A laser processing method and system for narrow-pitch discrete tombstone array circuits

Abstract

This invention discloses a laser processing method and system for narrow-pitch discrete tombstone array circuits, relating to the field of laser three-dimensional processing technology. The laser processing method is as follows: First, a metal thin film is deposited over the entire discrete tombstone array sample; then, the three-dimensional curved surface is discretized into several sub-regions according to the incident angle tolerance threshold and a representative incident angle is assigned; an incident angle-wavefront compensation database is constructed, generating a set of collaborative processing parameters including a spatial light modulator compensation phase map, energy compensation parameters, and dynamic focusing parameters; finally, processing is performed sequentially according to the sub-regions, adjusting the workpiece posture through a multi-axis linkage platform so that the angle between the surface normal and the optical axis equals the representative incident angle, and the etching is completed after loading the corresponding parameter set. This invention effectively corrects spot distortion and energy attenuation through regional static wavefront pre-compensation and multi-parameter collaborative control, achieving high consistency in etching linewidth, depth, and morphology across the entire curved surface, significantly improving the manufacturing accuracy and reliability of the conformal circuit.

Description

Technical Field

[0001] This invention relates to the field of laser three-dimensional processing technology, and more specifically to the field of laser processing method and system technology for narrow-pitch discrete tombstone array circuits. Background Technology

[0002] With the rapid development of advanced electronic systems towards miniaturization, integration, and conformal design, the direct fabrication of high-performance conformal circuits on complex curved surfaces has become a key technological requirement in high-end applications such as aerospace conformal phased array antennas, 3D integrated packaging, flexible wearable electronics, and smart skins. Among these, narrow-pitch discrete tombston metallized arrays, as a typical curved circuit structure, have attracted much attention due to their excellent high-frequency characteristics and space utilization.

[0003] Currently, the mainstream processing method in this field is an etching process using ultrashort pulse lasers combined with galvanometer scanning. The basic process involves first covering the entire surface of the discrete tombstoning array sample with a thin metal film using methods such as physical vapor deposition. Then, a high-energy laser beam is used to selectively ablate and remove excess metal areas, thus preserving the desired circuit pattern. This technique offers significant advantages such as being non-contact, maskless, highly precise, and fast.

[0004] However, when this technology is applied to complex curved surfaces with large tilt angles (such as hemispherical domes, airfoil surfaces, etc.), the laser beam incident at a large angle onto the processing surface will cause a series of serious optical problems, resulting in a sharp decline in etching quality and consistency, specifically in the following three aspects: First, there are issues with the geometric distortion and aberrations of the laser spot: Traditional laser scanning systems often use f-θ lenses for flat-field focusing. When the laser beam is incident on a curved surface at a large angle, a significant projection effect occurs, while also introducing the inherent off-axis aberrations of the optical system. This causes the focused spot to no longer be an ideal circle, but rather stretched into an ellipse or even an irregular shape, while the energy distribution diverges. The direct consequences are severely uneven etching linewidth, jagged edges, and deteriorated sidewall steepness, making it difficult to meet the stringent requirements of narrow tombstoning circuits for pattern size and positional accuracy.

[0005] Second, the effective energy density drops sharply: According to Lambert's cosine law, the laser energy density received per unit area of ​​material when the laser is incident at an oblique angle is proportional to the cosine of the incident angle. Simultaneously, the area of ​​the laser spot increases due to distortion, further diluting the energy density. The combined effect of these two factors leads to a significant reduction in the actual energy density acting on the metal layer, easily resulting in problems such as insufficient etching depth, discontinuous etch lines, or even complete inability to remove the metal layer, severely damaging the electrical connectivity and signal integrity of the circuit pattern.

[0006] Third, the difficulty of conformal focus control increases: the inherent height undulations of the curved surface, coupled with the additional defocusing introduced by oblique incidence, make it difficult to maintain the laser focus continuously and accurately on the workpiece surface. Traditional static focusing methods cannot adapt to such rapid spatial changes; while relying solely on dynamic focusing modules can track the surface morphology to some extent, it cannot correct wavefront distortion and spot asymmetry caused by beam tilt.

[0007] To address the aforementioned issues, existing technologies have attempted several methods, but all have significant limitations. For example, patents with publication numbers CN101786200A and CN118760058A employ segmented planning and near-planar processing of small areas, but the consistency between areas is poor, resulting in noticeable distortion of the light spot at large incident angles. Patents with publication numbers CN121423846A and CN117020398B attempt to optimize the scanning path and angle, but cannot fundamentally correct optical aberrations. Patent CN111055010B uses a dedicated aspherical lens to improve focusing in specific applications, but the system is complex, costly, and lacks versatility and flexibility, making it difficult to adapt to changes in arbitrary curved surfaces.

[0008] Spatial light modulators (SLMs), as advanced beam shaping devices, theoretically possess wavefront modulation capabilities that can be used to correct aberrations. However, effectively integrating them into high-speed laser scanning processing systems remains an unsolved engineering challenge. The main bottleneck lies in the order-of-magnitude difference between the refresh rate of SLMs (typically in the millisecond range) and the scanning jump speed of high-speed galvanometers (in the microsecond range), making real-time, synchronous dynamic wavefront following impossible. This limits their direct application in dynamic processing.

[0009] Therefore, there is an urgent need to develop an innovative laser processing method that can effectively overcome the spot distortion and insufficient energy loss when processing curved surfaces at large angles of oblique incidence, thereby achieving high consistency and high precision manufacturing of narrow tombstone metallized circuits across the entire curved surface range. Summary of the Invention

[0010] The purpose of this invention is to address the technical problem that existing pulsed lasers, when incident at large angles during the etching of narrow-pitch tombstone array structures, produce significant spot distortion and energy dispersion, resulting in inconsistent linewidth, positional accuracy, and edge steepness that fail to meet the requirements of high-density three-dimensional circuit manufacturing. This invention provides a laser processing method and system for narrow-pitch discrete tombstone array circuits. It achieves precise correction of the spot morphology and energy distribution across the entire curved surface, ultimately efficiently obtaining curved surface circuits with consistent etching depth, linewidth accuracy, and morphological quality on complex narrow-pitch discrete tombstone array substrates, significantly improving the reliability and process consistency of three-dimensional curved surface micro-machining.

[0011] To achieve the above objectives, the present invention specifically adopts the following technical solution: One aspect of the present invention provides a laser processing method for a narrow-pitch discrete tombston array circuit, comprising the following steps: Step S1, Metallization pretreatment of discrete tombstoning array samples: Deposit a continuous metal thin film layer on the surface of the discrete tombstoning array samples; Step S2, 3D model partitioning and deconstruction: Obtain the 3D model of the discrete tombstone array sample, and discretize the discrete tombstone array sample into multiple processing sub-regions according to the preset incident angle tolerance threshold, and assign a representative incident angle to each processing sub-region, thereby discretizing the continuously changing complex surface into several processing units with independent characteristics. Step S3: Constructing the incident angle-wavefront compensation database: On a laser processing system integrated with a spatial light modulator, construct an incident angle-wavefront compensation database to generate a set of collaborative processing parameters corresponding to different representative incident angles. The set of collaborative processing parameters includes a spatial light modulator compensation phase map, energy compensation parameters, scanning parameters, and dynamic focusing parameters. Step S4, Zoned Collaborative Etching: The discrete tombstoning array sample with deposited metal thin film is clamped and positioned, and each processing sub-region is etched sequentially according to the planned order. During the etching of each processing sub-region, the pose of the discrete tombstoning array sample is adjusted through a multi-axis linkage platform so that the angle between the surface normal of the current processing sub-region and the laser incident direction is equal to the representative incident angle of the processing sub-region; a collaborative processing parameter set corresponding to the representative incident angle is loaded; under the control of the parameter set, the laser scanning etching of all circuit patterns in the current processing sub-region is completed. Step S5: Repeat step S4 until all processing sub-regions are completed, thereby obtaining a narrow-pitch discrete tombstoning metallized array circuit with consistent etching accuracy and morphological quality on the discrete tombstoning array sample.

[0012] In one embodiment, in step S1, a continuous metal thin film layer is formed on the surface of the discrete tombston array sample by one or more combinations of magnetron sputtering, ion beam sputtering, vapor deposition, atomic layer deposition or electroplating processes.

[0013] In one embodiment, in step S2, the tolerance range of the incident angle threshold is set to 1°~20°; representing that the incident angle is the arithmetic mean or weighted average of all incident angles in the corresponding processing sub-region.

[0014] In one embodiment, the energy compensation parameter in step S3 is calculated based on the cosine attenuation effect of the laser incident angle and the actual spot area change after modulation by the spatial light modulator, and the energy density is uniformized by adjusting one or more combinations of laser power, pulse energy or scanning speed.

[0015] In one implementation, the spatial light modulator compensation phase map in step S3 is obtained by measuring the aberrations of the focal plane at different tilted incident angles using a wavefront sensor and calculating its conjugate phase map, or by performing ray tracing and wavefront simulation calculations using optical simulation software.

[0016] In one implementation, during step S4, when switching between different sub-regions for processing, the pose adjustment of the multi-axis linkage platform, the phase map loading of the spatial light modulator, the parameter update of the dynamic focusing module, and the adjustment of the laser output or scanning parameters are synchronously coordinated and controlled by the system controller.

[0017] The second aspect of the present invention provides a laser processing system for a narrow-pitch discrete tombstone array circuit, used to implement the above-mentioned laser processing method for a narrow-pitch discrete tombstone array circuit, including a spatial light modulator, a laser, a beam expander group, a half glass slide, a diffraction filtering system, a dynamic focusing system, a mirror, a scanning galvanometer, an f-θ focusing lens, a discrete tombstone array sample, a multi-axis linkage platform, and a system controller. The laser, beam expander assembly, half-glass slide, diffraction filter system, dynamic focusing system, mirror, scanning galvanometer, and f-θ focusing lens are arranged sequentially along the optical path; The dynamic focusing system is used to adjust the position of the laser focus along the optical axis. Scanning galvanometers are used to control the deflection of the laser beam in a two-dimensional plane; The f-θ focusing lens focuses the beam deflected by the scanning galvanometer onto the surface of the discrete tombstone array sample. The multi-axis linkage platform is used to fix and adjust the pose of discrete tombstone array samples, enabling multi-degree-of-freedom motion of the discrete tombstone array samples; The spatial light modulator, in conjunction with the beam splitter prism, is used to receive the light beam and apply wavefront phase modulation to achieve compensating modulation of the elliptical light spot generated by the light beam at different incident angles. The system controller is electrically connected to the laser, spatial light modulator, diffraction filter system, dynamic focusing system, scanning galvanometer, and multi-axis linkage platform. The system controller is configured to perform three-dimensional model processing and processing area planning, compensation parameter set calculation and allocation, multi-axis linkage platform positioning, phase map loading of spatial light modulator, dynamic focusing control, and synchronous operation of laser parameter modulation and galvanometer scanning.

[0018] In one embodiment, the spatial light modulator is a reflective liquid crystal phase modulator or a digital micromirror-based amplitude modulator.

[0019] In one embodiment, the beam expander assembly employs a Galilean beam expander system to adjust the laser beam waist diameter to match the incident aperture of the scanning device, while simultaneously reducing the beam divergence angle.

[0020] In one embodiment, the multi-axis linkage platform includes an X translation axis, a Y translation axis, a Z translation axis, an A rotation axis, a B rotation axis, or a C rotation axis to adapt to the spatial pose adjustment of complex curved surfaces; the multi-axis linkage platform works in conjunction with the scanning galvanometer to achieve continuous scanning etching of large-format or three-dimensional curved surfaces.

[0021] Specifically, a multi-axis linkage platform provides at least three-axis linear motion (X, Y, Z) and rotational capability around at least one rotational axis.

[0022] Working principle: The core working principle of this embodiment lies in the wavefront regional pre-compensation and multi-physics field coordinated control, which "transforms the dynamic into the static".

[0023] First, since point-to-point real-time control of the spatial light modulator is impossible in traditional high-speed galvanometer scanning processing, a surface partitioning strategy is creatively introduced. Based on the tolerable range of incident angle variation in laser processing (i.e., depth of focus and aberration tolerance), a complex surface is discretized into several "small plane" processing sub-regions with similar normals. In this way, within each processing sub-region, the incident angle of the laser can be considered as an approximately constant representative value, thus transforming the dynamic problem caused by continuous or discontinuous changes in the surface into a static problem within a finite number of processing sub-regions.

[0024] Based on this, for each static representative incident angle, optical simulation or experimental methods are used to accurately calculate the composite wavefront aberration generated at the focal plane after the laser beam passes through the entire optical system at that angle. Then, the conjugate phase diagram of this aberration is calculated and preloaded onto the spatial light modulator. When the laser beam passes through the spatial light modulator, its wavefront is pre-modulated with an inverse phase. This pre-distorted wavefront continues to propagate, and after passing through the subsequent optical system, its original system aberrations are exactly canceled out by the pre-modulation, ultimately forming an ideal, distortion-free focused spot on the focal plane. This is the core mechanism of "wavefront pre-compensation," the key being that the compensation is based on the processing sub-region rather than the scanning point, thus avoiding the rate bottleneck.

[0025] Simultaneously, this scheme also incorporates an energy compensation mechanism. Since the inherent cosine effect of the projected area still exists even after the spot shape is restored during oblique incidence, the required laser power or scanning speed is calculated in reverse based on the representative incident angle of each processing sub-region and the actual spot size after compensation, ensuring that the effective energy density acting on the material remains consistent with that under perpendicular incidence.

[0026] Finally, the system controller deeply coordinates the loading of the spatial light modulator phase map, the adjustment of laser power / scanning speed, the planning of dynamic focusing Z-axis trajectory, and the attitude adjustment of the multi-axis linkage platform to form a "machining parameter set" for each machining sub-region. During machining, the system sequentially switches machining sub-regions, loads the machining parameter set, and performs etching, ultimately achieving high-precision and high-consistency machining results across the entire curved surface.

[0027] This solution effectively corrects spot distortion and energy dispersion during laser etching of complex curved surfaces. Without the need for frequent adjustments to the laser head posture, it ensures the consistency of etching linewidth, positional accuracy, and edge steepness across the entire curved surface through regional static wavefront compensation and multi-parameter collaborative control. This significantly improves the reliability and process consistency of micro-machining of three-dimensional high-curvature surface samples.

[0028] The beneficial effects of this invention are as follows: 1. Completely solves the problem of beam distortion at large angles of incidence: This invention creatively combines a curved surface partitioning strategy with static wavefront pre-compensation technology. By pre-calculating and loading the corresponding compensation phase map for each sub-region with a specific incident angle, the beam stretching, deformation, and energy divergence caused by beam tilt and system aberrations are effectively corrected. Even under large incident angles of grazing incidence, a near-diffraction-limited circular focused beam can be recovered, fundamentally ensuring the consistency of etching linewidth and the steepness of the edges.

[0029] 2. Achieved uniform energy density across the entire curved surface: This invention not only restores the spot shape through wavefront compensation but also further couples an energy compensation mechanism. Based on the representative incident angle of each sub-region, combined with the cosine attenuation law and the compensated spot area, the laser power or scanning speed is precisely adjusted to ensure that regions with different tilt angles receive the same effective energy density, thereby obtaining a uniform etching depth and ensuring the electrical connectivity and reliability of the circuit.

[0030] 3. Overcoming the rate bottleneck of real-time wavefront modulation while achieving both high quality and high efficiency: This invention employs a "regional static compensation" strategy, rather than dynamically adjusting the spatial light modulator point-by-point during scanning. This decouples the refresh rate of the spatial light modulator from the high-speed scanning action of the galvanometer, perfectly avoiding the engineering challenge of rate mismatch between the two. It utilizes the powerful wavefront shaping capability of the spatial light modulator to ensure processing quality while maintaining the scanning efficiency of the high-speed galvanometer, achieving a balance between high quality and high efficiency.

[0031] 4. High process adaptability and versatility: This invention provides a complete solution from 3D model deconstruction and optical simulation compensation to multi-axis collaborative machining. This method is not dependent on specific surface shapes or substrate types; it can be applied to complex spherical, aspherical, free-form surfaces, and various composite material substrates through simple parameter configuration, providing universal technical support for high-end manufacturing fields such as conformal antennas and 3D circuits.

[0032] 5. Significantly improved final product performance and reliability: Due to the uniform etching topography, clear boundaries, and high linewidth accuracy, the integrity of narrow-pitch discrete tombston circuits in high-frequency signal transmission is effectively guaranteed, reducing signal reflection and loss. At the same time, consistent processing quality also improves the reliability of subsequent packaging and long-term service, meeting the stringent requirements for electronic system stability in harsh environments such as aerospace. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 This is a flowchart of a laser processing method for a narrow-pitch discrete tombstone array circuit; Figure 2 This is a schematic diagram of a laser processing system with a narrow-pitch discrete tombston array circuit. Figure 3 This is a schematic diagram of a discrete tombstoning array sample; Figure 4 yes Figure 3 Cross-sectional view of the monument; Figure 5 This is a schematic diagram of different layers in Example 1; Figure 6 The spatial light modulator phase mask diagrams in Example 1 represent incident angles of 10°, 30°, 50°, and 70°. Figure reference numerals: 1. Laser; 2. Beam expander group; 3. Half glass slide; 4. Spatial light modulator; 5. Beam splitter prism; 6. Diffraction filter system; 7. Dynamic focusing system; 8. Mirror; 9. Scanning galvanometer; 10. f-θ focusing lens; 11. Discrete tombstoning array sample; 12. Multi-axis linkage platform. Detailed Implementation

[0035] To make the technical problems, technical solutions, and technical effects of the present invention clearer, 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 some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0037] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0038] In the description of the embodiments of the present invention, it should be noted that the terms "inner", "outer", "upper", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0039] like Figure 1 As shown, one aspect of the present invention provides a laser processing method for a narrow-pitch discrete tombston array circuit, comprising the following steps: Step S1, Metallization pretreatment of discrete tombstoning array sample 11: Deposit a continuous metal thin film layer on the surface of discrete tombstoning array sample 11; Step S2, 3D model partitioning and deconstruction: Obtain the 3D model of the discrete tombstone array sample 11, and divide the discrete tombstone array sample 11 into multiple processing sub-regions according to the preset incident angle tolerance threshold, and assign a representative incident angle to each processing sub-region, thereby discretizing the complex surface into several processing units with independent features. Step S3: Constructing the incident angle-wavefront compensation database: On the laser processing system integrated with the spatial light modulator 4, construct the incident angle-wavefront compensation database and generate a set of collaborative processing parameters corresponding to different representative incident angles. The set of collaborative processing parameters includes the spatial light modulator 4 compensation phase diagram, energy compensation parameters, scanning parameters, and dynamic focusing parameters. Step S4, Zoned Co-etching: The discrete tombstone array sample 11 with deposited metal thin film is clamped and positioned, and each processing sub-region is etched sequentially according to the planned order. When etching each processing sub-region, the pose of the discrete tombstone array sample 11 is adjusted by the multi-axis linkage platform 12 so that the angle between the surface normal of the current processing sub-region and the laser incident direction is equal to the representative incident angle of the processing sub-region; the co-processing parameter set corresponding to the representative incident angle is loaded; under the control of the parameter set, the laser scanning etching of all circuit patterns in the current processing sub-region is completed. Step S5: Repeat step S4 until all processing sub-regions are completed, thereby obtaining a narrow-pitch discrete tombstone metallized array circuit with consistent etching accuracy and morphological quality on the discrete tombstone array sample 11.

[0040] In one embodiment, in step S1, a continuous metal thin film layer is formed on the surface of the discrete tombston array sample 11 by one or more combinations of magnetron sputtering, ion beam sputtering, vapor deposition, atomic layer deposition or electroplating processes.

[0041] In one embodiment, in step S2, the tolerance range of the incident angle threshold is set to 1°~20°; representing that the incident angle is the arithmetic mean or weighted average of all incident angles in the corresponding processing sub-region.

[0042] In one embodiment, the energy compensation parameter in step S3 is calculated based on the cosine attenuation effect of the laser incident angle and the actual spot area change after modulation by the spatial light modulator 4, and the energy density is uniformized by adjusting one or more combinations of laser power, pulse energy or scanning speed.

[0043] In one embodiment, the spatial light modulator 4 compensated phase map in step S3 is obtained by measuring the aberration of the focal plane at different tilted incident angles using a wavefront sensor and calculating its conjugate phase map, or by performing ray tracing and wavefront simulation calculations using optical simulation software.

[0044] In one embodiment, in step S4, when switching between different sub-regions for processing, the pose adjustment of the multi-axis linkage platform 12, the phase map loading of the spatial light modulator 4, the parameter update of the dynamic focusing module, and the adjustment of the laser output parameters are synchronously coordinated and controlled by the system controller.

[0045] The second aspect of the present invention provides a laser processing system for a narrow-pitch discrete tombstone array circuit, used to implement the above-mentioned laser processing method for a narrow-pitch discrete tombstone array circuit, including a spatial light modulator 4, a laser 1, a beam expander group 2, a half glass plate 3, a diffraction filtering system 6, a dynamic focusing system 7, a mirror 8, a scanning galvanometer 9, an f-θ focusing lens 10, a discrete tombstone array sample 11, a multi-axis linkage platform 12, and a system controller; Laser 1, beam expander group 2, half glass 3, diffraction filter system 6, dynamic focusing system 7, mirror 8, scanning galvanometer 9, and f-θ focusing lens 10 are arranged sequentially along the optical path; The dynamic focusing system 7 is used to adjust the position of the laser focus along the optical axis. The scanning galvanometer 9 is used to control the deflection of the laser beam in a two-dimensional plane; f-control focusing lens 10 focuses the beam deflected by scanning galvanometer 9 onto the surface of discrete tombstone array sample 11; The multi-axis linkage platform 12 is used to fix and adjust the pose of the discrete tombstone array sample 11, so as to realize the multi-degree-of-freedom motion of the discrete tombstone array sample 11. The spatial light modulator 4 works in conjunction with the beam splitter 5 to receive the light beam and apply wavefront phase modulation, thereby achieving compensation modulation of the elliptical light spot generated by the light beam at different incident angles. The system controller is electrically connected to the laser 1, the spatial light modulator 4, the diffraction filter system 6, the dynamic focusing system 7, the scanning galvanometer 9, and the multi-axis linkage platform 12, respectively. The system controller is configured to perform three-dimensional model processing and processing area planning, compensation parameter set calculation and allocation, coordinate the positioning of the multi-axis linkage platform 12, load the phase map of the spatial light modulator 4, perform dynamic focusing control, and synchronize the laser parameter modulation and galvanometer scanning.

[0046] In one embodiment, the spatial light modulator 4 is a reflective liquid crystal phase modulator or a digital micromirror-based amplitude modulator.

[0047] In one embodiment, laser 1 is a laser with a picosecond or femtosecond pulse width.

[0048] In one embodiment, the beam expander group 2 employs a Galilean beam expander system to adjust the laser beam waist diameter to match the incident aperture of the scanning device, while reducing the beam divergence angle.

[0049] In one embodiment, the multi-axis linkage platform 12 includes an X translation axis, a Y translation axis, a Z translation axis, an A rotation axis, a B rotation axis, and a C rotation axis to adapt to the spatial pose adjustment of complex curved surfaces; the multi-axis linkage platform 12 works in conjunction with the scanning galvanometer 9 to achieve continuous scanning etching of large-format or three-dimensional curved surfaces.

[0050] Specifically, the multi-axis linkage platform 12 provides at least three-axis linear motion (X, Y, Z) and rotational capability around at least one rotational axis.

[0051] Example 1 This embodiment illustrates the fabrication of a narrow-pitch discrete tombston metallized array circuit on a hemispherical radome made of epoxy resin composite material. The substrate material is epoxy resin composite material, with the bottom and side surfaces being vertical planes. The target circuit pattern is a discretely arranged microstrip metal line array, with an etching accuracy requirement of ±25μm. Figure 3 and Figure 4 As shown, the darkened black area in the cross-section represents the metal circuit pattern that needs to be preserved during etching, and the maximum incident angle of the structure is 80°. Figure 1 As shown, the specific method is as follows: S1. Pre-treatment of radome surface metallization: After cleaning and pretreatment of the radome surface, a thin metal film layer was deposited on its outer surface using magnetron sputtering. The sputtering target was copper, and the base vacuum was better than 5 × 10⁻⁶. -4 Pa sputtering power of 200 W and deposition time of 30 minutes yielded a copper film with a thickness of approximately 5 μm.

[0052] This embodiment uses, as follows: Figure 2 The processing system shown employs a 355nm picosecond ultraviolet pulsed laser and integrates a reflective liquid crystal SLM (1920×1080 pixels, 8μm pixel size) capable of compensating for and modulating elliptical beams at different incident angles. First, baseline process parameters were obtained by calibration on a planar copper film standard: under perpendicular incident conditions, the focused beam size is approximately 30μm; and with a laser power of 2.5 W, a repetition frequency of 100kHz, and a scanning speed of 1.5 m / s, the surface metal film can be removed in a single pass.

[0053] S2, 3D model partitioning and deconstruction: The 3D model of the monument array structure was divided into sub-regions, and an optimization algorithm was used to optimize the processing path. The entire monument structure was divided into 35 processing sub-regions. The representative incident angle of each sub-region was the arithmetic mean of the incident angles of all points within that region.

[0054] S3. Constructing the incident angle-wavefront compensation database: A ray tracing model of the laser processing system was established using ZEMAX optical simulation software to simulate the spot morphology and aberration distribution of the focal plane under different incident angles. In this embodiment, the incident angles were classified into four segments, A, B, C, and D, based on the sample size. These correspond to incident angle ranges of 0~20°, 20°~40°, 40°~60°, and 60°~80°, respectively, with representative incident angles of 10°, 30°, 50°, and 70°. Figure 6 As shown. For each sub-region's representative incident angle, the corresponding SLM-compensated phase diagram is calculated, as follows. Figure 5As shown in the figure, for each representative incident angle, the simulation shows that without compensation, the long axis of the laser spot is stretched into an ellipse of 30.45 μm, 34.62 μm, 46.67 μm, and 87.72 μm, respectively. After compensation, the laser spot recovers to a circle with a diameter of 30 μm. Simultaneously, the energy compensation coefficient is calculated based on the cosine attenuation effect. For example, at an incident angle of 30°, the energy attenuates to 88.3% of that at perpendicular incidence. Energy density compensation is achieved by increasing the laser power to 2.83 W. Dynamic focusing parameters are calculated based on the average radius of curvature of the sub-region to ensure that the laser spot remains well focused throughout the entire sub-region.

[0055] S4, Partition Collaborative Etching: A tombstone structure workpiece with deposited copper film is clamped on a five-axis motion platform. Following the planned sequence, a sub-region representing an incident angle of 10° is processed first. The workpiece pose is adjusted via the motion platform, the angle between the surface normal of the sub-region and the laser incident direction is adjusted, and this sub-region is placed at the center of the scanning field of view. The control system loads the corresponding collaborative processing parameter set for this sub-region, loads the SLM phase map, adjusts the laser power, and starts the processing flow. After completion, it automatically switches to the next sub-region, updates the parameter set, and repeats the above process until all sub-regions are processed.

[0056] S5. Processing result inspection: Finally, laser confocal microscopy was used for inspection. The results showed that the etching accuracy could reach ±15μm across the entire curved surface, the line spacing deviation was less than ±2μm, and there were no obvious seams or abrupt changes in line width at the boundaries of each sub-region, which met the design requirements.

Claims

1. A method of laser processing a narrow-pitch discrete monolith array circuit, characterized by, Includes the following steps: Step S1, Metallization pretreatment of discrete tombstoning array samples: Deposit a continuous metal thin film layer on the surface of the discrete tombstoning array samples; Step S2, 3D model partitioning and deconstruction: Obtain the 3D model of the discrete tombstone array sample, and divide the discrete tombstone array sample into multiple processing sub-regions according to the preset incident angle tolerance threshold. Assign a representative incident angle to each processing sub-region, thereby discretizing the complex curved surface that changes continuously or discontinuously into several processing units with independent characteristics. Step S3: Constructing the incident angle-wavefront compensation database: On a laser processing system integrated with a spatial light modulator, construct an incident angle-wavefront compensation database to generate a set of collaborative processing parameters corresponding to different representative incident angles. The set of collaborative processing parameters includes a spatial light modulator compensation phase map, energy compensation parameters, scanning parameters, and dynamic focusing parameters. Step S4, Zoned Collaborative Etching: The discrete tombstoning array sample with deposited metal thin film is clamped and positioned, and each processing sub-region is etched sequentially according to the planned order. During the etching of each processing sub-region, the pose of the discrete tombstoning array sample is adjusted through a multi-axis linkage platform so that the angle between the surface normal of the current processing sub-region and the laser incident direction is equal to the representative incident angle of the processing sub-region; a collaborative processing parameter set corresponding to the representative incident angle is loaded; under the control of the parameter set, the laser scanning etching of all circuit patterns in the current processing sub-region is completed. Step S5: Repeat step S4 until all processing sub-regions are completed, thereby obtaining a narrow-pitch discrete tombstoning metallized array circuit with consistent etching accuracy and morphological quality on the discrete tombstoning array sample.

2. The laser processing method for a narrow-pitch discrete tombstone array circuit according to claim 1, characterized in that, In step S1, a continuous metal thin film layer is formed on the surface of the discrete tombston array sample by one or more combinations of magnetron sputtering, ion beam sputtering, vapor deposition, atomic layer deposition or electroplating processes.

3. The laser processing method for a narrow-pitch discrete tombstone array circuit according to claim 1, characterized in that, In step S2, the tolerance range of the incident angle threshold is set to 1°~20°; representing that the incident angle is the arithmetic mean or weighted average of the incident angles of all points in the corresponding processing sub-region.

4. The laser processing method for a narrow-pitch discrete tombstone array circuit according to claim 1, characterized in that, The energy compensation parameters in step S3 are calculated based on the cosine attenuation effect of the laser incident angle and the actual spot area change after modulation by the spatial light modulator. The energy density is uniformized by adjusting one or more combinations of laser power, pulse energy, or scanning speed.

5. The laser processing method for a narrow-pitch discrete tombstone array circuit according to claim 1, characterized in that, The spatial light modulator compensation phase map in step S3 is obtained by measuring the aberrations of the focal plane at different tilted incident angles using a wavefront sensor and calculating their conjugate phase maps, or by performing ray tracing and wavefront simulation calculations using optical simulation software.

6. The laser processing method for a narrow-pitch discrete tombstone array circuit according to claim 1, characterized in that, In step S4, when switching between different sub-regions for processing, the pose adjustment of the multi-axis linkage platform, the phase map loading of the spatial light modulator, the parameter update of the dynamic focusing module, and the adjustment of laser output or scanning parameters are synchronously coordinated and controlled by the system controller.

7. A laser processing system for a narrow-pitch discrete tombstone array circuit, used to implement the laser processing method for a narrow-pitch discrete tombstone array circuit according to any one of claims 1 to 6, characterized in that, It includes a spatial light modulator, laser, beam expander assembly, half glass slide, diffraction filter system, dynamic focusing system, mirror, scanning galvanometer, f-θ focusing lens, discrete tombston array sample, multi-axis linkage platform, and system controller; The laser, beam expander assembly, half-glass slide, diffraction filter system, dynamic focusing system, mirror, scanning galvanometer, and f-θ focusing lens are arranged sequentially along the optical path; The dynamic focusing system is used to adjust the position of the laser focus along the optical axis; Scanning galvanometers are used to control the deflection of the laser beam in a two-dimensional plane; The f-θ focusing lens focuses the beam deflected by the scanning galvanometer onto the surface of the discrete tombstone array sample. The multi-axis linkage platform is used to fix and adjust the pose of discrete tombstone array samples, enabling multi-degree-of-freedom motion of the discrete tombstone array samples; The spatial light modulator, in conjunction with the beam splitter prism, is used to receive the light beam and apply wavefront phase modulation to achieve compensating modulation of the elliptical light spot produced by the light beam at different incident angles. The system controller is electrically connected to the laser, spatial light modulator, diffraction filter system, dynamic focusing system, scanning galvanometer, and multi-axis linkage platform. The system controller is configured to perform three-dimensional model processing and processing area planning, compensation parameter set calculation and allocation, multi-axis linkage platform positioning, phase map loading of spatial light modulator, dynamic focusing control, and synchronous operation of laser parameter modulation and galvanometer scanning.

8. The laser processing system for a narrow-pitch discrete tombstone array circuit according to claim 7, characterized in that, The spatial light modulator is either a reflective liquid crystal phase modulator or an amplitude modulator based on digital micromirrors.

9. A laser processing system for a narrow-pitch discrete tombstone array circuit according to claim 7, characterized in that, The beam expander assembly employs a Galilean beam expander system to adjust the laser beam waist diameter to match the entrance aperture of the scanning device, while simultaneously reducing the beam divergence angle.

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