KR20090020075A - Thin film manufacturing method using organometallic compound for semiconductor device thin film - Google Patents

Abstract

The present invention relates to a method for manufacturing an organometallic thin film by chemical vapor deposition using the organometallic compound of Formula 1 or Formula 2, the organometallic compound of the present invention can be deposited at a low temperature, has a high deposition rate It is stable in the air, and the thin film can be efficiently manufactured using the processes of atomic layer deposition and organometallic chemical vapor deposition (MOCVD).

[Formula 1]

[Formula 2]

Where

M is Pb, Zr or Ti, and R '

R ₁ , R ' ₁ , R ₂ , R' ₂ , R ₃ , R ' ₃ and R _{4 ,} R' ₄ are each independently H or C ₁ to C ₄ alkyl,

m, m 'and n are each independently an integer of 1-5.

Description

Thin film manufacturing method using organometallic compound for thin film semiconductor device {Organometallic Precursor for Ferroelectric RAM and Deposition Method of thin film}

1 shows an NMR graph of Pb (mop) n prepared in Example 1 used of the present invention;

2 shows an NMR graph of Zr (mop) ₄ prepared in Example 2 used of the present invention;

3 is an NMR graph of Ti (mop) ₄ prepared in Example 3 used of the present invention;

4 is an NMR graph of Ti (moe) ₄ prepared in Example 3 used of the present invention;

5 shows a TA graph of (Pb (mop) ₂ ) n prepared in Example 1 used of the present invention;

6 shows a TA graph of Zr (mop) ₄ prepared in Example 2 used of the present invention;

7 shows a TA graph of Ti (mop) ₄ prepared in Example 3 used of the present invention;

8 shows a TA graph of Ti (moe) ₄ prepared in Example 4 used of the present invention;

9 is a VT-NMR graph of (Pb (mop) ₂ ) n, Zr (mop) ₄ , Ti (mop) ₄ , Ti (moe) ₄ prepared in Examples 1, 2, 3, and 4 of the present invention. Represent;

10 is a TA graph of Zr (i-PrO) ₃ (thd) 1 Zr (thd) ₄ as used conventionally;

11 is a TA graph of Ti (i-PrO) ₂ (thd) ₂ used in the related art.

FIG. 12 shows a TA graph in solution of (Pb (mop) ₂ ) n with a particular solvent (octane) prepared in Example 1 used of the present invention; FIG.

FIG. 13 shows a TA graph in solution with a specific solvent (octane) of Zr (mop) ₄ prepared in Example 2 used of the present invention; FIG.

FIG. 14 shows a TA graph in solution with a specific solvent (octane) of Ti (mop) ₄ prepared in Example 3 used of the present invention; FIG.

15 is a graph showing a change in deposition rate of a single oxide film according to the substrate temperature in the present invention;

16 is a graph comparing the deposition rate between a conventional red precursor (circle: Pb (TMHD) ₂ ) and the red precursor used in the present invention;

17 is a graph comparing the deposition rate between a conventional zirconium precursor (circle: Zr (METHD) ₄ and the zirconium precursor used in the present invention);

FIG. 18 is a graph comparing deposition rates between a conventional titanium precursor (circle: Ti (TMHD) ₂ MPD) and a titanium precursor used in the present invention; FIG.

19 is a graph of leakage current characteristic evaluation according to the molar ratio of zirconium / titanium in the present invention;

20 is a graph showing deposition rate according to substrate temperature in the present invention;

21 is a surface analysis photograph according to the molar ratio of zirconium / titanium in the present invention.

The present invention relates to a method for manufacturing an organic compound thin film for a semiconductor device using the organometallic compound of Formula 1 or 2, it can be prepared by the organometallic chemical vapor deposition method and atomic deposition method.

Recently, the development of semiconductor technology has continued to grow by pursuing more advanced technology through miniaturization of semiconductor devices, and research on suitable thin film materials and process technologies is actively being conducted.

In particular, barium strontium titanate (BST) used in capacitors for dynamic random access memory (DRAM) in semiconductor processes, lead zirconate titanate (PZT) applied to ferroelectric random access memory (FRAM), In addition to strontium bismuth titanate (SBT) and bismuth lanthanum titanate (BLT), oxide thin film manufacturing processes such as Yttrium stabilized zirconia (YSZ), TiO ₂ , and ZrO ₂ have been studied.

Examples of the ferroelectric and oxide thin film manufacturing methods include RF magnetron sputtering, ion beam sputtering, reactive co-evaporation, metal organic decomposition, and MOD. Liquid Source Misted Chemical Decomposition (LSMCD), Laser Ablation, and Metal Organic Chemical Vapor Deposition (MOCVD) have been developed.

Among these, organometallic chemical vapor deposition (MOCVD) and atomic vapor deposition (ALD) are processes for vaporizing gaseous raw materials, that is, organometallic precursor compounds, and then synthesizing a desired solid material thin film by chemical reaction. The formation process of the thin film can be controlled.

In general, since the decomposition temperature of the organometallic compound is low, a low temperature process is possible, and the composition and deposition rate of the thin film can be controlled by controlling the introduction amount of the raw material and the transport gas amount, and the large area uniformity is good. It can be applied to a large scale process and can obtain a thin film having excellent step coverage without damaging the surface of the substrate.

For this reason, attention is focused on the MOCVD process for producing excellent thin films in semiconductor processes.

Generally required CVD precursors (complexes) should be characterized by high vapor pressure, high purity, low temperature deposition, high deposition rate, high purity thin film deposition, ease of handling, non-toxicity, low cost, wide deposition temperature. .

To date, metal organic compounds used to deposit metal oxide thin films can be classified into alkyl metals, metal alkoxides, and β-diketonate systems.

However, alkyl metal precursors (complexes) such as Pb (C ₂ H ₅ ) ₄ have a large disadvantage (reference of organometallic dictionary, alkoxides) due to high vapor pressure of raw materials but toxic and explosive properties. It is relatively easy and the decomposition process is well studied, but it is very sensitive to moisture, so that hydrolysis or hydration reaction occurs easily.

In addition, β-diketonate-based precursors (complexes), which are widely used, are not sensitive to moisture and are easy to handle, but are difficult to synthesize in high purity, and exist in a solid phase at room temperature. The disadvantage is the high price (Anthony C. Jones et al., Journal of the European Ceramic Society , 19 (1999), 1431-1434).

In addition, conventionally used Ti (i-OPr) ₄ (i-OPr = iso-propoxide) has an unstable disadvantage at room temperature, in the case of Ti (i-OPr) ₂ (thd) ₂ (thd = tetramethylheptanedionate) There is a problem in that the Ti content is largely changed according to the temperature change in manufacturing the Ti thin film, and it is difficult to apply to the low temperature pyrolysis process required in the manufacturing process of the semiconductor device. Moreover, in the case of Ti (i-OPr) ₂ (thd) ₂ , the weaker Ti- (i-OPr) bonds are separated first, thereby causing two or more molecules to bond, resulting in uneven Ti in the thin film. There was a problem with distribution (see Electrochemical and Solid - State Letters , 2 (10) (1999), 507-509).

Accordingly, an object of the present invention is to solve the problems described above, thermally stable, not sensitive to moisture, non-toxic, exist in the liquid phase at room temperature, easy to handle and vapor deposition, performing a deposition process using a new inexpensive organic metal compound It is to provide an optimization process for obtaining high quality thin film.

The present invention dilutes the organometallic compound of Formula 1 or Formula 2 to 0.1 to 0.01 M in an organic solvent, and injects a process gas of 50 sccm to 4000 sccm under a vaporizer temperature of 220 ° C. to 240 ° C. to a substrate temperature of 360 ° C. to 420 ° C. The present invention relates to a method for manufacturing a thin film for a semiconductor device by organometallic chemical vapor deposition (MOCVD).

Where

M is Pb, Zr or Ti, and R '

R ₁ , R ' ₁ , R ₂ , R' ₂ , R ₃ , R ' ₃ and R _{4 ,} R' ₄ are each independently H or C ₁ to C ₄ alkyl,

m, m 'and n are each independently an integer of 1-5.

The present invention is preferably characterized in that the organic solvent is an octane solution.

In addition, the present invention, the organometallic precursor is preferably (Pb (mop) ₂ ) n (Lead bis 1-methoxy-2-propoxide), represented by the following formula 3 to 5, Zr (mop) ₄ (zirconium tetra 1-methoxy-2-propoxide) or Ti (mop) ₄ (titanium tetra 1-methoxy-2-propoxide ))to be.

Where n is an integer of 1, 2, 3, 4 or 5

In addition, the present invention is characterized in that the semiconductor device thin film is a PbO, ZrO ₂ or TiO ₂ or a PZT thin film as a single metal thin film.

Preferably, in the preparation of the PZT thin film, the organometallic compound is characterized by a Zr / Ti molar ratio of 0.6 to 0.8 with respect to Pb 1 based on the molar ratio.

In addition, the process gas is characterized in that the value of oxygen / (oxygen + argon) is 0.5 ~ 0.6.

The organometallic compound of the present invention using the organometallic compound of Formula 1 or Formula 2 is the deposition temperature of the substrate temperature from 300 ℃ to 450 ℃ and the deposition pressure is from 1 tor to 2 tor,

The feed gas flow rate is 50 sccm to 400 sccm, a direct solution supply system process is applied, the solvent used is octane, and the vaporization temperature is preferably 200 ° C. to 250 ° C. The content ratio of zirconium / titanium is 0.6 to 0.8 and the amount of organometallic compound supplied to the vaporization apparatus is 0.15 ml / min to 0.20 ml / min, and the substrate is a thin film deposition method for depositing a thin film using Pt and Ir electrodes. It is about.

Preferably the metal-containing thin film is characterized by lead zirconate titanate.

The organometallic deposition method of the present invention is a bubbling transport method that generally uses an organometallic precursor (which is advantageous because the compound is a liquid; the bubbling method is well implemented without particular limitations; transported in a container containing a liquid) Gases can be produced using liquids (= precursors (complexes), organometallic precursors, and gases containing compounds to the reactor), or liquid delivery (precursors (complexes) (organic metal complexes) A method of depositing a metal-containing thin film is provided using a method of continuously injecting a solution into a vaporizer and vaporizing the vaporizer in a vaporizer.

Hereinafter, the present invention will be described in detail.

The organometallic compounds used in the present invention can be obtained by reacting a red, titanium or zirconium compound with an amine compound providing the corresponding ligand.

As the red, titanium or zirconium compound in the reaction, red bis diethylamine, titanium tetradiethylamine, zirconium tetradiethylamine, titanium tetraalkoxide, zirconium tetraalkoxide, etc., which are compounds of Formula 6 or 7, may be used. As an amine compound, dimethylpropanolamine, dimethylethanolamine, etc. are preferable.

M (NR ₂ ) _x

M (OR ') ₄

Wherein R and R 'are each independently C _y H2 _{y +1} , y is an integer from 1 to 3, and R and R' also include possible isomers. x is 2 or 4.

As the reaction solvent, conventional organic solvents such as nucleic acid, toluene and pentane can be used. The reaction ratio of the red, titanium or zirconium compound and the amine is preferably 1: 2, 1: 4 to 1: 5, and when the mixture is stirred at reflux for 15 to 20 hours, a pure compound is obtained with a high yield of 90% or more.

The organometallic compound is present in the liquid phase at room temperature, is easy to handle, and has excellent vaporization properties even at low temperatures, and thus is suitable as a precursor in the manufacture of thin films for semiconductor devices.

For example, zirconium or titanium oxide thin films may be deposited using conventional organic chemical vapor deposition methods (see Anthony C. Jones et al., Chemical Vapor Deposition, 4 (2) (1998), 46-49). , Barium strontium titanate (BST) ( Electrochemical and Solid - State Letters , 2 (10) (1999), 507-509), lead zirconate titanate (PZT) (Anthony C. Jones et al., Journal of the European Ceramic Society , 19 (1999), 1431-1434), strontium bismuth titanide (SBT) (see C. Isobe et al., Integrated Ferroelectrics , 14 (1999), 95-103), bismuth lanthanum titanate (BLT) or yttrium stabilized zirconia (YSZ) (C. Dubourdieu et al., Thin Solid Films , 339 (1999), 165-173).

Substrates that can be used in the present invention include those used in conventional semiconductor device manufacturing processes, such as substrates coated with various materials (Pt, Ir, IrO ₂ , Ru, RuO ₂ , SrRuO _3, etc.) on silicon and silicon.

Hereinafter, the present invention will be described in detail with reference to Examples and Test Examples. The following examples or test examples are merely illustrative for the purpose of describing the present invention, but the technical spirit of the present invention is not limited thereto or changed by the present invention.

Example  One  : ( Pb ( mop ) ₂ Production of n (1)

Pb (NEt2) 2 (redbisdiethylamine) (10 g, 28.5 mmol) was completely diluted by the addition of anhydrous hexane (100 ml) little by little, followed by the slow dropwise addition of methoxypropanol (5.13 g, 57 mmol). The temperature was slowly raised (80 ° C.) to reflux for 20 hours, and after cooling, the solvent was removed under vacuum to obtain a red yellow liquid (10.2 g) (yield> 90%).

The TA graph of the prepared (Pb (mop) ₂ ) n is shown in FIG. 5.

¹ H NMR (C ₆ D ₆ 400 MHz): δ5.15 (m, CH, 2H), δ 3.45 (m, CH ₂ , 2H), δ3.32 (m, CH ₂ , 2H), δ3.20 ( s, CH ₃ , 6H), δ1.39 (d, CH ₃ , 6H)

Example  2  : Zr ( mop ) ₄ Manufacture

(1) Zr (NEt ₂ ) ₄ (zirconium detradiethylamine) (10 g, 26 mmol) was added to anhydrous nucleic acid (100 ml) little by little and completely diluted, and then methoxy propane (9.5 g, 105 mmol) was slowly added dropwise. The temperature was slowly raised (80 ° C) to reflux for 20 hours, and after cooling, the solvent was removed under vacuum to obtain a pale yellow liquid (10.7 g) (yield> 90%). (Pb (mop) ₂ ) n

The TA graph of Zr (mop) ₄ prepared above is shown in FIG. 6.

¹ H NMR (400 MHz, C ₆ D ₆ ): δ 4.57 (m, CH, 4H), δ 3.57 (m, CH ₂ , 8H), δ3.33 (s, CH ₃ , 12H), δ1.42 (m, CH ₃ , 12H)

(2) ZrCl ₄ (zirconium detraclide) (10 g, 42.9 mmol) was added to anhydrous ethyl ether (100 ml) little by little and completely diluted, followed by triethylamine (17.36 g, 171.6 mmol) and methoxy propane (15.45, 171.6 mmol) was slowly added dropwise. After 20 hours of reaction at room temperature, the by-products were removed, dried in vacuo, filtered by dropwise addition of hexane (100 ml), and the solvent was removed under vacuum to obtain a pale yellow liquid (16.1 g) (yield> 80%).

Example  3  : Ti ( mop ) ₄ Manufacture

(1) Ti (OiPr) ₄ (titanium tetraisopropoxide) (10 g, 35.2 mmol) was added to anhydrous hexane (100 ml) little by little, completely diluted, and then methoxy propane (12.7 g, 141 mmol) was slowly added dropwise. The temperature was slowly raised (80 ° C.) to reflux for 15 to 20 hours, then cooled, and the solvent was removed in vacuo. The resulting colorless liquid was distilled at 150 ° C. to give a colorless liquid (11.4 g) (yield> 80%).

The TA graph of the prepared Ti (mop) ₄ is shown in FIG.

¹ H NMR (400 MHz, C ₆ D ₆ ): δ4.72 (m, CH, 4H), δ3.45 (m, CH ₂ , 8H), δ3.32 (s, CH ₃ , 12H), δ1.22 (m, CH ₃ , 12H)

(2) Ti (NEt ₂ ) ₄ (titanium tetradiethylamine) (10 g, 29.7 mmol) was added to anhydrous hexane (100 ml) little by little, followed by complete dilution, and methoxy propanol (10.8 g, 119 mmol) was slowly added dropwise. The temperature was slowly raised (80 degrees) to reflux for 20 hours, and after cooling, the solvent was removed under vacuum to obtain a colorless liquid (11.2 g) (yield> 90%).

Example  4  : Ti ( moe ) ₄ Manufacture

(1) Ti (i-OPr) ₄ (titanium tetraisopropoxide) (10 g, 35.2 mmol) was added to the nucleic acid (100 ml) little by little, completely diluted, and methoxyethanol (10.7 g, 141 mmol) was slowly added dropwise. The temperature was slowly raised (80 ° C) to reflux for 15 to 20 hours , and after cooling, the solvent was removed under vacuum to obtain a colorless liquid, which was distilled to give a yellow liquid (10.2 g) (yield> 80%).

The TA graph of the prepared Ti (moe) 4 is shown in FIG. 8.

¹ H NMR (400 MHz, C ₆ D ₆ ): δ4.60 (t, CH ₂ , 8H), δ3.58 (t, CH ₂ , 8H), δ3.29 (s, CH ₃ , 12H)

(2) Ti (NEt ₂ ) ₄ (titanium tetradiethylamine) (10 g, 29.7 mmol) was added to anhydrous hexane (100 ml) little by little, followed by complete dilution, and methoxyethanol (9.03 g, 119 mmol) was slowly added dropwise. The temperature was slowly raised (80 ° C) to reflux for 20 hours, and after cooling, the solvent was removed under vacuum to obtain a colorless liquid (9.9 g) (yield> 90%).

Test Example  One  : Thermal stability  exam

9 is an NMR spectrum of (Pb (mop) ₂ ) n, Zr (mop) ₄ , Ti (mop) ₄ , Ti (moe) ₄ prepared in Examples 1, 2, 3, and 4 at −25 ° C. FIG. The result measured and the result measured at 60 degreeC are shown the same. Therefore, it can be seen that the organometallic precursor according to the present invention is thermally stable.

Test Example  2  : Vaporization temperature  analysis

10 is Zr (i-OPr) ₃ (thd) ((2,2,6,6-titramethyl-3,5-heptanedion) tree of Formula 8, which is a conventional diketonate precursor (complex) TGA graph of (isopropoxide) zirconium) (solid line) and Zr (thd) ₄ (tetra (2,2,6,6-tetramethyl-3,5-heptanedion) zirconium (dotted line) It is shown.

In general, the precursor (complex) used in the manufacture of a thin film for semiconductor devices preferably has a property of vaporizing at 200 to 260 ° C., which is the organometallic precursor according to the present invention (Pb (mop) ₂ ) n, Zr ( mop) ₄ , Ti (mop) ₄ , Ti (moe) ₄ exhibited a vaporization behavior at 200 to 260 ° C., as shown in FIGS. 5, 6, 7, and 8, and is suitable as a precursor (complex) for thin film manufacturing. It can be seen. On the other hand, in FIG. 9, when the TGA graphs of Zr (i-OPr) ₃ (thd) (solid line) and Zr (thd) ₄ (dashed line), which are conventional diketonate precursors (complexes), are Zr (thd) ₄ In case of (dotted line), it shows poor behavior that vaporization starts after 350 ° C. In case of Zr (i-OPr) ₃ (thd) (solid line), the vaporization temperature is low, but the compound itself is solid at room temperature, so the thin film manufacturing process Inconvenient handling is disadvantageous. Thus, it can be seen that the precursor (complex) of the present invention is more suitable for use in the thin film deposition process.

Test Example 3  : Single Film Thin Film Deposition

The deposition rates of PbO, ZrO ₂ and TiO ₂ according to the deposition temperature of the substrate using the organometallic compound prepared in Example are shown in FIG. 15. At this time, the concentration of the organometallic compound is 0.05M, 0.15ml / min (in octane) and the vaporizer temperature is preferably 240 ℃.

Test Example  4  : PZT  Thin film deposition

The Zr / Ti ratio is 0.8 and the vaporizer temperature is 240 ° C. at the deposition temperature of 410 ° C. using the organometallic compound prepared in Example. At this time, the concentration of the organometallic compound is 0.05M, 0.15ml / min (in octane) and the oxygen supply amount is preferably 300sccm ((oxygen / oxygen + arcon) = 0.55). The deposition rate according to the substrate temperature change is shown in FIG. 21.

As described above, the thin film deposition process was performed by using the synthesized organometallic compound, and the content of impurities which may be commonly observed in the low temperature process was insignificant, and the residual polarization value was obtained as 21 μC / cm ² . The present invention can provide optimum process conditions in performing the thin film deposition process using the synthesized organometallic compound.

Claims (6)

Dilute the organometallic compound of Formula 1 or Formula 2 to 0.1 to 0.01 M in an organic solvent, inject a process gas of 50 sccm to 4000 sccm under a vaporizer temperature of 220 ° C. to 240 ° C. A method for producing a thin film for semiconductor devices by chemical vapor deposition (MOCVD).

(I)

(Ⅱ) Where M is Pb, Zr or Ti, and R ' R ₁ , R ' ₁ , R ₂ , R' ₂ , R ₃ , R ' ₃ and R _{4 ,} R' ₄ are each independently H or C ₁ to C ₄ alkyl, m, m 'and n are each independently an integer of 1-5. The method of claim 1, The organic solvent is a thin film manufacturing method for a semiconductor device, characterized in that the octane solution. The organometallic compound of Formula 1 or 2 according to claim 1 (Pb (mop) ₂ ) n (Lead bis 1-methoxy-2-propoxide) represented by the following formula 3 to 5 Zr (mop) ₄ (zirconium tetra 1-methoxy-2-propoxide) or Ti (mop) ₄ (titanium tetra 1-methoxy-2- thin film manufacturing method for a semiconductor device, characterized in that (propoxide)). [Formula 3]

Where n is an integer of 1, 2, 3, 4 or 5 [Formula 4]

[Formula 5]

The method of claim 1, wherein the semiconductor device thin film is one selected from PbO, ZrO 2, TiO 2, or PZT thin film. The method of claim 4, wherein the PZT thin film has a molar ratio of the organometallic compound having a Zr / Ti molar ratio of 0.6 to 0.8 with respect to Pb 1. The method of claim 1, wherein the process gas has an oxygen / (oxygen + argon) value of 0.5 to 0.6.

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