WO2007028898A1

WO2007028898A1 - Mechanochemical polishing composition, method for preparing and using same

Info

Publication number: WO2007028898A1
Application number: PCT/FR2006/002058
Authority: WO
Inventors: Georges Michel; Bernard Larorie
Original assignee: Kemesys
Priority date: 2005-09-09
Filing date: 2006-09-06
Publication date: 2007-03-15
Also published as: FR2890658A1; FR2890658B1; WO2007028898B1

Abstract

The invention concerns a mechanochemical polishing composition comprising abrasive particles including molecules of a metal oxide, a metal oxidizing agent, a first chemical attack agent of metals, a pH regulating agent, optionally a second chemical attack agent of metallic compounds, in particular of tantalum and tantalum nitride, a corrosion inhibitor, and a solvent. The invention is characterized in that the metal oxide is prepared via a sol-gel process. The invention also concerns a method for preparing and using the inventive composition.

Description

CHEMICAL MECANO POLISHING COMPOSITION, PROCESS FOR PREPARATION AND USE

The present invention relates to a composition adapted to allow chemical mechanical polishing, more commonly known by the acronym CMP (of the English "Chemical Mechanical Polishing").

It also relates to a process for preparing such a composition, as well as its use for polishing.

More specifically, the invention relates, in its first aspect, to a chemical mechanical polishing composition comprising abrasive particles including molecules of a metal oxide, a metal oxidizing agent, a first metal chemical etchant, an agent pH regulator, optionally a second chemical agent for etching metal compounds, in particular tantalum and tantalum nitride, a corrosion inhibitor, and a solvent. Such a composition is known to those skilled in the art, in particular by the teaching of the published patent application US 2004/0046148.

In this document, the stability of the polishing composition is increased by the implementation of a coating of the abrasive particles and / or by the presence of conventional additives known as stabilizing agent polishing compositions.

In the field of chemical mechanical polishing, it is continuously sought to improve the polishing compositions of the thin layers in order to obtain microcomponents increasingly efficient.

In particular, the stability of the composition is one of the properties that it is interesting to increase in order to keep polishing performance as long as possible.

In this context, it is an object of the present invention to provide an improved polishing composition compared to those of the prior art, in particular compared to that of document US 2004/0046148.

To this end, the composition of the invention, moreover in accordance with the generic definition given in the preamble above, is essentially characterized in that the metal oxide is prepared by a sol-gel process.

The invention has the advantage of constituting a ready-to-use composition. In other words, the user in possession of the composition according to the invention can directly, without adding a constituent, use the composition in a polishing machine. The manipulation of the composition is thus reduced, which represents a saving of time and a comfort or a security, in particular when the composition has a non-neutral pH, for the user.

The invention has especially the advantage of excellent stability over time, without resorting to a coating of abrasive particles and / or the presence of specific additives. Its stability is at least equal to two months.

The stability of the polishing composition is understood to mean the physical and chemical stability, and in particular the stability of the pH, the stability of the concentration of the oxidizing agent, the stability of the particles in suspension and the stability of the average particle size measured by laser granulometry. .

Thanks to this stability, the composition of the invention can be prepared industrially, well in advance, to be ready for use, which gives it great ease of use and saves considerable time for the application. polishing operation.

In a preferred embodiment of the invention, the metal oxide is silicon dioxide.

Advantageously, the composition according to the invention comprises the solvent and, as a percentage of its total mass: between 1.25% and 5% of abrasive particles,

between 0.06% and 2.5% of oxidizing agent for metals,

between 0.125% and 0.5% of the first chemical metal etching agent, between 0.01% and 0.5% of pH control agent,

optionally, between 0.03% and 0.15% of the second chemical etching agent of the metal compounds, and between 0.015% and 0.15% of corrosion inhibitor. Most preferably, the composition according to the invention comprises deionized water as a solvent and, as a percentage of its total mass: between 1.25% and 5% of silicon dioxide as abrasive particles, between 0.06 and % and 2.5% hydrogen peroxide as the metal oxidizing agent, between 0.125% and 0.5% lactic acid as the first chemical etching agent for metals, between 0.01% and 0% 5% potassium hydroxide or ammonia as a pH regulating agent, optionally between 0.03% and 0.15% ammonium fluoride or potassium fluoride as the second chemical etchant metal compounds, and

between 0.015% and 0.15% of benzotriazole as a corrosion inhibitor. The pH control agent is for example present in an amount for adjusting the pH of said composition between 0 and 12, preferably between 4 and 8.

According to an advantageous version of the invention, the abrasive particles form aggregates whose mean size is between 10 and 150 nm, preferably between 30 and 120 nm.

The invention relates, according to its second aspect, to a process for the preparation of a composition in accordance with the invention, comprising the following steps: the solubilization of the metal oxidizing agent, of the first chemical etching agent for metals, of the second chemical etching agent of the compounds metal where applicable and the corrosion inhibitor in the solvent; adding the solution obtained in the preceding step in a suspension of metal oxide, for example concentrated to 20% by weight, for a period of two hours, with vigorous stirring; and adjusting the pH of the mixture obtained in the preceding step, in a range from 0 to 12 and preferably from 4 to 8, by adding the pH control agent.

According to its third aspect, the invention relates to the use of a composition according to the invention for the chemical mechanical polishing of layers applied to a substrate carrying at least one semiconductor microcomponent.

Preferably, at least one of the layers applied to the substrate is a metal layer comprising for example copper.

Advantageously, at least one of the layers applied to the substrate is a layer of insulating material, comprising, for example, silicon dioxide.

At least one of the layers applied to the substrate is preferably an adhesion layer comprising, for example, tantalum and / or tantalum nitride. Preferably, at least one of the layers applied to the substrate is an insulating layer comprising, for example, an iron-nickel alloy.

According to an advantageous version of the invention, the substrate is covered in the order of: a layer of insulating material, comprising silicon dioxide, of a multilayer barrier level comprising, from the layer of insulating material, a first adhesion layer comprising tantalum, a second adhesion layer comprising tantalum nitride, an insulation layer comprising an iron-nickel alloy, a third adhesion layer comprising nitride nitride, tantalum and a fourth adhesion layer comprising tantalum, and

a metal layer comprising copper. Other characteristics and advantages of the invention will emerge clearly from the detailed description which is given hereinafter, by way of indication and in no way limiting, with reference to the appended drawings in which: FIGS. 1 and 2 each represent a diagram of a stack of layers on a substrate carrying at least one semiconductor microcomponent, before and after chemical mechanical polishing with a composition according to the invention; and

FIG. 3 represents a diagram of implementation of the composition of the invention in a chemical mechanical polishing process.

In Figures 1 and 2, the elements A and A 'to be polished, each deposited on a substrate S, comprise three levels: an insulating level I, a level II called "barrier" and a level III conductor.

The insulating level I consists of a layer 1 of insulating material in which at least one pattern m is etched. This pattern m can be any pattern conventionally engraved in the field of the manufacture of microcomponents, such as a via or a trench.

Level III conductor consists of a layer

4 physically deposited metal, such as magnetron sputtering, or chemically, such as chemical vapor deposition or CVD and electroplating.

The level II barrier, deposited on the entire layer 1 of insulating material, consists in the element A, two layers 2, 3 of adhesion. In the element A ', the level II barrier is multilayer. It includes a total of four layers 2, 3, 6, 7 of adhesion and an insulation layer 5.

Preferably, the insulating material is silicon dioxide SiO ₂ and the metal forming the metal layer 4 is copper. Copper can be replaced by another metal conventionally used in the metal layers of microcomponents, such as tungsten and aluminum.

The adhesion layers 2, 3 are preferably a first tantalum adhesion layer 2 coated with a second tantalum nitride adhesion layer 3.

The adhesion layers 6, 7 are preferably a third tantalum nitride adhesion layer 6 coated with a fourth tantalum adhesion layer 7.

Tantalum and tantalum nitride can be respectively replaced by any other compound conventionally used in the adhesion layers of microcomponents, such as titanium and titanium nitride, in particular in the case where the metal layer 4 is based on tungsten.

The composition according to the invention is generally used for the chemical mechanical polishing of layers applied to a substrate S carrying at least one semiconductor microcomponent.

At least one of the layers applied to the substrate S is a metal layer 4 comprising, for example, copper. At least one of the layers applied to the substrate S is a layer 1 of insulating material, comprising, for example, silicon dioxide.

At least one of the layers applied to the substrate S is a layer 2, 3, 6, 7 of adhesion comprising, for example, tantalum and / or tantalum nitride.

At least one of the layers applied to the substrate S is an insulation layer 5 comprising, for example, an iron-nickel alloy.

Preferably, the substrate S is covered in order:

a layer 1 of insulating material, comprising silicon dioxide, a level II multilayer barrier comprising, from the layer 1 of insulating material, a first adhesion layer 2 comprising tantalum, a second adhesion layer 3 comprising tantalum nitride, an insulation layer 5 comprising an iron-nickel alloy, a third adhesion layer 6 comprising tantalum nitride and a fourth adhesion layer comprising tantalum, and

a metal layer 4 comprising copper. Conventionally, chemical mechanical polishing of elements such as elements A and A 'takes place in two stages. A first step is to polish largely the metal layer 4, of which there is however a residual layer. A second step consists in polishing this residual layer as well as the level II barrier layers, in order to complete the polishing on the insulating level I.

The composition of the invention is especially adapted to perform the second polishing step. According to the invention, the chemical mechanical polishing composition comprises abrasive particles including molecules of a metal oxide, a metal oxidizing agent, a first metal etching agent, a pH regulating agent, optionally a second agent for etching metal compounds, in particular tantalum and tantalum nitride, a corrosion inhibitor, and a solvent.

The metal oxide is synthetic, of a colloidal nature, and has a particle size in suspension of less than one micron.

Preferably, the metal oxide is silicon dioxide.

It is prepared by a sol-gel process, either by hydrolysis and condensation in the organic phase, for example in an alcohol-type solvent, of silicon-alkoxide type reactants, of formula Si (OR) ₄ in which R is a hydrocarbon-based chain . The most reactive commonly used is tetraethylorthosilicate or tetraethoxysilane or TEOS.

The method of manufacture of the silica gives the composition of the invention a stability of the order of several months, and at least two months.

In particular, the chemical purity of the silica, characterized by the absence of contaminating metal ions, makes it possible to preserve the oxidizing agent metals, such as hydrogen peroxide, in the composition for durations much longer than allowed by other types of silica.

In addition, the abrasive particles remain in suspension for several months because of their inertia vis-à-vis the other chemical constituents of the mixture. The absence of agglomeration phenomena of particles over time seems related to the chemical and electrical properties of their surface, resulting from their manufacturing process.

Furthermore, the composition according to the invention is stable over a wide pH range, which is not the case for compositions based on synthetic abrasive particles, not obtained by a sol-gel process.

According to a particular embodiment, the composition according to the invention comprises the solvent and, as a percentage of its total mass:

between 1.25% and 5% of abrasive particles, between 0.06% and 2.5% of metal oxidizing agent, between 0.125% and 0.5% of the first chemical etching agent for metals, 0.01% and 0.5% pH adjusting agent, optionally 0.03% to 0.15% second chemical etchant, and 0.015% to 0.15% d corrosion inhibitor. Preferably, the composition of the invention comprises deionized water as a solvent and, as a percentage of its total mass: between 1.25% and 5% of silicon oxide as abrasive particles, between 0.06% and 2.5% of oxygenated water as a metal oxidizing agent,

between 0.125% and 0.5% of lactic acid as the first chemical etching agent for metals, between 0.01% and 0.5% of potassium hydroxide or as ammonia control agent; pH, optionally between 0.03% and 0.15% of ammonium or potassium fluoride as the second chemical etching agent of the metal compounds, and - between 0.015% and 0.15% of benzotriazole, or BTA , as a corrosion inhibitor.

The pH regulating agent is more particularly present in an amount for adjusting the pH of said composition between 0 and 12, preferably between 4 and 8.

The chemical reagents that constitute the composition of the invention are preferably of high chemical purity, preferably greater than 99%. In particular, deionized water is ultra pure water. The silicon dioxide, or silica, constituting the abrasive particles, allows the removal of polishing materials during the polishing process through a mechanical abrasion action. The material removed may be the material itself or a transformation product resulting from a reaction between at least one material to be polished and at least one constituent of the composition. For example, a Cu-BTA complex may form on the surface of the copper layer and form an adherent layer which is removed by abrasion. Silicon dioxide can be replaced by any metal oxide. The term "metal oxide" means any oxide of a metal, a metal being any chemical element of the periodic classification to which a metal behavior is attributed, but also the silicon oxide SiO ₂ and the cerium oxide CeO ₂ . Thus, the silicon oxide SiU ₂ may in particular be replaced by aluminum oxide or Al ₂ O ₃ alumina. Oxygenated water, as an oxidizing agent for metals, in particular transition metals such as copper Cu, Fe iron, nickel Ni and tungsten W, allows a loss of electrons of the metal which then takes its place. oxidized form.

There are two cases of oxidation. In a first case, the metal is oxidized and forms a metal oxide or hydroxide, insoluble in the medium. We talk about passivation. In a second case, the metal forms a metal cation, soluble in the medium. We talk about corrosion.

Two parameters influence passivation and corrosion: the electrochemical potential E of the composition, conferred by the redox species, in this case hydrogen peroxide, and pH.

Oxygenated water may be replaced by any oxidant having a redox potential greater than that of the M / M ^{n +} couples possible from the metals M to be polished, for example the Cu / Cu ⁺ , Cu / Cu ²⁺ , Fe / Fe ²⁺ , Fe / Fe ³⁺ , Ni / Ni ²⁺ .

It is therefore preferred to choose for the composition of the invention an oxidant whose potential E is greater than 0.52 volts. The oxidant may therefore be chosen for example from permanganate ion, ferric ion, oxygen O ₂ , nitrate ion, iodate ion, chlorate ion, chromate ion, cerium ion and the peroxodisulfate ion.

Lactic acid, as the first chemical etching agent for metals, is a source of hydrogen ion H ⁺ , responsible for chemical etching, and a complexing anion of oxidized copper in Cu ⁺ and Cu ²⁺ forms. . The complexation between the lactate anion and the copper ions displaces the chemical reaction towards the dissolution of the copper metal, hence an amplification of the chemical attack. While remaining within the scope of the invention, lactic acid can be replaced by any other carboxylic acid. For example, the carboxylic acid is chosen from monoacids with a hydrocarbon chain such as formic acid HCOOH, acetic acid CH ₃ COOH, propanoic acid C ₂ H ₅ COOH and butanoic acid C ₃ H ₇ COOH, monoacids alpha or beta hydroxylated such as lactic acid and gluconic acid, diacids with a hydrocarbon chain such as oxalic acid, malonic acid, succinic acid and glutaric acid, diacids alpha or beta hydroxylated such as tartaric acid and malic acid, triacids hydroxylated alpha such as citric acid, and aromatic acids such as benzoic acid, phenylacetic acid and hydroxybenzoic acid.

Advantageously, the first metal etching agent is a mono-, di- or triacid carboxylic acid including a hydroxyl function at the alpha and / or beta position, such as lactic acid.

The function of the pH control agent is to provide H0 ^~ ions which are intended to neutralize at least partially the hydrogen ions released by the acid component. Preferably, it is chosen from KOH potash, NH ₄ OH ammonia, NaOH sodium hydroxide and NH ₃ ammonia, but may be any strong mineral base or any organic base.

The second etchant metal compounds, in particular tantalum and tantalum nitride, is selected so as to provide fluoride ions F ^". In effect, materials such as tantalum and tantalum nitride have a large resistance to chemical attack.We speak of inertia, but the fluoride ion F ^" is more aggressive on these materials than the ion H ⁺ or HO. ^" The fluoride ion is in the form of soluble salt, for example of potassium KF, sodium NaF, ammonium NH ₄ F, or in the form of hydrofluoric acid HF.

The corrosion inhibiting agent is conventionally benzotriazole BTA, or any derivative of the azole compounds. The role of the BTA is to prevent copper corrosion. For this, it forms an insoluble Cu '' - BTA '^"' complex, which is deposited on the surface of the material to be polished and which limits the phenomenon of etching of the metal and therefore of corrosion, which is explained by the rightward shift of the transformation reaction of the non-soluble metal Cu Cu ⁺ ions cuprous and / or cupric Cu ^2+, soluble species. The solvent, which is preferably water, acts as a vector of chemical reagents and abrasive particles during chemical mechanical polishing. It allows the intimate mixing of chemical reagents through their solubilization. It also allows the suspension of the abrasive particles. In addition, during polishing, it ensures the evacuation of polishing residues, such as reaction by-products and solid debris.

Advantageously, the solvent is a deionized water, that is to say a water free of metal ions such as sodium, potassium, magnesium and calcium. Its use allows the contamination of the polishing composition in alkaline and alkaline earth elements to be residual.

The composition according to the invention is therefore an aqueous dispersion, preferably silica, obtained by solubilization of the metal oxidizing agent, the first metal etching agent, the second chemical etching agent of the metal compounds, the case and the corrosion inhibitor in the solvent, followed by the addition of the solution thus obtained in a suspension of metal oxide, for example concentrated to 20% by weight, for a period of two hours, with vigorous stirring, then by adjusting the pH of the mixture thus obtained. The pH is adjusted in a range from 0 to 12 and preferably from 4 to 8, by the addition of the pH regulating agent, without affecting the chemical and physical stability of the suspension.

The composition thus obtained is a white opalescent liquid which has a dynamic viscosity of between 1.05 and 2 centipoises and a density of between 1.005 and 1.04. The elemental size of the silica abrasive particles is between 15 and 70 nr, and is preferably chosen to be equal to 60 nm.

The abrasive particles form aggregates whose average size is between 10 and 150 nm, preferably between 30 and 120 nm. The average size of these aggregates, or mean diameter of the particles in volume, is measured according to the technique of photon correlation spectroscopy. The average size variation of the aggregates, measured by laser granulometry, is less than 5% during the first two months following the manufacture of the composition.

The characteristics mentioned above are presented in the form of ranges of values because of the possible adjustments of the composition to obtain a performance in a given application.

In addition, the elementary particles and the silica aggregates are of substantially spherical morphology. They exhibit a suspension stability of at least two months. For at least the first two months after the manufacture of the composition, no sedimentation of these particles takes place.

The composition of the invention has a high purity, controlled by the level of purity of each of the constituents. The Na, Ca and Mg element contamination is less than 1 ppm. Contamination in elements Fe, Al, Ni, Ti, V, Cr, Mn, Co, Cu, Zn is less than 0.1 ppm.

The chemical stability of the composition of the invention is at least two months. During the first two months after the manufacture of the composition, the recorded variation in pH is less than 0.05 units and the variation of the hydrogen peroxide concentration, an unstable molecule by nature, is less than 3%.

The composition of the invention is homogeneous and ready for use; it does not require any add operation chemical reagent, nor any mechanical agitation operation prior to use.

The composition of the invention is implemented in conventional chemical mechanical polishing processes, on a polisher as shown in FIG.

For silicon disks whose diameter varies from 100 to 300 mm, the slice 8 to be treated, which may be one of the elements A and A ', is plated by its rear face 8a on a rack 9 while its front face 8b, on which are present polishing deposits, is applied on a lower plate 10 covered with a carpet 11 of plastic.

Rotational movements are applied to the rack 9 and to the lower plate 10 in order to standardize the linear speeds of passage of the belt 11 on the edge 8.

A variable pressure is applied by the rack 9 on the lower plate 10.

The mechanism of abrasion of the layers of the element A or A 'is ensured by the composition 12 of. polishing of the invention, continuously dispensed by a feeding device 13 on the belt 11 during the course of the process and maintained by the carpet 11 with a sponge effect. The composition of the invention is used in particular for the removal of metal deposits of Cu, Ta, TaN and optionally FeNi until reaching the insulating level I. Thus, the surplus 4a, 2a, 3a, 6a, 7a, 5a of conductive layer 4, layers 2, 3, 6, 7 of adhesion and insulation layer 5 are removed by polishing and the interconnections, consisting of layers polished 2b, 3b, 4b, 5b, 6b, 7b filling each pattern m, are disclosed.

The adhered polished layers 2b, 3b, 6b, 7b provide the dual function of adhesion of the insulating level I at the conductive level III and the conductive level III metal ion diffusion barrier towards the insulating level I. The polished layer 5b of insulation provides the electromagnetic isolation function of the conductive track constituted by the polished layer 4b metal.

After the polishing, the deposition operations of insulating material, etching, deposit of barrier levels and conductor are performed again, from the polished element B, B '. The electrical connections are for example made according to a "damascene" architecture, single or double. The composition according to the invention can be adjusted according to the polishing results referred to, namely the removal rates and selectivities targeted.

For example, for polishing objectives which are polishing rates SiO ₂ , Cu and multilayer barrier level all equal to 500 A / min, and therefore selectivities SiO ₂ / multilayer barrier level and Cu / multilayer barrier level equal to 1, an optimum composition comprises, as a percentage of its total mass: - 5% of silicon oxide as abrasive particles,

0.25% hydrogen peroxide at 30% by weight as a metal oxidizing agent,

0.5% lactic acid as the first chemical etching agent for metals,

0.1% to 1% of a 40% by weight potassium hydroxide solution or 30% by weight aqueous ammonia solution as a pH regulating agent to have a pH equal to 4.10 0.125 % of ammonium or potassium fluoride as the second chemical agent for etching metal compounds,

0.12% benzotriazole as a corrosion inhibitor, and 93.005% to 93.905% deionized water as the solvent. Example of application: The composition of the invention is used for the chemical mechanical polishing of an element having the stack of. layers of the element A 'shown in Figure 2, and more specifically a stack SiO ₂ / Ta / TaN / FeNi / TaN / Ta / Cu on a substrate S silicon-based Si.

In particular, the composition comprising deionized water is tested as a solvent and, as a percentage of its total mass: between 1.25% and 5% of silicon dioxide as abrasive particles,

between 0.06% and 2.5% of oxygenated water as a metal oxidizing agent,

between 0.125% and 0.5% of lactic acid as the first chemical etching agent for metals, between 0.01% and 0.5% of potassium hydroxide or ammonia as a pH regulating agent , between 0.03% and 0.15% of ammonium or potassium fluoride as the second chemical agent for etching metal compounds, and between 0.015% and 0.15% of benzotriazole as a corrosion inhibitor .

The SiO ₂ silica layer is obtained on a silicon substrate by TEOS CVD. The copper is deposited electrolytically.

The wafer or the element to be polished has a diameter equal to 200 mm.

Specific technical objectives are first set. The polishing rate must be greater than or equal to 350 Â / min for all materials encountered within the stack.

The process must be nonselective. In other words, the polishing rates must be equivalent for all the materials of the stack and the selectivities equal to 1.

In addition, it is desired to minimize the defects generated by the polishing. So, a goal to reach is the absence of corrosion mark at copper interconnections. Another objective is to minimize the zones of hollow, corresponding to the "dishing" effect in English, by limiting them to 2000 A on the patterns of copper of 100 microns wide and to 200 A on the lines of copper of 10 microns wide. The erosion level should be less than 100 Å on 10 micron wide copper lines spaced by 2 micron wide insulating barriers. The operating conditions are defined as follows. The polisher is a mechanical polisher with two rotating plates, with a polishing mat made of polyurethane (soft carpet).

The tray and rack speeds are respectively set at 75 rpm and 50 rpm. The pressure exerted by the rack on the tray is 5 psi.

The material removal rates imparted by the composition of the invention are evaluated by thickness measurements, before and after polishing, on monitor slices, on which the deposit uniformly occupies the surface of the wafer. We are talking about full plate deposit.

Thickness measurements are performed on the various metal deposits (Cu, Ta / TaN, FeNi) and on the insulating deposit (SiO ₂ ).

The surface topologies after polishing are evaluated on etched slices, either in the presence of patterns, by optical observations under the microscope and by surface profile measurements using a high resolution profilometer.

In this example of application, the implementation of the composition according to the invention makes it possible to obtain the following results.

The rates of removal of the different full-ply deposited materials are between 350 and 1500 A / min for the copper layer, between 450 and 1300 A / min for the Ta / TaN / FeNi / TaN / Ta barrier level and between 300 and 1100 Â / min for the SiO ₂ insulation level. From these removal rates, the calculated selectivities, as ratios of these speeds, are between 0.4 and 4 for the selectivity

Cu / multilayer barrier level, and between 0.6 and 1.8 for the SiC 2 selectivity / multilayer barrier level.

In addition, no corrosion is generated on metals and metal alloys. The trough and erosion levels obtained are also in line with the objectives set.

Semiconductor fabrication techniques and their applications on silicon disks, monocrystalline or epitaxial, or on any plane support where multiple layers of a semiconductor or photo emissive material, insulator and conductive materials have been deposited, use the post-depot polishing technique to partially plan or remove some of the stacked layers.

The interconnections of the elements made during this stack of successive layers, such as transistors, capacitors, resistors, valves, motors, and other components, are made based on conductive elements, for example based on copper.

The composition according to the invention can be used in the manufacture of consumables for the microelectronics, optics, and all areas requiring the production of flat surfaces, in the presence in particular of silica, Cu, Ta, TaN and optionally FeNi. The use of the composition of the invention may for example be considered in the manufacture of electromechanical microsystems or MEMS.

Claims

1 / chemical mechanical polishing composition comprising: abrasive particles including molecules of a metal oxide, a metal oxidizing agent, a first metal chemical etching agent, - a pH regulating agent, optionally, a second agent chemical etching of metal compounds, in particular tantalum and tantalum nitride, a corrosion inhibitor, and a solvent, said composition being characterized in that the metal oxide is prepared by a sol-gel process.

2 / The composition of claim 1, wherein the metal oxide is silicon dioxide.

3 / Composition according to claim 1 or 2, comprising the solvent and, as a percentage of the total mass of said composition: - between 1.25% and 5% of abrasive particles, between 0.06% and 2.5% of oxidizing agent for metals, between 0.125% and 0.5% of the first chemical etching agent for metals,

between 0.01% and 0.5% of pH control agent, optionally between 0.03% and 0.15% of second chemical agents for etching metal compounds, and between 0.015% and 0, 15% corrosion inhibitor.

4 / Composition according to any one of claims 1 to 3, comprising deionized water as a solvent and, as a percentage of the total mass of said composition: between 1.25% and 5% of silicon dioxide as abrasive particles,

between 0.06% and 2.5% of hydrogen peroxide as a metal oxidizing agent, between 0.125% and 0.5% of lactic acid as the first chemical etching agent for metals, between 0.01% and 0.5% of potassium hydroxide or ammonia as a pH regulating agent, optionally between 0.03% and 0.15% of ammonium or potassium fluoride as the second agent etching of the metal compounds, and between 0.015% and 0.15% benzotriazole as a corrosion inhibitor.

5 / A composition according to any one of claims 1 to 4, wherein the pH regulating agent is present in an amount to adjust the pH of said composition between 0 and 12, preferably between 4 and 8.

6 / A composition according to any one of claims 1 to 5, wherein the abrasive particles form aggregates whose average size is between 10 and 150 nm, preferably between 30 and 120 nm.

7 / A method for preparing the composition according to any one of claims 1 to 6, characterized in that it comprises the following steps: - the solubilization of the metal oxidizing agent, the first chemical etching agent of metals the second chemical agent for etching the metal compounds, if any, and the corrosion inhibitor in the solvent; the addition of the solution obtained in the preceding step in a suspension of metal oxide, for example concentrated at 20% by weight, for a period of two hours, with vigorous stirring; and adjusting the pH of the mixture obtained in the previous step, in a range from 0 to 12 and preferably from 4 to 8, by adding the pH control agent.

8 / Use of the composition according to any one of claims 1 to 6 for the chemical mechanical polishing of layers applied to a substrate S carrying at least one semiconductor microcomponent.

9 / The use of claim 8, wherein at least one of the layers applied to the substrate S is a metal layer 4 comprising for example copper.

10 / The use of claim 8 or 9, wherein at least one of the layers applied to the substrate S is a layer 1 of insulating material, comprising for example silicon dioxide.

11 / Use according to any one of claims 8 to 10, wherein at least one of the layers applied to the substrate S is a layer 2, 3,

6, 7 comprising, for example, tantalum and / or tantalum nitride.

12 / Use according to any one of claims 8 to 11, wherein at least one of the layers applied to the substrate S is an insulation layer 5 comprising for example an iron-nickel alloy.

13 / Use according to any one of claims 8 to 12, wherein said substrate S is covered in the order of: - a layer 1 of insulating material, comprising silicon dioxide,

a level II multilayer barrier comprising, from the layer 1 of insulating material, a first adhesion layer 2 comprising tantalum, a second adhesion layer 3 comprising tantalum nitride, an insulation layer 5 comprising an iron-nickel alloy, a third adhesion layer 6 comprising tantalum nitride and a fourth adhesion layer 7 comprising tantalum, and

a metal layer 4 comprising copper.