Method of manufacturing semiconductor device in which bottom surface and side surface of semiconductor substrate are covered with resin protective film

A semiconductor device manufacturing method comprising:

• preparing an assembly having an insulating film formed on one surface of a semiconductor wafer where an integrated circuit is formed, an interconnect formed on the insulating film in such a manner as to be connected to the integrated circuit, an external connection bump electrode formed on the electrode connection pad portion of the interconnect, and a sealing film formed around the external connection bump electrode;
• affixing a support plate having a large number of pores to the external connection bump electrode and the sealing film via an adhesive layer;
• forming a trench reaching an intermediate position of the thickness of the sealing film on the bottom side of the semiconductor wafer in parts corresponding to a dicing street and both sides thereof;
• forming a resin protective film on the bottom surface of the semiconductor wafer including the inner part of the trench;
• infiltrating a detachment solution from the pores in the support plate to dissolve and remove the adhesive layer, and thereby separating the support plate from the external connection bump electrode and the sealing film;
• and
• cutting the sealing film and the resin protective film in a width smaller than the width of the trench.