Laser scribing and plasma etch for high die break strength and clean sidewall

Abstract

In embodiments, a hybrid wafer or substrate dicing process involving an initial laser scribe and subsequent plasma etch is implemented for die singulation. The laser scribe process may be used to cleanly remove a mask layer, organic and inorganic dielectric layers, and device layers. The laser etch process may then be terminated upon exposure of, or partial etch of, the wafer or substrate. In embodiments, a multi-plasma etching approach is employed to dice the wafers where an isotropic etch is employed to improve the die sidewall following an anisotropic etch. The isotropic etch removes anisotropic etch byproducts, roughness, and/or scalloping from the anisotropically etched die sidewalls after die singulation.

What is claimed is: 
     
         1 . A system for dicing a substrate comprising a plurality of integrated circuits (ICs), the system comprising:
 a laser scribe module to pattern a mask to form a trench exposing regions of the substrate between the ICs;   an anisotropic plasma etch module physically coupled to the laser scribe module to anisotropically etch through a thickness of the substrate remaining after laser scribing;   an isotropic plasma etch module to isotropically etch sidewalls of a trench following anisotropic singulation; and   a robotic transfer chamber to transfer the laser scribed substrate from the laser scribe module to the anisotropic plasma etch module.   
     
     
         2 . The system of  claim 1 , wherein the laser scribe module comprises a femtosecond 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 1 , wherein the isotropic plasma etch module and the anisotropic plasma etch module are a same, single chamber. 
     
     
         4 . The system of  claim 3 , wherein the anisotropic etch etches completely through the substrate, and wherein the chamber is to initiate an isotropic etch immediately following termination of an anisotropic etch. 
     
     
         5 . The system of  claim 4 , wherein the chamber is to initiate the isotropic etch while the substrate is heated to a temperature of 80-100° C. 
     
     
         6 . The system of  claim 1 , wherein the anisotropic plasma etch module is to perform iterations of a cyclic process including polymer deposition, directional bombardment etch, and isotropic chemical etch, until a back side tape is exposed at the bottom of an etched trench; and
 wherein the isotropic plasma etch module is configured to employ a non-polymerizing fluorine or chlorine-based chemistry source.   
     
     
         7 . The system of  claim 4 , wherein the non-polymerizing fluorine or chlorine-based chemistry consists essentially of NF 3  or SF 6 , Cl 2  or SiF 4 . 
     
     
         8 . The system of  claim 4 , wherein the non-polymerizing fluorine or chlorine-based chemistry further includes an oxidizer. 
     
     
         9 . The system of  claim 1 , wherein the isotropic plasma etch module is configured to perform the isotropic etch for less than 90 seconds. 
     
     
         10 . The system of  claim 1 , further comprising a deposition module to form the mask above the substrate, the mask covering and protecting the integrated circuits. 
     
     
         11 . A system for dicing a substrate comprising a plurality of integrated circuits (ICs), the system comprising:
 a laser scribe module to pattern a mask to form a trench exposing regions of the substrate between the ICs;   an anisotropic plasma etch module physically coupled to the laser scribe module to anisotropically etch completely through the substrate to singulate the integrated circuits;   an isotropic etch module to perform an isotropic etch of a trench following singulation; and   a robotic transfer chamber to transfer the laser scribed substrate from the laser scribe module to the anisotropic plasma etch module.   
     
     
         12 . The system of  claim 1 , wherein the laser scribe module comprises a femtosecond laser having a wavelength less than or equal to 540 nanometers and a pulse width of less than or equal to 400 femtoseconds. 
     
     
         13 . The system of  claim 1 , wherein the isotropic plasma etch module and the anisotropic plasma etch module are a same, single chamber. 
     
     
         14 . The system of  claim 13 , wherein the anisotropic etch etches completely through the substrate, and wherein the chamber is to initiate an isotropic etch immediately following termination of an anisotropic etch. 
     
     
         15 . The system of  claim 14 , wherein the chamber is to initiate the isotropic etch while the substrate is heated to a temperature of 80-100° C. 
     
     
         16 . The system of  claim 11 , wherein the anisotropic plasma etch module is to perform iterations of a cyclic process including polymer deposition, directional bombardment etch, and isotropic chemical etch, until a back side tape is exposed at the bottom of the etched trench; and
 wherein the isotropic etch module is configured to employ a non-polymerizing fluorine or chlorine-based chemistry source.   
     
     
         17 . The system of  claim 11 , wherein the anisotropic plasma etch module is to perform iterations of a cyclic process including polymer deposition, directional bombardment etch, and isotropic chemical etch, until a back side tape is exposed at the bottom of the etched trench; and
 wherein the isotropic etch module comprises a wet chemical etch module.   
     
     
         18 . The system of  claim 1 , wherein the isotropic plasma etch module is configured to perform the isotropic etch for less than 90 seconds. 
     
     
         19 . A system for dicing a substrate comprising a plurality of integrated circuits (ICs), the system comprising:
 a laser scribe module to pattern a mask to form a trench exposing regions of the substrate between the ICs, wherein the laser scribe module comprises a femtosecond laser having a wavelength in a range of 250 to 540 nanometers and a pulse width in a second range of 100 to 400 femtoseconds;   an anisotropic plasma etch module physically coupled to the laser scribe module to anisotropically etch completely through the substrate to singulate the integrated circuits; and   an isotropic etch module to perform an isotropic etch of a trench following singulation.   
     
     
         20 . The system of  claim 19 , wherein the isotropic etch module and the anisotropic plasma etch module are a same, single chamber.