JPH0684910A - Method of manufacturing semiconductor device - Google Patents

Abstract

PURPOSE:To manufacture a semiconductor device having high reliability in spite of a fineness by a method wherein a diameter of a connection bore is made small and further a reaction between a metallic layer within the connection bore and a conductive region is prevented. CONSTITUTION:After a tapering connection bore 14 is formed in an insulation film 12, and a barrier metal layer 15 and a metallic layer 16 are formed on the entire surface, the metallic layer 16 having a vertical shape and a barrier metal layer 15 are left on only the bottom of the connection bore 14. Thereafter, a liquefied insulation material is applied thereto to fill the connection bore 14 therewith to harden this insulation material to form an insulation film 18. Therefore, a diameter of the connection bore 14 can be made small and also a covering ratio of the barrier metal layer 15 to the connection bore 14 is high to enhance barrier effects. Further, the connection bore 14 can be readily filled with the insulation film 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device in which a contact hole is filled with a barrier metal layer and a metal layer.

[0002]

2. Description of the Related Art In recent years, with the miniaturization of semiconductor devices, the diameter of connection holes has become smaller. However, since the film thickness of the interlayer insulating film has not changed in order to secure the withstand voltage, the connection holes are not changed. The aspect ratio is increasing.
For this reason, in a wiring such as an Al wiring which originally has a poor step coverage, a conduction failure is likely to occur in the connection hole, and the reliability of the semiconductor device is becoming low.

Therefore, a barrier metal layer is formed by filling the contact hole with a metal layer such as a tungsten layer, preventing the reaction between the metal layer and the semiconductor substrate, and improving the adhesion between the metal layer and the interlayer insulating film. Is used as the base of the metal layer.

[0004]

The barrier metal layer is formed by sputtering or CVD. When the aspect ratio of the contact hole becomes large as described above, the coverage of the barrier metal layer with respect to the contact hole also decreases. The barrier effect is decreasing. As a result, a reaction between the metal layer and the semiconductor substrate or the like occurs, making it difficult to manufacture a highly reliable semiconductor device.

Therefore, according to the present invention, the diameter of the connection hole can be reduced, and the reaction between the metal layer in the connection hole and the conductive region can be prevented even though the connection hole is fine. An object of the present invention is to provide a high manufacturing method of a semiconductor device.

[0006]

According to a method of manufacturing a semiconductor device of the present invention, an inner wall surface of a first insulating film on a conductive region is inclined so that it reaches the conductive region and expands outward. Forming a connection hole, a second step of sequentially forming a barrier metal layer and a metal layer after forming the connection hole, and a metal layer and a barrier metal layer on the bottom of the connection hole. And a fourth step of filling a space between the metal layer and the barrier metal layer left only on the bottom and the inner wall surface with the second insulating film.

A method of manufacturing a semiconductor device according to the present invention is
In the above-described manufacturing method, a liquid insulating material is filled between the metal layer and the barrier metal layer left only on the bottom and the inner wall surface, and the liquid insulating material is solidified to form a second insulating film. It is a thing.

[0008]

In the method of manufacturing a semiconductor device of the present invention, the inner wall surface of the connection hole is inclined so as to widen outward. Therefore, even if the diameter of the connection hole is small, the barrier metal layer for the connection hole is formed. High coverage. Therefore, the barrier effect of the barrier metal layer is high, and the reaction between the metal layer in the connection hole and the conductive region can be prevented.

Although the inner wall surface of the connection hole is widened outward, the second insulating film fills the space between the inner wall surface and the metal layer and barrier metal layer left only on the bottom of the connection hole. Therefore, the diameter of the connection hole can be reduced.

Further, according to the method of manufacturing a semiconductor device of the present invention, a liquid insulating material is filled between the metal layer and the barrier metal layer left only on the bottom of the connection hole and the inner wall surface, and the liquid insulating material is solidified. Since the second insulating film is used, even if the diameter of the connection hole is small, the space between the metal layer and the barrier metal layer and the inner wall surface can be easily filled with the insulating film.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In this embodiment, as shown in FIG. 1A, a silicon substrate 11 having a diffusion layer formed thereon is covered with an insulating film 12, and the insulating film 12 is subjected to a conventionally known taper etching or the like. A connection hole 14 is formed in which the inner wall surface 13 is inclined so as to reach the diffusion layer and spread outward.

Next, a barrier metal layer 15 is formed on the entire surface by sputtering or CVD as shown in FIG. 1 (b). As the barrier metal layer 15, a titanium layer, a titanium silicide layer, a titanium nitride layer, a titanium-tungsten alloy layer, and a composite layer composed of a combination of two or more thereof are used.

Next, as shown in FIG. 1 (c), the connection hole 1
A metal layer 16 is formed on the entire surface of the barrier metal layer 15 so as to bury 4 therein. A tungsten layer or the like is used as the metal layer 16.

Next, as shown in FIG. 1D, the metal layer 1
6 is coated with a resist 17, and patterning is performed so that only a portion of the resist 17 on the bottom of the connection hole 14 is left. Then, using the resist 17 as a mask, the metal layer 1
6 and the barrier metal layer 15 are anisotropically etched to leave the vertically-shaped metal layer 16 and the barrier metal layer 15 only on the bottom of the connection hole 14.

Next, as shown in FIG. 1E, after removing the resist 17, a liquid insulating material such as an SOG solution is applied to fill the connection holes 14, and the insulating material is baked. The insulating film 18 is formed by solidifying.

Next, a resist (not shown) is spin-coated to make the entire surface flat, and the entire surface of the resist, the metal layer 16 and the insulating film 18 is etched back under the same etching rate. Then, as shown in FIG.
The metal layer 16 and the insulating films 12 and 18 are flattened.

The flattening step shown in FIG. 1F is not always necessary. Further, although the diffusion layer in the silicon substrate 11 is used as the conductive region in the above embodiments, the polycrystalline silicon film on the silicon substrate 11 is used as the conductive region, and the connection hole for this polycrystalline silicon film is formed with the barrier metal layer and the metal layer. The present invention can be applied to the manufacture of a semiconductor device having a structure filled with

[0018]

According to the method of manufacturing a semiconductor device of the present invention, since the diameter of the connection hole can be made small, the reaction between the metal layer in the connection hole and the conductive region can be prevented even though it is fine. Since this can be prevented, a highly reliable semiconductor device can be manufactured.

Further, in the method for manufacturing a semiconductor device of the present invention, since it is possible to easily fill the gap between the metal layer and the barrier metal layer left only on the bottom of the connection hole and the inner wall surface with the insulating film, it is possible to form a fine structure. Despite this, a highly reliable semiconductor device can be efficiently manufactured.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention in the order of steps.

[Explanation of symbols]

 12 Insulating film 13 Inner wall surface 14 Connection hole 15 Barrier metal layer 16 Metal layer 18 Insulating film

Claims (2)

[Claims] 1. A first step of forming, in a first insulating film on a conductive region, a connection hole whose inner wall surface is inclined so as to reach the conductive region and spread outward. A second step of sequentially laminating a barrier metal layer and a metal layer after forming the connection hole, and a third step of leaving the metal layer and the barrier metal layer only on the bottom of the connection hole, And a fourth step of filling a space between the metal layer and the barrier metal layer left only on the bottom and the inner wall surface with a second insulating film. 2. A liquid insulating material is filled between the metal layer and the barrier metal layer left only on the bottom and the inner wall surface, and the liquid insulating material is solidified to form the second insulating material. The method of manufacturing a semiconductor device according to claim 1, wherein an insulating film is formed.