Method of pretexturing a cathode sputtering target and sputter coating an article therewith
AssigneesSony Corporation, Materials Research Corporation
InventorsSteven D. Hurwitt, Charles Van Nutt
Life of this patent
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Abstract
A sputtering target is pretextured, prior to being subjected to the initial sputter precleaning and use in a sputter processing apparatus, by artificially roughening the sputtering surface of the target to produce a texture which functions, when used in the sputter coating of substrates, in a manner equivalent to the surface of a target roughened by an hour or more of a sputter burn-in process. The surface is textured by the machining of grooves or other irregular microstructure therein, by chemical etching, by mechanical abrading, or by another means other than sputter processing. A 0.05 to 3.0 millimeter texture size such as achieved with annular V-grooves 0.025 inches deep and spaced at 0.0625 inches is preferred.
Claims12
A method of limiting the variation of the voltage of a sputtering target, and of limiting the sputter burn-in time of a sputtering target that is necessary before operating the target at an operating voltage and using the target in a sputter coating process in a vacuum processing chamber of a cathode sputtering apparatus for the productive deposition of a film onto semiconductor wafers, said method comprising the steps of:
- fabricating a sputtering target while maintaining the target in an atmospheric pressure environment by:
- forming the target from sputtering material to provide a sputtering surface thereon having a predetermined macroscopic shape, and
- after forming the target and before exposing the target to a sputtering process, roughening the sputtering surface to create a microtexture thereon sufficiently smooth to avoid altering the macroscopic shape of the sputtering surface and having width and depth dimensions of at least approximately 0.05 millimeters;
- after the fabricating of the target, maintaining the sputtering surface of the target in unsputtered condition, and, before sputtering therefrom, mounting and sealing the target in a sputter coating chamber of a sputter coating apparatus and maintaining a gas at a vacuum pressure level into the chamber;
- energizing the unsputtered target so mounted and sealed in said chamber to a preconditioning voltage that is higher than the operating voltage but is not more than approximately 140% of the operating voltage during the first three hours of productive deposition of a film onto semiconductor wafers, and sputtering the target for not more than approximately one hour before introducing a wafer into the chamber and sputtering a commercially useful film onto a wafer from the target;
- then
- after not more than approximately one hour of sputtering at the preconditioning voltage, introducing a wafer into the chamber and energizing the target to the operating voltage, and sputtering a film onto the wafer from the sputtering target.
A method of limiting the variation of the voltage of a sputtering target, and of limiting the sputter burn-in time of a sputtering target that is necessary before operating the target at an operating voltage and using the target in a sputter coating process in a vacuum processing chamber of a cathode sputtering apparatus for the productive deposition of a film onto semiconductor wafers, said method comprising the steps of:
- fabricating a sputtering target while maintaining the target in an atmospheric pressure environment by:
- forming the target from sputtering material to provide a sputtering surface thereon having a predetermined macroscopic shape, and
- after forming the target and before exposing the target to a sputtering process, roughening the sputtering surface to create a microtexture thereon sufficiently smooth to avoid altering the macroscopic shape of the sputtering surface and having width and depth dimensions of at least approximately 0.05 millimeters;
- after the fabricating of the target, maintaining the sputtering surface of the target in unsputtered condition, and, before sputtering therefrom, mounting and sealing the target in a sputter coating chamber of a sputter coating apparatus and maintaining a gas at a vacuum pressure level into the chamber;
- energizing the unsputtered target so mounted and sealed in said chamber to a preconditioning voltage, before commercially useful films are sputtered onto a substantial number of wafers from the target, removing by sputtering the microtexture created by the surface roughening step;
- then
- sputtering a commercially useful film onto a substantial number of wafers in the vacuum chamber from the sputtering target.
Dependencies are inferred from the claim text.