Metal packaging is a form of electronic packaging with metal as the shell or base, the chip is mounted on the shell or base directly or through a substrate, and the leads pass through the metal shell or base. Glass-metal sealing technology is often used. It is widely used in the packaging of hybrid circuits, mainly military and customized special hermetic packaging.

It has been widely used in many fields, especially in the military and aerospace fields. Metal packaging forms are diverse and processing is flexible. It can be integrated with certain components (such as hybrid integrated A\/D or D\/A converters). It is suitable for single-chip and multi-chip applications with low I\/O numbers, and is also suitable for radio frequency, microwave, optoelectronics, surface acoustic wave and high-power devices, which can meet small batches and high reliability. In addition, in order to solve the heat dissipation problem of packaging, most types of packaging also use metal as heat sinks and heat sinks.

Mainly introduces the metal materials used and being developed in metal packaging. These materials include not only metal packaging shells or bases, metal materials used for leads, but also metal materials that can be used for various packaging substrates, heat sinks and heat sinks.

The coefficient of thermal expansion (CTE) of chip materials such as Si and GaAs and ceramic substrate materials such as A12O3, BeO and AIN is between 310-6-710-6K-1. In order to achieve chip support, electrical connection, heat dissipation, mechanical and environmental protection, metal packaging materials should meet the following requirements:

① Low thermal expansion coefficient matching the chip or ceramic substrate, which can reduce or avoid the generation of thermal stress;

②Good thermal conductivity, providing heat dissipation;

③Good electrical conductivity, reducing transmission delay;

④Good EMI\/RFI shielding ability;

⑤ Lower density, sufficient strength and hardness, good processing or molding performance;

⑥Platability, weldability, corrosion resistance, reliable combination with chips, cover plates, and printed boards, sealing and environmental protection;

⑦Reduce costs.

Traditional metal packaging materials include Al, Cu, Mo, W, steel, Kovar, Cu\/W and Cu\/Mo, etc.