Varian Associates, Inc.

David J Harra

Frederick T Turner

Martin A Hutchinson

Charles B Garrett

William C Nystrom

Kenneth F Freeman

Larry D Hartsough

Lawrence C Lei

A magnetron sputter apparatus is disclosed which includes a rotatable generally heart-shaped, closed-loop magnet array behind the target and in front of a pair of separately driven stationary electromagnets. The apparatus is optimized to produce a sputtered film on a planar substrate having desired film characteristics such as uniformity of thickness, good step coverage, and good via filling and efficient utilization of the target. The shape of the generally heart-shaped array includes a flattened tip forming an arc of a circle centered on the axis of rotation and concave cusps in the lobes of the heart-shape. The electromagnets are used to increase target utilization at its center and to compensate for the change in shape of the target and distance from the target to the substrate with depletion.

Sputtering apparatus having a rotating magnet array and fixed

A rotatable magnet configuration for use in a magnetron sputtering system for obtaining a desired sputter target erosion profile and for obtaining a sputtered film on a substrate having a desired film characteristic, such as uniformity of thickness, and a method of designing such a magnet configuration are disclosed. The disclosed design and method compensate for the discrepancy between the between the actual position of the magnet and the 'effective' position of the magnet as measured by a static erosion profile obtained holding the magnet stationary. The method shown describes how to adjust the actual shape of the magnet to obtain a desired effective shape that will produce a predetermined erosion profile in the sputter target. In addition, the disclosure describes how to determine an optimal erosion profile to produce a sputtered film having a desired characteristic.

Sputtering apparatus with a magnet array having a geometry for a

A planar magnetron sputtering device has an extended flat circular target source in opposed spaced parallel relationship with a generally flat article to be coated, placed within an evacuated coating chamber. Crossed electric and magnetic fields in the chamber are established in order to set up a plasma adjacent the target. The magnetic field is provided by a magnetic assembly of permanent magnets on the non-vacuum side of the target. The magnetic assembly is smaller in diameter than the target, but is mounted to a means for moving the assembly laterally over the entire area of the target. This means for moving sweeps the magnetic assembly in an eccentric path generally centered on the target center, with the path being non-reentrant and precessing about the target center with time. In this manner, the path sweeps different areas on successive rotations about the center, and a given area of target is exposed to the magnetic field at many successively different orientations. Articles are therefore coated with significantly improved uniformity and step coverage, while utilization of target material is improved.

Planar magnetron sputtering device with combined circumferential and

An apparatus for the uniform thermal treatment of semiconductor wafers by gas conduction holds the wafer in place over a gas filled cavity in opposition to a thermal mass maintained at an appropriate temperature. Gas is introduced behind the semiconductor wafer adjacent its periphery to produce a near-constant gas pressure across the backside of the wafer. The constant pressure produces constant thermal conductivity. Consequently, heat conduction is uniform, the temperature of the wafer is uniform and uniform processing is accomplished across the wafer.

Apparatus for thermal treatment of semiconductor wafers by gas

A method of sputter depositing a desired film thickness profile on a substrate is accomplished by depositing material onto a substrate at spaced apart coating stations whereby a substrate at any of said stations is not coated by the sputter coating action at any of the other sputter stations. The substrate is held stationary during complete sputtering at each station. A blocking shield is placed in fixed position between the substrate and the sputter coating source at one or more of the stations. The duration of sputter coating time at one station may be different than at another station.

Blocking shield and method for contouring the thickness of sputter

The arbitrary contouring of thickness of a sputter-deposited film is made possible by a blocking means having a primary blocking shield and an ancillary blocking shield. The primary blocking shield intercepts atoms sputtered directly from the cathode target by line-of-sight transport. The ancillary blocking shield extends downwardly from the side of the primary blocking shield which is placed closest to the substrate. The ancillary blocking shield intercepts atoms sputtered from the cathode which by intervening gas collisions have been redirected to travel underneath the primary blocking shield. Precise tailoring of the thickness profile of the coating on the substrate is thereby provided and the quality of the composite film is maintained. The method for contouring the thickness of sputter coated layers comprises sputter coating portions of the film at successive stations. By employing the improved blocking shield at selected stations, the film in the aggregate may have the desired thickness contour.

Sputter system incorporating an improved blocking shield for contouring

A method for etching a semiconductor wafer on an RF etch table employs a succession of different biases on an extension member positioned adjacent the periphery of the table. The extension member is electrically conductive, but is insulated from the etch table. The extension member is positioned with respect to the periphery of the table in a manner such that the plasma sheath induced above the etch table is continued beyond the periphery of the table, thereby eliminating the focusing of ions on the edges of an item being etched on the table. As different bias voltages are applied to the extension member, different etch profiles are experienced on the semiconductor wafer. The aggregation of etch profiles produces a more uniform overall etch.

Method for obtaining uniform etch by modulating bias on extension member

An RF etch table has a biased extension member positioned adjacent its periphery. The extension member is electrically conductive, but is insulated from other conductive members in the system. The extension member is positioned with respect to the periphery of the table in a manner such that the boundary of the plasma induced above the etch table is continued beyond the periphery of the etch table, thereby eliminating the focusing of ions onto the edges of an item being etched on the table. The potential impressed upon the extension member produces a dark space above its surface having a sufficient height so that the horizontal configuration of the sheath above the etch table is continued beyond its edges. More uniform etching is accomplished.

Radio frequency etch table with biased extension member

An all-metal joint is provided wherein a metal gasket disposed between mating flanges can readily be removed when the joint is disassembled. Opposing faces of the mating flanges are configured to provide a recess between the flanges in which a soft metal gasket of annular configuration can be received when the flanges are coupled together. Symmetrically disposed ridges on the opposing flange faces penetrate into a peripheral region of the gasket, thereby causing a portion of the gasket material to flow into an annular groove that forms the periphery of the recess between the opposing flange faces. This compressed material in the annular groove provides a gas-tight seal between the mating flanges. The configuration of the opposing flange faces is such that when the joint is dissassembled, the net force tending to retain the gasket in position against either one of the flange faces is minimized. In particular, each flange face is configured so that the residual compressive forces present when the flange coupling mechanism is released, distributed over the surface of the gasket, are in net effect substantially equal to or greater than the frictional and bonding forces that might tend to retain the gasket in contact with either flange. In this way, the gasket tends to break away from the mating flange faces when the joint is disassembled.

Growing community of inventors

Santa Cruz, CA, United States of America

David J Harra