Flow information is stored on the file system using an easily readable,
LISP -like format with non-positional parameter passing
.
Figure 5.6 shows a short sequence of
simulator-specific steps defining a lithography module as a block
of a larger process flow.
The file format is completely encapsulated and need not be accessed by the
user or by any application, but only through the programming interface
and the GUI for the flow description. It is easy to read with any
LISP interpreter or, for C or FORTRAN applications, through a library
for hierarchical data exchange (HDX) [Pla96], which provides
an object-oriented memory representation of nested data structures
and supports reading and writing of nested lists of data.
Figure 5.6:
ASCII representation using LISP syntax
of a lithography process module.
The module comprises a resist spin-on step, an exposure step
(with mask), and a develop step.
NIL is the LISP representation for the empty set or void.