Abstract:
A substrate to be coated by RF sputtering is partially or completely surrounded by a target, which has a similarly shaped cathode surrounding and supporting the target. The target and the cathode may be formed of a pair of parallel plates or a hollow member. By controlling the pressure of the gas within the partially evacuated chamber in which at least the target is disposed and/or the spacing of the cathode plates or the size and geometrical configuration of the hollow member, a single common negative glow can be produced by either having the negative glow from the two parallel cathode plates overlap or touch each other or having a single negative glow within the hollow member.
Abstract:
THE OBJECT TO BE SPUTTER ETCHED IS EXCITED IN A REDUCED ATMOSPHERE OF INERT GAS BY AN ALTERNATION RF POTENTIAL WHICH IS SUPPLIED THROUGH A CAPACITIVE COUPLING CIRCUIT TO SET UP A GLOW DISCHARGE AROUND THE OBJECT. DURING THOSE PERIODS WHEN THE ALTERNATING RF POTENTIAL BIASES THE OBJECT ATTRACTS POSITIVE IONS TO PERFORM THIS SPUTTER ETCHING. DURING THE INTERVENING PERIOD, WHEN THE ALTERNATING RF POTENTIAL BIASES THE OBJECT POSITIVE, ELECTRONS ARE ATTRACTEDD TO THE TARGET. UNDER THESE CONDITIONS, SPUTTER ETCHING WILL CONTINUE WITHOUT THE ACCUMULATION OF A POSITIVE CHARGE AROUND THE OBJECT BEING ETCHED. THEREFORE, IS IT NOT NECESSARY TO MAINTAIN THE LARGE CODUCTIVE SURFACE AT A NEGATIVE POTENTIAL WITH AN ELECTRICAL CONNECTION TO AN OUTSIDE SOURCE OF ELECTRICAL ENERGY. EVEN MINUTE QUANITITES OF SUCH DIELECTRIC MATERIALS CAN BE REMOVED FROM SMALL CHEMICALLY ETCHED HOLES WHICH ARE TO ULTIMATELY BE LOCATIONS FOR ELECTRICAL CONTACTS TO SEMICONDUCTOR DEVICES.