FIRST PROTECTIVE FILM FORMING SHEET

A first protective film forming sheet includes a first base member, a buffer layer formed on the first base member, and a curable resin film formed on the buffer layer, in which test pieces having a diameter of 8 mm and a thickness of 1 mm are prepared for the 2325 buffer layer and the curable resin film and the distortion is caused to occur on the test piece under the conditions of the temperature of 90°C and the frequency of 1 Hz so as to perform a distortion dispersion measurement for measuring the shear modulus G' of the test piece. At this time, a shear modulus Gb300' of the test piece of the buffer layer when the distortion of the test piece of the buffer layer is 300% and a shear modulus 2330 Gc300' of the test piece of the curable resin film when the distortion of the test piece of the curable resin film is 300% satisfy a relationship represented by Gb300' ≥ Gc300'. Fig. 3.