The principle of eutectic welding
Eutectic welding is also called low melting point alloy welding. The basic feature of eutectic alloys is that two different metals can form alloys in a certain weight ratio at temperatures far below their respective melting points. The most commonly used eutectic soldering in microelectronic devices is to solder the chip to the gold-plated base or lead frame, that is, "gold-core eutectic soldering".
The welding process of eutectic welding means that the chip is gently rubbed on the gold-plated base under a certain temperature and a certain pressure, and the unstable oxide layer of the interface is wiped away, so that the contact surface is melted. There are two solid phases. A liquid phase is formed. After cooling, when the temperature is lower than the "gold-core eutectic point", the crystal grains formed by the liquid phase combine with each other into a mechanical mixture, namely: "gold-core eutectic crystal" so that the chip is firmly welded on the base. And form a good low resistance ohmic contact.
Advantages of eutectic welding:
Eutectic alloy technology has been widely used in the electronic packaging industry, such as the bonding of the chip and the substrate, the bonding of the substrate and the package, and the cap of the package. Compared with traditional epoxy conductive adhesive bonding, eutectic welding has the following characteristics:
·High thermal conductivity;
·Small resistance;
·Heat transfer block;
·Strong reliability;
·Big shearing force after bonding;
·Good heat dissipation.
For power devices with higher heat dissipation requirements, eutectic welding must be used. Eutectic welding uses the characteristics of eutectic alloys to complete the welding process. For more information, please follow Shenzhen Guangmai Technology Co
