KR20080020753A - Contamination protecting method of processing gas injection nozzle - Google Patents

Abstract

A method for preventing contamination of a process gas injection nozzle is provided to prevent particles from being formed in a process gas supply nozzle by continuously flowing purge gas like N2 gas and NF3 gas toward a process gas supply nozzle while the supply of process gas through the process gas supply nozzle stops. A semiconductor substrate having a silicon oxide layer is introduced into a process chamber of etch equipment(S300). Process gas for removing the silicon oxide layer is injected into the process chamber through the process gas supply nozzle(S302). Purge gas is firstly flowed through the process gas supply nozzle(S304). While the purge gas reacts with the silicon oxide layer to form reaction products, purge gas is secondly flowed through the process gas supply nozzle(S306). While the semiconductor substrate is heated, purge gas is thirdly flowed through the process gas supply nozzle(S308). The first, second and third flow processes for flowing the purge gas through the process gas supply nozzle can be performed continuously.

Description

Contamination protection method of processing gas injection nozzle

1 shows particles formed in a process gas supply nozzle.

2 illustrates a semiconductor device manufacturing apparatus to which a method for preventing contamination of a process gas injection nozzle according to the present invention can be applied.

3A to 3D illustrate a process of removing a native oxide film formed on a semiconductor substrate.

4 is a flowchart illustrating a method for preventing contamination of a process gas injection nozzle according to the present invention.

<Description of Symbols for Main Parts of Drawings>

100: process chamber 102: chuck

104a, 104b: process gas injection nozzle

The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for preventing contamination of a process gas supply nozzle which can prevent the process gas injection nozzle from being contaminated by particles generated in the process of manufacturing a semiconductor device. .

In general, semiconductor devices are manufactured by depositing and patterning thin films that perform various functions on the wafer surface to form various circuit geometries. The unit process for manufacturing such a semiconductor device is an impurity ion implantation process for implanting impurity ions of Group 3B (e.g., B) or 5B (e.g., P or As) into the semiconductor substrate, insulating or conductive on the semiconductor substrate. A thin film deposition process for forming a material film of the material layer, an etching process for forming a material film formed through the thin film deposition process in a predetermined pattern, and an interlayer insulating film, etc. deposited on the semiconductor substrate, and then polished collectively to eliminate the step It can be classified into a chemical mechanical polishing (CMP) process and a cleaning process for removing contaminants in the process chamber including a wafer. Accordingly, in order to manufacture a semiconductor device, the above-described various unit processes are selectively and repeatedly performed, and the various unit processes are performed in a process chamber that satisfies respective process conditions.

On the other hand, a natural oxide film is formed on the semiconductor substrate in the process of manufacturing a semiconductor device by performing the above unit process. Therefore, in the present field, in addition to the etching process for forming the material film formed through the thin film deposition process in a predetermined pattern, a separate etching process for removing the so-called natural oxide film formed naturally on the semiconductor substrate is performed.

Referring to a conventional etching process for removing a native oxide film, a semiconductor substrate on which a native oxide film is formed is introduced into a process chamber. Subsequently, after forming the inside of the process chamber in a vacuum atmosphere, hydrogen gas radical (H *) and nitrogen fluoride gas (NF ₃ ) are injected.

Then, the hydrogen gas radical (H *) and the nitrogen fluoride gas react with each other to form NHxFy (H * + NF ₃ → NHxFy). At this time, since the NHxFy has a high reactivity with the silicon oxide film which is a component of the natural oxide film, the NHxFy reaches the upper portion of the semiconductor substrate and reacts with the silicon oxide film which is a component of the natural oxide film to react with the reaction product (NH ₄ ) ₂ SiF ₆ ) (NH x F y + SiO ₂ → (NH ₄ ) ₂ SiF ₆ + H ₂ O).

When the semiconductor substrate on which the reaction product ((NH ₄ ) ₂ SiF ₆ ) is formed is heated to 150 ° C. or higher, the reaction product ((NH ₄ ) ₂ SiF ₆ ) is NH ₃ , HF, and SiF ₄ component. Pyrolysates ((NH ₄ ) ₂ SiF ₆ → NH ₃ + HF + SiF ₄ ). As the NH ₃ , HF, and SiF ₄ components are evaporated, the natural oxide film on the semiconductor substrate is neatly removed.

However, in removing the natural oxide layer on the semiconductor substrate through the above process, there is a problem that the process gas injection nozzle for supplying the process gas into the process chamber due to the NH ₃ , HF, SiF ₄ components. That is, hydrogen gas radicals (H *) and nitrogen fluoride gases (NF ₃ ) are injected into the process chamber to remove the natural oxide layer on the semiconductor substrate. When the gas supply is stopped, the process is operated by back pressure. The NH ₃ , HF and SiF ₄ present in the chamber flow into the process gas injection nozzle. As a result, particles 10 as shown in FIG. 1 are present in the process gas injection nozzle.

As such, when particles are formed in the process gas injection nozzle, the particles block the inlet of the nozzles, thereby preventing the supply of a certain amount of process gas into the process chamber, and injecting the process gas into the process chamber. Particles are mixed in the problem that the smooth etching process cannot proceed.

In addition, these particles are not completely removed through the cleaning process performed during PM (Preventive Maintenance), thus acting as a continuous particle source, and are a major cause of shortening the life of process gas injection nozzles and increasing production costs.

An object of the present invention for solving the conventional problems as described above is to provide a process gas injection nozzle contamination prevention method for preventing particles from being introduced into the process gas injection nozzle.

Another object of the present invention is to provide a process gas injection nozzle contamination prevention method for supplying pure process gas containing no particles into a process chamber.

Another object of the present invention is to provide a process gas injection nozzle contamination prevention method for minimizing an increase in production cost due to replacement of the process gas injection nozzle.

Another object of the present invention is to provide a process gas injection nozzle contamination prevention method which can minimize the process loss time to further improve the productivity and reliability of the semiconductor device.

According to an aspect of the present invention, there is provided a process gas injection nozzle contamination prevention method comprising: injecting a semiconductor substrate on which a silicon oxide film is formed into a process chamber of an etching facility; Injecting hydrogen gas radical (H *) and nitrogen fluoride (NF ₃ ) gases into the process chamber through a process gas supply nozzle; Firstly flowing purge gas through the process gas supply nozzle after completing the hydrogen gas radical and nitrogen fluoride gas injection; Secondly flowing purge gas through the process gas supply nozzle while the hydrogen gas radical and the nitrogen fluoride gas react with each other to form a reaction product; And heating the purge gas through the process gas supply nozzle when the semiconductor substrate is heated.

Preferably, the first flow process, the second flow process and the third flow process of flowing purge gas through the process gas supply nozzle are continuously performed.

Further, preferably, N ₂ and NF ₃ are used as the purge gas in the first flow process, the second flow process, and the third flow process.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention. The present invention is not limited to the embodiments disclosed below, but can be embodied in various other forms without departing from the scope of the present invention, and only the embodiments allow the disclosure of the present invention to be complete and common knowledge It is provided to fully inform the person of the scope of the invention.

FIG. 2 illustrates a ULVAC etching facility as a semiconductor device manufacturing facility to which a method for preventing contamination of a process gas injection nozzle according to the present invention can be applied.

Referring to FIG. 2, a process chamber 100 is shown, which is a processing space in an enclosed atmosphere in which an etching process is performed. In addition, the process chamber 100 has a chuck 102 in which a wafer is loaded. Although not shown in the drawings, upper and lower electrodes to which RF power for plasma generation is applied are formed. In addition, process gas injection nozzles 104a and 104b are formed to inject a process gas for an etching process into the process chamber 100.

Therefore, after loading the semiconductor substrate on the chuck 102 formed in the process chamber 100, the material film deposited on the semiconductor substrate is etched in a desired pattern.

However, a natural oxide film of a silicon oxide film (SiO ₂ ) component is formed on the semiconductor substrate by combining oxygen present in air with silicon constituting the semiconductor substrate. As such, when the silicon oxide film is present on the semiconductor substrate, not only does it inhibit the deposition of the insulating film or the conductive film necessary for manufacturing the semiconductor device, but also adversely affects the etching process, causing problems in the etching profile.

Therefore, in the present field, after removing the natural oxide film formed on the semiconductor substrate by using the ULVAC etching equipment shown in FIG. 2, a subsequent thin film deposition process or etching process is performed.

3A through 3D illustrate an etching process for removing a native oxide film formed on an upper portion of a semiconductor substrate.

Referring to FIG. 3A, a native oxide film 202 is formed on the semiconductor substrate 200 by a combination of silicon atoms and oxygen present in air.

Referring to FIG. 3B, the semiconductor substrate 200 on which the natural oxide layer 202 is formed is introduced into the process chamber 100 of the ULVAC etching facility illustrated in FIG. 2. Subsequently, after forming the inside of the process chamber 100 in a vacuum atmosphere, hydrogen gas radicals H * and nitrogen fluoride gas NF through the process gas supply nozzles 104a and 104b of the ULVAC etching facility shown in FIG. 2. ₃ ) Inject. Then, the hydrogen gas radical (H *) and the nitrogen fluoride gas react with each other to form NHxFy (204).

H * + NF ₃ → NHxFy ......... (1)

The NHxFy 204 has a high reactivity with the silicon oxide film which is a component of the natural oxide film 202. Therefore, when the NHxFy 204 reaches the upper portion of the semiconductor substrate 200, the reaction product reacts with the silicon oxide layer (SiO ₂ ), which is a component of the natural oxide layer 202, as shown in Reaction Formula 2 below. ((NH ₄ ) ₂ SiF ₆ ) 206 is formed.

NHxFy + SiO ₂ → (NH ₄ ) ₂ SiF ₆ + H ₂ O ......... (2)

Referring to FIG. 3C, the semiconductor substrate on which the reaction product ((NH ₄ ) ₂ SiF ₆ ) 206 is formed is heated to 150 ° C. or higher. Then, the reaction product 206 is pyrolyzed as shown in Scheme 3 below.

(NH ₄ ) ₂ SiF ₆ → NH ₃ + HF + SiF ₄ ......... (3)

As the pyrolyzed NH ₃ , HF, and SiF ₄ components 208 are evaporated, as shown in FIG. 3D, the native oxide film 202 on the semiconductor substrate 200 is neatly removed.

Although the natural oxide layer on the semiconductor substrate may be neatly removed by the etching process as described above, the process gas injection in which the NH ₃ , HF, and SiF ₄ components generated as a result of the thermal decomposition supply the process gas into the process chamber 100. There is a problem in that particles are introduced into the nozzles 104a and 104b to form particles. When particles are formed inside the process gas injection nozzle, the purity of the process gas is reduced by the particles, and various problems such as shortening the lifespan of the process gas injection nozzles and increasing the production cost. I'm making it.

Therefore, the present invention is to propose a process gas supply nozzle pollution prevention method that can solve the above conventional problems.

4 shows a process gas supply nozzle contamination prevention method according to the present invention.

Referring to FIG. 4, the process gas supply nozzle contamination prevention method according to the present invention will be described. First, a semiconductor substrate on which a natural oxide film is formed is introduced into a process chamber of an etching facility (S300). Subsequently, hydrogen gas radical (H *) and nitrogen fluoride (NF ₃ ) gas are injected into the process chamber through the process gas supply nozzle of the etching facility (S302).

After completion of the hydrogen gas radical (H *) and nitrogen fluoride (NF ₃ ) gas injection, the first core process of the process gas supply nozzle contamination prevention method according to the present invention is purged through the process gas supply nozzle. (purge) 1 liter each of the gas (N ₂ and NF ₃ ) flows (S304). In this case, the purge gas is preferably flowed at the same time as the hydrogen gas radical (H *) and nitrogen fluoride (NF ₃ ) gas injection is completed.

Meanwhile, the hydrogen gas radical (H *) and the nitrogen fluoride gas react with each other to form NHxFy, and the NHxFy has excellent reactivity with the silicon oxide film constituting the natural oxide film. Therefore, while the NHxFy and the silicon oxide film react with each other to form a reaction product ((NH ₄ ) ₂ SiF ₆ ), as the second core process of the process gas supply nozzle contamination prevention method according to the present invention, the process gas supply nozzle Through the purge gas (N ₂ and NF ₃ ) 1 liter each through (S306).

In addition, as a third core process of the process gas supply nozzle contamination prevention method according to the present invention, when heating the semiconductor substrate, 1 liter of purge gas (N ₂ and NF ₃ ) is respectively provided through the process gas supply nozzle. It flows (S308). When the semiconductor substrate on which the reaction product ((NH ₄ ) ₂ SiF ₆ ) is formed is heated to 150 ° C. or higher, the reaction product ((NH ₄ ) ₂ SiF ₆ ) is thermally decomposed to NH ₃ , HF, SiF _4. Evaporates to the components. In addition, the natural oxide film on the upper portion of the semiconductor substrate is neatly removed in the process of evaporating the NH ₃ , HF, and SiF ₄ components (S310).

The NH ₃ , HF, and SiF ₄ components are mostly discharged out of the process chamber through the exhaust line. However, a part of the particles flows into the process gas supply nozzle to form particles in the process gas supply nozzle. However, conventionally, no method or apparatus has been provided for preventing the introduction of NH ₃ , HF, and SiF ₄ components into the process gas supply nozzle. Accordingly, the NH ₃ , HF, and SiF ₄ components are introduced into the process gas supply nozzle to form particles, thereby reducing the purity of the process gas and contaminating the process gas supply nozzle, thereby shortening the service life.

However, as in the step S308, when N ₂ and NF ₃ flows through the process gas supply nozzle during heating of the semiconductor substrate, NH ₃ , HF, and SiF ₄ components are prevented from flowing into the process gas supply nozzle. You can do it. Therefore, particles are not formed inside the process gas supply nozzle, thereby improving the purity of the process gas injected into the process chamber and controlling the process gas injection amount constantly. In addition, it is possible to prolong the life of the process gas supply nozzle to extend the equipment replacement cycle.

In the above, the pollution prevention method of the process gas supply nozzle according to the embodiment of the present invention has been described with reference to the etching facility shown in FIG. 2, but this is merely an embodiment presented to help understanding of the present invention. In addition, the present invention can be applied to other semiconductor device manufacturing facilities to which a process gas supply nozzle is applied.

As described above, in the present invention, the process gas supply through the process gas supply nozzle is stopped and at the same time the purge gas (N2 gas and NF3 gas) continuously flows to the process gas supply nozzle side, the particles inside the process gas supply nozzle Formation can be prevented. As a result, by improving the cleanliness of the process gas supply nozzle, the process gas supply amount is not only uniform but also the purity of the process gas is improved to maximize the process efficiency. It is possible to reduce the increase in fuel costs.

Claims (17)

In the method for preventing contamination of a process gas injection nozzle provided in a semiconductor device manufacturing facility: Injecting a semiconductor substrate having a silicon oxide film into a process chamber of an etching facility; Injecting a process gas for removing the silicon oxide film into the process chamber through a process gas supply nozzle; After completing the process gas injection, firstly flowing purge gas through the process gas supply nozzle; Secondly flowing purge gas through the process gas supply nozzle while reacting with the process gas and the silicon oxide film to form a reaction product; And a third flow of purge gas through the process gas supply nozzle during heating of the semiconductor substrate. The process gas injection nozzle of claim 1, wherein the first flow process, the second flow process, and the third flow process of flowing purge gas through the process gas supply nozzle are continuously performed. Pollution Prevention Methods. 3. The method of claim 2, wherein in the first flow process, the purge gas is flowed at the same time as the process gas injection is completed. The method of claim 3, wherein the purge gas used in the first flow process, the second flow process, and the third flow process is N ₂ and NF ₃ . 5. The method of claim 4, wherein N ₂ and NF ₃ are flowed by one liter each in the first flow process, the second flow process, and the third flow process. 6. The method of claim 5, wherein the process gas is hydrogen gas radical (H *) and nitrogen fluoride (NF ₃ ) gas. The method of claim 6, wherein the reaction product is (NH ₄ ) ₂ SiF ₆ . The method of claim 7, wherein the semiconductor substrate is heated to 150 ° C. or higher. The method of claim 8, wherein when heating the semiconductor substrate on which the reaction product is formed, the (NH ₄ ) ₂ SiF ₆ is evaporated to NH ₃ , HF, and SiF ₄ components. Way. In the method for preventing contamination of a process gas injection nozzle provided in a semiconductor device manufacturing facility: Injecting a semiconductor substrate having a silicon oxide film into a process chamber of an etching facility; Injecting hydrogen gas radical (H *) and nitrogen fluoride (NF ₃ ) gas into the process chamber through a process gas supply nozzle to form NH x F y; Firstly flowing purge gas through the process gas supply nozzle after completing the hydrogen gas radical and nitrogen fluoride gas injection; Secondly flowing purge gas through the process gas supply nozzle while the NHxFy reacts with a silicon oxide film to form a reaction product; And a third flow of purge gas through the process gas supply nozzle during heating of the semiconductor substrate. The process gas injection nozzle of claim 10, wherein the first flow process, the second flow process, and the third flow process of flowing purge gas through the process gas supply nozzle are continuously performed. Pollution Prevention Methods. 12. The method of claim 11, wherein the purge gas flows at the same time as the hydrogen gas radical and nitrogen fluoride gas injection is completed. The method of claim 12, wherein the purge gas used in the first flow process, the second flow process, and the third flow process is N ₂ and NF ₃ . 15. The method of claim 13, wherein N ₂ and NF ₃ are flowed by one liter each during the first flow process, the second flow process, and the third flow process. The method of claim 14, wherein the reaction product is (NH ₄ ) ₂ SiF ₆ . The method of claim 15, wherein the semiconductor substrate is heated to 150 ° C. or higher. The method of claim 16, wherein when heating the semiconductor substrate on which the reaction product is formed, the (NH ₄ ) ₂ SiF ₆ is evaporated to NH ₃ , HF, and SiF ₄ components. Way.

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