JP2006183069A - Method for producing metal oxide film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a metal oxide film having excellent film deposition properties in a method of producing a metal oxide film on an object for film deposition using metal complex gas and water vapor by a chemical vapor deposition process. <P>SOLUTION: In the method of producing a metal oxide film on an object for film deposition using metal complex gas and water vapor by a chemical vapor deposition process, as the metal complex, the one with β-diketonate having silyl ether groups as a ligand is used. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a metal oxide film on a film formation target by a chemical vapor deposition method (hereinafter referred to as a CVD method) using a metal complex gas and water vapor.

  In recent years, many studies and developments have been made on metal complex compounds as materials in the fields of semiconductors, electronic components, optical components, and the like. For example, Group IVA metal compounds of the periodic table (for example, titanium, zirconium, hafnium, etc.) are used as ferroelectrics (PZT) and semiconductor memory gate insulating films.

By the way, as a method for producing a metal oxide film on a film formation target by a CVD method using a metal-containing gas and water vapor, for example, a metal oxide film using a gas of alkoxide of hafnium or zirconium and water vapor is used. A manufacturing method is known, but this method has a problem that it is difficult to control a reaction in forming a metal oxide film (see, for example, Non-Patent Document 1).
“Electronic Materials” July 2002, p. 29

Also known is a method for producing a metal oxide film by simultaneously supplying gas and water vapor using tetrakis (1-methoxy-2-methyl-2-propoxide) hafnium as raw materials. Since the hafnium complex has a high melting point, there is a risk of piping clogging in the raw material supply system in the CVD apparatus during film formation by the CVD method, which is unsuitable as a metal oxide film manufacturing raw material by the industrial CVD method. (For example, refer to Patent Document 1).
JP 2004-71757 A

An object of the present invention is to solve the above-mentioned problems in a method for producing a metal oxide film on a film formation object by chemical vapor deposition using a metal complex gas and water vapor, and excellent film formation. The present invention also provides a method for producing a metal oxide film having a property.

  An object of the present invention is to provide a β-diketonato having a silyl ether group as a metal complex in a method for producing a metal oxide film on a film formation object by chemical vapor deposition using a metal complex gas and water vapor. It solves by the manufacturing method of a metal oxide film characterized by using the metal complex which uses as a ligand.

  According to the present invention, there is provided a method for producing a metal oxide film having excellent film formability in a method for producing a metal oxide film on an object to be formed by chemical vapor deposition using a metal complex gas and water vapor. I can do it.

  The metal complex having the β-diketonato group of the present invention as a ligand is represented by the above general formula (I)

Indicated by In the general formula (I), M is a metal atom, preferably a metal atom of Group IVA of the periodic table, more preferably a hafnium atom, a zirconium atom or a titanium atom. X represents the general formula (II)

R ^a is a straight chain or branched chain having 1 to 5 carbon atoms such as methylene group, ethylene group, trimethylene group, propylene group, dimethylmethylene group, tetramethylene group, ethylethylene group, pentamethylene group, etc. -Like alkylene group, R ^b , R ^c and R ^d have 1 carbon atom such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, pentyl group, etc. And Y represents a group represented by the general formula (II), or a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group. , An isobutyl group, a t-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, etc., a linear or branched alkyl group having 1 to 8 carbon atoms, Z is a hydrogen atom or a methyl group, ethyl Group, n-propyl group, isopropyl group , N- butyl group, an isobutyl group, a straight-chain or branched alkyl group having 1 to 4 carbon atoms a t- butyl group and the like. n shows the integer of 2-4.

The β-diketone that is the basis of the β-diketonato group (ligand) of the metal complex of the present invention is a compound that can be easily synthesized by a known method (for example, see Patent Document 2).
International Patent No. 03/064437 Pamphlet

  Specific examples of the metal complex having a β-diketonato group as a ligand of the present invention are represented by, for example, formulas (III) to (XI).

  In the CVD method, it is necessary to vaporize a metal complex for forming a thin film. As a method for vaporizing a metal complex having a β-diketonato group as a ligand of the present invention, for example, the metal complex itself is used. In addition to the method of vaporizing by filling or transporting into the vaporization chamber, the metal complex is converted into an appropriate solvent (for example, aliphatic hydrocarbons such as hexane, octane, methylcyclohexane, and ethylcyclohexane; aromatic hydrocarbons such as toluene; Examples include tetrahydropyran, ethers such as dibutyl ether, etc.). A method (solution method) in which a solution diluted with a liquid transport pump is introduced into a vaporization chamber and vaporized.

  As a vapor deposition method of the metal oxide on the film formation target, it can be performed by a known CVD method, for example, on a film formation target heated with a metal complex gas together with water vapor under normal pressure or reduced pressure. It is possible to use a method of feeding and depositing a metal oxide film.

  In the case of depositing a metal oxide film using a metal complex having a β-diketonate having a silyl ether group of the present invention as a ligand (for example, a metal complex having a metal atom of Group IVA of the periodic table as a central metal), As the deposition conditions, for example, the reaction system internal pressure is preferably 1 to 200 kPa, more preferably 10 to 110 kPa, and the film formation target temperature is preferably 50 to 700 ° C., more preferably 100 to 500 ° C., metal The temperature for vaporizing the complex is preferably 50 to 250 ° C, more preferably 90 to 200 ° C.

  In addition, as a content rate of water vapor | steam with respect to the total gas amount at the time of vapor-depositing a metal oxide film, Preferably it is 5-90 volume%, More preferably, it is 10-70 volume%.

  Next, the present invention will be specifically described with reference to examples, but the scope of the present invention is not limited thereto.

Reference Example 1 (Synthesis of 2,6-dimethyl-2-trimethylsilyloxy-3,5-heptanedione (hereinafter referred to as sopd))
Sodium amide 13.7 g (0.351 mol) and hexane 200 ml were added to a 500 ml flask equipped with a stirrer, thermometer and dropping funnel, and 26.7 g (0.140) of methyl 2-trimethylsilyloxy-2-methylpropionate while stirring. mol) was added dropwise. Next, 12.1 g (0.141 mol) of 3-methyl-2-butanone was added dropwise with stirring, and the mixture was reacted at 15 ° C. for 1 hour. After completion of the reaction, acetic acid was added to make it weakly acidic, and the organic layer was washed with water and dried over anhydrous sodium sulfate. After filtration, the filtrate was distilled under reduced pressure (101 ° C., 1067 Pa) to obtain 18.8 g of 2,6-dimethyl-2-trimethylsilyloxy-3,5-heptanedione (isolation yield: 55%).
The physical properties of 2,6-dimethyl-2-trimethylsilyloxy-3,5-heptanedione were as follows.

¹ H-NMR (CDCl ₃ , δ (ppm)); 1.14 (6H, d), 1.39 (6H, s), 2.44 to 2.50 (0.85H, m), 2.64 to 2.69 (0.15H, m), 3.77 ( 0.3H, s), 5.97 (0.85H, s), 15.51 (0.85H, s)
IR (neat (cm ^-1 )); 2971, 1606 (br), 1253, 1199, 1045, 842
(The peak at 1606 cm ^{-1 is} a peak peculiar to β-diketone.)
MS (m / e); 244

Reference Example 2 (Synthesis of tetrakis (2,6-dimethyl-2-trimethylsilyloxy-3,5-heptanedionato) hafnium (IV) (hereinafter referred to as Hf (sopd) ₄ ))
Into a 50 ml flask equipped with a stirrer, thermometer and dropping funnel was added 1.60 g (4.46 mmol) hafnium tetraethoxide and 23.1 g (5.50) 2,6-dimethyl-2-trimethylsilyloxy-3,5-heptanedione. mmol) was added and reacted at 220 ° C. for 2 hours. After completion of the reaction, the reaction solution was concentrated under reduced pressure, and 80 ml of hexane was added to the concentrate. After filtration, the filtrate was washed with water, dried and concentrated, and the concentrate was distilled under reduced pressure (240 ° C., 67 Pa) to give tetrakis (2,6-dimethyl-2-trimethylsilyloxy-3,5-heptanedionate as a pale yellow solid. ) 3.00 g of hafnium (IV) was obtained (isolation yield: 58%).
The physical properties of tetrakis (2,6-dimethyl-2-trimethylsilyloxy-3,5-heptanedionato) hafnium (IV) were as follows.

IR (neat (cm ^-1 )); 2967, 1586, 1540, 1509, 1440, 1252, 1199, 1047, 892, 841
(The peak peculiar to β-diketone (1606cm ^-1 ) disappeared and the peak peculiar to β-diketonato (1586cm ^-1 ) was observed.)
Elemental analysis (C ₄₈ H ₉₂ O ₁₂ Si ₄ Hf); carbon: 50.3%, hydrogen: 8.10%, hafnium: 15.5%
(Theoretical value: Carbon: 50.0%, Hydrogen: 8.05%, Hafnium: 15.5%)
MS (m / e); 998, 909, 131, 73

Examples 1-2 (deposition experiment; production of metal oxide film)
Using the metal complex obtained in Reference Example 2 (hafnium complex (Hf (sopd) ₄ )), a vapor deposition experiment by a CVD method was performed to evaluate the film formation characteristics.
The apparatus shown in FIG. 1 was used for the evaluation test. The metal complex 20 in the vaporizer 3 (glass ampoule) is heated and vaporized by the heater 10B, exits the vaporizer 3 along with the helium gas introduced after preheating by the preheater 10A via the mass flow controller 1A. The gas exiting the vaporizer 3 is introduced into the reactor 4 together with water vapor introduced through the mass flow controller 1B and cooled water (2 ° C.) 8. Further, hydrogen gas or helium gas may be introduced into the reaction system via the mass controller 1C. The pressure in the reaction system is controlled to a predetermined pressure by opening and closing the valve 6 in front of the vacuum pump, and is monitored by the pressure gauge 5. The central part of the glass reactor has a structure that can be heated by the heater 10C. The metal complex introduced into the reactor is set at the center of the reactor and is oxidized and pyrolyzed on the surface of the deposition substrate 21 heated to a predetermined temperature by the heater 10C. A metal oxide film is formed on the substrate 21. Precipitate. The gas exiting the reactor 4 is exhausted to the atmosphere via a trap 7 and a vacuum pump.

  The deposition conditions and deposition results (film characteristics) are shown in Table 1. Note that a 7 mm × 40 mm rectangular substrate was used as the deposition base.

From the results, it is possible to produce a metal oxide film having excellent film formability using a metal complex (hafnium complex (Hf (sopd) ₄ ) gas and water vapor.

  The present invention relates to a method for producing a metal oxide film on a film formation target by a CVD method using a metal complex gas and water vapor.

It is a figure which shows the structure of a vapor deposition apparatus.

Explanation of symbols

3 Vaporizer 4 Reactor 9 Cooler 10 B Vaporizer heater 10 C Reactor heater 20 Raw material metal complex melt 21 Substrate

Claims (5)

  In a method for producing a metal oxide film on an object to be deposited by chemical vapor deposition using a metal complex gas and water vapor, a β-diketonate having a silyl ether group is used as a ligand as a metal complex. A method for producing a metal oxide film, comprising using a metal complex. A metal complex having a β-diketonate having a silyl ether group as a ligand is represented by the general formula (I)

(In the formula, M represents a metal atom. X represents the general formula (II).

Wherein R ^a is a linear or branched alkylene group having 1 to 5 carbon atoms, and R ^b , R ^c and R ^d are linear or branched groups having 1 to 5 carbon atoms. And Y represents a group represented by the general formula (II) or a linear or branched alkyl group having 1 to 8 carbon atoms, and Z represents a hydrogen atom or 1 carbon atom. -4 alkyl groups are shown. n shows the integer of 1-4. )
The manufacturing method of the metal oxide film of Claim 1 which is a metal complex shown by these.   The method for producing a metal oxide film according to claim 2, wherein the metal atom is a metal atom of Group IVA of the periodic table.   The method for producing a metal oxide film according to claim 2, wherein the solvent solution of the metal complex according to claim 2 is used as a metal supply source.   The method for producing a metal oxide film according to claim 4, wherein the solvent is at least one solvent selected from the group consisting of aliphatic hydrocarbons, aromatic hydrocarbons, and ethers.

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