Fusing silicon water to glass backing plate - using high voltage and applied heat to secure silicon waters and ultra-thin membranes to glass backing plate

The unit is enclosed within a protective hood (20) and comprises a lower holder/electrode supported by a heating plate (17) and featuring three polished concentric depressions, the first to hold the glass backing plate, the second to hold the silicon wafer and a third to prevent damage to the upper face of the wafer, and an upper cover/electrode, mounted on a supporting arm (7) and comprising a cover plate (5), a central guide post (6) and an upper restraining plate (9). The cover plate is insulated (8) from the hydraulically-operated supporting arm and features a concentric separation mass (12) with pegs (13) that protrude through the cover plate. In operation, the silicon wafer and backing plate are placed in the heated lower holder/electrode and the hydraulically operated supporting arm lowered, pressing the upper cover/electrode against the backing plate. A voltage (19) is then applied across the upper cover/electrode and the lower holder/electrode, fusing the silicon wafer to the backing plate. The supporting arm is then lifted and the weight of the separation mass acting via the associated pegs ensure that the wafer separates from the upper cover/electrode. USE/ADVANTAGE - For making X-ray masks. Reduced setting time and contamination risk when compared to adhesive bonding.