Abstract: In a semiconductor device, an average grain size of a filler contained in an adhesive agent applied to the first chip is larger than an interval between adjacent wires. When the second chip is pressed downward, the filler is caught between the wires, a larger number of filler grains is held between the first and second chip. The interval between the first and the second chip can be stably maintained. Since the number of filler grains left to be held between the first and second chip is larger than that in the conventional art, a pressure applied to the second chip is uniformly distributed while suppressing the number of filler grains contained in the adhesive agent from increasing, and a pressure applied to the grains is lower than that in the conventional art.