TWI565770B - Aqueous polishing composition and process for chemically mechanically polishing substrates having patterned of unpatterned low-k dielectric layers - Google Patents

Description

Aqueous abrasive composition and method for chemical mechanical polishing of a substrate having a patterned or unpatterned low-k dielectric layer

The present invention is directed to a novel aqueous abrasive composition that is particularly useful for milling substrates having a patterned or unpatterned low k or ultra low k dielectric layer.

Furthermore, the present invention relates to a novel method for chemical mechanical polishing of substrates having patterned or unpatterned low k or ultra low k dielectric layers.

Cited document

The documents cited in the present application are hereby incorporated by reference in their entirety.

Chemical mechanical planarization or polishing (CMP) is the primary method for achieving local and complete flatness of integrated circuit (IC) devices. This technique typically applies a CMP composition or slurry containing an abrasive and other additives as an active chemical between the surface of the rotating substrate and the polishing pad under application of a load. Thus, CMP methods combine physical methods such as milling with chemical methods such as oxidation or chelation. The removal or grinding of the substrate material should not include only physical effects or only chemical effects, but should include a synergistic combination of the two to achieve rapid and uniform removal.

Thus, the substrate material is removed until the desired flatness or barrier sublayer or termination layer exposure is achieved. A flat, defect-free surface is ultimately obtained that allows for the fabrication of suitable multilayer IC devices by subsequent photolithography, patterning, etching, and thin film processing.

The gradual reduction in the feature size of circuit components in an integrated circuit (IC) device having a large-scale integration (LSI) or a very large-scale integration (VLSI) is improved The need to completely planarize the various surface layers of the IC by CMP. Typically, CMP involves removing a film such as the following:

- copper for conductive wiring,

- used as a diffusion barrier to prevent copper from diffusing into tantalum nitride, tantalum/niobium nitride or titanium in the dielectric material, and

- Cerium oxide used as an insulating dielectric material for the conductive wiring.

It is therefore necessary to be able to grind the different layers at the desired rate to obtain the desired defect-free surface, as described, for example, in US Patent Application No. US 2005/0076578 A1 (US Pat. No. 7,153, 335 B2) and US 2009/0311864 A1. Therefore, typical CMP slurries for barrier CMP require different components to increase and suppress the removal rate (MRR) to achieve the desired selectivity requirements.

Thus, the tantalum nitride MRR can be adjusted by an oxidizing agent such as hydrogen peroxide and a tantalum nitride enhancer such as malonic acid, which is a film-forming agent that interrupts the formation of yttria.

The MRR of cerium oxide (especially TEOS) can be inhibited by a polyol selectively adsorbed on a hydroxyl-rich surface.

The MRR of copper can be adjusted by using a combination of an enhancer such as L-histamine and a passivating agent such as benzotriazole (BTA).

In the semiconductor industry, CMP slurries for inter-metal dielectric layers based on germanium are particularly well developed and the chemical and mechanical properties of the rubbing and polishing of germanium-based dielectrics are well understood. However, a problem with germanium-based dielectric materials is that their dielectric constant is relatively high, and is determined to be about 3.9 or more depending on factors such as residual moisture content. Therefore, the capacitance between the conductive layers is also relatively high, which in turn limits the speed or frequency at which the IC can operate. The strategies developed to reduce capacitance include (1) incorporating metals with lower resistivity values (such as copper), and (2) using insulating materials with lower dielectric constant than cerium oxide (ie, low k and ultra low). k dielectric material) provides electrical insulation.

The low-k and ultra-low-k dielectric materials include organic polymeric materials, inorganic and organic porous dielectric materials, and blended or composite organic and inorganic materials, which may be porous or non-porous, such as carbon doped Cerium oxide material. It is highly desirable to incorporate such low k and ultra low k dielectric materials into the IC structure while still being able to polish the surface of the dielectric material using conventional CMP slurry during semiconductor wafer processing. In particular, it is highly desirable to achieve high selectivity for cerium oxide (especially TEOS) compared to low-k and ultra-low-k materials such as carbon-doped cerium oxide materials. This high selectivity is extremely important to maintain ultra-low k integrity, especially for 45 nm nodes and below 45 nm nodes and novel complementary metal oxide semiconductor (CMOS) generation.

US Patent Application No. US 2003/0228762 A1 discloses a CMP slurry for grinding a substrate containing a low-k dielectric layer, the CMP slurry containing:

Grinding particles selected from the group consisting of alumina, ceria, titania, yttria, zirconia, yttria, magnesia, and coformed products thereof;

An amphoteric nonionic surfactant having at least one hydrophobic head group and at least one hydrophilic tail group.

According to US 2003/0228762 A1, suitable head groups include polyoxyalkylene, tetra-C _1-4 alkyl decyne, saturated or partially unsaturated C _6-30 alkyl, polyoxypropylene groups, C _{6- 12} alkylphenyl or alkylcyclohexyl and polyethylene groups. Suitable tail groups include polyoxyethylene groups. Therefore, the amphoteric anionic surfactant may be selected from the group consisting of polyoxyethylene alkyl ethers or esters. However, according to the embodiment of US 2003/0228762 A1, the low-k dielectric MRR caused by the disclosed amphoteric nonionic surfactant is reduced by no more than 75%, and compared to low-k dielectric nitridation. The selectivity of ruthenium is not more than 3 for PETEOS compared to low-k dielectric.

European Patent Application EP 1 150 341 A1 discloses a CMP slurry for grinding a metal layer containing a nonionic polyoxyethylene-polyoxypropylene alkyl ether surfactant. However, the number of carbon atoms in the alkyl group and the distribution of the oxy-ethyl and oxy-propyl monomer units are not precisely defined. In addition, the European patent application remains silent on CMP low-k and ultra-low-k materials using CMP slurry containing such surfactants.

U.S. Patent Application No. US 2008/0124913 A1 discloses a CMP slurry containing a nonionic polyoxyethylene-polyoxypropylene alkyl ether surfactant of the formula:

CH ₃ -(CH ₂ ) _n -(CH(CH ₃ )CH ₂ O) _y (CH ₂ CH ₂ O) _x -

Wherein the subscript has the following meaning: n = 3-22, y = 1-30, and x = 1-30, wherein x + y is preferably at least 5, which is a polysilicon inhibitor.

U.S. Patent 6,645,051 B2 discloses a CMP slurry for polishing a memory hard disk substrate comprising a polyoxyethylene-polyoxypropylene alkyl ether surfactant. However, the number of carbon atoms in the alkyl group and the distribution of the oxy-ethyl and oxy-propyl monomer units are not precisely defined. In addition, U.S. patents remain silent on CMP low-k and ultra-low-k materials using CMP slurry containing such surfactants.

Purpose of the invention

It is an object of the present invention to provide a novel aqueous abrasive composition, particularly a CMP slurry, which is highly suitable for chemical mechanical polishing of patterned or unpatterned low k or ultra low k media having a dielectric constant of 3.5 or less. A substrate of an electrical layer, especially a semiconductor wafer.

More specifically, the novel aqueous abrasive composition should be highly suitable for barrier CMP of substrate materials other than the low-k and ultra-low-k dielectric layers, such as metal layers, barrier layers, and hafnium oxide layers.

Novel aqueous abrasive compositions, especially novel CMP slurries, should preferably remove the ruthenium dioxide layer and maintain the integrity of the low-k and ultra-low-k materials, ie, in terms of MRR compared to low-k and ultra-low-k materials. It has a particularly high selectivity for cerium oxide. The novel CMP slurry preferably does not affect the MRR of the metal layer and the barrier layer (when present). In particular, when the metal layer, the barrier layer, and the ceria layer are present in the substrate to be polished, the novel aqueous abrasive composition should exhibit as many combinations as possible of: (a) a high MRR of the metal layer, (b) High MRR of the barrier layer, (c) high MRR of cerium oxide, (d) high selectivity to cerium oxide in terms of MRR compared to low-k and ultra-low-k materials, (e) compared to low-k And the ultra-low-k material has high selectivity to the metal layer in terms of MRR and (f) high selectivity to the barrier layer in terms of MRR compared to the low-k and ultra-low-k materials. More specifically, when a copper layer, a tantalum nitride layer, and a hafnium oxide layer are present in a substrate to be polished, the novel aqueous abrasive composition should exhibit as many combinations of the following characteristics: (a') high MRR of copper , (b') high MRR of tantalum nitride, high MRR of (c') cerium oxide, (d') is highly selective for cerium oxide in terms of MRR compared to low-k and ultra-low-k materials, E') is highly selective for copper in terms of MRR compared to low-k and ultra-low-k materials and (f') is highly selective for tantalum nitride in MRR compared to low-k and ultra-low-k materials.

In addition, it is an object of the present invention to provide a novel method for chemical mechanical polishing of substrates, particularly semiconductor wafers, having a patterned and unpatterned low k or ultra low k dielectric layer having a dielectric constant of 3.5 or less. .

More specifically, the novel method should be well suited for barrier CMP of substrate materials other than low-k and ultra-low-k dielectric layers that exist in other materials, such as metal layers, barrier layers, and hafnium oxide layers.

The novel method should preferably remove the ruthenium dioxide layer and maintain the integrity of the low-k and ultra-low-k materials, that is, it should be particularly high in terms of MRR for cerium oxide compared to low-k and ultra-low-k materials. Selectivity. Preferably, the novel method should not affect the MRR of the metal layer and the barrier layer (when present).

Thus, a novel aqueous abrasive composition comprising: (A) at least one abrasive particle, and (B) at least one amphoteric nonionic surfactant selected from the group consisting of water-soluble or water-dispersible interfacial activity having the following properties was discovered a group consisting of: (b1) at least one hydrophobic group selected from the group consisting of branched alkyl groups having 5 to 20 carbon atoms; and (b2) at least one hydrophilic group selected from a group comprising the following polyoxyalkylene groups: (b21) an oxy-ethyl monomer unit, and (b22) at least one substituted oxyalkylene monomer unit, wherein The substituent is selected from the group consisting of alkyl, cycloalkyl or aryl, alkyl-cycloalkyl, alkyl-aryl, cycloalkyl-aryl and alkyl-cycloalkyl-aryl; The polyoxyalkylene group contains monomer units (b21) and (b22) which are randomly distributed, alternately distributed, gradient-distributed, and/or block-likely distributed.

Hereinafter, the novel aqueous polishing composition is referred to as "the composition of the present invention".

In addition, a novel method of chemical mechanical polishing of a patterned or unpatterned low-k dielectric or ultra-low-k substrate having a dielectric constant of 3.5 or less was found, the method comprising the steps of: (1) The substrate material is contacted at least once with the aqueous abrasive composition comprising: (A) at least one abrasive particle, and (Ba) at least one amphoteric nonionic surfactant selected from the group consisting of water-soluble or water-dispersible interfacial activity having the following a group consisting of: (b1a) at least one hydrophobic group selected from the group consisting of a linear alkyl group having 5 to 20 carbon atoms and a branched alkyl group (b1); and (b2) at least one a hydrophilic group selected from the group consisting of polyoxyalkylene groups of the following: (b21) oxyethylidene monomer units, and (b22) at least one substituted oxyalkylene monomer unit, wherein The substituent is selected from the group consisting of alkyl, cycloalkyl or aryl, alkyl-cycloalkyl, alkyl-aryl, cycloalkyl-aryl and alkyl-cycloalkyl-aryl; The polyoxyalkylene group has a random distribution, an alternating distribution, a gradient distribution, and/or a block-like Monomer unit (B21) and the cloth (B22); (2) chemically mechanically polishing the substrate at a certain temperature for a certain period of time until the desired complete flatness is achieved; and (3) removing the substrate from contact with the aqueous abrasive composition of the present invention.

In the following, a novel method of chemically and mechanically polishing a substrate having a patterned and unpatterned low-k and ultra-low-k dielectric layer having a dielectric constant of 3.5 or less is referred to as "the method of the present invention".

Last but not least, the novel compositions of the compositions of the invention have been found to be useful in the manufacture of electrical, mechanical and optical devices, hereinafter referred to as "the use of the invention".

Advantages of the invention

In view of the prior art, it has been surprisingly discovered and appreciated by those skilled in the art that the objects of the present invention can be solved by the compositions, methods, and uses of the present invention.

It has been particularly surprisingly found that the compositions of the present invention are highly suitable for chemical mechanical polishing of substrates, particularly semiconductor wafers, having a patterned or unpatterned low k or ultra low k dielectric layer having a dielectric constant of 3.5 or less.

It has been particularly surprisingly found that the compositions of the present invention are highly suitable for barrier CMP of substrate materials in which other materials, such as metal layers, barrier layers, and ruthenium dioxide layers, exist in addition to the low-k and ultra-low-k dielectric layers.

It has been surprisingly found that the compositions of the present invention are also highly suitable for use in the present invention, i.e., in the manufacture of electrical, mechanical, and optical devices in which high precision grinding steps are required.

In the method of the present invention, the composition of the present invention preferably removes the ruthenium dioxide layer and maintains the integrity of the low-k and ultra-low-k layers, that is, compared to the low-k and An ultra-low k material which has a particularly high selectivity for cerium oxide in terms of MRR. The composition of the present invention preferably does not affect the MRR of the metal layer and the barrier layer (when present).

Moreover, the method of the present invention is most suitable for chemical mechanical polishing of substrates, particularly semiconductor wafers, having a patterned or unpatterned low k or ultra low k dielectric layer having a dielectric constant of 3.5 or less.

More specifically, the method of the present invention is most suitable for barrier CMP of substrates other than low-k and ultra-low-k dielectric layers, such as metal layers, barrier layers, and hafnium oxide layers.

The method of the present invention preferably removes the cerium oxide layer and maintains the integrity of the low-k and ultra-low-k materials, that is, it has a particularly high selectivity for cerium oxide in terms of MRR compared to low-k and ultra-low-k materials. Sex. The composition of the present invention preferably does not affect the MRR of the metal layer and the barrier layer (when present).

The composition of the present invention is an aqueous composition. This means that it contains water, especially ultrapure water, as the main solvent and dispersant. However, the composition of the present invention may contain at least one water-miscible organic solvent, but only in a small amount so as not to change the aqueous properties of the composition of the present invention.

The composition of the present invention preferably contains water in an amount of from 60 to 99.95% by weight, more preferably from 70 to 99.9% by weight, even more preferably from 80 to 99.9% by weight and most preferably from 90 to 99.9% by weight, based on the composition of the present invention. Total weight.

By "water soluble" is meant that at the molecular level, the relevant components or ingredients of the compositions of the invention are soluble in the aqueous phase.

By "water dispersibility" is meant that the relevant components or ingredients of the compositions of the present invention can be dispersed in the aqueous phase and form a stable emulsion or suspension.

"Oligomer" or "oligomerization" means that the composition of the present invention and the relevant component of the alkylene oxide of the surfactant (B) group are composed of 3 to 10 bonded monomer structural units.

"Polymer" or "polymeric" means that the composition of the present invention and the relevant component of the alkylene oxide group of the surfactant (B) are composed of more than 10 bonded monomer structural units.

The first main component of the composition of the present invention is at least one, preferably one, abrasive particle (A).

The average particle size of the abrasive particles (A) can vary widely, and thus can be most advantageously adjusted in accordance with the specific requirements of the established compositions and methods of the present invention. The average particle diameter is preferably in the range of 1 to 2000 nm, preferably in the range of 1 to 1000 nm, more preferably in the range of 1 to 750 nm, and most preferably in the range of 1 to 500 nm, as measured by dynamic laser light scattering. Within the scope. The primary particles can also aggregate to form secondary aggregates.

The particle size distribution of the abrasive particles (A) may be monomodal, bimodal or multimodal. The particle size distribution is preferably unimodal so that the abrasive particles (A) have characteristics that are easy to reproduce properties and that easy reproduction conditions are obtained during the method of the present invention.

Further, the particle size distribution of the abrasive particles (A) may be narrow or broad. The particle size distribution is preferably narrow, having only a small amount of small particles and large particles, so that the abrasive particles (A) have characteristics of easy reproduction properties and easy reproduction conditions are obtained during the method of the present invention.

The abrasive particles (A) may have various shapes. Thus, it can have one or substantially one shape. However, the abrasive particles (A) may also have different shapes. In particular, two differently shaped abrasive particles (A) may be present in the intended compositions of the invention. Regarding its own shape, it may be a cube, a chamfered cube, an octahedron, an icosahedron, an irregular sphere, and a sphere with or without protrusions or depressions. The shape is preferably a sphere with no or only a few protrusions or depressions. This shape is generally preferred because it generally increases the resistance to mechanical forces experienced by the abrasive particles (A) during the CMP process.

In principle, any type of abrasive particles (A) can be used for the composition of the present invention as long as it has the above characteristics. Therefore, the abrasive particles (A) may be organic or inorganic particles or organic-inorganic hybrid particles. The abrasive particles (A) are preferably inorganic particles.

The inorganic abrasive particles (A) are more preferably selected from the group consisting of alumina, ceria, titania, cerium oxide, zirconium oxide, cerium oxide, magnesium oxide, coformed products thereof, and mixtures thereof. Cerium oxide is preferably used as the abrasive particles (A).

The amount of abrasive particles (A) used in the compositions of the present invention can vary widely and, therefore, can be most advantageously adjusted in accordance with the particular requirements of the established compositions and methods of the present invention. The composition of the present invention preferably contains 0.005 to 10% by weight, more preferably 0.01 to 8% by weight and most preferably 0.01 to 6% by weight of the abrasive particles (A), based on the total weight of the composition of the present invention.

The second main component of the composition of the present invention is at least one, preferably a water-soluble or water-dispersible, preferably water-soluble amphoteric nonionic surfactant (B).

The amphoteric nonionic surfactant (B) comprises at least one hydrophobic group (b1). This means that the amphoteric nonionic surfactant (B) may have more than one hydrophobic group (b1), for example 2, 3 or more groups (b1), which consist of at least one of the following hydrophilic groups Groups (b2) are separated from each other.

The hydrophobic group (b1) is selected from the group consisting of branched alkyl groups having 5 to 20, preferably 7 to 16, and most preferably 8 to 15 carbon atoms.

Preferably, the branched alkyl group (b1) has an average degree of branching of from 1 to 5, preferably from 1 to 4 and most preferably from 1 to 3.

Suitable branched alkyl groups (b1) are derived from isopentane, neopentane and branched hexane, heptane, octane, decane, decane, undecane, dodecane, tridecane, tetradecane , pentadecane, hexadecane, heptadecane, nonadecane and eicosane isomers.

The amphoteric nonionic surfactant (B) contains at least one hydrophilic group (b2). This means that the amphoteric nonionic surfactant (B) contains more than one group (b2), for example 2, 3 or more groups (b2), which are separated from each other by a hydrophobic group (b1).

Therefore, the amphoteric nonionic surfactant (B) may have a different block-like structure. Examples of such block-like structures are:

-b1-b2,

-b1-b2-b1,

-b2-b1-b2,

-b2-b1-b2-b1,

-b1-b2-b1-b2-b1, and

-b2-b1-b2-b1-b2.

The hydrophilic group (b2) is selected from the group consisting of polyoxyalkylene groups which may be oligomeric or polymeric groups.

The hydrophilic group (b2) contains an oxyethyl monomer unit (b21).

Further, the hydrophilic group (b2) comprises at least one substituted oxyalkylene monomer unit (b22) wherein the substituent is selected from the group consisting of an alkyl group, a cycloalkyl group and an aryl group.

The oxyalkylene monomer unit (b22) is preferably derived from a substituted ethylene oxide wherein the substituent is selected from the group consisting of an alkyl group, a cycloalkyl group, and an aryl group.

The substituent itself may also carry an inert substituent, that is, a substituent which does not adversely affect the copolymerization of ethylene oxide and the surface activity of the amphoteric nonionic surfactant (B). Examples of such inert substituents are fluorine and chlorine atoms, nitro groups and nitrile groups. In the case of substitution it is used in an amount which does not adversely affect the hydrophilicity-hydrophobic balance of the surfactant (type B). Substituents are preferably free of such inert substituents.

The substituent of the ethylene oxide is preferably selected from the group consisting of an alkyl group having 1 to 10 carbon atoms; and having 5 to 10 carbon atoms in the spiro ring, the outer ring and/or the annealed configuration. a cycloalkyl group; an aryl group having 6 to 10 carbon atoms; an alkyl-cycloalkyl group having 6 to 20 carbon atoms; an alkyl-aryl group having 7 to 20 carbon atoms; having 11 to 20 a cycloalkyl-aryl group of a carbon atom; and an alkyl-cycloalkyl-aryl group having 12 to 30 carbon atoms.

Examples of suitable alkyl groups are methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, t-butyl, n-pentyl, 2- and 3-methylpentyl, 2,2 - dimethylpropyl, n-hexyl, 2-, 3- and 4-methylpentyl, 2,2- and 3,3-dimethylbutyl, n-heptyl, 2,3-dimethylpentyl Base, 2,3,3-trimethylbutyl, n-octyl, isooctyl, 2-ethylhexyl, n-decyl, 2-ethyl-3,4-dimethylpentyl and n-decyl Preferred are methyl, ethyl, propyl, isopropyl, n-butyl, n-pentyl and n-hexyl.

Examples of suitable cycloalkyl groups are cyclopentyl, cyclohexyl, cyclopentane-1,1-diyl, cyclopentane-1,2-diyl, cyclohexane-1,1-diyl and cyclohexane. -1,2-diyl.

Examples of suitable aryl groups are phenyl and 1- and 2-naphthyl.

Examples of suitable alkyl-cycloalkyl groups are cyclopentyl- and cyclohexylmethyl, 2-cyclopentyl- and 2-cyclohexyleth-1-yl, 3-cyclopentyl- and 3-cyclohexylpropane- 1-yl, and 4-cyclopentyl- and 4-cyclohexyl-n-but-1-yl.

Examples of suitable alkyl-aryl groups are phenylmethyl, 2-phenyleth-1-yl, 3-phenylprop-1-yl and 4-phenyl-n-butan-1-yl.

Examples of suitable cycloalkyl-aryl groups are 4-phenyl-cyclohex-1-yl, 4-cyclohexyl-phenyl-1-yl and 2,3-dihydroindole-1,2-diyl.

Examples of suitable alkyl-cycloalkyl-aryl groups are cyclohexyl-phenyl-methyl and 2-cyclohexyl-2-phenyl-eth-1-yl.

Examples of particularly preferred substituted ethylene oxides are methyl, ethyl, 2,2- and 2,3-dimethyl, 2,2,3-trimethyl, 2,2,3,3- Tetramethyl, 2-methyl-3-ethyl, 2,2 and 2,3-diethyl, n-propyl, 2-methyl-3-n-propyl, n-butyl, n-pentyl, hexyl , n-heptyl, n-octyl, n-decyl, n-decyl, cyclopentyl, cyclohexyl, phenyl and naphthyl oxirane; 1,2-epoxy-cyclohexane and cyclopentane Alkane; 1-oxa-3-spiro[3.4]-heptane, 1-oxa-3-spiro[3.5]-octane; and 1,2-epoxy-2,3-dihydroindole.

Methyloxirane (propylene oxide) and ethyloxirane (butylene oxide) are particularly preferably used.

The hydrophilic group (b2) is preferably composed of monomer units (b21) and (b22).

The polyoxyalkylene group contains monomer units (b21) and (b22) which are randomly distributed, alternately distributed, gradient-distributed, and/or block-likely distributed. This means that a hydrophilic group (b2) can have only one distribution, ie

- Random: ...-b21-b21-b22-b21-b22-b22-b22-b21-b22-...;

- Alternate: ...-b21-b22-b21-b22-b21-....;

- gradient: ... b21-b21-b21-b22-b21-b21-b22-b22-b21-b22-b22-b22-...; or

- Block-like: ...-b21-b21-b21-b21-b22-b22-b22-b22-....

Alternatively, the hydrophilic group (b2) may contain at least two distributions, such as oligomeric or polymeric segments with random distribution and oligomeric or polymeric segments with alternating distribution.

The hydrophilic group (b2) preferably has only one distribution. The distribution is best as random or block-like distribution.

The molar ratio of the oxyethyl monomer unit (b21) to the oxyalkylene monomer unit (b22) can vary widely and can therefore be most advantageously adjusted in accordance with the particular requirements of the compositions, methods and uses of the present invention. Mohr ratio (b21): (b22) is preferably from 100:1 to 1:1, more preferably from 60:1 to 1.5:1 and most preferably from 50:1 to 1.5:1.

The degree of polymerization of the oligomeric and polymeric polyoxyalkylene groups (b2) can also vary widely, and thus can be most advantageously adjusted in accordance with the particular requirements of the compositions, methods and uses of the present invention. The degree of polymerization is preferably in the range of 5 to 100, preferably in the range of 5 to 90 and most preferably in the range of 5 to 80.

Amphiphilic nonionic surfactant (B) is conventional and known material and commercially available under the trademark Plurafac ^TM from BASF SE.

The concentration of the amphoteric nonionic surfactant (B) in the composition of the present invention can vary widely, and thus can be most advantageously adjusted in accordance with the specific requirements of the compositions, methods and uses of the present invention. The concentration is preferably in the range of 1 ppm to 0.1% by weight, more preferably in the range of 10 ppm to 0.09% by weight, even more preferably in the range of 100 ppm to 0.08% by weight, and most preferably in the range of 200 ppm to 0.08% by weight. The weight specifications are based on the total weight of the composition of the invention.

The composition of the present invention may additionally contain at least one functional component (C) different from the components (A) and (B). It is preferred to use at least two functional components (C).

The functional component (C) is more preferably selected from the group consisting of: an amphoteric nonionic surfactant other than the surfactant (B), a polyol having at least two hydroxyl groups, a minimum critical solution temperature LCST or High critical solution temperature UCST substance, oxidant, passivating agent, charge reversal agent, complexing agent or chelating agent, friction suppressing agent, stabilizer, pH adjuster, cerium nitride enhancer, buffer, rheological agent , surfactants, metal cations and organic solvents.

Examples of suitable amphoteric nonionic surfactants (C) are described, for example, in paragraphs [0013] to 4 [0023] of page 3 of European Patent EP 1 534 795 B1.

Suitable polyols (C) are diols such as ethylene glycol and propylene glycol; triols such as glycerol; pentaerythritol, alditol, cyclic alcohol, and glycerol, trimethylolpropane, pentaerythritol, alditol and cyclic alcohol Dimers and oligomers.

Suitable oxidizing agents (C) and their effective amounts are described, for example, in European Patent Application EP 1 036 836 A1, page 8, paragraphs [0074] and [0075] or US Patent 6,068,787, column 4, line 40 to column 7. Line 45, lines 18 to 34 of line 45 or US 7,300,601 B2 are known. It is preferred to use organic and inorganic peroxides, and it is more preferred to use inorganic peroxides. Hydrogen peroxide can be used in particular.

Suitable for passivating agent (C) (which is also known as a corrosion inhibitor) and its effective amount is, for example, US Pat. No. 7,300,601 B2, col. 3, line 59 to col. 4, line 9, US Patent Application US 2008/0254628 A1 It is known from paragraph 4 [0058] of page 4 and page 5 or paragraph [0031] of page 5 of European Patent EP 1 534 795 B1.

Suitable as a binder or chelating agent (C) (which is sometimes also referred to as a friction reducing agent (see US Patent Application No. US 2008/0254628 A1, page 5, paragraph [0061]) or an etchant (see US Patent Application US 2008) 0254628 A1, page 4, paragraph [0054]) and its effective amount are known, for example, from US Pat. No. 7,300,601 B2, column 4, lines 35 to 48, or European patent EP 1 534 795 B1, page 5, paragraph [0029]. It is especially preferred to use an amino acid (especially glycine and L-histamine) and a carboxylic acid (such as malonic acid).

Suitable stabilizers (C) and their effective amounts are known, for example, from U.S. Patent No. 6,068,787, at col. 8, lines 4 to 56.

Suitable pH adjusters and buffers (C) and their effective amounts are, for example, from European Patent Application EP 1 036 836 A1, page 8, paragraph [0080], paragraphs [0085] and [0086]; international patent applications WO 2005/014753 A1, page 12, lines 19 to 24; U.S. Patent Application No. US 2008/0254628 A1, page 6, paragraph [0073] or U.S. Patent 7,300,601 B2, column 5, lines 33 to 63, is known.

Suitable for the cerium nitride enhancer (C) are low molecular weight carboxylic acids such as acetic acid, oxalic acid and malonic acid, especially malonic acid.

Suitable rheological agents (C) and their effective amounts are known, for example, from U.S. Patent Application No. US 2008/0254628 A1, page 5, paragraph [0065] to page 6, paragraph [0069].

Suitable surfactants (C) and their effective amounts are, for example, from International Patent Application No. WO 2005/014753 A1, page 8, line 23 to page 10, line 17, or US Patent 7,300,601 B2, column 5, line 4 to item 6. Line 8 of the column is known.

Suitable polyvalent metal ions (C) and their effective amounts are known, for example, from European Patent Application EP 1 036 836 A1, page 8, paragraph [0076] to page 9, paragraph [0078].

Suitable organic solvents (C) and their effective amounts are known, for example, from U.S. Patent No. 7,361,603 B2, at col. 7, lines 32 to 48, or from U.S. Patent Application No. US 2008/0254628 A1, page 5, paragraph [0059].

Suitable materials (C) exhibiting a minimum critical solution temperature LCST or a maximum critical solution temperature UCST are described, for example, in H. Mori, H. Iwaya, A. Nagai and T. Endo, Controlled synthesis of thermoresponsive polymers derived from L-proline via RAFT polymerization. , Chemical Communication, 2005, 4872-4874; or D. Schmaljohann, Thermo-and pH-responsive polymers and drug delivery, Advanced Drug Delivery Reviews, Vol. 58 (2006), 1655-1670; or US Patent Application US 2002/0198328 A1, US 2004/0209095 A1, US 2004/0217009 A1, US 2006/0141254 A1, US 2007/0029198 A1, US 2007/0289875 A1, US 2008/0249210 A1, US 2008/0050435 A1 or US US Patent Nos. 5,057,560, 5,788,82 and 6,682,642 B2; International Patent Application WO 01/60926 A1, WO 2004/029160 A1, WO 2004/0521946 A1, WO 2006/093242 A2 or WO 2007/ 012763 A1; European Patent Application No. EP 0 583 814 A1, EP 1 197 587 B1 and EP 1 942 179 A1; or German Patent Application No. DE 26 10 705.

In principle, any known charge reversal agent (C) commonly used in the field of CMP can be used. The charge reversal agent (C) is preferably selected from the group consisting of monomers, oligomerization and polymerization containing at least one anionic group selected from the group consisting of carboxylate, sulfonate, sulfate and phosphonate groups. Compound.

Preferably, the pH of the composition of the present invention is preferably set between 8 and 12 using the above pH adjusting agent (C).

The preparation of the composition of the present invention does not exhibit any particularity, but can be carried out by dissolving or dispersing the above components (A) and (B) and optionally (C) in an aqueous medium, especially deionized water. For this purpose, conventional and standard mixing methods and mixing equipment such as a stirred vessel, an in-line dissolver, a high shear impeller, an ultrasonic mixer, a homogenizer nozzle or a countercurrent mixer can be used. . The composition of the invention thus obtained is preferably filtered through a filter of a suitable mesh size to remove coarse particles, such as agglomerates or aggregates of solid finely dispersed abrasive particles (A).

In accordance with the use of the present invention, the compositions of the present invention are highly suitable for the fabrication of electrical, mechanical and optical devices in which high precision grinding steps are required in the manufacturing process.

For example, the electrical device is an IC device, a liquid crystal panel, an organic electroluminescent panel, a printed circuit board, a micromachine, a DNA wafer, a micro factory, and a magnetic head; the mechanical device is a high precision mechanical device; and the optical device is an optical glass (such as Photomask, lens and ruthenium), inorganic conductive film (such as indium tin oxide (ITO)), optical integrated circuit, optical conversion element, optical waveguide, optical single crystal (such as end face of optical fiber and scintillator), solid ray A sapphire substrate that emits single crystal, blue laser, LED, a semiconductor single crystal, and a glass substrate of a magnetic disk.

IC devices, particularly LSI and VLSI IC devices, preferably contain structures having a size of less than 50 nm.

The compositions of the present invention are most suitable for the method of the present invention.

In the method of the present invention, a substrate having a patterned and unpatterned low-k dielectric layer having a dielectric constant of 3.5 or less, particularly a semiconductor wafer, more specifically a germanium or germanium alloy semiconductor wafer (such as a silicon wafer) contact with the aqueous abrasive composition containing at least one of the following:

(A) at least one of the abrasive particles described above, and

(Ba) at least one amphoteric nonionic surfactant selected from the group consisting of water soluble or water dispersible surfactants:

(b1a) at least one hydrophobic group selected from the group consisting of a linear alkyl group having 5 to 20 carbon atoms and a branched alkyl group (b1) as described above;

(b2) at least one hydrophilic group selected from the group consisting of the above polyoxyalkylene groups, the polyoxyalkylene groups comprising a random distribution, an alternating distribution, a gradient distribution, and/or a block-like distribution of oxygen extension Ethyl monomer unit (b21) and at least one substituted oxyalkylene monomer unit (b22).

With respect to the substrate having the patterned and unpatterned low-k dielectric layer used in the above method of the present invention, the low-k dielectric layer has a dielectric constant of 3.5 or less, preferably 3.3 or less. Most preferably 3.1 or less, most preferably 2.8 or less, for example 2.4 or less.

With respect to the substrate having the patterned and unpatterned low-k dielectric layer used in the above method of the present invention, the low-k dielectric layer preferably has a dielectric constant of at least 0.01, more preferably at least 0.1, most preferably. It is at least 0.3, for example at least 2.0.

Suitable linear alkyl groups (b1a) having 5 to 20 carbon atoms are derived from pentane, hexane, heptane, octane, decane, decane, undecane, dodecane, tridecane, fourteen Alkane, pentadecane, hexadecane, heptadecane, nonadecane and eicosane.

Thereafter, the substrate is chemically mechanically ground at a temperature for a certain period of time to sufficiently achieve the desired complete and partial flatness, and then the substrate is removed from contact with the aqueous abrasive composition.

The method of the present invention exhibits particular advantages when CMP semiconductor wafers having patterned layers consisting of low-k or ultra-low-k ytterbium oxide dielectric as an insulating layer, ruthenium dioxide hard mask layer, It is composed of tantalum nitride and conductive copper wire as a termination layer or a barrier layer.

Suitable methods for low-k or ultra-low-k dielectric materials and for preparing insulating dielectric layers are described in, for example, U.S. Patent Application No. US 2005/0176259 A1, page 2, paragraphs [0025] to [0027], US 2005/0014667 A1. 1 page [0003], US 2005/0266683 A1 page 1 page [0003] and page 2 page [0024] or US 2008/0280452 A1 paragraphs [0024] to [0026]; US patent US 7,250,391 B2, column 1, lines 49 to 54; European Patent Application EP 1 306 415 A2, page 4, paragraph [0031]; European Patent EP 1 534 795 B1, page 5, paragraph [0026].

Carbon doped cerium oxide (CDO) is best used as a low-k or ultra-low-k dielectric material. For example, using BlackDiamond ^TM (from Applied Materials, Inc.) as a low-k or ultra low-k dielectric material. BlackDiamond ^TM (from Applied Materials, Inc.) of a dielectric constant of about 3.0.

The method of the present invention is particularly suitable for barrier CMP processes that require selective removal of germanium dioxide without affecting the integrity of the low-k or ultra-low-k dielectric layer on the patterned semiconductor wafer. Therefore, in the method of the present invention, it is required to have high selectivity to cerium oxide in terms of MRR compared to low-k or ultra-low-k dielectric materials. The MRR of the tantalum nitride or tantalum/tantalum nitride layer and the copper layer (when present) is preferably unaffected.

A particular advantage of the method of the present invention is that it exhibits a selectivity of >3, preferably >5 in terms of MRR compared to a low-k or ultra-low-k dielectric material.

The method of the present invention does not exhibit particularities and can be carried out using methods and apparatus commonly used to fabricate CMP in semiconductor wafers with ICs.

As is known in the art, a typical apparatus for CMP consists of a rotating platen covered with a polishing pad. The wafer is mounted on a carrier or chuck with the upper side facing downward toward the polishing pad. The carrier secures the wafer to a horizontal position. This particular configuration of the grinding and holding device is also referred to as a hard plate design. The carrier may retain a carrier pad between the holding surface of the carrier and the surface on which the wafer is not intended to be ground. This pad can act as a cushion for the wafer.

Below the carrier, the larger diameter platen is also generally horizontally disposed and provides a surface that is parallel to the surface of the wafer to be polished. During the planarization process, the polishing pad contacts the wafer surface. During the CMP process of the present invention, the compositions of the present invention are applied to the polishing pad in a continuous stream or in a drop-wise manner.

The carrier and the platen are rotated about respective axes of rotation extending perpendicularly from the carrier and the platen. The rotating carrier shaft can be held in place relative to the rotating platen or can oscillate horizontally relative to the platen. The direction of rotation of the carrier is typically (but not necessarily) the same as the platen. The rotational speed of the carrier and the platen is substantially (but not necessarily) set to a different value.

Typically, the temperature of the platen is set to a temperature between 10 ° C and 70 ° C.

For further details, see International Patent Application No. WO 2004/063301 A1, in particular paragraph 16 [0036] to page 18 [0040], and Figure 1.

Via the method of the present invention, a semiconductor wafer having an IC comprising patterned low-k and ultra-low-k material layers, especially a carbon-doped cerium oxide layer, and having excellent flatness can be obtained. Therefore, a copper mosaic pattern which also has excellent flatness and excellent electrical function (in the completed IC) can be obtained.

Examples and comparative experiments

Examples 1 to 2 and comparative experiments C1 to C2

Preparation and grinding characteristics of CMP slurry 1 to 2 (Examples 1 to 2) and C1 to C2 (Comparative experiments C1 and C2)

The CMP slurries 1, 2, C1 and C2 were prepared by dissolving and dispersing their components in ultrapure water. The composition of the CMP slurry is compiled in Table 1.

Table 1: Composition of CMP Slurry 1 to 2 (Examples 1 to 2) and C1 to C2 (Comparative Experiments C1 and C2) ^a)

a) average primary particle diameter d1: 35 nm; average secondary particle diameter d2: 70 nm; aggregate ratio d2/d1: 2; (FUSO ^TM PL-3 from Fuso Chemical);

b) benzotriazole;

c) a nonionic polyoxyethylene-polyoxypropylene alkyl ether surfactant (from DOW) which is a mixture of molecules having an average of 8, 9, or 10 carbon atoms, and such as 1H-NMR The spectrum shows a linear alkyl polyoxyethylene-polyoxypropylene polymer;

d) A = nonionic polyoxyethylene-polyoxybutylene alkyl ether surfactant, which is a branched alkyl group having 9, 10 or 11 carbon atoms and 7 oxygens on an average block-like distribution a mixture of molecules of an ethylenic monomer unit and 1.5 oxybutylene monomer units;

e) B = nonionic polyoxyethylene-polyoxypropylene alkyl ether surfactant, which has an average of a randomly distributed branched alkyl group having 13, 14 or 15 carbon atoms and 16 oxy-ethyl groups a mixture of monomer units and molecules of four oxy-propyl monomer units;

4 kg of 31% by weight of hydrogen peroxide was added per 100 kg of each CMP slurry prior to grinding.

Chemically mechanically grind 200 mm blanket-type tantalum wafers with CMP Slurry 1, 2, C1 and C2 under the following conditions, these blanket-type tantalum wafers have 15,000 (1500 nm) initial thickness TEOS layer, 15,000 (1500 nm) initial thickness of copper layer or 2000 (200 nm) initial thickness of tantalum nitride layer or 10,000 (1000 nm) initial thickness of the ultra low-k carbon doped silicon dioxide of layer (Black Diamond ^TM BD1, Applied Materials Inc.):

- Grinding equipment: AMAT Mirra (rotary);

- platen speed: 130 rpm;

- carrier speed: 83 rpm;

- polishing pad: Fujibo;

- pad adjustment: on the spot (in my situ)

- slurry flow rate: 200 ml / min;

- Adjust the downforce: 5 lbf (22.24 N);

- Number of dummy wafers: 4;

- grinding down pressure: 3 psi (205 mbar);

- Buckle pressure: 3 psi (205 mbar);

- Inner tube pressure: 2.5 psi (171 mbar)

- Grinding time: 60 seconds.

The MRR is determined by weighing the wafer before and after grinding. The grinding results are compiled in Table 2.

From the results of Table 2, it is obvious that the selectivity to cerium oxide, cerium nitride and copper can be significantly improved compared to the ultra-low-k dielectric material, and the MRR of cerium oxide, tantalum nitride and copper is not adversely affected. . This conclusion can also be significantly reduced from the ultra low k dielectric material MRR from 586 (comparative experiment C1) to 94 (Example 2), ie, a reduction of about 84%. Therefore, the CMP slurries 1 to 2 of Examples 1 to 2 are suitable for the barrier CMP method.

Claims (15)

An aqueous abrasive composition comprising: (A) abrasive particles selected from the group consisting of cerium oxide, cerium oxide, and mixtures thereof, and (B) at least one amphoteric nonionic surfactant selected from the group consisting of a group of water-soluble or water-dispersible surfactants: (b1) at least one hydrophobic group selected from the group consisting of branched alkyl groups having 5 to 20 carbon atoms; and (b2) at least a hydrophilic group selected from the group consisting of polyoxyalkylene groups of the following: (b21) oxyethylidene monomer units, and (b22) at least one substituted oxyalkylene monomer unit, Wherein the substituent is selected from the group consisting of alkyl, cycloalkyl or aryl, alkyl-cycloalkyl, alkyl-aryl, cycloalkyl-aryl and alkyl-cycloalkyl-aryl The polyoxyalkylene group contains the monomer units (b21) and (b22) which are randomly distributed, alternately distributed, gradient-distributed, and/or block-likely distributed. The aqueous abrasive composition of claim 1, wherein the hydrophobic group (b1) is selected from the group consisting of branched alkyl groups having 8 to 15 carbon atoms. The aqueous abrasive composition of claim 1 or 2, wherein the oxyalkylene monomer unit (b22) is derived from a substituted ethylene oxide, wherein the substituent is selected from the group consisting of Group of: alkyl, cycloalkyl or aryl, alkyl-cycloalkyl, alkyl-aryl, cycloalkyl-aryl and Alkyl-cycloalkyl-aryl. The aqueous abrasive composition of claim 3, wherein the substituents are selected from the group consisting of alkyl groups having from 1 to 10 carbon atoms; spiro, extracyclic and/or cyclic configurations. a cycloalkyl group having 5 to 10 carbon atoms; an aryl group having 6 to 10 carbon atoms; an alkyl-cycloalkyl group having 6 to 20 carbon atoms; an alkyl group having 7 to 20 carbon atoms - An aryl group; a cycloalkyl-aryl group having 11 to 20 carbon atoms; and an alkyl-cycloalkyl-aryl group having 12 to 30 carbon atoms. An aqueous abrasive composition according to claim 4, characterized in that the molar ratio of the monomer unit (b21) to the monomer unit (b22) is from 100:1 to 1:1. The aqueous abrasive composition of claim 1 or 2, wherein the polyoxyalkylene group has a degree of polymerization of from 5 to 100. The aqueous abrasive composition according to claim 1 or 2, wherein the surfactant (B) has a concentration of from 1 ppm to 0.1% by weight, based on the total weight of the composition. An aqueous abrasive composition according to claim 1 or 2, characterized in that it contains at least one additional functional component (C) different from the components (A) and (B). A method of chemical mechanical polishing of a substrate having a patterned or unpatterned low-k or ultra-low-k dielectric layer having a dielectric constant of 3.5 or less, comprising the steps of: (1) fabricating the substrate material and comprising The following aqueous abrasive compositions are contacted at least once: (A) an abrasive particle selected from the group consisting of cerium oxide, cerium oxide, and mixtures thereof, and (Ba) at least one amphoteric nonionic surfactant selected from the group consisting of water-soluble or water-dispersible interfacial activity having the following a group consisting of: (b1a) at least one hydrophobic group selected from the group consisting of a linear alkyl group having 5 to 20 carbon atoms and a branched alkyl group (b1); and (b2) at least one a hydrophilic group selected from the group consisting of polyoxyalkylene groups of the following: (b21) oxyethylidene monomer units, and (b22) at least one substituted oxyalkylene monomer unit, wherein The substituent is selected from the group consisting of alkyl, cycloalkyl or aryl, alkyl-cycloalkyl, alkyl-aryl, cycloalkyl-aryl and alkyl-cycloalkyl-aryl; The polyoxyalkylene group contains the monomer units (b21) and (b22) which are randomly distributed, alternately distributed, gradiently distributed, and/or block-likely distributed; (2) chemically mechanically grinds the substrate at a certain temperature for a certain period of time. To fully achieve the desired flatness; and (3) removing the substrate from contact with the aqueous abrasive composition. The method of claim 9, wherein the low-k and ultra-low-k dielectric layer material is selected from the group consisting of porous and non-porous organically modified bismuth glass and organic polymers. The method of claim 10, wherein the organically modified bismuth glass is carbon doped cerium oxide (CDO). The method of claim 10, wherein the substrate further comprises at least one layer selected from the group consisting of: a dielectric layer other than the low-k and ultra-low-k dielectric layers, a barrier layer, and Metal layer. The method of claim 12, wherein the dielectric layer is a hafnium oxide layer. The method of claim 13, characterized in that the selectivity to cerium oxide is >3 in terms of material removal rate (MRR) compared to low-k and ultra-low-k dielectrics. Use of an aqueous abrasive composition according to any one of claims 1 to 8 for the manufacture of electrical, mechanical and optical devices.