JP3063165B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a structure of a contact hole in a semiconductor device.

[0002]

2. Description of the Related Art As shown in FIG. 8, in general, a diffusion layer (not shown) formed on the surface of a silicon substrate 301 and a tungsten wiring 305 as a wiring are connected via a contact hole 310 as a connection hole. It is connected. Oxide film 301 on silicon substrate 301, B excellent in flattening
An interlayer film 302 such as PSG is provided, and a contact hole 310 is formed by opening the interlayer film 302 and the oxide film 301 in a predetermined region. Contact hole 3
10 surface of silicon substrate 301 at bottom and interlayer film 302
On the surface, an adhesive layer (hereinafter referred to as an adhesion layer) 304a made of titanium nitride (TiN) or the like for enhancing the adhesion between the wiring such as the tungsten wiring 305 and the base and the like.
304b are formed. Tungsten wiring 305
Is hydrogen (H2) of tungsten hexafluoride (WF6) gas
It is formed by a reduction reaction with a gas.

[0003]

When only the diameter of the contact hole is reduced without reducing the thickness of the interlayer film, the aspect ratio of the contact hole generally increases. As a technique for embedding a wiring material into such a contact hole having a high aspect ratio, a method of forming a tungsten film by a CVD method is widely used. However, a tungsten film having a large contact area with a silicon-based oxide film has poor adhesion to the silicon-based oxide film due to thermal stress. Therefore, an adhesion layer of titanium nitride (TiN) or the like is formed under the tungsten film.

However, since an adhesion layer such as titanium nitride is usually formed by a sputtering method, the step coverage in a contact hole having a high aspect ratio is poor, and the adhesion layer does not adhere to the side wall deep in the contact hole. Parts arise. Therefore, tungsten is deposited on a portion having an adhesion layer such as the bottom surface of a contact hole, but tungsten is not formed on a portion without an adhesion layer. As a result, a tungsten wiring 305 is formed as shown in FIG. Holes 306 that are not formed are formed, causing variations in the contact resistance value, and in extreme cases, the tungsten wiring 305 is disconnected.

[0005]

According to the present invention, there is provided a semiconductor device comprising:
An insulating film formed on a substrate, a contact hole provided in a predetermined region of the insulating film, and a first conductor layer provided on a side wall of the contact hole;
Wherein the conductive layer is provided on the substrate via the insulating film. Further, the method for manufacturing a semiconductor device according to the present invention includes a step of forming a first conductor layer on a part of a substrate, and a step of forming an insulating film on the substrate surface and the first conductor layer surface. Forming a contact hole penetrating the insulating film on the first conductor layer and the first conductor layer, and forming a second conductor layer in the contact hole. It is characterized by.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view for explaining a first embodiment of the present invention. In this embodiment, tungsten is used as a wiring material by CVD. Silicon substrate 101
The conductor layer 120b provided on the upper oxide film 102 includes:
The side wall of the contact hole 110 is formed. Although no adhesion layer is formed on the side wall of the contact hole 110 formed by the conductor layer 120b, the contact hole 110 formed by the bottom surface of the contact hole 110 and the interlayer film 103 made of a BPSG film or the like having excellent flatness is formed. Adhesion layers 104a and 104b made of, for example, titanium nitride are formed on the side wall portions. For this reason, the deposition property (adhesion property) of the tungsten wiring 105 on the contact hole 110 is improved, and no vacancy occurs on the side wall of the contact hole 110.

A manufacturing process for obtaining the structure of this embodiment will be described with reference to FIGS. First, the silicon substrate 101
After forming elements such as a MOS transistor (not shown) and a bipolar transistor (not shown) on the surface,
The surface of the silicon substrate 101 is covered with an oxide film 102 of about 0 nm. Further, a conductor layer 120 made of, for example, a polycrystalline silicon film of about 400 nm in which phosphorus is diffused is formed (FIG. 2). Next, the conductor layer 120 is dry-etched using the photoresist film 108 as a mask to form the conductor layer 1.
20a is formed (FIG. 3). Next, BP with excellent flattening
An interlayer film 103 made of an SG film or the like is formed to a thickness of about 500 nm, and heat treatment for planarization is performed [fourth]. Next, using the photoresist film 109 as a mask, first, the conductor layer 1 is formed.
The interlayer film 103 on the top surface 20a is isotropically etched with diluted hydrofluoric acid, and then the conductive layer 120a and the oxide film 102 are anisotropically etched to form contact holes 110.
Then, a conductor layer 120b is formed (FIG. 5).

Thereafter, adhesion layers 104a and 104b made of titanium nitride or the like are formed by a sputtering method,
Tungsten hexafluoride (WF6) gas of hydrogen (H2
1) A tungsten film is deposited by a CVD method using a reduction reaction with a gas, is patterned to form a tungsten wiring 105, and unnecessary portions of the adhesion layer 104b are removed by etching using the tungsten wiring 105 as a mask. Forming device.

FIG. 6 is a sectional view for explaining a second embodiment of the present invention. In this embodiment, an aluminum wiring 206 is used as the wiring. The conductor layer 220 provided on the oxide film 202 on the silicon substrate 201 forms a side wall of the contact hole 210. Although no adhesion layer is formed on the side wall of the contact hole 210 formed by the conductor layer 220, the contact hole 2
Adhesion layers 204a and 204b made of, for example, titanium nitride or the like are formed on the bottom surface of the contact hole 10 and the side wall of the contact hole 210 formed by the interlayer film 203. Conductor layer 220 in contact hole 210
In the portion surrounded by, tungsten 205 which is the second conductive layer is buried. In the present embodiment, by changing the wiring from tungsten to aluminum, the conductivity of the wiring is five times that of the first embodiment of the present invention.

[0011]

As described above, according to the present invention, by providing a conductor layer on the side wall of the contact hole, even if an adhesion layer such as titanium nitride is not formed on the side wall of the contact hole, the present invention provides an empty space in the contact hole. Wiring can be formed by tungsten by a normal CVD method without forming a hole.

For example, as shown in FIG.
Taking the example of Example as an example and comparing the contact resistance with the conventional semiconductor device contact hole structure with respect to the contact hole diameter, it is effective for the variation and increase of the contact resistance when the contact hole diameter is about 1 μm. Is clear.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a first embodiment of the present invention.

FIG. 2 is a cross-sectional view for explaining a manufacturing method for obtaining a structure according to a first embodiment of the present invention.

FIG. 3 is a cross-sectional view for explaining a manufacturing method for obtaining the structure of the first embodiment of the present invention.

FIG. 4 is a cross-sectional view for explaining a manufacturing method for obtaining the structure of the first embodiment of the present invention.

FIG. 5 is a cross-sectional view for explaining a manufacturing method for obtaining the structure of the first embodiment of the present invention.

FIG. 6 is a sectional view for explaining a second embodiment of the present invention.

FIG. 7 is a graph for explaining the effect of the first embodiment of the present invention.

FIG. 8 is a sectional view illustrating a contact hole structure in a conventional semiconductor device.

[Explanation of symbols]

101, 201, 301 Silicon substrates 102, 202, 302 Oxide films 103, 203, 303 Interlayer films 104a, 104b, 204a, 204b, 304a,
304b Adhesion layer 105,305 Tungsten wiring 108,109 Photoresist film 110,210,310 Contact hole 120,120a, 120b Conductor layer 205 Tungsten 206 Aluminum wiring 306 Vacancy

Claims (6)

(57) [Claims] An insulating film formed on a substrate, a contact hole provided in a predetermined region of the insulating film, and a first conductor layer provided on a side wall of the contact hole. A semiconductor device, wherein a first conductor layer is provided on the substrate via the insulating film. A second buried contact hole buried in the contact hole;
2. The semiconductor device according to claim 1, further comprising: 3. A step of forming a first conductor layer on a part of a substrate, a step of forming an insulating film on the surface of the substrate and the surface of the first conductor layer, and A step of forming a contact hole penetrating an insulating film on the layer and the first conductor layer; and a step of forming a second conductor layer in the contact hole. Production method. 4. The method according to claim 3, further comprising the step of forming an adhesive layer on said insulating film. 5. The method according to claim 3, wherein said second conductor layer is made of tungsten. 6. A part of the insulating film on the first conductor layer is isotropically etched, and the part of the insulating film on the first conductor layer and the first conductor layer are further etched. 4. The method according to claim 3, wherein the contact hole is formed by anisotropic etching.