Abstract: A vestibule block or interior furnace wall utilized in a diffusion furnace for manufacturing semi-conductors, integrated circuits and the like, and which is made of refractory or ceramic material, is treated on its surface with a suspension of fine particulate of a glass frit composition comprising an alkali earth metal alumino silicate, and is thereafter heated above the transition temperature of the alkali earth metal alumino silicate. Vestibule blocks and interior surface walls which have been treated in the above-described manner are highly abrasion resistant on their surface, generate virtually no particulate matter under conditions of ordinary use in the semi-conductor manufacturing processes, and generate significantly less particulate matter when tested in an abrasion test against vestibule blocks of the prior art.

Abstract: A collar for supporting and positioning a diffusion tube in a furnace used in the manufacture of semiconductors, integrated circuits and the like, is disclosed. The collar has a resilient core and an outer cover enclosing the core. The core and the cover are made of materials which readily withstand the normal operating temperatures of the furnace. The collar is dimensioned to tightly fit around a circumference of the diffusion tube, and to fit within an aperture provided in a support block of the furnace. The collar permits precise positioning of the diffusion tube relative to a helical heating coil provided in the furnace.