KR20040035280A - Method for in-situ cleaning of deposition chamber - Google Patents

Abstract

PURPOSE: An in-situ cleaning method of a depositing chamber is provided to be capable of carrying out an in-situ cleaning process without the time delay for falling and plasma power. CONSTITUTION: ClF3 gas is flowed into a ruthenium depositing chamber. At this time, the ruthenium depositing chamber is heated to a predetermined temperature. A cleaning process is completed by removing ruthenium remaining in the depositing chamber using the flowed ClF3. Preferably, the depositing chamber includes an Al heater, so that the ruthenium removing process is carried out at the temperature of 200-400 °C. Preferably, the depositing chamber is capable of including an AlN heater, so that the ruthenium removing process is carried out at the temperature of 200-600 °C.

Description

In-situ cleaning of deposition chamber

The present invention relates to an in-situ cleaning method for semiconductor device manufacturing equipment, and more particularly, to a method for in-situ cleaning a chamber for depositing a film in semiconductor device manufacturing equipment.

The process of depositing a ruthenium (Ru) film in the manufacturing process of a semiconductor device is mainly performed by PVD (Physical Vapor Deposition) or CVD (Chemical Vapor Deposition) method, and recently, many processes are performed by MOCVD (Metal Organic CVD) method. Is done. 1 shows a schematic configuration of a MOCVD chamber for depositing a ruthenium film. Referring to FIG. 1, a chamber providing a reaction space by isolating a semiconductor substrate from an external space mainly includes a chamber body 100 and a quartz bell jar 110. The RF electrode 140 for transmitting plasma power to the reaction gas for forming the ruthenium film is installed in a shape surrounding the quartz bell jar 110. In addition, the Belza heater 150 is installed outside the RF electrode 140 to heat the reaction space. Meanwhile, the reaction gas is supplied into the chamber through the gas injector 120, and the semiconductor substrate on which the ruthenium film is deposited is placed on the susceptor 130. When the ruthenium film is deposited in the chamber as shown in FIG. 1, a thick film is deposited on the inner surface of the chamber and the components within the chamber in addition to the semiconductor substrate due to the characteristics of the metal film forming process. The more the ruthenium film deposition process is performed, the thicker the film deposited on the inner surface of the chamber and the components within the chamber, which causes stress peeling, which eventually acts as a source of contamination. Therefore, it is important to perform in-situ cleaning periodically after the ruthenium film deposition process. On the other hand, in the case of etching or patterning the ruthenium film deposited by the PVD method or the CVD method, a method using Cl ₂ plasma is currently applied. Therefore, Cl ₂ plasma can be applied to periodically clean the chamber after the ruthenium film deposition process, which is shown in Chemical Formula 1.

2Ru (s) + 3Cl ₂ → 2RuCl ₃ (s), except 330 ℃ or higher

However, since the etching efficiency is low at a low temperature of 330 ° C. or lower by the Cl ₂ plasma itself, the etching efficiency is enhanced by adding O ₂ gas to activate the gas phase reaction as shown in Formula 2 below.

Ru (s) + O ₂ → RuO ₃ (g) or RuO ₄ (g)

2A to 2C are views illustrating a result of cleaning a substrate on which a ruthenium film / silicon thermal oxide film is formed by a plasma of Cl ₂ gas and O ₂ gas in the apparatus shown in FIG. 1. FIG. 2A is a photograph showing the state of the substrate after cleaning, FIG. 2B is a photograph showing the surface shape of the center portion of the substrate of FIG. 2A, and FIG. 2C is a photograph showing the surface shape of the peripheral portion of the substrate of FIG. 2A. 2B and 2C, the center portion of the substrate has a shape almost similar to that of the surface immediately after the ruthenium film is deposited and shows no significant change, but the periphery of the substrate is etched so that the silicon thermal oxide film is almost exposed. Can be. It can also be seen that by-products remain on the substrate surface after cleaning. As a result of the cleaning, the ratio of the supply amount of Cl ₂ / O ₂ per unit time is 50 to 70%, when the supply amount of Cl ₂ gas per unit time of 300 sccm or more, the lower the pressure and the larger the plasma power, the more the temperature of the substrate The lower the etch rate, the higher the etch rate. The optimized cleaning process conditions were 300 sccm per unit time of Cl ₂ and O ₂ , 0.3 Torr pressure and 100 ℃.

However, according to the conventional ruthenium deposition chamber in-situ cleaning method, since the cleaning is performed by etching the ruthenium film with Cl ₂ and O ₂ activated by the application of plasma power, the uniformity of the cleaning process is largely dependent on the plasma uniformity. After the process, physical damage to components in the chamber is likely to occur. In addition, the use of a high voltage according to the application of the plasma power is required, there is a problem that the generation of contaminating particles is more concerned, and the back of the heater and the substrate pinhole portion is difficult to clean due to the straightness of the plasma. In addition, when the ruthenium film is deposited in a device other than the plasma deposition equipment, there is a problem that conventional methods cannot be applied to the in-situ cleaning of the equipment.

In addition, since the application of the conventional in-situ cleaning method at the deposition temperature causes redeposition, the present method does not apply such in-situ cleaning method at the deposition temperature. Is applying. Therefore, since the process time is inevitably delayed, it is difficult to say that this is substantially in situ cleaning. In addition, since the equipment employing the molding heater takes a long time to increase / decrease the temperature, such a problem is a greater problem in the equipment employing the molding heater.

In addition, when using the conventional in-situ cleaning method using plasma of Cl ₂ gas and O ₂ gas, since aluminum (Al) is easily etched by Cl ₂ plasma, it is possible to use inexpensive Al material as a component in the chamber. Could not. As a solution to this problem, the surface of these components should be protected by anodizing, or by covering with a material such as graphite. However, the use of such a method not only increases the manufacturing cost of the equipment but also reduces the adhesion between the component and the ruthenium film, which causes a short chamber cleaning cycle.

Accordingly, the technical problem of the present invention is to provide a method for in-situ cleaning the deposition chamber without the application of plasma power or a time delay for falling at the deposition temperature.

Another technical problem of the present invention is to provide an in-situ cleaning method of a deposition chamber that can eliminate process delays and minimize damage to equipment components even when the ruthenium deposition chamber employs a molding heater.

It is still another object of the present invention to provide an in-situ cleaning method of a deposition chamber, which exhibits excellent etching process uniformity and high etching rate, thereby enabling rapid process progression.

Another technical problem of the present invention is to provide an in-situ cleaning method of a deposition chamber, which reduces the probability of generation of contaminated particles and enables cleaning of components in the chamber, which is difficult to clean when using plasma.

Another technical problem of the present invention is to provide an in-situ cleaning method of a deposition chamber, which enables the use of low-cost Al or high-temperature AlN material as a component in the chamber.

1 is a sectional view showing a schematic configuration of a MOCVD chamber for depositing a ruthenium film;

2A and 2B show the results of cleaning a ruthenium film / silicon oxide film by plasma of Cl ₂ gas and O ₂ gas in the equipment shown in FIG. 1; And

3A to 3F are views illustrating a process of cleaning a ruthenium film / silicon oxide film by applying the method of the embodiment of the present invention to the equipment shown in FIG. 1.

In-situ cleaning method of the deposition chamber of the present invention for solving the above technical problems: supplying ClF ₃ gas in the ruthenium deposition chamber heated to a predetermined temperature, maintaining the deposition chamber at a constant pressure ClF ₃ supplied while being removed, characterized in that it comprises the step of cleaning by removing the ruthenium remaining in the interior of the deposition chamber.

In the present invention, when the deposition chamber employs an Al heater, the heating temperature inside the chamber in the ruthenium removal step is preferably in the range of 200 ~ 400 ℃.

In the present invention, when the deposition chamber employs an AlN heater, the heating temperature inside the chamber in the ruthenium removal step is preferably in the range of 200 ~ 600 ℃.

In addition, when supplying the ClF ₃ gas, inert gas is supplied together to minimize damage of components in the chamber, and the ratio of the hourly supply of ClF ₃ gas to the hourly supply of the inert gas is preferably 0.4 to 2. Do.

In addition, the pressure in the chamber is preferably maintained at 1 to 30 Torr.

In addition, the method of the present invention may be applied to the case where the deposition chamber includes a molding heater, and may also be applied when at least a portion of the molding heater and the chamber is made of Al or AlN.

The method also includes depositing a predetermined thickness of ruthenium on a wafer in a ruthenium deposition chamber; Separating the deposited wafer out of the chamber; And supplying ClF3 gas into the chamber while maintaining the chamber at a predetermined temperature and pressure to remove and clean ruthenium remaining in the chamber.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention.

ClF ₃ gas and Ar gas were supplied at 300 sccm and 200 sccm, respectively, while maintaining the temperature in the deposition chamber where the ruthenium film deposition process was completed at 260 ° C. similar to the deposition process temperature and maintaining the pressure inside the chamber at 2.5 Torr. In situ washing was performed. During the gas supply and etching step, the gas supply line and the vacuum line supplying the gas to the chamber were heated to a temperature in the range of 100 to 200 ° C. to prevent the generation of contaminating particles.

In order to evaluate the superiority of the method of the present invention, the substrate on which the ruthenium film (500 ms) / silicon thermal oxide film (1000 ms) was formed was cleaned by the method of the above embodiment, and the substrate was subjected to passage of time exposed to ClF ₃ gas. The surface shape of the film was photographed and shown in FIGS. 3A to 3F. 3A shows the surface shape of the ruthenium film immediately after deposition, and FIGS. 3B and 3C show the surface shape of the ruthenium film when the substrate is exposed to ClF ₃ gas for 15 seconds and 30 seconds, respectively, during the application of the method of the present invention. Indicated. 3B and 3C, as the exposure time increases, the surface of the rough ruthenium film becomes smooth as the etching reaction proceeds from the peak region and the boundary region of the grain of the unstable ruthenium film due to the relatively high energy. Able to know. As the process proceeds, it can be observed that as shown in FIG. 3D, the ruthenium film loses its properties while exhibiting a cluster shape. As the exposure of the substrate to the ClF ₃ gas accelerates, the size of the cluster decreases to show island shaped particles, as shown in FIG. 3E. This phenomenon is similar to the observation of the ruthenium film island-type deposition mechanism in the reverse direction.

Furthermore, as a result of exposing the substrate to ClF ₃ gas for 60 seconds, as shown in FIG. 3F, the 500-nm-thick ruthenium film was completely removed without leaving reaction by-products, and the 1000-nm-thick silicon thermal oxide film was also etched about 130 Å and overetched. It can be seen that over-etch) has occurred. It was also confirmed that these results appeared uniformly over the entire surface of the substrate.

As a result of many optimization experiments with the method of the present invention, when the ratio of the hourly supply of ClF ₃ gas to the hourly supply of Ar gas is 0.5 or more, when the hourly supply of ClF ₃ gas is 300 sccm or more, and the pressure is The higher the etching rate, the higher the etch rate. The optimum cleaning conditions were 300 sccm and 200 sccm per unit time of ClF ₃ and Ar, respectively, and the pressure was 2.5 Torr.

According to the method of the present invention, the deposition process at a high etching rate (50nm / min) compared to the conventional method using a Cl ₂ / O ₂ plasma by using ClF ₃ gas as an in-situ cleaning gas without applying plasma power All components in the chamber can be cleaned at temperature, minimizing equipment damage and delays in processing time. Therefore, the throughput of the metal film forming process can be improved.

In addition, when the ruthenium film is deposited in a device other than the plasma deposition equipment, the method of the present invention can be applied to in situ cleaning of the equipment, and even if the ruthenium film is deposited on the plasma deposition equipment, RF power is applied because the plasma power is not used. Noise problems, ground problems, etc. can be fundamentally eliminated.

In addition, since the ruthenium film deposited on the heater can be easily removed, the overall manufacturing cost of the semiconductor device can be lowered by increasing the wet cleaning cycle for the maintenance of the equipment.

Claims (7)

Supplying ClF ₃ gas into the ruthenium deposition chamber heated to a predetermined temperature; and removing the cleaned ruthenium remaining in the deposition chamber by the supplied ClF ₃ in situ of the deposition chamber. Cleaning method. The in-situ cleaning method of a deposition chamber according to claim 1, wherein the deposition chamber employs an Al heater, and the heating temperature inside the chamber in the ruthenium removing step is 200 to 400 ° C. The in-situ cleaning method of a deposition chamber according to claim 1, wherein the deposition chamber employs an AlN heater and the heating temperature inside the chamber in the ruthenium removal step is 200 to 600 ° C. The in-situ cleaning of the deposition chamber according to claim 1, wherein the ClF ₃ gas and the inert gas are supplied together, and the ratio of the hourly supply amount of ClF ₃ gas to the hourly supply amount of the inert gas is 0.4 to 2. Way. The in-situ cleaning method of a deposition chamber according to claim 1, wherein the pressure in the chamber is maintained at 1 to 30 Torr. The method of claim 1, wherein the deposition chamber includes a molding heater, and the molding heater and at least a portion of the chamber are made of Al or AlN. Depositing ruthenium of a predetermined thickness on the wafer in the ruthenium deposition chamber; Separating the deposited wafer out of the chamber; And And injecting ClF3 gas into the chamber while removing the ruthenium remaining in the chamber while maintaining the chamber at a predetermined temperature and pressure.