List of Figures

• 2.1 Optical resolution enhancement in past, present and future
• 2.2 Depth of focus as a function of numerical aperture and image resolution
• 2.3 Basic operation principle of optical lithography
• 2.4 A schematic modern optical projection printing system
• 2.5 Effects of partial coherence in line printing
• 2.6 Types and operation principle of phase-shifting masks
• 2.7 Contrast curves for idealized positive and negative photoresist
• 2.8 Important steps in photoresist processing
• 3.1 Basic modules of a typical photolithography simulator
• 3.2 Bossung plots of the focus-exposure matrix
• 3.3 Process window and exposure latitude
• 3.4 Normalized image log-slope versus depth of focus
• 4.1 Range of validity of scalar diffraction theories
• 4.2 Thickness function of a thin lens
• 4.3 Numerical aperture of a lens
• 4.4 Image formation with a lens
• 4.5 Köhler illumination of an object
• 4.6 Ray path through a schematic projection system
• 4.7 Source discretization of an annular and quadrupole illumination system
• 4.8 Source discretization of a partially coherent illumination system
• 4.9 Transmission cross coefficients for partially coherent illumination
• 4.10 Semi-analytical computation of the photomask Fourier coefficients
• 5.1 Simulation flow of the exposure/bleaching module
• 6.1 Simulation domain of the differential method
• 6.2 Discretization procedure of the differential method
• 6.3 Truncation of Fourier expansion of the EM field
• 6.4 Multiple shooting employing decoupling and reorthogonalization
• 6.5 Summary of the differential method
• 6.6 Propagating and evanescent modes
• 7.1 Prebake dependence of absorption parameter for the KODAK 820 resist
• 7.2 Development rate of the IBM APEX-E chemically amplified resist
• 7.3 Cellular structuring element algorithm
• 8.1 Layout of a 4:16 multiplexer
• 8.2 Layout layers of interest of the 4:16 multiplexer
• 8.3 Aerial images for best focus
• 8.4 Aerial images for best focus (zoomed)
• 8.5 Aerial images for a defocus of 1 $\mu$m
• 8.6 Aerial images for a defocus of 1 $\mu$m (zoomed)
• 8.7 Resolution enhancement techniques
• 8.8 Resolution enhancement for dense patterns at best focus
• 8.9 Resolution enhancement for dense patterns at best focus (cont.)
• 8.10 Resolution enhancement for dense patterns at a defocus of 1 $\mu$m
• 8.11 Resolution enhancement for dense patterns at a defocus of 1 $\mu$m (cont.)
• 8.12 Resolution enhancement for sparse patterns at best focus
• 8.13 Resolution enhancement for sparse patterns at best focus (cont.)
• 8.14 Resolution enhancement for sparse patterns at a defocus of 1 $\mu$m
• 8.15 Resolution enhancement for sparse patterns at a defocus of 1 $\mu$m (cont.)
• 8.16 Schematic of the simulated topography
• 8.17 Source points of the simulated illumination apertures
• 8.18 Contact hole for coherent illumination over a planar silicon substrate
• 8.19 Contact hole for circular illumination over a planar silicon substrate
• 8.20 Contact hole for quadrupole illumination over a planar silicon substrate
• 8.21 Contact hole for coherent illumination over an oxide step
• 8.22 Contact hole for circular illumination over an oxide step
• 8.23 Contact hole for quadrupole illumination over an oxide step
• 8.24 Contact hole for coherent illumination over an a-silicon step
• 8.25 Contact hole for circular illumination over an a-silicon step
• 8.26 Contact hole for quadrupole illumination over an a-silicon step
• 8.27 Resist profiles of the contact holes printed over a planar substrate
• 8.28 Resist profiles of the contact holes printed over a dielectric step
• 8.29 Resist profiles of the contact holes printed over a reflective step
• A.1 Approximation of the inclination factor
• C.1 Analysis of a homogeneous planar layer
• C.2 Analysis of a stratified medium
• D.1 Lateral dependence of the permittivity at a nonplanar material interface
• D.2 Truncation error for a nonplanar material interface