JPH07133285A - Organosilver compound for forming thin film of silver by organometallic chemical deposition having high vapor pressure - Google Patents

Abstract

PURPOSE:To obtain the subject compound useful for producing a thin film of silver suitable as a contact of a semiconductor device, etc., having excellent thermal stability and volatility in vaporization, comprising a specific compound. CONSTITUTION:This organosilver compound for forming thin film of silver by organometalllc chemical deposition having high vapor pressure comprises a compound of the formula (R<1> and R<6> are each a 1-4C alkyl or H) such as [trans-1,2-(bistrimethylsilyl)-ethene] (1,1,1,5,5,5-hexafluoro-2,4-pentanedionate)silver(I).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to metal organic chemical vapor deposition (hereinafter referred to as "M") of silver thin films such as contacts and wirings of semiconductor devices.
The present invention relates to an organic silver compound suitable for use as a vapor deposition material when it is formed by the OCVD method.

[0002]

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

[0003]

[Chemical 2]

(1,5-cyclooctadiene) (1,1,1,5,5,5-hexafluoro-2, represented by
4-pentanedionato) silver (I) (cyclooctadiene; hereinafter abbreviated as COD) and the following (chemical formula 3)

[0005]

[Chemical 3]

Represented by (trimethylphosphine)
(1,1,1,5,5,5-hexafluoro-2,4-
It is well known that an organic silver compound consisting of pentanedionato) silver (I) is used. Also,
The silver thin film has a substrate 5 placed on a heater 6 provided in a reaction furnace 7 as shown in a schematic explanatory view of FIG. 1, for example.
On the other hand, in a heating furnace 3 connected to this, the vapor deposition material 1 made of an organic silver compound in the vaporization vessel 2 is vaporized, and this is diffused into the reaction furnace 7 by a carrier gas 4 such as Ar, It is also known to be formed by a thermal decomposition type MOCVD (hereinafter abbreviated as thermal CVD) method, which comprises depositing decomposed silver on the heating substrate 5.

[0007]

However, the above-mentioned thermal CV
The conventional organic silver compound of (Chemical Formula 2) used as a vapor deposition raw material in the method D is extremely unstable with respect to the heating temperature at the time of vaporization, and the vaporization container 3 shown in FIG. In addition to vaporization, there is a problem in the thermal stability of the compound, such that most of the organic silver compounds undergo a thermal decomposition reaction. Further, the conventional organic silver compound of (Chemical formula 3) is superior in thermal stability to the conventional organic silver compound of (Chemical formula 2), but there is a possibility that impurities such as phosphorus may be mixed in the produced silver film. .

[0008]

From the above viewpoints, the inventors of the present invention have a uniform vaporization rate when producing a silver thin film by the other MOCVD methods including the thermal CVD method, and the thermal stability at the time of vaporization. As a result of research to find a highly pure vapor deposition raw material for forming a silver thin film, when an organic silver compound represented by the general formula (Formula 1) was used as a vapor deposition raw material, an ethylene derivative of a ligand was obtained. Since it has a silane compound in the trans position, it is possible to obtain a more stable vaporization rate than the conventional organic silver compounds of the above (Chemical formula 2) and (Chemical formula 3), and to have excellent volatility and thermal stability. I got the research result to show.

The present invention has been made on the basis of the above-mentioned research results, and is characterized by an organic silver compound for forming a silver thin film by metal organic chemical vapor deposition having a high vapor pressure, which is represented by the general formula (Formula 1). Is to have.

[0010]

EXAMPLES Next, the organic silver compounds of the present invention will be specifically described with reference to Examples. 26.0 g of trimethylsilylacetylene and 4 ml of 10% chloroplatinic acid aqueous solution were mixed in a three-necked flask that had been dried and purged with nitrogen, and the mixture was heated to 50 ° C. 25 g of dimethylchlorosilane was slowly dropped from the dropping funnel, and the mixture was heated and stirred at 50 ° C. After completion of the reaction, purification was carried out by distillation under reduced pressure to obtain 18.3 g of trans-1- (chlorodimethylsilyl) -2- (trimethylsilyl) -ethene (boiling point 56-60 ° C / 20 torr). This compound was dissolved in 60 ml of anhydrous diethyl ether, 102 ml of an ether solution of methylmagnesium iodide having a molar concentration of 1 was slowly added dropwise in an ice bath, and the mixture was heated with stirring for 4 hours after the completion of the addition. In the ice bath again, 100 ml of saturated ammonium chloride aqueous solution was slowly added. The aqueous layer was extracted three times with ether, the organic layer and the extracted solution were combined, and the solvent was evaporated under reduced pressure. The residual oil was purified by vacuum distillation to give 10.4 g of trans-1,2-
(Bistrimethylsilyl) -ethene (hereinafter abbreviated as BTMSE) was synthesized (boiling point 85 to 90 ° C./100 torr)
r). Subsequently, 140 ml of dry methylene chloride that had been sufficiently degassed with nitrogen was poured into 12.8 g of silver oxide to prepare a suspension solution. 10.4 g of the above BTMSE was added with vigorous stirring, and further 1,1,1,5,5,5
-Hexafluoro-2,4-pentanedione 12.4 g
(Hereinafter, abbreviated as Hhfac) was added dropwise by a syringe. 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 white powder 21.0. Purification is performed by sublimation (90 ° C / 0.2to
rr), an organic silver compound 1 of the present invention represented by the following (Chemical Formula 4) which is a white powder.

[0011]

[Chemical 4]

1% of [trans-1,2- (bistrimethylsilyl) -ethene] (1,1,1,5,5,5-hexafluoro-2,4-pentanedionato) silver (I)
2.5 g was obtained. Melting point around 68-70 ° C. The obtained organic silver compound was identified by NMR and elemental analysis: 1H-NMR (CDCl3); 0.23 (s, 18
H), 5.88 (s, 2H), 6.17 (s, 1H)
.

The organic silver compound 2 of the present invention represented by the following (Chemical Formula 5) using a tetrahydrofuran solution of ethyl magnesium bromide in place of the above-described methyl magnesium iodide.

[0014]

[Chemical 5]

[Trans-1- (trimethylsilyl)]
-2- (Dimethylethylsilyl) -ethene] (1,1,
11.9 g of 1,5,5,5-hexafluoro-2,4-pentanedionato) silver (I) was obtained. Furthermore, an organic silver compound 3 of the present invention represented by the following (Chemical Formula 6) using methylchlorosilane in place of the above dimethylchlorosilane

[0016]

[Chemical 6]

[Trans-1- (trimethylsilyl)]
-2- (Dimethylsilyl) -ethene] (1,1,1,
5.3 g of 5,5,5-hexafluoro-2,4-pentanedionato) silver (I) was obtained. For the purpose of comparison, the conventional organic silver compounds 1 and 2 shown in 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 BTMSE. Were synthesized respectively.

The resulting organic silver compound 1 of the present invention (Chemical formula 4) and the conventional organic silver compound 1 of the above (Chemical formula 5) obtained as a result
Thermogravimetric curve (temperature increase rate 10
(° C / min, nitrogen atmosphere) are shown in FIGS. 2 and 3, respectively.

Then, using the organic silver compound of the present invention and the conventional organic silver compounds represented by the above (Chemical Formula 2) and (Chemical Formula 3) by the thermal CVD method shown in FIG. A substrate obtained by depositing Ti on a Si substrate by a 1000Å sputtering method, a substrate temperature: 300 ° C., a vaporization temperature: 70 ° C., a pressure: 2 torr, and a carrier gas flow rate: 100 ccm of Ar. The film thickness was measured every minute. The film thickness was measured from a cross-sectional SEM image of the film. The measurement results are shown in Table 1.

[0020]

[Table 1]

[0021]

From 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., while the conventional organic silver compound has been vaporized. In this case, about 30% of the residue was formed, which indicates that the organic silver compound of the present invention has excellent thermal stability during vaporization.

Further, from Table 1, the organic silver compound of the present invention increases in film thickness at a substantially constant rate with respect to film forming time, and the film forming rate thereof is faster than that of conventional organic silver compounds. In the case of the conventional organic silver compound, it is clear that the tendency for the amount of film formation to decrease becomes remarkable from the time when the film formation time exceeds 30 minutes. Further, in the above examples, when the organic silver compound of the present invention was used, no generation of decomposed silver was observed in the vaporization container of the apparatus shown in FIG. Generation was observed. As a result, the organic silver 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 to the conventional organic silver compounds in thermal stability and volatility during vaporization. It shows that it is a silver compound.

As described above, the organic silver compound of the present invention has a stable vaporization rate and is excellent in thermal stability during vaporization, and therefore is useful as a film-forming raw material by the MOCVD method, and is useful for semiconductor devices. It can be used for producing a silver thin film useful as a contact and wiring material.

[Brief description of drawings]

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

FIG. 2 is a thermogravimetric curve of the organic silver compound 1 of the invention.

FIG. 3 is a thermogravimetric curve of Conventional Organic Silver Compound 1.

[Explanation of symbols]

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

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[Procedure amendment]

[Submission date] December 7, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

The resulting organic silver compound 1 of the present invention of the above (Chemical formula 4) and the conventional organic silver compound 1 of the above (Chemical formula 2) obtained as a result
Thermogravimetric curve (temperature increase rate 10
(° C / min, nitrogen atmosphere) are shown in FIGS. 2 and 3, respectively.

Claims (1)

[Claims] 1. The following general formula (Formula 1): (However, R1 to R6 in the above formulas are composed of one or two or more of a linear or branched alkyl group having 1 to 4 carbon atoms and hydrogen) and high vapor pressure organometallic chemical vapor deposition. An organic silver compound for forming a silver thin film by.