Package substrate dividing method

A package substrate dividing method for dividing a package substrate into a plurality of device packages in a condition where an ultraviolet curing type adhesive tape is attached to a back side of said package substrate, by holding said package substrate through said adhesive tape on a chuck table and cutting said package substrate along a plurality of division lines formed on a front side of said package substrate, said package substrate including a device portion partitioned into a plurality of device package regions by said division lines and a marginal portion surrounding said device portion, said package substrate dividing method comprising:

• a first ultraviolet light applying step of applying ultraviolet light to said adhesive tape in a condition where a first area of said adhesive tape corresponding to said marginal portion is exposed and a second area of said adhesive tape corresponding to said device portion is masked by a mask member, thereby reducing an adhesive force of said adhesive tape in said first area corresponding to said marginal portion;
• a partial peeling step of partially peeling said adhesive tape from said package substrate in said first area corresponding to said marginal portion after performing said first ultraviolet light applying step;
• and
• a dividing step of cutting said package substrate along each division line by using a cutting blade set at a height where said adhesive tape attached to the back side of said package substrate is cut by said cutting blade, thereby dividing said package substrate into said device packages after performing said partial peeling step;
• wherein in said dividing step, said marginal portion separated from said package substrate is scattered by a rotation of said cutting blade and thereby removed from said adhesive tape.