JP2751223B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wiring structure of a semiconductor device and a method of manufacturing the same.

[Summary of the Invention]

An object of the present invention is to provide a semiconductor device which is highly reliable and can be stably produced by including oxygen or silicon on the surface of a barrier metal in a wiring structure of the semiconductor device, and a method of manufacturing the same.

[Conventional technology]

As disclosed in Japanese Patent Application Laid-Open No. 61-142739, a conventional wiring device for a semiconductor device forms a refractory metal layer on an insulating film and a contact opening surface and then heat-treats the metal surface to form a metal nitride and a metal. The semiconductor interface is silicided, and then a wiring metal is formed on the metal nitride.

[Problems to be solved by the invention]

In recent years, as semiconductor devices have been miniaturized, contact openings on semiconductor substrates have also been miniaturized. Along with that, various issues have become apparent. One is the problem of increasing the contact resistance, and the other is
This is a disconnection of the Al wiring. The former occurs because silicon in the Al wiring is deposited on the contact portion, and the latter occurs because Al does not enter a contact having a small diameter and a large depth. As a solution to these problems, it is conceivable that silicon is not put into the Al wiring for the former, but if it is left as it is, Al diffuses into the substrate and causes junction leakage, so the gap between the Al wiring and the substrate diffusion layer There is a method of inserting a barrier metal. For the latter, there is a bias sputtering method in which a bias voltage is applied to a substrate when Al is formed by a sputtering method.

In the above-mentioned conventional technology, when this is used for a semiconductor device having a multilayer wiring, there is a problem that Al diffuses to a substrate due to heat in a later process such as formation of a wiring metal in an upper layer, and the barrier property is not sufficient. . In addition, when the wiring metal is formed by the above-described bias sputtering method, the conventional technique has a problem that the wettability between the barrier metal and the Al wiring is not sufficient, and the Al 201 entering the contact becomes thin. Having. (FIG. 2) Therefore, the present invention solves such a problem, and its object is to prevent diffusion of Al and have good wettability with Al, and as a result, high quality and high yield cannot be achieved. It is an object to provide a wiring structure of a semiconductor device.

[Means for solving the problem]

The semiconductor device of the present invention is a diffusion layer region on the surface of a semiconductor substrate, an insulating film provided on the semiconductor substrate, having an opening on the diffusion layer region, and provided on the insulating film and on side and bottom surfaces of the opening. A barrier metal layer made of a refractory metal compound, a silicide layer provided at an interface between the diffusion layer region and the barrier metal layer, and an aluminum alloy wiring layer provided on the barrier metal layer. The surface of the barrier metal layer contains silicon or oxygen.

Further, silicon is contained in a grain boundary of the barrier metal layer.

Further, the barrier metal layer contains oxygen in the grain boundaries.

Further, the method of manufacturing a semiconductor device according to the present invention includes a step of forming a diffusion layer region on a semiconductor substrate surface, a step of forming a liquid-absorptive film on the semiconductor substrate, and forming an opening in the insulating film on the diffusion region. Forming a barrier metal layer made of a refractory metal compound in the opening and on the insulating film, and forming a silicide layer at an interface between the bottom surface of the opening and the diffusion layer region; A step of introducing oxygen or silicon into the surface; and a step of forming an aluminum alloy layer on the barrier metal layer.

Further, the aluminum alloy layer is formed by bias sputtering.

Further, the aluminum alloy layer is formed by bias sputtering in a heated state.

Further, the step of introducing oxygen is performed using oxygen plasma.

〔Example〕

FIG. 1 is a manufacturing process diagram of a semiconductor device according to one embodiment of the present invention. Hereinafter, the present invention will be described with reference to the drawings.
First, as shown in FIG. 1A, an opening is provided in an insulating film 102 on a P-type semiconductor substrate 103, and a high melting point metal (Ti in this embodiment) is used.
Is sputtered. 108 is an N-type diffusion layer. Next, the first
When the refractory metal is heat-treated in nitrogen, as shown in FIG.
6. Titanium nitride 105 (hereinafter referred to as TiN) is formed on the Ti on the insulating film and the Ti surface on the diffusion layer. In this embodiment, the heat treatment is performed in an annealing furnace using a halogen lamp in the range of 700 to 9%.
Performed at a temperature of 00 ° C. Then silicon or oxygen 10
4 is ion-implanted. Oxygen can also be introduced by using oxygen plasma or annealing in a diffusion furnace at a temperature of 400 to 500 ° C. in an atmosphere containing oxygen. afterwards,
As shown in FIG. 1C, an Al alloy wiring 107 was formed by bias sputtering. At this time, when the heating is performed simultaneously with the application of the bias, the coverage of the Al alloy layer in the contact opening is further improved.

Immediately after the TiN is formed by heat-treating Ti, the TiN has a columnar crystal, and there is a grain boundary, and Al is easily diffused therein. As in the present invention, the TiN film 109 introduced with silicon or oxygen is used.
In silicon, silicon and oxygen are present at the grain boundaries, and serve as a diffusion barrier for Al.

FIG. 3 shows a leakage current distribution when silicon is included in TiN at a surface concentration of 1 × 10 ¹⁹ cm ⁻³ or more. Samples N in the N-type diffused layer having 10000 Quai contacts ⁺ / P ^- 5V junction leakage current
It was measured by applying voltage. The upper Al alloy was formed by bias sputtering of forward Al. The sample in which silicon was introduced into TiN (FIG. 3 (b)) has significantly reduced leakage current.

If silicon or oxygen is contained in the TiN surface, the bias-sputtered Al alloy can easily move on the TiN surface, and as a result, the Al alloy can easily enter the contact. The same applies to the sputtering method without bias application. However, in terms of the coverage of the bias-sputtered Al alloy, the present invention provides a first method compared to the prior art shown in FIG.
It is improved as shown in FIG. As a result, when a current is applied to this wiring, the current density in the contact portion in FIG. 1 of the present invention is smaller than that in the related art, and so-called electromigration, which is a reliability defect, is greatly reduced. .

In the above embodiment, heat treatment was performed on Ti as a barrier metal.
Although a description has been given of a method of forming TiN, TiN formed by sputtering Ti in an atmosphere containing nitrogen, a barrier metal obtained by sputtering a TiW target, and the like also have the same effect.

〔The invention's effect〕

As described above, according to the present invention, since oxygen or silicon is contained in the barrier metal surface, junction leakage is unlikely to occur, the coverage of the Al alloy at the contact portion is good, and wiring and electromigration at this portion are good. It is possible to provide a high-quality and high-yield semiconductor device in which the occurrence of the semiconductor device is difficult.

[Brief description of the drawings]

1 (a) to 1 (c) are manufacturing process diagrams showing one embodiment of the present invention. FIG. 2 is a cross-sectional view showing Al coverage of a contact portion according to a conventional technique. 3 (a) and 3 (b) are graphs of junction leakage current distribution showing the effect of the present invention. 101 Ti 102 Insulating film 103 P-type semiconductor substrate 104 Silicon or oxygen 105 TiN 106 Titanium silicide 107 Bias-sputtered Al alloy 108 N-type diffusion layer 109 TiN containing silicon or oxygen

Claims (7)

(57) [Claims] An insulating film provided on the semiconductor substrate, having an opening on the diffusion layer region, and provided on the insulating film and on side and bottom surfaces of the opening. A barrier metal layer made of a high melting point metal compound,
A semiconductor device comprising a silicide layer provided at an interface between the diffusion layer region and the barrier metal layer, and an aluminum alloy wiring layer provided on the barrier metal layer, wherein silicon or oxygen is provided on the surface of the barrier metal layer. A semiconductor device comprising: 2. The semiconductor device according to claim 1, wherein silicon is contained in a grain boundary of said barrier metal layer. 3. The semiconductor device according to claim 1, wherein said barrier metal layer contains oxygen at a grain boundary. A step of forming a diffusion layer region on the surface of the semiconductor substrate; a step of forming an insulating film on the semiconductor substrate; a step of forming an opening in the insulating film on the diffusion layer region; Forming a barrier metal layer made of a refractory metal compound on the insulating film and forming a silicide layer at an interface between the bottom surface of the opening and the diffusion layer region; introducing oxygen or silicon into the surface of the barrier metal layer; And forming an aluminum alloy layer on the barrier metal layer. 5. The method according to claim 4, wherein said aluminum alloy layer is formed by bias sputtering. 6. The method according to claim 4, wherein said aluminum alloy layer is formed by bias sputtering in a heated state. 7. The method according to claim 4, wherein the step of introducing oxygen is performed using oxygen plasma.