Patent ID: 7341926
Filing Date: 2008-03-11
Classification: B23K,B28D,H01L

Abstract:
1. A method of dividing a wafer having a plurality of first dividing lines and a plurality of second dividing lines perpendicular to the plurality of first dividing lines formed on the front surface and functional devices formed in a plurality of areas sectioned by the plurality of first dividing lines and the plurality of second dividing lines, into individual chips along the plurality of first dividing lines and the plurality of second dividing lines, comprising the steps of: a deteriorated layer forming step for applying a laser beam capable of passing through the wafer along the plurality of first dividing lines and the plurality of second dividing lines to form a deteriorated layer in the inside of the wafer along the plurality of first dividing lines and the plurality of second dividing lines; an expansion sheet affixing step for putting the wafer on the surface of an expandable expansion sheet having an adhesive which is cured by applying an external stimulus to the surface before or after the above deteriorated layer forming step; a first sheet expanding step for dividing the wafer into a plurality of belt-like pieces along the plurality of first dividing lines in which the deteriorated layer has been formed, by expanding the expansion sheet in direction perpendicular to the plurality of first dividing lines and forming a space between adjacent belt-like pieces; an adhesive curing step for curing the adhesive by applying an external stimulus to the adhesive laid on the expansion sheet through the spaces between adjacent belt-like pieces; and a second sheet expanding step for dividing the wafer which has been divided into the plurality of belt-like pieces along the plurality of second dividing lines in which the deteriorated layer has been formed, by expanding the expansion sheet in direction perpendicular to the plurality of second dividing lines after the above adhesive curing step.