High-strength high-flatness glass substrate for chip packaging and method of manufacturing the same

Abstract

The application provides a kind of high-strength high flatness glass substrate for chip packaging and a preparation method thereof, relating to the technical field of chip packaging glass, the raw material composition of the glass substrate includes silicon dioxide, aluminum oxide, boron oxide, magnesium oxide, calcium oxide, yttrium oxide, composite clarifying agent, reinforcing agent, surface modifier, thermal stabilizer;The composite clarifying agent is a mixture of sodium sulfate and antimony dioxide;The reinforcing agent is a mixture of zirconium oxide and titanium dioxide;The surface modifier is a mixture of zinc oxide and strontium oxide;The glass substrate is polished by polishing liquid: the raw material composition of the polishing liquid includes silicon oxide, aminotrimethylenephosphonic acid, composite dispersing agent, buffer, deionized water;The composite dispersing agent is a mixture of sodium polyacrylate and sodium dodecylbenzenesulfonate.The glass substrate for chip packaging prepared by the application has excellent mechanical strength and flatness.

Description

Technical Field

[0001] This invention relates to the field of chip packaging glass technology, specifically to a high-strength, high-flatness glass substrate for chip packaging and its preparation method. Background Technology

[0002] In today's rapidly developing electronic products market, the advancement of chip technology is indispensable. However, the corresponding packaging technology and electrical connections limit chip performance, making chip packaging crucial for chip performance. Traditional chip packaging materials include ceramics and organic resins. However, ceramic substrates have high resistance or high dielectric constants, making it difficult to mount high-performance, high-frequency semiconductor components. Organic resin substrates have poor thermal expansion coefficient matching and are difficult to implement high-density wiring. Glass, as a chip packaging substrate, has the characteristics of low dielectric constant and low dielectric loss factor, which can reduce signal transmission loss. By adjusting the composition formula, the thermal expansion coefficient can be adjusted to be close to that of the chip, and the strength and heat resistance can be increased to improve packaging reliability and stability. By improving the polishing process to increase flatness, the interconnect density of the glass can be increased, meeting the high-density interconnect requirements of the chip.

[0003] Chinese patent CN120518330A discloses a high-strength multifunctional glass panel and its processing technology, including the following steps: S1, substrate forming and pretreatment; S2, microstructure processing: using ultraviolet nanoimprinting technology to imprint honeycomb-shaped microstructures on the substrate surface, followed by ultraviolet curing; S3, preparation of an embedded conductive-thermal insulating composite layer; S4, multifunctional composite coating; S5, lamination and strengthening. Although the glass panel obtained by this patent has an increased bending strength of 150-180MPa, its aerogel has low mechanical strength, compressive strength <20kPa, microstructure layer thickness of only 10-30nm, and insufficient wear resistance, making it difficult to meet the requirements of high-strength functional glass.

[0004] Chinese patent CN119371116A discloses a method for processing ultra-thin high-temperature colored enamel glass with high flatness, including the following steps: S1, providing an ultra-thin glass substrate with a thickness of less than 1.6 mm and colored enamel material; S2, performing ultrasonic cleaning and chemical etching on the glass substrate; S3, uniformly coating the colored enamel material onto the surface of the substrate using precision screen printing technology; S4, generating a temperature firing curve according to the type, size, thickness of the glass substrate and the characteristics of the enamel material, including a preheating zone (300-500℃), a main sintering zone (600-700℃), a high-temperature forming zone (700-800℃), and a cooling zone (target cooling rate 400-600℃ / h), wherein the rapid cooling zone achieves rapid and uniform cooling by controlling the airflow speed, direction, angle, and type (such as CO2 or N2) through multiple airflow nozzles; S5, after firing, performing mechanical polishing (5-10 minutes) and chemical polishing (10-20 minutes) in sequence to eliminate minor unevenness and obtain ultra-thin high-temperature colored enamel glass. Although this method significantly improves the flatness of the glass (error ≤1μm), the multiple polishing and high-temperature rapid cooling processes during operation can lead to local stress concentration, affecting its impact resistance and long-term durability. In particular, it is prone to microcracks or deformation in high-temperature or large temperature difference environments.

[0005] The above analysis reveals the following technical shortcomings of existing glass substrates used for chip packaging: insufficient mechanical properties, and a trade-off between high flatness and resistance to temperature variations and deformation. Therefore, the fabrication of high-strength, high-flatness glass substrates is of paramount practical significance for chip development. Summary of the Invention

[0006] In order to solve the above-mentioned problems in the prior art, the present invention provides a high-strength and high-flatness glass substrate for chip packaging and its preparation method, and achieves the following objectives: improving the strength, flatness and interconnection density of the glass substrate for chip packaging.

[0007] To achieve the above objectives, the following technical solution is adopted:

[0008] A method for preparing a high-strength, high-flatness glass substrate for chip packaging, characterized by including the following steps: preparation of a reinforcing agent, melting, forming and strengthening, preparation of a polishing slurry, precision polishing, TGV fabrication, and metallization.

[0009] Preparation of the reinforcing agent: Zirconia and titanium dioxide are mixed evenly to obtain the reinforcing agent.

[0010] Furthermore, the mass ratio of zirconium oxide to titanium dioxide is (60-80):(40-20).

[0011] The melting process involves uniformly mixing silicon dioxide, aluminum oxide, boron oxide, magnesium oxide, calcium oxide, yttrium oxide, composite clarifying agent, reinforcing agent, surface modifier, and heat stabilizer, then placing the mixture into a glass furnace for stepwise heating and holding, followed by cooling and holding to melt it into a high-temperature glass melt.

[0012] Furthermore, the raw materials used have the following weight composition: 65-80 parts silicon dioxide, 15-22 parts aluminum oxide, 10-15 parts boron oxide, 3-15 parts magnesium oxide, 6-10 parts calcium oxide, 2-4 parts yttrium oxide, 4-8 parts composite clarifying agent, 3-7 parts reinforcing agent, 3-9 parts surface modifier, and 2.5-5.5 parts heat stabilizer. The composite clarifying agent is a mixture of sodium sulfate and antimony dioxide in a mass ratio of (40-60):(60-40); the surface modifier is a mixture of zinc oxide and strontium oxide in a mass ratio of (40-60):(60-40); and the heat stabilizer is phosphorus pentoxide.

[0013] Furthermore, the stepped heating and holding process involves first heating to 1100-1300℃ at a rate of 3-6℃ / min and holding for 30-60 minutes, then heating to 1550-1700℃ at a rate of 2-4℃ / min and holding for 2-5 hours.

[0014] Furthermore, the melting process involves uniformly mixing silicon dioxide, aluminum oxide, boron oxide, magnesium oxide, calcium oxide, yttrium oxide, composite clarifying agent, reinforcing agent, surface modifier, and heat stabilizer, then placing the mixture into a glass melting furnace for stepwise heating and holding at that temperature. The temperature is then lowered to 1420-1500℃ and held for 30-50 minutes to melt the mixture into a high-temperature glass melt.

[0015] The forming and strengthening process involves preheating the glass forming mold, pouring high-temperature molten glass onto the mold to obtain a glass sheet, followed by annealing, and then chemical strengthening treatment.

[0016] Furthermore, the chemical strengthening treatment involves immersing the annealed glass sheet in potassium nitrate molten salt at 400-480°C for 2-8 hours, allowing sodium ions on the glass surface to exchange with potassium ions in the molten salt, forming a surface compressive stress layer.

[0017] Furthermore, the forming and strengthening process involves: preheating the glass forming mold to 650-750℃, then casting the high-temperature molten glass onto the mold to obtain a glass sheet. The glass sheet is then annealed at 580-630℃ for 1.5-3 hours. After annealing, a chemical strengthening treatment is performed, specifically by immersing the annealed glass sheet in potassium nitrate molten salt at 400-480℃ for 2-8 hours, allowing sodium ions on the glass surface to exchange with potassium ions in the molten salt, forming a surface compressive stress layer.

[0018] Preparation of the polishing slurry: Silicon oxide, aminotrimethylphosphonic acid, composite dispersant, buffer, and deionized water are mixed evenly to obtain the polishing slurry.

[0019] Furthermore, the raw materials used have the following composition by weight: 40-70 parts silicon dioxide, 15-30 parts aminotrimethylphosphonic acid, 8-18 parts composite dispersant, 5-10 parts buffer, and 60-90 parts deionized water. The composite dispersant is a mixture of sodium polyacrylate and sodium dodecylbenzenesulfonate, with a mass ratio of (40-60):(60-40); the buffer is a mixture of citric acid and ammonia solution, with a mass ratio of (8-25):(5-15); and the ammonia solution has a mass fraction of 25%.

[0020] The precision polishing process involves using a double-sided grinding and polishing machine and a polyurethane polishing pad to perform chemical mechanical polishing on the chemically tempered glass substrate semi-finished product. After polishing, the product is washed with ultrapure water and dried to obtain the polished glass substrate semi-finished product.

[0021] Furthermore, the precision polishing involves using a double-sided grinding and polishing machine and a polyurethane polishing pad to perform chemical mechanical polishing on the chemically tempered glass substrate semi-finished product. The spindle speed is controlled at 70-100 rpm, the polishing disc speed at 30-50 rpm, the polishing liquid droplet rate at 0.6-1.2 mL / min, and the polishing time at 3.5-5 hours. After polishing, the product is washed with ultrapure water and dried to obtain the polished glass substrate semi-finished product.

[0022] The TGV fabrication process involves using a femtosecond laser to fabricate a TGV pattern on a polished glass substrate semi-finished product. The pattern is then scanned on the substrate to form a modified trajectory, and finally etched in an HF solution to form a TGV array.

[0023] Furthermore, the femtosecond laser parameters are set with a wavelength of 1030 nm and a pulse length of 300 fs.

[0024] Furthermore, the TGV fabrication process involves using a femtosecond laser to fabricate a TGV on a polished glass substrate semi-finished product, scanning the substrate to form a modified trajectory, and then immersing it in a 10% (mass percentage) HF solution for etching at 40°C for 30 minutes to form a TGV array with an aspect ratio of 10:1.

[0025] The metallization process involves filling the TGV with conductive silver paste through screen printing, followed by sintering to form vertical interconnects, resulting in a glass substrate for chip packaging.

[0026] The beneficial effects of this invention are as follows:

[0027] 1. In this invention, titanium dioxide in the reinforcing agent is an intermediate oxide that can form bridging oxygen bonds with SiO2 and Al2O3 in the glass network, fill the gaps in the glass network, reduce structural defects, and at the same time inhibit the agglomeration of zirconium oxide particles, ensuring that the reinforcing agent is uniformly distributed in the matrix; both zirconium oxide and titanium dioxide have low coefficient of thermal expansion characteristics, which work synergistically with the glass matrix components to reduce the overall coefficient of thermal expansion.

[0028] The polishing slurry is composed of silica, aminotrimethylphosphonic acid, composite dispersant, and buffer. Sodium polyacrylate in the composite dispersant prevents silica abrasive from agglomerating through electrostatic repulsion, while sodium dodecylbenzenesulfonate reduces the interfacial tension between the abrasive and the glass surface. The two work together to ensure that the abrasive is uniformly suspended in the polishing slurry, avoiding local over-grinding or under-grinding. Silica abrasive provides mechanical abrasive force, while aminotrimethylphosphonic acid can chelate metal ions on the glass surface and slightly dissolve the protruding parts of the glass surface, achieving a synergistic effect of mechanical abrasive and chemical dissolution, effectively reducing surface roughness.

[0029] Femtosecond lasers have short pulse durations, concentrating energy in specific areas inside the glass. Through multiphoton absorption, they modify the local glass structure without damaging the surface flatness. The modified glass area increases the etching rate of HF acid, enabling precise etching. The TGV array can accommodate more conductive silver paste-filled channels. Combined with screen printing metallization technology, it achieves high-density vertical interconnection between the chip and the substrate, meeting the wiring requirements of high-end chips.

[0030] 2. By optimizing the synergistic effect of glass components and reinforcing agents, this invention significantly improves the mechanical properties and thermal stability of the glass matrix, enabling it to maintain structural integrity and functional reliability under high temperature and high stress environments.

[0031] 3. The chemical strengthening process used in this invention involves ion exchange in potassium nitrate molten salt to form a high compressive stress layer on the glass surface, which greatly improves the mechanical strength of the glass substrate, with a bending strength of 310-335 MPa.

[0032] 4. This invention ensures the uniformity and stability of the polishing process by using a specific polishing fluid, thereby obtaining a highly flat glass surface with a surface roughness Ra < 0.3 nm.

[0033] 5. The high-strength, high-flatness chip packaging glass substrate prepared by this invention has high mechanical strength, a bending strength of 310-335 MPa, and a low coefficient of thermal expansion as low as 3.7-4.0 × 10⁻⁶ MPa. -7 / ℃, surface roughness <0.3nm, fully meeting the requirements of high-end chip packaging. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0035] Example 1:

[0036] A high-strength, high-flatness glass substrate for chip packaging, comprising the following raw materials:

[0037] 72 parts silicon dioxide, 15 parts aluminum oxide, 12 parts boron oxide, 9 parts magnesium oxide, 8 parts calcium oxide, 3 parts yttrium oxide, 6 parts composite clarifying agent, 5 parts reinforcing agent, 3 parts surface modifier, and 3 parts heat stabilizer. All the above parts are by weight.

[0038] The composite clarifying agent is a mixture of sodium sulfate and antimony dioxide in a mass ratio of 50:50;

[0039] The surface modifier is a mixture of zinc oxide and strontium oxide in a mass ratio of 40:60;

[0040] The heat stabilizer is phosphorus pentoxide.

[0041] A method for preparing a high-strength, high-flatness glass substrate for chip packaging includes the following steps:

[0042] Step 1: Preparation of the reinforcing agent

[0043] A reinforcing agent was prepared by mixing zirconium oxide and titanium dioxide at a mass ratio of 70:30.

[0044] Step 2, Melting

[0045] After uniformly mixing silica, alumina, boron oxide, magnesium oxide, calcium oxide, yttrium oxide, composite clarifying agent, reinforcing agent, surface modifier, and heat stabilizer, the mixture is placed in a glass melting furnace. The temperature is raised to 1150℃ at a rate of 4℃ / min and held for 40 minutes. Then, the temperature is raised to 1680℃ at a rate of 2.5℃ / min and held for 3.5 hours. Finally, the temperature is lowered to 1500℃ and held for 30 minutes to melt the mixture into a high-temperature glass melt.

[0046] Step 3: Molding and Strengthening

[0047] After preheating the glass forming mold to 720℃, the high-temperature glass melt is poured into the mold to obtain a glass sheet. The glass sheet is then annealed at 630℃ for 2 hours. After annealing, a chemical strengthening treatment is performed, specifically by immersing the annealed glass sheet in potassium nitrate molten salt at 450℃ for 6 hours, and then allowing it to cool naturally.

[0048] Step 4: Preparation of polishing slurry

[0049] Prepare the polishing liquid according to the following formula, including the following ingredients:

[0050] 40 parts silicon dioxide, 15 parts aminotrimethylphosphonic acid, 12 parts composite dispersant, 5 parts buffer, and 65 parts deionized water. All the above parts are by weight.

[0051] The composite dispersant is a mixture of sodium polyacrylate and sodium dodecylbenzenesulfonate, with a mass ratio of 60:40.

[0052] The buffer is a mixture of citric acid and ammonia solution, used to maintain the pH at 9.5; the ammonia solution has a mass fraction of 25%.

[0053] Step 5: Precision polishing

[0054] Chemical mechanical polishing (CMP) was performed on the chemically tempered glass substrate semi-finished product using a double-sided grinding and polishing machine and a polyurethane polishing pad. The spindle speed was controlled at 70 rpm, the polishing disc speed at 35 rpm, the polishing liquid droplet rate at 0.7 mL / min, and the polishing time at 3.5 h. After polishing, the product was washed with ultrapure water and dried to obtain the polished glass substrate semi-finished product.

[0055] Step 6: TGV Production

[0056] The polished glass substrate semi-finished product is fabricated using a femtosecond laser to perform TGV, and a modification trajectory is formed by scanning on the substrate. The femtosecond laser wavelength is 1030nm and the pulse length is 300fs. Then, it is placed in a 10% (mass percentage) HF solution and etched at 40°C for 30 minutes to form a TGV array with an aspect ratio of 10:1.

[0057] Step 7, Metallization

[0058] Conductive silver paste is filled into the TGV through screen printing, and vertical interconnects are formed by sintering to obtain a glass substrate for chip packaging.

[0059] Example 2:

[0060] A high-strength, high-flatness glass substrate for chip packaging, comprising the following raw materials:

[0061] 72 parts silicon dioxide, 18 parts aluminum oxide, 12 parts boron oxide, 9 parts magnesium oxide, 8 parts calcium oxide, 3 parts yttrium oxide, 6 parts composite clarifying agent, 5 parts reinforcing agent, 6 parts surface modifier, and 4 parts heat stabilizer. All the above parts are by weight.

[0062] The composite clarifying agent is a mixture of sodium sulfate and antimony dioxide in a mass ratio of 50:50;

[0063] The surface modifier is a mixture of zinc oxide and strontium oxide in a mass ratio of 40:60;

[0064] The heat stabilizer is phosphorus pentoxide.

[0065] A method for preparing a high-strength, high-flatness glass substrate for chip packaging includes the following steps:

[0066] Step 1: Preparation of the reinforcing agent

[0067] A reinforcing agent was prepared by mixing zirconium oxide and titanium dioxide at a mass ratio of 65:35.

[0068] Step 2, Melting

[0069] After uniformly mixing silica, alumina, boron oxide, magnesium oxide, calcium oxide, yttrium oxide, composite clarifying agent, reinforcing agent, surface modifier, and heat stabilizer, the mixture is placed in a glass melting furnace. The temperature is raised to 1200℃ at a rate of 5℃ / min and held for 50 minutes. Then, the temperature is raised to 1650℃ at a rate of 3℃ / min and held for 4 hours. Finally, the temperature is lowered to 1480℃ and held for 40 minutes to melt the mixture into a high-temperature glass melt.

[0070] Step 3: Molding and Strengthening

[0071] After preheating the glass forming mold to 700℃, the high-temperature molten glass is poured into the mold to obtain a glass sheet. The glass sheet is then annealed at 620℃ for 2.5 hours. After annealing, a chemical strengthening treatment is performed, specifically by immersing the annealed glass sheet in potassium nitrate molten salt at 460℃ for 5 hours, and then allowing it to cool naturally.

[0072] Step 4: Preparation of polishing slurry

[0073] Prepare the polishing solution according to the following formula, including the following ingredients:

[0074] 50 parts of silicon dioxide, 20 parts of aminotrimethylphosphonic acid, 15 parts of composite dispersant, 5 parts of buffer, and 65 parts of deionized water. All the above parts are by weight.

[0075] The composite dispersant is a mixture of sodium polyacrylate and sodium dodecylbenzenesulfonate, with a mass ratio of 50:50.

[0076] The buffer is a mixture of citric acid and ammonia solution, used to maintain the pH at 9.5; the ammonia solution has a mass fraction of 25%.

[0077] Step 5: Precision polishing

[0078] Chemical mechanical polishing (CMP) was performed on the chemically tempered glass substrate semi-finished product using a double-sided grinding and polishing machine and a polyurethane polishing pad. The spindle speed was controlled at 80 rpm, the polishing disc speed at 40 rpm, the polishing liquid droplet rate at 0.8 ml / min, and the polishing time at 4 hours. After polishing, the product was washed with ultrapure water and dried to obtain the polished glass substrate semi-finished product.

[0079] Step 6: TGV Production

[0080] The polished glass substrate semi-finished product is fabricated using a femtosecond laser to perform TGV, and a modification trajectory is formed by scanning on the substrate. The femtosecond laser wavelength is 1030nm and the pulse length is 300fs. Then, it is placed in a 10% (mass percentage) HF solution and etched at 40°C for 30 minutes to form a TGV array with an aspect ratio of 10:1.

[0081] Step 7, Metallization

[0082] Conductive silver paste is filled into the TGV through screen printing, and vertical interconnects are formed by sintering to obtain a glass substrate for chip packaging.

[0083] Example 3:

[0084] A high-strength, high-flatness glass substrate for chip packaging, comprising the following raw materials:

[0085] 75 parts silicon dioxide, 20 parts aluminum oxide, 10 parts boron oxide, 5 parts magnesium oxide, 7 parts calcium oxide, 2.5 parts yttrium oxide, 4 parts composite clarifying agent, 7 parts reinforcing agent, 8 parts surface modifier, and 5 parts heat stabilizer. All the above parts are by weight.

[0086] The composite clarifying agent is a mixture of sodium sulfate and antimony dioxide in a mass ratio of 45:55;

[0087] The surface modifier is a mixture of zinc oxide and strontium oxide in a mass ratio of 60:40;

[0088] The heat stabilizer is phosphorus pentoxide.

[0089] A method for preparing a high-strength, high-flatness glass substrate for chip packaging includes the following steps:

[0090] Step 1: Preparation of the reinforcing agent

[0091] A reinforcing agent was prepared by mixing zirconium oxide and titanium dioxide at a mass ratio of 75:25.

[0092] Step 2, Melting

[0093] After uniformly mixing silica, alumina, boron oxide, magnesium oxide, calcium oxide, yttrium oxide, composite clarifying agent, reinforcing agent, surface modifier, and heat stabilizer, the mixture is placed in a glass melting furnace. The temperature is raised to 1250°C at a rate of 4°C / min and held for 35 minutes. Then, the temperature is raised to 1620°C at a rate of 3.5°C / min and held for 3 hours. Finally, the temperature is lowered to 1450°C and held for 45 minutes to melt the mixture into a high-temperature glass melt.

[0094] Step 3: Molding and Strengthening

[0095] After preheating the glass forming mold to 680℃, the high-temperature glass melt is poured into the mold to obtain a glass sheet. The glass sheet is then annealed at 600℃ for 2 hours. After annealing, a chemical strengthening treatment is performed, specifically by immersing the annealed glass sheet in potassium nitrate molten salt at 470℃ for 4 hours, and then allowing it to cool naturally.

[0096] Step 4: Preparation of polishing slurry

[0097] Prepare the polishing solution according to the following formula, including the following ingredients:

[0098] 60 parts of silicon dioxide, 25 parts of aminotrimethylphosphonic acid, 10 parts of composite dispersant, 5 parts of buffer, and 80 parts of deionized water. All the above parts are by weight.

[0099] The composite dispersant is a mixture of sodium polyacrylate and sodium dodecylbenzenesulfonate, with a mass ratio of 50:50.

[0100] The buffer is a mixture of citric acid and ammonia solution, used to maintain the pH at 9.5; the ammonia solution has a mass fraction of 25%.

[0101] Step 5: Precision polishing

[0102] Chemical mechanical polishing (CMP) was performed on the chemically tempered glass substrate semi-finished product using a double-sided grinding and polishing machine and a polyurethane polishing pad. The spindle speed was controlled at 90 rpm, the polishing disc speed at 45 rpm, the polishing liquid droplet rate at 1.0 ml / min, and the polishing time at 4.5 hours. After polishing, the product was washed with ultrapure water and dried to obtain the polished glass substrate semi-finished product.

[0103] Step 6: TGV Production

[0104] The polished glass substrate semi-finished product is fabricated using a femtosecond laser to perform TGV, and a modification trajectory is formed by scanning on the substrate. The femtosecond laser wavelength is 1030nm and the pulse length is 300fs. Then, it is placed in a 10% (mass percentage) HF solution and etched at 40°C for 30 minutes to form a TGV array with an aspect ratio of 10:1.

[0105] Step 7, Metallization

[0106] Conductive silver paste is filled into the TGV through screen printing, and vertical interconnects are formed by sintering to obtain a glass substrate for chip packaging.

[0107] Comparative Example 1: Based on Example 1, step 1 and the addition of titanium dioxide to the reinforcing agent are the same as in Example 1. The specific operations are as follows:

[0108] Step 1: Preparation of the reinforcing agent

[0109] Zirconia was used as a reinforcing agent.

[0110] Steps 2, 3, 4, 5, 6, and 7 are the same as in Example 1.

[0111] Comparative Example 2: Based on Example 1, aminotrimethylphosphonic acid and composite dispersant were not added in the preparation of the polishing solution in step 4. The specific operation is as follows:

[0112] Steps 1, 2, and 3 are the same as in Example 1;

[0113] Step 4: Preparation of polishing slurry

[0114] Prepare the polishing liquid according to the following formula, including the following ingredients:

[0115] 40 parts silica, 5 parts buffer, and 92 parts deionized water. All parts are by weight.

[0116] The buffer is a mixture of citric acid and ammonia water, used to maintain the pH value at 9.5; the ammonia water solution has a mass fraction of 25%.

[0117] Steps 5, 6, and 7 are the same as in Example 1.

[0118] Performance testing and comparative analysis:

[0119] The glass substrates for chip packaging obtained in Examples 1, 2, and 3, and Comparative Examples 1 and 2, were tested for properties such as bending strength, coefficient of thermal expansion, surface roughness, and surface flatness.

[0120] 1. Bending strength: The bending strength shall be tested in accordance with the method in GB / T6569-2006.

[0121] 2. Thermal expansion coefficient test: According to ASTM E228-1985, "Test method for determining the linear thermal expansion of solid materials by means of a transparent quartz dilatometer", the thermal mechanical analyzer (TMA) was used to measure the coefficient of thermal expansion (50-350℃ range).

[0122] 3. Surface roughness (Ra): Surface roughness was measured using a Dimention-3100 atomic force microscope (AFM).

[0123] 4. Surface flatness: The surface flatness is tested using an optical plane scanner according to the method in GB / T2831-2009 "Test Methods for Optical Plane Glass".

[0124] The results are shown in Table 1:

[0125] Table 1

[0126]

[0127] As can be seen from the data in Table 1, the flexural strength of this invention reaches 310-335 MPa, and the coefficient of thermal expansion is 3.7 × 10⁻⁶. -7 / ℃-3.9×10 -7 The surface roughness is as low as 0.25-0.29 nm and the surface flatness is within 1.6 μm at ℃, which indicates that the glass substrate prepared by the present invention has excellent properties of high strength and high flatness, and does not affect the thermal stability of the glass material.

[0128] Obviously, there are many other possible implementation methods under the concept of this invention. It should be stated here that any changes made under the inventive concept of this invention will fall within the protection scope of this invention.

Claims

1. A method for preparing a high-strength, high-flatness glass substrate for chip packaging, characterized in that: This includes the preparation, melting, forming and strengthening of reinforcing agents, preparation of polishing slurry, precision polishing, TGV fabrication, and metallization steps. Preparation of the reinforcing agent: Zirconia and titanium dioxide are mixed evenly to obtain the reinforcing agent; The melting process involves uniformly mixing silicon dioxide, aluminum oxide, boron oxide, magnesium oxide, calcium oxide, yttrium oxide, a composite clarifying agent, a reinforcing agent, a surface modifier, and a heat stabilizer, then placing the mixture into a glass furnace for step-by-step heating and holding, followed by cooling and holding to melt it into a high-temperature glass melt. The composite clarifying agent is a mixture of sodium sulfate and antimony dioxide in a mass ratio of (40-60):(60-40); the surface modifier is a mixture of zinc oxide and strontium oxide in a mass ratio of (40-60):(60-40); and the heat stabilizer is phosphorus pentoxide. The forming and strengthening process involves preheating the glass forming mold, pouring high-temperature molten glass onto the mold to obtain a glass sheet, followed by annealing, and then chemical strengthening treatment. Preparation of the polishing slurry: Silicon oxide, aminotrimethylphosphonic acid, composite dispersant, buffer, and deionized water are mixed evenly to obtain the polishing slurry; the composite dispersant is a mixture of sodium polyacrylate and sodium dodecylbenzenesulfonate, with a mass ratio of (40-60):(60-40). The precision polishing involves using a double-sided grinding and polishing machine and a polyurethane polishing pad to perform chemical mechanical polishing on the chemically tempered glass substrate semi-finished product; after polishing, the product is washed with ultrapure water and dried to obtain the polished glass substrate semi-finished product. The TGV fabrication process involves using a femtosecond laser to fabricate a TGV on a polished glass substrate semi-finished product, scanning the substrate to form a modified trajectory, and then etching it in an HF solution to form a TGV array. The metallization process involves filling the TGV with conductive silver paste through screen printing, followed by sintering to form vertical interconnects, resulting in a glass substrate for chip packaging.

2. The method for preparing a high-strength, high-flatness glass substrate for chip packaging according to claim 1, characterized in that: The mass ratio of zirconium oxide to titanium dioxide is (60-80):(40-20).

3. The method for preparing a high-strength, high-flatness glass substrate for chip packaging according to claim 1, characterized in that: In the melting step, the raw materials are composed of the following parts by weight: 65-80 parts silicon dioxide, 15-22 parts aluminum oxide, 10-15 parts boron oxide, 3-15 parts magnesium oxide, 6-10 parts calcium oxide, 2-4 parts yttrium oxide, 4-8 parts composite clarifying agent, 3-7 parts reinforcing agent, 3-9 parts surface modifier, and 2.5-5.5 parts heat stabilizer.

4. The method for preparing a high-strength, high-flatness glass substrate for chip packaging according to claim 1, characterized in that: The stepped heating and holding process involves first heating to 1100-1300℃ at a rate of 3-6℃ / min and holding for 30-60 minutes, then heating to 1550-1700℃ at a rate of 2-4℃ / min and holding for 2-5 hours.

5. The method for preparing a high-strength, high-flatness glass substrate for chip packaging according to claim 1, characterized in that: The chemical strengthening treatment involves immersing the annealed glass sheet in potassium nitrate molten salt at 400-480℃ for 2-8 hours, allowing sodium ions on the glass surface to exchange with potassium ions in the molten salt, forming a surface compressive stress layer.

6. The method for preparing a high-strength, high-flatness glass substrate for chip packaging according to claim 1, characterized in that: In the preparation step of the polishing liquid, the raw materials are composed of the following parts by weight: 40-70 parts of silicon dioxide, 15-30 parts of aminotrimethylphosphonic acid, 8-18 parts of composite dispersant, 5-10 parts of buffer, and 60-90 parts of deionized water.

7. The method for preparing a high-strength, high-flatness glass substrate for chip packaging according to claim 1, characterized in that: The buffer is a mixture of citric acid and ammonia solution in a mass ratio of (8-25):(5-15); the ammonia solution has a mass fraction of 25%.

8. The method for preparing a high-strength, high-flatness glass substrate for chip packaging according to claim 1, characterized in that: The femtosecond laser parameters are set with a wavelength of 1030 nm and a pulse length of 300 fs.

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