Laser dicing to control splash

A method comprising:

• directing a first laser beam at a surface of a semiconductor substrate with an entry point along a scribe street thereof, wherein the first laser beam is focused inside the substrate to form a first modified region and an embedded first crack extending from the first modified region along a direction orthogonal to the surface and having a length that is less than a thickness of the substrate;
• directing a second laser beam at the surface focused to have a second focal point inside the substrate to form a second modified region, which is offset from the first modified region in a direction orthogonal to a scan direction of the second laser beam, and a second crack extending the first crack toward the surface;
• and
• directing a third laser beam at the surface focused to have a third focal point inside the substrate to form a third modified region, which is offset from the first and second modified regions, and a third crack and offset from the first crack in a direction that is orthogonal to a scan direction of the third laser beam.

A system comprising:

• a stage configured to hold at least one semiconductor wafer having first and second surfaces, the wafer including a plurality of semiconductor die having active circuitry at the second surface separated by respective scribe streets;
• a laser system having a laser module supported above the stage, the laser module configured to direct a pulsed laser beam toward the stage;
• and
• a control system coupled to the stage and the laser system, the control system configured to:
• control the laser system and the stage to direct a first laser beam at the first surface with an entry point along a particular scribe street thereof and focused inside the wafer to form a first modified region and an embedded crack extending from the first modified region along a direction orthogonal to the second surface;
• control the laser system and the stage to direct a second laser beam at the first surface along the particular scribe street focused to have a second focal point inside the wafer to form a second modified region, which is offset from the first modified region in a direction orthogonal to a scan direction of the second laser beam, and a second crack being an extension of the first crack toward the first surface;
• and
• control the laser system and the stage to direct a third laser beam at the first surface along the particular scribe street focused to have a third focal point inside the wafer to form a third modified region, which is offset from the first and second modified regions, and a third crack, which offset from the first crack in a direction that is orthogonal to a scan direction of the third laser beam.