A fast method of estimating capacitances and wire delays in an integrated circuit
design is based on placement information such as that contained in a gate schematic
net list from a logic synthesis tool. A simple tree topology called a spine tree
is constructed to connect the pins of the net as an approximation of actual connections
therein. Capacitance is extracted for this topology assuming a worst case scenario,
and Elmore delays are computed for the wire delays based on the worst-case capacitances.
The method takes linear time as a function of the number of pins in the net and
is much faster than using a Steiner tree method in this context.