The present invention provides a highly controllable device for exposure
from the back side and an exposure method, and also provides a method of
manufacturing a semiconductor device using the same. The present
invention involves exposure with the use of the back side exposure device
of which a reflecting means is disposed on the front side of a substrate,
apart from a photosensitive thin film surface by a distance X (X=0.1
.mu.m to 1000 .mu.m), and formation of a photosensitive thin film pattern
in a self alignment manner, with good controllability, at a position a
distance Y away from the end of a pattern. The invention fabricates a TFT
using that method.