KR100719805B1 - Method of depositing capacitor electrode adding transition metal - Google Patents

Abstract

The present invention relates to a semiconductor thin film deposition method, and more particularly to a capacitor electrode deposition method.

The electrode deposition method according to the present invention comprises the steps of (a) supplying a capacitor electrode source and a transition metal source into the chamber and depositing it on a substrate provided in the chamber; (b) supplying a gas into a chamber to form the gas atmosphere; (c) densifying the thin film deposited in step (a) by applying a plasma of the same kind as the gas supplied in step (b); (d) purging to remove by-products generated in step (c); And (e) repeating steps (a) to (d).

In the method of depositing a capacitor electrode with a transition metal according to the present invention, by adding a transition metal during deposition of a capacitor electrode, it is possible to deposit a thin film having excellent surface morphology by improving electrical and physical properties of the capacitor electrode thin film. Even after the heat treatment, a capacitor electrode thin film having excellent surface roughness can be provided.

Transition metal, surface roughness, thin film deposition

Description

Method for depositing capacitor electrode with transition metal {Method of depositing capacitor electrode adding transition metal}

1 is a view showing a capacitor electrode deposition method to which a transition metal is added according to the present invention.

2 is a view showing a deposition method using the ALD method of the capacitor electrode deposition method to which the transition metal is added according to the present invention.

Figure 3a is a view showing an embodiment of a capacitor electrode deposition method to which a transition metal is added according to the present invention.

Figure 3b is a view showing another embodiment of the capacitor electrode deposition method to which the transition metal is added according to the present invention.

4 shows the results of component analysis (AES) inside ruthenium capacitor electrodes formed by one embodiment of the method of the present invention.

5 shows the results of analyzing (SEM) the surface before and after heat treatment of the ruthenium capacitor electrode formed by the method of the present invention.

6 is a view showing the results of the electrical properties before and after the heat treatment of the ruthenium capacitor electrode formed by the method using ammonia plasma according to an embodiment of the present invention.

7 is a view showing the electrical characteristics before and after the heat treatment of the ruthenium capacitor electrode formed by the method using a hydrogen plasma according to an embodiment of the present invention.

The present invention relates to a semiconductor thin film deposition method, and more particularly to a capacitor electrode deposition method.

Although DRAM led the development of semiconductor fixing technology because of high device integration rate, low cost economy, and mass production, Gigabit DRAM has limited cell area per unit device using only existing technologies and materials. Was encountered.

As a countermeasure, a silicon oxide film and a nitride film were used, but the structure was complicated, and new dielectrics and electrodes needed to be developed.

New dielectric materials such as STO, BST, PZT, Ta2O5, etc. are used in DRAM capacitor thin films, and palladium (Pd) has been conventionally used as a capacitor electrode suitable for the dielectric material. Currently, iridium (Ir) and platinum are generally used. (Pt) and ruthenium (Ru) are used. In particular, the use of ruthenium (RU) is increasing trend.

As such, the ruthenium (Ru) thin film used as a capacitor electrode is deposited by a conventional sputter, PVD, CVD, PECVD using plasma, or plasma enhanced atomic layer deposition (PEALD).

However, if the substrate on which the ruthenium thin film is formed is subsequently heat-treated to improve the adhesion between the ruthenium thin film and the oxide thin film deposited by the above method, the oxygen in the ruthenium thin film oxidizes the lower layer to shorten the life of the device. There is a problem.

In addition, due to the cohesion of the materials forming the capacitor electrode after the heat treatment, the capacitor electrode thin films are reconfigured, which causes a problem that the surface of the capacitor electrode thin film is not flat.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above problems, and an object of the present invention is to provide a method for depositing a capacitor electrode having a transition metal capable of improving the reliability of a device by depositing a capacitor electrode thin film having excellent surface roughness after heat treatment. There is this.

According to another aspect of the present invention, there is provided a method of depositing a capacitor electrode including a transition metal, the method comprising: (a) supplying a capacitor electrode source and a transition metal source into a chamber and depositing the same on a substrate provided in the chamber; (b) supplying a gas into a chamber to form the gas atmosphere; (c) densifying the thin film deposited in step (a) by applying a plasma of the same kind as the gas supplied in step (b); (d) purging to remove by-products generated in step (c); And (e) repeating steps (a) to (d).

According to the method described above, the method of depositing a capacitor electrode in which the transition metal is added according to the present invention improves the electrical and physical properties of the capacitor electrode thin film by adding a transition metal during deposition of the capacitor electrode, thereby improving surface morphology. Will be.

In particular, in the subsequent heat treatment of the substrate on which the ruthenium thin film is formed, it is possible to obtain a capacitor electrode thin film having excellent surface roughness by preventing aggregation between materials forming the capacitor electrode.

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

1 is a flowchart illustrating a method of depositing a capacitor electrode in which a transition metal is added according to the present invention, wherein a capacitor electrode source, a source metal source feeding and deposition step (S110), and a plasma applying step (S120) are predetermined. And repeated until a thin film of thickness is obtained.

Based on the components of FIG. 1, the procedure of the capacitor electrode deposition method to which the transition metal is added according to the present invention will be described.

In one embodiment of the present invention, as a method of depositing each source in the capacitor electrode source supply and the transition metal source supply and deposition step (S110), it is possible to use a CVD method of simultaneously supplying and depositing the capacitor electrode source and the transition metal source. have. Furthermore, as another embodiment, an ALD method of supplying and depositing a capacitor electrode source and a transition metal source, respectively, will be described later.

As such, the capacitor electrode source forming the capacitor electrode thin film may use one of iridium, platinum, and ruthenium. As a supply method of such a capacitor electrode source, it can be supplied by various methods currently used. For example, a method of directly supplying a chamber using its own vapor pressure without a carrier gas, or a bubbling method of transporting into a chamber bubbling by argon (Ar) or helium (He), which are inert gases, and a liquid phase. Either method of using a feeder and a vaporizer can be used.

For example, the case of supplying the capacitor electrode source by the bubbling method, by bubbling the capacitor electrode source with Ar or He of 20 ~ 1000sccm heated to 50 ~ 150 ℃ by supplying to the chamber for 0.5 ~ 10sec, An electrode source is deposited on the substrate.

Meanwhile, the transition metal source to be deposited together when the capacitor electrode is deposited, which is a heavy metal such as iron, cobalt, nickel, palladium, osmium, iridium, and platinum, has a high melting point and high breaking point, and an alloy with other metals. It has features that can be made with. It is therefore possible to use one of the transition metal components mentioned above under suitable process conditions.

As the transition metal source supply method, an evaporation method or a sputtering method may be used.

For example, the evaporation method may use a thermal evaporation, an e-beam evaporation, or a combination of the above two methods. In other words, the evaporation method heats a boat using an electron beam (e-beam evaporation) or an electric filament (thermal evaporation) at high vacuum (5 × 10 ⁻⁵ to 1 × 10 ⁻⁷ torr). At this time, the transition metals to be deposited on the boat are heated and the distilled transition metals are condensed on the cold wafer surface.

The sputtering method, which is another embodiment of supplying a transition metal source, is a process of removing particles from a target of a material to be deposited using DC or RF magnetron or plasma, and transferring the particles onto a specific substrate. It is a physical vapor deposition method using the principle that the ionized gas is deposited on a wafer due to a strong collision with a target to be deposited, that is, a region containing a transition metal.

In an embodiment of the present invention, the supply of the transition metal source is not limited to the evaporation or sputtering method as described above. In other words, when the transition metal is liquid, it can be supplied by the same method as the capacitor electrode source described above. For example, nickel, one of the transition metals, is also used in the liquid phase. In this case, the transition metal source may be supplied to the chamber by heating the nickel source to 30 to 250 ° C. and bubbling with Ar or He of 20 to 1000 sccm. .

Meanwhile, in the plasma applying step (S120), plasma is applied into the chamber to densify the thin film deposited through the capacitor electrode source and the transition metal source supply and deposition step (S110).

In the embodiment of the present invention, the plasma applying step is composed of an atmosphere forming step, a plasma applying step, and a purge step. That is, a predetermined gas, for example, ammonia or hydrogen gas, is pre-flowed into the chamber for 1 to 30 sec before the plasma is applied to form an atmosphere. Then, the thin film is densified by applying the same kind of plasma as the gas used to form the atmosphere. It then consists of purging to remove by-products generated during plasma application.

In the embodiment of the present invention, any one of various kinds of plasmas, for example, ammonia plasma, hydrogen plasma, nitrogen plasma, ammonia + nitrogen plasma, ammonia + hydrogen plasma, or the like may be used according to the type of gas component.

The generation of the plasma may be a direct plasma method for generating a plasma directly in the chamber, or a remote plasma method for generating externally and leading into the chamber.

At this time, the frequency of the plasma may use a low frequency 300 ~ 500kHz or RF frequency 13.56MHz can be used. The plasma power is preferably 50 to 2000 W, the application time is about 1 to 60 sec, and the pressure during the process is preferably maintained at 1 mTorr to 10 Torr.

Hereinafter, the capacitor electrode deposition method to which the transition metal component is added according to the present invention will be described in more detail with reference to FIGS. 2 to 7.

Figure 2 shows the procedure of the deposition method using the ALD method of the capacitor electrode deposition method to which the transition metal is added according to the present invention.

As shown in the drawings, a method of depositing a capacitor electrode in which a transition metal is added according to the present invention includes supplying and depositing a capacitor electrode source (S210), a first purge step (S220), supplying and adsorbing a transition metal source (S230), and 2 is a purge (S240), the atmosphere forming step (S250), the plasma applying step (S260), the third purge step (S270).

That is, the capacitor electrode source is fed into the chamber while the substrate is loaded on the stage heater heated to 100 to 600 ° C. In an embodiment of the present invention, a ruthenium source was used as the capacitor electrode source as shown in FIG. 3A. In this case, the ruthenium source is bubbled with Ar or He of 20 to 1000 sccm heated to 50 to 150 ° C. and then supplied to the chamber for 0.5 to 10 sec (S210). Then purge the interior with Ar or He gas (S220). As a result, the ruthenium source remaining in the chamber is removed, as well as reaction by-products including a multi-layer ruthenium source attached to the ruthenium source directly deposited on the substrate are removed.

Next, as shown in FIG. 3a, the nickel source, which is a transition metal source, is heated to 30 to 250 ° C. and bubbled into Ar or He of 20 to 1000 sccm to be supplied to the chamber for 0.5 to 10 sec (S230). Then purge the interior with Ar or He gas (S240). This not only removes the nickel source remaining in the chamber, but also removes reaction by-products including the multilayer nickel source attached to the nickel source deposited directly on the substrate or capacitor electrode source.

Then, the plasma is applied. First, before the plasma is applied, the ammonia gas inside the chamber is pre-flowed for 1 to 30 sec as shown in FIG. 3A to form an atmosphere (S250). Thereafter, a plasma is applied at a power range of 50 to 2000 W and a frequency range of 300 to 500 KHz or 13.56 MHz for 1 to 60 sec. In the embodiment of the present invention, the plasma may be formed as shown in FIG. Hydrogen gas can also be used. As a result, the capacitor electrode source and the transition metal source deposited on the substrate react with each other to densify the thin film.

Then purge using the above-described purge gas (S260). Accordingly, by-products generated during plasma application are removed.

Therefore, as described above, the thin film is densified by the plasma in the state where the capacitor electrode source and the transition metal source are deposited, so that even when the substrate is heat treated, the mutual aggregation between the capacitor electrode materials is caused by the transition metal materials bonded between the capacitor electrode materials. It can be prevented.

That is, Figure 4 shows the results of component analysis (AES) inside the ruthenium thin film to which nickel was formed by the deposition method according to the present invention, and it can be seen that the amount of nickel is somewhat higher. The amount of nickel source is adjustable, so the ratio of ruthenium and nickel can be adjusted.

Therefore, in the method of depositing a capacitor electrode thin film with a transition metal according to the present invention, the cohesive force between capacitor electrode materials is reduced by transition metal materials during heat treatment, thereby improving reliability of the device because of excellent surface roughness. Will be.

That is, Figure 5 shows the results of the analysis (SEM) of the surface before and after the heat treatment (SEM) of the nickel-added ruthenium thin film formed by the deposition method according to the present invention, the annealing is 30 minutes at a temperature of 300 ~ 800 ℃ For 2 hours at, hydrogen, nitrogen, or hydrogen + nitrogen gas using a heat treatment.

5, it can be seen that the surface of the ruthenium thin film to which the transition metal is added before and after the heat treatment is not different.

Meanwhile, FIG. 6 is a graph illustrating electrical characteristics before and after heat treatment of a ruthenium thin film formed by a method using ammonia plasma according to an embodiment of the present invention, and FIG. 7 is a method using a hydrogen plasma according to an embodiment of the present invention. It shows the results of the electrical properties before and after the heat treatment of the ruthenium thin film formed by.

6 and 7, as there is no difference in the surface of the ruthenium thin film to which the transition metal is added, it can be seen that there is no difference in electrical characteristics.

The technical spirit of the present invention has been described above with reference to the accompanying drawings. However, the present invention has been described by way of example only, and is not intended to limit the present invention. In addition, it is apparent that any person having ordinary knowledge in the technical field to which the present invention belongs may make various modifications and imitations without departing from the scope of the technical idea of the present invention.

In the method of depositing a capacitor electrode with a transition metal according to the present invention, the electrical and physical properties can be improved by adding a transition metal, and a capacitor electrode thin film having excellent surface roughness can be deposited, and a capacitor electrode thin film having excellent surface roughness even after heat treatment is obtained. There is an advantage that can be obtained.

In addition, the capacitor electrode thin film deposition method to which the transition metal is added according to the present invention has an advantage of obtaining a capacitor electrode thin film having a desired thickness by repeating a cycle composed of each step of the deposition process.

Claims (9)

In the method of depositing a capacitor electrode, (a) supplying a capacitor electrode source and a transition metal source into the chamber and depositing the same on a substrate provided in the chamber; (b) supplying a gas into a chamber to form the gas atmosphere; (c) densifying the thin film deposited in step (a) by applying a plasma of the same kind as the gas supplied in step (b); (d) purging to remove by-products generated in step (c); And (e) A method of depositing a capacitor electrode with a transition metal, comprising the steps of repeating steps (a) to (d). The method of claim 1, wherein the capacitor electrode source is A method for depositing a capacitor electrode with a transition metal, characterized in that any one of iridium, platinum and ruthenium (Ru). The method of claim 1, wherein the transition metal source is A method for depositing a capacitor electrode with a transition metal, characterized in that any one of iron, cobalt, nickel, palladium, osmium, iridium, or platinum. The method of claim 1, wherein the supply of the capacitor electrode source and the transition metal source is Either by direct supply to the chamber using its own vapor pressure, by bubbling with argon or helium, which is an inert gas, or by supplying it to the chamber by a liquid delivery system and a vaporizer. Capacitor electrode deposition method with a transition metal added, characterized in that using. The method of claim 1 wherein the supply of the transition metal source is A method for depositing a capacitor electrode with a transition metal, characterized in that any one of an evaporation method and a sputtering method is used. The method of claim 1, wherein step (a) And depositing by the CVD method of simultaneously supplying and depositing the capacitor electrode source and the transition metal source. The method of claim 1, wherein step (a) And depositing by supplying the capacitor electrode source and depositing by supplying the transition metal source. The method of claim 7, wherein the ALD method (a1) supplying a capacitor electrode source to the chamber and depositing on the substrate; (a2) purging the inside of the chamber with purge gas to remove residual capacitor electrode sources not deposited on the substrate in step (a1) and simultaneously removing reaction by-products; (a3) heating a transition metal source to supply it to a chamber and depositing it on a substrate; (a4) purging the inside of the chamber with a purge gas to remove the remaining transition metal source not deposited on the substrate in the step (a3) and simultaneously removing half the by-products. One capacitor electrode deposition method. According to claim 1, wherein step (b), A method of depositing a capacitor electrode with a transition metal, wherein any one of ammonia gas, hydrogen gas, nitrogen gas, ammonia and nitrogen mixed gas, and ammonia and hydrogen mixed gas are supplied into the chamber.

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