Low-dielectric ternary-system low-sintering-temperature glass ceramic dielectric material and preparation method thereof

Abstract

The invention relates to the technical field of electronic ceramics, in particular to a low-dielectric ternary system low-sintering-temperature glass ceramic dielectric material and a preparation method thereof, the chemical formula of the low-dielectric ternary system low-sintering-temperature glass ceramic dielectric material is Li3AlxByO6 + delta, and the raw materials comprise Li2CO3, Al2O3 and B2O3. The main crystal phase of the glass ceramic dielectric material obtained by sintering is Li3AlB2O6, the secondary phase is LiAlB2O5, the glass ceramic dielectric material has a low dielectric constant and a low sintering temperature, the relative dielectric constant of the glass ceramic dielectric material at a test frequency (15GHz) is as low as 3-5, the temperature coefficient of resonance frequency is-79--121 ppm / DEG C, the quality factor can reach 21965-32497 GHz, and the sintering temperature is 850-850 DEG C. The problem that application of an existing dielectric material is limited due to high sintering temperature is solved.

Description

Technical Field

[0001] The invention relates to the technical field of electronic ceramics, and in particular to a low-dielectric ternary system low-sintering temperature glass ceramic dielectric material and a preparation method thereof. Background Art

[0002] 5G is the foundation for realizing the interconnection of all things. With the development of the Internet of Things, 5G has become the focus of people's attention. Generally, dielectric ceramic materials with practical application potential meet the following aspects, including small dielectric constant (ε r ), good quality factor (Q×f) and near-zero resonant frequency temperature coefficient (τ f ). In addition, the dielectric ceramic material should also have a low sintering temperature to meet the requirements of low temperature co-fired ceramic (LTCC) technology. Therefore, microwave dielectric ceramic materials with lower dielectric constant, good microwave dielectric properties and low sintering temperature are urgently needed by the current 5G communication technology and have important industrial value.

[0003] Low-temperature co-fired microwave dielectric ceramics have been extensively studied at home and abroad, mainly in three categories: ceramic system, microcrystalline glass system (also known as glass ceramic system) and glass + ceramic composite system. At present, low dielectric constant dielectric materials mainly include A12O3 system, SiO2 system, glass + ceramic, microcrystalline glass system, polymer ceramic and single-phase ceramic system. There are many systems of microwave dielectric ceramics, but most of them need to be sintered at a high temperature above 950°C. The main problem currently faced is the contradiction between high performance and low sintering temperature. Although some LTCC microwave dielectric ceramic systems have achieved low-temperature sintering, the addition of sintering aids has a negative impact on the dielectric properties to varying degrees. Microcrystalline glass material is a type of dielectric material formed by controlling the microcrystallization process in the glass matrix. Compared with traditional glass and ceramics, microcrystalline glass has the advantages of both, with both the processability and plasticity of glass and the mechanical strength and thermal stability of ceramics. More importantly, microcrystalline glass has shown great potential in both low dielectric constant and low sintering temperature. In existing research, low dielectric constant microcrystalline glass materials are mostly based on phosphate, borate and silicate systems. By introducing different oxides or non-oxides, such as fluorides, researchers can further reduce the dielectric constant of the material. For example, glass systems rich in B2O3-SiO2 have been widely used in the development of low dielectric materials. In response to the needs of millimeter wave technology in diverse applications, the core of microcrystalline glass material research lies in the optimization of material components, the regulation of phase composition and the control of processing technology to achieve specific application goals. At present, the commercial application of low dielectric constant microcrystalline glass is concentrated in microwave devices, antenna substrates, integrated circuits and packaging materials. The ε of most LTCC substrate materials on the market is less than 10%. r Only a few materials have an ε between 5 and 8. rThe value is lower than 5, and these materials are mainly designed for microwave low-frequency applications, and there is little research on their performance in the millimeter wave band. Therefore, in the face of the advent of the current 5G and 6G era, in order to meet the current 5G fields, especially the materials field, the ultra-low ε r The demand for the use of dielectric materials and the development of low-dielectric materials suitable for various application scenarios in the 5G frequency band can meet the current social needs and are of great significance. Summary of the invention

[0004] The purpose of the present invention is to provide a low-dielectric ternary system low-sintering temperature glass-ceramic dielectric material and a preparation method thereof, in order to solve the problem that the existing dielectric materials are limited in application due to the high sintering temperature.

[0005] To achieve the above objectives, in the first aspect, the present invention provides a low dielectric ternary system low sintering temperature glass ceramic dielectric material, wherein the raw material composition of the glass ceramic dielectric material includes Li2CO3, Al2O3 and B2O3, and the chemical formula is Li3Al x B y O 6+δ The main crystal phase of the sintered glass-ceramic dielectric material is Li3AlB2O6, and the secondary phase is LiAlB2O5.

[0006] Wherein, the range of x is 0.9-1.1, and the range of y is 3-5.

[0007] The melting temperature of the glass ceramic dielectric material is 900°C to 1200°C, the sintering temperature of the glass ceramic dielectric material is 635°C to 735°C, the dielectric constant is 3 to 5, and the frequency temperature coefficient is -79 to -121 ppm / °C.

[0008] In a second aspect, the present invention further provides a method for preparing a low-medium ternary system low-sintering temperature glass-ceramic dielectric material, which is applied to prepare the low-medium ternary system low-sintering temperature glass-ceramic dielectric material as described in the first aspect above, and is characterized in that it comprises the following steps:

[0009] Based on Li3Al x B y O 6+δ The raw materials Li2CO3, Al2O3 and B2O3 are batched according to the stoichiometric ratio in the chemical formula to obtain batched powder;

[0010] The ingredient powder is mixed with zirconium balls and alcohol for ball milling, and then dried and sieved to obtain sieved powder;

[0011] The sieved powder is sequentially melted, heat-insulated, water-quenched, dried and ground to prepare glass powder, and the glass powder is then mixed with zirconium balls and alcohol and ball-milled, dried and sieved to obtain glass powder;

[0012] A binder is added to the glass powder to form the glass powder, and the glass-ceramic dielectric material is prepared by sintering after debinding.

[0013] The ratio of the mixed powder, zirconium balls and alcohol for ball milling is 1:2:2, the ratio of the glass powder, zirconium balls and alcohol is 1:2:2, and the binder is 20% to 30% by mass of polymethyl methacrylate.

[0014] The low-medium ternary system low sintering temperature glass ceramic dielectric material of the present invention comprises raw materials including Li2CO3, Al2O3 and B2O3, and the chemical formula is Li3Al x B y O 6+δ , wherein x ranges from 0.9 to 1.1, y ranges from 3 to 5, the melting temperature is 900°C to 1200°C, the sintering temperature of the glass-ceramic dielectric material is 635°C to 735°C, the dielectric constant is 3 to 5, the frequency temperature coefficient is -79 to -121ppm / °C, the main crystalline phase of the sintered glass-ceramic dielectric material is Li3AlB2O6, and the secondary phase is LiAlB2O5. The glass-ceramic dielectric material is a glass-ceramic dielectric material with low dielectric constant and sintering temperature. Its relative dielectric constant at the test frequency (15GHz) is as low as 3 to 5, the resonant frequency temperature coefficient is -79 to -121ppm / °C, and the quality factor can reach 21965-32497GHz, which solves the problem that the existing dielectric materials are limited in application due to the high sintering temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is the embodiment of the present invention Li3Al x B y O 6+δ (x=0.9-1.1, y=4) XRD diffraction pattern of the material after being kept at the optimal sintering temperature for 4 hours.

[0017] Figure 2 It is the embodiment of the present invention Li3Al x B y O 6+δ (x=1, y=3-5) XRD diffraction pattern of the material after being kept at the optimal sintering temperature for 4 hours.

[0018] Figure 3 It is a flow chart of the method for preparing the low-dielectric ternary system low-sintering temperature glass-ceramic dielectric material provided by the present invention. DETAILED DESCRIPTION

[0019] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0020] In the first aspect, the present invention provides a low dielectric ternary system low sintering temperature glass ceramic dielectric material, the raw material composition of the glass ceramic dielectric material includes Li2CO3, Al2O3 and B2O3, the chemical formula is Li3Al x B y O 6+δ The main crystal phase of the sintered glass-ceramic dielectric material is Li3AlB2O6, and the secondary phase is LiAlB2O5.

[0021] In the embodiment of the present invention, Li2CO3, Al2O3 and B2O3 are included, and the chemical formula is Li3Al x B y O 6+δ , wherein x ranges from 0.9 to 1.1, y ranges from 3 to 5, the melting temperature is 900°C to 1200°C, the sintering temperature of the glass-ceramic dielectric material is 635°C to 735°C, the dielectric constant is 3 to 5, the resonant frequency temperature coefficient is -79 to -121ppm / °C, the main crystalline phase of the sintered glass-ceramic dielectric material is Li3AlB2O6, and the secondary phase is LiAlB2O5. The glass-ceramic dielectric material is a glass-ceramic dielectric material with low dielectric constant and sintering temperature. Its relative dielectric constant at the test frequency (15GHz) is as low as 3 to 5, the resonant frequency temperature coefficient is -79 to -121ppm / °C, and the quality factor can reach 21965-32497GHz, which solves the problem that the existing dielectric materials are limited in application due to the high sintering temperature.

[0022] See also Figures 1 to 3 In a second aspect, the present invention further provides a method for preparing a low-medium ternary system low-sintering temperature glass-ceramic dielectric material, which is applied to prepare the low-medium ternary system low-sintering temperature glass-ceramic dielectric material as described in the first aspect above, and is characterized in that it comprises the following steps:

[0023] S01 The raw materials Li2CO3, Al2O3 and B2O3 are batched according to the stoichiometric ratio based on the chemical formula to obtain batched powder;

[0024] In the embodiment of the present invention, the raw materials Li2CO3, Al2O3 and B2O3 are prepared according to the chemical formula Li3Al x B y O 6+δ , (x=0.9~1.1, y=3~5), the ingredients are mixed in a stoichiometric ratio to obtain a mixed powder.

[0025] S02: mixing the ingredient powder with zirconium balls and alcohol, ball milling, and then drying and sieving to obtain sieved powder;

[0026] In an embodiment of the present invention, the ingredient powder is mixed with zirconium balls and alcohol in a ratio of 1:2:2 in a ball mill for ball milling and planetary ball milling for 4 to 5 hours. The fully mixed powder after ball milling is dried in an oven at 90°C to 120°C, and then sieved with a 60-mesh sieve to obtain a sieved powder.

[0027] S03 sequentially melts, heats, water-quenches, dries, and grinds the sieved powder to prepare glass powder, and then mixes the glass powder with zirconium balls and alcohol, performs ball milling, dries, and sieves to obtain glass powder;

[0028] In an embodiment of the present invention, the sieved powder is kept warm at 900°C to 1200°C in an atmospheric atmosphere for 40min to 120min, the molten glass is quickly poured into deionized water, quenched and dried, the dried glass is ground again through a 60-120 mesh sieve, and ball milled with zirconium balls: alcohol in a mass ratio of 1:2:2, planetary ball milled for 5 to 10 hours, and the evenly mixed slurry is taken out and dried in an oven at 90°C to 120°C to obtain glass powder.

[0029] S04: adding a binder to the glass powder to press and shape the powder, and sintering the powder after debinding to prepare a glass ceramic dielectric material.

[0030] In an embodiment of the present invention, a binder is added to the glass powder and pressed into shape. After debinding at 450°C, the powder is sintered in air at 635°C to 735°C for 4 to 8 hours to produce a low-dielectric Li2O-Al2O3-B2O3 ternary system glass ceramic dielectric material.

[0031] The binder is 20% to 30% by mass of polymethyl methacrylate (PMMA).

[0032] Specific examples of the above preparation methods and materials Li3Al x B y O 6+δ (x=0.9~1.1,y=3~5) The composition and microwave dielectric properties of the material are as follows:

[0033]

[0034] The data in the above table include the proportions of the implementation parts, results and sample properties within the scope of the chemical formula. It can be seen from the table that the Li2O-Al2O3-B2O3 ternary system glass ceramics have excellent dielectric properties, low sintering temperature and low dielectric constant. Figure 1 and Figure 2 For the embodiment of the present invention, Li3Al x B y O 6+δ (x=0.9-1.1, y=3-5) XRD diffraction pattern of the material after being kept at the optimal sintering temperature for 4 hours. Figure 1 and Figure 2 It can be seen that the main crystal phase of Sample 1, Sample 2, Sample 3, Sample 4 and Sample 5 is Li3AlB2O6, and the secondary phase is LiAlB2O5.

[0035] The above disclosure is only a preferred embodiment of the low-dielectric ternary system low-sintering temperature glass-ceramic dielectric material and its preparation method of the present invention. Of course, this cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments are implemented, and equivalent changes made according to the claims of the present invention are still within the scope of the invention.

Claims

1. Low dielectric ternary system low sintering temperature glass ceramic dielectric material, characterized in that: The raw materials of the glass ceramic dielectric material include Li2CO3, Al2O3 and B2O3, and the chemical formula is Li3Al x B y O 6+δ The main crystalline phase of the sintered glass-ceramic dielectric material is Li3AlB2O6, and the secondary phase is LiAlB2O5.

2. The low dielectric ternary system low sintering temperature glass ceramic dielectric material according to claim 1, characterized in that: The x range is 0.9-1.1, and the y range is 3-5.

3. The low dielectric ternary system low sintering temperature glass ceramic dielectric material according to claim 1, characterized in that: The melting temperature of the glass ceramic dielectric material is 900° C. to 1200° C., the sintering temperature of the glass ceramic dielectric material is 635° C. to 735° C., the dielectric constant is 3 to 5, and the frequency temperature coefficient is -79 to -121 ppm / ° C.

4. A method for preparing a low-medium ternary system low-sintering temperature glass-ceramic dielectric material, which is applied to prepare a low-medium ternary system low-sintering temperature glass-ceramic dielectric material as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: Based on Li3Al x B y O 6+δ The raw materials Li2CO3, Al2O3 and B2O3 are batched according to the stoichiometric ratio in the chemical formula to obtain batched powder; The ingredient powder is mixed with zirconium balls and alcohol for ball milling, and then dried and sieved to obtain sieved powder; The sieved powder is sequentially melted, heat-insulated, water-quenched, dried and ground to prepare glass powder, and the glass powder is then mixed with zirconium balls and alcohol and ball-milled, dried and sieved to obtain glass powder; A binder is added to the glass powder to form the glass powder, and the glass-ceramic dielectric material is prepared by sintering after debinding.

5. The method for preparing the low-medium ternary system low sintering temperature glass-ceramic dielectric material according to claim 4, characterized in that: The mixing and ball-milling ratio of the batching powder, zirconium balls and alcohol is 1:2:2, the ratio of the glass powder, zirconium balls and alcohol is 1:2:2, and the binder is 20% to 30% by mass of polymethyl methacrylate.

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