Optical system and optical processing apparatus

Abstract

The application provides an optical system and an optical processing device. The optical system comprises a light source module and a light path transmission module. The light source module is used for outputting a processing laser pulse, and the processing laser pulse comprises a first laser pulse and a second laser pulse. The light path transmission module comprises a first light path transmission assembly and a second light path transmission assembly. The first light path transmission assembly is used for receiving the first laser pulse, and the first light path transmission assembly comprises a first shaping assembly, which is used for performing wavefront shaping on the first laser pulse, so that a generated first non-diffracting beam pulse performs through-hole processing on a substrate to be processed. The second light path transmission assembly is used for receiving the second laser pulse, and the second light path transmission assembly comprises a second shaping assembly, which is used for adjusting the polarization state of the second laser pulse from linear polarization to circular polarization, so that the second laser pulse with the circular polarization state is focused on the inner wall of the through-hole, so as to change the refractive index of the material of the inner wall of the through-hole, and perform through-hole processing and form an optical waveguide on the inner wall of the through-hole.

Description

Technical Field

[0001] This application relates to the field of laser processing technology, and in particular, to an optical system and optical processing equipment. Background Technology

[0002] Artificial intelligence (AI) chips, especially large-scale graphics processing units (GPUs) and tensor processors (TPUs), are developing towards larger sizes, higher computing density, and more integrated functions. Glass substrates, as a next-generation packaging material, offer significant advantages in AI chip packaging.

[0003] Because of its inherent rigidity and stability, glass substrates are not easily deformed, and they can be used to fabricate vias with higher aspect ratios, smaller diameters, and denser spacing, solving the fundamental problem of insufficient interconnects in multi-chip integration. Furthermore, as a near-perfect insulator, glass significantly reduces signal crosstalk and distortion, thus improving computing power.

[0004] Furthermore, the fabrication of optical waveguides within vias means that optical signals can be transmitted vertically between chip stacks, thereby enabling inter-chip communication with extremely low power consumption and ultra-high bandwidth.

[0005] However, through-hole processing on glass substrates, a core process in glass substrate manufacturing, faces numerous technical bottlenecks. Related technologies utilize ultraviolet nanosecond lasers for through-hole processing, but the presence of a heat-affected zone leads to microcracks and excessive sidewall roughness. Wet etching processes result in severe lateral corrosion. Furthermore, fabricating optical waveguides on the inner walls of the through-holes requires additional photolithography steps, leading to high process complexity and soaring costs. Utility Model Content

[0006] In view of this, this application provides an optical system and optical processing equipment, which aims to solve the problems of complex and high cost of traditional through-hole processing and optical waveguide processing.

[0007] In a first aspect, one embodiment of this application provides an optical system including a light source module and an optical path transmission module. The light source module is used to output processing laser pulses, including a first laser pulse and a second laser pulse. The optical path transmission module is used to receive the processing laser and guide it to irradiate a substrate to be processed, performing through-hole processing on the substrate to form a through-hole and processing the inner wall of the through-hole to form an optical waveguide. The optical path transmission module includes a first optical path transmission component and a second optical path transmission component. The first optical path transmission component is used to receive the first laser pulse and includes a first shaping component for wavefront shaping of the first laser pulse, so that the generated first non-diffraction beam pulse performs through-hole processing on the substrate. The second optical path transmission component is used to receive the second laser pulse and includes a second shaping component for adjusting the polarization state of the second laser pulse from linear polarization to circular polarization, so that the circularly polarized second laser pulse is focused on the inner wall of the through-hole, absorbing the photon energy of the circularly polarized second laser pulse to change the refractive index of the material of the inner wall of the through-hole.

[0008] Secondly, one embodiment of this application provides an optical processing apparatus, including the aforementioned optical system and optical moving platform. The optical moving platform is used to move a substrate to be processed, so that the substrate to be processed is located at a first processing position of a first optical path transmission component, and the through-hole is located at a second processing position of a second optical path transmission component.

[0009] One embodiment of this application integrates two optical path transmission components used for respectively realizing through-hole processing and optical waveguide processing of the through-hole inner wall into a single optical system. This allows for the simultaneous realization of two processing steps on the same glass substrate without additional procedures, which not only reduces process complexity but also improves processing efficiency. Furthermore, the light source module used in this application employs first and second laser pulses with different output wavelengths. These different laser pulses are used to achieve different processing techniques, further reducing process steps and costs.

[0010] Furthermore, using a non-diffraction laser pulse to process through-holes in the substrate helps ensure that the energy of the first laser pulse is precisely focused on the glass substrate, thus facilitating the processing of through-holes with regular shapes and smooth sidewalls. Moreover, after the through-hole processing is completed, using circularly polarized light to process the waveguides on the inner walls of the through-holes helps ensure that the optical waveguides formed on the inner walls of the through-holes have the same refractive index change, the same etching depth, or the same modification effect, thereby ensuring the consistency of the optical waveguides formed on the inner walls of the through-holes. Attached Figure Description

[0011] It should be understood that the following figures only illustrate certain embodiments of this application and should not be construed as limiting the scope.

[0012] It should be understood that the same or similar reference numerals are used in the accompanying drawings to denote the same or similar elements.

[0013] It should be understood that the accompanying drawings are only schematic, and the dimensions and scales of the elements in the drawings are not necessarily precise.

[0014] Figure 1 This is a schematic diagram of the structure of an optical system provided in an embodiment of this application.

[0015] Figure 2 This is a schematic diagram of the structure of an optical system provided in an embodiment of this application.

[0016] Figure 3 This is a schematic diagram of the structure of a first optical path transmission component provided in an embodiment of this application.

[0017] Figure 4 This is a schematic diagram of the structure of a first optical path transmission component provided in an embodiment of this application.

[0018] Figure 5 This is a schematic diagram of the structure of a first optical path transmission component provided in an embodiment of this application.

[0019] Figure 6 This is a schematic diagram of the structure of a first optical path transmission component provided in an embodiment of this application.

[0020] Figure 7 This is a schematic diagram of the structure of a first optical path transmission component provided in an embodiment of this application.

[0021] Figure 8 This is a schematic diagram of the structure of a second optical path transmission component provided in an embodiment of this application.

[0022] Figure 9 This is a schematic diagram of the structure of a second optical path transmission component provided in an embodiment of this application.

[0023] Figure 10 This is a schematic diagram of the structure of an optical system provided in an embodiment of this application.

[0024] Figure 11 This is a schematic diagram of the structure of an optical processing device provided in an embodiment of this application.

[0025] Figure 12a This is a schematic diagram of the intensity distribution of radially polarized light generated by an optical system provided in an embodiment of this application.

[0026] Figure 12b This is a schematic diagram of the polarization direction of radially polarized light generated by an optical system provided in an embodiment of this application.

[0027] Figure 13 For use Figure 11A schematic diagram of a through hole processed by optical processing equipment.

[0028] Figure 14 for Figure 13 A cross-sectional view of the through hole in the image.

[0029] Figure 15 This is a flowchart of a processing method for optical processing equipment provided in an embodiment of this application.

[0030] Figure 16 This is a schematic diagram of the structure of an optical processing device provided in an embodiment of this application. Detailed Implementation

[0031] The embodiments of this application are described below with reference to the accompanying drawings. It should be understood that there are various ways to implement this application, and it should not be construed as being limited to the embodiments described herein. The embodiments described herein are only for a more thorough and clear understanding of this application.

[0032] As a new generation of packaging material, glass substrates were first proposed by manufacturers such as Intel to replace organic substrates and silicon-based through-hole processing technology. They have significant advantages in AI chip packaging, including: 1. Excellent electrical performance: dielectric constant <5.0@10GHz, dielectric loss (tanδ<0.002) is 2 to 3 orders of magnitude lower than silicon-based materials; 2. Excellent physical properties: thermal expansion coefficient (CTE 3.2ppm / ℃) matches the chip, surface roughness Ra<0.5μm, supporting ultra-high density interconnects (integrating trillions of transistors per package).

[0033] Currently, through-glass via (TGV) fabrication on glass substrates generally includes laser processing, dry etching (plasma etching), wet etching, and mechanical processing. Because mechanical processing involves ultrasonic or grinding wheel processing, the aperture of the TGV is relatively large, making it unsuitable for the micron-level high-density TGV fabrication required in electronic packaging.

[0034] Laser processing removes materials through photothermal or photochemical effects. However, commonly used ultraviolet nanosecond lasers result in a heat-affected zone (>10μm) during processing, leading to microcracks and excessive sidewall roughness (Ra>500nm).

[0035] Dry etching (plasma etching) requires a vacuum environment where reactive gases (such as CF4, SF6, etc.) are introduced, and plasma is generated under the action of an radio frequency power supply. The active ions in the plasma physically bombard and chemically react with the glass surface, generating volatile products that are then removed. However, dry etching equipment is very expensive, the process is complex, time-consuming, and requires photomasks.

[0036] Traditional wet etching utilizes a chemical solution (usually hydrofluoric acid HF or buffered oxide etchant BOE) to react with glass (SiO2), generating soluble fluorosilicates to remove the material. However, wet etching results in severe lateral corrosion and via taper >5°, failing to meet requirements for high aspect ratios (>10:1) and perpendicularity (tilt angle <2°).

[0037] In addition, traditional equipment requires a separate photolithography process (such as mask exposure + ion exchange) to simultaneously fabricate vias and optical waveguides on the same substrate. If a femtosecond laser is used, it only supports a single function (via fabrication or optical waveguide fabrication), and the refractive index control accuracy in waveguide fabrication is low (Δn fluctuation > ±15%), with transmission loss > 0.5 dB / cm.

[0038] As mentioned above, in order to overcome the aforementioned technical problems, refer to Figures 1 to 15 This application provides an optical system 100 for realizing through-hole processing and optical waveguide processing on the inner wall of the through-hole. The optical system 100 may include a light source module 10 and an optical path transmission module 20. The light source module 10 outputs processing laser pulses S0, which may include a first laser pulse S1 and a second laser pulse S2. The first laser pulse S1 and the second laser pulse S2 may be laser pulses of different wavelengths, used to achieve different functions. For example, the first laser pulse is used for through-hole processing, and the second laser pulse is used for waveguide processing on the inner wall of the through-hole. The light source module can be a laser that simultaneously generates the first laser pulse S1 and the second laser pulse S2. The output wavelength of the laser can be selected, set, or tuned according to different requirements. For example, it can be a fiber femtosecond laser or a second harmonic frequency-doubled femtosecond laser. Of course, the light source module 10 may also include two lasers outputting different wavelengths; no specific limitation is made here.

[0039] The optical path transmission module 20 receives the processing laser pulse S0 and guides it to irradiate the substrate G to be processed, performing through-hole processing on the substrate G to form through-hole O and processing the inner wall of the through-hole to form an optical waveguide. The optical path transmission module 20 includes a first optical path transmission component 21 and a second optical path transmission component 23. That is, different laser pulses pass through different optical path transmission components to perform different processing procedures.

[0040] Continue to refer to Figure 1The first optical path transmission component 21 is used for through-hole processing. It includes a first shaping component 211, which shapes the first laser pulse S1 by wavefront shaping, so that the generated first non-diffraction beam pulse S11 performs through-hole processing on the substrate G to be processed. It can be understood that the first laser pulse S1 is shaped by the first shaping component 211 in the first optical path transmission component 21, generating the first non-diffraction beam pulse S11, which irradiates the glass substrate to perform through-hole processing.

[0041] It is worth noting that a diffraction-free beam pulse (e.g., a Bessel beam) is a special type of optical field distribution. Its core characteristic is that it can maintain the same spot shape and prevent energy diffusion over a long distance. This type of beam can process through-holes or long waveguides across the entire thickness of a glass substrate in a single operation without repeatedly moving the focus in the depth direction, thus greatly improving processing efficiency and consistency. Because through-holes across the entire glass substrate can be processed in one operation, the sidewalls of the through-holes are more vertical and smoother, avoiding step-like defects that may occur with multi-layer scanning.

[0042] It should also be noted that if the first laser pulse S1 attempts to directly penetrate the glass for processing, not only will refraction occur, but aberrations will also appear, such as blurred focus, decreased peak energy density, and beam distortion, severely affecting the processing inside the glass. "Wavefront shaping" can correct these aberrations in advance to ensure that the diffraction-free beam pulse is not distorted, thereby ensuring that the energy of the first laser pulse can be precisely focused on the glass substrate to process through holes with regular shapes, accurate positions, and smooth sidewalls. There are many methods for wavefront shaping, such as spatial light modulators (SLMs), deformable mirrors, and conical lenses.

[0043] Continue to refer to Figures 1 to 3 The second optical path transmission component 23 processes the inner wall of the through-hole to form an optical waveguide. It may include a second shaping component 231, which adjusts the polarization state of the second laser pulse S2 from linear polarization to circular polarization. This causes the circularly polarized second laser pulse (i.e., the third laser pulse S3) to be focused onto the inner wall of the through-hole, absorbing the photon energy of the third laser pulse S3. This alters the refractive index of the material of the inner wall of the through-hole, forming an optical waveguide. It can be understood that the second laser pulse S2 output from the laser is transmitted in a linearly polarized manner. After passing through the second shaping component 231, the polarization state of the second laser pulse changes from linear polarization to circular polarization (i.e., the third laser pulse S3). Thus, the third laser pulse S3 continues to transmit in a circularly polarized manner to process the optical waveguide on the inner wall of the through-hole.

[0044] It should be noted that when machining the inner wall of a through-hole using linearly polarized laser pulses, the absorption efficiency of the laser pulse varies at different locations on the inner wall. This can lead to inhomogeneity in the structure of the inner wall and even prevent the formation of a waveguide structure. In contrast, when machining the inner wall of a through-hole using circularly polarized laser pulses, the absorption efficiency is uniform at any point on the inner wall. This ensures that the optical waveguide formed on the inner wall of the through-hole has the same refractive index change, the same etching depth, or the same modification effect, thus ensuring consistent transmission performance in all directions. There are many ways to implement waveguide machining using circularly polarized light, such as direct writing of three-dimensional optical waveguides inside glass. Among these, there are various methods for implementing the second shaping component used to adjust the polarization state, such as quarter-wave plates and electro-optic modulators.

[0045] It's also important to understand that the second optical transmission component can be fabricated on the inner wall of a glass substrate using laser direct writing. Laser direct writing involves precisely controlled three-dimensional scanning of the glass substrate surface or interior using a highly focused second excitation pulse. Through the interaction between the laser and the material (such as photopolymerization, ablation, and modification), the waveguide structure is directly fabricated. For example, by ablating the glass substrate at the focal point, the internal properties of the glass (such as refractive index and chemical activity) can be altered. This method eliminates the need for masks, reducing processing steps and allowing for flexible fabrication based on different structures. Furthermore, this method can achieve nanometer-level precision.

[0046] This application integrates two optical path transmission components used for respectively realizing through-hole processing and optical waveguide processing of the through-hole inner wall into a single optical system, enabling simultaneous processing of both on the same glass substrate without additional steps. This not only reduces process complexity but also improves processing efficiency. Furthermore, the light source module used in this application employs first and second laser pulses with different output wavelengths. These different laser pulses are used to achieve different processing techniques, further reducing process steps and costs.

[0047] Furthermore, using a non-diffraction laser pulse to process through-holes in the substrate helps ensure that the energy of the first laser pulse is precisely focused on the glass substrate, thus facilitating the processing of through-holes with regular shapes and smooth sidewalls. Moreover, after the through-hole processing is completed, using circularly polarized light to process the waveguides on the inner walls of the through-holes helps ensure that the optical waveguides formed on the inner walls of the through-holes have the same refractive index change, the same etching depth, or the same modification effect, thereby ensuring the consistency of the optical waveguides formed on the inner walls of the through-holes.

[0048] It is understandable that a non-diffractive beam pulse can be a Bessel beam. The central spot of a Bessel beam can remain undiverged for a long distance in the propagation direction (i.e., it has a long depth of focus) and also has self-reconstruction capability. In practical applications, there are many methods to generate Bessel beams, such as conical lenses, spatial light modulators, and digital micromirror devices.

[0049] In one example, the light source module 10 can be a femtosecond laser. The center wavelength of the first laser pulse S1 is 1030nm±5nm, the pulse width is 200fs±50fs, and the repetition frequency is adjustable, with an adjustment range of 1 to 1MHz. The center wavelength of the second laser pulse S2 is 515nm±3nm, and the pulse width is 200fs±50fs.

[0050] It should be noted that, because the photon energy (1.2 eV) of the first laser pulse (1030 nm) is lower than the glass bandgap (~8 eV), it bypasses the linear absorption rule at specific locations inside the transparent glass, causing extreme, non-equilibrium, and permanent changes to the internal network structure (such as densification, defect generation, and bond recombination), while the surrounding glass material remains almost unaffected. These permanent changes not only alter the density and refractive index of a portion of the glass but also create numerous defect energy states, providing a prerequisite for subsequent optical waveguide fabrication on the inner walls of glass vias. Although the photon energy (2.4 eV) of the second laser pulse (515 nm) is lower than the bandgap energy, it can match the new defect energy states created by the first laser pulse. This allows the second laser pulse to be guided to the region pre-processed by the first laser pulse, and fine processing is performed through efficient single-photon absorption or low-order nonlinear absorption. This enables the fabrication of waveguide structures with higher refractive indices within the three-dimensional glass body, without affecting the surrounding material (i.e., the aforementioned laser direct writing).

[0051] In one example, reference Figure 4 The first shaping component 211 may include a conical lens 215, which is used to convert the spatial distribution of the first laser pulse S1 into a first non-diffraction beam pulse S11. The conical lens 215 is a conical optical element used to refract incident parallel light into a light cone. The light cone interferes during propagation, forming a Bessel beam in the overlapping region (depth of focus). The apex angle of the conical lens can be 170° to 178°, and its material can be fused silica. Of course, the apex angle of the conical lens can also be flexibly designed as needed. For example, the apex angle of the conical lens can be 170°, 172°, 174°, 176°, 178°, etc.

[0052] refer to Figure 5The first shaping component 211 may further include a plano-convex lens 217, which is used to adjust the focal depth and spot diameter of the first non-diffractive beam pulse S11 so that the adjusted focal depth and spot diameter of the first non-diffractive beam pulse are consistent with the size of the through-hole. It can be understood that after the first laser pulse S1 passes through the conical lens 215 and the plano-convex lens 217 successively, it can generate a spot with a specific focal depth (i.e., a range of focal depths, which is related to the depth of the through-hole) and diameter to match the size of the through-hole.

[0053] In another example, the focal length of the plano-convex lens is f = 100 mm, which allows for the fabrication of through-holes with a diameter of 2 μm on glass substrates with a thickness of no more than 1 mm (e.g., 1 mm, 0.9 mm). Of course, the focal length of the plano-convex lens needs to be flexibly designed according to the thickness of the glass substrate and the diameter of the through-hole. That is, a plano-convex lens with a fixed focal length can be selected, and by changing to plano-convex lenses with different focal lengths, it can be adapted to fabricate through-holes on glass substrates of different thicknesses. Alternatively, an adjustable focal length plano-convex lens can be selected; no specific limitation is made here.

[0054] refer to Figure 2 The first optical path transmission component 21 may further include a third shaping component 213. The third shaping component 213 is used to adjust the polarization state of the first laser pulse S1 from linear polarization to radial polarization. After the radially polarized first laser pulse (i.e., the fourth laser pulse S4) passes through the first shaping component 211, it generates a third non-diffractive beam pulse S5. The single pulse energy of the third non-diffractive beam pulse S5 is greater than the single pulse energy of the first non-diffractive beam pulse S11. In other words, the first laser pulse S1 first passes through the third shaping component 213 to adjust its polarization state from linear polarization to radial polarization to obtain the fourth laser pulse S4 (i.e., the radially polarized first laser pulse). The fourth laser pulse S4 passes through the first shaping component 211 to generate the third non-diffractive beam pulse S5. Compared to the first laser pulse that was not adjusted to radial polarization, an enhanced non-diffraction beam pulse was obtained. The enhanced non-diffraction beam pulse is also conducive to further compressing the beam to the diffraction limit, and the energy is more concentrated. This makes the spot produced by the third non-diffraction beam pulse S5 after irradiating the glass substrate surface smaller and with higher energy, thereby greatly improving the resolution and thus facilitating further improvement of the processing quality of through-hole processing.

[0055] It's important to understand that radially polarized light is a type of cylindrically symmetric polarized light. Its polarization direction at any point in the beam is perpendicular to the radial direction and points towards the optical axis, and its electric field vector is radially distributed. (Reference) Figure 13 a and Figure 13b. The intensity distribution and inward radial polarization direction of the generated radially polarized light clearly show that the intensity is stronger inside the radially polarized light. An ideal diffraction-free beam pulse is diffraction-free, its field distribution is described by a zero-order Bessel function, it has a central bright spot and a series of concentric rings, and possesses perfect diffraction-free and self-healing properties, requiring infinite energy. In practice, diffraction-free beam pulses (e.g., the first diffraction-free beam pulse S1) are usually generated into an approximate Bessel beam through a conical lens, and its diffraction-free properties can be maintained within a finite distance. Radially polarized light, due to its unique polarization direction, enhances the generation of a Bessel beam when combined with a conical lens. In other words, since radially polarized light is inherently circularly symmetric, when it passes through a similarly circularly symmetric conical lens, the entire system maintains perfect symmetry, thus facilitating the generation of a higher-quality Bessel beam closer to the theoretical model, with more pronounced diffraction-free and self-healing properties. Of course, there are many ways to convert linearly polarized light into radially polarized light.

[0056] In one example, reference Figures 3 to 6 The third shaping component 213 may include a first quarter-wave plate 2131 and a vortex wave plate 2133. The first laser pulse S1 passes through the first quarter-wave plate 2131 and the vortex wave plate 2133 before passing through the first shaping component 211. It can be understood that after passing through the first quarter-wave plate 2131 and the vortex wave plate 2133, the first laser pulse S1 generates a fourth laser pulse S4 (i.e., a radially polarized first laser pulse). After passing through the conical lens 215, the fourth laser pulse S4 generates a third non-diffraction beam pulse S5 (i.e., an enhanced non-diffraction beam pulse). Thus, the enhanced non-diffraction beam pulse irradiates the glass substrate to perform through-hole processing. Alternatively, the fourth laser pulse S4 may also pass through the conical lens 215 and then through a plano-convex lens 217 (e.g., with the focal depth extended to >1 mm), adjusting the focal depth to suit the size of the through-hole.

[0057] refer to Figure 6 and Figure 7 The first optical path transmission component 211 may further include a zoom beam expander component 219, which is used to adjust the diameter of the first laser pulse S1, thereby adjusting the diameter of the spot of the first laser pulse S1. The first laser pulse S1 passes through the zoom beam expander component 219, the third shaping component 213, and the first shaping component 211 in sequence. It can be understood that the first laser pulse S1 first passes through the zoom beam expander component 219 to pre-adjust the diameter of the spot, and then passes through the third shaping component 213 and the first shaping component 211 to obtain an enhanced, diffraction-free beam pulse. Alternatively, the first laser pulse S1 may pass through the zoom beam expander component 219, and then sequentially pass through a first quarter-wave plate 2131, a vortex wave plate 2133, a conical lens 215, and a plano-convex lens 217 before irradiating the glass substrate.

[0058] refer to Figure 1 and Figure 8 The second shaping component 23 may include a spot shape control component 233, which is used to adjust the energy distribution of the spot of the circularly polarized second laser pulse (i.e., the third laser pulse S3) so that the ellipticity of the spot is greater than 0.98. It is understood that after the second laser pulse S2 passes through the second shaping component 231 (e.g., a quarter-wave plate), the resulting circularly polarized light is not ideally circular; its ellipticity is generally greater than or equal to 0.9. After the third laser pulse S3, with an ellipticity greater than or equal to 0.9, passes through the spot shape control component 233, the ellipticity of the spot of the third laser pulse S3 is greater than 0.98, and its energy distribution is more uniform, effectively improving the longitudinal stretching of the waveguide cross-section, thereby enhancing the consistency of the waveguide at different locations.

[0059] In one example, reference Figure 9 The second shaping component 231 may include a second quarter-wave plate 2311, and the spot shape control component 233 may include a cylindrical mirror 2331. The second quarter-wave plate 2311 is used to adjust the polarization state of the second laser pulse from linear polarization to circular polarization, so that the circularly polarized second laser pulse is focused on the inner wall of the through hole. In this way, after the second laser pulse S2 passes through the second quarter-wave plate 2311 and the cylindrical mirror 2331, the ellipticity of the spot of the sixth laser pulse S6 is greater than 0.98, and its polarization state is circularly polarized, so as to perform waveguide processing on the inner wall of the through hole.

[0060] To improve the accuracy of through-hole and waveguide machining, refer to Figure 10 The optical system 100 may further include a positioning module 30, which may include a paraxial positioning system 31 and a coaxial imaging system 32. The paraxial positioning system 31 is used to position the substrate G to be processed, and the coaxial imaging system 32 is used to position the second circularly polarized laser pulse focused on the inner wall of the via. It is understood that the paraxial positioning module may include a CCD camera (5μm resolution) and a coaxial illumination source. The CCD camera acquires the position information of the substrate to be processed to achieve positioning and focusing, ensuring processing accuracy. The coaxial imaging system 32 may be coaxial with the objective lens in the second optical path transmission assembly to ensure that the waveguide processing position is located on the inner wall of the via. The processing position of the substrate is located at the focal point of the objective lens, so that the waveguide structure can be processed by laser direct writing. The coaxial imaging system 32 is internally equipped with a 550nm bandpass filter to ensure that the coaxial imaging system 32 obtains a high signal-to-noise ratio and high contrast image, thereby reliably monitoring the via processing process.

[0061] refer to Figure 11 and Figure 16This application also provides an optical processing apparatus 300, which includes the aforementioned optical system 100 and an optical moving platform 200. The optical moving platform 200 is used to move the substrate G to be processed, so that the substrate G is located at a first processing position of the first optical path transmission component, and the through hole is located at a second processing position of the second optical path transmission component.

[0062] refer to Figure 16 The optical processing equipment 300 may further include a controller 210, which controls the light source module 10 to output a first laser pulse S1, so that the first laser pulse S1 generates a first non-diffraction beam pulse after passing through the first optical path transmission component 21, and performs through-hole processing on the substrate to be processed. The controller 210 is also used to control the light source module 10 to output a second laser pulse S2, so that the second laser pulse S2 generates a circularly polarized second laser pulse after passing through the second optical path transmission component 23, and is focused on the inner wall of the through hole to change the refractive index of the material of the inner wall of the through hole.

[0063] The following example illustrates through-hole machining using enhanced Bessel beams and waveguide machining of the inner wall of through-holes using laser direct writing. Figures 1 to 16 This paper introduces a specific embodiment of the optical processing equipment 300.

[0064] refer to Figure 11 The optical system 100 includes a dual-wavelength femtosecond laser 11 and two different optical path transmission components. The first optical path transmission component includes a power attenuation component 138 (for adjusting the power of the first laser pulse output), an eighth mirror 128, a zoom beam expander component 219, a first quarter-wave plate 2131, a vortex wave plate 2133, a ninth mirror 129, a first dichroic mirror 130, a conical lens 215, a plano-convex lens 217, a first objective lens 134, and a paraxial positioning system 31. The power attenuation component 138 includes a zero-order half-wave plate 135 and a first polarizing beam splitter prism 136. The addition of the mirrors adjusts the transmission direction of the first laser pulse, which helps to make the overall optical system structure more compact. Thus, the first laser pulse S1 passes successively through the rate attenuation component 138 (used to adjust the power of the first laser pulse output), the eighth reflecting mirror 128, the zoom beam expander component 219, the first quarter-wave plate 2131, the vortex wave plate 2133, the ninth reflecting mirror 129, the first dichroic mirror 130, the conical lens 215, and the plano-convex lens 217 before passing through the first objective lens 134 and illuminating the position to be processed. The position to be processed is located at the focal point of the first objective lens 134.

[0065] A 500μm thick glass substrate is fixed on a three-dimensional optical moving platform 200 (positioning accuracy ±0.1μm), and the paraxial positioning system 31 is activated to position the glass substrate. The paraxial positioning system can be a vision positioning system.

[0066] It should be noted that the dual-wavelength femtosecond laser 11 (e.g., a femtosecond fiber laser, a second-harmonic generation femtosecond laser) is used to output a first laser pulse S1 (center wavelength 1030nm±5nm) and a second laser pulse S2 (515nm±3nm), with a pulse width of 200fs±50fs. The power attenuation component 138 includes a zero-order half-wave plate 135 and a polarizing beam splitter prism 136, enabling continuous energy adjustment within a range of 0.01μJ to 50μJ. For example, the pulse energy can be set to 20μJ (adjusted to a modification threshold of 8μJ by the power attenuator). The zoom beam expander component 219 can achieve 1 to 4x continuous zoom to achieve an output beam diameter of 8mm. For example, the zoom beam expander component 219 can be a zoom beam expander lens, set to a 2× expansion magnification. The first quarter-wave plate 2131 and the vortex wave plate 2133 (with adjustable topological charge q = 1, 2, 3; for example, q = 1 can generate radially polarized light) work together to produce a ring beam with radial polarization. The cone lens 215 (made of fused silica) has an apex angle of 170° to 178° and works with the plano-convex lens 217 to adjust the focal depth and diameter of the Bessel beam in the power control module 139. The focal length of the plano-convex lens 217 can be selected from 50mm to 100mm to obtain a diffraction-free beam with an adjustable center lobe diameter of 0.5μm to 2μm, thus adapting to glass substrates with thicknesses of 100um to 2000um.

[0067] The second optical path transmission assembly includes a tenth reflector 121, an eleventh reflector 122, a power control module 139, a first angle stabilizer 123, a second quarter-wave plate 2311, a second angle stabilizer 124, a cylindrical mirror 2331 (shaping and compressing the length of the light spot along the processing direction), a second dichroic mirror 131, a second objective lens 133, and a coaxial imaging system 32. The power control module 139 includes a second half-wave plate 125, a second polarizing beam-splitting prism 126, and a beam splitter 127, used to split the output second laser pulse S2 into beams, for example, with an energy splitting ratio of 95:5. The optical system may also include a power detector (e.g., a photosensitive type), used to feed back the power of the portion of the second laser pulse S2 after passing through the beam splitter 127 to a PID controller, which uses a PID algorithm to control a stepper motor (step angle 0.01°) to adjust the angle of the second half-wave plate 125. The laser energy is controlled by splitting light with a fixed polarization direction using a half-wave plate 125 and a second polarizing beam splitter prism 126, thereby achieving a closed-loop response time of <10ms. Furthermore, a relatively stable output power can be maintained through a PID controller, for example, an average power of 0.3W ± 0.8%. Thus, the power-controlled second laser pulse passes through a second quarter-wave plate 2311 and a cylindrical mirror 2331 to obtain circularly polarized light with an ellipticity >0.98, and finally, after passing through a second objective lens, it illuminates the inner wall of the through-hole in the glass substrate being processed. For example, the numerical aperture NA of the second objective lens is 0.7, and the working distance is 2mm. The optical signal output from the coaxial imaging system 32 is coupled to the circularly polarized light of the second objective lens through a second dichroic mirror 131. The coaxial imaging system 32 can be a vision positioning system.

[0068] The focal position of the second objective lens, which moves the glass substrate with the completed through-hole processing via a three-dimensional optical moving platform, is adjusted. The coaxial imaging system 32 is then activated to position the through-hole, moving it to a position of 50 μm. The optical moving platform then moves the glass substrate according to a preset path, instructing waveguide parameters to be written into it, thereby forming a waveguide within the through-hole. The elliptical spot of the cylindrical mirror, after compression, induces a change in the refractive index within the glass substrate, with the refractive index change ranging from Δn = 0.001 to 0.0001, to form a single-mode waveguide (reference). Figure 14 and Figure 15 ).

[0069] refer to Figure 16 This application also provides a processing method applicable to the aforementioned optical processing equipment 300, the processing method specifically including the following steps:

[0070] Step S10: According to the instruction, move the position of the optical moving platform so that the substrate to be processed is located at the first processing position of the first optical path transmission component.

[0071] Specifically, the optical moving platform moves the substrate G (e.g., a glass substrate) to be processed so that the processing position is moved to the focal position of the first objective lens.

[0072] Step S20: Control the light source module to output a first laser pulse so that the first laser pulse generates a first non-diffraction beam pulse after passing through the first optical path transmission component, and perform through-hole processing on the substrate to be processed.

[0073] Specifically, the light source module 10 is activated to output a first laser pulse S1. The first laser pulse S1 is transmitted through the first optical path transmission module to irradiate the substrate to be processed, thereby forming a through hole O.

[0074] Step S30: Move the position of the optical moving platform so that the substrate to be processed is located at the second processing position of the second optical path transmission component.

[0075] Specifically, after the through hole O is processed, the light source module 10 stops outputting the first laser pulse S1 and moves the glass substrate based on the position of the through hole so that the inner wall to be processed in the through hole is located at the focal position of the second objective lens in the second transmission module.

[0076] Step S40: Control the light source module to output a second laser pulse so that the second laser pulse generates a circularly polarized second laser pulse after passing through the second optical path transmission component, and is focused on the inner wall of the through hole to change the refractive index of the material of the inner wall of the through hole.

[0077] Specifically, the light source module 10 is activated and outputs a second laser pulse S2. After passing through the second optical path transmission component, the second laser pulse S2 generates a circularly polarized second laser pulse that is focused on the inner wall to be processed in the through hole. The refractive index of the inner wall changes after being irradiated, so as to form a waveguide on the inner wall of the through hole.

[0078] It is understood that in this application, directional descriptions such as "upper," "lower," "inner," and "outer" are relative rather than absolute. These directional terms may be applicable when the optical system provided in this application is positioned according to the posture and location shown in the accompanying drawings.

[0079] It should be understood that although terms such as "first" or "second" may be used in this application to describe various elements (such as the first laser pulse and the second laser pulse), these elements are not defined by these terms, which are only used to distinguish one element from another.

[0080] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0081] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

[0082] The components and devices described in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the accompanying drawings. As those skilled in the art will recognize, these components and devices can be connected, arranged, and configured in any manner.

[0083] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An optical system, characterized in that, include: A light source module is used to output laser pulses for processing, the laser pulses for processing including a first laser pulse and a second laser pulse; The optical path transmission module is used to receive the processing laser and guide it to irradiate the substrate to be processed, and to perform through-hole processing on the substrate to form through-holes and to process the inner wall of the through-holes to form optical waveguides. The optical path transmission module includes a first optical path transmission component and a second optical path transmission component. The first optical path transmission component is used to receive the first laser pulse. The first optical path transmission component includes a first shaping component, which is used to perform wavefront shaping on the first laser pulse so that the resulting first non-diffraction beam pulse performs through-hole processing on the substrate to be processed. The second optical path transmission component is used to receive the second laser pulse. The second optical path transmission component includes a second shaping component, which is used to adjust the polarization state of the second laser pulse from linear polarization to circular polarization, so that the circularly polarized second laser pulse is focused on the inner wall of the through hole, and absorbs the photon energy of the circularly polarized second laser pulse to change the refractive index of the material of the inner wall of the through hole.

2. The optical system according to claim 1, characterized in that, The first optical path transmission component further includes a third shaping component, which is used to adjust the polarization state of the first laser pulse from linear polarization to radial polarization. After the first laser pulse in the radial polarization state passes through the first shaping component, it generates a third non-diffraction beam pulse. The single pulse energy of the third non-diffraction beam pulse is greater than that of the first non-diffraction beam pulse.

3. The optical system according to claim 2, characterized in that, The third shaping component includes a first quarter-wave plate and a vortex wave plate. The first laser pulse passes through the first quarter-wave plate and the vortex wave plate before passing through the first shaping component.

4. The optical system according to claim 1, characterized in that, The first shaping component includes a conical lens, which is used to convert the spatial distribution of the first laser pulse into the first diffraction-free beam pulse.

5. The optical system according to claim 4, characterized in that, The first shaping component further includes a plano-convex lens, which is used to adjust the focal depth and spot diameter of the first non-diffractive beam pulse so that the adjusted focal depth and spot diameter of the first non-diffractive beam pulse are consistent with the size of the through hole.

6. The optical system according to claim 2, characterized in that, The first optical path transmission component further includes a zoom beam expander component for adjusting the diameter of the first laser pulse to adjust the diameter of the spot of the first laser pulse. The first laser pulse passes through the zoom beam expander component, the third shaping component, and the first shaping component in sequence.

7. The optical system according to claim 1, characterized in that, The second shaping component further includes a spot shape control element, which is used to adjust the energy distribution of the spot of the circularly polarized second laser pulse so that the ellipticity of the spot is greater than 0.

98.

8. The optical system according to claim 7, characterized in that, The second shaping component includes a second quarter-wave plate, and the spot shape control component includes a cylindrical mirror. The second quarter-wave plate is used to adjust the polarization state of the second laser pulse from linear polarization to circular polarization, so that the circularly polarized second laser pulse is focused on the inner wall of the through hole.

9. The optical system according to claim 1, characterized in that, The optical system further includes a positioning module, which includes a paraxial positioning system and a coaxial imaging system. The paraxial positioning system is used to position the substrate to be processed, and the coaxial imaging system is used to focus the circularly polarized second laser pulse onto the inner wall of the through hole.

10. An optical processing device, characterized in that, Including the optical system and optical mobile platform as described in any one of claims 1 to 9, The optical moving platform is used to move the substrate to be processed so that the substrate to be processed is located at the first processing position of the first optical path transmission component for through-hole processing, and so that the through-hole is located at the second processing position of the second optical path transmission component for waveguide processing of the inner wall of the through-hole.

11. The optical processing equipment according to claim 10, characterized in that, The optical processing equipment also includes a controller. The controller is used to control the light source module to output a first laser pulse, so that the first laser pulse generates a first non-diffraction beam pulse after passing through the first optical path transmission component, and positions the substrate to be processed at the first processing position of the first optical path transmission component for through-hole processing. The controller is also used to control the light source module to output a second laser pulse and to position the substrate to be processed at the second processing position of the second optical path transmission component, so that the second laser pulse generates a circularly polarized second laser pulse after passing through the second optical path transmission component and is focused on the inner wall of the through hole to change the refractive index of the material of the inner wall of the through hole.

Images