Low-expansion-coefficient glass powder for LTCC (Low Temperature Co-Fired Ceramic) and preparation method thereof

Abstract

The invention discloses low-expansion-coefficient glass powder for LTCC (low temperature co-fired ceramic) and a preparation method of the low-expansion-coefficient glass powder. The powder comprises the following raw materials in parts by weight: 20-45 parts of Al2O3, 40-65 parts of B2O3 and 2-10 parts of ZnO. According to the invention, a non-silicon-based glass substrate is adopted as a design basis, the ceramic powder has the characteristics of low melting temperature, low thermal expansion coefficient and low dielectric loss compared with pure ceramic powder, and compared with other ceramic powder, more glass powder is doped in the process, but the ceramic powder shows more excellent performance. The LTCC substrate prepared by mixing the ceramic powder and the glass powder can meet the requirements of more application scenes, and is a better choice for LTCC packaging materials. The problem that existing LTCC glass powder is incompatible in thermal expansion coefficient is solved.

Description

Technical Field

[0001] This invention relates to the field of electronic ceramic materials technology, specifically to a low coefficient of thermal expansion glass powder for LTCC and its preparation method. Background Technology

[0002] As IC chips move towards nanometer scale, the demands for smaller size, lighter weight, and higher reliability are increasing. Core components like integrated circuits face higher requirements in terms of chip size and packaging density. However, the thermal expansion coefficient of currently used LTCC (low-temperature co-fired ceramic) glass powder is generally quite large, limiting its thermal compatibility with other substrates.

[0003] Currently, there are many types of glass powders commonly used, but their coefficients of thermal expansion are relatively large, generally around 6.5, and their dielectric losses are also relatively high, some even reaching around 0.05. Currently, the substrate materials used for LTCC (Low-Temperature Ceramic Carbide) both domestically and internationally include ceramic series and microcrystalline glass series. The performance of ceramics is mainly determined by the ceramic phase, exhibiting characteristics such as stable performance, but their coefficient of thermal expansion is relatively large. Some ceramics are also composed of glass phase doping, which can reduce the coefficient of thermal expansion, but results in high dielectric losses. For example, LTCC materials composed of borosilicate lead glass and alumina ceramics can only be used below 8 GHz, limiting their application at high frequencies. The performance of microcrystalline glass is mainly determined by the type and quantity of precipitated crystalline phases. After sintering, almost no glass phase remains, thus exhibiting excellent dielectric properties at high frequencies. For example, calcium borosilicate microcrystalline glass can be used at frequencies up to 100 GHz. However, the crystallization conditions for microcrystalline glass have high requirements for the overall process flow, leading to poor product performance consistency. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a low coefficient of thermal expansion glass powder for LTCC and its preparation method, thereby resolving the issue of incompatibility in the thermal expansion coefficients of existing LTCC glass powders.

[0005] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A low-expansion-coefficient glass powder for LTCC is provided, comprising the following raw materials in parts by weight: 20-45 parts Al2O3, 40-65 parts B2O3, and 2-10 parts ZnO. Based on the above technical solution, the present invention can be further improved as follows: Furthermore, the glass powder for LTCC with low coefficient of thermal expansion comprises the following raw materials in parts by weight: 30 parts Al2O3, 50 parts B2O3, and 8 parts ZnO.

[0006] The present invention also provides a method for preparing the above-mentioned low coefficient of thermal expansion glass powder for LTCC, comprising the following steps: (1) Mix the raw materials evenly, grind them, sieve them, and then ball mill them to obtain ball mill material; (2) Dry the ball milling material obtained in step (1), grind it, then keep it at 1000-1300℃ for 3-6 hours, and then quench it to obtain glass slag; (3) The glass slag obtained in step (2) is ball-milled and dried to obtain glass powder for LTCC with low coefficient of expansion.

[0007] Furthermore, in step (1), a 10-30 mesh sieve is used for sieving.

[0008] Furthermore, in step (1), during ball milling, the mass ratio of raw material, agate ball and deionized water is 1:4:2-3.

[0009] Furthermore, in step (1), the ball milling is performed for 24-48 hours.

[0010] Furthermore, in step (1), a rolling ball mill is used.

[0011] Furthermore, in step (2), the product is dried at 90-105°C.

[0012] Furthermore, in step (2), quenching is performed in deionized water.

[0013] Furthermore, in step (3), a planetary ball mill is used for 8-10 hours.

[0014] Furthermore, in step (3), during ball milling, glass shavings, agate balls, and deionized water are mixed and ball milled.

[0015] Furthermore, in step (3), the product is dried at 90-105°C. The present invention also provides the application of the above-mentioned low coefficient of thermal expansion glass powder for LTCC in electronic packaging.

[0016] Furthermore, LTCC ceramic substrates will be prepared by mixing glass powder and ceramic powder used for LTCC with low coefficient of thermal expansion.

[0017] Furthermore, the ceramic powder is CaSiO3 ceramic powder, Zn2SiO4 ceramic powder, Mg2SiO4 ceramic powder, or Li2MgSiO4 ceramic powder.

[0018] Furthermore, the glass powder and ceramic powder used for LTCC with low coefficient of thermal expansion are mixed, ball-milled, binder is added, granulated, pressed into shape, and sintered to obtain LTCC ceramic substrate.

[0019] The present invention has the following beneficial effects: 1. In this invention, the thermal expansion coefficient and dielectric properties of the Al-B-Zn glass system depend on the glass network structure and the bridging oxygen ratio. In this invention, B serves as the glass network framework, Al acts as the network intermediate and forming agent, and Zn acts as the network modifier. Excess Al leads to a network framework structure dominated by aluminum-oxygen tetrahedra. Appropriate amounts of Zn hinder ion migration, fill network vacancies, and form a stable network structure. In this invention, the thermal expansion coefficient is 3.5-3.9 ppm / ℃, the dielectric constant is 5.1-6.4, and the dielectric loss is 1-10 × 10⁻⁶. -3 (1MHz~1GHz). Adding alkaline earth metals can effectively reduce glass porosity, stabilize the glass network structure, reduce dielectric loss under alternating electric fields, and simultaneously lower its coefficient of thermal expansion. This invention combines glass powder and ceramic powder to prepare LTCC powder with low coefficient of thermal expansion and low dielectric properties. Its process is simple, stable, and low-cost, making it suitable for mass production and of industrial significance.

[0020] 2. This invention uses a non-silicon-based glass substrate as its design basis, which features a low melting temperature and, compared to pure ceramic powder, a low coefficient of thermal expansion and low dielectric loss. Although it involves the addition of glass powder in the manufacturing process compared to other ceramic powders, it exhibits superior performance. LTCC substrates prepared by mixing ceramic and glass powders can meet the needs of more application scenarios and are a superior choice for LTCC packaging materials. Attached Figure Description

[0021] Figure 1 The dielectric constant of the products obtained from the powders in Examples 1-5; Figure 2 The dielectric loss of the products prepared from the powders in Examples 1-5 is shown. Detailed Implementation

[0022] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0023] Example 1: A glass powder for low coefficient of thermal expansion in LTCC comprises the following raw materials in parts by weight: 30 parts Al2O3, 50 parts B2O3, and 8 parts ZnO.

[0024] A method for preparing low coefficient of thermal expansion glass powder for LTCC includes the following steps: (1) Mix the raw materials evenly, grind them, sieve them through a 20-mesh sieve, and then ball mill them. When ball milling, the mass ratio of raw materials, agate balls and deionized water is 1:4:2.5. Put them into a nylon ball milling jar and ball mill them for 30 hours to obtain ball milling material. (2) The ball milling material obtained in step (1) is dried at 100°C, ground, placed in a crucible, placed in a melting furnace for melting, then kept at 1200°C for 5 hours, and then quenched in deionized water to obtain glass slag. (3) The glass slag, agate balls and deionized water obtained in step (2) are mixed and subjected to planetary ball milling for 9 hours, and then dried at 100°C to obtain glass powder for LTCC with low expansion coefficient.

[0025] Example 2: A glass powder for low coefficient of thermal expansion in LTCC comprises the following raw materials in parts by weight: 31 parts Al2O3, 51 parts B2O3, and 7 parts ZnO.

[0026] A method for preparing low coefficient of thermal expansion glass powder for LTCC includes the following steps: (1) Mix the raw materials evenly, grind them, sieve them through a 21-mesh sieve, and then ball mill them. During ball milling, the mass ratio of raw materials, agate balls and deionized water is 1:4:2.6. Put them into a nylon ball milling jar and use a rolling ball milling method for 31 hours to obtain ball milling material. (2) The ball milling material obtained in step (1) is dried at 101°C, ground, placed in a crucible, placed in a melting furnace for melting, then kept at 1250°C for 4.5h, and then quenched in deionized water to obtain glass slag. (3) The glass slag, agate balls and deionized water obtained in step (2) are mixed and subjected to planetary ball milling for 9.5 hours and dried at 101°C to obtain glass powder for LTCC with low expansion coefficient.

[0027] Example 3: A glass powder for low coefficient of thermal expansion in LTCC comprises the following raw materials in parts by weight: 32 parts Al2O3, 52 parts B2O3, and 9 parts ZnO.

[0028] A method for preparing low coefficient of thermal expansion glass powder for LTCC includes the following steps: (1) Mix the raw materials evenly, grind them, sieve them through a 22-mesh sieve, and then ball mill them. During ball milling, the mass ratio of raw materials, agate balls and deionized water is 1:4:2.7. Put them into a nylon ball milling jar and use a rolling ball milling method for 32 hours to obtain ball milling material. (2) The ball milling material obtained in step (1) is dried at 102°C, ground, placed in a crucible, placed in a melting furnace for melting, then kept at 1280°C for 4 hours, and then quenched in deionized water to obtain glass slag. (3) The glass slag, agate balls and deionized water obtained in step (2) are mixed and subjected to planetary ball milling for 9.6 hours and dried at 102°C to obtain glass powder for LTCC with low expansion coefficient.

[0029] Example 4: A glass powder for low coefficient of thermal expansion (LTCC) comprises the following raw materials in parts by weight: 20 parts Al2O3, 40 parts B2O3, and 2 parts ZnO.

[0030] A method for preparing low coefficient of thermal expansion glass powder for LTCC includes the following steps: (1) Mix the raw materials evenly, grind them, sieve them through a 10-mesh sieve, and then ball mill them. When ball milling, the mass ratio of raw materials, agate balls and deionized water is 1:4:2. Put them into a nylon ball milling jar and use a rolling ball milling method for 24 hours to obtain ball milling material. (2) The ball milling material obtained in step (1) is dried at 90°C, ground, placed in a crucible, placed in a melting furnace for melting, then kept at 1000°C for 6 hours, and then quenched in deionized water to obtain glass slag. (3) The glass slag, agate balls and deionized water obtained in step (2) are mixed and subjected to planetary ball milling for 8 hours, and then dried at 90°C to obtain glass powder for LTCC with low expansion coefficient.

[0031] Example 5: A glass powder for low coefficient of thermal expansion (LTCC) comprises the following raw materials in parts by weight: 45 parts Al2O3, 65 parts B2O3, and 10 parts ZnO.

[0032] A method for preparing low coefficient of thermal expansion glass powder for LTCC includes the following steps: (1) Mix the raw materials evenly, grind them, sieve them through a 30-mesh sieve, and then ball mill them. During ball milling, the mass ratio of raw materials, agate balls and deionized water is 1:4:3. Put them into a nylon ball milling jar and use a rolling ball milling method for 48 hours to obtain ball milling material. (2) The ball milling material obtained in step (1) is dried at 105°C, ground, placed in a crucible, placed in a melting furnace for melting, then kept at 1300°C for 3 hours, and then quenched in deionized water to obtain glass slag. (3) The glass slag, agate balls and deionized water obtained in step (2) are mixed and subjected to planetary ball milling for 10 hours, and then dried at 105°C to obtain glass powder for LTCC with low expansion coefficient.

[0033] Test case To test the performance of the glass powder for low coefficient of thermal expansion in LTCC, the glass powders for low coefficient of thermal expansion obtained in Examples 1-5 were prepared into samples according to the following method, and their performance was tested by a dielectric spectrum analyzer.

[0034] A low-temperature co-fired ceramic, the preparation method of which includes the following steps: S1: Mix glass powder and ceramic powder (CaSiO3 ceramic powder) for LTCC low expansion coefficient, and ball mill them. During ball milling, the mass ratio of powder, agate balls and deionized water is 1:5:2.5. Dry at 100℃, grind, and sieve through a 50-mesh sieve to obtain powder. S2: Add binder (50wt% acrylic acid aqueous solution) to the powder, granulate, place under a hydraulic press, and press into shape with a size of 50×4×3mm to obtain a sample; S3: Place the sample in a sintering furnace and pre-fire at 450℃ for 1 hour, then raise the temperature to 800℃ at a rate of 3℃ / min and hold for 1 hour to finally obtain a sample with a smooth surface.

[0035] See results Figure 1-2 See Table 1.

[0036] Table 1 Sintering Performance Table

[0037] Depend on Figure 1-2 As shown in Table 1, the low-temperature co-fired ceramic prepared from the low-expansion coefficient glass powder of LTCC invented in this invention has low dielectric properties and low thermal expansion coefficient, and can be applied to LTCC ceramic substrates.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-expansion-coefficient glass powder for LTCC, characterized in that, The raw materials include the following parts by weight: 20-45 parts Al2O3, 40-65 parts B2O3 and 2-10 parts ZnO.

2. The glass powder for low expansion coefficient LTCC according to claim 1, characterized in that, The raw materials include the following parts by weight: 30 parts Al2O3, 50 parts B2O3 and 8 parts ZnO.

3. The method for preparing low expansion coefficient glass powder for LTCC according to claim 1 or 2, characterized in that, Includes the following steps: (1) Mix the raw materials evenly, grind them, sieve them, and then ball mill them to obtain ball mill material; (2) Dry the ball milling material obtained in step (1), grind it, then keep it at 1000-1300℃ for 3-6 hours, and then quench it to obtain glass slag; (3) The glass slag obtained in step (2) is ball-milled and dried to obtain glass powder for LTCC with low coefficient of expansion.

4. The method for preparing low expansion coefficient glass powder for LTCC according to claim 3, characterized in that, In step (1), a 10-30 mesh sieve is used for sieving.

5. The method for preparing low expansion coefficient glass powder for LTCC according to claim 3, characterized in that, In step (1), during ball milling, the mass ratio of raw material, agate ball and deionized water is 1:4:2-3.

6. The method for preparing low expansion coefficient glass powder for LTCC according to claim 3, characterized in that, In step (2), the product is dried at 90-105℃.

7. The method for preparing low expansion coefficient glass powder for LTCC according to claim 3, characterized in that, In step (3), a planetary ball mill is used for 8-10 hours.

8. The method for preparing low expansion coefficient glass powder for LTCC according to claim 3, characterized in that, In step (3), during ball milling, glass shavings, agate balls and deionized water are mixed and ball milled.

9. The method for preparing low expansion coefficient glass powder for LTCC according to claim 3, characterized in that, In step (3), the product is dried at 90-105℃.

10. The application of the low coefficient of thermal expansion glass powder for LTCC in electronic packaging as described in any one of claims 1-2.

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