阅读说明：本技术 一种氮化铝陶瓷粉体、其制备方法和封装基板 (Aluminum nitride ceramic powder, preparation method thereof and packaging substrate ) 是由 宋锡滨 王海超 李心勇 潘光军 于 2020-04-28 设计创作，主要内容包括：本发明提供了一种氮化铝陶瓷粉体、其制备方法和封装基板。该氮化铝陶瓷粉体在20～70GHz范围内的介电常数为7.8～9.0。基于上述介电性能,该氮化铝陶瓷粉体可以用于5G通讯消费电子芯片封装陶瓷基板或玻璃陶瓷共烧基板。(The invention provides aluminum nitride ceramic powder, a preparation method thereof and a packaging substrate. The dielectric constant of the aluminum nitride ceramic powder is 7.8-9.0 within the range of 20-70 GHz. Based on the dielectric property, the aluminum nitride ceramic powder can be used for a 5G communication consumer electronic chip packaging ceramic substrate or a glass ceramic co-fired substrate.)

1. The aluminum nitride ceramic powder is characterized in that the dielectric constant of the aluminum nitride ceramic powder is 7.8-9.0 within the range of 20-70 GHz.

2. The aluminum nitride ceramic powder according to claim 1, wherein the aluminum nitride ceramic powder has a dielectric loss tangent of 0.002 to 0.008 at 20 to 70 GHz.

3. A preparation method of aluminum nitride ceramic powder is characterized by comprising the following steps:

step S1, carrying out wet ball milling and mixing on an aluminum source, a carbon source and a solvent to form a wet mixture;

step S2, drying the wet mixture in a high-pressure fluid atmosphere to obtain a precursor;

step S3, nitriding the precursor to obtain a semi-finished product containing aluminum nitride and an excessive carbon source; and

and step S4, performing decarbonization treatment on the semi-finished product to obtain aluminum nitride ceramic powder.

4. The method for preparing a composite material according to claim 3, wherein the step S2 includes:

placing the wet mixture into a drying chamber, heating the wet mixture, and introducing gas into the drying chamber to increase the pressure of the drying chamber, wherein the gas is inert gas or nitrogen, and the gas outlet is arranged above the wet mixture;

heating the wet mixture to a predetermined temperature, and releasing pressure when the pressure in the drying chamber is greater than a predetermined pressure so as to maintain the pressure in the drying chamber at a predetermined pressure;

and when the gas introduction is stopped, the pressure in the closed drying chamber does not rise any more to indicate that the drying is finished, and the precursor is obtained.

5. The method according to claim 4, wherein the predetermined pressure is 1.0 to 4.0MPa, preferably 1.2 to 2.0MPa, and the predetermined temperature is 100 to 250 ℃, preferably 150 to 200 ℃.

6. The method according to claim 4, wherein the gas has a flow rate of 5 to 100L/min, preferably 15 to 20L/min.

7. The method according to claim 4, wherein the wet mixture is stirred during the step S2, preferably at a stirring speed of 20rpm to 200 rpm.

8. The method of claim 3, wherein the solvent is water or an organic solvent, preferably the organic solvent is ethanol, ethylene glycol or propanol.

9. The method for preparing a composite material according to claim 3, wherein the step S3 includes:

and reacting the precursor in a nitriding atmosphere at 1400-1600 ℃ for 2-10 h to obtain the semi-finished product, wherein the nitriding atmosphere is preferably nitrogen, or a mixed gas of nitrogen and hydrogen, or a mixed gas of nitrogen and ammonia.

10. The method for preparing a composite material according to claim 3, wherein the step S4 includes:

and (3) keeping the semi-finished product at 550-700 ℃ for 2-6 h in air or oxygen-containing mixed gas for decarbonization to obtain the aluminum nitride ceramic powder.

11. An aluminum nitride ceramic powder prepared by the preparation method of any one of claims 3 to 10.

12. A package substrate comprising the aluminum nitride ceramic powder, wherein the aluminum nitride ceramic powder is the aluminum nitride ceramic powder of claim 1, 2 or 11.

Technical Field

The invention relates to the field of preparation of aluminum nitride ceramic powder, in particular to aluminum nitride ceramic powder, a preparation method thereof and a packaging substrate.

Background

The aluminum nitride ceramic has high thermal conductivity, good electrical insulation and low dielectric loss, and is an ideal substrate material and electronic device packaging material. The performance of aluminum nitride powder has an important influence on the performance of substrate materials, and with the rapid development of microelectronic technology, microwave devices and millimeter wave devices are widely applied, and high-performance aluminum nitride becomes one of the hot spots of current research. The carbothermic method is the most widely used preparation method at present, and generally, an aluminum source and a carbon source are uniformly mixed and then placed in a nitrogen atmosphere to be heated and react to obtain aluminum nitride powder. In the nitridation reaction stage, the sufficient reaction of precursors of an aluminum source and a carbon source with nitrogen is particularly important, and in the reaction process of the aluminum source and the carbon source, the state of an interface directly has important influence on the performance of the material, the sintering forming and the dielectric property of the material.

At present, a ball milling mixing process is mostly adopted for mixing an aluminum source and a carbon source, the phenomenon of agglomeration, segregation and even hardening of a nano mixture is very easy to generate in the drying process, the adverse effect is caused on a nitridation reaction, and when the powder is applied after sintering, the dielectric loss is generally large, and the requirement of a millimeter wave frequency band on the material is difficult to meet. The research shows that the state of the precursor directly has great influence on the dielectric property of the aluminum nitride, so that the reasonable control of the state of the precursor is particularly important for improving the dielectric property of the aluminum nitride. Chinese patent application publication No. CN 108793102a discloses a process for preparing aluminum nitride, which utilizes spray drying equipment to dry, and due to huge centrifugal force, the uniform state of aluminum source and carbon source is easily damaged, and component segregation is generated, which adversely affects the nitridation reaction. Chinese patent application publication No. CN 109346678A discloses a forced air drying and vacuum drying process, which can reduce agglomeration of a slurry precursor in the drying process to a certain extent, but the process utilizes a high-temperature and low-pressure drying process, and after the pressure is reduced, the surface tension of a solvent is increased, and the performance of the precursor is also affected to a certain extent.

Disclosure of Invention

The invention mainly aims to provide aluminum nitride ceramic powder, a preparation method thereof and a packaging substrate, and aims to solve the problem that the dielectric property of the aluminum nitride ceramic powder in the prior art cannot meet the 5G requirement.

In order to achieve the above object, according to one aspect of the present invention, there is provided an aluminum nitride ceramic powder having a dielectric constant of 7.8 to 9.0 in a range of 20 to 70 GHz.

Further, the dielectric loss tangent of the aluminum nitride ceramic powder is 0.002 to 0.008 within a range of 20 to 70 GHz.

According to another aspect of the present invention, there is provided a method for preparing aluminum nitride ceramic powder, comprising: step S1, carrying out wet ball milling and mixing on an aluminum source, a carbon source and a solvent to form a wet mixture; step S2, drying the wet mixture in a high-pressure fluid atmosphere to obtain a precursor; step S3, nitriding the precursor to obtain a semi-finished product containing aluminum nitride and an excessive carbon source; and step S4, performing decarbonization treatment on the semi-finished product to obtain aluminum nitride ceramic powder.

Further, the step S2 includes: placing the wet mixture in a drying chamber, heating the wet mixture, and introducing gas into the drying chamber to increase the pressure of the drying chamber, wherein the gas is inert gas or nitrogen, and a gas outlet is arranged above the wet mixture; heating the wet mixture to a predetermined temperature, and releasing pressure when the pressure in the drying chamber is greater than a predetermined pressure so as to maintain the pressure in the drying chamber at the predetermined pressure; and when the gas introduction is stopped, the pressure in the closed drying chamber does not rise any more to indicate that the drying is finished, and the precursor is obtained.

Further, the predetermined pressure is 1.0 to 4.0MPa, preferably 1.2 to 2.0MPa, and the predetermined temperature is 100 to 250 ℃, preferably 150 to 200 ℃.

Further, the flow rate of the gas is 5 to 100L/min, preferably 15 to 20L/min.

Further, in the step S2, the wet mixture is stirred, preferably at a stirring speed of 20 to 200 rpm.

Further, the solvent is water or an organic solvent, and preferably the organic solvent is ethanol, ethylene glycol or propanol.

Further, the step S3 includes: and reacting the precursor for 2-10 h at 1400-1600 ℃ in a nitriding atmosphere to obtain a semi-finished product, wherein the preferable nitriding atmosphere is nitrogen, or a mixed gas of nitrogen and hydrogen, or a mixed gas of nitrogen and ammonia.

Further, the step S4 includes: and (3) keeping the semi-finished product at 550-700 ℃ for 2-6 h in air or oxygen-containing mixed gas for decarbonization to obtain the aluminum nitride ceramic powder.

According to another aspect of the present invention, there is provided an aluminum nitride ceramic powder prepared by any one of the above-mentioned preparation methods.

According to another aspect of the present invention, there is provided a package substrate, wherein the package substrate includes an aluminum nitride ceramic powder, and the aluminum nitride ceramic powder is any one of the aluminum nitride ceramic powders.

By applying the technical scheme provided by the invention, the dielectric constant of the aluminum nitride ceramic powder is 7.8-9.0 within the range of 20-70 GHz. Based on the dielectric property, the aluminum nitride ceramic powder can be used for a 5G communication consumer electronic chip packaging ceramic substrate or a glass ceramic co-fired substrate.

According to the preparation method, the wet mixture is dried in the high-pressure fluid atmosphere, the temperature and pressure control in the drying process is realized, the solvent in the wet mixture is gasified after being heated and is discharged along with the high-pressure fluid, and the drying of the precursor is realized. The step can effectively avoid the occurrence of segregation, agglomeration or hardening in the drying process of the precursor of the nano mixture, and obtain the precursor with better performance; the dielectric constant and dielectric loss of the aluminum nitride ceramic powder obtained after nitridation reaction and decarbonization are obviously improved, and the aluminum nitride ceramic powder can be applied to the application fields of 5G communication consumer electronic chip packaging ceramic substrates, glass ceramic co-fired substrates and the like.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 shows a schematic structural view of a drying apparatus employed according to example 1 of the present invention.

Wherein the figures include the following reference numerals:

1. a drying chamber; 2. a stirring paddle; 3. a heater.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

As analyzed by the background art of the application, the dielectric property of the aluminum nitride ceramic powder in the prior art can not meet the 5G requirement. In order to solve the problem, the application provides aluminum nitride ceramic powder, a preparation method thereof and a packaging substrate.

In one exemplary embodiment of the present disclosure, an aluminum nitride ceramic powder is provided, wherein the aluminum nitride ceramic powder has a dielectric constant of 7.8 to 9.0, preferably 7.9 to 9.0, in a range of 20 to 70 GHz. Based on the dielectric property, the aluminum nitride ceramic powder can be used for a 5G communication consumer electronic chip packaging ceramic substrate or a glass ceramic co-fired substrate.

The dielectric loss tangent of the aluminum nitride ceramic powder is preferably 0.002-0.008, and more preferably 0.04-0.08 in the range of 20-70 GHz.

Through research, it is found that the dielectric property of the aluminum nitride ceramic powder in the prior art cannot meet the use requirement of 5G because the aluminum nitride ceramic powder is prepared by using a mixture of an aluminum source and a carbon source and is easy to agglomerate and segregate when being dried, and in order to solve the problem, in another exemplary embodiment of the present application, a method for preparing the aluminum nitride ceramic powder is provided, which includes: step S1, carrying out wet ball milling and mixing on an aluminum source, a carbon source and a solvent to form a wet mixture; step S2, drying the wet mixture in a high-pressure fluid atmosphere to obtain a precursor; step S3, nitriding the precursor to obtain a semi-finished product containing aluminum nitride and an excessive carbon source; and step S4, performing decarbonization treatment on the semi-finished product to obtain aluminum nitride ceramic powder.

According to the preparation method, the wet mixture is dried in the high-pressure fluid atmosphere, the temperature and pressure control in the drying process is realized, the solvent in the wet mixture is gasified after being heated and is discharged along with the high-pressure fluid, and the drying of the precursor is realized. The step can effectively avoid the occurrence of segregation, agglomeration or hardening in the drying process of the precursor of the nano mixture, and obtain the precursor with better performance; the dielectric constant and dielectric loss of the aluminum nitride ceramic powder obtained after nitridation reaction and decarbonization are obviously improved, and the aluminum nitride ceramic powder can be applied to the application fields of 5G communication consumer electronic chip packaging ceramic substrates, glass ceramic co-fired substrates and the like.

In an embodiment of the present application, the step S2 includes: placing the wet mixture in a drying chamber, heating the wet mixture, and introducing gas into the drying chamber to increase the pressure of the drying chamber, wherein the gas is inert gas or nitrogen, and a gas outlet is arranged above the wet mixture; heating the wet mixture to a predetermined temperature, and releasing pressure when the pressure in the drying chamber is greater than a predetermined pressure so as to maintain the pressure in the drying chamber at the predetermined pressure; and when the gas introduction is stopped, the pressure in the closed drying chamber does not rise any more to indicate that the drying is finished, and the precursor is obtained.

In the process, the solvent in the wet mixture is volatilized by heating, and the volatilized solvent flows out along with the introduced gas by pressure relief so as to realize the purpose of drying the solvent. After the gas is stopped to be introduced, under the condition that the temperature is not changed, the pressure in the closed drying chamber does not rise any more, which indicates that the solvent is not volatilized any more, and further indicates that the drying is finished. The pressure in the drying chamber can be monitored in real time by adopting the pressure detector, the pressure detector is electrically connected with the valve of the gas outlet, and when the pressure detector detects that the pressure in the drying chamber is greater than the preset pressure, an open instruction is sent to the valve of the gas outlet to release the pressure so as to maintain the pressure in the drying chamber at the preset pressure. The temperature of the wet mixture can be monitored through a temperature detector so as to realize accurate control of the temperature, the temperature detector is electrically connected with the heater, when the temperature detector detects that the temperature of the wet mixture exceeds a preset temperature, a heating stopping instruction is sent to the heater, and the heater stops heating after receiving the instruction so as to avoid over-temperature.

The predetermined temperature in the above process can be increased appropriately with reference to the drying temperature commonly used in the prior art to increase the volatilization speed of the solvent under high pressure, and in a preferred embodiment, the predetermined pressure is 1.0 to 4.0MPa, preferably 1.2 to 2.0MPa, and the predetermined temperature is 100 to 250 ℃, preferably 150 to 200 ℃.

On the premise of considering both drying efficiency and drying effect, the flow speed of the gas is preferably 5-100L/min, and preferably 15-20L/min, so that drying can be completed in a short time as far as possible, and agglomeration, segregation or hardening can be avoided as far as possible.

In order to further improve the drying efficiency, it is preferable to stir the wet mixture during the process of step S2. The stirring speed is more preferably 20rpm to 200 rpm.

The above step S2 of the present application has the aforementioned effect on the wet mixture formed by the current wet ball milling mixing, wherein the solvent used in the wet ball milling can be water or an organic solvent, and preferably, the organic solvent is ethanol, ethylene glycol or propanol. The conditions of the wet ball milling and the usage of the aluminum source, the carbon source and the solvent can be referred to the prior art, and are not described herein again.

In one embodiment, the step S3 includes: and reacting the precursor for 2-10 h at 1400-1600 ℃ in a nitriding atmosphere to obtain a semi-finished product, wherein the preferable nitriding atmosphere is nitrogen, or a mixed gas of nitrogen and hydrogen, or a mixed gas of nitrogen and ammonia. In order to achieve as thorough a nitriding of the aluminium source as possible.

The method for removing carbon from the semi-finished product obtained in the present application may also refer to the prior art, such as burning off in an oxygen-containing atmosphere or calcining off carbon in a carbon dioxide atmosphere, and in order to improve the carbon removal efficiency, the step S4 preferably includes: and (3) keeping the semi-finished product at 550-700 ℃ for 2-6 h in air or oxygen-containing mixed gas for decarbonization to obtain aluminum nitride powder.

In another exemplary embodiment of the present application, there is provided an aluminum nitride ceramic powder prepared by any one of the above-mentioned preparation methods. The dielectric constant and the dielectric loss of the aluminum nitride ceramic powder obtained by the preparation method are improved to some extent, and the dielectric constant is 7.8-9.0 and the dielectric loss tangent is 0.002-0.008 within the range of 20-70GHz through tests. Based on the dielectric property, the aluminum nitride ceramic powder can be used for a 5G communication consumer electronic chip packaging ceramic substrate or a glass ceramic co-fired substrate.

In another exemplary embodiment of the present application, a package substrate is provided, which includes the aluminum nitride ceramic powder described above. The packaging substrate can be a ceramic substrate or a glass ceramic co-fired substrate for packaging 5G communication consumer electronic chips.

The advantageous effects of the present application will be further described below with reference to examples and comparative examples.