Chemistry: electrical and wave energy – Processes and products – Coating – forming or etching by sputtering
Reexamination Certificate
1999-02-17
2001-04-17
McDonald, Rodney (Department: 1753)
Chemistry: electrical and wave energy
Processes and products
Coating, forming or etching by sputtering
C204S298060, C204S298080, C204S298120, C118S7230IR, C118S7230IR, C156S345420, C427S569000
Reexamination Certificate
active
06217718
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to methods and apparatus for sputtering ionized material from a solid target, or cathode, onto a workpiece or etching a workpiece with the aid of an inductively coupled plasma.
In the performance of a variety of semiconductor device fabrication procedures, ions are directed against a workpiece, such as a semiconductor wafer, or a group of semiconductor wafers. Such an operation involves creation of a plasma in a processing chamber, the plasma being created by establishing an RF field within the processing chamber, while the chamber contains a gas which is ionized by the field. In the case of an inductively coupled plasma generator, the field is produced by a coil.
In one process, a target body is also disposed in the chamber and is electrically biased to a potential that will attract ions to the target. Bombardment of the target with ions causes atoms of the target material to be ejected from the surface thereof. This action, known as “sputtering”, is conventionally aided by associating the target with a magnet assembly, or magnetron, which produces a magnetic field that facilitates the creation of ions in the vicinity of the target.
Atoms ejected from the target may be ionized in the plasma and the substrate may be biased to a potential that will attract the target material ions. Typically, the target material is a metal, such as titanium or aluminum. Because the ions to be attracted to the substrate are usually positively charged, the substrate is, therefore, typically negatively biased.
The coil employed to produce the inductively coupled plasma acts as the primary winding of a transformer, with the plasma acting as a single turn secondary winding of the transformer.
Sputtering apparatus typically have a shield to protect the interior walls of the chamber from the sputtered material. As set forth in greater detail in copending application Ser. No. 08/559,345, filed Nov. 15, 1995, allowed entitled “Method and Apparatus for Generating a Plasma” and assigned to the assignee of the present application, the plasma generating coil of apparatus of this type can be installed within the shield of the processing chamber or mounted outside of the chamber shield. In either form of construction, the coil can have a single turn or a plurality of turns.
When the plasma generating coil is installed within the processing chamber shield, as set forth in codending application Ser. No. 08/680,335, filed Jul. 10, 1996, now abandoned entitled “Coils for Generating a Plasma and for Sputtering” and assigned to the assignee of the present application, the coil can be made of a material which permits the coil to provide an auxiliary sputtering source. In addition, as set forth in copending application Ser. No. 08/857,921, filed May 16, 1997 allowed entitled “Use of Variable Impedance to Control Coil Sputter Distribution” and assigned to the assignee of the present application, it has been found that both the rate at which material is sputtered from such a coil and the RF voltage distribution around the coil can vary as a function of coil location about the center axis of the processing chamber. These variances can contribute to nonuniformities in the processing of workpieces.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to reduce the effects of the above-described variations.
A more specific object of the invention is to position the plasma generating coil within the processing chamber in such a manner as to prevent or minimize variations, about the center axis of the processing chamber, in the quantity of ions delivered to the workpiece.
These and other objects and advantages are achieved in a semiconductor processing chamber which, in accordance with one aspect of the present invention, has a sputtering coil which is angled with respect to the central axis of the chamber or the plane of the upper surface of the workpiece. Such an arrangement is believed to compensate for nonuniform RF voltage distributions around the circumference of the coil. As a result, it is believed that variations in plasma density and coil sputtering rate as a function of coil circumference position may be reduced.
In an another aspect of the present invention, the interior area of the coil which can provides a primary sputtering surface of the coil may be varied in size as a function of coil circumference location. As a consequence, it is believed that the quantity of material sputtered from the coil onto the workpiece may be made more uniform with respect to angular location of the coil.
REFERENCES:
patent: 4123316 (1978-10-01), Tsuchimoto
patent: 4336118 (1982-06-01), Patten et al.
patent: 4422896 (1983-12-01), Class et al.
patent: 4626312 (1986-12-01), Tracy
patent: 4661228 (1987-04-01), Mintz
patent: 4842703 (1989-06-01), Class et al.
patent: 4844775 (1989-07-01), Keeble
patent: 4871421 (1989-10-01), Ogle et al.
patent: 4918031 (1990-04-01), Flamm et al.
patent: 4925542 (1990-05-01), Kidd
patent: 4941915 (1990-07-01), Matsuoka et al.
patent: 4948458 (1990-08-01), Ogle
patent: 4990229 (1991-02-01), Campbell et al.
patent: 4999096 (1991-03-01), Nihei et al.
patent: 5102496 (1992-04-01), Savas
patent: 5122251 (1992-06-01), Campbell et al.
patent: 5135634 (1992-08-01), Clarke
patent: 5146137 (1992-09-01), Gesche et al.
patent: 5178739 (1993-01-01), Barnes et al.
patent: 5198725 (1993-03-01), Chen et al.
patent: 5231334 (1993-07-01), Paranjpe
patent: 5234560 (1993-08-01), Kadlec et al.
patent: 5241245 (1993-08-01), Barnes et al.
patent: 5304279 (1994-04-01), Coultas et al.
patent: 5346578 (1994-09-01), Benzing et al.
patent: 5361016 (1994-11-01), Ohkawa et al.
patent: 5397962 (1995-03-01), Moslehi
patent: 5401350 (1995-03-01), Patrick et al.
patent: 5404079 (1995-04-01), Ohkuni et al.
patent: 5418431 (1995-05-01), Williamson et al.
patent: 5429070 (1995-07-01), Campbell et al.
patent: 5429995 (1995-07-01), Nishiyama et al.
patent: 5430355 (1995-07-01), Paranjpe
patent: 5433812 (1995-07-01), Cuomo et al.
patent: 5464476 (1995-11-01), Gibb et al.
patent: 5503676 (1996-04-01), Shufflebotham et al.
patent: 5525159 (1996-06-01), Hama et al.
patent: 5573595 (1996-11-01), Dible
patent: 5639357 (1997-06-01), Xu
patent: 5650032 (1997-07-01), Keller et al.
patent: 5683537 (1997-11-01), Ishii
patent: 5690781 (1997-11-01), Yoshida et al.
patent: 5707498 (1998-01-01), Ngan
patent: 5763851 (1998-06-01), Forster et al.
patent: 5795428 (1998-08-01), Ishii et al.
patent: 5810931 (1998-09-01), Stevens et al.
patent: 5851600 (1998-12-01), Horiike et al.
patent: 5874704 (1999-02-01), Gates
patent: 0520519 (1992-06-01), None
patent: 0607797 (1994-01-01), None
patent: 2162365 (1986-01-01), None
patent: 2231197 (1990-11-01), None
patent: 59-190363 (1984-10-01), None
patent: 61-190070 (1986-08-01), None
patent: 6232055 (1994-08-01), None
patent: 6283470 (1994-10-01), None
patent: 7176399 (1995-07-01), None
patent: 7176398 (1995-07-01), None
patent: 8153712 (1996-06-01), None
patent: 8288259 (1996-11-01), None
patent: 8606923 (1986-11-01), None
Hayden, D.B., et al., “Characterization of magnetron-sputtered partially ionized aluminum deposition,” J. Vac. Sci. Technol. A 16(2), 624-627.
Schneider, Jochen M., et al., “Crystalline alumina deposited at low temperature by ionized magnetron sputtering,” J. Vac. Sci. Technol. A15(3), pp. 1084-1088.
N. Jiwari et al., “Helicon wave plasma reactor employing single-loop antenna,”J. of Vac. Sci. Technol., A 12(4), pp. 1322-1327, Jul./Aug. 1994.
S.M. Rossnagel et al., “Magnetron Sputter Deposition with High Levels of Metal Ionization,”Appl. Phys. Lett., vol. 63, pp. 3285-3287, 1993.
J. Hopwood et al., “Mechanisms for Highly Ionized Magnetron Sputtering,”J. Appl. Phys., vol. 78, pp. 758-765, 1995.
S.M. Rossnagel, “Directional and Ionized Sputter Deposition for Microelectronics Applications,”Proc. of 3rd ISSP(Tokyo), pp. 253-260, 1995.
M. Yamashita, “Fundamental Characteristics of Built-in High Frequency Coil Type Sputtering Apparatus,”J. Vac. Sci. Technol., vol. A7, pp. 151-158, 1989.
M. Yamashita, “Sputter Type High Frequency
Holmann Ralf
Xu Zheng
Applied Materials Inc.
Konrad Raynes & Victor
McDonald Rodney
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