JPH0497545A - Semiconductor device with built-in fuse - Google Patents

Abstract

PURPOSE:To reduce a fusing current and to enable use of a part excepting a bent part as a wiring by providing a recessed part in a field insulating film to a polycrystalline silicon film to come into contact with an internal angle of one or more bent parts and by thinning the film partially. CONSTITUTION:At least one or more bent parts are provided to a part which becomes a fuse of a polycrystalline silicon film 3. A field insulating film 5 is partially provided with a recessed part to come into contact with an internal angle of the bent part. Thereby, current concentration effect in the bent part and partial reduction in polycrystalline silicon film thickness due to a foundation step enable blow out of fuse with a small current. The partial reduction in thickness makes it possible to fuse only the bent part and to use the polycrystalline silicon film in other fuse constitution parts as a wiring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device with a built-in fuse, and particularly to a structure of a fuse made of polycrystalline silicon wiring.

[Conventional technology]

Conventionally, semiconductor devices with a built-in fuse, which have a built-in fuse for trimming internal resistance or for redundant circuits, have a structure in which a fuse made of a polycrystalline silicon film is provided on a field insulating film of the same thickness. It became.

[Problem to be solved by the invention]

In the conventional fuse-embedded semiconductor device described above, as shown in FIG. ing. Further, in order to prevent damage due to heat, a window 8 is provided by partially removing the glabella insulating film 4 and passivation film 9 above the fuse. This structure has the disadvantage that since the polycrystalline silicon wiring in the portion forming the fuse is blown out, it merely functions as a fuse and cannot be used as wiring.

[Means to solve the problem]

A semiconductor device with a built-in fuse of the present invention uses a polycrystalline silicon film as a fuse material, has one or more bent portions on the fuse, and has a field formed at a corner of the bent portion so as to be in contact with an inner corner of the bent portion. By providing a concave portion in the insulating film, a step is provided and a means for partially reducing the thickness of the polycrystalline silicon film is provided. Therefore, the fusing current is smaller than that of a normal polycrystalline silicon wiring, and since the fusing part is a bent part, the polycrystalline silicon film other than the bent part can be used as a wiring.

〔Example〕

Next, the present invention will be explained with reference to the drawings. FIG. 1(a) is a plan view of one embodiment of the present invention, and FIG. 1(b) is a sectional view taken along the line A--A in FIG. 1(a).

Reference numeral 3 denotes a polycrystalline silicon film, which has at least one bent portion in a portion that will become a fuse, and a recess is partially provided in the field insulation wA5 so as to be in contact with an inner corner of the bent portion. By using the above method, it is possible to cut the fuse with a current smaller than the normal polycrystalline silicon fusing current due to the effect of current concentration at the bend and the partial reduction in the thickness of the polycrystalline silicon film due to the step difference in the base. It is said that

Note that if the thickness of the recess in the field insulating film 5 is not sufficient, a diffusion layer 1 of a different conductivity type (for example, a P well in the case of an N-type substrate) is provided on the semiconductor substrate 6 below the bend, and the field insulating film 5 is Insulation failure due to cracks, etc. in step 5 should be prevented.

〔Effect of the invention〕

As explained above, the present invention uses a polycrystalline silicon film as a fuse material, provides a bent part, and partially reduces the thickness of the polycrystalline silicon film due to current concentration and step differences in the base, so that only the bent part is fused. However, there is an advantage that the polycrystalline silicon film of other fuse constituent parts can be used as wiring.

[Brief explanation of drawings]

FIG. 1(a) is a plan view of a semiconductor chip showing an embodiment of the present invention, FIG. 1(b) is a cross-sectional view taken along line A-A in FIG. 1(a), and FIG. 2(a) is a FIG. 2(b), which is a plan view of a conventional semiconductor chip, is a sectional view taken along the line A--A in FIG. 2(a). 1... Diffusion layer, 2... Aluminum wiring, 3...
Polycrystalline silicon film, 4... Interlayer insulating film, 5... Field insulating film, 6... Semiconductor substrate, 7... Contact, 8... Passivation film.

Claims (1)

[Claims] It has a fuse that is made of a polycrystalline silicon film provided on a field insulating film formed on one main surface of a semiconductor substrate and is blown by a current, and the fuse has one or more bent portions, and the fuse has one or more bent portions. A semiconductor device with a built-in fuse, characterized in that a recess is provided in the field insulating film at least below an inner corner.