Method of dividing a wafer by back grinding

A wafer processing method for dividing a wafer into individual device chips along a plurality of crossing division lines, a front side of said wafer being partitioned by said division lines to define a plurality of separate regions where a plurality of devices corresponding to said device chips are formed, said wafer processing method comprising:

• a dividing groove forming step of forming a dividing groove along each division line formed on the front side of said wafer, said dividing groove having a depth corresponding to the finished thickness of each device chip;
• followed by
• a dividing step of providing a protective member on the front side of said wafer after performing said dividing groove forming step, and next thinning said wafer to expose said dividing groove to a back side of said wafer, thereby dividing said wafer into said individual device chips;
• followed by
• a die bonding resin film forming step of applying a liquid resin for die bonding to the back side of said wafer after performing said dividing step, and next solidifying said liquid resin applied to the back side of said wafer, thereby forming a die bonding resin film having a predetermined thickness on the back side of each device chip;
• followed by
• an isolating step of isolating each device chip from said wafer after performing said die bonding resin film forming step;
• said die bonding resin film forming step including
• a thin film layer forming step of spraying atomized liquid resin to the back side of said wafer by utilizing high-pressure air to thereby form a thin film layer on the back side of said wafer, and
• an external stimulus applying step of applying an external stimulus to said thin film layer to thereby solidify said thin film layer;
• said thin film layer forming step and said external stimulus applying step being repeated alternately two or more times to thereby form said die bonding resin film having said predetermined thickness;
• wherein the pressure of the high-pressure air and the amount of atomized liquid resin to be sprayed per unit of time is set so as to prevent entry of the liquid resin into the dividing grooves, in consideration of the width of each dividing groove and the viscosity of the liquid resin.