TWI398445B - Raw material for forming a strontium-containing thinfilm and process for preparing the raw material - Google Patents

Description

Raw material for forming a film containing bismuth and manufacturing method thereof

The present invention relates to a method suitable for forming cerium oxide by chemical vapor growth method (Chemical Vapor Deposition method; hereinafter referred to as CVD method) or atomic layer deposition method (Atomic Layer Deposition method; hereinafter referred to as ALD method) A raw material compound of a film of barium sulfide, a method for producing the same, and a method for forming a film containing barium.

Film materials such as SrTiO ₃ , SrBi ₂ Ta ₂ O ₉ , and SrBi ₄ Ti ₄ O _{15 having a} high dielectric constant by CVD or ALD are expected to be dielectrics of high-integration semiconductor devices, and SrRuO ₃ films have been studied. As an electrode of a ferroelectric film.

In the past, the raw materials for the formation of such ruthenium-containing film materials by CVD or ALD were mainly studied as bis(dipentamethylene methane) ruthenium (Sr(C ₁₁ H ₁₉ O ₂ ) ₂ ; the following is Sr (dpm) ) ₂ to indicate).

However, since Sr(dpm) ₂ is a triad, the vapor pressure is very low at 0.1 Torr/231 ° C, and there is a problem in supply.

Further, since thermal decomposition starts when the temperature is 230 ° C or higher, when the film is formed by the ALD method, not only the desired autoradial growth but also the problem of simultaneous thermal decomposition which is difficult to control is caused.

Therefore, it is necessary to have an organic cerium compound having a higher vapor pressure and high reactivity with an oxidizing agent and high thermal stability.

For example, examples of the candidate compound include bis(pentacyclopentadienyl)fluorene (Sr[C ₅ (CH ₃ ) ₅ ] ₂ ) which is a known compound; and SrCp ^* ₂ hereinafter. Here, SrCp ^* ₂ is not an already-added adduct such as diethyl ether ((C ₂ H ₅ ) ₂ O; hereinafter referred to as Et ₂ O) or tetrahydrofuran (C ₄ H ₈ O; hereinafter referred to as THF) .

Since the above-mentioned adduct has low heat stability and emits an adduct at the same time as heating and is thermally degraded, it is impossible to form a stable vapor pressure, and since the adduct contains oxygen atoms, oxygen may be supplied by self-decomposition. It should not be used as a raw material for ALD.

On the other hand, since the SrCp ^* ₂ of the non-additive is a monomer, it is one of the highest vapor pressures among the organic ruthenium compounds, and has a property of being instantaneously reacted with water of the oxidant, which is suitable as a raw material of the ALD method, and It also has the advantage of being easily dissolved in an organic solvent by the influence of five methyl groups.

Therefore, the inventors disclosed the manufacturing method of SrCp ^* ₂ in Japanese Patent Application No. 2006-330359.

However, since SrCp ^* _{2 has} a melting point of 207 ° C and is solid at room temperature, in the above production method, it is necessary to carry out final purification by sublimation operation, and since it is deteriorated by a very small amount of oxygen and moisture. Solid, so there must be expensive equipment and careful handling when handling.

Therefore, in order to carry out distillation purification with high purification efficiency and easy treatment in an inert gas atmosphere, it is necessary to have a compound which is in a liquid state at a temperature of from room temperature to 50 °C.

That is, it is necessary to have a liquid compound which is a cyclopentadienyl ruthenium compound which is active against oxygen and moisture, and which is not added with an ether, is a monomer and has a high vapor pressure, and is easily mass-produced. The group.

However, the β-diketone ruthenium complex such as Sr(dpm) ₂ is synthesized by using a metal Sr in a raw material, but contains a few ppm of Na or K in the metal Sr, and is also contained in the crude composition. A few ppm of Na and K.

Further, a raw material such as NaC ₅ (CH ₃ ) ₅ (hereinafter referred to as NaCp ^* ) or KC ₅ (CH ₃ ) ₅ (hereinafter referred to as KCp ^* ) is used as a raw material of a cyclopentadiene-based ruthenium compound such as SrCp ^* ₂ . The metal compound is synthesized, so the crude composition contains a large amount of Na or K.

Since the β-diketone ruthenium complex and SrCp ^* ₂ are solid at a temperature close to room temperature, purification by distillation is difficult, and it is difficult to effectively remove Na or K from the raw material.

Therefore, in the raw materials for forming a film containing ruthenium, it is difficult to obtain a content of Na and K of 50 ppb or less, and it is not applicable to the content of Na and K of CVD or ALD of 50 ppb or less. A material used to form a film containing ruthenium.

Therefore, the inventors believe that in the commercially available cyclopentadiene compound, tetramethyl(n-propyl)cyclopentadiene (C ₅ (CH ₃ ) ₄ (C) having a structure similar to pentacyclopentadiene can be used. ₃ H ₇ )H) The compound to be synthesized is bis(propenylcyclopentadiene) ruthenium (Sr[C ₅ (CH ₃ ) ₄ (C ₃ H ₇ )) ₂ Sr[C ₅ (CH ₃ ) ₄ ( C ₃ H ₇ )] ₂ ; the following is preferably represented by Sr(PrMe ₄ Cp) ₂ ).

The Sr(PrMe ₄ Cp) ₂ line is disclosed in the specification of European Patent No. 1645656 and is registered as a compound of CAS No. 882296-98-2.

Further, in "MOCVD & CVD Precursors", Strem, 1999, CVD 11/99, p. 22, there is disclosed an addition of 1,2-dimethoxyethane (Sr(PrMe ₄ Cp) ₂ ). ₃ OC ₂ H ₄ OCH ₃ ; the following compound represented by DME).

However, in the specification of the aforementioned European Patent No. 1645656, it is only disclosed in the table of the seventh embodiment that the InAs film is grown at 600 ° C by MOCVD using trimethyl indium and monoethyl hydrazine as a raw material. The amount of media (<0.25 mol%) makes Sr(PrMe ₄ Cp) ₂ coexist, and Sr(PrMe ₄ Cp) ₂ is added as a trace catalyst, which does not substantially contain Sr in the film, and does not reveal about Sr at all. (PrMe ₄ Cp) ₂ method or physical property.

Further, in the above-mentioned "MOCVD & CVD Precursors", Strem, 1999, CVD 11/99, p. 22, Sr(PrMe ₄ Cp) ₂ having no ether added is also not disclosed.

The cyclopentadienyl hydrazine compound is a compound obtained by synthesizing a compound obtained by adding an ether, and then removing the ether, and it is difficult to synthesize it without using an adduct, and it is difficult to remove the added ether. easily.

Therefore, the production method or physical properties of Sr(PrMe ₄ Cp) ₂ have not been known so far, and a film containing Sr as a main component as a raw material has not been formed, and in the production method of Sr(PrMe ₄ Cp) ₂ The type of ether compound used and the method of removing ethers become important.

Further, in the material for forming the semiconductor thin film, even if only a slight amount of Na is incorporated, the electric field unevenness at the semiconductor interface or the corrosion of the conductor film greatly impairs the semiconductor characteristics, and therefore it is necessary to make Na in the organic germanium complex. The concentration is close to 0 and K must be the same.

The present invention has been completed in view of the above circumstances. The object of the invention is to provide a raw material for forming a film containing ruthenium. The raw material for forming a film containing ruthenium is liquid at room temperature to 50 ° C and can be distilled and refined, is a monomer and has a high vapor pressure, and is easily mass-produced. It is also achieved by using a cyclopentadiene ruthenium compound.

Further, it is an object of the present invention to provide a film containing ruthenium which can reduce the contents of Na and K.

Further, it is an object of the present invention to provide a process for producing the aforementioned compound.

The raw material for forming a film containing ruthenium according to the present invention is Sr(PrMe ₄ Cp) ₂ .

In the above-mentioned raw material for forming a film containing ruthenium, it is preferred that the respective contents of K and Na are 50 ppb or less.

Further, the method for producing a raw material for forming a film containing ruthenium according to the present invention is obtained by the following procedure: Sr(PrMe ₄ Cp) _{2 is obtained} by using sodium perylenetetracyclopentadiene (hereinafter, Na(PrMe _{4 )} Cp) or potassium tetramethylcyclopentadiene (hereinafter referred to as K(PrMe ₄ Cp)) is reacted with cerium iodide (SrI ₂ ) in THF to form THF of Sr(PrMe ₄ Cp) ₂ Procedure for addition; distillation to remove THF, and toluene solution by toluene extraction; distillation to remove toluene and drying under reduced pressure; and heating to 100-160 ° C under vacuum, and dissociation to remove THF The procedure for distillation is carried out.

The Sr(PrMe ₄ Cp) _{2 which} is a raw material for forming a film containing ruthenium according to the present invention is a liquid compound suitable for mass production, and can be suitably obtained by the production method of the present invention.

Further, since Sr(PrMe ₄ Cp) _{2 which} is a material for forming a film containing ruthenium according to the present invention has a high vapor pressure and a liquid at room temperature, it can be purified by distillation, and is formed to contain ruthenium. The material of the film can greatly reduce the content of Na and K which greatly affect the semiconductor characteristics.

Therefore, when Sr(PrMe ₄ Cp) ₂ obtained by the present invention is used, the film containing ruthenium can be mass-produced by CVD or ALD, and a film containing ruthenium capable of reducing Na and K contents can be formed. .

The invention is explained in more detail below.

The raw material for forming a film containing ruthenium according to the present invention is Sr(PrMe ₄ Cp) ₂ .

Sr(PrMe ₄ Cp) ₂ which is the starting material compound can be suitably obtained by the production method of the present invention.

Specifically, Sr(PrMe ₄ Cp) ₂ can be obtained by the following procedure, that is, Na(PrMe ₄ Cp) or K(PrMe ₄ Cp) is reacted with SrI ₂ in THF, and Sr(PrMe ₄ Cp) is produced. Procedure for THF addition of ₂ ; distillation of THF and extraction with toluene to prepare a toluene solution; distillation to remove toluene and drying under reduced pressure; and heating to 100-160 ° C under vacuum, and dissociation The procedure for distillation after removal of THF.

The manufacturing procedure will be described in order below.

First, Na(PrMe ₄ Cp) can be obtained by a known method such as the following method, that is, commercially available propenylcyclopentadiene (C ₅ (CH ₃ ) ₄ (C ₃ H ₇ )H; : tetramethyl (n-propyl) cyclopentadiene) (manufactured by Strem Corporation, manufactured by Alfa Aesar Co., Ltd.), a method of reacting with NaNH ₂ in liquid NH ₃ ; or a method of reacting with NaH in THF or DME.

K (PrMe ₄ Cp) can also be obtained by the same method.

Next, the Na(PrMe ₄ Cp) or K(PrMe ₄ Cp) and the anhydrous SrI _{2 obtained in the above are} dissolved in THF of a synthesis reaction solvent of Sr(PrMe ₄ Cp) ₂ , and the synthesis reaction proceeds easily. And Sr(PrMe ₄ Cp) ₂ (THF) adduct was produced.

Further, when DME is used as the synthesis reaction solvent, the Sr(PrMe ₄ Cp) ₂ (DME) adduct can be easily formed. However, as shown in the first comparative example below, DME cannot be easily removed afterwards, so DME is Not suitable.

Further, when diethyl ether is used as the solvent, the solubility of the reaction raw material is small, the reaction rate is low, and the volumetric efficiency is poor, so diethyl ether is also unsuitable.

After the completion of the synthesis reaction, the THF solvent is distilled off, and the Sr(PrMe ₄ Cp) ₂ (THF) adduct is extracted by toluene, and the adduct is sufficiently dissolved by toluene, whereas the by-product sodium iodide or Potassium iodide does not dissolve at all, so extraction is easy.

The toluene solution was distilled off from the extracted toluene solution and dried under reduced pressure to obtain an Sr(PrMe ₄ Cp) ₂ (THF) adduct having a melting point of about 130 ° C.

If the adduct is heated to 100-160 ° C under a vacuum of 0.001 to 0.1 Torr, the melt state will be formed in the autoclave, and the dissociated THF will accumulate in the cryogenic separator, if accumulated in the separator. When the increase is stopped, Sr(PrMe ₄ Cp) _{2 is} distilled off by a distillation operation at 160 to 180 ° C / 0.01 to 0.1 Torr.

The Sr(PrMe ₄ Cp) ₂ obtained in this way is a viscous liquid which does not solidify at room temperature.

When Sr(PrMe ₄ Cp) ₂ obtained by the above method is used as a raw material, an oxide film containing a ruthenium, a sulfide film, or the like can be stably formed by a CVD method or an ALD method.

Further, according to the above-described production method of the present invention, Sr(PrMe ₄ Cp) ₂ having a K and Na content of 50 ppb or less can be obtained.

Therefore, when Sr(PrMe ₄ Cp) _{2 having} a small K and Na content obtained by the production method of the present invention is used as a raw material, a SrTiO ₃ film, a (Ba, Sr)TiO ₃ film, or a SrRuO ₃ film containing ruthenium is formed. The film can reduce the content of K and Na in the film more than ever.

The method of supplying Sr(PrMe ₄ Cp) ₂ at the time of film formation can be carried out by heating Sr(PrMe ₄ Cp) ₂ to 130 to 350 ° C to form a liquid having fluidity, and by using a carrier gas a method of foaming and vaporizing it; or dissolving Sr(PrMe ₄ Cp) ₂ in an inert hydrocarbon solvent and supplying it by a liquid mass flow meter, and using a gasifier of 130 to 350 ° C to make it full Gasification method, etc.

When the Sr(PrMe ₄ Cp) ₂ is supplied by the foaming method, the cylinder temperature is not limited to the temperature of the following examples, and can be set between 130 and 350 ° C. The carrier gas at this time is only an inert gas, and N ₂ and He can be used in addition to A r . Further, when the flow rate is too small, the vapor cannot be transported. If the flow rate is too large, the internal pressure of the cylinder rises and the evaporation of the raw material is hindered. Therefore, it is preferably 30 to 500 sccm.

Further, when Sr(PrMe ₄ Cp) _{2 is} dissolved in a solvent to lower the viscosity and is vaporized by liquid transport in a vaporizer, the viscosity is not limited to the temperature of the following examples, and may be 50 cP or less. For this range of viscosity, the risk of blockage in the piping and gasifier can be reduced.

Further, the solvent is preferably a toluene having the highest solubility. However, when it is a solvent having a low concentration, it is not limited to toluene, and hexane or octane having excellent solubility can also be used.

If the vapor of Sr(PrMe ₄ Cp) ₂ vaporized by the aforementioned method is used, Ti(OiPr) ₄ , Ti(OtBu) ₄ , Ti(NMe ₂ ) ₄ , Ti(NEtMe) ₄ , Ti(NEt ₂ ) ₄ When a vapor of a titanium compound, oxygen, ozone, water or the like is used as an oxidizing agent, a SrTiO ₃ film can be produced by a CVD method or an ALD method.

Further, when in Sr (PrMe ₄ Cp) was added Ba (PrMe ₄ Cp) ₂ vapor ₂ vapor, and the use of _{Ti (OiPr) 4, Ti (} OtBu) 4, Ti (NMe 2) 4, Ti (NEtMe) 4, When a vapor of a titanium compound such as Ti(NEt ₂ ) ₄ and oxygen, ozone, water or the like is used as an oxidizing agent, a (Ba, Sr)TiO ₃ film can be produced by a CVD method or an ALD method.

Further, when Sr(PrMe ₄ Cp) ₂ vapor and a vapor of a ruthenium compound such as Ru(EtCp) ₂ and oxygen, ozone, water or the like are used as the oxidizing agent, the SrRuO ₃ film can be produced by a CVD method or an ALD method.

Example

Hereinafter, the present invention will be more specifically described based on examples, but the present invention is not limited to the following examples.

[First Embodiment] Production of Sr(PrMe ₄ Cp) ₂

In a 1 L three-necked flask equipped with a thermometer, a stirrer, an inlet, and a reflux, after dehydration of vacuum argon, 600 ml of dehydrated deoxidized THF and 75 g of Na(PrMe ₄ Cp) (0.40 mol) were injected and dissolved, and the flask was water-cooled. 72 g (0.21 mol) of SrI ₂ powder was added, and stirred at 40 ° C for eight hours.

Next, the solvent is removed under reduced pressure, and after drying, 600 ml of dehydrated deoxidized toluene is added, and extraction operation by heating and stirring is carried out, and after standing, filtration is carried out to obtain a transparent filtrate, and toluene is distilled off from the filtrate under reduced pressure, and The mixture was dried under reduced pressure at 100 ° C to obtain 89 g of pale yellow solid (dry-dried product) having a melting point of about 130 °C.

The solid was poured into a high-vacuum distillation apparatus and maintained at 110-160 ° C / 0.1-0.01 Torr for one hour. The THF of the THF adduct slowly separated and accumulated in the cryogenic separator 8.1 g. . After slowly raising the temperature and removing a trace amount of the preliminary distillation crystal, 61 g of a pale yellow viscous liquid which was subjected to main distillation was obtained at 170 to 180 ° C / 0.1 to 0.01 Torr.

The viscous liquid is again injected into the high vacuum distillation apparatus, and kept at 100-160 ° C / 0.1 ~ 0.01 Torr for about one hour, and a trace amount of residual THF is removed, and at 170 ~ 180 ° C / 0.01 ~ 0.1 Torr A pale yellow viscous liquid (secondary distillate) of main distillation was obtained in an amount of 56 g.

This secondary distillate was identified as Sr(PrMe ₄ Cp) ₂ (0.136 mol) in the results of the analysis described below, and its yield was 68% with respect to Na (P rMe ₄ Cp).

The methods and results of the identification analysis and physical property evaluation of the secondary distillation product are described below.

(1) Composition analysis As a result of ICP emission spectroscopic analysis of the liquid obtained by wet decomposition, the Sr content was 20.7% (theoretical value: 21.15%).

Further, in terms of impurities, Ca = 1900, Mg < 50, Ba = 10000, Na < 50, K < 50, Cr < 50, Fe < 50, Cu < 50, and Ni < 50 (unit: ppb), which is confirmed to be high purity. .

(2) ¹ H-NMR ( ¹ H-nuclear magnetic resonance) measurement conditions (device: JNM-ECA400 (400 MHz), solvent: C ₆ D ₆ , method: 1D)

The first graph shows the results of the measurement of the secondary distillate. For comparison, the second graph shows the results of the reduced-pressure dried product.

Considering the ratio of the position of each signal in the measurement spectrum of the first graph and the second graph to the number of H, the ratio of the number of H of Sr(PrMe ₄ Cp) ₂ and THF, the δH (ppm) is assigned as follows.

2.01 (s), 1.97 (s ) 12H: leaving the C ₅ (C H _{3) 4} of the -C ₃ H ₇ CH ₃ CH ₃ near to two two 2.39 (t) 2H: C H 2 CH 2 CH ₃ 1.36(m)2H:CH ₂ C H ₂ CH ₃ 0.92(t)3H:CH ₂ CH ₂ C H ₃ 3.14(t), 1.21(m): THF-OC H ₂ C H ₂ C H ₂ C H ₂ -

According to the measured spectrum shown in the first figure, the number of moles of the THF added to the Sr1 molar of the secondary distillation product is (0.348+0.437)/(23.562+4.131+4.136+6)×38/8=0.09, The average chemical formula constitutes Sr(PrMe ₄ Cp) ₂ (THF) _0.09 , and although THF is slightly coordinated, it can be regarded as substantially Sr(PrMe ₄ Cp) ₂ .

In addition, according to the measured spectrum shown in the second figure, the THF molar amount of the reduced-pressure dried strain added to Sr1 molar is (2.076+2.046)/(11.296+1.981+1.890+3)×38/8=1.08 The average chemical formula constitutes Sr(PrMe ₄ Cp) ₂ (THF) _1.08 .

Further, the theoretical value of the Sr content of Sr(PrMe ₄ Cp) ₂ (THF) ₁ was 18.02%, and the analysis value of the Sr content of the reduced-pressure dried product was 18.1%.

Accordingly, it is estimated that the reduced-pressure dried product is added with about one THF of Sr(PrMe ₄ Cp) ₂ .

(3) traits and melting point The secondary distillation product is slightly yellowish and is a highly viscous liquid at room temperature with a viscosity of about 1000P.

(4) Thermogravimetry/thermal differential analysis (TG-DTA) Measurement conditions (sample weight: 14.40 mg, gas atmosphere: Ar at a gas pressure, temperature increase rate: 10.0 deg/min)

The third graph shows the results of the measurement of the secondary distillate. For comparison, the fourth graph shows the results of the reduced-pressure dried product.

According to the TG-DTA curve shown in the third and fourth figures, twice There was no reduction in the distillate to around 160 ° C, and it was presumed that the removed THF did not exist.

In addition, since it evaporates by 97% at 300 ° C, it is not thermally deteriorated at 300 ° C or less in a short time, and the thermal stability required for the raw material having the ALD method or the CVD method can be confirmed.

(5) Vapor pressure The result of the gas saturation method was 0.1 Torr / 170 °C.

(6) The density density is 1.2 g/cm ³ (30 ° C).

(7) Solubility The solubility at room temperature with respect to 1 L of each solvent was 350 g with respect to toluene, 280 g with respect to THF, 70 g with respect to hexane, and 70 g with respect to octane.

Accordingly, it was confirmed that it was sufficiently dissolved in toluene, and it was also sufficiently dissolved in octane or the like.

[First Comparative Example] Production of Solvent Using SME (Sr(PrMe ₄ Cp) ₂ of DME

In a 300 ml three-necked flask equipped with a thermometer, a stirrer, an inlet, and a reflux, after dehydration with vacuum argon, 160 ml of dehydrated deoxidized THF and 16 g of Na(PrMe ₄ Cp) (0.086 mol) were injected and dissolved, and the flask was water-cooled. 15.5 g (0.045 mol) of SrI ₂ powder was added and stirred under reflux for eight hours.

Next, the solvent was removed under reduced pressure, and after drying, 200 ml of dehydrated deoxidized toluene was added, and extraction operation by heating and stirring was carried out, and after standing, filtration was carried out to obtain a transparent filtrate, and toluene was distilled off from the filtrate. When it was distilled off and dried under reduced pressure at 100 ° C, it was initially a pale yellow mucus, but 18.5 g of a solid having a melting point of about 100 ° C was obtained after one day.

The solid is injected into a high vacuum distillation apparatus and maintained at 110-160 ° C / 0.1 ~ 0.01 Torr for one hour, at which time the DME of the DME adduct will slowly detach and accumulate in the cryogenic separator 1.2 g . After slowly raising the temperature and removing a very small amount of preliminary distillation, the main distillation system obtains a pale yellow solid which is liquid distilled and solidified at room temperature (melting point about 50-80) at 170-175 ° C / 0.1-0.01 Torr. °C) (primary distillation) 14.7g.

The solid is again injected into the high vacuum distillation apparatus, and is heated at 100 to 160 ° C / 0.1 to 0.01 Torr for one hour, and then heated at 170 to 175 ° C / 0.01 to 0.1 Torr. The pale yellow solid (melting point about 50 to 80 ° C) (secondary distillation) which was distilled off and solidified at room temperature was 12.8 g.

This secondary distillation product was subjected to measurement of ¹ H-NMR and TG-DTA in the same manner as in the first example.

(1) ¹ H-NMR The fifth graph shows the measurement results of the secondary distillate.

Consider the ratio of the position of each signal in the measurement spectrum of the fifth graph to the number of H, the number of H of Sr(PrMe ₄ Cp) ₂ and DME, and the δH (ppm) is assigned as follows.

2.15 (s), 2.12 (s ) 12H: leaving the C ₅ (C H _{3) 4} of the -C ₃ H ₇ CH ₃ CH ₃ near to two two 2.47 (t) 2H: C H 2 CH 2 CH ₃ 1.63(m)2H:CH ₂ C H ₂ CH ₃ 1.08(t)3H:CH ₂ CH ₂ C H ₃ 2.69(t), 2.59(m): C H ₃ OC H ₂ C H ₂ OC H of DME ₃

According to the measured spectrum shown in the fifth figure, the molar number of the DME of the secondary distillation product added to the Sr1 molar is (2.921 + 1.961) / (11.726 + 1.945 + 1.901 + 3) × 38/10 = 1.00, The average chemical formula constitutes Sr(PrMe ₄ Cp) ₂ (DME) _1.00 .

Further, a signal due to a large amount of impurities can be seen, and it is presumed that thermal decomposition or the like of the adduct is generated in the heating distillation.

Further, the theoretical value of the Sr content of Sr(PrMe ₄ Cp) ₂ (DME) ₁ was 17.37%, and the analysis value of the Sr content of the secondary distillate was 18.2%.

Accordingly, in the vacuum heating distillation operation, it was confirmed that DME was difficult to separate from the DME adduct.

(2) TG-DTA The sixth graph shows the measurement results of the secondary distillate.

According to the TG-DTA curve shown in the sixth figure, the behavior of DME detachment was not found, and it was presumed that most of the evaporation was directly in the state of the DME adduct.

From the measurement results of the above ¹ H-NMR and TG-DTA, it was confirmed that even if the secondary distillation product was heated, DME did not desorb, and most of the DME was formed into a DME adduct and vaporized.

That is, if DME is used as a solvent and a method of adding a DME is used, pure Sr(PrMe ₄ Cp) ₂ cannot be obtained.

Accordingly, it is difficult to produce pure Sr(PrMe ₄ Cp) ₂ from commercially available Sr(PrMe ₄ Cp) ₂ (DME).

[Second Comparative Example] Production of Raw Material Using NaCp ^* of SrCp ^* ₂

In a 1 L three-necked flask equipped with a thermometer, a stirrer, an inlet, and a gas outlet, 750 ml of dehydrated deoxidized THF and NaCp ^* 79 g (0.50 mol) were injected and dissolved in a vacuum argon, and the flask was water-cooled and added with SrI ₂ powder. 90 g (0.246 mol) and stirred at 25-40 ° C for twenty-four hours.

Next, the solvent is removed under reduced pressure, and after drying, 900 ml of dehydrated deoxidized toluene is added, and extraction operation by heating and stirring is carried out, and after standing, filtration is carried out to obtain a transparent filtrate, and toluene is distilled off from the filtrate under reduced pressure, and The mixture was dried under reduced pressure at 100 ° C. When the solid component was taken out in a handle box and gently pulverized, 98 g of a pale yellow loose powder was obtained.

The powder was injected into a sublimator, and the first sublimation was carried out at 140-180 ° C / 0.1 Torr, and a sublimation product of 65 g was obtained.

Next, the sublimation product was injected into the sublimator, and the second sublimation was carried out at 140-180 ° C / 0.1 Torr, and 62 g of pure white sublimation product was obtained.

The crystal of the secondary sublimate product was identified as SrCp ^* ₂ (0.162 mol) in the results of the analysis described below, and the yield thereof was 69% with respect to NaCp ^* .

The composition analysis by ICP emission spectrometry and the measurement of ¹ H-NMR were carried out in the same manner as in the first example, for the solids obtained in each procedure.

As a result, the average chemical formula can be estimated as follows based on the ratio of the Sr content analysis value (theoretical value: 24.47%) to the H number of the total SrCp ^* ₂ signal of ¹ H-NMR and the H number of the THF signal.

Dry decompression product: Sr content 19.7% SrCp ^* ₂ (THF) _1.5

Sublimation product: Sr content 22.1% SrCp ^* ₂ (THF) _0.5

Secondary sublimation: Sr content 25.3% SrCp ^* ₂

Moreover, according to the results of ICP emission spectroscopic analysis, the impurity of the second sublimation product is Ca=2800, Mg<50, Ba=29000, Na=940, K<50, Cr<50, Fe<50, Cu<50, Ni< 50 (unit: ppb), the Na content greatly increased as compared with the first embodiment.

[Third Comparative Example] Production of Raw Material Using KCp ^* of SrCp ^* ₂

The synthesis was carried out using the same molar amount of the starting material by the same method as the second comparative example except that KCp ^* was used instead of NaCp ^* .

The yield of SrCp ^* ₂ was 65% relative to KCp ^* .

As in the first embodiment, the composition and impurity analysis by ICP emission spectroscopic analysis were performed on the secondary sublimation product.

As a result, the Sr content analysis value was 25.0% (theoretical value 24.47%), the impurity system Ca=3000, Mg<50, Ba=3. 1000, Na<50, K=1100, Cr<50, Fe<50, Cu<50, Ni<50 (unit: ppb), the K content greatly increased compared to the first embodiment.

[Fourth Comparative Example] Manufacture of Sr(dpm) ₂

In a 500 ml four-necked flask equipped with a thermometer, a stirring impeller, and a refluxing device, 350 ml of toluene was injected after vacuum argon substitution, and secondly, 65.6 g (356 m millimolar) of dipentahyl methane (dpmH) and 7.8 g of metal were injected. 89 m millimolar) was stirred with heating and allowed to react under reflux for twenty-four hours at which time the metal piece disappeared.

Next, the solvent and the unreacted dpmH were distilled off under reduced pressure, and the dissolved trace amount of dpmH was distilled off at 130 ° C and 0.05 Torr.

34 g of the residue was poured into a high vacuum distillation apparatus, and distillation was carried out at 230 ° C / 0.02 Torr, and Sr(dpm) ₂ 30 g was obtained.

As in the first embodiment, as a result of performing impurity analysis by ICP emission spectrometry, Na = 920, K = 890 (unit: ppb), the contents of Na and K were greatly increased as compared with the first embodiment. .

[Second embodiment] Formation of SrTiO ₃ film using Sr(PrMe ₄ Cp) ₂ and using ALD method (1)

The cylinder (A) filled with Sr(PrMe ₄ Cp) ₂ obtained by the first embodiment was foamed at 170 ° C with an argon (Ar) gas of 100 sccm, and argon (Ar) gas was 100 sccm at 40 ° C. The cylinder (B) filled with Ti(OiPr) ₄ was foamed, and the cylinder (C) filled with water was bubbled with argon (Ar) gas at 50 sccm at 20 ° C, and the flushing system was allowed to flow Ar 200 sccm, and each was Pulse for one second and rinse for three seconds for ALD operation.

Place the Si substrate with a substrate temperature of 300 ° C in an ALD chamber with a pressure of about 5 Torr, and use the Sr cycle of (A pulsation-flush-C pulsation-flush) and the Ti cycle using (B pulsation-flush-C pulsation-flush) Each 100 cycles were performed alternately, and a SrTiO ₃ film having a thickness of 10 nm was obtained.

[Third embodiment] Formation of Sr(RrMe ₄ Cp) ₂ using SrTiO ₃ film by ALD method (2)

The film formation is performed by a film chamber having a chamber wall including a gas introduction port, a resistance heating heater heater for wafer heating, and a lifting mechanism for wafer installation, and the film forming chamber is transmitted through a pressure regulating valve and an exhaust gas. The pump was connected and maintained at 160 ° C by an intervening heater embedded in the chamber wall, and the carrier heater was set at 320 ° C to set the wafer temperature to 290 ° C at about 0.3 Torr.

Using a transfer arm, a 300 mm diameter Si wafer was introduced from the transport system into the film forming chamber and transferred to the load heater, and then argon (Ar) gas was passed through 500 sccm, and the pressure in the chamber was maintained at 1 Torr by a pressure regulating valve. And the temperature of the wafer is raised.

The Sr(PrMe ₄ Cp) ₂ 100 g obtained in the first embodiment was filled in the foaming cylinder (A) and maintained at 165 ° C, and the carrier gas system circulated and foamed argon (Ar) gas at 50 sccm while Sr(PrMe ₄ Cp) ₂ vapor was obtained. Further, the cylinder (B) filled with Ti(OiPr) ₄ was kept at 45 ° C, and argon (Ar) gas was passed through 200 sccm to foam, and Ti (Oi Pr) ₄ vapor was obtained. Further, a cylinder filled with water as an oxidizing agent was kept at 80 ° C, and a high-temperature mass flowmeter was placed on the outlet side to flow H ₂ O gas at 200 sccm (C), and further, Ar200 sccm was used for the flushing gas system.

The supply of these raw materials or oxidants (hereinafter referred to as pulsation) and rinsing are pulsating for five seconds and rinsing for ten seconds to perform the following ALD operation. Since the pressure control valve of the chamber is opened during pulsation or flushing, the indoor The pressure system constituted a pulsation A according to the gas flow rate in the room: 0.3 Torr, pulsation B: 0.4 Torr, pulsation C: 0.5 Torr, and rinsing: 0.2 Torr. The wafer system was maintained at about 290 °C during these ALD operations.

The SrO formation cycle using (A pulsation-flush-C pulsation-rinsing) and the TiO ₂ formation cycle by (B pulsation-rinsing-C pulsation-rinsing) were performed for 77 cycles in total, and the SrO/TiO ₂ cycle ratio was constituted = 1.3. Specifically, (A pulsation-flush-C pulsation-flush) 2 cycles, (B pulsation-flush-C pulsation-flush) 2 cycles, (A pulsation-flush-C pulsation-flush) 2 cycles, (B The pulsation-flush-C pulsation-flushing one of the 1 cycles was set once, and it was repeated ten times to form a SrTiO ₃ film having a thickness of 5 nm.

When the formed film composition was investigated by XRF (fluorescence X-ray analysis), Sr/Ti = 1.4.

In addition, when the film was formed at the beginning of Sr(PrMe ₄ Cp) ₂ and 25 sheets were used, the average film thickness was 53.5. With 50.3 The standard deviation of the in-plane thickness distribution is 1.6% and 1.3%, and the standard deviation of the film thickness distribution between the two sheets is 2.8% and 3.3%. It is used at the beginning of Sr(PrMe ₄ Cp) ₂ and ends roughly. There was almost no difference in film formation characteristics at the time of use of 90 g.

[Fifth Comparative Example] Formation of SrTiO ₃ film using SrCp ^* ₂ and using ALD method (1)

Film formation was carried out in the same manner as in the third example except that SrCp ^* ₂ was used instead of Sr(PrMe ₄ Cp) ₂ .

When the film was formed at the beginning of SrCp ^* ₂ 100g and 25 sheets were used, the average film thickness was 55.2. With 43.2 The Sr/Ti ratio of the film material was also 0.8 with respect to the initial use of 1.4 and 90 g, and the supply amount of SrCp ^* ₂ was remarkably lowered.

According to the third embodiment and the fifth comparative example, since Sr(PrMe ₄ Cp) ₂ is a liquid at the foaming temperature, the vapor can be stably supplied from the start to the end of the filling amount of 100 g.

On the other hand, since SrCp ^* ₂ is solid at the temperature at which foaming is carried out, the use of the filling amount of 100 g is completed until the end of the filling, and the evaporation surface area due to the condensation of the powder is reduced, and the raw material is cooled to the cylinder or the piping. The heat transfer due to condensation is insufficient, and the supply amount of the film-forming raw material tends to decrease, whereby the film thickness under the same film formation conditions is reduced or the Sr/Ti ratio is lowered.

[Fourth Embodiment] Formation of SrTiO ₃ film using Sr(PrMe ₄ Cp) ₂ and using ALD method (3)

The film forming chamber was set to the same conditions as in the third embodiment.

The Sr(PrMe ₄ Cp) ₂ obtained in the first embodiment was filled in the foaming cylinder (A) and maintained at 155 ° C, and the carrier gas system circulated and foamed argon (Ar) gas at 50 sccm while obtaining Sr(PrMe ₄ Cp) ₂ vapor. Further, the cylinder (B) filled with Ti(OiPr) ₄ was held at 55 ° C, and argon (Ar) gas was passed through 200 sccm to foam, and Ti (OiPr) ₄ vapor was obtained. Further, the oxidizing agent was passed through a mixed gas of O ₂ /N ₂ =500/0.5 sccm to an ozone generator to obtain an O ₃ gas (C) having a concentration of 180 g/m ³ , and further, Ar200 sccm was used for the flushing gas system.

The pulsation and rinsing were performed by pulsing A and B for ten seconds, C pulsing for two seconds, and rinsing for ten seconds to perform the following ALD operation.

The SrO formation cycle using (A pulse-flush-C pulsation-flush) and the TiO ₂ formation cycle by (B-pulse-flush-C pulsation-flush) were performed for 77 cycles in total, and the SrO/TiO ₂ cycle ratio was set to 1.2. Specifically, (A pulsation-flush-C pulsation-flush) 2 cycles, (B pulsation-flush-C pulsation-flush) 2 cycles, (A pulsation-flush-C pulsation-flush) 2 cycles, (B Pulsation-flush-C pulsation-flush) 2 cycles, (A pulsation-flush-C pulsation-flush) 2 cycles, (B pulsation-flush-C pulsation-flush) One cycle of one cycle is set once and repeated A 5 nm thick SrTiO ₃ film was formed seven times.

When the composition of the formed film was investigated by the XRF method, Sr/Ti = 1.25.

[Fifth Embodiment] Formation of Sr(RrMe ₃ Cp) ₂ and SrTiO ₃ film by ALD method (4)

The film forming chamber was set to the same conditions as in the third embodiment.

Sr(PrMe ₄ Cp) ₂ obtained by the first example was dissolved in toluene, and a 0.4 mol/l solution having a viscosity of 40 cP was prepared.

The solution was guided to a gasifier which had been heated to 200 ° C using a liquid supply system, and 200 sccm of argon (Ar) gas was used as a carrier gas, and the gas flow meter was controlled at one side with a flow rate of 0.3 g/min. Simultaneously, Sr(PrMe ₄ Cp) ₂ gas (A) was obtained. Further, a liquid supply system was used to guide Ti(OiPr) ₄ to a gasifier which had been heated to 100 ° C, and argon (Ar) gas was 200 sccm as a carrier gas, and a flow rate of 0.1 g/min was used by a liquid flow meter. The control side is vaporized while obtaining Ti(OiPr) ₄ vapor. Further, the oxidizing agent was passed through a mixed gas of O ₂ /N ₂ =500/0.5 sccm to an ozone generator to obtain an O ₃ gas (C) having a concentration of 180 g/m ³ , and further, Ar200 sccm was used for the flushing gas system.

The pulsation and rinsing were performed by pulsing A and B for two seconds, C pulsing for two seconds, and rinsing for five seconds to perform the following ALD operation.

The SrO formation cycle using (A pulsation-flush-C pulsation-rinsing) and the TiO ₂ formation cycle by (B pulsation-rinsing-C pulverization-rinsing) were performed for 99 cycles in total, and the SrO/TiO ₂ cycle ratio was set to 1.2. Specifically, (A pulsation-flush-C pulsation-flush) 2 cycles, (B pulsation-flush-C pulsation-flush) 2 cycles, (A pulsation-flush-C pulsation-flush) 2 cycles, (B Pulsation-flush-C pulsation-flush) 2 cycles, (A pulsation-flush-C pulsation-flush) 2 cycles, (B pulsation-flush-C pulsation-flush) One cycle of one cycle is set once and repeated A SrTiO ₃ film having a thickness of 6.4 nm was formed nine times.

Use the SrTiO ₃ film and put it on. When the lower electrode is simultaneously made of Ru to form a MIM (Metal Insulator Metal) structure, and the SrTiO _{3 is} crystallized by heat treatment at 600 ° C, the film thickness of the oxide film is 0.7 nm, and the voltage is 1 V when the voltage is applied. The current is 3.5 x 10 ^-7 A/cm ² .

[Sixth Comparative Example] Formation of SrTiO ₃ film using SrCp ^* ₂ and using ALD method (2)

Film formation was carried out in the same manner as in the fifth example except that a SrCp ^* ₂ 0.2 mol/l toluene solution was used instead of the Sr(PrMe ₄ Cp) ₂ 0.4 mol/l toluene solution.

The SrO formation cycle using (A pulsation-flush-C pulsation-rinsing) and the TiO ₂ formation cycle by (B pulsation-rinsing-C pulverization-rinsing) were performed for 99 cycles in total, and the SrO/TiO ₂ cycle ratio was set to 1.2. Specifically, (A pulsation-flush-C pulsation-flush) 2 cycles, (B pulsation-flush-C pulsation-flush) 2 cycles, (A pulsation-flush-C pulsation-flush) 2 cycles, (B Pulsation-flush-C pulsation-flush) 2 cycles, (A pulsation-flush-C pulsation-flush) 2 cycles, (B pulsation-flush-C pulsation-flush) One cycle of one cycle is set once and repeated A SrTiO ₃ film having a thickness of 8.2 nm was formed nine times.

When the SrTiO ₃ film was used and the upper and lower electrodes were simultaneously formed into Ru to form an MIM structure, and the SrTiO _{3 was} crystallized by heat treatment at 600 ° C, the film thickness of the oxide film was 0.9 nm, and the leakage current at a voltage of 1 V was applied. It is 2.4 × 10 ^-3 A/cm ² .

Compared with the SrTiO ₃ film of the fifth embodiment, the SrTiO ₃ film has a large physical thickness and an oxide film thickness, but the leakage current is large.

The SrTiO ₃ films of the fifth embodiment and the sixth comparative example were each formed on a Si substrate at a film thickness of 5 nm, and when the Na content was compared by TXRF (total reflection fluorescent X-ray) analysis, the sixth comparative example was Two times the five embodiments.

From this, it is understood that compared with Sr(PrMe ₄ Cp) ₂ , since there are many impurities such as Na of SrCp ^* 2, electrical characteristics are deteriorated.

[Sixth embodiment] Formation of SrRuO ₃ film using Sr(PrMe ₄ Cp) ₂ and using ALD method

In the film forming chamber, the setting of the load heater was set to 350 ° C to set the wafer temperature to 330 ° C at 0.3 Torr, and otherwise the same conditions as those in the third embodiment were set.

Sr(PrMe ₄ Cp) ₂ obtained by the first example was dissolved in toluene to prepare a 0.4 mol/l solution. The solution was guided to a gasifier which had been heated to 200 ° C using a liquid supply system, and 200 sccm of argon (Ar) gas was used as a carrier gas, and the gas flow meter was controlled at one side with a flow rate of 0.3 g/min. Simultaneously, Sr(PrMe ₄ Cp) ₂ gas (A) was obtained. Further, Ru(EtCp) _{2 was} guided to a gasifier which had been heated to 120 ° C using a liquid supply system, and 200 sccm of argon (Ar) gas was used as a carrier gas, and a flow rate of 0.1 g/min was used by a liquid flow meter. The control side is vaporized while obtaining Ru(EtCp) ₂ vapor. Further, the oxidizing agent was passed through a mixed gas of O ₂ /N ₂ =500/0.5 sccm to an ozone generator to obtain an O ₃ gas (C) having a concentration of 100 g/m ³ , and further, Ar200 sccm was used for the flushing gas system.

The pulsation and flushing are pulsed by A and B for one second, and C is pulsed for one second. Rinse for two seconds for the ALD operation described below.

The SrO formation cycle using (A pulsation-flush-C pulsation-flush) and the RuO ₂ formation cycle by (B pulsation-flush-C pulsation-rinsing) were performed for 240 cycles in total, and the SrO/RuO ₂ cycle ratio was constituted. Specifically, one cycle of (A pulsation-flush-C pulsation-flush) 2 cycles, (B pulsation-flush-C pulsation-flush) 2 cycles is set once, and it is repeated for 60 times to form a thickness. 18 nm SrRuO ₃ film.

[Seventh embodiment] Production of Sr(RrMe ₃ Cp) ₂ using SrTiO ₃ film by CVD method

The cylinder filled with Sr(PrMe ₄ Cp) ₂ obtained by the first embodiment was bubbled with argon gas at 50 sccm at 160 ° C and an internal pressure of about 5 Torr, and Sr (PrMe ₄ Cp) ₂ vapor was sent to the CVD. room.

At the same time, a cylinder filled with Ti(NMe ₂ ) ₄ was bubbled with argon gas at 50 sccm at 30 ° C and an internal pressure of about 5 Torr, and Ti(NMe ₂ ) ₄ vapor was sent to the CVD chamber.

Further, 100 sccm of oxygen was sent to the CVD chamber.

When these gases were mixed at the inlet of the CVD chamber and introduced into a Si (100) substrate maintained at 2 Torr and 350 ° C, a SrTiO ₃ film having a thickness of 60 nm was formed in thirty minutes.

[Eighth Embodiment] Production of SrRuO ₃ film using Sr(PrMe ₄ Cp) ₂ and using CVD method

The cylinder filled with Sr(PrMe ₄ C p) ₂ obtained by the first embodiment was bubbled with argon gas at 50 sccm at 160 ° C and an internal pressure of about 7 Torr, and Sr (PrMe ₄ Cp) ₂ vapor was sent. CVD chamber.

At the same time, a cylinder filled with Ru(EtCp) ₂ was bubbled with argon gas at 50 sccm at 30 ° C and an internal pressure of about 7 Torr, and Ru(EtCp) ₂ vapor was sent to the CVD chamber.

When these gases were mixed at the inlet of the CVD chamber and introduced into a SrTiO ₃ (100) substrate maintained at 5 Torr and 700 ° C, a SrRuO ₃ film having a thickness of 80 nm was formed in thirty minutes.

However, the above description is only a detailed description of the preferred embodiments of the present invention, and the present invention is not limited thereto, and is not intended to limit the present invention. The scope of the patent application is subject to the scope of the present invention, and any one skilled in the art can easily include it in the field of the present invention. Any changes or modifications considered may be covered by the patents in this case below.

FIG lines showed about a first measurement of ^a secondary distillation product H-NMR spectrum of a first embodiment of the embodiment; FIG second measurement system of the first embodiment about the reduced pressure of the dried product ¹ H-NMR spectrum of the display; The third graph shows the results of the TG-DTA measurement of the second distillation product of the first embodiment at 1 atm; the fourth graph shows the TG-DTA of the vacuum-dried product of the first embodiment at 1 atm. The measurement result chart; the fifth chart shows the measured spectrum of ¹ H-NM R of the second distillation product of the first comparative example; and the sixth figure shows the secondary distillation product of the first comparative example at 1 atm. TG-DTA measurement results.

Claims (2)

A raw material for forming a film containing bismuth, characterized by being bis(propenylcyclopentadienyl) fluorene having a content of Na and K of 50 ppb or less. A method for producing a raw material for forming a film containing ruthenium, which is obtained by the following procedure, that is, sodium propylenetetramethylcyclopentadiene or propylenetetramethylcyclopentane a procedure in which a potassium enelate is reacted with cerium iodide in tetrahydrofuran to form a tetrahydrofuran addition product of bis(propenylcyclopentadienyl) hydrazine; a tetrahydrofuran is distilled off, and a toluene solution is prepared by extraction with toluene; The procedure of toluene and drying under reduced pressure; and heating under vacuum to 100-160 ° C, and distillation after dissociation to remove tetrahydrofuran.