Green ceramic chip, ceramic substrate and preparation method

Abstract

The invention discloses a green ceramic chip, a ceramic substrate and a preparation method, and relates to the technical field of electronic ceramics. According to the invention, the raw ceramic chip with a specific ratio is designed, the ceramic substrate containing multiple layers of raw ceramic chips is designed on the basis of the raw ceramic chip, and the ratio of the raw ceramic chip of each layer is controlled to enable the thermal expansion coefficient of each layer to meet gradient change, so that the problem that CTE of heterogeneous materials in system-level packaging is not matched is effectively solved; in addition, the green ceramic chip is higher in mechanical strength and heat conductivity coefficient, and the prepared ceramic substrate has higher impact resistance and can adapt to more application scenes.

Description

Technical Field

[0001] This invention relates to the field of electronic ceramics technology, and in particular to a green ceramic sheet, a ceramic substrate, and a method for preparing them. Background Technology

[0002] In the packaging field, we often face the challenge of packaging components and devices made of different materials, such as chips, solder balls, PCBs, ceramic boards, plastic components, and metal components. Heterogeneous packaging involves large differences in the CTE of different materials, which leads to an uneven ability of the entire packaging system to resist changes in ambient temperature or operating temperature during use. This causes thermal mismatch and results in defects such as cracking failure, deformation, short circuits, and desoldering. Summary of the Invention

[0003] The main objective of this invention is to develop an electronic ceramic substrate for packaging that can be matched with various application scenarios, effectively solve the thermal mismatch problem, and has strong thermal conductivity and high mechanical strength.

[0004] To achieve the above objectives, the present invention proposes a raw ceramic sheet, wherein the raw material of the raw ceramic sheet includes yttrium-stabilized zirconium oxide with a mass fraction of 5wt% to 25wt%; the weight ratio of yttrium oxide to zirconium oxide used to prepare the yttrium-stabilized zirconium oxide is 1:1 to 5.

[0005] In one embodiment, the raw material for the green ceramic tile further includes 65wt% to 85wt% alumina and / or aluminum nitride.

[0006] In one embodiment, the raw materials for the green ceramic sheet include: yttrium-stabilized zirconium oxide: 5wt%~25wt%; alumina: 65wt%~85wt%; calcium oxide: 5wt%; or, the raw materials for the green ceramic sheet include: yttrium-stabilized zirconium oxide: 5wt%~25wt%; aluminum nitride: 20wt%~85wt%; alumina: 0wt%~45wt%; calcium oxide: 5wt%.

[0007] In one embodiment, the method for preparing the yttrium-stabilized zirconium oxide includes the following steps: P1. Prepare the zirconium oxide and alumina powders according to the specified ratio, mix and wet grind, then dry, pulverize and sieve; P2. Sinter the powder processed in step P1, then pulverize, grind and sieve to complete the preparation of the yttrium-stabilized zirconium oxide.

[0008] The present invention also proposes a ceramic substrate comprising the above-mentioned green ceramic sheet; the ceramic substrate comprises multiple layers of the green ceramic sheet stacked sequentially, and the content of yttrium-stabilized zirconium oxide in the green ceramic sheet exhibits a gradient change along a direction perpendicular to the ceramic substrate.

[0009] In one embodiment, as the content of the yttrium-stabilized zirconium oxide in the green ceramic sheet increases, the amount of yttrium oxide used to prepare the yttrium-stabilized zirconium oxide decreases.

[0010] In one embodiment, the thickness of the ceramic substrate does not exceed 2 mm; and the thickness of each layer of the green ceramic sheet in the ceramic substrate is 0.1 mm to 0.4 mm.

[0011] The present invention also proposes a method for preparing the ceramic substrate, comprising the following steps: S1. Mix the raw materials according to the formula, add solvent and additives, and perform wet milling to prepare green ceramic slurry; S2. The green ceramic slurry is degassed, cast, cut into pieces and stacked, and then subjected to isostatic pressing to obtain a green body. S3. The green body obtained in step S3 is subjected to debinding, pre-firing and sintering in sequence to obtain a semi-finished product; S4. Anneal and post-process the semi-finished product to complete the preparation of the ceramic substrate.

[0012] In one embodiment, in step S2, the isostatic pressing treatment is performed at a pressure of 1000 Psi to 12000 Psi, a temperature of 40°C to 85°C, and a holding time of 2 min to 60 min. And / or, in step S3, the glue removal temperature is 200℃~650℃, the heating rate is 0.1℃ / min~2℃ / min, and the glue removal time is 4h~96h; And / or, in step S3, the pre-firing temperature is 750℃~1300℃, and the pre-firing time is 2h~48h; And / or, in step S3, the sintering temperature is 750℃~1800℃, the sintering time is 4h~48h, and the sintering pressure is 1Mpa~100Mpa; And / or, in step S4, the annealing temperature is 100℃~300℃ lower than the sintering temperature, and the annealing time is 1h~8h; And / or, in step S4, the post-processing includes cleaning, drying, coating, and etching.

[0013] The technical solution of this invention designs a green ceramic sheet using yttrium-stabilized zirconium oxide, alumina, aluminum nitride, and other ceramic powders as the main raw materials. Based on this green ceramic sheet, a ceramic substrate containing multiple layers of green ceramic sheets of the same type is designed. By controlling the raw material ratio of each layer of green ceramic sheet, the thermal expansion coefficient of each layer is made to meet the gradient change, so that the resulting ceramic substrate can effectively solve the problem of CTE mismatch between heterogeneous materials in system-in-package (SISP) to meet the needs of different application scenarios. In addition, the green ceramic sheet produced by this invention has higher mechanical strength and higher thermal conductivity, better resistance to extreme environmental impact, and can adapt to more special application scenarios, thus possessing high market value. Detailed Implementation

[0014] 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 a part of the embodiments of the present invention, and not all of the 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.

[0015] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0016] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0017] The technical problem solved by this application is that in the packaging field, there is often a combination of components and devices of different materials, such as chips, solder balls, PCB boards, ceramic boards, plastic components, and metal components. Heterogeneous packaging involves large differences in the CTE of different materials, which leads to an uneven ability of the entire packaging system to resist changes in ambient temperature or operating temperature during use, causing thermal mismatch and resulting in defects such as cracking failure, deformation, short circuit, and desoldering.

[0018] The raw materials used in the multilayer ceramic substrates in related technologies tend to be those corresponding to the LTCC system, which have low sintering temperatures and relatively low flexural strength. Another related technology mainly involves single-type CTE ceramics, which are simple to prepare, but suffer from a large difference in CTE compared to other devices or components, inevitably leading to thermal mismatch issues.

[0019] To address the aforementioned technical issues, this application designs multiple gradient-adjustable non-glass system multilayer co-fired ceramic substrate formulations.

[0020] This application proposes a green ceramic sheet comprising 5wt% to 25wt% yttrium-stabilized zirconium oxide; the weight ratio of yttrium oxide to zirconium oxide used to prepare the yttrium-stabilized zirconium oxide is 1:1 to 5.

[0021] It should be noted that this invention buffers the thermal mismatch problem between heterogeneous materials by constructing a multilayer ceramic substrate with a gradient coefficient of thermal expansion. Specifically, the green ceramic sheet achieves synergistic control of the material's CTE, mechanical strength, and thermal conductivity by controlling the content of yttrium-stabilized zirconium oxide to 5wt%~25wt% and adjusting the weight ratio of yttrium oxide to zirconium oxide in the yttrium-stabilized zirconium oxide.

[0022] Furthermore, in one embodiment, the raw material for the green ceramic tile also includes 65wt% to 85wt% alumina and / or aluminum nitride.

[0023] Specifically, yttrium-stabilized zirconia has a high CTE value, while alumina and aluminum nitride have relatively low CTEs. By adjusting the proportions of these components in each layer of green ceramic sheet in the ceramic substrate, a continuous gradient change in CTE can be achieved for each layer. This allows for the gradual absorption and dispersion of thermal stress between different packaging components during temperature changes, effectively suppressing failures such as cracking, deformation, and desoldering caused by CTE differences. Furthermore, the green ceramic sheet system of this invention uses yttrium-doped yttrium-stabilized zirconia. The higher yttrium content helps to obtain a more stable cubic phase structure, which is then combined with the highly thermally conductive aluminum nitride phase and the high-strength alumina phase. This enhances the overall mechanical strength and thermal conductivity, while also improving the substrate's thermal shock resistance and environmental adaptability.

[0024] In one embodiment, the raw materials for the green ceramic sheet include: yttrium-stabilized zirconium oxide: 5wt%~25wt%; alumina: 65wt%~85wt%; and calcium oxide: 5wt%.

[0025] It is understood that this embodiment uses alumina as the main component, and incorporates 5wt%~25wt% yttrium-stabilized zirconium oxide and 5wt% calcium oxide to form a composite ceramic system. Alumina provides the foundation for high strength, good insulation, and a moderate coefficient of thermal expansion; yttrium-stabilized zirconium oxide has a high CTE, approximately (10~11)×10⁻⁶. -6 / K, by changing its content, can continuously improve the overall CTE value of the composite layer within a certain range; at the same time, the phase stability characteristics of yttrium-stabilized zirconia itself are beneficial to enhancing the toughness and thermal shock resistance of the material. Calcium oxide mainly acts as a sintering aid. It can form a eutectic phase with alumina and other materials, significantly reducing the sintering temperature of the system, improving the densification process, and enabling green ceramic sheets to achieve high strength while maintaining a feasible process window.

[0026] In another embodiment, the raw materials for the green ceramic sheet include: yttrium-stabilized zirconium oxide: 5wt%~25wt%; aluminum nitride: 20wt%~85wt%; alumina: 0wt%~45wt%; and calcium oxide: 5wt%.

[0027] Specifically, aluminum nitride has high thermal conductivity but a low CTE value, only about 4.5 × 10⁻⁶. -6 / K; The high CTE of yttrium-stabilized zirconia can effectively neutralize the low CTE value of aluminum nitride introduced in large quantities; In this embodiment, by precisely setting the proportion of each powder in this embodiment, the thermal conductivity and CTE value of the single-layer green ceramic sheet are finely adjusted to achieve performance customization. Based on this, a gradient structure is obtained by stacking design, which achieves dual optimization: first, thermodynamic matching, the gradient CTE effectively buffers and eliminates thermal stress between heterogeneous materials; second, thermal management optimization, the high thermal conductivity path ensures that heat can be efficiently exported and dissipated from the chip, making it particularly suitable for application scenarios with extreme requirements for heat dissipation and reliability, such as next-generation high-power devices IGBT, GaN, high-performance computing chips, aerospace electronic systems, etc.

[0028] In one embodiment, the method for preparing yttrium-stabilized zirconium oxide includes the following steps: P1. Prepare the zirconium oxide and alumina powders according to the specified ratio, mix them and wet grind them. The solvent can be anhydrous ethanol, deionized water, or ultrapure water. Then dry, pulverize and sieve. P2. The powder processed in step P1 is sintered, then crushed, ground, and sieved to complete the preparation of yttrium-stabilized zirconium oxide.

[0029] Specifically, in step P1, during the wet grinding process, the ball-to-liquid ratio is (1~5):1:(0.6~2), and the wet grinding time is 6h~48h; wherein, the solvent can be anhydrous ethanol or deionized water or ultrapure water; the wet grinding equipment can be one or more of a drum ball mill, a frame ball mill or a planetary ball mill.

[0030] Specifically, in step P2, the drying temperature is 85℃~150℃, and the drying time is 21h~48h.

[0031] Specifically, in step P2, the sintering temperature is 750℃~1800℃, and the sintering time is 4h~16h. The sintering atmosphere can be air, nitrogen, hydrogen, or a nitrogen-hydrogen mixture.

[0032] Specifically, in step P2, the sample is crushed or dry-ground until it passes through a 40-325 mesh sieve and is mixed evenly.

[0033] The present invention also proposes a ceramic substrate, including the green ceramic sheet; the ceramic substrate includes multiple layers of the green ceramic sheet stacked sequentially, and the content of yttrium-stabilized zirconium oxide in the green ceramic sheet exhibits a gradient change along a direction perpendicular to the ceramic substrate.

[0034] It is understood that this invention constructs a multilayer ceramic substrate with a vertically oriented coefficient of thermal expansion gradient. By controlling the content of yttrium-stabilized zirconium oxide in each green ceramic sheet as a key variable to adjust the coefficient of thermal expansion (CTE), the CTE of each layer exhibits a continuous or regular stepwise change along the direction perpendicular to the substrate plane. Furthermore, the ceramic substrate of this invention, while achieving stress gradient distribution, can simultaneously optimize the thermal conductivity and mechanical strength of individual green ceramic sheets and the entire ceramic substrate, achieving a synergistic improvement in thermal management performance and reliability.

[0035] In one specific embodiment, as the content of the yttrium-stabilized zirconium oxide in the green ceramic sheet increases, the amount of yttrium oxide used to prepare the yttrium-stabilized zirconium oxide decreases.

[0036] It should be noted that yttrium-stabilized zirconia primarily functions as a coefficient of thermal expansion modifier and a phase-stabilizing reinforcing phase in green ceramic sheets. When it is necessary to increase the overall CTE value of a certain layer of green ceramic sheet, the amount of yttrium-stabilized zirconia added to the raw materials of the green ceramic sheet is increased. In green ceramic sheets with increased yttrium-stabilized zirconia addition, choosing yttrium-stabilized zirconia with a lower yttrium oxide doping ratio ensures that the yttrium-stabilized zirconia still has a high CTE value, sufficient to effectively improve the overall CTE value of the green ceramic sheet. Furthermore, it offers lower raw material costs. Yttrium oxide is significantly more expensive than zirconia; by using a low yttrium ratio in high YSZ content layers while meeting performance requirements, the total consumption of the expensive yttrium oxide can be significantly reduced, thereby controlling the overall material cost.

[0037] In one embodiment, the thickness of the ceramic substrate does not exceed 2 mm; in the ceramic substrate, the thickness of each layer of the green ceramic sheet is 0.1 mm to 0.4 mm.

[0038] In one specific embodiment, the coefficients of thermal expansion of adjacent green ceramic sheets forming the same ceramic substrate exhibit a gradient along a direction perpendicular to the ceramic substrate, and the difference in the coefficients of thermal expansion of adjacent green ceramic sheets does not exceed 5 ppm / ℃.

[0039] In a preferred embodiment, the coefficients of thermal expansion of adjacent green ceramic sheets forming the same ceramic substrate exhibit a gradient along a direction perpendicular to the ceramic substrate, and the difference in the coefficients of thermal expansion of adjacent green ceramic sheets does not exceed 1.5 ppm / ℃.

[0040] In a more preferred embodiment, the coefficients of thermal expansion of adjacent green ceramic sheets forming the same ceramic substrate exhibit a gradient along a direction perpendicular to the ceramic substrate, and the difference in the coefficients of thermal expansion of adjacent green ceramic sheets does not exceed 1.4 ppm / ℃.

[0041] In one specific embodiment, the green ceramic sheet comprises the following raw materials: yttrium-stabilized zirconium oxide: 5wt%~25wt%; alumina: 65wt%~85wt%; calcium oxide: 5wt%.

[0042] Specifically, the ceramic substrate includes a first green ceramic layer, a second green ceramic layer, a third green ceramic layer, a fourth green ceramic layer, and a fifth green ceramic layer stacked sequentially. The first green ceramic layer includes 10 wt% yttrium-stabilized zirconium oxide, 85 wt% alumina, and 5 wt% calcium oxide, wherein the yttrium-stabilized zirconium oxide comprises yttrium oxide and zirconium oxide in a weight ratio of 1:1. The second green ceramic layer includes 15 wt% yttrium-stabilized zirconium oxide, 80 wt% alumina, and 5 wt% calcium oxide, wherein the yttrium-stabilized zirconium oxide comprises yttrium oxide and zirconium oxide in a weight ratio of 1:2. The third green ceramic layer includes 20 wt% yttrium-stabilized zirconium oxide, 80 wt% alumina, and 5 wt% calcium oxide, wherein the yttrium-stabilized zirconium oxide comprises yttrium oxide and zirconium oxide in a weight ratio of 1:2. The first layer comprises yttrium-stabilized zirconium oxide (YTO), 75 wt% alumina, and 5 wt% calcium oxide, wherein the YTO-stabilized zirconium oxide comprises yttrium oxide and zirconium oxide in a weight ratio of 1:3; the second layer comprises 25 wt% YTO-stabilized zirconium oxide (YTO), 70 wt% alumina, and 5 wt% calcium oxide, wherein the YTO-stabilized zirconium oxide comprises yttrium oxide and zirconium oxide in a weight ratio of 1:4; the third layer comprises 30 wt% YTO-stabilized zirconium oxide (YTO), 65 wt% alumina, and 5 wt% calcium oxide, wherein the YTO-stabilized zirconium oxide comprises yttrium oxide and zirconium oxide in a weight ratio of 1:5.

[0043] It should be noted that in this embodiment, the coefficient of thermal expansion of the ceramic substrate increases from the first green ceramic layer to the fifth green ceramic layer, rising from 5.4 ppm / ℃ to 10.8 ppm / ℃, and the difference in the coefficient of thermal expansion between adjacent green ceramic sheets does not exceed 1.4 ppm / ℃. This effectively solves the problem of CTE mismatch between heterogeneous materials within the system-in-package. The bending strength of the third green ceramic layer reaches 750 MPa, while the bending strength decreases from the second to the third green ceramic layer.

[0044] In another specific embodiment, the green ceramic sheet comprises the following raw materials: yttrium-stabilized zirconium oxide: 5wt%~25wt%; aluminum nitride: 20wt%~85wt%; alumina: 0wt%~45wt%; calcium oxide: 5wt%.

[0045] Specifically, the ceramic substrate includes a first green ceramic layer, a second green ceramic layer, a third green ceramic layer, a fourth green ceramic layer, and a fifth green ceramic layer stacked sequentially. The first green ceramic layer includes 10 wt% yttrium-stabilized zirconium oxide, 85 wt% aluminum nitride, and 5 wt% calcium oxide, wherein the yttrium-stabilized zirconium oxide comprises yttrium oxide and zirconium oxide in a weight ratio of 1:1. The second green ceramic layer includes 15 wt% yttrium-stabilized zirconium oxide, 80 wt% aluminum nitride, and 5 wt% calcium oxide, wherein the yttrium-stabilized zirconium oxide comprises yttrium oxide and zirconium oxide in a weight ratio of 1:2. The third green ceramic layer includes 20 wt% yttrium oxide. The first layer comprises yttrium-stabilized zirconia, 75 wt% aluminum nitride, and 5 wt% calcium oxide, wherein the yttrium-stabilized zirconia comprises yttrium oxide and zirconia in a weight ratio of 1:3; the second layer comprises 25 wt% yttrium-stabilized zirconia, 70 wt% aluminum nitride, and 5 wt% calcium oxide, wherein the yttrium-stabilized zirconia comprises yttrium oxide and zirconia in a weight ratio of 1:4; the third layer comprises 30 wt% yttrium-stabilized zirconia, 20 wt% aluminum nitride, 45 wt% aluminum oxide, and 5 wt% calcium oxide, wherein the yttrium-stabilized zirconia comprises yttrium oxide and zirconia in a weight ratio of 1:5.

[0046] It should be noted that in this embodiment, the coefficient of thermal expansion of the ceramic substrate increases from the first green ceramic layer to the fifth green ceramic layer, rising from 5.4 ppm / ℃ to 11 ppm / ℃, and the difference in the coefficient of thermal expansion between adjacent green ceramic sheets does not exceed 1.5 ppm / ℃. This effectively solves the problem of CTE mismatch between heterogeneous materials within the system-in-package. The bending strength of the third green ceramic layer reaches 750 MPa, while the bending strength decreases from the second to the third green ceramic layer.

[0047] The present invention also proposes a method for preparing the above-mentioned ceramic substrate, comprising the following steps: S1. Mix the raw materials according to the formula, add solvent and additives, and perform wet milling to prepare green ceramic slurry; S2. The green ceramic slurry is degassed, cast, cut into pieces and stacked, and then subjected to isostatic pressing to obtain a green body. S3. The green body obtained in step S3 is subjected to debinding, pre-firing and sintering in sequence to obtain a semi-finished product; S4. Anneal and post-process the semi-finished product to complete the preparation of the ceramic substrate.

[0048] Specifically, when performing wet milling, one or more of a drum ball mill, a frame ball mill, or a planetary ball mill are used to mix and wet mill the prepared powder. The ball-to-liquid ratio is between 1 and 5:1:0.6 and between 2, and the milling time is between 6 and 60 hours. The solvent can be one or more of alcohols, acrylics, aromatic hydrocarbons, and esters, and dispersants, plasticizers, binders, etc. are added.

[0049] In one embodiment, in step S2, the isostatic pressing pressure is 1000Psi~12000Psi, the temperature is 40℃~85℃, and the holding time is 2min~60min.

[0050] In one embodiment, in step S3, the glue removal temperature is 200℃~650℃, the heating rate is 0.1℃ / min~2℃ / min, the glue removal time is 4h~96h, and the glue removal atmosphere can be air, nitrogen, hydrogen, or a nitrogen-hydrogen mixture.

[0051] In one embodiment, in step S3, the pre-firing temperature is 750°C to 1300°C, and the pre-firing time is 2h to 48h; the pre-firing atmosphere can be air, nitrogen, hydrogen, or a nitrogen-hydrogen mixture.

[0052] In one embodiment, in step S3, the sintering temperature is 750℃~1800℃, the sintering time is 4h~48h, the sintering pressure is 1Mpa~100Mpa, and the sintering atmosphere can be air, nitrogen, hydrogen, or a nitrogen-hydrogen mixture.

[0053] In one embodiment, in step S4, the annealing temperature is 100°C to 300°C lower than the sintering temperature, the annealing time is 1 hour to 8 hours, and the annealing atmosphere can be air, nitrogen, hydrogen, or a nitrogen-hydrogen mixture. It should also be noted that the number of annealing times is not limited; it can be annealed at a single temperature or annealed at multiple cooling times.

[0054] In one embodiment, step S4 includes post-processing such as cleaning, drying, coating, and etching. Specifically, cleaning can be one or more wet cleaning methods such as organic cleaning and inorganic cleaning, or one or more dry cleaning methods such as ion etching and vapor phase cleaning, or one or more dry and wet cleaning methods; the drying temperature is 80℃~150℃, and the drying time is 2h~8h; the seed layer metal for coating includes, but is not limited to, Ti, TiW, Cr, Ni, and Fe, which contain one or more metal compounds, and can be sputtered coating or evaporated coating; etching can be dry etching or wet etching.

[0055] The present invention will be further illustrated below through specific embodiments: The raw materials, reagents, or devices used in the embodiments of this invention are all commercially available. Unless otherwise specified, this invention does not impose any restrictions on the source of raw materials.

[0056] Example 1 The ceramic substrate in Example 1 consists of 5 layers of green ceramic sheets, each with a thickness of 0.3 mm. The specific ratio is shown in Table 1.

[0057] Table 1

[0058] The method for preparing the ceramic substrate in Example 1 includes the following steps: S1. Zirconia and yttrium oxide powders were mixed according to the formula, and solvent was added. The mixture was wet-milled for 24 hours with a ball-to-liquid ratio of 5:1:1. After that, the mixture was dried at 150°C for 48 hours, pulverized, and passed through a 100-mesh sieve. The temperature was increased to 1000°C at a rate of less than 5°C / min, and then increased to 1300°C at a rate of 2°C / min. The temperature was held for 2 hours at a pressure of 20 MPa and the sintering atmosphere was air. After that, the mixture was pulverized, iron removed, ground, and sieved to complete the preparation of yttrium-stabilized zirconia powder. The yttrium-stabilized zirconia powder was then mixed with the remaining powder, and solvent and additives were added. The mixture was wet-milled with a ball-to-liquid ratio of 5:1:1 for 24 hours to prepare a green ceramic slurry. S2. The green ceramic slurry is degassed, cast, cut into pieces and stacked, and then subjected to isostatic pressing at a pressure of 12000 Psi, a temperature of 75°C and a holding time of 10 min to obtain a green body. S3. The green body obtained in step S3 is subjected to debinding, pre-firing, and sintering in sequence. The debinding temperature is 650℃, the heating rate is 0.1℃ / min, and the debinding time is 96h. Then, the temperature is raised to 750℃ for pre-firing for 2h. Then, the temperature is raised to 1000℃ at a heating rate of less than 5℃ / min, and then raised to 1500℃ at a heating rate of 2℃ / min, held for 4h, the pressure is 20MPa, and the sintering atmosphere is air; a semi-finished product is obtained. S4. Anneal and post-process the semi-finished product at a temperature of 1200℃ for 8 hours to complete the preparation of the ceramic substrate.

[0059] After testing, the CTE values ​​of the first to fifth green ceramic layers in the ceramic substrate of Example 1 were 5.4 ppm / ℃, 6.7 ppm / ℃, 8.1 ppm / ℃, 9.4 ppm / ℃ and 10.8 ppm / ℃, respectively. The bending strengths of the first to fifth green ceramic layers in the ceramic substrate in Example 1 are approximately 600 MPa, 700 MPa, 750 MPa, 750 MPa, and 650 MPa, respectively.

[0060] Example 1: The overall bending strength of the ceramic substrate is not less than 600 MPa.

[0061] After testing, the ceramic substrate of Example 1 was found to be undamaged when subjected to temperature shocks exceeding 500°C.

[0062] Example 2 The ceramic substrate in Example 2 consists of 5 layers of green ceramic sheets, each with a thickness of 0.3 mm. The specific ratio is shown in Table 2.

[0063] Table 2

[0064] The difference between the ceramic substrate preparation method in Example 2 and that in Example 1 is that the sintering pressure in step S3 is changed to 100 MPa.

[0065] After testing, the CTE values ​​of the first to fifth green ceramic layers in the ceramic substrate of Example 2 were 5.4 ppm / ℃, 6.7 ppm / ℃, 8 ppm / ℃, 9.5 ppm / ℃ and 11 ppm / ℃, respectively. In Example 2, the flexural strengths of the first to fifth green ceramic layers in the ceramic substrate are approximately 650 MPa, 700 MPa, 750 MPa, 750 MPa, and 700 MPa, respectively.

[0066] Example 2: The overall bending strength of the ceramic substrate is not less than 600 MPa.

[0067] After testing, the ceramic substrate of Example 2 was found to be undamaged when subjected to temperature shocks exceeding 500°C.

[0068] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A type of raw ceramic tile, characterized in that, The raw material for the green ceramic tiles includes yttrium-stabilized zirconium oxide with a mass fraction of 5wt% to 25wt%. The weight ratio of yttrium oxide to zirconium oxide used to prepare the yttrium-stabilized zirconium oxide is 1:1 to 5.

2. The raw ceramic tile as described in claim 1, characterized in that, The raw materials for the green ceramic tiles also include alumina and / or aluminum nitride at a mass fraction of 65wt% to 85wt%.

3. The raw ceramic tile as described in claim 1, characterized in that, The raw materials for the green ceramic tiles include: Yttrium-stabilized zirconium oxide: 5wt%~25wt%; aluminum oxide: 65wt%~85wt%; calcium oxide: 5wt%; Alternatively, the raw materials for the green ceramic tiles may include: Yttrium stabilized zirconium oxide: 5wt%~25wt%; aluminum nitride: 20wt%~85wt%; aluminum oxide: 0wt%~45wt%; calcium oxide: 5wt%.

4. The raw ceramic tile as described in claim 1, characterized in that, The method for preparing the yttrium-stabilized zirconium oxide includes the following steps: P1. Prepare the zirconium oxide and alumina powders according to the specified ratio, mix and wet grind them, then dry, pulverize and sieve them; P2. The powder processed in step P1 is sintered, then crushed, ground, and sieved to complete the preparation of yttrium-stabilized zirconium oxide.

5. A ceramic substrate, characterized in that, The ceramic substrate comprises the green ceramic sheet as described in any one of claims 1 to 4; The ceramic substrate comprises multiple layers of green ceramic sheets stacked sequentially, and the content of yttrium-stabilized zirconium oxide in the green ceramic sheets exhibits a gradient change along a direction perpendicular to the ceramic substrate.

6. The ceramic substrate as described in claim 5, characterized in that, As the content of the yttrium-stabilized zirconium oxide in the green ceramic sheet increases, the amount of yttrium oxide used to prepare the yttrium-stabilized zirconium oxide decreases.

7. The ceramic substrate as described in claim 5, characterized in that, The thickness of the ceramic substrate does not exceed 2 mm; In the ceramic substrate, the thickness of each layer of green ceramic sheet is 0.1mm to 0.4mm.

8. The ceramic substrate as described in claim 5, characterized in that, Along a direction perpendicular to the plane of the ceramic substrate, the coefficients of thermal expansion of adjacent green ceramic sheets exhibit a gradient change, and the difference in the coefficients of thermal expansion of adjacent green ceramic sheets does not exceed 5 ppm / ℃.

9. A method for preparing a ceramic substrate as described in any one of claims 5 to 8, characterized in that, Includes the following steps: S1. Mix the raw materials according to the formula, add solvent and additives, and perform wet milling to prepare green ceramic slurry; S2. The green ceramic slurry is degassed, cast, cut into pieces and stacked, and then subjected to isostatic pressing to obtain a green body. S3. The green body obtained in step S3 is subjected to debinding, pre-firing and sintering in sequence to obtain a semi-finished product; S4. Anneal and post-process the semi-finished product to complete the preparation of the ceramic substrate.

10. The method for preparing a ceramic substrate as described in claim 9, characterized in that, In step S2, the isostatic pressing process is performed at a pressure of 1000 Psi to 12000 Psi, a temperature of 40°C to 85°C, and a holding time of 2 min to 60 min. And / or, in step S3, the glue removal temperature is 200℃~650℃, the heating rate is 0.1℃ / min~2℃ / min, and the glue removal time is 4h~96h; And / or, in step S3, the pre-firing temperature is 750℃~1300℃, and the pre-firing time is 2h~48h; And / or, in step S3, the sintering temperature is 750℃~1800℃, the sintering time is 4h~48h, and the sintering pressure is 1Mpa~100Mpa; And / or, in step S4, the annealing temperature is 100℃~300℃ lower than the sintering temperature, and the annealing time is 1h~8h; And / or, in step S4, the post-processing includes cleaning, drying, coating, and etching.

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