JPH02275633A - Semiconductor integrated circuit - Google Patents

Abstract

PURPOSE:To lower electric resistance and current density in a joining section on a semiconductor substrate by forming a trench to a metallic wiring and the joining section and spreading the area of joining. CONSTITUTION:An inter-layer insulating film 3a is shaped onto a silicon substrate 1a, and a diffusion layer 2a is formed. The silicon substrate 1a is etched while using the contact hole 5a of the inter-layer insulating film 3a as a mask and a trench 6a is shaped, and a metallic wiring 4a is grown and the trench 6a is buried. Consequently, the diffusion layer 2a and the metallic wiring 4a are brought into contact on the surface of the trench 6a, thus increasing a contact area. Accordingly, electric resistance in a joining section is lowered, and current density is reduced, thus preventing the generation of electro- migration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor integrated circuit, and particularly to the shape of a joint between a metal wiring and a diffusion layer of a semiconductor substrate.

[Conventional technology]

In a conventional semiconductor integrated circuit, the shape of a junction between a metal wiring and a diffusion layer of a silicon substrate has a planar structure as shown in FIG.

[Problem to be solved by the invention]

Since the above-described conventional bonding portion between the metal wiring and the diffusion layer on the silicon substrate has a planar shape, the bonding area has been decreasing with the development of microfabrication technology. In addition, as a result, the shape of the joint portion (contact hole) has deteriorated.

Therefore, there are problems such as an increase in electrical resistance at the junction, resulting in poor characteristics, and an increase in current density, which tends to cause electromigration.

[Means to solve the problem]

A semiconductor integrated circuit of the present invention includes an insulating film provided on a semiconductor substrate, and a metal wiring that contacts a predetermined portion of the semiconductor substrate through a contact hole provided in the insulating film. A trench is provided in the contact hole of the semiconductor substrate, and the metal wiring buries the trench.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a sectional view of a semiconductor chip showing a first embodiment of the present invention. An interlayer insulating film 3a is formed on a silicon substrate 1a, and a diffusion layer 2a is formed. Next, using the contact hole 5a of the interlayer insulating film 3a as a mask, the silicon substrate 1a is etched to form a trench 6a, and then a metal wiring 4a is grown to fill the trench 6a.

Since the diffusion M2a and the metal wiring 4a are in contact with each other on the surface of the trench 6a, a large contact area can be obtained.

FIG. 2 is a sectional view of a semiconductor chip showing a second embodiment of the present invention.

A glabellar insulating film 3b is grown on the silicon substrate 1b, and the silicon substrate at the joint portion is etched to form a trench 6b. At this time, a contact hole 5b is formed in the interlayer insulating film 3b. Next, a diffusion layer 2b is formed along the outer periphery of the trench, and then a metal wiring 4b is grown.

In this embodiment, the thickness of the diffusion layer is constant when viewed from the surface of the wrench, and there is no contact between the metal wiring and the semiconductor portion other than the diffusion layer, so there is an advantage that contact can be made more reliably.

〔Effect of the invention〕

As explained above, in the present invention, by providing a trench at the joint between the metal wiring and the semiconductor substrate, the joint area can be expanded and the shape of the joint can be improved accordingly. Therefore, the electrical resistance at the junction can be reduced, and the current density can be reduced, making it possible to improve the characteristics and reliability of the semiconductor integrated circuit.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a semiconductor chip showing a first embodiment of the present invention, FIG. 2 is a sectional view of a semiconductor chip showing a second embodiment of the present invention, and FIG. 3 is a sectional view of a semiconductor chip showing a conventional example. be. 1, la, lb - silicon substrate, 2.2a. 2b...diffusion layer, 3.3a, 3b... interlayer insulating film,
4.4a, 4b...-metal wiring, 5.5a, 5b...
Contact hole, 6a 6b...trench.

Claims (1)

[Claims] In a semiconductor integrated circuit having an insulating film provided on a semiconductor substrate, and a metal wiring that contacts a predetermined portion of the semiconductor substrate through a contact hole provided in the insulating film,
A semiconductor integrated circuit comprising a trench provided in the contact hole of the semiconductor substrate, and the metal wiring embeds the trench.