| 摘要 |
<p>Damage to gallium arsenide substrate (27) during plasma ignition for PVD processing is avoided by virtual shutter, which provides functions without disadvantages of mechanical shutter to minimize density of high energy particles created during plasma ignition from reaching GaAs substrate. Plasma ignition process sequence uses high pressure gas ignition gas burst in combination with control of other parameters, such as (a) varying plasma ignition gas composition to include xenon, krypton or fluorinated molecular gases, (b) varying target-to-substrate distance to at least double distance during plasma ignition, (c) increasing magnetron magnetic field strength either permanently or during plasma ignition to about 400 Gauss, (d) preconditioning the target (24) by sputtering whenever system (10) has been idle for several minutes, (e) adjusting power supply (30) power ramping to the target (24) over 5-6 seconds or more, and/or (f) using simple electric circuit to drain charge build up on GaAs substrate (27).</p> |
