JP2757762B2 - 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]

Embedded image

(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]

Embedded image

(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 a silver thin film is formed by other MOCVD methods including the thermal CVD method, the silver thin film has excellent thermal stability during vaporization and a high vaporization rate. to find a uniform silver thin film forming deposition material result of research, the above-mentioned general formula (formula 1) (wherein, wherein R1 is Ri consists linear and branched alkyl groups having 1 to 4 carbon atoms, When an organic silver compound represented by R2 and R3 each independently comprising a linear or branched fluorinated alkyl group having 1 to 8 carbon atoms) is used as a vapor deposition raw material, the above-mentioned (Chemical Formula 2) and (Chemical Formula 3) Research results have shown that it is possible to obtain a more stable vaporization rate than the conventional organic silver compound of (1), and it shows 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. 150 ml of dry methylene chloride sufficiently deaerated with nitrogen was poured into 13.0 g of silver oxide to obtain a suspension solution. 4.66 g of tert-butyl isocyanide are added with vigorous stirring.
11.7 g of 1,1,5,5,5-hexafluoro-2,4-pentanedione was dropped from the dropping funnel drop by drop. After stirring the reaction system for 4 hours, it was filtered under a nitrogen stream,
The filtrate was distilled off under reduced pressure at 35 ° C. to obtain a brown powder. The purification was performed by column chromatography, and the organic silver compound of the present invention represented by the following (Chemical Formula 4), which was a white powder, was purified by one step.
6.7 g were synthesized.

[0011]

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The organic silver compound 1 of the present invention has a (tert)
-Butyl isocyanide) (1,1,1,5,5,5-
Hexafluoro-2,4-pentanedionato) silver (I)
Consists of The obtained organic silver compound 1 of the present invention was identified by N
Performed by MR and elemental analysis: 1H-NMR (C
DCL3); δ 1.53 (s, 9H), 5.84 (s,
1H). Elemental analysis; Ag content 27.5% (theoretical value 27.1)
%).

Also, for the purpose of comparison, the above-mentioned (Chemical Formula 2) and (Chemical Formula 3) were used under the same conditions except that 1,5-COD and trimethylphosphine were used in place of the above tert-butyl isocyanide. Conventional organic silver compound 1
And 2 were synthesized respectively.

Next, using the organic silver compound of the present invention represented by the above-mentioned (Chemical Formula 4) and the conventional organic silver compounds 1 and 2 represented by the above-mentioned (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 carrier gas flow rate: 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 was measured from a cross-sectional SEM image of the film. The measurement results are shown in Table 1.

[0015]

[Table 1]

[0016]

As can be seen from Table 1, the thickness of the organic silver compound of the present invention increases at a substantially constant rate with respect to the film forming time, and the film forming speed 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. Thus, the organic silver compound of the present invention is vaporized at a constant rate with respect to the film formation time without being decomposed in the vaporization vessel, and is more excellent in heat stability and volatility during vaporization than conventional organic silver compounds. This indicates that it is a silver compound.

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 for semiconductor devices. Can be.

[Brief description of the drawings]

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

[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

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C07F 1/10 C23C 16/18 CA (STN) CAOLD (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] [Claim 1] The following general formula (Formula 1) (Wherein R1 is a straight-chain and branched alkyl group having 1 to 4 carbon atoms, and R2 and R3 are each independently a straight-chain and branched fluorinated alkyl group having 1 to 8 carbon atoms) Organic silver compound for forming a silver thin film by metalorganic chemical vapor deposition having a high vapor pressure.