A method of self-calibrating manufacturing of an electron beam objective lens deflection assembly

Abstract

The embodiment of the application provides a kind of electron beam objective lens deflection component self-calibration manufacturing method, it is related to the manufacturing technical field of precision electron optics equipment, method includes winding excitation coil to form electromagnetic lens outside iron core;Installation stator assembly and rotor end plate;Stator assembly is installed in objective lens connecting tube inside;Install adjustable deflector component with eccentricity adjusting ring and M3 precision adjusting screw, adjustable deflector component includes deflector diaphragm and 8 levels of arc-shaped sub-electrode of uniform distribution;Electromagnetic lens is detected to magnetic field center;According to the detection result, M3 precision adjusting screw is controlled by computer closed loop feedback, the position of adjustable deflector component is automatically adjusted, so that electron optical axis and magnetic field center axis coincide;Locking component and carrying out packaging.The application has the effects of high self-calibration precision and high magnetic field uniformity.

Description

Technical Field

[0001] This invention relates to the field of precision electro-optical equipment technology, and in particular to a self-calibration manufacturing method for an electron beam objective lens deflection assembly. Background Technology

[0002] In scanning electron microscopes, electron beam exposure systems, and electron beam processing equipment, the focusing and scanning control of the electron beam depends on the electromagnetic objective and deflector assembly. The electromagnetic objective is responsible for focusing, and the deflector is responsible for controlling the scanning direction. The consistency of their axes directly determines the electron beam resolution and scanning accuracy.

[0003] In existing technologies, electromagnetic objectives and deflectors are mostly separate components, and coaxial installation is achieved through mechanical assembly. However, there is a deviation between the magnetic field center of the electromagnetic lens and the mechanical center, and assembly requires repeated manual adjustments, resulting in low efficiency and difficulty in controlling coaxiality. Traditional iron cores are mostly integrated or simply spliced ​​together, which easily leads to magnetic flux leakage and eddy current loss, and poor magnetic field uniformity.

[0004] To address the aforementioned issues, there is an urgent need for a self-calibration method that automatically detects the center of the magnetic field and adjusts the position of the deflector in real time during the manufacturing process, in order to achieve high-precision integration. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a self-calibration manufacturing method for an electron beam objective lens deflection assembly.

[0006] The self-calibration manufacturing method for an electron beam objective lens deflection assembly provided in this application adopts the following technical solution: A self-calibration manufacturing method for an electron beam objective lens deflection assembly includes the following steps: S1. Construct an interlocking iron core; S2. An electromagnetic lens is formed by winding an excitation coil on the outside of the iron core. S3. Install the stator assembly and rotor end plate; S4. Install the stator assembly inside the objective lens connecting tube; S5. Install an adjustable deflector assembly with an eccentric adjustment ring and 3 sets of M3 precision adjustment screws. The adjustable deflector assembly includes a deflector aperture and 8 uniformly distributed arc-shaped sub-electrodes. The sub-electrodes are fixed to the eccentric adjustment ring by ceramic insulating pillars. S6. Detect the center of the magnetic field of the electromagnetic lens; S7. Based on the test results, the position of the adjustable deflector assembly is automatically adjusted by controlling the three sets of M3 precision adjusting screws on the eccentric adjustment ring through computer closed-loop feedback, so that the electron optical axis coincides with the magnetic field center axis. S8. Lock the component and encapsulate it.

[0007] Optionally, the staggered block core consists of two layers of fan-shaped blocks, which are staggered by 22.5° along the circumferential direction.

[0008] Optionally, the excitation coil adopts a symmetrical grouping winding method, with a total number of 320-500 turns.

[0009] Optionally, the magnetic field center detection uses a Hall sensor array or an electron beam probe, and a low current of 0.3-0.5A is applied to the excitation coil during detection.

[0010] Optionally, the deflector assembly includes eight uniformly distributed arc-shaped sub-electrodes.

[0011] Optionally, the eccentric adjustment ring is made of aluminum alloy with an eccentricity of 0.1 mm. It has three sets of M3 precision adjustment screws arranged at 120° intervals and connected to a computer closed-loop feedback system to achieve automatic fine adjustment of 0-200 μm in the X / Y direction.

[0012] In summary, this application includes at least one of the following beneficial technical effects: High self-calibration accuracy: Automatic alignment is achieved through magnetic field detection and closed-loop fine-tuning mechanism, improving coaxiality; High magnetic field uniformity: The 22.5° staggered block structure eliminates magnetic flux leakage, reduces eddy current loss, and improves magnetic field uniformity; High assembly efficiency: Modularization and self-calibration are completed in one step, shortening the assembly time of a single part. Attached Figure Description

[0013] Figure 1 This is the overall flowchart of this method. Detailed Implementation

[0014] The terminology used in the following embodiments is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to also include expressions such as “one or more,” unless the context clearly indicates otherwise. It should also be understood that in the following embodiments of this application, “at least one” and “one or more” refer to one, two, or more than two. The term “and / or” is used to describe the relationship between related objects, indicating that three relationships may exist; for example, A and / or B can indicate: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character “ / ” generally indicates that the preceding and following related objects are in an “or” relationship.

[0015] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0016] The following is in conjunction with the appendix Figure 1 The present invention will be described in further detail below.

[0017] This application discloses a self-calibration manufacturing method for an electron beam objective lens deflection assembly, referring to... Figure 1 This includes the following steps: S1. Construction of modular iron core: Silicon steel sheets are stamped into 8 fan-shaped iron core blocks with a central angle of 45°. Each block has 2 positioning holes at the end. First, they are spliced ​​together to form the first layer of annular iron core, which is fixed with through screws. Then, the second layer is stacked. The second layer of blocks is offset from the first layer by 22.5° along the circumference to form an interlaced magnetic circuit structure.

[0018] S2. Stator winding to form an electromagnetic lens: Using a modular iron core as the skeleton, symmetrical grouping is used for winding on the outer wall. The excitation coil is wound using 4 main excitation coils and 4 auxiliary excitation coils, with a total of 320-500 turns, using 0.5mm diameter enameled copper wire; potting and curing with insulating resin.

[0019] S3. Stator assembly installation: Install a non-magnetic aluminum alloy rotor end plate on the upper end of the stator and fix it with 4 M6 bolts.

[0020] S4. Objective lens connecting tube installation: Install the stator assembly into the objective lens connecting tube and secure it with 8 M5 bolts on the upper flange.

[0021] S5. Pre-installed deflector assembly: The deflector aperture and 8-stage arc-shaped sub-electrode are installed on the inner wall of the lower end of the objective lens connecting tube; the sub-electrode is installed on an adjustable mounting base with an eccentric adjustment ring, and 3 sets of M3 precision adjustment screws can achieve 0-200μm fine adjustment in the X / Y direction.

[0022] S6. Magnetic field center detection: A low current of 0.3-0.5A is passed through the excitation coil to form an initial magnetic field, and the position of the magnetic field center is detected in real time using a Hall sensor array or electron beam probe integrated on the cylinder wall.

[0023] S7. Electro-optical axis self-calibration adjustment: The computer collects the coordinates of the magnetic field center and controls the precision screws on the adjustable mounting base of the deflector through closed-loop feedback to automatically fine-tune the position of the deflector aperture and sub-electrode, so that the deviation between the electron optical axis and the magnetic field center is ≤3μm.

[0024] S8. Locking and Sealing: After calibration, tighten the adjusting screws and all fasteners, and perform vacuum sealing on the components.

[0025] In a preferred embodiment: The core is made of 100mm outer diameter and 50mm inner diameter, with two layers of silicon steel sheets, each 0.5mm thick, and the excitation coil has a total of 320 turns. The adjustable mounting base for the deflector uses an aluminum alloy eccentric adjustment ring with an eccentricity of 0.1mm. Three sets of M3 precision adjustment screws with a 120° spacing allow for fine-tuning. When detecting the center of the magnetic field, a 0.3A current is applied, the Hall array collects the data, the computer calculates the deviation and outputs a pulse to the stepper motor to drive the screw for adjustment until the deviation is <3μm. After calibration, the torque locking screw is vacuum sealed. After testing, the finished product has a magnetic field strength ≥0.6T and a controllable deflection angle of ±5°, which is suitable for SEM with a resolution of 0.8nm.

[0026] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Any equivalent modifications or variations made by those skilled in the art based on the content disclosed in the present invention should be included within the scope of protection set forth in the claims.

Claims

1. A method for manufacturing a self-calibration assembly for an electron beam objective lens deflection module, characterized in that, Includes the following steps: S1. Construct an interlocking iron core; S2. An electromagnetic lens is formed by winding an excitation coil on the outside of the iron core. S3. Install the stator assembly and rotor end plate; S4. Install the stator assembly inside the objective lens connecting tube; S5. Install an adjustable deflector assembly with an eccentric adjustment ring and 3 sets of M3 precision adjustment screws. The adjustable deflector assembly includes a deflector aperture and 8 uniformly distributed arc-shaped sub-electrodes. The sub-electrodes are fixed to the eccentric adjustment ring by ceramic insulating pillars. S6. Detect the center of the magnetic field of the electromagnetic lens; S7. Based on the test results, the position of the adjustable deflector assembly is automatically adjusted by controlling the three sets of M3 precision adjusting screws on the eccentric adjustment ring through computer closed-loop feedback, so that the electron optical axis coincides with the magnetic field center axis. S8. Lock the component and encapsulate it.

2. The self-calibration manufacturing method for an electron beam objective lens deflection assembly according to claim 1, characterized in that: The staggered block core consists of two layers of fan-shaped blocks, which are staggered by 22.5° along the circumference.

3. The self-calibration manufacturing method for an electron beam objective lens deflection assembly according to claim 1, characterized in that: The excitation coil adopts a symmetrical grouping winding method, with a total number of 320-500 turns.

4. The self-calibration manufacturing method for an electron beam objective lens deflection assembly according to claim 1, characterized in that: The magnetic field center detection uses a Hall sensor array or an electron beam probe, and a low current of 0.3-0.5A is applied to the excitation coil during detection.

5. The self-calibration manufacturing method for an electron beam objective lens deflection assembly according to claim 1, characterized in that: The deflector assembly includes eight uniformly distributed arc-shaped sub-electrodes.

6. The self-calibration manufacturing method for an electron beam objective lens deflection assembly according to claim 1, characterized in that: The eccentric adjustment ring is made of aluminum alloy with an eccentricity of 0.1mm. It has three sets of M3 precision adjustment screws arranged at 120° intervals and connected to a computer closed-loop feedback system to achieve automatic fine adjustment of 0-200μm in the X / Y direction.

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