Laser-based material processing methods and systems

A laser-based system for scribing, dicing, cutting, or processing of a multi-material workpiece comprising a semiconductor material and a pattern while limiting accumulation of redeposited material, the pattern comprising at least one of a dielectric material and a metal material, the system comprising:

• at least one source of optical pulses, said at least one source of optical pulses configured to generate long pulses having long pulse widths up to about 10 nanoseconds and ultrashort pulses having ultrashort pulse widths in a range from ten femtoseconds to about 500 picoseconds, said long pulse widths longer than said ultrashort pulse widths;
• an optical amplification system configured to amplify a pulse from the at least one source and to generate output pulses having at least one pulse width in a range from tens of femtoseconds to about 500 picoseconds;
• a modulation system, including at least one optical modulator, configured to provide a repetition rate of the output optical pulses to be in a range from at least about five hundred kHz to less than about five MHz;
• a beam delivery system configured to focus and deliver pulsed laser beams to the workpiece, wherein a pulsed beam is focused into a spot size (1/e2) of at least about 5 microns;
• and
• a positioning system configured to position said beams in multiple passes relative to the one or more materials of the workpiece, the positioning system configured to position said beams at a rate that is in a range of about 0.1 m/sec to about 10 m/sec that produces a spot overlap on or within the one or more materials of the workpiece, the spot overlap at least about 95% at said repetition rate and said spot size, wherein the spot overlap for removal of the material from at least a portion of the pattern is at least about ten times greater than the spot overlap for removal of the material from at least a portion of the semiconductor material, and wherein said laser-based system is configured such that:
• said long pulses are delivered to said pattern and said ultrashort pulses are delivered to said semiconductor material, and
• a depthwise extent of a heat affected zone (HAZ) generated during removal of the portion of the pattern by said long pulses is larger than a depthwise extent of HAZ generated during removal of the portion of the semiconductor material by said ultrashort pulses.