Abrasive tool making process – material – or composition – With synthetic resin
Reexamination Certificate
2001-12-21
2003-09-16
Marcheschi, Michael (Department: 1755)
Abrasive tool making process, material, or composition
With synthetic resin
C051S307000, C051S308000, C051S309000, C106S003000, C438S692000, C438S693000
Reexamination Certificate
active
06620215
ABSTRACT:
FIELD OF THE INVENTION
The present invention comprises an abrasive composition for chemical mechanical planarization (CMP), which contains abrasive particles comprising an organic resin; methods of preparing the organic resin particles; methods of tailoring the abrasive composition for selective CMP applications; and a method of preparing a semiconductor device using the abrasive composition.
BACKGROUND OF THE INVENTION
CMP is a commonly used technology in semiconductor industry. The pure substrate surface and complex surface of semiconductor wafer, dielectric layer, conducting wire and barrier materials in the integrated circuits have to be polished to achieve a certain degree of planarity, which is extremely important to reach a high density of integrated circuits. In general, CMP technology consists of four major specific technologies including slurry, pad, polisher and post-cleaning device. The CMP slurry provides a chemical environment to wet and adjust the interaction between abrasive, pad and the wafer surface, and also moderates the mechanical force on the polishing surface. The slurry plays a key role in CMP process and determines the production efficiency and product quality.
The present invention relates generally to the preparation of semiconductor devices and more particularly to improved slurry compositions for the chemical-mechanical planarization (CMP) of metal (e.g., Cu) layers and barrier materials (e.g., Ta, TaN, etc.) and dielectric materials for their polishing.
A semiconductor wafer typically includes a substrate, such as a silicon wafer, on which a plurality of integrated circuits have been formed. In the manufacture of integrated circuits, wafer surface planarity and quality is of extreme importance. In order to achieve the degree of planarity required to produce ultra high density integrated circuits, CMP processes are being employed.
In general, CMP involves pressing a semiconductor wafer against a moving polishing surface that is wetted with a chemically reactive, abrasive slurry. Conventional slurries either are acidic or basic, and generally contain alumina, silica, zirconium oxide, magnesium oxide, or cerium oxide abrasive particles. The polishing surface usually is a planar pad made of a relatively soft, porous material, such as polyurethane. The pad usually is mounted on a planar platen. Continuous pad devises also are being tested. Systems devoid of a slurry where the pad contains the abrasive also are being used.
Integrated circuits are chemically and physically integrated into a substrate by patterning regions in the substrate and layers on the substrate. The layers generally are formed of various materials having either a conductive, insulating, or semiconducting nature. Also, barrier materials or barriers are used to prevent the migration of ions and adhesion promoters. In order for a device to have high yields, it is crucial to start with a flat semiconductor wafer. If the surface is not: uniform (e.g., areas of unequal elevation or surface imperfections), various problems can occur which may result in a large number of inoperable devices. Further details can be found in the following references: Luo, et al., “Chemical-Mechanical Polishing of Copper: A Comparative Analysis,” February 13-14 CMP-MIC Conference, 1997 ISMIC—200:197/0083; Babu, et al., “Some Fundamental and Technological Aspects of Chemical-Mechanical Polishing of Copper Films: A Brief Review,” Feb. 19-20, 1998 CMP-MIC Conference, 1998 IMIC—300P98/0385; Tseng, et al., “Effects of mechanical characteristics on the chemical-mechanical polishing of dielectric thin films,” Thin Solid Films, 290-291 (1996) 458-463; Nanz, et al., “Modeling of Chemical-Mechanical Polishing: A Review,” IEEE Transactions on Semiconductor Manufacturing, Vol. 8, No. 4, November 1995; Stiegerwald, et al., “Pattern Geometry Effects in the Chemical-Mechanical Polishing of Inlaid Copper Structures,”: “J. Electrom. Soc., Vol 141, Oct. 10, 1994; Fury, “Emerging developments in CMP for semiconductor planarization—Part 2,” Solid State Technology, 81-88, July 1995; Fury, “CMP Standards: A Frustration Cure,” Semiconductor International, November 1995.
Surface planarity is of paramount importance in microelectronics. With the integrated technology approaching the era of Ultra Large Scale Integration (ULSI), CMP is touted as the only viable technique to meet today's planarity requirements. Some of the most important issues in CMP today addressed to dishing and erosion, corrosion, defects of the surface, include the control of polishing rate and selectivity among different materials on the surface. The prior art attempts to accomplish these goals as follows.
U.S. Pat. No. 4,959,113 discloses a method of polishing metal surfaces with aqueous slurries. The slurry composition comprises water, abrasives such as SiO
2
, Al
2
O
3
, TiO
2
, ZrO
2
, CeO
2
, SnO
2
, SiC, TiC, and a salt containing any cation of group IIA, IIIA, IVA, or IVB and any anion of chloride, bromide, iodide, nitrate, sulfate phosphate, or perchlorate. The patent also discloses a pH range of 1-6 which is adjusted with mineral acids.
U.S. Pat. No. 5,084,071 discloses the CMP slurry, which comprises abrasive particles, e.g. SiO
2
, CeO
2
, Fe
2
O
3
, SiC, Si
3
N
4
, containing less than 1%(w/w) of alumina, and a transition metal chelated salt (e.g. EDTA) as a polishing accelerator.
U.S. Pat. No. 5,114,437 discloses the CMP slurry for polishing an aluminum substrate, which contains an alumina with an average particle size of 0.2-0.5&mgr;, and a polishing accelerator selected from the group consisting of chromium (III) nitrate, lanthanum nitrate, ammonium cerium (III) nitrate and neodymium nitrate.
U.S. Pat. No. 5,209,816 discloses a method for polishing Al- or Ti-containing metal layer with the CMP slurry, which contains inorganic abrasive materials, 0.1-20% by volume of H
3
PO
4
and 1-30% by volume of H
2
O
2
.
U.S. Pat. No. 5,225,034 discloses the CMP slurry for polishing copper layer on a semiconductor wafer to produce copper wire on the wafer. The slurry comprises AgNO
3
, inorganic abrasive particles and an oxidant selected from H
2
O
2
, HClO, KClO, K
2
MnO
4
, or CH
3
COOOH.
U.S. Pat. No. 5,340,370 discloses the CMP slurry for polishing tungsten or tungsten nitride film, which comprises an oxidizing agent such as potassium ferricyanide, inorganic abrasive particles, water, and has a pH of 2-4.
U.S. Pat. No. 5,366,542 discloses a CMP slurry comprising alumina abrasive particles, chelating agent selected from the group consisting of polyaminocarboxylic acid (EDTA) and sodium or potassium salts, and may further contain boehmite or an aluminum salt.
U.S. Pat. No. 5,391,258 discloses a CMP slurry for polishing silicon, silica or silicate composite. The slurry comprises, in addition to inorganic abrasive particles, hydrogen peroxide and potassium hydrogen phthalate.
U.S. Pat. No. 5,516,346 discloses a CMP slurry for titanium film. The slurry contains potassium fluoride, inorganic abrasive particles such as silica, and pH<8.
U.S. Pat. No. 5,527,423 discloses the slurry for polishing a metal layer, which comprises an oxidizing agent such as iron nitrate, alumina particles containing at least 50% gamma phase, nonionic surfactants such as polyalkyl siloxanes, or polyoxyalkylene ethers.
U.S. Pat. No. 6,171,352 discloses a CMP slurry which contains, in addition to inorganic abrasive particles, an abrasion accelerator, wherein the abrasion accelerator comprises monocarboxy group- or an amino group-containing compound and optionally a nitrate salt, also a viscosity modifier such as polyacrylic acid or its copolymer.
U.S. Pat. No. 6,258,721 discloses an innovative CMP slurry using diamond particles as an abrasive material, comprising ingredients such as an oxidizing agent, chelating agent, surfactant and others.
In summary, all reported CMP slurries employ inorganic particles as abrasive materials and as such, cannot achieve the combination of an efficient polishing rate and selectivity for removing different materials from the surface. The present inven
Bian Guomin
Chan Leina
Li Yuzhuo
Lin Yong
Tang Kwok
Birch & Stewart Kolasch & Birch, LLP
Dynea Canada Ltd.
Marcheschi Michael
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