Abstract: A press-forming die set including a first die and a second die which are linearly movable in a press-forming direction for mutual engagement to form a negative-angle portion on a workpiece placed on the second die, the press-forming die further including a rotary cam having a first negative-angle forming portion, and a forming cam having a second negative-angle forming portion. The first negative-angle forming portion is disposed such that the rotary cam is rotatable about an axis of rotation inclined with respect to a bottom surface of the workpiece. The rotary cam is engageable with the second die and is rotated about the axis of rotation in one of opposite directions when the first and second dies are moved toward each other, and is rotated in the other direction when the first and second dies are moved away from each other.

Abstract: A plurality of strip shaped first polysilicon layers 3 are formed on a monocrystalline silicon substrate 1, a plurality of strip shaped second polysilicon layers 5 are formed thereon crossing the first polysilicon layers 3, and a plurality of strip shaped third polysilicon layers 8 are further formed thereon crossing the second polysilicon layers 5. The first and second polysilicon layers 3 and 5 are laser-annealed and monocrystallined. Contact holes 4 and 7 are selectively formed at the crossing points of the first polysilicon layers 3 and the second polysilicon layers 5, and the crossing points of the second polysilicon layers 5 and the third polysilicon layers 8. A PN junction is formed on each surface layer of the first polysilicon layers 3 and the second polysilicon layers 5 in the portions corresponding to these contact holes 4 and 7. Two layers of memory cell arrays using diode elements as memory cells are piled upon each other.