KR20210095521A - The novel preparation of the organic compound constituting a precursor for in the ALD / CVD process - Google Patents

Abstract

The present invention relates to a method for preparing a compound represented by chemical formula 1 and a compound represented by chemical formula 2 as an organic ligand compound forming a precursor used for self-limiting reaction, among the precursors used in a process selected from the group consisting of atomic layer deposition (ALD) and chemical vapor deposition, with high purity and high efficiency in an eco-friendly manner using no organic solvent. The present invention is advantageous in that the compound represented by chemical formula 1 and the compound represented by chemical formula 2 are prepared in an aqueous solution, not an organic solvent used conventionally in the related art, and the byproducts generated during the preparation are removed with ease.

Description

The novel preparation of the organic compound constituting a precursor for in the ALD / CVD process

The present invention provides a self-limiting reaction among precursors used in a process selected from the group consisting of atomic layer deposition (ALD) and chemical vapor deposition (Chemical Vapor Deposition). Ligand constituting a precursor Organic compound Formula 1 compound and Formula 2 compound

[Formula 1]

[Formula 2]

It relates to a manufacturing method that can be prepared in an aqueous solution with high purity and high efficiency without using an organic solvent in a nature-friendly method.

A precursor used in a semiconductor process is commonly referred to as a precursor used to form a specific thin film (metal, metal oxide film, or metal nitride film). That is, the precursor is generally an organometallic compound in which a central metal and a ligand are bonded, and the compounds of Chemical Formulas 3 and 4 are responsible for one component of the ligand. Various ligands that can be used as precursors have been studied, and representative examples include alkoxide, diene, β-diketonato, diazadiene, aryl, There are alkylamido groups, cyclopentadiene, and the like, and the compound to be developed by the present inventors is also a derivative of cyclopentadiene.

It has been previously reported in many literatures that the properties of the precursor may vary depending on the composition of the various ligands, and that the properties of the precursor may have a significant effect on the final film.

Summarizing the characteristics of general precursors,

First, thermal stability.

As a method of transferring the precursor to the deposition chamber, there are a method of transferring the volatilized precursor after heating and a method of volatilizing the precursor after transferring it to the chamber. An increase should not occur.

Second, it must have good volatility.

Since the volatility of the precursor affects the uniformity and step coverage of the entire wafer during the step-up process, the volatility of the precursor plays an important role in order to quickly penetrate and deposit uniformly.

Third, the reactivity of the surface and reaction gas should be good.

This is because, since the ALD process is a surface self-limiting deposition method, if the reactivity is low, self-limiting deposition is not performed.

Fourth, most important is the purity of the precursor.

Since semiconductor devices are very fine, even a small amount of impurities may cause device defects. In addition, in the case of a thin film requiring electrical properties, an ultra-high purity precursor must be used because the electrical properties change depending on the amount of trace metal and components other than the desired film component.

As described above, the development of a precursor having thermal stability, high volatility, high reactivity of surface, and high purity is urgently required.

Recently, as a material used for DRAM capacitors, zirconia (ZrO ₂ ) is mainly used as _{a material having a dielectric constant higher than that of SiO 2 .} Zirconia (ZrO ₂ ) It requires a special precursor to grow by the ALD method, so far, numerous precursors have been developed.

Among them, the alkoxide-based Zr precursor has a problem in the ALD process due to the limitation of thermal stability (J. Niinisto et al., Adv. Eng. Mater. 2009, 11, 223),

Since the β-Diketonato series precursor is a stable compound, a strong oxidizing agent such as Ozone is required, but it is not suitable for application to DRAM capacitors due to its low deposition rate (M. Putkone et al. ., J. Mater. Chem. 2002, 12, 442~4480)

Another candidate group, tetrakis-ethyl-methyl-amino-zirconium (TEMAZr), a precursor of the alkylamido group, has good volatility and good reactivity with Ozone for industrial application. (D. Hausmann et al., 2002, 14, 4350) However, thermal decomposition occurred at 300℃ due to low thermal stability, so a new type of precursor was required.

As an alternative compound, the cyclopentadiene (Cp) ligand, which is often used in metallocene catalyst compounds, was introduced, and the thermal stability of the precursor was dramatically increased. Among Cp-type precursors, RCpZr[N(CH ₃ ) ₂ ] ₃ (R = H, Methyl, Ethyl), [CH ₃ Cp) ₂ Zr(CH ₃ ) ₂ , (CH ₃ Cp) ₂ ZrCH ₃ OCH ₃ , Cp ₂ Zr(CH ₃ ) ₂ , and RCpZr(CHIT)(CHIT = Cycloheptatrienyl) have been _{developed as ALD precursors that form ZrO 2} with a thickness of several tens of nm (L. Aarik et al. Thi Solid Film). 2014, 565, 37~44; J. Niinisto et al. Langmuir 2005, 21, 7321~7325; J. Niinisto et al. Chem. Meter. 2012, 24, 2002~2008) Cp- applied in the current semiconductor process As a type, cyclopentadienyl trisdiamido zirconia [RCpZr[N(CH ₃ ) ₂ ] ₃ ( R = H): CpTDMAZ] compound is used as a precursor in the ALD process. This compound is a liquid at room temperature and has a high vapor pressure. It is stable at a high deposition temperature compared to tetrakis-ethyl-methyl-amino-zirconium (TEMAZr), so it is used in the ALD process. is considered to be possible. However, this compound is known to be a side reaction product in the ALD process.

Most recently, organic zirconium compounds, Chemical Formulas 3 and 4, which have higher thermal stability and volatility than TEMAZ and CpTDMAZ, and do not decompose even when stored for a long time at high temperatures, were developed as precursors and applied to the atomic layer deposition (ALD) process. became

Schematic of the synthesis reaction for preparing the compounds of Chemical Formula 3 and Chemical Formula 4, which are the above organic zirconium compounds, can be represented by Reaction Scheme 1 and Reaction Scheme 2.

[Reaction Diagram 1]

[Reaction diagram 2]

As mentioned above, the precursor can be applied stably in the ALD process only when a high-purity product is necessarily used. The purity of the cyclopentadienyl derivative, which is an organic ligand used in Schemes 1 and 2, determines the purity of the precursor. Therefore, to obtain cyclopentadienylethylmethylamine (hereinafter CpEMA) of the following formula (3), which is a cyclopentadienyl derivative, which is an organic ligand, and cyclopentadienylpropylmethylamine (hereinafter, CpPMA) of the following formula (4) with high purity It is a fact that the manufacturing process for this purpose must be accompanied, and a lot of research has been conducted for this purpose.

[Formula 1]

[Formula 2]

The compound CpEMA of Formula 1 may be prepared as shown in Scheme 3.

[Reaction diagram 3]

Compound 1 of the drawings is a reaction metal element (metal source) with sodium hydride in mineral emulsion (NaH in mineral oil) or sodium tert-butoxide (Sodium tert -butoxide), or Potassium tert-butoxide (Potassium tert -butoxide) in tetrahydrofuran (THF) is a common manufacturing process for producing it by using a solvent.

In addition, the halogen salt of compound 2 is easily prepared according to the literature (Organic Syntheses: Wiley: New York, 1943; Collective volume 4, p 333).

The compound CpPMA of Formula 2 may be prepared as shown in Scheme 4.

[Reaction diagram 4]

The halogen salt of compound 3 is easily prepared according to the general synthesis reaction shown in the following scheme.

As mentioned above, in general, the purity of the cyclopentadienyl derivative constituting the ligand of the precursors of Formulas 1 and 2 is important, and various studies have been conducted to easily remove impurities depending on the method of preparing the derivative. It is being attempted.

[Prior art literature]

J. Niinisto et al., Adv. Eng. Mater. 2009, 11, 223

M. Putkone et al., J. Mater. Chem. 2002, 12, 442~4480

D. Hausmann et al., 2002, 14, 4350

Organic Syntheses: Wiley: New York, 1943; Collective volume 4, p 333

Accordingly, an object of the present invention is to provide a preparation method capable of preparing the ligands of the precursors of Chemical Formulas 1 and 2 with high purity and high efficiency in an aqueous solution in a nature-friendly method without using an organic solvent.

The compound according to the present invention provides a process for preparing CpEMA of Formula 1 and CpPMA of Formula 2 with high purity.

[Formula 1]

[Formula 2]

The compound of Formula 3 is prepared by the following reaction as mentioned above.

[Reaction diagram 5]

There is a method for preparing sodium cyclopentadienyl sodium in a tetrahydrofuran (THF) solvent using sodium hydride mineral emulsion (NaH in mineral oil) as a metal source. However, since hydrogen gas is generated at the same time as sodium hydride mineral emulsion is added, there is a risk of explosion. Therefore, when mass-produced, the input rate must be maintained very slowly, which is not suitable for industrial, industrial and stable mass production.

In addition metal source (metal source) with sodium tert-butoxide (Sodium tert -butoxide) or potassium tert-butoxide (potassium tert -butoxide) the tetrahydrofuran (THF) was dissolved in a solvent by introducing a cyclo-penta-diene cyclo penta die It is known that enyl sodium or cyclopentadienyl potassium is prepared and then used in this reaction.

In general, it is common to separate and purify CpEMA products by distilling them at 25-32°C in a high vacuum (0.1-0.3 torr). However, the problem is that very trace amounts (0.01~0.05%) of tert-butanol, which is a by-product from the use of sodium tertbutoxide or potassium tertbutoxide during the purification process, remain, which is a serious problem in the synthesis of precursors. It is becoming. That is, a trace amount of the compound of 4 represented in Reaction Scheme 6 below is generated, and this compound is known to be an tolerance that interferes with Atomic Layer Deposition (ALD). Therefore, it is true that a lot of purification work is required to remove tert-butanol, and the economic loss due to a decrease in yield is very large.

[Reaction diagram 6]

And as indicated in Reaction Scheme 5, 1 equivalent of cyclopentadienyl sodium or cyclopentadienyl potassium is used in 2 equivalents for the main reaction, and the remaining 1 equivalent is used for neutralization of the amine salt. Then, cyclopentadiene is produced again. The generated cyclopentadiene is known to cause a polymerization reaction during the reaction to form dicyclopentadiene (Encyclopedia of Polymer Science and Technology vol 5, 759~776), and the compound in Reaction Scheme 7 5, polymerization takes place. That is, it is known that the polymerization rate proceeds at a rate of 2.5 to 3.5 mol%/Hr at 20 to 25° C. during the reaction. Polymerized dicyclopentadiene has similar physical properties (boiling point) when distilling the ligand CpEMA, so it is difficult to remove it. Therefore, it is convenient to use the ligand product if it is properly removed in the work-up operation after the completion of the reaction. It has the advantage of being separable.

[Reaction diagram 7]

In addition, when CpEMA exists as a single substance at room temperature, it is very unstable and has a very fast decomposition rate. When stored at -20°C, 5-10% decomposition after 24 hours was confirmed by gas chromatography analysis, even at -50°C. In the case of storage, degradation was observed even after long-term storage of more than 10 days. Therefore, the ligand CpEMA must be converted into the precursor compound of Formula 5 immediately after preparation.

[Formula 3]

Since it is difficult to store the ligand in general mass production and the decomposition rate is very fast at low temperature, the development of a structure with thermal stability that can increase industrial applicability is urgently needed.

In the manufacturing process of CpPMA of Formula 4, as mentioned in CpEMA of Formula 3, a very small amount (0.01~0.05%) of tert-butanol, which is a by-product, remains. This is a serious problem when synthesizing the precursor. , which is illustrated in Reaction Scheme 8 below.

[Reaction diagram 8]

In addition, CpPMA is also very unstable at room temperature, so the decomposition rate is very fast, and the ligand CpPMA is also converted into the precursor compound of Formula 4 immediately after preparation.

[Formula 4]

As described above, the present inventors have found that tertbutanol (tert butanol), which is a by-product from the use of sodium tertbutoxide or potassium tertbutoxide in the process of preparing the ligand organic compounds, the compounds of Formula 1 and the compounds of Formula 2, constituting the precursor as described above. -Butanol) is not generated, and the by-product dicyclopentadiene is removed in one process to provide a method to simplify the process.

Hereinafter, in order to explain the present invention in more detail, a preferred method according to the present invention is described in more detail with reference to the accompanying scheme. However, the present invention is not limited to the examples described herein and may be embodied in other forms.

The ligand, the compound of Formula 1, can be prepared by carrying out the method described in Scheme 1 below.

[Scheme 1]

Scheme 1 for preparing the ligand CpEMA, which is a cyclopentadienyl derivative of the present invention, is detailed step-by-step as follows.

[CpEMA manufacturing step 1]

Step 1 is a step for preparing Cp Potassium salt solution.

[Scheme 2]

A step of preparing a metal element (metal source) with potassium hydroxide (Potassium hydroxide) was dissolved in the distilled water charged into the cyclo-penta-diene cyclo penta the diene days potassium are dissolved in the aqueous solution used in the above reaction scheme.

The equivalent of potassium hydroxide used for dissolving cyclopentadiene is dissolved using 2.5 to 4.0 equivalents, and preferably 3.5 equivalents is used to dissolve at 10 to 15° C., and then the coupling step is performed.

[CpEMA manufacturing step 2]

In step 2, a solution of 2-bromo-N-methylethanamine hydrobromide in distilled water is added to the reaction solution in which cyclopentadienyl potassium is dissolved, and the by-product dicyclopentadiene (DCPD) is a step of preparing a mixed CpEMA potassium salt solution.

The process of step 2 is represented by Scheme 3 below.

[Scheme 3]

To the reaction solution prepared in Scheme 2 of Step 1, an aqueous solution of 2-bromo-N-methylethanamine bromate dissolved in an aqueous solution is slowly added at 0 to 10° C. to prepare a reaction solution in which the desired CpEMA potassium salt is dissolved. The equivalent ratio of 2-bromo-N-methylethanamine bromate used for coupling is 1.00 to 1.50 equivalents based on cyclopentadiene, preferably 1.25 equivalents, and the ratio of distilled water for dissolving is 2-bromide. The mother-N-methylethanamine bromate is dissolved using 1.75 to 2.0 times the weight ratio, and the temperature at which CpEMA potassium salt is added to the solution is added dropwise in the range of 0°C to +10°C, preferably 5 to 8°C. to prepare an aqueous CpEMA potassium salt solution. If dicyclopentadiene (DCPD), which is a by-product in this process, is analyzed by gas chromatography, 2-3% is observed.

[CpEMA manufacturing step 3]

In step 3, a pure CpEMA potassium salt solution is prepared by simply removing dicyclopentadiene (DCPD), a by-product, from the prepared CpEMA potassium salt aqueous solution using an organic solvent.

The process of step 3 is represented by Scheme 4 below.

[Scheme 4]

In the CpEMA potassium salt aqueous solution prepared in step 2, a volume of n-hexane was added 3 to 5 times the weight ratio, stirred for 30 minutes at 10 to 15° C., and left still, followed by layer separation to remove dicyclopentadiene. An aqueous solution of CpEMA potassium salt is obtained at 98.5 to 99.5% by analysis of high purity CpEMA using gas chromatography (Gas Chromatography: GC).

[CpEMA manufacturing step 4]

In step 3, the prepared CpEMA potassium salt aqueous solution is acidified using an inorganic acid, and then pure CpEMA is simply prepared using an organic solvent.

The process of step 4 is represented by Scheme 5 below.

[Scheme 5]

When the solution is acidified using the used dilute hydrochloric acid 3N hydrochloric acid, the pH range is 2 to 4, preferably adjusted to pH 2.5*, and 5 times of n-hexane to be added after acidification is suitable.

The obtained CpEMA solution is subjected to anhydrous dehydration reaction with anhydrous magnesium sulfate or anhydrous sodium sulfate, followed by filtration and distillation to obtain high-purity, clear CpEMA.

The ligand CpPMA of Formula 2, which is the cyclopentadienyl derivative of the present invention, can also be prepared by the same process steps as CpEMA, and in simple terms, it can be prepared by carrying out the method described in Scheme 6 as follows.

[Scheme 6]

Scheme 6 for preparing the ligand CpPMA, which is a cyclopentadienyl derivative of the present invention, is divided into steps as follows, and the reaction conditions and preparation method are the same as those of CpEMA.

[CpPMA manufacturing step 1]

In step 1, the Cp Potassium salt solution is prepared and proceeds in the same manner as CpEMA.

[CpPMA manufacturing step 2]

In step 2, a solution of 2-bromo-N-methylpropylamine hydrobromide in distilled water is added to the reaction solution in which cyclopentadienyl potassium is dissolved, and the by-product dicyclopentadiene (DCPD) is a step of preparing a mixed CpEMA potassium salt solution.

[CpPMA manufacturing step 3]

In step 3, a pure CpPMA potassium salt solution is prepared by simply removing dicyclopentadiene (DCPD), a by-product, from the prepared CpPMA potassium salt aqueous solution using an organic solvent.

The process of step 6 is represented by Scheme 8 below.

As described above, under each of the conditions of the preparation steps presented above, the reaction step of the ligand CpEMA and CpPMA, which are cyclopentadienyl derivatives, is performed in an aqueous solution, thereby providing CpEMA and CpPMA of high purity.

According to the present invention, a method for preparing and isolating a cyclopentadienyl derivative compound of high purity much more easily than the post-production purification method described in the existing patent method was found, which became the basis for completing the present invention.

Therefore, the developer of the present patent can obtain the effect of increasing the industrial applicability, while advantageous for mass production as a result.

That is, the manufacturing process of the present invention is

It is different from the manufacturing method of the prior art,

The cyclopentadienyl derivative compound used in that step is conveniently

manufacturing, separating high-purity products, etc.

It can be said that it is a more advanced method that has increased industrial applicability.

Hereinafter, the present invention will be described in more detail based on the following examples.

However, this is only to help the understanding of the configuration and operation of the present invention, and the scope of the present invention is not limited to these embodiments.

The present invention will be described in detail by the following examples.

Example 1: Preparation of N-methyl-1,3-cyclopentadiene-1-ethanamine (Formula 1, N-methyl-1,3-Cyclopentadiene-1-ethan amine, CpEMA )

After putting 1200 mL of aqueous solution into a three-neck flask connected to a thermometer, 178.3gr (3.5 equivalents) of potassium hydroxide was added at room temperature and dissolved at room temperature. The dissolved solution is cooled to 3-5 °C, and 60.0gr (0.98mol) of 1,3-cyclopentadiene is slowly added dropwise to dissolve. After adding 477 mL of aqueous solution to a three-neck flask connected to another reactor with a thermometer, 238.5gr (1.2 equivalents) of 2-bromo-N-methylethanamine bromate at room temperature was added and dissolved at room temperature. The dissolved 2-bromo-N-methylethanamine bromate aqueous solution was added dropwise to the pre-cooled reaction vessel for 30 minutes to proceed with the coupling reaction. When the dropwise addition is complete, the reaction solution is stirred for an additional 2 hours while maintaining 3-5 °C. After confirming the completion of the reaction using Gas Chromatography (GC), 300 mL of n-hexane was added to the reaction solution, stirred for 30 minutes, allowed to stand, and layer separated to form a side reaction material dicyclopentadiene (DCPD) is removed by transferring it to the upper layer. After maintaining the lower demand solution layer at 3~5℃, add 500mL of fresh n-hexane and acidify it using 3N hydrochloric acid solution. After adjusting the pH of the reaction solution to 2.5, the reaction solution is further stirred for 30 minutes and left still to separate the n-hexane layer. Anhydrous magnesium sulfate was added to the separated n-hexane solution to perform a dehydration reaction, followed by filtration and concentration under reduced pressure (3 to 5 torr) to obtain a clear oil phase.

The oil phase obtained above is subjected to fractional vacuum distillation using a high vacuum pump (0.2torr) to obtain a product distilled in the range of 30 to 33°C. The distilled product was 99.54% of the title compound 90.6gr as a white oil by gas chromatography analysis.

¹ H NMR (400 MHz, C6D ₆ ): 2.28(3H, s), 2.38~62(2H, m), 2.82(2H, m), 2.86(1H, m), 2.93(1H, m), 6.01(1H) , m), 6.19 (1H, m), 6.32 (1H, m), 6.44 (2H, m)

Example 2: Preparation of N-methyl-1,3-cyclopentadiene-1-ethanamine (Formula 1, N-methyl-1,3-Cyclopentadiene-1-ethan amine, CpEMA )

The potassium hydroxide equivalent used in Example 1 was changed to 4.5 equivalents, and the following reaction proceeds in the same manner, and 99.62% of the title compound 86..2gr was obtained by gas chromatography analysis.

Example 3: Preparation of N-methyl-1,3-cyclopentadiene-1-propanamine (Formula 2, N-methyl-1,3-Cyclo pentadiene-1-propanamine, CpPMA )

After putting 880 mL of aqueous solution in a three-neck flask connected to a thermometer, 133.7gr (3.5 equivalents) of potassium hydroxide was added at room temperature and dissolved at room temperature. The dissolved solution is cooled to 3-5 °C, and 45.0gr (0.98mol) of 1,3-cyclopentadiene is slowly added dropwise to dissolve. After putting 460 mL of aqueous solution in a three-necked flask connected to another reactor with a thermometer, 190.3gr (1.2 equivalents) of 2-bromo-N-methylpropylamine bromate was added at room temperature and dissolved at room temperature. The dissolved 2-bromo-N-methylpropylamine bromate aqueous solution was added dropwise to the pre-cooled reaction vessel for 30 minutes to proceed with the coupling reaction. When the dropwise addition is complete, the reaction solution is stirred for an additional 2 hours while maintaining 3-5 °C. After confirming the completion of the reaction using Gas Chromatography (GC), 280 mL of n-hexane was added to the reaction solution, stirred for 30 minutes, left still, and layer separated to form a side reaction material dicyclopentadiene (DCPD) is removed by transferring it to the upper layer. After maintaining the lower demand solution layer at 3~5℃, add 420mL of fresh n-hexane and acidify it using 3N hydrochloric acid solution. After adjusting the pH of the reaction solution to 2.5, the reaction solution is further stirred for 30 minutes and left still to separate the n-hexane layer. Anhydrous magnesium sulfate was added to the separated n-hexane solution to perform a dehydration reaction, followed by filtration and concentration under reduced pressure (3 to 5 torr) to obtain a clear oil phase.

The oil phase obtained above is subjected to fractional vacuum distillation using a high vacuum pump (0.2torr) to obtain a product distilled at 45±4°C. The distilled product is a light-off-white oily state of 99.65% of the title compound 71.0gr by gas chromatography analysis.

¹ H NMR (400 MHz, C ₆ D ₆ ): 1.50(12H, q), 1.68(2H, q), 2.20(3H, s), 2.34-2.50(4H, m), 2.74(2H, t), 5.98 (1H, m), 6.24 (2H, m), 6.38 (1H, m), 6.52 (2H, m)

Claims (3)

A method for preparing the following Chemical Formulas 1 and 2.

(1) N-methyl-1,3-cyclopentadiene-1-ethanamine compound of Formula 1
[Formula 1]

(2) N-methyl-1,3-cyclopentadiene-1-propanamine compound of Formula 2
[Formula 2]

The method according to claim 1, wherein the equivalent ratio of potassium hydroxide used in the reaction is 3.0 to 4.5 equivalents based on cyclopentadiene, preferably 3.5 equivalents. The ratio of distilled water to be dissolved is dissolved using 6.7 times the weight ratio in cyclopentadiene.
According to claim 1, wherein the amount of n-hexane used to remove the side reactant dicyclopentadiene (DCPD) is used in an amount of 5 times by weight to volume with respect to cyclopentadiene.