Different Pins In Clock Tree Synthesis

What is the difference between through pin, leaf pin and exclude pin.

These are clock tree exceptions and are declared before clock tree synthesis to guide the tool for timing analysis and skew balancing. We can control clock tree tracing by including or excluding particular pins explicitly.

Leaf Pin: CTS treats the pins as sinks, stops tracing further and balances clock skew.

Exclude Pin: CTS would exclude the pins from Skew analysis.

Through Pin: CTS treats a clock sink pin as Through pin, which allows cts tracing further and balances clock skew.