EP4731740A1

EP4731740A1 - Alkaline composition, its use and a process for cleaning substrates comprising cobalt and copper

Info

Publication number: EP4731740A1
Application number: EP24732904.8A
Authority: EP
Inventors: Michael Lauter; Sabine FRISCHHUT; Jun Wu; Haci Osman GUEVENC; Sheng-Hsuan Wei; Mei Chin SHEN; Volodymyr Boyko; Andreas Klipp; Nadine ENGELHARDT; Coralie Sophie SCHNEIDER
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2023-06-20
Filing date: 2024-06-12
Publication date: 2026-04-29
Also published as: TW202500736A; WO2024260812A1; CN121399239A; KR20260026497A

Abstract

The presently claimed invention relates to an alkaline composition for cleaning a substrate comprising i) copper or copper alloy and ii) cobalt or cobalt alloy, the composition comprising: a) at least one pH adjustor selected from compound of formula (I), wherein Ra, Rb, Rd and Rf are independently of each other selected from unsubstituted linear or branched C₁-C₁₂ alkyl, Re is selected from unsubstituted linear or branched C₄-C₉ alkyl; such that the dashed line bond between Re and N is a single or double bond and Rd is absent when the dashed line bond is a double bond, and Ra, Rb, Re and Rf may be bonded to form one or more 6 or 7 membered ring; a) at least one complexing agent selected from C₂ to C₁₂ hydrocarbon having at least two sulfonic acid or carboxylic acid groups, b) at least one polymeric dispersing agent having a weight average molecular weight ≥ 1000 g/mol; and c) a solvent comprising water.

Description

Alkaline composition, its use and a process for cleaning substrates comprising cobalt and copper

Technical Field

The presently claimed invention relates to an alkaline composition, its use and a process for cleaning substrates comprising a copper or copper alloy and cobalt or cobalt alloy.

Background

The fabrication of electrical devices, in particular, semiconductor integrated circuits (ICs); liquid crystal panels; organic electroluminescent panels; printed circuit boards; micro machines; DNA chips; micro plants and magnetic heads; preferably ICs with LSI (large-scale integration) or VLSI (very-large-scale integration); as well as optical devices, in particular, optical glasses such as photo-masks, lenses and prisms; inorganic electro-conductive films such as indium tin oxide (ITO); optical integrated circuits; optical switching elements; optical waveguides; optical monocrystals such as the end faces of optical fibers and scintillators; solid laser monocrystals; sapphire substrates for blue laser LEDs; semiconductor monocrystals; and glass substrates for magnetic disks; requires high precision methods which involve inter alia surface preparation, pre-plaiting cleaning, post-etch cleaning and/or post-chemical polishing cleaning steps using high-purity cleaning compositions.

Particular care has to be taken in the fabrication of ICs with LSI or VLSI. The semiconductor wafers used for this purpose include a semiconductor substrate such as silicon, on which regions are patterned for the deposition of different materials having electrically insulative, conductive or semiconductive properties. In order to obtain the correct patterning, excess material used in forming the various layers on the substrates must be removed. Further, to fabricate functional and reliable ICs, it is important to have flat or planar semiconductor wafer surfaces. Thus, it is necessary to clean, remove and/or polish certain surfaces of a semiconductor wafers during the fabrication of the ICs before carrying out the next process steps.

The most processing operations involving wafer substrate surface preparation, deposition, plating, etching and chemical mechanical planarization (CMP) variously require cleaning operations to ensure that the ICs are free from contaminants that would otherwise deleteriously affect the function of the ICs, or even render them useless for their intended functions. For instance, one such problem is caused by the residues that are left on the substrates following CMP processing. During for example Cu-CMP, the copper ion concentration can exceed the maximum solubility of the copper-inhibitor complexes. Therefore, the copper- inhibitor complexes can precipitate from solution and can coagulate on the surface as a residue. Moreover, these residues can stick to the surface of the polishing pad and accumulate, eventually filling the grooves in the polishing pad. Additionally, abrasive particles and chemicals contained in the CMP slurries as well as reaction by-products, when left behind on the wafer surface can cause severe damage. Furthermore, the polishing of copper damascene structures containing low-k or ultra low-k dielectric materials such as carbon- doped oxides or organic films can generate carbon-rich particles that settle on to the wafer surface. To make matters worse these low-k or ultra low-k dielectric materials as well as silicon carbide, silicon nitride or silicon oxynitride CMP stop layers are very hydrophobic and hence are difficult to clean with water-based cleaning solutions.

Another residue-producing process common to IC manufacturing involves gasphase plasma etching to transfer the patterns of developed photoresist coatings (for forming vias and trenches) to the underlying layers, which may consist of hardmask, interlevel dielectric, etchstop layers. The post gasphase plasma etch residues, which may include chemical elements present on and in the substrate and in the plasma gases, are typically deposited on the back end of the line (BEOL) structures and, if not removed, may interfere with the subsequent silicidation and contact formation.

Recent improvements in wafer processing and fabrication have led to the use of new materials, especially metals and metal alloys — for the microelectronic device fabrication. For example, conventional barrier layer materials have been replaced with cobalt (Co) and cobalt alloys in integrated circuits to reduce the thickness of the layer and the size of the integrated circuits. Another approach is to use cobalt as new plug material in integrated circuits. As these new cobalt containing or cobalt alloy layers and plugs are introduced, there is a demand in industry for post - CMP removal/cleaning compositions which are capable of removing the post - CMP residue and contaminants (including said precipitated corrosion inhibitors) without deleteriously affecting said new cobalt layer materials.

Additionally, if the substrates comprise a metallization based, for example, on cobalt and copper (for example Co-liner integration scheme as described in US2012/0161320) and these surfaces can get in contact with the cleaning solution, care has to be taken care that the cleaning solution is compatible with both metals. This is particularly the case for Cu-PCC and PERR solutions. For PERR the metal structures are open only at the bottom of the vias, etched into the dielectric layer. But for post Cu CMP the upper surface of the metallization is completely exposed to the PCC solution. Because the metals or materials showing metallic conductivity are in galvanic contact (Co-liner integration scheme) and immersed in the PERR or PCC cleaning solution, galvanic corrosion might have to be considered as well. Examples of metals involved may be Ru, Pt, Co, Ir, Pd, Re, Rh, Ti, Ta, Mn, Ni, Al, Cr, V, Mo, Zr, Nb, W, Zr, Cu, their alloys and conductive material like TiN and TaN. Additionally, Cu might be the fill material.

US 2018/0371371 A1 and US 2019/002802 A 1 disclose an aqueous post CMP cleaning composition including a polyethylene glycol, an anionic polymer poly(acrylic acid), acrylic acid- maleic acid copolymers, polyaspartic acid, polyglutamic acid, polyvinylphosphonic acid, polyvinylsulfonic acid, poly(styrenesulfonic acid), polycarboxylate ethers, poly-phosphorous acids, and copolymers of the polymers thereof. On the other hand, US 10351809 B2 reveals cleaning composition and process for cleaning post-chemical mechanical polishing (CMP) residue and contaminants from a microelectronic device, comprising at least one organic amine, at least one solvent, at least one quaternary base, at least one complexing agent, at least one reducing agent, optionally at least one additional etchant, and optionally at least one cleaning additive, wherein the cleaning composition is substantially devoid of alkali hydroxides, alkaline earth metal hydroxides, and tetramethylammonium hydroxide. Mentioned compositions are aimed at cleaning substrates, particularly containing cobalt. However, despite these advances, the formulation of a suitable composition is often challenging. One additional hurdle that is often faced is the incompatibility or low solubility of the various components, that render the composition unsuitable for manufacture in a concentrated form. Thereby reducing their processability and economic viability. Therefore, there is unmet to further provide improved cleaning compositions.

Summary

Surprisingly, it was found that the compositions of the presently claimed invention as described hereinbelow provide surprisingly low cobalt and copper etching rates in addition to allowing high processability.

Accordingly, in one aspect, the presently claimed invention is directed to an alkaline composition for cleaning a substrate comprising i) copper or copper alloy and ii) cobalt or cobalt alloy, the composition comprising: a) at least one pH adjustor selected from compound of formula I

Formula I wherein

Ra, Rb, Rd and Rf are independently of each other selected from unsubstituted linear or branched C1-C12 alkyl,

Re is selected from unsubstituted linear or branched C4-C9 alkyl; such that the dashed line bond between Re and N is a single or double bond and Rd is absent when the dashed line bond is a double bond, and

Ra, Rb, Re and Rf may be bonded to form one or more 6 or 7 membered ring; b) at least one complexing agent selected from C2 to C12 hydrocarbon having at least two sulfonic acid or carboxylic acid groups, c) at least one polymeric dispersing agent having a weight average molecular weight > 1000 g/mol; and d) a solvent comprising water.

In another aspect, the presently claimed invention is directed to a concentrate for preparing a composition as described herein, the concentrate comprising: a) > 4.0 to < 40.0 wt.% of at least one pH adjustor; b) > 0.1 to < 3.0 wt.% of at least one complexing agent, c) > 0.01 to < 3.0 wt.% of at least one polymeric dispersing agent; and d) rest a solvent comprising water.

In another aspect, the presently claimed invention is directed to the use of the composition as described herein for removing

(a) post etch residue (PERR) or post ash residue (PARR), or

(b) chemical mechanical planarization (CMP) residues, from a substrate comprising (i) a cobalt or cobalt alloy surface and (ii) a copper or copper alloy surface.

In another aspect, the process processing a microelectronic device, the process comprising: (a) providing a microelectronic substrate that comprises (i) a cobalt or cobalt alloy surface and (ii) a copper or copper alloy surface having post etch residues, post ash residues, or chemical mechanical planarization (CMP) residues thereon;

(b) providing a composition as described herein; and

(c) contacting (i) the cobalt or cobalt alloy surface and (ii) the copper or copper alloy surface with the composition for a time and at a temperature effective to at least partly, preferably completely, remove the post etch residues, post ash residues, or chemical mechanical planarization (CMP) residues from the substrate.

In another aspect, the presently claimed invention is directed to a process for manufacturing of a semiconductor device, comprising the processing as described herein.

The presently claimed invention is associated with at least one of the following objectives:

(1) compositions that are capable of substantially and efficiently removing post-CMP residues and contaminants especially from a substrate that contains or consists of cobalt or cobalt alloys (e.g., cobalt as part of a layer or as plug) without deleteriously affecting the electrical materials and devices, especially without deleteriously affecting semiconductor integrated circuits and providing high quality surface finish.

(2) The compositions and the methods of the presently claimed invention aim to provide improved performance in inhibition of etching for both copper as well as cobalt.

(3) The composition of the presently claimed invention aims at providing a stable formulation with no precipitation or phase separation, especially in the alkaline regime.

(4) The composition of the presently claimed invention aims at providing easy-to-use, environmentally benign composition that allows easy processability and improved economic feasibility.

Detailed description

The following detailed description is merely exemplary in nature and is not intended to limit the presently claimed invention or the application and uses of the presently claimed invention. Furthermore, there is no intention to be bound by any theory presented in the preceding technical field, background, summary or the following detailed description.

The terms "comprising", "comprises" and "comprised of" as used herein are synonymous with "including", "includes" or "containing", "contains", and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. It will be appreciated that the terms "comprising", "comprises" and "comprised of' as used herein comprise the terms "consisting of', "consists" and "consists of".

Furthermore, the terms "(a)", "(b)", "(c)", "(d)" etc. and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the presently claimed invention described herein are capable of operation in other sequences than described or illustrated herein. In case the terms “(A)”, “(B)” and “(C)” or "(a)", "(b)", "(c)", "(d)", "(i)", "(ii)" etc. relate to steps of a method or use or assay there is no time or time interval coherence between the steps, that is, the steps may be carried out simultaneously or there may be time intervals of seconds, minutes, hours, days, weeks, months or even years between such steps, unless otherwise indicated in the application as set forth herein above or below.

In the following passages, different aspects of the presently claimed invention are defined in more detail. Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

Reference throughout this specification to "one embodiment" or "an embodiment" or “preferred embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the presently claimed invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" or “in a preferred embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment but may refer. Furthermore, the features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some, but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the subject matter, and form different embodiments, as would be understood by those in the art. For example, in the appended claims, any of the claimed embodiments can be used in any combination.

Furthermore, the ranges defined throughout the specification include the end values as well, i.e. a range of 1 to 10 implies that both 1 and 10 are included in the range. For the avoidance of doubt, the applicant shall be entitled to any equivalents according to applicable law. For the purposes of the presently claimed invention, ‘% by weight’ or ‘wt.% ‘as used in the presently claimed invention is with respect to the total weight of the coating composition. Further, sum of wt.% of all the compounds, as described hereinbelow, in the respective component adds up to 100 wt.-%.

For the purposes of the presently claimed invention, substrate is defined as a semiconductor wafer made of silicon or similar semi-metals used for making micro-electronic devices.

For the purposes of the presently claimed invention, polishing or cleaning refers to post- chemic-mechanical planarization (post CMP), wherein the alkaline composition as described herein is employable to remove debris and residues that remain on the semiconductor surface after the chemical-mechanical planarization (CMP) step. The CMP is well-known to target removal of specific layers on the semiconductor substrate involving a combination of chemical and mechanical action. Mechanical action is usually carried out by a polishing pad which is typically pressed onto the to-be-polished surface and mounted on a moving platen. 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. On the other hand, abrasive particles (such as silica particles) in the CMP compositions are essential for achieving “chemical” polishing. Additionally, the presence of specific chemicals (for instance oxidizers such as peroxides) in CMP composition are important for ensuring high removal rates for specific target layers/metals (such as copper and/or cobalt). However, the alkaline composition, as described herein, is essentially free from any abrasive particles (particularly silica particles) or oxidizers (particularly peroxides).

“Essentially free”, for the purposes of the present invention, means that the composition does not comprise any concentration of said component that can influence the cleaning functionality of the composition. Preferably the particle content is below 10 ppm, more preferably below 1 ppm, most preferably below the detection limit. In a preferred embodiment the composition is filtered before use to ensure particles concentration is below required value. For instance, preferably the composition is essentially free from abrasive particles and/or oxidizer, preferably the concentration of abrasive particles and/or oxidizers is below 10 ppm in the composition. However, any trace quantity of such particles/components that may remain on the semiconductor surface as part of the residue after CMP step, is not prejudicial to the cleaning application involving the alkaline composition described herein.

For the purposes of the presently claimed invention, a corrosion inhibitor is defined as a chemical compound forming a protective molecular layer on the surface of a metal. For the purposes of the presently claimed invention, the term "aqueous" means that the composition of the invention contains water. The water content can vary broadly from composition to composition. The alkaline composition, as described herein, is an aqueous composition and comprises at least 50.0 wt.%, preferably at least 60 wt.%, more preferably at least 80 wt.%, even more preferably at least 90.0 wt%, still more preferably at least 90.0 wt% water.

For the purposes of the presently claimed invention, the term "alkaline" means that the compositions of the invention have a pH in the range of from 7.5 to 14.0, preferably from 8.5 to 13.0 and, more preferably from 8.5 to 12.5, even more preferably from 9.0 to 12.0, most preferably from 10.5 to 11.9.

For the purposes of the presently claimed invention, the term “copper inhibitor” means a compound that inhibits static removal of copper from the substrate by etching. “Cobalt inhibitor” means a compound that inhibits static removal of cobalt from the substrate by etching.

All cited documents are incorporated herein by reference.

For the purposes of the presently claimed invention, the measurement techniques disclosed are well known to a person skilled in the art.

In an aspect of the presently claimed invention, an alkaline composition for cleaning a substrate comprising i) copper or copper alloy and ii) cobalt or cobalt alloy, the composition comprising: a) at least one pH adjustor selected from compound of formula I

Formula I wherein

The alkaline composition of the present invention comprises the components (a), (b), (c), (d) and optionally further components as described below.

(a) pH adjustor

According to the presently claimed invention, the composition comprises at least one pH adjustor selected from compound of formula I

Formula I wherein

Ra, Rb, Re and Rf may be bonded to form one or more 6 or 7 membered ring.

For the purposes of the presently claimed invention, a pH adjustor is defined as a compound which is added to the composition in order to have its pH value adjusted to the required value. As evidenced below in example section, the specific tertiary amine compounds of formula I or la ensure alkaline pH, while maintaining low static etch rate (SER) of both copper as well as cobalt. For the purposes of the presently claimed invention, the pH adjustor is selected from a tertiary amine and may not be selected from primary, secondary or quaternary ammonium groups.

Within the context of the presently claimed invention, the term “alkyl", as used herein, refers to an acyclic saturated unsubstituted aliphatic group, including linear or branched alkyl saturated hydrocarbon radicals, denoted by a general formula C_nH2n+i and wherein n is the number of carbon atoms such as 1 , 2, 3, 4, etc.

The unsubstituted linear C1-C12 alkyl is preferably selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, or dodecyl; more preferably selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and nonyl.

The unsubstituted branched C1-C12 alkyl is preferably selected from the group consisting of isopropyl, iso-butyl, neo-pentyl, 2-ethyl-hexyl, 2-propyl-heptyl, 2-butyl-octyl, 2-pentyl-nonyl, 2- hexyl-decyl, iso-hexyl, iso-heptyl, iso-octyl, iso-nonyl, iso-decyl, and iso-dodecyl, more preferably selected from the group consisting of iso-propyl, iso-butyl, neo-pentyl, 2-ethyl-hexyl, 2- propyl-heptyl, 2-butyl-octyl, 2-pentyl-nonyl, 2-hexyl-decyl, iso-hexyl, iso-heptyl, iso-octyl, and iso-nonyl.

Preferably, the composition comprises at least one pH adjustor selected from compound of formula I

Formula I wherein

Ra, Rb, Rd and Rf are independently of each other selected from unsubstituted linear C1-C9 alkyl,

Ra, Rb, Re and Rf may be bonded to form one or more 6 or 7 membered ring.

Preferably, Ra, Rb, Rd and Rf are independently of each other selected from unsubstituted linear or branched C1-C10 alkyl, even more preferably from unsubstituted linear or branched C1- C9 alkyl, more preferably from unsubstituted linear or branched Ci-Ce alkyl.

More preferably, Ra, Rb, Rd and Rf are independently of each other selected from unsubstituted linear C1-C12 alkyl, even more preferably from unsubstituted linear C1-C9 alkyl, most preferably from unsubstituted linear Ci-Ce alkyl. Preferably, Ra, Rb, Re and Rf may be bonded to form one or two or three 6 or 7 membered rings, more preferably they may be bonded to form one or two 6 or 7 membered rings.

It is understood to the skilled person that in case of bonding of Ra, Rb, Re and Rf to form ring structure(s), one or more H from alkyl group would be replaced by a C-C bond to form fused ring structures and the carbon groups attached to the N atom would be alkylene or -C(H2)- groups.

Preferably, the dashed line bond between Re and N is a single bond.

While diamines are well known for their ability to chelate with metals (by forming a five or six membered ring with the metal ion to be complexed), without being bound by theory, it is noted that such ring-forming diamines result in undesirable high copper and/or cobalt etching rates (evidenced by high SER values in example section below). For the purposes of the present invention, it is believed that the carbon chain length of Re in compound of formula I has to be carefully tailored in order to avoid ring-formation or chelation. Preferably Re is > C4 alkyl, more preferably Re is > C5 alkyl. On the other hand, compositions need to have suitably high watersolubility, particularly when being manufactured as concentrates, the increased solubility of the pH adjustor is important. In this regard, compounds of formula I having Re > C10 alkyl are noted to result in undesirable turbidity, thus making them unsuitable for commercial application (refer example section below). Preferably, Re is < C9 alkyl, more preferably Re is < Cs alkyl.

Preferably, Re is selected from unsubstituted linear or branched C4-C8 alkyl, more preferably from unsubstituted linear or branched Cs-Cs alkyl.

More preferably, Re is selected from unsubstituted linear C4-C9 alkyl, even more preferably from unsubstituted linear C4-C8 alkyl, most preferably from unsubstituted linear Cs-Cs alkyl.

Preferably, the pH adjustor is selected from compound of Formula la,

Formula la wherein Ra and Rc in formula la are bonded to form a 6 or 7 membered ring (A), more preferably to form a 7 membered ring (A) and Ra is selected from unsubstituted linear or branched C1-C12 alkyl and Rc is selected from unsubstituted linear C1-C9 alkyl.

More preferably Rc is selected from unsubstituted linear Ci-Ce alkyl, even more preferably from unsubstituted linear or branched C1-C5 alkyl, more preferably from unsubstituted linear C1-C4 alkyl.

Preferably, the alkaline composition comprises at least one pH adjustor selected from compound of formula I or formula la

Formula I or Formula la wherein

Ra, Rb, Rd and Rf are independently of each other selected from unsubstituted linear or branched C1-C12 alkyl, more preferably at least one of Ra, Rb, Rd and Rf in formula I is methyl, even more preferably at least two of Ra, Rb, Rd and Rf in formula I is methyl,

Re is selected from unsubstituted linear or branched C4-C9 alkyl; such that the dashed line bond between Re and N is a single bond,

Rc is selected from unsubstituted linear C1-C9 alkyl, and

Ra and Rc in formula la are bonded to form a 6 or 7 membered ring (A).

More preferably, Ra, Rb, Rd and Rf in formula I or la are independently of each other selected from unsubstituted linear or branched Ci-Ce alkyl and Rc is selected from unsubstituted linear C1-C4 alkyl.

Preferably, Ra, Rb, Rc, Re and Rf do not contain any further substitution, particularly do not contain groups selected from -COOH and derivatives thereof, -SO3H and derivatives thereof, - OH, -OR, or halogen.

Preferably, the pH adjustor, i.e., the compound of formula I or la, has a solubility in water (at 25°C) of at least 70 g/L, more preferably at least 150 g/L, even more preferably at least 200 g /L, more preferably at least 400 g /L, even more preferably the pH adjustor is completely miscible with water (soluble in any concentration) at 25 °C. The pH adjustor may be gaseous, liquid or solid, preferably solid or liquid, most preferably liquid (at 20 °C). Liquid amines are easier to process in comparison with gaseous amines and without being bound by theory, it is noted that gaseous amines (such as N,N,N-trimethylamine) may lead to an undesirable enhancement in etching rates, particularly if the substrate is exposed to the vapor of the composition and the pH adjustor shows a high vapor pressure. Preferably, the pH adjustor has a boiling point of at least 5 °C, more preferably at least 20 °C, even more preferably at least 35 °C (at 1 atm or 1013 mbar).

For the purpose of the present invention, the pKa refers to the most acidic proton associated with the N-atom on the pH adjustor, i.e., the compound of formula I or la. As mentioned, the pH adjustors play a crucial role in ensuring alkaline pH, but at the same time the pKa of the pH adjustor preferably, needs to be such that the environmental regulations and processing challenges are met. Substances labelled as highly corrosive substances, for instance, add processing and transportation challenges to manufacture.

Preferably, the pH adjustors have a pKa < 13.5, more preferably a pKa < 13.0, even more preferably a pKa < 12.5. Preferably, the pH adjustor has a pKa > 9.0, more preferably a pKa from > 9.2, even more preferably a pKa from 9.5 to 13.5, even more preferably from 9.9 to 12.1.

More preferably, the pH adjustor is selected from N,N,N,N-tetramethyl-1 ,6-hexandiamine,

N,N,N,N-tetramethyl-1,5-pentandiamine, N,N,N,N-tetramethyl-1 ,4-butandiamine, N,N,N,N- tetramethyl-1 ,7-heptandiamine, N,N,N,N-tetramethyl-1 ,8-octandiamine, 1 ,5- Diazabicyclo[4.4.0]dec-5-ene, 1 ,8-Diazabicyclo[5.4.0]undec-7-ene, 1 ,9- Diazabicyclo[6.4.0]dodec-8-ene .

Preferably, the concentration of the pH adjustor (a) is in the range of from > 0.02 wt.% to < 40.0 wt.%, based on the total weight of the composition.

The concentration of the pH adjustor (a) is preferably not more than 40.0 wt.%, more preferably not more than 39.0 wt.%, even more preferably not more than 38.0 wt.%, particularly not more than 36.5 wt.%, even more preferably not more than 35.0 wt.%, most preferably not more than 32.0 wt.%, based on the total weight of the composition. It is observed that concentration beyond 40.0 wt.% lead to colloidal instability of composition and/or phase separation, especially in presence of one or more water miscible organic solvent(s). The concentration of the pH adjustor (a) is preferably at least 0.02 wt.%, more preferably at least

O.05 wt.%, even more preferably at least 0.06 wt.%, particularly at least 0.07 wt.%, even more preferably at least 0.08 wt.%, still more preferably at least 0.085 wt.%, more preferably at least 0.09 wt.%, most preferably at least 0.1 wt.%, based on the total weight of the composition. The concentration of the pH adjustor (a) is more preferably in the range of from > 0.05 wt.% to < 38.0 wt.%, most preferably in the range of from > 0.1 wt.% to < 32.0 wt.%, based on the total weight of the composition.

(b) Complexing agent

According to the presently claimed invention, the alkaline composition for cleaning a substrate comprises at least one complexing agent selected from C2 to C12 hydrocarbon having at least two sulfonic acid or carboxylic acid groups.

In general, complexing agent in a liquid medium is able to dissolve metal salts or to prevent dissolved metal ions from forming insoluble precipitates by forming a well soluble complex with the metal ion and facilitate debris removal.

Preferably, the complexing agent is selected from C2 to C10 hydrocarbon, even more preferably from C3 to C10 hydrocarbon, having at least two sulfonic acid or carboxylic acid groups. The complexing agent may further comprise one or more N-donor, like amine or pyridine type N, or phenol-type OH groups for complexing metal ions. The complexing agent may comprise further functional groups like hydroxy or chloro and the like.

More preferably, the complexing agent is selected from C2 to C12 hydrocarbon having at least two carboxylic acid groups and optionally one or more chloro and/or hydroxy functional groups.

Even more preferably, the complexing agent is selected from alendronic acid, phthalic acid, citric acid, tartaric acid, tartronic acid, adipic acid, oxalic acid, malonic acid, aspartic acid, succinic acid, glutaric acid, glutamic acid, pimelic acid, sebacic acid, suberic acid, azelaic acid, sebacic acid, oxalic acid, malic acid, maleic acid, gluconic acid, pimelic acid, muconic acid, ethylenediaminetetraacetic acid, propylene diaminetetraacetic acid, N,N-bis(carboxymethyl) alanine, nitrilo-triacetic acid, diethylene-triamine-pentaacetic acid, bis(salicyliden) ethylendiamin, aminotris(methylenephosphonic acid), diethylene-triamine- pentakis(methylphosphonic acid), ethylene-diamine-tetra(methylene-phosphonic acid), or mixtures thereof.

More preferably, the complexing agent is selected from phthalic acid, citric acid, tartaric acid, tartronic acid, adipic acid, oxalic acid, malonic acid, aspartic acid, succinic acid, glutaric acid, glutamic acid, oxalic acid, malic acid, maleic acid, gluconic acid, ethylenediaminetetraacetic acid, propylene diaminetetraacetic acid, N,N-bis(carboxymethyl) alanine, nitrilo-triacetic acid, diethylene-triamine-pentaacetic acid, bis(salicyliden)ethylendiamin, aminotris (methylenephosphonic acid), diethylene-triamine-pentakis(methylphosphonic acid), ethylene- diamine-tetra(methylene-phosphonic acid), or mixtures thereof.

Even more preferably, the complexing agent is selected from citric acid, tartaric acid, tartronic acid, malonic acid, succinic acid, glutaric acid, malic acid, or mixtures thereof.

Most preferably, the complexing agent is citric acid.

Preferably, the complexing agent (b) is present in an amount in the range of from > 0.005 wt.% to < 3.0 wt.%, based on the total weight of the composition.

More preferably, the complexing agent (b) is present in an amount of not more than 3.0 wt.%, more preferably not more than 2.0 wt.%, most preferably not more than 1.0 wt.%, based on the total weight of the composition. The amount of (b) is preferably at least 0.005 wt.%, more preferably at least 0.008 wt.%, most preferably at least 0.01 wt.%, based on the total weight of the composition. The concentration of the complexing agent (b) is more preferably in the range of from > 0.05 wt.% to < 4.0 wt.%, most preferably in the range of from > 0.008 wt.% to < 1.0 wt.%, based on the total weight of the composition.

(c) Polymeric dispersing agent

According to the presently claimed invention, the composition comprises at least one polymeric dispersing agent (c) having a weight average molecular weight > 1000 g/mol.

Without being bound by theory, the polymeric dispersing agent facilitates in dispersing the silica particles that are left behind as residue after CMP cleaning. Parts of the dispersing agent for example adsorb on the surface of a particle to be dispersed. Another part of the dispersing agent for example reaches from the particle into the solution. Literature on the structure of adsorbed polymers is well known in the arts and can be found e.g. in Lipatov and Sergeeva, Adsorption of Polymers, 1974. The part of the dispersing agent in the solvent supports that the particles can be rinsed from the surface of a substrate to be cleaned. The improved interaction with the solvent will also increase the barrier between two particles or particle and substrate surface to make sure that agglomeration or redeposition will not happen. The chemical nature of the solvated part and the part adsorbed onto the particle surface can be the same or different. Analogue dispersing mechanisms and dispersing agents are well known in the arts and are described for example in T.F. Tadros, Applied Surfactants - Principles and Application, first edition from 2005, chapter 7.

As may be observed from Table 1 hereinbelow, the polymeric dispersing agent (C) comprising at least one polymeric dispersing agent (c) having a weight average molecular weight > 1000 g/mol prevents undesirable precipitation or agglomeration, while ensuring low cobalt and copper SER.

Preferably, the polymeric dispersing agent (c) having a weight average molecular weight > 1000 g/mol is selected from an anionic, a zwitterionic, non-ionic or cationic polymers. Among these anionic and non-ionic polymers are preferred. These polymers can be homo-polymers or co-polymers from anionic or non-ionic monomers.

Monomers can be ethylene oxide, propylene oxide, styrene, vinyl pyrrolidone, acrylamide, amino acids, carbon hydrates, vinyl alcohol, maleic acid, vinylsulfonic acid, vinylphosphonic acid, formaldehyde, phenolsulfonic acid, naphthalene sulfonic acid, phenol, or mixtures thereof.

More preferably, the dispersing agent is an anionic homopolymer or copolymer comprising monomeric units selected from sulfuric or phosphonic acid groups, or a non-ionic polymer comprising monomeric units selected from ethylene-oxide or vinylpyrrolidone.

Preferably, the polymeric dispersing agent (c) having a weight average molecular weight > 1000 g/mol is not selected from polymers or copolymers of acrylic acid. Without being bound by theory, the presence of polymers or copolymers of acrylic acid leads to an unwanted increase in cobalt etching rates (SER).

Preferred polymers are polyvinylpyrrolidone, polyethylenoxide, ethyleneoxide propyleneoxide copolymer, naphthalenesulfonic acid formaldehyde condensate, phenolsulfonic acid formaldehyde condensate, or naphthalenesulfonic acid phenolsulfonic acid formaldehyde mixed condensate. The polymers obtained from condensation of aromatic and aldehyde compound may also comprise phenolic, cresolic or xylenolic units.

According to the invention, the weight average molecular weight (M_w) of the polymeric dispersing agent > 1000 g/mol. Preferably, the weight average molecular weight (M_w) of the polymeric dispersing agent > 1100 g/mol, more preferably > 1500 g/mol, most preferably > 1800 g/mol. Polymers having M_w < 1000 g/mol are noted to be inactive or have low surface activity in terms of dispersibility. Preferably, the weight average molecular weight (M_w) of the polymeric dispersing agent < 100 000 g/mol, more preferably < 80 000 g/mol, even more preferably < 50 000 g/mol, most preferably < 20 000 g/mol. Polymers having M_w > 100 000 g/mol have an undesirable high viscosity as well as low aqueous solubility that makes processing difficult. The weight average molecular weight is determined according to gel permeation chromatography.

Preferably, the polymeric dispersing agent (c) are not selected from cationic polymer or copolymers. Without being bound by theory, it is expected that the use of cationic copolymers in the composition may lead to insufficient cleaning, especially with regards to silica removal. Additionally, the cationic polymers can interact negatively with carboxylic acid hydrocarbons (if present in the composition) and form unwanted emulsions. Preferably, the amount of cationic polymers or copolymers, like for example polyethyleneimine (PEI) or cationic polyacrylamide, in the composition is < 0.01 wt%, based on the total weight of the composition.

Preferably, the polymeric dispersing agent (c) is present in an amount in the range of from > 0.001 wt.% to < 3.0 wt.%, based on the total weight of the composition.

More preferably, the polymeric dispersing agent (c) is present in an amount of not more than 2.5 wt.%, even more preferably not more than 2.0 wt.%, most preferably not more than 1.5 wt.%, most preferably not more than 1.0 wt.%, based on the total weight of the composition. The amount of (C) is preferably at least 0.005 wt.%, more preferably at least 0.008 wt.%, most preferably at least 0.01 wt.%, based on the total weight of the composition. The concentration of the polymeric dispersing agent (c) is more preferably in the range of from > 0.005 wt.% to < 2.5 wt.%, even more preferably is in the range of from > 0.008 wt.% to < 1.5 wt.%, most preferably is in the range of from > 0.01 wt.% to < 1.0 wt.%, based on the total weight of the composition.

(d) Solvent comprising water

According to the presently claimed invention, the composition comprises a solvent comprising water (d).

Water is particularly preferred medium for the compositions of the presently claimed invention. Preferably, the solvent (d) consists essentially of water. The presence of water-miscible organic solvents in combination with water has no detrimental effect on the performance. Preferably, the solvent (d) can be water in combination with one or more water-miscible organic solvents. The term “water-miscible organic solvent” in the context of the present invention preferably means that an organic solvent fulfilling this requirement is miscible with water at least in a 1 :1 (w/w) ratio at 20 °C and ambient pressure. Preferably, the water-miscible organic solvent is selected from Ci to C4 alcohols such as isopropyl alcohols, dimethylsulfoxide DMSO, gamma butyrolactone, sulfolane, alkylene glycols and alkylene glycol derivatives such as ethylene glycol or propylene glycol. Particularly, preferred compositions of the present invention do not comprise one or more water-miscible organic solvents.

For the purposes of the presently claimed invention, if the amounts of the components other than (d) are in total y wt.%, based on the total weight of the composition, then the amount of (d) is (100-y) wt.% of the composition.

The amount of the solvent (d) in the composition is preferably not more than 99.99 wt.%, more preferably not more than 99.9 wt.%, most preferably not more than 99.8 wt.%, particularly preferably not more than 99.5 wt.%, particularly not more than 97.0 wt.%, for example not more than 95.0 wt.%, based on the total weight of the composition. The amount of the solvent (d) in the composition is preferably at least 30.0 wt.%, more preferably at least 50.0 wt.%, most preferably at least 55.5 wt.%, particularly preferably at least 62.5 wt.%, particularly at least 75.0 wt.%, for example at least 80.0 wt.%, based on the total weight of the composition.

The composition further comprises an optional additive selected from reducing agent, oxygen scavenger, wetting agent, biocide, or mixtures thereof. Preferably, the composition be essentially free from one or more of the optional additives. More preferably, the composition may be essentially free from wetting agent and/or reducing agent.

Reducing agent

From former process steps, e.g., CMP or etching steps, residues of oxidizers like peroxide, persulfate or periodate might be present and may lead to corrosion of small metal features on the wafer during the subsequent cleaning step. To prevent this, reducing agents can be optionally added to the composition to neutralize the remaining oxidizers. Preferably, the reducing agent is selected from organic compounds comprising at least one primary or secondary hydroxy group. A preferred type of reducing agents are saturated organic compounds comprising at least four hydroxy groups. A more preferred type of reducing agents are saturated organic compounds comprising at least four alcoholic hydroxy groups, where one of these hydroxy groups is a primary hydroxy group. Preferred reducing agents are pentaerythritol, tetrahydroxybutane, pentahydroxypentane, hexahydroxyhexane 1,4-sorbitan and the like. The compound may form an acetal compound for example with a carbon hydrate, like isomalt, or be a free molecule, like mannitol. A more preferred type of reducing agents are sugar alcohols comprising at least four hydroxy groups. Examples of such sugar alcohols are sorbitol, arabitol, arabinitol, isomalt, mannitol, threitol, erythritol, xylitol or lactitol. The compound may form an acetal compound for example with a carbon hydrate, like isomalt, or be a free molecule, like mannitol. A particularly preferred reducing agent is sorbitol or xylitol.

Preferably, the reducing agent is present in an amount in the range of from > 0.01 wt.% to < 7.0 wt.%, based on the total weight of the composition.

More preferably, the reducing agent is present in an amount of not more than 7.0 wt.%, more preferably not more than 5.0 wt.%, most preferably not more than 3.0 wt.%, based on the total weight of the composition. The amount of reducing agent is preferably at least 0.01 wt.%, more preferably at least 0.03 wt.%, most preferably at least 0.05 wt.%, based on the total weight of the composition. The concentration of the reducing agent is more preferably in the range of from > 0.05 wt.% to < 5.0 wt.%, most preferably in the range of from > 0.06 wt.% to < 3.0 wt.%, based on the total weight of the composition.

Oxygen scavenger

Ambient oxygen dissolved in the solvent may already be able to damage small metal patterns on a substrate. To prevent this, oxygen scavangers may be added.

Oxygen scavenger are typically unsaturated organic compounds comprising at least one C-C double bond. This double bond can be isolated or part of a conjugated or aromatic system. A preferred type of oxygen scavangers are furanon and its derivatives, like for example 2- furanon, 3-methyl-2-furanon, 4-hydroxy-2,5-dimethyl-3-furanon, 5-hydroxymethyl-2-furanon, 5- ethyl-3-hydroxy-4-methyl-2-furanon, ascorbic acid or erythorbic acid. More preferred are furanon derivatives comprising at least two OH-groups in the furanon-ring like ascorbic acid or erythorbic acid. Particularly preferred is ascorbic acid.

Another preferred type of oxygen scavengers are phenol derivatives. Examples are Tyrosin, dihydroxybenzene, its isomers hydroquinone, catechol and resorcin and derivatives like 4- methoxyphenol (MeHQ), trihydroxybenzene, its isomers like pyrogallol and phloroglucine and derivatives like gallic acid or tannin type compounds, tetrahydroxybenzene, its isomers and derivatives.

Most preferably, the oxygen scavenger is selected from ascorbic acid, 4-methoxyphenol or gallic acid.

Preferably, the composition is essentially free from oxygen scavenger. When present in the composition, the amount of the oxygen scavenger in the composition is preferably not more than 10.0 wt.%, more preferably not more than 8.0 wt.%, most preferably not more than 5.0 wt.%, based on the total weight of the composition. The amount of the oxygen scavenger in the composition is preferably at least 0.01 wt.%, more preferably at least 0.03 wt.%, most preferably at least 0.05 wt.%, particularly preferably at least 0.08 wt.%, particularly at least 0.1 wt.%, based on the total weight of the composition.

Wetting agent

The composition of the present invention may optionally comprise a wetting agent. Suitable wetting agents are well known in the art and are typically any molecule consisting of at least on hydrophobic and at least one hydrophilic part, such as surfactants.

Preferably, wetting agents may be selected from anionic, non-ionic or cationic surfactants, more preferably from non-ionic surfactants. More preferably, the wetting agents are selected from

- alkoxylated fatty alcohols- preferably the alkoxylated fatty alcohols are adducts of ethylene oxide, propylene oxide or higher alkylene oxides and Cs-C fatty alcohols fatty alcohols- particularly preferred are wetting agents from Plurafac LF series from BASF,

- alkyl polyglucoside- preferably from C8-C20 alkyl polyglucoside- particularly preferred are wetting agents from Glucopon series from BASF,

- C12 to C24 alkyl carboxylic acid or a sarcosine- preferably C12 to C20 alkyl sarcosine- particularly preferred are N-oleyl sarcosine, N-cocoyl sarcosine, N-lauroyl sarcosine, or 4-butyl-benzoyl-sarcosine.

Preferably, the wetting agent has a cloud point > 30 °C, more preferably > 35 °C, measured according to DIN 53917 in water. Even more preferably the cloud point is from > 30 °C to < 50°C, most preferably > 35 °C to < 45 °C, measured according to DIN 53917 in water. Preferably, the composition is essentially free from wetting agent. When present in the composition, the amount of the wetting agent in the composition is preferably not more than 10.0 wt.%, more preferably not more than 8.0 wt.%, most preferably not more than 5.0 wt.%, based on the total weight of the composition. The amount of the wetting agent in the composition is preferably at least 0.005 wt.%, more preferably at least 0.008 wt.%, most preferably at least 0.01 wt.%, particularly preferably at least 0.015 wt.%, particularly at least 0.018 wt.%, based on the total weight of the composition.

Composition

The properties of the composition may depend on the pH of the corresponding composition. According to the presently claimed invention, the alkaline composition has a pH in the range from > 7.5 to < 14.0. Preferably, the pH value of the composition is > 8.5, more preferably > 9.0, most preferably > 9.5, particularly preferably > 10.0, particularly most preferably > 10.5. The pH value of the composition is preferably < 14.0, more preferably < 13.5, most preferably < 13.0, particularly preferably < 12.5, particularly most preferably < 11.5. The pH of the composition is preferably in the range from > 8.5 to < 13.0, preferably from > 8.7 to < 12.5, more preferably from > 9.0 to < 11.5. For the purposes of comparison, the pH values mentioned here as well as in the example section refer to the diluted composition. Minor variation of values mentioned herein would be expected by skilled person when comparing the pH for concentrated form. In this regard a variation of pH in the range of ±1.5, more preferably of ±1.3 could be expected.

Preferably the composition is essentially free of any particles, particularly silica particles. Essentially free here means that the composition does not comprise any amount of particles that influences the cleaning functionality of the composition. Preferably the particle content is below 10 ppm, more preferably below 1 ppm, most preferably below the detection limit. In a preferred embodiment the composition is filtered before use.

Preferably the composition is essentially free of any oxidizers, particularly any peroxides. Essentially free here means that the composition does not comprise any amount of actively added oxidizers that increase the copper or cobalt corrosion, but specifically excluding ambient oxygen (O2) dissolved in the composition. Preferably the oxidizer content (except O2) in the cleaning composition is below 10 ppm, more preferably below 1 ppm. Most preferably the content of any oxidizer (except O2) is below the detection limit. Preferably, the composition is essentially free of any metal ions, such as sodium or calcium. While such metal ions are not actively added to the composition, presence of trace amounts of such metals, preferably in amounts below 10 ppm, more preferably below 1 ppm, would have no detrimental effect on the performance or cleaning functionality of the composition. While the absence of sodium or similar metal ions is preferred, their presence, for instance as part of a salt in one or more ingredient, does not introduce any detrimental effect towards to the performance of the composition.

Preferably, the composition is essentially free of any film-forming agents, in particular free of any triazoles, benzotriazole, substituted triazoles or derivatives thereof. While agents are not actively added to the composition, presence of trace amounts of such agents, preferably in amounts below 10 ppm, more preferably below 1 ppm, would have no detrimental effect on the performance or cleaning functionality of the composition.

A preferred embodiment of the presently claimed invention is directed to an alkaline composition comprising: a) > 0.02 to < 40.0 wt.% of the pH adjustor; b) > 0.005 to < 3.0 wt.% of the complexing agent selected from C2 to C12 hydrocarbon having at least two sulfonic acid or carboxylic acid groups, c) > 0.001 to < 3.0 wt.% of the polymeric dispersing agent having a weight average molecular weight > 1000 g/mol; and d) rest a solvent comprising water, as defined herein and to be defined based on the examples; all based on the total weight of the composition, wherein the pH of the composition is of from about 7.5 to about 13.0, preferably of from about 9 to about 11.0, and wherein the % amounts of the components add to 100 % by weight in each case. The concentrations of the components (a) to (d) may be varied within the preferred ranges described above.

Another preferred embodiment of the presently claimed invention is directed to an alkaline composition for cleaning a substrate comprising i) copper or copper alloy and ii) cobalt or cobalt alloy, the composition comprising: a) > 0.02 to < 40.0 wt.% ofthe pH adjustor; b) > 0.005 to < 3.0 wt.% of the complexing agent selected from C2 to C12 hydrocarbon having at least two sulfonic acid or carboxylic acid groups, c) > 0.001 to < 3.0 wt.% of the polymeric dispersing agent having a weight average molecular weight > 1000 g/mol; and d) rest a solvent comprising water, as defined herein and to be defined based on the examples; all based on the total weight of the composition, wherein the pH of the composition is of from about 7.5 to about 13.0, preferably of from about 9 to about 11.0, and wherein the % amounts of the components add to 100 % by weight in each case. The concentrations of the components (a) to (d) may be varied within the preferred ranges described above.

Another preferred embodiment of the presently claimed invention is directed to an alkaline composition for cleaning a substrate comprising i) copper or copper alloy and ii) cobalt or cobalt alloy, the composition comprising: a) > 0.02 to < 40.0 wt.% of the pH adjustor; b) > 0.005 to < 3.0 wt.% of at least one complexing agent selected from citric acid, tartaric acid, tartronic acid, malonic acid, succinic acid, glutaric acid, malic acid, or mixtures thereof, c) > 0.001 to < 3.0 wt.% of at least one polymeric dispersing agent having a weight average molecular weight > 1000 g/mol is selected from polyvinylpyrrolidone, polyethylenoxide, ethyleneoxide propyleneoxide copolymer, naphthalenesulfonic acid formaldehyde condensate, phenolsulfonic acid formaldehyde condensate, or naphthalenesulfonic acid phenolsulfonic acid formaldehyde mixed condensate; and d) rest a solvent comprising water, as defined herein and to be defined based on the examples; all based on the total weight of the composition, wherein the pH of the composition is of from about 7.5 to about 13.0, preferably of from about 9 to about 11.0, and wherein the % amounts of the components add to 100 % by weight in each case. The concentrations of the components (a) to (d) may be varied within the preferred ranges described above.

The compositions of the invention may be prepared by customary and standard mixing processes and mixing apparatuses such as agitated vessels, in-line dissolvers, high shear impellers, ultrasonic mixers, homogenizer nozzles or counterflow mixers, can be used for carrying out the mixing of the components of the compositions in the desired amounts.

It will be appreciated that it is common practice to make concentrated forms of the compositions to be diluted prior to use. For example, the compositions may be manufactured in a more concentrated form and thereafter diluted with water and optionally water-miscible solvents (together referred as diluent), or other components at the manufacturer, before use, and/or during use. Dilution ratios may be in a range from about 1.0 parts diluent to 0.01 parts composition concentrate to about 200 parts diluent to 1 part composition concentrate, preferably the ratio of the diluent to the concentrate is in the range from 150:1 to 10:1, more preferably from 120:1 to 20:1. It may particularly be prepared by diluting a concentrate comprising: a) > 4.0 to < 40.0 wt.%, preferably > 5.0 to < 38.0 wt.%, more preferably > 7.0 to < 32.0 wt.%, of at least one pH adjustor; b) > 0.1 to < 3.0 wt.%, preferably > 0.8 to < 3.0 wt.%, more preferably > 0.85 to < 2.0 wt.%, of at least one complexing agent, c) > 0.005 to < 3.0 wt.%, preferably > 0.008 to < 3.0 wt.%, more preferably > 0.01 to < 2.5 wt.%, of at least one polymeric dispersing agent; and d) rest a solvent comprising water. with water, a water-miscible organic solvent, or a combination thereof. Preferred dilution factors (by weight) are from about 30 and more. More preferred are 50 and more. Even more preferred are 75 and more. Even more preferred are 100 and more.

Application

The compositions of the invention are well suited for the methods of the invention.

The main purpose of the methods of the invention however is the processing of substrates useful for fabricating electrical devices, in particular, semiconductor integrated circuits (ICs), liquid crystal panels; organic electroluminescent panels; printed circuit boards; micro machines; DNA chips; micro plants and magnetic heads; more preferably ICs with LSI (large- scale integration) or VLSI (very-large-scale integration); as well as optical devices, in particular, optical glasses such as photo-masks, lenses and prisms; inorganic electro- conductive films such as indium tin oxide (ITO); optical integrated circuits; optical switching elements; optical waveguides; optical monocrystals such as the end faces of optical fibers and scintillators; solid laser monocrystals; sapphire substrates for blue laser LEDs; semiconductor monocrystals; and glass substrates for magnetic disks.

Preferably, the methods of the invention involve surface preparation, pre-plating cleaning, post-etch cleaning or post-CMP cleaning steps, in particular post-etch or post-CMP cleaning steps.

The cleaning compositions are particularly useful for

(a) post etch residue (PERR) or post ash residue (PARR), or

(b) chemical mechanical planarization (CMP) residues, from a substrate comprising (i) a cobalt or cobalt alloy surface and (ii) a copper or copper alloy surface. The methods of the invention are particularly well-suited for the processing of substrates useful for fabricating ICs with LSI or VLSI, in particular in the back end of the line (BEOL) processing.

The methods of the invention are most particularly well-suited for the post-CMP cleaning of semiconductor wafers in the fabrication of ICs with LSI or VLSI, in particular by the copper damascene or dual damascene process.

Accordingly, one embodiment relates to a kit including, in one or more containers, one or more components adapted to form the compositions described herein. Preferably, one container comprises the at least one pH adjustor and at least one complexing agent; and a second container comprises the remaining components, e.g., at least one complexing agent, at least one polymeric dispersing agent, solvent comprising water, and optionally other components described herein, for combining at the fabrication facility or the point of use.

In the use of the compositions described herein, the composition typically is contacted with the device structure for a sufficient time of from about 25 seconds to about 200 minutes, preferably about 5 minutes to about 60 minutes, at temperature in a range of from about 10 °C to about 80 °C, preferably about 20 °C to about 60 °C. Such contacting times and temperatures are illustrative, and any other suitable time and temperature conditions may be employed that are efficacious to achieve the required removal selectivity.

Following the achievement of the desired cleaning action, the composition can be readily removed from the microelectronic device to which it has previously been applied, e.g., by rinse, wash, or other removal step(s), as may be desired and efficacious in a given end use application of the compositions of the present invention. For example, the device may be rinsed with a rinse solution including deionized water, an organic solvent, and/or dried (e.g., spin-dry, N2, vapor-dry etc.).

The cleaning composition described herein may be advantageously used for post etch or post ash residue removal (PERR, PARR), post CMP cleaning, surface preparation, and pre-metal plating cleaning, particularly of a substrate comprising both a cobalt or cobalt alloy surface and a copper or copper alloy surface.

The cleaning composition described herein may be advantageously used in a process for the manufacture of a semiconductor device, comprising the step of (a) providing a microelectronic substrate that comprises (i) a cobalt or cobalt alloy surface and (ii) a copper or copper alloy surface having post etch residues, post ash residues, or chemical mechanical planarization (CMP) residues thereon;

(b) providing a composition as described herein;

(c) contacting (i) the cobalt or cobalt alloy surface and (ii) the copper or copper alloy surface with the composition for a time and at a temperature effective to at least partly remove the post etch residues, post ash residues, or chemical mechanical planarization (CMP) residues from the substrate.

Preferably the post etch residues, post ash residues, or chemical mechanical planarization (CMP) residues are completely removed from the substrate.

Preferably, the static etch rate (SER) of copper < 4.0 A/min, more preferably < 3.5 A/min, even more preferably < 3.3 A/min, most preferably < 3.0 A/min.

Preferably, the static etch rate (SER) of cobalt < 5.0 A/min, more preferably < 4.0 A/min, even more preferably < 3.0 A/min, most preferably < 2.5 A/min.

The static etch rates were measured by standard method as described herein in the example section.

The composition according to the presently claimed invention has at least one of the following advantages:

(1) A suitably improved performance in inhibition of etching for both copper as well as cobalt (as evidenced by low SER values).

(2) The composition of the presently claimed invention provides a stable formulation or dispersion, wherein no phase separation or agglomeration or precipitation occurs, especially in the alkaline regime.

(3) The composition of the presently claimed invention allows easy processability, such as compatibility towards industrially relevant steps such as microfiltration.

(4) The process of the presently claimed invention is easy to apply and requires as few steps as possible.

(5) The compositions and the methods of the presently claimed invention are formulated with components that are moderately or low corrosive, thus improving the economic feasibility, processability, packaging and transportation, among others.

(6) The composition of the presently claimed invention aims to provide suitably low etch rates, while preventing undesirable surface defects and ensuring high surface quality. Embodiments

In the following, there is provided a list of embodiments to further illustrate the present disclosure without intending to limit the disclosure to the specific embodiments listed below.

1 .An alkaline composition for cleaning a substrate comprising i) copper or copper alloy and ii) cobalt or cobalt alloy, the composition comprising: a)at least one pH adjustor selected from compound of formula I

Formula I wherein

Ra, Rb, Re and Rf may be bonded to form one or more 6 or 7 membered ring; b)at least one complexing agent selected from C2 to C12 hydrocarbon having at least two sulfonic acid or carboxylic acid groups, c)at least one polymeric dispersing agent having a weight average molecular weight

> 1000 g/mol; and d)a solvent comprising water.

2. The composition according to embodiment 1 , wherein Ra, Rb, Re and Rf may be bonded to form a compound of formula la,

Formula la, wherein Ra and Rc are bonded to form a 6 or 7 membered ring (A), more preferably to form a 7 membered ring (A) of Formula la. he composition according to any one of the embodiments 1 to 2, wherein Ra, Rb, Rd and Rf are independently of each other selected from unsubstituted linear or branched Ci-Ce alkyl and Rc is selected from unsubstituted linear C1-C4 alkyl. he composition according to any one of the embodiments 1 to 3, wherein the pH adjustor has a pKa is > 9.0, preferably from 9.0 to 12.0. he composition according to any one of the embodiments 1 to 4, wherein the dispersing agent is selected from polyvinylpyrrolidone, polyethylenoxide, ethyleneoxide propyleneoxide copolymer, naphthalenesulfonic acid formaldehyde condensate, phenolsulfonic acid formaldehyde condensate, or naphthalenesulfonic acid phenolsulfonic acid formaldehyde mixed condensate. he composition according to any one of the embodiments 1 to 5, wherein the complexing agent is selected from citric acid, tartaric acid, tartronic acid, malonic acid, succinic acid, glutaric acid, malic acid, or mixtures thereof. he composition according to any one of the embodiments 1 to 6, further comprising a reducing agent selected from sugar alcohols, particularly sorbitol, preferably in an amount of 0.01 to 7.0 wt.%, preferably 0.07 to 5.0 wt.%. he composition according to any one of the embodiments 1 to 7, is essentially free from triazoles, quaternary ammonium salts, alkanolamines, or derviatives thereof of. he composition according to any one of the embodiments 1 to 8, further comprising an oxygen scavenger selected from ascorbic acid, 4-methoxyphenol or gallic acid. The composition according to any one of the embodiments 1 to 9, wherein the solvent consists essentially of water. The composition according to anyone of embodiments 1 to 10, further comprising a water-miscible organic solvent, preferably in an amount of 0.1 to 20 wt.%. The composition according to anyone of the preceding embodiments, having a pH from 7.5 to 14.0, preferably from 9.0 to 12.5. The composition according to anyone of the preceding embodiments, comprising: a)> 0.02 to < 40.0 wt.% of the pH adjustor; b)> 0.005 to < 3.0 wt.% of the complexing agent, c)> 0.001 to < 3.0 wt.% of the polymeric dispersing agent; and d)rest a solvent comprising water.

14. A concentrate for preparing a composition according to anyone of the preceding embodiments, the concentrate comprising: a)> 4.0 to < 40.0 wt.%, preferably > 7.0 to < 38.0 wt.%, of the pH adjustor; b)> 0.1 to < 3.0 wt.%, preferably > 0.3 to < 3.0 wt.%, of the complexing agent, c)> 0.01 to < 3.0 wt.%, preferably > 0.1 to < 3.0 wt.%, of the polymeric dispersing agent; and d)rest a solvent comprising water.

15. Use of the composition according to any of claims 1 to 13 for removing

(a) post etch residue (PERR) or post ash residue (PARR), or

16. A process of processing a microelectronic device, the process comprising:

(a) providing a microelectronic substrate that comprises (i) a cobalt or cobalt alloy surface and (ii) a copper or copper alloy surface having post etch residues, post ash residues, or chemical mechanical planarization (CMP) residues thereon;

(b) providing a composition according to anyone of embodiments 1 to 13; and

17. A process for manufacturing of a semiconductor device, comprising the process according to embodiments 16.

While the presently claimed invention has been described in terms of its specific embodiments, certain modifications and equivalents will be apparent to those skilled in the art and are intended to be included within the scope of the presently claimed invention. Examples

The following materials were used in electronic grade purity. All amounts given for the compounds in the compositions are absolute amounts, i.e. excluding any water, in the overall mixture. pH adjustor:

A-1 N,N,N’,N’-tetramethyl-1,6-hexanediamine

A-2 1 ,8-Diazabicyclo[5.4.0]undec-7-ene

A-3 Tri-N-ethylamine (comparative)

A-4 Tri-N-propylamine (comparative)

A-5 N,N,N',N'-Tetramethyl-1 ,10-decanediamine (comparative)

A-6 N-Methylethanolamine (comparative)

A-7 N,N,N',N'-Tetramethyl-1,3-propane diamine (comparative)

A-8 2-(Dimethylamino)-2-methylpropan-1-ol (comparative)

A-9 2-Amino-2-methylpropan-1-ol (comparative)

A-10 Choline hydroxide (comparative)

A-11 1,4-Diazabicyclo[2.2.2]octane (comparative)

A-12 1,3,5-Triazine (comparative)

A-13 N-Ethylpyrrolidine (comparative)

A-14 1 ,5-Diazabicyclo[4.3.0]non-5-en (comparative)

A-15 1 ,1 ,3,3-Tetramethylguanidine (comparative)

Complexing agent:

B-1 Citric acid

B-2 Malonic acid

B-3 Tartronic acid

B-4 Adipic acid

B-5 Malic acid

B-6 Glutaric acid

B-7 Tartaric acid

B-8 Succinic acid

B-9 Glycine (comparative)

B-10 Etidronic acid (comparative)

B-11 Histidine (comparative)

Dispersing agent:

C-1 Vinylpyrrolidone homopolymer (Luviskol K17 from BASF; Mw - 10000 g/mol) C-2 Phenolsulfonic acid condensate with formaldehyde, phenol and urea, sodium salt (Tamol DN)

C-3 Polyethylene glycol (Pluriol E1500 E, M_w 1500 g/mol)

C-4 Acrylic resin (Joncryl 682; M_w- 1700 g/mol; comparative)

Solvent:

D-1 Water

D-2 Ethylene glycol

D-3 1 ,2-propylene glycol

D-4 Dimethylsulfoxide (DMSO)

Additives

Reducing agent:

E-1 D-sorbitol

E-2 Xylitol

Wetting agent:

F-1 alkoxylated predominantly unbranched fatty alcohols, and contains higher alkene oxides alongside ethylene oxide (Plurafac LF401; viscosity - 135 mPa s at 25°C measured with Brookfield at 60 rpm)

F-2 alkyl polyglucoside of Cs-C fatty alcohol (Glucopon 225DK; viscosity according EN 12092 using Brookfield LVT - 4000 mPa s at 23°C)

F-3 N-oleyl sarcosine (Sarkosyl O from BASF)

Composition

The components in the composition were thoroughly mixed and all mixing procedures were carried out under stirring. A concentrate typically contained the following composition -10 wt% pH adjustor, 0.5 wt% complexing agent and 0.6 wt% polymeric dispersing agent, and optionally 3.5 wt.% reducing agent, 3.0 wt.% wetting agent and 15.0 wt.% water-miscible solvent). Ultra-pure water (UPW) was used to make up the composition to 100wt.%. For etching experiments diluted compositions were employed by typically diluting the concentrate composition about 50 times. Tables 1 and 2 below provides further details of the tested compositions. Static etch rate (SER) experiments

Two cobalt and two copper blank wafer coupons (each 2x2 cm) were pre-etched in 1wt.% oxalic acid for 1 min each at room temperature. The coupons were rinsed with ultra-pure water and dried in air. The thickness of the cobalt and copper levels on the coupons were determined by XRF. The ready-to-use PCC formulation was heated up to 60 °C and two cobalt blank wafer coupons (2x2 cm) were dipped into the tempered solution for 3 min. The coupons were then rinsed with ultra-pure water and dried in air. The same procedure was repeated with two copper blank wafer coupons. The thickness of the wafer coupons was determined by XRF. The static etch rates (SER) were determined by calculating the difference in cobalt/copper level thickness before and after PCC solution treatment divided by the etching time of 3 min.

Turbidity measurements (nephelometry)

Turbidity of both concentrate as well as 50 times diluted compositions was measured using a Hach Lange TL2350 instrument (Hach Lange GmbH). The scattered light from the sample is measured at a 90-degree angle to the incident beam. The measurements are carried out using white light (tungsten; I = 340-850 nm). The nephelometer was calibrated using formazine standards. All samples showing a turbidity of < 1.3 NTU (NTU = nephelometric turbidity unit) are considered as not being turbid.

For further evaluation, the diluted compositions in Tables 1 and 2 were prepared by suitable dilution of concentrate composition. Herein, the final concentrations of the compositions were as follows- 0.012 wt.% polymeric dispersing agent, and optionally 0.07 wt.% reducing agent, 0.06 wt.% wetting agent and 0.3 wt.% water-miscible solvent. Additionally, all compositions contained pH adjustor in below mentioned concentrations, herein the molar concentrations were also considered to ensure the results from various compositions are comparable. Similarly, since complexing agents mentioned herein have different denticity, they were added in below mentioned concentrations to ensure the results remain comparable. Ultra-pure water (UPW) was used to make up the composition to 100wt.%. Table 1:

Table 1 contd.:

Table 2 - for comparative examples: the composition revealed turbidity in concentrate form

Table 2 - for comparative examples- contd.

Results

Preferably, the SER values for copper should be < 4.0 and for cobalt < 5.0. Examples 1-19 in Table 1 showed surprisingly low static etch rates on cobalt and copper. Also, the concentrate compositions, as mentioned above, are commercially important for easy transport. However, at higher concentrations, the overall compatibility and miscibility of the various essential components is low. The examples 1-19 of Table 1 were readily processable with no visible turbidity with solvent (water or water along with water-miscible solvents such as ethylene glycol). Similar results were obtained even when the compositions were formulated in concentrate form, for instance, compositions containing ~10 wt% pH adjustor and other components adjusted accordingly versus examples in Table 1. Similar results were also noted when alternate water- miscible solvents such as propylene glycol (D-3) or DMSO (D-4) were employed (refer examples 15-16 of Table 1). Optional ingredients such as wetting agent were also tested, and acceptable results were obtained (examples 17-19 in Table 1 comprising dispersing agents F-1 to F-3). While reducing agent was noted to be optional (refer example 1), its presence was also noted to provide acceptable results. Additionally, reducing agent xylitol (E-2) was also tested by replacing sorbitol (E-1) in example 2 of Table 1 and acceptable results were noted with regards to both SER as well as turbidity.

Replacement of one or more essential component(s) with component(s) no longer according to the present invention, lead to undesirable effects. For instance, comparative examples 1-3 and

11 in Table 2 comprising compounds A-3 to A-5 and A-13, instead of pH adjustors according to present invention, were noted to result in undesirable turbidity/precipitation. Similar undesirable turbidity was also noted for comparative example 17 in Table 2 containing acrylic resin (C-4; dispersing agent). The careful selection of various critical components (such as complexing agent and polymeric dispersing agent) is essential for ensuring low SER. It is therefore noteworthy, that the employment of increased concentration of complexing agent in examples 4-11 (refer Table 1) also resulted in an acceptably low SER.

Undesirably high SER values for either copper and/or cobalt was also noted when the composition was not according to the present invention. For instance, comparative examples 4 to 10,

12 and 13 in Table 2 comprising pH adjustors (A-6 to A-12, A14 and A15) not according to the present invention, showed high SER values. Similar undesirable results were also noted when complexing agent (comparative examples 14-16 in Table 2 comprising B-9 to B11) not according to the present invention, was employed in the compositions.

Claims

1 . An alkaline composition for cleaning a substrate comprising i) copper or copper alloy and ii) cobalt or cobalt alloy, the composition comprising: a)at least one pH adjustor selected from compound of formula I

Formula I wherein

> 1000 g/mol; and d)a solvent comprising water.

2. The composition according to claim 1 , wherein Rc is selected from unsubstituted linear or branched C2-C12 alkyl.

3. The composition according to any one of the claims 1 to 2, wherein Ra, Rb, Rd and Rf are independently of each other selected from unsubstituted linear or branched Ci-Ce alkyl.

4. The composition according to any one of the claims 1 to 3, wherein the pH adjustor has a pKa is > 9.0.

5. The composition according to any one of the claims 1 to 4, wherein the dispersing agent is selected from polyvinylpyrrolidone, polyethylenoxide, ethyleneoxide propyleneoxide copolymer, naphthalenesulfonic acid formaldehyde condensate, phenolsulfonic acid formaldehyde condensate, or naphthalenesulfonic acid phenolsulfonic acid formaldehyde mixed condensate.

6. The composition according to any one of the claims 1 to 5, wherein the complexing agent is selected from citric acid, tartaric acid, tartronic acid, malonic acid, succinic acid, glutaric acid, malic acid, or mixtures thereof.

7. The composition according to any one of the claims 1 to 6, is essentially free from triazoles, quaternary ammonium salts, alkanolamines, or derviatives thereof of.

8. The composition according to any one of the claims 1 to 7, wherein the solvent (d) consists essentially of water.

9. The composition according to anyone of the preceding claims, having a pH from 7.5 to

14.0.

10. The composition according to anyone of the preceding claims comprising: a)0.02 to 40.0 wt.% of the pH adjustor; b)0.005 to 3.0 wt.% of the complexing agent, c) 0.001 to 3.0 wt.% of the polymeric dispersing agent; and d)rest a solvent comprising water.

11 . A concentrate for preparing the composition according to anyone of the preceding claims, the concentrate comprising: a)4.0 to 40.0 wt.% of the pH adjustor; b)0.1 to 3.0 wt.% of the complexing agent, c)0.01 to 3.0 wt.% of the polymeric dispersing agent; and d)rest a solvent comprising water.

12. Use of the composition according to any of claims 1 to 10 for removing

(a) post etch residue (PERR) or post ash residue (PARR), or

13. A process of processing a microelectronic device, the process comprising: (a) providing a microelectronic substrate that comprises (i) a cobalt or cobalt alloy surface and (ii) a copper or copper alloy surface having post etch residues, post ash residues, or chemical mechanical planarization (CMP) residues thereon;

(b) providing a composition according to anyone of claims 1 to 10; and

14. A process for manufacturing of a semiconductor device, comprising the process according to claim 13.