What are the best Interconnect trategies in VLSI Layout design?

I think focusing on minimizing interconnect lengths is a key strategy. For lower layers like M1 and M2, I usually assign local signals because they’re closer to the transistors and have lower resistance. For M7 and M8, I reserve them for global signals, power, and ground. Shorter interconnects in M1 and M2 reduce delays and improve performance. Also, clustering related components and using hierarchical routing can significantly reduce congestion.

We believe utilizing the metal layers efficiently is important. In our designs, we use M1 and M2 for local interconnects, like connecting cells within a block. M3 to M6 is great for intermediate-level routing, where you can balance signal propagation and avoid crosstalk. M7 and M8 are ideal for power delivery and clock distribution. You should optimize shielding and spacing in M7 and M8 to ensure signal integrity and minimize noise.

In my experience, the best strategy is to balance performance and reliability across layers. For example, I assign wider lines for power and ground on M7 and M8, which helps improve reliability. On M3 through M6, I adjust line widths and spacings for signal propagation while managing coupling capacitance. Shield wires are essential in M5 and M6 for critical signals. For M1 and M2, I focus on dense routing with minimal wire lengths for efficiency and manufacturability.