Method and apparatus for laser dicing of wafers
AssigneeInternational Business Machines Corporation
InventorsRUSSELL A. BUDD, Bing Dang, John U. Knickerbocker
Life of this patent
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Abstract
A method includes cutting a semiconductor wafer on a substrate wafer using at least one laser. By setting the laser to a set of parameters that define a laser beam, the laser beam can avoid ablation of the substrate wafer. The laser beam is also set equal to, or within, an ablation threshold of the semiconductor wafer for selectively ablating the semiconductor wafer. The set of parameters includes wavelength, pulse width and pulse frequency.
Claims25
A method comprising:
- cutting a semiconductor wafer on a substrate wafer by at least one laser;
- and
- setting said at least one laser to a set of parameters defining a laser beam, said laser beam avoiding ablation of said substrate wafer,
- wherein said laser beam is set equal to or within an ablation threshold of said semiconductor wafer for selectively ablating said semiconductor wafer;
- and
- wherein said set of parameters includes wavelength, pulse width and pulse frequency.
A method of dicing wafers comprising:
- selectively dicing a silicon wafer bonded to a substantially transparent substrate by a laser;
- setting said laser to have a laser beam with at least one wavelength in a range of about 200 nm to 500 nm;
- setting said laser such that said laser beam has at least one pulse width within a range of pulse widths between about 50 femtoseconds and 10 nanoseconds;
- and
- setting said laser such that said laser beam has at least one pulse frequency within a range of pulse frequency from about 100 to 100,000,000 pulses per second, such that said laser beam is equal to or below an ablation threshold of said substantially transparent substrate and said laser beam is equal to or above an ablation threshold of said silicon wafer for dicing said silicon wafer while said substantially transparent substrate supports said silicon wafer.
An apparatus for dicing a semiconductor wafer on a glass wafer, said apparatus comprising a laser adapted to emit a laser beam, said laser beam having parameters selected to avoid ablation of said glass wafer;
- said parameters selected to cause ablation for dicing said semiconductor wafer such that said glass wafer is re-useable after dicing of said semiconductor wafer is completed;
- and when said laser beam parameters include wavelength, pulse width and pulse frequency.
Dependencies are inferred from the claim text.