Abrading – Abrading process – Utilizing fluent abradant
Reexamination Certificate
1999-02-26
2002-04-23
Morgan, Eileen P. (Department: 3723)
Abrading
Abrading process
Utilizing fluent abradant
C451S041000, C451S054000, C451S060000, C451S063000
Reexamination Certificate
active
06375544
ABSTRACT:
TECHNICAL FIELD
The present invention concerns methods of making integrated circuits, particularly methods of polishing or planarizing surfaces.
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 build the circuits layer by layer, using techniques, such as doping, masking, and etching, to form 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.
One important concern during fabrication is flatness, or planarity, of various layers of the integrated circuit. For example, planarity significantly affects the accuracy of a photo-imaging process, known as photomasking or photolithography, which entails focusing light on light-sensitive materials to define specific patterns or structures in a layer of an integrated circuit. In this process, the presence of hills and valleys in a layer means that various regions of the layer will be in or out of focus and that certain resulting structural features in the layer will be smaller or larger than intended. Moreover, hills and valleys can reflect light undesirably onto other regions of a layer and add undesirable features, such as notches, to desired features. These problems can be largely avoided if the layer is sufficiently planar.
One process for making surfaces flat or planar is known as chemical-mechanical planarization or polishing. Chemical-mechanical planarization, often called CMP for short, typically entails applying a fluid containing abrasive particles to a surface of an integrated circuit, and polishing the surface with a rotating polishing head. (In some instances, both the surface and the polishing head rotate.) The mixture of the fluid and abrasive particles is known as a slurry. The polishing head typically includes several holes, known as slurry dispensers, which dispense the slurry onto the surface during polishing. After polishing, a gas, such as air or nitrogen, is forced through the slurry dispensers to facilitate separation of the polished surface from the polishing head.
One problem that the inventor recognized with this planarization method is that forcing air or nitrogen through slurry dispensers immediately after polishing occasionally dries slurry on the polished surface, causing particles in the slurry to stick to the polished surface. Although the polished surface is sometimes rinsed following the polishing process, some of the particles remain on the polished surface as defects. Accordingly, there is a need for a chemical-mechanical planarization technique that reduces the chance of these defects.
SUMMARY OF THE INVENTION
To address these and other needs, the inventor devised a new method of polishing or planarization with the potential for reducing the chance of slurry particles (or particulates) adhering to polished surfaces and thus the chance of leaving defects on the polished surfaces. In particular, one embodiment of the method dispenses slurry through one or more slurry dispensers in the polishing head onto the surface, polishes the surface, and then dispenses a substantially particulate-free liquid through one or more of the slurry dispensers. Unlike gases, such as air and nitrogen, the substantially particulate-free liquid facilitates separation of the polishing head and the surface, without drying slurry on the surface. In an exemplary embodiment, the polishing head is part of a chemical-mechanical polishing machine, and the substantially-particulate-free liquid is deionized water.
REFERENCES:
patent: 5227001 (1993-07-01), Tamaki et al.
patent: RE34425 (1993-11-01), Schultz
patent: 5486129 (1996-01-01), Sandhu et al.
patent: 5514245 (1996-05-01), Doan et al.
patent: 5563709 (1996-10-01), Poultney
patent: 5643060 (1997-07-01), Sandhu et al.
patent: 5643061 (1997-07-01), Jackson et al.
patent: 5658183 (1997-08-01), Sandhu et al.
patent: 5664990 (1997-09-01), Adams et al.
patent: 5679169 (1997-10-01), Gonzales et al.
patent: 5700180 (1997-12-01), Sandhu et al.
patent: 5702292 (1997-12-01), Brunelli et al.
patent: 5730642 (1998-03-01), Sandhu et al.
patent: 5738567 (1998-04-01), Manzonie et al.
patent: 5762537 (1998-06-01), Sandhu et al.
patent: 5816900 (1998-10-01), Nagahara et al.
patent: 5842909 (1998-12-01), Sandhu et al.
patent: 5851135 (1998-12-01), Sandhu et al.
patent: 5894852 (1999-04-01), Gonzales et al.
patent: 5895550 (1999-04-01), Andreas
“The World's Most Popular, Fully Automated CMP Tool”,IPEC Planar, CMP Equipment, Avanti 472 at http://207.108.158.32/planar/472.html, 1-4, (Feb. 8,1999).
Blatt, C., et al., “Integrated CMP and Post-CMP Cleaning Cluster Particle Removal with DI Water”,IPEC Planar, Process Paper at http://www.ipec.com/planar/paper2.html, 1-6, (Jul. 9, 1998).
Holland, K., et al., “Planarization by CMP for ULSI Applications”,IPEC Planar, Process Technology, Process Paper at http://www.ipec.com/planar/paper1.html, 1-6, (Jul. 9, 1998).
IPEC, “Introducing the AvantGaard 676”,IPEC Planar, CMP Equipment AvantGaard 676 at http://207.108.158.32/planar/676.html, 1-8, (Feb. 8, 1999).
IPEC, “Introducing the AvantGaard 776, The World's Most Advanced CMP Technology”,IPEC Planar, CMP Equipment, AvantGaard 776 at http://207.108.158.32/planar/776.html, 1-13, (Feb. 8, 1999).
Parikh, P.J., “Chemical Mechanical Planarization: An Analysis of Variables”,IPEC Planar, http://www.ipec.com/planar/paper3.html, 1-9, (Jul. 9, 1998).
Morgan Eileen P.
Schwegman Lundberg Woessner & Kluth P.A.
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