Commonly-used laser types include CO2, Nd:YAG (neodymium-doped yttrium aluminum garnet) and excimer UV lasers. Each of these lasers has its place in micromachining, but not all are suited to high-precision micromachining where clean, precise cuts are required. The following table summarizes the power and applications for each of these laser types:
Laser Type |
Wavelength |
Beam Type |
Average Power |
Application |
|---|---|---|---|---|
CO2 |
9.6 to 10.6µm |
CW pulsed |
0.3 to 10kW |
Heavy industrial |
Nd:YAG |
1.06µm |
CW Q-switched pulse |
0.1 to 1kW |
Light to heavy industrial Some high precision |
Other solid state |
0.6 to 1.06µm |
CW pulsed |
0.1 to 1kW |
Light to heavy industrial Some high precision |
Excimer |
0.19 to 35µm |
Pulsed |
<150W |
High precision |
As you can see, excimer lasers have lower power requirements than other lasers and are primarily used for high-precision applications. CO2 and Nd:YAG lasers, which operate in the infrared electromagnetic spectrum, produce 5 to 10 times the average power of excimers. Excimer lasers, which operate in the ultraviolet electromagnetic spectrum, do not generate heat and, therefore, have a minimal thermal effect on surrounding materials. Excimer lasers process materials using photo-chemical ablation, a process by which materials are turned directly into gas by breaking chemical bonds.
The following table depicts the differences in how CO2, Nd:YAG and excimer lasers affect materials.
CO2 Lasers |
Nd:YAG Lasers |
Excimer Lasers |
|
|---|---|---|---|
Material Interaction |
Thermal input |
Thermal input |
Photo-chemical ablation |
Penetration depth |
5 to 10µm |
1µm |
0.1 to 0.3µm |
Ultimate feature resolution |
10µm |
2µm |
0.2µm |
Practical feature resolution |
50µm |
25µm |
1µm |
Affect on surrounding material |
Pronounced |
Pronounced |
Minimal |
As you can see, excimer lasers are capable of very fine feature resolution compared to CO2 and Nd:YAG lasers.