Alkali-free ceramic glass for carbon dioxide laser tgv and method of making same

Abstract

The application discloses alkali-free ceramic glass for carbon dioxide laser TGV and a preparation method thereof, and belongs to the technical field of glass.The high-quality through hole is prepared on the alkali-free ceramic glass through the optimized alkali-free ceramic glass formula, innovative laser parameters and process steps, and requirements of vertical interconnection structures in the electronic packaging field are met.

Description

Technical Field

[0001] The present invention relates to the technical field, and in particular to an alkali-free ceramic glass for a carbon dioxide laser TGV and a preparation method thereof. Background Art

[0002] As electronic devices continue to develop towards miniaturization and high performance, three-dimensional integration technology has become the key to improving the performance of electronic systems. Vertical electrical interconnection between chips is achieved through silicon via (TSV) technology, which can effectively shorten the signal transmission distance, increase data transmission rate and reduce power consumption. However, traditional silicon-based TSV technology has some limitations in application. For example, the thermal conductivity of silicon is relatively low, which easily leads to heat accumulation problems in high-power devices. Glass materials have become an ideal material to replace silicon for vertical interconnection due to their good insulation properties, low thermal expansion coefficient and chemical stability. In particular, alkali-free ceramic glass, which does not contain alkali metal ions, can effectively avoid the degradation of device performance due to ion migration in high temperature and humid environments.

[0003] Through-glass via (TGV) technology is key to achieving glass-to-metal interconnections. Among commonly used laser drilling methods, CO2 lasers offer high energy density and excellent material penetration, making them suitable for creating through-holes in glass. However, traditional glass materials have limitations in terms of dielectric constant, thermal expansion coefficient, and mechanical strength. When using CO2 lasers for through-hole processing, cracks are prone to forming within TGV holes, severely impacting product reliability and performance, limiting their further application in high-end semiconductors.

[0004] Therefore, developing a new alkali-free ceramic glass formula that is suitable for carbon dioxide laser to efficiently and accurately prepare high-quality through holes on alkali-free ceramic glass, while significantly reducing internal cracks in TGV holes and ensuring that the performance of the glass is not affected, is an urgent problem to be solved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: to overcome the shortcomings of the existing technology and provide an alkali-free ceramic glass for carbon dioxide laser TGV and a preparation method thereof. Through an optimized alkali-free ceramic glass formula, innovative laser parameters and process steps, high-quality through holes are prepared on the alkali-free ceramic glass to meet the requirements of the vertical interconnection structure in the field of electronic packaging.

[0006] The technical solution of the present invention is:

[0007] On the one hand, the present invention provides an alkali-free ceramic glass for a carbon dioxide laser TGV, comprising the following components in mass percentage: SiO2 50-67%, Al2O3 10-17%, B2O3 7-13%, ZnO 1-4%, TiO2 0.5-2%, BaO 0.5-3%, SrO 0.5-3%, MgO 0.5-3%, CaO 0.5-3%, Cr2O3 0.1-1%, ZrO2 2-5%, P2O5 1-3%, Y2O3 0.5-2%, CeO2 + La2O3 + Sc2O3 + BN 2-5%, and the mass ratio of CeO2, La2O3, Sc2O3 and BN is (1-2): (2-3): (1-2): (2-4).

[0008] SiO2: As the primary network former in glass, Si-O bonds possess high bond energy, building a stable glass network structure and imparting excellent chemical stability, mechanical strength, and insulating properties. An appropriate amount of SiO2 ensures the integrity and continuity of the glass network. Too low a content loosens the glass network, reducing mechanical strength and chemical stability. Too high a content raises the glass's melting point, increasing melting difficulty and hindering glass preparation.

[0009] Al2O3: It can partially replace SiO2 in the glass network, adjusting its structure. An appropriate amount of Al2O3, acting as a network intermediate, can improve the chemical stability, mechanical strength, and thermal shock resistance of glass, enhance the connectivity of the glass network, and inhibit crystallization. At high temperatures, Al-O bonds effectively maintain the stability of the glass network, making the glass less susceptible to structural damage from thermal shock or external forces.

[0010] Fluxes and modifiers

[0011] B2O3: An effective fluxing agent, the appropriate amount can lower the melting point and viscosity of glass. During the glass melting process, it can reduce the melting temperature of the molten glass, reducing energy consumption while also improving its fluidity and facilitating uniform mixing and clarification. Furthermore, B2O3 improves the thermal and chemical stability of glass, making it more stable under varying conditions.

[0012] ZnO not only refines the microstructure of glass, making it more uniform and reducing stress concentration points, but also disperses the thermal stress generated by laser processing, preventing localized excessive stress and cracking. ZnO also improves the chemical stability and devitrification resistance of glass. An appropriate amount of ZnO significantly enhances glass performance, ensuring that the glass maintains excellent performance in various environments.

[0013] Thermal stress regulation and crack suppression components

[0014] ZrO2: With its high thermal conductivity, an appropriate amount of ZrO2 can quickly disperse the thermal stress generated during laser processing. When laser energy acts on the glass, ZrO2 quickly conducts heat away, preventing thermal stress concentration that can lead to cracks. Furthermore, ZrO2 absorbs energy during its phase transition in the glass, further alleviating thermal stress, improving the glass's thermal shock resistance, and enhancing the material's stability during laser processing.

[0015] P2O5: As a network modifier, an appropriate amount of P2O5 can adjust the glass network structure and increase its toughness. P2O5 disrupts the continuity of the glass network, forming a relatively loose structure that effectively absorbs and disperses stress. During laser processing, the toughened glass is more resistant to crack initiation and propagation, significantly improving TGV yield and reliability.

[0016] Y2O3: With its high melting point and high chemical stability, it forms tiny dispersed phases in glass that hinder crack propagation. When a propagating crack encounters a Y2O3 dispersed phase, the crack's direction of propagation changes, consuming more energy and inhibiting further crack growth. An appropriate amount of Y2O3 can effectively suppress cracks while also improving the optical properties of the glass to a certain extent, positively impacting the transmission and absorption characteristics of lasers in glass.

[0017] Unique components (CeO2, La2O3, Sc2O3, BN)

[0018] CeO2, La2O3, Sc2O3, and BN play a key role in improving the laser processing performance, structural stability, and thermal conductivity of glass. If their overall content is less than 2%, their synergistic effect is not fully realized, and the glass's ability to absorb laser light and disperse thermal stress cannot be significantly improved. This leads to problems such as cracks and a large heat-affected zone during laser drilling. When their overall content exceeds 5%, on the one hand, it will change the original structure and performance balance of the glass, potentially leading to a decrease in the chemical stability, mechanical strength and other properties of the glass. On the other hand, excessive addition will increase costs and may introduce impurities or phase separation, affecting the quality and uniformity of the glass.

[0019] CeO2: It has excellent photocatalytic properties and thermal stability. During the laser drilling process, it absorbs laser energy, generating electron-hole pairs. This promotes the repair of internal defects in the glass, reduces the occurrence of microcracks, and improves the glass's antioxidant properties. An appropriate amount of CeO2 can effectively exert its defect repair and antioxidant properties, without affecting the optical and electrical properties of the glass due to excessive levels. If its content is too low, its repair and antioxidant effects are insignificant; if its content is too high, it may cause problems such as discoloration and loss of charge balance in the glass.

[0020] La2O3: It can significantly increase the refractive index of glass, optimize the laser propagation path in the glass, and make the laser energy more concentrated on the drilling area, improving drilling efficiency. The appropriate amount of La2O3 can effectively optimize the laser propagation path. If the content is too low, the optimization effect on laser propagation is insufficient; if the content is too high, the refractive index will increase excessively, causing the laser propagation path to bend excessively, affecting the drilling effect.

[0021] Sc2O3: It refines the glass's grain size, enhances its structural stability, and allows it to better disperse stress when subjected to laser thermal shock. An appropriate amount of Sc2O3 can achieve excellent grain refinement and structural stability. If the content is too low, the grain refinement effect is insignificant. If the content is too high, the internal structure of the glass may become too dense, increasing internal stress and making it more susceptible to cracking.

[0022] BN: With its high thermal conductivity and excellent chemical stability, it can significantly improve the thermal conductivity of glass, effectively dissipating heat generated by laser processing and reducing thermal stress concentration. An appropriate amount of BN can fully utilize its high thermal conductivity. If the content is too low, the improvement in thermal conductivity efficiency is limited. If the content is too high, it may affect the compatibility of BN with other glass components, resulting in an uneven glass structure.

[0023] Other ingredients

[0024] TiO2: An appropriate amount of TiO2 can improve the optical properties and chemical stability of glass. It can absorb ultraviolet rays and improve the weather resistance of glass. At the same time, it affects the refractive index of glass to a certain extent, regulates the propagation characteristics of laser in glass, and helps to optimize the laser processing effect.

[0025] BaO, SrO, MgO, and CaO: These alkaline earth metal oxides primarily play a role in adjusting glass properties. They can partially replace network-forming ions, affecting the structure and properties of the glass. When present in appropriate amounts, they can accelerate clarification of the glass solution, lower its melting point, and improve its chemical stability and thermal expansion coefficient, making it more suitable for applications in electronic packaging.

[0026] Cr2O3: An appropriate amount of Cr2O3 can significantly increase the material's absorption rate of CO2 lasers. Under laser irradiation, Cr2O3 absorbs laser energy and converts it into heat, causing a local temperature increase, promoting the formation of through holes, and improving the efficiency and quality of laser drilling.

[0027] On the other hand, the present invention provides a method for preparing the above-mentioned alkali-free ceramic glass for carbon dioxide laser TGV, comprising the following steps:

[0028] S1 Raw material preparation: Mix all raw materials evenly to obtain glass batch; since BN has certain chemical activity, it is necessary to keep the environment dry during the weighing and mixing process to avoid reaction with moisture;

[0029] S2 melting and annealing: annealing after glass melting to eliminate internal stress of the glass and obtain alkali-free ceramic glass body;

[0030] S3 laser drilling: Use carbon dioxide laser to perform laser drilling on alkali-free ceramic glass blanks;

[0031] S4 through-hole post-processing: The glass after laser drilling is cleaned, and then metallic copper is deposited in the through-hole by chemical plating. The specific operations are as follows: First, the cleaned glass is placed in an aqueous solution composed of 2-5wt.% stannous chloride and 4-8wt.% acid solution and soaked for 10-15 minutes to allow a layer of tin ions to be adsorbed on the glass surface; then, the glass is taken out, rinsed with deionized water, and placed in an aqueous solution composed of 0.1-0.3wt.% silver nitrate and 2-4wt.% ammonia water and soaked for 8-12 minutes to reduce the adsorbed tin ions to metallic tin, thereby forming a layer of catalytically active metallic silver layer on the glass surface and the through-hole (silver mirror reaction); finally, the glass is placed in an electroless copper plating solution at 30-40°C and a temperature of 0.5-1A / dm 2 Chemical copper plating is performed for 20-30 minutes at a current density of 1000 nm to deposit a uniform and dense metal copper layer in the through-hole, forming a good conductive path and realizing the electrical connection between the glass and the external circuit, thus obtaining the alkali-free ceramic glass for carbon dioxide laser TGV.

[0032] Preferably, in step S2, the smelting temperature is 1500-1600°C and the smelting time is 2-4 hours.

[0033] Preferably, in step S2, the annealing temperature is 550-650° C., and the time is 2-4 hours.

[0034] Preferably, in step S3, the laser power of the carbon dioxide laser is 50-100 W, the pulse frequency is 20-50 kHz, the scanning speed is 10-30 mm / s, and the spot diameter is 0.02-0.05 mm.

[0035] Preferably, in step S3, before laser drilling, the alkali-free ceramic glass body is pretreated by placing it in a vacuum environment and performing surface treatment on it using a low-temperature plasma treatment device for 10-15 minutes to enhance the activity of the glass surface.

[0036] Preferably, in step S3, during the laser drilling process, protective gas is sprayed into the drilling area, which can cool the glass surface and reduce thermal stress concentration on the one hand, and blow away debris generated during the drilling process on the other hand to prevent debris accumulation from affecting the drilling quality.

[0037] Preferably, the protective gas is argon with a flow rate of 5-10 L / min.

[0038] Preferably, in step S4, during cleaning, first ultrasonic cleaning is performed with deionized water for 15-20 minutes to remove most debris on the hole wall, then soaking in acid solution for 5-10 minutes to further remove residual metal impurities and fine particles, and then rinsing with deionized water.

[0039] Preferably, in step S4, the chemical copper plating solution comprises 15-20 g / L copper sulfate, 30-40 g / L potassium sodium tartrate, 10-15 g / L sodium hydroxide and 10-15 vol.% formaldehyde.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The present invention adds unique components to the alkali-free ceramic glass formula, which synergistically promotes defect repair, optimizes the laser propagation path, enhances structural stability, and improves heat conduction efficiency, thereby greatly improving the laser drilling effect. At the same time, the innovative laser drilling process of the present invention effectively reduces the problems of thermal stress concentration and debris accumulation, significantly reduces the number of cracks inside the TGV hole, and improves the drilling quality. The optimized chemical plating process makes the deposited metal copper layer more uniform and dense by precisely controlling the parameters of the copper plating process, thereby improving the electrical connection performance between the glass and the external circuit. Overall, the alkali-free ceramic glass prepared by the present invention meets the strict requirements of high-end semiconductor manufacturing for TGV technology and has good application prospects. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0043] Example 1

[0044] The alkali-free ceramic glass for a carbon dioxide laser TGV of this embodiment includes the following components in percentage by mass: SiO2 59.5%, Al2O3 14%, B2O3 10%, ZnO 2%, TiO2 1%, BaO 1.5%, SrO 1%, MgO 1.5%, CaO 1.5%, Cr2O3 0.5%, ZrO2 2.9%, P2O 52%, Y2O3 0.5%, CeO2 0.3%, La2O3 0.6%, Sc2O3 0.3%, and BN 0.9%.

[0045] The method for preparing the alkali-free ceramic glass for the carbon dioxide laser TGV of this embodiment includes the following steps:

[0046] S1 Raw material preparation: Mix all raw materials evenly to obtain glass batch;

[0047] S2 Melting and Annealing: Place the glass batch material into a platinum-rhodium crucible and melt it at 1550°C for 3 hours while stirring to ensure that the glass liquid is uniform; cast the glass liquid into a preheated mold and anneal it at 600°C for 3 hours to obtain an alkali-free ceramic glass body;

[0048] S3 laser drilling: Before laser drilling, place the alkali-free ceramic glass blank in a vacuum of 10 -3 In an environment of Pa, low-temperature plasma treatment was performed for 10 minutes. When a carbon dioxide laser was used to laser-drill holes in the alkali-free ceramic glass blank, the laser power was 75W, the pulse frequency was 35kHz, the scanning speed was 20mm / s, the spot diameter was 0.04mm, and pulse modulation technology was used. During the laser drilling process, argon gas was sprayed into the drilling area at a flow rate of 8L / min.

[0049] S4 through-hole post-processing: first, ultrasonically clean the laser-drilled glass with deionized water for 15 minutes, then soak it in 5wt.% hydrochloric acid solution for 5 minutes, and then rinse it with deionized water; then, use the chemical plating method to deposit metallic copper in the through-hole. The specific operations are as follows: first, soak the cleaned glass in an aqueous solution composed of 3wt.% stannous chloride and 5wt.% acid solution for 10 minutes to allow a layer of tin ions to be adsorbed on the glass surface; then, take out the glass, rinse it with deionized water, and soak it in an aqueous solution composed of 0.2wt.% silver nitrate and 3wt.% ammonia water for 8 minutes to reduce the adsorbed tin ions to metallic tin, thereby forming a layer of catalytically active metallic silver layer on the glass surface and the through-hole; finally, place the glass in an chemical copper plating solution composed of 18g / L copper sulfate, 35g / L potassium sodium tartrate, 12g / L sodium hydroxide and 12vol.% formaldehyde at 30°C and 0.5A / dm 2Chemical copper plating is performed for 20 minutes at a current density of , to deposit a uniform and dense metal copper layer in the through-hole, forming a good conductive path and realizing the electrical connection between the glass and the external circuit, thus obtaining the alkali-free ceramic glass for carbon dioxide laser TGV.

[0050] Performance testing of the alkali-free ceramic glass for CO2 laser TGVs prepared in this example showed that the through-holes had uniform apertures, with an average diameter of 0.058 mm, smooth pore walls, and minimal cracks. High-power microscope observation revealed no more than one crack per square centimeter of through-hole area. The glass also exhibited excellent insulation properties, with a leakage current of less than 6 μA at 100 V. The thermal expansion coefficient was 5.2 × 10 -6 / ℃, meeting the application requirements in the field of electronic packaging.

[0051] Example 2

[0052] The alkali-free ceramic glass for a carbon dioxide laser TGV of this embodiment includes the following components in percentage by mass: SiO2 59%, Al2O3 13.6%, B2O3 10%, ZnO 2%, TiO2 1%, BaO 1.5%, SrO 1%, MgO 1.5%, CaO 1.5%, Cr2O3 0.5%, ZrO2 2.9%, P2O 52%, Y2O3 0.5%, CeO2 0.5%, La2O3 1%, Sc2O3 0.5%, and BN 1%.

[0053] The method for preparing the alkali-free ceramic glass for the carbon dioxide laser TGV of this embodiment includes the following steps:

[0054] S1 Raw material preparation: Mix all raw materials evenly to obtain glass batch;

[0055] S2 Melting and Annealing: Place the glass batch material into a platinum-rhodium crucible and melt it at 1580°C for 3.5 hours while stirring to ensure that the glass liquid is uniform; cast the glass liquid into a preheated mold and anneal it at 620°C for 3.5 hours to obtain an alkali-free ceramic glass body;

[0056] S3 laser drilling: Before laser drilling, place the alkali-free ceramic glass blank in a vacuum of 10 -2 In an environment of Pa, low-temperature plasma treatment was performed for 12 minutes. When a carbon dioxide laser was used to laser-drill holes in the alkali-free ceramic glass blank, the laser power was 80W, the pulse frequency was 40kHz, the scanning speed was 25mm / s, the spot diameter was 0.035mm, and pulse modulation technology was used. During the laser drilling process, argon gas was sprayed into the drilling area at a flow rate of 9L / min.

[0057] S4 through-hole post-processing: first, ultrasonically clean the laser-drilled glass with deionized water for 18 minutes, then soak it in 8wt.% hydrochloric acid solution for 8 minutes, and then rinse it with deionized water; then, use the chemical plating method to deposit metallic copper in the through-hole. The specific operations are as follows: first, soak the cleaned glass in an aqueous solution composed of 2wt.% stannous chloride and 4wt.% acid solution for 15 minutes to allow a layer of tin ions to be adsorbed on the glass surface; then, take out the glass, rinse it with deionized water, and soak it in an aqueous solution composed of 0.1wt.% silver nitrate and 4wt.% ammonia water for 12 minutes to reduce the adsorbed tin ions to metallic tin, thereby forming a layer of catalytically active metallic silver layer on the glass surface and the through-hole; finally, place the glass in an chemical copper plating solution composed of 15g / L copper sulfate, 30g / L potassium sodium tartrate, 10g / L sodium hydroxide and 10vol.% formaldehyde at 35°C and 0.8A / dm 2 Chemical copper plating is performed for 25 minutes at a current density of , to deposit a uniform and dense metal copper layer in the through-hole, forming a good conductive path and realizing the electrical connection between the glass and the external circuit, thus obtaining the alkali-free ceramic glass for carbon dioxide laser TGV.

[0058] Performance testing of the alkali-free ceramic glass for CO2 laser TGVs prepared in this example showed that the through-holes had uniform apertures, with an average diameter of 0.055 mm, smooth pore walls, and minimal cracks. Observation under a high-power microscope revealed no more than one crack per square centimeter of the through-hole area. The glass also exhibited excellent insulation properties, with a leakage current of less than 5 μA at 100 V. The thermal expansion coefficient was 5 × 10 -6 / ℃, meeting the application requirements in the field of electronic packaging.

[0059] Example 3

[0060] The alkali-free ceramic glass for a carbon dioxide laser TGV of this embodiment includes the following components in percentage by mass: SiO2 59.5%, Al2O3 13.6%, B2O3 10%, ZnO 2%, TiO2 1%, BaO 1.5%, SrO1%, MgO 1.5%, CaO 1.5%, Cr2O3 0.5%, ZrO2 2.9%, P2O 52%, Y2O3 0.5%, CeO2 0.4%, La2O3 0.8%, Sc2O3 0.4%, and BN 0.9%.

[0061] The method for preparing the alkali-free ceramic glass for the carbon dioxide laser TGV of this embodiment includes the following steps:

[0062] S1 Raw material preparation: Mix all raw materials evenly to obtain glass batch;

[0063] S2 melting and annealing: Place the glass batch material into a platinum-rhodium crucible and melt it at 1500°C for 2 hours while stirring to ensure that the glass liquid is uniform; cast the glass liquid into a preheated mold and anneal it at 550°C for 2 hours to obtain an alkali-free ceramic glass body;

[0064] S3 laser drilling: Before laser drilling, place the alkali-free ceramic glass blank in a vacuum of 10 -2 In an environment of Pa, low-temperature plasma treatment was performed for 11 minutes. When a carbon dioxide laser was used to laser drill holes in the alkali-free ceramic glass blank, the laser power was 50W, the pulse frequency was 20kHz, the scanning speed was 10mm / s, the spot diameter was 0.05mm, and pulse modulation technology was used. During the laser drilling process, argon gas was sprayed into the drilling area at a flow rate of 5L / min.

[0065] S4 through-hole post-processing: first, ultrasonically clean the laser-drilled glass with deionized water for 16 minutes, then soak it in 7wt.% hydrochloric acid solution for 6 minutes, and then rinse it with deionized water; then, use the chemical plating method to deposit metallic copper in the through-hole. The specific operations are as follows: first, place the cleaned glass in an aqueous solution composed of 5wt.% stannous chloride and 8wt.% acid solution and soak it for 11 minutes to allow a layer of tin ions to be adsorbed on the glass surface; then, take out the glass, rinse it with deionized water, and soak it in an aqueous solution composed of 0.3wt.% silver nitrate and 4wt.% ammonia water for 9 minutes to reduce the adsorbed tin ions to metallic tin, thereby forming a layer of catalytically active metallic silver layer on the glass surface and the through-hole; finally, place the glass in an chemical copper plating solution composed of 20g / L copper sulfate, 40g / L potassium sodium tartrate, 15g / L sodium hydroxide and 15vol.% formaldehyde at 32°C and 0.6A / dm 2 Chemical copper plating is performed for 22 minutes at a current density of , to deposit a uniform and dense metal copper layer in the through-hole, forming a good conductive path and realizing the electrical connection between the glass and the external circuit, thus obtaining the alkali-free ceramic glass for carbon dioxide laser TGV.

[0066] Performance testing of the alkali-free ceramic glass for CO2 laser TGVs prepared in this example showed that the through-holes had uniform apertures, with an average diameter of 0.056 mm, smooth pore walls, and minimal cracks. Observation under a high-power microscope revealed no more than one crack per square centimeter of the through-hole area. The glass also exhibited excellent insulation properties, with a leakage current of less than 5.5 μA at 100 V. The thermal expansion coefficient was 5.1 × 10 -6 / ℃, meeting the application requirements in the field of electronic packaging.

[0067] Example 4

[0068] The alkali-free ceramic glass for carbon dioxide laser TGV of the embodiment comprises the following components in mass percentage: SiO2 50%, Al2O3 16.6%, B2O3 13%, ZnO 3%, TiO2 1.5%, BaO 1.5%, SrO 1.5%, MgO 1.5%, CaO 1.5%, Cr2O3 0.5%, ZrO2 2.9%, P2O5 2%, Y2O3 0.5%, CeO2 0.6%, La2O3 1.2%, Sc2O3 0.6%, BN 1.6%.

[0069] The preparation method of the alkali-free ceramic glass for carbon dioxide laser TGV of the embodiment comprises the following steps:

[0070] S1 raw material preparation: uniformly mixing the raw materials to obtain a glass batch;

[0071] S2 melting and annealing: placing the glass batch into a platinum-rhodium crucible, melting at 1590℃ for 3.8h, stirring during the process to ensure the uniformity of the glass liquid; pouring the glass liquid into a preheated mold, annealing at 630℃ for 3.8h to obtain an alkali-free ceramic glass blank;

[0072] S3 laser drilling: before laser drilling, placing the alkali-free ceramic glass blank in an environment with a vacuum degree of 10 -3 Pa for 13min by using low-temperature plasma treatment; when using a carbon dioxide laser to perform laser drilling on the alkali-free ceramic glass blank, the laser power is 90W, the pulse frequency is 45kHz, the scanning speed is 28mm / s, the spot diameter is 0.03mm, the pulse modulation technology is adopted, and argon is sprayed to the drilling area at a flow rate of 9.5L / min during the laser drilling process;

[0073] S4 post-hole treatment: first, ultrasonic cleaning the glass after laser drilling with deionized water for 20min, then soaking in a 9wt.% hydrochloric acid solution for 9min, and finally rinsing with deionized water; then, depositing copper in the through hole by chemical plating, the specific operation being as follows: first, placing the cleaned glass into an aqueous solution composed of 3wt.% stannous chloride and 5wt.% acid solution for 13min to adsorb a layer of tin ions on the surface of the glass; then, taking out the glass, rinsing with deionized water, and placing it into an aqueous solution composed of 0.2wt.% silver nitrate and 3wt.% ammonia water for 11min to reduce the adsorbed tin ions to metallic tin, thereby forming a layer of catalytically active metallic silver on the surface of the glass and in the through hole; finally, placing the glass into a chemical copper plating solution composed of 18g / L copper sulfate, 35g / L potassium sodium tartrate, 12g / L sodium hydroxide and 12vol.% formaldehyde, at 38℃, at a current density of 0.9A / dm 2Chemical copper plating is performed for 28 minutes at a current density of , to deposit a uniform and dense metal copper layer in the through-hole, forming a good conductive path and realizing the electrical connection between the glass and the external circuit, thus obtaining the alkali-free ceramic glass for carbon dioxide laser TGV.

[0074] Performance testing of the alkali-free ceramic glass for CO2 laser TGVs prepared in this example showed that the through-holes had uniform apertures, with an average diameter of 0.053 mm, smooth pore walls, and minimal cracks. Observation under a high-power microscope revealed no more than one crack per square centimeter of through-hole area. The glass also exhibited excellent insulation properties, with a leakage current of less than 4 μA at 100 V. The thermal expansion coefficient was 4.8 × 10 -6 / ℃, meeting the application requirements in the field of electronic packaging.

[0075] Example 5

[0076] The alkali-free ceramic glass for a carbon dioxide laser TGV of this embodiment includes the following components in percentage by mass: SiO2 67%, Al2O3 10%, B2O3 7%, ZnO 1%, TiO2 0.5%, BaO 1%, SrO 1%, MgO 1%, CaO 1%, Cr2O3 0.5%, ZrO2 2.5%, P2O 52%, Y2O3 0.5%, CeO2 0.8%, La2O3 1.6%, Sc2O3 0.8%, and BN 1.8%.

[0077] The method for preparing the alkali-free ceramic glass for the carbon dioxide laser TGV of this embodiment includes the following steps:

[0078] S1 Raw material preparation: Mix all raw materials evenly to obtain glass batch;

[0079] S2 Melting and Annealing: Place the glass batch material into a platinum-rhodium crucible and melt it at 1600°C for 4 hours while stirring to ensure that the glass liquid is uniform; cast the glass liquid into a preheated mold and anneal it at 650°C for 4 hours to obtain an alkali-free ceramic glass body;

[0080] S3 laser drilling: Before laser drilling, place the alkali-free ceramic glass blank in a vacuum of 10 -2 In an environment of Pa, low-temperature plasma treatment was performed for 15 minutes. When a carbon dioxide laser was used to laser drill holes in the alkali-free ceramic glass blank, the laser power was 100W, the pulse frequency was 50kHz, the scanning speed was 30mm / s, the spot diameter was 0.02mm, and pulse modulation technology was used. During the laser drilling process, argon gas was sprayed into the drilling area at a flow rate of 10L / min.

[0081] S4 through-hole post-processing: first, ultrasonically clean the laser-drilled glass with deionized water for 20 minutes, then soak it in 10wt.% hydrochloric acid solution for 10 minutes, and then rinse it with deionized water; then, use the chemical plating method to deposit metallic copper in the through-hole. The specific operations are as follows: first, soak the cleaned glass in an aqueous solution composed of 3wt.% stannous chloride and 5wt.% acid solution for 15 minutes to allow a layer of tin ions to be adsorbed on the glass surface; then, take out the glass, rinse it with deionized water, and soak it in an aqueous solution composed of 0.2wt.% silver nitrate and 3wt.% ammonia water for 12 minutes to reduce the adsorbed tin ions to metallic tin, thereby forming a layer of metallic silver with catalytic activity on the glass surface and the through-hole; finally, place the glass in a chemical copper plating solution at 40°C and a speed of 1A / dm 2 Chemical copper plating is performed for 30 minutes at a current density of , to deposit a uniform and dense metal copper layer in the through-hole, forming a good conductive path and realizing the electrical connection between the glass and the external circuit, thus obtaining the alkali-free ceramic glass for carbon dioxide laser TGV.

[0082] Performance testing of the alkali-free ceramic glass for CO2 laser TGVs prepared in this example showed that the through-holes had uniform apertures, with an average diameter of 0.05 mm, smooth pore walls, and minimal cracks. Observation under a high-power microscope revealed no more than one crack per square centimeter of the through-hole area. The glass also exhibited excellent insulation properties, with a leakage current of less than 3 μA at 100 V. The thermal expansion coefficient was 4.5 × 10 -6 / ℃, meeting the application requirements in the field of electronic packaging.

[0083] Comparative Example 1

[0084] The alkali-free ceramic glass for carbon dioxide laser TGV of comparative example 1 includes the following components in mass percentage: SiO2 60.6%, Al2O3 14%, B2O3 10%, ZnO 2%, TiO2 1%, BaO 1.5%, SrO 1%, MgO 1.5%, CaO 1.5%, Cr2O3 0.5%, ZrO2 2.9%, P2O 52%, Y2O3 0.5%, CeO2 0.1%, La2O3 0.2%, Sc2O3 0.1%, and BN 0.6%.

[0085] The preparation method of the alkali-free ceramic glass for carbon dioxide laser TGV in Comparative Example 1 is the same as that in Example 1.

[0086] The performance test of the alkali-free ceramic glass for CO2 laser TGV prepared in Comparative Example 1 showed that the through-hole diameter was uneven, with an average diameter of 0.04 mm, rough hole walls, and 8 cracks per square centimeter. At a voltage of 100 V, the leakage current was 12 μA, and the thermal expansion coefficient was 7×10-6 / ℃, the performance cannot meet the requirements of electronic packaging.

[0087] This is because the combined content of CeO2, La2O3, Sc2O3, and BN in Comparative Example 1 is too low, hindering their synergistic effect. Low CeO2 content results in insufficient defect repair capability; low La2O3 content prevents effective optimization of the laser propagation path; low Sc2O3 content leads to weak grain refinement and structural stabilization; and low BN content only marginally improves thermal conductivity, leading to thermal stress concentration and numerous cracks. This affects pore size uniformity and insulation performance, and also deviates the thermal expansion coefficient from the ideal range.

[0088] Comparative Example 2

[0089] The alkali-free ceramic glass for carbon dioxide laser TGV of comparative example 2 includes the following components in mass percentage: SiO2 57.5%, Al2O3 13%, B2O3 10%, ZnO 2%, TiO2 1%, BaO 1.5%, SrO 1%, MgO 1.5%, CaO 1.5%, Cr2O3 0.5%, ZrO2 2%, P2O 52%, Y2O3 0.5%, CeO2 1.2%, La2O3 2.4%, Sc2O3 1.2%, and BN 1.2%.

[0090] The preparation method of the alkali-free ceramic glass for carbon dioxide laser TGV in Comparative Example 2 is the same as that in Example 1.

[0091] The performance test of the alkali-free ceramic glass for CO2 laser TGV prepared in Comparative Example 2 showed that the chemical stability of the glass decreased and corrosion occurred during copper plating. The pore size was uneven, with an average pore size of 0.07 mm. The pore wall had defects, with 5 cracks per square centimeter. At a voltage of 100 V, the leakage current was 9 μA, and the thermal expansion coefficient was 3.5×10 -6 / ℃, poor compatibility with other materials.

[0092] This is because the combined content of CeO2, La2O3, Sc2O3, and BN is too high, disrupting the glass's original structure and performance balance. Excessive CeO2 can alter the glass's charge balance and color; excessive La2O3 can excessively increase the refractive index, affecting laser propagation and drilling effectiveness; excessive Sc2O3 can lead to an overly dense internal structure and increased internal stress; and excessive BN can affect compatibility with other components, making the glass structure uneven, reducing chemical stability and causing copper plating corrosion. It can also cause problems with pore size, cracks, insulation performance, and thermal expansion coefficient.

[0093] Comparative Example 3

[0094] The alkali-free ceramic glass for carbon dioxide laser TGV of comparative example 3 includes the following components in mass percentage: SiO2 59.5%, Al2O3 14%, B2O3 10%, ZnO 2%, TiO2 1%, BaO 1.5%, SrO 1%, MgO 1.5%, CaO 1.5%, Cr2O3 0.5%, ZrO2 2.9%, P2O 52%, Y2O3 0.5%, CeO2 0.8%, La2O3 0.25%, Sc2O3 0.8%, and BN 0.25%.

[0095] The preparation method of the alkali-free ceramic glass for carbon dioxide laser TGV in Comparative Example 3 is the same as that in Example 1.

[0096] Performance testing of the alkali-free ceramic glass for CO2 laser TGVs prepared in Comparative Example 3 revealed poor through-hole diameter uniformity, with an average pore size of 0.062 mm. The hole walls showed significant roughness and unevenness, with numerous tiny bumps and pits. High-power microscope observation revealed five cracks per square centimeter within the through-hole area, significantly degrading the glass's insulation performance. At 100 V, the leakage current was 9 μA, and the thermal expansion coefficient was 5.6 × 10 -6 / ℃.

[0097] This is because excessive CeO2 and Sc2O3 content will make the glass structure too dense and increase internal stress. Excessive CeO2 will trigger chemical reactions within the glass, changing its chemical stability and optical properties. It may also lead to an increase in defects in local areas, making cracks more likely to form during laser drilling. At the same time, if the La2O3 and BN content is too low, La2O3 will not be able to effectively improve the glass's absorption and transmission characteristics of the laser, resulting in uneven distribution of laser energy in the glass, leading to uneven aperture and reduced drilling quality. Low BN content cannot effectively improve the glass's thermal conductivity, making it difficult to quickly disperse thermal stress, further exacerbating the formation of cracks and uneven hole walls. These factors combined lead to reduced insulation performance and abnormal thermal expansion coefficient of the glass.

[0098] Comparative Example 4

[0099] The alkali-free ceramic glass for carbon dioxide laser TGV of comparative example 4 includes the following components in mass percentage: SiO2 61.5%, Al2O3 14%, B2O3 10%, ZnO 2%, TiO2 1%, BaO 1.5%, SrO 1%, MgO 1.5%, CaO 1.5%, Cr2O3 0.5%, ZrO2 3%, P2O 52%, and Y2O3 0.5%.

[0100] The preparation method of the alkali-free ceramic glass for carbon dioxide laser TGV in Comparative Example 4 is the same as that in Example 1.

[0101] Performance tests of the alkali-free ceramic glass used in the CO2 laser TGV prepared in Comparative Example 4 showed that the through-hole diameter was uneven, with an average diameter of 0.057 mm. The hole walls were not smooth, with up to 4 cracks per square centimeter. The glass had poor laser absorption and thermal stress dispersion capabilities, with a leakage current of 8 μA at 100 V and a thermal expansion coefficient of 5.5 × 10 -6 / ℃.

[0102] This is because, in Comparative Example 4, key components such as CeO2, La2O3, Sc2O3, and BN are not added, and the performance of the glass in multiple aspects cannot be optimized. Without the addition of CeO2, defects within the glass cannot be effectively repaired, and cracks are easily generated during the laser drilling process due to stress concentration. The lack of La2O3 results in poor absorption and transmission characteristics of the glass for lasers, resulting in uneven energy distribution during drilling and difficulty in ensuring uniform apertures. The lack of Sc2O3 fails to refine the grains and stabilize the glass structure, resulting in uneven hole walls. The lack of BN results in poor thermal conductivity of the glass, preventing thermal stress from being dispersed in a timely manner, further exacerbating the formation of cracks. At the same time, the combined influence of these factors leads to a decline in the insulation performance of the glass and a change in the thermal expansion coefficient.

[0103] In summary, the ratio of the components in the present invention plays a crucial role in the performance of the prepared alkali-free ceramic glass for CO2 laser TGV. Only with a suitable ratio can high-quality glass products that meet the requirements of the electronic packaging field be obtained.

[0104] Comparative Example 5

[0105] The difference from Example 1 is that in step S3, no low-temperature plasma treatment equipment is used for pre-treatment before laser drilling.

[0106] The performance test of the alkali-free ceramic glass for CO2 laser TGV prepared in Comparative Example 5 showed that the through-hole diameter was uneven, with an average diameter of 0.059 mm, the hole wall was rough, and the number of cracks per square centimeter was 3. At a voltage of 100 V, the leakage current was 7 μA, and the thermal expansion coefficient was 5.3×10 -6 / ℃.

[0107] This is because the glass surface is not pre-treated with low-temperature plasma equipment before laser drilling, resulting in insufficient surface activity and uneven distribution of laser energy. During the drilling process, the glass's absorption and conversion efficiency of laser energy decreases, making it impossible to effectively form a regular through-hole, which in turn affects the uniformity of the aperture and the smoothness of the hole wall. It also causes uneven stress distribution within the glass, increasing the probability of cracks and affecting insulation performance and thermal expansion coefficient.

[0108] Comparative Example 6

[0109] The difference from Example 1 is that in step S3, argon gas is not sprayed during the laser drilling process.

[0110] The performance test of the alkali-free ceramic glass for CO2 laser TGV prepared in Comparative Example 6 showed that the through-hole diameter was uneven, with an average diameter of 0.056 mm. The hole wall had debris residue and was not smooth, with 4 cracks per square centimeter. At a voltage of 100 V, the leakage current was 8 μA, and the thermal expansion coefficient was 5.4×10 -6 / ℃.

[0111] This is because, without the use of argon during laser drilling, the glass surface cannot be cooled in time, leading to increased thermal stress concentration and increased cracking of the glass under thermal stress. Furthermore, the debris generated by drilling cannot be blown away in time and accumulates around the hole wall, affecting the smoothness and uniformity of the hole diameter, which in turn negatively affects the insulation properties and thermal expansion coefficient of the glass.

[0112] Comparative Example 7

[0113] The difference from Example 1 is that in step S4, after the glass is cleaned, it is directly placed in a chemical copper plating solution for chemical copper plating.

[0114] Performance testing of the alkali-free ceramic glass for CO2 laser TGVs, prepared in Comparative Example 7, revealed that the copper layer deposited within the through-holes was uneven and non-dense, with holes and gaps. At 100V, the leakage current was 10μA, preventing effective electrical connection between the glass and external circuits.

[0115] This is because, after cleaning the glass, placing it directly into the electroless copper plating solution, the debris, metal impurities, and fine particles remaining on the glass surface are not completely removed. These impurities affect the deposition of copper ions during the electroless copper plating process, hindering the uniform growth of the copper layer, causing holes and gaps in the copper layer, reducing the conductivity and density of the copper layer, and failing to meet electrical connection requirements.

Claims

1. Alkali-free ceramic glass for CO2 laser TGV, characterized by: The invention comprises the following components in percentage by mass: SiO2 50-67%, Al2O3 10-17%, B2O3 7-13%, ZnO 1-4%, TiO2 0.5-2%, BaO 0.5-3%, SrO 0.5-3%, MgO 0.5-3%, CaO 0.5-3%, Cr2O3 0.1-1%, ZrO2 2-5%, P2O5 1-3%, Y2O3 0.5-2%, CeO2+La2O3+Sc2O3+BN 2-5%, and the mass ratios of CeO2, La2O3, Sc2O3 and BN are (1-2):(2-3):(1-2):(2-4).

2. The method for preparing alkali-free ceramic glass for carbon dioxide laser TGV according to claim 1, characterized in that: The following steps are involved: S1 Raw material preparation: Mix all raw materials evenly to obtain glass batch; S2 melting and annealing: annealing the glass after melting to obtain an alkali-free ceramic glass body; S3 laser drilling: Use carbon dioxide laser to perform laser drilling on alkali-free ceramic glass blanks; S4 through-hole post-processing: The glass after laser drilling is cleaned, and then metallic copper is deposited in the through-hole by chemical plating. The specific operations are as follows: First, the cleaned glass is placed in an aqueous solution composed of 2-5wt.% stannous chloride and 4-8wt.% acid solution and soaked for 10-15 minutes to allow a layer of tin ions to be adsorbed on the glass surface; then, the glass is taken out, rinsed with deionized water, and placed in an aqueous solution composed of 0.1-0.3wt.% silver nitrate and 2-4wt.% ammonia water and soaked for 8-12 minutes to reduce the adsorbed tin ions to metallic tin, thereby forming a layer of metallic silver with catalytic activity on the glass surface and the through-hole; finally, the glass is placed in an electroless copper plating solution at 30-40°C and a temperature of 0.5-1A / dm 2 Chemical copper plating is performed for 20-30 minutes at a current density of , and a uniform and dense metal copper layer is deposited in the through hole to obtain the alkali-free ceramic glass for carbon dioxide laser TGV.

3. The method for preparing alkali-free ceramic glass for carbon dioxide laser TGV according to claim 2, characterized in that: In step S2, the smelting temperature is 1500-1600°C and the time is 2-4 hours.

4. The method for preparing alkali-free ceramic glass for carbon dioxide laser TGV according to claim 2, characterized in that: In step S2, the annealing temperature is 550-650° C. and the time is 2-4 hours.

5. The method for preparing alkali-free ceramic glass for carbon dioxide laser TGV according to claim 2, characterized in that: In step S3, the laser power of the carbon dioxide laser is 50-100 W, the pulse frequency is 20-50 kHz, the scanning speed is 10-30 mm / s, and the spot diameter is 0.02-0.05 mm.

6. The method for preparing alkali-free ceramic glass for carbon dioxide laser TGV according to claim 2, characterized in that: In step S3, before laser drilling, the alkali-free ceramic glass body is pretreated by placing it in a vacuum environment and performing surface treatment on it using a low-temperature plasma treatment device for 10-15 minutes.

7. The method for preparing alkali-free ceramic glass for carbon dioxide laser TGV according to claim 2, characterized in that: In step S3, during the laser drilling process, a protective gas is sprayed toward the drilling area.

8. The method for preparing alkali-free ceramic glass for carbon dioxide laser TGV according to claim 7, characterized in that: The protective gas is argon with a flow rate of 5-10L / min.

9. The method for preparing alkali-free ceramic glass for carbon dioxide laser TGV according to claim 2, characterized in that: In step S4, during cleaning, first use deionized water for ultrasonic cleaning for 15-20 minutes, then soak in acid solution for 5-10 minutes, and then rinse with deionized water.

10. The method for preparing alkali-free ceramic glass for carbon dioxide laser TGV according to claim 2, characterized in that: In step S4, the chemical copper plating solution includes 15-20 g / L copper sulfate, 30-40 g / L potassium sodium tartrate, 10-15 g / L sodium hydroxide and 10-15 vol.% formaldehyde.