Abstract: A shield for controlling film thickness is arranged between a substrate and a target. The shield includes an aperture being narrow at a target side and wide at a side opposite to the target. Since the density of sputtered particles decreases away from the target, a portion of the substrate that is far from the target is exposed to low-density sputtered particles for a long time, and a portion of the substrate that is near the target is exposed to high-density sputtered particles for a short time, whereby a film of even thickness distribution is formed on a deposition face of the substrate.

Abstract: A non-asbestos friction material is made of a molded and cured composition comprising a fibrous base other than asbestos, a binder and a filler. The filler includes barium sulfate having an average particle size of 20 to 500 &mgr;m. Friction materials thus constituted can be endowed with a porosity of 5 to 25%. In addition, they have a good resistance to fade, a good coefficient of friction at high speed, and outstanding strength and wear resistance.