JP3932874B2 - Ruthenium compound for metal organic chemical vapor deposition and ruthenium-containing thin film obtained by the compound - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ruthenium compound suitable for metal organic chemical vapor deposition and a ruthenium-containing thin film obtained from the compound. More specifically, the present invention relates to a ruthenium compound that is optimal for a metal organic chemical vapor deposition method using a solid sublimation method, and a ruthenium-containing thin film obtained from the compound.
[0002]
[Prior art]
Dynamic Random Access Memory (DRAM) used as the main memory of personal computers and workstations is rapidly becoming highly integrated, and technological development of dielectric materials and electrode materials that can support high integration is thriving.
In order to impart predetermined dielectric properties to the dielectric material, a crystallization heat treatment in an oxidizing atmosphere is essential. Conventionally, polysilicon, tungsten, titanium nitride, etc. have been used as the material of the electrode laminated with the dielectric, but the electrode is oxidized when subjected to high-temperature heat treatment in an oxygen atmosphere, so there is a problem with the heat resistance of the electrode. was there. Therefore, attention is paid to Pt which has a high melting point and hardly reacts with oxygen, and Ru, RuO ₂ , Ir, and IrO ₂ that have electrical conductivity even when oxidized. A sputtering method is widely used as a method for forming Ru or RuO ₂ , but metal organic chemical vapor deposition (Metal Organic Chemical Vapor Deposition) is required for the fine processing required for further high integration. Hereinafter, it is referred to as MOCVD method).
[0003]
As an MOCVD material using Ru, a cyclopentadiene-based biscyclopentadienyl ruthenium complex (hereinafter referred to as Ru (Cp) ₂ ) or a bisethylcyclopentadienyl ruthenium complex (hereinafter referred to as Ru (EtCp) ₂ ). Β-diketone tris 2,2,6,6 tetramethyl 3,5 heptadionate ruthenium complex (hereinafter referred to as Ru (DPM) ₃ ) and the like are used.
Of these, Ru (DPM) ₃ has a lower vapor pressure than Ru (Cp) ₂ and Ru (EtCp) _2, and therefore is less frequently used as a MOCVD raw material. In addition, since Ru (EtCp) ₂ exists as a liquid near room temperature, a conventional film forming apparatus can be used, and the flow rate can be controlled by a conventional mass flow controller, so that the supply of raw materials can be stabilized. is there. However, there is a problem that it is unstable to air and difficult to handle. Since Ru (Cp) ₂ exists as a solid near room temperature and hardly dissolves in an organic solvent, the supply to the film formation chamber must be relied on by a sublimation method. However, it has the advantage of being stable to air and easy to handle.
[0004]
Studies on film formation by MOCVD using Ru (Cp) ₂ are described in Thin Solid Films 287 (1996) P. 74-79 (PCLiao et al.), Jpn. J. Appl. Physics, 38 (1999) 2194-2199. (Aoyama et al.) And 47th JSAP Scientific Lecture Proceedings P515 (Kadoshima et al.). According to these, a Ru or RuO ₂ film is formed by MOCVD using a solid sublimation method to obtain a film having excellent characteristics.
[0005]
[Problems to be solved by the invention]
However, the research report on the film formation by the MOCVD method using Ru (Cp) ₂ described above focuses on evaluating the characteristics of the formed Ru and RuO ₂ films. ) There is no description about the influence of the film formation rate and the reproducibility of the film formation rate on the particle size of ₂ .
[0006]
An object of the present invention is to provide a ruthenium compound for metal organic chemical vapor deposition capable of controlling the deposition rate and the reproducibility of the film deposition rate by metal organic chemical vapor deposition using solid sublimation, and a ruthenium-containing thin film obtained by the compound Is to provide.
[0007]
[Means for Solving the Problems ]
The invention according to claim 1 is a ruthenium compound comprising Ru (Cp) ₂ , wherein the compound has a particle size of 0.09 to 0.12 mm and an average particle size of 0.1 mm and a particle size of 1 It is a ruthenium compound for metal organic chemical vapor deposition which is a compound in which a ruthenium compound having an average particle diameter of 2.0 to 2.5 mm is mixed in a ratio of 2 to 8: 8 to 2.
In the invention according to claim 1 , a compound having a particle size range in which the reproducibility is moderate but the film forming speed is particularly excellent, and a particle size range in which the film forming speed is moderate but the reproducibility of the film forming speed is particularly excellent. By mixing the above compound at the predetermined ratio, a compound having both advantages is obtained.
[0008]
The invention according to claim 2 is a ruthenium-containing thin film formed by the MOCVD method using the solid sublimation method using the ruthenium compound according to claim 1 as a raw material .
In the invention according to claim 2, since the raw material can be stably supplied to the MOCVD apparatus by using the ruthenium compound according to claim 1, the film thickness of the formed ruthenium-containing thin film is always made uniform. Things are obtained.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
The ruthenium compound of the present invention uses Ru (Cp) ₂ as a raw material used in the MOCVD method, and Ru (Cp) ₂ which has been problematic in terms of stability and stability in order to obtain the optimum deposition rate and reproducibility of the deposition rate. ) To optimize the particle size of ₂ .
[0010]
A characteristic configuration of the present invention is a ruthenium compound made of Ru (Cp) ₂ , which has a particle size of 0.09 to 0.12 mm and an average particle size of 0.1 mm and a particle size of 1.5. It is a compound in which a ruthenium compound having an average particle diameter of 2.0 mm is mixed at a ratio of 2-8: 8-2 . When the ruthenium-containing thin film is formed by the MOCVD method using the solid sublimation method using this ruthenium compound by controlling the particle diameter within the above numerical range, the film formation rate and the reproducibility of the film formation rate are excellent.
Here, the particle diameter of the ruthenium compound of the present invention is an average value of the major axis length and the minor axis length when Ru (Cp) ₂ is observed with an optical microscope.
[0011]
As a method for controlling the particle diameter within a predetermined numerical range, for example, when controlling the particle diameter of the ruthenium compound to 0.02 to 5 mm, first, a first mesh having a size that allows particles having a particle diameter of less than 5 mm to pass through. The ruthenium compound is passed through one sieve to remove particles larger than 5 mm that do not pass through the sieve, and then the second sieve having a sieve having a size that allows particles smaller than 0.02 mm to pass through is passed through the second sieve. It is obtained by passing a ruthenium compound that has passed through one sieve and removing particles less than 0.02 mm that have passed through the second sieve.
[0012]
In addition, a ruthenium compound having a particle size of 0.09 to 0.12 mm and an average particle size of 0.1 mm has a reproducibility of the film formation rate, but the film formation rate is particularly excellent. A ruthenium compound having an average particle diameter of 2.5 mm and 2.5 mm has a particularly good reproducibility of the film forming speed although the film forming speed is moderate. A compound obtained by mixing two kinds of ruthenium compounds having different particle diameters and average particle diameters in a ratio of 2 to 8: 8 to 2 is a compound having both advantages. A preferable mixing ratio of the compound obtained by mixing is 3 to 7: 7 to 3.
[0013]
As shown in FIG. 1, the MOCVD apparatus using the solid sublimation method includes a film forming chamber 10 and the entire apparatus is covered with a heating device 11. A heater 12 is provided inside the film forming chamber 10, and a substrate 13 is held on the heater 12. The inside of the film forming chamber 10 is evacuated by a pipe 17 having a pressure gauge 14 and a needle valve 16. The heating device 11 includes a raw material tank 18 in which Ru (Cp) ₂ that is solid at room temperature is stored. A carrier gas introduction pipe 21 is connected to the raw material tank 18 through a gas flow rate control device 19, and a supply pipe 22 is connected to the raw material tank 18. The supply pipe 22 is provided with a filter 23, a needle valve 24, and a gas flow rate adjusting device 26, and the supply pipe 22 is connected to the film forming chamber 10. An oxygen gas introduction pipe 29 is connected to the film forming chamber 10 via a needle valve 27 and a gas flow rate control device 28.
[0014]
In this apparatus, the raw material tank 18 is heated to about 180 ° C. by the heating device 11 and Ru (Cp) ₂ stored in the tank 18 is gradually sublimated. Carrier gas is introduced into the raw material tank 18 from the introduction pipe 21, and Ru (Cp) ₂ sublimated in the raw material tank 18 is conveyed to the film forming chamber 10 through the supply pipe 22. Examples of the carrier gas include argon, helium, nitrogen and the like. Further, oxygen gas is supplied from the oxygen gas introduction pipe 29 into the film forming chamber 10. In the film forming chamber 10, Ru (Cp) ₂ vapor is thermally decomposed together with oxygen, and Ru or RuO ₂ generated thereby is deposited on the heated substrate 13 to form a Ru-containing thin film .
[0015]
【The invention's effect】
As mentioned above, metal-organic chemical vapor deposition for the ruthenium compound of the present invention is a ruthenium compound consisting Ru (Cp) _2, to control the particle size of this compound to a suitable particle size, particle size, average A ruthenium compound obtained by mixing two kinds of ruthenium compounds having different particle diameters in a desired ratio realizes an appropriate film formation rate and reproducibility of the film formation rate.
[Brief description of the drawings]
FIG. 1 is a schematic view of an MOCVD apparatus using a solid sublimation method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Deposition chamber 11 Heating device 12 Heater 13 Substrate 14 Pressure gauge 16 Needle valve 17 Pipe 18 Raw material tank 19 Gas flow control device 21 Carrier gas introduction pipe 22 Supply pipe 23 Filter 24 Needle valve 26 Gas flow control device 27 Needle valve 28 Gas Flow control device 29 Oxygen gas introduction pipe

Claims (2)

A ruthenium compound comprising bis (cyclopentadienyl) ruthenium,
A ruthenium compound having a particle size of 0.09 to 0.12 mm and an average particle size of 0.1 mm and a ruthenium compound having a particle size of 1.5 to 2.5 mm and an average particle size of 2.0 mm 2-8: A ruthenium compound for metal organic chemical vapor deposition which is a compound mixed at a ratio of 8-2. A ruthenium-containing thin film formed by metalorganic chemical vapor deposition using a solid sublimation method using the ruthenium compound according to claim 1 as a raw material .

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