Recent progress in semiconductor devices has been remarkable. With the appearance of VLSI, production of devices has shifted from the 64K bit to the 256K bit. Reductions in size on the microfabrication have been achieved, from 2.5 μm for the 64K bit to 2.0 μm for the 256K bit. For 1 mega bit devices, further reduction to 1 μm has approached the limit for photoresist fabrication. Submicron fabrication will require special processing techniques.
The following is a brief explanation of high resolution resists, including photoresist, Deep UV resist, electron beam resist, X-ray resist, and plasma-developable resist.