EFFECT OF PROCESS PARAMETERS ON GLOW-DISCHARGE AND FILM THICKNESS UNIFORMITY IN FACING TARGET SPUTTERING

The design details of a facing target sputtering system are presented. The influence of geometric parameters of the system such as target si ze, inter-target distance and target-to-substrate distance on the plas ma discharge current and floating potential have been investigated. Al so, the effect of deposition parameters, namely cathode voltage and sp uttering pressure, on the plasma has been studied in detail. It has be en observed that the discharge current is very sensitive to the operat ing pressure in the range 10 to 1 Pa for the inter target distance bet ween 60 and 90 mm. The substrate floating potential decreased from 4 t o 3 V, when cathode voltage was increased from 100 to 1000 V. For an i ncrease of the target to substrate distance from 35 to 55 mm, the subs trate floating potential increased by 1 V. A comparison of the above r esults with that of d.c. diode sputtering has also been presented. The thickness profiles of the films deposited at different conditions hav e been measured. It indicates that a large uniform thick coating could be achieved at lower inter-target distance (50-60 mm) and higher pres sure (10 Pa).