KR100415095B1 - Method for manufacturing semiconductor device - Google Patents

Abstract

PURPOSE: A method for manufacturing a semiconductor device is provided to be capable of improving the reliability of a metal interconnection. CONSTITUTION: A barrier metal film(3) is formed on a semiconductor substrate(1) with an insulating layer(2). The first alloy(4) consisting of Al, Si of 1% and Cu of 0.5% is formed on the barrier metal film. The first TiN layer(5) is formed. The second alloy(6) without adding Si in the first alloy is formed on the first TiN layer. At this time, the first Ti-Al compound is formed at interface between the first TiN layer and the second alloy. The second TiN layer(7) and the third alloy(8) with the same material to the first alloy are sequentially formed on the second alloy. The second Ti-Al compound is formed between the second TiN layer and the third alloy. The third TiN layer(9) is then formed.

Description

Manufacturing Method of Semiconductor Device

The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for manufacturing a semiconductor device capable of improving the reliability of metal wiring.

In general, aluminum is the most widely used metal in current wiring processes because of its good properties as a metal wiring material. That is, aluminum can not only be deposited very easily by sputtering, but also has excellent electrical conductivity, high compatibility with silicon substrates, ease of processing, and good adhesion with underlying layers.

Although the formation of the metal wiring using aluminum is not shown, an insulating film is formed on the silicon substrate, an aluminum film is deposited on the silicon substrate, and the aluminum film is patterned by photolithography and etching to form a metal wiring layer.

However, the following problem occurs when forming the metal wiring using the aluminum film described above.

First, when the silicon substrate is annealed at a high temperature, aluminum spiking occurs in which silicon diffuses into the aluminum film due to the high solubility and diffusion coefficient of silicon in aluminum. In addition, the diffused silicon atoms form a recrystallized layer upon cooling to form an ohmic contact. If such a recrystallized layer is locally severely formed, the PN junction is broken and the device degrades. On the other hand, the aluminum spiking occurs mostly at the edge of the contact hole or the bonding site, and depends on the grain size of the aluminum, the crystal direction of the substrate and the amount of aluminum connected to the contact site.

Second, since the coefficient of thermal expansion of the silicon substrate is 3.3 ppm / 占 폚 and the coefficient of thermal expansion of aluminum is 23.6 ppm / 占 폚, the hillock phenomenon occurs due to the large difference in the coefficient of thermal expansion between the silicon substrate and the deposited aluminum film. . Such a hillock is generated in an alloy process of about 400 to 450 ° C., and the protruding height is 2 μm or more, and later, when the mask pattern is formed using the photoresist film, pinholes are formed in the photoresist film, thereby forming a short. Cause

Third, electromigration occurs in which atoms move in the conductor when current flows through the aluminum wiring. By the way, the flow of electrons or holes in a material exerts a force on the atoms at rest in the conductor by the exchange of momentum, so that if the atom is in the proper position, the force is large enough for the atom to move. . In the case of aluminum, a suitable position is a vacant lattice position flowing down from the flow of electrons or holes. This position can be found in the lattice or on the surface of the grain. As a result of the electron transfer, the lower the potential of the electrode is voided, the local current density is increased, the disconnection occurs.

Therefore, in order to solve the above problem, an aluminum alloy film having a composition of Al + 1% Si + 0.5% Cu is used instead of the aluminum film. That is, Si is added to overcome the spiking problem and hillock phenomenon, and Cu is added to reduce the electron transfer.

However, due to the rapid improvement in the degree of integration of the semiconductor device, the unit current density flowing through the metal wiring increases, and the reliability of the aluminum wiring on the surface has emerged as a big problem. That is, the metal wiring using the aluminum alloy film includes existing problems such as reliability of contact with a shallow joint, short circuit between wires due to hillock, and wire breakage due to electron movement or stress movement.

In addition, in order to solve the problem of contact reliability, another conventional method inserts a barrier metal film such as TiN between the silicon substrate and the aluminum film wiring, but the grain size of the aluminum is reduced when the TiN film is covered by the aluminum film. There has been a problem of reducing the resistance to high electron transfer.

Accordingly, the present invention has been made to solve the above-mentioned problems, and includes a barrier metal film made of a Ti film and a TiN film, an Al + 1% Si + 0.5% Cu alloy film, a TiN film, and an Al + 0.5% Cu alloy film. It is an object of the present invention to provide a method for manufacturing a semiconductor device that can improve the reliability of the metal wiring.

1 is a cross-sectional view for explaining a method for manufacturing a metal wiring of a semiconductor device according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

1 silicon substrate 2 insulating film

3: barrier metal film 4,8: alloy film of Al + 1% Si + 0.5% Cu

5,7,9 TiN film 6: Al + 0.5% Cu

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor device, the method including: forming a barrier metal film on a semiconductor substrate on which an insulating film is formed; Forming a first alloy film containing Al and adding Si and Cu on the barrier metal film; Forming a first TiN film on the first alloy film; Forming a second alloy film without Si added in the first alloy film on the first TiN film and simultaneously forming a first Ti-Al compound at an interface between the first TiN film and the second alloy film; Forming a second TiN film on the second alloy film; Forming a third alloy film containing Al and adding Si and Cu on the second TiN film and simultaneously forming a second Ti-Al compound at an interface between the second iN film and the third alloy film; Forming a third TiN film on the third alloy film; and etching the resultant to form a metal wiring layer.

At this time, the first alloy film is Al + 1% Si + 0.5% Cu alloy film, the second alloy film is Al + 0.5% Cu alloy film, the third alloy film is Al + 1% Si + 0.5% Cu alloy film It is characterized by that.

According to the present invention having the above structure, the Al + 1% Si + 0.5% Cu alloy film is formed on the upper and lower Al + 0.5% Cu alloy film, respectively, so that the surface of the Al + 0.5% Cu alloy film is easily oxidized. Can be prevented. In addition, the top layer of the metal wiring layer may be formed of a TiN film to prevent the occurrence of hillock.

EXAMPLE

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

1 is a cross-sectional view illustrating a metal wiring structure of a semiconductor device according to an embodiment of the present invention.

As shown in FIG. 1, the insulating film 2 is formed on the silicon substrate 1. At this time, although not shown, the silicon substrate 1 includes a field oxide film, a gate, and a source / drain region, and the insulating film 2 has a predetermined contact hole.

First, a barrier metal film 3 composed of a multilayer film of a first Ti film having a thickness of about 200 to 400 GPa, a first TiN film of about 500 to 1,000 GPa, and a second Ti film of about 200 to 400 GPa on the insulating film 2. Is formed by sputtering. At this time, the first and second Ti films are respectively formed in an Ar gas atmosphere at a power of about 0.2 to 0.5 kW and a pressure of ¹ × 10 ⁻² Torr or less, and the first TiN film is formed at a temperature of about 300 to 400 ° C. Is deposited in a mixed gas having a ratio of Ar: N ₂ = 1: 1 at a power of about 0.2 to 0.5 kW and a pressure of 1 × 10 ⁻² Torr or less while heating.

Subsequently, the first alloy film 4 of Al + 1% Si + 0.5% Cu on the barrier metal film 3 with a thickness of about 1,000 to 1,500 kW was applied at a low temperature of about 100 to 200 kW and a power of about 5 to 10 kW. Form while maintaining a pressure of 1x 10 ^-2 Torr or less. At this time, a Ti-Al compound is formed at the interface between the barrier metal film 3 and the first alloy film 4, and since the metal wiring is hardly deformed mechanically due to the compound, it has high resistance to stress transfer. do.

Then, a second TiN film 5 is formed on the first alloy film 4 at a thickness of about 200 to 400 kPa, and a second alloy of Al + 0.5% Cu at a thickness of about 3,000 to 5,000 kPa thereon. The film 6 is formed at a temperature of 350 to 500 ° C. while maintaining a power of about 5 to 10 kW and a pressure of ¹ × 10 ⁻² Torr or less. At this time, a Ti-Al compound is formed at the interface between the second TiN film 5 and the second alloy film 6, and in particular, the second alloy film 6 not only has high resistance to electron transfer, but also Si The resistance is lowered because no atoms are added.

Thereafter, a third TiN film 7 was formed on the second alloy film 6 to a thickness of about 200 to 400 mW, and on the top thereof, an Al + 1% Si + 0.5% Cu of about 1,000 to 1,500 mW thick. The third alloy film 8 and the fourth TiN film 9 having a thickness of about 200 to 400 GPa are sequentially formed. Here, like the first alloy film 4, the third alloy film 8 is formed at a low temperature of about 100 to 200 ° C. while maintaining a power of about 5 to 10 kW and a pressure of ¹ × 10 ⁻² Torr or less.

Subsequently, although not shown, metal layers on the insulating film 2 are patterned by photolithography and etching to form a metal wiring layer.

According to the above embodiment, the Al + 1% Si + 0.5% Cu alloy films are formed on the upper and lower Al + 0.5% Cu alloy films, respectively, to prevent the surface of the Al + 0.5% Cu alloy film from easily oxidizing. Can be. In addition, by forming the uppermost layer of the metal wiring layer with a TiN film to prevent the occurrence of hillock, it is possible to form a reliable contact to the shallow contact portion while having high resistance to electron movement and stress movement. Therefore, the wiring reliability of the element can be improved.

In addition, this invention is not limited to the said Example, It can variously deform and implement within the range which does not deviate from the technical summary of this invention.

As described above, according to the present invention, it is possible to realize a method for manufacturing a semiconductor element which can improve the reliability of metal wiring.

Claims (14)

Forming a barrier metal film on the semiconductor substrate on which the insulating film is formed; Forming a first alloy film containing Al and adding Si and Cu on the barrier metal film; Forming a first TiN film on the first alloy film; Forming a second alloy film on which the Si is not added in the first alloy film on the first TiN film and simultaneously forming a first Ti-Al compound at an interface between the first TiN film and the second alloy film; Forming a second TiN film on the second alloy film; Forming a third alloy film containing Al and adding Si and Cu on the second TiN film and simultaneously forming a second Ti-Al compound at an interface between the second iN film and the third alloy film; Forming a third TiN film on the third alloy film; and And etching the resultant to form a metallization layer. The method of claim 1, wherein the first alloy film is an Al + 1% Si + 0.5% Cu alloy film. The method of claim 1, wherein the second alloy film is an Al + 0.5% Cu alloy film. The method of claim 1, wherein the third alloy film is an Al + 1% Si + 0.5% Cu alloy film. The method of claim 1, wherein the first alloy film and the third alloy film are formed to a thickness of 1,000 to 1,500 kPa. The method of claim 5, wherein the first alloy layer and the third alloy layer are formed at a low temperature of 100 to 200 ° C. under a power of 5 to 10 kW and a pressure of 1 × 10 ⁻² Torr or less. . The method of claim 1, wherein the second alloy film is formed to a thickness of 3,000 to 5,000 kPa. The method of claim 7, wherein the second alloy film is formed at a temperature of 350 to 500 ° C. under a power of about 5 to 10 kW and a pressure of 1 × 10 ⁻² Torr or less. The method of claim 1, wherein the barrier metal film has a stacked structure of Ti / TiN / Ti. The method of manufacturing a semiconductor device according to claim 9, wherein the Ti films are formed to have a thickness of 200 to 400 kPa, respectively. The method of claim 10, wherein the Ti film is formed in an Ar gas atmosphere at a power of 0.2 to 0.5 kW and a pressure of 1 × 10 ⁻² Torr or less. 10. The method of claim 9, wherein the TiN film is formed to a thickness of 500 to 1,000 GPa. The TiN film of claim 12, wherein the TiN film has a ratio of Ar: N ₂ = 1: 1 at a power of 0.2 to 0.5 kW and a pressure of 1 x 10 ^-2 Torr or less while heating the substrate at a temperature of 300 to 400 ° C. It is formed in mixed gas atmosphere, The manufacturing method of the semiconductor element characterized by the above-mentioned. The method of manufacturing a semiconductor device according to claim 1, wherein the first to third TiN films are formed to have a thickness of 200 to 400 GPa.