What are the objectives and techniques in cell placement?

Placement positions standard cells to optimize timing, area, power, and routability. Objectives: Minimize total wirelength, Meet timing constraints, Reduce congestion, and Minimize power (short wires = less capacitance). Techniques: Global placement (approximate positions minimizing cost function), Detailed placement (legalize to rows, cell ordering optimization), and Incremental placement (post-route optimization). Timing-driven placement uses timing criticality to guide optimization. Congestion-driven placement spreads cells in dense regions. Modern tools use analytical and machine-learning approaches for optimization.