KR20190061877A - Method of depositing thin film - Google Patents

Abstract

The present invention relates to a method of depositing a thin film, which forms a silicon oxide film by repeatedly performing a unit cycle a plurality of times. The unit cycle comprises: a first process gas adsorption step of adsorbing first process gas containing a silicon precursor which includes an amine-based ligand on a substrate; a thin film forming step of forming a unit silicon oxide film on the substrate by supplying second process gas containing oxygen atoms which react with the first process gas adsorbed on the substrate; and a deposition control gas adsorption step of adsorbing, on the substrate, deposition control gas containing an amine-based inhibitor which has the same structure as the amine-based ligand.

Description

[0001] METHOD OF DELIVERING THIN FILM [0002]

The present invention relates to a thin film deposition method, and more particularly, to a method of depositing a silicon oxide film using an atomic layer deposition method.

Semiconductors are a combination of many electronic devices formed on a wafer. In the semiconductor manufacturing process, thin film deposition refers to a process of physically forming conductive, insulating, or semiconductor materials on a wafer. Representative methods for thin film deposition include an atomic layer deposition (ALD) method and a chemical vapor deposition (CVD) method. The CVD method is a method of depositing a thin film by reacting two gases, and can be subdivided into LPCVD (Low Pressure CVD) and PECVD (Plasma Enhanced CVD). The ALD method is a process for depositing atoms one layer at a time and can be used where a micronization process is more demanded. The design rule of a semiconductor device is continuously decreasing, and a thin film deposition method capable of satisfying the film characteristics required under these conditions is continuously required. Particularly, in the pattern having a step, difference in coating rate of the thin film formed on the upper and lower sides is a problem to be solved.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thin film deposition method capable of capturing without forming a seam in a pattern having a step difference to solve various problems including the above problems. However, these problems are illustrative and do not limit the scope of the present invention.

According to one aspect of the present invention, a thin film deposition method is provided. The thin film deposition method includes: a first process gas adsorption step of adsorbing a first process gas containing a silicon precursor including an amine-based ligand on a substrate; A thin film forming step of forming a unit silicon oxide film on the substrate by supplying a second process gas containing oxygen atoms reacting with the first process gas adsorbed on the substrate; And a deposition control gas adsorption step of adsorbing a deposition control gas containing an amine-based inhibitor having the same structure as the amine-based ligand on the substrate, have.

In the thin film deposition method, the silicon precursor is DIPAS (di (isopropyl) aminosilane), and the phosphorus is iPr2NH (di (isopropyl) amine), iPrNH2 (isoprophylamine), iPr3N (isoprophyl) amine and nPr3N (normalprophyl) amine).

In the thin film deposition method, the silicon precursor is BDEAS (diethylamino) silane, and the phosphorus atom may be at least one selected from Et2NH (Di (ethyl) amine) and Et3N (Tris (ethyl) amine).

In the thin film deposition method, the silicon precursor is 3DMAS (Tris (dimethylamino) silane), and the phosphorus atom may be at least one selected from Me2NH (Di (methyl) amine) and Me3N (Tris (methyl) amine).

In the thin film deposition method, the silicon precursor may be at least one selected from 4DMAS (Tetrakis (dimethylamino) silane), and the phosphorus is selected from Me2NH (Di (methyl) amine) and Me3N (Tris (methyl) amine).

In the thin film deposition method, the silicon precursor may be BTBAS (tertiarybutylamino) silane, and the phosphorous may be tBuNH2 (tertiarybutyl amine).

In the thin film deposition method, the unit cycle may sequentially include the first process gas adsorption step, the thin film formation step, and the deposition control gas adsorption step.

In the thin film deposition method, the unit cycle may sequentially include the deposition control gas adsorption step, the first process gas adsorption step, and the thin film formation step.

In the thin film deposition method, the unit cycle may further include purging and pumping steps between each of the deposition control gas adsorption step, the first process gas adsorption step and the thin film formation step.

In the thin film deposition method, the unit cycle may further include a step of pre-treating the substrate with a plasma containing at least one of N, O, and H on the substrate before the deposition control gas adsorption step.

In the thin film deposition method, the deposition control gas may be injected repeatedly in a pulse form in a plurality of times in the deposition control gas adsorption step.

In the thin film deposition method, the substrate has a step structure including a hole, a via hole, a contact hole or a trench, and the silicon oxide film is formed by filling the step structure by repeating the unit cycle a plurality of times, The deposition rate of the unit silicon oxide film can be controlled at the upper and lower portions of the step structure by controlling the regulating gas adsorption step.

In the thin film deposition method, the deposition rate at the upper portion of the step structure of the unit silicon oxide film deposited by performing the unit cycle including the first process gas adsorption step, the thin film formation step, and the deposition control gas adsorption step Of the unit silicon oxide film formed by performing the imaginary unit cycle including the first process gas adsorption step and the thin film forming step except for the deposition control gas adsorption step, It can be relatively slow.

In the thin film deposition method, the thickness of the unit silicon oxide film formed at the bottom of the step structure may be thicker than the thickness formed at the top of the step structure.

According to one embodiment of the present invention as described above, a seamless thin film deposition method capable of improving a coating rate in a pattern having a step difference can be realized. Of course, the scope of the present invention is not limited by these effects.

1 is a flowchart illustrating a unit cycle of an atomic layer deposition process in a thin film deposition method according to an embodiment of the present invention.
2 is a flowchart illustrating a unit cycle of an atomic layer deposition process in a thin film deposition method according to another embodiment of the present invention.
3 is a view illustrating a process of filling a step structure by a thin film deposition method according to an embodiment of the present invention.
4 is a graph illustrating the inhibitor is a deposition thickness of iPr2NH, the silicon precursor is DIPAS, the reaction gas is a silicon oxide film according to the injection time of the inhibitor in terms of O _3.
5 is a graph illustrating the inhibitor is a deposition thickness of iPr2NH, the silicon precursor is BDEAS, the reaction gas is a silicon oxide film according to the injection time of the inhibitor in terms of O _3.
Figure 6 is a graph illustrating the physisorption and chemisorption patterns of iPr2NH and Et2NH in order to examine the surface reaction.
FIG. 7A is a diagram illustrating the reaction energy and reaction process of the DIPAS source and Et2NH, and FIG. 7B is a diagram illustrating the reaction energy and reaction process of the DIPAS source and iPr2NH.
8 is a graph illustrating the inhibitor is a deposition thickness of Et2NH, the silicon precursor is BDEAS, the reaction gas is a silicon oxide film according to the injection time of the inhibitor in terms of O _3.
9 is a graph illustrating the inhibitor is a deposition thickness of Et2NH, the silicon precursor is DIPAS, the reaction gas is a silicon oxide film according to the injection time of the inhibitor in terms of O _3.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

It is to be understood that throughout the specification, when an element such as a film, an area, or a substrate is referred to as being "on" another element, the element may directly "contact" It is to be understood that there may be other components intervening between the two. On the other hand, when an element is referred to as being "directly on" another element, it is understood that there are no other elements intervening therebetween.

Hereinafter, embodiments of the present invention will be described with reference to the drawings schematically showing ideal embodiments of the present invention. In the figures, for example, variations in the shape shown may be expected, depending on manufacturing techniques and / or tolerances. Accordingly, the embodiments of the present invention should not be construed as limited to the particular shapes of the regions shown herein, but should include, for example, changes in shape resulting from manufacturing. Further, the thickness and the size of each layer in the drawings may be exaggerated for convenience and clarity of explanation. Like numbers refer to like elements.

The thin film described in the embodiments of the present invention can be understood as a thin film formed by ALD (Atomic Layer Deposition) which provides a small gas, a purge gas, a reactive gas, or the like on a substrate. The technical structure of the present invention is not limited to the time division mode in which the deposition is realized by supplying the source gas, the purge gas and the reaction gas or the like discontinuously in the chamber in which the substrate is disposed over time, The present invention can also be applied to a space division method in which deposition is realized by sequentially moving a substrate in a system continuously supplied while spaced apart.

The technical idea of the present invention is characterized by using an inhibitor for controlling the deposition rate of a silicon oxide film in an atomic layer deposition method of forming a silicon oxide film using a silicon precursor made of an amine-based ligand. The phosphorus-based phosphor includes an amine-based structure. In particular, the phosphorus-based phosphor has the same structure as the amine structure contained in the silicon precursor.

According to an aspect of the present invention, a thin film deposition method includes: a first process gas adsorption step of adsorbing a first process gas containing a silicon precursor including an amine-based ligand on a substrate; A thin film forming step of forming a unit silicon oxide film on the substrate by supplying a second process gas containing oxygen atoms reacting with the first process gas adsorbed on the substrate; A deposition control gas adsorption step of adsorbing a deposition control gas containing an amine-based inhibitor having the same structure as the amine-based ligand on the substrate; May be repeated a plurality of times.

The second process gas supplied onto the substrate in the thin film forming step for forming the unit silicon oxide film may be heated or in a plasma state.

In the thin film deposition method, in the deposition control gas adsorption step, the deposition control gas may be injected repeatedly in a pulse form a plurality of times. That is, the implantation method of the inhibitor may include a method of repeatedly injecting the wafer in a pulse form so as to be adsorbed well on the wafer surface or the silicon oxide film surface.

Further, in order to allow the inhibitor to be well adsorbed on the surface of the wafer or the silicon oxide film, the unit cycle may be performed by supplying a plasma containing at least one of N, O and H onto the substrate before the deposition control gas adsorption step (S150) And performing preprocessing using the above-mentioned method.

Meanwhile, in the thin film deposition method according to an embodiment of the present invention described above, additional thin film processing can be performed to remove impurities remaining in the thin film after the thin film deposition. Or further thin film processing may be performed to remove impurities remaining in the thin film between one unit cycle and another unit cycle while performing a plurality of unit cycles to deposit the thin film. The gas supplied in the additional thin film processing step may comprise one of H ₂ O, H ₂ O ₂ , O ₂ , O ₃ , NH ₃ , N ₂ H ₂ and H ₂ , It can be heated or in a plasma state.

Hereinafter, specific examples of the silicon precursor and the inhibitor will be described.

As a first example, the silicon precursor composed of an amine-based ligand may be DIPAS (di (isopropyl) aminosilane). In this case, an amine-based phosphorous compound having a homologous structure with an amine-based ligand constituting the silicon precursor at least one selected from the group consisting of iPr2NH (Di (isopropyl) amine), iPrNH2 (Isoprophylamine), iPr3N (Tris (isoprophyl) amine) and nPr3N (Tris (normalprophyl) amine).

As a second example, the silicon precursor made of an amine-based ligand is BDEAS (diethylamino) silane. In this case, the amine-based phosphorous compound having the same structure as that of the amine-based ligand constituting the silicon precursor may be Et2NH Di (ethyl) amine) and Et3N (Tris (ethyl) amine).

As a third example, the silicon precursor made of an amine-based ligand is 3DMAS (Tris (dimethylamino) silane). In this case, the amine-based phosphorous compound having the same structure as the amine-based ligand constituting the silicon precursor is Me2NH Di (methyl) amine) and Me3N (Tris (methyl) amine).

As a fourth example, a silicon precursor consisting of an amine-based ligand is 4DMAS (tetramethylsilane (TMA) (dimethylamino) silane). In this case, amine-type phosphorous compounds having the same structure as the amine- Di (methyl) amine) and Me3N (Tris (methyl) amine).

As a fifth example, the silicon precursor made of the amine-based ligand is Bis (tertiarybutylamino) silane (BTBAS). In this case, the amine-based phosphorous compound having the same structure as the amine-based ligand constituting the silicon precursor is tBuNH 2 Tertiarybutyl amine).

The unit cycle of the atomic layer deposition process in the thin film deposition method according to the present invention can be variously configured.

1 is a flowchart illustrating a unit cycle of an atomic layer deposition process in a thin film deposition method according to an embodiment of the present invention. Referring to FIG. 1, the unit cycle S100 includes a first process gas adsorption step (S110), a thin film formation step (S130), and a deposition control gas adsorption step (S150). The detailed description of each step is replaced with the one described above. The unit cycle S100 includes purging and pumping steps S120, S140, and S160 between the first process gas adsorption step S110, the thin film formation step S130, and the deposition control gas adsorption step S150, As shown in FIG.

 2 is a flowchart illustrating a unit cycle of an atomic layer deposition process in a thin film deposition method according to another embodiment of the present invention. Referring to FIG. 2, the unit cycle S200 includes a deposition control gas adsorption step (S210), a first process gas adsorption step (S230), and a thin film formation step (S250). The detailed description of each step is replaced with the one described above. The unit cycle S200 includes purging and pumping steps S220, S240 and S260 between the deposition control gas adsorption step S210, the first process gas adsorption step S230 and the thin film formation step S250, As shown in FIG.

On the other hand, the purging step shown in FIGS. 1 and ₂ may include purging with an inert gas (e.g., N ₂ ). The inert gas may be at least any one of nitrogen (N ₂₎ in addition to helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn). On the other hand, the inert gas can be continuously supplied into the chamber even during a unit cycle. In this case, the inert gas may also serve as a carrier gas.

The thin film deposition method according to the embodiment of the present invention described above can be applied on a substrate having a stepped structure.

3 is a view illustrating a process of filling a step structure by a thin film deposition method according to an embodiment of the present invention.

Referring to FIG. 3, the substrate 10 has a stepped structure including a hole, a via hole, a contact hole, or a trench. The unit cycle of the atomic layer deposition method described above is repeated a plurality of times to form the silicon oxide film while filling up the stepped structure. In particular, the deposition rate of the unit silicon oxide film can be controlled at the upper and lower portions of the step structure by controlling the deposition control gas adsorption step of the unit cycle. That is, the deposition rate of the unit silicon oxide film is controlled by using a silicon precursor composed of an amine-based ligand and an inhibitor identical to the amine structure contained in the silicon precursor as a deposition control gas.

Referring to the graph of FIG. 3, the horizontal axis represents the number of repetitions of the unit cycle of the atomic layer deposition process, and the vertical axis represents the thickness of the silicon oxide film. Line B relates to a silicon oxide film treated with an inhibitor as an embodiment of the present invention (On inhibitor-treated SiO2; Seamless ALD), and the A line relates to a silicon oxide film not treated with an inhibitor as a comparative example.

As a result, in the embodiment of the present invention, the deposition rate at the bottom of the pattern of the step structure is relatively increased, thereby eliminating the overhang on the pattern or reducing the high aspect ratio caused by narrowing the entrance A gap fill process without seam becomes possible.

In the thin film deposition method, the deposition rate at the upper portion of the step structure of the unit silicon oxide film deposited by performing the unit cycle including the first process gas adsorption step, the thin film formation step, and the deposition control gas adsorption step Of the unit silicon oxide film formed by performing the imaginary unit cycle including the first process gas adsorption step and the thin film forming step except for the deposition control gas adsorption step, It can be relatively slow.

In some cases, in the thin film deposition method, the unit silicon oxide film 20 may have a thickness 21 formed at a lower portion of the step structure, which is thicker than thicknesses 22 and 23 formed at an upper portion of the step structure.

Hereinafter, exemplary experiments will be described in order to facilitate understanding of the present invention. It should be understood, however, that the following examples are intended to aid in the understanding of the present invention and are not intended to limit the scope of the present invention.

Figure 4 is an inhibitor that iPr2NH, the silicon precursor is DIPAS, reaction gas O ₃ is a graph showing the deposition thickness of the silicon oxide film according to the injection time of the inhibitor in the condition, Figure 5 is the inhibitor is iPr2NH, the silicon precursor BDEAS And the thickness of the silicon oxide film according to the injection time of the inhibitor under the condition that the reaction gas is O ₃ .

In this experiment, in the deposition of a silicon oxide film by repeating a unit cycle 50 times in an atomic layer deposition system using a DIPAS (Diisopropylamino silane) silicon precursor and a reaction gas at a process temperature of 200 ° C. using O ₃ , Likewise, a step of injecting iPr2NH (diisopropyl amine), an inhibitor having the same atomic structure as the ligand of the DIPAS source, was performed in every unit cycle. The injected phosphorous is adsorbed on the surface of the film and controls the deposition rate by interfering with the subsequent surface adsorption of DIPAS. As shown in the graph of FIG. 4, it can be seen that as the feeding time of iPr2NH increases from 0 seconds to 5 seconds, the deposition thickness decreases. On the other hand, as shown in Fig. 5, when the iPr2NH was used as the inhibitor and the BDEAS was used as the silicon precursor, no reduction effect was observed.

Hereinafter, iPr2NH and Et2NH are compared with respect to the DIPAS source, and it is examined whether or not any substance is suitable as an inhibitor.

Figure 6 is a graph illustrating the physisorption and chemisorption patterns of iPr2NH and Et2NH in order to examine the surface reaction. Referring to FIG. 6, it can be seen that the iPr2NH and Et2NH hydrocarbons predominate in physical adsorption rather than chemical adsorption.

FIG. 7A is a diagram illustrating the reaction energy and reaction process of the DIPAS source and Et2NH, and FIG. 7B is a diagram illustrating the reaction energy and reaction process of the DIPAS source and iPr2NH.

Referring to FIG. 7A, it can be understood that Et2NH does not act as an inhibitor as it falls through the reaction with DIPAS (? E: -0.372 eV). Referring to FIG. 7B, it can be understood that iPr2NH plays a role of inhibition due to a small reaction (ΔE: -0.075 eV) with DIPAS. From this, it can be seen why only iPr2NH acts as an inhibitor in the DIPAS source.

FIG. 8 is a graph showing the deposition thickness of a silicon oxide film according to the time of injection of an inhibitor in the condition that the inhibitor is Et 2 NH, the silicon precursor is BDEAS, and the reaction gas is O _3. FIG. 9 is a graph showing the deposition thickness of Et 2 NH, And the thickness of the silicon oxide film according to the injection time of the inhibitor under the condition that the reaction gas is O ₃ .

In the case of using silicon dioxide using BDEAS (Bdiasteramino silane) and O ₃ at the process temperature of 400 ° C., when Et 2 NH (Diethylamine) is used as an inhibitor, the silicon oxide film thickness increases with increasing Et 2 NH feeding time (Fig. 8). On the other hand, when Et2NH and DIPAS silicon precursor were used as inhibitors, no effect of reducing the thickness was observed (FIG. 9). The mechanism by which only Et2NH acts as an inhibitor in the BDEAS source is the same as the mechanism of the iPr2NH inhibitor and DIPAS source described above.

The technical idea of the present invention using this mechanism is the use of an inhibitor for controlling the deposition rate of the silicon oxide film in the atomic layer deposition method of forming a silicon oxide film using a silicon precursor comprising an amine series ligand, The term " amide structure " includes amines of the amine structure, and particularly, the same amine structure as the silicon precursor is used as the inhibitor.

The present invention provides an exemplary combination of a silicon precursor and an inhibitor by the above-described mechanism. As a first example, a silicon precursor comprising an amine series ligand may be DIPAS (di (isopropyl) aminosilane) In this case, the amine precursors having the same structure as the amine-based ligands constituting the silicon precursor are selected from the group consisting of iPr2NH (Di (isopropyl) amine), iPrNH2 (Isoprophylamine), iPr3N (Tris (isoprophyl) amine) and nPr3N and the silicon precursor is a BDEAS (diethylamino) silane. In this case, the amine precursor may be at least one selected from the group consisting of amine-based ligands And an amine-based phosphorous compound having a homogeneous structure may be at least one selected from Et2NH (Di (ethyl) amine) and Et3N (Tris (ethyl) amine) The amine precursor of the amine type having a structure homologous to the amine-based ligand constituting the silicon precursor is Me2NH (di (methyl) amine) and In the fourth example, the silicon precursor composed of an amine-based ligand is tetramethylsilane (TDM) (tetramethylsilane). In this case, the silicon precursor may be at least one selected from the group consisting of The amine-based phosphorus ligand having the same structure as the amine-based ligand may be at least one selected from the group consisting of Me2NH (Di (methyl) amine) and Me3N (Tris (methyl) amine) Is a BTBAS (tertiarybutylamino) silane. In this case, the silicon precursor is an amine-based one having a homologous structure with an amine-based ligand constituting the silicon precursor The inhibitor may be tBuNH2 (Tertiarybutyl amine).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (12)

A first process gas adsorption step of adsorbing a first process gas containing a silicon precursor including an amine-based ligand on a substrate;
A thin film forming step of forming a unit silicon oxide film on the substrate by supplying a second process gas containing oxygen atoms reacting with the first process gas adsorbed on the substrate; And
A deposition control gas adsorption step of adsorbing a deposition control gas containing an amine-based inhibitor having the same structure as the amine-based ligand on the substrate;
And a plurality of unit cycles,
Thin film deposition method. The method according to claim 1,
The silicon precursor is DIPAS (di (isopropyl) aminosilane)
Wherein the phosphorus atom is at least one selected from the group consisting of iPr2NH (Di (isopropyl) amine), iPrNH2 (Isoprophylamine), iPr3N (Tris (isoprophyl) amine) and nPr3N (Tris (normalprophyl)
Thin film deposition method. The method according to claim 1,
The silicon precursor is BDEAS (bis (diethylamino) silane)
Wherein the phosphorus atom is at least one selected from the group consisting of Et2NH (Di (ethyl) amine) and Et3N (Tris (ethyl) amine)
Thin film deposition method. The method according to claim 1,
The silicon precursor is 3DMAS (Tris (dimethylamino) silane)
Wherein the phosphorus atom is at least one selected from the group consisting of Me2NH (Di (methyl) amine) and Me3N (Tris (methyl) amine)
Thin film deposition method. The method according to claim 1,
The silicon precursor is 4DMAS (Tetrakis (dimethylamino) silane)
Wherein the phosphorus atom is at least one selected from the group consisting of Me2NH (Di (methyl) amine) and Me3N (Tris (methyl) amine)
Thin film deposition method. The method according to claim 1,
The silicon precursor is BTBAS (tertiarybutylamino) silane,
The inhibitor is tBuNH2 (Tertiarybutylamine)
Thin film deposition method. The method according to claim 1,
Wherein the unit cycle includes the first process gas adsorption step, the thin film formation step, and the deposition control gas adsorption step,
Thin film deposition method. The method according to claim 1,
Wherein the unit cycle includes the deposition control gas adsorption step, the first process gas adsorption step, and the thin film formation step in sequence.
Thin film deposition method. 9. The method according to claim 7 or 8,
Wherein said unit cycle further comprises purging and pumping between each of said deposition regulating gas adsorption step, said first process gas adsorption step and said thin film forming step.
Thin film deposition method. The method according to claim 1,
Wherein the unit cycle further comprises pretreating the substrate with a plasma containing at least one of N, O and H on the substrate before the deposition control gas adsorption step.
Thin film deposition method. The method according to claim 1,
Wherein the deposition control gas is injected in a pulse form repeatedly a plurality of times in the deposition control gas adsorption step.
Thin film deposition method. The method according to claim 1,
Wherein the substrate has a step structure including a hole, a via hole, a contact hole or a trench, the silicon oxide film being formed by filling the step structure by repeating the unit cycle a plurality of times, And the deposition rate of the unit silicon oxide film is controlled at the upper and lower portions of the step structure.
Thin film deposition method.

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