A CaO-B2O3-SiO2-CaF2 glass-ceramic and its preparation method and application

Abstract

A CaO-B2O3-SiO2-CaF2 glass-ceramic and its preparation method and application belong to the technical field of chip-type and integrated passive components. The present invention provides a CaO-B2O3-SiO2-CaF2 glass-ceramic comprising the following components in molar percentage: CaO 40-50mol%, B2O3 3-18mol%, SiO2 35-45mol%, and CaF2 5-18mol%. The particle size D of the CaO-B2O3-SiO2-CaF2 glass-ceramic is 200-3000 nm. 50 The nanostructured CaO-B2O3-SiO2-CaF2 glass-ceramics has a low softening point, a wide sintering window, a high degree of densification, and excellent microwave dielectric properties, and is even better compatible with co-firing electrodes.

Description

Technical Field

[0001] The present invention belongs to the technical field of chip-type and integrated passive components, and in particular relates to a CaO-B2O3-SiO2-CaF2 glass-ceramic and a preparation method and application thereof. Background Art

[0002] LTCC technology offers high packaging density, high reliability, and low cost, making it an optimal solution for achieving high-density three-dimensional packaging of passive components. This technology requires a packaging substrate that is compatible with co-firing metal electrodes (gold, silver, copper), exhibits high densification, high flexural strength, and excellent microwave dielectric properties. Currently, glass / ceramic composites and microcrystalline glass meet the requirements for LTCC packaging substrates. Microcrystalline glass precipitates a large amount of ceramic crystals during the sintering process. Compared to glass / ceramic composites, microcrystalline glass has less residual amorphous glass and exhibits superior high-frequency characteristics. CaO-B2O3-SiO2 glass, which primarily precipitates CaSiO3 and CaB2O4 crystals after sintering, exhibits excellent microwave performance, making it widely used in the LTCC field. However, CaO-B2O3-SiO2 glass has a high softening point and a very narrow sintering window. When co-firing with electrodes, the resulting sintering shrinkage mismatch creates significant stress, which can easily lead to substrate cracking and delamination. Developing CaO-B2O3-SiO2 glass with a lower softening point, broadening the sintering window, and further improving its compatibility with co-firing electrodes are of great significance to enhancing the application prospects of CaO-B2O3-SiO2 glass in the LTCC field.

[0003] Existing CaO-B2O3-SiO2 glass has excellent high-frequency dielectric properties after sintering, but its softening point is high, the sintering window is narrow, and it is not compatible with electrode co-firing. By selecting two CaO-B2O3-SiO2 glasses with different softening points and mixing them, the glass with a low softening point is used to promote sintering density, and the glass with a high softening point is used to slow the sintering speed, thereby improving the compatibility of the CaO-B2O3-SiO2 substrate and the electrode co-firing process. However, this solution cannot significantly reduce the softening point of the CaO-B2O3-SiO2 glass, and the sintering window of the substrate material after mixing the two CaO-B2O3-SiO2 glasses is still narrow. Summary of the Invention

[0004] In response to the aforementioned deficiencies in the prior art, the present invention aims to provide a CaO-B2O3-SiO2-CaF2 glass-ceramic, its preparation method, and its application. The present invention is directed to developing a glass-ceramic for low-temperature co-fired ceramics (LTCCs) that exhibits a low softening temperature, a wide sintering window, a high degree of densification, and excellent microwave dielectric properties, promising promising applications in LTCC packaging.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A CaO-B2O3-SiO2-CaF2 glass-ceramics, characterized by comprising the following components in molar percentage: CaO 40-50mol%, B2O3 3-18mol%, SiO2 35-45mol%, and CaF2 5-18mol%.

[0007] The CaO-B2O3-SiO2-CaF2 glass-ceramics is characterized in that the particle size D of the CaO-B2O3-SiO2-CaF2 glass-ceramics is 50 0.5~3.0μm.

[0008] The method for preparing CaO-B2O3-SiO2-CaF2 glass-ceramics is characterized by comprising the following steps:

[0009] (1) Raw materials including 40-50 mol% of CaO, 3-18 mol% of B2O3, 35-45 mol% of SiO2, and 5-18 mol% of CaF2 are weighed and mixed using ethanol as a solvent, subjected to ball milling, filtered, dried, and sieved to obtain raw material powder, which is then melted at high temperature to obtain a glass melt, which is then quenched in water to obtain glass slag; preferably, the sieving is performed through a 100-mesh sieve.

[0010] (2) The glass slag obtained in step (1) was crushed by ball milling, ethanol was added to obtain a suspension, and then filtered, dried, and sieved to obtain a particle size D 50 The glass powder is CaO-B2O3-SiO2-CaF2 with a diameter of 0.5 to 3.0 μm; preferably, it is sieved through a 200-mesh sieve.

[0011] (3) Weigh the CaO-B2O3-SiO2-CaF2 glass powder obtained in the above step (2), add PVB solution, granulate, press, debind, and then sinter in an air atmosphere to obtain CaO-B2O3-SiO2-CaF2 microcrystalline glass.

[0012] The preparation method is characterized in that the ball milling mixture in step (1) includes zirconium balls, the mass ratio of the raw material: ethanol: zirconium balls is 1:1:3-6, and the ball milling time is 12 to 36 hours;

[0013] The diameter of the zirconium balls is preferably 5 to 15 mm, and the most preferred zirconium balls include small balls with a diameter of 5 mm, medium balls with a diameter of 10 mm, and large balls with a diameter of 15 mm, with the mass ratio of large balls: medium balls: small balls being 1:1:2-5.

[0014] The preparation method is characterized in that the drying conditions in step (1) are: drying temperature 80-120°C, drying time 12-36h, and the high-temperature smelting conditions are: smelting temperature 1400-1600°C, smelting time 0.5-2h.

[0015] The preparation method is characterized in that the drying conditions in step (2) are: drying temperature 80-120° C., and drying time 12-36 hours.

[0016] The preparation method is characterized in that the weight percentage of the PVB solution in step (3) is 4 to 6 wt.%, and the added mass of the PVB solution is the same as the mass of the CaO-B2O3-SiO2-CaF2 glass powder.

[0017] The preparation method is characterized in that the sintering conditions in step (3) are: sintering temperature 800-950°C, sintering time 10-120 minutes.

[0018] The CaO-B2O3-SiO2-CaF2 microcrystalline glass is used as a microcrystalline glass material with a low softening point and a high degree of densification.

[0019] The application of the CaO-B2O3-SiO2-CaF2 glass-ceramics in electronic device packaging.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention adds CaF2 raw material as Si-O network structure modifier, which greatly reduces the softening point of CaO-B2O3-SiO2 glass, broadens the glass sintering window and thus improves the compatibility of glass and electrode co-firing. At the same time, Ca in CaF2 2+ Two crystals, CaSiO3 and CaB2O4, can be formed together with the Si-O network and the BO network during the sintering process, thereby not destroying the microwave dielectric properties of the CaO-B2O3-SiO2 glass.

[0022] 2. The present invention utilizes a selective glass powder particle size to produce a highly densified CaO-B2O3-SiO2-CaF2 glass-ceramic after sintering. This CaO-B2O3-SiO2-CaF2 glass-ceramic exhibits a low softening point, a wide sintering window, high densification, and excellent microwave dielectric properties. Compared to existing CaO-B2O3-SiO2 glass, the glass-ceramic designed in the present invention has a lower softening point, a wider sintering window, and better compatibility with electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1It is the degree of internal densification of CaO-B2O3-SiO2-CaF2 glass-ceramics. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the accompanying drawings and examples.

[0025] Example 1: Preparation of CaO-B2O3-SiO2-CaF2 glass-ceramics

[0026] Step 1: Weigh the glass raw materials according to the mass ratio: CaO 44 mol%, B2O3 4 mol%, SiO2 44 mol%, and CaF2 8 mol%. The weighed raw materials were ball-milled for 24 hours using ethanol as the solvent, with the raw materials: ethanol: zirconium balls in a ratio of 1:1:4, with zirconium balls having a diameter of 5 mm. The mixed raw materials were filtered, dried at 100°C for 24 hours, and then passed through a 100-mesh sieve to obtain a raw material powder. The mixed raw material powder was then melted at 1500°C for 2 hours. The glass melt was quenched in distilled water to obtain glass slag.

[0027] Step 2: The glass slag prepared in step 1 was crushed by planetary ball milling, wherein the raw material: ethanol: zirconium ball = 1:1:4, the diameters of large, medium and small zirconium balls were 15mm, 10mm and 5mm respectively, and the ratio of large ball: medium ball: small ball = 1:1:3. The crushed glass powder was suspended in ethanol and filtered, then dried at 100℃ for 24h and passed through a 200 mesh sieve to obtain the average particle size (D 50 )2.0μm CaO-B2O3-SiO2-CaF2 glass powder.

[0028] Step 3: Take a certain amount of glass powder prepared in step 2 and add the same amount of 5wt.% PVB solution. Then granulate, press, debind and sinter in air at 850℃ for 10min to obtain CaO-B2O3-SiO2-CaF2 micro-ceramics with excellent performance. The internal densification degree of CaO-B2O3-SiO2-CaF2 micro-ceramics is as follows: Figure 1 As shown, the softening point is 680℃, the dielectric constant is 6.0, and the dielectric loss is 1.15×10 -3 .

[0029] Example 2:

[0030] The raw material contents in this embodiment are CaO 38 mol%, B2O3 16 mol%, SiO2 38 mol%, and CaF2 8 mol%. The glass preparation method is the same as that in the embodiment. The softening point of CaO-B2O3-SiO2-CaF2 glass-ceramics is 665°C, the dielectric constant is 6.5, and the dielectric loss is 2.10×10 -3 .

[0031] Example 3:

[0032] The raw material contents in this embodiment are 36 mol% CaO, 4 mol% B2O3, 44 mol% SiO2, and 16 mol% CaF2. The glass preparation method is the same as that in the embodiment. The softening point of CaO-B2O3-SiO2-CaF2 glass-ceramics is 670°C, the dielectric constant is 6.1, and the dielectric loss is 1.75×10 -3 .

[0033] Example 4:

[0034] The raw material components in this embodiment are CaO 48 mol%, B2O3 4 mol%, SiO2 40 mol%, and CaF2 8 mol%. The softening point of CaO-B2O3-SiO2-CaF2 glass-ceramics is 670°C, the dielectric constant is 6.1, and the dielectric loss is 1.05×10 -3 .

[0035] Example 5:

[0036] The raw material components in this embodiment are CaO 41 mol%, B2O3 16 mol%, SiO2 35 mol%, and CaF2 8 mol%. The softening point of CaO-B2O3-SiO2-CaF2 glass-ceramics is 655°C, the dielectric constant is 6.4, and the dielectric loss is 2.95×10 -3 .

[0037] Example 6:

[0038] The raw material components in this embodiment are CaO 40 mol%, B2O3 4 mol%, SiO2 40 mol%, and CaF2 16 mol%. The softening point of CaO-B2O3-SiO2-CaF2 glass-ceramics is 665°C, the dielectric constant is 6.0, and the dielectric loss is 1.15×10 -3 .

Claims

1. A CaO-B2O3-SiO2-CaF2 glass-ceramic for low-temperature co-fired ceramics, characterized in that The invention is composed of the following components in molar percentage: CaO 40-50 mol%, B2O3 3-18 mol%, SiO2 35-45 mol%, and CaF2 5-18 mol%. The particle size D of the CaO-B2O3-SiO2-CaF2 glass-ceramics 50 0.5~3.0μm.

2. The method for preparing CaO-B2O3-SiO2-CaF2 glass-ceramics for low-temperature co-fired ceramics according to claim 1, characterized in that The following steps are involved: (1) Weighing raw materials of CaO 40-50 mol%, B2O3 3-18 mol%, SiO2 35-45 mol%, and CaF2 5-18 mol%, ball-milling and mixing with ethanol as solvent, filtering, drying, and sieving to obtain raw material powder, high-temperature melting to obtain glass melt, and quenching in water to obtain glass slag; (2) The glass slag obtained in step (1) was crushed by ball milling, ethanol was added to obtain a suspension, and then filtered, dried, and sieved to obtain a particle size D 50 CaO-B2O3-SiO2-CaF2 glass powder of 0.5 to 3.0 μm; (3) Weigh the CaO-B2O3-SiO2-CaF2 glass powder obtained in the above step (2), add PVB solution, granulate, press, debind, and then sinter in an air atmosphere to obtain CaO-B2O3-SiO2-CaF2 microcrystalline glass.

3. A preparation method according to claim 2, characterized in that The composition of the ball milling mixture in step (1) includes zirconium balls, the mass ratio of the raw material: ethanol: zirconium balls is 1:1:3-6, and the ball milling mixing time is 12 to 36 hours.

4. A preparation method according to claim 3, characterized in that The diameter of the zirconium ball is 5 to 15 mm.

5. A preparation method according to claim 3, characterized in that The zirconium balls include small balls with a diameter of 5 mm, medium balls with a diameter of 10 mm, and large balls with a diameter of 15 mm. The mass ratio of large balls: medium balls: small balls is 1:1:2-5.

6. A preparation method according to claim 2, characterized in that The drying conditions in step (1) are: drying temperature 80-120° C., drying time 12-36 hours, and the high-temperature smelting conditions are: smelting temperature 1400-1600° C., smelting time 0.5-2 hours.

7. A preparation method according to claim 2, characterized in that The drying conditions in step (2) are: drying temperature 80-120° C., and drying time 12-36 hours.

8. A preparation method according to claim 2, characterized in that The weight percentage of the PVB solution in step (3) is 4 to 6 wt.%, and the added mass of the PVB solution is the same as the mass of the CaO-B2O3-SiO2-CaF2 glass powder.

9. A preparation method according to claim 2, characterized in that The sintering conditions in step (3) are: sintering temperature 800-950° C., and sintering time 10-120 min.

10. Use of the CaO-B2O3-SiO2-CaF2 glass-ceramics for low temperature co-fired ceramics as claimed in claim 1 as a glass-ceramics material with a low softening point and a high degree of densification.

11. Use of the CaO-B2O3-SiO2-CaF2 glass-ceramics for low temperature co-fired ceramics according to claim 1 in electronic device packaging.

Images