Abstract: A planetary evaporator having at least one source of material for coating, by evaporation, workpieces such as semiconductor wafers. The apparatus includes a pallet mounted for rotation about its own axis, and substrate or workpiece holders mounted on the pallet which orbit said axis. Guides support the pallets and a cam follower on the pallet follows a cam to effect reciprocation of the pallet as it rotates, the guides being adapted for rotation about another axis which is substantially perpendicular to the axis of rotation of the pallet. In another embodiment the substrate holders are also rotated so as to give four degrees of freedom of the workpiece or substrate relative to the material source.