Basic knowledge of LED wire bonding requirements and bonding equipment introduction

Basic knowledge of LED welding line requirements

1 Purpose

Under the joint action of pressure, heat and ultrasonic energy, a good ohmic contact between the chip electrode and the outer lead bonding area is formed.

2 technical requirements

2.1 gold wire and chip electrode, lead frame connection section is firmly connected.

2.2 gold wire pull: 25 m gold wire F minimum >5CN, F average >6CN: of 32 m gold wire F minimum >8CN, F average >10CN.

2.3 solder joint requirements

2.3.1 gold wire bonding after the first and second solder joints as shown (Figure 1), figure (2)

2.3.2 Golden Globe and contract size

The ball diameter A: 25um diameter wire: 60-75um, which is 2.4-3.0 times the diameter of the;

The ball type thickness H: 25um diameter wire: 15-20um, which is 0.6-0.8 times the diameter of the;

Wedge wire length D: phi 25um: 70-85um, which is 2.8-3.4 times the diameter of the;

There is no obvious damage or thinning phenomenon in the roots of 2.3.3, and there is no obvious crack in the joint.

2.4 welding line requirements

2.4.1 each gold wire bonding arch wire is highly appropriate, no collapse silk, silk, no extra wire.

2.5 gold wire pull

The tensile force of the first solder wire of the 2.5.1 is tested with the highest point of the welding wire, and the surface of the lead frame is pulled upward from the highest point of the welding wire under the microscope. As shown in the figure:

Bond tension and breakpoint position requirements:

3 process conditions

Because of different sets of parameters are different, there is no way to unify. I'm here to talk about the main place to set:

Bonding temperature, the welding time of the first second solder joints, welding pressure, welding power, the height of the arch wire, the bulb current, the length of the tail wire, etc..

4 note

4.1 no direct contact with the chip on the bracket and the bonding area.

4.2 operators need to wear anti-static bracelet, wear anti-static overalls, to avoid static damage to the chip.

4.3 materials should be careful in handling, avoid electrostatic and anti collision, inverted wire, wire, wire and attached collapse debris.

4.4 bond machine failure, should be in a timely manner in the bonding of the work out of the heating plate, to avoid the material in the heating block baking for a long time and cause the silver glue cracking and stent discoloration.