A multi-stage electrode system for a high resolution high voltage ion source and a method of assembling the same

Abstract

The application discloses a multistage electrode system of a high-resolution high-voltage ion source and an assembling method thereof, relates to the technical field of high-voltage ion sources, and the aperture of the through hole in the center of each electrode arranged along the ion beam extraction direction is sequentially increased in the multistage electrode system to form an unobstructed optical field channel, so that non-contact visual fine alignment adjustment between the through holes of the multistage electrode can be realized via the optical field channel when the multistage electrode is assembled, and meanwhile, the flow-approaching surface of each rear-stage electrode of the ion source electrode is changed into a convex structure facing the ion source electrode direction, the spatial potential distribution is reshaped by using the inclined conductive boundary of the convex flow-approaching surface, the beam divergence side effect caused by the increase of the aperture of the through hole in the center of each rear-stage electrode of the ion source electrode is overcome, the emission degree of the ion beam can be reduced, the divergence angle can be reduced, and high-density ion beam can be focused and extracted with high quality.

Description

Technical Field

[0001] This application relates to the field of high-voltage ion source technology, and in particular to a multi-stage electrode system for a high-resolution high-voltage ion source and its assembly method. Background Technology

[0002] High-resolution ion beam equipment, represented by focused ion beam (FIB) systems, needs to achieve both sub-nanometer imaging resolution and fine processing capabilities. Its performance limit is highly dependent on the beam quality during the extraction stage of the high-voltage ion source.

[0003] The function of a high-voltage ion source is to emit ions from a tip and form an initial beam using a strong electric field. Currently, high-voltage ion sources generally employ a multi-stage electrode structure. For example, the most common three-stage electrode structure includes a cascaded ion source electrode, an extraction electrode, and a ground electrode. Each stage of the electrode has a central through-hole of the same diameter. After being extracted from the emission tip, ions pass through the central through-holes of each electrode in sequence to complete the initial beam formation. By combining the potentials and geometric configurations of the multi-stage electrodes, an acceleration-focusing field distribution can be constructed, achieving stable ion beam extraction.

[0004] The coaxiality between the multi-stage electrodes of a high-voltage ion source directly affects the ion beam quality. However, because the assembly of multi-stage electrodes in high-voltage ion sources typically employs a closed, stacked structure, adjusting the coaxiality during assembly is quite challenging. Currently, the mainstream approach involves assembly using complex three-coordinate measuring machines and external auxiliary tooling. However, relying on external flanges for stacking, multi-stage electrodes easily introduces accumulated tolerances from machining and assembly. Furthermore, external mechanical alignment often fails to visually reflect the true relative positions of the central through-holes of the multi-stage electrodes. In addition, the large spatial span between electrodes to meet high-voltage insulation requirements further increases the difficulty of precise alignment of the internal micro-apertures. These limitations result in suboptimal coaxiality between the multi-stage electrodes of existing high-voltage ion sources, affecting the divergence angle and transmission efficiency of the ion beam extracted from the high-voltage ion source, becoming one of the key bottlenecks restricting the development of domestically produced high-resolution ion beam equipment towards higher performance. Summary of the Invention

[0005] This application addresses the aforementioned problems and technical needs by proposing a multi-stage electrode system for a high-resolution high-voltage ion source and its assembly method. The technical solution of this application is as follows: In a first aspect, a multi-stage electrode system for a high-resolution high-voltage ion source is provided, the multi-stage electrode system of the high-resolution high-voltage ion source comprising a plurality of electrodes arranged sequentially along the ion beam extraction direction. Each electrode has a through hole at its center, with the center of the through hole coinciding with the center of the electrode. Each electrode center is located on the ion beam axis, and the aperture of the through holes on each electrode arranged along the ion beam extraction direction increases sequentially to form an unobstructed optical field of view channel. The ion source electrode is located at the foremost stage along the ion beam extraction direction, and the current-facing surfaces of all electrodes at the subsequent stages along the ion beam extraction direction bulge towards the ion source electrode.

[0006] A further technical solution is that the multi-stage electrode system of the high-resolution high-voltage ion source includes an ion source electrode, an extraction electrode, and a ground electrode arranged sequentially along the ion beam extraction direction, and the aperture of the first through-hole opened at the center of the ion source electrode is... The diameter of the second through hole opened at the center of the pole. The diameter of the third through hole opened at the center of the ground electrode satisfy ; The current-facing surface of the lead-out electrode bulges towards the ion source electrode, forming a conical structure with the center of the lead-out electrode as the apex and at least part of the current-facing surface as the side surface; The surface of the ground electrode bulges towards the ion source electrode, forming a conical structure with the center of the ground electrode as the apex and at least part of the surface of the ground electrode as the side.

[0007] A further technical solution is that the angle between the side generatrix and the bottom surface in the conical structure of the lead-out electrode is in the range of 20° to 70°, and the angle between the side generatrix and the bottom surface in the conical structure of the lead-out electrode is in the range of 20° to 70°.

[0008] A further technical solution involves adjusting the aperture ratio between the second through-hole at the center of the extraction electrode and the first through-hole at the center of the ion source electrode. Within the first proportional range, the aperture ratio between the third through hole opened at the center of the ground electrode and the second through hole opened at the center of the lead electrode. Within the second proportion range.

[0009] Its further technical solution is that the first ratio range is The second ratio range is .

[0010] A further technical solution involves the aperture of the first through-hole opened at the center of the ion source electrode. The range of values ​​is The aperture of the second through hole opened at the extreme center is drawn out. The range of values ​​is The diameter of the third through hole opened at the center of the ground electrode The range of values ​​is .

[0011] A method for assembling a multi-stage electrode system for a high-resolution high-voltage ion source, used for assembling a multi-stage electrode system as described in the first aspect, the method comprising: Multiple electrodes, including an ion source electrode, are fabricated. A through hole is opened at the center of each electrode, and the center of the through hole coincides with the center of the electrode. The diameter of the through hole on each electrode along the ion beam extraction direction increases sequentially. The flow-facing surface of the other electrodes, except for the ion source electrode, is convex. After the ion source electrode is fixedly assembled into the high-resolution high-voltage ion source, the other electrodes are sequentially fixedly assembled into the high-resolution high-voltage ion source along the ion beam extraction direction. When fixing each electrode, the protruding flow-facing surface of the electrode faces the side where the ion source electrode is located. Through the unobstructed optical field of view formed by the through holes on the current electrode and its predecessor electrode, the center of the current electrode is adjusted to be aligned with the center of the ion source electrode so that it is located on the ion beam axis before being fixedly assembled.

[0012] A further technical solution involves fabricating multiple electrodes, including an ion source electrode, a lead-out electrode, and a ground electrode, wherein the aperture of the first through-hole opened at the center of the ion source electrode is... The diameter of the second through hole opened at the center of the pole. The diameter of the third through hole opened at the center of the ground electrode satisfy Along the ion beam extraction direction, the other electrodes are sequentially fixed and assembled into the high-resolution high-voltage ion source, including: After the ion source electrode is fixedly assembled into the high-resolution high-voltage ion source, the current-facing surface of the lead electrode faces the ion source electrode. From the other side of the lead electrode relative to the ion source electrode, through the second through hole opened on the lead electrode, through the optical field channel formed by the second through hole in the center of the lead electrode and the first through hole in the center of the ion source electrode, adjust the center of the lead electrode to be aligned with the center of the ion source electrode, and then fix the lead electrode. After the lead electrode is fixedly assembled into the high-resolution high-voltage ion source, the current-facing surface of the ground electrode faces the lead electrode. From the other side of the ground electrode relative to the lead electrode, through the third through hole opened on the ground electrode, through the optical field channel formed by the third through hole in the center of the ground electrode and the second through hole in the center of the lead electrode, adjust the center of the ground electrode to be aligned with the center of the lead electrode, and then fix the ground electrode.

[0013] The further technical solution involves fabricating the ion source electrode, the extraction electrode, and the ground electrode separately, including: The ion source electrode adopts a flat plate electrode structure, the lead-out electrode adopts a conical structure with the center of the lead-out electrode as the apex and at least part of the flow-facing surface as the side surface, and the ground electrode adopts a conical structure with the center of the ground electrode as the apex and at least part of the flow-facing surface as the side surface. Determine the aperture based on the minimum visual angle of the optical field channel between the through holes of different electrode centers. Aperture Aperture ; Under the constraints of the operating voltage of the high-resolution high-voltage ion source and the aperture of the through holes on the three electrodes, the angle between the side generatrix and the bottom surface of the conical structure in the extraction electrode is determined. And the angle between the side generatrix and the bottom surface of the conical structure in the ground electrode. Simulation optimization was performed to obtain the structural parameters of the ion source electrode, the extraction electrode, and the ground electrode, respectively. Fabricated according to the structural parameters of the ion source electrode, and with a hole of a certain diameter opened in the center of the electrode. The first through-hole becomes the ion source electrode, which is fabricated according to the structural parameters of the lead-out electrode, and a hole with a certain diameter is opened in the center of the electrode. The second through hole is used to obtain the lead electrode, which is fabricated according to the structural parameters of the ground electrode, and a hole with a certain diameter is opened in the center of the electrode. The ground electrode is obtained through the third through hole.

[0014] A further technical solution involves adjusting the angle between the side generatrix and the bottom surface of the conical structure at the pole. And the angle between the side generatrix and the bottom surface of the conical structure in the ground electrode. Simulation optimization includes: With the included angle and included angle As the variable to be optimized, a simulation model of a multi-stage electrode system of a high-resolution high-voltage ion source is established. Based on the critical field strength condition of vacuum insulation withstand voltage under the working voltage of the high-resolution high-voltage ion source, the axial spacing range of the ion source electrode, the extraction electrode, and the ground electrode in the ion beam extraction direction is determined. Constrained by the axial spacing range between the ion source electrode, the lead electrode, and the ground electrode, a simulation model is used to... , The dynamics of charged particle beams were simulated using the included angle range to determine the beam extraction region under different included angle combinations. The curvature of the electrostatic equipotential surface under the given conditions is determined, and the combination of included angles that makes the curvature of the electrostatic equipotential surface reach the optimal convergence compensation state is determined. .

[0015] The beneficial technical effects of this application are: This application discloses a multi-stage electrode system for a high-resolution high-voltage ion source and its assembly method. In this multi-stage electrode system, the apertures of the through holes on each electrode arranged along the ion beam extraction direction are sequentially increased to form an unobstructed optical field of view. This allows for non-contact, visual, and precise alignment adjustment of the through holes during the assembly of the multi-stage electrodes via this optical field of view. Simultaneously, the flow-facing surfaces of each subsequent stage electrode of the ion source are modified to convex structures facing the ion source. The inclined conductive boundary of the convex flow-facing surface reshapes the spatial potential distribution, overcoming the beam divergence side effect caused by the increased aperture size of the central through holes of each subsequent stage electrode. By improving the aperture size of the central through holes of the multi-stage electrodes, this application enables the multi-stage electrode system to possess non-contact optical detection and alignment capabilities, improving the coaxiality after electrode assembly. Combined with the reshaping of the spatial electric field by the convex flow-facing structure, it can reduce the emissivity of the ion beam and decrease the divergence angle, achieving high-quality focusing and extraction of a high-density ion beam.

[0016] In this multi-stage electrode system, both the lead-out electrode and the ground electrode adopt a conical structure with the electrode center as the apex and at least part of the lead-out surface as the side. The edge of the through hole at the center of the electrode is closest to the ion source electrode to limit the core lead-out gap and ensure sufficient focusing electric field strength. The lead-out surface of the electrode extends and recedes outward and downward from the through hole at the center of the electrode, so that the spatial distance between the outer body of the electrode and the surrounding high-voltage structural components increases step by step. Without increasing the axial overall size, the outer high-voltage insulation space and surface creepage distance are greatly expanded. Thus, while ensuring a high electric field strength in the central area, the geometric receding naturally expands the outer high-voltage insulation clearance space, taking into account the high-voltage insulation reliability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the multi-stage electrode system in Embodiment 2 of this application.

[0018] Figure 2 This is a simulation example comparing the electric field line distribution simulation results when the lead-out electrode and ground electrode in a multi-stage electrode system adopt a traditional flat plate electrode structure, and when the lead-out electrode and ground electrode adopt a conical structure with a convex frontal surface.

[0019] Figure 3 This is another simulation example, showing a comparison of the simulation results of the equipotential field distribution and particle trajectory when the lead-out electrode and ground electrode in the multi-stage electrode system adopt the traditional flat plate electrode structure, and when the lead-out electrode and ground electrode adopt the conical structure with the convex frontal surface.

[0020] Figure 4 This is a flowchart illustrating the multi-stage electrode system method in Embodiment 4 of this application. Detailed Implementation

[0021] The specific embodiments of this application will be further described below with reference to the accompanying drawings.

[0022] Example 1 discloses a multi-stage electrode system for a high-resolution high-voltage ion source. The multi-stage electrode system includes multiple electrodes arranged sequentially along the ion beam extraction direction. These multiple electrodes include an ion source electrode and other electrodes. The ion source electrode is located at the foremost stage along the ion beam extraction direction, and the other electrodes are located at the stage after the ion source electrode along the ion beam extraction direction.

[0023] Each electrode has a through-hole at its center, with the center of the through-hole coinciding with the center of the electrode. To ensure the coaxiality of the assembly between the multi-stage electrodes, the diameter of the through-holes on each electrode along the ion beam extraction direction is progressively increased, thereby forming an unobstructed optical field of view channel from the outside in using the cascaded aperture size relationship. This optical field of view channel allows for easy adjustment to ensure that the centers of each electrode are located on the ion beam axis, thus improving the coaxiality of each stage of the electrode and ensuring high-quality focusing and extraction of the ion beam with a very small divergence angle.

[0024] In traditional multi-stage electrode systems, each electrode employs a planar electrode structure. While this application increases the aperture of the central through-hole of the post-ion source electrode to create an optical field channel for easier centering, it also causes the equipotential surface to severely collapse downstream. Physically, this is equivalent to introducing a diverging lens, which distorts the phase space trajectory of the ion flow, resulting in a larger virtual source size and severe beam divergence. Therefore, to avoid the negative impact of increasing the aperture of the central through-hole of the post-ion source electrode, this application optimizes the structure of each stage of electrodes located downstream of the ion source along the ion beam extraction direction. Instead of a planar electrode structure, it adopts a structure where the incoming surface bulges towards the ion source. The bulging incoming surface adjusts the spatial potential distribution through an inclined metallic conductive boundary, pushing back and flattening the equipotential surface that has severely collapsed into the hole due to the increased aperture. This physically counteracts the diverging lens effect introduced by the large aperture, maintaining the curvature of the focusing electric field in the beam extraction region.

[0025] In summary, this application increases the aperture of the central through-hole of the ion source's post-electrode, forming an optical field channel with progressively larger apertures. This allows the multi-stage electrode system to achieve non-contact optical alignment via this optical field channel, facilitating the adjustment of coaxiality between electrodes. This solves the drawbacks of blind adjustment in traditional closed structures and eliminates the cumulative tolerances in machining and stacking assembly caused by relying on external housing flange alignment. To compensate for the negative impact of the downstream equipotential surface depression caused by the increased aperture of the post-electrode's central through-hole, the post-electrode of the ion source is changed from a planar electrode structure to a structure with the flow-facing surface convex towards the ion source. The convex flow-facing surface reshapes the spatial electric field to compensate for the diverging lens effect caused by the increased aperture. By combining these two aspects, the curvature of the focusing electric field in the beam extraction region is optimized and maintained, reducing the divergence angle and emissivity of the ion beam, and achieving high-density beam focusing and extraction.

[0026] Example 2: The multi-stage electrode system in this example adopts a three-stage electrode structure, that is, as shown below... Figure 1 As shown, the multi-stage electrode system of this high-resolution high-voltage ion source includes an ion source electrode 110, an extraction electrode 120, and a ground electrode 130 arranged sequentially along the ion beam extraction direction. A first through-hole is formed at the center of the ion source electrode 110, a second through-hole is formed at the center of the extraction electrode 120, and a third through-hole is formed at the center of the ground electrode 130. The aperture of the first through-hole is... The diameter of the second through hole The diameter of the third through hole satisfy .

[0027] In this application, the ion source electrode 110 adopts a commonly used planar electrode structure, and a conical concave structure 111 with the first through hole as its apex is formed on the surface of the ion source electrode 110 near the lead-out electrode 120. The current-facing surface of the lead-out electrode 120 protrudes towards the ion source electrode 110, and the current-facing surface of the ground electrode 130 also protrudes towards the ion source electrode 110. In this embodiment, the current-facing protrusion structures of the lead-out electrode 120 and the ground electrode 130 are designed as follows: the current-facing surface of the lead-out electrode 120 protrudes towards the ion source electrode, forming a conical structure with the center of the lead-out electrode 120 as its apex and at least a portion of the current-facing surface as its side surface. Similarly, the current-facing surface of the ground electrode 130 protrudes towards the ion source electrode, forming a conical structure with the center of the ground electrode 130 as its apex and at least a portion of the current-facing surface as its side surface.

[0028] Based on this structure, the extractor 120 directly defines the short-distance beam acceleration extraction gap of the core with the edge of the second through-hole closest to the ion source electrode 110. At the same time, the conical structure of the extractor 120 extends and recedes smoothly from the second through-hole outwards and downwards, so that the spatial gap between the extractor 120 body and the high-voltage structure above gradually increases. Thus, while ensuring a high electric field strength in the central region, the geometric receding naturally expands the high-voltage insulation clearance space on the periphery.

[0029] To demonstrate the shaping effect of lead-out electrode 120 and ground electrode 130 on the spatial electric field, in a simulation example, under the condition that other conditions such as electrode aperture, operating voltage, and beam injection conditions are kept constant, and with lead-out electrode 120 and ground electrode 130 adopting a traditional flat plate electrode structure, the electric field intensity simulation results are as follows: Figure 2 As shown in (a), the electric field intensity simulation results for the electric field line distribution are obtained when the lead-out electrode 120 and the ground electrode 130 adopt a conical structure on the flow-facing surface. Figure 2 As shown in (b) above. Compare Figure 2 From (a) and (b), we can see that: When the lead electrode 120 and ground electrode 130 adopt a conventional planar electrode structure, this application increases the diameter of the second through hole at the center of the lead electrode 120. The equipotential surfaces, which should have been parallel, lost sufficient metallic boundary constraints. (Observation) Figure 2 As can be seen in region (a) of the central axis, the equipotential surface between the ion source electrode 110 and the lead-out electrode 120 is recessed inside the lead-out electrode 120 and in the direction of the ground electrode 130 (downstream of the beam). This recessed electric field shape physically constitutes a typical electrostatic diverging lens, which causes ions passing through it to be subjected to a radial thrust away from the central axis, thereby causing severe beam defocusing.

[0030] When the lead electrode 120 and the ground electrode 130 adopt a conical structure with an inclined convex shape facing the current-facing direction towards the ion source electrode 110, by Figure 2 As shown in (b), the inclined conductive boundary strongly shapes the spatial potential distribution, generating a compensating transverse electric field component and successfully pushing back the equipotential surface that was originally concave towards the downstream of the beam. Ultimately, the equipotential surface between the ion source electrode 110 and the extractor electrode 120 is shaped into a smooth arc that convexes towards the ion source electrode 110. This bowl-shaped equipotential surface, convex towards the ion source electrode 110 (facing the beam direction), constitutes a highly efficient electrostatic converging lens. The inward constraint force it generates perfectly counteracts the defocusing side effects caused by the large aperture, ensuring that the ion beam is focused and extracted with high quality at an extremely small divergence angle.

[0031] In another simulation example, under the condition that other conditions such as electrode aperture, operating voltage, and beam injection conditions are kept constant, and with the lead-out electrode 120 and ground electrode 130 adopting a traditional planar electrode structure, a charged particle beam dynamics simulation was performed. The simulation results of the equipotential field distribution and particle trajectory are as follows: Figure 3 As shown in (a), when the lead-out electrode 120 and the ground electrode 130 adopt a conical structure on the flow-facing surface, the simulation results of the equipotential field distribution and particle trajectory obtained by the charged particle beam dynamics simulation are as follows: Figure 3 As shown in (b) in the figure, Figure 3 The red portion represents the particle beam. (Comparison) Figure 3 From (a) and (b), we can see that: When the lead-in electrode 120 and the ground electrode 130 adopt a conventional planar electrode structure, due to their geometric symmetry constraints, an equipotential field distribution with negative curvature is formed in the lead-in region. This equipotential field distribution physically constitutes a diverging lens, causing ions to experience outward radial repulsion when leaving the lead-in electrode aperture region, resulting in secondary divergence of the beam. Figure 3 As shown in (a) of the diagram.

[0032] When the lead-out electrode 120 and the ground electrode 130 adopt a conical structure with an inclined convex shape facing the current-facing direction towards the ion source electrode 110, such as Figure 3 As shown in (b), the equipotential field of the extraction region is actively shaped into a bowl-shaped structure convex toward the ion source electrode 110 by designing a conical electrode boundary. This morphology utilizes the geometric compensation effect of electrostatic force to construct a highly efficient electrostatic converging lens in the extraction region. The simulation trajectory diagram clearly shows that after passing through the second through-hole at the center of the extraction electrode 120, the ion beam rapidly converges and maintains parallel laminar flow characteristics, effectively offsetting the defocusing side effects caused by the large through-hole geometry.

[0033] It should be noted that the dimensions of the conical concave structure 111 on the surface of the ion source electrode 110 near the lead-out electrode 120 are determined based on the withstand voltage distance constraint between it and the lead-out electrode 120. Therefore, in the above... Figure 2 and Figure 3 In the simulation examples, under the same withstand voltage distance constraint between the ion source electrode 110 and the lead-out electrode 120, when the lead-out electrode 120 and the ground electrode 130 adopt a conical structure with a convex, inclined surface facing the ion source electrode 110, the size of the conical concave structure 111 of the ion source electrode 110 is larger than when the lead-out electrode 120 and the ground electrode 130 adopt a flat electrode structure. Figure 2 The structure of the ion source 110 in (a) and (b) shows that Figure 3 Similarly.

[0034] As can be seen from the two comparative simulation examples above, the conical structure with an inclined convex shape facing the ion source electrode 110 on the front surface of the lead-in electrode 120 and the ground electrode 130 in this application can effectively suppress defocusing and optimize the extraction quality. However, for both the lead-in electrode 120 and the ground electrode 130, when the angle between the side generatrix and the bottom surface of the conical structure of the front surface is greater than 70°, the conical structure of the front surface is too gentle and approaches that of a traditional planar electrode. This results in an insufficiently weak electric field component generated in the radial (lateral) direction, which cannot penetrate and cover the axial region of the large aperture. The equipotential surface will still collapse downstream of the beam, resulting in severe beam divergence and an increased virtual source. When the angle between the side generatrix and the bottom surface of the conical structure of the front surface is less than 20°, the conical structure of the front surface is too sharp. This will cause excessive focusing of the local electric field at the axis, resulting in excessive convergence or arcing risks, and will also severely compress the surrounding assembly space. Therefore, in another embodiment, the angle between the side generatrix and the bottom surface in the conical structure of the frontal surface of the pole 120 is drawn out. The value ranges from 20° to 70°, and the angle between the side generatrix and the bottom surface of the conical structure on the flow-facing side of the ground electrode 130 is [value range missing]. The value ranges from 20° to 70°, thus ensuring that the curvature of the equipotential surface reaches the optimal convergence compensation state, with the included angle... and included angle The values ​​can be equal or unequal.

[0035] Furthermore, to better maintain the focusing electric field curvature of the conical electrostatic convergence electric field generated by the lead-in electrode 120 and the ground electrode 130, thereby better compensating for the diverging lens effect caused by aperture enlargement and optimizing the ion beam quality, in one embodiment, the apertures of the central through-holes of adjacent electrodes satisfy a proportional constraint, including: the aperture ratio between the second through-hole at the center of the lead-in electrode 120 and the first through-hole at the center of the ion source electrode 110. Within the first proportional range, and the aperture ratio between the third through hole at the center of the ground electrode 130 and the second through hole at the center of the lead electrode 120. Within the second proportional range. In another embodiment, the first proportional range is... The second ratio range is .

[0036] In another embodiment, in addition to satisfying the above-mentioned increasing aperture relationship, the aperture of the first through hole on the three electrodes is... The value itself must also meet the requirements of plasma extraction current intensity and initial virtual source size. Additionally, the diameter of the second through-hole... It also needs to meet the requirement of effective penetration depth for the converging field generated by the lead-in electrode 120, and the aperture... If the aperture is too large, the electric field may not be able to cover the axis, resulting in a loss of focusing ability. Taking all factors into consideration, in one embodiment, the aperture of the first through-hole at the center of the ion source 110 is... The range of values ​​is The aperture of the second through hole opened at the center of pole 120 is revealed. The range of values ​​is The diameter of the third through hole opened at the center of ground electrode 130 The range of values ​​is .

[0037] Example 3 further discloses a method for assembling a multi-stage electrode system for a high-resolution high-voltage ion source. This method is used to fix and assemble the multi-stage electrode systems described in the above embodiments into a high-resolution high-voltage ion source. The method includes the following steps: Multiple electrodes, including an ion source electrode, are fabricated. A through hole is opened at the center of each electrode, and the center of the through hole coincides with the center of the electrode. The diameter of the through hole on each electrode along the ion beam extraction direction increases sequentially. The flow-facing surface of the other electrodes, except for the ion source electrode, is convex.

[0038] First, the ion source electrode is fixedly assembled into the high-resolution high-voltage ion source. Then, along the ion beam extraction direction, the other electrodes are sequentially fixedly assembled into the high-resolution high-voltage ion source. When fixing each electrode except the ion source electrode, the protruding flow-facing surface of the electrode is facing the side where the ion source electrode is located. Through the unobstructed optical field of view formed by the current electrode and the through-hole on the preceding electrode along the ion beam extraction direction, the center of the current electrode is adjusted to be aligned with the center of the ion source electrode so that it is located on the ion beam axis, and then the electrode is fixedly assembled. It should be noted that the axial position of each electrode in the ion beam extraction direction is generally predetermined. In this embodiment, when assembling each electrode, the electrode position is mainly adjusted on a plane perpendicular to the ion beam axis.

[0039] This application increases the diameter of the central through-hole of the post-electrode of the ion source to form an optical field channel with progressively larger apertures. This allows the assembly position of the electrodes to be adjusted through the unobstructed optical field channel during the assembly of each stage of the electrodes, thereby improving the coaxiality between the multi-stage electrodes.

[0040] Example 4: In this example, when the multi-stage electrode system of the high-resolution high-voltage ion source adopts a three-stage electrode structure, the assembly method of the multi-stage electrode system includes the following steps, please refer to... Figure 4 Flowchart: Step 410: The ion source electrode 110, the lead electrode 120, and the ground electrode 130 are fabricated respectively.

[0041] The ion source electrode 110 fabricated in this step has a first through hole in its center, the lead electrode 120 has a second through hole in its center, and the ground electrode 130 has a third through hole in its center. The diameter of the first through hole is... The diameter of the second through hole The diameter of the third through hole satisfy .

[0042] In another embodiment, fabricating the ion source 110, the lead-out electrode 120, and the ground electrode 130 includes the following steps: (1) First, determine the structure of each electrode. In this embodiment, the ion source electrode 110 follows the existing classic planar electrode structure. In order to compensate for the influence of the increased aperture of the through hole on the lead electrode 120 and the ground electrode 130, the lead electrode 120 adopts a conical structure with the center of the lead electrode as the apex and at least part of the flow-facing surface as the side surface, and the ground electrode 130 adopts a conical structure with the center of the ground electrode as the apex and at least part of the flow-facing surface as the side surface.

[0043] (2) Determine the aperture based on the minimum visual angle of the optical field channel between the through holes of different electrode centers. Aperture Aperture The diameter of the through-hole on each electrode needs to be within the corresponding range, and the ratio of the diameters of the through-holes on adjacent electrodes also needs to be within the corresponding ratio range. This constraint can be referred to in the description of Embodiment 2 above, and will not be repeated here.

[0044] (3) As described in the above embodiment, the angle between the inclined generatrix of the conical structure of the lead-out electrode 120 and the ground electrode 130 and the bottom surface has a direct impact on the shaping effect of the equipotential surface. When the angle is too large, the shaping effect of the equipotential surface is limited. When the angle is too small, it will cause the local electric field at the axis to be over-focused.

[0045] In one approach, the included angle can be determined empirically within a range of 20° to 70°. and included angle However, to achieve a better equipotential surface shaping effect, in another embodiment, under the constraints of the operating voltage of the high-resolution high-voltage ion source and the aperture of the through holes on the three electrodes, the angle between the side generatrix and the bottom surface of the conical structure in the lead-out electrode is adjusted. And the angle between the side generatrix and the bottom surface of the conical structure in the ground electrode. Simulation optimization was performed to obtain the structural parameters of the ion source electrode, the extraction electrode, and the ground electrode. The main purpose of this simulation optimization process was to determine the included angle. and included angle Apart from these two included angles, other structural parameters of the ion source electrode, the lead-out electrode, and the ground electrode can be determined in advance according to the application requirements of the high-resolution high-voltage ion source, including the circumferential dimensions of the electrodes, the electrode thickness, the electrode material, and the axial installation position of each electrode in the ion beam lead-out direction. This part is designed and determined according to the actual situation with reference to existing methods, and this application does not limit it.

[0046] Specifically, using the included angle and included angle As variables to be optimized, a simulation model of a multi-stage electrode system for a high-resolution high-voltage ion source is established based on other structural parameters of the ion source electrode, the extraction electrode, and the ground electrode, as well as the axial installation position.

[0047] Based on the critical field strength condition of vacuum insulation withstand voltage under the working voltage of the high-resolution high-voltage ion source, the axial spacing range of the ion source electrode 110, the lead electrode 120 and the ground electrode 130 in the ion beam extraction direction is determined. This part refers to the existing method for coordinated constraint, which will not be elaborated here.

[0048] Then, using the axial spacing range between the ion source electrode 110, the lead electrode 120, and the ground electrode 130 as constraints, the established simulation model was used to... , The dynamics of charged particle beams were simulated within the range of included angle values, and the beam extraction region was calculated using three-dimensional electrostatic field simulation software under different included angle combinations. The curvature of the electrostatic equipotential surface under the given conditions is determined, and the combination of included angles that makes the curvature of the electrostatic equipotential surface reach the optimal convergence compensation state is determined. .

[0049] (4) Finally, the electrode is fabricated according to the structural parameters of the ion source electrode 110 and a hole with a certain diameter is opened in the center of the electrode. The first through-hole yields the ion source electrode 110. It is fabricated according to the structural parameters of the lead-out electrode 120, and a hole with a specific diameter is formed at the center of the electrode. The second through hole leads to the lead electrode 120. It is fabricated according to the structural parameters of the ground electrode 130, and a hole with a certain diameter is opened at the center of the electrode. The third through hole provides the ground electrode 130.

[0050] Step 420: The ion source electrode 110 is fixedly assembled into the high-resolution high-voltage ion source. The specific assembly position is determined according to the actual structure of the high-resolution high-voltage ion source. After the ion source electrode 110 is assembled, the ion beam axis can be determined. This ion beam axis passes through the center of the ion source electrode 110 and is perpendicular to the planar electrode structure of the ion source electrode 110.

[0051] Step 430: After fixing the ion source electrode 110 into the high-resolution high-voltage ion source, the current-facing surface of the lead-out electrode 120 is oriented towards the ion source electrode 110. This is because the diameter of the second through-hole opened at the center of the lead-out electrode 120... Therefore, the second through-hole at the center of the lead-out electrode 120 and the first through-hole at the center of the ion source electrode 110 form an unobstructed optical detection path from the outside to the inside. The relative position of the center of the lead-out electrode 120 and the center of the ion source electrode 110 can be adjusted through the second through-hole on the lead-out electrode 120 from the other side of the lead-out electrode 120 relative to the ion source electrode 110, via this optical field channel, until the center of the lead-out electrode 120 and the center of the ion source electrode 110 are aligned, and then the lead-out electrode 120 is fixedly assembled. Since the center of the lead-out electrode 120 is aligned with the center of the ion source electrode 110, the assembled center of the lead-out electrode 120 is also located on the ion beam axis, and when the flow-facing surface of the lead-out electrode 120 adopts a conical structure, the axis of its flow-facing conical structure coincides with the ion beam axis.

[0052] Step 440: After fixing the lead-out electrode 120 into the high-resolution high-voltage ion source, the current-facing surface of the ground electrode 130 is oriented towards the lead-out electrode 120. This is because the aperture of the third through-hole opened at the center of the ground electrode 130... Therefore, the third through-hole at the center of the ground electrode 130 and the second through-hole at the center of the lead-in electrode 120 form an unobstructed optical detection path from the outside in. The relative position of the center of the ground electrode 130 and the center of the lead-in electrode 120 can be adjusted through the third through-hole on the ground electrode 130 from the other side of the ground electrode 130 relative to the lead-in electrode 120, via this optical field channel, until the center of the ground electrode 130 and the center of the lead-in electrode 120 are aligned, and then the ground electrode 130 is fixedly assembled. Since the center of the ground electrode 130 is aligned with the center of the lead-in electrode 120, and the center of the lead-in electrode 120 is located on the ion beam axis, the assembled center of the ground electrode 130 is also located on the ion beam axis. Furthermore, when the incoming surface of the ground electrode 130 adopts a conical structure, the axis of its incoming conical structure coincides with the ion beam axis.

[0053] In this embodiment, when assembling each stage of electrodes sequentially, the center of each stage electrode is aligned with the center of the previous stage electrode. This step-by-step alignment assembly method enables good electrode coaxiality even when the axial distance between each stage electrode is large in a high-resolution high-voltage ion source.

[0054] The above descriptions are merely preferred embodiments of this application, and this application is not limited to the above embodiments. It is understood that other improvements and variations that can be directly derived or conceived by those skilled in the art without departing from the spirit and concept of this application should be considered to be included within the protection scope of this application.

Claims

1. A multi-stage electrode system for a high-resolution high-voltage ion source, characterized in that, The multi-stage electrode system of the high-resolution high-voltage ion source includes multiple electrodes arranged sequentially along the ion beam extraction direction. Each electrode has a through hole at its center, with the center of the through hole coinciding with the center of the electrode. Each electrode center is located on the ion beam axis, and the aperture of the through holes on each electrode arranged along the ion beam extraction direction increases sequentially to form an unobstructed optical field of view channel. The ion source electrode is located at the foremost stage along the ion beam extraction direction, and the current-facing surfaces of all electrodes at the subsequent stages along the ion beam extraction direction bulge towards the ion source electrode.

2. The multi-stage electrode system of the high-resolution high-voltage ion source according to claim 1, characterized in that, The multi-stage electrode system of the high-resolution high-voltage ion source includes an ion source electrode, an extraction electrode, and a ground electrode arranged sequentially along the ion beam extraction direction. The aperture of the first through-hole opened at the center of the ion source electrode is... The diameter of the second through hole opened at the center of the pole. The diameter of the third through hole opened at the center of the ground electrode satisfy ; The current-facing surface of the lead-out electrode bulges towards the ion source electrode, forming a conical structure with the center of the lead-out electrode as the apex and at least part of the current-facing surface as the side surface; The surface of the ground electrode bulges towards the ion source electrode, forming a conical structure with the center of the ground electrode as the apex and at least part of the surface of the ground electrode as the side.

3. The multi-stage electrode system of the high-resolution high-voltage ion source according to claim 2, characterized in that, The angle between the side generatrix and the bottom surface of the lead-out electrode's conical structure on the flow-facing side ranges from 20° to 70°, and the angle between the side generatrix and the bottom surface of the ground electrode's conical structure on the flow-facing side ranges from 20° to 70°.

4. The multi-stage electrode system of the high-resolution high-voltage ion source according to claim 2, characterized in that, The aperture ratio between the second through-hole at the center of the lead-out electrode and the first through-hole at the center of the ion source electrode Within the first proportional range, the aperture ratio between the third through hole opened at the center of the ground electrode and the second through hole opened at the center of the lead electrode. Within the second proportion range.

5. The multi-stage electrode system of the high-resolution high-voltage ion source according to claim 4, characterized in that, The first ratio range is The second ratio range is .

6. The multi-stage electrode system of the high-resolution high-voltage ion source according to claim 2, characterized in that, The aperture of the first through hole opened at the center of the ion source electrode The range of values ​​is The aperture of the second through hole opened at the extreme center is drawn out. The range of values ​​is The diameter of the third through hole opened at the center of the ground electrode The range of values ​​is .

7. A method for assembling a multi-stage electrode system for a high-resolution high-voltage ion source, characterized in that, For assembling the multi-stage electrode system as described in any one of claims 1-6, the assembly method of the multi-stage electrode system of the high-resolution high-voltage ion source includes: Multiple electrodes, including an ion source electrode, are fabricated. A through hole is opened at the center of each electrode, and the center of the through hole coincides with the center of the electrode. The diameter of the through hole on each electrode along the ion beam extraction direction increases sequentially. The flow-facing surface of the other electrodes, except for the ion source electrode, is convex. After the ion source electrode is fixedly assembled into the high-resolution high-voltage ion source, the other electrodes are sequentially fixedly assembled into the high-resolution high-voltage ion source along the ion beam extraction direction. When fixing each electrode, the protruding flow-facing surface of the electrode faces the side where the ion source electrode is located. Through the unobstructed optical field of view channel formed by the through holes on the current electrode and its predecessor electrode, the center of the current electrode is adjusted to be aligned with the center of the ion source electrode so that it is located on the ion beam axis before being fixedly assembled.

8. The assembly method of the multi-stage electrode system of the high-resolution high-voltage ion source according to claim 7, characterized in that, The fabricated electrodes include an ion source electrode, a lead-out electrode, and a ground electrode. The aperture of the first through-hole opened at the center of the ion source electrode is... The diameter of the second through hole opened at the center of the pole. The diameter of the third through hole opened at the center of the ground electrode satisfy ; The other electrodes are sequentially fixed and assembled into the high-resolution high-voltage ion source along the ion beam extraction direction, including: After the ion source electrode is fixedly assembled into the high-resolution high-voltage ion source, the current-facing surface of the lead electrode faces the ion source electrode. From the other side of the lead electrode relative to the ion source electrode, through the second through hole opened on the lead electrode, through the optical field channel formed by the second through hole in the center of the lead electrode and the first through hole in the center of the ion source electrode, adjust the center of the lead electrode to be aligned with the center of the ion source electrode, and then fix the lead electrode. After the lead electrode is fixedly assembled into the high-resolution high-voltage ion source, the current-facing surface of the ground electrode faces the lead electrode. From the other side of the ground electrode relative to the lead electrode, through the third through hole opened on the ground electrode, through the optical field channel formed by the third through hole in the center of the ground electrode and the second through hole in the center of the lead electrode, adjust the center of the ground electrode to be aligned with the center of the lead electrode, and then fix the ground electrode.

9. The assembly method of the multi-stage electrode system of the high-resolution high-voltage ion source according to claim 8, characterized in that, The ion source electrode, extraction electrode, and ground electrode were fabricated separately, including: The ion source electrode adopts a flat plate electrode structure, the lead-out electrode adopts a conical structure with the center of the lead-out electrode as the apex and at least part of the flow-facing surface as the side surface, and the ground electrode adopts a conical structure with the center of the ground electrode as the apex and at least part of the flow-facing surface as the side surface. Determine the aperture based on the minimum visual angle of the optical field channel between the through holes of different electrode centers. Aperture Aperture ; Under the constraints of the operating voltage of the high-resolution high-voltage ion source and the aperture of the through holes on the three electrodes, the angle between the side generatrix and the bottom surface of the conical structure in the extraction electrode is determined. And the angle between the side generatrix and the bottom surface of the conical structure in the ground electrode. Simulation optimization was performed to obtain the structural parameters of the ion source electrode, the extraction electrode, and the ground electrode, respectively. Fabricated according to the structural parameters of the ion source electrode, and with a hole of a certain diameter opened in the center of the electrode. The first through-hole becomes the ion source electrode, which is fabricated according to the structural parameters of the lead-out electrode, and a hole with a certain diameter is opened in the center of the electrode. The second through hole is used to obtain the lead electrode, which is fabricated according to the structural parameters of the ground electrode, and a hole with a certain diameter is opened in the center of the electrode. The ground electrode is obtained through the third through hole.

10. The assembly method of the multi-stage electrode system of the high-resolution high-voltage ion source according to claim 9, characterized in that, The angle between the side generatrix and the bottom surface of the conical structure in the lead-out pole And the angle between the side generatrix and the bottom surface of the conical structure in the ground electrode. Simulation optimization includes: With the included angle and included angle As the variable to be optimized, a simulation model of a multi-stage electrode system of a high-resolution high-voltage ion source is established. Based on the critical field strength condition of vacuum insulation withstand voltage under the working voltage of the high-resolution high-voltage ion source, the axial spacing range of the ion source electrode, the extraction electrode, and the ground electrode in the ion beam extraction direction is determined. Constrained by the axial spacing range between the ion source electrode, the lead electrode, and the ground electrode, the simulation model is used in... , The dynamics of charged particle beams were simulated using the included angle range to determine the beam extraction region under different included angle combinations. The curvature of the electrostatic equipotential surface under the given conditions is determined, and the combination of included angles that makes the curvature of the electrostatic equipotential surface reach the optimal convergence compensation state is determined. .

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