thank uguys...
one question .consider one net.if width of the metal =2micron length of the metal =5micron now i'm increasing metal width=4 so wat ab net delay?increse or decrese.resistence ll increase wat about capacicance?
How do you figure that out?
From that formula, for a given length: increase in the radius a => decrease in l/a => decrease in ln(l/a) => increase in capacitance.
As in most cases, the question suffers from an incomplete problem specification. Wire capacitance and inductance are unknown without defining the full geometry.
To refer to a well-defined case with known electrical properties, you can assume that the wire is part of a transmission line, either coaxial or parallel wires. Then increasing the diameter will increase capacitance per length unit and decrease inductance. As a result the characteristic impedance Z = Z0*√L/C will decrease, but the propagation speed (~ √LC) stays constant.
To give a first order estimation, I would expect a similar behaviour for arbitrary wire geometries, e.g. bond wires.
To avoid electromigration , one of the way is to choose wire width according to drive strength. So if i choose wider width wire for higher drive strength gate , it will have more capacitance. It will thus increase parasitic.
Am i correct ? if yes , then what factor we should focus more , resistance or capacitance ?