保定市氮化铝厂

氮化铝陶瓷基板的金属化工艺

Metallization process of AlN ceramic substrate

薄膜法

Membrane method

薄膜法是采取离子镀、真空蒸镀、溅射镀膜等方法在氮化铝陶瓷基板上制备金属薄膜。理论上任何金属薄膜都可以通过气相沉积技术镀在任何基板材料上，但是为了获得粘结强度更好的基板/金属膜层系统，一般要求两者的热膨胀系数应尽量匹配。通常在多层结构基板中，基板内部金属和表层金属不尽相同，陶瓷基板相接触的薄膜金属应该具有反应性好、与基板结合力强的特性，表面金属层多选择电导率高、不易氧化的金属。

Thin film method is to prepare metal film on AlN ceramic substrate by ion plating, vacuum evaporation and sputtering. Theoretically, any metal film can be deposited on any substrate material by vapor deposition technology. However, in order to obtain a substrate / metal film system with better bonding strength, the thermal expansion coefficient of the two materials should be matched as much as possible. Generally, in the multilayer structure substrate, the inner metal and the surface metal are not the same. The film metal in contact with the ceramic substrate should have the characteristics of good reactivity and strong adhesion with the substrate. The surface metal layer should choose the metal with high conductivity and not easy to oxidize.

薄膜法金属化层均匀，金属化层质量高，结合强度高，但是设备投资大，难以进行规模化生产。

The metallization layer of thin film method is uniform, the quality of metallization layer is high, and the bonding strength is high, but the equipment investment is large, so it is difficult to carry out large-scale production.

厚膜法

Thick film method

厚膜金属化法是在氮化铝陶瓷基板上通过丝网印刷等技术在陶瓷表面按预先设计好的样式覆盖上一层厚膜浆料，经烧结得到可以满足不同需求的钎焊金属层、电路及引线接电等。厚膜浆料一般包括永久粘结剂、有机载体和金属粉末，经球磨混炼而成，粘结剂一般是玻璃料或金属氧化物或是二者的混合物，其作用是连结陶瓷与金属并决定着厚膜浆料对基体陶瓷的附着力，是厚膜浆料制作的关键。有机载体的作用主要是分散功能相和粘结相，同时使厚膜浆料保持一定的粘度，为后续的丝网印刷做准备，在烧结过程中会逐渐挥发。金属粉末是厚膜浆料中的核心物质，在经过热处理后在陶瓷表面形成金属层，从而实现陶瓷的表面金属化。

Thick film metallization method is to cover the ceramic surface with a layer of thick film slurry on the ceramic surface by screen printing and other technologies on aluminum nitride ceramic substrate. After sintering, brazing metal layer, circuit and lead wire connection can meet different requirements. Thick film slurry generally includes permanent binder, organic carrier and metal powder, which is made by ball milling. The binder is usually glass or metal oxide or a mixture of them. Its function is to connect ceramic and metal and determine the adhesion of thick film slurry to matrix ceramics, which is the key to the production of thick film slurry. The main function of organic carrier is to disperse the functional phase and the adhesive phase, and keep the thick film slurry with a certain viscosity, which is prepared for the subsequent screen printing, and will gradually volatilize in the sintering process. Metal powder is the core material in thick film slurry. After heat treatment, a metal layer is formed on the surface of ceramic to realize the surface metallization of ceramic.

由于氮化铝的活泼性强，所以不能套用已经较为成熟的陶瓷厚膜金属化使用的浆料，否则会导致产生气泡缺陷。厚膜法工艺简单，方便小批量化生产，且导电性能好，但结合强度不够高，且受温度影响大。

Due to the high activity of AlN, the slurry used for metallization of ceramic thick film can not be applied, otherwise bubble defects will be produced. Thick film process is simple, convenient for small batch production, and good conductivity, but the bonding strength is not high enough, and it is greatly affected by temperature.

高熔点金属化法

High melting point metallization

高熔点金属法也称为Mo-Mn法，是以难熔金属粉Mo为主，再加入少量低熔点Mn的金属化配方，加入粘结剂涂覆到陶瓷表面，然后烧结形成金属化层。这个方法主要应用在Al2O3的金属化中，如要在AlN表面使用该方法则需要在AlN陶瓷表面预先氧化处理上一层Al2O3，以便于与金属粉末反应。

The high melting point metal method, also known as Mo Mn method, is mainly composed of refractory metal powder Mo, and then a small amount of low melting point Mn is added. The binder is added to coat the ceramic surface, and then sintered to form a metallized layer. This method is mainly used in the metallization of Al2O3. If the method is to be used on the surface of AlN, a layer of Al2O3 should be pre oxidized on the surface of AlN Ceramics to react with metal powder.

高熔点金属化法制备得到的金属覆盖层与陶瓷基体结合力较强，但获得的金属膜表面直接焊接比较困难，且导电性不理想，耗能大。

The metal coating prepared by high melting point metallization has strong bonding force with ceramic substrate, but it is difficult to weld the metal film surface directly, and the conductivity is not ideal and the energy consumption is large.

直接覆铜法

Direct copper coating method

直接覆铜法是在AlN陶瓷表面键合铜箔的一种金属化方法，它是随着板上芯片封装技术的兴起而发展出来的一种新型工艺。其基本原理是在Cu与陶瓷之间引进氧元素，然后在1065~1083℃时形成Cu/O共晶液相，进而与陶瓷基体及铜箔发生反应生成Cu(AlO2)2，并在中间相的作用下实现铜箔与基体的键合。因 AlN属于非氧化物陶瓷，其表面敷铜的关键在于在其表面形成一层Al2O3过渡层，并在过渡层的作用下实现铜箔与基体陶瓷的有效键合。

Direct copper coating is a metallization method for bonding copper foil on AlN ceramic surface. It is a new technology developed with the rise of chip on board packaging technology. The basic principle is that oxygen is introduced between Cu and ceramic, and then Cu / O eutectic liquid phase is formed at 1065 ~ 1083 ℃, which reacts with ceramic matrix and copper foil to form Cu (AlO2) 2, and realizes the bonding between copper foil and matrix under the action of intermediate phase. Because AlN belongs to non oxide ceramics, the key to copper coating on the surface of AlN is to form a layer of Al2O3 transition layer on the surface of AlN, and realize the effective bonding between copper foil and matrix ceramics under the action of the transition layer.

直接覆铜法导热性好，附着强度高，机械性能好，易于大规模生产，但氧化工艺条件不易控制。

The direct copper coating method has good thermal conductivity, high adhesion strength and good mechanical properties. It is easy to produce in large scale, but the oxidation process conditions are not easy to control.

化学镀法

Electroless plating

化学镀法是利用还原剂将溶液中的金属离子还原在催化活性的物体表面而形成金属镀层。化学镀法基体表面的粗糙度对镀层的粘附强度有很大的影响，并且在一定范围内，结合强度随着基片表面的粗糙度增大而提高。因此化学镀法的关键工艺是对AlN陶瓷进行表面粗糙化处理。

Electroless plating is the use of reducing agent to reduce the metal ions in the solution on the surface of the catalytic active object to form a metal coating. The surface roughness of electroless plating has a great influence on the adhesion strength of the coating, and in a certain range, the bonding strength increases with the increase of substrate surface roughness. Therefore, the key process of electroless plating is to roughen the surface of AlN Ceramics.

化学镀法成本较低，适应于大规模生产，但是结合强度较低，特别是在高温环境下的结合强度特别低，所以只适用于那些对结合强度要求不是很高的行业。

The cost of electroless plating is low, and it is suitable for large-scale production, but the bonding strength is low, especially in high-temperature environment, so it is only suitable for those industries where the requirement of bonding strength is not very high.