Patent ID: 7348199

Claim:
A method of dividing a wafer having function elements formed in areas sectioned by dividing lines formed in a lattice pattern on the front surface, into individual chips along the dividing lines, comprising: a deteriorated layer forming step for forming a deteriorated layer along the dividing lines in the inside of the wafer by applying a laser beam capable of passing through the wafer along the dividing lines, from the back surface side of the wafer; a wafer supporting step for putting the back surface of the wafer in which the deteriorated layer has been formed along the dividing lines, on an extensible support tape mounted on an annular frame; and a dividing step for dividing the wafer along the dividing lines in which the deteriorated layer has been formed, by expanding the support tape affixed to the wafer, wherein the dividing step is to first divide the wafer along dividing lines extending in a predetermined direction and subsequently, along dividing lines extending in a direction intersecting with the predetermined direction by expanding the support tape such that tensile force acting in a direction perpendicular to the dividing lines extending in the predetermined direction becomes larger than tensile force acting in a direction perpendicular to the dividing lines extending in the direction intersecting with the predetermined direction, when the supporting tape affixed to the wafer is expanded.