阅读说明：本技术 氮化铝陶瓷基板上围坝的共晶焊接方法 (Eutectic welding method for box dam on aluminum nitride ceramic substrate ) 是由 周孔礼 于 2020-05-14 设计创作，主要内容包括：本发明公开了一种氮化铝陶瓷基板上围坝的共晶焊接方法,包括如下步骤：第一步,将氮化铝陶瓷基板通过厚膜印刷技术印刷出金属线路涂层,该金属线路涂层形状与需要焊接到氮化铝陶瓷基板上的围坝的形状适配；第二步,将所述氮化铝陶瓷基板和所述围坝放入到共晶焊接装置中；第三步,在所述氮化铝陶瓷基板的金属线路涂层上放置合金焊料,再将所述围坝隔着所述合金焊料印刷或放置到所述氮化铝陶瓷基板上,所述围坝与所述金属线路涂层的形状对应；第四步,启动所述共晶焊接装置进行焊接,且焊接的温度为150℃-500℃；第五步,焊接完成。本发明针对氮化铝陶瓷的围坝焊接采用共晶焊接的方式进行焊接,相对于现有技术中采用磁控溅射,更加方便操作,成本更低。(The invention discloses an eutectic welding method of an upper box dam of an aluminum nitride ceramic substrate, which comprises the following steps: firstly, printing a metal circuit coating on an aluminum nitride ceramic substrate by a thick film printing technology, wherein the shape of the metal circuit coating is matched with that of a box dam needing to be welded on the aluminum nitride ceramic substrate; secondly, putting the aluminum nitride ceramic substrate and the box dam into a eutectic welding device; thirdly, alloy solder is placed on the metal circuit coating of the aluminum nitride ceramic substrate, and then the dam is printed or placed on the aluminum nitride ceramic substrate through the alloy solder, wherein the shape of the dam corresponds to that of the metal circuit coating; fourthly, starting the eutectic welding device for welding, wherein the welding temperature is 150-500 ℃; and fifthly, completing welding. The aluminum nitride ceramic box dam welding method adopts an eutectic welding mode for welding the aluminum nitride ceramic box dam, and is more convenient to operate and lower in cost compared with the method of adopting magnetron sputtering in the prior art.)

1. An eutectic welding method of an aluminum nitride ceramic substrate upper box dam is characterized by comprising the following steps:

firstly, printing a metal circuit coating on an aluminum nitride ceramic substrate by a thick film printing technology, wherein the shape of the metal circuit coating is matched with that of a box dam needing to be welded on the aluminum nitride ceramic substrate;

secondly, putting the aluminum nitride ceramic substrate and the box dam into a eutectic welding device;

thirdly, alloy solder is placed on the metal circuit coating of the aluminum nitride ceramic substrate, and then the dam is printed or placed on the aluminum nitride ceramic substrate through the alloy solder, wherein the shape of the dam corresponds to that of the metal circuit coating;

fourthly, starting the eutectic welding device for welding, wherein the welding temperature is 150-500 ℃;

and fifthly, completing welding.

2. The eutectic soldering method of a dam on an aluminum nitride ceramic substrate according to claim 1, wherein the thick film printing technique comprises the steps of:

preparing an aluminum nitride ceramic substrate for printing and a metal paste for printing or placement;

secondly, thick film screen printing is carried out on the aluminum nitride ceramic substrate by using the metal paste, and the thickness of a circuit formed by the metal paste is 20-200 mu m;

thirdly, sintering the circuit formed in the last step, and adding mixed gas through a high-temperature tunnel furnace to perform high-temperature sintering at the sintering temperature of 150-1500 ℃;

and fourthly, manufacturing the aluminum nitride ceramic substrate with the metal circuit coating.

3. The eutectic soldering method of the dam on the aluminum nitride ceramic substrate according to claim 2, wherein the dam is made of a ceramic material, and the side of the dam for soldering is first printed with a metal coating by the thick film printing technique.

4. The eutectic bonding method of a dam on an aluminum nitride ceramic substrate according to claim 2 or 3, wherein a vacuum-pumping device is started to vacuumize the bonding environment before bonding in the eutectic bonding device.

Technical Field

The invention relates to the technical field of glass packaging, in particular to an eutectic welding method for a box dam on an aluminum nitride ceramic substrate.

Background

The aluminum nitride material is grey white, belongs to hexagonal system and is [ AlN ]₄]Tetrahedron as structural unitThe wurtzite-type covalent bond compound of (1). The structure determines that the structure has excellent thermal, electrical and mechanical properties. The theoretical thermal conductivity of AlN ceramic can reach 320W/(m.K), and the thermal conductivity of commercial products is generally 180W/(m.K) -260W/(m.K) [9 ]]The thermal expansion coefficient is 4 multiplied by 106/° C in the temperature range of 25 ℃ -200 ℃ (basically matched with semiconductor chip materials such as Si, GaAs and the like), the elastic modulus is 310GPa, the bending strength is 300MPa-340MPa, and the dielectric constant is 8-10.

AlN ceramic sintering also requires sintering aids to improve performance and quality. The common sintering aid is Y₂O₃、CaO、Li₂O、BaO、MgO、SrO、La₂O₃、HfO₂And CeO₂And the like. The main functions of the sintering aid are as follows: firstly, a low-melting-point phase is formed, and liquid-phase sintering is realized, so that the sintering temperature is reduced; secondly, the silicon oxide reacts with impurity oxygen in crystal lattices to complete the crystal lattices, thereby improving the performance of the ceramic. In general, binary or multiple sintering aids tend to achieve better sintering results. The sintering aid is added directly, and the other sintering aid is prepared into a precursor in situ in the form of soluble nitrate. The traditional AlN ceramic forming method comprises die pressing, isostatic pressing, hot pressing and the like, but the methods have long production period, low efficiency and uneven stress of products in all directions and can not meet the electronic packaging requirement. In recent years, processes such as tape casting, injection-coagulation molding, and injection molding have been developed. Among them, the tape casting method is mainly applied to the preparation of sheet products, and is divided into organic and inorganic systems. Relatively, the organic tape casting system has the characteristics of wide solvent selection range, short drying time, prevention of powder hydration and the like, but common organic solvents such as alcohol, ketone, benzene and the like have certain toxicity and the production is limited to a certain extent. Therefore, the water-based tape casting method is mainly adopted in the industry at present, but the problems that the blank is easy to foam and deform after being dried, the sintering is easy to crack, the surface of a product is not smooth and the like exist.

The thermal conductivity of the aluminum nitride ceramic is 6-8 times that of the aluminum oxide ceramic, but the thermal expansion coefficient is only 50%, and the aluminum nitride ceramic also has the advantages of high insulating strength, low dielectric constant, good corrosion resistance and the like. Besides higher cost, the aluminum nitride ceramic has better comprehensive performance than the aluminum oxide ceramic, is an ideal electronic packaging substrate material and is particularly suitable for the field with higher requirement on heat-conducting performance.

When the aluminum nitride ceramic substrate is used as an LED substrate, a box dam needs to be welded, the existing welding is carried out in a magnetron sputtering mode, the operation is relatively complex, and the cost is higher.

Disclosure of Invention

In view of the above problems in the prior art, the present invention provides a eutectic soldering method for an aluminum nitride ceramic substrate upper dam, which comprises the following steps:

an eutectic welding method for an aluminum nitride ceramic substrate upper box dam comprises the following steps:

firstly, printing a metal circuit coating on an aluminum nitride ceramic substrate by a thick film printing technology, wherein the shape of the metal circuit coating is matched with that of a box dam needing to be welded on the aluminum nitride ceramic substrate;

secondly, putting the aluminum nitride ceramic substrate and the box dam into a eutectic welding device;

thirdly, alloy solder is placed on the metal circuit coating of the aluminum nitride ceramic substrate, and then the dam is printed or placed on the aluminum nitride ceramic substrate through the alloy solder, wherein the shape of the dam corresponds to that of the metal circuit coating;

fourthly, starting the eutectic welding device for welding, wherein the welding temperature is 150-500 ℃;

and fifthly, completing welding.

Further preferably, the thick film printing technique comprises the steps of:

preparing an aluminum nitride ceramic substrate for printing and a metal paste for printing or placement;

secondly, thick film screen printing is carried out on the aluminum nitride ceramic substrate by using the metal paste, and the thickness of a circuit formed by the metal paste is 20-200 mu m;

thirdly, sintering the circuit formed in the last step, and adding mixed gas through a high-temperature tunnel furnace to perform high-temperature sintering at the sintering temperature of 150-1500 ℃;

and fourthly, manufacturing the aluminum nitride ceramic substrate with the metal circuit coating.

Further preferably, the dam is made of a ceramic material, and the side of the dam for welding is printed with a metal coating by the thick film printing technology.

Preferably, before welding in the eutectic welding device, a vacuum pumping device is started to perform vacuum treatment on the welding environment.

Has the advantages that: the welding method is novel in concept, reasonable in design and convenient to use, and the aluminum nitride ceramic box dam is welded in an eutectic welding mode, so that compared with the magnetron sputtering method in the prior art, the method is more convenient to operate and lower in cost.

Drawings

Fig. 1 is an exploded view of a specific welding structure according to an embodiment of the present invention.

Detailed Description

The invention is further illustrated by the following examples in conjunction with the accompanying drawings:

referring to fig. 1, a eutectic soldering method for an aluminum nitride ceramic substrate upper dam includes the following steps:

firstly, printing a metal circuit coating 2 on an aluminum nitride ceramic substrate 1 by a thick film printing technology, wherein the shape of the metal circuit coating 2 is matched with that of a box dam 3 needing to be welded on the aluminum nitride ceramic substrate 1;

secondly, putting the aluminum nitride ceramic substrate 1 and the box dam 3 into a eutectic welding device;

thirdly, alloy solder is placed on the metal circuit coating 2 of the aluminum nitride ceramic substrate 1, and then the dam 3 is printed or placed on the aluminum nitride ceramic substrate 1 through the alloy solder, wherein the dam 3 corresponds to the metal circuit coating 2 in shape;

fourthly, starting the eutectic welding device for welding, wherein the welding temperature is 150-500 ℃;

and fifthly, completing welding.

In the basic scheme of the invention, because the aluminum nitride ceramic substrate 1 is made of inorganic materials, in order to realize welding, a metal coating needs to be formed on the surface, and the coating needs to be performed according to a certain rule. Accordingly, the dam 3 needs to be adapted to the pattern formed by the metal coating. Because the eutectic welding is adopted, an eutectic welding device is required, and the welding can be directly carried out under the condition that the box dam is made of metal materials. And placing an alloy coating on the metal line coating 2, placing the aluminum nitride ceramic substrate 1, the alloy coating and the box dam 3, and then starting equipment for welding, wherein the adopted temperature is 150-500 ℃, and is a proper temperature.

Further, preferably, the thick film printing technique comprises the steps of:

a first step of preparing an aluminum nitride ceramic substrate 1 for printing and a metal paste for printing or placement;

secondly, performing thick-film screen printing on the aluminum nitride ceramic substrate 1 by using the metal paste, wherein the thickness of a circuit formed by the metal paste is 20-200 μm;

thirdly, sintering the circuit formed in the last step, and adding mixed gas through a high-temperature tunnel furnace to perform high-temperature sintering at the sintering temperature of 150-1500 ℃;

and fourthly, manufacturing the aluminum nitride ceramic substrate with the metal circuit coating 2.

In the preferred embodiment, a specific method step for thick film printing is provided.

Further, preferably, the dam 3 is made of a ceramic material, and the surface of the dam for welding is printed with a metal coating by the thick film printing technology.

In the preferred embodiment, the dam 3 made of ceramic material is subjected to eutectic soldering by printing a metal coating.

Preferably, the vacuum extractor is started to perform vacuum treatment on the welding environment before welding in the eutectic welding device.

In the preferred scheme, the vacuum pumping treatment is firstly carried out on the welding environment so as to avoid bubbles.

In addition, the method provided by the invention forms the welding between the ceramic substrate and the dam in a eutectic welding mode, and in practical application, the method is not limited to the LED lamp set, and can also be used for other semiconductor packages, such as lasers and the like.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.