Active solid-state devices (e.g. – transistors – solid-state diode – With means to control surface effects – Insulating coating
Reexamination Certificate
2001-09-04
2003-09-02
Fahmy, Wael (Department: 2813)
Active solid-state devices (e.g., transistors, solid-state diode
With means to control surface effects
Insulating coating
C257S762000
Reexamination Certificate
active
06614099
ABSTRACT:
FIELD OF THE INVENTION
The present invention concerns methods of fabricating integrated circuits, particularly methods of forming interconnects from copper and other metals.
BACKGROUND OF THE INVENTION
Integrated circuits, the key components in thousands of electronic and computer products, are interconnected networks of electrical components fabricated on a common foundation, or substrate. Fabricators typically use various techniques, such as layering, doping, masking, and etching, to build thousands and even millions of microscopic resistors, transistors, and other electrical components on a silicon substrate, known as a wafer. The components are then wired, or interconnected, together to define a specific electric circuit, such as a computer memory.
Interconnecting millions of microscopic components typically entails covering the components with an insulative layer of silicon dioxide, etching small holes in the insulative layer to expose portions of the components underneath, and digging trenches in the layer to define a wiring pattern. Then, through metallization, the holes and trenches are filled typically with aluminum, to form line-like aluminum wires between the components. The aluminum wires are typically about one micron thick, or about 100 times thinner than a human hair.
Silicon dioxide and aluminum are the most common insulative and conductive materials used to form interconnections today. However, at sub-micron dimensions, that is, dimensions appreciable less than one micron, aluminum and silicon-dioxide interconnection systems present higher electrical resistances and capacitances which waste power and slow down integrated circuits. Moreover, at these smaller dimensions, aluminum exhibits poor electromigration resistance, a phenomenon which promotes disintegration of the aluminum wires at certain current levels. This ultimately undermines reliability, not only because disintegrating wires eventually break electrical connections but also because aluminum diffuses through surrounding silcon-dioxide insulation to form short circuits with neighboring wires. Thus, at submicon dimensions, aluminum and silicon-dioxide interconnection systems waste power, slow down integrated circuits, and compromise reliability.
Copper appears, because of its lower electrical resistivity and higher electromigration resistance to be a promising substitute for aluminum. And, many polymers, for example, fluorinated polyimides, because of their lower dielectric constants, appear to be promising substitutes for silicon dioxide. Thus, a marriage of copper with these polymers promises to yield low-resistance, low-capacitance interconnective structures that will improve the efficiency and speed of integrated circuits.
Unfortunately, copper reacts with these polymers to form conductive copper dioxide within these polymers, reducing their effectiveness as low-capacitance insulators and ultimately leaving the copper-polymer promise of superior efficiency and speed unfulfilled.
SUMMARY OF THE INVENTION
To address these and other needs, the inventor has developed methods of making copper-polymer interconnection systems with reduced copper oxide. Specifically, one method uses a non-acid-based polymeric precursor, such as ester, instead of the typical acid precursor, to form a polymeric layer, and then cures the layer in a reducing or non-oxidizing atmosphere, thereby making the layer resistant to oxidation. Afterward, a zirconium, hafnium, or titanium layer is formed on the polymeric layer to promote adhesion with a subsequent copper layer. With the reduced formation of copper oxide, the method yields faster and more efficient copper-polymer interconnects.
Moreover, reducing copper-dioxidation facilitates micron and sub-micron spacing of polymer-insulated copper conductors, which would otherwise require spacings of 10 or more microns. Accordingly, another aspect of the invention is an integrated circuit including at least two conductors which are separated by no more than about one micron of a polymeric insulator. Thus, the inventor provides a method that not only yields copper-polymer interconnects of superior speed and efficiency, but also yields integrated circuits with unprecedented spacing of copper-polymer interconnects.
REFERENCES:
patent: 2842438 (1958-07-01), Saarivirta et al.
patent: 3954570 (1976-05-01), Shirk et al.
patent: 4386116 (1983-05-01), Nair et al.
patent: 4423547 (1984-01-01), Farrar et al.
patent: 4565157 (1986-01-01), Brors et al.
patent: 4574095 (1986-03-01), Baum et al.
patent: 4762728 (1988-08-01), Keyser et al.
patent: 4788082 (1988-11-01), Schmitt
patent: 4847111 (1989-07-01), Chow et al.
patent: 4931410 (1990-06-01), Tokunaga et al.
patent: 4948459 (1990-08-01), Van Laarhoven et al.
patent: 4962058 (1990-10-01), Cronin et al.
patent: 4996584 (1991-02-01), Young et al.
patent: 5019531 (1991-05-01), Awaya et al.
patent: 5034799 (1991-07-01), Tomita et al.
patent: 5084412 (1992-01-01), Nakasaki
patent: 5100499 (1992-03-01), Douglas
patent: 5130274 (1992-07-01), Harper et al.
patent: 5149615 (1992-09-01), Chakravorty et al.
patent: 5158986 (1992-10-01), Cha et al.
patent: 5173442 (1992-12-01), Carey
patent: 5231056 (1993-07-01), Sandhu
patent: 5240878 (1993-08-01), Fitzsimmons et al.
patent: 5243222 (1993-09-01), Harper et al.
patent: 5256205 (1993-10-01), Schmitt, III et al.
patent: 5334356 (1994-08-01), Baldwin et al.
patent: 5354712 (1994-10-01), Ho et al.
patent: 5413687 (1995-05-01), Barton et al.
patent: 5426330 (1995-06-01), Joshi et al.
patent: 5442237 (1995-08-01), Hughes et al.
patent: 5447887 (1995-09-01), Filipiak et al.
patent: 5470789 (1995-11-01), Misawa
patent: 5470801 (1995-11-01), Kapoor et al.
patent: 5476817 (1995-12-01), Numata
patent: 5506449 (1996-04-01), Nakano et al.
patent: 5529956 (1996-06-01), Morishita
patent: 5538922 (1996-07-01), Cooper et al.
patent: 5539060 (1996-07-01), Tsunogae et al.
patent: 5595937 (1997-01-01), Mikagi
patent: 5609721 (1997-03-01), Tsukune et al.
patent: 5625232 (1997-04-01), Numata et al.
patent: 5635253 (1997-06-01), Canaperi et al.
patent: 5654245 (1997-08-01), Allen
patent: 5662788 (1997-09-01), Sandhu et al.
patent: 5670420 (1997-09-01), Choi
patent: 5674787 (1997-10-01), Zhao et al.
patent: 5675187 (1997-10-01), Numata et al.
patent: 5679608 (1997-10-01), Cheung et al.
patent: 5681441 (1997-10-01), Svendsen et al.
patent: 5695810 (1997-12-01), Dubin et al.
patent: 5719089 (1998-02-01), Cherng et al.
patent: 5731042 (1998-03-01), Glende et al.
patent: 5739579 (1998-04-01), Chiang et al.
patent: 5763953 (1998-06-01), Iljima et al.
patent: 5780358 (1998-07-01), Zhou
patent: 5785570 (1998-07-01), Bruni
patent: 5792522 (1998-08-01), Jin et al.
patent: 5801098 (1998-09-01), Fiordalice et al.
patent: 5824599 (1998-10-01), Schacham-Diamand et al.
patent: 5891797 (1999-04-01), Farrar
patent: 5891804 (1999-04-01), Havemann et al.
patent: 5893752 (1999-04-01), Zhang et al.
patent: 5895740 (1999-04-01), Chien et al.
patent: 5897370 (1999-04-01), Joshi et al.
patent: 5907772 (1999-05-01), Iwasaki
patent: 5911113 (1999-06-01), Yao et al.
patent: 5913147 (1999-06-01), Dubin et al.
patent: 5932928 (1999-08-01), Clampitt
patent: 5933758 (1999-08-01), Jain
patent: 5948467 (1999-09-01), Nguyen et al.
patent: 5962923 (1999-10-01), Xu et al.
patent: 5968333 (1999-10-01), Nogami et al.
patent: 5969422 (1999-10-01), Ting et al.
patent: 5972179 (1999-10-01), Chittipeddi et al.
patent: 5972804 (1999-10-01), Tobin et al.
patent: 5976710 (1999-11-01), Sachdev et al.
patent: 5981350 (1999-11-01), Geusic et al.
patent: 5985759 (1999-11-01), Kim et al.
patent: 5989623 (1999-11-01), Chen et al.
patent: 5994777 (1999-11-01), Farrar
patent: 6008117 (1999-12-01), Hong et al.
patent: 6015465 (2000-01-01), Kholodenko et al.
patent: 6017820 (2000-01-01), Ting et al.
patent: 6030877 (2000-02-01), Lee et al.
patent: 6054172 (2000-04-01), Robinson et al.
patent: 6065424 (2000-05-01), Shacham-Diamond et al.
patent: 6069068 (2000-05-01), Rathore et al.
patent: 6071810 (2000-06-01), Wada et al.
patent: 6091136 (2000-07-01), Jiang et al.
patent: 6136095 (
Blum David S
Fahmy Wael
Micro)n Technology, Inc.
Schwegman Lundberg Woessner & Kluth P.A.
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