Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F1/00—Etching metallic material by chemical means
  • C23F1/10—Etching compositions
  • C23F1/14—Aqueous compositions
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
  • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
  • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
  • H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
  • H01L21/321—After treatment
  • H01L21/32115—Planarisation
  • H01L21/3212—Planarisation by chemical mechanical polishing [CMP]
• • 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
• • 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
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F3/00—Brightening metals by chemical means

Definitions

• compositions which are useful as slurries used during the chemical-mechanical polishing of substrates especially those comprised of silica, titanium and titanium nitride.
• 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.
• polishing rate is determined solely by the degree of applied pressure, the velocity of pad rotation and the chemical activity of the slurry particle.
• a means of increasing polishing rates is to add components to the slurries which by themselves are corrosive to the substrate. When used together with abrasive particles, substantially higher polishing rates may be achieved.
• This process often termed chemical-mechanical polishing (CMP) is a preferred technique for polishing of semiconductors and semiconductor devices, particularly integrated circuits. Often additives are introduced to the slurries which accelerate the dissolution 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 to silicon oxide insulating layers.
• 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 titanium.
• An aqueous slurry is provided which is useful for the chemical-mechanical polishing of substrates containing titanium comprising: water, submicron abrasive particles, an oxidizing agent, and a combination of complexing agents comprising a phthalate compound and a compound which is a di- or tri-carboxylic acid with at least one hydroxyl group in an alpha position relative to one of the carboxyl 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 combination of complexing agents comprising a phthalate compound and a compound which is a di- or tri- carboxylic acid with at least one hydroxyl group in an alpha position relative to one of the carboxyl groups is also provided.
• Carboxylate 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 carboxylate 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 carboxylic group such as citric acid and citrates.
• structures which possess two or more carboxylate 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.
• 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 are used in slurries for CMP at about 2% to about 7% by weight.
• a phthalate compound is used in combination with other complexing agents which are di- or tri- carboxylic acids with at least one hydroxyl group in an alpha position relative to one of the carboxyl groups to enhance the rate of removal of titanium.
• the phthalate compound may be added to the composition as a phthalate, such as potassium hydrogen phthalate, or it may be generated in the composition as shown in the examples by the addition of phthalic anhydride and ammonia to generate ammonium hydrogen phthalate.
• 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 are used in slurries for CMP at about 1% to about 15% by weight.
• Alumina is a preferred abrasive particle. Most preferred is alumina at about 7% by weight.
• the oxidizing agents in the compositions of the present invention may be comprised of nitrates, iodates, chlorates, perchlorates, chlorites, persulfates, sulfates or peroxides.
• oxidizing agents are used in slurries for CMP at about 2% to about 7% by weight.
• An iodate is a preferred oxidizing agent. Most preferred is potassium iodate at about 3% by weight.
• EXAMPLE 1 8 inch wafers were polished on a Westech 372U polishing machine (available from IPEC Planar) under the following conditions: pressure 7psi, carrier 50rpm, table 40rpm, back pressure 3psi using an IClOOO-P/SubaTM IV pad (available from Rodel, Inc., Newark, Delaware).
• a polishing slurry of the following composition (by weight) was used during the polishing of these wafers: 3.1% phthalic anhydride, 3.14% potassium iodate, 1.23% of a 29% ammonia solution, 6.86% submicron alumina and 85.67% deionized water.
• Three types of wafers were polished under the above conditions.
• Wafers of the same type as described in Example 1 were polished in the same polishing machine and at the same polishing conditions as in Example 1.
• the slurry was different than the one in Example 1 only in that 20% of the phthalic anhydride on a molar basis was replaced by malic acid.
• the complexing agent in the slurry comprised a 4 to 1 ratio of phthalate to malic acid on a molar basis.
• the clear times were 35 sec for the 400 Angstrom Ti layer, 160sec for the 2000 Angstrom Ti layer, and 205 sec for the W/TiN/Ti combined surface layer.
• EXAMPLE 3 Wafers of the same type as described in Example 1 were polished in the same polishing machine and at the same polishing conditions as in Example 1.
• the slurry was different that the one in Example 1 only in that 20% of the phthalic anhydride on a molar basis was replaced by citric acid.
• the clear times were 30sec for the 400 Angstrom Ti layer, 140sec for the 2000 Angstrom Ti layer, and 220sec for the W/TiN/Ti combined surface layer.
• the mole ratio of (a) phthalate to (b) the compound which is a di- or tri-carboxylic acid with at least one hydroxyl group in an alpha position relative to one of the carboxyl groups may be about 1 : 1 to about 10 : 1.
• a preferred range of ratios of (a) to (b) is from about 2: 1 to about 7:1.
• a most preferred ratio is about 4: 1.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• General Physics & Mathematics (AREA)
• Manufacturing & Machinery (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Power Engineering (AREA)
• Mechanical Treatment Of Semiconductor (AREA)
• Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)

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Publications (1)

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Cited By (11)

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• 1997
  • 1997-03-17 US US08/819,236 patent/US5756398A/en not_active Expired - Fee Related
• 1998
  • 1998-03-16 JP JP54067198A patent/JP2001516383A/ja not_active Ceased
  • 1998-03-16 DE DE69809228T patent/DE69809228T2/de not_active Expired - Fee Related
  • 1998-03-16 KR KR1019997008406A patent/KR20000076305A/ko not_active Ceased
  • 1998-03-16 WO PCT/US1998/005107 patent/WO1998041671A1/en not_active Ceased
  • 1998-03-16 EP EP98911675A patent/EP0985059B1/en not_active Expired - Lifetime

Patent Citations (4)

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