JP2785671B2 - Organic silver compounds for forming silver thin films by metalorganic chemical vapor deposition with high vapor pressure - Google Patents

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 "M") for forming a silver thin film such as a contact and wiring of a semiconductor device.
The present invention relates to an organic silver compound suitable for being used as a vapor deposition material when formed by the OCVD method.

[0002]

2. Description of the Related Art In forming the above various silver thin films by MOCVD, for example, the following (Chemical Formula 2)

[0003]

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(1,5-cyclooctadiene)
(1,1,1,5,5,5-hexafluoro-2,4-
Pentandionato) silver (I) [hereinafter (1,5-cod)
Ag (hfac)] or the following (Formula 3)

[0005]

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(Trimethylphosphine) (1,
1,1,5,5,5-hexafluoro-2,4-pentanedionato) silver (I) [(Me3P) Ag (hfa
It is well known that an organic silver compound or the like which is abbreviated as c) is used. Further, as shown in the schematic explanatory view of FIG.
The substrate 5 is placed on a heater 6 provided therein, and in a heating furnace 3 provided in connection therewith, the vapor deposition raw material 1 made of an organic silver compound in the vaporization vessel 2 is vaporized.
It is also known that it is formed by a thermal decomposition type MOCVD (hereinafter abbreviated as thermal CVD) method comprising diffusing silver into the reaction furnace 7 with a carrier gas 4 such as r and depositing decomposition silver on the heating substrate 5. Have been.

[0007]

However, the above thermal CV
The conventional organic silver compounds of the above (Chemical Formula 2) and (Chemical Formula 3) used as the vapor deposition raw material in the method D are extremely unstable with respect to the heating temperature during vaporization. In the middle vaporization container 3, there is a problem in the thermal stability of the compound such that the organic silver compound mostly causes a thermal decomposition reaction in addition to vaporization, so that a uniform vaporization rate cannot be stably secured. Further, in the conventional organic silver compound of the above (Chemical Formula 3), there is a possibility that impurities such as phosphorus may be mixed into the prepared silver thin film.

[0008]

In view of the above, the present inventors have found that, when producing a silver thin film by other MOCVD methods including the thermal CVD method, the present inventors have excellent thermal stability during vaporization and a high vaporization rate. As a result of conducting research to find a vapor deposition material for forming a uniform silver thin film, the above general formula (Formula 1) (wherein
In the formula, R1 to R4 are each composed of one or more linear or branched alkyl groups having 1 to 4 carbon atoms.)
When the organic silver compound represented by the formula is used as a vapor deposition raw material,
Research results have shown that it is possible to obtain a stable vaporization rate and to show excellent volatility and thermal stability.

The present invention has been made based on the above research results, and is characterized by an organic silver compound for forming a silver thin film formed by a high vapor pressure metalorganic chemical vapor deposition represented by the above general formula (Chemical Formula 1). It has.

[0010]

EXAMPLES Next, the organic silver compound of the present invention will be specifically described with reference to Examples. In a dry, nitrogen-substituted three-necked flask, 11.2 g of tert-butylacetylene and 0.0
4 ml of a 1 molar aqueous solution of chloroplatinic acid was added and stirred at 50 ° C. 44.0 g of trichlorosilane from the dropping funnel
Was slowly added dropwise and stirred vigorously. After the completion of the reaction, the solution turned black, and the solution was purified by distillation under reduced pressure (boiling point: 60 to 65 ° C./20 torr).
trans-[(1-trichlorosilyl) -3,3-dimethyl-1-butene] (hereinafter abbreviated as TCSDME)
0.0 g was obtained. This TCSDME was slowly dropped into 460 ml of an ether solution of methylmagnesium iodide at a 1.0 molar concentration in an ice bath, and after the completion of the dropping, the mixture was heated to reflux. 1
After hydrolysis with 50 ml of a saturated aqueous solution of ammonium chloride, the organic layer was extracted. The aqueous layer was extracted twice with 100 ml of ether and combined with the previous organic layer. After drying over anhydrous sodium sulfate and concentration under reduced pressure at 30 ° C, the remaining oil was purified by simple distillation (boiling point 68-70 ° C / 60 ° C).
torr), trans-[(1-trimethylsilyl)
-3,3-dimethyl-1-butene] (hereinafter TMSDME
10.0 g was synthesized.

The TMSDME of the ligand obtained was identified by NMR: 1H-NMR (CDCL3); δ0.0
42 (s, 9H), 0.987 (s, 9H), 5.50
1 (d, 1H, J = 19.05 Hz), 6.010
(D, 1H, J = 19.05 Hz).

Subsequently, 170 ml of dry methylene chloride sufficiently deaerated with nitrogen was poured into 14.8 g of silver oxide to obtain a suspension solution. 10.0 g of the above TMSDME
Is added with vigorous stirring, and 1,1,1,5,
5,5-hexafluoro-2,4-pentanedione 1
3.3 g was dropped from the dropping funnel drop by drop. After stirring the reaction system for 4 hours, the mixture was filtered under a nitrogen stream, and the filtrate was heated at 35 ° C.
Evaporation under reduced pressure gave a white solid. Purification was performed by column chromatography, and 24.2 g of the present organic silver compound represented by the following (Chemical Formula 4) as a white powder was synthesized.

[0013]

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The organic silver compound 1 of the present invention comprises trans
-[(1-trimethylsilyl) -3,3-dimethyl-1
-Butene] (1,1,1,5,5,5-hexafluoro-2,4-pentanedionato) silver (I) [hereinafter (TMS
DME) (hfac) Ag] and has a melting point of 5
It is around 5-60 ° C. Obtained Organic Silver Compound 1 of the Present Invention
Was identified by NMR and elemental analysis: 1H
-NMR (CDCL3); δ 0.23 (s, 9H),
1.19 (s, 9H), 5.46 (d, 1H, J = 1
8.3 Hz), 5.87 (s, 1H), 6.40 (d,
1H, J = 18.3 Hz). Elemental analysis; Ag amount 22.5
% (Theoretical 22.9%).

For the purpose of comparison, the conventional organic silver compounds represented by the above (Chemical Formula 2) and (Chemical Formula 3) were used under the same conditions except that 1,5-COD and trimethylphosphine were used instead of the above TMSDME. 1 and 2 were synthesized respectively. For the purpose of evaluating the vaporization characteristics of the organic silver compound of the present invention (Chem. 4) and the conventional organic silver compound 1 (Chem. 2) obtained as a result, a thermogravimetric curve (heating rate 10 ° C. /
min, nitrogen atmosphere) are shown in FIGS. 2 and 3, respectively.

Next, using the organic silver compound of the present invention represented by the above (Chemical Formula 4) and the conventional organic silver compounds 1 and 2 represented by the above (Chemical Formula 2) and (Chemical Formula 3), FIG. By thermal CVD method, a substrate: a substrate in which 100 nm of Ti is deposited on a 25 mm square Si substrate by a sputtering method, a substrate temperature: 250 ° C., a vaporization temperature: 70 ° C., a pressure: 2 torr, a flow rate of a carrier gas: 100 ccm of Ar, The silver thin film was manufactured under the conditions described in the above, and the film thickness was measured every 10 minutes. The film thickness is the section SE of the film
It was measured from the M image. The measurement results are shown in Table 1.

[0017]

[Table 1]

[0018]

According to the results shown in FIGS. 2 and 3, the organic silver compound of the present invention can be completely vaporized at a temperature from room temperature to about 200 ° C., whereas the organic silver compound of the prior art has been completely vaporized. In this case, about 30% of the residue was generated, indicating that the organic silver compound of the present invention has excellent thermal stability during vaporization.

From Table 1, it can be seen that the thickness of the organic silver compound of the present invention increases at a substantially constant rate with respect to the film formation time, and the film formation rate is higher than that of the conventional organic silver compounds 1 and 2. On the other hand, in the case of the conventional organic silver compounds 1 and 2, it is apparent that the tendency to decrease the film formation amount becomes remarkable from the time when the film formation time exceeds 30 minutes. Further, when the organic silver compound of the present invention was used, generation of decomposed silver was not observed in the vaporization vessel of the apparatus shown in FIG. Formation was observed. From this, the organic silver compound of the present invention is vaporized at a constant rate with respect to the film forming time without being decomposed in the vaporization vessel,
It also shows that the organic silver compound is more excellent in heat stability and volatility during vaporization than conventional organic silver compounds.

As described above, the organic silver compound of the present invention is excellent in thermal stability during vaporization and has a stable vaporization rate, so that it can be used for producing a silver thin film useful as a wiring material of a semiconductor device. Can be.

[Brief description of the drawings]

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

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

FIG. 3 is a thermogravimetric curve of a conventional organic silver compound 1.

[Explanation of symbols]

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

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Katsumi Ogi 1-297 Kitabukurocho, Omiya City, Saitama Prefecture Examiner, Central Research Laboratory, Mitsui Materials Co., Ltd. Ichiyoshi Karaki (56) , A) JP-A-5-106045 (JP, A) JP-A-7-188256 (JP, A) International Publication 92/7971 (WO, A) (58) Fields investigated (Int. Cl. ⁶ , DB name ) C07F 7/02 C07F 19/00 C23C 16/18 CA (STN) REGISTRY (STN) WPIDS (STN)

Claims (1)

(57) [Claims] [Claim 1] The following general formula (Chemical formula 1) (However, in the above formula, R1 to R4 are each composed of one or more of a linear or branched alkyl group having 1 to 4 carbon atoms, and R5 and R6 are each independently a C1 to C8 alkyl group. (Composed of linear and branched fluorinated alkyl groups) having a high vapor pressure for forming a silver thin film by metal organic chemical vapor deposition.