The Next Generation of Semiconductor Manufacturing
Extreme Ultraviolet (EUV lithography represents a major technological advancement for semiconductor manufacturing. Current lithographic techniques utilize deep ultraviolet (DUV) light sources that produce wavelengths of 248 nm or 193 nm. The extreme ultraviolet light used in EUV lithography has a wavelength of 13.5 nm, a full order of magnitude shorter. This is important because the imaging capabilities - or resolution - of a lithography system are proportional to (and limited by) the wavelength of light used. An EUV light source produces this short wavelength light in a system called Laser Produced Plasma (LPP). LPP light sources utilize a high power laser to create a high energy plasma that emits short wavelength light inside a vaccum chamber.
How is EUV different from the prior lithography technologies?
There are multiple ways that EUV differs, mostly associated with the methods to create and transport the short wavelength light. Traditional lenses cannot be used with EUV as they absorb the light. A mirror with a highly specialized coating, called a multilayer mirror (MLM) must be used. Even these special mirrors still absorb about 30% of the light so it is advantageous to use as few as possible.
Any gas in the light path, such as air or nitrogen, will also absorb the light - thus the entire light path is inside a vacuum chamber.