KR100250733B1 - Forming method of multi metal layers in a semiconductor device - Google Patents

Abstract

PURPOSE: A method for forming multi-metal layers of a semiconductor device is provided to prevent generation of compounds due to mutual reaction of metals by forming a protecting metal layer on a lower metal layer. CONSTITUTION: After an insulating film(23) is formed on a silicon substrate(21) where a junction portion(22) is deposited, a first contact hole is formed by patterning the insulating film(23) for the junction portion(22) to be exposed. Then, a barrier metal layer(25) and a first metal layer(26) are sequentially formed on an entire surface and a protecting metal layer(27) is formed on the first metal layer(26). After a first anti-reflective coating(28) is formed on the protecting metal layer(27), a first metal wire is formed by patterning the first anti-reflective coating(28), the protecting metal layer(27), the first metal layer(26) and the barrier metal layer(25) sequentially. A second contact hole is formed by patterning an intermetal dielectrics(29) for a predetermined portion of the first metal wire to be exposed. Then, a second metal wire is formed by sequentially patterning a second anti-reflective coating(33), a second metal layer(32) and a wetting layer(31) formed on the resultant structure.

Description

Method of forming multiple metal layers in semiconductor devices

The present invention relates to a method for forming a multi-metal layer of a semiconductor device, and more particularly, to a method for forming a multi-metal layer of a semiconductor device to reduce the contact resistance between the metal layers.

In general, in the process of manufacturing a semiconductor device, the metal layer is formed in a double or multiple structures, and an intermetallic insulating film is formed between the metal layers for insulation and planarization. In addition, the connection between the metal layers is made through contact holes formed in the interlayer insulating film. As the semiconductor devices are highly integrated, the size of the contact holes is further reduced, which makes it difficult to embed metal in the contact holes. . Therefore, in recent years, a metal wire forming technology using tungsten (W) has been actively studied, and has been applied to the manufacture of devices. In this case, the first metal layer is formed of tungsten, and the second metal layer connected to the first metal layer is formed using aluminum (A1). Then, the method of forming a multi-metal layer of the conventional semiconductor device as described above is illustrated in FIGS. Explained through 1D is as follows.

1A to 1D are cross-sectional views of a device for explaining a method of forming a multiple metal layer of a conventional semiconductor device.

FIG. 1A illustrates a state in which a first contact hole 4 is formed by forming an insulating film 3 on the silicon substrate 1 on which the junction part 2 is formed, and then patterning the insulating film 3 so that the junction part 2 is exposed. It is a cross section.

Referring to FIG. 1B, the barrier metal layer 5 is formed by sequentially depositing titanium (Ti) and titanium nitride (TiN) on the entire structure. Tungsten (W) is deposited on the barrier metal layer 5 to fill the first contact hole 4 to form the first metal layer 6, and the anti-reflection film 7 is formed on the first metal layer 6. . The antireflection film 7, the first metal layer 6 and the barrier metal layer 5 are sequentially patterned to form the first metal wiring 6A.

Referring to FIG. 1C, after forming the interlayer insulating film 8 over the entire structure, the second interlayer insulating film 8 is patterned so that a predetermined portion of the first metal wiring 6A is exposed to form the second contact hole 9. Form. The exposed anti-reflection film 7 of the second contact hole 9 is removed.

Referring to FIG. 1D, after depositing titanium (Ti) on the entire structure to form the wetting layer 10, aluminum (A1) is deposited on the wetting layer 10 to fill the second contact hole 9. The second metal layer 11 is formed. After the anti-reflection film 12 is formed on the second metal layer 11, the anti-reflection film 12, the second metal layer 11, and the wetting layer 10 are sequentially patterned to form a second metal wiring.

However, in the case of using the method as described above, the metal compound 13 is formed between the first metal layer 6 and the second metal layer 11 by the mutual reaction of the tungsten (W) and the aluminum (A1) during the heat treatment performed in a subsequent process. Is generated. The metal compound 13 is made of WA1 ₁₂ , WA1 _5, Ti-W-A1, etc., which have high self-resistance and increase the contact resistance between the first metal layer 6 and the second metal layer 11. Deteriorates electrical characteristics.

Accordingly, an object of the present invention is to provide a method for forming a multi-metal layer of a semiconductor device which can solve the above-mentioned disadvantages by forming a protective metal layer on the lower metal layer by performing a plasma treatment after forming the lower metal layer.

The present invention for achieving the above object is formed by forming an insulating film on the silicon substrate on which the junction is formed, patterning the insulating film so that the junction is exposed to form a first contact hole, and forming a barrier metal layer on the entire structure And performing a heat treatment to form a tungsten film on the barrier metal layer, performing a nitrogen plasma treatment to form a WN _X film on the tungsten film, and then forming a first anti-reflection film on the WN _X film; Sequentially patterning the first anti-reflection film, the WN _X film, the tungsten film, and the barrier metal layer to form a first metal wiring, and forming an intermetallic insulating film over the entire structure, and then exposing a predetermined portion of the first metal wiring. Patterning the interlayer insulating film to form a second contact hole and exposing the first anti-reflection film of the second contact hole Forming a second metal wiring by sequentially forming a wetting layer, an aluminum film, and a second anti-reflection film on the entire structure, and then sequentially patterning the second anti-reflection film, the aluminum film, and the wetting layer. It is characterized by consisting of.

1A to 1D are cross-sectional views of a device for explaining a method of forming a multiple metal layer of a conventional semiconductor device.

2A to 2E are cross-sectional views of a device for explaining a method of forming a multi-metal layer of a semiconductor device according to the present invention.

* Explanation of symbols for main parts of the drawings

1 and 21: silicon substrate 2 and 22: junction

3 and 23: insulating film 4 and 24: first contact hole

5 and 25: barrier metal layer 6 and 26: first metal layer

6A and 26A: first metal wirings 7 and 28; 1st anti-reflection film

8 and 29: interlayer insulating film 9 and 30: second contact hole

10 and 31: wetting layer 11 and 32: second metal layer

12 and 33: second antireflection film 13: metal compound

27: protective metal layer

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

2A to 2E are cross-sectional views of devices for explaining a method of forming a multi-metal layer of a semiconductor device according to the present invention.

FIG. 2A illustrates that the insulating layer 23 is formed on the silicon substrate 21 on which the junction 22 is formed, and then the insulating layer 23 is patterned to expose the junction 22 to form the first contact hole 24. It is a figure of a state.

Referring to FIG. 2B, after the barrier metal layer 25 is formed on the entire structure, heat treatment is performed using a rapid heat treatment apparatus or a heat treatment reactor. Tungsten (W) is deposited on the barrier metal layer 25 to have a thickness of 3000 to 5000 kPa so that the first contact hole 24 is filled to form the first metal layer 26. Plasma treatment may be performed to form a protective metal layer 27 having a thickness of 20 to 500 Å on the first metal layer 26. In this case, when using a nitrogen (N ₂ ) plasma, a protective metal layer 27 such as WN _X is formed on the first metal layer 26. Wherein the plasma treatment is carried out in a plasma chamber having a temperature of 25 to 400 ℃ and a pressure condition of 10 to 200mTorr. In this case, nitrogen (N 2) gas of 50 to 500 SCCM is used as the source gas, and RF power of 50 to 1000 watts (W) is applied to the plasma chamber. In addition, the barrier metal layer 25 is formed by sequentially depositing titanium (Ti) having a thickness of 300 to 500 kPa and titanium nitride (TiN) having a thickness of 500 to 1000 kPa.

2C shows that the first anti-reflection film 28, the protective metal layer 27, the first metal layer 26 and the barrier metal layer 25 are formed after the first anti-reflection film 28 is formed on the protective metal layer 27. It is sectional drawing of the state which patterned sequentially and the 1st metal wiring 26A was formed.

Referring to FIG. 2D, after forming the interlayer insulating film 29 over the entire structure, the second interlayer insulating film 29 is patterned so that a predetermined portion of the first metal wiring 26A is exposed to form the second contact hole 30. ). The exposed anti-reflection film 28 of the second contact hole 30 is removed. At this time, even if the protective metal layer 27 is lost to remain about 10 to 300Å.

2E forms a wetting layer 31 by depositing titanium (Ti) on the entire structure to a thickness of 500 to 1000 mm 3. A second metal layer 32 is formed by depositing aluminum (A1) having a thickness of 6000 to 10,000 μm on the wetting layer 31 so that the second contact hole 30 is filled, and forming a second metal layer 32 on the second metal layer 32. 2 anti-reflection film 33 is formed. Thereafter, the second anti-reflection film 33, the second metal layer 32, and the wetting layer 31 are sequentially patterned to form a second metal wiring. Here, the first and second anti-reflection films 28 and 33 are formed by depositing titanium nitride (TiN) in a thickness of 300 to 500 Å.

In the case of using the method as described above, the first metal layer 26 and the second metal layer 32 are not reacted by the protective metal layer 27 even after the subsequent heat treatment. Therefore, generation of the metal compound by the reaction of the first metal layer 26 and the second metal layer 32 can be prevented to achieve stable contact between the metal layers.

As described above, according to the present invention, the lower metal layer is formed and then plasma treatment is performed to form the protective metal layer on the lower metal layer, thereby preventing the formation of metal compounds by the reaction between the metals. Therefore, the contact state between the lower metal layer and the upper metal layer interface is good, and thus the contact resistance between the metal layers can be reduced, thereby improving the electrical characteristics of the device.

Claims (6)

In the method of forming a multiple metal layer of a semiconductor device, Forming an insulating film on the silicon substrate on which the junction is formed, and then patterning the insulating layer to expose the junction to form a first contact hole; Forming a barrier metal layer on the entire structure and then performing heat treatment to form a tungsten film on the barrier metal layer; Performing a nitrogen plasma treatment to form a WN _X film on the tungsten film and then forming a first anti-reflection film on the WN _X film; Sequentially patterning the first anti-reflection film, the WN _X film, the tungsten film, and the barrier metal layer to form a first metal wiring; After the interlayer insulating film is formed on the entire structure, the interlayer insulating film is patterned to expose a predetermined portion of the first metal wiring to form a second contact hole, and the exposed first anti-reflection film of the second contact hole is removed. To do that, Forming a second metal wiring by sequentially forming a wetting layer, an aluminum film, and a second antireflection film on the entire structure, and then sequentially patterning the second antireflection film, the aluminum film, and the wetting layer. Method for forming multiple metal layers in semiconductor devices. The method of claim 1, wherein the tungsten film is formed to a thickness of 3000 to 5000 kPa and the aluminum film is formed to a thickness of 6000 to 10000 kPa. The method of claim 1, wherein the plasma treatment is performed in a plasma chamber to which a temperature of 25 to 400 ℃, a pressure of 10 to 200 mTorr and a high frequency power of 50 to 1000 watts are applied. Way. The method of forming a multi-metal layer of a semiconductor device according to claim 1, wherein the nitrogen amount during said nitrogen plasma treatment is 50 to 500 SCCM. The method of claim 1, wherein the WN _X film is formed to a thickness of 20 to 500 kPa. The method of claim 1, wherein the WN _X film having a thickness of about 10 to about 300 microseconds is left in the process of removing the second anti-reflection film after forming the second contact hole.