Process of Free Polishing Semiconductor Wafers
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-07
More consistently flat semiconductor wafers can be produced by this two-step free polishing method utilizing hard pads to achieve better flatness. Free polishing as normally practiced in the semiconductor technology is a single-step process for generating smooth, highly specular, damage-free surfaces. Relatively soft poromeric polishing pads are used for this purpose. In this improved process, a flatter surface on the semiconductor wafers can be generated using a two-step process. In the first stage of the two-step free polishing process, hard, flat, highly dense materials are used on the top and bottom platens of the free polishing machines. Typically, such pad materials use blown polyurethanes or rosin-impregnated synthetic felts.