Abrasive tool making process – material – or composition – With inorganic material
Reexamination Certificate
2000-09-29
2002-05-07
Marcheschi, Michael (Department: 1755)
Abrasive tool making process, material, or composition
With inorganic material
C051S308000, C051S309000, C106S003000, C106S008000, C438S692000, C438S693000
Reexamination Certificate
active
06383240
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an aqueous dispersion for chemical mechanical polishing. More specifically, the invention relates to an aqueous dispersion that is particularly useful for chemical mechanical polishing of working films of semiconductor devices and the like. The aqueous dispersion for chemical mechanical polishing of the invention has low generation of coarse solids during storage or transport, has less fear of causing scratches and the like, and maintains excellent polishing performance even after storage and transport.
2. Description of the Prior Art
With improved integration and multilayer wiring of semiconductor devices, the technique of chemical mechanical polishing (hereunder referred to as “CMP”) is being introduced for polishing of working films and the like. This is a process whereby a wiring material such as tungsten, aluminum, copper or the like is embedded in a hole or groove formed in an insulating film on a processing wafer and then polishing is performed to remove the excess wiring material to thereby form the wiring. For such polishing, the abrasive particles used are usually inorganic particles of alumina, silica, zirconia or the like, or organic particles of polystyrene, polymethyl methacrylate or the like. Aqueous dispersions containing these abrasive particles can accomplish polishing of working films at sufficient rates.
Resinous or metallic sealed containers are commonly used for storage or transport of aqueous dispersions for CMP, but increasing temperature during storage can cause evaporation of moisture at the gas-liquid interface, which upon drying results in production of solids made of the abrasive particles. During transport, vibrations on the container can result in adhesion of the aqueous dispersion to the inner wall surface, with evaporation of moisture from the adhered aqueous dispersion leading to production of dried solids. These solids become included in the aqueous dispersion as coarse particles, and during polishing these coarse particles can cause scratching of polishing surfaces. They can also lead to clogging of conduits used for supply of the aqueous dispersion.
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
It is an object of the present invention to overcome the problems of the prior art described above, by providing an aqueous dispersion for CMP that has low generation of coarse particles from abrasive particles or the like during storage and transport, and maintains excellent polishing performance . In particular, it is an object to provide an aqueous dispersion for CMP that allows polishing of working films and the like of semiconductor devices at a sufficient rate and produces no scratches, even after storage and transport.
Features of the Invention
The aqueous dispersion for CMP according to the first aspect of the invention is characterized by comprising abrasive particles, an amphipathic compound and water.
The aqueous dispersion for CMP according to the second aspect of the invention is characterized by comprising abrasive particles and water, wherein a boundary film is formed at the interface between the aqueous dispersion and the air.
The boundary film according to the second aspect of the invention is composed of an amphipathic compound to inhibit escape of moisture, as according to the third aspect of the invention. That is, the aqueous dispersion for CMP according to the third aspect is characterized in that the boundary film of the second aspect of the invention is composed of an amphipathic compound. According to the second and third aspects of the invention, the “boundary film” formed at the interface between the aqueous dispersion and the air inhibits production of solids due to escape of moisture from the gas-liquid interface during storage or from the aqueous dispersion adhering to the upper inner wall surface due to vibrations on the container during transport.
The fourth aspect of the invention specifies the preferred range for the HLB value which represents the hydrophilic/lipophilic balance of the amphipathic compound, and it is characterized in that the HLB value is greater than 0 but no greater than 6.
Effect of the Invention
According to the first to third aspects of the invention, there is provided an aqueous dispersion for CMP that has low generation of coarse solids from abrasive particles and the like, maintains adequate polishing rate even after storage and transport, and produces no scratching. The aqueous dispersion is particularly useful for CMP of working films on semiconductor devices. Furthermore, by using specific amphipathic compounds as according to the fourth aspect, it is possible to produce aqueous dispersions for CMP that maintain even more stable polishing performance.
DETAILED DESCRIPTION OF THE INVENTION
The “abrasive particles” are not particularly restricted, and either inorganic particles or organic particles, or organic/inorganic composite particles, may be used.
As inorganic particles there may be mentioned silica, alumina, ceria, zirconia, titania and the like. For high purity, the inorganic particles are most preferably synthesized by a fumed process (high-temperature flame hydrolysis), a gas phase process by Nanophase Technology Corp. (metal vapor deposition oxidation) or a sol-gel process whereby synthesis is accomplished by hydrolyzing condensation from a metal alkoxide.
As organic particles there may be used polymer particles composed of a thermoplastic resin made of polystyrene and a styrene-based copolymer, or a (meth)acrylate resin such as polymethyl methacrylate and an acryl-based copolymer. There may also be used polymer particles composed of thermosetting resins such as phenol resin, urea resin, melamine resin, epoxy resin, alkyd resin or unsaturated polyester resin.
Polymer particles composed of a thermoplastic resin and polymer particles composed of a thermosetting resin may also be used in combination.
As organic/inorganic composite particles there may be mentioned composite particles which are organic particles evenly coated with inorganic particles, composite particles wherein a polymer is adhered or bonded to inorganic particles, or composite particles wherein a polymer film is formed on the surface of inorganic particles. Inorganic particles, organic particles and organic/inorganic composite particles may also be used in combination of two or more.
The content of the abrasive particles may be 0.05-20 parts by weight (hereunder referred to as “parts”), especially 0.07-15 parts and more preferably 0.1-10 parts, with respect to 100 parts of the aqueous dispersion, in terms of the total of the inorganic particles, organic particles and organic/inorganic composite particles. If the abrasive particle content is less than 0.05 part it may not be possible to achieve an aqueous dispersion with sufficient polishing performance. A content of greater than 20 parts is also not preferred as the cost is increased and the stability of the aqueous dispersion may be reduced.
The “amphipathic compound” is a compound having both a hydrophilic portion and a lipophilic portion in the molecule. The hydrophilic portion may be a hydroxyl group, ester group, carboxyl group or the like, and the lipophilic portion may be a relatively long-chained hydrocarbon group. As such compounds there may be mentioned (1) aliphatic alcohols, (2) fatty acids, (3) sorbitan fatty acid esters, (4) glycerin fatty acid esters, (5) propylene glycol fatty acid esters and (6) esters of polyethyleneglycol and fatty acids. The hydrocarbon groups of these compounds may have unsaturated bonds, and they may be linear or branched.
The following compounds may be mentioned as specific amphipathic compounds of the types listed above.
(1) Aliphatic alcohols: Monoalcohols of 6-18 carbons and polyols such as diols of 12-18 carbons and triols of 12-18 carbons are suitable for use. As specific examples there may be mentioned hexanol (HLB value: approx. 6), heptanol, octanol, decanol, dodecanol, tetradecanol (HLB value: approx. 1), hexadecano
Kawahashi Nobuo
Kikuchi Osamu
Nishimoto Kazuo
JSR Corporation
Marcheschi Michael
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
LandOfFree
Aqueous dispersion for chemical mechanical polishing does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Aqueous dispersion for chemical mechanical polishing, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Aqueous dispersion for chemical mechanical polishing will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2878181