A medium thermal expansion glass-free phase low temperature co-fired ceramic packaging material and a preparation method thereof

Abstract

This invention relates to the field of ceramic encapsulation materials technology, and proposes a medium-thermal-expansion, glass-phase-free, low-temperature co-fired ceramic encapsulation material and its preparation method. The chemical formula of the ceramic encapsulation material is (Ca... a A 1‑a (Si) b B 1‑b (O) x F y The composition is as follows: A includes one or more of Li, Na, K, Sr, and Ba; B includes one or more of Mn, Fe, Zn, Co, Zr, Nb, Mo, and W; a, b, x, and y are molar ratios, where 0.2 ≤ a ≤ 0.95, 0.05 ≤ b ≤ 0.8, 1.25 ≤ x ≤ 3.3, and 0 ≤ y ≤ 0.8. This technical solution effectively solves the problem of mismatched thermal expansion coefficients between the chip and the printed circuit board in packaging technology.

Description

Technical Field

[0001] This invention relates to the field of ceramic packaging materials technology, specifically, to a medium-thermal-expansion glassless low-temperature co-fired ceramic packaging material and its preparation method. Background Technology

[0002] As electronic systems and devices evolve towards higher integration and higher power density, packaging reliability has become a critical factor affecting their performance and lifespan. The packaging substrate, acting as a bridge between the chip and external circuitry, not only needs to support the chip and facilitate electrical interconnection and signal transmission, but also needs to be effectively connected to the printed circuit board beneath it to ensure the stable operation of the entire electronic system. Failure at the packaging interface can directly lead to circuit interruptions, device failures, or even complete system paralysis. Therefore, packaging reliability is crucial for ensuring the stable operation of high-end electronic systems and devices.

[0003] However, in practical applications, the significant differences in the coefficients of thermal expansion of different materials can easily lead to thermal mismatch issues. For example, silicon chips have a relatively low coefficient of thermal expansion, approximately 4 ppm / ℃, while commonly used printed circuit board substrates such as FR-4 have a higher coefficient of thermal expansion, typically greater than 11 ppm / ℃. When devices experience power-on, heat dissipation, and changes in ambient temperature during operation, if the difference in the coefficients of thermal expansion between the packaging substrate and the chip or the underlying printed circuit board is too large, significant thermal stress will be generated at the interface, leading to substrate warping, cracking, or even interlayer delamination, severely affecting the reliability and lifespan of the device. Therefore, inserting a transition substrate made of a material with a medium coefficient of thermal expansion between the chip and the printed circuit board will greatly improve the overall reliability and stability of the package.

[0004] Most widely used low-temperature co-fired ceramic substrate materials are low-expansion or high-expansion systems, making it difficult to simultaneously match the thermal expansion requirements of chips and printed circuit boards. For example, while low-expansion low-expansion low-temperature co-fired ceramic materials can match chips well, they exhibit significant mismatch with printed circuit boards; conversely, high-expansion low-expansion low-temperature co-fired ceramic materials can fit printed circuit boards but are prone to generating thermal stress at the chip interface. This contradiction restricts the further application of low-temperature co-fired ceramics in high-density, high-reliability electronic packaging. Moreover, existing medium-thermal-expansion low-temperature co-fired ceramic packaging materials, due to the presence of a glass phase, lead to an increase in dielectric constant and dielectric loss. This is mainly because the glass phase typically contains polar components such as alkali metal or alkaline earth metal ions, whose internal dipoles are prone to polarization under an electric field. Furthermore, the poor uniformity of the glass phase structure and the presence of trace impurities or defects exacerbate energy loss during polarization relaxation, leading to an increase in the material's dielectric constant and dielectric loss, which in turn affects the electronic signal transmission rate and increases signal crosstalk.

[0005] Therefore, developing glassless low-temperature co-fired ceramic materials with a medium coefficient of thermal expansion has become an urgent problem to be solved. Summary of the Invention

[0006] This invention proposes a low-temperature co-fired ceramic packaging material with medium thermal expansion and no glass phase, and its preparation method, which solves the problem of mismatch in the coefficients of thermal expansion between the chip and the printed circuit board in related technologies.

[0007] The technical solution of the present invention is as follows: This invention proposes a low-temperature co-fired ceramic encapsulation material with medium thermal expansion and no glass phase. The chemical formula of the ceramic encapsulation material is (Ca... a A 1-a (Si) b B 1-b (O) x F y ), wherein A includes one or more of Li, Na, K, Sr and Ba, and B includes one or more of Mn, Fe, Zn, Co, Zr, Nb, Mo and W; a, b, x, y are molar ratios, 0.2≤a≤0.95, 0.05≤b≤0.8, 1.25≤x≤3.3, 0≤y≤0.8.

[0008] As a further technical solution, the coefficient of thermal expansion of the medium-thermal-expansion glassless low-temperature co-fired ceramic encapsulation material is 5.3~9.2ppm / ℃.

[0009] As a further technical solution, A and B are each introduced independently through metal oxides, fluorides, or carbonates.

[0010] This invention also proposes a method for preparing a medium-thermal-expansion, glass-phase-free, low-temperature co-fired ceramic encapsulation material, which includes the following steps: S1, according to (Ca) a A 1-a (Si) b B 1-b (O) x F y Weigh each raw material according to the molar ratio of ), mix them, perform wet ball milling, and then dry to obtain premixed powder; S2. The premixed powder is pre-calcined to obtain pre-calcined powder; S3. The pre-calcined powder is ground, granulated, and sieved to obtain powder; S4. Press the powder into shape and sinter it to obtain a ceramic encapsulation material.

[0011] As a further technical solution, the raw materials for introducing A include one or more of LiF, NaF, KF, SrO, and BaO.

[0012] As a further technical solution, the raw materials introduced into B include one or more of MnO2, Fe2O3, ZnO, Co2O3, ZrO2, Nb2O5, MoO3, and WO3.

[0013] As a further technical solution, the media used in the wet ball milling process are zirconium dioxide balls and anhydrous ethanol, the rotation speed is 350~450 r / min, and the time is 5~8 h.

[0014] As a further technical solution, the pre-firing temperature is 600~950℃, the holding time is 2~6h, and the heating rate is 4~6℃ / min.

[0015] As a further technical solution, the binder used in the granulation is a polyvinyl alcohol solution.

[0016] As a further technical solution, the polyvinyl alcohol solution is a 4wt%~6wt% aqueous solution of polyvinyl alcohol.

[0017] As a further technical solution, the pressure of the compression molding is 80~100MPa.

[0018] As a further technical solution, the sintering temperature is 500~950℃, and the holding time is 2~6h.

[0019] As a further technical solution, the sintering consists of a first sintering stage and a second sintering stage; The sintering temperature of the first stage is 500~700℃, the sintering time is 1~2h, and the heating rate is 1~2℃ / min; The second sintering temperature is 850~950℃, the sintering time is 2~4h, and the heating rate is 4~6℃ / min.

[0020] This invention improves the performance of ceramic encapsulation materials by employing a two-stage sintering method. The first stage of sintering uses a relatively low temperature of 500-700℃ and a slow heating rate of 1-2℃ / min, which gently and thoroughly removes residual moisture, organic binders (polyvinyl alcohol), and small amounts of impurities from the powder. This avoids the formation of defects such as pores and cracks inside the green body caused by the violent decomposition of the binder due to rapid heating, which would generate a large amount of gas. At the same time, it lays a uniform and dense green body foundation for subsequent high-temperature sintering. The second stage of sintering raises the temperature to a higher temperature of 850-950℃ at a rate of 4-6℃ / min and holds it at that temperature. This effectively promotes the uniform growth and densification of grains, further eliminates micropores inside the green body, improves the density and structural integrity of the ceramic material, and ensures the stable molding of the glass-free system. This gives the ceramic encapsulation material superior density, dielectric properties, and stability of the coefficient of thermal expansion.

[0021] The working principle and beneficial effects of this invention are as follows: This invention provides a medium-thermal-expansion, glass-phase-free, low-temperature co-fired ceramic encapsulation material, prepared by means of a chemical formula (Ca... a A 1-a (Si) b B 1-b (O) x F y A ceramic encapsulation material with a moderate coefficient of thermal expansion in the range of 5.3–9.2 ppm / ℃ was obtained by adjusting the types of elements A and B and the values ​​of a, b, x, and y. Element A was selected from one or more of Li, Na, K, Sr, and Ba. By using these alkali metals or alkaline earth metals to form solid solutions with Ca, the degree of lattice distortion could be controlled by the difference in ionic radii, thereby adjusting the thermal expansion characteristics of the ceramic encapsulation material. Element B was selected from one or more of Mn, Fe, Zn, Co, Zr, Nb, Mo, and W. By forming solid solutions with Si using transition metals or high-melting-point metals, the ceramic phase composition could be controlled, optimizing the stability of the crystal structure and the thermal expansion coordination. By controlling the concentrations of 0.2 ≤ a ≤ 0.95 and 0.05 ≤ b ≤ 0.8, precise control of the solid solution levels in the Ca-A and Si-B systems can be achieved. Combined with an oxygen content of 1.25 ≤ x ≤ 3.3, the integrity of the crystal structure is ensured. Fluorine substitution of 0 ≤ y ≤ 0.8 allows for further fine-tuning of thermal expansion characteristics by adjusting the lattice bond strength. This enables the entire ceramic packaging material to establish an effective thermal expansion gradient regulation system between the chip and the printed circuit board, avoiding the thermal mismatch problem caused by excessively high or low coefficients of thermal expansion in existing low-temperature co-fired ceramic materials. Furthermore, this invention employs a glass-phase-free design, preventing the precipitation and migration of the glass phase, thereby reducing dielectric loss and dielectric constant, and ensuring the stability of the ceramic packaging material under high-frequency and service conditions. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] In the following examples and comparative examples: Polyvinyl alcohol, model number: 2488.

[0024] Example 1 The chemical formula of a medium-thermal-expansion, glass-phase-free, low-temperature co-fired ceramic encapsulation material is Ca. 0.2 Li 0.8 Si 0.05 Mn 0.95O 1.25 F 0.8 ; A method for preparing a low-temperature co-fired ceramic encapsulation material with medium thermal expansion and no glass phase includes the following steps: S1. Weigh CaO, LiF, SiO2, and MnO2 powders according to the molar ratio to obtain raw materials. Add anhydrous ethanol and zirconium dioxide balls (the mass ratio of raw materials, anhydrous ethanol, and zirconium dioxide balls is 1:2:5). Ball mill at 350 r / min for 8 hours and then dry at 80℃ for 8 hours to obtain premixed powder. S2. The premixed powder is heated to 600℃ at 4℃ / min and held for 2h to obtain pre-calcined powder; S3. Add the pre-calcined powder to anhydrous ethanol (the mass ratio of anhydrous ethanol to pre-calcined powder is 2:1), grind for 5 hours at a speed of 300 r / min, dry, crush to 100 mesh, then add 5 wt% polyvinyl alcohol aqueous solution as a binder (the amount of polyvinyl alcohol aqueous solution added is 3 wt% of the pre-calcined powder), mix evenly, granulate, and pass through a 40 mesh sieve to obtain powder. S4. Press the powder into a circular green sheet at 80MPa, sinter it at 850℃ for 4h by heating at 4℃ / min, and then cool it with the furnace to obtain a low-temperature co-fired ceramic encapsulation material with medium thermal expansion and no glass phase.

[0025] Example 2 The chemical formula of a medium-thermal-expansion, glass-phase-free, low-temperature co-fired ceramic encapsulation material is Ca. 0.6 Li 0.4 Si 0.4 Mn 0.6 O2F 0.4 ; A method for preparing a low-temperature co-fired ceramic encapsulation material with medium thermal expansion and no glass phase includes the following steps: S1. Weigh CaO, LiF, SiO2, and MnO2 powders according to the molar ratio to obtain raw materials. Add anhydrous ethanol and zirconium dioxide balls (the total mass of raw materials and the mass ratio of anhydrous ethanol to zirconium dioxide balls are 1:2:5). Ball mill at 400 r / min for 6 hours and then dry at 80℃ for 9 hours to obtain premixed powder. S2. The premixed powder is heated to 750℃ at a rate of 5℃ / min and pre-calcined for 4 hours to obtain pre-calcined powder. S3. The pre-calcined powder is added to anhydrous ethanol (the mass ratio of anhydrous ethanol to pre-calcined powder is 2:1), ground for 5 hours at a speed of 300 r / min, dried, crushed to 100 mesh, and then 5 wt% polyvinyl alcohol aqueous solution is added as a binder (the amount of polyvinyl alcohol aqueous solution added is 3 wt% of the pre-calcined powder). After mixing evenly, it is granulated and passed through a 40 mesh sieve to obtain powder. S4. Press the powder into a circular green blank at 90 MPa, sinter it at 900℃ for 3 hours at a rate of 5℃ / min, and then cool it in the furnace to obtain a low-temperature co-fired ceramic encapsulation material with medium thermal expansion and no glass phase.

[0026] Example 3 The chemical formula of a medium-thermal-expansion, glass-phase-free, low-temperature co-fired ceramic encapsulation material is Ca. 0.95 Li 0.05 Si 0.8 Mn 0.2 O 2.75 F 0.05 ; A method for preparing a low-temperature co-fired ceramic encapsulation material with medium thermal expansion and no glass phase includes the following steps: S1. Weigh CaO, LiF, SiO2, and MnO2 powders according to the molar ratio to obtain raw materials. Add anhydrous ethanol and zirconium dioxide balls (the total mass of raw materials and the mass ratio of anhydrous ethanol to zirconium dioxide balls are 1:2:5). Ball mill at 450 r / min for 5 h, and then dry at 80℃ for 10 h to obtain premixed powder. S2. The premixed powder is heated to 950℃ at a rate of 6℃ / min and pre-calcined for 6 hours to obtain pre-calcined powder. S3. Add the pre-calcined powder to anhydrous ethanol (the mass ratio of anhydrous ethanol to pre-calcined powder is 2:1), grind for 5 hours at a speed of 300 r / min, dry, crush to 100 mesh, then add 5 wt% polyvinyl alcohol aqueous solution as a binder (the amount of polyvinyl alcohol aqueous solution added is 3 wt% of the pre-calcined powder), mix evenly, granulate, and pass through a 40 mesh sieve to obtain powder. S4. Press the powder into a circular green sheet at 100MPa, sinter it at 950℃ for 2 hours at a rate of 6℃ / min, and then cool it in the furnace to obtain a low-temperature co-fired ceramic encapsulation material with medium thermal expansion and no glass phase.

[0027] Example 4 The only difference between this embodiment and Embodiment 2 is that the chemical formula of the thermally expanding glassless low-temperature co-fired ceramic encapsulation material in this embodiment is Ca. 0.6 Na 0.4 Si 0.4 Mn 0.6 O2F 0.4 ; In the preparation method of medium thermal expansion glassless low-temperature co-fired ceramic encapsulation material, CaO, NaF, SiO2, and MnO2 powders are weighed in molar ratio.

[0028] Example 5 The only difference between this embodiment and Embodiment 2 is that the chemical formula of the thermally expanding glassless low-temperature co-fired ceramic encapsulation material in this embodiment is Ca. 0.3 K 0.6 Sr 0.4 Si 0.4 Nb 0.6 O3F 0.6 ; In the preparation method of medium thermal expansion glassless low-temperature co-fired ceramic encapsulation material, CaO, KF, SrO, SiO2, and Nb2O5 powders are weighed in molar ratio.

[0029] Example 6 The only difference between this embodiment and Embodiment 2 is that the chemical formula of the thermally expanding glassless low-temperature co-fired ceramic encapsulation material in this embodiment is Ca. 0.6 K 0.4 Si 0.4 Fe 0.6 O 2.3 F 0.4 ; In the preparation method of medium thermal expansion glassless low-temperature co-fired ceramic encapsulation material, CaO, KF, SiO2, and Fe2O3 powders are weighed in molar ratio.

[0030] Example 7 The only difference between this embodiment and Embodiment 2 is that the chemical formula of the thermally expanding glassless low-temperature co-fired ceramic encapsulation material in this embodiment is Ca. 0.8 Sr 0.2 Zr 0.1 Mo 0.3 Si 0.6 O 3.05 ; In the preparation method of medium thermal expansion non-glass phase low-temperature co-fired ceramic encapsulation material, CaO, SrO, ZrO2, MoO3, and SiO2 powders are weighed in molar ratio.

[0031] Example 8 The only difference between this embodiment and Embodiment 2 is that the chemical formula of the thermally expanding glassless low-temperature co-fired ceramic encapsulation material in this embodiment is Ca. 0.7 Sr 0.2 Ba 0.1 W 0.3 Si 0.7 O 3.05 ; In the preparation method of medium thermal expansion glassless low-temperature co-fired ceramic encapsulation material, CaO, SrO, BaO, WO3, and SiO2 powders are weighed in molar ratio.

[0032] Example 9 The only difference between this embodiment and Embodiment 2 is that in this embodiment, the powder is pressed into a circular green blank at 90 MPa, heated to 900°C at 4°C / min and sintered for 3 hours, and then cooled in the furnace to obtain a low-temperature co-fired ceramic encapsulation material with medium thermal expansion and no glass phase.

[0033] Example 10 The only difference between this embodiment and Embodiment 2 is that in this embodiment, the powder is pressed into a circular green blank at 90 MPa, heated to 900°C at 6°C / min and sintered for 3 hours, and then cooled in the furnace to obtain a low-temperature co-fired ceramic encapsulation material with medium thermal expansion and no glass phase.

[0034] Example 11 The only difference between this embodiment and Embodiment 2 is that in this embodiment, the powder is pressed into a circular green blank at 90 MPa, sintered at 600°C for 1 hour at a rate of 1°C / min, and then sintered at 900°C for 3 hours at a rate of 5°C / min. After cooling in the furnace, a low-temperature co-fired ceramic encapsulation material with medium thermal expansion and no glass phase is obtained.

[0035] Example 12 The only difference between this embodiment and Embodiment 2 is that in this embodiment, the powder is pressed into a circular green blank at 90 MPa, sintered at 600°C for 1 hour at a rate of 1.5°C / min, and then sintered at 900°C for 3 hours at a rate of 5°C / min. After cooling in the furnace, a low-temperature co-fired ceramic encapsulation material with medium thermal expansion and no glass phase is obtained.

[0036] Example 13 The only difference between this embodiment and Embodiment 2 is that in this embodiment, the powder is pressed into a circular green blank at 90 MPa, sintered at 600°C for 1 hour at a rate of 2°C / min, and then sintered at 900°C for 3 hours at a rate of 5°C / min. After cooling in the furnace, a low-temperature co-fired ceramic encapsulation material with medium thermal expansion and no glass phase is obtained.

[0037] Comparative Example 1 The only difference between this comparative example and Example 1 is that the chemical formula of the thermally expanding glassless low-temperature co-fired ceramic encapsulation material in this comparative example is Ca. 0.1 Li 0.9 Si 0.9 Mn 0.1 O2F 0.9 .

[0038] Comparative Example 2 The only difference between this comparative example and Example 1 is that the chemical formula of the thermally expanding glassless low-temperature co-fired ceramic encapsulation material in this comparative example is Ca. 0.98 Li 0.02 Si 0.03 Mn 0.97 O 2.01 F 0.02 .

[0039] Test case The ceramic encapsulation materials obtained in Examples 1-13 and Comparative Examples 1-2 were tested according to the following methods: 1. Coefficient of thermal expansion: According to GB / T 5594.3-2015 "Test methods for performance of structural ceramic materials for electronic components - Part 3: Test method for average linear expansion coefficient", the thermal expansion tester DIL 402Expedis Classic manufactured by NETZSCH GmbH, Germany was used for testing. During the test, the sample was prepared into a cylinder with a diameter of 6 mm and a length of 12 mm, and heated from room temperature to 400 °C at a heating rate of 5 °C / min. The change in sample length with temperature was obtained, and the linear expansion coefficient of the material was calculated accordingly. The test results are shown in Table 1 below. 2. Dielectric loss and relative permittivity: According to GB / T 43801-2024 "Test Method for Relative Permittivity and Loss Tangent of Copper Clad Laminates in Microwave Band - Split Dielectric Resonator Method", the split-pillar resonator (SPDR) method was used for testing at a frequency of 10 GHz. The resonant frequency and quality factor were measured using a PNA network analyzer (model E5227B) manufactured by Keysight Technologies, USA, and the relative permittivity (εr) and dielectric loss (tanδ) were calculated through the resonant parameters. The test sample was a circular wafer with a diameter of 22 mm and a thickness of 0.8 mm. The test results are shown in Tables 1 and 2 below.

[0040] Table 1 Performance test results of ceramic encapsulation materials prepared in Examples 1-8 and Comparative Examples 1-2

[0041] Compared with Comparative Examples 1-3, Examples 1-8 have lower dielectric losses than Comparative Examples 1-2. The coefficients of thermal expansion of the ceramic packaging materials prepared in Examples 1-8 are 5.3-9.2, indicating that adjusting the values ​​of a (0.2-0.95), b (0.05-0.8), x (1.25-3.3), and y (0-0.8) further optimizes the matching of the coefficients of thermal expansion between the chip and the printed circuit board and reduces dielectric losses.

[0042] Table 2 Performance test results of ceramic encapsulation materials prepared in Examples 2 and 9-13

[0043] The dielectric loss of Examples 11-13 is lower than that of Examples 2 and Examples 9-10, indicating that sintering at 600°C for 1 hour by first heating at 1-2°C / min and then sintering at 900°C for 3 hours by heating at 5°C / min can further reduce the dielectric loss of the ceramic encapsulation material.

[0044] The above are merely preferred embodiments of the present invention and are 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 medium-thermal-expansion, glass-phase-free, low-temperature co-fired ceramic encapsulation material, characterized in that, The chemical formula of the ceramic encapsulation material is (Ca a A 1-a (Si) b B 1-b (O) x F y ), wherein A includes one or more of Li, Na, K, Sr and Ba, and B includes one or more of Mn, Fe, Zn, Co, Zr, Nb, Mo and W; a, b, x, y are molar ratios, 0.2≤a≤0.95, 0.05≤b≤0.8, 1.25≤x≤3.3, 0≤y≤0.

8.

2. The medium-thermal-expansion glassless low-temperature co-fired ceramic encapsulation material according to claim 1, characterized in that, A and B are each introduced independently via metal oxides, fluorides, or carbonates.

3. A method for preparing a medium-thermal-expansion, glass-phase-free, low-temperature co-fired ceramic encapsulation material, used to prepare the ceramic encapsulation material according to any one of claims 1-2, characterized in that, Includes the following steps: S1, according to (Ca) a A 1-a (Si) b B 1-b (O) x F y Weigh each raw material according to the molar ratio of ), mix them, perform wet ball milling, and then dry to obtain premixed powder; S2. The premixed powder is pre-calcined to obtain pre-calcined powder; S3. The pre-calcined powder is ground, granulated, and sieved to obtain powder; S4. Press the powder into shape and sinter it to obtain a ceramic encapsulation material.

4. The method for preparing a medium-thermal-expansion glassless low-temperature co-fired ceramic encapsulation material according to claim 3, characterized in that, The raw materials introduced into A include one or more of LiF, NaF, KF, SrO, and BaO.

5. The method for preparing a medium-thermal-expansion glassless low-temperature co-fired ceramic encapsulation material according to claim 3, characterized in that, The raw materials introduced into B include one or more of MnO2, Fe2O3, ZnO, Co2O3, ZrO2, Nb2O5, MoO3, and WO3.

6. The method for preparing a medium-thermal-expansion glassless low-temperature co-fired ceramic encapsulation material according to claim 3, characterized in that, The wet ball milling medium is zirconium dioxide balls and anhydrous ethanol, the rotation speed is 350~450 r / min, and the time is 5~8 h.

7. The method for preparing a medium-thermal-expansion glassless low-temperature co-fired ceramic encapsulation material according to claim 3, characterized in that, The preheating temperature is 600~950℃, the holding time is 2~6h, and the heating rate is 4~6℃ / min.

8. The method for preparing a medium-thermal-expansion glassless low-temperature co-fired ceramic encapsulation material according to claim 3, characterized in that, The binder used in the granulation is a polyvinyl alcohol solution.

9. The method for preparing a medium-thermal-expansion glassless low-temperature co-fired ceramic encapsulation material according to claim 3, characterized in that, The sintering temperature is 500~950℃, and the holding time is 2~6h.

10. The method for preparing a medium-thermal-expansion glassless low-temperature co-fired ceramic encapsulation material according to claim 9, characterized in that, The sintering process consists of a first sintering stage and a second sintering stage. The sintering temperature of the first stage is 500~700℃, the sintering time is 1~2h, and the heating rate is 1~2℃ / min; The second sintering temperature is 850~950℃, the sintering time is 2~4h, and the heating rate is 4~6℃ / min.

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