Low temperature co-fired multilayer ceramic substrate and method of making same

Abstract

The application relates to the technical field of ceramic substrates, and discloses a low-temperature co-fired multilayer ceramic substrate and a preparation method thereof.A low-temperature co-fired multilayer ceramic substrate is prepared from the following components in parts by weight: 50-60 parts of aluminum nitride, 50-60 parts of glass powder, 10-16 parts of a binder, 5-15 parts of a plasticizer, 8-14 parts of a reinforcing agent and 100-150 parts of a solvent; the reinforcing agent comprises rare earth oxide powder, basalt fiber and calcium boride powder.Through the technical scheme, the problem of low bending strength of the low-temperature co-fired multilayer ceramic substrate in the related art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ceramic substrate, in particular, relates to a low-temperature co-fired multilayer ceramic substrate and a preparation method thereof. BACKGROUND

[0002] In today's era of rapid development of science and technology, electronic devices are rapidly advancing towards miniaturization and high performance. With the continuous improvement of the integration level of electronic components, low-temperature co-fired multilayer ceramic substrates, as the core support components of electronic devices, are facing unprecedented challenges and extremely stringent requirements on their performance.

[0003] Traditional low-temperature co-fired multilayer ceramic substrates have obvious deficiencies in bending strength. In the production process of electronic devices, this defect brings many difficult problems. In the process of multilayer stacking, welding and subsequent assembly, due to the low bending strength of the substrate, it is easy to deform or even crack when subjected to external force. This not only greatly increases the rate of defective products in the production process, increases the production cost, but also seriously hinders the improvement of production efficiency.

[0004] In the use stage of electronic devices, when the device encounters vibration, impact or thermal stress due to environmental temperature changes, due to the insufficient bending strength of the low-temperature co-fired multilayer ceramic substrate, internal circuit connections are prone to breakage, short circuit and other faults. This not only seriously affects the reliability and stability of electronic devices, but also greatly shortens the service life of the device. Especially in the high-end fields of aerospace, automotive electronics and 5G communication, the miniaturization, lightweight and reliability of electronic devices are extremely high. In the field of aerospace, the aircraft will experience severe vibration and complex temperature changes during flight. If the bending strength of the low-temperature co-fired multilayer ceramic substrate is insufficient, it may cause electronic device failure and endanger flight safety. In the field of automotive electronics, the vibration of the vehicle during driving and the high-temperature environment in the engine compartment are also a great test of the bending strength of the substrate. And 5G communication equipment needs to run stably in various complex environments, and the performance requirements of the substrate are also not to be underestimated.

[0005] Therefore, improving the bending strength of low-temperature co-fired multilayer ceramic substrates has become a key technical problem to be solved, and solving this problem is of great significance. SUMMARY

[0006] The present application provides a low-temperature co-fired multilayer ceramic substrate and a preparation method thereof, which solves the problem of low bending strength of low-temperature co-fired multilayer ceramic substrates in related technologies.

[0007] The technical scheme of the present application is as follows:

[0008] The application provides a low-temperature co-fired multilayer ceramic substrate, raw materials of which comprise the following components in parts by weight: 50-60 parts of aluminum nitride, 50-60 parts of glass powder, 10-16 parts of a binder, 5-15 parts of a plasticizer, 8-14 parts of a reinforcing agent and 100-150 parts of a solvent;

[0009] The reinforcing agent comprises rare earth oxide powder, basalt fiber and calcium boride powder.

[0010] In the application, the addition of the glass powder reduces the sintering temperature, so that the low-temperature co-fired multilayer ceramic substrate is densified at a lower temperature.

[0011] In the application, the addition of the binder enables the various powdery components such as the aluminum nitride and the glass powder to be firmly bonded together to form a green body with a certain shape and strength, so that the green body is ensured not to be cracked or loosened in the subsequent processing and treatment.

[0012] In the application, the addition of the plasticizer makes the green body easier to be demolded and cut in the processing, improves the production efficiency, and also helps to improve the surface quality of the ceramic substrate, so that the ceramic substrate is smoother and more even.

[0013] As a further technical solution, the mass ratio of the rare earth oxide powder, the basalt fiber and the calcium boride powder is 5-7:2:1.

[0014] In the application, by adjusting the mass ratio of the rare earth oxide powder, the basalt fiber and the calcium boride powder to be 5-7:2:1, the bending strength of the low-temperature co-fired multilayer ceramic substrate is further improved.

[0015] As a further technical solution, the raw material of the rare earth oxide powder comprises one or more of yttrium oxide powder, scandium oxide powder and cerium oxide powder.

[0016] As a further technical solution, when the raw material of the rare earth oxide powder comprises the yttrium oxide powder and the scandium oxide powder, the mass ratio of the yttrium oxide powder and the scandium oxide powder is 1-2:5.

[0017] As a further technical solution, the preparation method of the rare earth oxide powder comprises the following steps: mixing the yttrium oxide powder and the scandium oxide powder, and ball milling to obtain the rare earth oxide powder.

[0018] As a further technical solution, when the ball milling is performed, the rotating speed is 200-300 rpm, and the time is 5-7 h.

[0019] In the application, the raw material of the rare earth oxide powder is composed of the yttrium oxide powder and the scandium oxide powder with a mass ratio of 1-2:5, and the rare earth oxide powder obtained by ball milling is added to the low-temperature co-fired multilayer ceramic substrate, so that the dielectric loss of the low-temperature co-fired multilayer ceramic substrate is reduced.

[0020] As a further technical solution, the raw material of the glass powder comprises calcium oxide, magnesium oxide, silicon dioxide, aluminum oxide and lithium oxide;

[0021] The binder comprises one of polyvinyl alcohol and polyvinyl butyral;

[0022] The plasticizer comprises one of dibutyl phthalate and dioctyl phthalate;

[0023] The solvent comprises one of ethanol, n-butanol and isopropyl alcohol.

[0024] As a further technical solution, the mass ratio of the calcium oxide, magnesium oxide, silicon dioxide, aluminum oxide and lithium oxide is 2:2:3:5:1~2;

[0025] The preparation method of the glass powder comprises the following steps: mixing the raw material of the glass powder, melting, water quenching, ball milling, and obtaining the glass powder.

[0026] As a further technical solution, the temperature during melting is 1300~1500℃.

[0027] The application further provides a preparation method of the low-temperature co-fired multilayer ceramic substrate.

[0028] S1, the glass powder is mixed with aluminum nitride, a reinforcing agent is added, ball milling is performed, and a mixture is obtained;

[0029] S2, the mixture is added into a solvent, a plasticizer is added, and a mixed solution is obtained;

[0030] S3, a binder is added into the mixed solution, and uniform mixing is performed, so as to obtain a slurry;

[0031] S4, the slurry is flow-casted and formed, and drying is performed, so as to obtain a green ceramic sheet;

[0032] S5, the green ceramic sheet is perforated, surface printed, laminated, laminated, and sintered, so as to obtain the low-temperature co-fired multilayer ceramic substrate.

[0033] As a further technical solution, the raw material of the surface printing is tungsten slurry;

[0034] During sintering, the temperature is 800~950℃, and the time is 3~5h.

[0035] The working principle and beneficial effects of the application are as follows:

[0036] The reinforcing agent includes rare earth oxide powder, basalt fiber and calcium boride powder, the three synergistically act, the bending strength of the low-temperature co-fired multilayer ceramic substrate is improved, the service life can be prolonged, and the stability of the low-temperature co-fired ceramic substrate in actual application is ensured. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor also fall within the scope of protection of the present application.

[0038] In the following examples and comparative examples, the yttrium oxide powder has a particle size of 325 mesh and a purity of 99.9wt%; the scandium oxide powder has a particle size of 325 mesh and a purity of 99.9wt%; the cerium oxide powder has a particle size of 325 mesh and a purity of 99.9wt%; the basalt fiber has a length of 6mm and a diameter of 17μm; the calcium boride powder has a particle size of 200 mesh and a purity of 97wt%; the polyvinyl alcohol has a model of PVA 17-99; and the polyvinyl butyral has a model of B-76.

[0039] Example 1

[0040] A low-temperature co-fired multilayer ceramic substrate, raw materials including the following components in parts by weight: aluminum nitride 60 parts, glass powder 60 parts, polyvinyl alcohol 16 parts, dibutyl phthalate 15 parts, reinforcing agent 14 parts, ethanol 150 parts;

[0041] The reinforcing agent includes yttrium oxide powder, basalt fiber and calcium boride powder in a mass ratio of 10:2:1;

[0042] The preparation method of the glass powder includes the following steps: mixing calcium oxide, magnesium oxide, silicon dioxide, aluminum oxide and lithium oxide in a mass ratio of 2:2:3:5:2, melting at 1500℃, water quenching, ball milling to a particle size of 3μm, and obtaining the glass powder;

[0043] The preparation method of the low-temperature co-fired multilayer ceramic substrate includes the following steps:

[0044] S1, mixing the glass powder and the aluminum nitride, adding the reinforcing agent, and ball milling to obtain a mixture;

[0045] S2, adding the mixture into ethanol, adding dibutyl phthalate to obtain a mixed solution;

[0046] S3, adding polyvinyl alcohol into the mixed solution and mixing uniformly to obtain a slurry;

[0047] S4, casting and forming the slurry, drying to obtain a green ceramic sheet;

[0048] S5, the green ceramic sheet is punched, the surface is printed with tungsten slurry with a thickness of 20 mu m, 30 layers of green ceramic sheets are laminated, laminated, sintered at 950 DEG C for 3h, and a low-temperature co-fired multilayer ceramic substrate is obtained.

[0049] Example 2

[0050] A low-temperature co-fired multilayer ceramic substrate, the raw material comprises the following components by weight: aluminum nitride 50 parts, glass powder 50 parts, polyvinyl butyral 10 parts, dioctyl phthalate 5 parts, reinforcing agent 8 parts, n-butanol 100 parts;

[0051] The reinforcing agent comprises scandium oxide powder, basalt fiber and calcium boride powder in a mass ratio of 3:2:1;

[0052] The preparation method of the glass powder comprises the following steps: mixing calcium oxide, magnesium oxide, silicon dioxide, aluminum oxide and lithium oxide in a mass ratio of 2:2:3:5:1, melting at 1300 DEG C, water quenching, ball milling to a particle size of 3 mu m, and obtaining glass powder;

[0053] The preparation method of the low-temperature co-fired multilayer ceramic substrate comprises the following steps:

[0054] S1, the glass powder is mixed with aluminum nitride, the reinforcing agent is added, and the mixture is obtained by ball milling;

[0055] S2, the mixture is added to n-butanol, and dioctyl phthalate is added to obtain a mixed solution;

[0056] S3, polyvinyl butyral is added to the mixed solution, and the mixture is uniformly mixed to obtain a slurry;

[0057] S4, the slurry is cast into a green ceramic sheet;

[0058] S5, the green ceramic sheet is punched, the surface is printed with tungsten slurry with a thickness of 20 mu m, 30 layers of green ceramic sheets are laminated, laminated, sintered at 800 DEG C for 5h, and a low-temperature co-fired multilayer ceramic substrate is obtained.

[0059] Example 3

[0060] A low-temperature co-fired multilayer ceramic substrate, the raw material comprises the following components by weight: aluminum nitride 55 parts, glass powder 55 parts, polyvinyl alcohol 13 parts, dibutyl phthalate 10 parts, reinforcing agent 12 parts, isopropyl alcohol 120 parts;

[0061] The reinforcing agent comprises cerium oxide powder, basalt fiber and calcium boride powder in a mass ratio of 8:2:1;

[0062] The preparation method of the glass powder comprises the following steps: mixing calcium oxide, magnesium oxide, silicon dioxide, aluminum oxide and lithium oxide in a mass ratio of 2:2:3:5:1, melting at 1400 DEG C, water quenching, ball milling to a particle size of 3 microns, and obtaining the glass powder.

[0063] The preparation method of the low-temperature co-fired multilayer ceramic substrate comprises the following steps:

[0064] S1, mixing the glass powder and aluminum nitride, adding a reinforcing agent, ball milling, and obtaining a mixture;

[0065] S2, adding the mixture into isopropyl alcohol, adding dibutyl phthalate, and obtaining a mixed solution;

[0066] S3, adding polyvinyl butyral into the mixed solution, mixing uniformly, and obtaining a slurry;

[0067] S4, flow casting the slurry, drying, and obtaining a green ceramic sheet;

[0068] S5, perforating the green ceramic sheet, printing tungsten slurry with a thickness of 20 microns on the surface, laminating 30 layers of green ceramic sheets, and sintering at 900 DEG C for 4 hours, and obtaining a low-temperature co-fired multilayer ceramic substrate.

[0069] Example 4

[0070] The difference between this embodiment and example 3 is that the mass ratio of cerium oxide powder, basalt fiber and calcium boride powder in this embodiment is 4:2:1.

[0071] Example 5

[0072] The difference between this embodiment and example 3 is that the mass ratio of cerium oxide powder, basalt fiber and calcium boride powder in this embodiment is 5:2:1.

[0073] Example 6

[0074] The difference between this embodiment and example 3 is that the mass ratio of cerium oxide powder, basalt fiber and calcium boride powder in this embodiment is 7:2:1.

[0075] Example 7

[0076] The difference between this embodiment and example 6 is that the cerium oxide powder in this embodiment is replaced by an equal amount of rare earth oxide powder composed of yttrium oxide powder and scandium oxide powder in a mass ratio of 3:5.

[0077] The preparation method of the rare earth oxide powder comprises the following steps: mixing yttrium oxide powder and scandium oxide powder, ball milling at 300 rpm for 5 hours, and obtaining the rare earth oxide powder.

[0078] Example 8

[0079] The difference between this example and Example 6 is that the cerium oxide powder in this example is replaced with an equal amount of a rare earth oxide powder composed of yttrium oxide powder and cerium oxide powder in a mass ratio of 3:5.

[0080] The method for preparing the rare earth oxide powder includes the following steps: mixing the yttrium oxide powder and the cerium oxide powder, ball milling for 5 h at 300 rpm, and obtaining the rare earth oxide powder.

[0081] Example 9

[0082] The difference between this example and Example 6 is that the cerium oxide powder in this example is replaced with an equal amount of a rare earth oxide powder composed of cerium oxide powder and scandium oxide powder in a mass ratio of 3:5.

[0083] The method for preparing the rare earth oxide powder includes the following steps: mixing the cerium oxide powder and the scandium oxide powder, ball milling for 5 h at 300 rpm, and obtaining the rare earth oxide powder.

[0084] Example 10

[0085] The difference between this example and Example 7 is that the mass ratio of the yttrium oxide powder and the scandium oxide powder in this example is 1:7.

[0086] Example 11

[0087] The difference between this example and Example 7 is that the mass ratio of the yttrium oxide powder and the scandium oxide powder in this example is 1:5.

[0088] Example 12

[0089] The difference between this example and Example 7 is that the mass ratio of the yttrium oxide powder and the scandium oxide powder in this example is 2:5.

[0090] Comparative Example 1

[0091] The difference between this comparative example and Example 3 is that the reinforcing agent in this comparative example is cerium oxide powder.

[0092] Comparative Example 2

[0093] The difference between this comparative example and Example 3 is that the reinforcing agent in this comparative example is basalt fiber.

[0094] Comparative Example 3

[0095] The difference between this comparative example and Example 3 is that the reinforcing agent in this comparative example is calcium boride powder.

[0096] Comparative Example 4

[0097] The difference between the present comparative example and Example 3 is that the reinforcing agent of the present comparative example is cerium oxide powder and basalt fiber in a mass ratio of 8:2.

[0098] Comparative Example 5

[0099] The difference between the present comparative example and Example 3 is that the reinforcing agent of the present comparative example is cerium oxide powder and basalt fiber in a mass ratio of 8:2.

[0100] Comparative Example 6

[0101] The difference between the present comparative example and Example 3 is that the reinforcing agent of the present comparative example is cerium oxide powder and basalt fiber in a mass ratio of 8:2.

[0102] Comparative Example 7

[0103] The difference between the present comparative example and Example 3 is that the reinforcing agent of the present comparative example is cerium oxide powder and basalt fiber in a mass ratio of 8:2.

[0104] Experimental Example 1

[0105] The low-temperature co-fired multilayer ceramic substrates prepared in Examples 1-6 and Comparative Examples 1-7 were tested for the bending strength of the samples according to the test method specified in GB / T 6569-2006 “Fine Ceramic Bending Strength Test Method”, and the test method was three-point bending. The test results are shown in Table 1.

[0106] Table 1: Bending strength test results

[0107]

[0108] As can be seen from Table 1, the bending strength of the low-temperature co-fired multilayer ceramic substrates prepared in Examples 1-6 of the present application is above 401 MPa, which indicates that the use of rare earth oxide powder, basalt fiber and calcium boride powder as reinforcing agent improves the bending strength of the low-temperature co-fired multilayer ceramic substrate.

[0109] Experimental Example 2

[0110] The low-temperature co-fired multilayer ceramic substrates prepared in Examples 6-12 were tested for the dielectric loss using a broadband dielectric impedance meter E4990A, and the test frequency was 10 6 Hz, and the dielectric loss value of the multilayer ceramic substrate was read. The test results are shown in Table 2.

[0111] Table 2: Dielectric loss test results

[0112]

[0113] As can be seen from Table 2, the dielectric loss of the low-temperature co-fired multilayer ceramic substrates prepared in Examples 7 and 10-12 of the present application is 4.12 x 10 -4When the rare earth oxide powder is used with yttrium oxide powder and scandium oxide powder, the dielectric loss of the low-temperature co-fired multilayer ceramic substrate is reduced.

[0114] The above merely provides the preferred embodiments of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall fall within the protection scope of the present application.

Claims

1. A low-temperature co-fired multilayer ceramic substrate, characterized in that, The raw materials include the following components in parts by weight: 50-60 parts aluminum nitride, 50-60 parts glass powder, 10-16 parts binder, 5-15 parts plasticizer, 8-14 parts reinforcing agent, and 100-150 parts solvent; The reinforcing agent includes rare earth oxide powder, basalt fiber and calcium boride powder; The mass ratio of the rare earth oxide powder, basalt fiber and calcium boride powder is 5~7:2:1; The raw materials for the rare earth oxide powder include yttrium oxide powder and scandium oxide powder, and the mass ratio of yttrium oxide powder to scandium oxide powder is 1~2:

5.

2. The low-temperature co-fired multilayer ceramic substrate according to claim 1, characterized in that, The method for preparing the rare earth oxide powder includes the following steps: mixing yttrium oxide powder and scandium oxide powder, ball milling, and obtaining rare earth oxide powder.

3. The low-temperature co-fired multilayer ceramic substrate according to claim 1, characterized in that, The raw materials for the glass powder include calcium oxide, magnesium oxide, silicon dioxide, aluminum oxide, and lithium oxide; The adhesive includes one of polyvinyl alcohol and polyvinyl butyral; The plasticizer includes one of dibutyl phthalate and dioctyl phthalate; The solvent includes one of ethanol, n-butanol, and isopropanol.

4. The low-temperature co-fired multilayer ceramic substrate according to claim 3, characterized in that, The mass ratio of calcium oxide, magnesium oxide, silicon dioxide, aluminum oxide and lithium oxide is 2:2:3:5:1~2; The method for preparing the glass powder includes the following steps: mixing the raw materials for glass powder, melting, water-cooling and quenching, and ball milling to obtain glass powder.

5. The low-temperature co-fired multilayer ceramic substrate according to claim 4, characterized in that, The melting temperature is 1300~1500℃.

6. A method for preparing a low-temperature co-fired multilayer ceramic substrate, used to prepare a low-temperature co-fired multilayer ceramic substrate as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Mix glass powder with aluminum nitride, add reinforcing agent, and ball mill to obtain a mixture; S2. Add the mixture to a solvent, add a plasticizer, and obtain a mixed solution; S3. Add binder to the mixture and mix evenly to obtain a slurry; S4. Cast the slurry into a mold, dry it, and obtain a raw ceramic tile; S5. The raw ceramic sheet is perforated, surface printed, stacked, laminated, and sintered to obtain a low-temperature co-fired multilayer ceramic substrate.

7. The method for preparing a low-temperature co-fired multilayer ceramic substrate according to claim 6, characterized in that, The material used for surface printing is tungsten paste; The sintering process is carried out at a temperature of 800-950℃ for 3-5 hours.

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