JPH04332131A - Semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a metal wiring made of crystalline grains having rigid bondability by forming an uneven surface in which an angle formed between surfaces on a silicon oxide film is the same as an angle formed of crystalline surfaces of a metal crystal, and forming the wiring made of the grains on the uneven surface. CONSTITUTION:An uneven surface is fomed on an Si substrate 3 formed with an SiO2 film 2. For example, a length of one side of one surface of the uneven surface is, 1mum, and an angle formed between the surfaces is set to 141.058 degrees of twice as large as an angle formed at crystalline surface plane ¦111]of an Al crystalline grain. Then, after an Al solid film is vapor-deposited, an Al wiring 1 is patterned. Thus, since a grain boundary of the metal crystal for constituting the wiring coincides with trough or crest of the uneven surface of the silicon oxide film, the wiring having rigid bondability in which a disconnection scarcely occurs, can be formed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor devices, and more particularly to the structure of wiring made of polycrystalline thin films.

0002

2. Description of the Related Art Hitherto, a method has been proposed and attempted in which a polycrystalline thin film is formed on an insulating layer and then patterned for fine wiring in a semiconductor device.

0003

[Problems to be Solved by the Invention] However, when the layer directly below the wiring to be formed is a flat plate, the polycrystalline thin film wiring formed thereon is
EEE International Relia
bilty physics symposium
) (1986), p. 253 of the conference proceedings, as reported by Hartmann Hieber et al., the direction of the crystal grains tends to be aligned in the direction perpendicular to the layer immediately below the wiring. However, due to the interaction between the crystal grains, the directions of the crystal grains are not perfectly aligned, and the grain boundaries do not become specific crystal planes. For this reason, wires manufactured by conventional methods, whose width is approximately the same size as crystal grains, have a drawback in that they have a small yield stress value with respect to tensile or compressive stress, resulting in wire breakage and the like.

0004

[Means for Solving the Problems] A semiconductor device of the present invention includes:
A silicon oxide film formed on a semiconductor substrate, an uneven surface formed on the surface of this silicon oxide film whose angle between the surfaces is the same as an angle formed by a crystal plane of a metal crystal, and a surface on this uneven surface. This includes wiring made of metal crystals formed in

[0005]

[Operation] As a general property, the direction of a specific crystal plane of a crystal grain is perpendicular to the substrate, so if the substrate has unevenness, the direction of the crystal grain is perpendicular to each surface of the unevenness. The direction of a certain crystal plane will be oriented. If the size of this unevenness is made to be about the size of a crystal grain, only one crystal grain will grow on each uneven surface if the width of the wiring is about the same as the size of the crystal grain. If the angle between this uneven surface and the surface matches the angle between a certain crystal plane and the surface,
The crystal grains growing on it will stick together with neighboring crystal grains at certain crystal planes.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to the drawings. Figure 1
1 is a sectional view of one embodiment of the present invention.

[0007] SiO2 with a thickness of about 0.5 μm was formed by thermal oxidation.
An example will be described in which an A1 wiring 1 is formed by sputtering on a Si substrate 1 on which a film 2 is formed. SiO2
The film 2 has an uneven surface, and the length of one side of one of the uneven surfaces is 1 μm. The angle between the planes is twice the angle formed by the [111] crystal plane of the Al crystal grain, 141.
It is set to 058 degrees. The unevenness is formed by obliquely irradiating a 1 kW electron beam using a Ta plate having a pattern of 1 μm width as a mask. Next, after depositing a solid Al film by sputtering, patterning of Al wiring by wet or dry etching was performed.
When alloying is carried out for 30 minutes at ℃, the crystal grains grow, and the orientation relationship of the crystal planes of the crystal grains 4 in the Al wiring 1 is realized as shown in FIG. It is connected to neighboring crystal grains through the crystal planes. Therefore, an Al wiring with strong grain boundary bonding can be formed.

[0008] The Al according to this embodiment configured as described above
In the wiring, the grain boundaries coincide with the valleys or peaks of the unevenness, and the grain boundaries combine at specific crystal planes. Using this method, in the case of Al wiring, 500°C, 100°C
After annealing for about an hour, the parts that were cut in the conventional example no longer cut.

[0009] In the above embodiment, the case where Al was used as the metal forming the wiring was explained, but S
An Al alloy containing i and Cu or W can be used.

0010

As explained above, according to the present invention, the grain boundaries of the metal crystals constituting the wiring coincide with the valleys or peaks of the unevenness on the surface of the silicon oxide film. A semiconductor device having strong metal wiring can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention.

FIG. 2 is a diagram showing the orientation relationship of crystal grains in Al wiring.

[Explanation of symbols]

1 Al wiring 2 SiO2 film 3 Si substrate 4 Al crystal grains

Claims (1)

[Claims] 1. A silicon oxide film formed on a semiconductor substrate, and an uneven surface formed on the surface of the silicon oxide film, the angle between the surfaces being the same as the angle formed by the crystal plane of a metal crystal. , and wiring made of metal crystal formed on the uneven surface.