JPH0451563A - Semiconductor device - Google Patents

Abstract

PURPOSE:To display a fuse function by ensuring its reliability, at a low cost and surely without a need for a specific process among standard processes by a method wherein a resistance which connects a first interconnection metal to a second interconnection metal via contacts is formed and the central part of the resistance is formed of a thin part which forms an acute angle to low- resistance parts of the contact parts. CONSTITUTION:Contacts 12, 12 are installed respectively on opposite Al interconnections 10, 10; the interconnections are connected by low-resistance parts 13, 13 and a high-resistance part 11 of polysilicon. The high-resistance part 11 forms an acute angle to the low-resistance parts 13, 13. Thereby, an electric field is concentrated very much in parts 14, 15 and also a heat value is concentrated. Consequently, the parts are especially easy to blow. When blowing parts are easy to cause at the specific parts in this manner, it is possible to reduce an energy required for a blowing operation. When such a fuse is used, it is not required to add a specific process newly. Even the fuse of only several bits can be formed in a sufficiently good cost-to-performance ratio and at a low cost.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a fuse circuit for a semiconductor integrated circuit.

[Conventional technology]

In a semiconductor integrated circuit (hereinafter referred to as IC), the characteristics and functions of IC may be changed by performing some kind of operation from outside the IC. For example, programmable
Logic devices and FROMs allow users to achieve desired functionality through write operations. Furthermore, when matching the characteristics of an analogue C, there are some that allow the characteristics to be matched by operations specific to the analogue C. In this way, when adjusting or changing the function after the construction C is completed, the conventional technology is
There was AMO8 and Hughes. Fuses include conventional bipolar PR-OM and programmable logic.
In devices, metals that sublimate easily -N i Or;
T i W, P t S i, etc. are used. Third
The figure shows a typical fuse circuit. Here''Q 40 is the AL wiring, 41 is the pOLY Si fuse, and 42 is the contact. When a high voltage is applied to both ends of the 4o AL wiring, a large current flows through the PoLY 81 fuse in 41, and the fuse melts. do.

[Problem to be solved by the invention]

This conventional fuse is the most common type, but as mentioned above, the material of the fuse is a metal that easily sublimates, so if a process that is not included in the standard process of Engineering C is required, or if the metal is used within the standard process. (POLY si)
There are two possible cases using 5. However, if a special metal is used here, the number of process steps increases and the wafer cost is increased, making it extremely unsuitable for fuses of only a few bits. C again! When using POLY Si in fuses such as MO8 IO, if covered with aVD, POLY Si will not melt ((
Normally, the OVD is used as an oven above the POLY Si in the fuse part. In this case, there is no problem when cutting the fuse during wafer inspection, but after mold mounting, the mold material blocks the aVD oven in the fuse section and the PO
LY Si no longer fuses. As described above, the conventional technology is not optimal for products that have a small number of bits and are programmed after being molded.

The present invention is intended to solve these problems, and provides a fuse that is reliable, inexpensive, and reliably functions as a fuse without requiring any special steps in the standard process. It is something.

[Means to solve the problem]

The semiconductor device of the present invention has a first wiring metal and a second wiring metal, and the first wiring metal and the second wiring metal are connected to each other through contacts with the first wiring metal and the second wiring metal. The central part of the resistor is thinner than the low resistance part connected by the respective contacts of the first wiring metal and the second wiring metal, and the thin part is the low resistance part of the contact part. It is characterized by an acute angle with the part.

〔Example〕

An embodiment of the present invention is shown in FIG. FIG. 1 shows the structure of the fuse, with 10 representing an AL for wiring, 11 a high resistance polysilicon, and 12 a contact between the polysilicon and the AL. Further, 13 is a low resistance POLYSi connected to AL through a contact. The angle between 11 and 12 is 14.15, which is an acute angle. POLYS
The fusing characteristics of i are greatly influenced by the following factors. One is the surface area per calorific value, one is the cross-sectional area of the part where the current flows, 1
One is the concentration of the electric field. In other words, in order to achieve the most efficient melting, it is necessary to have a large amount of heat generation (small surface area) and a small cross-sectional area. In normal processes, the sheet resistance of POLY Si is process-specific, and the width of POLY Si is limited by the design rules of that process.
It is necessary to increase the length of Si, but the surface area will increase. As described above, it is difficult to obtain optimal fusing characteristics with a normal structure. The present invention changes the shape of the fuse and concentrates the electric field to intensively increase the amount of heat generated in that area, thereby improving the fusing characteristics. A at the fuse of POLY Si
If the angle formed by the low-resistance portion J, 5 connected to the L wiring by a contact and the thin high-resistance portion 11 becomes an acute angle, the electric field will be extremely concentrated in that portion 1415, and the amount of heat generated will also be concentrated. Therefore, there are various shapes of the POLY Si resistor which are particularly susceptible to melting at that point, and Fig. 2 shows another embodiment of the present invention.This embodiment is also exactly the same as the explanation in Fig. 1. This is done by bending part 11 to form an acute angle part 16, which adds the possibility of fusing at this part and improving the fusing characteristics overall.In this way, the fusing part The energy required for fusing can be reduced by making it easier to cause this in certain areas.

〔Effect of the invention〕

In this way, if the fuse of the present invention is used, there is no need to add any new special process steps, so it is possible to
Even a t fuse has sufficient cost performance and can be made at a very low cost. Furthermore, the area weight is comparable to that of special fuse metals, and it can be easily applied to large-sized and ordinary fuse arrays. Furthermore, as for programming characteristics, more reliable writing characteristics can be realized compared to ordinary POLY Si fuses. Furthermore, since the writing characteristic is based on very low energy fusing, it does not have a destructive effect on surrounding CVD, AL, diffusion, etc., and is very beneficial to the reliability of the process.

As described above, by using the present invention, it is possible to provide a heater which can be simplified and which is very good in terms of cost and characteristics.

12... Contact 15... Low resistance part of POLY Si 14115.16... Acute angle forming part 40 of POLY Si...・・Al for wiring 41・・・・・・・POLY Si resistor 42・
········contact

[Brief explanation of drawings]

FIG. 1 is a diagram showing a fuse structure in an embodiment of the present invention. FIG. 2 is a diagram showing a fuse structure in an embodiment of the present invention. FIG. 6 is a diagram showing a conventional example. 10・・・・・・AL for wiring 11・・・・・・・・・POLY Si high resistance applicant Seiko Epson Corporation

Claims (1)

[Claims] It has a first wiring metal and a second wiring metal, and a resistor that connects the first wiring metal and the second wiring metal through a contact with the first wiring metal and the second wiring metal. and the center portion of the resistor is thinner than the low resistance portions connected by the respective contacts of the first wiring metal and the second wiring metal, and the thinner portion forms an acute angle with the low resistance portion of the contact portion. A semiconductor device characterized by: