PCB Tech - During PCB production: What are the auxiliary materials for COB bonding processing?

COB bonding processing is to fix the IC die wafer on the PCB board through the COB bonding machine, also called chip on board packaging, and then use aluminum wire or money packaging pins to connect to the PCB. Usually the COB wafer is bonded Later, that is, after the circuit is connected to the wafer pins, the chip is packaged with black, white, and red glue. Note that the PCB board can only use gold-plated, immersed gold, and nickel-plated processes, and must not use tin-spraying processes. The characteristic is the COB bonding processing technology, the finished material is relatively lower than the SMT patch processing, but the labor cost in COB bonding is higher. So, what are the auxiliary materials for COB bonding? There are mainly 4 kinds of COB bonding auxiliary materials, which 4 kinds are, let's come to understand which ones are together!

1. Aluminum wire: The aluminum wire we use is a combination of aluminum and silicon, 1mil, 1.25mil aluminum wire, the operator should not touch the wire on the spool when disassembling, its starting end Generally, it comes out with a red band meter. Different models have different threading paths, which are used to connect the circuit pads on the chip to the PCB board.

2. Steel mouth: The steel mouth is made of special steel, so we call it a steel mouth. There is a small hole at the lower end to pass the aluminum wire. Be careful not to hit the steel mouth with any objects during operation to avoid damage to the steel mouth. The function is to press and weld the aluminum wire to form and fix it according to the standard requirements.

3. Red glue: Red glue is a kind of high-strength bonding glue, which is oil-proof, waterproof, shockproof, anti-corrosion and other fluids after curing. It is suitable for the combination of bare chip (IC) and other metals, and the function is to fix the chip on the PCB as required.

4. Black glue: Black glue is a kind of epoxy resin encapsulation material with high reliability. It is suitable for the application of COB encapsulation of semiconductor components. The encapsulation is fixed to prevent damage from improper external conditions.

Someone may ask, is the special eraser for the circuit board counted as an auxiliary material for the IC bonding machine? The special eraser for the circuit board can also be regarded as it, because it is necessary for the process flow. COB bonding is to use a bonding machine to connect the bonding IC and the circuit board with a bonding wire, including scanning the board, dispensing red glue, sticking IC, bonding, pre-testing, sealing vinyl, baking, and post-testing processes. Circuit boards that require COB bonding processing are often used in the fields of thermometers, clinical thermometers, skipping ropes, calipers, electronic scales and multimeters.