Mononuclear bisamidate dicarbonyl complexes of ruthenium

Abstract

Mononuclear bisamidate dicarbonyl complexes of ruthenium selected from the group consisting of compounds of the formula Ru(CO)2[OC(R1)NR2]2, wherein the functional groups R1 are selected from -H, methyl, ethyl, propyl, isopropyl, cyclopropyl and isomeric butyl functional groups, wherein the functional groups R2 are selected from methyl, ethyl, propyl, isopropyl, cyclopropyl and isomeric butyl functional groups, wherein the functional groups R1 and R2 can be the same or different.

Description

[0001] DESCRIPTION

[0002] Mononuclear bisamidate dicarbonyl complexes of ruthenium

[0003] The invention relates to mononuclear bisamidate dicarbonyl complexes of ruthenium which, as ruthenium precursors, allow thin ruthenium layers or ruthenium oxide layers to be deposited onto substrates by means of CVD or ALD methods (CVD = chemical vapor deposition; ALD = atomic layer deposition). These new mononuclear bisamidate dicarbonyl complexes of ruthenium can also be used as homogeneous catalysts.

[0004] According to the current definition and also in the context of the present patent application, a CVD method is a method in which the vapor of a precursor is fed continuously from a heated reservoir into a reactor space under negative pressure conditions (0.1-10 mbar) and forms a layer there on heated contact surfaces of a substrate, for example contact surfaces of a semiconductor substrate, by thermal decomposition, for example in the temperature range of from 200 to 800°C. This continuous layer growth process can be supported by admixture of a co-reactant and / or by the inflow of an inert carrier gas such as nitrogen or argon.

[0005] According to the current definition and also in the context of the present patent application, an ALD method is a method in which the vapor of a precursor is pulsed in sequentially from a heated reservoir under negative pressure conditions (0.01-10 mbar) and in exchange with a coreactant in a reactor space. There, as a result of self-limiting chemical surface reactions, a layer is then formed on the contact surfaces of a substrate, for example contact surfaces of a semiconductor substrate, which are heated to a temperature, for example in the range of >50 to 300°C. Thus, the layer growth does not take place continuously during an ALD process, but rather in cycles. The process can be supported during each pulse by the inflow of an inert carrier gas such as nitrogen or argon.

[0006] Ruchi Gaur, Lallan Mishra, M. Aslam Siddiqi, and Burak Atakan in RSC Adv., 2014, 4, 33785- 33805 give an overview of ruthenium compounds that are usable for vapor deposition of ruthenium layers.

[0007] Open Inorganic Chemistry Journal, 2008, volume 2, pages 11-17 discloses mononuclear bisamidinate dicarbonyl complexes of ruthenium, Ru(CO)2[R2NC(R1)NR3]2 with the structural formula idealized in two-dimensional representation in particular where R1 = methyl and R2 = R3 = isopropyl or tert-butyl. The corresponding compound bis[N,N'-bis-tert-butylacetamidinate]dicarbonylruthenium, Ru(CO)2[tBuNC(CH3)NfBu]2 with the structural formula idealized in two-dimensional representation is also referred to herein as “Gordon's Precursor” and abbreviated as Ru(CO)2[N,N’- fBu2AAMD]2. “AAMD” stands for acetamidinate. Journal of the Electrochemical Society 2007, volume 154, pages D642-647 discloses the use of such bisamidinate dicarbonyl complexes of ruthenium for the production of ruthenium layers by CVD or ALD methods. However, said bisamidinate dicarbonyl complexes of ruthenium require high evaporation temperatures when used in CVD or ALD methods.

[0008] The object of the invention was to provide ruthenium compounds having improved properties with regard to a use for producing ruthenium oxide layers or ruthenium layers by means of CVD or ALD methods, in particular with regard to a use for producing ruthenium layers by means of CVD or ALD methods in the semiconductor field. The ruthenium compounds to be found should have high volatility and at the same time thermal stability; in other words, they should be able to be evaporated without decomposition at the lowest possible temperature at atmospheric pressure, in particular in the range of 100 to 200°C; the onset evaporation temperature to be used for the assessment can be determined thermogravimetrically, for example with the following measuring conditions: heating rate of 5 K / min, atmospheric pressure, flow rate = 200 mL nitrogen / min, horizontal flow. For this purpose, the thermogravimetric curve can be evaluated using the tangent method, wherein a first horizontal tangent to the curve is constructed in the region of maximum mass (start of measurement), and a second tangent is constructed at the inflection point of the thermogravimetric curve in the region of greatest mass decrease; the temperature read at the intersection of both tangents corresponds to the onset evaporation temperature. The ruthenium compounds to be found should also decompose into metallic ruthenium or form a ruthenium oxide layer, respectively, in the case of a CVD method by thermal treatment at temperatures above the boiling temperature, where applicable using a co-reactant, or in the case of an ALD method by reaction with a co-reactant at the normally prevailing process pressure. During the decomposition to form metallic ruthenium, it should be possible for them to be deposited rapidly in the form of layers that are as pure as possible without any or with only a few tolerable contaminations by foreign atoms, for example with <3 at.% in each case for carbon, oxygen, or nitrogen content. For the semiconductor field, this means that, of the ruthenium compounds to be found, ruthenium metal layers which are as pure as possible are to be deposited onto contact surfaces of semiconductors by CVD or ALD methods. The ruthenium compounds to be found should furthermore be sufficiently stable with respect to air and water, not be self-igniting, and be able to be synthesized and purified as easily as possible.

[0009] The invention achieves the object by providing mononuclear bisamidate dicarbonyl complexes of ruthenium selected from the group consisting of compounds of the formula Ru(CO)2[OC(R1)NR2]2, wherein the functional groups R1 are selected from -H, methyl, ethyl, propyl, isopropyl, cyclopropyl and isomeric butyl functional groups, wherein the functional groups R2 are selected from methyl, ethyl, propyl, isopropyl, cyclopropyl and isomeric butyl functional groups, wherein the functional groups R1 and R2 can be the same or different.

[0010] The term “isomeric butyl functional groups” used herein includes non-cyclic butyl and cyclobutyl.

[0011] The mononuclear bisamidate dicarbonyl complexes of ruthenium according to the invention represented by the formula Ru(CO)2[OC(R1)NR2]2have the following structural formula idealized in two-dimensional representation:

[0012] The ruthenium has the oxidation number +2 in the mononuclear bisamidate dicarbonyl complexes according to the invention. The anionic amidate ligands are bidentate coordinating ligands of the type (O-CR1-NR2)'.

[0013] Preferred examples of mononuclear bisamidate dicarbonyl complexes of ruthenium according to the invention include bis[N-isopropyl-tert-butylcarboxamidate]dicarbonylruthenium of the formula Ru(CO)2[(O-C(C(CH3)3)-N(CH(CH3)2)]2, also abbreviated herein as Ru(CO)2[N- / PrtBuAD]2. “AD” stands for amidate. Another preferred example is bis[N-tert-butyl- isopropylcarboxamidate]dicarbonylruthenium of the formula Ru(CO)2[(O-C(CH(CH3)2)- N(C(CH3)3)]2, also abbreviated herein as Ru(CO)2[N-fBu / PrAD]2.

[0014] The invention also relates to a process for the preparation of mononuclear bisamidate dicarbonyl complexes of ruthenium according to the invention. In the process according to the invention, a carboxamide of the formula R1C(O)NHR2 is first deprotonated with base to form a corresponding amidate (more precisely a carboxamidate) and then, optionally after isolating the amidate, reacted (a) with a ruthenium(ll) carbonyl compound having two or more CO ligands bound per ruthenium atom or (b) with a combination of RuCI3and carbon monoxide; in variant (b), the carbon monoxide has two functions: it causes a reduction of Ru3+to Ru2+, and it acts as a CO ligand, wherein it can be assumed that as a result intermediate ruthenium(ll) carbonyl species with two or more CO ligands bound per ruthenium atom are formed. The reaction takes place in the liquid phase, in particular in solution; it can be carried out in water as a non-organic solvent, in an aqueous organic solvent or solvent mixture, or preferably in a non-aqueous organic solvent or a non-aqueous mixture of organic solvents. Preferably, the non-aqueous organic solvents or the organic solvents constituting a non-aqueous mixture of organic solvents are aprotic organic solvents such as, for example, dioxane, tetrahydrofuran, methyl tert- butyl ether and diethyl ether. For a person skilled in the art, it goes without saying that it is expedient to work with the greatest possible exclusion of oxygen.

[0015] Examples of ruthenium(ll) carbonyl compounds having two or more CO ligands bound per ruthenium atom include [Ru(CO)3Ch]2, Ru(CO)2(PPh3)2Cl2, and representatives of the general formula Ru(CO)2[amidinate]2 such as Gordon's Precursor.

[0016] Examples of bases include lithium organyls; magnesium organyls, in particular Grignard compounds; zinc organyls; alkali metal hydrides, alkaline earth metal hydrides, alkali metal amides, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal hydrogen carbonates and alkali metal carbonates.

[0017] Using the example of ((CH3)2CH)C(O)NH(C(CH3)3), butyllithium and [Ru(CO)3Ch]2 the reaction sequence is as follows:

[0018] The mononuclear bisamidate dicarbonyl complexes of ruthenium according to the invention achieve the object explained at the beginning. They can be used as homogeneous catalysts. In particular, they can be used outstandingly as precursors for producing ruthenium layers or ruthenium oxide layers on substrates by means of CVD or ALD methods, in particular ruthenium layers in the semiconductor field, i.e., in particular for producing ruthenium layers on contact surfaces of semiconductor substrates. They can be evaporated, more precisely evaporated without decomposition, at atmospheric pressure in the temperature range of 100 to 200°C. In particular the following mononuclear bisamidate dicarbonyl complexes of ruthenium according to the invention are suitable for the deposition of a high-purity ruthenium layer on contact surfaces of semiconductor substrates by means of CVD or ALD methods:

[0019] Bis[N-isopropyl-tert-butylcarboxamidate]dicarbonylruthenium and bis[N-tert-butyl- isopropylcarboxamidate]dicarbonylruthenium

[0020] The mononuclear bisamidate dicarbonyl complexes of ruthenium according to the invention are superior to the bisamidinate dicarbonyl complexes of ruthenium mentioned at the outset with regard to the object explained, as a comparison of the compounds according to the invention bis[N-isopropyl-tert-butylcarboxamidate]dicarbonylruthenium and bis[N-terf-butyl- isopropylcarboxamidate]dicarbonylruthenium with Gordon's precursor shows. The thermogravimetric analysis of these three compounds (see Fig. 1) shows that the two compounds according to the invention can be evaporated at atmospheric pressure in the particularly preferred temperature range of 100 to 200°C, while Gordon's precursor only evaporates at 215°C. Thus, the mononuclear bisamidate dicarbonyl complexes of ruthenium according to the invention achieve the object explained at the beginning fully and in a superior manner to Gordon's precursor.

[0021] Examples

[0022] All reactions and handling of air- and moisture-sensitive compounds were carried out under a dry argon atmosphere (Air Liquide, 99.995%) by means of a conventional Schlenk technique. All organic solvents were dried (M Braun Solvent Purification System) and stored via molecular sieve (4 A) under an argon atmosphere. All vacuum operations (e.g., solvent removal, sublimation, vacuum distillation) were carried out at a pressure of 10'1to 10'2mbar. Sample preparations for analytical purposes were carried out in a glovebox under an argon atmosphere. All commercially available chemicals were used without further purification.

[0023] Analysis of the elements C, H and N was carried out using a CHNS analyzer from Elementar, model Vario Mikro Cube. The Ru content was determined after a microwave digestion on an ICP-OES from Spectro, model Spectro Acros. The oxygen content was calculated by summation of the weight percentage measurement results of C, H, N and Ru and subtraction from 100 wt.%.

[0024] For NMR spectroscopic characterization, an AVI 11 400, an AVI 11 300 Nanobay, or a Bruker DPX200 NMR spectrometer were used. All spectra were analyzed using the internal solvent signal (CeDsH) and analyzed with the software MestReNova v.10.0.2-15465 of Mestrelab Research S.L.

[0025] LIFDI-MS (liquid-injection field desorption ionization mass spectrometry) was measured on a JEOL AccuTof GCy (JMS-T100GCV) (JEOL, Tokyo, Japan) equipped with a LIFDI source from Linden CMS (Weyhe, Germany). The emitter heating current was set to 20 mA / min at a constant rate. Thermogravimetric analyses were carried out on a Hitachi STA 200, located in a glovebox flooded with nitrogen, at atmospheric pressure (sample size approximately 10 mg), at a heating rate of 5 K / min (N2, flow rate = 200 mL / min, horizontal flow). The curves thus determined were evaluated by the tangent method described above. of bisf / V, / V‘-bis-tert- butylacetamidinateldicarbonylruthenium, “Gordon's Precursor,” Ru(CO)2[N,N’-fBu2AAMD]2): The synthesis was carried out as described in the literature (R.G. Gordon et al., Open Inorg. Chem. J. 2008, 2, 11-17). The compound was obtained as a pale yellow solid. 1.70 (s, 6H, 2 N=C(-CH3)-N), 1.35 (s, 18H, 2 -C(CH3)3),

[0026] 1.23 (s, 18H, 2 -C(CH3)3). The tert-butyl groups are not magnetically equivalent.

[0027] Onset evaporation temperature: 215°C of the carboxamides underlyinq the free amidate liqands):

[0028] The carboxamides were prepared analogously to the procedure described in the literature (A.R.

[0029] Prosser et a / ., Org. Lett. 2010, 12, 3968-3971.).

[0030] The compound was obtained as a colorless solid. -CH(CH3)2), 1.27 (s,

[0031] N-isopropyl-tert-butylcarboxamide (1.12 g, 7.82 mmol, 4.0 equiv.) was dissolved in THF (25 mL), the solution was cooled to 0°C in an ice bath, and n-butyllithium (1.6 M in hexane, 4.88 mL, 7.81 mmol, 4.0 equiv.) was slowly added dropwise. After stirring at room temperature for one hour, the reaction solution was slowly added to a 0°C suspension of [Ru(CO)3Ch]2 (1.00 g, 1.95 mmol, 1.0 equiv.) in THF (50 mL). The reaction mixture was heated under reflux for 48 h, during which the originally orange suspension cleared and a clear red solution was obtained. All volatile components were removed in vacuo, leaving a waxy red solid. This was extracted with n-hexane (2 x 30 mL). After evaporation of the solvent of the extract, a pale yellow solid remained. Purification by sublimation (70°C at 1x10-2mbar) gave a colorless solid.

[0032] Elemental analysis:

[0033] C18H32N2O4 U (441.53 g / mol)

[0034] C H N O Ru

[0035] Calculated 48.97% 7.30% 6.34% 14.50% 22.89%

[0036] Found 48.82% 7.34% 6.39% 14.64% 22.81%

[0037] 1H-NMR (300 MHz, C6P6) 5 fppml = 3.70 (sept., 2H, -CH(CH3)2), 1.12 (s, 18H, -C(CH3)3), 1.02 (d, 6H, -CH(CH3)2), 0.88 (d, 6H, -CH(CH3)2). The methyl groups of the isopropyl units are not magnetically equivalent.

[0038] 13C-NMR (100 MHz, C6P6) 5 fppml = 199.2 (2C, -C(O)-C(CH3)3), 188.2 (2C, Ru-CO), 47.2 (2C, -CH(CH3)2), 40.1 (2C, -C(CH3)3), 27.7 (6C, -C(CH3)3), 24.6 (2C, -CH(CH3)2), 24.2 (2C, -CH(CH3)2). The methyl groups of the isopropyl units are not magnetically equivalent.

[0039] LIFPI-MS (m / z): 442.04 = [M]+

[0040] Onset evaporation temperature: 164°C

[0041] Example 4 according to the invention (preparation of bisfN-tert-butyl- isopropylcarboxamidateldicarbonylruthenium:

[0042] The synthesis was carried out analogously to example 3) according to the invention using N- te / Y-butylisopropylcarboxamide instead of N-isopropyl-tert-butylcarboxamide. A colorless solid was obtained.

[0043] Elemental analysis:

[0044] C18H32N2O4 U (441.53 g / mol)

[0045] Calculated 48.97% 7.30% 6.34% 14.50% 22.89%

[0046] Found 48.97% 7.30% 6.33% 14.53% 22.87%

[0047] 1H-NMR (300 MHz, 5 fppml = 2.37 (sept., 2H, -CH(CH3)2), 1.20 (d, 6H, -CH(CH3)2), 1.11 (d, 6H, -CH(CH3)2), 1.08 (s, 18H, -C(CH3)3). The methyl groups of the isopropyl units are not magnetically equivalent.

[0048] 13C-NMR (75 MHz, C6P6) 6 fppml = 199.5 (2C, -C(O)-CH(CH3)2), 188.6 (2C, Ru-CO), 51.6 (2C, -C(CH3)3), 34.4 (2C, -CH(CH3)2), 32.2 (6C, -C(CH3)3), 20.0 (2C, -CH(CH3)2), 19.2 (2C, -CH(CH3)2). The methyl groups of the isopropyl units are not magnetically equivalent.

[0049] LIFDI-MS (m / z): 442.10 = [M]+

[0050] Onset evaporation temperature: 178°C Fig. 1 shows a comparison of the results of the thermogravimetric analyses of Ru(CO)2[N- / PrfBuAD)]2, Ru(CO)2[N-fBu / PrAD]2, and Ru(CO)2[N,N’-fBu2AAMD]2.

Claims

CLAIMS1. Mononuclear bisamidate dicarbonyl complexes of ruthenium selected from the group consisting of compounds of the formula Ru(CO)2[OC(R1)NR2]2, wherein the functional groups R1 are selected from -H, methyl, ethyl, propyl, isopropyl, cyclopropyl and isomeric butyl functional groups, wherein the functional groups R2 are selected from methyl, ethyl, propyl, isopropyl, cyclopropyl and isomeric butyl functional groups, wherein the functional groups R1 and R2 can be the same or different.

2. The mononuclear bisamidate dicarbonyl complexes of ruthenium according to claim 1 selected from the group consisting of bis[N-isopropyl-tert- butylcarboxamidate]dicarbonylruthenium of the formula Ru(CO)2[(O-C(C(CH3)3)- N(CH(CH3)2)]2 and bis[N-tert-butyl-isopropylcarboxamidate]dicarbonylruthenium of the formula Ru(CO)2[(O-C(CH(CH3)2)-N(C(CH3)3)]2.

3. A process for the preparation of mononuclear bisamidate dicarbonyl complexes of ruthenium according to claim 1, wherein a carboxamide of the formula R1C(O)NHR2 is first deprotonated with base to form a corresponding carboxamidate and then, optionally after isolating the amidate, reacted (a) with a ruthenium(ll) carbonyl compound having two or more CO ligands bound per ruthenium atom or (b) with a combination of RuCI3and carbon monoxide.

4. The process according to claim 3, wherein the ruthenium(ll) carbonyl compound having two or more CO ligands bound per ruthenium atom is selected from the group consisting of [RU(CO)3CI2]2, Ru(CO)2(PPh3)2CI2, and representatives of the general formula Ru(CO)2[amidinate]2.

5. The process according to claim 3 or 4, wherein the base is selected from the group consisting of lithium organyls, magnesium organyls, zinc organyls, alkali metal hydrides, alkaline earth metal hydrides, alkali metal amides, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal hydrogen carbonates and alkali metal carbonates.

6. The use of a mononuclear bisamidate dicarbonyl complex of ruthenium according to claim 1 or 2 or prepared by a process according to any of claims 3 to 5 as a precursor for the production of ruthenium layers or ruthenium oxide layers on substrates by means of CVD or ALD methods.

7. The use of a mononuclear bisamidate dicarbonyl complex of ruthenium according to claim 1 or 2 or prepared by a process according to any of claims 3 to 5 as a precursor for the production of ruthenium layers on contact surfaces of semiconductor substrates by means of CVD or ALD methods.

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