JPH07188256A - Organosilver compound for silver thin film formation by organometallic chemical vacuum deposition with high vapor pressure - Google Patents

Abstract

PURPOSE:To obtain the subject new compound presenting stable vaporization rate and excellent in the thermal stability when vaporized, thus useful as a film-forming material by organometallic chemical vacuum deposition with high vapor pressure. CONSTITUTION:This compound is expressed by formula I (R1-R4 are each a 1-4C straight chain or branched alkyl), e.g. [(l-dimethylethylsilyl)-3,3-dimethyl-1- butyne] (1,1,1,5,5,5-hexaf1uoro-2,4-pentanedionato)silver(I). This compound of formula I can be obtained, for example, by the following processes: a hexane solution of butyllithium and dimethylethylchlorosilane are successively dripped to t-butylacetylene in anhydrous THF to carry out reaction, and the resultant (1-dimethylethylsilyl)-3,3-dimethyl-1-butyne of formula II is added to a methylene chloride solution of silver oxide followed by dripping 1,1,1,5,5,5-hexafluoro-2,4- pentanedione into the above solution to carry out reaction.

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-mentioned various silver thin films by MOCVD, as a vapor deposition material, for example,

[0003]

[Chemical 2]

Represented by (1,5-cyclooctadiene)
(1,1,1,5,5,5-hexafluoro-2,4-
Pentane dionato) silver (I) [hereinafter (1,5-cod)
Abbreviated as Ag (hfac)] and the following (Chemical formula 3)

[0005]

[Chemical 3]

Is represented by (trimethylphosphine) (1,
1,1,5,5,5-hexafluoro-2,4-pentanedionato) silver (I) [hereinafter (Me3P) Ag (hfa
It is well known that an organic silver compound etc. consisting of [abbreviated as c)] is used. In addition, the silver thin film is formed in the reaction furnace 7 as shown in the schematic explanatory view of FIG.
A substrate 5 is placed on a heater 6 provided inside, and a vapor deposition material 1 made of an organic silver compound in a vaporization vessel 2 is vaporized in a heating furnace 3 provided so as to be connected to the substrate 5.
It is also known that it is formed by a thermal decomposition type MOCVD (hereinafter abbreviated as thermal CVD) method, which comprises diffusing into the reaction furnace 7 with a carrier gas 4 such as r and depositing decomposed silver on the heating substrate 5. Has been.

[0007]

However, the above-mentioned thermal CV
The conventional organic silver compounds of (Chemical formula 2) and (Chemical formula 3) used as vapor deposition raw materials in the method D are extremely unstable with respect to the heating temperature at the time of vaporization, and the above-mentioned FIG. In the inside vaporization container 3, there is a problem in the thermal stability of the compound such that the organic silver compound mostly undergoes a thermal decomposition reaction in addition to the vaporization. Further, in the conventional organic silver compound of the above (Chemical formula 3), impurities such as phosphorus may be mixed in the produced silver thin 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 acetylene derivative of a ligand was obtained. Since it has a silane compound on one side centering on a triple bond and an alkyl group on the other side, 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). In addition, the research results showing that it exhibits excellent volatility and thermal stability.

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 above 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. Dry, nitrogen-degassed anhydrous tetrahydrofuran 50 degassed with nitrogen gas in a three-necked flask
0 ml and 34.4 g of tert-butyl acetylene were put and it cooled at 0 degreeC. 250 ml of a 1.63 molar butyllithium hexane solution was slowly added dropwise from the dropping funnel and vigorously stirred. At -30 ° C, 56.7 g of dimethylethylchlorosilane 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, 150
It was hydrolyzed with ml of saturated aqueous ammonium chloride solution. The reaction solution was separated into two layers, and the organic layer was extracted. The aqueous layer was extracted twice with 100 ml ether and combined with the previous organic layer. After drying over anhydrous sodium sulfate and concentration under reduced pressure at 60 ° C., the residual oily substance was purified by simple distillation (boiling point 34 ° C./20 torr) and represented by the following (Chemical Formula 4) (1-dimethylethylsilyl) -3. , 3-dimethyl-1
52.0 g of butyne (hereinafter abbreviated as BDMESA) was synthesized.

[0011]

[Chemical 4]

The organosilicon compound of the obtained ligand is NM
Identified by R: 1H-NMR (CDCL3); δ
0.92 (s, 6H), 0.54 (q, 2H, J = 7.
81 Hz), 0.972 (t, 3H, J = 7.81H
z), 1.22 (s, 9H). 13C-NMR (CDC
L3); δ-1.82, 7.37, 8.50, 28.1.
5, 31.19, 80.59, 116.03.

Subsequently, 300 ml of dry methylene chloride which had been sufficiently deaerated with nitrogen was poured into 34.8 g of silver oxide to prepare a suspension solution. 52.0 g of the above BDMESA
Is added with vigorous stirring, and 1,1,1,5 is further added.
1,5-hexafluoro-2,4-pentanedione
Each drop was dropped from a dropping funnel. The reaction system was stirred for 4 hours and then filtered under a nitrogen stream, and the filtrate was evaporated under reduced pressure at 35 ° C. to obtain a white solid. Purification was carried out by column chromatography, and 24.0 g of an organic silver compound 1 of the present invention represented by the following (Chemical Formula 5) which was a white powder was synthesized.

[0014]

[Chemical 5]

The above-mentioned organic silver compound 1 of the present invention is [(1-dimethylethylsilyl) -3,3-dimethyl-1-butyne] (1,1,1,5,5,5-hexafluoro-2,
4-pentanedionato) silver (I) [below (BDMES
A) (hfac) Ag] and has a melting point of 27-
It is around 30 ° C. The obtained organic silver compound 1 of the present invention was identified by NMR and elemental analysis: 1H-N
MR (CDCL3); δ 0.28 (s, 6H), 0.7
2 (q, 2H, J = 7.81 Hz), 1.03 (t, 3
H, J = 7.81 Hz), 1.40 (s, 9H), 5.
88 (s, 1H). Elemental analysis; Ag amount 22.1% (theoretical value 22.3%).

Further, the ligand (1-trimethylsilyl) -3, under the same conditions except that chlorotrimethylsilane is used in place of the above dimethylethylchlorosilane.
After synthesizing 3-dimethyl-1-butyne (hereinafter abbreviated as BTMSA), 21.0 g of the inventive organic silver compound 2 represented by the following (Chemical Formula 6) was synthesized.

[0017]

[Chemical 6]

The organic silver compound 2 of the present invention is [(1-trimethylsilyl) -3,3-dimethyl-1-butyne].
(1,1,1,5,5,5-hexafluoro-2,4-
Pentane dionato) silver (I) [below (BTMSA) (h
fac) Ag.], and the obtained organic silver compound was identified by elemental analysis: elemental analysis; Ag amount 23.0% (theoretical value 22.7%).

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

Next, the organic silver compounds 1 and 2 of the present invention represented by the above (Chemical Formula 5) and (Chemical Formula 6) and the conventional organic silver compounds 1 and 2 represented by the above (Chemical Formula 2) and (Chemical Formula 3) are used. Using the thermal CVD method shown in FIG. 1, the substrate: 25 m
Substrate in which Ti is vapor-deposited on 100 m square Si substrate by 100 nm sputtering method, substrate temperature: 250 ° C., vaporization temperature: 60 ° C., pressure: 2 torr, carrier gas flow rate: 100 ccm Ar, and a silver thin film is produced. 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.

[0021]

[Table 1]

[0022]

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, in the organic silver compounds 1 and 2 of the present invention, the film thickness increased at a substantially constant rate with respect to the film formation time, and the film formation rate was the same as that of the conventional organic silver compounds 1 and 2. Compared with the case, it is faster than the conventional organic silver compound 1
In the cases of 2 and 2, it is clear that the tendency of decrease in the film formation amount becomes remarkable from the time when the film formation time exceeds 30 minutes. Further, when the organic silver compounds 1 and 2 of the present invention were used, no generation of decomposed silver was observed in the vaporization vessel of the apparatus shown in FIG. 1, while the conventional organic silver compounds 1 and 2 were used. Formation of decomposed silver 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 wiring material and the like.

[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

Claims (1)

[Claims] 1. The following general formula (Formula 1): (Wherein, R1 to R4 in the above formulas are composed of one or two or more of linear and branched alkyl groups having 1 to 4 carbon atoms) and having a high vapor pressure. Organic silver compound for thin film formation.