Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K13/00—Etching, surface-brightening or pickling compositions
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K3/00—Materials not provided for elsewhere
  • C09K3/14—Anti-slip materials; Abrasives
  • C09K3/1454—Abrasive powders, suspensions and pastes for polishing
  • C09K3/1463—Aqueous liquid suspensions
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09G—POLISHING COMPOSITIONS; SKI WAXES
  • C09G1/00—Polishing compositions
  • C09G1/02—Polishing compositions containing abrasives or grinding agents
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P52/00—Grinding, lapping or polishing of wafers, substrates or parts of devices
  • H10P52/40—Chemomechanical polishing [CMP]
  • H10P52/403—Chemomechanical polishing [CMP] of conductive or resistive materials
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P95/00—Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass
  • H10P95/06—Planarisation of inorganic insulating materials
  • H10P95/062—Planarisation of inorganic insulating materials involving a dielectric removal step

Definitions

• the present invention relates to compositions which are useful as slurries used during the chemical-mechanical polishing of substrates, especially those comprised of silica, a metal, titanium and/or titanium nitride. Description of Related Art
• Conventional polishing compositions or slurries generally consist of a solution which contains abrasive particles.
• the part, or substrate is bathed or rinsed in the slurry while an elastomeric pad is pressed against the substrate and the pad and substrate are moved relative to each other.
• the abrasive particles are pressed against the substrate under load and the lateral motion of the pad causes the abrasive particles to move across the substrate surface, resulting in wear and volumetric removal of the substrate surface.
• the rate of surface removal is determined solely by the degree of applied pressure, the velocity of pad rotation and the chemical activity of the slurry particle. Enhancement of the chemical activity of the polishing particle has been the basis of numerous patents, for example USP 4959113 (Roberts) and USP 5382272 (Cook et al.) both assigned to Rodel, Inc., Newark, Delaware.
• polishing rates are to add components to the slurries which by themselves are corrosive to the substrate and/or the oxide of the substrate. When used together with abrasive particles, substantially higher polishing rates may be achieved.
• CMP chemical-mechanical polishing
• This process often termed chemical-mechanical polishing (CMP) is a preferred technique for polishing of semiconductors and semiconductor devices, particularly integrated circuits.
• additives are introduced to the slurries which accelerate the dissolution of the metal component and/or the oxide of the metal component in the polishing of dielectric/metal composite structures such as interconnect vias in integrated circuit structures.
• the purpose of this and other related techniques is to preferentially remove the metal portion of the circuit so that the resulting surface becomes coplanar with an insulating or dielectric feature, typically composed of SiO 2 . This process is termed planarization.
• titanium/titanium nitride films are used to promote adhesion of tungsten and aluminum to silicon oxide insulating layers.
• Rutten et al. (“Pattern Density Effects in Tungsten CMP", June 27-29, 1995 VMIC Conference, ISMIC - 104/95/0491 ) discusses the problems encountered when planarizing a structure in which tungsten, titanium and titanium nitride are used.
• the titanium/titanium nitride layer should be removed at a rate comparable to the rate for tungsten removal, however, titanium is a very non-corrosive material. It does not oxidize easily and, therefore, is difficult to remove.
• the objective of the present invention is to find slurry compositions which are particularly effective on a composite comprising silica, a metal, and titanium in some form.
• An aqueous slurry which is useful for the chemical- mechanical polishing of substrates containing titanium comprising: water, submicron abrasive particles, an oxidizing agent, and a compound which is a mono-, di-, or tri- substituted phenol wherein at least one of the substituted functional groups is polar.
• Examples of such functional groups are hydroxyl, nitro, amine, carboxyl, sulfo and phospho groups.
• a method of chemical-mechanical polishing of substrates containing titanium with a polishing slurry comprising: water, submicron abrasive particles, an oxidizing agent, and a compound which is a mono-, di-, or tri- substituted phenol wherein at least one of the substituted fundtional groups is polar.
• a polishing slurry comprising: water, submicron abrasive particles, an oxidizing agent, and a compound which is a mono-, di-, or tri- substituted phenol wherein at least one of the substituted fundtional groups is polar.
• functional groups are hydroxyl, nitro, amine, carboxyl, sulfo and phospho groups.
• the submicron abrasive particles in the compositions of the present invention may be comprised of any of the oxides used for chemical-mechanical polishing such as alumina, silica, ceria, and zirconia.
• Abrasive particles can be used in slurries for CMP at about 0.01 % to about 15% by weight. Generally they are used at concentrations of about 1 % to about 10% by weight.
• Alumina is a preferred abrasive particle. Most preferred is alumina at about 5% to about 7% by weight.
• the oxidizing agent in the compositions of the present invention may be comprised of any of the common oxidizing agents such as nitrates, iodates, chlorates, perchlorates, chlorites, sulphates, persulphates, peroxides, ozonated water, and oxygenated water.
• Oxidizing agents can be used in slurries for CMP at concentrations of about 0.01 % to about 7% by weight. Generally they are used at concentrations of about 1 % to about 7% by weight.
• An iodate is a preferred oxidizing agent. Most preferred is potassium iodate at about 2% to about 4% by weight.
• compositions of this invention may optionally further comprise compounds which act as complexing agents or chelating agents for SiO 2 These are described in great detail in U. S. Patent 5391258 and U. S. Patent 5476606. These compounds must have at least two acid groups present in the structure which can affect complexation to the silica. Acid species are defined as those functional groups having a dissociable proton. These include, but are not limited to, carboxyl, hydroxyl, sulfo and phospho groups. Carboxyl and hydroxyl groups are preferred as these are present in the widest variety of effective species.
• Particularly effective are structures which possess two or more carboxyl groups with hydroxyl groups in an alpha position, such as straight chain mono- and di-carboxylic acids and salts including, for example, malic acid and malates, tartaric acid and tartarates and gluconic acid and gluconates. Also effective are tri- and polycarboxylic acids and salts with secondary or tertiary hydroxyl groups in an alpha position relative to a carboxyl group such as citric acid and citrates.
• benzene ring such as ortho di- and polyhydroxybenzoic acids and acid salts, phthalic acid and acid salts, pyrocatecol, pyrogallol, gallic acid and gallates and tannic acid and tannates.
• These complexing agents may be used in slurries for CMP at about 0.1 % to about 7% by weight. Preferably they are used at about 2% to about 4% by weight.
• the mono-, di-, or tri-substituted phenol compound which provides the high rate of removal of titanium and other metals in the composites may also be compounds which suppress the rate of removal of silica as defined in U. S. Patent 5,391 ,258 and U. S. Patent 5,476,606.
• compositions of this invention may be adjusted by the addition of an acid or a base to the composition.
• Generally compositions used for CMP of titanium and other metals have a pH in the range of about 1 to about 7. If a compound to suppress the rate of removal of silica is being used, which will have at least two dissociable acid groups, the pH of the polishing composition may be adjusted so that the pKa of the first dissociable acid is maintained to be not substantially larger than the pH of the polishing composition.
• EXAMPLE 1 8 inch wafers with a surface of 8000 Angstroms tungsten/400 Angstroms
• Ti 3 N 4 /250 Angstroms Ti were polished on a Westech 372U polishing machine under the following conditions: pressure 7psi, carrier 50rpm, table 40rpm, back pressure 3psi using an IC1000-P/Suba TM IV pad (available from Rodel, Inc., Newark, Delaware).
• the control slurry no.1 comprised about 3% potassium iodate, about 3% ammonium hydrogen phthalate , about 5% submicron alumina, the remainder being deionized water.
• the pH of slurry no. 1 is about 4.
• Slurry no.2 is comprised of about 2% potassium iodate, about 1 % salicylic acid, and about 5% submicron alumina.
• the pH of slurry no.2 and the following slurries no.3, 4 and 5 is about 3.5. pH adjustment is made by the addition of an acid (nitric acid) or a base (ammonium hydroxide) as required.
• Slurry no.3 was the same as slurry no.2 with the addition of about 3% hydrogen peroxide added as a 30% solution of hydrogen peroxide in water. Table 1 shows resulting clear times for all three layers, for the tungsten layer, and for the two layers containing titanium.
• polar such as salicylic acid and it's derivatives

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Treatment Of Semiconductor (AREA)

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• 1997
  • 1997-07-08 US US08/889,338 patent/US5770103A/en not_active Expired - Fee Related
• 1998
  • 1998-07-07 JP JP11508826A patent/JP2001500188A/ja not_active Withdrawn
  • 1998-07-07 EP EP98933192A patent/EP0931118A4/en not_active Withdrawn
  • 1998-07-07 KR KR1019997001866A patent/KR20000068476A/ko not_active Withdrawn
  • 1998-07-07 WO PCT/US1998/013991 patent/WO1999002623A1/en not_active Ceased

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