We have developed a new type of an excimer laser machining system using a holographic optical element (HOE). It is a multi-zone homogenizer which illuminates the diffracted beam to only the mask open area.
In an excimer laser machining system, a mask imaging system is conventional. But the mask open area ratio is generally 1% or less. Thus the total energy efficiency is less than 1%.
To refine this condition, We have applied a HOE to the mask imaging system. Using this system, we obtained the mask transmission rate of 33% and the total energy efficiency of 12%.
This is more than 10 times larger than other conventional mask imaging systems.