With a 2-d chip, you can't do much better than a big-old heat sink, and circulating a fluid. For 3-d structures, I wonder if actively moving heat to the outsid

With a 2-d chip, you can't do much better than a big-old heat sink, and circulating a fluid. For 3-d structures, I wonder if actively moving heat to the outside with Peltier junctions would help.