STARTING MATERIAL FOR CHEMICAL VAPOR DEPOSITION COMPOSED OF ORGANOMANGANESE COMPOUND, AND CHEMICAL VAPOR DEPOSITION METHOD USING SAID STARTING MATERIAL FOR CHEMICAL VAPOR DEPOSITION

Abstract

A raw material for chemical deposition for producing a manganese thin film or a manganese compound thin film by chemical deposition method, including an organomanganese compound represented Chemical Formula 1 in which a cyclopentadienyl ligand and an isocyanide ligand are coordinated to manganese, which has basic characteristics as a raw material for chemical deposition and enables formation of a manganese thin film with a reducing gas such as hydrogen used as a reaction gas.

Claims

1. A raw material for chemical deposition for producing a manganese thin film or a manganese compound thin film by chemical deposition method, comprising: an organomanganese compound represented by the following Chemical Formula 1 in which a cyclopentadienyl ligand (L1) and an isocyanide ligand (L2) are coordinated to manganese, ##STR00016## wherein substituents R.sub.1 to R.sub.5 of the cyclopentadienyl ligand (L1) each are hydrogen, or a linear, branched or cyclic alkyl group having a carbon number of 1 or more and 4 or less, and a substituent R.sub.6 of the isocyanide ligand (L2) is a linear, branched or cyclic alkyl group having a carbon number of 1 or more and 4 or less.

2. The raw material for chemical deposition according to claim 1, wherein the substituents R.sub.1 to R.sub.5 of the cyclopentadienyl ligand (L1) are all hydrogen.

3. The raw material for chemical deposition according to claim 1, wherein the substituent R.sub.1 of the cyclopentadienyl ligand (L1) is any one of a methyl group, an ethyl group, a n-propyl group, an iso-propyl group, a n-butyl group, a sec-butyl group and a tert-butyl group, and R.sub.2 to R.sub.5 are all hydrogen.

4. The raw material for chemical deposition according to claim 1, wherein the substituent R.sub.6 of the isocyanide ligand (L2) is any one of a methyl group, an ethyl group, a n-propyl group, an iso-propyl group, a n-butyl group, a sec-butyl group and a tert-butyl group.

5. A chemical deposition method of a manganese thin film or a manganese compound thin film, comprising vaporizing a raw material including an organomanganese compound to obtain a raw material gas, and introducing the raw material gas onto a substrate surface under heating, wherein the raw material for chemical deposition defined in claim 1 is used as the raw material, and hydrogen is used as a reaction gas.

6. The chemical deposition method according to claim 5, wherein the method comprises applying a reducing gas as the reaction gas, introducing the raw material gas together with the reaction gas onto the substrate surface, and heating the gases.

7. The chemical deposition method according to claim 5, wherein a film forming temperature is 150° C. or more and 400° C. or less.

8. The raw material for chemical deposition according to claim 2, wherein the substituent R.sub.6 of the isocyanide ligand (L2) is any one of a methyl group, an ethyl group, a n-propyl group, an iso-propyl group, a n-butyl group, a sec-butyl group and a tert-butyl group.

9. The raw material for chemical deposition according to claim 3, wherein the substituent R.sub.6 of the isocyanide ligand (L2) is any one of a methyl group, an ethyl group, a n-propyl group, an iso-propyl group, a n-butyl group, a sec-butyl group and a tert-butyl group.

10. A chemical deposition method of a manganese thin film or a manganese compound thin film, comprising vaporizing a raw material including an organomanganese compound to obtain a raw material gas, and introducing the raw material gas onto a substrate surface under heating, wherein the raw material for chemical deposition defined in claim 2 is used as the raw material, and hydrogen is used as a reaction gas.

11. A chemical deposition method of a manganese thin film or a manganese compound thin film, comprising vaporizing a raw material including an organomanganese compound to obtain a raw material gas, and introducing the raw material gas onto a substrate surface under heating, wherein the raw material for chemical deposition defined in claim 3 is used as the raw material, and hydrogen is used as a reaction gas.

12. The chemical deposition method according to claim 6, wherein a film forming temperature is 150° C. or more and 400° C. or less.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0033] FIG. 1 illustrates a TG-DTA curve of an organomanganese compound according to Example 1 of First Embodiment;

[0034] FIG. 2 illustrates a TG-DTA curve of an organomanganese compound according to Example 2 of First Embodiment;

[0035] FIG. 3 illustrates a TG-DTA curve of an organomanganese compound according to Example 3 of First Embodiment;

[0036] FIG. 4 illustrates a TG-DTA curve of an organomanganese compound according to Example 4 of First Embodiment;

[0037] FIG. 5 is a diagram illustrating an analysis result, obtained through XPS, of a manganese thin film (No. 5) formed in First Embodiment; and

[0038] FIG. 6 is a diagram illustrating manganese atomic concentrations and oxygen atomic concentrations obtained through XPS of manganese thin films (No. 3 and No. 5) formed in First Embodiment.

DESCRIPTION OF EMBODIMENTS

[0039] First Embodiment: A best embodiment of the present invention will now be described. In this embodiment, four organomanganese compounds, in which substituents R.sub.1 to R.sub.5 of a cyclopentadienyl ligand (L1) were all hydrogen, or with only one of these set to an ethyl group, and a substituent R.sub.6 of an isocyanide ligand (L2) was set to an iso-propyl group or a tert-butyl group, were synthesized, and decomposition characteristics of these compounds were evaluated, and it was examined whether or not a manganese film could be formed with a hydrogen gas.

Example 1: Synthesis of (η.SUP.5.-cyclopentadienyl)-tris(2-isocyano-2-methylpropane)manganese

[0040] To 10 mL of a diethyl ether solution of 0.185 g (1.0 mmol) of bis(η.sup.5-cyclopentadienyl)manganese, 10 mL of a diethyl ether solution of 0.263 g (3.0 mmol) of 2-isocyano-2-methylpropane was added, followed by stirring at 25° C. for 30 minutes.

[0041] Thereafter, the solvent was distilled off under reduced pressure, and was subjected to purification with a silica gel column containing n-hexane/diethyl ether (v/v, 15:1) as a developing solvent. The solvent of the resultant solution was distilled off under reduced pressure to obtain 0.28 g (0.76 mmol) of a target product of (η.sup.5-cyclopentadienyl)-tris(2-isocyano-2-methylpropane)manganese (wherein R.sub.1 to R.sub.5 were hydrogen, and R.sub.6 was a tert-butyl group) in the form of an orange yellow solid (yield: 76%). The reaction formula in this example is as follows:

##STR00012##

Example 2: Synthesis of (η.SUP.5.-cyclopentadienyl)-tris(2-isocyanopropane)manganese

[0042] To 10 mL of a diethyl ether solution of 0.185 g (1.0 mmol) of bis(η.sup.5-cyclopentadienyl)manganese, 10 mL of a diethyl ether solution of 0.207 g (3.0 mmol) of 2-isocyanopropane was added, followed by stirring at 25° C. for 30 minutes.

[0043] Thereafter, the solvent was distilled off under reduced pressure, and purification was conducted with a silica gel column containing n-hexane/diethyl ether (v/v, 15:1) as a developing solvent. The solvent of the resultant solution was distilled off under reduced pressure to obtain 0.18 g (0.55 mmol) of a target product of (η.sup.5-cyclopentadienyl)-tris(2-isocyanopropane)manganese (wherein R.sub.1 to R.sub.5 were hydrogen, and R.sub.6 was an iso-propyl group) in the form of an orange yellow liquid (yield: 55%). The reaction formula in this example is as follows:

##STR00013##

Example 3: Synthesis of (η.SUP.5.-1-ethylcyclopentadienyl)-tris(2-isocyano-2-methylpropane)manganese

[0044] To 70 mL of a diethyl ether solution of 7.24 g (30.0 mmol) of bis(η.sup.5-1-ethylcyclopentadienyl)manganese, 30 mL of a diethyl ether solution of 7.48 g (90.0 mmol) of 2-isocyano-2-methylpropane was added, followed by stirring at 25° C. for 30 minutes.

[0045] Thereafter, the solvent was distilled off under reduced pressure, and was subjected to purification with a silica gel column containing n-hexane/diethyl ether (v/v, 15:1) as a developing solvent. The solvent of the resultant solution was distilled off under reduced pressure to obtain 10.8 g (29.2 mmol) of a target product of (η.sup.5-1-ethylcyclopentadienyl)-tris(2-isocyano-2-methylpropane)manganese (wherein R.sub.1 was an ethyl group, R.sub.2 to R.sub.5 were hydrogen, and R.sub.6 was a tert-butyl group) in the form of an orange yellow liquid (yield: 97%). The reaction formula in this example is as follows:

##STR00014##

Example 4: Synthesis of (η.SUP.5.-1-ethylcyclopentadienyl)-tris(2-isocyanopropane)manganese

[0046] To 10 mL of a diethyl ether solution of 0.241 g (1.0 mmol) of bis(η.sup.5-1-ethylcyclopentadienyl)manganese, 10 mL of a diethyl ether solution of 0.207 g (3.0 mmol) of 2-isocyanopropane was added, followed by stirring at 25° C. for 30 minutes.

[0047] Thereafter, the solvent was distilled off under reduced pressure, and was subjected to purification with a silica gel column containing n-hexane/diethyl ether (v/v, 15:1) as a developing solvent. The solvent of the resultant solution was distilled off under reduced pressure to obtain 0.19 g (0.54 mmol) of a target product of (η.sup.5-1-ethylcyclopentadienyl)-tris(2-isocyanopropane)manganese (wherein R.sub.1 was an ethyl group, R.sub.2 to R.sub.5 were hydrogen, and R.sub.6 was an iso-propyl group) in the form of an orange yellow liquid (yield: 54%). The reaction formula in this example is as follows:

##STR00015##

[0048] Examination of Vaporization Characteristic and Decomposition Characteristic: Each of the organomanganese compounds produced in the above-described examples was subjected to thermogravimetry-differential thermal analysis (TG-DTA) for examining the vaporization characteristic and the decomposition characteristic. In TG-DTA, TG-DTA2000SA manufactured by BRUKER was used, an aluminum cell was filled with a sample having a weight of 10 mg, and calorie change and weight change were observed at a temperature increasing rate of 5° C./min in a measurement temperature range of room temperature to 500° C. in a nitrogen atmosphere (under atmospheric pressure). FIGS. 1 to 4 illustrate TG-DTA curves of the organomanganese compounds of the respective examples.

[0049] Based on FIGS. 1 to 4, in the DTA curves of the organomanganese compounds of Examples 1 to 4 produced in the present embodiment, an endothermic peak or an exothermic peak derived from decomposition of the compound is observed in the vicinity of 200° C. It is noted that an endothermic peak in the vicinity of 65° C. of Example 1 is presumed to be derived from melting of the solid compound. Decomposition temperatures of the organomanganese compounds of Examples 1 to 4 were 187° C. (Example 1), 195° C. (Example 2), 187° C. (Example 3) and 209° C. (Example 4).

[0050] It was confirmed, according to the TG curves illustrated in FIGS. 1 to 4, that the decomposition of the organomanganese compounds of the respective examples smoothly proceed after the decomposition starts. As a residue generated after the decomposition, about 15% by mass of metal manganese was generated. Based on this examination on measurement results of the decomposition temperature obtained by TG-DTA and mass change caused after the decomposition, it was confirmed that the organomanganese compounds produced in the present embodiment can be decomposed at a temperature in the vicinity of 200° C., and that manganese can be smoothly precipitated after the decomposition.

[0051] Film Formation Test: The organomanganese compound of Example 3 produced in the present embodiment ((η.sup.5-1-ethylcyclopentadienyl)-tris(2-isocyano-2-methylpropane)manganese) was used as a raw material to form a manganese thin film with a CVD apparatus (hot wall CVD apparatus). A film formation test was conducted with the following film formation conditions:

[0052] Substrate: Si or SiO.sub.2

[0053] Film forming temperature: 200° C. or 300° C.

[0054] Sample temperature (vaporization temperature): 80° C.

[0055] Carrier gas: nitrogen (50 sccm)

[0056] Reaction gas: none (0 sccm) or hydrogen (50 sccm)

[0057] Chamber pressure: 5 torr, 15 torr or 50 torr

[0058] Film forming time: 15 min

[0059] In this film formation test, tris(2,2,6,6-tetramethyl-3,5-heptadionate)manganese, that is, a conventional organomanganese compound for chemical deposition, was also subjected to the film formation test as a comparative example. This organomanganese compound was synthesized by mixing a commercially available reagent, manganese (II) nitrate, with a 50% ethanol aqueous solution of 2,2,6,6-tetramethyl-3,5-heptadione, and adjusting pH of the resultant with a sodium hydroxide aqueous solution. The conditions for the film formation test were the same as those described above, and a hydrogen gas was used as the reaction gas.

[0060] After the film formation test, the thickness of the manganese thin film was measured in a plurality of positions by observation with an SEM (scanning electron microscope) or XRF (X-ray reflection fluorescence method) to calculate an average of the measured thicknesses. Results of the film formation test are shown in Table 1.

TABLE-US-00001 TABLE 1 Film Formation Conditions Raw Film Forming Film Forming Reaction Mn Test No. Material Substrate Temperature Pressure Gas*1 Thickness 1 Example Si 200° C.  5 torr 50 sccm  9.8 nm 2 3 SiO.sub.2  8.0 nm 3 50 torr 50.0 nm 4 Si 300° C. 15 torr  0 sccm.sup.*2 42.1 nm 5 SiO.sub.2 39.6 nm 6 Comparative Si 200° C.  5 torr 50 sccm — .sup.*3 7 Example 300° C. 15 torr  0 sccm — .sup.*3 *1The reaction gas was hydrogen. .sup.*2Film formation was performed only by heating in a carrier gas (N.sub.2) atmosphere. .sup.*3: Manganese film formation was not conducted.

[0061] As shown in Table 1, it was confirmed that a manganese thin film can be formed from a raw material comprising the organomanganese compound of Example 3 of the present embodiment ((η.sup.5-1-ethylcyclopentadienyl)-tris(2-isocyano-2-methylpropane)manganese). The organomanganese compound of the present embodiment can form a manganese film with a hydrogen gas used as a reaction gas. Besides, it was also confirmed that a manganese thin film can be formed only by heating without using a hydrogen gas (reaction gas).

[0062] The manganese thin films formed in the present embodiment were examined for the purity by XPS (X-ray photoelectron spectroscopy). In XPS, the formed manganese thin film was being etched, and in parallel, atomic concentrations in a thickness direction of various elements (Mn, 0, C, N and Si) were measured. The thin film was etched in consideration that the surface of the manganese thin film might be oxidized during transfer of the substrate from the CVD apparatus to an XPS analyzer.

[0063] As an example of analysis results obtained by XPS, the analysis result of a manganese thin film No. 5 shown in Table 1 is illustrated in FIG. 5. As is understood from FIG. 5, the manganese thin film No. 3 is oxidized in a top surface portion thereof, but contains pure manganese inside the thin film. FIG. 6 is a graph of comparing a manganese concentration (atomic concentration) and an oxygen concentration (atomic concentration) within each thin film obtained by XPS of the manganese thin films No. 3 and No. 5 of Table 1 after conducting etching for 1500 seconds. It is understood also from FIG. 6 that these manganese thin films contain pure manganese. Such an analysis result was similarly obtained in the other manganese thin films. Based on the results of XPS, it was confirmed that a pure manganese thin film can be formed from the organomanganese compound of the present invention. Besides, it was confirmed that the film formation of a pure manganese thin film can be conducted in either of a case where the film is formed with hydrogen used as a reaction gas (No. 3) and a case where the film is formed only by heating without using a reaction gas (No. 5).

[0064] As compared with the result of the organomanganese compound of the present embodiment, a manganese thin film could not be formed with a hydrogen gas in using the raw material of the conventional organomanganese compound (tris(2,2,6,6-tetramethyl-3,5-heptadionate)manganese) of the comparative example. The film formation could not be conducted only by heating in a nitrogen gas. Through comparison with this comparative example, the effect of the organomanganese compound of the present embodiment enabling film formation with a hydrogen gas is more clarified.

[0065] Second Embodiment: In this embodiment, a plurality of organomanganese compounds, in which substituents R.sub.1 to R.sub.5 of a cyclopentadienyl ligand (L1) were set to hydrogen, methyl, n-butyl or tert-butyl, and a substituent R.sub.6 of an isocyanide ligand (L2) was set to iso-propyl or tert-butyl, were synthesized, and decomposition characteristics of these compounds were evaluated. In addition, a film formation test was conducted on some of the compounds.

[0066] In the same manner as in First Embodiment, diethyl ether was used as a solvent to produce a solution of manganocene having corresponding substituents, an isocyanide solution was added thereto, and the resultant was stirred at 25° C. for 30 minutes to synthesize an organomanganese compound. In the same manner as in First Embodiment, TG-DTA was conducted to measure a decomposition temperature of each compound. Results are shown in Table 2.

TABLE-US-00002 TABLE 2 Substituent Decomposition R.sub.1~R.sub.5 R.sub.6 Temperature Example 5 R.sub.1 = tert-butyl, methyl 190° C. R.sub.2 = R.sub.3 = R.sub.4 = R.sub.5 = H Example 6 R.sub.1 = tert-butyl, iso-propyl 213° C. R.sub.2 = R.sub.3 = R.sub.4 = R.sub.5 = H Example 7 R.sub.1 = n-butyl, tert-butyl 193° C. R.sub.2 = R.sub.3 = R.sub.4 = R.sub.5 = H Example 8 R.sub.1 = methyl, iso-propyl 197° C. R.sub.2 = R.sub.3 = R.sub.4 = R.sub.5 = H Example 9 R.sub.1 = methyl, tert-butyl 187° C. R.sub.2 = R.sub.3 = R.sub.4 = R.sub.5 = H Example 10 R.sub.1 = R.sub.3 = methyl, methyl 184° C. R.sub.2 = R.sub.4 = R.sub.5 = H Example 11 R.sub.1 = R.sub.3 = methyl, tert-butyl 189° C. R.sub.2 = R.sub.4 = R.sub.5 = H Example 12 R.sub.1 = R.sub.2 = R.sub.3 = methyl 193° C. R.sub.4 = R.sub.5 = methyl, Example 13 R.sub.1 = R.sub.2 = R.sub.3 = iso-propyl 216° C. R.sub.4 = R.sub.5 = methyl,

[0067] Based on Table 2, also organomanganese compounds of respective examples produced in the second embodiment could be decomposed at a temperature of 180° C. to 220° C. Besides, it was confirmed that manganese was smoothly precipitated after the decomposition to generate manganese as a residue.

[0068] Among these examples, the film formation test was conducted on the compounds of Example 9 and Example 11. The film formation conditions of the film formation test were the same as those of First Embodiment, and a film thickness (average) was measured based on SEM and XRF. As a result, it was confirmed that a high-purity manganese thin film can be formed also from the organomanganese compounds of this embodiment. The formed manganese thin films all had a sufficient thickness in a range of 10 to 40 nm.

INDUSTRIAL APPLICABILITY

[0069] An organomanganese compound constituting a raw material for chemical deposition of the present invention has high thermal stability, and enables formation of a manganese film with a reducing reaction gas such as hydrogen. Besides, the compound has a vaporization characteristic suitable as a raw material for chemical deposition. The present invention is useful for formation of a seed layer or a barrier layer of various semiconductor devices.