Damage isolation by shaped beam delivery in laser scribing process
AssigneeApplied Materials, Inc.
InventorsJames M. Holden, Nir Merry, Todd Egan
Life of this patent
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Abstract
Methods and apparatuses for dicing substrates by both laser scribing and plasma etching. A method includes laser ablating material layers, the ablating by a laser beam with a centrally peaked spatial power profile to form an ablated trench in the substrate below thin film device layers which is positively sloped. In an embodiment, a femtosecond laser forms a positively sloped ablation profile which facilitates vertically-oriented propagation of microcracks in the substrate at the ablated trench bottom. With minimal lateral runout of microcracks, a subsequent anisotropic plasma etch removes the microcracks for a cleanly singulated chip with good reliability.
Claims13
A method of dicing a substrate comprising a front surface having a plurality of ICs thereon and having a back surface opposite the front surface, the method comprising:
- receiving the substrate with an unpatterned mask on the front surface of the substrate, the unpatterned mask covering and protecting the ICs and a thin film IC stack;
- ablating with a laser a predetermined pattern of trenches into the mask, into the thin film IC stack and partially into but not through the substrate, the laser having a beam with a centrally peaked spatial power profile, each of the trenches having a first kerf at an interface of the thin film IC stack and substrate;
- and
- plasma etching through the trenches in the substrate to form corresponding trench extensions and to singulate the ICs, each of the corresponding trench extensions having the first kerf.
A method of dicing a silicon substrate comprising a front surface having a plurality of ICs thereon and having a back surface opposite the front surface, the method comprising:
- receiving a substrate with a mask on the front surface of the substrate, the mask covering and protecting the ICs and a thin film IC stack;
- ablating with a femtosecond laser a predetermined pattern of trenches into the mask, into the thin film IC stack and partially into but not through the substrate, the ablating forming a trench in the mask having a first kerf width adjacent to and interface between the thin film IC stack and the substrate and having a second kerf width below the interface at a bottom of the ablated trench, the second kerf width being smaller than the first kerf width to form a sloped substrate sidewall along a plane substantially perpendicular to a direction of laser travel;
- and
- plasma etching through the trenches in the silicon substrate to form corresponding trench extensions and to singulate the ICs and remove microcracks originating at a the bottom of the ablated trench, each of the trench extensions having the first kerf width.
Dependencies are inferred from the claim text.