PURPOSE: To provide the box body having the inside shape of a bonded part to which impurity is hard to adhere at the time of washing.
CONSTITUTION: The box body B of a vacuum chamber has a top plate l, a bottom plate 2, side plates 3a-3d and the plates 12 welded to the stepped parts 11 formed to the inside surfaces of the bonded parts between four side plates 3a, 3b, 3c, 3d so that the cross sections in the lateral direction thereof have a circular arc of R-100mm of a 1/4 circular arc. In the vacuum chamber of a semiconductor producing device using the box body B, washing during the production of a semiconductor becomes easy and the adhesion of impurity to the inside circular arc surfaces of the bonded parts due to process gas is eliminated and the inferiority of a super-LSI requiring especially severe quality can be reduced to a large extent. Further, a washing time is shortened and washing cost is reduced.
NOSE SHIRO
FUKUNAGA AKIO
ONISHI KEITA
