JPH0680659B2 - Wiring structure for semiconductor device and manufacturing method thereof - Google Patents

Description

The present invention relates to a wiring structure of a semiconductor device, and more particularly to a wiring structure having a fine dimension and a method for manufacturing the same.

[Conventional technology]

High integration in semiconductor devices, especially in semiconductor integrated circuits
Development is proceeding in the direction of speeding up. Therefore, it is important to miniaturize and speed up active elements such as transistors, and miniaturize and reduce loss of a wiring structure used for electric signal transmission and power feeding / grounding. In other words, the wiring resistance of the wiring structure causes attenuation of the transmitted signal in the signal wiring, a voltage drop in the power supply wiring, and a fluctuation in the ground potential in the ground wiring, which is possible. It is necessary to reduce as much as possible. In addition, the wiring capacitance also causes attenuation and delay of high-speed and high-frequency signals, so reduction is necessary. Further, the capacitance between wirings adjacent to each other on the same plane and the capacitance between multi-layer wirings also cause signal crosstalk, and therefore need to be reduced.

FIG. 2 is a view showing a cross section perpendicular to the current direction of a conventional wiring structure. In the figure, the base 21 is made of a semiconductor substrate such as Si or GaAs having an insulating surface, and the wiring 22 is
It is made of a material having good conductivity such as Al or Au. The wiring 22 has a substantially rectangular cross section, and its width W direction is arranged parallel to the base 21.

In such a structure, the wiring resistance has been conventionally reduced by selecting a low specific resistance material as the wiring material and widening the wiring thickness t or the wiring width w. Further, the wiring capacity has been reduced by reducing the area facing the base 21, that is, by reducing the width w of the wiring.

(Problems to be Solved by the Invention) Such a conventional wiring structure has the following problems. That is, widening the width w of the wiring to reduce the wiring resistance increases the wiring capacitance and makes it difficult to increase the collecting degree of the collecting circuit and reduce the chip size. In order to avoid these problems, it is necessary to increase the thickness-width ratio of the wiring cross section, that is, the aspect ratio t / w. Wiring is easily peeled off due to. To reduce the width, EB
Since an apparatus for drawing a fine pattern by an exposure apparatus or the like and for accurately etching in the thickness direction is required, throughput is lowered, productivity is lowered, and production cost is increased.

An object of the present invention is to solve the above-mentioned problems, and to provide a wiring structure capable of reducing the wiring resistance without increasing the wiring capacitance and decreasing the degree of accumulation, and a manufacturing method by an extremely simple process. Especially.

[Means for solving problems]

The wiring structure of the present invention includes a base of a semiconductor device, an insulative support having a side surface formed on the base and having an inclination with respect to a main surface of the base, and an insulating support on the side surface of the support. A method of manufacturing the same includes a formed metal film and an insulating film formed on the metal film, and an insulating support having a side surface having an inclination with respect to a main surface of a base of a semiconductor device. Forming a metal film and an insulating film on the main surface of the base body including the support in order, and forming the insulating film on the metal film parallel to the main surface of the base body with the main film. Removing by an etching means having anisotropy in the direction perpendicular to the surface to form an insulating side wall on the metal film on the side surface of the support, and the exposed portion of the metal film using the side wall as a mask Is removed by etching.

[Action]

In the wiring structure according to the present invention, the width direction of the wiring structure is formed obliquely with respect to the one main surface of the base body, so that the effective cross-sectional area of the wiring is smaller than that of the conventional wiring structure having the same plane dimension. Can be widely taken. Further, since the surface facing the substrate or other wiring is inclined, the wiring capacitance generated between the substrate or other wiring can be reduced.

〔Example〕

 Hereinafter, the present invention will be described with reference to the drawings.

1 (a), (b), (c), and (d) are cross-sectional views showing an embodiment of a wiring structure of a semiconductor device and a method of manufacturing the same according to the present invention. Each drawing shows a cross section in the direction perpendicular to the direction of the current flowing through the wiring structure.

First, in FIG. 1 (a), an insulating film such as SiO ₂ or Si ₃ N ₄ is formed on a substrate 11 made of a semiconductor such as Si or GaAs,
The insulating film is wet-etched using a photoresist mask 14 having a predetermined pattern. Then, the insulating support material 13 having side surfaces inclined with respect to the base 11 is formed by utilizing the undercut generated during the etching. For etching, for example, when the insulating film is SiO _2, a hydrofluoric acid-based etchant is suitable. The inclination angle θ and the width w of the side surface of the insulating support material 13 depend on the etching conditions and the insulating support material 13.
Controlled by the thickness of. The inclination angle θ is preferably about 45 °
It is better to set to.

Next, as shown in FIG. 1 (b), a photoresist mask
After removing 14, the wiring gold film 15 made of Au or Al is sputtered or vapor-deposited on the substrate 11 including the insulating support material 13 so that the side surface of the insulating support material 13 has a predetermined thickness t. The film is formed by a method or the like. Further, an insulating film 16 such as SiO ₂ or Si ₃ N ₄ is formed so as to cover the wiring metal film 15 by a sputtering method or a chemical vapor deposition method.

Further, as shown in FIG. 1 (c), CF ₄
The insulating film 16 on the flat surface portion parallel to one main surface of the substrate 11 is selectively removed by anisotropic etching by reactive dry etching using gas or the like, and insulation is provided only on the side surface on the insulating support material 13. Forming a side wall 16a.

Finally, as shown in FIG. 1D, the exposed region of the wiring metal film 15 is removed by etching by ion milling or the like using the insulating side wall 16a as a mask. In this way, the wiring 15a having the plane dimension w is formed. Insulating side wall 16a
May be removed if necessary.

Through the above steps, the wiring structure in which the width w ¹ direction is inclined by the angle θ with respect to the one main surface of the base 11 is completed. Since the width w ¹ of such a wiring structure is given by w / cos θ, its cross-sectional area is approximately w · t / cos θ. Therefore, the plane dimensions are the same (width
w, thickness t) 1 / co when compared with the cross-sectional area of the conventional wiring structure
A cross-sectional area as large as sθ (| cosθ | <1) is obtained. It should be noted that if the tilt angle θ is increased, the above-described improvement effect can be increased, but it becomes difficult to deposit the wiring metal film 15 with good controllability, so that θ is about 45 ° as described above. desirable.

In FIG. 1, a method using undercut in a wet etching method is shown as a method of forming the insulating support material 13 having a side surface inclined with respect to the substrate 11, but as another method, a photoresist having a predetermined pattern or the like is used. It is also possible to use the sagging at the end of the pattern that occurs when the organic substance is heat-treated at a high temperature. That is, the organic substance is used as an insulating support material.
It may be directly used as 13, or the sag of the pattern end may be transferred to another insulating film, and the insulating film may be used as the insulating support material 13. As another method, the insulating support material 13 may be formed by a taper etching method using an ion beam obliquely incident on the substrate 11.

[Effects of the Invention] As described above, according to the present invention, since wiring is formed on the inclined side surface of the insulating support material, a fine wiring structure can be realized very easily. Moreover, since the width direction of the wiring is formed obliquely with respect to the base, the wiring resistance is reduced due to the large effective cross-sectional area of the wiring, and the opposing surface to the base or other wiring is inclined. Alternatively, the wiring capacitance generated between other wirings can be reduced. Therefore, the semiconductor collecting circuit can be improved in collecting performance, high-speed performance, and stability.

[Brief description of drawings]

FIG. 1 is a process sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional wiring structure. 11 ... Base, 13 ... Insulating support material, 15 ... Wiring metal film, 15a ... Wiring, 16a ... Insulating side wall.

Claims (2)

[Claims] 1. A base of a semiconductor device, an insulative support having a side surface formed on the base and having an inclination with respect to a main surface of the base, and a metal formed on the side surface of the support. A wiring structure for a semiconductor device, comprising: a film. 2. A step of forming an insulative support having a side surface inclined with respect to a main surface of a base of a semiconductor device on the base, and a metal film on the main surface of the base including the support. And a step of sequentially stacking insulating films, and removing the insulating film on the metal film parallel to the main surface of the base by etching means having anisotropy in a direction perpendicular to the main surface, And a step of forming an insulating side wall on the metal film on the side surface, and a step of etching and removing an exposed portion of the metal film using the side wall as a mask. Body manufacturing method.