Importance

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Abstract

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

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First Claim