A method and apparatus for selecting programmable interconnects to reduce clock
skew is described. A routing tree for clock signals is created having routes and
clock pin nodes. Delays of the clock signals to the clock pin nodes are determined.
The routing tree is balanced to a target clock skew, such as zero clock skew, for
the clock signals provided to the clock pin nodes. Programmable interconnect circuits
are selectively added to reduce clock skews of the clock signals, where the clock
skews being reduced at the clock pin nodes are for at least a portion of the clock
pin nodes. Additionally described are determining clock propagation delays to clock
pins and balancing a clock tree using computer aided design.