Semiconductor device manufacturing: process – Chemical etching – Vapor phase etching
Reexamination Certificate
2001-10-26
2003-06-10
Cuneo, Kamand (Department: 2829)
Semiconductor device manufacturing: process
Chemical etching
Vapor phase etching
C438S618000, C438S648000, C438S649000, C438S656000, C438S689000, C438S694000, C438S695000, C438S720000, C438S734000, C438S745000, C438S754000, C438S785000, C156S922000, C156S922000, C156S922000
Reexamination Certificate
active
06576563
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention is directed, in general, to semiconductor devices and, more specifically, to a method of manufacturing a semiconductor device employing a fluorine-based etch substantially free of hydrogen.
BACKGROUND OF THE INVENTION
The semiconductor manufacturing industry is continually striving to manufacture smaller, faster and more reliable semiconductor devices. To this end, both active and passive devices are continually improved to enhance overall integrated circuit (IC) performance. As is well known, various active devices and other structures are commonly formed within an IC. These various active devices and structures are what allow fast, reliable and inexpensive ICs to be manufactured for today's ever competitive computer and telecommunications markets.
The fabrication of semiconductor devices, such as contacts and capacitors, typically involves numerous distinct steps. Among the final steps is a metallization stage where metal patterns in such contacts are photolithographically defined. Once defined, these patterns are etched to disassociate the contacts (or other device being manufactured) from other areas or devices during a post-metal etch process.
In conventional processes, the post-metal etch consists of a series of repeated steps employed to remove photoresist present around the contacts or other devices, as well as to purge harmful chemicals, such as chlorine (Cl
2
), from the layers. It is well known that traces of chlorine left behind may result in a catalytic reaction with water present in the process and may result in the creation of aluminum hydroxide (AlOH) in those devices formed with aluminum. Oxygen (O
2
) or fluorine (F
2
) is commonly used to purge the chlorine from the sidewalls of devices in alternating steps of strip and passivation-strip-passivation during the post-metal etch process.
Unfortunately, conventional etch techniques often leave conductive material that provide electrical connections between portions of the contact or device and other portions of an integrated circuit (IC). In those layers forming the contact or device, typically a metal layer of titanium nitride (TiN) not etched completely through, remaining electrical connections often result in short-circuits across such under-etched portions. These short-circuits are typically found in the lower layers of contacts or devices where defects in upper layers have blocked the etch of the lower layers. Those layers having short-circuits, often referred to “stringers,” after the post-metal etch often result in undesirable current across portions of the device, which substantially reduces product yields. This result is, of course high undesirable in view of the economics of IC fabrication that demand maximum device yields, especially at the “back-end” (or latter stages) of the manufacturing process where the device wafers are most valuable.
Accordingly, what is needed in the art is an improved method of manufacturing semiconductor devices, as well as integrated circuits, that does not suffer from such deficiencies found in the prior art.
SUMMARY OF THE INVENTION
To address the above-discussed deficiencies of the prior art, the present invention provides a method of manufacturing a semiconductor device. In one embodiment, the method includes forming a positive relief structure from a material located on a substrate, the step of forming the positive relief structure leaving an unwanted remnant of said material proximate a base of the positive relief structure. The method further includes cleaning the positive relief structure. In addition, the method includes removing the unwanted remnant with a gas containing fluorine and that is substantially free of hydrogen. In another aspect, the present invention provides a method of manufacturing an integrated circuit using this method.
The foregoing has outlined preferred and alternative features of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention.
REFERENCES:
patent: 4877482 (1989-10-01), Knapp et al.
patent: 5420071 (1995-05-01), Burke
Graff et al. (“Wafer Cleaning/Stripping rf and microwave plasma for resist and post-etch polymer removal”, Solid State Technology, Dec. 2001, pp. 37-38, 40, 42).
Downey Stephen W.
Harris Edward B.
Murphey Paul B.
Agere Systems Inc.
Kilday Lisa
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