Method of laser processing for substrate cleaving or dicing through forming "spike-like" shaped damage structures

A laser processing method for substrate cleaving or dicing comprising

• a step of irradiating a workpiece with a pulsed laser beam, through;
• wherein laser pulses are delivered on to the surface of the workpiece for cleaving;
• wherein workpiece means an object to be cleaved or diced with at least one flat surface;
• wherein workpiece is transparent for the laser radiation;
• wherein sequence of damaged zones produce a cleaving plane;
• wherein produced cleaving plane enables easy breaking along desired line of substrate separation, wherein the processing method comprises steps of:
• modifying said laser beam with a beam focusing unit arranged to focus the laser beam into the bulk of the workpiece material, in such a way that the above workpiece bulk material optical damage threshold fluence distribution follows a “spike”-like shape,
• wherein beam focusing unit comprises at least one beam focusing element having high numerical aperture in the range of 0.5-0.9 NA,
• wherein the length of the “spike”-like shape fluence distribution is greater than its transverse dimension;
• producing a series of damage structures the shape of said “spike”-like shape fluence distribution, along the intended cleaving plane, while maintaining the distance between said beam focusing unit and first workpiece surface with means of maintaining distance.