KR100671612B1 - Apparatus for depositing metal and a method for forming a metal layer using the same - Google Patents

Abstract

The present invention relates to a metal deposition apparatus and a method for forming a metal layer using the same. The present invention relates to a first gas supply pipe connected to a chamber by a chamber in which a wafer chuck is installed so that a wafer can be placed on a bottom surface thereof, and a first pipeline in which a first valve is installed. A plasma generating unit receiving a reaction gas through the gas, a metal raw material storage container connected to the chamber by a second pipe line provided with a second valve, a second gas supply pipe having a third valve and receiving an inert gas, and It comprises an exhaust pump which is connected to the chamber by a third conduit with four valves.

CVD, chamber, radical, ion, adsorption, metal, reduction

Description

Metal deposition equipment and method for forming metal layer using same {Apparatus for depositing metal and a method for forming a metal layer using the same}             

1 is a block diagram of a metal deposition equipment according to the present invention.

2A and 2B are cross-sectional views of devices for explaining the metal layer forming method according to the present invention.

<Explanation of symbols for main parts of the drawings>

1: first duct 2: plasma generator

3: first valve 4: chamber

5: wafer chuck 6: wafer

7: second pipe 8: second valve

9: metal raw material storage container 10: fourth valve

11: third conduit 12: exhaust pump

13: 3rd valve 14: 2nd gas supply line

15: first gas supply pipe 20: semiconductor substrate

21: insulating film 22: metal raw material

22a: metal

The present invention relates to a metal deposition apparatus and a method for forming a metal layer using the same, and in particular, chemical vapor deposition (CVD) equipment configured to supply radicals or ions into a chamber during deposition; It relates to a metal layer forming method using the same.

In general, as semiconductor devices are highly integrated and high speed, copper (Cu) is applied as a metal wiring material of the device. In this case, a diffusion barrier layer is formed under the copper (Cu) layer by using Ta, TaN, TiN, or the like. In comparison with TiN, Ta and TaN having excellent diffusion preventing properties are mainly used. In particular, Ta has an excellent diffusion preventing property, thereby improving the reliability of the copper (Cu) wiring.

Ta and TaN are usually deposited by physical vapor deposition (PVD) methods such as collimated sputtering, long-throw sputtering, ionized physical vapor deposition (I-PVD), and the like. .

However, as the semiconductor devices are highly integrated, it is difficult to deposit such metals by physical vapor deposition (PVD) method anymore, so chemical vapor deposition (CVD) is performed in the manufacturing process of devices having a design rule of 0.1 μm. It is anticipated that deposition of anti-diffusion metal using the method will be required.                         

In order to deposit Ta and TaN by chemical vapor deposition (CVD), a metal raw material, that is, a precursor (precursor) is required, and an organometallic compound including TaCl ₅ or Ta is currently used as a precursor of Ta. However, TaCl ₅ has a high deposition temperature and has a problem of containing chlorine (Cl), and when the organic metal compound is deposited by a metal organic chemical vapor deposition (MOCVD) method, a high resistivity and a large amount of hydrocarbon There is a problem contained.

Accordingly, the present invention provides a method for newly forming a chemical vapor deposition (CVD) device to deposit a diffusion barrier metal by chemical vapor deposition (CVD) method, and to form a diffusion barrier metal layer using the same. .

The metal deposition apparatus according to the present invention is connected to the chamber by a chamber in which a wafer chuck is installed so that a wafer can be placed on a bottom portion thereof, and a first pipe line in which a first valve is installed, and receives a reaction gas through a first gas supply pipe. A metal raw material storage container connected to the chamber by a generation unit, a second pipe line provided with a second valve, a second gas supply pipe provided with a third valve and supplied with an inert gas, and a third pipe line provided with a fourth valve. It comprises an exhaust pump connected to the chamber by.                     

In addition, the method for forming a metal layer according to the present invention provides a first step of supplying a gaseous metal raw material into the chamber to chemically adsorb the metal raw material on the surface of the wafer, and a metal raw material remaining without being adsorbed on the surface of the wafer. A second step of performing a purification process to discharge to the outside, a third step of supplying plasma radicals or ions into the chamber to deposit metal on the wafer by a reduction reaction with a metal material adsorbed on the wafer; In order to discharge the metal raw material that has not reacted with the reaction by-product generated during metal deposition to the outside, the fourth step of carrying out the purification process and the first to fourth steps are repeated until the metal of the desired thickness is deposited. There is a fifth step.

The metal raw material is TaCl ₅ , TiCl ₄ or WF ₆ , the purification process of the second and fourth steps is carried out using an inert gas, the plasma radicals and ions are H ₂ , NH ₃ / H ₂ , NF _It is produced by the gas of any one of ₃ / H ₂ and N ₂ / H ₂ .

Next, the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a chemical vapor deposition (CVD) equipment according to the present invention.

A wafer chuck 5 on which the wafer 6 is mounted is provided on the bottom surface of the chamber 4. The first conduit 1 connected to the plasma generator 2 is connected to an upper portion of the chamber 4, and a first valve 3 is installed in the first conduit 1. The first gas supply pipe 15 through which the reaction gas is supplied is connected to the plasma generation unit 2. A second pipe line 7 connected to the metal raw material storage container 9 and a second gas supply pipe 14 to which an inert gas is supplied are connected to the side wall of the chamber 4, respectively. Two valves 8 are installed, and a third valve 13 is installed in the second gas supply pipe 14. In addition, a third conduit 11 connected to the exhaust pump 12 is connected to the other side wall of the chamber 4, and a fourth valve 10 is installed in the third conduit 11.

The exhaust pump 12 uses a turbomolecular pump having a high exhaust pressure.

Next, a process of depositing a metal on a wafer using the metal deposition apparatus configured as described above will be described with reference to FIGS. 2A and 2B.

First step: supply metal raw materials

The second valve 8 is opened so that a gaseous metal raw material is supplied into the chamber 4 from the metal raw material storage container 9 through the second conduit 7. The supplied gaseous metal raw material is then chemically adsorbed onto the surface of the wafer 6. At this time, the feed amount is controlled so that the metal raw material is adsorbed onto the entire surface of the wafer 6 to allow sufficient reaction.

2A shows a state in which the metal raw material 22 is adsorbed on the semiconductor substrate 20 on which the insulating film 21 is formed.

Second step: purification and exhaust

By closing the second valve 8 and opening the third valve 13, inert gas such as argon (Ar) and helium (He) is introduced into the chamber 4 through the second gas supply pipe 14. At the same time, the fourth valve 10 is opened and the exhaust pump 12 is operated. Then, the metal raw material remaining without being adsorbed to the wafer 6 is discharged to the outside through the third conduit.

Third step: metal deposition

The third and fourth valves 13 and 10 are closed and a reaction gas is supplied to the plasma generation unit 2 through the first gas supply pipe 15 to generate plasma, and the first valve 3 Open so that the radicals or ions contained in the plasma are supplied into the chamber 4 through the first conduit 1. At this time, metal is deposited on the wafer 6 by a reduction reaction between the supplied radicals or ions and the metal raw material adsorbed on the wafer 6, and at the same time, a reaction dispersion is generated. 2B shows a state in which a metal 22 is deposited on the insulating film 21.

At this time, a high-density plasma source such as an IC (Inductively Coupled) plasma, an ECR (Electron Cyclotron Resonance) plasma, a Helicon plasma, or the like is used as the plasma source.

Fourth step: purification and exhaust

When the first valve 3 is closed and the third and fourth valves 13 and 10 are opened to allow the inert gas to be supplied into the chamber 4 through the second gas supply pipe 14, the reaction by-products and residues remain. Metal raw material is discharged to the outside through the third conduit (11).

Step 5: The above steps 1 to 4 are repeated until a thin metal film having a desired thickness is deposited.                     

For example, when a Ta layer is to be formed on the wafer 6, TaCl ₅ is used as a metal raw material, and H ₂ is used as a reaction gas for generating the plasma. Then, Ta is deposited on the wafer 6 by the reduction reaction of TaCl ₅ adsorbed onto the wafer 6 with hydrogen (H) radical or hydrogen (H) ion, and H2 is not reacted at the same time. Reaction byproducts (5HCl) are produced, such as H *, H + and the like.

TaCl ₅ + 5H → Ta + 5HCl ↑

In addition, by using the present invention, a metal nitride film may be formed. In order to form the metal nitride film, NH ₃ / H ₂ , NF ₃ / H _2, or N ₂ / H ₂ is supplied to allow N and H radicals and ions to be supplied to the chamber 4, and a reaction such as the following Chemical Formula 2 is generated by a reduction reaction of N and H radicals and a metal raw material to produce the wafer 6. Allow the Ta nitride film to be deposited on it. At this time, reaction by-products (HCl 5), such as N ₂ , NH ₃ , NF ₃ , N *, N +, H ₂ , H *, H +, which are not reacted, are produced.

TaCl ₅ + xN + 5H → TaNx + 5HCl ↑

The present invention can also be used for the deposition of metals such as titanium (Ti) or tungsten (W), TiCl ₄ is used as a metal raw material for depositing titanium (Ti), WF ₆ for depositing tungsten (W) Is used as a metal raw material.

In the case of using TiCl ₄ as a metal raw material, tungsten (W) is deposited on the wafer by a reaction as shown in Chemical Formula 3 below, whereby reaction by-products (HCl) such as H 2, H *, and H + are produced.

TiCl4 + 4H → Ti + 4HCl ↑

As described above, the present invention allows the metal material to be deposited on the wafer by adsorbing the metal material in a gaseous state onto the surface of the wafer and allowing the adsorbed metal material to react with radicals and ions included in the plasma. And purifying the interior of the chamber after the deposition step so that unnecessary metal ions and reaction by-products are discharged out of the chamber.

Therefore, the present invention is superior to the case of using the conventional physical vapor deposition (PVD) method and can deposit a metal thin film having a very small pin hole (Pin Hole). In addition, it is possible to deposit a metal thin film having excellent physical properties and layer covering at a low temperature (400 ℃ or less) than when using a conventional chemical vapor deposition (CVD) method.

 Therefore, by forming the diffusion barrier using the present invention is excellent in the diffusion prevention effect, it is possible to easily manufacture a semiconductor device having a design rule of 0.1㎛.

Claims (9)

delete delete delete delete Supplying a gaseous metal material into the chamber to chemically adsorb the metal material to the surface of the wafer; A second step of performing a purification process for discharging the remaining metal raw material without being adsorbed on the surface of the wafer; Supplying plasma radicals or ions generated by any one of H ₂ , NH ₃ / H ₂ , NF ₃ / H _2, and N ₂ / H ₂ into the chamber to reduce the metal raw material adsorbed on the wafer A third step of depositing a metal on the wafer by reaction; A fourth step of performing a purification process to discharge the metal raw material not reacted with the reaction by-product generated during the metal deposition to the outside; And a fifth step of repeating the processes of the first to fourth steps until a metal having a desired thickness is deposited. The method of claim 5, The metal raw material is a metal layer forming method, characterized in that any one of TaCl ₅ , TiCl ₄ and WF ₆ . The method of claim 5, The second and fourth purification steps are performed using an inert gas. The method of claim 7, wherein The inert gas is any one of argon (Ar) and helium (He) characterized in that the metal layer forming method. delete

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