Package 4-The development process of packaging - material aspect

Package 4-The development process of packaging - material aspect

1. Metal material

The development of packaging materials also promotes the progress of packaging technology. This type of packaging is mainly made of metals such as tungsten, steel, copper and aluminum.

2. Ceramic material:

These single metals are difficult to cope with the development of modern packaging, so they have evolved to use ceramic materials for packaging. Most of the ceramic materials are oxides, nitrides, etc. Since the chemical bonds are usually ionic bonds and covalent bonds, the stability of ceramics is good;

3. Plastic material

Plastic packaging has the characteristics of low cost, simple process, and suitable for automatic production. It is widely used until now.

Package Pin Development

1. Long lead wire in-line

The initial pin shape of the package is long lead in-line;

2. Short lead or leadless mounting

Later, it developed into short-lead or leadless mounting; as the name suggests, short-lead means that the pins are shorter, and leadless mounting is a form of packaging that does not use pins.

3. Ball bump

Ball bumps are made on the back of the printed substrate in an array to replace pins. Mount LSI chips on the front side of the printed substrate. It is then sealed with mosaic resin or potting.

Development of packaging and assembly methods

1. Through-hole Package

Insert components into existing holes on the printed circuit board. Soldering of electronic components by hand assembly or automatic insertion loader.

2. Surface mount

Surface assembly does not need to drill insertion holes on the printed board, and directly pastes or solders the surface mounted components to the specified position on the surface of the printed board.

Compared with traditional packaging technology, surface packaging technology has the advantages of high reliability, low cost, miniaturization and automation of production. Surface packaging has high requirements for assembly accuracy and assembly quality, and the assembly process is also very strict. Directly follow, as the name implies, it is directly assembled.

3. Classification according to the loading method When the bare chip is loaded, its electrode side can face up or down; therefore, the chip has the style of front-mount and flip-chip. In addition, when the bare chip is packaged, their electrical connection The way is also different, some use wire bonding, and some use no wire bonding. The substrate can mount and hold bare chips. At the same time, it has the functions of insulation, heat conduction, isolation and protection. From a structural point of view, the substrate has single-layer, double-layer, multi-layer and composite