Introduce COB's bonding wire and its pulling force
The previous article has introduced what COB is and the process of COB. Under the process, what kind of bonding wire and tensile test does COB have?
After the COB die is adhered and baked, the wire bonding process is followed. The COB process is different from IC packaging. It is gold wire for IC, and aluminum wire for COB. Therefore, the shape of the solder joint will be different, and secondly, the tensile force of the solder wire will also be different.
Wire Bonding
According to the shape of the solder joint, the wire bonding process can be divided into two types: "Ball Bond" and "Wedge Bond". COB usually uses aluminum wire (Al wire) so it will be Wedge Bond. However, according to experience and data, the strength of ball welding is better than that of wedge welding, but the "gold wire" is also more expensive.
Wire Pull Test
In the IC packaging process, the quality of the bonding wire is usually judged by three methods: Wire pull, die shift, and Ball Shift. Generally speaking, most COB The manufacturing process will only test the wire tension, which can measure whether the strength of the solder joints on the PCB is sufficient. The COB wire tension requirement is usually only greater than 3g according to the IPC specification (TM-650 2.4.42.3).
After the COB die is adhered and baked, the wire bonding process is followed. The COB process is different from IC packaging. It is gold wire for IC, and aluminum wire for COB. Therefore, the shape of the solder joint will be different, and secondly, the tensile force of the solder wire will also be different.
Wire Bonding
According to the shape of the solder joint, the wire bonding process can be divided into two types: "Ball Bond" and "Wedge Bond". COB usually uses aluminum wire (Al wire) so it will be Wedge Bond. However, according to experience and data, the strength of ball welding is better than that of wedge welding, but the "gold wire" is also more expensive.
Wire Pull Test
In the IC packaging process, the quality of the bonding wire is usually judged by three methods: Wire pull, die shift, and Ball Shift. Generally speaking, most COB The manufacturing process will only test the wire tension, which can measure whether the strength of the solder joints on the PCB is sufficient. The COB wire tension requirement is usually only greater than 3g according to the IPC specification (TM-650 2.4.42.3).
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