001] This utility model relates to a feedthrough ceramic electrode device for a linear accelerator in an ion implanter, belonging to the technical field of high-voltage vacuum feedthrough devices. Background Technology

[0002] The linear accelerator in an ion implanter performs two functions: 1. It accelerates the ion beam using radio frequency energy provided by a series of radio frequency accelerator devices; 2. It uses a series of electrostatic quadrupole lenses to radially focus the ion beam. The radio frequency accelerators and electrostatic quadrupole lenses are assembled together to form a linear accelerator assembly, which is mounted on a linear accelerator base. The front-end component of the linear accelerator assembly generates ions of the desired dopant element, which are then passed through the linear accelerator assembly to form an ion beam with the required energy and density, and fed into the back-end component.

[0003] In linear accelerators (medium-high energy type) for ion implanters, specifically in radio frequency quadrupole linear accelerators or drift tube linear accelerators, a series of accelerating gaps need to be set along the acceleration path. Each accelerating gap typically consists of one or more pairs of electrodes, requiring the application of a specific radio frequency voltage (reaching the 20KV level) to establish an accelerating electric field within the gap. Feedthru ceramic high-voltage electrode devices are key interface components used to safely and reliably feed electrical energy from an external high-voltage power supply to these accelerating electrodes located in an ultra-high vacuum environment. They are indispensable fundamental components for achieving the step-by-step acceleration of the ion beam in multi-stage accelerating units, ultimately reaching the required high energy. The core challenge in integrating high-voltage insulation and vacuum sealing in feedthru ceramic electrode devices lies in simultaneously solving three problems: creepage distance under 20KV high voltage, insulation strength, and permanent sealing in an ultra-high vacuum environment. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a feedthrough ceramic electrode device for a linear accelerator in an ion implanter. This device safely and reliably introduces high voltage to the internal electrode between the accelerator pipe and the external power source, while maintaining vacuum sealing and excellent electrical insulation. It effectively achieves the integration of high voltage insulation and vacuum sealing, solving the three problems of creepage distance, insulation strength, and permanent sealing under 20KV high voltage and ultra-high vacuum environment.

[0005] To achieve the above objectives, this utility model employs the following technical solution:

[0006] In a first aspect, this utility model provides a feedthrough ceramic electrode device for an ion implanter linear accelerator, comprising:

[0007] Central high-voltage electrode: cylindrical in shape, made of oxygen-free copper, a highly conductive metal;

[0008] Insulating ceramic column: It is corrugated in shape and surrounds the main insulating part of the central high voltage electrode. The central high voltage electrode and the inner hole of the insulating ceramic column are hermetically sealed.

[0009] A metal threaded housing surrounds an insulating ceramic column, providing mechanical support, mounting interfaces, and a flange, with a sealing groove equipped with an elastomer at the flange. The insulating ceramic column and the metal threaded housing are hermetically sealed.

[0010] Metal threaded limit pin: located on the end side wall of the metal threaded housing.

[0011] Furthermore, the insulating ceramic column has an insulation strength greater than 30 kV / mm, a dielectric constant of 9.0–9.5, and an outgassing rate of less than 1 × 10⁻¹⁰ Pa·m. 3 / s·cm 2 Flexural strength ≥300MPa and coefficient of thermal expansion 7.5~8.5×10 -6 Made of / K material.

[0012] Furthermore, the metal threaded limiting pin and the metal threaded outer shell have an elastic thread engagement structure.

[0013] Furthermore, a gas-tight connection is formed between the central high-voltage electrode and the inner hole of the insulating ceramic column using a molybdenum-manganese metallization layer and a precious metal brazing filler metal.

[0014] Furthermore, the outer wall of the insulating ceramic column and the metal threaded outer shell are vacuum brazed and sealed by a composite metallization layer with a matching coefficient of thermal expansion.

[0015] Furthermore, the end of the central high-voltage electrode is machined into a spherical crown-shaped smooth curved surface.

[0016] Furthermore, the elastomer is a fluororubber O-ring.

[0017] Compared with the prior art, the beneficial effects achieved by this utility model are as follows:

[0018] This invention is a special device that safely and reliably introduces high voltage to the internal electrodes within the high vacuum accelerator pipeline, between the external power source and the accelerator, while maintaining vacuum sealing and excellent electrical insulation. It effectively integrates high-voltage insulation and vacuum sealing, and solves the problems of creepage distance, insulation strength, and permanent sealing under 20KV high voltage and ultra-high vacuum environment. This invention is used in a special ceramic metallization process to ensure reliability under high voltage. The structural design optimizes the electric field distribution to reduce partial discharge. In addition to ion implanters, its application scenarios may be extended to other high-energy physics equipment or semiconductor manufacturing devices. Attached Figure Description

[0019] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments and descriptions of this utility model are used to explain this utility model and do not constitute an undue limitation thereof. In the drawings:

[0020] Figure 1 This utility model provides an embodiment of the overall structural diagram of an ion implanter linear accelerator assembly with a feedthrough ceramic electrode device.

[0021] Figure 2 A structural diagram of the feedthrough ceramic electrode device for an ion implanter linear accelerator provided in this embodiment of the present invention;

[0022] In the diagram: 1. Metal threaded outer shell; 2. Metal threaded limit pin; 3. Insulating ceramic post; 4. Central high-voltage electrode. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0024] The following detailed description is exemplary and intended to provide further detailed explanation of the present invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this invention.

[0025] Example:

[0026] A feedthrough ceramic electrode device for a linear accelerator in an ion implanter includes a metal threaded outer shell 1, a metal threaded limiting pin 2, an insulating ceramic column 3, and a central high-voltage electrode 4, wherein:

[0027] Central high-voltage electrode 4: It is columnar in shape and made of oxygen-free copper, a highly conductive metal. It is the conductor that introduces 20KV high voltage into the accelerator.

[0028] Insulating ceramic column 3: The main insulating part surrounding the central high-voltage electrode 4. It is corrugated in shape, increasing the creepage distance while providing axial flexibility to alleviate thermal stress. The ceramic corrugated tube absorbs the difference in thermal expansion through axial flexible expansion and contraction. The ceramic material is selected with extremely high insulation strength (>30KV / mm), low dielectric loss (dielectric constant 9.0~9.5), and excellent vacuum performance (outgassing rate less than 1×10-10 Pa·m). 3 / s·cm 2Good mechanical strength (bending strength ≥300MPa) and a coefficient of thermal expansion that matches that of metals (7.5~8.5×10). -6 Materials with a high purity of alumina ceramics (Al2O3) such as / K.

[0029] Threaded metal housing 1: A metal structure surrounding the insulating ceramic column 3. It provides mechanical support and mounting interfaces, with flanges (ISO standard) for bolting to the accelerator's vacuum chamber wall. The vacuum sealing surface, including the flange face, has sealing grooves (equipped with elastomeric O-rings such as fluororubber). In this design, the threaded metal housing 1 and the central high-voltage electrode 4 are typically made of non-magnetic, highly conductive, weldable metals with CTE matching to the ceramic, such as oxygen-free copper.

[0030] External electrical connection point: includes a metal threaded limit pin 2 with a terminal block. The metal threaded limit pin 2 and the metal threaded outer shell 1 are designed with an elastic thread engagement structure to allow for slight axial displacement.

[0031] The ceramic-metal sealing assembly consists of two seals: an inner seal (the hermetically sealed connection between the central high-voltage electrode 4 and the inner bore of the insulating ceramic pillar 3) and an outer seal (the hermetically sealed connection between the insulating ceramic pillar 3 and the metal threaded outer shell 1). These two seals are crucial for achieving vacuum sealing and high-voltage insulation, and are achieved through a metallization and brazing process. Unique ceramic metallization (e.g., sintering a molybdenum-manganese layer on the ceramic surface) and subsequent brazing (using silver-copper solder or gold-based solder) processes ensure a permanent, hermetically sealed connection between the ceramic and the metal shell, and between the ceramic and the central electrode, characterized by excellent hermetical tightness, high mechanical strength, high pressure resistance, and thermal shock resistance.

[0032] It should be noted that the central high-voltage electrode 4 and the inner hole of the insulating ceramic column 3 are connected by a molybdenum-manganese metallization layer and a precious metal brazing filler (such as AgCu28) to form a gas-tight connection; the outer wall of the insulating ceramic column 3 and the metal threaded outer shell 1 are vacuum brazed and sealed by a composite metallization layer with a matching coefficient of thermal expansion.

[0033] Electric field distribution optimization: Under 20KV high voltage, concentrated electric field can lead to partial discharge (corona discharge) and even breakdown. The optimized electrode shape avoids sharp corners and uses a large radius of curvature; an equalizing ring is incorporated; and the corrugated design of the ceramic insulator is used to equalize the electric field, increase the effective creepage distance, and suppress corona discharge. It should be noted that the continuous arc-shaped corrugated grooves of the insulating ceramic column 3 form a stepped creepage path; the end of the central high-voltage electrode 4 is machined into a smooth, spherical cap-shaped surface to suppress tip discharge.

[0034] Ultra-high vacuum compatibility: All materials (ceramics, metals, solder) must have extremely low gas permeability and outgassing rates. The manufacturing process (such as cleaning and baking) must ensure that the components, after being installed in the accelerator and undergoing a standard baking procedure, can achieve and maintain the required ultra-high vacuum level (typically <10). -7 Pa or lower).

[0035] Mechanical stability and reliability: The device must withstand vibration, thermal cycling (start-up / shutdown, baking), and internal stress (caused by CTE differences). Ensure structural strength design, stress relief design, and processes that guarantee long-term reliability.

[0036] This design utilizes a feedthrough ceramic electrode assembly to efficiently and with low loss transmit a 20kV high voltage from the atmospheric power supply to the electrodes within the vacuum chamber. As a physical barrier, it completely isolates the accelerator interior (ultra-high vacuum) from the external atmospheric environment, preventing gas leakage into the vacuum chamber and maintaining the necessary vacuum level. It provides extremely reliable high-voltage electrical insulation between the central high-voltage electrode (20kV) and the grounded metal casing / accelerator cavity, preventing high-voltage short circuits to ground or surface discharges (flashovers). It also provides robust mechanical support and positioning for the internal accelerating electrodes.

[0037] The feedthrough ceramic electrode, equipped with an O-ring, is mounted on the linear accelerator. High vacuum is achieved by pressing the feedthrough ceramic electrode against the O-ring. Electrical energy, at 20 kV, is transferred from an external high-voltage power supply (RF) to specific accelerating electrodes inside the accelerator, establishing an accelerating electric field. This is a special device used to safely and reliably introduce high voltage (20 kV) to internal electrodes between a high-vacuum environment (inside the accelerator tube) and an atmospheric environment (external power supply), while maintaining vacuum sealing and excellent electrical insulation. Its core application in ion implanter linear accelerators is to safely and reliably transfer electrical energy from an external high-voltage power supply (20 kV) to specific accelerating electrodes inside the accelerator while maintaining an ultra-high vacuum environment. In semiconductor equipment, this high-voltage vacuum feedthrough device directly affects ion beam quality and equipment stability, making it a critical component.

[0038] As is known from common technical knowledge, this utility model can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this utility model or its equivalents are included in this utility model.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of this utility model. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this utility model should be covered within the protection scope of the claims of this utility model.

Claims

1. A feedthrough ceramic electrode device for an ion implanter linear accelerator, characterized in that, include: Central high voltage electrode (4): It is columnar in shape and made of oxygen-free copper, a highly conductive metal; Insulating ceramic column (3): It is corrugated and surrounds the main insulating part of the central high voltage electrode (4). The central high voltage electrode (4) and the inner hole of the insulating ceramic column (3) are airtightly connected. A metal threaded housing (1) surrounds the insulating ceramic column (3), providing mechanical support, mounting interface and flange, and the flange is provided with a sealing groove equipped with an elastomer. The insulating ceramic column (3) and the metal threaded housing (1) are hermetically sealed. Metal threaded limit pin (2): located on the end side wall of the metal threaded outer shell (1).

2. The ion implanter linear accelerator feedthrough ceramic electrode assembly of claim 1, wherein: The insulating ceramic column (3) has an insulation strength greater than 30KV / mm, a dielectric constant of 9.0~9.5, and an outgassing rate of less than 1×10-10Pa·m. 3 / s·cm 2 Flexural strength ≥300MPa and coefficient of thermal expansion 7.5~8.5×10 -6 Made of / K material.

3. The ion implanter linear accelerator feedthrough ceramic electrode assembly of claim 1, wherein: The metal threaded limit pin (2) and the metal threaded outer shell (1) have an elastic thread engagement structure.

4. The ion implanter linear accelerator feedthrough ceramic electrode assembly of claim 1, wherein: The central high-voltage electrode (4) and the inner hole of the insulating ceramic column (3) are connected by a molybdenum-manganese metallization layer and a precious metal brazing filler metal to form a hermetically sealed connection.

5. The ion implanter linear accelerator feedthrough ceramic electrode assembly of claim 1, wherein: The outer wall of the insulating ceramic column (3) and the metal threaded outer shell (1) are vacuum brazed and sealed by a composite metallization layer with a matching coefficient of thermal expansion.

6. The ion implanter linear accelerator feedthrough ceramic electrode assembly of claim 1, wherein: The end of the central high-voltage electrode (4) is machined into a spherical crown-shaped smooth curved surface.

7. The ion implanter linear accelerator feedthrough ceramic electrode assembly of claim 1, wherein: The elastomer is a fluororubber O-ring.

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