JPH0770162A - Organic copper compound for forming copper thin film by chemical vacuum deposition of organic metal high in vapor pressure - Google Patents

Abstract

PURPOSE:To obtain an organic copper compound excellent in thermal stability on vaporization and useful as a vacuum deposition raw material when a copper thin film is formed by the chemical vacuum deposition method of an organic metal compound high in vapor pressure. CONSTITUTION:(eta2-1-Dimethylethylsilyl-3,3-dimethyl-1-butine) (1,1,1,5,5,5- hexafluoro-2,4-pentanedionato) copper (I) of the formula. The compound of the formula is obtained by reacting tert-butyl acetylene as a starting substance with butyl lithium, reacting the obtained lithium acetylide with the corresponding alkylsilane halide to produce the acetylene compound, subjecting the corresponding ketone and the corresponding ester to a Claisen condensation reaction therebetween to obtain a beta-dicarbonyl compound, and subsequently mixing the acetylene compound and the beta-dicarbonyl compound with cuprous oxide in a solvent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to metal organic chemical vapor deposition (hereinafter referred to as MOCVD) of a copper thin film such as wiring of a semiconductor device.
The present invention relates to an organic copper compound suitable for use as a vapor deposition material when formed by the method.

[0002]

2. Description of the Related Art When forming the above various copper thin films by MOCVD, the following (Chemical Formula 2) is used as a vapor deposition material.

[0003]

[Chemical 2]

(Η2-2-butyne) (hexafluoroacetylacetonato) copper (I) (hereinafter (η2-2-butyne) (hfa
c) It is well known that an organic copper compound consisting of Cu) is used. Further, the copper thin film,
For example, as shown in the schematic explanatory view in FIG. 1, the substrate 5 is placed on the heater 6 provided in the reaction furnace 7, and in the heating furnace 3 provided in connection with this, the organic copper compound in the vaporization container 2 is removed. The thermal decomposition type MO, which comprises vaporizing the vapor deposition raw material 1 and diffusing it into the reaction furnace 7 with a carrier gas 4 such as Ar to deposit decomposed copper on the heating substrate 5.
It is also known to be formed by a CVD (hereinafter abbreviated as thermal CVD) method.

[0005]

However, the above-mentioned thermal CVD
The conventional organocopper compound of (Chemical formula 2) used as a vapor deposition material in the method has a non-uniform vaporization rate with respect to the heating temperature during vaporization, and it is difficult to control it accurately. The deposition rate of the copper thin film becomes non-uniform, coupled with the recent trend of thinning due to high integration of semiconductor devices,
At present, it is difficult to control a uniform and dense film thickness. Further, the conventional organocopper compound described above also has a problem in thermal stability such that a decomposition reaction occurs in addition to the vaporization in the vaporization container 3 in FIG. 1 during heating in vaporization.

[0006]

From the above viewpoints, the inventors of the present invention have a uniform vaporization rate when producing a copper thin film by other MOCVD methods including the thermal CVD method, and have a thermal stability during vaporization. As a result of conducting research to find a vapor deposition material having excellent properties, (η2-1-dimethylethylsilyl-3,3-dimethyl-1-butyne) (1,1,1, 5,5,5-hexafluoro-2,4-pentanedionato) copper (I) (hereinafter (η2-DMESA)
(hfac) Cu (abbreviated as (hfac) Cu) is used as a vapor deposition raw material, the vapor deposition raw material is liquid near room temperature and has a tert-butyl group and a trialkylsilyl group. In addition, it was possible to obtain a stable vaporization rate, and it was obtained the research results that it shows excellent volatility and thermal stability.

The present invention was made based on the above-mentioned research results, and is represented by the above (Chemical formula 1) (η2-1-
Dimethylethylsilyl-3,3-dimethyl-1-butyne) (1,1,1,
It is characterized by an organocopper compound for forming a copper thin film by metalorganic chemical vapor deposition having a high vapor pressure, which comprises 5,5,5-hexafluoro-2,4-pentanedionato) copper (I). In the organocopper compound of the present invention, tert-butylacetylene is used as a starting material to prepare lithium acetylide from butyllithium, and the corresponding halogenated alkylsilane is used to synthesize the acetylene compound in (Chemical Formula 1). A β-dicarbonyl compound can be synthesized by Claisen condensation between corresponding ketones and esters, and these can be used by mixing with a cuprous oxide in a predetermined organic solvent.

[0008]

EXAMPLES Next, the organocopper compound of the present invention will be specifically described by way of examples. Dry and replace with nitrogen in a three-necked flask containing 8.21 g of t-butylacetylene and anhydrous tetrahydrofuran.
Add 160 ml and cool to 0 ° C. 62 ml of a 1.63 molar butyllithium hexane solution was added dropwise from the dropping funnel and stirred. Dimethylethylchlorosilane 12.3g at -30 ℃
Was added dropwise over 20 minutes, the temperature was returned to room temperature, and the mixture was stirred for 30 minutes. After heating under reflux for 3 hours, the mixture was neutralized with a saturated aqueous solution of ammonium chloride. The aqueous layer was extracted twice with ether, the organic layer and the extracted solution were combined, and the solvent was evaporated under reduced pressure. The residual oily substance was purified by distillation under reduced pressure to synthesize 10.9 g of 1-dimethylethylsilyl-3,3-dimethyl-1-butyne (hereinafter abbreviated as DMESA).

Subsequently, 130 ml of dry methylene chloride that had been sufficiently deaerated with nitrogen was poured into 12.5 g of Cu2O to prepare a suspension solution. 10.9 g of the above DMESA was added with vigorous stirring, and 12.5 g of 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (hereinafter abbreviated as Hhfac) was added drop by drop with a syringe. Dropped. The reaction system was stirred for 2 hours and then filtered under a nitrogen stream, and the filtrate was evaporated under reduced pressure at 35 ° C to obtain a green-yellow crude product. Purification is carried out by vacuum distillation at 80 ° C. and 0.2 torr, and the present organocopper compound 1 is a light yellow liquid.
8.5 g was obtained.

Identification of the obtained organocopper compound was carried out by 1 H-NMR,
Performed by elemental analysis and the like: 1H-NMR (CDCl3); 0.237
(S, 2H), 0.702 (q, 2H, J = 7.81), 1.00 (t, 3H, J
= 7.81), 1.354 (s, 9H), 6.098 (s, 1H).

For comparison purposes, a conventional organocopper compound represented by the chemical formula (2) was synthesized under the same conditions except that 2-butyne was used in place of DMESA.

2 and 3, for the purpose of evaluating the vaporization characteristics of the organocopper compound of the present invention (FIG. 2) and the conventional organocopper compound (FIG. 3) obtained as a result, a thermogravimetric curve (heating rate 10 ° C./min) ，
Nitrogen atmosphere).

Then, using the organocopper compound of the present invention and the conventional organocopper compound, by the thermal CVD method shown in FIG. 1, substrate: 1 inch square Ta, substrate temperature: 250 ° C., vaporization temperature: 70 ° C. A copper thin film was prepared under the conditions of pressure: 2 torr and carrier gas flow rate: 100 ccm of Ar, and the film thickness was measured every 10 minutes. The film thickness was measured from a cross-sectional SEM image of the film. The measurement results are shown in Table 1.

[0014]

[Table 1]

[0015]

From the results shown in FIGS. 2 and 3, the organocopper compound of the present invention can be completely vaporized at a temperature from room temperature to about 140 ° C., while the conventional organocopper compound is completely vaporized. In this case, about 10% of the residue was formed, which indicates that the organocopper compound of the present invention has excellent thermal stability during vaporization.

Further, from Table 1, in the organocopper compound of the present invention, the film thickness increases at a substantially constant rate with respect to the film formation time, and the film formation rate thereof is higher than that of the conventional organic copper compound. In the case of the conventional organic copper compound, it is clear that the tendency of decrease in the amount of film formation becomes remarkable from the time when the film formation time exceeds 30 minutes. Further, in the above examples, when the organocopper compound of the present invention was used, no generation of decomposed copper was observed in the vaporization vessel of the apparatus shown in FIG. Generation was observed. From this, the organic copper compound of the present invention is vaporized at a constant rate with respect to the film formation time without decomposing in the vaporization vessel, and is superior in thermal stability and volatility during vaporization to conventional organic copper compounds. It shows that it is a copper compound.

As described above, the organocopper compound of the present invention is a liquid near room temperature, has a stable vaporization rate, and is excellent in thermal stability upon vaporization, and therefore is useful as a film-forming raw material by the MOCVD method. Therefore, it can be used for manufacturing a copper thin film useful as a wiring material of a semiconductor device.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a thermal CVD method.

FIG. 2 is a thermogravimetric curve of the organocopper compound of the present invention.

FIG. 3 is a thermogravimetric curve of a conventional organocopper compound.

[Explanation of symbols]

 1. Deposition material 2. Vaporization container 3. Heating furnace 4. Carrier gas 5. Substrate 6. Heater 7. Reactor 8. Vacuum pump

Claims (1)

[Claims] 1. The following (Chemical formula 1) Represented by (η2-1-dimethylethylsilyl-3,3-dimethyl
-1-Butyne) (1,1,1,5,5,5-hexafluoro-2,4-pentanedionato) copper (I) with a high vapor pressure Compound.