Materials Research Corporation

Sony Corporation

Charles Van Nutt

Steven D Hurwitt

Israel Wagner

Robert G Hieronymi

Richard C Edwards

Arnold J Aronson

Donald A Messina

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.

Method of pretexturing a cathode sputtering target and sputter coating

A plasma confining magnetic field is generated over the sputtering region of a sputtering target with a critical field line which determines the shape of the plasma. The critical field line is progressively flattened over the course of the life of the target as the target erodes. Preferably, the magnet is configured with poles spaced around the portion of the target below the sputtering region to provide a magnetic field that flattens as its strength decreases. A regulated power supply maintains a regulated power level that is increased as the target erodes to maintain a constant deposition rate. The voltage delivered by the power supply is maintained at or above a constant level by progressively decreasing the current to an electromagnet to progressively reduce the field strength and flatten the field. As a result of the invention, the erosion groove of the target is broadened and the number of wafers coated by the target during its life is increased.

Method of enhancing the performance of a magnetron sputtering target

A sputter coating apparatus displays set and alternative machine parameters, entered or calculated from entered or measured data, for selection by the operator. The apparatus performs a sputter coating process to produce sputter coated articles in accordance with the selected machine parameters. Process parameters familiar to the person creating the process, such as desired coating thickness and desired deposition rate, may be entered by the operator. Measured data such as actual coating thickness at a plurality of points on a previously processed wafer may be entered by an operator or automatically measured from a wafer. Alternative machine parameters such as target sputtering power may be entered by an operator or calculated from entered process parameters or measured data. The operator selects and initiates a process in accordance with the selections by entering commands. The machine parameters control separately the sputtering from different regions of the sputtering surface of a one piece sputtering target by alternately energizing different plasmas over the different target regions and energizing the target in accordance with different machine parameters.

Sputter coating process control method and apparatus

A magnetron sputtering method and apparatus employing a one-piece annular target having a concave continuously smooth surface with an inwardly facing portion close to and surrounding the outer edge of a stepped wafer provides a sputtering surface with areas facing the differently facing surfaces of the wafer steps. Two concentric erosion zones on the target surface are independently energized at different electrical parameter values by synchronizing the power applied to the single target with switched activation of plasmas overlying the respective target regions which define the erosion zones. The electrical parameters and the geometry are established so as to uniformly coat the differently facing surfaces of the stepped wafer. During part of the duty cycle during which each target region is energized, parameters may be measured. Such parameters may be those which vary with changes in geometry as for example may be due to target erosion. The operation of different target regions, such as the duty cycles or power levels for such regions, may be separately varied in response to the measurements or otherwise, to maintain uniform substrate coating as the target erodes. The target is thicker under the outer region and has an annular pole piece embedded to reduce the space separating the target erosion regions, and includes means to cool the target and reinforce it against thermal expansion.

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Monroe, NY, United States of America

Charles Van Nutt