JPS61128544A - Semiconductor device - Google Patents

Abstract

PURPOSE:To decrease circuit area and to improve energy efficiency when a fuse is cut, by forming the conductive layer on a substrate through an insulation film to construct the wiring section that connects a fuse which is one part of the redandant circuit with a fuse by means of this conductive layer. CONSTITUTION:A wiring section 12 is constructed on a silicon substrate 7. The wiring section 12 connects a fuse section 11 which is one part of the redandant circuit with a fuse section 11 by means of a conductive layer 10. This layer 10 is formed with polysilicon through a PSG inter layer insulation film 8. And the wiring section 12 corresponds to the conventional node or aluminum wiring. Further, this fuse section 11 and wiring section 12 can be constructed with metal silicide having high-melting point, rather than polisilicon. The circuit area can be reduced, with advantage in layout since no connecting section with conventional aluminum is required. Moreover, a facorable energy efficiency is achieved since the energy of the laser is not conducted to the n<+> diffusion layer through aluminum wiring when the fuse is cut.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device, and particularly to an improvement of a laser-programmed spare decoder in a dynamic memory.

[Conventional technology]

A conventional device of this kind will be explained with reference to FIGS. 3 to 5. FIG. 5 is a circuit diagram of a spare decoder, and in the figure, RAO-RA6. RAO to RAS are address signals, CRDI is a gate signal, and PRD is a precharge signal.

3 shows an example in which the circuit shown in FIG. 5 is actually formed on a semiconductor substrate, and FIG. 4 is a sectional view taken along the line ff-ff in FIG. 3. In the figure, reference numeral 1 denotes a need portion, which is made of polysilicon (Poj!ysL) or the like. Reference numeral 2 denotes a node, which is constituted by an n+ diffusion layer in the semiconductor substrate. 3.4 is an aluminum wiring made of aluminum,
The fuse 1 and the node 2 are connected via an aluminum wiring 3. Reference numeral 5 denotes a transistor, which is connected to the GND line via an n+ diffusion layer 6. The above-mentioned fuse 1 is connected to a transistor 5 via an aluminum wiring 4. 7 is a silicon substrate, 8 is a PSGJ'1iii insulating film, and 9 is a passivation film.

Since the spare decoder shown in FIG. 5 is for relieving a defective line in the memory, it is inactive and not selected as it is. When a defect occurs in a regular line, the decoder shown in Figure 5 is activated and the defective line is replaced with a spare line. Programming is performed by combining fuses 1 to be cut, and by performing programming, a spare decoder corresponding to a defective decoder is configured.

[Problem that the invention seeks to solve]

However, in the conventional configuration, since the fuse portion 1 is connected to the n+ diffusion layer 2 via the aluminum wiring 3, the heat capacity is small, and the laser energy is not efficiently consumed when cutting the fuse.

Furthermore, since the aluminum wiring 3 must be formed, a large area is required, which is disadvantageous in terms of layout.

This invention was made to solve the above-mentioned problems, and aims to provide a semiconductor device that can increase the energy efficiency when cutting a fuse and reduce the area required to form a circuit. There is.

[Means for solving problems]

In the semiconductor device according to the present invention, a conductive layer is formed on a semiconductor substrate via an insulating film, and the conductive layer constitutes fuses that are part of a redundant circuit and a wiring portion that connects the fuses. This is what I did.

[Effect]

In the semiconductor device according to the present invention, since the fuse and the wiring part are integrally molded, the circuit area is small, and unlike the conventional case, heat does not escape to the diffusion layer through the aluminum layer with a small heat capacity, so energy is reduced. High efficiency.

〔Example〕

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

1 and 2 show a semiconductor device according to an embodiment of the present invention, FIG. 1 is a plan view of the device, and FIG. 2 is a sectional view taken along the line 1--2 in FIG. 1. In the figure, Figures 3 to 5
The same reference numerals as in the figure indicate the same parts as in the figure, and 10 is a conductive layer formed using polysilicon on the silicon substrate 7 via the PSG eyebrow insulating film 8, and the conductive layer 10 serves as a redundant circuit. A fuse part 11 that is a fuse part and a wiring part 12 that connects the fuse parts 11 are configured.
corresponds to the conventional node and aluminum wiring (see 2.3 in Figs. 3 and 4). Note that the fuse portion 11 and the wiring portion 12 may be made of refractory metal silicide instead of polysilicon.

Next, the effects will be explained.

In the circuit configuration as described above, the conventional aluminum joint (see 3 in FIG. 3.4) is unnecessary, so the circuit area can be reduced, which is advantageous in terms of layout. In addition, the energy of the laser when cutting the fuse is not transmitted to the n0 diffusion layer (see 2 in Figures 3 and 4) through the aluminum wiring, so energy efficiency is good. Since high melting point silicide has smaller parasitic resistance and parasitic capacitance, the time constant becomes smaller, and the charging and discharging of the decoder becomes faster, leading to more stable and faster operation.

Although the above embodiment has been explained by taking a laser program type spare decoder as an example, it goes without saying that the present invention can also be applied to an electric program type spare decoder or a semiconductor fuse such as a mask ROM.

Further, in the above embodiment, an example was explained in which polysilicon and high melting point metal silicide were used as the material of the integrally formed part.
Similar effects can be obtained when using other silicides or polycides.

〔Effect of the invention〕

As described above, according to the present invention, a conductive layer is formed on a semiconductor substrate via an insulating film, and this conductive layer constitutes fuses that are part of a redundant circuit and a wiring section that connects the fuses. This has the effect of reducing the circuit area and improving the energy efficiency when cutting the fuse.

[Brief explanation of drawings]

FIG. 1 is a plan view of a semiconductor device according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, FIG. 3 is a plan view of a conventional semiconductor device, and FIG. FIG. 5 is a sectional view taken along the line IV--IV in the figure, and is a circuit diagram of the spare decoder. In the figure, 7 is a semiconductor substrate, 8 is an insulating film, 10 is a conductive layer, 1
1 is a fuse section, and 12 is a wiring section. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A semiconductor characterized in that a conductive layer is formed on a semiconductor substrate with an insulating film interposed therebetween, and the conductive layer constitutes a fuse that is part of a redundant circuit and a wiring section that connects the fuses. Device. (2) The semiconductor device according to claim 1, wherein the conductive layer is formed using polysilicon or metal silicide.