METHOD OF SINGULATING A THIN SEMICONDUCTOR WAFER

METHOD OF SINGULATING A THIN SEMICONDUCTOR WAFER AbstractA method of singulating a semiconductor wafer by partitioning it along a network of scribelines, the wafer having two substantially parallel major surfaces that are separated from one another by a thickness T < 200 µm, said scribelines extending along a first of said major surfaces, which method comprises the following steps:adhering the second major surface of the wafer to an elastic foil, which is clamped to a wafer table so as to present the first major surface to a radiative scribing tool;using the radiative scribing tool to produce at least one pulsed laser beam having a pulse duration P < 75 ps;causing said laser beam to scan along each of said scribelines so as to create a radiative scribe with a depth D < T, thereby leaving the second major surface intact;laterally stretching said foil so as to sever the second major surface along the path of said radiative scribes.Preferentially, P < Cpp, in which Cpp is the Time Constant of phonon-phonon coupling in the wafer at the location of incidence of the laser beam. A typical value for F= T-D lies in the range 5-50 um, for example in the range 10-30 um.[Figs. 2 and 3]