2.1 Immersion lithography.pdf - Immersion lithography In the projection mode of photolithography system optics or projection system plays the role in

2.1 Immersion lithography.pdf - Immersion lithography In...

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Immersion lithography In the projection mode of photolithography system, optics or projection system plays the role in putting the mask pattern on to the resist, coated on a wafer or any substrate. The Numerical Aperture of the optics limits the system to resolve very small features of the pattern in the range of 100 nanometers or less on the resist. This limitation can be overcome in the immersion photolithography system by increasing the refractive index of the projection optics. Immersion photolithography is simply a means of increasing the refraction index and resolution of the interface between the lens, and the resist surface, thus allowing smaller feature sizes. According to Rayleigh criterion, the resolution in the optical system is defined as R = Kλ/NA (NA= n sinθ, n is the refractive index) Where K is the process factor, λ is the wavelength of the light and NA is the numerical aperture According to Rayleigh's equation, there are three ways to enhance the resolution. The first is to shorten the exposure wavelength. The second is to improve the k (a constant, depends on resist
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  • Fall '18
  • jane smith
  • pH, Wavelength

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