Laser processing device and method suitable for TGV forming

Abstract

The invention relates to the technical field of laser processing, and discloses a laser processing device and method suitable for TGV forming, and the method comprises the steps: S1, a glass substrate is scanned in a confocal manner, a three-dimensional topological graph is obtained, and the three-dimensional topological graph comprises the three-dimensional coordinate, the thickness gradient and the positioning mark of the glass substrate; s2, based on the three-dimensional topological graph, a through hole body is formed through ultraviolet femtosecond laser etching, and intermediate infrared laser is synchronously and dynamically controlled to etch the side wall of the through hole body to generate a taper through hole with a preset taper angle; and S3, the incident angle of the ultraviolet femtosecond laser is adjusted on the side wall of the taper through hole according to the three-dimensional topological graph, and a plurality of heat dissipation grooves are etched through the ultraviolet femtosecond laser. According to the laser processing device and method suitable for TGV forming, signal integrity optimization and active heat dissipation functions are achieved in the same through hole, the application range of the TGV is widened, and the stability of the TGV during use is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of laser processing, and in particular to a laser processing device and a processing method suitable for TGV forming. Background Art

[0002] With the rapid development of technologies such as 5G / millimeter wave communications and three-dimensional heterogeneous integration, through-glass vias (TGVs) have become a key interconnect technology in high-frequency chip packaging, optoelectronic integration, and other fields due to their excellent high-frequency performance, high insulation, and thermal expansion matching capabilities. In scenarios such as automotive radar and millimeter-wave base stations, TGVs must simultaneously meet ultra-low signal loss, high heat dissipation efficiency, and micron-level alignment precision. Traditional through-silicon vias can no longer meet these requirements due to the high dielectric loss and thermal expansion mismatch of silicon-based materials.

[0003] Existing TGV laser processing mostly uses direct etching with ultraviolet / ultrafast lasers. Although it can form high aspect ratio through-holes, the single taper angle structure leads to severe high-frequency signal reflection. The fixed taper angle cannot adapt to the needs of multi-band signal transmission. The reflection loss in different frequency bands is high, and the thermal management function is missing. The traditional process only focuses on the conductivity of the through-hole, resulting in insufficient heat dissipation for high-power chips. The root cause is that the existing method cannot achieve signal integrity optimization and active heat dissipation function in the same through-hole through process control, which seriously restricts the application of TGV in high-frequency and high-power scenarios. Summary of the Invention

[0004] The purpose of the present invention is to provide a laser processing device and processing method suitable for TGV forming, so as to achieve signal integrity optimization and active heat dissipation function in the same through hole, thereby improving the application range of TGV and the stability during use.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: Design a laser processing method suitable for TGV forming, including: S1. Obtain a three-dimensional topological map of the glass substrate by confocal scanning, wherein the three-dimensional topological map includes three-dimensional coordinates, thickness gradient, and positioning marks of the glass substrate; S2. Based on the three-dimensional topological map, a through-hole body is formed by ultraviolet femtosecond laser etching, and a mid-infrared laser is simultaneously and dynamically controlled to etch the sidewalls of the through-hole body to form a tapered through-hole with a preset taper angle; S3. Adjusting the incident angle of the ultraviolet femtosecond laser on the sidewall of the tapered through hole according to the three-dimensional topological map, and etching a plurality of heat dissipation grooves by the ultraviolet femtosecond laser, wherein the density and depth of the heat dissipation grooves in different areas match the heat source distribution of the chip; S4. Based on the three-dimensional topology, sputtering a diffusion barrier layer in layers and gradient electroplating a conductive layer in the tapered through hole to generate a conductive metal layer, wherein the thickness distribution of the conductive metal layer matches the thermal expansion coefficient of the glass substrate; S5. Detect the signal transmission characteristics of the tapered through-hole with a conductive metal layer to obtain detection data. By inputting the monitoring data and the three-dimensional topology map into the defect data to train the machine learning model, the taper angle correction coefficient and the electroplating parameter optimization instructions are output and fed back to the control system.

[0006] Optionally, S1 specifically includes: S11, performing plasma cleaning on the glass substrate to remove surface contaminants, and using ultraviolet laser etching to form array-type positioning marks on the edge area of the glass substrate, wherein the positioning marks are cross alignment lines; S12. Perform three-dimensional topography detection on the glass substrate using a multispectral confocal scanning system, wherein a short-wavelength channel scans the surface roughness and the coordinates of the positioning mark, and a long-wavelength channel penetrates the glass substrate for tomographic imaging to obtain thickness gradient distribution and sub-surface defect location data, wherein the wavelength of the short-wavelength channel is 405 nm and the wavelength of the long-wavelength channel is 1550 nm; S13, performing three-dimensional spatial registration on the surface roughness data, thickness gradient data, and sub-surface defect data to generate a global topological model including the three-dimensional coordinates of the glass substrate, thickness gradient, defect distribution, and positioning marks; S14, matching the global topology model with the preset chip electrode layout coordinates, establishing a processing coordinate system based on the positioning mark, and marking the avoidance path of the defect risk area to form a three-dimensional topology map.

[0007] Optionally, S2 specifically includes: S21. Preset the pulse energy, repetition frequency, and focus position compensation parameters of the ultraviolet femtosecond laser according to the thickness gradient data of the three-dimensional topology map and the preset through-hole body depth, and simultaneously preset the power gradient and beam modulation mode of the mid-infrared laser; S22. Based on the defect avoidance path marked on the three-dimensional topology map, plan the spiral progressive etching path of the ultraviolet femtosecond laser, and calculate the synchronization parameters of the annular spot scanning path of the mid-infrared laser and the ultraviolet femtosecond laser; S23, starting the ultraviolet femtosecond laser to etch the through-hole body in a spiral progressive path, and synchronously starting the annular spot of the mid-infrared laser to scan along the axial direction of the through-hole, so as to form the initial tapered structure of the through-hole body through the coupling of the cold etching of the ultraviolet laser and the nonlinear thermal stress field of the mid-infrared laser; S24, real-time monitoring of the temperature field distribution on the side wall of the through-hole body, dynamically adjusting the power gradient of the mid-infrared laser and the size of the annular spot, so that the thermal stress field forms a gradient distribution in the axial direction, driving the hole wall material of the through-hole body to directionally melt and then solidify, generating a preset taper angle, and obtaining a tapered through-hole; S25, online detection of the taper angle and sidewall roughness of the tapered through hole by a confocal scanning system. If the deviation exceeds a preset threshold, feedback is sent to S21 to optimize the laser parameters.

[0008] Optionally, S23 specifically includes: S231, based on the preset spacing of the spiral progressive path and the target depth of the through-hole body, generate a layer-by-layer etching trajectory of the ultraviolet femtosecond laser, wherein the spacing of each spiral layer is dynamically compressed with the etching depth, and calculate the axial scanning speed of the annular spot and the pulse timing matching parameters of the ultraviolet femtosecond laser; S232, adjusting the Bessel beam mode of the ultraviolet femtosecond laser, and dynamically compensating the focus position along the Z axis according to the thickness gradient data of the three-dimensional topology map; S233, starting the ultraviolet femtosecond laser to etch the glass substrate layer by layer along a dynamic compression spiral path, synchronously triggering the mid-infrared laser to scan along the axial direction of the through-hole body with a ring-shaped spot at a speed of 50 μm / s, and its thermal stress field covers the ultraviolet etching area to form a temperature gradient, driving the directional melting of the hole wall material of the through-hole body; S234. The three-dimensional morphology data of the side wall of the through-hole body is collected in real time through the confocal scanning module. If local residues or taper angle deviations are detected, ultraviolet laser supplementary etching and mid-infrared laser local annealing are triggered to generate an initial taper structure.

[0009] Optionally, S24 specifically includes: S241, using an infrared thermal imager to collect temperature field distribution data at different axial depths of the through-hole body in real time, establish an axial temperature gradient model, and calculate a thermal stress distribution function corresponding to the taper angle of the through-hole body; S242. Based on the thermal stress distribution function, dynamically modulate the power gradient of the mid-infrared laser and the ratio of the inner and outer diameters of the annular spot to generate an axially decreasing annular energy density field; S243. Control the mid-infrared laser to scan along the axial direction of the through-hole body, so that the hole wall material melts and flows at 800°C, and directionally solidifies at 400-600°C to form a preset taper angle, thereby obtaining a tapered through-hole extending from the hole mouth to the hole bottom along the Z axis.

[0010] Optionally, S24 further includes, after S243: Ultraviolet femtosecond laser-induced breakdown spectroscopy is used to detect the composition changes in the melting zone in real time. If the glass phase is detected to be normal, a tapered through-hole is directly obtained. If glass phase separation is detected, mid-infrared laser secondary annealing is triggered to reconstruct the amorphous structure to obtain a tapered through-hole.

[0011] Optionally, S3 specifically includes: S31. Based on the preset chip heat source distribution data and the three-dimensional coordinates of the tapered through-hole, a heat flux density-groove parameter mapping model is established to calculate the target groove depth, spacing, and inclination angle at the axial position of each tapered through-hole. The high heat zone has a heat flux density greater than 100 W / mm², the low heat zone has a heat flux density less than 100 W / mm², and the groove spacing density in the high heat zone is greater than that in the low heat zone. S32, adjusting the incident direction of the ultraviolet femtosecond laser according to the inclination angle of the corresponding tapered through-hole, loading the tilted wavefront phase and vortex phase through the spatial light modulator to generate an asymmetric Bessel focus, and setting a spiral etching path of the ultraviolet femtosecond laser along the sidewall of the tapered through-hole; S33. Start ultraviolet femtosecond laser etching to obtain heat dissipation grooves, and synchronously trigger the high-speed galvanometer to scan along a spiral path, so that the depth and spacing of the heat dissipation grooves change dynamically with the heat flux density gradient.

[0012] Optionally, S4 specifically includes: S41, performing plasma activation treatment on the tapered through hole to remove residual contaminants on the hole wall and generate a hydroxylated surface; S42. Based on the thickness gradient data of the three-dimensional topology map, a titanium-titanium nitride composite barrier layer is layered on the inner wall of the tapered through hole using an alternating process of magnetron sputtering and atomic layer deposition; S43. According to the axial thermal expansion coefficient gradient of the tapered through hole, pulse reverse electroplating parameters are designed, and a copper layer is gradient-electroplated on the titanium-titanium nitride composite barrier layer to obtain a conductive metal layer.

[0013] A laser processing device suitable for TGV forming, using the laser processing method suitable for TGV forming as described above; Including multi-wavelength laser processing module, multi-spectral confocal scanning system and dynamic control module; The multi-wavelength laser processing module includes an ultraviolet femtosecond laser and a mid-infrared continuous laser, and is used to perform tapered through-hole processing on a glass substrate; The multi-spectral confocal scanning system is used to scan the glass substrate to form a three-dimensional topological map; The dynamic control module is used to monitor the axial temperature gradient of the through hole body during the processing and to monitor and detect the taper angle of the tapered through hole.

[0014] The present invention provides a laser processing device and method suitable for TGV forming, which has the following beneficial effects: The laser processing device and processing method suitable for TGV forming obtain a three-dimensional topological map of a glass substrate through confocal scanning, accurately calibrate the thickness gradient and three-dimensional coordinates of the substrate, and based on the three-dimensional topological map, use an ultraviolet femtosecond laser and a mid-infrared laser to work together. While the ultraviolet laser completes the etching of the through-hole body, the mid-infrared laser generates a preset taper angle structure on the hole wall that matches the chip electrode through dynamic thermal stress regulation. Subsequently, based on the thickness gradient data of the three-dimensional topological map, a diffusion barrier layer is layered and sputtered in the through-hole and a conductive metal layer is gradiently electroplated to achieve matching of the thermal expansion coefficient of the conductive metal layer and the substrate. Through the energy coupling of the ultraviolet femtosecond laser and the mid-infrared laser, the occurrence rate of microcracks is effectively reduced. The tapered through-hole with a preset taper angle that dynamically generates can reduce the reflection loss of high-frequency signals. The heat dissipation groove that matches the heat source distribution of the chip effectively reduces thermal resistance and improves heat dissipation efficiency. Therefore, while achieving high-precision TGV forming, the signal transmission performance and heat dissipation efficiency are synergistically optimized, effectively improving the stability and service life of the TGV. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flow chart of the laser processing applicable to TGV forming in the present invention. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative work shall fall within the scope of protection of the present invention.

[0017] See also Figure 1 The present invention provides a technical solution: a laser processing method suitable for TGV forming, comprising: S1. Scan the glass substrate confocally to obtain a three-dimensional topological map, which includes the three-dimensional coordinates, thickness gradient, and positioning marks of the glass substrate. The glass substrate is fully inspected using a multispectral confocal scanning system. The short-wavelength channel captures the surface morphology and UV laser etching positioning marks. The long-wavelength channel uses optical coherence tomography to obtain the substrate thickness gradient and sub-surface defect distribution. A three-dimensional topological map containing a coordinate grid, thickness heat map, and defect risk areas is generated to provide a spatial reference and obstacle avoidance path for subsequent processes. S2. Based on the three-dimensional topology, a through-hole body is formed by ultraviolet femtosecond laser etching, and a mid-infrared laser is synchronously and dynamically controlled to etch the side wall of the through-hole body to generate a tapered through-hole with a preset taper angle. Based on the thickness gradient data of the three-dimensional topology, the ultraviolet femtosecond laser etches the through-hole body in a spiral progressive path, and the mid-infrared laser is synchronously triggered to generate an annular thermal stress field. Through the axial temperature gradient, that is, 800°C at the hole mouth → 400°C at the hole bottom, the glass is melted and resolidified to form a continuously variable taper angle structure of 5°→1°. The angle between the inner wall of the through-hole body and the axis is the taper angle. For example, at 5°, the angle between the side wall and the axis is larger. For example, at 1°, the angle between the side wall and the axis is smaller. Combined with the confocal online detection and feedback system, high-precision processing with a microcrack incidence rate of ≤0.3% is achieved; S3. Adjust the incident angle of the ultraviolet femtosecond laser on the sidewall of the tapered through hole according to the three-dimensional topological map, and etch a plurality of heat dissipation grooves by the ultraviolet femtosecond laser. The density and depth of the heat dissipation grooves in different areas match the heat source distribution of the chip. According to the preset heat source distribution of the chip, adjust the incident angle of the ultraviolet femtosecond laser, and etch non-uniform heat dissipation grooves on the sidewall of the tapered through hole. Deep grooves are densely packed in the high-heat area, and shallow grooves are sparsely packed in the low-heat area. Specifically, the depth is 200 nm and the spacing is 3 μm. The heat dissipation efficiency of the glass substrate is improved by the heat dissipation grooves. S4. Based on the three-dimensional topological map, a diffusion barrier layer is layered and sputtered in the tapered through hole, and a conductive layer is gradient-plated to generate a conductive metal layer, wherein the thickness distribution of the conductive metal layer matches the thermal expansion coefficient of the glass substrate. A titanium-titanium nitride composite barrier layer is deposited on the inner wall of the tapered through hole using an alternating magnetron sputtering-atomic layer deposition process. Subsequently, pulse reverse electroplating parameters are designed based on the gradient of the thermal expansion coefficient, and a copper layer is gradient-plated on the barrier layer. Local annealing is performed by laser to improve the interface bonding strength between the electroplated copper layer and the glass substrate to obtain a conductive metal layer. S5. Detect the signal transmission characteristics of the tapered through-hole with a conductive metal layer to obtain detection data. By inputting the monitoring data and the three-dimensional topology map into the defect data to train the machine learning model, the taper angle correction coefficient and the electroplating parameter optimization instructions are output and fed back to the control system. Terahertz time-domain spectroscopy is used to detect the signal transmission loss of the metallized through-hole. Combined with the defect data of the three-dimensional topology map, the convolutional neural network model is trained to predict the root cause of the taper angle deviation and electroplating non-uniformity. The taper angle correction coefficient and the electroplating current gradient adjustment instruction are output and fed back to the laser processing control system to achieve process parameter optimization and improve the quality of subsequent products.

[0018] In this embodiment, as a preferred solution, S1 specifically includes: S11. Plasma cleaning is performed on the glass substrate to remove surface contaminants, and ultraviolet laser etching is performed on the edge region of the glass substrate to form an array of positioning marks, wherein the positioning marks are crosshairs. Argon-oxygen mixed gas plasma cleaning is performed to remove organic contaminants on the surface of the glass substrate, and ultraviolet femtosecond laser etching is performed on the edge region of the substrate to form array positioning marks, each of which is arranged in the form of a crosshair, providing a physical reference for subsequent multispectral scanning and establishment of a processing coordinate system. S12. Use a multi-spectral confocal scanning system to perform three-dimensional morphology detection on the glass substrate, wherein the short-wavelength channel scans the surface roughness and the coordinates of the positioning mark, and the long-wavelength channel penetrates the glass substrate for tomographic imaging to obtain thickness gradient distribution and sub-surface defect position data, wherein the wavelength of the short-wavelength channel is 405nm and the wavelength of the long-wavelength channel is 1550nm. A dual-channel confocal scanning system is used, and the short-wavelength channel scans the surface roughness and the coordinates of the positioning mark with lateral resolution; the long-wavelength channel penetrates the glass substrate based on optical coherence tomography technology, and obtains the thickness gradient distribution and three-dimensional coordinate data of sub-surface defects (i.e., bubbles and microcracks ≥1μm) by tomographic sectioning; S13. Performing three-dimensional spatial registration on the surface roughness data, thickness gradient data, and sub-surface defect data to generate a global topology model including the three-dimensional coordinates of the glass substrate, thickness gradient, defect distribution, and positioning marks. Performing spatial registration on the surface roughness data, thickness gradient data, and sub-surface defect data coordinates to generate a global topology model. The global topology model includes a three-dimensional coordinate grid, a thickness heat map, defect risk hotspots, and positioning marks. Scanning errors (such as optical distortion and thermal drift) are calibrated using a convolutional neural network. S14. Match the global topology model with the preset chip electrode layout coordinates, establish a processing coordinate system based on the positioning mark, and mark the avoidance path of the defect risk area to form a three-dimensional topology map. Import the global topology model into the chip electrode layout system, and achieve matching between the substrate coordinate system and the chip coordinate system through affine transformation. Use the positioning mark as the reference origin, mark the defect risk area and plan the spiral avoidance path, and finally output the three-dimensional topology map.

[0019] S2 specifically includes: S21. Preset the pulse energy, repetition frequency, and focus position compensation parameters of the ultraviolet femtosecond laser based on the thickness gradient data of the three-dimensional topology map and the preset through-hole body depth, and simultaneously preset the power gradient and beam modulation mode of the mid-infrared laser. Dynamically set the pulse energy, repetition frequency, and focus position compensation of the ultraviolet femtosecond laser based on the thickness gradient data of the three-dimensional topology map and the preset through-hole depth, and simultaneously configure the power gradient (for example, from 3W at the hole mouth to 0.5W at the hole bottom) and beam modulation mode of the mid-infrared laser. Verify the feasibility of the parameter combination through a finite element simulation model to ensure that the thermal stress field distribution matches the taper angle. S22. Based on the defect avoidance path marked on the three-dimensional topology map, the spiral progressive etching path of the ultraviolet femtosecond laser is planned, and the synchronization parameters of the annular spot scanning path of the mid-infrared laser and the ultraviolet femtosecond laser are calculated. The spiral path avoids the defect area and can effectively reduce the microcrack triggering rate. Based on the defect avoidance path marked on the three-dimensional topology map, the spiral progressive etching path of the ultraviolet femtosecond laser is planned, and the annular spot scanning path of the mid-infrared laser is synchronously calculated to avoid the expansion of microcracks caused by the superposition of thermal stress during the processing; S23. Start the ultraviolet femtosecond laser to etch the through-hole body in a spiral progressive path, and synchronously start the annular spot of the mid-infrared laser to scan along the axial direction of the through-hole. The initial tapered structure of the through-hole body is formed by coupling the cold etching of the ultraviolet laser with the nonlinear thermal stress field of the mid-infrared laser. The initial tapered structure is formed on the hole wall by coupling the cold etching of the ultraviolet laser with the nonlinear thermal stress field of the mid-infrared laser. The quasi-diffraction-free characteristic of the Bessel beam ensures the consistency of etching at the bottom of the deep hole. S24. Real-time monitoring of the temperature field distribution on the side wall of the through-hole body, dynamically adjusting the power gradient of the mid-infrared laser and the size of the annular spot, so that the thermal stress field forms a gradient distribution in the axial direction, driving the hole wall material of the through-hole body to directionally melt and then solidify, generating a preset taper angle, and obtaining a tapered through-hole. The taper angle is specifically a continuously variable taper angle structure, which can also be understood as a gradual pipe, where the taper angle gradually decreases from the hole mouth to the hole bottom, and the side wall is a smooth curve. The tapered through-hole is a funnel, with fixed upper and lower taper angles and a straight side wall. S25, online detection of the taper angle and sidewall roughness of the tapered through hole by a confocal scanning system. If the deviation exceeds a preset threshold, feedback is sent to S21 to optimize the laser parameters.

[0020] S23 specifically includes: S231. Based on the preset spacing of the spiral progressive path and the target depth of the through-hole body, generate a layer-by-layer etching trajectory of the ultraviolet femtosecond laser, wherein the spacing of each spiral layer is dynamically compressed with the etching depth, and the axial scanning speed of the annular spot and the pulse timing matching parameters of the ultraviolet femtosecond laser are calculated. The spacing of each spiral layer is dynamically adjusted through a path compression algorithm, that is, the spacing is compressed by 0.5 μm for every 20 μm of etching depth. The axial scanning speed of the mid-infrared laser annular spot and the ultraviolet femtosecond laser pulse timing are synchronously calculated to ensure that the ultraviolet etching and the mid-infrared thermal stress field are accurately superimposed in three-dimensional space to avoid the diffusion of the heat-affected zone; S232. Adjust the Bessel beam mode of the ultraviolet femtosecond laser and dynamically compensate the focus position along the Z axis according to the thickness gradient data of the three-dimensional topology map. Based on the thickness gradient data of the three-dimensional topology map (e.g., local thickening of 5 μm), dynamically adjust the Z axis focus position (compensation amount ±0.2 μm). Apply adaptive wavefront phase (Zernike polynomial correction) via the spatial light modulator to eliminate aberrations caused by substrate surface curvature (wavefront error ≤ λ / 10) and ensure the consistency of deep hole bottom etching. S233. Start the ultraviolet femtosecond laser to etch the glass substrate layer by layer along a dynamic compression spiral path. Synchronously trigger the mid-infrared laser to scan along the axial direction of the through-hole body with an annular spot at a speed of 50 μm / s. Its thermal stress field covers the ultraviolet etching area to form a temperature gradient, driving the directional melting of the hole wall material of the through-hole body. Start the ultraviolet femtosecond laser (pulse energy 3 μJ, single pulse removal volume 0.1 μm³) to etch layer by layer along the dynamic compression spiral path. Synchronously trigger the mid-infrared laser (annular spot outer diameter 12 μm / inner diameter 6 μm, power 2 W) to scan along the axial direction of the through-hole. The mid-infrared thermal stress field forms an axial temperature gradient on the hole wall (hole mouth 800°C → hole bottom 400°C), driving the molten glass (viscosity 10³ Pa·s) to migrate directionally to the low temperature zone, forming the initial tapered structure. S234. The three-dimensional morphology data of the side wall of the through-hole body is collected in real time by the confocal scanning module. If local residues or taper angle deviations are detected, ultraviolet laser supplementary etching and mid-infrared laser local annealing are triggered to generate an initial taper structure. The three-dimensional morphology data of the side wall of the through-hole is collected in real time by the confocal scanning module. If local residues (height ≥ 0.5μm) or taper angle deviations (>±0.5°) are detected, ultraviolet femtosecond laser supplementary etching (energy 1μJ, focused on the residual area) and mid-infrared laser local annealing (power 1.5W, duration 5ms) are triggered. The annealing process causes the molten glass to reflow and fill the microcracks (repair rate >90%), and finally the initial taper structure is generated.

[0021] S24 specifically includes: S241. Use an infrared thermal imager to collect real-time temperature field distribution data at different axial depths of the through-hole body, establish an axial temperature gradient model, and calculate the thermal stress distribution function corresponding to the taper angle of the through-hole body. Use a medium-wave infrared thermal imager to collect real-time axial temperature distribution data of the through-hole, establish an axial temperature gradient model (800°C at the hole mouth → 400°C at the hole bottom, gradient ≥ 50°C / mm). Based on the glass thermal expansion coefficient (e.g., CTE = 7ppm / °C) and the viscoelastic constitutive equation, calculate the thermal stress distribution function (maximum stress 200MPa at the hole mouth) and map it to the target taper angle (5° → 1°) to determine the required heat flux density at each depth (3W / mm² at the hole mouth → 0.5W / mm² at the hole bottom). S242. Based on the thermal stress distribution function, the power gradient of the mid-infrared laser and the ratio of the inner and outer diameters of the annular spot are dynamically modulated to generate an axially decreasing annular energy density field. Based on the thermal stress distribution function, a vortex phase (topological charge l = 2) and a Gaussian attenuation amplitude mask are applied via a spatial light modulator (SLM). The inner and outer diameters of the annular spot of the mid-infrared laser (1550nm) are dynamically compressed from 12μm / 6μm to 8μm / 4μm, and the power gradient is linearly reduced from 3W at the orifice to 0.5W at the bottom of the orifice. This modulation results in an axially decreasing annular energy density field (15J / mm² at the orifice to 2J / mm² at the bottom of the orifice), precisely matching the melting-solidification rate gradient required for taper angle molding. S243. Control a mid-infrared laser to scan axially along the main body of the through-hole, causing the hole wall material to melt and flow at 800°C and directionally solidify at 400-600°C, forming a preset taper angle to obtain a tapered through-hole extending along the Z-axis from the hole mouth to the bottom of the hole. Control a mid-infrared laser to scan axially along the tapered through-hole in a pulse mode with a pulse width of 10ms and a duty cycle of 30% (speed 20μm / s), forming a high-temperature melting zone (>800°C) and a low-temperature solidification zone (400-600°C) on the hole wall. Driven by surface tension and thermal stress, the molten glass (viscosity 10³Pa·s) directionally migrates from the high-temperature zone to the low-temperature zone (flow rate 0.5μm / ms), and forms a continuously variable taper angle structure (5°→1°±0.3°) after solidification. By adjusting the scanning speed and temperature gradient, the taper angle linearity error and sidewall roughness are reduced to adapt to the needs of high-frequency signal transmission.

[0022] S24 also includes after S243: Ultraviolet femtosecond laser-induced breakdown spectroscopy is used to detect the composition changes in the melting zone in real time. If the glass phase is detected to be normal, a tapered through-hole is directly obtained. If glass phase separation is detected, mid-infrared laser secondary annealing is triggered to reconstruct the amorphous structure to obtain a tapered through-hole.

[0023] S3 specifically includes: S31. Based on the preset chip heat source distribution data and the three-dimensional coordinates of the tapered through hole, a heat flux density-groove parameter mapping model is established to calculate the target groove depth, spacing, and inclination angle at the axial position of each tapered through hole. The high heat zone has a heat flux density greater than 100W / mm², and the low heat zone has a heat flux density less than 100W / mm². The groove spacing density in the high heat zone is greater than that in the low heat zone. Based on the chip heat source distribution data (such as infrared thermal imaging) and the three-dimensional coordinates of the tapered through hole, a heat flux density-groove parameter quantitative relationship model is established through finite element thermal simulation. The high heat zone (heat flux density greater than 100W / mm²) is calculated as a densely packed deep groove (target depth 500nm, spacing 1μm), and the low heat zone (≤100W / mm²) is set as a sparsely packed shallow groove (depth 200nm, spacing 3μm). The groove inclination angle (0°-30°) is dynamically matched according to the curvature of the through hole sidewall (radius ≥50μm); S32. Adjust the incident direction of the ultraviolet femtosecond laser according to the inclination angle of the corresponding tapered through-hole, load the inclined wavefront phase and vortex phase through the spatial light modulator to generate an asymmetric Bessel focus, and set the spiral etching path of the ultraviolet femtosecond laser along the side wall of the tapered through-hole. According to the target inclination angle of the groove (such as 25° in the high thermal zone and 10° in the low thermal zone), load the inclined wavefront phase and the vortex phase with a topological charge of l=3 through the spatial light modulator to convert the ultraviolet femtosecond laser into an asymmetric Bessel beam (long axis 8μm / short axis 3μm, focal depth 50μm). The Bessel beam is adapted to the curved surface of the tapered through-hole side wall (curvature radius ≥50μm) at an inclined incidence, and plan the spiral etching path (linear speed 50μm / s, path offset 2-5μm) to ensure the morphology consistency of the groove on the curved surface. S33. Start ultraviolet femtosecond laser etching to obtain heat dissipation grooves, and synchronously trigger the high-speed galvanometer to scan along a spiral path, so that the depth and spacing of the heat dissipation grooves change dynamically with the heat flux density gradient, so as to increase the heat dissipation contact area.

[0024] S4 specifically includes: S41. Plasma activation treatment was performed on the tapered vias to remove residual contaminants from the hole walls and create a hydroxylated surface. Activation was performed using an argon-oxygen mixture (Ar:O2 = 4:1) plasma (power 300W, pressure 50Pa). Ion bombardment (energy 50eV) removed residual contaminants (such as hydrocarbons or microparticles) from the hole walls and generated hydroxyl groups on the surface. Atomic force microscopy was used to verify the surface roughness after activation, and the hydroxyl density was increased to 8 / nm², providing a highly active bonding interface for subsequent metallization layers. S42. Based on the thickness gradient data from the three-dimensional topology map, a titanium-titanium nitride composite barrier layer was layered on the inner wall of the tapered through-hole using alternating magnetron sputtering and atomic layer deposition (ALD) processes. Based on the thickness gradient data from the three-dimensional topology map (local thickness difference ±0.2μm), a titanium-titanium nitride composite layer was layered on the hole wall using alternating magnetron sputtering (Ti target, power 500W, argon pressure 3mTorr) and atomic layer deposition (ALD, precursor TiCl4 / NH3, temperature 250°C). Magnetron sputtering rapidly deposited a 150nm titanium layer (at a rate of 10nm / s) to provide a high-bonding strength substrate. A titanium nitride layer (50nm, at a rate of 0.1nm / cycle) filled the micropores in the titanium layer (porosity reduced from 5% to <0.01%), preventing Na⁺ diffusion in the glass and improving barrier efficiency. S43. According to the axial thermal expansion coefficient gradient of the tapered through hole, pulse reverse electroplating parameters are designed, and a copper layer is gradient electroplated on the titanium-titanium nitride composite barrier layer to obtain a conductive metal layer. According to the axial thermal expansion coefficient gradient of the tapered through hole, pulse reverse electroplating parameters are designed, with a current density of 1.2A / dm² at the hole mouth (forward pulse 10ms / reverse pulse 5ms) and 0.8A / dm² at the hole bottom (forward 8ms / reverse 4ms). A copper layer is gradient deposited on the barrier layer by supercritical carbon dioxide assisted electroplating (pressure 7.4MPa, temperature 31°C).

[0025] A laser processing device suitable for TGV forming, using the laser processing method suitable for TGV forming as described above; Including multi-wavelength laser processing module, multi-spectral confocal scanning system and dynamic control module; The multi-wavelength laser processing module includes an ultraviolet femtosecond laser and a mid-infrared continuous laser, and is used to perform tapered through-hole processing on a glass substrate; The multi-spectral confocal scanning system is used to scan the glass substrate to form a three-dimensional topological map; The dynamic control module is used to monitor the axial temperature gradient of the through hole body during the processing and to monitor and detect the taper angle of the tapered through hole.

[0026] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A laser processing method suitable for TGV forming, characterized in that: include: S1. Obtain a three-dimensional topological map of the glass substrate by confocal scanning, wherein the three-dimensional topological map includes three-dimensional coordinates, thickness gradient, and positioning marks of the glass substrate; S2. Based on the three-dimensional topological map, a through-hole body is formed by ultraviolet femtosecond laser etching, and a mid-infrared laser is simultaneously and dynamically controlled to etch the sidewalls of the through-hole body to form a tapered through-hole with a preset taper angle; S3. Adjusting the incident angle of the ultraviolet femtosecond laser on the sidewall of the tapered through hole according to the three-dimensional topological map, and etching a plurality of heat dissipation grooves by the ultraviolet femtosecond laser, wherein the density and depth of the heat dissipation grooves in different areas match the heat source distribution of the chip; S4. Based on the three-dimensional topology, sputtering a diffusion barrier layer in layers and gradient electroplating a conductive layer in the tapered through hole to generate a conductive metal layer, wherein the thickness distribution of the conductive metal layer matches the thermal expansion coefficient of the glass substrate; S5. Detect the signal transmission characteristics of the tapered through-hole with a conductive metal layer to obtain detection data. By inputting the monitoring data and the three-dimensional topology map into the defect data to train the machine learning model, the taper angle correction coefficient and the electroplating parameter optimization instructions are output and fed back to the control system.

2. The laser processing method for TGV forming according to claim 1, characterized in that: S1 specifically includes: S11, performing plasma cleaning on the glass substrate to remove surface contaminants, and using ultraviolet laser etching to form array-type positioning marks on the edge area of the glass substrate, wherein the positioning marks are cross alignment lines; S12. Perform three-dimensional topography detection on the glass substrate using a multispectral confocal scanning system, wherein a short-wavelength channel scans the surface roughness and the coordinates of the positioning mark, and a long-wavelength channel penetrates the glass substrate for tomographic imaging to obtain thickness gradient distribution and sub-surface defect location data, wherein the wavelength of the short-wavelength channel is 405 nm and the wavelength of the long-wavelength channel is 1550 nm; S13, performing three-dimensional spatial registration on the surface roughness data, thickness gradient data, and sub-surface defect data to generate a global topological model including the three-dimensional coordinates of the glass substrate, thickness gradient, defect distribution, and positioning marks; S14, matching the global topology model with the preset chip electrode layout coordinates, establishing a processing coordinate system based on the positioning mark, and marking the avoidance path of the defect risk area to form a three-dimensional topology map.

3. The laser processing method for TGV forming according to claim 1, characterized in that: S2 specifically includes: S21. Preset the pulse energy, repetition frequency, and focus position compensation parameters of the ultraviolet femtosecond laser according to the thickness gradient data of the three-dimensional topology map and the preset through-hole body depth, and simultaneously preset the power gradient and beam modulation mode of the mid-infrared laser; S22. Based on the defect avoidance path marked on the three-dimensional topology map, plan the spiral progressive etching path of the ultraviolet femtosecond laser, and calculate the synchronization parameters of the annular spot scanning path of the mid-infrared laser and the ultraviolet femtosecond laser; S23, starting the ultraviolet femtosecond laser to etch the through-hole body in a spiral progressive path, and synchronously starting the annular spot of the mid-infrared laser to scan along the axial direction of the through-hole, so as to form the initial tapered structure of the through-hole body through the coupling of the cold etching of the ultraviolet laser and the nonlinear thermal stress field of the mid-infrared laser; S24, real-time monitoring of the temperature field distribution on the side wall of the through-hole body, dynamically adjusting the power gradient of the mid-infrared laser and the size of the annular spot, so that the thermal stress field forms a gradient distribution in the axial direction, driving the hole wall material of the through-hole body to directionally melt and then solidify, generating a preset taper angle, and obtaining a tapered through-hole; S25, online detection of the taper angle and sidewall roughness of the tapered through hole by a confocal scanning system. If the deviation exceeds a preset threshold, feedback is sent to S21 to optimize the laser parameters.

4. The laser processing method for TGV forming according to claim 3, characterized in that: S23 specifically includes: S231, based on the preset spacing of the spiral progressive path and the target depth of the through-hole body, generate a layer-by-layer etching trajectory of the ultraviolet femtosecond laser, wherein the spacing of each spiral layer is dynamically compressed with the etching depth, and calculate the axial scanning speed of the annular spot and the pulse timing matching parameters of the ultraviolet femtosecond laser; S232, adjusting the Bessel beam mode of the ultraviolet femtosecond laser, and dynamically compensating the focus position along the Z axis according to the thickness gradient data of the three-dimensional topology map; S233, starting the ultraviolet femtosecond laser to etch the glass substrate layer by layer along a dynamic compression spiral path, synchronously triggering the mid-infrared laser to scan along the axial direction of the through-hole body with a ring-shaped spot at a speed of 50 μm / s, and its thermal stress field covers the ultraviolet etching area to form a temperature gradient, driving the directional melting of the hole wall material of the through-hole body; S234. The three-dimensional morphology data of the side wall of the through-hole body is collected in real time through the confocal scanning module. If local residues or taper angle deviations are detected, ultraviolet laser supplementary etching and mid-infrared laser local annealing are triggered to generate an initial taper structure.

5. The laser processing method for TGV forming according to claim 3, characterized in that: S24 specifically includes: S241, using an infrared thermal imager to collect temperature field distribution data at different axial depths of the through-hole body in real time, establish an axial temperature gradient model, and calculate a thermal stress distribution function corresponding to the taper angle of the through-hole body; S242. Based on the thermal stress distribution function, dynamically modulate the power gradient of the mid-infrared laser and the ratio of the inner and outer diameters of the annular spot to generate an axially decreasing annular energy density field; S243. Control the mid-infrared laser to scan along the axial direction of the through-hole body, so that the hole wall material melts and flows at 800°C, and directionally solidifies at 400-600°C to form a preset taper angle, thereby obtaining a tapered through-hole extending from the hole mouth to the hole bottom along the Z axis.

6. The laser processing method for TGV forming according to claim 5, characterized in that: S24 also includes after S243: Ultraviolet femtosecond laser-induced breakdown spectroscopy is used to detect the composition changes in the melting zone in real time. If the glass phase is detected to be normal, a tapered through-hole is directly obtained. If glass phase separation is detected, mid-infrared laser secondary annealing is triggered to reconstruct the amorphous structure to obtain a tapered through-hole.

7. The laser processing method for TGV forming according to claim 1, characterized in that: S3 specifically includes: S31. Based on the preset chip heat source distribution data and the three-dimensional coordinates of the tapered through-hole, a heat flux density-groove parameter mapping model is established to calculate the target groove depth, spacing, and inclination angle at the axial position of each tapered through-hole. The high heat zone has a heat flux density greater than 100 W / mm², the low heat zone has a heat flux density less than 100 W / mm², and the groove spacing density in the high heat zone is greater than that in the low heat zone. S32, adjusting the incident direction of the ultraviolet femtosecond laser according to the inclination angle of the corresponding tapered through-hole, loading the tilted wavefront phase and vortex phase through the spatial light modulator to generate an asymmetric Bessel focus, and setting a spiral etching path of the ultraviolet femtosecond laser along the sidewall of the tapered through-hole; S33. Start ultraviolet femtosecond laser etching to obtain heat dissipation grooves, and synchronously trigger the high-speed galvanometer to scan along a spiral path, so that the depth and spacing of the heat dissipation grooves change dynamically with the heat flux density gradient.

8. The laser processing method for TGV forming according to claim 1, characterized in that: S4 specifically includes: S41, performing plasma activation treatment on the tapered through hole to remove residual contaminants on the hole wall and generate a hydroxylated surface; S42. Based on the thickness gradient data of the three-dimensional topology map, a titanium-titanium nitride composite barrier layer is layered on the inner wall of the tapered through hole using an alternating process of magnetron sputtering and atomic layer deposition; S43. According to the axial thermal expansion coefficient gradient of the tapered through hole, pulse reverse electroplating parameters are designed, and a copper layer is gradient-electroplated on the titanium-titanium nitride composite barrier layer to obtain a conductive metal layer.

9. A laser processing device suitable for TGV forming, characterized by: Adopting the laser processing method suitable for TGV forming as described in any one of claims 1 to 8; Including multi-wavelength laser processing module, multi-spectral confocal scanning system and dynamic control module; The multi-wavelength laser processing module includes an ultraviolet femtosecond laser and a mid-infrared continuous laser, and is used to perform tapered through-hole processing on a glass substrate; The multi-spectral confocal scanning system is used to scan the glass substrate to form a three-dimensional topological map; The dynamic control module is used to monitor the axial temperature gradient of the through hole body during the processing and to monitor and detect the taper angle of the tapered through hole.

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