阅读说明：本技术 一种氮化铝陶瓷基板表面处理方法 (Surface treatment method for aluminum nitride ceramic substrate ) 是由 王斌 贺贤汉 孙泉 欧阳鹏 葛荘 于 2020-04-28 设计创作，主要内容包括：本发明涉及一种氮化铝陶瓷基板表面处理方法,包括如下工序：1)前处理：去除基板表面的油污和杂质后,将其浸没于有机溶剂液中,处理后取出烘干；2)界面偶联剂处理：将经步骤1)处理后的氮化铝陶瓷基板浸没于界面偶联剂和无水乙醇的混合溶液中常温处理5～10min,而后取出烘干,界面偶联剂和无水乙醇的体积比为1:100～200。本发明中的方法针对陶瓷表面进行化学改性,可改善焊料的附着性,显著提高焊料层与陶瓷表面的化学结合力从而减少焊料结合层的空洞和空隙,提高覆铜板的抗热冲击性能且处理效率高、成本低。且该方法可在对陶瓷表面进行粗化的基础上使用,进一步提高活性金属焊料附着性。(The invention relates to a surface treatment method of an aluminum nitride ceramic substrate, which comprises the following steps: 1) pretreatment: after removing oil stains and impurities on the surface of the substrate, immersing the substrate in organic solvent liquid, taking out and drying the substrate after treatment; 2) interface coupling agent treatment: immersing the aluminum nitride ceramic substrate treated in the step 1) in a mixed solution of an interface coupling agent and absolute ethyl alcohol, treating at normal temperature for 5-10 min, taking out and drying, wherein the volume ratio of the interface coupling agent to the absolute ethyl alcohol is 1: 100-200. The method of the invention carries out chemical modification on the surface of the ceramic, can improve the adhesiveness of the solder, and obviously improves the chemical bonding force between the solder layer and the surface of the ceramic, thereby reducing the cavities and the gaps of the solder bonding layer, improving the thermal shock resistance of the copper-clad plate, and having high treatment efficiency and low cost. The method can be used on the basis of roughening the surface of the ceramic, and the adhesiveness of the active metal solder is further improved.)

1. The surface treatment method of the aluminum nitride ceramic substrate is characterized by comprising the following steps:

1) pretreatment

After removing oil stains and impurities on the surface of the substrate, immersing the substrate in organic solvent liquid, taking out and drying the substrate after treatment;

2) interfacial coupling agent treatment

Immersing the aluminum nitride ceramic substrate treated in the step 1) in a mixed solution of an interface coupling agent and absolute ethyl alcohol, treating at normal temperature for 5-10 min, taking out and drying, wherein the volume ratio of the interface coupling agent to the absolute ethyl alcohol is 1: 100-200.

2. The aluminum nitride ceramic substrate surface treatment method according to claim 1, characterized in that:

the surface of the substrate is coarsened before the step 1) to ensure that the surface roughness reaches 0.3-0.4.

3. The aluminum nitride ceramic substrate surface treatment method according to claim 2, characterized in that:

wherein, the surface roughening treatment mode of the aluminum nitride ceramic substrate comprises the following steps: treating the surface of the aluminum nitride ceramic plate by using an alkaline solution or a mixed acid solution,

the alkaline solution is NaOH or KOH strong base solution with the mass fraction of 15-25%, the mixed acid solution comprises sulfuric acid with the mass fraction of 25-65%, hydrofluoric acid with the mass fraction of 5-8%, and the balance of water.

4. The aluminum nitride ceramic substrate surface treatment method according to claim 1, characterized in that:

wherein in the step 1), oil stain and impurities on the surface of the aluminum nitride ceramic substrate are removed by adopting an oil removing agent and pure water,

the oil removing agent comprises 40-70 g/L of sodium hydroxide, 20-50 g/L of sodium carbonate, 10-20 g/L of trisodium phosphate and the balance of water; the oil removing temperature is set to be 80-90 ℃, the treatment time is 3-5 min, the immersion cleaning time of pure water after oil removing is 1-2 min, and the temperature is 15-25 ℃.

5. The aluminum nitride ceramic substrate surface treatment method according to claim 1, characterized in that:

wherein, in the step 1), the organic solvent is a mixed solution of isopropanol and acetone, and the volume ratio is 3: the specific treatment condition is that the aluminum nitride ceramic substrate is immersed in a mixed solution of isopropanol and acetone, and ultrasonic treatment is carried out for 3-5 min at normal temperature; and during drying, the temperature of the oven is set to be 100 ℃, and the drying time is 5-10 min.

6. The aluminum nitride ceramic substrate surface treatment method according to claim 1, characterized in that:

wherein, in the step 2), the interface coupling agent comprises one or more of organic silicon, titanate and aluminate,

the volume ratio of the organic silicon to the absolute ethyl alcohol is 1:100, the volume ratio of the titanate to the absolute ethyl alcohol is 1:200, and the volume ratio of the aluminate to the absolute ethyl alcohol is 1: 100.

7. The aluminum nitride ceramic substrate surface treatment method according to claim 1, characterized in that:

wherein, the drying conditions in the step 2) are as follows: the temperature of the oven is set to be 100 ℃, and the drying time is 5-10 min.

8. The method for surface treatment of an aluminum nitride ceramic substrate according to claim 1, wherein:

wherein, the aluminum nitride ceramic substrate is an active brazing ceramic substrate.

Technical Field

The invention belongs to the technical field of ceramic substrate surface treatment, and particularly relates to a surface treatment method of an aluminum nitride ceramic substrate.

Background

Aluminum nitride ceramic substrates (ALN) are widely used as liners for power modules of semiconductor devices due to their low dielectric constant, excellent thermal conductivity, and low coefficient of thermal expansion matching the chip. When the active metal brazing technology (AMB) is adopted to realize the metallization of the aluminum nitride ceramic substrate, active metal solder is required to be printed on the surface of the aluminum nitride ceramic plate.

The adhesion of the active metal solder on the surface of the aluminum nitride ceramic plate is one of the important factors for determining the quality of the solder bonding layer of the copper-clad ceramic substrate. In the AMB process, organic matters such as film-forming agents and the like can be added into the active metal solder, and the surface property of the ALN ceramic is greatly different from that of an organic matrix and cannot be directly combined. In order to realize the combination of the two, the surface of the ceramic is roughened by using NaOH solution, mixed acid solution and even plasma bombardment technology at present, and the mechanical embedding force of the metal solder and the ceramic chip is enhanced, so that the problem of poor compatibility of the ceramic and the organic matrix is indirectly solved.

According to the chemical bonding theory, if the surface modifier is coated on the surface of the aluminum nitride ceramic chip, the compatibility between the ceramic chip and the organic substrate can be directly enhanced. Compared with the surface modification treatment method for the surface of the ceramic wafer, the surface modification treatment method has higher efficiency and lower cost, so the development of the surface treatment method for the aluminum nitride ceramic substrate is urgently needed in the technical field of AMB.

Disclosure of Invention

In order to solve the defects of the prior art, the invention provides a surface treatment method of an aluminum nitride ceramic substrate, which comprises two treatment procedures of impurity removal and interface coupling agent treatment, and the direct compatibility between the aluminum nitride ceramic substrate and an organic matrix is enhanced by the treatment method.

In order to achieve the purpose, the invention is implemented by the following technical scheme:

the invention provides a surface treatment method of an aluminum nitride ceramic substrate, which comprises the following steps:

1) pretreatment

After removing oil stains and impurities on the surface of the substrate, immersing the substrate in organic solvent liquid, taking out and drying the substrate after treatment;

2) interfacial coupling agent treatment

Immersing the aluminum nitride ceramic substrate treated in the step 1) in a mixed solution of an interface coupling agent and absolute ethyl alcohol, treating at normal temperature for 5-10 min, taking out and drying, wherein the volume ratio of the interface coupling agent to the absolute ethyl alcohol is 1: 100-200.

Preferably, the treatment method of the present invention can be used in conjunction with a surface roughening treatment step of a ceramic substrate, and roughening treatment is performed to achieve a surface roughness of the ceramic substrate of 0.3 to 0.4 before step 1).

The surface roughening treatment mode of the aluminum nitride ceramic substrate comprises the following steps: treating the surface of the aluminum nitride ceramic plate by using an alkaline solution or a mixed acid solution. The alkaline solution is NaOH or KOH strong base solution with the mass fraction of 15-25%, the mixed acid solution comprises sulfuric acid with the mass fraction of 25-65%, hydrofluoric acid with the mass fraction of 5-8% and the balance of water.

Preferably, in the step 1), oil removing agents and pure water are adopted to remove oil stains and impurities on the surface of the aluminum nitride ceramic substrate. The oil removing agent comprises 40-70 g/L of sodium hydroxide, 20-50 g/L of sodium carbonate, 10-20 g/L of trisodium phosphate and the balance of water; the oil removing temperature is set to be 80-90 ℃, the treatment time is 3-5 min, the immersion cleaning time of pure water after oil removing is 1-2 min, and the temperature is 15-25 ℃.

Preferably, in step 1), the organic solvent is a mixture of isopropanol and acetone, and the volume ratio is 3: the specific treatment condition is that the aluminum nitride ceramic substrate is immersed in a mixed solution of isopropanol and acetone, and ultrasonic treatment is carried out for 3-5 min at normal temperature; and during drying, the temperature of the oven is set to be 100 ℃, and the drying time is 5-10 min. .

Preferably, in step 2), the interface coupling agent comprises one or more of organic silicon, titanate and aluminate. Wherein, the volume ratio of the organic silicon to the absolute ethyl alcohol is 1:100, the volume ratio of the titanate to the absolute ethyl alcohol is 1:200, and the volume ratio of the aluminate to the absolute ethyl alcohol is 1: 100.

The drying conditions are as follows: the temperature of the oven is set to be 100 ℃, and the drying time is 5-10 min, preferably 10 min.

Preferably, the aluminum nitride ceramic substrate in the present invention is an active brazing ceramic substrate.

The invention has the following beneficial effects:

in the method for processing the surface of the aluminum nitride ceramic substrate, the surface of the aluminum nitride ceramic substrate is chemically modified after the aluminum nitride ceramic substrate is processed by the mixed solution of the interface coupling agent and the absolute ethyl alcohol. The interface coupling agent simultaneously has an organophilic group and an inophilic group, the organophilic group is combined with the metal solder layer through a crosslinking curing reaction, and the inophilic group is combined with the ceramic substrate surface through a hydrolytic polycondensation reaction, so that the combination between the metal solder layer and the ceramic substrate surface is realized; the absolute ethyl alcohol is used as a diluent of the interface coupling agent, is easy to volatilize, does not have obvious reaction with the interface coupling agent, and is beneficial to the effect of the interface coupling agent.

Therefore, the method of the invention carries out chemical modification on the ceramic surface, can improve the adhesiveness of the solder, obviously improves the chemical bonding force between the solder layer and the ceramic surface, thereby reducing the cavities and the gaps of the solder bonding layer, improving the thermal shock resistance of the copper-clad plate, and having high treatment efficiency and low cost. The method can be used on the basis of roughening the surface of the ceramic, and the adhesiveness of the active metal solder is further improved.

Drawings

FIG. 1 is a flow chart of the surface treatment of an aluminum nitride ceramic substrate according to the present invention;

FIG. 2 is a simplified schematic diagram of the action mechanism of the interface coupling agent of the present invention, wherein (1) shows that the interface coupling agent realizes the bonding between the active metal solder layer and the AlN ceramic substrate, 1 is a copper foil, 2 is the active metal solder layer, 3 is the interface coupling agent layer, and 4 is the AlN ceramic substrate; (2) the schematic diagram of the action mechanism of the interface coupling agent for realizing the combination between the metal solder layer and the AlN ceramic substrate.

FIG. 3 is a flow chart of the manufacturing process of the aluminum nitride ceramic substrate product of the present invention.

Detailed Description

The following embodiments are implemented on the premise of the technical scheme of the present invention, and give detailed implementation modes and specific operation procedures, but the protection scope of the present invention is not limited to the following embodiments.

The reagents and starting materials used in the present invention are commercially available or can be prepared according to literature procedures. The experimental procedures, in which specific conditions are not noted in the following examples, are generally carried out according to conventional conditions or according to conditions recommended by the manufacturers.