Multi-step and asymmetrically shaped laser beam scribing

Abstract

Methods of dicing substrates by both laser scribing and plasma etching. A method includes laser ablating material layers, the ablating leading with a first irradiance and following with a second irradiance, different than the first. An asymmetrically shaped beam having an asymmetrical spatial profile along the direction of travel, multiple passes of a beam adjusted to have different irradiance levels, and multiple laser beams having various irradiance levels may be utilized to ablate at least a mask with the first irradiance and expose the substrate with the second irradiance.

What is claimed is: 
     
         1 . A system for dicing a semiconductor substrate comprising a plurality of ICs, the system comprising:
 a laser scribe module to pattern a mask and expose regions of a substrate between the ICs along a predetermined path, the laser scribe module to ablate a predetermined pattern of trenches into the mask and into a thin film IC stack disposed below the mask by leading with a first irradiance and following with second irradiance, different than the first;   a plasma etch module physically coupled to the laser scribe module, the plasma etch module to singulate the ICs by anisotropic plasma etching of the substrate; and   a robotic transfer chamber to transfer a laser scribed substrate between the laser scribe module and the plasma etch module in vaccuo.   
     
     
         2 . The system of  claim 1 , wherein the laser scribe comprises at least one laser having a wavelength less than or equal to 540 nanometers and a pulse width of less than or equal to 400 femtoseconds. 
     
     
         3 . The system of  claim 2 , wherein the at least one femtosecond laser is optically coupled to the substrate through beam shaping optics, the beam shaping optics to generate an asymmetrically varying irradiance profile along a direction of beam travel to generate a leading laser beam portion having the first irradiance and a trailing laser beam portion having the second irradiance. 
     
     
         4 . The system of  claim 2 , wherein the first laser is to operate at the first irradiance and wherein the laser scribe comprises a second laser having a wavelength less than or equal to 540 nanometers and a pulse width of less than or equal to 400 femtoseconds, the second laser to operate at the second irradiance. 
     
     
         5 . The system of  claim 1 , wherein the first irradiance is insufficient to ablate the single crystalline substrate and wherein the second irradiance is sufficient to ablate the single crystalline substrate. 
     
     
         6 . The system of  claim 1 , further comprising:
 a scanning device operable to control iterative ablation along a predetermined path relative to the substrate; and   a controller coupled with the scanning device, the controller to direct iterative ablation over substantially the same path.