EP4634324A1 - Amphiphilic abrasive particles and their use for chemical mechanical planarization - Google Patents

Amphiphilic abrasive particles and their use for chemical mechanical planarization

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Publication number
EP4634324A1
EP4634324A1 EP23904305.2A EP23904305A EP4634324A1 EP 4634324 A1 EP4634324 A1 EP 4634324A1 EP 23904305 A EP23904305 A EP 23904305A EP 4634324 A1 EP4634324 A1 EP 4634324A1
Authority
EP
European Patent Office
Prior art keywords
group
abrasive particles
colloidally stable
atoms
amphiphilic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP23904305.2A
Other languages
German (de)
French (fr)
Inventor
Gerhard Jonschker
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Versum Materials US LLC
Original Assignee
Versum Materials US LLC
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Filing date
Publication date
Application filed by Versum Materials US LLC filed Critical Versum Materials US LLC
Publication of EP4634324A1 publication Critical patent/EP4634324A1/en
Pending legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B37/00—Lapping machines or devices; Accessories
    • B24B37/04—Lapping machines or devices; Accessories designed for working plane surfaces
    • B24B37/042—Lapping machines or devices; Accessories designed for working plane surfaces operating processes therefor
    • B24B37/044—Lapping machines or devices; Accessories designed for working plane surfaces operating processes therefor characterised by the composition of the lapping agent
    • 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
    • C09K3/1436—Composite particles, e.g. coated particles
    • 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
    • C23F3/04—Heavy metals
    • C23F3/06—Heavy metals with acidic solutions

Definitions

  • This invention relates to colloidally stable amphiphilic abrasive particles, chemical mechanical planarization (CMP) compositions, chemical mechanical planarization (CMP) methods, and chemical mechanical planarization (CMP) systems.
  • CMP chemical mechanical planarization
  • the amphiphilic abrasive particles have highly unpolar (or non-polar) and inert surface towards silicon oxide (TECS) films (deposited using tetraethyl orthosilicate as the precursor) while are water dispersible and colloidally stable.
  • the amphiphilic abrasives particles have low silanol density since silanol groups have been converted with inert silanes and positive charge at acidic low pH range.
  • the amphiphilic abrasive particles are useful to suppress the CMP polishing on silicon oxide, silicon nitride, or polysilicon.
  • CMP chemical mechanical planarization
  • Semiconductor devices have structured layers, and multilevel interconnects comprised of stacked thin-films consisting of one or more of the following materials: titanium (Ti), titanium nitride (TiN), tantalum (Ta), aluminum-copper (Al-Cu), aluminum-silicon (Al Si), copper (Cu), tungsten (W), doped polysilicon(poly-Si), and various combinations thereof.
  • SUBSTITUTE SHEET (RULE 26)
  • transistors or groups of transistors are isolated from one another, often through the use of trenches filled with an insulating material such as silicon dioxide, silicon nitride, and/or polysilicon.
  • an insulating material such as silicon dioxide, silicon nitride, and/or polysilicon.
  • the depositions of the semiconductor device are done with a variety of methods, and after each step a CMP process is done to ensure that the deposited layers are flat and have a surface roughness in the lower nm scale.
  • CMP utilizes the interplay of chemical and mechanical action to achieve the planarity of the to-be-polished surfaces.
  • Chemical action is provided by a chemical composition, also referred to as CMP slurry, CMP formulation, or CMP composition.
  • Mechanical action is majorly carried out by a polishing pad which is typically pressed onto the to-be-polished surface and mounted on a moving platen. The movement of the platen is usually linear, rotational or orbital.
  • a rotating wafer holder brings the to-be-polished wafer in contact with a polishing pad.
  • the CMP composition is usually applied between the to-be-polished wafer and the polishing pad.
  • CMP Chemical-mechanical planarization
  • the present invention provides amphiphilic abrasive particles with a highly unpolar and inert surface towards silicon oxide; and also provides CMP polishing compositions, methods and systems using the amphiphilic abrasive particles.
  • the present invention provides a colloidally stable amphiphilic abrasive dispersion which contains amphiphilic abrasive particles.
  • CMP compositions, methods, and systems using the colloidally stable amphiphilic abrasive dispersion are also provided.
  • the colloidally stable amphiphilic abrasive particles are provided.
  • the amphiphilic abrasive particles have both hydrophilic moieties and the hydrophobic moieties on the surfaces, thus have a highly unpolar and inert surface towards silicon oxide.
  • the amphiphilic abrasive particles in the dispersion are colloidally stable.
  • Each of the hydrophilic moieties independently includes but is not limited to at least one selected from the group consisting of a N-containing group selected from the group comprising amine and substituted amines; amino group, ammonium; ammonium group and substituted ammonium group which includes but is limited to alkylammonium
  • SUBSTITUTE SHEET (RULE 26) group comprising alkyl having ⁇ 20 C atoms; ⁇ 10 C atoms or ⁇ 4 C atoms; sulfonium; phosphonium; sulfate; sulfonate; phosphate; hydroxy; epoxy; carboxy; ether; polyether; or polyether groups; preferably the N-containing group.
  • Each of the hydrophilic moieties independently includes but is not limited to at least one selected from the group consisting of amine, amino group, ammonium, alkylammonium group comprising alkyl having ⁇ 20 C atoms; ⁇ 10 C atoms or ⁇ 4 C atoms.
  • the hydrophilic moieties can be aminogroups; and the hydrophobic moieties can be trimethylsilane-groups.
  • the colloidally stable amphiphilic abrasive particles have a ratio of hydrophilic moieties vs the hydrophobic moieties ranges from 1 .00 : 0.01 to 1 .00:10.00, 1 .00 : 0.25 to 1 .00 : 5:00, 1 :00:0.30 to 1 :00:3:00, 1.00 : 0.40 to 1 .00 : 2.50, or 1 .00 : 0.50 to 1 .00 : 2.00.
  • the colloidally stable amphiphilic abrasive particles have any size distribution including but are not limited to monomodal, bimodal or multimodal; any shape including but are not limited to spherical, elongated or branched, and a mean particle size (MPS) ranging from 1 -500 nm, 2-300 nm, 5-200 nm, 10-150 nm, or 20-100 nm dispersed in a solvent comprising water.
  • the MPS can be measured by Dynamic Light Scattering (DLS).
  • a method of making colloidally stable amphiphilic abrasive particles comprising the steps of: a. providing base abrasive particles having reactive M-OH groups on surfaces and the base abrasive particles are dispersed in solvent; b. modifying surfaces of the base abrasive particles with a first step surface modifier having at least one hydrophilic group and at least one first reactive group capable to form a covalent bond with the reactive M-OH groups to obtain one-step modified abrasive particles; c.
  • M in the reactive M-OH groups is selected from the group comprising metals or semimetals including but are not limited to Si, Ce, Al, Zr, and hybrids and/or mixtures of metals and semimetals;
  • X in the reactive X-OH groups is selected from the group consisting of Si, Ce, Al, Zr, C, P, N, hybrids and/or mixtures thereof;
  • the solvent is selected from the group consisting of water, alcohol, ketone, ester, ether, glycol, and combinations thereof.
  • the at least one first reactive group and the at least one second reactive group is independently selected from the group consisting of si-alkoxides, si-halogenides (chlorides preferred), oximates, acetates, si-hydroxides; and combinations thereof; preferably siliciummethoxides and siliciumethoxides.
  • the first step surface modifier includes but is not limited to silanes containing at least one hydrophilic group and the second step surface modifier includes but is not limited to silanes containing at least one hydrophobic group.
  • the at least one hydrophilic group includes but is not limited to N-containing group selected from the group comprising amines; substituted amines; amino group; ammonium; ammonium groups and substituted ammonium groups which include but are limited to alkylammonium group comprising alkyl having ⁇ 20 C atoms, ⁇ 10 C atoms or ⁇ 4 C atoms; sulfonium; phosphonium; sulfate; sulfonate; phosphate; hydroxy; epoxy; carboxy; ether; polyether groups; combinations thereof; preferably a N-containing group selected from the group comprising amine, amino group, ammonium, or alkylammonium group.
  • N-containing group selected from the group comprising amines; substituted amines; amino group; ammonium; ammonium groups and substituted ammonium groups which include but are limited to alkylammonium group comprising alkyl having ⁇ 20 C atoms, ⁇ 10 C atoms or ⁇ 4 C
  • the first step surface modifier is also capable to react among themselves to form a covalently bonded polymeric shell (crosslinked shell) around the base abrasive particles.
  • the second step surface modifier includes but is not limited to the silanes having at least one hydrophobic groups include but are not limited to methyl, ethyl, propyl, butyl, phenyl, benzyl, tolyl, or xylyl groups.
  • the second step surface modifier includes but is not limited to silanes having at least two, preferably at least three hydrophobic groups comprising alkyl having ⁇ 20 C atoms, ⁇ 10 C atoms or ⁇ 4 C atoms; or aryl having ⁇ 20 C atoms or ⁇ 10 C atoms; and combinations thereof.
  • Total amount of the first step surface modifiers and the second step surface modifiers includes but is not limited to 0.01 -1 .0 mmol/g (mass of abrasives calculated as dry matter), 0.025-0.8 mmol/g, 0.05 - 0.5 mmol/g, or 0.1 - 0.4 mmol/g.
  • the first step surface modifier includes but is not limited to amino-polyether silanes, betain-type silanes, 3-aminopropyl- derivatives of ethoxy- or methoxysilanes, for example, 3-aminopropylmethyldimethoxysilane, and combinations thereof; preferably 3- aminopropylmethyldimethoxysilane.
  • the first step surface modifiers can be used in any mixture with other functional or non-functional reactants like tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, and combinations thereof.
  • Examples of the second step surface modifiers include but are not limited to trimethylmethoxysilane, trimethylethoxysilane, dimethylphenylmethoxysilane, diphenylsilanediol, diphenyldimethoxysilane, methylphenyldimethoxysilane, dimethyldimethoxysilane, hexamethyldisilazane, hexamethyldisiloxane, dimethylethylmethoxysilane, dimethyloctylmethoxysilane, dimethyloctadecylchlorosilane, dimethylhexadecylmethoxysilane, dimethyl(methylphenyl)methoxysilane, potassium- tri methylsilanoate, triethylmethoxysilane, and combinations thereof.
  • Preferred second step surface modifiers are trimethylmethoxysilane, trimethylethoxysilane, and combinations thereof.
  • a CMP polishing composition comprising the colloidally stable amphiphilic abrasive particles described above dispersed in water; water soluble solvent includes but is not limited to alcohols, ethers, ketones; and mixtures thereof.
  • the CMP polishing composition can optionally comprise at least one of: organic and inorganic salt as colloidal stabilizer; catalyst including but is not limited to fluoride ions, metal salts or metal alkoxides like titaniumisopropoxide; acid/base pH buffer agent; biocide; oxidizer; catalyst; chelating agents;
  • SUBSTITUTE SHEET (RULE 26) dishing and erosion inhibitors; and corrosion inhibitor;
  • CMP chemical mechanical polishing
  • the CMP compositions using the colloidally stable, amphiphilic abrasive particle dispersion offer a high removal rate of tungsten (W), suppressed removal rate of TECS, thus an excellent W:TEOS selectivity for chemical mechanical planarization a tungsten surface (that is, W CMP), especially at acidic low pH.
  • This invention relates to colloidally stable amphiphilic abrasive particles, the Chemical Mechanical Polishing (CMP) composition (also known as slurry or formulation), methods, and systems using the colloidally stable amphiphilic abrasive particle dispersion which contains amphiphilic abrasive particles are provided.
  • CMP Chemical Mechanical Polishing
  • This invention provides colloidally stable amphiphilic abrasive dispersion that is used in the CMP composition.
  • Colloidally stable means that the inventive abrasive particles do not gel, precipitate or show a change in mean particle size ( MPS measured by DLS) of more than 10% within 30 days when stored at room temperature as dispersion (20wt.% solids) in a solvent including but not being limited to water; water soluble solvent includes but is not limited to alcohols, ethers, ketones; and mixtures thereof; at a pH which leads to a zetapotential of either > +25 mV or ⁇ -25 mV.
  • the amphiphilic abrasive particles in the dispersion have highly unpolar and inert surface towards silicon oxide while is colloidally stable, colloidally stable refers to solvent dispersible, where the solvent includes but is not limited to water; water soluble solvent includes but is not limited to alcohols, ethers, ketones; and mixtures thereof.
  • the abrasives particles have silanol groups converted with inert silanes; and thus, have low silanol density and positive charge at acidic low pH range.
  • the abrasive particles provide high selectivity, especially for tungsten CMP (W CMP) applications.
  • colloidally stable amphiphilic abrasive particles are obtained through a 2 steps surface modification or treatment process in present invention.
  • the base or unmodified abrasive particles (the most left circles), such as silica, have a surface which is very hydrophilic, covered with Si-OH (silanol) and Si-O-Si- (siloxane) groups, and can carry positive or negative charges depending on the pH.
  • the first step surface modification for example with a first step surface modifier such as aminosilane reacting covalently with Si-OH groups on the surface of a base abrasive particle, will attach hydrophilic (or polar) and/or charged groups to the surface of the abrasive particles.
  • a first step surface modifier such as aminosilane reacting covalently with Si-OH groups on the surface of a base abrasive particle
  • the first step surface modification can alsolead, depending on the applied amount of the first step surface modifier and due to the reactions among the first step surface modifier to the formation of a continuous polysiloxane crosslinked or network shell around the base abrasive particles.
  • the first step surface modification can result in either a partial surface modification, leaving parts of the base abrasive surface unmodified, or in the formation of a polysiloxane crosslinked shell, which covers and modifies the whole surface of the base abrasive particle, as shown in the following illustrations.
  • Illustration A shows a surface modification where a crosslinked shell (such as polyorganosiloxane shell) is formed around the base abrasive particles due to the reactions among the first step surface modifiers themselves and resulting in forming a covalently bonded polymeric crosslinked shell around the base abrasive particles after the first modification step.
  • This shell still comprises residual silanol groups on the surface which can be reacted with the second surface modifier(s) in the second modification step.
  • Illustration B shows a surface modification where only part of original silanol groups from part of the base abrasive particle surface has reacted with the first step surface modifiers, wherein some of the originally present silanol groups are unreacted. These silanol groups and potentially new silanol groups which were created by the surface modification step one can then be reacted in modification step two with the second step surface modifier(s).
  • Step 1 surface modification in praxis is not complete, either because of cost or for sterical reasons, there are plenty residual Si-OH groups (the leftover Si-OH groups) on the surface after the modification.
  • the modifying silanes also can hardly cover the access to the polar Si-O-Si network. So, there can be enough “polarity” present on the surface to foster unwanted interaction with the polar silicon oxides when silicon oxides should not be attacked by the abrasive particles.
  • the residual Si-OH groups can be modified by a second step surface modifier which is typically small, highly hydrophobic reactant to attach hydrophobic (or unpolar) groups to the surface of the abrasive particles.
  • silica is modified in a waterborne dispersion with small, hydrophobic molecules like trimethylchlorosilane, the colloidal dispersion will likely become unstable, and the silica will agglomerate and eventually precipitate.
  • the first step surface modification introduces a permanently hydrophilic (polar) groups (can be ionic and/or non-ionic) to the surface of the base particle to have a good compatibility with water and a high colloidal stability, especially when the first step surface modification comprises charged groups which repel similarly charged particles from each other.
  • polar polar
  • the abrasives are prepared for the second step of the modification. It is preferred to use small molecules in the second step of the modification, so that they can reach all accessible silanol groups and effectively occupy space on the abrasive surface and shield substantial part of hydrophilic surface moieties underneath. It is preferred that the majority (such as >50 %, >60%, or > 70%) of accessible silanol groups and other polar moieties on the surface of the abrasives are either converted or shielded.
  • Hydrophilic (polar) groups in the first modification step are typically attached to alkyl spacers having a certain length (typically >2 C-atoms) and show enough mobility so that they cannot be completely covered by the second surface modification step and maintain a high colloidal stability.
  • the second step surface modification a significant portion of the accessible silanol groups on the surface of the base silica are either converted by reaction with the used first step surface modifier such as silane(s) or shielded from any interaction with to-be-planarized surfaces.
  • the nature of the amphiphilic abrasive’s surface can be changed completely to be a defined or balanced mixture of introduced hydrophilic moieties (from the first surface treatment) and hydrophobic moieties (from the second surface treatment) and can be essentially free from the original hydrophilic moieties which were able to interact undesirably with for example, TEOS surfaces in a CMP application.
  • the total amount of the first step surface modifiers and the second step surface modifiers ranges from 0.01 -1 .0 mmol/g (mass of abrasives calculated as dry matter), 0.025-0.8 mmol/g, 0.05 - 0.5 mmol/g, or 0.1 - 0.4 mmol/g.
  • amphiphilic mixed hydrophilic and hydrophobic particles.
  • SUBSTITUTE SHEET typically have properties of being compatible with both polar and unpolar liquids and they can act as emulsifier. It is thus believed that these amphiphilic abrasive particles could also show advantages in applications for example, for spin-on-carbon CMP and other CMP applications in which unpolar components play a role.
  • the interaction of the inventive amphiphilic abrasive particles with to-be-preserved surface during CMP can be reduced to a very low extent and thus provide polishing selectivity, for instance, excellent “stop-on silicon oxide” performance in W-CMP.
  • the inventive amphiphilic abrasive particles also have outstanding colloidal stability.
  • the ratio of hydrophilic(polar) moieties from the first modification step and hydrophobic (unpolar) moieties from the second modification step can be 1 .00 : 0.01 to 1 .00:10.00, 1 .00 : 0.25 to 1 .00 : 5:00, 1 :00:0.30 to 1 :00:3:00, 1 .00 : 0.40 to 1 .00 : 2.50, or 1.00 : 0.50 to 1.00 : 2.00.
  • Starting base or unmodified abrasives particles have reactive M- OH groups on their surface with M being metals or semimetals including but are not limited to Si, Ce, Al, Zr, and hybrids/mixtures of metals and/or semimetals.
  • Examples of base or unmodified abrasives particles include but are not limited to silica, ceria, silica and ceria hybrids (silica modified by ceria or ceria modified by silica, zirconium silicate, carbides or nitrides.
  • Preferred base abrasives are SiO 2 -comprising abrasives such as pure silica, doped silica or multi-component silicates.
  • More preferred base abrasives are non-spherically shaped colloidal silica as described in WO2022226471 A1 .
  • Base abrasives can come in a dispersed, agglomerated or dry form, as long they can be treated as described by the two surface modification steps and yield a colloidal stable amphiphilic abrasive dispersion.
  • Base abrasives should be dispersed prior to the first surface modification step in a suitable solvent (or mixture) and substantially deagglomerated to a desirable size
  • SUBSTITUTE SHEET (RULE 26) distribution usually has at least one dimension ⁇ 500nm, preferably ⁇ 200 nm, more preferably ⁇ 150 nm; before doing surface modifications.
  • Base particles must be dispersed in a solvent or solvent mixture which allows the first and the second step surface modifications to be done in a colloidally stable state.
  • Solvent compositions can change and can be changed after the first step and before and/or after the second step for a smooth process and colloidally stable amphiphilic abrasive dispersions.
  • the typical and preferred solvent mixture are water/alcohol mixtures of various ratios which dissolves the surface modifiers.
  • Ethanol is the most preferred alcohol.
  • suitable organic solvents are acetone, diethylether, propylenglycoldimethylether, propylenglycolmonoacetylester, isopropanol, n-propanol, propylenglycolmonomethylether.
  • alkaline conditions are preferred, however under acidic conditions good results can also be obtained.
  • pH adjuster which can be either removed from the reaction mixture for example, by applying a vacuum or to use pH adjuster which later are desired components of the to-be formulated CMP slurries.
  • Typical preferred pH adjuster is HNOs or NH 3 .
  • Catalysts can also be used to foster the reaction.
  • Suitable catalysts include but are not limited to fluoride ions or metal salts or metal alkoxides like titaniumisopropoxide.
  • the first step surface modifiers can be any reactants which are capable to form a covalent bond with surface M-OH groups of the unmodified base abrasives, wherein M-OH groups is selected from the group comprising metals or semimetals including but are not limited to Si, Ce, Al, Zr, and hybrids and/or mixtures of metals and semimetals. M-OH groups are acting as linking groups with M as the linking atom.
  • the linking atom M here is an atom links or bonds the abrasive surface and hydrophilic moieties through a covalent bond.
  • the first step surface modifier can be a single reactant or a mixture of reactants.
  • the first step surface modifier is a hydrophilic modifier comprises hydrophilic groups, which can be covalently attached to the linking group, Si preferred, by alkyl- and/or aryl groups which also may contain heteroatoms.
  • the hydrophilic group may be anionic, cationic, zwitterionic (inner salt) or nonionic in nature.
  • the hydrophilic group may be anionic, cationic or nonionic depending on the pH of the solvent.
  • Preferred hydrophilic groups are N-containing groups like amines, amino group, ammonium or alkylammonium groups.
  • hydrophilic groups include but are not limited to amines, substituted amines, amino group, ammonium and substituted ammonium groups, sulfonium, phosphonium, sulfate, sulfonate, phosphate, hydroxy, epoxy, carboxy, ether or polyether groups.
  • Examples of the first step surface modifiers include but are not limited to silanes containing hydrophilic groups and at least one reactive group which is capable to form a covalent bond with the abrasive surface groups.
  • Examples are amino-polyether silanes and betain-type silanes.
  • hydrophilic group attached to one linking group which reacts with the abrasive surface.
  • the more than one hydrophilic group can be the same or different types, for example, anionic + cationic, anionic + nonionic, cationic + nonionic.
  • the first step surface modifier which is a hydrophilic surface modifier has at least one reactive group which is capable to form a covalent bond with the abrasive surface groups.
  • the reactive group of the surface modifier can be any group which can be bond cleaved under the process conditions and thereby promotes a covalent bond between
  • SUBSTITUTE SHEET (RULE 26) the abrasive surface and the modifier or is directly capable of reacting with groups on the abrasive surface.
  • Examples of typical reactive groups include but are not limited to Si-alkoxides, Si-halogenides (chlorides preferred), oximates, acetates or Si-hydroxides. Preferred examples are siliciummethoxides and siliciumethoxides.
  • Preferred first step surface modifiers are the 3-aminopropyl- derivatives of ethoxy- or methoxysilanes like for example, 3-aminopropylmethyldimethoxysilane.
  • the first step surface modifiers can also be used in any mixture with other functional or non-functional reactants like tetramethoxysilane, tetraethoxysilane methyltrimethoxysilane, methyltriethoxysilane, or the combinations thereof.
  • the ratio of the first step modifier and the functional or non-functional reactants includes but is not limited to 9.9 : 1 to 0.1 : 9.9, preferably 9:1 to 1 :9.
  • the one-step modified abrasive particles are obtained after the first step modification.
  • the surfaces of the one-step modified abrasive particles comprise reactive group of X-OH groups wherein the X in the reactive X-OH groups includes but is not limited to the group consisting of Si, Ce, Al, Zr, C, P, N, hybrids and/or mixtures thereof.
  • X-OH groups are acting as linking groups with X as the linking atom.
  • the linking atom here is an atom links or bonds the abrasive surface and hydrophobic moieties through a covalent bond.
  • the second step surface modifiers include but are not limited to reactants which are capable to form a covalent bond with surface X-OH groups of the one-step modified abrasive particles.
  • the second step surface modifier can be a single reactant or a mixture of reactants.
  • the second step surface modifier is a hydrophobic modifier which comprises hydrophobic groups.
  • the reactive group of the second surface modifier towards the surface of the abrasives can be any group which can be cleaved under the process conditions and thereby promotes a covalent bond between the one-step modified abrasive particles surfaces and the second step surface modifier or is directly capable of reacting with groups on the one-step modified abrasive particles surfaces.
  • SUBSTITUTE SHEET (RULE 26)
  • Examples of typical reactive groups include but are not limited to Si-alkoxides, Si-halogenides (chlorides preferred), oximates, acetates, or Si-hydroxides, silazanes, silanoates (e.g., KOSi(CH 3 )3) or siloxanes.
  • Preferred examples are siliciummethoxides, siliciumethoxides and silazanes.
  • the second step surface modifiers typically carry no functional group on their alkyl- or aryl group.
  • the second step surface modifiers comprise at least 2 alkyl- and/or aryl groups covalently bonded to a linking atom X (for example, silicon atom), preferably 3 alkyl- and/or aryl groups.
  • Alkyl groups have a length of ⁇ 20 C atoms, preferred ⁇ 10 C atoms and more preferred ⁇ 4 C atoms.
  • Aryl groups can carry aliphatic substituents and have in total ⁇ 20 C atoms, preferred ⁇ 10 C atoms, and more preferred ⁇ 8 C atoms.
  • Examples of a linking atom can be Si, Ce, Al, Zr, C, P, and N atoms.
  • Examples of the second step surface modifiers include but are not limited to silanes containing hydrophobic groups, at least one reactive group which is capable to form a covalent bond with the one-step modified abrasive particles surface groups.
  • Examples of the second step surface modifiers include but are not limited to trimethylmethoxysilane, trimethylethoxysilane, dimethylphenylmethoxysilane, diphenylsilanediol, diphenyldimethoxysilane, methylphenyldimethoxysilane, dimethyldimethoxysilane, hexamethyldisilazane, hexamethyldisiloxane, dimethylethylmethoxysilane, dimethyloctylmethoxysilane, dimethyloctadecylchlorosilane, dimethylhexadecylmethoxysilane, dimethyl(methylphenyl)methoxysilane, potassium- trimethylsilanoate, triethylmethoxysilane, and mixtures thereof.
  • the first step and the second step surface modifications can be done completely separately with an undefined pause and/or other operations in between like distillation, concentration, filtration, purification, ion-exchange, and the like.
  • the first step and the second step surface modifications can be done under same or different conditions, such as, at different pHs, in different solvent mixtures, at different temperatures, with different catalysts, and different reaction times.
  • Each modification step is a stand-alone process which can and should be run under the optimal conditions for the individual reaction.
  • the first step and the second step surface modifications can also be done immediately one after another without any change in pH, solvent, temperature, or catalyst.
  • first step and the second step modifications one after another, and preferably not to begin the second step surface modification before it is confirmed that the first step surface modification is almost complete, for example, checking by NMR- or IR measurements. This is to make sure that after the first step surface modification, the abrasive surface is hydrophilic enough to remain stable during the reaction with the hydrophobic second modifier.
  • each surface modification step there might be an optional aging step at a defined temperature between 0°C and the boiling point of the used solvent mixture.
  • an optional aging step is preferred to ensure completion of the reaction, followed by the removal of volatile organic components of the reaction mixture and optionally replace it by water.
  • the second surface modification is preferably done to an extent so that the colloidal stability of the abrasive dispersion is not affected and that a minimum of silicon oxide removal rate is achieved.
  • a minimum of the hydrophilic modifier content in the first modification is required to ensure colloidal stability.
  • a minimum of the second step hydrophobic modifier content is determined by the high or maximum selectivity. Too much hydrophobic modifier would lead to agglomeration.
  • the invented amphiphilic abrasive particles are colloidally stable amphiphilic abrasive particles have surface comprising hydrophilic moieties and hydrophobic moieties.
  • the hydrophilic moieties can be aminogroups; and the hydrophobic moieties can be trimethylsilane-groups.
  • the colloidally stable amphiphilic abrasive particles have a ratio of hydrophilic moieties vs the hydrophobic moieties ranges from 1 .00 : 0.01 to 1 .00:10.00, 1 .00 : 0.25 to 1 .00 : 5:00, 1 :00:0.30 to 1 :00:3:00, 1.00 : 0.40 to 1 .00 : 2.50, or 1 .00 : 0.50 to 1 .00 : 2.00.
  • the colloidally stable amphiphilic abrasive dispersion refers to the amphiphilic abrasive particles having any size distribution including but are not limited to monomodal, bimodal or multimodal; any shape including but are not limited to spherical, elongated or branched, and a size ranging from 1 -500 nm, 2-300 nm, 5-200 nm, 10-150 nm, or 20-100 nm dispersed in a solvent comprising water.
  • colloidally stable amphiphilic abrasive particles wherein surfaces of the colloidally stable amphiphilic abrasive particles comprise hydrophilic moieties and hydrophobic moieties; and the colloidally stable amphiphilic abrasive particles have highly unpolar.
  • each of the hydrophilic group contains at least one selected from the group comprising a N-containing group selected from the group comprising amines and substituted amines; amino group; ammonium; ammonium group and substituted ammonium group which includes but is limited to alkylammonium group comprising alkyl having ⁇ 20 C atoms; ⁇ 10 C atoms or ⁇ 4 C atoms; sulfonium; phosphonium; sulfate; sulfonate; phosphate; hydroxy; epoxy; carboxy; ether; polyether; or polyether groups; preferably the N-containing group; and each of the hydrophilic moieties independently contains at least one selected from the group comprising alkyl having ⁇ 20 C atoms, ⁇ 10
  • SUBSTITUTE SHEET (RULE 26) C atoms or ⁇ 4 C atoms; aryl having ⁇ 20 C atoms, ⁇ 10 C atoms, or ⁇ 8 C atoms; and combinations thereof.
  • more than one hydrophilic moieties and/or more than one hydrophobic moieties can be attached to a linking atom selected from the group consisting of Si, Ce, Al, Zr, C, P, and N atoms; wherein the linking atom links or bonds hydrophilic moieties and/or hydrophobic moieties to the surface of each colloidally stable amphiphilic abrasive particle through covalent bonds.
  • the colloidally stable amphiphilic abrasive particles have the hydrophilic moieties being silanes having amino-groups; and the hydrophobic moieties being trimethylsilane-groups; and the colloidally stable amphiphilic abrasive particles have a highly unpolar and inert surface towards silicon oxide.
  • the colloidally stable amphiphilic abrasive particles have a ratio of hydrophilic moieties vs the hydrophobic moieties ranges from 1 .00 : 0.01 to 1 .00:10.00, 1 .00 : 0.25 to 1 .00 : 5:00, 1 :00:0.30 to 1 :00:3:00, 1.00 : 0.40 to 1 .00 : 2.50, or 1 .00 : 0.50 to 1 .00 : 2.00.
  • each of the colloidally stable amphiphilic abrasive particles can be a covalently bonded polymeric crosslinked shell, such as a polyorganosiloxane crosslinked shell.
  • the M in the reactive M-OH groups is selected from the group comprising metals or semimetals including but are not limited to Si, Ce, Al, Zr, and hybrids and/or mixtures of metals and semimetals;
  • the X in the reactive X-OH groups is selected from the group consisting of Si, Ce, Al, Zr, C, P, N, hybrids and/or mixtures thereof;
  • the solvent is selected from the group consisting of water, alcohol preferably ethanol, ketone, ester, ether, glycol, and combinations thereof; preferably combinations of water and alcohol.
  • the at least one first reactive group or the at least one second reactive group is independently selected from the group consisting of si-alkoxides, si-halogenides (chlorides preferred), oximates, acetates, si-hydroxides; and combinations thereof; preferably siliciummethoxides and siliciumethoxidesthe.
  • the first step surface modifier is selected from silanes having the at least one hydrophilic group and the second step surface modifier is selected from silanes having the at least one hydrophobic group.
  • the first step surface modifier comprises at least one hydrophilic group which includes but is limited to the group comprising a N-containing group selected from the group comprising amines and substituted amines; amino group, ammonium; ammonium group and substituted ammonium group which includes but is limited to alkylammonium group comprising alkyl having ⁇ 20 C atoms; ⁇ 10 C atoms or ⁇ 4 C atoms; sulfonium; phosphonium; sulfate; sulfonate; phosphate; hydroxy; epoxy; carboxy; ether; polyether; or polyether groups; preferably a N-containing group selected from the group comprising amine, amino group, ammonium, and alkylammonium group.
  • a hydrophilic group which includes but is limited to the group comprising a N-containing group selected from the group comprising amines and substituted amines; amino group, ammonium; ammonium group and substituted ammonium group which includes but is limited to alkyl
  • a crosslinked shell (a covalently bonded polymeric shell, such as polyorganosiloxane shell) can be formed around the base abrasive particles in step b. due to the reactions among the first step surface modifiers themselves. This shell still comprises residual X-OH groups on the surface which can be reacted with the second surface modifier(s) in step c.
  • the second step surface modifier comprises at least one hydrophobic group which includes but is limited to alky group having ⁇ 20 C atoms, ⁇ 10 C atoms, or ⁇ 4 C atoms; and aryl has ⁇ 20 C atoms, ⁇ 10 C atoms, or ⁇ 8 C atoms.
  • the second step surface modifier comprises at least two, preferably at least three hydrophobic groups comprising alkyl having ⁇ 20 C atoms, ⁇ 10 C atoms or ⁇ 4 C
  • SUBSTITUTE SHEET (RULE 26) atoms; aryl having ⁇ 20 C atoms, ⁇ 10 C atoms, or ⁇ 8 C atoms; and combinations thereof.
  • the total amount of the first step surface modifiers and the second step surface modifiers ranges from 0.01 -1 .0 mmol/g (mass of abrasives calculated as dry matter), 0.025-0.8 mmol/g, 0.05 - 0.5 mmol/g, or 0.1 - 0.4 mmol/g.
  • the method further comprises step d after step c: keeping water as only dispersion after the second step surface modification.
  • CMP polishing composition comprising the colloidally stable amphiphilic abrasive particles described above dispersed in water; water soluble solvent includes but is not limited to alcohols, ethers, ketones; and mixtures thereof.
  • the CMP polishing composition can optionally comprise at least one of: organic and inorganic salt as colloidal stabilizer; catalyst including but is not limited to fluoride ions, metal salts or metal alkoxides like titaniumisopropoxide; acid/base pH buffer agent; biocide; oxidizer; catalyst; chelating agents; dishing and erosion inhibitors; and corrosion inhibitor;
  • CMP chemical mechanical polishing
  • the CMP compositions using the colloidally stable, amphiphilic abrasive particle dispersion offer a high removal rate of tungsten (W), suppressed removal rate of TEOS, thus an excellent W:TEOS selectivity for chemical mechanical planarization a tungsten surface (that is, W CMP), especially at acidic low pH.
  • TEOS silicon oxide films by Chemical Vapor Deposition (CVD) using tetraethyl orthosilicate as the precursor
  • Wt.% weight percentage (of a listed component)
  • Removal Rate (RR) (film thickness before polishing - film thickness after polishing)/polish time.
  • Polishing Pad Polishing pad, IC1010 was used during CMP, supplied by
  • Conditioning Disk 3M A122 Disk was used which was provided by 3M company.
  • a or A angstrom(s) - a unit of length
  • BP back pressure, in psi units
  • DF Down force: pressure applied during CMP, unit: psi
  • Wt. % weight percentage (of a listed component)
  • W TEOS Selectivity: (removal rate of W)/ (removal rate of TEOS)
  • HDP high density plasma deposited TEOS
  • TEOS or HDP Removal Rates Measured TEOS or HDP removal rate at a given down pressure.
  • Aggregation ratio is a descriptor of the shape of non- spherical particles. It is the quotient of the secondary particle size, determined by DLS and the calculated primary particle size, which is derived from the BET surface area as it is commonly known in the state of the art.
  • ResMap CDE model 168, manufactured by Creative Design Engineering, Inc, 20565 Alves Dr., Cupertino, CA, 95014.
  • the ResMap tool is a four-point probe sheet resistance tool. Forty-nine-point diameter scan at 5mm edge exclusion for film was taken.
  • the CMP tool that was used is a 200mm Mirra, or 300mm Reflexion manufactured by Applied Materials, 3050 Boweres Avenue, Santa Clara, California, 95054.
  • An IC1000 pad supplied by DOW, Inc, 451 Bellevue Rd., Newark, DE 19713 was used on platen 1 for blanket and pattern wafer studies.
  • the IK4250UH pad or other pad was broken in by conditioning the pad for 18 mins. At 7 lbs. down force on the conditioner. To qualify the tool settings and the pad break-in two tungsten monitors and two TEOS monitors were polished with Versum® STI2305 composition, supplied by Versum Materials Inc. at baseline conditions.
  • Polishing experiments were conducted using PECVD or LPCVD or HD TEOS wafers. These blanket wafers were purchased from Silicon Valley Microelectronics, 2985 Kifer Rd., Santa Clara, CA 95051.
  • silica nanoparticle suspension in water (911 .50 g; 978.49 mmol SiO2; elongated shaped, aggregation ratio: 2.86; 95.8 nm size as measured by DLS; pH 10.5) was heated while stirring to 70°C.
  • the yield was the suspension of colloidally stable, one step modified elongated silica nanoparticles of 97.1 nm size (measured by DLS)
  • silica nanoparticle suspension in water (911 .50 g; 978.49 mmol SiC>2, elongated shaped, aggregation ratio: 2.86; 95.8 nm size as measured by DLS, pH 10.5) was heated while
  • the yield was the suspension of colloidally stable, two steps modified elongated silica nanoparticles of 98.1 nm size (measured by DLS)
  • silica nanoparticle suspension in water (911.50 g; 978.49 mmol SiO 2 elongated shaped, aggregation ratio: 2.86; 95.8 nm size as measured by DLS, pH 10.5) was heated while stirring to 70°C. While stirring is continued, a mixture of (3- aminopropyl)dimethoxymethylsilane (1.22 ml; 7.06 mmol), tetraethoxysilane (14.07 ml; 63.51 mmol;) and ethanol (140.57 ml; 2410.57 mmol; 2.46 aq.) is added within 6 hours.
  • the yield was the suspension of colloidally stable, two steps modified elongated silica nanoparticles of 99.7 nm size (measured by DLS)
  • silica nanoparticle suspension in water (564.97 g; 1664.33 mmol SiO?; elongated shaped, aggregation ratio 2.71 ; 91.6 nm size measured by DLS; pH 10.5) was heated while stirring to 70°C. While stirring is continued, a mixture of 3-aminopropyltriethoxysilane (5.59 ml; 24.00 mmol), tetraethoxysilane (47.87 ml; 216.00 mmol) and ethanol (468.07 ml; 8.03 mol) was added while stirring over the course of 12 hours.
  • the yield was the suspension of colloidally stable, one step modified elongated silica nanoparticles of 94.5 nm size (measured by DLS)
  • silica nanoparticle suspension in water (564.97 g; 1664.33 mmol SiO?; elongated shaped, aggregation ratio 2.71 ; 91.6 nm size measured by DLS; pH 10.5) was heated while stirring to 70°C. While stirring is continued, a mixture of 3-aminopropyltriethoxysilane (5.59 ml; 24.00 mmol), tetraethoxysilane (47.87 ml; 216.00 mmol) and ethanol (468.07 ml; 8.03 mol) was added while stirring over the course of 12 hours.
  • silica nanoparticle suspension (564.97 g; 1664.33 mmol SiO2; elongated shaped, aggregation ratio 2.71 ; 91 .6 nm size measured by DLS; pH 10.5) was heated while stirring to 70°C. While stirring is continued, a mixture of 3-aminopropyltriethoxysilane (5.59 ml; 24.00 mmol), tetraethoxysilane (47.87 ml; 216.00 mmol) and ethanol (468.07 ml; 8.03 mol) was added while stirring over the course of 12 hours.
  • the yield was the suspension of colloidally stable, two steps modified elongated silica nanoparticles of 98.6 nm size (measured by DLS)
  • silica nanoparticle suspension in water (482.43 g; 1170 mmol SiO 3 ; elongated shaped, aggregation ratio 2.98; 86.2 nm size measured by DLS; pH 4.3) was heated while stirring to 70°C.
  • Stream 1 consists of (3-aminopropyl)dimethoxymethylsilane (5.81 ml; 33.60 mmol), dissolved in 95 ml methanol.
  • Stream 2 consists of nitric acid, 65% (2.58 ml; 36.96 mmol), dissolved in 98.2 ml methanol.
  • the yield was the suspension of colloidally stable, one step modified elongated silica nanoparticles of 87.5 nm size (measured by DLS).
  • silica nanoparticle suspension in water (482.43 g; 1170 mmol SiO2; elongated shaped aggregation ratio 2.98; 86.2 nm size measured by DLS; pH 4.3) was heated while stirring to 70°C.
  • Stream 1 consists of (3-aminopropyl)dimethoxymethylsilane (5.81 ml; 33.60 mmol), dissolved in 95 ml methanol.
  • Stream 2 consists of nitric acid, 65% (2.58 ml; 36.96 mmol), dissolved in 98.2 ml methanol.
  • the yield was the suspension of colloidally stable, two steps modified elongated silica nanoparticles of 87.9 nm size (measured by DLS).
  • silica nanoparticle suspension in water (482.43 g; 1170 mmol SiO2; elongated shaped aggregation ratio 2.98; 86.2 nm size measured by DLS; pH 10.5) was heated while stirring to 70°C.
  • the yield was highly turbid, agglomerated silica dispersion in water which was not colloidally stable and could not be used for CMP slurry formulation.
  • the modified silica nanoparticle suspensions obtained above were used to formulate W-CMP slurries.
  • the slurries contain 0.1 wt. % abrasives (PL-2C), 0.01 wt.% ferric nitrate (iron (III) nitrate), 0.08 wt.% malonic acid, 0.02 wt.% 1 ,8- Diazabicyclo[5.4.0]undec-7-ene (DBU), 2.0 wt.% hydrogen peroxide, 0.1 wt.% glycine and in water with pH adjusted to 2.3 with nitric acid.
  • P-2C 0.1 wt. % abrasives
  • ferric nitrate iron (III) nitrate
  • malonic acid 0.02 wt.% 1 ,8- Diazabicyclo[5.4.0]undec-7-ene
  • DBU Diazabicyclo[5.4.0]undec-7-ene

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Abstract

Colloidally stable amphiphilic abrasive particle dispersion containing amphiphilic abrasive particles is provided. The surface of each colloidally stable amphiphilic abrasive particle comprises hydrophilic moieties and hydrophobic moieties. Chemical mechanical planarization (CMP) polishing compositions, methods and systems using the colloidally stable amphiphilic abrasive particle dispersion are also provided. The CMP compositions offer a high removal rate of tungsten (W), suppressed removal rate of silicon oxide (TEOS), thus an excellent W:TEOS selectivity for chemical mechanical planarization a tungsten surface.

Description

TITLE OF THE INVENTION:
AMPHIPHILIC ABRASIVE PARTICLES AND
THEIR USE FOR CHEMICAL MECHANICAL PLANARIZATION
CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63/387,535 [63/387,523] filed on December 15, 2022, which is incorporated herein by reference as if fully set forth.
BACKGROUND OF THE INVENTION
[0002] This invention relates to colloidally stable amphiphilic abrasive particles, chemical mechanical planarization (CMP) compositions, chemical mechanical planarization (CMP) methods, and chemical mechanical planarization (CMP) systems.
[0003] More specifically, chemical mechanical planarization (CMP) polishing compositions, methods and systems using the colloidally stable amphiphilic abrasive particle dispersion which contains amphiphilic abrasive particles are provided. The amphiphilic abrasive particles have highly unpolar (or non-polar) and inert surface towards silicon oxide (TECS) films (deposited using tetraethyl orthosilicate as the precursor) while are water dispersible and colloidally stable. In addition, the amphiphilic abrasives particles have low silanol density since silanol groups have been converted with inert silanes and positive charge at acidic low pH range. The amphiphilic abrasive particles are useful to suppress the CMP polishing on silicon oxide, silicon nitride, or polysilicon.
[0004] In the semiconductor industry, chemical mechanical planarization (CMP) is a well-known technology applied in fabricating advanced photonic, microelectromechanical, and micro-electronic materials and devices, such as semiconductor wafers.
Semiconductor devices have structured layers, and multilevel interconnects comprised of stacked thin-films consisting of one or more of the following materials: titanium (Ti), titanium nitride (TiN), tantalum (Ta), aluminum-copper (Al-Cu), aluminum-silicon (Al Si), copper (Cu), tungsten (W), doped polysilicon(poly-Si), and various combinations thereof.
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SUBSTITUTE SHEET (RULE 26) In addition, transistors or groups of transistors are isolated from one another, often through the use of trenches filled with an insulating material Such as silicon dioxide, silicon nitride, and/or polysilicon. The depositions of the semiconductor device are done with a variety of methods, and after each step a CMP process is done to ensure that the deposited layers are flat and have a surface roughness in the lower nm scale.
[0005] CMP utilizes the interplay of chemical and mechanical action to achieve the planarity of the to-be-polished surfaces. Chemical action is provided by a chemical composition, also referred to as CMP slurry, CMP formulation, or CMP composition. Mechanical action is majorly carried out by a polishing pad which is typically pressed onto the to-be-polished surface and mounted on a moving platen. The movement of the platen is usually linear, rotational or orbital.
[0006] In a typical CMP process step, a rotating wafer holder brings the to-be-polished wafer in contact with a polishing pad. The CMP composition is usually applied between the to-be-polished wafer and the polishing pad.
[0007] Chemical-mechanical planarization (CMP) is a process which is used in the fabrication of electronic parts like memory- or microprocessor chips. Structured layers are deposited by a variety of methods and after each step a CMP process is done to ensure that the deposited layers are flat and have a surface roughness in the lower nm scale.
[0008] Typically, different materials are deposited on top of each other in highly complicated structures and the CMP process must be precisely stopped when the to be planarized material is removed and the underlying material is exposed. This is done by thoroughly controlling the planarization time on the one hand, but the CMP slurry is also formulated in a way that it shows a maximum selectivity in aggressiveness between the to-be-planarized and the to-be-preserved material.
[0009] So, it is the combination of an effectively high removal rate of the to-be- planarized material and a very low removal rate of the to-be-preserved material which defines the effectiveness of a CMP slurry.
[0010] Besides various additives and various pH which can be used to tailor slurry selectivity, it is the CMP abrasive material which is responsible to a great extent for the removal rates and selectivity of a slurry, as disclosed in US9028572.
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SUBSTITUTE SHEET (RULE 26) [0011] This is especially true for, for example, W-CMP applications in which the slurry should show a high removal rate against the oxidized W-metal and a very low removal rate against the silicon oxide which should remain mostly unharmed.
[0012] Even after known surface modification treatments, the typical CMP abrasive has many polar groups on its surface which can form electrostatical- or hydrogen bonds with silica and other polar surfaces, which results in unwanted high silicon oxide removal rates. So, W-CMP slurry formulators struggle to manage high selectivities with the existing abrasive materials.
[0013] Currently available CMP abrasives do not show an intrinsically high selectivity. They must be mixed with many additives to realize the desired selectivity which on the other hand can show problems regarding slurry stability or reduction of removal rates of the to-be-planarized material.
[0014] The present invention provides amphiphilic abrasive particles with a highly unpolar and inert surface towards silicon oxide; and also provides CMP polishing compositions, methods and systems using the amphiphilic abrasive particles. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.
Summary of The Invention
[0015] The present invention provides a colloidally stable amphiphilic abrasive dispersion which contains amphiphilic abrasive particles. CMP compositions, methods, and systems using the colloidally stable amphiphilic abrasive dispersion are also provided.
[0016] In one aspect, the colloidally stable amphiphilic abrasive particles are provided. The amphiphilic abrasive particles have both hydrophilic moieties and the hydrophobic moieties on the surfaces, thus have a highly unpolar and inert surface towards silicon oxide. The amphiphilic abrasive particles in the dispersion are colloidally stable.
[0017] Each of the hydrophilic moieties independently includes but is not limited to at least one selected from the group consisting of a N-containing group selected from the group comprising amine and substituted amines; amino group, ammonium; ammonium group and substituted ammonium group which includes but is limited to alkylammonium
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SUBSTITUTE SHEET (RULE 26) group comprising alkyl having < 20 C atoms; < 10 C atoms or < 4 C atoms; sulfonium; phosphonium; sulfate; sulfonate; phosphate; hydroxy; epoxy; carboxy; ether; polyether; or polyether groups; preferably the N-containing group.
[0018] Each of the hydrophilic moieties independently includes but is not limited to at least one selected from the group consisting of amine, amino group, ammonium, alkylammonium group comprising alkyl having < 20 C atoms; < 10 C atoms or < 4 C atoms.
[0019] As an example, the hydrophilic moieties can be aminogroups; and the hydrophobic moieties can be trimethylsilane-groups.
[0020] The colloidally stable amphiphilic abrasive particles have a ratio of hydrophilic moieties vs the hydrophobic moieties ranges from 1 .00 : 0.01 to 1 .00:10.00, 1 .00 : 0.25 to 1 .00 : 5:00, 1 :00:0.30 to 1 :00:3:00, 1.00 : 0.40 to 1 .00 : 2.50, or 1 .00 : 0.50 to 1 .00 : 2.00.
[0021] The colloidally stable amphiphilic abrasive particles have any size distribution including but are not limited to monomodal, bimodal or multimodal; any shape including but are not limited to spherical, elongated or branched, and a mean particle size (MPS) ranging from 1 -500 nm, 2-300 nm, 5-200 nm, 10-150 nm, or 20-100 nm dispersed in a solvent comprising water. The MPS can be measured by Dynamic Light Scattering (DLS).
[0022] In another aspect, there is provided a method of making colloidally stable amphiphilic abrasive particles, comprising the steps of: a. providing base abrasive particles having reactive M-OH groups on surfaces and the base abrasive particles are dispersed in solvent; b. modifying surfaces of the base abrasive particles with a first step surface modifier having at least one hydrophilic group and at least one first reactive group capable to form a covalent bond with the reactive M-OH groups to obtain one-step modified abrasive particles; c. modifying surfaces of the one-step modified abrasive particles with a second step surface modifier having at least one hydrophobic groups and having at least one second reactive group capable to form a covalent bond with reactive X-OH groups on surfaces of the one-step modified abrasive particles to obtain the amphiphilic abrasive particles;
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SUBSTITUTE SHEET (RULE 26) wherein the M in the reactive M-OH groups is selected from the group comprising metals or semimetals including but are not limited to Si, Ce, Al, Zr, and hybrids and/or mixtures of metals and semimetals; the X in the reactive X-OH groups is selected from the group consisting of Si, Ce, Al, Zr, C, P, N, hybrids and/or mixtures thereof; and the solvent is selected from the group consisting of water, alcohol, ketone, ester, ether, glycol, and combinations thereof.
[0023] The at least one first reactive group and the at least one second reactive group is independently selected from the group consisting of si-alkoxides, si-halogenides (chlorides preferred), oximates, acetates, si-hydroxides; and combinations thereof; preferably siliciummethoxides and siliciumethoxides.
[0024] Preferably the first step surface modifier includes but is not limited to silanes containing at least one hydrophilic group and the second step surface modifier includes but is not limited to silanes containing at least one hydrophobic group.
[0025] The at least one hydrophilic group includes but is not limited to N-containing group selected from the group comprising amines; substituted amines; amino group; ammonium; ammonium groups and substituted ammonium groups which include but are limited to alkylammonium group comprising alkyl having < 20 C atoms, < 10 C atoms or < 4 C atoms; sulfonium; phosphonium; sulfate; sulfonate; phosphate; hydroxy; epoxy; carboxy; ether; polyether groups; combinations thereof; preferably a N-containing group selected from the group comprising amine, amino group, ammonium, or alkylammonium group.
[0026] The first step surface modifier is also capable to react among themselves to form a covalently bonded polymeric shell (crosslinked shell) around the base abrasive particles.
[0027] The second step surface modifier includes but is not limited to the silanes having at least one hydrophobic groups include but are not limited to methyl, ethyl, propyl, butyl, phenyl, benzyl, tolyl, or xylyl groups.
[0028] The second step surface modifier includes but is not limited to silanes having at least two, preferably at least three hydrophobic groups comprising alkyl having < 20 C atoms, < 10 C atoms or < 4 C atoms; or aryl having < 20 C atoms or < 10 C atoms; and combinations thereof.
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SUBSTITUTE SHEET (RULE 26) [0029] Total amount of the first step surface modifiers and the second step surface modifiers includes but is not limited to 0.01 -1 .0 mmol/g (mass of abrasives calculated as dry matter), 0.025-0.8 mmol/g, 0.05 - 0.5 mmol/g, or 0.1 - 0.4 mmol/g.
[0030] The first step surface modifier includes but is not limited to amino-polyether silanes, betain-type silanes, 3-aminopropyl- derivatives of ethoxy- or methoxysilanes, for example, 3-aminopropylmethyldimethoxysilane, and combinations thereof; preferably 3- aminopropylmethyldimethoxysilane.
[0031] The first step surface modifiers can be used in any mixture with other functional or non-functional reactants like tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, and combinations thereof.
[0032] Examples of the second step surface modifiers include but are not limited to trimethylmethoxysilane, trimethylethoxysilane, dimethylphenylmethoxysilane, diphenylsilanediol, diphenyldimethoxysilane, methylphenyldimethoxysilane, dimethyldimethoxysilane, hexamethyldisilazane, hexamethyldisiloxane, dimethylethylmethoxysilane, dimethyloctylmethoxysilane, dimethyloctadecylchlorosilane, dimethylhexadecylmethoxysilane, dimethyl(methylphenyl)methoxysilane, potassium- tri methylsilanoate, triethylmethoxysilane, and combinations thereof.
[0033] Preferred second step surface modifiers are trimethylmethoxysilane, trimethylethoxysilane, and combinations thereof.
[0034] In yet another aspect, there is provided a CMP polishing composition comprising the colloidally stable amphiphilic abrasive particles described above dispersed in water; water soluble solvent includes but is not limited to alcohols, ethers, ketones; and mixtures thereof.
[0035] The CMP polishing composition can optionally comprise at least one of: organic and inorganic salt as colloidal stabilizer; catalyst including but is not limited to fluoride ions, metal salts or metal alkoxides like titaniumisopropoxide; acid/base pH buffer agent; biocide; oxidizer; catalyst; chelating agents;
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SUBSTITUTE SHEET (RULE 26) dishing and erosion inhibitors; and corrosion inhibitor;
[0036] In another aspect, there is provided a method of chemical mechanical polishing (CMP) a substrate having at least one surface comprising tungsten using the chemical mechanical polishing (CMP) composition described above.
[0037] Specifically, the CMP compositions using the colloidally stable, amphiphilic abrasive particle dispersion offer a high removal rate of tungsten (W), suppressed removal rate of TECS, thus an excellent W:TEOS selectivity for chemical mechanical planarization a tungsten surface (that is, W CMP), especially at acidic low pH.
DETAILED DESCRIPTION OF THE INVENTION
[0038] This invention relates to colloidally stable amphiphilic abrasive particles, the Chemical Mechanical Polishing (CMP) composition (also known as slurry or formulation), methods, and systems using the colloidally stable amphiphilic abrasive particle dispersion which contains amphiphilic abrasive particles are provided.
[0039] This invention provides colloidally stable amphiphilic abrasive dispersion that is used in the CMP composition. Colloidally stable means that the inventive abrasive particles do not gel, precipitate or show a change in mean particle size ( MPS measured by DLS) of more than 10% within 30 days when stored at room temperature as dispersion (20wt.% solids) in a solvent including but not being limited to water; water soluble solvent includes but is not limited to alcohols, ethers, ketones; and mixtures thereof; at a pH which leads to a zetapotential of either > +25 mV or < -25 mV.
[0040] The amphiphilic abrasive particles in the dispersion have highly unpolar and inert surface towards silicon oxide while is colloidally stable, colloidally stable refers to solvent dispersible, where the solvent includes but is not limited to water; water soluble solvent includes but is not limited to alcohols, ethers, ketones; and mixtures thereof.
[0041] The abrasives particles have silanol groups converted with inert silanes; and thus, have low silanol density and positive charge at acidic low pH range. The abrasive particles provide high selectivity, especially for tungsten CMP (W CMP) applications.
[0042] These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.
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SUBSTITUTE SHEET (RULE 26) [0043] Abrasive Particles:
[0044] The colloidally stable amphiphilic abrasive particles are obtained through a 2 steps surface modification or treatment process in present invention.
[0045] The base or unmodified abrasive particles (the most left circles), such as silica, have a surface which is very hydrophilic, covered with Si-OH (silanol) and Si-O-Si- (siloxane) groups, and can carry positive or negative charges depending on the pH.
[0046] The first step surface modification, for example with a first step surface modifier such as aminosilane reacting covalently with Si-OH groups on the surface of a base abrasive particle, will attach hydrophilic (or polar) and/or charged groups to the surface of the abrasive particles.
[0047] Furthermore, the first step surface modification can alsolead, depending on the applied amount of the first step surface modifier and due to the reactions among the first step surface modifier to the formation of a continuous polysiloxane crosslinked or network shell around the base abrasive particles.
[0048] Thus, the first step surface modification can result in either a partial surface modification, leaving parts of the base abrasive surface unmodified, or in the formation of a polysiloxane crosslinked shell, which covers and modifies the whole surface of the base abrasive particle, as shown in the following illustrations.
- 8 -
SUBSTITUTE SHEET (RULE 26) [0049] Illustration A shows a surface modification where a crosslinked shell (such as polyorganosiloxane shell) is formed around the base abrasive particles due to the reactions among the first step surface modifiers themselves and resulting in forming a covalently bonded polymeric crosslinked shell around the base abrasive particles after the first modification step. This shell still comprises residual silanol groups on the surface which can be reacted with the second surface modifier(s) in the second modification step.
[0050] Illustration B shows a surface modification where only part of original silanol groups from part of the base abrasive particle surface has reacted with the first step surface modifiers, wherein some of the originally present silanol groups are unreacted. These silanol groups and potentially new silanol groups which were created by the surface modification step one can then be reacted in modification step two with the second step surface modifier(s).
[0051] If the first step (Step 1) surface modification in praxis is not complete, either because of cost or for sterical reasons, there are plenty residual Si-OH groups (the leftover Si-OH groups) on the surface after the modification. In addition, the modifying silanes also can hardly cover the access to the polar Si-O-Si network. So, there can be enough “polarity” present on the surface to foster unwanted interaction with the polar silicon oxides when silicon oxides should not be attacked by the abrasive particles.
[0052] With a second surface modification step (Step 2), the residual Si-OH groups can be modified by a second step surface modifier which is typically small, highly hydrophobic reactant to attach hydrophobic (or unpolar) groups to the surface of the abrasive particles.
[0053] Surface modifications of silica and other oxides with small, hydrophobic molecules like trimethylchlorosilane alone are used to make toners for laser printers or trickling (anti-caking) aids for hydrophobic pigments. The modified silica is rendered completely hydrophobic by the modification, and it is hardly possible to keep it in a colloidally stable dispersion in water. In fact, these treatments are also used to impart water-repelling properties to particles.
[0054] Also, if silica is modified in a waterborne dispersion with small, hydrophobic molecules like trimethylchlorosilane, the colloidal dispersion will likely become unstable, and the silica will agglomerate and eventually precipitate.
- 9 -
SUBSTITUTE SHEET (RULE 26) [0055] The present invention overcomes all these negative effects as described below.
[0056] In present invention, the first step surface modification introduces a permanently hydrophilic (polar) groups (can be ionic and/or non-ionic) to the surface of the base particle to have a good compatibility with water and a high colloidal stability, especially when the first step surface modification comprises charged groups which repel similarly charged particles from each other.
[0057] After the first step surface modification, the abrasives are prepared for the second step of the modification. It is preferred to use small molecules in the second step of the modification, so that they can reach all accessible silanol groups and effectively occupy space on the abrasive surface and shield substantial part of hydrophilic surface moieties underneath. It is preferred that the majority (such as >50 %, >60%, or > 70%) of accessible silanol groups and other polar moieties on the surface of the abrasives are either converted or shielded.
[0058] Hydrophilic (polar) groups in the first modification step are typically attached to alkyl spacers having a certain length (typically >2 C-atoms) and show enough mobility so that they cannot be completely covered by the second surface modification step and maintain a high colloidal stability.
[0059] After the second step surface modification, a significant portion of the accessible silanol groups on the surface of the base silica are either converted by reaction with the used first step surface modifier such as silane(s) or shielded from any interaction with to-be-planarized surfaces. Thus, the nature of the amphiphilic abrasive’s surface can be changed completely to be a defined or balanced mixture of introduced hydrophilic moieties (from the first surface treatment) and hydrophobic moieties (from the second surface treatment) and can be essentially free from the original hydrophilic moieties which were able to interact undesirably with for example, TEOS surfaces in a CMP application.
[0060] The total amount of the first step surface modifiers and the second step surface modifiers ranges from 0.01 -1 .0 mmol/g (mass of abrasives calculated as dry matter), 0.025-0.8 mmol/g, 0.05 - 0.5 mmol/g, or 0.1 - 0.4 mmol/g.
[0061] Since there are distinct hydrophobic and hydrophilic moieties spread over the whole surface of the two steps modified abrasive particles, so they can be called amphiphilic (mixed hydrophilic and hydrophobic) particles. The amphiphilic substances
- 10 -
SUBSTITUTE SHEET (RULE 26) typically have properties of being compatible with both polar and unpolar liquids and they can act as emulsifier. It is thus believed that these amphiphilic abrasive particles could also show advantages in applications for example, for spin-on-carbon CMP and other CMP applications in which unpolar components play a role.
[0062] By choosing the ratio of hydroph ilic(polar) moieties from the first modification step and hydrophobic (unpolar) moieties from the second modification step , the interaction of the inventive amphiphilic abrasive particles with to-be-preserved surface during CMP can be reduced to a very low extent and thus provide polishing selectivity, for instance, excellent “stop-on silicon oxide” performance in W-CMP. The inventive amphiphilic abrasive particles also have outstanding colloidal stability.
[0063] The ratio of hydrophilic(polar) moieties from the first modification step and hydrophobic (unpolar) moieties from the second modification step can be 1 .00 : 0.01 to 1 .00:10.00, 1 .00 : 0.25 to 1 .00 : 5:00, 1 :00:0.30 to 1 :00:3:00, 1 .00 : 0.40 to 1 .00 : 2.50, or 1.00 : 0.50 to 1.00 : 2.00.
[0064] More details about the process to obtain the colloidally stable amphiphilic abrasive particles are described.
[0065] Starting base or unmodified abrasives particles (or abrasives) have reactive M- OH groups on their surface with M being metals or semimetals including but are not limited to Si, Ce, Al, Zr, and hybrids/mixtures of metals and/or semimetals. Examples of base or unmodified abrasives particles include but are not limited to silica, ceria, silica and ceria hybrids (silica modified by ceria or ceria modified by silica, zirconium silicate, carbides or nitrides.
[0066] Preferred base abrasives are SiO2-comprising abrasives such as pure silica, doped silica or multi-component silicates.
[0067] More preferred base abrasives are non-spherically shaped colloidal silica as described in WO2022226471 A1 .
[0068] Base abrasives can come in a dispersed, agglomerated or dry form, as long they can be treated as described by the two surface modification steps and yield a colloidal stable amphiphilic abrasive dispersion.
[0069] Base abrasives should be dispersed prior to the first surface modification step in a suitable solvent (or mixture) and substantially deagglomerated to a desirable size
- 11 -
SUBSTITUTE SHEET (RULE 26) distribution; usually has at least one dimension <500nm, preferably <200 nm, more preferably <150 nm; before doing surface modifications.
[0070] Base particles must be dispersed in a solvent or solvent mixture which allows the first and the second step surface modifications to be done in a colloidally stable state. Solvent compositions can change and can be changed after the first step and before and/or after the second step for a smooth process and colloidally stable amphiphilic abrasive dispersions.
[0071] The typical and preferred solvent mixture are water/alcohol mixtures of various ratios which dissolves the surface modifiers. Ethanol is the most preferred alcohol.
[0072] Other possible organic solvents which can be used in a mixture with water are ketones, esters, ethers, glycols and alcohols. Examples of suitable organic solvents are acetone, diethylether, propylenglycoldimethylether, propylenglycolmonoacetylester, isopropanol, n-propanol, propylenglycolmonomethylether.
[0073] Pure water as a solvent for the modification steps is possible but not preferred, especially not for the second modification step, since the hydrophobic modifiers do not readily dissolve or disperse in water which may lead to longer process times and inhomogeneous results.
[0074] It is preferred to remove non-volatile organic components from the abrasive dispersion latest after the second step surface modification and keep essentially only water as the only dispersant in the final product.
[0075] Surface modification can be made at any suitable pH depending on the nature of the base abrasive and the reactants.
[0076] Typically, to foster the reaction between the surface groups of the abrasive particles and the reactant, alkaline conditions are preferred, however under acidic conditions good results can also be obtained.
[0077] It is preferred to use pH adjuster which can be either removed from the reaction mixture for example, by applying a vacuum or to use pH adjuster which later are desired components of the to-be formulated CMP slurries. Typical preferred pH adjuster is HNOs or NH3.
[0078] Catalysts can also be used to foster the reaction. Suitable catalysts include but are not limited to fluoride ions or metal salts or metal alkoxides like titaniumisopropoxide.
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SUBSTITUTE SHEET (RULE 26) [0079] The first step surface modifiers can be any reactants which are capable to form a covalent bond with surface M-OH groups of the unmodified base abrasives, wherein M-OH groups is selected from the group comprising metals or semimetals including but are not limited to Si, Ce, Al, Zr, and hybrids and/or mixtures of metals and semimetals. M-OH groups are acting as linking groups with M as the linking atom. The linking atom M here is an atom links or bonds the abrasive surface and hydrophilic moieties through a covalent bond.
[0080] The first step surface modifier can be a single reactant or a mixture of reactants.
[0081] The first step surface modifier is a hydrophilic modifier comprises hydrophilic groups, which can be covalently attached to the linking group, Si preferred, by alkyl- and/or aryl groups which also may contain heteroatoms.
[0082] The hydrophilic group may be anionic, cationic, zwitterionic (inner salt) or nonionic in nature. The hydrophilic group may be anionic, cationic or nonionic depending on the pH of the solvent. Preferred hydrophilic groups are N-containing groups like amines, amino group, ammonium or alkylammonium groups.
[0083] Examples of hydrophilic groups include but are not limited to amines, substituted amines, amino group, ammonium and substituted ammonium groups, sulfonium, phosphonium, sulfate, sulfonate, phosphate, hydroxy, epoxy, carboxy, ether or polyether groups.
[0084] Examples of the first step surface modifiers include but are not limited to silanes containing hydrophilic groups and at least one reactive group which is capable to form a covalent bond with the abrasive surface groups. Examples are amino-polyether silanes and betain-type silanes.
[0085] There can be more than one hydrophilic group attached to one linking group which reacts with the abrasive surface. The more than one hydrophilic group can be the same or different types, for example, anionic + cationic, anionic + nonionic, cationic + nonionic. The first step surface modifier which is a hydrophilic surface modifier has at least one reactive group which is capable to form a covalent bond with the abrasive surface groups.
[0086] The reactive group of the surface modifier can be any group which can be bond cleaved under the process conditions and thereby promotes a covalent bond between
- 13 -
SUBSTITUTE SHEET (RULE 26) the abrasive surface and the modifier or is directly capable of reacting with groups on the abrasive surface.
[0087] Examples of typical reactive groups include but are not limited to Si-alkoxides, Si-halogenides (chlorides preferred), oximates, acetates or Si-hydroxides. Preferred examples are siliciummethoxides and siliciumethoxides.
[0088] Preferred first step surface modifiers are the 3-aminopropyl- derivatives of ethoxy- or methoxysilanes like for example, 3-aminopropylmethyldimethoxysilane.
[0089] The first step surface modifiers can also be used in any mixture with other functional or non-functional reactants like tetramethoxysilane, tetraethoxysilane methyltrimethoxysilane, methyltriethoxysilane, or the combinations thereof. The ratio of the first step modifier and the functional or non-functional reactants includes but is not limited to 9.9 : 1 to 0.1 : 9.9, preferably 9:1 to 1 :9.
[0090] The one-step modified abrasive particles are obtained after the first step modification. The surfaces of the one-step modified abrasive particles comprise reactive group of X-OH groups wherein the X in the reactive X-OH groups includes but is not limited to the group consisting of Si, Ce, Al, Zr, C, P, N, hybrids and/or mixtures thereof. X-OH groups are acting as linking groups with X as the linking atom. The linking atom here is an atom links or bonds the abrasive surface and hydrophobic moieties through a covalent bond.
[0091] The second step surface modifiers include but are not limited to reactants which are capable to form a covalent bond with surface X-OH groups of the one-step modified abrasive particles.
[0092] The second step surface modifier can be a single reactant or a mixture of reactants.
[0093] The second step surface modifier is a hydrophobic modifier which comprises hydrophobic groups.
[0094] The reactive group of the second surface modifier towards the surface of the abrasives can be any group which can be cleaved under the process conditions and thereby promotes a covalent bond between the one-step modified abrasive particles surfaces and the second step surface modifier or is directly capable of reacting with groups on the one-step modified abrasive particles surfaces.
- 14 -
SUBSTITUTE SHEET (RULE 26) [0095] Examples of typical reactive groups include but are not limited to Si-alkoxides, Si-halogenides (chlorides preferred), oximates, acetates, or Si-hydroxides, silazanes, silanoates (e.g., KOSi(CH3)3) or siloxanes. Preferred examples are siliciummethoxides, siliciumethoxides and silazanes.
[0096] The second step surface modifiers typically carry no functional group on their alkyl- or aryl group.
[0097] The second step surface modifiers comprise at least 2 alkyl- and/or aryl groups covalently bonded to a linking atom X (for example, silicon atom), preferably 3 alkyl- and/or aryl groups. Alkyl groups have a length of < 20 C atoms, preferred < 10 C atoms and more preferred < 4 C atoms. Aryl groups can carry aliphatic substituents and have in total <20 C atoms, preferred < 10 C atoms, and more preferred < 8 C atoms. Examples of a linking atom can be Si, Ce, Al, Zr, C, P, and N atoms.
[0098] Examples of the second step surface modifiers include but are not limited to silanes containing hydrophobic groups, at least one reactive group which is capable to form a covalent bond with the one-step modified abrasive particles surface groups.
[0099] Examples of the second step surface modifiers include but are not limited to trimethylmethoxysilane, trimethylethoxysilane, dimethylphenylmethoxysilane, diphenylsilanediol, diphenyldimethoxysilane, methylphenyldimethoxysilane, dimethyldimethoxysilane, hexamethyldisilazane, hexamethyldisiloxane, dimethylethylmethoxysilane, dimethyloctylmethoxysilane, dimethyloctadecylchlorosilane, dimethylhexadecylmethoxysilane, dimethyl(methylphenyl)methoxysilane, potassium- trimethylsilanoate, triethylmethoxysilane, and mixtures thereof.
[00100] It is preferred to use short-chain, small molecules with only one reactive group like trimethylmethoxysilane, trimethylethoxysilane, or mixtures thereof for the second step surface modifiers. In case the reactants from the second step surface modifiers do not get a chance to react with the surface of the abrasive but two reactants react with each other, then hexamethyldisiloxane forms which is an organic solvent with a sufficiently low boiling point so that this byproduct could be removed by distillation without problems. So, even a large excess of reactants would be manageable in the reaction without the problem of accumulation of unwanted byproducts and unreacted reactants.
- 15 -
SUBSTITUTE SHEET (RULE 26) [00101] The first step and the second step surface modifications can be done completely separately with an undefined pause and/or other operations in between like distillation, concentration, filtration, purification, ion-exchange, and the like.
[00102] The first step and the second step surface modifications can be done under same or different conditions, such as, at different pHs, in different solvent mixtures, at different temperatures, with different catalysts, and different reaction times. Each modification step is a stand-alone process which can and should be run under the optimal conditions for the individual reaction.
[00103] The first step and the second step surface modifications can also be done immediately one after another without any change in pH, solvent, temperature, or catalyst.
[00104] It is preferred to do first step and the second step modifications one after another, and preferably not to begin the second step surface modification before it is confirmed that the first step surface modification is almost complete, for example, checking by NMR- or IR measurements. This is to make sure that after the first step surface modification, the abrasive surface is hydrophilic enough to remain stable during the reaction with the hydrophobic second modifier.
[00105] After each surface modification step there might be an optional aging step at a defined temperature between 0°C and the boiling point of the used solvent mixture.
[00106] After the second surface modification, an optional aging step is preferred to ensure completion of the reaction, followed by the removal of volatile organic components of the reaction mixture and optionally replace it by water.
[00107] This can be done by any suitable process like distillation or membrane filtration. It is preferred to adjust the total nonvolatile solid content of the reaction mixture to 10- 50% solids, more preferred to 20-40% solids and most preferred to 30-40 % solids.
[00108] After the second surface modification, further modifications such as, filtration, classification, ion-exchange, addition of other compounds can be done. This can be done before or after the removal of volatile organic compounds.
[00109] The second surface modification is preferably done to an extent so that the colloidal stability of the abrasive dispersion is not affected and that a minimum of silicon oxide removal rate is achieved.
- 16 -
SUBSTITUTE SHEET (RULE 26) [00110] There is a minimum total amount of surface modifiers (the first step and the second step) to give good removal rates and selectivity.
[00111] A minimum of the hydrophilic modifier content in the first modification is required to ensure colloidal stability.
[00112] A minimum of the second step hydrophobic modifier content is determined by the high or maximum selectivity. Too much hydrophobic modifier would lead to agglomeration.
[00113] The invented amphiphilic abrasive particles are colloidally stable amphiphilic abrasive particles have surface comprising hydrophilic moieties and hydrophobic moieties. As an example, the hydrophilic moieties can be aminogroups; and the hydrophobic moieties can be trimethylsilane-groups.
[00114] The colloidally stable amphiphilic abrasive particles have a ratio of hydrophilic moieties vs the hydrophobic moieties ranges from 1 .00 : 0.01 to 1 .00:10.00, 1 .00 : 0.25 to 1 .00 : 5:00, 1 :00:0.30 to 1 :00:3:00, 1.00 : 0.40 to 1 .00 : 2.50, or 1 .00 : 0.50 to 1 .00 : 2.00.
[00115] The colloidally stable amphiphilic abrasive dispersion refers to the amphiphilic abrasive particles having any size distribution including but are not limited to monomodal, bimodal or multimodal; any shape including but are not limited to spherical, elongated or branched, and a size ranging from 1 -500 nm, 2-300 nm, 5-200 nm, 10-150 nm, or 20-100 nm dispersed in a solvent comprising water.
[00116] Thus, provided here are colloidally stable amphiphilic abrasive particles, wherein surfaces of the colloidally stable amphiphilic abrasive particles comprise hydrophilic moieties and hydrophobic moieties; and the colloidally stable amphiphilic abrasive particles have highly unpolar.
[00117] Where, each of the hydrophilic group contains at least one selected from the group comprising a N-containing group selected from the group comprising amines and substituted amines; amino group; ammonium; ammonium group and substituted ammonium group which includes but is limited to alkylammonium group comprising alkyl having < 20 C atoms; < 10 C atoms or < 4 C atoms; sulfonium; phosphonium; sulfate; sulfonate; phosphate; hydroxy; epoxy; carboxy; ether; polyether; or polyether groups; preferably the N-containing group; and each of the hydrophilic moieties independently contains at least one selected from the group comprising alkyl having < 20 C atoms, < 10
- 17 -
SUBSTITUTE SHEET (RULE 26) C atoms or < 4 C atoms; aryl having < 20 C atoms, < 10 C atoms, or < 8 C atoms; and combinations thereof.
[00118] Furthermore, more than one hydrophilic moieties and/or more than one hydrophobic moieties can be attached to a linking atom selected from the group consisting of Si, Ce, Al, Zr, C, P, and N atoms; wherein the linking atom links or bonds hydrophilic moieties and/or hydrophobic moieties to the surface of each colloidally stable amphiphilic abrasive particle through covalent bonds.
[00119] The colloidally stable amphiphilic abrasive particles have the hydrophilic moieties being silanes having amino-groups; and the hydrophobic moieties being trimethylsilane-groups; and the colloidally stable amphiphilic abrasive particles have a highly unpolar and inert surface towards silicon oxide.
[00120] The colloidally stable amphiphilic abrasive particles have a ratio of hydrophilic moieties vs the hydrophobic moieties ranges from 1 .00 : 0.01 to 1 .00:10.00, 1 .00 : 0.25 to 1 .00 : 5:00, 1 :00:0.30 to 1 :00:3:00, 1.00 : 0.40 to 1 .00 : 2.50, or 1 .00 : 0.50 to 1 .00 : 2.00.
[00121] The surface of each of the colloidally stable amphiphilic abrasive particles can be a covalently bonded polymeric crosslinked shell, such as a polyorganosiloxane crosslinked shell.
[00122] Provided here is also a method of making colloidally stable amphiphilic abrasive particles, comprising the steps of: a. providing base abrasive particle having reactive M-OH groups on its surface and the base abrasive particles are dispersed in a solvent; b. modifying the surface of the base abrasive particle with a first step surface modifier having at least one hydrophilic group and least one first reactive group capable to form a covalent bond with or directly react with the reactive M-OH groups to obtain one-step modified abrasive particles; c. modifying surface of the one-step modified abrasive particles with a second step surface modifier having at least one hydrophobic group and at least one second reactive group capable to form a covalent bond with or directly react with X-OH groups on surfaces of the one-step modified abrasive particles to obtain the amphiphilic abrasive particles; wherein
- 18 -
SUBSTITUTE SHEET (RULE 26) the M in the reactive M-OH groups is selected from the group comprising metals or semimetals including but are not limited to Si, Ce, Al, Zr, and hybrids and/or mixtures of metals and semimetals; the X in the reactive X-OH groups is selected from the group consisting of Si, Ce, Al, Zr, C, P, N, hybrids and/or mixtures thereof; and the solvent is selected from the group consisting of water, alcohol preferably ethanol, ketone, ester, ether, glycol, and combinations thereof; preferably combinations of water and alcohol.
[00123] The at least one first reactive group or the at least one second reactive group is independently selected from the group consisting of si-alkoxides, si-halogenides (chlorides preferred), oximates, acetates, si-hydroxides; and combinations thereof; preferably siliciummethoxides and siliciumethoxidesthe.
[00124] The first step surface modifier is selected from silanes having the at least one hydrophilic group and the second step surface modifier is selected from silanes having the at least one hydrophobic group.
[00125] The first step surface modifier comprises at least one hydrophilic group which includes but is limited to the group comprising a N-containing group selected from the group comprising amines and substituted amines; amino group, ammonium; ammonium group and substituted ammonium group which includes but is limited to alkylammonium group comprising alkyl having < 20 C atoms; < 10 C atoms or < 4 C atoms; sulfonium; phosphonium; sulfate; sulfonate; phosphate; hydroxy; epoxy; carboxy; ether; polyether; or polyether groups; preferably a N-containing group selected from the group comprising amine, amino group, ammonium, and alkylammonium group.
[00126] A crosslinked shell (a covalently bonded polymeric shell, such as polyorganosiloxane shell) can be formed around the base abrasive particles in step b. due to the reactions among the first step surface modifiers themselves. This shell still comprises residual X-OH groups on the surface which can be reacted with the second surface modifier(s) in step c.
[00127] The second step surface modifier comprises at least one hydrophobic group which includes but is limited to alky group having < 20 C atoms, < 10 C atoms, or < 4 C atoms; and aryl has < 20 C atoms, < 10 C atoms, or < 8 C atoms.
[00128] The second step surface modifier comprises at least two, preferably at least three hydrophobic groups comprising alkyl having < 20 C atoms, < 10 C atoms or < 4 C
- 19 -
SUBSTITUTE SHEET (RULE 26) atoms; aryl having < 20 C atoms, < 10 C atoms, or < 8 C atoms; and combinations thereof.
[00129] The total amount of the first step surface modifiers and the second step surface modifiers ranges from 0.01 -1 .0 mmol/g (mass of abrasives calculated as dry matter), 0.025-0.8 mmol/g, 0.05 - 0.5 mmol/g, or 0.1 - 0.4 mmol/g.
[00130] The method further comprises step d after step c: keeping water as only dispersion after the second step surface modification.
[00131] Provided here yet is also a CMP polishing composition comprising the colloidally stable amphiphilic abrasive particles described above dispersed in water; water soluble solvent includes but is not limited to alcohols, ethers, ketones; and mixtures thereof.
[00132] The CMP polishing composition can optionally comprise at least one of: organic and inorganic salt as colloidal stabilizer; catalyst including but is not limited to fluoride ions, metal salts or metal alkoxides like titaniumisopropoxide; acid/base pH buffer agent; biocide; oxidizer; catalyst; chelating agents; dishing and erosion inhibitors; and corrosion inhibitor;
[00133] In addition, there is provided a method of chemical mechanical polishing (CMP) a substrate having at least one surface comprising tungsten using the chemical mechanical polishing (CMP) composition described above.
[00134] Specifically, the CMP compositions using the colloidally stable, amphiphilic abrasive particle dispersion offer a high removal rate of tungsten (W), suppressed removal rate of TEOS, thus an excellent W:TEOS selectivity for chemical mechanical planarization a tungsten surface (that is, W CMP), especially at acidic low pH.
- 20 -
SUBSTITUTE SHEET (RULE 26) CMP Methodology
[00135] In the examples presented below, CMP experiments were run using the procedures and experimental conditions given below.
GLOSSARY
COMPONENTS
[00136] TEOS: silicon oxide films by Chemical Vapor Deposition (CVD) using tetraethyl orthosilicate as the precursor
[00137] Wt.%: weight percentage (of a listed component)
[00138] Removal Rate (RR) = (film thickness before polishing - film thickness after polishing)/polish time.
[00139] Polishing Pad: Polishing pad, IC1010 was used during CMP, supplied by
DOW, Inc.
[00140] Conditioning Disk: 3M A122 Disk was used which was provided by 3M company.
PARAMETERS
General
[00141] A or A: angstrom(s) - a unit of length
[00142] BP: back pressure, in psi units
[00143] CMP: chemical mechanical planarization = chemical mechanical polishing
[00144] CS: carrier speed
[00145] DF: Down force: pressure applied during CMP, unit: psi
[00146] min: minute(s)
[00147] ml: milliliter(s)
[00148] mV: millivolt(s)
[00149] psi: pounds per square inch
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SUBSTITUTE SHEET (RULE 26) [00150] PS: platen rotational speed of polishing tool, in rpm (revolution(s) per minute)
[00151] SF: composition flow, ml/min
[00152] Wt. %: weight percentage (of a listed component)
[00153] W: TEOS Selectivity: (removal rate of W)/ (removal rate of TEOS)
[00154] HDP: high density plasma deposited TEOS
[00155] TEOS or HDP Removal Rates: Measured TEOS or HDP removal rate at a given down pressure.
[00156] Aggregation ratio: the aggregation ratio is a descriptor of the shape of non- spherical particles. It is the quotient of the secondary particle size, determined by DLS and the calculated primary particle size, which is derived from the BET surface area as it is commonly known in the state of the art.
Aggregation ratio = secondary particle size I primary particle size
Primary particle size = 2727 I specific surface area by BET
Metrology
[00157] Films were measured with a ResMap CDE, model 168, manufactured by Creative Design Engineering, Inc, 20565 Alves Dr., Cupertino, CA, 95014. The ResMap tool is a four-point probe sheet resistance tool. Forty-nine-point diameter scan at 5mm edge exclusion for film was taken.
CMP Tool
[00158] The CMP tool that was used is a 200mm Mirra, or 300mm Reflexion manufactured by Applied Materials, 3050 Boweres Avenue, Santa Clara, California, 95054. An IC1000 pad supplied by DOW, Inc, 451 Bellevue Rd., Newark, DE 19713 was used on platen 1 for blanket and pattern wafer studies.
[00159] The IK4250UH pad or other pad was broken in by conditioning the pad for 18 mins. At 7 lbs. down force on the conditioner. To qualify the tool settings and the pad break-in two tungsten monitors and two TEOS monitors were polished with Versum® STI2305 composition, supplied by Versum Materials Inc. at baseline conditions.
- 22 -
SUBSTITUTE SHEET (RULE 26) [00160] All polishing data in the following examples was generated on a Mirra polisher using an IC 1010 pad at a polishing downforce of 2.5 psi.
Wafers
[00161] Polishing experiments were conducted using PECVD or LPCVD or HD TEOS wafers. These blanket wafers were purchased from Silicon Valley Microelectronics, 2985 Kifer Rd., Santa Clara, CA 95051.
Abrasive Modification Experiments
Example 1 (Comparative Example)
Synthesis of polyaminoorganosiloxane-modified, elongated silica nanoparticles
[00162] In a 2 ,000 ml 4-neck flask equipped with stirrer and reflux condenser, silica nanoparticle suspension in water (911 .50 g; 978.49 mmol SiO2; elongated shaped, aggregation ratio: 2.86; 95.8 nm size as measured by DLS; pH 10.5) was heated while stirring to 70°C. While stirring is continued, a mixture of (3- aminopropyl)dimethoxymethylsilane (1.22 ml; 7.06 mmol), tetraethoxysilane (14.07 ml; 63.51 mmol;) and ethanol (140.57 ml; 2410.57 mmol; 2.46 aq.) was added within 6 hours.
[00163] Volatile organic solvents were exchanged against water by rotary evaporation, the resulting suspension of polyaminoorganosiloxane -modified, elongated silica particles was adjusted to have a pH of 2.5 with HNO3, and finally concentrated to a solids content of 20 wt.%.
[00164] The yield was the suspension of colloidally stable, one step modified elongated silica nanoparticles of 97.1 nm size (measured by DLS)
Example 2
[00165] In a 2,000 ml 4-neck flask equipped with stirrer and reflux condenser, silica nanoparticle suspension in water (911 .50 g; 978.49 mmol SiC>2, elongated shaped, aggregation ratio: 2.86; 95.8 nm size as measured by DLS, pH 10.5) was heated while
- 23 -
SUBSTITUTE SHEET (RULE 26) stirring to 70°C. While stirring is continued, a mixture of (3- aminopropyl)dimethoxymethylsilane (1.22 ml; 7.06 mmol), tetraethoxysilane (14.07 ml; 63.51 mmol;) and ethanol (140.57 ml; 2410.57 mmol; 2.46 aq.) was added within 6 hours.
[00166] In a subsequent step, a mixture of trimethylmethoxysilane (99%; 0.975 ml; 7.055 mmol;) and ethanol (16,75 ml; 287,18 mmol;) was added over the course of 6 hours while stirring at 70°C, followed by 12 hours stirring at room temperature.
[00167] Volatile organic solvents were exchanged against water by rotary evaporation, the resulting suspension of polyaminoorganosiloxane-modified, elongated silica particles was adjusted to have a pH of 2.5 with HNO3, and finally concentrated to a solids content of 20 wt.%.
[00168] The yield was the suspension of colloidally stable, two steps modified elongated silica nanoparticles of 98.1 nm size (measured by DLS)
Example 3
[00169] In a 2,000 ml 4-neck flask equipped with stirrer and reflux condenser, silica nanoparticle suspension in water (911.50 g; 978.49 mmol SiO2 elongated shaped, aggregation ratio: 2.86; 95.8 nm size as measured by DLS, pH 10.5) was heated while stirring to 70°C. While stirring is continued, a mixture of (3- aminopropyl)dimethoxymethylsilane (1.22 ml; 7.06 mmol), tetraethoxysilane (14.07 ml; 63.51 mmol;) and ethanol (140.57 ml; 2410.57 mmol; 2.46 aq.) is added within 6 hours.
[00170] In a subsequent step, a mixture of trimethylmethoxysilane (99%; (1 .95 ml; 14,11 mmol;) and ethanol (16,75 ml; 287,18 mmol;) was added over the course of 6 hours while stirring at 70°C, followed by 12 hours stirring at room temperature.
[00171] Volatile organic solvents were exchanged against water by rotary evaporation, the resulting suspension of polyaminoorganosiloxane -modified, elongated silica particles was adjusted to have a pH of 2.5 with HNO3, and finally concentrated to a solids content of 20.wt%.
[00172] The yield was the suspension of colloidally stable, two steps modified elongated silica nanoparticles of 99.7 nm size (measured by DLS)
- 24 -
SUBSTITUTE SHEET (RULE 26) Example 4 (Comparative Examples)
Synthesis of polyaminoorganosiloxane-modified, elongated silica nanoparticles
[00173] In a 2 ,000 ml 4-neck flask equipped with stirrer and reflux condenser, silica nanoparticle suspension in water (564.97 g; 1664.33 mmol SiO?; elongated shaped, aggregation ratio 2.71 ; 91.6 nm size measured by DLS; pH 10.5) was heated while stirring to 70°C. While stirring is continued, a mixture of 3-aminopropyltriethoxysilane (5.59 ml; 24.00 mmol), tetraethoxysilane (47.87 ml; 216.00 mmol) and ethanol (468.07 ml; 8.03 mol) was added while stirring over the course of 12 hours.
[00174] Volatile organic solvents were exchanged against water by rotary evaporation the resulting suspension of polyaminoorganosiloxane-modified, elongated silica particles was adjusted to have a pH of 2.5 with HNO3, and finally concentrated to a solids content of 20 wt.%.
[00175] The yield was the suspension of colloidally stable, one step modified elongated silica nanoparticles of 94.5 nm size (measured by DLS)
Example 5
[00176] In a 2,000 ml 4-neck flask equipped with stirrer and reflux condenser, silica nanoparticle suspension in water (564.97 g; 1664.33 mmol SiO?; elongated shaped, aggregation ratio 2.71 ; 91.6 nm size measured by DLS; pH 10.5) was heated while stirring to 70°C. While stirring is continued, a mixture of 3-aminopropyltriethoxysilane (5.59 ml; 24.00 mmol), tetraethoxysilane (47.87 ml; 216.00 mmol) and ethanol (468.07 ml; 8.03 mol) was added while stirring over the course of 12 hours.
[00177] In a subsequent step, a mixture of trimethylmethoxysilane (99%; (1 .658 ml; 12.00 mmol) and ethanol (16,75 ml; 287,18 mmol;) was added over the course of 6 hours while stirring at 70°C, followed by 12 hours stirring at room temperature.
[00178] Volatile organic solvents were exchanged against water by rotary evaporation, the resulting suspension of polyaminoorganosiloxane-modified, elongated silica particles was adjusted to have a pH of 2.5 with HNO3, and finally concentrated to a solids content of 20 wt.%.
- 25 -
SUBSTITUTE SHEET (RULE 26) [00179] The yield was the suspension of colloidally stable, two steps modified elongated silica nanoparticles of 96.1 nm size (measured by DLS).
Example 6
[00180] In a 2,000 ml 4-neck flask equipped with stirrer and reflux condenser, silica nanoparticle suspension (564.97 g; 1664.33 mmol SiO2; elongated shaped, aggregation ratio 2.71 ; 91 .6 nm size measured by DLS; pH 10.5) was heated while stirring to 70°C. While stirring is continued, a mixture of 3-aminopropyltriethoxysilane (5.59 ml; 24.00 mmol), tetraethoxysilane (47.87 ml; 216.00 mmol) and ethanol (468.07 ml; 8.03 mol) was added while stirring over the course of 12 hours.
[00181] In a subsequent step, a mixture of trimethylmethoxysilane (99%; (1 .658 ml; 36.00 mmol) and ethanol (50.25 ml; 861 .54 mmol;) was added over the course of 12 hours while stirring at 70°C, followed by 12 hours stirring at room temperature.
[00182] Volatile organic solvents were exchanged against water by rotary evaporation, the resulting suspension of polyaminoorganosiloxane-modified, elongated silica particles was adjusted to have a pH of 2.5 with HNO3, and finally concentrated to a solids content of 20 wt.%.
[00183] The yield was the suspension of colloidally stable, two steps modified elongated silica nanoparticles of 98.6 nm size (measured by DLS)
Example 7 (Comparative Examples)
Synthesis of polyaminoorganosiloxane-modified, elongated silica nanoparticles
[00184] In a 1 ,000 ml 4-neck flask equipped with stirrer and reflux condenser, silica nanoparticle suspension in water (482.43 g; 1170 mmol SiO3; elongated shaped, aggregation ratio 2.98; 86.2 nm size measured by DLS; pH 4.3) was heated while stirring to 70°C.
[00185] While stirring is continued, 2 streams of reactants were simultaneously added within 1 hour to the flask by precision pumps. The streams were mixed with a T- connector immediately before reaching the flask.
- 26 -
SUBSTITUTE SHEET (RULE 26) [00186] Stream 1 consists of (3-aminopropyl)dimethoxymethylsilane (5.81 ml; 33.60 mmol), dissolved in 95 ml methanol. Stream 2 consists of nitric acid, 65% (2.58 ml; 36.96 mmol), dissolved in 98.2 ml methanol.
[00187] After addition of the reactants, the mixture of the two streams was stirred for 2 hours at 70°C, then volatile reaction products were removed by rotary evaporation, and the solid content was adjusted to 20.wt% by addition of water.
[00188] The yield was the suspension of colloidally stable, one step modified elongated silica nanoparticles of 87.5 nm size (measured by DLS).
Example 8
[00189] In a 1 ,000 ml 4-neck flask equipped with stirrer and reflux condenser, silica nanoparticle suspension in water (482.43 g; 1170 mmol SiO2; elongated shaped aggregation ratio 2.98; 86.2 nm size measured by DLS; pH 4.3) was heated while stirring to 70°C.
[00190] While stirring is continued, 2 streams of reactants were simultaneously added within 1 hour to the flask by precision pumps. The streams were mixed with a T- connector immediately before reaching the flask.
[00191] Stream 1 consists of (3-aminopropyl)dimethoxymethylsilane (5.81 ml; 33.60 mmol), dissolved in 95 ml methanol. Stream 2 consists of nitric acid, 65% (2.58 ml; 36.96 mmol), dissolved in 98.2 ml methanol.
[00192] After the mixing of two streams, trimethylmethoxysilane (3.47 ml; 25.2 mmol), dissolved in 62.9 ml methanol was added to the mixture of two streams over the course of 1.5 hours.
[00193] The final mixture was stirred for another 12 hours at 70°C, then volatile reaction products were removed by rotary evaporation, and the solid content was adjusted to 20 wt.% by addition of water.
[00194] The yield was the suspension of colloidally stable, two steps modified elongated silica nanoparticles of 87.9 nm size (measured by DLS).
- 27 -
SUBSTITUTE SHEET (RULE 26) Example 9 (Comparative Examples)
[00195] In a 1 ,000 ml 4-neck flask equipped with stirrer and reflux condenser, silica nanoparticle suspension in water (482.43 g; 1170 mmol SiO2; elongated shaped aggregation ratio 2.98; 86.2 nm size measured by DLS; pH 10.5) was heated while stirring to 70°C.
[00196] Trimethylmethoxysilane (3.47 ml; 25.2 mmol), dissolved in 62.9 ml methanol was added to the reaction mixture over the course of 1 .5 hours.
[00197] The mixture was stirred for another 12 hours at 70°C, then volatile reaction products were removed by rotary evaporation.
[00198] The yield was highly turbid, agglomerated silica dispersion in water which was not colloidally stable and could not be used for CMP slurry formulation.
Chemical Mechanical Planarization (CMP) Experiments
[00199] The modified silica nanoparticle suspensions obtained above were used to formulate W-CMP slurries. The slurries contain 0.1 wt. % abrasives (PL-2C), 0.01 wt.% ferric nitrate (iron (III) nitrate), 0.08 wt.% malonic acid, 0.02 wt.% 1 ,8- Diazabicyclo[5.4.0]undec-7-ene (DBU), 2.0 wt.% hydrogen peroxide, 0.1 wt.% glycine and in water with pH adjusted to 2.3 with nitric acid.
- 28 -
SUBSTITUTE SHEET (RULE 26) [00200] The slurries and removal rates were shown in Table 1 .
Table 1
*APDMS: 3-aminopropyl)dimethoxymethylsilane;
**APTES: 3-aminopropyltriethoxysilane;
***TMMOS: trimethylmethoxysilane.
[00201] As shown in Table 1 , the slurries using two steps modified abrasive particles were very effective to suppress the TEOS removal rate while maintaining or increasing the W removal, thus increasing the W:TEOS RR selectivity.
[00202] The embodiments of this invention listed above, including the working example, are exemplary of numerous embodiments that may be made of this invention. It is contemplated that numerous other configurations of the process may be used, and the materials used in the process may be elected from numerous materials other than those specifically disclosed.
SUBSTITUTE SHEET (RULE 26)

Claims

Claims
1 . Colloidally stable amphiphilic abrasive particles, wherein surface of each colloidally stable amphiphilic abrasive particle comprises hydrophilic moieties and hydrophobic moieties.
2. The colloidally stable amphiphilic abrasive particles according to claim 1 , wherein each of the hydrophilic moieties independently comprises at least one selected from the group consisting of a N-containing group selected from the group comprising amine and substituted amines; amino group; ammonium; ammonium group and substituted ammonium group; sulfonium; phosphonium; sulfate; sulfonate; phosphate; hydroxy; epoxy; carboxy; ether; polyether; and polyether groups.
3. The colloidally stable amphiphilic abrasive particles according to any one of claims 1 -2, wherein each of the hydrophilic moieties independently comprises at least one selected from the group consisting of amine, ammonium, and alkylammonium group comprising alkyl having < 20 C atoms; < 10 C atoms or < 4 C atoms.
4. The colloidally stable amphiphilic abrasive particles according to any one of claims 1 -3, wherein each of the hydrophobic moieties independently comprises at least one selected from the group consisting of alky group having < 20 C atoms, < 10 C atoms, or < 4 C atoms; and aryl has < 20 C atoms, < 10 C atoms, or < 8 C atoms.
5. The colloidally stable amphiphilic abrasive particles according to any one of claims 1 -4, wherein each of the hydrophobic moieties independently comprises at least one selected from the group consisting of methyl, ethyl, propyl, butyl, phenyl, benzyl, tolyl, and xylyl group.
6. The colloidally stable amphiphilic abrasive particles according to any one of claims 1 -5, wherein more than one hydrophilic moieties and/or more than one hydrophobic moieties can be attached to a linking atom selected from the group consisting of Si, Ce, Al, Zr, C, P, and N atoms; wherein the linking atom links or bonds hydrophilic moieties and/or hydrophobic moieties to the surface of each colloidally stable amphiphilic abrasive particle through covalent bonds.
- 30 -
SUBSTITUTE SHEET (RULE 26) The colloidally stable amphiphilic abrasive particles according to any one of claims 1 -6, wherein the hydrophilic moieties are silanes having amino-groups; and the hydrophobic moieties are trimethylsilane-groups; and the colloidally stable amphiphilic abrasive particles have a highly unpolar and inert surface towards silicon oxide. The colloidally stable amphiphilic abrasive particles according to any one of claims 1 -7, wherein a ratio of hydrophilic moieties vs the hydrophobic moieties ranges from 1 .00 : 0.01 to 1 .00:10.00, 1 .00 : 0.25 to 1 .00 : 5:00, 1 :00:0.30 to
1 :00:3:00, 1 .00 : 0.40 to 1 .00 : 2.50, or 1 .00 : 0.50 to 1 .00 : 2.00. The colloidally stable amphiphilic abrasive particles according to any one of claims 1 -8, wherein the surface of each of the colloidally stable amphiphilic abrasive particles is a covalently bonded polymeric crosslinked shell. . The colloidally stable amphiphilic abrasive particles according to any one of claims 1 -9, wherein the surface of each of the colloidally stable amphiphilic abrasive particles is a covalently bonded polyorganosiloxane crosslinked shell. . A method of making colloidally stable amphiphilic abrasive particles comprising: a. providing base abrasive particles having reactive M-OH groups on their surfaces and the base abrasive particles are dispersed in a solvent; b. modifying the surfaces of the base abrasive particles with a first step surface modifier having at least one hydrophilic group and at least one first reactive group capable to form a covalent bond with the reactive M- OH groups to obtain one-step modified abrasive particles; c. modifying surface of the one-step modified abrasive particles with a second step surface modifier having at least one hydrophobic group and having at least one second reactive group capable to form a covalent bond with reactive X-OH groups on surfaces of the one-step modified abrasive particles to obtain the amphiphilic abrasive particles; wherein the M in the reactive M-OH groups is selected from the group consisting of Si, Ce, Al, Zr, hybrids and/or mixtures thereof;
- 31 -
SUBSTITUTE SHEET (RULE 26) the X in the reactive X-OH groups is selected from the group consisting of Si, Ce, Al, Zr, C, P, N, hybrids and/or mixtures thereof; and the solvent is selected from the group consisting of water, alcohol preferably ethanol, ketone, ester, ether, glycol, and combinations thereof; preferably combinations of water and alcohol. The method of making colloidally stable amphiphilic abrasive particles according to claim 11 , wherein the at least one first reactive group or the at least one second reactive group is independently selected from the group consisting of si- alkoxides, si-halogenides (chlorides preferred), oximates, acetates, si-hydroxides; and combinations thereof; preferably siliciummethoxides and siliciumethoxides. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -12, wherein the first step surface modifier is selected from silanes having the at least one hydrophilic group and the second step surface modifier is selected from silanes having the at least one hydrophobic group. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -13, wherein the at least one hydrophilic group comprises at least one selected from the group comprising a N-containing group selected from the group comprising amines and substituted amines; amino group; ammonium; ammonium group and substituted ammonium group which includes but is limited to alkylammonium group comprising alkyl having < 20 C atoms, < 10 C atoms or < 4 C atoms; sulfonium; phosphonium; sulfate; sulfonate; phosphate; hydroxy; epoxy; carboxy; ether; polyether; or polyether groups; preferably a N- containing group selected from the group comprising amine, amino group, ammonium, and alkylammonium group. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -14, wherein the at least one hydrophilic group comprises at least one selected from the group consisting of amine, ammonium, and alkylammonium group comprising alkyl having < 20 C atoms; < 10 C atoms or < 4 C atoms.
- 32 -
SUBSTITUTE SHEET (RULE 26) The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -15, wherein the at least one hydrophobic group comprises at least one selected from the group consisting of alky group having < 20 C atoms, < 10 C atoms, or < 4 C atoms; and aryl has < 20 C atoms, < 10 C atoms, or < 8 C atoms. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -16, wherein the at least one hydrophobic group consisting of at least one selected from the group consisting of methyl, ethyl, propyl, butyl, phenyl, benzyl, tolyl, and xylyl. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -17, wherein the second step surface modifier comprises silanes having at least two, preferably at least three hydrophobic groups comprising alkyl with < 20 C atoms, < 10 C atoms or < 4 C atoms; or aryl with < 20 C atoms, < 10 C atoms, or < 8 C atoms. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -18, wherein the second step surface modifier does not carry a functional group on the hydrophobic group of alkyl- or aryl group. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -19, wherein the solvent is selected from the group consisting of water, ethanol, acetone, diethylether, propylenglycoldimethylether, propylenglycolmonoacetylester, isopropanol, n-propanol, propylenglycolmonomethylether, and combinations thereof; preferably combinations of water and ethanol. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -20, wherein total amount of the first step surface modifiers and the second step surface modifiers ranges from 0.01 -1 .0 mmol/g (mass of abrasives calculated as dry matter), 0.025-0.8 mmol/g, 0.05 - 0.5 mmol/g, or 0.1 - 0.4 mmol/g. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -21 , wherein the base abrasive particle is selected from
- 33 -
SUBSTITUTE SHEET (RULE 26) the group consisting of colloidal silica, fumed silica, alumina, ceria, and combinations thereof. The method of making colloidally stable amphiphilic abrasive particles according to any one of claim 11-22, wherein the first step surface modifiers is selected from the group consisting of amino-polyether silanes, and betain-type silanes. The method of making colloidally stable amphiphilic abrasive particles according to any one of claim 11-23, wherein the first step surface modifiers is selected from the group consisting of 3-aminopropyl- derivatives of ethoxy- or methoxysilanes; and combinations thereof. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -24, wherein the first step surface modifier is 3- aminopropylmethyldimethoxysilane. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -25, wherein the first step surface modifier is capable to react among themselves to form a covalently bonded polymeric crosslinked shell around the base abrasive particle. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -26, wherein the second step surface modifier is selected from the group consisting of trimethylmethoxysilane, trimethylethoxysilane, dimethylphenylmethoxysilane, diphenylsilanediol, diphenyldimethoxysilane, methylphenyldimethoxysilane, dimethyldimethoxysilane, hexamethyldisilazane, hexamethyldisiloxane, dimethylethylmethoxysilane, dimethyloctylmethoxysilane, dimethyloctadecylchlorosilane, dimethylhexadecylmethoxysilane, dimethyl(methylphenyl)methoxysilane, potassium-trimethylsilanoate, triethylmethoxysilane, and combinations thereof. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -27, wherein the second step surface modifier is selected
- 34 -
SUBSTITUTE SHEET (RULE 26) from the group consisting of trimethylmethoxysilane, trimethylethoxysilane, and combinations thereof. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -28, wherein the first step surface modifiers is 3- aminopropylmethyldimethoxysilane; and the second step surface modifier is selected from the group consisting of trimethylmethoxysilane, trimethylethoxysilane, and combinations thereof. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -29, wherein a ratio of the first step modifier and the reactant is in a range of 9.9 : 1 to 0.1 : 9.9, preferably 9:1 to 1 :9. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -30, wherein the first step surface modifiers can be used in combination with a reactant selected from the group consisting of tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, and combinations thereof; and ratio of the first step modifier and the reactant ranges from 9.9 : 1 to 0.1 : 9.9; preferably 9:1 to 1 :9. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 -31 further comprises step d after step c: keeping water as only dispersion after the second step surface modification. Colloidally stable amphiphilic abrasive particles made according to any one of claims 11 to 32. A chemical mechanical polishing(CMP) composition comprises: colloidally stable amphiphilic abrasive particles according to any one of claims 1 to 10 or claim 33; and solvent; optionally comprise at least one of: organic and inorganic salt as colloidal stabilizer; catalyst including but is not limited to fluoride ions, metal salts or metal alkoxides like titaniumisopropoxide; acid/base pH buffer agent;
- 35 -
SUBSTITUTE SHEET (RULE 26) biocide; oxidizer; catalyst; and corrosion inhibitor; wherein the solvent is selected from the group consisting of water; water soluble solvent selected from the group consisting of alcohol, ether, and ketone; and combinations thereof; and the CMP composition has a pH of 2 to 10, 2 to 8, 2 to 6, 2 to 5, 2 to 4, or 2 to 3. A chemical mechanical polishing (CMP) method comprises: providing a substrate having at least one surface comprising tungsten; providing a chemical mechanical polishing(CMP) composition comprises: colloidally stable amphiphilic abrasive particles according to any one of claims
1 to 10 or claim 33; and water-soluble solvent; wherein the CMP composition has a pH of 2 to 10, 2 to 8, 2 to 6, 2 to 5, 2 to 4, or 2 to 3; contacting the surface of the semiconductor substrate with the polishing pad and the chemical mechanical polishing composition; and polishing the least one surface comprising tungsten. The chemical mechanical polishing (CMP) method of claim 35, wherein the surface of the semiconductor substrate further comprises silicon dioxide film; and removal selectivity of W: SiC>2 is greater than 80, 100, 150, or 200. A chemical mechanical polishing (CMP) system comprises: a polishing pad; a substrate having at least one surface comprising tungsten; a chemical mechanical polishing(CMP) composition comprises: colloidally stable amphiphilic abrasive particles according to any one of claims 1 to 10 or claim 33; and water-soluble solvent;
- 36 -
SUBSTITUTE SHEET (RULE 26) wherein the CMP composition has a pH of 2 to 10, 2 to 8, 2 to 6, 2 to 5, 2 to 4, or 2 to 3; wherein the surface of the semiconductor substrate with the polishing pad and the chemical mechanical polishing composition so the tungsten can be polished. The chemical mechanical polishing (CMP) system of claim 37, wherein the surface of the semiconductor substrate further comprises silicon dioxide film; and removal selectivity of W: SiO2 is greater than 80, 100, 150, or 200.
- 37 -
SUBSTITUTE SHEET (RULE 26)
EP23904305.2A 2022-12-15 2023-12-05 Amphiphilic abrasive particles and their use for chemical mechanical planarization Pending EP4634324A1 (en)

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