Semiconductor device manufacturing: process – Chemical etching – Combined with the removal of material by nonchemical means
Reexamination Certificate
2000-03-17
2004-05-25
Norton, Nadine (Department: 1765)
Semiconductor device manufacturing: process
Chemical etching
Combined with the removal of material by nonchemical means
C438S693000, C051S309000
Reexamination Certificate
active
06740590
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to an aqueous dispersion containing polymer particles and inorganic particles. The polymer particles and inorganic particles in the aqueous dispersion of the present invention are included as composite particles (aggregates). The composite particles of the present invention have adequate strength and hardness and excellent heat resistance, and the aqueous dispersion can be utilized for cosmetics, electronic materials, magnetic materials, coating materials, paints, optical materials, catalysts, photocatalysts, electronic material film lubricants, diagnostic agents, drugs, conductive materials, inks and the like, and can also be used as a polishing material for magnetic disks and the like.
Another aspect of the present invention relates to an aqueous dispersion for chemical mechanical polishing (hereunder referred to as “CMP”) employed in the manufacture of semiconductor devices. More specifically, the present invention relates to an aqueous dispersion that is useful for CMP of semiconductor device working films, and that contains polymer particles, inorganic particles and water, wherein the zeta potentials of the particles are of opposite signs.
Yet another aspect of the present invention relates to an aqueous dispersion containing water and composite particles that consist of polymer particles and inorganic particles bonded by electrostatic force, and to an aqueous dispersion that is suitable for CMP of semiconductor device working films.
Still another aspect of the present invention relates to an aqueous dispersion containing composite particles wherein the polymer particles and inorganic particles have zeta potentials of opposite signs and the particles are bonded by electrostatic force, and to an aqueous dispersion that is suitable for CMP of semiconductor device working films.
Still another aspect of the invention relates to a method for manufacture of semiconductor devices, and more specifically to a method for formation of embedded wiring mounted on DRAMs and high-speed logic LSIs by CMP and to a method for manufacture of semiconductor devices using the technique.
2. Prior Art
For such uses as standard particles, diagnostic agent carrier particles, lubricants and the like, it has been conventional to use polymer particles with a narrow particle size distribution obtained by copolymerizing vinyl monomers or the like, in such forms as aqueous dispersions. However, the polymer particles do not always have sufficient strength and heat resistance, and when used as standard particles or lubricants, application of excessive shear stress or exposure to high temperature can cause deformation or destruction of the particles, and therefore their uses are limited. In order to deal with these problems there have been proposed particles made of copolymers of crosslinkable vinyl monomers, for example, that are copolymerized with a high degree of crosslinking. However, particles made of such crosslinked polymers have lower hardness and insufficient heat resistance compared to inorganic-based particles, and therefore cannot be made into aqueous dispersions that are suitable for a very wide range of uses.
For uses such as electronic materials, magnetic materials, optical materials, polishing materials and the like there have been employed aqueous dispersions containing particles made of various metal compounds, and a variety of composite particles have been proposed for diverse purposes. As such types of composite particles there may be mentioned composite particles comprising iron oxide particles coated with silicon compounds, so that in production of filamentous magnetic bodies by heat treatment it is possible to prevent shape collapsing and sintering between magnetic bodies; composite particles comprising iron powder coated with copper as a high strength material for powder metallurgy; and composite particles comprising iron oxide particles coated with antimony oxide and aluminum oxide for improved heat resistance. However, since such composite particles are all composed of metal compounds, they are too hard and are not always adequately suited for diverse purposes. The development of composite particles with appropriate hardness has thus become a necessity particularly in the fields of electronic materials, magnetic materials, optical materials, polishing materials, and so forth.
Improvements in degrees of semiconductor device integration and increased multilayer wiring have led to the introduction of CMP techniques for polishing of working films and the like. As disclosed in Japanese Laid-open Patent Publication No. Sho-62-102543, No. Sho-64-55845 and No. Hei-5-275366, Japanese Patent Public Inspection No. Hei-8-510437, and Japanese Laid-open Patent Publication No. Hei-8-17831, No. Hei-8-197414 and No. Hei-10-44047, there are known methods whereby wiring is formed by embedding a wiring material such as tungsten, aluminum or copper in a hole or trench formed in the insulation film of a process wafer, and then polishing to remove the excess wiring material.
In CMP it has been conventional to use polishing materials that are aqueous dispersions containing abrasive particles made of metal oxides. However, these abrasive particles present a problem in that their high hardness creates scratches in the polishing surface. Such scratches created during the CMP step are undesirable because they lower the reliability of the resulting LSI. In order to prevent creation of such scratches, Japanese Laid-open Patent Publication No. Hei-9-285957 has proposed a polishing material comprising abrasive particles such as colloidal silica, and including scratch-preventing particles made of polyurethane resin or the like with a larger particle size than the abrasive particles. However, using polishing materials containing scratch-preventing particles with a large particle size and low hardness has resulted in the problem of vastly reduced polishing rate compared to polishing materials containing metal oxide abrasive particles.
In recent years, more attention is being focused on achieving lower permittivities of interlayer insulation films for the purpose of improving VLSI performance. For lower permittivity there have been developed interlayer insulation films comprising fluorine-containing SiO
2
(permittivity: approximately 3.3-3.5), polyimide-based resins (permittivity: approximately 2.4-3.6, trade name “PIQ” by Hitachi Chemical Industries Co., Ltd.; trade name “FLARE” by Allied Signal Corporation, and the like), benzocyclobutene (permittivity: approximately 2.7, trade name “BCB” by Dow Chemical Corporation, and the like), hydrogen-containing SOG (permittivity: approximately 2.5-3.5) and organic SOG (permittivity: approximately 2.9, trade name “HSGR7” by Hitachi Chemical Industries Co., Ltd.) and the like, instead of high-permittivity SiO
2
films. However, because these insulation films have lower mechanical strength than SiO
2
films and are soft and brittle, polishing by using conventional aqueous dispersions containing inorganic particles has resulted in wire breakage by creation of scratches, and this has led to further decreasing yields.
Japanese Laid-open Patent Publication No. Hei-7-86216 describes a polishing material 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 semiconductor device working films can prevent generation of scratches in polishing surfaces. However, abrasive particles made of such organic polymer compounds have low hardness, and polishing materials containing these abrasive particles as main components also give vastly lower polishing rates compared to polishing materials containing abrasive particles made of metal oxides.
Thus, the materials described in these publications cannot achieve highly reliable high-speed polishing of working films in the manufacture of semiconductor devices, nor do they allow highly efficient fabrica
Hattori Masayuki
Iio Akira
Matsui Yukiteru
Minamihaba Gaku
Okumura Katsuya
Deo Duy-Vu
Kabushiki Kaisha Toshiba
Norton Nadine
Oblon, McClelland, Maier & Neustadt, P.C.
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