Multi-step and asymmetrically shaped laser beam scribing

A method of dicing a substrate comprising a plurality of ICs, the method comprising:

• receiving the substrate with an unpatterned polymeric mask covering and protecting the ICs;
• ablating with a laser a predetermined pattern of trenches into the mask and into a thin film IC stack disposed below the mask to expose a portion of a substrate, the ablating leading with electromagnetic radiation having a first irradiance and following with electromagnetic radiation having a second irradiance, lower than the first, wherein the first irradiance is sufficient to ablate a non-polymeric layer of the thin film IC stack under the mask and wherein the second irradiance is insufficient to ablate the non-polymeric layer;
• and
• plasma etching the through substrate exposed by the patterned mask trenches to singulate the ICs.