Aluminum oxide ceramic substrate with high cold and hot impact resistance and preparation method of aluminum oxide ceramic substrate

Abstract

The invention discloses an aluminum oxide ceramic substrate with high cold and hot impact resistance and a preparation method thereof, and relates to the technical field of ceramic substrates. The aluminum oxide ceramic substrate is prepared from the following raw material components in parts by mass: 60 to 65 parts of aluminum oxide, 1 to 5 parts of modified glass powder and 0.05 to 0.2 part of magnesium oxide; the modified glass powder comprises magnesium oxide, silicon oxide and calcium carbonate, and 0.5-2.5 wt% of zirconium oxide is doped in the modified glass powder. According to the aluminum oxide ceramic substrate disclosed by the invention, the specific glass powder with high magnesium oxide content is adopted, so that devitrification can be reduced, and bubble defects can be reduced; meanwhile, a specific amount of zirconium oxide is doped in the glass powder, so that the sintering temperature required by the aluminum oxide substrate can be effectively reduced, the compactness of the material is increased, and the cold and hot impact resistance is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ceramic substrate, in particular to an alumina ceramic substrate with high cold and hot impact resistance and a preparation method thereof. BACKGROUND

[0002] As an important ceramic material, alumina substrate is widely used in electronic components, integrated circuits, LED packaging and other fields due to its excellent electrical insulation, high thermal conductivity and mechanical strength. The performance of alumina substrate directly affects the reliability and service life of electronic devices, and the cold and hot impact resistance is one of the key indicators to measure its reliability. Especially in extreme environments where high temperature and low temperature change alternately, the substrate needs to have good thermal shock resistance to ensure that it will not crack or degrade in performance under thermal stress, thereby meeting the demand for high reliability applications.

[0003] In the traditional preparation method of alumina substrate, glass powder is usually used as a fluxing agent or a bonding phase, and the raw materials are mixed by ball milling process. This method aims to reduce the sintering temperature and improve the density of the substrate by introducing glass phase. For example, a low-temperature co-fired porcelain, a preparation method and a ceramic substrate in patent CN116102340A introduce modified calcium borosilicate glass powder into the ceramic powder, so that the ceramic substrate has acid and alkali corrosion resistance, and meets the application reliability of the ceramic substrate after chemical plating. However, the alumina substrate prepared by this method has insufficient cold and hot impact resistance, and the substrate is prone to delamination or cracking in extreme environments of high temperature or low temperature, which limits its application in fields such as aerospace and automotive electronics with high reliability requirements. SUMMARY

[0004] Therefore, in view of the deficiencies of the prior art ceramic substrate, the present application provides an alumina ceramic substrate with high cold and hot impact resistance, which has high density and bending strength, and good cold and hot impact resistance.

[0005] The alumina ceramic substrate of the present application comprises the following components by mass:

[0006] alumina 60-65 parts, modified glass powder 1-5 parts, magnesium oxide 0.05-0.2 parts;

[0007] The modified glass powder comprises: magnesium oxide 36-41 parts, silicon oxide 50-56 parts, calcium carbonate 8.8-9.3 parts; and the modified glass powder is doped with 0.5-2.5wt% zirconium oxide.

[0008] The alumina ceramic substrate of the present application adopts glass powder doped with a specific amount of zirconium oxide in a glass powder of specific components, the zirconium oxide in the glass powder system is in tetragonal phase structure, and is converted into monoclinic phase zirconium oxide and accompanied by volume expansion when stressed, the lattice phase change process can fill the micro-cracks and consume the fracture energy, and the glass phase at the grain boundary between the alumina grains is beneficial to improve the fracture toughness of the alumina ceramic substrate and improve the cold and hot impact resistance.

[0009] Among them, since the ionic radius of Zr 4+ is the largest, when Zr 4+ is doped into the glass powder, it will cause distortion of the glass network structure, increase the reactivity of the glass powder, effectively reduce the required sintering temperature of the alumina substrate when used for sintering of the alumina ceramic substrate, increase the density of the material after sintering, and improve the cold and hot impact resistance.

[0010] Preferably, the D50 particle size of the magnesium oxide in the alumina ceramic substrate is 0.1-2 μm. On the one hand, the magnesium oxide reacts with the alumina to form magnesium aluminate spinel (MgAl2O4), and these particles are pinned at the grain boundaries of the alumina matrix, limiting the grain boundary movement through mechanical resistance and inhibiting abnormal grain growth. On the other hand, small-sized and uniformly distributed MgO particles have good pinning effect after sintering, which is beneficial to improve the density of the alumina matrix. The content of magnesium oxide also needs to be controlled, and excessive addition will further refine the grains, but due to the generation of other phases, the density of the alumina matrix will decrease.

[0011] In some embodiments, the D50 particle size of the modified glass powder is 1-2 μm.

[0012] In some embodiments, the mass ratio of calcium carbonate and magnesium oxide in the modified glass powder is (0.22-0.25):1. When the ratio of calcium carbonate and magnesium oxide increases, the thermal expansion coefficient of the glass powder will increase, and vice versa; the present application optimizes the ratio of calcium carbonate and magnesium oxide to obtain a suitable expansion coefficient, which can increase the density of the material after sintering and improve the cold and hot impact resistance when Zr 4+ is doped.

[0013] It should be noted that the content of magnesium oxide in the modified glass powder of the present application is much higher than that of calcium carbonate; on the one hand, the magnesium oxide in the modified glass powder system partially replaces the calcium carbonate, thereby reducing crystallization and helping to make the glass powder system have a uniform amorphous structure; on the other hand, the magnesium oxide can promote the decomposition of calcium carbonate, avoid the residual of bubbles in the glass liquid, and reduce bubble defects.

[0014] In some embodiments, the preparation method of the modified glass powder comprises the following steps:

[0015] (1) uniformly ball-milling magnesium oxide, silicon oxide and calcium carbonate, and heating to melting to obtain a glass liquid;

[0016] (2) doping zirconium oxide into the glass liquid and stirring to uniformly disperse, and water quenching to obtain the modified glass powder.

[0017] In some embodiments, the heating to melting is specifically heating to 340-360℃ at a heating rate of 8-12℃ / min, heating to 540-560℃ at a heating rate of 3-5℃ / min and holding for 1-2h, and heating to 1490-1510℃ at a heating rate of 7-9℃ / min and holding for 1-2h.

[0018] In some embodiments, in the preparation method of the modified glass powder, the glass powder material obtained in step (2) is further subjected to surface treatment with a silane coupling agent. Preferably, the silane coupling agent is KH-570 coupling agent.

[0019] In some embodiments, further comprising: 0.5-1.5 parts of dispersant, 3-7 parts of binder, and 1-3 parts of plasticizer.

[0020] Preferably, the dispersant is fish oil and / or phosphate ester.

[0021] Preferably, the binder is polyvinyl butyral (PVB).

[0022] Preferably, the plasticizer is dibutyl phthalate (DBP) and / or dioctyl phthalate (DOP).

[0023] Preferably, the solvent is a mixture of toluene / ethanol, and the mass ratio of toluene / ethanol is 1:1.5-2.5.

[0024] The application also provides an alumina ceramic substrate prepared by the above method.

[0025] S1, dispersing a formula amount of the alumina ceramic substrate raw material components in a solvent and stirring to obtain a ceramic slurry;

[0026] S2, casting the ceramic slurry into a film, punching, and sintering at 1580-1600℃ to obtain the alumina ceramic substrate.

[0027] In some embodiments, in step S1, the viscosity of the ceramic slurry at 25℃ is 4000-6000m·s, and the solid content is 35-45vol.%.

[0028] In some embodiments, the flow film forming uses segmented heating, with temperatures of 32-38℃, 52-58℃, 75-85℃, and 115-125℃, respectively.

[0029] In some embodiments, a powder coating process is performed before sintering, with the powder being spherical alumina, and the powder coating amount being 0.2-0.5g / m 2 .

[0030] The present application provides a ceramic-based copper-clad plate (DBC), which is made of a copper foil bonded to the surface of an alumina ceramic substrate.

[0031] In some embodiments, the ceramic-based copper-clad plate is prepared by the following steps:

[0032] (1) heating the copper foil to 850-950℃ in oxygen-containing nitrogen (O2 concentration 50-200ppm) to form a Cu2O oxide layer;

[0033] (2) laminating the alumina substrate and the copper foil, and heating to 1065-1083℃ in a nitrogen-oxygen mixed atmosphere (O2 content 0.1-0.3%) for 10-30 minutes;

[0034] (3) cooling to 800℃ at a rate of 10-20℃ / min, and then slowly cooling to room temperature at a rate of 4-6℃ / min.

[0035] Compared with the prior art, the present application has the following advantages:

[0036] The present application provides an alumina ceramic substrate, which uses a specific glass powder with a high magnesium oxide content, can reduce crystallization and reduce bubble defects; at the same time, the glass powder is doped with a specific amount of zirconium oxide, which can effectively reduce the sintering temperature required for the alumina substrate, increase the density of the material, and improve the cold-thermal shock resistance. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 Figure 1 is a photograph of the alumina ceramic substrate copper-clad plate of Example 1 of the present application after cold-thermal shock resistance testing.

[0038] Figure 2 Figure 2 is a photograph of the alumina ceramic substrate copper-clad plate of Example 2 of the present application after cold-thermal shock resistance testing. DETAILED DESCRIPTION

[0039] The present application will be further described below in conjunction with specific embodiments, but the embodiments do not limit the present application in any form. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present application are commercially available.

[0040] Examples 1-12

[0041] A method for preparing an alumina ceramic substrate comprises the following steps:

[0042] S1, dispersing the raw material components in a solvent and stirring them uniformly to obtain a ceramic slurry;

[0043] Calculated by mass percentage, the raw material components include: 63.4 parts of aluminum oxide, 3-4 parts of modified glass powder, 0.1-0.2 parts of magnesium oxide, 1.1 parts of dispersant, 4.6 parts of binder, 2.1 parts of plasticizer, and 25.3 parts of solvent.

[0044] The specific contents of the modified glass powder and magnesium oxide in each embodiment are shown in Table 1.

[0045] Wherein, the dispersant is triethyl phosphate;

[0046] The binder is polyvinyl butyral (PVB);

[0047] The plasticizer is dibutyl phthalate (DBP);

[0048] The solvent was a toluene / ethanol mixture (mass ratio 1:2).

[0049] The ceramic slurry meets the following requirements: a viscosity of 4000-6000 m·s at 25°C and a solids content of 35-45 vol%. Excessively low or high viscosity can affect slurry fluidity, impacting the quality of the film produced during tape casting. A low solids content can reduce green tape strength, while a high solids content can reduce slurry viscosity, leading to particle agglomeration or coating defects.

[0050] S2, casting the ceramic slurry into a film, punching, applying powder, and sintering to obtain the alumina ceramic substrate.

[0051] Specifically,

[0052] The cast film forming process adopts segmented heating in the film forming production line, with the temperatures being 35°C, 55°C, 80°C and 120°C respectively; the casting rate is 0.4m / min, and the thickness of the obtained cast film is within the range of 0.5-1.2mm.

[0053] The punching process is as follows: the cast film sheet is punched on a punching machine, and the thickness shrinkage rate is controlled within the range of 13-22% to obtain a green film sheet.

[0054] The powder coating is made of spherical alumina with a particle size range of 10-30 μm, and the powder coating amount is 0.2-0.5g / m 2 .

[0055] The sintering conditions are: 0.5℃ / min to 350℃, 2℃ / min to 500℃; 500℃ for 1h; 10℃ / min to 1300℃; 3℃ / min to 1600℃; 1600℃ for 4h; 10℃ / min to 1250℃; furnace cooling.

[0056] The preparation method of the modified glass powder comprises the following steps:

[0057] (1) uniformly ball-milling the formula amount of magnesium oxide, silicon oxide and calcium carbonate, and then heating to melting to obtain a glass liquid.

[0058] The heating to melting is specifically: heating to 350℃ at a heating rate of 10℃ / min, heating to 550℃ at a heating rate of 4℃ / min and holding for 1.5h, and heating to 1500℃ at a heating rate of 8℃ / min and holding for 1h.

[0059] (2) doping the formula amount of zirconium oxide into the glass liquid and stirring to disperse uniformly, and then water quenching to cool to obtain the modified glass powder.

[0060] (3) soaking the modified glass powder in KH-570 silane coupling agent for 1.5h, drying and then sieving to obtain a modified glass powder with a D50 particle size of 1-2μm.

[0061] The mass percentage of the glass powder components and the zirconium oxide and the doping amount of the glass powder are shown in Table 1.

[0062] Table 1

[0063]

[0064] Example 15

[0065] A ceramic-based copper-clad plate (DCB), and a preparation method thereof, the preparation method comprising the following steps:

[0066] (1) using the aluminum oxide ceramic substrate obtained in Example 1, and controlling the thickness to be 0.38mm;

[0067] (1) heating a copper foil with a thickness of 0.3mm to 900℃ in oxygen-containing nitrogen gas (O2concentration 120ppm) to form a Cu2O oxidation layer;

[0068] (2) laminating the aluminum oxide substrate and the copper foil, and heating to 1080℃ in a nitrogen-oxygen mixed atmosphere (O2content 0.2%) for 20min;

[0069] (3) after cooling to 800℃ at a rate of 15℃ / min, slowly cooling to room temperature at a rate of 5℃ / min, and then obtaining the product.

[0070] Comparative Example 1

[0071] A method for preparing an alumina ceramic substrate, which is different from example 2 in that no magnesium oxide is added to the ceramic slurry of the present example.

[0072] The ceramic slurry components include, by mass percentage, 63.4 parts of alumina, 3.4 parts of modified glass powder, 1.1 parts of dispersant, 4.6 parts of binder, 2.1 parts of plasticizer, and 25.3 parts of solvent.

[0073] Comparative example 2

[0074] A method for preparing an alumina ceramic substrate, which is different from example 2 in that the components of the glass liquid of the present comparative example are, by mass parts, 39.17 parts of magnesium oxide, 53 parts of silicon oxide, and 7.83 parts of calcium carbonate.

[0075] Comparative example 3

[0076] A method for preparing an alumina ceramic substrate, which is different from example 2 in that the components of the glass liquid of the present comparative example are, by mass parts, 36.72 parts of magnesium oxide, 53 parts of silicon oxide, and 10.28 parts of calcium carbonate.

[0077] Comparative example 4

[0078] A method for preparing an alumina ceramic substrate, which is different from example 2 in that the modified glass powder of the present comparative example is not doped with zirconium oxide.

[0079] Comparative example 5

[0080] A method for preparing an alumina ceramic substrate, which is different from example 2 in that the modified glass powder of the present comparative example is doped with 3wt.% of zirconium oxide.

[0081] Performance test

[0082] The alumina ceramic substrate samples of examples 1-14 and comparative examples 1-5 above and the ceramic substrate copper-clad plates prepared therefrom using the method of example 15 were subjected to the following performance tests, and the results are shown in Table 2.

[0083] Test method for the density of the cast green body: the weight (m) of the green body was measured using a high-precision electronic balance, then the size of the green body was measured using a vernier caliper and the volume (V) was calculated, and the density of the cast green body was calculated from the weight and the volume, with the formula ρ = m / V.

[0084] Test method for the density of the substrate: similarly, the weight of the substrate was measured using a high-precision electronic balance, then the volume was measured by the drainage method, and the density of the substrate was calculated from the weight and the volume.

[0085] The test method of the substrate bending strength is as follows: the sample size is 80mm*13mm, the three-point bending test method is adopted, the ceramic substrate is placed on the test device, a gradually increasing force is applied, and the bending strength is measured.

[0086] The test method of the copper-clad plate cold-thermal shock resistance is as follows: a thermal shock test box is used for experiment, the high and low temperature range is converted from-55 DEG C to 150 DEG C, the high and low temperature respectively lasts for 30 minutes, the conversion time is less than 30s, the cold-thermal cycle is repeated until the copper-clad plate peels or delaminates, and the cold-thermal cycle period is recorded.

[0087] As shown in Figures 1-2 , it can be seen that after repeated cold-thermal cycle, the copper-clad plate appears delamination phenomenon between copper and substrate Figure 1 , or peeling phenomenon that the copper plate separates from the alumina ceramic substrate with part of the ceramic Figure 2 .

[0088] Table 2

[0089]

[0090]

[0091] As shown in Table 1, the density of the cast green body prepared by the application reaches 2.51g / cm 3 , and the density of the sintered substrate reaches 3.75g / cm 3 , which is higher than that of the comparative example 1.

[0092] Compared with the example 2, the density of the ceramic substrate and the cold-thermal shock resistance of the comparative example 1 decrease because no magnesium oxide is added in the ceramic slurry.

[0093] In the comparative examples 2-3, the content of calcium carbonate in the glass liquid is too low or too high, which leads to the expansion coefficient of the modified glass powder being too large or too small, and thus the cold-thermal shock resistance decreases.

[0094] In the comparative examples 4-5, no zirconium oxide is added or excessive zirconium oxide is doped in the modified glass powder, which reduces the density of the ceramic substrate and decreases the cold-thermal shock resistance.

[0095] The above examples of the application are only examples for clearly illustrating the application, and are not intended to limit the embodiments of the application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments are not required to be exhausted. Any modification, equivalent replacement and improvement made within the spirit and principle of the application should be included in the protection scope of the claims of the application.

Claims

1. An alumina ceramic substrate, characterized in that The raw materials include the following components in parts by mass: 60-65 parts of aluminum oxide, 1-5 parts of modified glass powder, and 0.05-0.2 parts of magnesium oxide; The modified glass powder comprises: 36-41 parts of magnesium oxide, 50-56 parts of silicon oxide, and 8.8-9.3 parts of calcium carbonate; and the modified glass powder is doped with 0.5-2.5wt% of zirconium oxide.

2. The alumina ceramic substrate according to claim 1, characterized in that: In parts by mass, the mass ratio of calcium carbonate to magnesium oxide in the modified glass powder is (0.22-0.25):

1.

3. The alumina ceramic substrate according to claim 1, characterized in that: The method for preparing the modified glass powder comprises the following steps: (1) After ball-milling magnesium oxide, silicon oxide and calcium carbonate, the mixture is heated until melted to obtain glass liquid; (2) adding zirconium oxide into the glass liquid and stirring and dispersing the mixture uniformly, and then quenching the mixture with water to obtain the modified glass powder.

4. The alumina ceramic substrate according to claim 3, characterized in that: The heating to melting is specifically: heating to 340-360°C at a heating rate of 8-12°C / min, heating to 540-560°C at a heating rate of 3-5°C / min and keeping warm for 1-2 hours, heating to 1490-1510°C at a heating rate of 7-9°C / min and keeping warm for 1-2 hours.

5. The alumina ceramic substrate according to claim 3, characterized in that: In the preparation method of the modified glass powder, the glass powder material obtained in step (2) is further surface-treated with a silane coupling agent.

6. The alumina ceramic substrate according to claim 1, characterized in that: The D50 particle size of the magnesium oxide is 0.1-2 μm.

7. The alumina ceramic substrate according to claim 1, characterized in that: Also includes: Dispersant 0.5-1.5 parts, binder 3-7 parts, plasticizer 1-3 parts.

8. A method for preparing the alumina ceramic substrate according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, dispersing the raw material components of the alumina ceramic substrate in a solvent and stirring them uniformly to obtain a ceramic slurry; S2, casting the ceramic slurry into a film, punching out sheets, and sintering at 1580-1600° C. to obtain the alumina ceramic substrate.

9. The method for preparing an alumina ceramic substrate according to claim 8, characterized in that: In step S1, the ceramic slurry has a viscosity of 4000-6000 mPa·s at 25°C.

10. A ceramic substrate copper clad plate, characterized in that: The invention is made of the alumina ceramic substrate according to any one of claims 1 to 7 and bonded with copper foil on the surface.

Images