In the fabrication of multilevel integrated circuits, each metal layer is anarized by heating to momentarily melt the layer. The layer is melted by sweeping laser pulses of suitable width, typically about 1 microsecond duration, over the layer in small increments. The planarization of each metal layer...http://www.google.com/patents/US4814578?utm_source=gb-gplus-sharePatent US4814578 - Planarization of metal films for multilevel interconnects
