Varian Associates, Inc.

Lawrence T Lamont, Jr

Martin A Hutchinson

Frederick T Turner

R Howard Shaw

Semiconductor wafers having patterns of steps and grooves defining microcircuit elements thereon are coated with metallic film by supporting the wafers individually adjacent a respective ring-shaped sputtering source in stationary relationship thereto. To effectuate such individual wafer processing on a continuous basis and preserve the evacuated argon environment, a vacuum chamber sputter coating apparatus is provided which has a number of work stations therein, at least one of which includes said ring-shaped sputtering source. Also included is a load lock, and an intermittently rotting vertical plate-like wafer carrier means therewithin positioned closely adjacent the chamber entrance, and carrying wafers in turn from the load lock to the work stations. The carrier includes apertures each accepting a wafer therewithin in an upright position, with the wafers edgewise resiliently supported by clip means, without the use of any externally-originating supports such as platens. Both surfaces of wafer can be accessed by processing equipment, for example, heating or cooling means at some of the work stations. Only a few wafers inside the chamber are at risk at any one time, and introduction of contaminants, debris, as well as disturbances to the chamber environment minimized.

Wafer coating system

Semiconductor wafers having patterns of steps and grooves defining microcircuit elements thereon are coated with metallic film by supporting the wafers individually adjacent a respective ring-shaped sputtering source in stationary relationship thereto. To effectuate such individual wafer processing on a continuous basis and preserve the evacuated argon environment, a vacuum chamber sputter coating apparatus is provided which has a number of work stations therein, at least one of which includes said ring-shaped sputtering source. Also included is a load lock; and an intermittently rotating vertical plate-like wafer carrier means therewithin positioned closely adjacent the chamber entrance, and carrying wafers in turn from the load lock to the work stations. The carrier includes apertures each accepting a wafer therewithin in an upright position, with the wafers edgewise resiliently supported by clip means, without the use of any externally-originating supports such as platens. Both surfaces of the wafer can be accessed by processing equipment, for example, heating or cooling means at some of the work stations. Only a few wafers inside the chamber are at risk at any one time, and introduction of contaminants, debris, as well as disturbances to the chamber environment are minimized.

In a vacuum chamber wafer treating apparatus, a wafer is heated or cooled by introducing a gas at a pressure of approximately 100 to 1000 microns in a region between the wafer and a heating element or heat sink. The gas conducts thermal energy between the wafer and heating element or heat sink.

Apparatus for thermal treatment of a wafer in an evacuated environment

Semiconductor wafers having patterns of steps and grooves defining microcircuit elements thereon are coated with metallic film by supporting the wafers individually adjacent a respective ring-shaped sputtering source in stationary relationship thereto. Within a short deposition time of approximately one minute, good uniformity of deposition across the main wafer plane is obtained by maintaining source-to-wafer spacing less than the diameter of the source, and an effective source diameter (D.sub.s) larger than the diameter of wafer (D.sub.w) with the coating being performed within an argon environment of 2 to 20 microns pressure. Good step coverage across all surfaces of steps and grooves is likewise obtained, and is further enhanced by confining the source-to-wafer spacing ranges to certain values within about 0.4 D.sub.s to 0.9 D.sub.s and the wafer diameter to certain values up to about 0.7 D.sub.s. To effectuate such individual wafer processing on a continuous basis and preserve the evacuated argon environment, a vacuum chamber sputter coating apparatus is provided which has a number of work stations therein, at least one of which includes said ring-shaped sputtering source. Also included is a load lock; and an intermittently rotating vertical plate-like wafer carrier means therewithin positioned closely adjacent the chamber entrance, and carrying wafers in turn from the load lock to the work stations. The carrier includes apertures each accepting a wafer therewithin in an upright position, with the wafers edgewise resiliently supported by clip means, without the use of any externally-originating supports such as platens. A closure member within the chamber is movable against the plate opposite the chamber entrance to close off the plate aperture from the chamber environment during loading and unloading of a wafer, and a door is provided to close the chamber opening and thus complete a thin low-volume load lock. The door is also provided with vacuum means to grasp a wafer presented vertically by a blade-like elevator which cooperates with a cassette and conveyor moving the cassette along a horizontal path below the chamber entrance. The cassette holds wafers vertically, and the blade passes therethrough to lift individual wafers edgewise to the door vacuum means. Closure of the door inserts the wafer into the clip means within the carrier and chamber, and the reverse operation extracts a wafer previously coated at a sputtering work station. Both surfaces of the wafer can be accessed by processing equipment, for example, heating or cooling means at some of the work stations. Only a few wafers inside the chamber are at risk at any one time, and introduction of contaminants, debris, as well as disturbances to the chamber environment are minimized.

In a vacuum chamber wafer treating apparatus a wafer is heated or cooled by introducing a gas at a pressure of approximately 100 to 1000 microns in a region between the wafer and a heating element or heat sink. The gas conducts thermal energy between the wafer and heating element or heat sink.

Method of thermal treatment of a wafer in an evacuated environment

Semiconductor wafers are coated with metallic film by supporting the wafers individually adjacent a ring-shaped sputtering source. A vacuum chamber sputter coating apparatus has a number of work stations therein, at least one of which includes the ring-shaped sputtering source. Also included is a load lock; and an intermittently rotating vertical plate-like wafer carrier therewithin positioned closely adjacent the chamber entrance, and carrying wafers in turn from the load lock to the work stations. The carrier includes apertures each accepting a wafer therewithin in an upright position, with the wafers edgewise resiliently supported by clips. A chamber door is provided with a vacuum chuck to grasp a wafer presented vertically by a blade-like elevator which cooperates with a cassette and conveyor moving the cassette along a horizontal path below the chamber entrance. Closure of the door inserts the wafer into the clips within the carrier and chamber, and the reverse operation extracts a wafer previously coated at a sputtering work station. Both surfaces of the wafer can be accessed by processing equipment, for example, for wafer heating or cooling at some of the work stations. Thermal transfer for wafer heating or cooling is accomplished by introducing a gas at a pressure of approximately 100 to 1000 microns in a region between the wafer and a heating element or heat sink. The gas conducts thermal energy between the wafer and the heating element or heat sink.

A circular magnetron sputter source employs a central anode surrounded by an annular cathode of generally inverted conical configuration. The anode structure forms a composite anode and inner magnetic pole piece which is operated at or near ground potential. An outer magnetic pole piece concentrically surrounds the annular cathode. This outer pole piece is electrically isolated from the cathode, and held at or near ground potential. The cathode is operated at a potential of several hundred volts negative with respect to ground. The cathode is held in place by a novel retainer means and has a novel cross section configuration. Magnetic flux is provided either by permanent magnets or by electromagnets or by a combination of both located externally of the vacuum chamber in which the sputter source is operated. Magnetic field lines pass from the outer pole piece and through the cathode, exiting the sputter surface near the outer edge of the cathode. These magnetic field lines form an arch over the cathode by passing directly to the central anode without reentering the uneroded sputter surface of the cathode. In a circular geometry, these arching magnetic field lines form an endless tunnel for confining a glow discharge. The tunnel thus formed is a novel and modified magnetic tunnel in which electrons are reflected electrostatically from the cathode surface near the outer edge of the cathode and reflected by magnetic mirroring near the inner edge. Use of this modified magnetic tunnel leads to improved electrical impedance characteristics of the glow discharge and to improved uniformity in cathode erosion.

Magnetically enhanced sputter source

An optimized annular sputter target for use in a sputter coating source has a cross sectional shape comprising a front surface from which material is to be sputtered, an outer rim and an inner rim, a back surface generally opposite said sputter surface, said outer rim having a first portion intersecting said back surface and a second portion intersecting said front sputter surface, said second portion extends outwardly from said first portion, said outer rim is substantially longer in a direction parallel to the axis of said annular target than is said inner rim, and said inner rim slopes outwardly from its intersection with said front sputter surface.

Sputter target for use in a sputter coating source

Magnetron sputter coating sources are usually designed for vacuum deposition of nonmagnetic materials. Such sources employ nonmagnetic sputter targets. In some cases it is desired to use the same magnetron sources to dispense magnetic materials. It is therefore desired to use magnetic sputter targets interchangeably with nonmagnetic sputter targets. The novel design approach of the present invention employs a magnetic sputter target comprising first and second magnetic target portions separated by a gap. These magnetic target portions serve as virtual pole pieces. The fringing magnetic field adjacent the gap serves to position and enhance the glow discharge. By controlling the configurations of these virtual pole pieces and the gap between them, the glow discharge and the corresponding target erosion pattern may, within limits, be shaped as desired. The magnetic target portions need not be magnetically saturated. Hence they may be made relatively thick in cross-section, thereby providing relatively large reservoirs of magnetic sputter target material.

Magnetic targets for use in sputter coating apparatus

An RF sputtering system having a rotating substrate table includes a resonant circuit adapted to rotate with the substrate table whereby reactive currents need not propagate across the rotating RF connector through which RF power is supplied to the rotating table.

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Mountain View, CA, United States of America

Lawrence T Lamont, Jr