CASSETTE FOR DIFFUSION TREATMENT OF SEMICONDUCTOR WAFERS Russian patent published in 2011 - IPC H01L21/22 

FIELD: physics.

SUBSTANCE: cassette for diffusion treatment of semiconductor wafers has four parallel cylindrical rods with grooves. The top rod acts as the cover and its opposite butt-ends can be fastened after putting the wafers into the cassette. The bottom rod acts as the bottom of the cassette and grooves in both rods have a flat-topped cross-section. The rods are made from undoped polycrystalline silicon. The depth of grooves in all rods is half the diameter of the rods. The rods are placed such that the transverse plane of their cross-section is perpendicular to their longitudinal axes, and the cross-section of each rod has the shape of a circle. The diameter of the cylindrical rods is equal to 0.8-1.2 cm. Lateral rods and the bottom rod are placed relative each other and the semiconductor wafers such that the centre of each circle in the plane of the cross-section of the rods lies at the corners of a regular pentagon inscribed in the circle, the diameter of which is equal to the diameter of the semiconductor wafers, wherein said corners lie in the bottom half of the circle. The width of the grooves in the lateral rods is greater than the thickness of the treated wafers by 60-100%.

EFFECT: preventing loss of wafers during diffusion thermal treatment.