Method for measuring and controlling beam current in ion beam processing
AssigneeThe Regents of the University of California
InventorsPatrick A. Kearney, Scott C. Burkhart
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Abstract
A method for producing film thickness control of ion beam sputter deposition films. Great improvements in film thickness control is accomplished by keeping the total current supplied to both the beam and suppressor grids of a radio frequency (RF) in beam source constant, rather than just the current supplied to the beam grid. By controlling both currents, using this method, deposition rates are more stable, and this allows the deposition of layers with extremely well controlled thicknesses to about 0.1%. The method is carried out by calculating deposition rates based on the total of the suppressor and beam currents and maintaining the total current constant by adjusting RF power which gives more consistent values.
Claims8
A method for controlling thickness of a film formed by ion beam sputter deposition, comprising:
- supplying a constant sum of beam grid current and
- suppressor grid current, and
- wherein supplying the constant sum of beam grid and suppressor grid currents is carried out by adjusting the plasma density.
In a method for controlling the deposition rate of a film formed by an RF ion beam gun having a beam grid, a suppressor grid and a ground grid, the improvement comprising:
- keeping the total current supplied to both the beam and suppressor grids constant by adjusting the RF power.
In an RF ion beam source having a beam grid, a suppressor grid, and a ground grid, the improvement comprising:
- means for measuring the current supplied to the beam grid and the suppressor grid, and
- means for keeping the total current supplied to the beam and suppressor grids constant which includes means for adjusting RF power.
Dependencies are inferred from the claim text.