Conductor Material for LED Package

There are usually wires between LED chip and external pin.  If the wire goes wrong, the whole LED will be scrapped. Nowadays, LED has 4 kinds of internal wires.

Gold wire: stable performance, high price, mainly used in high-end packaging area. The main function of LED is shiny, discolouration and so on. Gold is generally used to prevent oxidation and ensure contact stability. The number of gold wires (actually chip electrodes) has little to do with the size of the chip, and 24 mil of the same has two electrodes and a single electrode. Gold wire is mainly related to the process and characteristics of the chip, generally single-electrode chips are vertical structure, the bottom can be directly electrified so less than an electrode, directly to the electrode substrate, this is generally red and yellow chip. The two-wire structure is mostly horizontal, positive and negative poles do in a plane, the bottom substrate insulation, this generally blue-green chip in the majority.

Alloy wire (also known as silver alloy wire): used to replace the traditional gold wire. In recent years, the price of gold has been rising. The price of gold wire used for Led packaging is also increasing. At the same time, the price of Led products is decreasing, so the cheap alloy wires should come out at times. The composition of the alloy wire is mainly single crystal silver, with a general content of 90%-99%. On the basis of gold wire doped with a large amount of silver and maintain the stability of IMC palladium and other components for a variety of trace elements.

1, the price is cheaper, lower than the price of gold wire, higher than the price of copper wire.

2. When soldering with silver plated bracket, the weldability is better.

3, the application of the old wire bonding equipment is immature or with nitrogen protection.

4, there is a certain degree of oxidation. This is the same disadvantage as copper wires, which use protective gases, but seem to use only nitrogen.

Silver wire: Silver wire is better stored than copper wire (copper wire must be sealed, and storage period is short, silver wire need not be sealed, storage period can reach 6-12 months)

1, hardness is low, machine parameter adjustment is not very large;

2, the current price is lower than the gold line, higher than the copper wire.

3, do not use gas protection when playing the line.

4, silver wire tension is not as strong as gold wire, but the decay time is better than silver, because silver does not absorb light.

Copper wire: single crystal copper wire and palladium plated copper wire.

1. Copper wire is inexpensive, and the cost of various specifications of copper wire used in wire bonding is only 1/3-1/10 of that of gold wire. It has great application potential in reducing cost.

2, the high stiffness of copper wire relative to the gold lead makes it more suitable for small wire bonding.

3. Copper wire is easily oxidized and the bonding process is unstable.

4. The physical parameters such as hardness and yield strength of copper wire are higher than those of gold and aluminum.