Bonding is a fashion of NTC chip wiring. It’s usually used before encapsulation to connect the circuit inside the chip and the encapsulated pin or PCB gold-plating copper foil by golden wire or aluminium wire. The ultrasonic wave from ultrasonic generator (usually it’s 40-140KHz) engenders high-frequency vibration throught transducer. The vibration is transferred to cleaver through ultrasonic transformer. When the cleaver gets in touch with the bonding wire and soldered part, the metal surfaces ready to be solded will have friction mutually, then the oxidation film will be destroyed and engender plastic deformation, so two pure metal surfaces contact tightly up to atomic distance standard. Finally it forms firm mechanical connection. After bonding (the circuit connects to the pin), the chip will be encapsulated by black resin.
Advantages of bonding tech comparing with traditional SMD tech:
Bonding is much better than SMT in the aspect of anticorrosion, anti-seismic and stability of end product. At present, SMT tech is applied in a great quantity only connect the pin of the chip to PCB. This production engineering is not suitable for the process of products which needs removable storage. There are rosin joint, tack weld or missing weld. As the welding spots in PCB are exposed in air for a long time in daily use, it’s easily affected by spontaneous or artificial factor such as humidity, static, physical wear, subacidity, etc., and so it’s easily have problems of short circuit, open circuit, even burnout of the product. Bonding chip connects the circuit inside the chip and the encapsulated pin by golden wire, and then accurately encapsulated by organic material with special protective effect. After later period encapsulation, the chip is totally protected by organic material and seperated from external environment so that there is no humidity, static or erosion. Simultaneously, the organic material melts in high temperature, covers the chip and is dried by device, so seamless connection is formed. No physical wear happens so that stability is much better.
2. Bonding is much more flexible and convenient than SMD in the aspect of installing position and method. In the traditional SMD tech, the component shall be placed at the set PCB spot. In bonding tech, the component can be placed at any ideal position and no limitation from PCB spot place.
Bonding tech can be applied in music card, toy, telephone, mobilphone, PDA, MP3 player, digital cemera, games player, etc.