MANUFACTURE OF SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To improve reliability and productivity while maintaining thermal stress relaxation function by preparing a mask which forms a desired opening part in a place whereon a semiconductor chip of a flexible board is mounted, injecting elastomer to an opening part and raising a temperature of a heating medium provided near an opening part. SOLUTION: A mask with an opening part in a desired place such as a mold plate 20 is mounted on a flexible board 2 such as a TAB tape. After gel-like elastomer 4 is injected to an opening part, a side edge face 4a of the elastomer 4 is heated by a heating medium 100 provided near an opening part H of the mold plate 20 and a side edge face is hardened or set. Thereafter, a semiconductor chip is mounted on elastomer and cured or a semiconductor chip is mounted after curing. It is possible to form an elastomer layer whose side edge face is in a straight position at high producibility while maintaining thermal stress relaxation function which is an original function of elastomer.