Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
1999-08-02
2003-01-21
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
Composite
Of silicon containing
C428S457000, C428S660000
Reexamination Certificate
active
06509102
ABSTRACT:
BACKGROUND OF THE INVENTION
As computer chips become “faster” and more capable, there is a corresponding increased demand for improved materials and methods of manufacturing. Although computer chips, i.e. semi-conductor devices, are manufactured by many techniques, a typical important step in the manufacture is the deposition of thin films on a substrate. The present invention focuses on physical vapor deposition, PVD, wherein a mass of metal, i.e. “a target”, is shaped such that when a plasma is excited in a rarefied atmosphere, such as argon, at a very low pressure, the high speed atoms of argon dislodge metal atoms from the target. Atoms from the target thus freed, deposit a thin film on a substrate or wafer, e.g. a single crystal of silicon, located near the target. Following a number of various operations and additional film depositions, the wafer is made ready for dicing into individual chips. A few to several dozen chips may be obtained from an individual wafer. The resulting chips provide various functions in a typical computer, for example, memory, logic and application specific tasks, etc.
Articles embodying the chips are often made by designs that include trenches, contact holes and via holes (also referred to as “vias”) in very small diameters. It is important that the film coverage of the bottom of the contact holes, vias, and trenches, referred to as “step coverage”, be maintained to a useful degree so that smaller diameters of such holes can be used as higher aspect ratios are desired in applications where electrical connection between layers is required. The present invention provides a titanium sputtering target which enables improved step coverage.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided a titanium sputtering target that has particular texture with high fractions of <
20
-
23
> and <
11
-
20
> orientations perpendicular to target plane. The texture may be defined by intensities for various crystal planes that are parallel to the target plane. A value of intensity for a crystal plane in a textured target is expressed as multiples of the intensity for the same crystal planes in a Ti sample with a random grain orientation distribution. Intensities of crystal planes are obtained from orientation distribution function based on four measured pole figures from X-ray diffraction.
In addition, the invention concerns a method of providing a titanium sputtering target with particular desired orientation and texture, and titanium sputtering targets that are especially useful in physical vapor deposition processes to improve step coverage.
REFERENCES:
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patent: 5798005 (1998-08-01), Murata et al.
patent: 5952086 (1999-09-01), Ohnishi et al.
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patent: 8-269701 (1996-10-01), None
patent: 9-25565 (1997-01-01), None
patent: WO9628583 (1996-03-01), None
patent: PCT/US98/12734 (1998-06-01), None
Honeywell International , Inc.
Jones Deborah
McNeil Jennifer
Wells St. John P.S.
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