Abrading – Abrading process – Utilizing fluent abradant
Reexamination Certificate
2000-01-18
2002-04-23
Eley, Timothy V. (Department: 3723)
Abrading
Abrading process
Utilizing fluent abradant
C451S041000
Reexamination Certificate
active
06375545
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to an aqueous dispersion with excellent moisture resistance, insulation properties, antistatic properties, heat resistance, color fastness and the like, which contains polymer particles with suitable hardness and strength and which has a specific limited surfactant content. Another invention further relates to an aqueous dispersion composition for chemical mechanical polishing used for wafer polishing (hereunder referred to as “dispersion composition” or “CMP slurry”) that contains specific polymer particles, or to a CMP slurry that has a specific limited surfactant content, to particularly a CMP slurry for chemical mechanical polishing used for wafer polishing.
Further, another invention relates to an aqueous dispersion containing polymer particles with a specified mean particle size. Further another invention relates to a CMP slurry with above-mentioned aqueous dispersion, to particularly a CMP slurry which is useful for chemical machine polishing of working films. Further another invention relates to a polishing process comprising a step of polishing a wafer working film with above-mentioned specific CMP slurry. And another invention relates to a process for manufacture of a semiconductor device using the CMP slurry.
2. Prior Art
Aqueous dispersions containing fine polymer particles are used, or are being studied for use, as electronic materials, polishing materials, coating materials, paints, optical materials, catalysts, photocatalysts, electronic material film lubricants, diagnostic agents, drugs, cosmetics, conductive materials, inks, CMP slurries and the like. However, conventional aqueous dispersions have presented the following problems when applied for these purposes.
(a) Because they contain impurities such as surfactants, they can result in quality reduction when applied for these purposes.
(b) Because the antistatic properties, heat resistance, color fastness, and the like of the polymer particles are not always adequate, their use is limited depending on the purpose.
(c) Their uses are also limited because the hardness of the polymer particles is low and their strength is insufficient.
While the use of aqueous dispersions containing inorganic particles has also been studied, inorganic particles present problems because their hardness is too hard and particles with uniform shapes are difficult to obtain.
The higher integration of LSIs in recent years has led to the development of a variety of different fine working techniques. For example, the minimum working dimensions for patterns are becoming smaller year by year, and at the current time they have already reached the submicron level. A variety of techniques such as chemical mechanical polishing (hereunder, “CMP”) have also been developed to meet the stringent demands of such fine working. CMP is an essential technique for planarizing of working film surfaces such as interlayer insulation films, formation of plugs, formation of molded-in metal wiring, separation of molded-in elements, and the like.
Aqueous dispersions containing abrasive particles made of metal oxides have conventionally been used as polishing materials in CMP. However, these abrasive particles have high hardness and have therefore presented the problem of creating scratches on polishing wafer surfaces. These scratches generated during the CMP process are not desirable because they lower the reliability of the LSI.
Improvements in wafer integration, increased multilayer wirings, and the like have led to the introduction of CMP techniques for polishing of working films and the like. As disclosed in Japanese Laid-Open Patent Publication Nos. shou-62-102543, shou-64-55845 and hei-5-275366, Japanese Patent Public Inspection No. hei-8-510437, Japanese Laid-Open Patent Publication Nos. hei-8-17831, hei-8-197414, and hei-10-44047 and elsewhere, there is known a type of 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.
In this CMP process, aqueous dispersions containing metal oxide abrasive particles have traditionally been used as polishing materials. However, these abrasive particles have high hardness and have, therefore, presented the problem of creating nicks on polishing wafer surfaces. These nicks generated during the CMP process are not desirable because they lower the reliability of the LSI. In order to prevent such nicks, Japanese Laid-Open Patent Publication No. 9-285957 has proposed a polishing material having abrasive particles made of colloidal silica or the like, with the inclusion of scratch-preventing particles made of polyurethane resin or the like, having a larger size than the abrasive particles. However, when polishing materials containing such large-sized, low hardness scratch-preventing particles are used, this has presented the problem of a vastly reduced polishing rate compared to polishing materials containing abrasive particles made of metal oxides.
Japanese Laid-Open Patent Publication No. 7-86216 describes a polishing material (particularly CMP slurry) containing abrasive particles composed mainly of an organic polymer compound or the like instead of abrasive particles made of a metal oxide. It is explained that using the polishing material for polishing of wafer working films can prevent generation of nicks in the polishing wafer surface. However, abrasive particles made of this organic polymer compound have low hardness, and polishing materials composed mainly of these abrasive particles also give vastly lower polishing rates compared to polishing materials containing abrasive particles made of metal oxides.
Thus, the inventions described in these patent publications cannot achieve highly reliable high-speed polishing of working films for manufacture of semiconductor device (including various devices (wafers, device comprising wafer and the like)), nor do they allow efficient manufacture of wafers.
PROBLEMS TO BE SOLVED BY THE INVENTION
It is an object of the present invention to provide an aqueous dispersion and a CMP slurry with excellent moisture resistance, insulation properties, antistatic properties, heat resistance, color fastness and the like, which contains polymer particles with suitable hardness and strength, has few impurities such as surfactants, and is useful for such purposes as electronic materials, polishing materials, paints, drugs, inks and the like, as well as for polishing of magnetic disks, wafers and the like.
Further, it is another object of the present invention to provide a CMP slurry used for polishing of wafers, that can achieve polishing at an adequate rate without producing scratches in the polishing surfaces of wafer working films. It is yet another object of the present invention to provide a polishing process for wafer surfaces that comprises a step of polishing working films on wafers using the CMP slurry. Further, it is another object of the invention to provide a manufacturing process of a semiconductor device using the CMP slurry.
SUMMARY OF THE INVENTION
According to the present invention, the aforementioned objects of the invention are achieved by providing the following aqueous Dispersion, CMP slurry, a polishing Process for Wafer Surfaces, and a process for manufacture of a semiconductor device.
An aqueous dispersion characterized by containing polymer particles with a crosslinked structure and a mean particle size of 0.13-0.8 &mgr;m.
An aqueous dispersion according to claim
1
, wherein said polymer is produced by copolymerization of 5-80 wt % of a crosslinkable monomer and 20-95 wt % of another monomer.
An aqueous dispersion according to claim
2
, wherein a surfactant is also contained , and said surfactant content is no greater than 0.15 wt % .
An aqueous, wherein said polymer particles have a hydrophilic group.
An aqueous dispersion, wherein said hydrophilic group is at least
Hattori Masayuki
Hayasaka Nobuo
Iio Akira
Matsui Yukiteru
Minamihaba Gaku
Eley Timothy V.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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