In an electronics factory, what is COB processing and what is SMT processing? What is binding processing and what is plug-in processing? I can't say clearly.

1, Chip On Board (COB) process: firstly, the surface of the substrate where the silicon wafer is placed is covered with heat-conducting epoxy resin (generally epoxy resin doped with silver particles), then the silicon wafer is directly placed on the surface of the substrate and heat-treated until the silicon wafer is firmly fixed on the substrate, and then the electrical connection between the silicon wafer and the substrate is directly established through wire bonding.

2.SMT is a surface mount technology (short for Surface Mounted Technology), and it is the most popular technology and process in electronic assembly industry.

It is a circuit assembly technology in which surface assembly components without leads or short leads (SMC/SMD for short) are mounted on the surface of printed circuit board (PCB) or other substrates, and then soldered and assembled by reflow soldering or immersion soldering.

3. Plug-in processing is to weld plug-in components on PCB.

4. Binding means bonding, wire bonding, and gold wire and aluminum wire.

Extended data:

Cob: (chip on board) is bonded to the printed board, because IC suppliers are reducing the output of QFP (a packaging method) packaging in LCD control and related chip production. Therefore, the traditional patch method will be gradually replaced in future products.

The main welding methods are

1, hot-pressing welding

The metal wire and the welding area are pressure welded together by heating and pressing. The principle is that the welding area (such as AI) is plastically deformed by heating and pressurizing, and the oxide layer on the bonding interface is destroyed, so that the attraction between atoms can achieve the purpose of "bonding".

In addition, when the interface between the two metals is uneven, the upper and lower metals can be embedded in each other when heated and pressurized. This technology is usually used as the on-board glass chip COG.

2. Ultrasonic welding

Ultrasonic welding uses the energy generated by ultrasonic generator, and the transducer rapidly expands and contracts under the induction of ultra-high frequency magnetic field to generate elastic vibration, which makes the cleaver vibrate correspondingly, and at the same time exerts certain pressure on the cleaver. Under the combined action of these two forces, the cleaver drives the AI wire to quickly rub on the surface of the metallization layer (AI film) in the welding area, so that the AI wire and the AI film surface are plastically deformed.

This deformation also destroys the oxide layer at the interface of AI layer, making two pure metal surfaces closely contact to realize atomic bonding, thus forming welding. The main welding material is aluminum wire welding head, which is generally wedge-shaped.

3. Gold wire welding

Ball bonding is the most representative welding technology in wire bonding, because the current semiconductor package and triode package adopt AU wire ball bonding.

The operation is simple and flexible, the solder joint is firm (the welding strength of gold wire with a diameter of 25UM is generally 0.07 ~ 0.09n/ point), and the welding speed is as high as 65438 0.5 points/second.

Gold wire welding is also called thermal (pressure) (ultrasonic) welding. The main bonding material is gold (AU) wire, so it is ball bonding.

Baidu encyclopedia -—COB

Baidu Encyclopedia -—SMT Patch

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