Integrated circuits are manufactured through a lithographic process on a semiconductor wafer. In lithography, similarly to chemical photography, a semiconductor wafer is covered with a photosensitive emulsion and then selectively exposed to light to form the electronic components. Due to miniaturization, this process is to be performed with nanometer accuracy and at the highest possible speed. Sophisticated apparatus and methods have been developed for this purpose. Figure P5.44 shows the block diagram of a scanner dedicated to this purpose (Butler, 2011). Use Mason’s Rule to find:

a. The transfer function X_ss(s)/R(s).

b. The transfer function X_ls(s)/R(s).

Eu C(s) H(s) X Diff Es C(s) R Hs) X FIGURE P5.448