COB English Chip On Board: It means to fix the bare IC chip on the printed circuit board through the help (i.e. chip packaging on board)

It is a way of wiring in the chip production process. It is generally used to connect the internal circuit of the chip with the packaging pin with gold wire before packaging. Generally, after bonding (that is, after the circuit is connected with the pin), the chip is packaged with black gel, and the advanced external packaging technology COB is adopted. The process flow of this process is to implant the tested wafer into the special circuit board, then connect the wafer circuit to the circuit board with gold wire, and then cover the melted organic material with special protection function on the wafer to complete the later packaging of the chip.

1、 COB Bonding excipients:

1. Bonding glue

For the encapsulation of bare film, there are hot glue, cold glue, bright glue, matt glue, high glue and low glue. The difference between hot and cold adhesive is that the PCB needs to be preheated to a certain temperature when the hot adhesive is used for sealing, and the cold adhesive does not need to be preheated at room temperature when sealing, but the hot adhesive is better than the cold adhesive in terms of performance and curing appearance, which can be selected according to the product needs. The difference between gloss adhesive and matt adhesive is that the appearance after curing is bright or matt. The difference between high glue and low glue is the stacking height of glue during encapsulation. If there is any requirement for the height of glue after curing, please consider it when purchasing.

2. Red gum

It is used for the bonding of insulating bare sheet. This item can also be directly bonded with Bonding adhesive.

3. Conductive silver glue

For the bare sheet that needs to be bonded with conductive adhesive, decide whether to buy it according to the need

4. Aluminum wire or gold wire

Connection between bare chip and PCB

2、 COB states several precautions:

1. The ordinary vacuum suction pen itself is easy to be damaged, and because of the metal at the pen head, it is easy to scratch the bare film, so it is recommended to use a vacuum pump, and the suction pen head is covered with a silicone tube to ensure safety.

2. Before bonding, the bare film should be checked to see if there are scratches, oxidation and other phenomena.

3. Take anti-static measures.