Abstract: A thermal treatment boat having a plurality of annular, coaxial, spaced apart bands having substantially the same inner diameters. The bands are separated by a band spacing distance of from about 3.8 to 12.7 mm, each of the bands having a height, Height.sub.Band, in mm according to the equation: ##EQU1## wherein Height.sub.Band is always.gtoreq.wafer thickness; ColumnHeight is the total height of the treatment boat, mm; BandSpacing is the band spacing distance between adjacent bands, mm; and NumberBands is the total number of bands in the treatment boat. Preferably the NumberBands is from about 12 to about 100. Each band includes wafer support means for supporting a wafer therein at a position which is substantially centered between the upper edge surface and said lower edge surface thereof, the wafer support means in one embodiment including at least three inwardly extending projections.

Abstract: Process for treating multiple parallel wafers positioned in a heating zone surrounded by a heater emitting radiant heat. A space of from 0.5 to 2.55 cm is maintained between each wafer, and the outer portions of each wafer are shielded from radiant heat emitted by the heater by means of a circular heat shield positioned between the outer edge of the wafer and the heater. The circular heat shield has an upper edge and a bottom edge, and is positioned at a distance of less than 0.5 cm from the outer edge of the wafer. The wafer is positioned to be substantially centered between said upper edge and said bottom edge of its respective heat shield, and the circular heat shield has a height of from 0.35 to 0.95. The heat provided by the heater can be sufficient to raise the temperature of the wafers from 21.degree. C. up to 1100.degree. C. at a rate of 100.degree. C./min without causing thermal stress damage to the wafers.