JPH0414874A - Metal wiring structure of semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To obtain a high-performance, highly reliable semiconductor integrated circuit device by forming titanium boride on titanium, and by forming a conductive film. CONSTITUTION:A p-type or n-type diffusion layer 104 is formed at the bottom part of a contact hole 103 which is opened in layer-to-layer insulating film 102 composed of silicon oxide film and a silicon nitride film on a semiconductor substrate 101. Then, a titanium 105 is formed, and boron ions 106 are implanted in the titanium 105. As a result, titanium reaction for boride occurs under unbalanced condition at low temperatures. This leads to formation of titanium boride 107 with extremely stable chemically and low electric resistance at a high melting point where composition is TiB2 is made on the surface layer of the titanium 105. then, heat treatment is applied to titanium boride for stabilization in non-oxidizing ambient atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a wiring structure and a method for forming a semiconductor integrated circuit device. Maintaining adhesion between titanium boride and lower wiring and insulating films provided on wiring or insulating films, improving heat resistance, and reducing contact resistance.

Electromigration (hereinafter referred to as E, M) resistance, stress migration (hereinafter referred to as S, M,
) A semiconductor integrated circuit composed of a titanium boride for the purpose of improving durability and heat resistance, and a single-layer or multiple-layer conductive film provided on the titanium boride for the purpose of reducing wiring resistance. The present invention relates to a device wiring structure and forming method.

C. Prior Art] As shown in FIG. 4(a), the conventional metal wiring structure and formation method of a semiconductor integrated circuit device is based on a process such as photolithography, dry etching, ion implantation, thermal diffusion, CVD, etc. on a semiconductor substrate 101. Using a known method, for example, a film with a thickness of 0 consisting of two silicon oxide films, two silicon nitride films, etc.
．． A structure is formed in which a p-type or n-type diffusion layer 104 exists only at the bottom of a contact hole 103 opened in an interlayer insulation film 102 with a thickness of 5 to 1.0 μm.

Next, as shown in (b), titanium 105 was deposited using a known method or by C magnetron sputtering under conditions of a power of 2 to 10 KW and a pressure of 5 to 20 mTorr.
It is formed with a thickness of 5 to 0.20 μm. titanium 105
is formed for the purpose of reducing contact resistance, ensuring ohmic contact with the diffusion layer, improving adhesion between upper and lower layers, improving heat resistance, etc.

Subsequently, titanium nitride 108 was deposited at 0.05% by reactive sputtering using titanium as a target and N2 as a reactive gas, or by CVD using a TIC14 reaction source.
Form on titanium 105 to a thickness of 0.05 to 0.20 μm, or sputter only the surface portion of titanium 105 by lamp annealing using N3 or NH3 gas.
Nitriding is performed to the same thickness as that formed by the CVD method to obtain a similar structure.

This titanium nitride 108 prevents diffusion and reaction between the semiconductor substrate and metal wiring, has heat resistance, E resistance, and M resistance.

It is formed for the purpose of improving properties, S, M, and properties, and is generally called a barrier metal.

Furthermore, as shown in (C), at most 5% of aluminum or additional elements such as silicon, copper, palladium, etc.
A conductive film 109 composed of aluminum alloy, copper, gold, etc. containing aluminum alloy, copper, gold, etc. is deposited on the titanium nitride 108, and is deposited by C, magnetron sputtering at a power of 2 to 10 KW and a pressure of 5 to 20 [0.50 at 1 lTOrr. ~1.00
Formed with a thickness of μm.

The conductive film 109 is formed for the purpose of reducing the electrical resistance of the entire wiring structure.

Next, as shown in (d), the known technology of g-line or i
Photolithography method using wire, CBβ3゜SF6
．． CFt C(1<, CI(F3.Dry etching method using A, r, etc. as etching gas and milling gas,
Using the ion milling method, titanium 105° titanium nitride ios is formed into a wiring pattern by removing unnecessary portions of the conductive film 109, and titanium 105° titanium nitride ios is formed on the diffusion layer 104. Titanium nitride 108. Metal wiring of a semiconductor integrated circuit device having a structure composed of the IT film 109 was formed.

[Problem to be solved by the invention]

The conventional metal wiring structure and formation method of a semiconductor integrated circuit device described above has the following drawbacks.

Titanium nitride, which is currently used as a metal material, has a specific resistance value of several tens of μΩ, which is about an order of magnitude higher than the main conductive materials such as aluminum used for wiring of semiconductor integrated circuit devices. Furthermore, when applied to semiconductor integrated circuit devices, heat treatment at temperatures above 500°C significantly increases junction leakage current, which is a requirement for barrier metals with "low reactivity."

It cannot be said that both characteristics of "low electrical resistance" are always satisfied at the same time, and it is difficult to obtain a semiconductor integrated circuit device having high performance and high reliability.

Furthermore, in order to improve heat resistance, it is necessary to increase the thickness of the titanium nitride film, but this makes etching difficult, making it difficult to improve yield in the production process.

[Means to solve the problem]

The metal wiring structure and formation method of a semiconductor integrated circuit device according to the present invention are provided on a diffusion layer and on polycrystalline silicon.

It has a wiring made of titanium formed on a metal silicide, a metal wiring, or an insulating film, a titanium boride formed on the titanium, and a conductive film formed on the titanium boride, and the diffusion A step of forming titanium on a layer, polycrystalline silicon, metal silicide, metal wiring, or an insulating film, and a step of forming titanium boride on the titanium or boriding the surface layer of the titanium. and forming a single layer or multiple layers of conductive film on the titanium boride;
Next, there is a step of removing only unnecessary portions and forming wiring.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention.

As shown in FIG. 1(a), lithography, dry etching, and ion implantation are performed on a semiconductor substrate 101.

Using known methods such as thermal diffusion and CVD, the film is made of silicon oxide film, silicon nitride film, etc. with a thickness of 0.5 cm.
A p-type or n-type diffusion layer 10 is formed at the bottom of a contact hole 103 opened in a ~1.0 μm interlayer insulating film 102.
4 forms a structure in which it exists.

Subsequently, as shown in (b), a film was formed using a known technique or by magnetron sputtering with a power of 1 to 10 KW.
Titanium 105 is formed to a thickness of 0.05 to 0.30 μm under a film forming pressure of 5 to 30[1 l TOrr, and boron ions 106 are added to titanium 105 by ion implantation using B or B F 2 as a source. 30
Implantation is performed under the conditions of -90 KeV, I x 1015 to 5 x1019 pieces/d, and an implantation angle of O to several degrees.

When boron ions are implanted into titanium, a boriding reaction of titanium occurs at low temperatures and in non-equilibrium conditions, and the surface layer of titanium 105 has a composition of TiB2, which has a high melting point, is extremely stable chemically, and has a specific resistance of several μΩ. - A titanium boride 107 having a low electrical resistance is formed.

Subsequently, a heat treatment is performed at about 300° C. to 500° C. in a non-oxidizing atmosphere to stabilize the titanium boride 107. The thickness of titanium boride 107 depends on the implantation energy,
Injected ion amount and implantation angle.

Since it varies depending on the heat treatment conditions, it is necessary to find the optimal conditions for each individual semiconductor integrated circuit device.

Furthermore, as shown in (C), aluminum alloys containing at most 5% of additive elements such as silicon, copper, palladium, etc. that have the effect of preventing and suppressing E, M, S, M, copper, gold, etc. The conductive film 109 having a low electrical resistance is formed using a known technique or by the C. McNetron-Batter method at a film forming power of 2 to 10 KW and a film forming pressure of 5.
050-1.00μm under the condition of ~30mTorr
is formed on titanium boride 107 to a thickness of .

The conductive film is formed primarily to reduce the electrical resistance value of the entire wiring structure. When the conductive film is made of copper, gold, or the like, it can be formed by an electrolytic plating method or an electroless plating method using a mask for wiring formation such as a photoresist.

Subsequently, as shown in (d), photolithography using g-line or i-line, ECβ3. CF,,SF6゜CH
F3. The conductive film 109 is etched using known techniques such as dry etching and ion milling using Ar or the like as an etching gas and a milling gas. Titanium boride 107.
Unnecessary portions of titanium 105 are removed to form a wiring pattern.

Through the above operations, metal wiring of a semiconductor integrated circuit device consisting of three layers of titanium, titanium boride, and a conductive film is formed on the diffusion layer.

In the method for forming metal wiring in a semiconductor device according to the present invention, the lower layer of titanium is not limited to a diffusion layer but also polycrystalline silicon.

It can also be applied to metal silicides, metal wiring, and insulating films.
It is also possible to use a plurality of layers of conductive films to form a four-layer wiring structure. Furthermore, MOS, Bipolar.

Needless to say, it is applicable to any type of semiconductor integrated circuit device such as Bi-0MO3.

Next, other embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a longitudinal sectional view of an embodiment of the present invention. Second
As shown in Figure (a), lithography and dry etching are performed on the semiconductor substrate 101.

Using known techniques such as ion implantation, thermal diffusion, and CVD,
For example, p-type or n-type
A structure in which a type diffusion layer 104 exists is formed.

Subsequently, as shown in (b), a known technique or C.

Deposition power 1 to 10K by McNetron Batter method
Titanium 105 was formed to a thickness of 0.05 to 0.30 μm under the conditions of W, film formation pressure of 5 to 30 mTorr, and low pressure using TiC (!< as the reaction source and Ba5s or BCffl as the boride gas). By boriding using plasma CVD method, for example, the substrate temperature is 200-600℃.
00°C, pressure 20-500rnTorr.

Titanium 105 under conditions such as power 0.2 ~ IKW
Only the surface layer of is borated to form titanium boride 106 with a thickness of 0.05 to 0.20 μm. Since the physical properties such as composition 2 thickness and stress of the titanium boride formed vary depending on plasma boration conditions such as gas ratio, RF power, and substrate temperature, conditions are set that match the semiconductor integrated circuit device to be applied. Among titanium borides, one having the composition TiB2 in particular is chemically extremely stable, has a high melting point, and has a low electrical resistance of several μΩ, so it can be said to be an optimal material for barrier metals.

Subsequently, a heat treatment is performed at about 300° C. to 500° C. in a non-oxidizing atmosphere to stabilize the titanium boride 106.

Furthermore, as shown in (C), E, M, etc. of aluminum, silicon, copper, palladium, etc. are added to aluminum.

A conductive film 109 having low electrical resistance made of a metal such as aluminum alloy, copper, or gold containing at most 5% of an additive element that has the effect of preventing or suppressing S, M, etc. is manufactured using known technology. C. Film-forming power was 2 to 10 KW by Madanestron Batter method.

0.50 to 1 under conditions of film formation pressure of 5 to 30 mTorr
．． 00 μm thick on titanium boride 106. The conductive film is formed with the main purpose of reducing the electrical resistance value of the entire wiring structure. The conductive film is formed primarily to reduce the electrical resistance value of the entire wiring structure. When the conductive film is made of copper, gold, or the like, it can be formed by electrolytic plating or electroless plating.

Next, as shown in (d), photolithography techniques using g-line or i-line, BCffl, CF, are applied.

SF6.0HF3. The conductive film 1o9. Titanium poride 106. Unnecessary portions of titanium 105 are removed to form a wiring pattern. Through the above operations, metal wiring of the semiconductor device is formed on the diffusion layer, which is composed of three layers of titanium, titanium boride, and a conductive film.

〔Effect of the invention〕

As explained above, the method for forming metal wiring in a semiconductor device according to the present invention is performed on a diffusion layer or polycrystalline silicon.

Titanium is placed on the metal silicide, metal wiring, or insulating film for the purpose of maintaining adhesion between the titanium boride and the underlying wiring or insulating film, reducing contact resistance, ensuring ohmic bonding, etc., and titanium on the titanium. titanium boride, which has lower electrical resistance and higher heat resistance than titanium nitride, which is conventionally used as a barrier metal, and the titanium Reduction of wiring resistance provided on boride, overall wiring E, M, resistance, S, M,
Metal interconnects made of conductive films with the aim of improving durability can be easily formed, making it possible to create semiconductor integrated circuit devices with stable characteristics that have better electrical properties and higher long-term reliability than conventional interconnects. There are benefits to be gained.

FIG. 3 shows the electrical characteristics of the wiring according to the present invention and the conventional wiring.

[Brief explanation of drawings]

FIGS. 1(a) to 1(d) are longitudinal sectional views of an embodiment of the present invention;
2(a) to 2(d) are longitudinal cross-sectional views of other embodiments of the present invention, FIG. 3 is electrical characteristic diagrams of wiring of the present invention and conventional wiring, and FIG. 4 (
a) to (d) are vertical cross-sectional views of a conventional method for forming metal wiring in a semiconductor device. 101...Semiconductor substrate, 102...Interlayer insulating film, 103...Contact hole, 10
4...Diffusion layer, 105...Titanium, 106...Boron ion, 107...
・Titanium poride, 1o8・Old・・Titanium nitride, 109・・River・Conductive film. Agent Patent Attorney Susumu Uchihara 1st closing<d) 36θ #0 5θθ Heat treatment temperature compensation (te) Figure 3 Electricity 11 Y Figure π3 Cod Figure 4 α)

Claims (1)

[Claims] 1. In a semiconductor integrated circuit device, titanium formed on a diffusion layer, polycrystalline silicon, metal silicide, metal wiring, or an insulating film, titanium boron formed on the titanium. 1. A metal wiring structure for a semiconductor integrated circuit device, characterized in that the metal wiring structure has a wiring made of a single layer or multiple layers of conductive film formed on the titanium boride. 2. In the semiconductor integrated circuit device, a step of forming titanium on the diffusion layer, polycrystalline silicon, metal silicide, metal wiring, or insulating film, and a step of forming titanium boride on the titanium. A method for forming metal wiring for a semiconductor integrated circuit device, comprising the steps of: forming a single layer or multiple layers of conductive film on the titanium boride; and forming wiring by removing only unnecessary portions.