Replaceable guard structure for electrostatic deflection plates

Abstract

The application discloses a replaceable protection structure of an electrostatic deflection plate, which comprises an electrode plate body, a slot is formed on a beam-accepting surface of the electrode plate body, a composite protection layer is arranged in the rectangular slot, and the composite protection layer comprises a pullable protection layer and a conductive pad from outside to inside along a beam transmission direction; the conductive pad is located at the bottom of the slot; the surface of the protection layer is basically flush with the beam-accepting surface of the electrode plate body; a matching gap is left between the side wall of the slot and the side wall of the protection layer and the side wall of the conductive pad; an elastic conductive track is arranged on the side wall of the slot, the elastic conductive track spans the matching gap and is in contact with the side wall of the protection layer and the side wall of the conductive pad, so as to connect the side walls of the protection layer and the conductive pad with the side wall of the slot as a bridge. The application can effectively solve the problems of the prior art, such as electric field distortion, micro-discharge and breakdown, maintenance difficulty, high cost and the like caused by sputtering pollution of the electrostatic deflection plate.

Description

Technical Field

[0001] This invention relates to a replaceable protective structure for an electrostatic deflection plate, belonging to the field of charged particle beam transmission and control technology. Background Technology

[0002] Ion implanters are key equipment in semiconductor chip manufacturing. They generate ions through an ion source, adjust ion energy using an acceleration and deceleration system, laterally focus the beam, screen ion types and energies using a magnetic field analyzer, and finally, use a beam scanning deflector to uniformly scan the ion beam across the wafer surface for precise implantation of doped elements. Beam scanning deflectors employ several methods, including electrostatic scanning, magnetic field scanning, and electromagnetic hybrid scanning. Electrostatic scanning deflectors (or simply electrostatic deflectors) are widely used due to their simple structure. For example... Figure 1 As shown, the electrostatic deflection plate is typically composed of a pair of parallel positive electrode body 1 and negative electrode body 2, which are disposed at the end of the beamline. An electrostatic voltage is applied between the electrode plates, causing the ion beam formed by charged particles 11 to deflect in a plane perpendicular to the beam transmission direction 12, thereby performing a uniform scan on the wafer surface.

[0003] During ion implantation, scattered ions from the beam edge, which deviate from the main beam trajectory due to lateral divergence, and secondary ions generated by collisions between residual gas molecules and beam ions, continuously bombard the surface of the electrostatic deflector plate facing the beam. This bombardment causes sputtering of material on the electrode plate surface, and the sputtering products not only contaminate the electrode surface but also deposit to form a contamination layer. With prolonged use, the contamination and sputtering damage on the electrode plate surface gradually accumulate, leading to the following problems: First, it alters the surface morphology of the electrode plate, and the accumulation of contamination and damage layers easily causes distortion of the electric field distribution. The uniformity of the electric field is strongly affected by the surface condition of the electrode plate; even minor changes in surface morphology or uneven contamination layer thickness can cause nonlinear distortion of the deflection electric field, thus causing the ion beam deflection trajectory to deviate from the designed path, resulting in uneven implantation dose distribution on the wafer surface. Secondly, when sputtering-induced contamination and damage to the electrode plate surface accumulate to a certain extent, the contamination and damage layers, under the influence of the deflection electric field, induce local electric field concentration, forming a local potential difference. This frequently triggers micro-discharges and arc erosion on the electrode plate surface. When the local potential difference further exceeds the breakdown threshold, the electrode plate surface will break down. Micro-discharges and breakdown phenomena create a vicious cycle of "contamination damage - micro-discharge - more severe contamination damage - more frequent micro-discharges," which continuously affects the stability of the deflection electric field and gradually shortens the service life of the electrostatic deflection plate. This problem is more pronounced under conditions such as strong beam current, heavy ion implantation, strong deflection electric field, and long-term operation. Thirdly, once the sputtering and contamination on the electrode plate surface reaches a certain level, maintenance or replacement is necessary. Traditional electrostatic deflection plates have an integral structure. When replacing them, the entire deflection electrode assembly must be removed from the vacuum chamber and replaced with a new integral spare part. The maintenance operation is complex and time-consuming, seriously affecting equipment utilization and production capacity.

[0004] Existing solutions to sputter contamination problems on electrostatic deflector plates mainly include: regular cleaning of the electrode plate, coating the electrode plate surface with a protective coating, or using sputter-resistant materials (such as graphite, molybdenum, etc.) for the entire electrode plate. However, when using conventional metal materials to manufacture electrode plates, sputter contamination requires disassembling the entire electrode plate for chemical treatment after regular cleaning, which is cumbersome. While offline chemical cleaning can temporarily alleviate the problem, repeated chemical cleaning can damage the electrode surface precision, leading to deterioration of surface roughness and degradation of electric field uniformity, resulting in a gradual decrease in the electrode plate's performance—a short-term solution. However, if cleaning is not done promptly, the overall electrode plate material performance will gradually deteriorate until failure. While coating the surface with a protective coating can delay sputtering, the protective lifespan of the coating is limited, and it is prone to peeling if the adhesion strength between the coating and the substrate is insufficient. Once peeled off, the electrode plate loses its protection and still faces sputter contamination, requiring replacement of the entire electrode, resulting in high overall maintenance costs. If sputter-resistant conductive materials such as graphite or molybdenum are used throughout to improve sputter resistance, the material and processing costs will increase significantly, and the entire system will need to be replaced if damaged. A common limitation of the aforementioned existing technologies is the use of a traditional integrated electrostatic deflector plate design. Figure 1 It is difficult to physically separate the functions of withstanding sputtering from providing the deflection electric field, which leads to either sacrifices in maintenance efficiency, protection reliability, or electrode material cost. This invention, based on the design concept of functional separation and synergy, provides a replaceable protective structure for the electrostatic deflection plate of an ion implanter that facilitates maintenance, thereby solving the above problems. This replaceable protective structure effectively protects the electrostatic deflection plate body from sputtering contamination, facilitates quick replacement and maintenance, and works in conjunction with the electrostatic deflection plate body to maintain the uniformity of the electrostatic deflection electric field distribution. Summary of the Invention

[0005] The purpose of this invention is to provide a replaceable protective structure for an electrostatic deflection plate.

[0006] The objective of this invention is achieved through the following technical solution: A replaceable protective structure for an electrostatic deflection plate includes an electrode body of the electrostatic deflection plate (hereinafter referred to as the electrode body). A slot is provided on the beam-facing surface of the electrode body, and a composite protective layer is provided in the slot. Along the beam transmission direction, the composite protective layer includes a pull-out protective layer and a conductive pad from the outside to the inside. The conductive pad is located at the bottom of the slot. The surface of the protective layer is basically flush with the beam-facing surface of the electrode body. In actual processing, due to the influence of processing tolerance, the height difference between the beam-facing surface of the protective layer and the beam-facing surface of the electrode body does not exceed 0.05 mm. A fitting gap is left between the side wall of the slot and the side wall of the protective layer and the side wall of the conductive pad. An elastic conductive track is provided on the side wall of the slot. The elastic conductive track crosses the fitting gap and contacts the side wall of the protective layer and the side wall of the conductive pad, thus acting as a bridge to connect the side wall of the protective layer and the side wall of the conductive pad with the side wall of the slot.

[0007] The thickness of the fit clearance can usually be controlled between 0.05 and 0.1 mm.

[0008] Preferably, the slot and the electrode plate body have a common central axis of symmetry along the beam propagation direction, both the slot and the electrode plate body are axisymmetric structures, the cross section of the slot along the beam propagation direction is rectangular or trapezoidal with the opening width gradually narrowing along the beam propagation direction, and the shape of the protective layer and conductive pad matches the shape of the slot.

[0009] Preferably, the length or width of the slot on the beam-facing surface of the electrode plate body accounts for 70%-86.5% of the length or width of the beam-facing surface of the electrode plate body, and the depth of the slot accounts for 5%-15% of the total length of the electrode plate body along the beam transmission direction.

[0010] Preferably, the protective layer is made of graphite or molybdenum, and the thickness h1 of the protective layer accounts for 92%-97% of the slot depth.

[0011] Preferably, the conductive pad is made of flexible graphite or conductive ceramic, and its thickness accounts for 3%-8% of the slot depth.

[0012] Preferably, the elastic conductive track includes a metal conductive track body and a metal spring piece. A rectangular groove guide rail is provided on the side wall of the slot to accommodate the elastic conductive track. The metal spring piece is located at the bottom of the rectangular groove guide rail. The metal conductive track body is inserted into the rectangular groove guide rail, with one side in contact with the metal spring piece and the other side in contact with the protective layer. The metal conductive track body and the metal spring piece are made of conductive metal material.

[0013] Preferably, at least one elastic conductive track is provided on each side wall of the slot. The initial cross-section of the metal spring has a certain curvature, with the apex of the curvature facing the side wall of the protective layer. After the metal conductive track body and the protective layer are installed into the rectangular groove guide rail of the side wall, the metal spring is basically flattened. Generally, the radial thickness t2 after the metal spring is flattened into a straight line is 0.25-0.4 mm, and the depth d1 of the fixing groove along the normal direction of the side wall of the slot is 1-1.75 mm. The metal conductive track body is made of a material that is essentially the same as the electrode plate body and has elasticity, and is treated with self-lubrication. When the electrode plate body material is oxygen-free copper, the metal conductive track body material is made of an elastic copper alloy with a resistivity of 6.10. -6 -1.5·10 -5Ω·cm; When the electrode plate body material is aluminum alloy, the metal conductive track body material is also aluminum alloy with a resistivity of 4.10 Ω·cm; -6 -7·10 -6 Ω·cm; When the electrode plate body material is stainless steel, the metal conductive track body material is elastic stainless steel with a resistivity of 5.10 Ω·cm; -5 -1·10 -4 Ω·cm; The metal spring is made of a high-elasticity alloy that has undergone self-lubrication treatment, and its coefficient of thermal expansion is matched with the electrode plate body material and the metal conductive track body material.

[0014] Preferably, it also includes a pressure block, which is used to fix the protective layer to the electrode plate body and fill the mating gap between the sidewall of the slot and the sidewall of the protective layer adjacent to the facing surface of the electrode plate body.

[0015] Preferably, the pressure block is a corner pressure block, with one side inserted into the fitting gap and the other side pressing against the protective layer. The pressure block and the protective layer are fixed to the electrode plate body using fasteners. A reserved space is left at the bottom of the corner pressure block inserted into the fitting gap to compensate for thermal expansion and contraction and machining tolerances. For example, the height of the reserved space between the bottom of the corner pressure block and the top of the rectangular groove guide rail on the side wall is generally 0.05-0.1 mm, preferably 0.05-0.08 mm. The width of the corner pressure block parallel to the slot opening can be controlled between 5-15 mm, and the depth of the corner pressure block inserted into the fitting gap along the z-direction can be controlled between 1.5-2.5 mm.

[0016] Preferably, the electrode plate body, conductive pad, elastic conductive track and protective layer together constitute an equipotential body, wherein the protective layer is equipotentially connected to the electrode plate body along the beam transmission direction through the conductive pad, and the protective layer is equipotentially connected to the electrode plate body radially through the elastic conductive track.

[0017] The specific design concept of this invention is explained as follows: 1. Slot First, the coordinate axes of the Cartesian coordinate system in this invention are given: Let the central axis of the beam envelope be the z-axis, and the beam transmission direction be the positive z-axis. Correspondingly, the radial axes of the beam transmission direction are set as the x-axis and y-axis, where the x-axis is the axis containing the beam deflection direction, and the beam deflection direction is the positive x-axis.

[0018] like Figure 2 and Figure 3As shown, the slot is a general-purpose planar open slot, positioned on the side of the electrostatic deflection plate facing the beam (referred to as the beam-facing side), thus the planar open slot faces the negative z-axis direction. The planar open slot refers to an open slot with planar sidewalls. Considering both manufacturability and ease of component replacement, the planar open slot typically has several preferred designs, including a rectangular slot (…). Figure 2 ) and trapezoidal slots ( Figure 3 Furthermore, if it is a trapezoidal slot, its opening width gradually narrows along the z-direction.

[0019] The planar open slot and the electrode plate body share a common central axis of symmetry in the z-direction, and both exhibit a matched axisymmetric structure about this central axis. Within the xoy plane at the starting position z0 where the beam enters the electrode plate body, the width of the opening of the planar open slot in the x and y directions accounts for 70%-86.5% of the total width of the electrode plate body in the corresponding directions, respectively; correspondingly, the opening area of ​​the planar open slot accounts for approximately 49%-75% of the area of ​​the contour surface enclosed by the outer edge of the electrode plate body. When the planar open slot is preferably rectangular or trapezoidal, the opening of the planar open slot is symmetrically centered about the central axis of symmetry in both the x and y directions. Based on the above conditions, the widths of the openings in the x and y directions should be independently set, with the principle of covering the main bombardment area of ​​the scattered ions on the deflection plate within the beam envelope of the instrument.

[0020] The principle for selecting the above ratio is as follows: if the ratio is too small, the exposed area of ​​the electrode plate body edge will be too large, and the area of ​​the electrode plate body subject to direct bombardment by beam edge scattered ions will be too large, resulting in insufficient protection; if the ratio is too large, the four sides of the electrode plate will be too narrow, the structural strength will be weakened, and mechanical deformation will easily occur under the action of electrostatic field, and there will be insufficient space for the arrangement of components such as fixing screw holes.

[0021] It is important to emphasize that for trapezoidal slots, because their cross-section gradually narrows along the z-direction, this alleviates the weakening of structural strength caused by increasing the opening area to increase the protective coverage area. As a result, the opening area of ​​the trapezoidal slot at z0 can take a larger value, and its upper limit of area ratio is therefore higher than that of the rectangular slot scheme under the same conditions.

[0022] The depth of the planar open slot along the beam transmission direction, i.e., the slot depth h, needs to be determined in conjunction with the range of the total length L of the electrostatic deflection plate of the ion implanter along the beam transmission direction. The value of L is typically 60-500 mm; specifically, 60-120 mm for experimental models and 150-500 mm for industrial models. Based on this, the slot depth accounts for 5%-15% of the total length of the electrode plate body along the z-direction, preferably 5%-10%. The slot depth must be chosen to comprehensively consider both adequate protection and the structural integrity of the electrode plate body; it should not be too large or too small, but appropriate. If it is too small, the effective thickness of the protective layer will be insufficient, making it easily penetrated by ion bombardment in the beam transmission direction, causing the electrode plate body in the depth direction to be prematurely exposed to ion bombardment. If it is too large, excessive material will be removed from the electrode plate body, weakening the mechanical stability of the body under the electrostatic field, which is not beneficial to improving protection performance and also increases unnecessary material and processing costs.

[0023] 2. Composite protective layer structure like Figure 2 and Figure 3 As shown, the planar open slot is equipped with a composite protective layer. Along the beam transmission direction, the composite protective layer consists of a removable protective layer and a conductive pad, from the outside in, with the conductive pad adjacent to the electrode plate body. The cross-sectional shape of the protective layer and the conductive pad in the xoy plane always matches the cross-sectional shape of the inner cavity of the planar open slot at the same z-value. The protective layer, conductive pad, planar open slot, and electrode plate body share a common central axis of symmetry in the z-direction, and they all exhibit a matched axisymmetric structure about this central axis of symmetry.

[0024] A 0.05-0.1 mm clearance is maintained between the protective layer and the conductive pad and the sidewall of the planar open slot. This clearance provides space for the flexible conductive track and compensates for thermal expansion and contraction and machining tolerances. As will be described in section 4, once the flexible conductive track is installed, this clearance is effectively bridged by the track, resulting in a tight, sufficient, continuous, narrow surface contact between the protective layer sidewall, the flexible conductive track, and the electrode plate body of the slot sidewall. This forms a radial equipotential electrical connection between the protective layer sidewall and the electrode plate body of the planar open slot sidewall.

[0025] Based on the above, when the planar open slot of the present invention is rectangular or trapezoidal, the protective layer and conductive pad inside the slot are correspondingly cuboid or trapezoidal, referred to herein as rectangular protective layer and trapezoidal protective layer, and rectangular conductive pad and trapezoidal conductive pad.

[0026] The body material of the electrostatic deflection plate in this invention can be the same metal material used in conventional integral electrostatic deflection plates, such as oxygen-free copper (resistivity: 1.7 × 10⁻⁶). -6 -2·10 -6Ω·cm), aluminum alloy (resistivity: 2.6·10 ...) -6 -5·10 -6 Ω·cm) or stainless steel (resistivity: 5.10 -5 -1·10 -4 (Ω·cm), etc. The selection of the body material is based on a comprehensive balance of factors such as conductivity, structural strength, processability, process requirements, and cost, and its resistivity is used as a reference in this invention.

[0027] The selection of the protective layer should prioritize materials that minimize wafer contamination, are sputter-resistant, have good conductivity, and are easy to process, while also considering cost. Theoretically, using materials with weak sputter resistance can compensate for this by increasing the protective layer thickness; however, this would lead to excessively deep slots and increased material removal from the substrate, weakening the integrity of the electrode plate structure. Therefore, materials with low sputtering yield or high sputtering thresholds are preferred. Simultaneously, as a crucial component of the equipotential bonding system, the protective layer must possess good conductivity to ensure a stable and reliable equipotential bond between it and the electrode plate substrate.

[0028] Based on the above, the protective layer material is usually made of graphite or molybdenum, both of which have good electrical conductivity, with graphite having a resistivity in the range of 10⁻⁶. -5 -10 -3 The resistivity of molybdenum is approximately 5.3 Ω·cm, with the specific value depending on its purity and degree of crystallization. -6 Ω·cm. Both graphite and molybdenum exhibit excellent sputtering resistance and are suitable for high-current applications. Graphite, however, has a lower sputtering yield and causes less wafer contamination; molybdenum has a higher sputtering threshold and a longer bombardment lifetime, making it more suitable for heavy ion implantation. The z-direction thickness h1 of the protective layer is typically 92%-97% of the slot depth.

[0029] The conductive pad material must possess good conductivity, flexibility, elasticity, self-lubrication, and vacuum compatibility. Its coefficient of thermal expansion should match that of the protective layer and the electrode plate body. Matching the coefficients of thermal expansion means that, within the normal operating temperature range of the electrostatic deflection plate, when the temperature rises, the increase in size along the z-direction caused by the difference in the coefficients of thermal expansion of the conductive pad, protective layer, and electrode plate body can be absorbed by the flexible deformation of the conductive pad, preventing excessive compressive stress and preventing the protective layer from bulging relative to the electrode plate body. When the temperature decreases, the difference in contraction among the three components will not cause gaps exceeding the allowable range between the conductive pad and the protective layer or electrode plate body, thus maintaining close contact and stable equipotential bonding along the z-direction. These material properties, in addition to ensuring equipotential bonding between the protective layer and the electrode plate body, also provide mechanical buffering, compensation for thermal expansion and contraction, and protection of the slot bottom surface. Therefore, flexible graphite with a resistivity range of 10⁻⁶ is typically chosen for the conductive pad. -4 -10-3 Ω·cm; or conductive ceramics with a resistivity range of 10 Ω·cm; -4 -10 -3 Ω·cm. The thickness h2 of the conductive pad in the z-direction is typically 3%-8% of the slot depth.

[0030] The conductive pad is structurally designed to ensure a good and reliable electrical connection between the protective layer and the electrode plate body in the z-direction, and is the core component for achieving equipotential connection between the two.

[0031] It is important to emphasize that the design goal is for the slot depth to be equal to the sum of the thicknesses of the protective layer and the conductive pad in the z-direction, i.e., h = h1 + h2. The main purpose is to ensure that the surface of the assembled protective layer is flush with the facing surface of the electrode plate. Although the protective layer and the electrode plate are connected at the same potential through the conductive pad, if the surface of the protective layer is raised or recessed, it will introduce a geometric step on the equipotential surface of the facing surface of the electrostatic deflection plate, which will then generate local electric field distortion near the step. Therefore, this flush design aims to eliminate this geometric discontinuity to minimize the impact on the distribution of the electrostatic deflection electric field. In actual manufacturing, due to manufacturing tolerances, the height difference between the facing surface of the protective layer and the facing surface of the electrode plate does not exceed 0.05 mm.

[0032] 3. Implement specific protective structures suitable for assembling and replacing components. Based on the macroscopic structure described in 1 to 3, and taking into account the assemblability of each component, the ease of replacement of replaceable components, and the mechanical and electrical reliability in actual use, the macroscopic replaceable protective structure needs to be realized through the following specific structural design.

[0033] 1) The composite protective layer inside the planar open slot is fixed and replaceable by means of pressure blocks, fasteners, and elastic conductive rails. like Figures 2-5 As shown, a clamping mechanism using a pressure block and fasteners is employed to mechanically fix the replaceable protective layer and conductive pad within the flat open slot to the electrode plate body.

[0034] like Figure 2 and Figure 3As shown, conductive pads and a protective layer are sequentially placed within a planar open slot along the beam transmission direction, with the conductive pads and electrode plate bodies adjacent to each other. To achieve both radial electrical contact and smooth pull-out between the protective layer sidewall and the slot sidewall, an elastic conductive track is provided on the slot sidewall. This elastic conductive track extends along the sidewall of the planar open slot and is fixed to the slot sidewall. A 0.05-0.1 mm clearance is maintained between the sidewalls of the protective layer and conductive pad and the slot sidewall to compensate for thermal expansion and contraction and machining tolerances. Simultaneously, the elastic conductive track on the slot sidewall is also located within this clearance, achieving, after assembly, a fully continuous elastic narrow-surface contact between the protective layer sidewall, the elastic conductive track, and the electrode plate body on the slot sidewall; thus, while forming a good and reliable radial equipotential connection, good and stable pull-out performance along the z-direction is also obtained.

[0035] The pressure blocks are arranged around the perimeter of the open slot opening. While pressing against the edges of the protective layer's facing surface, they also fill the mating gaps between the protective layer sidewall and the slot sidewall adjacent to the facing surface. This is to prevent bombardment and sputtering particles from entering the mating gaps and to maintain a clean working environment for the internal elastic conductive tracks, preventing particle deposition from affecting their long-term operational stability. To meet this requirement, the pressure blocks extend continuously along the edges of the protective layer, and are angled along the facing surface and the protective layer sidewall (referred to as corner pressure blocks). The angle of the corner is consistent with the angle of the open slot. One side of the corner presses against the edges of the protective layer's facing surface, while the other side is inserted into the mating gap to fill it. Generally, the width of the corner pressure block parallel to the slot opening is 5-15 mm, and the depth of the corner pressure block inserted into the mating gap along the z-direction is 1.5-2.5 mm. The material of the corner pressure block is consistent with the electrode plate body material, ensuring good conductivity while avoiding thermal expansion and contraction mismatch.

[0036] The corner clamping block requires fasteners for securing it. The fasteners are preferably countersunk hexagonal screws, made of the same material as the electrode plate body. Typically, n (n≥2) countersunk hexagonal screws are used at even intervals along each edge of the protective layer to secure the corner clamping block, achieving a more uniform clamping force. For rectangular slots, the head of the countersunk hexagonal screw presses against the surface of the corner clamping block, passes through the pre-drilled holes in the corner clamping block, the edge areas of the protective layer, and the corresponding pre-drilled holes in the conductive pad along the z-direction, and is then secured to the electrode plate body at the bottom of the slot. The other side of the corner clamping block is inserted into the fitting gap to fill it completely. For trapezoidal slots, the head of the countersunk hexagonal screw presses against the surface of the clamping block, passes through the pre-drilled holes in the clamping block and the edge areas of the protective layer along the z-direction, crosses the fitting gap, and is secured to the electrode plate body on the side wall of the slot. During this process, the screw does not pass through the conductive pad, and the other side of the corner clamping block is inserted into the fitting gap to fill it completely. It is important to emphasize that for trapezoidal slots, the socket head cap screws should be fixed on the side wall of the body outside the area covered by the elastic conductive track, to ensure that the screws do not come into contact with or are too close to the elastic conductive track.

[0037] When the screws are tightened, the preload is transmitted through the corner clamping blocks to the edges of the protective layer's facing surface, pressing the protective layer and conductive pad tightly against the bottom of the slot, thus achieving mechanical fixation, electrical connection, and anti-dislodgement in the z-direction. After the corner clamping blocks are locked, the elastic conductive track maintains elastic contact with the sidewalls of the protective layer and conductive pad, thereby establishing a radial electrical connection. In summary, the protective layer, conductive pad, and electrode plate body achieve a tight fixation and electrical connection through the mechanical clamping force of the corner clamping blocks and the elastic contact force of the elastic conductive track, while also ensuring good pull-out performance of the protective layer and conductive pad.

[0038] It is important to emphasize that after assembly, the corner clamp will slightly protrude from the electrode plate body and protective layer on the beam-facing surface, introducing localized, static geometric discontinuities. Since the corner clamp and the countersunk hexagonal screws are at the same potential as the electrode plate body, this discontinuity only produces a very small and controllable local electric field distortion. Based on this, the z-axis depth of the corner clamp can be controlled between 1.5-2.5 mm. Considering the small height difference (≤0.05 mm) between the protective layer and the beam-facing surface of the electrode plate body due to machining tolerances, the actual additional micro-protrusion may be even smaller. After tightening, the screw head of the countersunk hexagonal screw is flush with the surface of the corner clamp, without introducing any additional geometric steps. Compared to the irreversible and continuously deteriorating dynamic electric field distortion caused by sputter contamination from ion bombardment, this design replaces the much larger and continuously accumulating dynamic electric field distortion with a very small and controllable static electric field distortion, representing a reasonable engineering trade-off.

[0039] The facing surface of the electrode plate body is the pull-out opening, so there is no need to open it separately on the x- or y-direction end face.

[0040] 2) Elastic conductive track like Figure 7 As shown, the elastic conductive track set on the side wall of the planar open slot consists of three parts: a metal conductive track body, a metal spring, and a fixing structure.

[0041] The metal conductive track body is a strip-shaped metal body with good elasticity that extends along the side wall of the planar open slot.

[0042] The metal spring is a strip-shaped metal sheet with excellent elasticity, positioned between the metal conductive track body and the fixed structure of the planar open slot sidewall. It extends along the z-axis, and its initial cross-section is an arc with a certain curvature along the radial direction (perpendicular to the z-axis), with the apex of the arc facing the protective layer sidewall. Figure 7 As shown. Generally, the radial thickness t2 of the metal spring after being flattened into a straight line is 0.25-0.4 mm. The elastic force of the metal spring points towards the sidewall of the protective layer, providing a continuous radial preload to the metal conductive track body, keeping the metal conductive track body pressed tightly against the sidewall of the protective layer, forming a tight, sufficient, elastic, continuous, narrow surface contact; the metal spring also compensates for thermal expansion and contraction and machining tolerances.

[0043] The metal conductive track body and the metal spring can be fixed by machining corresponding fixing structures on the side wall of the slot, generally using a fixing slot. A rectangular slot guide is preferred, hereinafter referred to as the side-wall rectangular slot guide, to distinguish it from the rectangular slot on the facing surface mentioned earlier. Generally, the depth d1 of the side-wall rectangular slot guide along the normal direction of the side wall of the open slot is 1-1.75 mm.

[0044] At least one elastic conductive track is provided on each sidewall around the protective layer, and there are usually two or three. Each elastic conductive track consists of a metal conductive track body, a metal spring piece, and a rectangular groove guide rail on the sidewall. The shapes and volumes of the three parts are adapted to each other to ensure that the metal conductive track body and the metal spring piece can be firmly installed in the rectangular groove guide rail on the sidewall.

[0045] In terms of manufacturing, the sidewall rectangular groove guide rail is formed by milling rectangular grooves into the sidewall of the open planar slot. The metal spring is preferably stamped, and the metal conductive track body is CNC milled. During installation, the metal spring is first placed directly on the bottom surface of the sidewall rectangular groove guide rail, allowing it to slide freely; then, the metal conductive track body is inserted into the sidewall rectangular groove guide rail, ensuring that the metal conductive track body is tightly fitted to the metal spring, thus completing the installation of the elastic conductive track on the sidewall of the open planar slot. All of the above manufacturing and installation are completed within the confined space of the open planar slot. The CNC milling and stamping processes involved are conventional technologies already existing in the field, requiring guaranteed precision in the fit between the various parts and good engineering feasibility.

[0046] The rectangular groove guide rail extends along the sidewall of the open planar slot and adjoins the electrode plate body at the bottom of the open planar slot. Considering thermal expansion and contraction compensation and machining tolerances, a certain gap is reserved between the top of the rectangular groove guide rail along the sidewall of the open planar slot and the bottom of the corner pressure block within the fitting clearance, typically 0.05-0.1 mm, preferably 0.05-0.08 mm. While minimizing machining tolerances, the lengths of both the metal conductive track body and the flattened metal spring sheet along the sidewall of the open planar slot are equal to the length L of the rectangular groove guide rail along the sidewall of the open planar slot. t This is the design goal of achieving full, stable, and continuous narrow surface contact in the radial direction. Because the metal spring sheet has excellent elasticity, and the metal conductive track body also possesses good elasticity, it can effectively compensate for minor deviations caused by thermal expansion and contraction.

[0047] Let d1 be the depth of the rectangular groove guide rail along the normal direction of the open-face slot sidewall, d2 be the fit clearance between the open-face slot sidewall and the protective layer and conductive pad sidewall, t2 be the radial thickness of the metal spring sheet after being flattened into a straight line, and t1 be the radial thickness of the metal conductive track body. To ensure sufficient contact under any working condition, the design target is that t1 + t2 is slightly greater than d1 + d2. Generally, d1 is taken as 1-1.75 mm, t2 is taken as 0.25-0.4 mm, and d2 is given as 0.05-0.1 mm above. From this, the value of t1 can be determined. For example, if d1 = 1.25 mm, d2 = 0.07 mm, and t2 = 0.35 mm, then t1 should be slightly greater than 0.97 mm, and can be taken as 0.99 mm. Under this numerical relationship, the majority of the radial thickness of the metal conductive track body lies within the rectangular groove guide rail on the sidewall. Therefore, the rectangular groove guide rail provides excellent fixation along the sidewall of the planar open slot. The metal spring provides elastic support and radial preload at the radial bottom of the rectangular groove to compensate for minor radial displacement caused by thermal expansion and contraction. Specifically, due to the excellent elasticity of the metal spring, it can act as the core of elastic compensation: during thermal expansion, it can be further compressed to absorb the expansion, effectively preventing damage from mutual compression between different parts of the overall elastic conductive track structure; during cold contraction, its own rebound force can compensate for the minor shrinkage of each component, still ensuring sufficient and stable radial contact. The metal conductive track body and the metal spring work together to ensure long-term stable and reliable radial electrical contact.

[0048] The metal conductive track body material must possess good conductivity, elasticity, self-lubrication, compatibility with the thermal expansion coefficient of the electrode plate body material, fatigue resistance, wear resistance, no risk of cold welding, and vacuum compatibility. Typically, a material of the same or similar nature as the electrode plate body material can be selected, and self-lubricating treatment is applied. Specifically, when the electrode plate body material is oxygen-free copper, the preferred metal conductive track body material is an elastic copper alloy with a resistivity of 6.10. -6 -1.5·10 -5 Ω·cm; When the electrode plate body material is aluminum alloy, the preferred material for the metal conductive track body is an aluminum alloy of the same material as the body, with excellent elasticity and a resistivity of 4.10 Ω·cm. -6 -7·10 -6 Ω·cm; When the electrode plate body material is stainless steel, the preferred material for the metal conductive track body is stainless steel with excellent elasticity and a resistivity of 5.10 Ω·cm; -5 -1·10 -4 Ω·cm.

[0049] The metal spring material must possess excellent elasticity, good electrical conductivity, and self-lubricating properties, while also exhibiting fatigue resistance, no risk of cold welding, and vacuum compatibility. Its coefficient of thermal expansion must match that of the track body and electrode plate body materials. Typically, highly elastic alloys treated with self-lubrication, such as beryllium copper, highly elastic aluminum alloys, and spring steel, can be selected.

[0050] The matching of thermal expansion coefficients of the aforementioned metal conductive track body, metal spring sheet and electrode plate body refers to the fact that within the normal operating temperature range of the electrostatic deflection plate, the dimensional changes in the radial and z directions caused by the difference in thermal expansion coefficients of each component can be compensated by the fitting clearance and elastic deformation of the metal spring sheet, as well as the rectangular groove guide rail on the side wall, so as not to generate excessive stress or poor contact, thereby maintaining structural stability, installation stability and radial equipotential connection stability and reliability.

[0051] Based on the design, material selection, processing, and installation of each component of the elastic conductive track described above, the elastic conductive track, as a whole component, possesses a stable and reliable working structure, as well as good installability and disassembly. The working principle of the elastic conductive track and its role in the replaceable protective structure of the electrostatic deflection plate are as follows.

[0052] (1) such as Figure 6As shown, utilizing the excellent elasticity of the metal spring, the initially curved metal spring is flattened into a straight line during the installation of the conductive pad and protective layer, allowing the metal spring and the metal conductive track body to naturally and fully engage with the rectangular slot guide rail on the side wall. Simultaneously, within the mating gap, the radial side of the metal conductive track body fully presses against the side wall of the protective layer and conductive pad, ensuring a sufficiently tight elastic contact between the side wall of the protective layer and conductive pad, the metal conductive track body, the metal spring, and the electrode plate body of the planar open slot side wall. This forms a tight, sufficient, continuous, narrow surface contact, capable of accommodating minor displacements that may occur due to thermal expansion and contraction under environmental temperature changes. Furthermore, the elastic conductive track employs a multi-track parallel design, providing mutual redundancy under normal conditions; however, if the radial electrical connection of one track is compromised for various reasons, the remaining tracks can still independently ensure a good radial equipotential connection. Therefore, a good and reliable radial equipotential electrical connection can be formed between the side wall of the protective layer and the electrode plate body of the slot side wall.

[0053] (2) The metal conductive track body is also the pull-out track for the protective layer and conductive pad. Since both the metal spring and the metal conductive track body have good lubrication properties, the friction between the sub-components is low, the pull-out and sliding are smooth, and the elastic deformation of the metal spring is not hindered. Therefore, the elastic conductive track has good pull-out and wear resistance, which can ensure good installation and replaceability.

[0054] 3) Equipotential bonding Based on the above structure, the equipotential connection between the protective layer and the electrode plate body consists of two paths: a conductive pad provides a large-area close contact in the z-direction, serving as the main path; and a multi-track parallel design of elastic conductive tracks provides a tight, sufficient, continuous, narrow surface contact in the radial direction, becoming an auxiliary path with redundancy. The main path and the auxiliary path are connected in parallel, cooperating and redundant with each other to ensure the interference resistance and long-term reliability of the equipotential connection.

[0055] It should be noted that the equipotential connection between the replaceable protective structure and the electrode plate body provided in this invention follows the basic principle of a series circuit: the voltage drop in a series circuit depends on the component with the largest resistance value; when the volume resistance or contact resistance components in the components are very small, the voltage drop corresponding to these resistance components is also very small. Specifically, on the one hand, each component in the composite protective layer (i.e., the protective layer, conductive pad, elastic conductive track, corner clamp, and internal hexagon countersunk screw) is a good conductor of electricity, so they do not affect the equipotential connection. On the other hand, the large-area contact between the corner clamp, protective layer, conductive pad, and electrode plate body, as well as the continuous narrow surface contact between the electrode plate body, elastic conductive track, and protective layer sidewall on the slot sidewall, all have extremely small and stable contact resistance, which also ensures a good and stable equipotential connection. Therefore, as long as the materials of each component in the composite protective layer are selected with the good conductivity given above, a good, stable, and long-term reliable equipotential connection can be achieved, thereby ensuring the uniformity and long-term stability of the electrostatic deflection field.

[0056] 4) Other optional mechanical fixing methods Besides the aforementioned fixing method using pressure blocks and fasteners, other mechanical solutions can also be used to fix and connect the composite protective layer within the planar open slot to the electrode plate body, such as dovetail grooves, triangular grooves, T-grooves, or keyways. Different fixing and connection methods will result in corresponding minor adjustments to the specific structure of the planar open slot and the composite protective layer, which will not be elaborated here, but all remain within the scope of the invention's main inventive concept and are still protected by this invention.

[0057] 4. Installation and Replacement Based on the aforementioned structural description, the installation and replacement schemes for the protective layer, conductive pads, and elastic conductive rails are as follows.

[0058] 4.1 General Installation Requirements During assembly, such as Figure 6 and Figure 7As shown, firstly, the metal spring is placed directly on the bottom surface of the rectangular groove guide rail on the side wall, allowing it to slide freely. Then, the metal conductive track body is inserted into the rectangular groove guide rail, ensuring it is flush against the metal spring. Next, the conductive pad and protective layer are placed sequentially into the slot. During this process, the side walls of the conductive pad and protective layer slide along the elastic conductive track until the conductive pad reaches the bottom surface of the open slot and contacts the electrode plate body, followed by the protective layer. When the protective layer is pushed into place, the initially curved metal spring is flattened into a straight line, allowing the metal spring and the metal conductive track body to naturally and fully engage with the rectangular groove guide rail on the side wall, forming a tight and continuous narrow surface contact with the side walls of the protective layer and conductive pad, as well as with the side wall of the slot. Finally, using a corner clamp and countersunk hexagonal screws, the protective layer and conductive pad are pressed and fixed along the z-direction, with the other side of the corner clamp inserted into the gap to fill it completely.

[0059] After assembly, the protective layer, conductive pad, and electrode plate body are mechanically clamped together, achieving stable mechanical fixation, preventing detachment, and ensuring electrical connection in the z-direction. The sidewalls of the protective layer and conductive pad, and the sidewalls of the electrode plate body in the planar open slot, are connected by elastic conductive tracks, achieving continuous radial contact and radial electrical connection. The height difference between the facing surface of the protective layer and the facing surface of the electrode plate body does not exceed 0.05 mm to minimize the impact on the distribution of the electrostatic deflection field.

[0060] 4.2 Replacement Operation The protective layer, conductive pads, and flexible conductive tracks are all independent, replaceable components. Among them, the flexible conductive tracks are replaced the least frequently, followed by the conductive pads; while the protective layer, as a sacrificial layer to resist sputtering, is replaced the most frequently.

[0061] like Figures 2-5 As shown, when replacing the above components, after loosening the hexagon countersunk screws and removing the corner clamps, the protective layer and conductive pad can be pulled out along the elastic conductive track. When the elastic conductive track is damaged or its elasticity is diminished, it needs to be replaced. The old track (including the metal spring and the metal conductive track body) can be pulled out from the rectangular groove guide rail on the side wall, and then the new track can be installed. The steps and standards for installing new elastic conductive tracks, conductive pads, and protective layers are the same as in 4.1. Therefore, it can be seen that the replacement of these components is very convenient.

[0062] Since the corner clamping block has the function of filling and compacting the mating gap between the protective layer sidewall and the planar open slot sidewall near the beam-facing surface, it also undertakes a certain anti-splashing responsibility. Therefore, the corner clamping block also needs to be replaced regularly, with a replacement frequency lower than that of the protective layer but higher than that of the conductive pad.

[0063] It is important to emphasize that, since the countersunk hexagonal screws are installed last and removed first, this assembly and disassembly sequence ensures that the trapezoidal slot does not interfere with the track during operation.

[0064] 5. Furthermore, the charged particles applicable to this invention can be ions formed from any element, including positive or negative ions, as well as atomic or molecular ions. The design and technical implementation scheme have no special limitations on the mass, charge state, and element type of the charged particles, and are therefore universally applicable. The design of this invention can effectively resist physical sputtering, chemical sputtering, and reactive sputtering etching of the electrostatic deflection plate caused by the aforementioned charged particles.

[0065] 6. Furthermore, the replaceable protective structure of the electrostatic deflector provided by the present invention is suitable for ion implanters, and is also suitable for electrostatic deflectors in other charged particle beam transmission and control equipment such as accelerators, mass spectrometers, and isotope separators.

[0066] The beneficial effects of this invention are: 1) This invention is based on the design concept of functional separation and synergy. A planar open slot is provided on the beam-facing surface of the electrostatic deflection plate. Based on this, the electrostatic deflection plate is divided into a flexibly replaceable composite protective layer and the original integral electrode plate body. The composite protective layer consists of a protective layer and conductive pads, and an elastic conductive track is provided to synergistically achieve the flexible replaceability of the composite protective layer. Furthermore, the elastic conductive track itself also embodies the design concept of functional separation and synergy: the metal conductive track body focuses on radial electrical connection, while the metal spring focuses on providing elastic preload. Together, they achieve long-term stable and reliable radial contact and the flexible replaceability of the composite protective layer.

[0067] The equipotential connection between the protective layer and the electrode plate body consists of two paths: a conductive pad provides a large-area, tight contact in the beam transmission direction, serving as the main path; and a multi-track parallel design of elastic conductive tracks provides a tight, sufficient, continuous, narrow surface contact in the radial direction, becoming an auxiliary path with redundancy. The parallel connection of the main and auxiliary paths, their mutual cooperation and redundancy, ensure that the electrode plate body, conductive pad, elastic conductive tracks, and protective layer together constitute a complete equipotential body, guaranteeing the interference resistance and long-term reliability of the equipotential connection. Based on the above, the electrostatic deflection plate with a replaceable protective structure of this invention exhibits the same basic electrostatic deflection scanning performance as traditional integral electrostatic deflection plates.

[0068] In the composite protective layer, the protective layer acts as a sacrificial layer, absorbing the majority of the bombardment from scattered ions and sputtering products. Within its coverage area, it replaces the original electrode plate surface in bearing most of the sputtering and contamination, maintaining the original machining accuracy of the plate. Furthermore, the corner clamping block fills the gap between the protective layer sidewall and the slot sidewall near the beam-facing surface. This prevents bombardment and sputtering particles from entering the gap and maintains a clean working environment for the internal elastic conductive track, avoiding particle deposition that could affect the long-term stability of the internal elastic conductive track. Based on the above, the composite protective layer structure presented in this invention exhibits excellent anti-sputtering performance. When the protective layer and corner clamping block suffer morphological degradation or performance failure due to long-term sputtering, the beam-facing surface condition can be restored by periodically replacing the protective layer, corner clamping block, and conductive pads. This effectively suppresses the accumulation of electrostatic deflection field distortion and ensures that the uniformity of the electrostatic deflection field remains stable at its initial level over the long term.

[0069] 2) For the composite protective layer of the electrostatic deflection plate, the protective layer and the electrode plate body achieve a stable and reliable dual-path equipotential connection through conductive pads and elastic conductive tracks, ensuring that the entire beam-facing surface is at the same potential. The protective layer itself has a low sputtering yield or a high sputtering threshold, resulting in slow formation of contamination and damage layers. Moreover, as a consumable component, the protective layer is replaced periodically, eliminating contamination and damage layers before they accumulate to form a stable charge accumulation area. Based on the above, these measures can fundamentally eliminate the conditions for micro-discharge formation, thereby preventing arc erosion damage to the electrode surface and preventing micro-discharge breakdown of the electrode surface. Therefore, the composite protective layer can effectively solve the micro-discharge and breakdown problems of traditional integral electrodes, especially under conditions such as high beam current, heavy ion implantation, strong deflection electric field, and long-term operation.

[0070] 3) The conductive pads between the protective layer and the electrode plate body not only achieve equipotential bonding but also serve multiple functions such as mechanical buffering, compensating for thermal expansion and contraction, and protecting the bottom surface of the slot, ensuring the long-term reliability of the composite protective structure from both mechanical and thermal perspectives. The metal conductive track body also serves as the pull-out track for the protective layer and conductive pads, possessing excellent pull-out and wear-resistant properties, ensuring good installability and replaceability.

[0071] 4) The protective layer, corner clamps, conductive pads, and flexible conductive tracks (including metal springs and the metal conductive track body) are all independently replaceable components. The protective layer and corner clamps, being directly subjected to sputtering, need to be replaced promptly based on the sputtering damage or surface contamination status. The conductive pads and flexible conductive tracks, due to their protected working environment, can be replaced primarily based on their material condition, with more flexible replacement cycles. Replacing these components simply requires loosening the hexagonal countersunk screws and corner clamps, removing the old part, replacing it with the new one, and re-tightening. The flexible conductive tracks can also be easily replaced via the rectangular groove guide rail on the side wall. Therefore, the replacement operation for each component is simple and quick. Each component can be replaced individually based on its actual wear condition or during routine equipment maintenance (PM), offering flexible replacement options. Therefore, this effectively improves the equipment utilization rate of the electrostatic deflection plate.

[0072] 5) While regular offline chemical cleaning can temporarily alleviate the problem of sputter contamination on the electrodes of traditional integral electrostatic deflection plates, repeated chemical cleaning will damage the surface precision of the electrodes, leading to deterioration of surface roughness and degradation of electric field uniformity, thus causing a gradual decrease in electrode performance. If not cleaned in time, the overall electrode plate material performance will gradually deteriorate until it fails.

[0073] This invention separates the electrostatic deflection plate into a replaceable composite protective layer and the original integral electrode plate body. During use, only the composite protective layer and spare parts such as the elastic conductive track need to be replaced periodically. Under the effective protection of the composite protective layer, the sputtering and contamination experienced by the electrode plate body are significantly reduced, especially in the depth direction where the electrode plate body is protected from sputtering. Therefore, the electrode plate body provided by this invention can serve stably for a long period, effectively reducing the overall lifecycle cost.

[0074] 6) The protective layer in the composite shielding layer uses graphite or molybdenum, which have excellent sputtering resistance. Graphite has a low sputtering yield and causes less wafer contamination, while molybdenum has a higher sputtering threshold. Therefore, the replaceable shielding structure can effectively reduce sputtering contamination (especially metal particles) of the charged particle beam on the electrostatic deflector plate, thereby effectively mitigating the impact of sputtering contamination on the vacuum chamber walls, downstream beam elements, and wafer surface. This also improves beam performance and semiconductor chip yield, and this beneficial effect is even more pronounced under conditions such as high beam current and heavy ion implantation.

[0075] 7) The design and technical implementation method of the replaceable protective structure of the electrostatic deflection plate of the present invention are simple, easy to process and manufacture, low in cost, and suitable for industrial promotion and application. Attached Figure Description

[0076] Figure 1A schematic diagram of a commonly used integral electrostatic deflection plate. In this diagram, 1 is the positive plate, 2 is the negative plate, 11 represents a charged particle, and 12 indicates the beam propagation direction of the charged particles.

[0077] Figure 2 This invention presents a cross-sectional view of the electrostatic deflection plate with a replaceable protective structure along the xoz plane (cut along the y-axis center plane), showing the rectangular slot configuration. Specifically, 1 is the positive electrode plate body, including the positive electrode plate body surrounding the rectangular slot; 2 is the negative electrode plate body, including the negative electrode plate body surrounding the rectangular slot; 3 is the rectangular slot; 4 is the rectangular protective layer; 5 is the rectangular conductive pad; 6 is the corner pressure block; 7 is the elastic conductive track, including a metal conductive track body, a metal spring, and a sidewall rectangular slot guide rail; 8 is a countersunk hexagonal screw; 9 is a very small gap (see enlarged view) between the top of the sidewall rectangular slot guide rail along the z-direction and the bottom of the corner pressure block along the z-direction within the mating gap; 12 represents the beam transmission direction, designated as the positive z-axis. Furthermore, a Cartesian coordinate system is also given in the lower left corner of the figure, with the x-axis and y-axis being the radial axes of the beam transmission direction, and the beam deflection direction being the positive x-axis direction. As shown in the figure, the designs of the positive and negative plates are the same for 3, 4, 5, 6, 7 and 8.

[0078] Figure 3 This invention presents a cross-sectional view of the electrostatic deflection plate with a replaceable protective structure along the xoz plane (cut along the y-axis center plane), showing the trapezoidal slot configuration. In this diagram, 1 is the positive electrode plate body, including the positive electrode plate body surrounding the trapezoidal slot; 2 is the negative electrode plate body, including the negative electrode plate body surrounding the trapezoidal slot; 3 is the trapezoidal slot; 4 is the trapezoidal protective layer; 5 is the trapezoidal conductive pad; 6 is the corner pressure block; 7 is the elastic conductive track, including a metal conductive track body, a metal spring, and a rectangular groove guide rail on the side wall; 8 is a countersunk hexagonal screw; 9 is a very small gap (see enlarged view) between the top of the rectangular groove guide rail along the side wall of the trapezoidal slot and the bottom of the corner pressure block within the mating gap; 12 indicates the beam transmission direction, designated as the positive z-axis direction. The Cartesian coordinate system in this figure is... Figure 2 The designs are identical. As shown in the figure, the designs for the positive and negative plates are the same for 3, 4, 5, 6, 7, and 8.

[0079] Figure 4This invention presents a schematic cross-sectional view (cut along the beam-facing surface) of a planar open slot for an electrostatic deflection plate with a replaceable protective structure, using one electrode as an example in a rectangular slot configuration. To clearly illustrate the internal structure, corner blocks and countersunk hexagonal screws are omitted from the figure. Wherein, 1 is the electrode plate body, which can be either a positive or negative electrode; 02 is the outer contour line of the beam-facing surface of the rectangular slot; 03 is the outer contour line of the beam-facing surface of the rectangular protective layer; 7 is an elastic conductive track, including a metal conductive track body, a metal spring, and a rectangular groove guide rail on the side wall; 10 is the fitting gap between the side wall of the rectangular slot and the side wall of the rectangular protective layer and the rectangular conductive pad. The figure also shows a Cartesian coordinate system, with the x-axis and y-axis being the radial axes of the beam transmission direction, and the beam deflection direction being the positive x-axis direction.

[0080] Figure 5 This invention relates to an electrostatic deflection plate with a replaceable protective structure. A cross-sectional view of the yoz plane at the mating gap between the sidewall of the planar open slot and the sidewalls of the protective layer and conductive pad is shown (cut at the mating gap along the x-axis, viewed towards the slot sidewall). The figure uses one electrode plate from a rectangular slot as an example (a trapezoidal slot is similar). Wherein, 001 is the sidewall of the electrode plate body; 6 is the corner clamping block; 70 is the rectangular groove guide rail of the sidewall; 007 is the metal conductive track body (the metal spring is located on its back and is obscured in the figure). It should be noted that the outer contour of the rectangular groove guide rail of the sidewall is intentionally enlarged to clearly distinguish the sub-components in the figure; in actual design, the dimensions of the metal conductive track body, the metal spring, and the rectangular groove guide rail of the sidewall should be consistent. This figure uses a scheme where the sidewall of the electrode plate body of the rectangular slot has two elastic conductive tracks as an example. The figure also shows a Cartesian coordinate system, with the x-axis and y-axis being the radial axes of the beam transmission direction, and the beam deflection direction being the positive x-axis direction.

[0081] Figure 6This invention presents a cross-sectional view of the electrostatic deflection plate with a replaceable protective structure on the xoz plane (cut along the center line of the rectangular groove guide rail on the side wall, with the viewing direction along the y-axis towards the open slot side wall of the plane), taking one electrode as an example, in the case of a rectangular slot. Wherein, 1 is the positive electrode plate body (which can also be the negative electrode), including the positive electrode plate body around the rectangular slot and the bottom of the rectangular slot in the z-direction; 001 is the side wall of the positive electrode plate body; 3 is the rectangular slot, specifically showing the bottom of the rectangular slot along the z-direction in the figure; 4 is the rectangular protective layer; 5 is the rectangular conductive pad; 6 is the corner pressure block; 70 is the rectangular groove guide rail on the side wall; 700 is the metal spring; 007 is the metal conductive track body; 8 is the internal hexagon countersunk screw; 9 is the small gap reserved between the top of the rectangular groove guide rail on the side wall along the rectangular slot side wall direction and the bottom of the corner pressure block within the fitting gap. The figure also shows a Cartesian coordinate system, with the x-axis and y-axis being the radial axes of the beam transmission direction, and the beam deflection direction being the positive x-axis direction. To more clearly show and distinguish the various sub-components in the figure, only a portion of the rectangular slot 3, rectangular protective layer 4, and rectangular conductive pad 5 are shown.

[0082] Figure 7 The diagram shows the state of the elastic conductive track without the conductive pad and protective layer installed. A cross-sectional view of the xoz plane (cut along the centerline of the rectangular groove guide rail on the sidewall, viewed along the y-axis towards the open slot sidewall) is shown, with one electrode as an example in the rectangular slot configuration. Here, 1 is the positive electrode plate body (which could also be the negative electrode), including the area around the rectangular slot and the bottom of the rectangular slot in the z-direction; 001 is the sidewall of the positive electrode plate body; 3 is the rectangular slot, more specifically, the bottom of the rectangular slot along the z-direction; 70 is the sidewall rectangular groove guide rail; 700 is the metal spring; and 007 is the metal conductive track body. A Cartesian coordinate system is also shown in the figure, with the x-axis and y-axis being the radial axes of the beam transmission direction, and the beam deflection direction being the positive x-axis direction. To more clearly illustrate and differentiate the various sub-components in the figure, only a portion of the rectangular slot 3 is shown.

[0083] It should be noted that the accompanying drawings of this invention are mainly used to schematically illustrate the structural positional relationships and connection methods between the various components. For ease of identification, the dimensional proportions of some sub-components in the views have been appropriately adjusted. The specific dimensions, thicknesses, and relative proportions of each component in the actual product can be reasonably determined by those skilled in the art based on actual design requirements and electrical performance requirements, and are not limited to the proportions shown in the accompanying drawings. Detailed Implementation

[0084] 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 them. 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.

[0085] Example 1: Replaceable protective structure for electrostatic deflection plates used in low-energy, high-current boron ion implantation. 1. Application Background and Ion Beam Parameters This embodiment utilizes low-energy, high-current boron ion implantation for the fabrication of ultra-shallow P-type doped junctions in the source and drain regions of PMOS transistors in silicon-based CMOS integrated circuit chips. Specifically, the implantation energy is 5 keV, and the implantation dose is 5.10 keV. 15 cm -2 The beam current intensity is 5 mA.

[0086] First, boron ions (in monovalent boron ions B) are generated using an ion source. + (For example) After that, B is accelerated-decelerated by the acceleration-deceleration electrode. + The ion kinetic energy is controlled to 5 keV. Then, a magnetic field analyzer is used to analyze and screen the charge-to-mass ratio. During the entire beam transmission process, a necessary quadrupole lens is used to focus the beam laterally. Finally, a pair of electrostatic deflection plates are used to scan and deflect the beam in the X and Y directions. Finally, ion implantation is performed on the silicon wafer.

[0087] B before reaching the electrostatic deflection plate + The beam current intensity is 5 mA and the kinetic energy is 5 keV. Therefore, this operating condition exhibits a strong space charge effect, significant lateral beam divergence, and continuous bombardment of the electrode plate's frontal surface by ions at the beam envelope edge. The strong beam current results in an extremely high absolute flux of scattered ions, leading to a significant cumulative physical sputtering effect. The deposition of scattered ions and self-sputtering products on the electrode plate surface forms a boron-metal mixed contamination layer, causing electric field distortion, micro-discharge, and breakdown, affecting ion scanning uniformity and the doping precision of the ultra-shallow junction.

[0088] 2. Geometric design and technical implementation of replaceable protective structure for electrostatic deflection plates. To address the aforementioned operating conditions, the replaceable protective structure described in this invention is employed in the electrostatic deflection plates of the ion implanter to solve the above problems. A pair of electrostatic deflection plates are used to scan and deflect the beam in the X and Y directions respectively. The replaceable protective structure is used for both the X and Y direction electrostatic deflection plates, and is applied to both the positive and negative electrodes of the electrostatic deflection plates. Here, only the specific technical solution for the positive electrode of the X-direction electrostatic deflection plate is given; the others are similar.

[0089] 2.1 Overview of the Replaceable Protective Structure Design for Electrostatic Deflection Plates like Figure 2 , Figure 4-7 As shown, the replaceable protective structure of the electrostatic deflection plate in the X direction of the ion implanter includes a positive electrode plate body 1, a negative electrode plate body 2, a rectangular slot 3 formed on the beam-facing surface of the electrode plate body, and a composite protective layer disposed within the rectangular slot 3. Along the beam transmission direction, the composite protective layer structure includes, from the outside to the inside, a retractable rectangular protective layer 4 and a rectangular conductive pad 5.

[0090] A fitting gap 10 is provided between the sidewall of the rectangular slot 3 and the sidewalls of the rectangular protective layer 4 and the rectangular conductive pad 5. An elastic conductive track 7, disposed on the sidewall of the rectangular slot 3, is also located within the fitting gap 10. The elastic conductive track 7 spans the fitting gap 10 and contacts the sidewalls of the rectangular protective layer 4 and the rectangular conductive pad 5. The elastic conductive track 7 includes a sidewall rectangular groove guide rail 70, a metal spring 700, and a metal conductive track body 007.

[0091] The corner pressure block 6 is arranged around the perimeter of the facing surface of the rectangular slot 3. While pressing against the edges of the facing surface of the rectangular protective layer 4, it also needs to fill the mating gap 10 between the sidewall of the rectangular slot 3 and the sidewall of the rectangular protective layer 4 adjacent to the facing surface. The screw head of the hexagon countersunk screw 8 is pressed against the surface of the corner pressure block 6, and passes through the reserved holes in the corner pressure block 6, the reserved areas of the edge areas of the rectangular protective layer 4, and the corresponding reserved holes of the rectangular conductive pad 5 in the z direction, and is then fastened to the electrode plate body at the bottom of the rectangular slot 3. A very small gap 9 is reserved between the top of the side wall rectangular groove guide rail 70 in the z direction and the bottom of the corner pressure block 6 in the z direction within the mating gap 10.

[0092] 2.2 Basic dimensions of the electrostatic deflection plate and rectangular slot The electrostatic deflection plate is made of oxygen-free copper, and its overall dimensions are: a length L of 300 mm along the beam propagation direction, and widths of 270 mm (x-direction) and 125 mm (y-direction) along the beam radial direction, as shown in the Cartesian coordinate system. Figure 2 .

[0093] A rectangular slot is formed on the beam-facing surface of the electrode plate body. The rectangular slot and the electrode plate body share a common z-axis of central symmetry, and both have a matched axisymmetric structure about this axis. The x-width of the rectangular slot opening is 229.5 mm, accounting for 85% of the x-width of the electrode plate, with a side width of 20.25 mm; the y-width is 102.94 mm, accounting for 82% of the y-width of the electrode plate, with a side width of 11.03 mm. The opening area accounts for 70% of the beam-facing surface area of ​​the electrode plate. The depth h of the rectangular slot along the beam transmission direction is 20 mm, accounting for 6.7% of the length of the electrode plate along the z-direction. This depth ensures that the protective layer has sufficient z-direction depth to sacrifice itself and withstand sputtering. The beam-facing surface of the rectangular slot is the pull-out opening.

[0094] 2.3 Composite protective layer like Figure 2 The rectangular slot contains a composite protective layer. Along the beam transmission direction, the composite protective layer consists of a removable rectangular protective layer and a rectangular conductive pad, from the outside to the inside.

[0095] The rectangular protective layer (hereinafter referred to as the protective layer) is made of high-purity graphite with a resistivity of 1.5 × 10⁻⁶. -5 Ω·cm. Boron ions are mainly sputtered by physical methods, while graphite has the advantages of low sputtering yield and minimal wafer contamination. Based on the design in section 2.2, the dimensions of the protective layer's beam-facing surface are: a width of 229.35 mm in the x-direction and a width of 102.79 mm in the y-direction; this design can cover the main bombardment area of ​​scattered ions on the electrostatic deflection plate in the beam envelope of the ion implanter in this embodiment. The thickness h1 of the protective layer along the z-direction is 19 mm.

[0096] A rectangular conductive pad (hereinafter referred to as the conductive pad) is placed between the protective layer and the bottom electrode plate of the rectangular slot, ensuring full and tight contact between the three to form a good and stable equipotential connection in the z-direction. The conductive pad is made of flexible graphite with a resistivity of 2.10. -4 The thickness h2 along the z-direction is 1 mm, Ω·cm. A clearance of d2=0.075 mm is left between the sidewall of the rectangular slot and the sidewall of the protective layer and conductive pad to compensate for thermal expansion and contraction and machining tolerances.

[0097] Flexible graphite conductive pads possess excellent conductivity, flexibility, elasticity, self-lubrication, and vacuum compatibility. Their coefficient of thermal expansion matches that of high-purity graphite, thus they also play the following important roles: First, they provide mechanical buffering and stress dispersion, filling microscopic unevenness and evenly dispersing clamping force to prevent damage to the high-purity graphite protective layer due to localized stress concentration. Second, through their excellent flexibility and elasticity, they adjust and compensate for the minor deformations caused by the thermal expansion and contraction of high-purity graphite and the oxygen-free copper electrode plate. Third, they protect the bottom surface of the slot, acting as a sacrificial friction layer to prevent scratches on the precision-machined surface of the electrode plate during pulling and pulling.

[0098] 2.4 Elastic Conductive Track To ensure both radial electrical contact of the composite protective layer and smooth pull-out in the z-direction, elastic conductive tracks are installed along the sidewalls of the slots within the mating gap between the rectangular slot sidewalls and the protective layer and conductive pad sidewalls. Two elastic conductive tracks are installed on each rectangular slot sidewall around the protective layer. Each elastic conductive track consists of a metal conductive track body, a metal spring, and a rectangular slot guide rail on the sidewall.

[0099] The sidewall rectangular groove guide rail is formed by milling a rectangular groove into the sidewall of a rectangular slot, with a radial depth d1 of 1.35 mm.

[0100] The metallic conductive track body extends along the z-direction, and the specific material is an aged elastic copper alloy, specifically a cobalt-beryllium copper alloy, model UNS C17500, with a resistivity of 3.5 × 10⁻⁶. -6 Ω·cm. This alloy possesses excellent elasticity, electrical conductivity, and fatigue resistance. The elastic copper alloy undergoes a self-lubricating treatment, such as surface silver plating. The elastic copper alloy conductive track body is CNC milled, with a radial thickness t1 of 1.095 mm.

[0101] The metal spring is positioned between the metal conductive track body and the rectangular groove guide rail on the side wall, extending along the z-direction. Its initial cross-section has a certain arc shape in the radial direction, with the apex of the arc facing the side wall of the protective layer. Figure 7 As shown. The specific material selected is an aged beryllium copper alloy with a high beryllium content, specifically model UNS C17000. This model of beryllium copper alloy possesses excellent elasticity, good electrical conductivity, fatigue resistance, cold soldering resistance, and vacuum compatibility; its resistivity is 7.5 × 10⁻⁶. -6 The beryllium copper alloy is treated with a self-lubricating process, such as surface silver plating, to achieve a thickness of 0.35 mm (Ω·cm). The beryllium copper alloy spring is formed by stamping. The elastic force of the beryllium copper spring points towards the sidewall of the protective layer, providing a continuous radial preload to the elastic copper alloy conductive track body. This keeps the elastic copper alloy conductive track body pressed firmly against the sidewall of the protective layer, forming a tight, sufficient, elastic, continuous, narrow surface contact. The beryllium copper spring also compensates for thermal expansion and contraction and machining tolerances.

[0102] During installation, the beryllium copper spring is first placed directly on the bottom surface of the rectangular slot guide rail on the side wall, allowing it to slide freely. Then, the elastic copper alloy conductive track body is inserted into the rectangular slot guide rail along the side wall of the slot, ensuring that the elastic copper alloy conductive track body is tightly fitted to the beryllium copper spring. All of the above processing and installation are completed within the narrow space of the rectangular slot, requiring precise fit between all parts and good engineering feasibility.

[0103] The depth of the rectangular groove guide rail along the normal direction of the rectangular slot sidewall is d1 = 1.35 mm. The fit clearance width between the rectangular slot sidewall and the protective layer and conductive pad sidewall is d2 = 0.075 mm. The thickness of the beryllium copper spring sheet after being flattened into a straight line is t2 = 0.35 mm. To ensure sufficient contact under any working condition, based on the design target t1 + t2 being slightly greater than d1 + d2, the thickness t1 of the elastic copper alloy conductive track body needs to be slightly greater than 1.075 mm, therefore 1.095 mm is chosen. Under this numerical relationship, most of the radial thickness of the elastic copper alloy conductive track body is located within the rectangular groove guide rail, thus the rectangular groove guide rail can provide good z-direction fixation. The beryllium copper spring sheet provides elastic support and radial preload at the radial bottom of the rectangular groove to compensate for the small radial displacement caused by thermal expansion and contraction. The elastic copper alloy conductive track body and the beryllium copper spring sheet work together to ensure long-term stable and reliable radial electrical contact.

[0104] Furthermore, the coefficient of thermal expansion of oxygen-free copper is approximately 16.8 × 10⁻⁶. -6 / K, cobalt-beryllium copper elastic copper alloy (UNS C17500) orbital body approximately 17.6·10 -6 / K, beryllium copper fragment (UNS C17000) approximately 17.0·10 -6 / K, the maximum difference in the coefficients of thermal expansion among the three is approximately 0.8 × 10 -6 / K. Based on the radial thickness of the metal conductive track body of 1.095 mm and the limit operating temperature rise of 80℃, the radial dimension change is estimated to be about 0.07 μm, which is much smaller than the 0.075 mm fitting clearance. Moreover, it is within the elastic compensation that the beryllium copper spring can provide, thus meeting the thermal expansion coefficient matching requirements.

[0105] 2.5 Corner clamps and fasteners like Figure 2 As shown, a clamping mechanism using corner clamping blocks and countersunk hexagonal screws is used to mechanically fix the protective layer, conductive pads, and electrode plate body within the rectangular slot.

[0106] The corner clamp (hereinafter referred to as the clamp) is made of the same material as the electrode plate body, namely oxygen-free copper. The angle formed by the clamp along the beam-facing surface and the side wall of the protective layer is 90°. The width of the clamp along the four edges of the beam-facing surface of the protective layer is 8 mm, and the depth h3 of the clamp inserted into the mating gap along the z-direction is 2.3 mm. One side of the clamp is pressed against each edge of the beam-facing surface of the protective layer, and the other side is inserted into the mating gap to fill it completely. The purpose of this is twofold: firstly, to prevent bombardment particles and sputtered particles from entering the mating gap, and secondly, to maintain a clean working environment for the internal elastic conductive track, avoiding particle deposition that could affect the long-term working stability of the internal elastic conductive track.

[0107] The corner clamping block is secured along each edge of the protective layer with five M2.5 socket head cap screws (nominal diameter 2.5 mm, head diameter approximately 5 mm) at even intervals, made of oxygen-free copper. The screw heads press against the surface of the corner clamping block and pass through pre-drilled holes in the clamping block, the edge areas of the protective layer, and the corresponding pre-drilled holes in the conductive pads along the z-direction before being fastened to the bottom electrode plate of the rectangular slot. After tightening, the screw heads are flush with the surface of the corner clamping block, without introducing additional geometric steps. When tightening the screws, the preload is transmitted through the corner clamping block to the edges of the protective layer's facing surface, pressing the protective layer and conductive pads tightly against the bottom surface of the slot, thus achieving mechanical fixation, electrical connection, and anti-disengagement in the z-direction. This ensures elastic contact between the elastic conductive track and the sidewalls of the protective layer and conductive pads, establishing a radial electrical connection.

[0108] Along the z-direction, the bottom of the sidewall rectangular groove guide rail adjoins the electrode plate body at the bottom of the rectangular slot. Considering thermal expansion and contraction compensation and machining tolerances, a 0.08 mm gap is reserved between the top of the sidewall rectangular groove guide rail along the z-direction and the bottom of the corner pressure block within the mating clearance. With machining tolerances as small as possible, the lengths along the z-direction of both the elastic copper alloy conductive track body and the beryllium copper spring sheet flattened into a straight line are equal to the length along the z-direction of the sidewall rectangular groove guide rail, which is L. t =20-2.3-0.08=17.62 mm, which is the design goal for achieving sufficient and stable continuous narrow surface contact in the radial direction. Due to the excellent elasticity of the beryllium copper spring sheet and the excellent elasticity of the elastic copper alloy conductive track body, it can effectively compensate for the small deviations caused by thermal expansion and contraction.

[0109] The rectangular groove guide rail on the side wall has a length of 17.62 mm along the z-direction and a radial groove depth of 1.35 mm. Taking the shortest, weakest edge in the y-direction after the electrode plate body is grooved, the remaining radial wall thickness is 11.03 - 1.35 = 9.68 mm, which is 7.2 times the radial groove depth. Therefore, the remaining radial wall thickness of the rectangular groove guide rail on the side wall is sufficient to meet the requirements for structural mechanical strength, stability, and reliability.

[0110] 2.6 Installation During assembly, such as Figure 6 and Figure 7As shown, firstly, the beryllium copper spring is placed directly on the bottom surface of the rectangular slot guide rail on the side wall, allowing it to slide freely. Then, the elastic copper alloy conductive track body is inserted into the rectangular slot guide rail along the z-direction, ensuring it adheres tightly to the beryllium copper spring. Next, the flexible graphite conductive pad and the high-purity graphite protective layer are placed sequentially into the rectangular slot along the z-direction. During this process, the sidewalls of the conductive pad and the protective layer slide along the elastic conductive track until the conductive pad reaches the bottom surface of the rectangular slot and contacts the electrode plate body, followed by the protective layer. When the protective layer is pushed into place, the initially arc-shaped beryllium copper spring is flattened into a straight line, allowing the beryllium copper spring and the elastic copper alloy conductive track body to naturally and fully engage with the rectangular slot guide rail. The sidewalls of the protective layer and the conductive pad, the elastic conductive track, and the sidewalls of the rectangular slot are in full and tight contact with each other. Finally, using corner blocks and countersunk hexagonal screws, the protective layer and the conductive pad are pressed and fixed to the bottom surface of the rectangular slot along the z-direction.

[0111] After the composite protective layer and elastic conductive track are assembled, the protective layer, conductive pads, and electrode plate bodies achieve good and stable mechanical fixation, anti-dislodgement, and pull-out performance through mechanical clamping force and the elastic conductive track. Simultaneously, the protective layer, conductive pads, and electrode plate bodies also achieve good and stable equipotential bonding in the z-direction; the sidewalls of the protective layer and conductive pads, and the sidewalls of the elastic conductive track and the rectangular slot of the electrode plate body also form fully continuous elastic elongated surface contacts, thus forming good and stable radial equipotential bonding. The height difference between the facing surface of the protective layer and the facing surface of the electrode plate body does not exceed 0.05 mm, thereby minimizing the impact on the distribution of the electrostatic deflection electric field.

[0112] 2.7 Replacement The high-purity graphite protective layer, flexible graphite conductive pad, and elastic conductive track are all independent, replaceable components. During replacement, simply loosen the hexagonal countersunk screws and remove the corner clamps to pull out the protective layer and conductive pad along the elastic conductive track. When the elastic conductive track is damaged or its elasticity diminishes, it needs to be replaced. The old track (including the beryllium copper spring and the elastic copper alloy conductive track body) can be pulled out of the rectangular groove guide rail on the side wall, and then the new track can be installed. The steps and standards for installing new elastic conductive tracks, conductive pads, and protective layers are the same as the aforementioned assembly steps.

[0113] 2.8 The specific design and technical implementation scheme of the other electrode of the electrostatic deflection plate in the X direction and the electrostatic deflection plate in the Y direction are similar to those described above, and will not be repeated here.

[0114] 2.9 In this embodiment, the reliable equipotential connection via a dual path between the high-purity graphite protective layer and the electrode plate body ensures that the entire beam-facing surface remains an intact equipotential surface even after the addition of the composite protective layer. Therefore, the replaceable protective structure achieves sputtering protection and convenient maintenance without affecting the basic electrostatic deflection scanning performance of the electrostatic deflection plate itself. B + After completing the electrostatic deflection scan, the wafer is finally implanted with ions at the Beamline terminal.

[0115] 3. Analysis of Beneficial Effects In B + Under low-energy, high-current injection conditions of 5 keV and 5 mA, this embodiment, based on the design concept of functional separation and synergy, sets a rectangular slot on the beam-facing surface of the electrostatic deflection plate. Based on this, the electrostatic deflection plate is divided into a flexibly replaceable composite protective layer and the original integral electrode plate body. The composite protective layer consists of a high-purity graphite protective layer and a flexible graphite conductive pad, with elastic conductive tracks to synergistically achieve the flexible replaceability of the composite protective layer. The flexible graphite conductive pad is responsible for achieving equipotential bonding, and also provides mechanical buffering, compensation for thermal expansion and contraction, and protection of the slot bottom surface. The high-purity graphite protective layer, as a sacrificial layer, is responsible for withstanding ion sputtering while achieving equipotential bonding with the electrode plate body through the dual paths of the flexible graphite conductive pad and the elastic conductive tracks, jointly providing the electrostatic deflection electric field with the electrode plate body. Furthermore, the elastic conductive track itself also embodies the design concept of functional separation and synergy: the elastic copper alloy conductive track body focuses on radial electrical connection, while the beryllium copper spring focuses on providing elastic preload. The two work together to achieve long-term stable and reliable radial contact and flexible replaceability of the composite protective layer.

[0116] Based on this, the beneficial effects of the replaceable protective structure in this embodiment can be described from two dimensions: first, the component-level performance effects brought about by each core component in the design technical solution; and second, the macroscopic performance effects achieved by the entire replaceable protective structure on the electrostatic deflection plate. Specifically, as follows: 3.1 Performance Effects at the Core Component Level 1) Elastic conductive track The elastic conductive track, as an integral component, has a stable and reliable working structure, good installation and disassembly. Its working principle and its role in the replaceable protective structure of the electrostatic deflection plate are as follows.

[0117] (1) Utilizing the excellent elasticity of the beryllium copper spring, the beryllium copper spring and the elastic copper alloy conductive track body can naturally and fully engage with the rectangular slot guide rail on the side wall. At the same time, the other radial side of the elastic copper alloy conductive track body will fully press the side wall of the high-purity graphite protective layer and the flexible graphite conductive pad, so that the side wall of the protective layer and the conductive pad, the elastic copper alloy conductive track body, the beryllium copper spring and the rectangular slot side wall electrode plate body form a tight and sufficient continuous narrow surface contact with each other, and can adapt to and compensate for the small displacement that may be caused by thermal expansion and contraction. Furthermore, the elastic conductive track adopts a multi-track parallel design, which is mutually redundant under normal conditions; when the radial electrical connection of one track may be poor due to various reasons, the remaining tracks can still independently ensure a good radial equipotential connection. Therefore, a good and reliable radial equipotential electrical connection can be formed between the side wall of the protective layer and the side wall electrode plate body of the rectangular slot.

[0118] (2) The elastic copper alloy conductive track body also serves as the pull-out track for the protective layer and conductive pads. Since both the beryllium copper spring and the elastic copper alloy conductive track body have good lubrication properties, the friction between the sub-components is low, the pull-out and sliding are smooth, and the elastic deformation of the beryllium copper spring is not hindered. Therefore, the elastic conductive track has good pull-out and wear resistance, which can ensure the good installability and replaceability of the composite protective layer.

[0119] 2) Splash resistance In the composite protective layer, the high-purity graphite protective layer acts as a sacrificial layer. Within its coverage area, it absorbs the majority of the bombardment from scattered ions and sputtering products, as well as the resulting contamination, replacing the original electrode plate surface. The electrode plate itself can maintain its original processing precision. Furthermore, corner clamps fill the mating gap between the protective layer sidewall and the slot sidewall adjacent to the beam-facing surface. This prevents bombardment and sputtering particles from entering the gap and maintains a clean working environment for the internal elastic conductive tracks, avoiding particle deposition that could affect the long-term stability of the internal elastic conductive tracks. Therefore, the composite protective layer exhibits excellent sputtering resistance. When the protective layer and corner clamps suffer morphological degradation or performance failure due to long-term sputtering, the sputtering resistance of the beam-facing surface can be restored by periodically replacing the protective layer, corner clamps, and conductive pads.

[0120] 3) Equipotential bonding The equipotential connection between the high-purity graphite protective layer and the electrode plate body consists of two paths: a flexible graphite conductive pad provides a large-area close contact in the beam transmission direction, serving as the main path; and a multi-track parallel design of elastic conductive tracks provides continuous narrow surface contact in the radial direction, becoming an auxiliary path with redundancy. The parallel connection of the main and auxiliary paths, their mutual cooperation and redundancy, ensure that the electrode plate body, conductive pad, elastic conductive tracks, and protective layer together constitute a complete equipotential body, guaranteeing the interference resistance and long-term reliability of the equipotential connection. The height difference between the beam-facing surface of the protective layer and the beam-facing surface of the electrode plate body does not exceed 0.05 mm, thus having minimal impact on the uniformity and long-term stability of the electrostatic deflection field. In summary, the electrostatic deflection plate with a replaceable protective structure in this embodiment exhibits basic electrostatic deflection scanning performance at the same level as traditional integral electrostatic deflection plates.

[0121] 4) Ease of replacing the composite protective layer The high-purity graphite protective layer, corner clamps, flexible graphite conductive pads, and elastic conductive tracks (including beryllium copper springs and the elastic copper alloy conductive track bodies) are all independently replaceable components. The high-purity graphite protective layer and corner clamps, being directly subjected to sputtering, need to be replaced promptly based on the sputtering damage or surface contamination status. The flexible graphite conductive pads and elastic conductive tracks, due to their protected working environment, can be replaced primarily based on their material condition, with more flexible replacement cycles. Replacing these components simply requires loosening the hexagonal countersunk screws and corner clamps, removing the old part, replacing it with the new one, and then re-tightening. The elastic conductive track can also be easily replaced via the rectangular groove guide rail on the side wall. Therefore, the replacement operation for each component is simple and quick. Each component can be replaced individually based on its actual wear condition or during routine equipment maintenance, offering flexible replacement options.

[0122] 3.2 Macroscopic performance effects achieved on the electrostatic deflection plate 1) It can effectively suppress the accumulation of electric field distortion. The beam-facing surface of a traditional monolithic electrostatic deflector plate serves as both the functional surface providing the basic deflection electric field and the sputtering bearing surface. When this surface is contaminated by sputtering or damaged during cleaning, the resulting microstructure deterioration directly leads to distortion of the electric field distribution between the electrode plates. This damage is irreversible and can only be tolerated or the entire plate must be replaced.

[0123] This design incorporates a replaceable composite protective layer (comprising a high-purity graphite protective layer and flexible graphite conductive pads) on the electrostatic deflector plate, integrated with the original electrode plate body. The high-purity graphite protective layer covers most of the beam-facing surface, sacrificing itself to withstand the majority of scattered ions and sputtering products. Within its coverage area, the electrode plate body is protected from sputtering and contamination, maintaining its original processing precision. While some areas are exposed at the four edges, these represent a small percentage of the surface and are located far from the high-flux region at the beam center. When the protective layer surface becomes contaminated or its morphology deteriorates due to prolonged sputtering, simply replacing the protective layer and conductive pads periodically restores most of the beam-facing surface to its initial precision. The flexible graphite conductive pads and elastic conductive tracks ensure good and reliable equipotential bonding in the z-direction and radial direction, respectively. The composite protective layer, consisting of the high-purity graphite protective layer and flexible graphite conductive pads, maintains controllable thermal load and long-term stable structural integrity and electrical connection reliability under low-energy, high-current beam conditions.

[0124] Based on the above, the composite protective layer structure of this embodiment can restore the surface state of the electrostatic deflection plate's beam-facing surface in a timely manner by periodically replacing the protective layer and conductive pads. This is beneficial for maintaining the uniformity of the deflection electric field at the initial level for a long time and can effectively avoid the continuous distortion and deterioration of the electric field caused by the accumulation of ion sputtering in traditional integral electrodes.

[0125] On the other hand, the height difference between the protective layer's facing surface and the electrode plate's facing surface does not exceed 0.05 mm, which is within the allowable range for maintaining the uniformity and long-term stability of the electrostatic deflection electric field. After the internal hexagon countersunk screws are tightened, the screw heads are flush with the surface of the corner clamping block, without introducing additional geometric steps. After assembly, the corner clamping block will slightly protrude from the electrode plate's surface and the protective layer, introducing local, static geometric discontinuities; however, based on the technical solution of this embodiment, this discontinuity only produces a very small and controllable local electric field distortion. Compared with the irreversible and continuously deteriorating dynamic electric field distortion caused by sputter contamination from ion bombardment, this embodiment replaces the much larger and continuously accumulating dynamic electric field distortion with a very small and controllable static electric field distortion, which is a reasonable engineering trade-off.

[0126] 2) Solving the problems of micro-discharge and breakdown Under boron ion implantation, the oxygen-free copper electrode surface of a traditional monolithic electrostatic deflector gradually forms a boron-copper mixed contamination layer and a sputtering damage layer through sputtering deposition. Under the influence of the deflection electric field, these contamination and damage layers induce localized electric field concentration, creating localized potential differences. This leads to frequent micro-discharges and arc erosion on the electrode surface. Arc erosion forms permanent pits on the electrode surface, and discharge damage further exacerbates the accumulation of the contamination layer. When the localized potential difference exceeds the breakdown threshold, the electrode surface breaks down. Micro-discharges and breakdown create a vicious cycle of "contamination damage - micro-discharge - more severe contamination damage - more frequent micro-discharges," which continuously affects the stability of the deflection electric field and gradually leads to irreversible damage to the electrode plate. This problem is more pronounced under conditions of high beam current, heavy ion implantation, strong deflection electric fields, and long-term operation.

[0127] This design isolates the contamination and damage layers within a high-purity graphite protective layer. The protective layer achieves a stable and reliable equipotential connection to the electrode plate body via conductive pads and elastic conductive tracks, ensuring the entire beam-facing surface is at the same potential. The high-purity graphite protective layer has a low sputtering yield, resulting in slow formation of the contamination and damage layers. Even if a boron-copper contamination layer is deposited on the protective layer surface, only a weak potential difference exists between the protective layer and the electrode plate body, possibly due to non-ideal equipotentiality. The resulting charge accumulation region is weak and unstable, insufficient to cause micro-discharge. Furthermore, the protective layer, being a consumable component, is replaced periodically, removing the contamination and damage layers before they can accumulate into a stable charge accumulation region. Based on these principles, the conditions for micro-discharge formation are eliminated at the source, thus preventing arc erosion damage to the electrode surface and micro-discharge breakdown of the electrode surface. In addition, the flexible graphite conductive pads themselves have good chemical stability and low outgassing rate, making them less prone to introducing new discharge risks due to their own degradation. Therefore, this solution can effectively solve the micro-discharge and breakdown problems of traditional monolithic electrostatic deflection plates during long-term operation under high-current boron ion implantation conditions.

[0128] 3) Solve maintenance difficulties Traditional integrated electrostatic deflection plates require complete disassembly and reassembly for maintenance, which is time-consuming. In this solution, when the protective layer and corner pressure block surfaces become contaminated or suffer sputtering damage to a predetermined level, or when the conductive pads and flexible conductive rails need replacement, only the hexagonal countersunk screws need to be loosened, the corner pressure blocks removed, the old parts pulled out, the new parts replaced, and reinstalled. No operation on the electrode plate itself is required, significantly reducing maintenance time. The flexible conductive rails and conductive pads ensure good and stable pull-out performance of the rectangular slot, as well as protection for the electrodes on the bottom and side walls of the slot, ensuring consistent slot accuracy even after multiple replacements. Therefore, the time for a single replacement operation is greatly reduced, significantly improving equipment utilization.

[0129] 4) Reduce costs While periodic offline chemical cleaning can temporarily alleviate electrode sputtering contamination in traditional monolithic electrostatic deflector plates, repeated chemical cleaning damages electrode surface precision, worsens surface roughness, and degrades electric field uniformity, leading to a gradual decrease in electrode performance. If cleaning is not timely and the electrodes are not completely failed, users often choose to continue operating with contamination due to the high replacement cost. This increases contamination in the vacuum chamber, ion beam, and even the wafer, further deteriorating ion implantation uniformity and reducing semiconductor chip performance and yield. Over time, the overall electrode plate material performance will continue to deteriorate until failure.

[0130] This solution significantly reduces sputtering and contamination on the electrode plate body under the effective protection of the composite protective layer, especially protecting the electrode plate body in the depth direction from sputtering. Therefore, only the composite protective layer and elastic conductive rails need to be replaced periodically according to actual use, and the replacement cost of these spare parts is far lower than that of a monolithic electrode plate. The electrode plate body can be reused for a long time and does not require frequent cleaning, which greatly extends its service life and ensures long-term stable operation. Therefore, compared with traditional monolithic electrostatic deflection plates, the electrostatic deflection plate with a replaceable protective structure of this invention significantly reduces the cost over its service life. Furthermore, contamination of the vacuum chamber, beam, and wafer is also reduced, which can effectively improve the performance and yield of semiconductor chips.

[0131] 5) The protective layer in the composite protective layer uses high-purity graphite with excellent sputtering resistance. Graphite has low sputtering yield and causes less wafer contamination. Therefore, the replaceable protective structure can effectively reduce sputtering contamination (especially metal particles) of the charged particle beam on the electrostatic deflector plate, thereby effectively mitigating the impact of sputtering contamination on the vacuum chamber walls, downstream beam elements, and wafer surface. This also improves beam performance and semiconductor chip yield. This beneficial effect is more prominent in the low-energy, high-current boron ion implantation conditions of 5 keV and 5 mA in this embodiment.

[0132] 4. Summary This solution is based on the design concept of functional separation and synergy. The electrostatic deflection plate is divided into a flexibly replaceable composite protective layer and the original integral electrode plate body. The composite protective layer consists of a high-purity graphite protective layer and a flexible graphite conductive pad, with an elastic conductive track to synergistically achieve the flexible replaceability of the composite protective layer. The elastic conductive track itself also embodies the design concept of functional separation and synergy: the elastic copper alloy conductive track body focuses on radial electrical connection, while the beryllium copper spring focuses on providing elastic preload. Together, they achieve long-term stable and reliable radial contact and the flexible replaceability of the composite protective layer.

[0133] By using a high-purity graphite protective layer as a sacrificial layer for sputtering and ensuring equipotential bonding between the protective layer and the electrode plate body, this solution effectively addresses the problems of electric field distortion, micro-discharge and breakdown, maintenance difficulties, and high costs caused by ion sputtering contamination in traditional monolithic electrostatic deflection plates. It effectively ensures the long-term stability and service life of the electrostatic deflection plate itself, and also provides a guarantee for achieving higher doping precision and yield in semiconductor devices. This solution is simple, easy to manufacture, and suitable for industrial application.

[0134] Example 2: Replaceable protective structure for electrostatic deflection plates used in low-energy high-current arsenic ion implantation 1. Application Background and Ion Beam Parameters This embodiment describes low-energy, high-current arsenic ion implantation for the fabrication of the emitter of an NPN bipolar transistor in an advanced bipolar-CMOS silicon integrated circuit chip. The implanted ion is arsenic, the implantation energy is 25 keV, and the implantation dose is 1.10. 16 cm -2 The beam current intensity is 12 mA.

[0135] First, arsenic ions (as monovalent arsenic ions As) are generated using an ion source. + (For example) After that, As is transferred through the acceleration-deceleration electrodes. + The ion kinetic energy is controlled to 25 keV. Then, a magnetic field analyzer is used to analyze and screen the charge-to-mass ratio. During the entire beam transmission process, a necessary quadrupole lens is used to focus the beam laterally. Finally, a pair of electrostatic deflection plates are used to scan and deflect the beam in the X and Y directions. Finally, ion implantation is performed on the silicon wafer.

[0136] As before reaching the electrostatic deflection plate + The kinetic energy is 25 keV, and the beam current is 12 mA. This operating condition exhibits a strong space charge effect, resulting in significant lateral beam divergence. Ions at the edge of the beam envelope continuously bombard the beam-facing surface of the electrostatic deflection plate. Arsenic ions have a high mass number (75 amu), resulting in a significantly higher physical sputtering yield than lighter ions such as phosphorus and boron. The strong beam current leads to an extremely high absolute flux of scattered ions, making the cumulative physical sputtering effect even more pronounced. The deposition of scattered ions and self-sputtering products on the electrode plate surface forms an arsenic-metal mixed contamination layer, causing electric field distortion, micro-discharge, and breakdown, affecting ion scanning uniformity and emitter doping accuracy.

[0137] 2. Geometric design and technical implementation of replaceable protective structure for electrostatic deflection plates. To address the aforementioned operating conditions, the replaceable protective structure described in this invention is employed in the electrostatic deflection plates of the ion implanter to solve the above problems. A pair of electrostatic deflection plates are used to scan and deflect the beam in the X and Y directions respectively. The replaceable protective structure is used for both the X and Y direction electrostatic deflection plates, and is applied to both the positive and negative electrodes of the electrostatic deflection plates. Here, only the specific technical solution for the positive electrode of the X-direction electrostatic deflection plate is given; the others are similar.

[0138] 2.1 Overview of the Replaceable Protective Structure Design for Electrostatic Deflection Plates like Figure 3 , Figure 4-7 As shown, the replaceable protective structure of the electrostatic deflection plate in the X direction of the ion implanter includes a positive electrode plate body 1, a negative electrode plate body 2, a trapezoidal slot 3 located on the beam-facing surface of the electrode plate body, and a composite protective layer disposed within the trapezoidal slot 3. Along the beam transmission direction, the composite protective layer structure includes, from the outside to the inside, a retractable trapezoidal protective layer 4 and a trapezoidal conductive pad 5.

[0139] A fitting gap 10 is provided between the sidewall of the trapezoidal slot 3 and the sidewalls of the trapezoidal protective layer 4 and the trapezoidal conductive pad 5. The elastic conductive track 7, which is provided on the sidewall of the trapezoidal slot 3, is also located within the fitting gap 10. The elastic conductive track 7 spans the fitting gap 10 and contacts the sidewalls of the trapezoidal protective layer 4 and the trapezoidal conductive pad 5. The elastic conductive track 7 includes a rectangular groove guide rail 70 on the sidewall, a metal spring 700, and a metal conductive track body 007.

[0140] The corner pressure block 6 is arranged around the perimeter of the facing opening of the trapezoidal slot 3. While pressing against the edges of the facing surface of the trapezoidal protective layer 4, it also fills the mating gap 10 between the sidewall of the trapezoidal slot 3 and the sidewall of the trapezoidal protective layer 4 adjacent to the facing surface. The screw head of the internal hex countersunk screw 8 is pressed against the surface of the corner pressure block 6, and after passing through the reserved holes in the reserved areas of the corner pressure block 6 and the edge area of ​​the trapezoidal protective layer 4 in the z direction, it is fastened to the side wall electrode plate body of the trapezoidal slot 3. During this process, the screw does not pass through the trapezoidal conductive pad 5. The side wall rectangular groove guide rail 70 has a very small gap 9 reserved between the top of the trapezoidal slot 3 side wall and the bottom of the corner pressure block 6 in the mating gap 10.

[0141] 2.2 Dimensions of the electrostatic deflection plate base and trapezoidal slot The electrostatic deflection plate is made of oxygen-free copper, and its overall dimensions are: a length L of 320 mm along the beam propagation direction, and widths of 290 mm (x-direction) and 135 mm (y-direction) along the beam radial direction, as shown in the Cartesian coordinate system. Figure 3 .

[0142] A trapezoidal slot is formed on the beam-facing surface of the electrode plate body. The opening width of the trapezoidal slot gradually narrows along the z-direction, and its cross-section in the xoy plane is always rectangular. The trapezoidal slot and the electrode plate body share a common z-direction central axis of symmetry, and both have a matched axisymmetric structure about this central axis. The design dimensions of the trapezoidal slot are as follows: the wide end rectangle near the beam-facing surface has a width of 250.85 mm in the x-direction, accounting for 86.5% of the electrode plate's x-direction width, with a side width of 19.58 mm; the width in the y-direction is 115.33 mm, accounting for 85.4% of the electrode plate's y-direction width, with a side width of 9.84 mm. The opening area of ​​the beam-facing surface accounts for 73.9% of the area of ​​the beam-facing surface of the electrode plate. The narrow end rectangle at the bottom of the trapezoidal slot has a width of 200.68 mm in the x-direction and a width of 92.26 mm in the y-direction. The trapezoidal slot has a depth h of 22 mm along the beam propagation direction, which is 6.9% of the electrode plate's length L along the z-direction. This depth ensures that the protective layer has sufficient z-direction depth to sacrifice itself and withstand sputtering. The beam-facing surface of the trapezoidal slot is the pull-out opening.

[0143] 2.3 Composite protective layer like Figure 3 The trapezoidal slot contains a composite protective layer. Along the beam transmission direction, the composite protective layer consists of a removable trapezoidal protective layer and a trapezoidal conductive pad, from the outside to the inside.

[0144] Arsenic ion implantation is primarily performed via physical sputtering. Arsenic is a heavy ion, resulting in high sputtering yield. Therefore, the trapezoidal protective layer (referred to as the protective layer) is made of molybdenum (Mo), which has a high sputtering threshold and stronger sputtering resistance; its resistivity is 5.3 × 10⁻⁶. -6 Ω·cm. Based on design 2.2, the trapezoidal protective layer has the following dimensions: a rectangular opening near the beam-facing surface with a width of 250.7 mm in the x-direction and 115.18 mm in the y-direction. A rectangular opening at the bottom of the trapezoidal slot with a width of 200.53 mm in the x-direction and 92.11 mm in the y-direction. This design can cover the main bombardment area of ​​scattered ions on the electrostatic deflection plate in the beam envelope of the ion implanter in this embodiment. The thickness h1 of the protective layer along the z-direction is 21 mm.

[0145] A trapezoidal conductive pad (hereinafter referred to as the conductive pad) is placed between the protective layer and the bottom electrode plate of the trapezoidal slot, ensuring full and tight contact among the three to form a good and stable equipotential connection in the z-direction. The conductive pad is made of flexible graphite with a resistivity of 2.10. -4 The thickness h2 along the z-direction is 1 mm, Ω·cm. Along the normal direction of the trapezoidal slot sidewall, there is a mating clearance of d2=0.075 mm between the trapezoidal slot sidewall and the protective layer and conductive pad sidewall to compensate for thermal expansion and contraction and machining tolerances.

[0146] Flexible graphite conductive pads possess excellent conductivity, flexibility, elasticity, self-lubrication, and vacuum compatibility. Therefore, they also play the following important roles: First, they provide mechanical buffering and stress dispersion, filling microscopic unevenness, uniformly dispersing clamping force, and preventing damage to the molybdenum protective layer due to localized stress concentration. Second, through the excellent flexibility and elasticity of flexible graphite, they adjust and compensate for the minor deformation caused by thermal expansion and contraction between the molybdenum protective layer and the oxygen-free copper electrode plate body. Third, they protect the bottom surface of the slot, acting as a sacrificial friction layer to prevent scratches on the precision-machined electrode plate body surface during pulling.

[0147] 2.4 Elastic Conductive Track To ensure both radial electrical contact and smooth pull-out of the composite protective layer, elastic conductive tracks are installed along the sidewalls of the trapezoidal slots within the mating gap between the sidewalls of the trapezoidal slots and the protective layer and conductive pad sidewalls. Two elastic conductive tracks are provided on each trapezoidal slot sidewall around the protective layer. Each elastic conductive track consists of a metal conductive track body, a metal spring, and a rectangular groove guide rail on the sidewall.

[0148] The rectangular groove guide rail is formed by milling a rectangular groove into the side wall of the trapezoidal slot, with a radial depth (along the normal direction of the side wall of the trapezoidal slot) d1=1.5 mm.

[0149] The metal conductive track body extends along the rectangular groove guide rail on the side wall. The specific material is an aged elastic copper alloy, specifically a cobalt-beryllium copper alloy, model UNS C17500, with a resistivity of 3.5 × 10⁻⁶. -6 Ω·cm. This alloy possesses excellent elasticity, electrical conductivity, and fatigue resistance. The elastic copper alloy undergoes a self-lubricating treatment, such as surface silver plating. The elastic copper alloy track body is CNC milled, with a radial thickness t1 of 1.215 mm.

[0150] A metal spring is positioned between the metal conductive track body and the rectangular groove guide rail on the side wall, extending along the rectangular groove guide rail. Its initial cross-section is an arc with a certain curvature in the radial direction, with the apex of the arc facing the side wall of the protective layer. Figure 7 As shown. To better cope with stronger beam weight (As + For the higher heat load conditions of ion implantation, a beryllium copper alloy with a higher elastic limit and undergoing aging treatment is selected. This alloy has a high beryllium content and uses model UNS C17200. This model of beryllium copper alloy has a higher elastic limit and better stress relaxation resistance than C17000 in Example 1, and also has good electrical conductivity, fatigue resistance, cold welding resistance, and vacuum compatibility; its resistivity is 7.8 × 10⁻⁶. -6 Ω·cm. The beryllium copper alloy is treated with a self-lubricating process, such as surface silver plating. The beryllium copper alloy spring is formed by stamping. As +The increased thermal load from ion implantation and the greater difference in thermal expansion coefficients between molybdenum and copper necessitate a slight increase in the thickness of the beryllium copper spring, t2 = 0.38 mm. This enhances its resilience and ensures long-term reliable radial contact. The elastic force of the beryllium copper spring points towards the sidewall of the protective layer, providing a continuous radial preload to the elastic copper alloy conductive track body. This keeps the elastic copper alloy conductive track body pressed firmly against the sidewall of the protective layer, forming a tight, sufficient, continuous, narrow surface contact. The beryllium copper spring also compensates for thermal expansion and contraction and machining tolerances.

[0151] During installation, the beryllium copper spring is first placed directly on the bottom surface of the rectangular groove guide rail on the side wall, allowing it to slide freely. Then, the elastic copper alloy conductive track body is inserted into the rectangular groove guide rail along the side wall of the slot, ensuring that the elastic copper alloy conductive track body is tightly fitted to the beryllium copper spring. All of the above processing and installation are completed within the narrow space of the trapezoidal slot, requiring guaranteed precision in the fit between all parts and good engineering feasibility.

[0152] The radial depth of the rectangular groove guide rail is d1 = 1.5 mm, the fit clearance width between the trapezoidal slot sidewall and the protective layer and conductive pad sidewall is d2 = 0.075 mm, and the thickness of the beryllium copper spring sheet after being flattened into a straight line is t2 = 0.38 mm. To ensure sufficient contact under any working condition, based on the design target t1 + t2 being slightly greater than d1 + d2, the thickness t1 of the elastic copper alloy conductive track body needs to be slightly greater than 1.195 mm, therefore 1.215 mm is chosen. Under this numerical relationship, most of the radial thickness of the elastic copper alloy conductive track body is located within the rectangular groove guide rail, thus the rectangular groove guide rail can provide good fixation along the trapezoidal slot sidewall direction; the beryllium copper spring sheet provides elastic support and radial preload at the radial bottom of the rectangular groove guide rail to compensate for the small radial displacement caused by thermal expansion and contraction. The elastic copper alloy conductive track body and the beryllium copper spring sheet work together to ensure long-term stable and reliable radial electrical contact.

[0153] Furthermore, the coefficient of thermal expansion of oxygen-free copper is approximately 16.8 × 10⁻⁶. -6 / K, cobalt-beryllium copper elastic copper alloy (UNS C17500) orbital body approximately 17.6·10 -6 / K, beryllium copper fragment (UNS C17200) approximately 17.8·10 -6 / K, the maximum difference in the coefficients of thermal expansion among the three is approximately 1.0·10 -6 / K. Based on the radial thickness of the metal conductive track body of 1.215 mm and the extreme operating temperature rise of 80℃, the radial dimension change is estimated to be about 0.10 μm, which is much smaller than the 0.075 mm fitting gap, and is within the elastic compensation that the beryllium copper spring can provide. Therefore, it meets the thermal expansion coefficient matching requirements.

[0154] 2.5 Corner clamps and fasteners like Figure 3 As shown, corner clamps and countersunk hexagonal screws are used to mechanically fix the protective layer, conductive pads and electrode plate body inside the trapezoidal slot.

[0155] The corner clamp (hereinafter referred to as the clamp) is made of the same material as the electrode plate body, namely oxygen-free copper. The angle formed by the clamp along the beam-facing surface and the side wall of the protective layer is consistent with the inclination angle of the trapezoidal slot side wall, namely 48.8° in the x direction and 27.7° in the y direction. The width of the clamp along the four edges of the beam-facing surface of the protective layer is 8 mm, and the insertion depth h3 of the clamp along the side wall of the slot is 2.3 mm. One side of the clamp is pressed against each edge of the beam-facing surface of the protective layer, and the other side is inserted into the fitting gap to fill it completely. The purpose of this is to prevent bombardment particles and sputtered particles from entering the fitting gap, and to keep the working environment of the internal elastic conductive track clean, so as to avoid particle deposition affecting the long-term working stability of the internal elastic conductive track.

[0156] The corner clamping block is secured at even intervals along each edge of the protective layer's facing surface using five M2.5 socket head cap screws (nominal diameter 2.5 mm, head diameter approximately 5 mm) made of oxygen-free copper. The screw heads press against the corner clamping block surface, pass through pre-drilled holes along the z-direction in the clamping block and protective layer's edge areas, cross the mating gap, and are fastened to the electrode plate body on the slot sidewall. During this process, the screws do not pass through the conductive washers. The socket head cap screws should be positioned on the trapezoidal slot sidewall body outside the area covered by the elastic conductive track, ensuring that the screws do not contact the elastic conductive track or are too close to it. After tightening, the screw heads are flush with the corner clamping block surface, without introducing any additional geometric steps. When the screw is tightened and pressed, its preload is transmitted to the edges of the protective layer's facing surface through the corner pressure block, pressing the protective layer and conductive pad tightly against the bottom surface of the trapezoidal slot, thereby achieving mechanical fixation, electrical connection, and anti-dislodgement in the z-direction; thus, the elastic conductive track maintains elastic contact with the sidewalls of the protective layer and conductive pad, and the radial electrical connection is also established.

[0157] Along the sidewall of the trapezoidal slot, the bottom of the rectangular groove guide rail of the sidewall is adjacent to the bottom electrode plate body of the trapezoidal slot. Considering compensation for thermal expansion and contraction and machining tolerances, a 0.08 mm gap is reserved between the top of the rectangular groove guide rail of the sidewall and the bottom of the corner pressure block within the fitting clearance. With machining tolerances as small as possible, the lengths of the elastic copper alloy conductive track body and the beryllium copper spring sheet flattened into a straight line along the sidewall of the trapezoidal slot are both equal to the length L of the rectangular groove guide rail of the sidewall of the trapezoidal slot along the sidewall. t That is, along the x-direction sidewall, L tx =22 / cos48.8°-2.3-0.08=30.95 mm; along the y-direction sidewall, L ty=22 / cos27.7°-2.3-0.08=22.48 mm; This is the design goal for achieving sufficient and stable continuous narrow surface contact in the radial direction. The beryllium copper spring has excellent elasticity, and the elastic copper alloy conductive track body also has excellent elasticity, thus effectively compensating for minor deviations caused by thermal expansion and contraction.

[0158] Regarding the mechanical strength stability of the sidewall rectangular slot guide rail, taking the weakest point in the y-direction (wide end) as an example, at the section below the insertion end of the corner pressure block (2.38 mm from the facing surface along the trapezoidal slot sidewall), the radial slot depth of the sidewall rectangular slot guide rail along the trapezoidal slot sidewall, projected onto the y-axis, is 1.5 × cos27.7° = 1.33 mm. Here, the remaining wall thickness along the y-direction after slotting the sidewall rectangular slot guide rail is 9.84 - 1.33 = 8.51 mm, which is 6.4 times the y-axis projected slot depth. Therefore, the remaining wall thickness of the sidewall rectangular slot guide rail is sufficient to meet the requirements for structural mechanical strength stability and reliability.

[0159] 2.6 Installation During assembly, such as Figure 6 and Figure 7 As shown, firstly, the beryllium copper spring is placed directly on the bottom surface of the rectangular groove guide rail on the side wall, allowing it to slide freely. Then, the elastic copper alloy conductive track body is inserted into the rectangular groove guide rail on the side wall, ensuring it is tightly against the beryllium copper spring. Next, the flexible graphite conductive pad and the molybdenum protective layer are placed sequentially into the slot. During this process, the side walls of the conductive pad and the protective layer slide along the elastic conductive track until the conductive pad reaches the bottom surface of the trapezoidal slot and contacts the electrode plate body, followed by the protective layer. When the protective layer is pushed into place, the initially arc-shaped beryllium copper spring is flattened into a straight line, allowing the beryllium copper spring and the elastic copper alloy conductive track body to naturally and fully engage with the rectangular groove guide rail on the side wall. The side walls of the protective layer and the conductive pad, the elastic conductive track, and the trapezoidal slot side walls are in close and sufficient contact with each other. Finally, using a corner clamp and countersunk hexagonal screws, the protective layer and the conductive pad are mechanically pressed and fixed along the z-direction.

[0160] After the composite protective layer and elastic conductive track are assembled, the protective layer, conductive pads, and electrode plate bodies achieve good and stable mechanical fixation, anti-dislodgement, and pull-out performance through mechanical clamping force and the elastic conductive track. Simultaneously, the protective layer, conductive pads, and electrode plate bodies also achieve good and stable equipotential bonding in the z-direction; the sidewalls of the protective layer and conductive pads, the elastic conductive track and the trapezoidal slot sidewalls of the electrode plate body also form sufficiently continuous elastic narrow surface contacts, thus forming good and stable radial equipotential bonding. The height difference between the facing surface of the molybdenum protective layer and the facing surface of the electrode plate body does not exceed 0.05 mm, thereby minimizing the impact on the distribution of the electrostatic deflection electric field.

[0161] 2.7 Replacement The molybdenum protective layer, flexible graphite conductive pad, and elastic conductive track are all independent, replaceable components. During replacement, simply loosen the hexagonal countersunk screws and remove the corner clamps to pull the protective layer and conductive pad along the elastic conductive track. When the elastic conductive track is damaged or its elasticity has diminished, it needs to be replaced. The old track (including the beryllium copper spring and the elastic copper alloy conductive track body) can be pulled out along the rectangular groove guide rail on the side wall, and then the new track can be installed. The steps and standards for installing new elastic conductive tracks, conductive pads, and protective layers are the same as the aforementioned assembly steps.

[0162] It should be noted that, since the countersunk hexagonal screws are installed last and removed first, this assembly and disassembly sequence ensures that the trapezoidal slot does not interfere with the track during operation.

[0163] 2.8 The specific design and technical implementation scheme of the other electrode of the electrostatic deflection plate in the X direction and the electrostatic deflection plate in the Y direction are similar to those described above, and will not be repeated here.

[0164] 2.9. In this embodiment, the reliable equipotential connection between the molybdenum protective layer and the oxygen-free copper electrode plate body via a dual-path system ensures that the entire beam-facing surface remains an intact equipotential surface even after the addition of the composite protective layer. Therefore, the replaceable protective structure achieves sputtering protection and convenient maintenance without affecting the basic electrostatic deflection scanning performance of the electrostatic deflection plate itself. As + After completing the electrostatic deflection scan, the wafer is finally implanted with ions at the Beamline terminal.

[0165] 3. Analysis of Beneficial Effects In As +Under low-energy, high-current heavy ion implantation conditions of 25 keV and 12 mA, this embodiment, based on the design concept of functional separation and synergy, sets a trapezoidal slot on the beam-facing surface of the electrostatic deflection plate. Based on this, the electrostatic deflection plate is divided into a flexibly replaceable composite protective layer and the original integral electrode plate body. The composite protective layer consists of a molybdenum protective layer and flexible graphite conductive pads, with elastic conductive tracks to synergistically achieve the flexible replaceability of the composite protective layer. The flexible graphite conductive pads are responsible for providing the equipotential bonding foundation, as well as providing multiple functions such as mechanical buffering, compensating for thermal expansion and contraction, and protecting the bottom surface of the slot. The molybdenum protective layer, as a sacrificial layer, is responsible for withstanding ion sputtering while achieving equipotential bonding with the electrode plate body through the dual paths of the flexible graphite conductive pads and elastic conductive tracks, jointly providing the electrostatic deflection electric field with the electrode plate body. Furthermore, the elastic conductive track itself also embodies the design concept of functional separation and synergy: the elastic copper alloy conductive track body focuses on radial electrical connection, while the beryllium copper spring focuses on providing elastic preload. The two work together to achieve long-term stable and reliable radial electrical contact and flexible replaceability of the composite protective layer.

[0166] Based on this, the beneficial effects of the replaceable protective structure in this embodiment can be described from two dimensions: first, the component-level performance effects brought about by each core component in the design technical solution; and second, the macroscopic performance effects achieved by the entire replaceable protective structure on the electrostatic deflection plate. Specifically, as follows: 3.1 Performance Effects at the Core Component Level 1) Elastic conductive track The elastic conductive track, as an integral component, has a stable and reliable working structure, good installation and disassembly capabilities, and its working principle and role in the replaceable protective structure of the electrostatic deflection plate are as follows.

[0167] (1) Utilizing the excellent elasticity of the beryllium copper spring, the beryllium copper spring and the elastic copper alloy conductive track body can naturally and fully engage with the rectangular slot guide rail on the side wall. At the same time, the other radial side of the elastic copper alloy conductive track body will fully press the side wall of the molybdenum protective layer and the flexible graphite conductive pad, so that the side wall of the protective layer and the conductive pad, the elastic copper alloy conductive track body, the beryllium copper spring and the trapezoidal slot side wall electrode plate body form a tight and sufficient continuous narrow surface contact with each other, and can adapt to and compensate for the small displacement that may be caused by thermal expansion and contraction. Furthermore, the elastic conductive track adopts a multi-track parallel design, which is mutually redundant under normal conditions; when the radial electrical connection of one track may be poor due to various reasons, the remaining tracks can still independently ensure a good radial equipotential connection. Therefore, a good and reliable radial equipotential electrical connection can be formed between the side wall of the protective layer and the side wall electrode plate body of the trapezoidal slot.

[0168] (2) The elastic copper alloy conductive track body also serves as the pull-out track for the molybdenum protective layer and the flexible graphite conductive pad. Since both the beryllium copper spring and the elastic copper alloy conductive track body have good lubrication properties, the friction between the sub-components is low, the pull-out and sliding are smooth, and the elastic deformation of the beryllium copper spring is not hindered. Therefore, the elastic conductive track has good pull-out and wear resistance, which can ensure the good installability and replaceability of the composite protective layer.

[0169] 2) Splash resistance In the composite protective layer, the molybdenum protective layer acts as a sacrificial layer. Within its coverage area, it absorbs the majority of the bombardment from scattered ions and sputtering products, as well as the resulting contamination, replacing the original electrode plate surface. This allows the electrode plate to maintain its original processing precision. Furthermore, by using corner clamps to fill the gap between the molybdenum protective layer sidewall and the trapezoidal slot sidewall near the beam-facing surface, bombardment and sputtering particles are prevented from entering the gap. This also maintains a clean working environment for the internal elastic conductive tracks, preventing particle deposition from affecting their long-term operational stability. Moreover, the high sputtering threshold of the molybdenum protective layer makes ion sputtering more difficult. Therefore, the composite protective layer structure exhibits stronger sputtering resistance than Example 1, better coping with high beam current (As). + Ion implantation conditions. The service life of the molybdenum protective layer is also longer. When the molybdenum protective layer and corner blocks suffer morphological degradation or performance failure due to long-term sputtering, the sputtering resistance of the beam-facing surface can be restored by periodically replacing the protective layer, corner blocks, and conductive pads.

[0170] The trapezoidal slot in this embodiment also has the advantage that, because its cross-section gradually narrows along the z-direction, it mitigates the weakening of structural strength caused by increasing the opening area to increase the protective layer coverage area. This allows the trapezoidal slot to have a larger opening area on the beam-facing side, resulting in a more comprehensive protective layer coverage area. Therefore, its upper limit for area ratio is higher than that of the rectangular slot scheme under the same conditions, making it more suitable for the high-current beam weight (As) requirements of this embodiment. + Ion implantation conditions.

[0171] 3) Equipotential bonding The equipotential connection between the molybdenum protective layer and the electrode plate body consists of two paths: a flexible graphite conductive pad provides a large-area, tight contact in the beam transmission direction, serving as the main path; and a multi-track parallel design of elastic conductive tracks provides tight, sufficient, continuous, narrow-surface contact in the radial direction, becoming an auxiliary path with redundancy. The parallel connection of the main and auxiliary paths, their mutual cooperation and redundancy, ensure that the electrode plate body, conductive pad, elastic conductive tracks, and protective layer together constitute a complete equipotential body, guaranteeing the interference resistance and long-term reliability of the equipotential connection. The height difference between the beam-facing surface of the protective layer and the beam-facing surface of the electrode plate body does not exceed 0.05 mm, thus having minimal impact on the uniformity and long-term stability of the electrostatic deflection field. In summary, the electrostatic deflection plate with a replaceable protective structure in this embodiment exhibits basic electrostatic deflection scanning performance at the same level as traditional integral electrostatic deflection plates.

[0172] 4) Ease of replacing the composite protective layer The molybdenum protective layer, corner clamps, flexible graphite conductive pads, and elastic conductive tracks (including beryllium copper springs and the elastic copper alloy conductive track body) are all independently replaceable components. Among them, the molybdenum protective layer and corner clamps, because they are directly subjected to sputtering, need to be replaced promptly based on the sputtering damage or surface contamination status; compared to Example 1, the molybdenum protective layer has a longer service life and a longer replacement cycle. The flexible graphite conductive pads and elastic conductive tracks, due to their protected working environment, can be replaced primarily based on their material condition, allowing for more flexible and extended replacement cycles. When replacing these components, simply loosen the hexagonal countersunk screws and corner clamps, remove the old part, replace it with the new part, and retighten. The elastic conductive track can also be easily replaced via the rectangular groove guide rail on the side wall. Therefore, the replacement operation for each component is simple and quick. Each component can be replaced individually based on its actual wear condition or during routine equipment maintenance, offering flexible replacement methods.

[0173] 3.2 Macroscopic performance effects achieved on the electrostatic deflection plate 1) It can effectively suppress the accumulation of electric field distortion. The beam-facing surface of a traditional monolithic electrostatic deflector plate serves as both the functional surface providing the basic deflection electric field and the sputtering bearing surface. When this surface is contaminated by sputtering or damaged during cleaning, the resulting microstructure deterioration directly leads to distortion of the electric field distribution between the electrode plates. This damage is irreversible and can only be tolerated or the entire plate must be replaced.

[0174] This design incorporates a replaceable composite protective layer (including a molybdenum protective layer and flexible graphite conductive pads) on the electrostatic deflector plate, along with the original electrode plate body. The molybdenum protective layer covers most of the beam-facing surface, sacrificing itself to withstand the majority of scattered ions and self-sputtering products. Within its coverage area, the electrode plate body is protected from sputtering and contamination, maintaining its original machining accuracy. While there is some exposed area at the four edges, this area is small and located far from the high-flux region of the beam center. When the surface of the molybdenum protective layer becomes contaminated or degraded due to prolonged sputtering, simply replacing the molybdenum protective layer and the flexible graphite conductive pads periodically restores the surface condition of most of the beam-facing surface to its initial accuracy. The flexible graphite conductive pads and elastic conductive tracks ensure good and reliable equipotential bonding in the z-direction and radial direction, respectively. The composite layer consisting of the molybdenum protective layer and the flexible graphite conductive pads maintains controllable thermal load and long-term stable structural integrity and electrical connection reliability under low-energy, high-current heavy ion implantation conditions.

[0175] Based on the above, the composite protective layer structure of this embodiment can restore the surface condition of the electrode plate body's beam-facing surface in a timely manner by periodically replacing the molybdenum protective layer and the flexible graphite conductive pad. This is beneficial for maintaining the uniformity of the deflection electric field at the initial level for a long time and can effectively avoid the continuous distortion and deterioration of the electric field caused by the accumulation of ion sputtering in traditional integral electrodes.

[0176] On the other hand, the height difference between the molybdenum protective layer's facing surface and the electrode plate's facing surface does not exceed 0.05 mm, which is within the allowable range for maintaining the uniformity and long-term stability of the electrostatic deflection electric field. After the internal hexagon countersunk screws are tightened, the screw heads are flush with the surface of the corner clamping block, without introducing additional geometric steps. After assembly, the corner clamping block will slightly protrude from the electrode plate's surface and the protective layer, introducing local, static geometric discontinuities; however, based on the technical solution of this embodiment, this discontinuity only produces a very small and controllable local electric field distortion. Compared with the irreversible and continuously deteriorating dynamic electric field distortion caused by sputter contamination from ion bombardment, this embodiment replaces the much larger and continuously accumulating dynamic electric field distortion with a very small and controllable static electric field distortion, which is a reasonable engineering trade-off.

[0177] 2) Solving the problems of micro-discharge and breakdown Under arsenic ion implantation conditions, the oxygen-free copper electrode surface of a traditional monolithic electrostatic deflector gradually forms an arsenic-copper mixed contamination layer and a sputtering damage layer through sputtering deposition. Under the influence of the deflection electric field, these contamination and damage layers induce localized electric field concentration, creating localized potential differences. This leads to frequent micro-discharges and arc erosion on the electrode surface. Arc erosion forms permanent pits on the electrode surface, and discharge damage further exacerbates the accumulation of the contamination layer. When the localized potential difference exceeds the breakdown threshold, the electrode surface breaks down. Micro-discharges and breakdown create a vicious cycle of "contamination damage - micro-discharge - more severe contamination damage - more frequent micro-discharges," which continuously affects the stability of the deflection electric field and gradually leads to irreversible damage to the electrode plate. This problem is more pronounced under conditions of high beam current, heavy ion implantation, strong deflection electric fields, and long-term operation.

[0178] This scheme isolates the contamination and damage layers within the molybdenum protective layer. The protective layer achieves a stable and reliable equipotential connection to the electrode plate body via conductive pads and elastic conductive tracks, ensuring the entire beam-facing surface is at the same potential. The high molybdenum sputtering threshold of the protective layer makes sputtering more difficult, thus slowing the formation of the contamination and damage layers. Even if an arsenic-copper contamination layer is deposited on the surface of the molybdenum protective layer, only a weak potential difference exists between the protective layer and the electrode plate body, possibly due to non-ideal equipotentiality. The resulting charge accumulation region is weak and unstable, insufficient to cause micro-discharge. Furthermore, the protective layer, as a consumable component, is replaced periodically, removing the contamination and damage layers before they can accumulate into a stable charge accumulation region. Based on these factors, the conditions for micro-discharge formation are eliminated at the source, thus preventing arc erosion damage to the electrode surface and micro-discharge breakdown of the electrode surface. In addition, the flexible graphite conductive pad itself has good chemical stability and low outgassing rate, making it less prone to introducing new discharge risks due to its own degradation. Therefore, for high-current heavy (As + In ion implantation mode, this solution can effectively solve the micro-discharge and breakdown problems of traditional integral electrostatic deflection plates during long-term operation.

[0179] 3) Solve maintenance difficulties Traditional integrated electrostatic deflection plates require complete disassembly and reassembly for maintenance, which is time-consuming. In this solution, when the protective layer and corner pressure block surfaces become contaminated or suffer sputtering damage to a predetermined level, or when the conductive pads and flexible conductive rails need replacement, only the hexagonal countersunk screws need to be loosened, the corner pressure block removed, the old part pulled out, the new part replaced, and reinstalled. No operation on the electrode plate itself is required, significantly reducing maintenance time. The flexible conductive rails and conductive pads ensure the trapezoidal slot's stable pull-out performance and protect the electrodes on the bottom and side walls of the slot, maintaining slot accuracy even after multiple replacements. Therefore, the time for a single replacement operation is greatly reduced, significantly improving equipment utilization.

[0180] 4) Reduce costs While periodic offline chemical cleaning can temporarily alleviate electrode sputtering contamination in traditional monolithic electrostatic deflector plates, repeated chemical cleaning damages electrode surface precision, worsens surface roughness, and degrades electric field uniformity, leading to a gradual decrease in electrode performance. Even without timely cleaning, the electrodes are not completely faulty, and due to the high cost of replacement, users often choose to continue operating with contamination. This increases contamination in the vacuum chamber, ion beam, and even the wafer, further deteriorating ion implantation uniformity and reducing semiconductor chip performance and yield. Over time, the overall electrode plate material performance will continue to deteriorate until failure.

[0181] Under the effective protection of the composite protective layer, the sputtering and contamination experienced by the electrode plate body are significantly reduced, especially in the depth direction where the electrode plate body is protected from sputtering. Therefore, only the composite protective layer and elastic conductive tracks need to be replaced periodically according to actual usage, and the replacement cost of these spare parts is far lower than that of the integral electrode plate. Compared with Example 1, the molybdenum protective layer has a longer service life and a longer replacement cycle, which can reduce costs. The electrode plate body can be reused for a long time without frequent cleaning, which can significantly improve its service life and ensure long-term stable operation. Therefore, compared with the traditional integral electrostatic deflection plate, the electrostatic deflection plate with a replaceable protective structure of this invention significantly reduces the cost over its service life. Furthermore, contamination of the vacuum cavity, beam, and wafer is also reduced, which can effectively improve the performance and yield of semiconductor chips.

[0182] 5) The protective layer in the composite protective layer uses molybdenum (with a high sputtering threshold), which has excellent sputtering resistance. Therefore, the replaceable protective structure can effectively reduce sputtering contamination (especially metal particles) from the charged particle beam on the electrostatic deflector plate, thereby effectively mitigating the impact of sputtering contamination on the vacuum chamber walls, downstream beam elements, and wafer surfaces. This also improves beam performance and semiconductor chip yield. This beneficial effect is evident in this embodiment. + This is even more pronounced under low-energy, high-current heavy ion implantation conditions of 25 keV and 12 mA.

[0183] 4. Summary This solution is based on the design concept of functional separation and synergy. The electrostatic deflection plate is divided into a flexibly replaceable composite protective layer and the original integral electrode plate body. The composite protective layer consists of a molybdenum protective layer and a flexible graphite conductive pad, and an elastic conductive track is incorporated to synergistically achieve the flexible replaceability of the composite protective layer. The elastic conductive track itself also embodies the design concept of functional separation and synergy: the elastic copper alloy conductive track body focuses on radial electrical connection, while the beryllium copper spring focuses on providing elastic preload. Together, they achieve long-term stable and reliable radial contact and the flexible replaceability of the composite protective layer.

[0184] Because this embodiment uses a trapezoidal slot, the protective layer coverage on the beam-facing surface is more complete, and the protective layer has a high molybdenum sputtering threshold. The composite protective layer exhibits superior anti-sputtering performance, making it more suitable for the high-current heavy-duty (As) beams of this embodiment. + This solution utilizes ion implantation to more effectively address the problems of electric field distortion, micro-discharge and breakdown, maintenance difficulties, and high costs caused by ion sputtering contamination in traditional monolithic electrostatic deflector plates. It effectively ensures the long-term stability and service life of the electrostatic deflector plate itself, and also provides a guarantee for achieving higher doping precision and yield in semiconductor devices. The technical solution is simple, easy to process, and suitable for industrial application.

[0185] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A replaceable protective structure for an electrostatic deflection plate, comprising an electrode plate body, characterized in that, A slot is provided on the beam-facing surface of the electrode plate body, and a composite protective layer is provided in the slot. Along the beam transmission direction, the composite protective layer includes a retractable protective layer and a conductive pad from the outside to the inside. The conductive pad is located at the bottom of the slot, and the surface of the protective layer is basically flush with the beam-facing surface of the electrode plate body. A fitting gap is left between the side wall of the slot and the side wall of the protective layer and the side wall of the conductive pad. An elastic conductive track is provided on the side wall of the slot. The elastic conductive track crosses the fitting gap and contacts the side wall of the protective layer and the side wall of the conductive pad, thus acting as a bridge to connect the side wall of the protective layer and the side wall of the conductive pad with the side wall of the slot.

2. The replaceable protective structure according to claim 1, characterized in that: The slot and the electrode plate body have a common central axis of symmetry along the beam propagation direction. Both the slot and the electrode plate body are axisymmetric structures. The cross-section of the slot along the beam propagation direction is rectangular or trapezoidal with the opening width gradually narrowing along the beam propagation direction. The shape of the protective layer and conductive pad matches the shape of the slot.

3. The replaceable protective structure according to claim 2, characterized in that: The length or width of the slot located on the beam-facing surface of the electrode plate body accounts for 70%-86.5% of the length or width of the beam-facing surface of the electrode plate body, and the depth of the slot accounts for 5%-15% of the total length of the electrode plate body along the beam transmission direction.

4. The replaceable protective structure according to claim 1, characterized in that: The protective layer is made of graphite or molybdenum, and its thickness h1 accounts for 92%-97% of the slot depth.

5. The replaceable protective structure according to claim 1, characterized in that: The conductive pad is made of flexible graphite or conductive ceramic.

6. The replaceable protective structure according to claim 1, characterized in that: The elastic conductive track includes a metal conductive track body and a metal spring. A rectangular groove guide rail is provided on the side wall of the slot to accommodate the elastic conductive track. The metal spring is located at the bottom of the rectangular groove guide rail. The metal conductive track body is inserted into the rectangular groove guide rail, with one side in contact with the metal spring and the other side in contact with the protective layer. The metal conductive track body and the metal spring are made of conductive metal material.

7. The replaceable protective structure according to claim 6, characterized in that: At least one elastic conductive track is provided on each side wall of the slot. The initial cross section of the metal spring has a certain curvature, with the top of the curvature facing the side wall of the protective layer. After the metal conductive track body and the protective layer are installed into the rectangular groove guide rail of the side wall, the metal spring is basically flattened. The metal conductive track body is made of a material that is essentially the same as the electrode plate body and has elasticity, and is treated with self-lubrication. When the electrode plate body material is oxygen-free copper, the metal conductive track body material is made of an elastic copper alloy with a resistivity of 6.

10. -6 -1.5·10 -5 Ω·cm; When the electrode plate body material is aluminum alloy, the metal conductive track body material is also aluminum alloy with a resistivity of 4.10 Ω·cm; -6 -7·10 -6 Ω·cm; When the electrode plate body material is stainless steel, the metal conductive track body material is elastic stainless steel with a resistivity of 5.10 Ω·cm; -5 -1·10 -4 Ω·cm; The metal spring is made of a high-elasticity alloy that has undergone self-lubrication treatment, and its coefficient of thermal expansion is matched with the electrode plate body material and the metal conductive track body material.

8. The replaceable protective structure according to any one of claims 1-7, characterized in that: It also includes a pressure block, which is used to fix the protective layer to the electrode plate body and fill the mating gap between the sidewall of the slot and the sidewall of the protective layer adjacent to the facing surface of the electrode plate body.

9. The replaceable protective structure according to claim 8, characterized in that: The pressure block is a corner pressure block, with one side inserted into the fitting gap and the other side pressed on the protective layer. The pressure block and the protective layer are fixed to the electrode plate body by fasteners. The bottom of the corner pressure block inserted into the fitting gap has reserved space.

10. The replaceable protective structure according to any one of claims 1-7, characterized in that: The electrode plate body, conductive pads, elastic conductive tracks, and protective layer together constitute an equipotential body. The protective layer is connected to the electrode plate body along the beam transmission direction through the conductive pads, and the protective layer is connected to the electrode plate body radially through the elastic conductive tracks.

Images