阅读说明：本技术 一种氮化铝基板用包封浆料及其制备方法和应用 (Encapsulation slurry for aluminum nitride substrate and preparation method and application thereof ) 是由 刘飘 宁天翔 宁文敏 于 2019-09-25 设计创作，主要内容包括：本发明提供了一种氮化铝基板用包封浆料,包括：65～80wt％的玻璃粉；0～10wt％的无机添加剂；10～35wt％的有机载体；所述玻璃粉由包括以下物料的原料制备得到：50～75wt％的ZnO；1～15wt％的SiO<Sub>2</Sub>；0～3wt％的Al<Sub>2</Sub>O<Sub>3</Sub>；7～45wt％的H<Sub>3</Sub>BO<Sub>3</Sub>。本发明提供的氮化铝基板用包封浆料与氮化铝基材膨胀系数完美匹配,烧结后表面光滑,平整,结合力好,同时不含铅铬汞等有毒元素,特别是该包封介质浆料烧结在氮化铝基片表面的电路上后,电阻层的烧结前后的阻值变化率小于±5％。本发明还提供了一种氮化铝基板用包封浆料的制备方法和应用。(The invention provides an encapsulation slurry for an aluminum nitride substrate, which comprises the following components: 65-80 wt% of glass powder; 0-10 wt% of an inorganic additive; 10-35 wt% of an organic vehicle; the glass powder is prepared from the following raw materials: 50-75 wt% of ZnO; 1 to 15 wt% of SiO 2 (ii) a 0 to 3 wt% of Al 2 O 3 (ii) a 7 to 45 wt% of H 3 BO 3 . The encapsulation slurry for the aluminum nitride substrate is perfectly matched with the expansion coefficient of the aluminum nitride substrate, the surface is smooth and flat after sintering, the bonding force is good, and toxic elements such as lead, chromium, mercury and the like are not contained, and particularly after the encapsulation medium slurry is sintered on a circuit on the surface of the aluminum nitride substrate, the resistance value change rate of a resistance layer before and after sintering is less than +/-5%. The invention also provides a preparation method and application of the encapsulation slurry for the aluminum nitride substrate.)

1. An encapsulating paste for an aluminum nitride substrate, comprising:

65-80 wt% of glass powder;

0-10 wt% of an inorganic additive;

10-35 wt% of an organic vehicle;

the glass powder is prepared from the following raw materials:

50-75 wt% of ZnO;

1 to 15 wt% of SiO₂；

0 to 3 wt% of Al₂O₃；

7 to 45 wt% of H₃BO₃。

2. The encapsulating paste for the aluminum nitride substrate according to claim 1, wherein the glass frit has a particle size of 1 to 3.5 μm.

3. The encapsulation paste for the aluminum nitride substrate according to claim 1, wherein the inorganic additive is selected from ZnO and B₂O₃AlN and Y₂O₃One or more of them.

4. The encapsulating paste for the aluminum nitride substrate according to claim 1, wherein the organic vehicle comprises:

40-70 wt% of an organic solvent;

1-40 wt% of an organic resin;

5 to 23 wt% of an organic additive.

5. An encapsulation paste for an aluminum nitride substrate according to claim 4, wherein the organic solvent is one or more selected from terpineol, butyl carbitol, alcohol ester dodeca, butyl carbitol acetate and tributyl citrate.

6. An encapsulation paste for an aluminum nitride substrate according to claim 4, wherein the organic resin is one or more selected from the group consisting of ethyl cellulose, cellulose acetate butyrate, acrylic resin, and polyvinyl butyral.

7. The encapsulation paste for the aluminum nitride substrate according to claim 4, wherein the organic additive is selected from one or more of hydrogenated castor oil, TDO, span 85, Tego656 and a thixotropic agent PLUS.

8. A method for preparing the encapsulating paste for the aluminum nitride substrate according to claim 1, comprising:

and mixing the glass powder, the inorganic additive and the organic carrier to obtain the encapsulation slurry for the aluminum nitride substrate.

9. The method of claim 8, wherein the method of preparing the glass frit comprises:

ZnO and SiO₂、Al₂O₃And H₃BO₃Directly carrying out high-temperature treatment to obtain a molten liquid without preheating or slowly raising the temperature after mixing, wherein the temperature of the high-temperature treatment is 1000-1400 ℃;

performing water quenching on the molten liquid in water to obtain glass slag;

and grinding the glass slag to obtain glass powder.

10. Use of the encapsulating slurry for aluminum nitride substrates according to claim 1 as an encapsulating slurry for aluminum nitride substrates.

Technical Field

The invention relates to the technical field of slurry, in particular to encapsulation slurry for an aluminum nitride substrate and a preparation method and application thereof.

Background

The aluminum nitride substrate high-power chip component is mainly applied to the fields of military radio frequency antennas, aerospace, radars, mobile phones, 5G communication equipment, automobile electronics and the like, the global sales volume is more than 1000 hundred million each month at present, and the annual growth rate reaches more than 20%.

At present, the encapsulation medium slurry of the major manufacturers of the aluminum nitride substrate high-power chip components in China mainly depends on import, mainly in the United states and Japan, and no slurry manufacturers in China develop the encapsulation medium slurry for the aluminum nitride substrate, which seriously restricts the development of the industry of the aluminum nitride substrate high-power chip components, so that the development of the encapsulation medium slurry for the aluminum nitride substrate high-power chip components is urgent and necessary.

The aluminum nitride substrate high-power chip component adopts aluminum nitride as a substrate material, and because the aluminum nitride substrate material has small expansion coefficient and high thermal conductivity, the expansion coefficient of the encapsulating medium slurry for the surface circuit of the aluminum nitride substrate high-power chip component is required to be close to that of the aluminum nitride so as to be well matched, while the existing encapsulating medium slurry is mainly used for an alumina substrate chip resistor and cannot meet the application requirement that the re-burning change rate of the aluminum nitride substrate high-power chip component is less than +/-5%.

Therefore, it is necessary to develop an encapsulating medium slurry which has low cost, is matched with the expansion coefficient of the aluminum nitride substrate, and has a change rate of less than +/-5% before and after the resistance coverage on the chip component.

Disclosure of Invention

In view of the above, the present invention provides an encapsulation slurry for an aluminum nitride substrate, and a preparation method and an application thereof.

The invention provides an encapsulation slurry for an aluminum nitride substrate, which comprises the following components:

65-80 wt% of glass powder;

0-10 wt% of an inorganic additive;

10 to 35 wt% of an organic vehicle.

In the invention, the mass content of the glass powder is preferably 70-75%; the mass content of the inorganic additive is preferably 1-8%, more preferably 2-6%, and most preferably 3-5%; the mass content of the organic carrier is preferably 15-30%, and more preferably 20-25%.

In the invention, the glass powder is prepared from the following raw materials:

50-75 wt% of ZnO;

1 to 15 wt% of SiO₂；

0 to 3 wt% of Al₂O₃；

7 to 45 wt% of H₃BO₃。

In the invention, the mass content of ZnO is preferably 55-70%, and more preferably 60-70%; the SiO₂The mass content of (b) is preferably 5-10%, more preferably 6-8%; the Al is₂O₃The mass content of (b) is preferably 0.5 to 2.5%, more preferably 1 to 2%, most preferably 1.5%; said H₃BO₃The content of (b) is preferably 10 to 40% by mass, more preferably 20 to 30% by mass, and most preferably 25% by mass.

In the present invention, the method for preparing the glass frit preferably includes:

ZnO and SiO₂、Al₂O₃And H₃BO₃Directly carrying out high-temperature treatment without preheating or slowly raising the temperature after mixing to obtain molten liquid;

performing water quenching on the molten liquid in water to obtain glass slag;

and grinding the glass slag to obtain glass powder.

In the invention, the ZnO and the SiO₂、Al₂O₃And H₃BO₃The dosage proportion of the glass powder is consistent with the mass content of each component in the raw materials for preparing the glass powder in the technical scheme, and the details are not repeated herein.

In the present invention, the high-temperature treatment is preferably carried out in a corundum crucible; the temperature of the high-temperature treatment is preferably 1000-1400 ℃, more preferably 1100-1300 ℃, and most preferably 1200 ℃; the heat preservation time of the high-temperature treatment is preferably 10-60 min, more preferably 20-50 min, and most preferably 30-40 min. In the present invention, if the high temperature treatment temperature is lower than 1100 ℃, the viscosity of the melt is too high to pour into water for water quenching.

In the present invention, the water is preferably deionized water.

The preparation method of the glass powder is preferably adopted, the inorganic powder is directly put into a high-temperature furnace at the temperature of 1100-1400 ℃ from room temperature for heating for half an hour without preheating or slowly raising the temperature after being mixed, and then water quenching is carried out, so that the obtained encapsulation slurry has better stability of softening temperature control.

In the present invention, the grinding method is preferably ball milling, and more preferably ball milling is performed using a zirconia pot and zirconia balls.

In the present invention, after the grinding, the obtained product is preferably dried and powdered to obtain glass powder.

In the invention, the granularity of the glass powder is preferably 1-3.5 μm, more preferably 1.5-3 μm, and most preferably 2-2.5 μm.

In the present invention, the inorganic additive is preferably selected from ZnO, B₂O₃AlN and Y₂O₃One or more of the above; the inorganic additive is preferably a nano inorganic additive; the average particle size range of the nano inorganic additive is preferably 10-500 nm, more preferably 50-300 nm, and most preferably 50-200 nm.

The invention preferably adopts the inorganic additives with the components, and the additives with the components can ensure that the prepared encapsulation slurry has small influence on the resistance, and the slurry after encapsulation has less bubbles, so that the bonding strength of the slurry and the aluminum nitride substrate is high.

In the present invention, the organic vehicle preferably includes:

40-70 wt% of an organic solvent;

1-40 wt% of an organic resin;

5 to 23 wt% of an organic additive.

In the invention, the mass content of the organic solvent is preferably 45-65%, more preferably 50-60%, and most preferably 55%; the mass content of the organic resin is preferably 5-35%, more preferably 10-30%, and most preferably 15-25%; the mass content of the organic additive is preferably 10-20%, and more preferably 15%.

In the present invention, the organic solvent is preferably selected from one or more of alcohols and esters, and more preferably selected from one or more of terpineol, butyl carbitol, alcohol ester dodeca, butyl carbitol acetate and tributyl citrate.

In the present invention, the organic resin is preferably one or more selected from the group consisting of ethyl cellulose, CAB (cellulose acetate butyrate), acrylic resin, and PVB (polyvinyl butyral) resin.

In the present invention, the organic additive is preferably selected from one or more of hydrogenated castor oil, TDO (tallow diamine dioleate), span 85, Tego656 and thixotropic agent PLUS; the organic additive preferably contains a thixotropic agent PLUS.

The invention preferably adopts the organic additive with the components, and the addition of the organic additive not only solves the leveling problem of the slurry, but also introduces the thixotropic agent PLUS, so that the technical problem that the edge of the slurry is thicker than the middle of the slurry due to too good leveling after the slurry is printed is solved, the surface of the whole encapsulated medium slurry is smooth after sintering, the thickness is uniform, and the resistance change rate is small, stable and controllable.

In the present invention, the method for preparing the organic vehicle preferably includes:

mixing and dissolving an organic solvent, organic resin and an organic additive to obtain the organic carrier.

In the present invention, the dosage ratio of the organic solvent, the organic resin and the organic additive is consistent with the mass content of each component in the organic vehicle in the above technical scheme, and details are not repeated herein.

In the invention, the mixing and dissolving temperature is preferably 50-90 ℃, more preferably 60-80 ℃, and most preferably 70 ℃.

The invention adopts ZnO and SiO₂、Al₂O₃、H₃BO₃Is used as a raw material and is smelted at the high temperature of 1000-1400 ℃ to prepare ZnO-SiO₂-Al₂O₃-B₂O₃Glass, and nano ZnO, AlN and B are added₂O₃And Y₂O₃As an inorganic additive; finally, the encapsulating medium slurry for the high-power chip element with the aluminum nitride substrate, which is low in cost and small in resistance change rate after being covered, is prepared.

The invention provides a preparation method of the encapsulation slurry for the aluminum nitride substrate, which comprises the following steps:

and mixing the glass powder, the inorganic additive and the organic carrier to obtain the encapsulation slurry for the aluminum nitride substrate.

In the present invention, the types and the amounts of the glass powder, the inorganic additive and the organic carrier are the same as those of the components and the mass content in the encapsulation slurry according to the above technical solution, and are not described herein again.

In the present invention, the mixing is preferably performed under stirring, and the stirring is preferably performed by planetary power mixing.

In the present invention, after the mixing is completed, the resulting mixture is preferably ground to be sufficiently and uniformly dispersed; the grinding is preferably carried out using a three-roll mill.

In the present invention, the encapsulation paste is preferably a uniformly dispersed paste having good rheological properties.

The invention provides an application of the encapsulation slurry for the aluminum nitride substrate in the technical scheme as the encapsulation slurry for the aluminum nitride substrate, and more preferably an application of the encapsulation slurry for a high-power chip component of the aluminum nitride substrate. In the present invention, the specific method of the application preferably includes:

and printing the aluminum nitride substrate on the surface of the aluminum nitride substrate by using an encapsulation slurry, and then drying and sintering the aluminum nitride substrate in sequence to encapsulate the aluminum nitride substrate by the slurry.

In the present invention, the method of printing is preferably screen printing; the printing thickness is preferably 10-20 μm.

The invention has no special limitation on the type and source of the aluminum nitride substrate, and a person skilled in the art can select a suitable aluminum nitride substrate according to actual needs, wherein the thermal conductivity of the aluminum nitride substrate is preferably 170-220W/m.K; the thickness of the aluminum nitride substrate is preferably 0.2-2 mm; can be purchased from the market.

In the present invention, the surface of the aluminum nitride substrate is preferably provided with a resistance coating layer, the resistance coating layer is preferably formed by printing a resistance paste on the surface of the aluminum nitride substrate, and the resistance paste preferably comprises the following components: Ag/Pd resistance paste, RuO resistance paste or ruthenate resistance paste; the thickness of the resistance coating is preferably 8-15 mu m; the temperature of the printing and firing is preferably 830-870 ℃, more preferably 840-860 ℃, and most preferably 850 ℃.

In the invention, the drying temperature is preferably 140-160 ℃, more preferably 145-155 ℃, and most preferably 150 ℃; the drying time is preferably 8-12 min, and more preferably 10 min.

In the invention, the sintering temperature is preferably 640-660 ℃, more preferably 645-655 ℃, and most preferably 650 ℃; the sintering method is preferably as follows:

and sintering the dried product in a belt type sintering furnace at the speed of 300-350 mm/min for 3-5 min.

The existing encapsulating medium slurry is mainly applied to an alumina substrate sheet element, and because the expansion coefficient of an aluminum nitride substrate is small and is far smaller than that of the alumina substrate, the existing encapsulating medium slurry and the aluminum nitride substrate have the problems of unmatched expansion coefficients, so that the bonding force is poor, the surface is foamed, the existing encapsulating medium slurry is not smooth and flat, and the encapsulating insulation effect cannot be achieved, meanwhile, the existing encapsulating medium slurry is incompatible with a resistance layer on the aluminum nitride substrate, the change rate of the resistance before and after covering is large, and the application requirement that the change rate before and after covering is smaller than +/-5% cannot be met.

The encapsulation slurry provided by the invention is perfectly matched with the expansion coefficient of the aluminum nitride substrate, the surface is smooth and flat after sintering, the bonding force is good, and meanwhile, toxic elements such as lead, chromium, mercury and the like are not contained, and particularly, after the encapsulation medium slurry is sintered on a circuit on the surface of the aluminum nitride substrate, the resistance value change rate before and after the resistance layer is sintered is less than +/-5%.

Compared with the prior art, the encapsulating medium slurry for the aluminum nitride substrate high-power chip component has perfect expansion coefficient matching with the aluminum nitride substrate, good bonding force, smooth and flat surface and no air bubbles, and particularly, the resistance change rate is less than +/-5 percent before and after the high-square resistance layer covers the encapsulating medium slurry.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other examples, which may be modified or appreciated by those of ordinary skill in the art based on the examples given herein, are intended to be within the scope of the present invention.

All raw materials used in the following examples of the invention are commercially available products, acrylic resin is a KC-40 model product provided by Ruiz electronic materials Co., Ltd, in Dongguan, Tego656 is a Tego656 model product provided by Digao, and PLUS is a PLUS model product provided by Hamming.