SEMICONDUCTOR INTEGRATED CIRCUIT
The present invention aims at offering the semiconductor integrated circuit which can perform reliable relief processing using an electric fuse. The present invention is provided with a fuse wiring, a first electrode pad, a second electrode pad, a pollution-control layer, and a first via hole wiring and a second via hole wiring. And a fuse wiring is cut by passing beyond a predetermined current value. A first electrode pad is connected to one side of a fuse wiring. A second electrode pad is connected to the other of a fuse wiring. A pollution-control layer is formed in the upper layer and the lower layer of a fuse wiring via an insulating layer. It is formed via an insulating layer to the side surface of a fuse wiring, it connects with a pollution-control layer, and the first via hole wiring of a pair surrounds a fuse wiring. To a fuse wiring, the second via hole wiring of a pair is formed in the outside of a first via hole wiring so that a first via hole wiring may be surrounded.
The present application claims priority from Japanese patent application No. 2006-219370 filed on Aug. 11, 2006, and No. 2007-30263 filed on Feb. 9, 2007, the content of which is hereby incorporated by reference into this application.
1. Field of the Invention
The present invention is an invention concerning a semiconductor integrated circuit, and especially relates to the semiconductor integrated circuit provided with a fuse.
2. Description of the Background Art
By forming a fuse in a semiconductor integrated circuit, the fuse was cut, the value of resistance was adjusted and relief processing, such as transposing a defective element to a normal element, was performed. And generally the laser fuse cut by the laser beam irradiation from the outside was used as a fuse conventionally used for relief processing.
However, since laser irradiation was done and fuse cutting was done from the outside, the laser fuse cannot perform relief processing after a mold. Since memory space's doing realization of high-capacity in a memory or SOC (System On a Chip) and SIP (System in Package) are used, in order to improve the yield at an early stage, relief processing is needed after a mold. However, since the laser irradiation from the outside cut with the laser fuse, relief processing was able to be performed only on the bare wafer.
The electric fuse which sends current and is cut and which is relievable even if it is on site or after molding, naturally on wafer is used for the semiconductor integrated circuit. Since it cut by doing laser irradiation from the outside, the trimming dedicated device and the relief processing step were required of the laser fuse. However, since it can trim immediately after a test using a circuit tester with an electric fuse, it is newly unnecessary in trimming equipment or a relief processing step. This electric fuse is described to Patent Reference 1 or Patent Reference 2.
[Patent Reference 1] Japanese Unexamined Patent Publication No. 2005-39220
[Patent Reference 2] Japanese Unexamined Patent Publication No. 2005-57186
SUMMARY OF THE INVENTIONWhen using an electric fuse for a semiconductor integrated circuit, it is necessary to minimize the area of a relieving circuit including an electric fuse as much as possible. In order to generate current required for cutting of an electric fuse especially, a power supply circuit is required. In order to minimize the area of this power supply circuit as much as possible, it is necessary to minimize current required for cutting.
When an electric fuse is cut, there is a problem of a crack occurring from a cut section, or the wiring material of a cut section dispersing, polluting a periphery, and reducing the reliability of a semiconductor integrated circuit.
Then, the present invention aims at offering the semiconductor integrated circuit which can perform reliable relief processing using an electric fuse.
The solving means concerning the present invention comprises a fuse wiring cut by passing beyond a predetermined current value, a first electrode pad connected to one side of the fuse wiring, a second electrode pad connected to the other of the fuse wiring, a pollution-control layer formed in an upper layer and a lower layer of the fuse wiring via an insulating layer, a first via hole wiring of a pair which is formed via the insulating layer to a side surface of the fuse wiring, connects with the pollution-control layer, and surrounds the fuse wiring, and a second via hole wiring of a pair formed in an outside of the first via hole wiring to the fuse wiring so that the first via hole wiring may be surrounded.
A semiconductor integrated circuit described in the present invention is provided with the first via hole wiring of the pair which connects with a pollution-control layer and surrounds a fuse wiring, and the second via hole wiring of a pair formed so that a first via hole wiring may be surrounded. When an electric fuse is cut, it prevents the wiring material of a cut section dispersing and polluting a periphery, and has the effect of improving the reliability of a semiconductor integrated circuit. In a semiconductor integrated circuit described in the present invention, since the influence of the up-and-down layer on the fuse wiring at the time of fuse cutting can be suppressed by arranging a pollution-control layer, the up-and-down layer concerned can be wired and reduction of chip size is attained.
First, the usage use of the electric fuse used for a semiconductor integrated circuit is explained using
In
The wiring blowout type electricity fuse is used in the semiconductor integrated circuit concerning this embodiment. Generally polysilicon was used for this electric fuse as a fuse wiring material until now. Since the frequency in use of metal wiring will increase from now on, Cu, Al, Ti, Ta, etc. come to be used as a fuse wiring material. So, this embodiment explains the electric fuse which used Cu as a fuse wiring material. Even if it uses fuse wiring materials other than Cu, an effect equivalent to the effect described below can be acquired.
The perspective view of the electric fuse related to this embodiment at
A required thing is designing the structure of the blown-out type electricity fuse which is 100% of a relief rate, and makes cutting current the minimum from a viewpoint of the structural design of a fuse. However, fuse wirings 1 which can be stably cut with the minimum cutting current differ according to fuse width, fuse thickness, material, etc. In fuse wiring 1 shown in
With the electric fuse concerning this embodiment, in order to always generate a cutting part in the central part of fuse wiring 1, the number of plugs 4 for feeding power and the number of plugs 5 for GND supply are made into the same number. Each cross section of plug 4 for feeding power and plug 5 for GND supply is the same. Hereby, when applying current and cutting at an electric fuse, the heat of fuse wiring 1 generated in application of current escapes from plug 4 for feeding power, and plug 5 for GND supply uniformly, and it can cut in the mostly central part of fuse wiring 1.
However, the number of plugs 4 for feeding power and the number of plugs 5 for GND supply are not necessarily restricted to the same number. When the total of a contact cross section with electrode pad 2 for feeding power of a plurality of plugs 4 for feeding power is the same as the total of a contact cross section with electrode pad 3 for GND supply of a plurality of plugs 5 for GND supply, it is good.
The electric fuse concerning this embodiment is formed in a fine layer in the semiconductor integrated circuit with which a global layer is about 1000 nm, a semi global layer is about 350 nm, and a fine layer is about 200 nm. In this embodiment, although the fine layer is about 200 nm, generally the layer about 300 nm—about 100 nm is called fine layer. With the cross-sectional view shown in
In
In order to cut fuse wiring 1, it is necessary to change the material of fuse wiring 1 from a solid to a liquid. That is, it is necessary to send current through fuse wiring 1 and to raise the temperature of fuse wiring 1 self at the lowest to the melting point (for a melting point to be about 1100° C., when material is Cu) of the material concerned.
Next, the SEM (Scanning Electron Microscope) photography of an electric fuse is shown in
The simulation of the heat generated in fuse wiring 1 is done by the case where the number of plug 4 for feeding power and the number of plug 5 for GND supply are made into the same number, and the case where it is made a different number. As a result, when the number of plug 4 for feeding power and the number of plug 5 for GND supply are made into the same number, compared with the case where it is made a different number, the portion which reaches beyond a melting point becomes short within fuse wiring 1. And it turned out that the portion more than melting point temperature concentrates on the central part of fuse wiring 1.
In the semiconductor integrated circuit concerning this embodiment, as shown in the SEM photography of
The SEM photography for a cut section of fuse wiring 1 is shown in
Cu crack shown in
So, with the electric fuse concerning this embodiment, crack expansion prevention layer 10 shown in
With the electric fuse concerning this embodiment, pollution-control layer 11, and via hole wirings 12 and 13 shown in
With the electric fuse concerning this embodiment, as shown in
With the electric fuse concerning this embodiment, one end of via hole wiring 12 approaches electrode pad 2 for feeding power, and the other end of via hole wiring 13 is close to electrode pad 3 for GND supply. Here, that the one end of via hole wiring 12 approaches electrode pad 2 for feeding power means the state where they are approaching to the degree which can prevent dispersed Cu, although an insulating film exists between via hole wiring 12 and electrode pad 2 for feeding power. It is also the same that the other end of via hole wiring 13 approaches electrode pad 3 for GND supply.
Unless it passes through the portion pinched with via hole wiring 12 and via hole wiring 13 passing through between via hole wiring 12 and electrode pads 3 for GND supply, it becomes impossible hereby, for Cu which dispersed by cutting of fuse wiring 1 to come out of an electric fuse. That is, by making via hole wiring 12 and via hole wiring 13 into alternate structure, as shown in
With the electric fuse concerning this embodiment, via hole wiring 12 and via hole wiring 13 presupposed that alternate structure like
Next, crack expansion prevention layer 10 has a structure discontinuous to the wiring direction of fuse wiring 1, as shown in
On the other hand, the case of structure with crack expansion prevention layer 10 discontinuous to the wiring direction of fuse wiring 1 is shown in
Next, as the electric fuse concerning this embodiment is shown in
The distance of crack expansion prevention layer 10, pollution-control layer 11 and via hole wiring 12, and fuse wiring 1 is explained concretely.
And the result of having measured the fuse current before and after cutting processing (processing which applies the current beyond a predetermined current value for cutting) to the electric fuse of the structure shown in
The result shown in
Similarly, the result shown in
On the other hand, the result shown in
When pollution-control layer 11 approaches fuse wiring 1 too much from the result shown in
When it thinks from a viewpoint which misses the heat generated at the time of the cutting processing of fuse wiring 1, it is necessary to also keep the same the distance of crack expansion prevention layer 10, via hole wiring 12, and fuse wiring 1 at at least 400 nm. Hereby, the electric fuse concerning this embodiment can avoid decline in a relief rate.
Since one layer is about 200 nm when forming the wiring layer shown in
It was the structure of having formed crack expansion prevention layer 10, and pollution-control layer 11, and via hole wirings 12 and 13 with the electric fuse concerning this embodiment as shown in
In Embodiment 2, as shown in
As fuse wiring 1 is shown in
On the other hand, with the electric fuse concerning this embodiment, as shown in
Cut section 21 shown in
Cut section 21 shown in
Claims
1. A semiconductor integrated circuit, comprising:
- a fuse wiring cut by passing beyond a predetermined current value;
- a first electrode pad connected to one side of the fuse wiring;
- a second electrode pad connected to the other side of the fuse wiring;
- a pollution-control layer formed in an upper layer and a lower layer of the fuse wiring via an insulating layer;
- a first via hole wiring of a pair which is formed via the insulating layer to a side surface of the fuse wiring, connects with the pollution-control layer, and surrounds the fuse wiring; and
- a second via hole wiring of a pair formed in an outside of the first via hole wiring to the fuse wiring so that the first via hole wiring may be surrounded.
2. A semiconductor integrated circuit according to claim 1, wherein one end of the first via hole wiring is close to the first electrode pad, and the other end of the second via hole wiring is close to the second electrode pad.
3. A semiconductor integrated circuit according to claim 1, wherein 400 nm or more of distance of the pollution-control layer and the first via hole wiring, and the fuse wiring is secured.
4. A semiconductor integrated circuit according to claim 1, wherein between the pollution-control layer and the fuse wiring, two or more layers of fine layers are formed at least.
5. A semiconductor integrated circuit according to claim 1, further comprising:
- a crack expansion prevention layer discontinuous in a wiring direction of the fuse wiring, the crack expansion prevention layer formed in an upper layer and a lower layer of the fuse wiring via the insulating layer between the fuse wiring and the pollution-control layer.
6. A semiconductor integrated circuit, comprising:
- a fuse wiring cut by passing beyond a predetermined current value;
- a first electrode pad connected to one side of the fuse wiring;
- a second electrode pad connected to the other side of the fuse wiring; and
- a crack expansion prevention layer discontinuous in a wiring direction of the fuse wiring, the crack expansion prevention layer formed in an upper layer and a lower layer of the fuse wiring via an insulating layer.
7. A semiconductor integrated circuit according to claim 6, wherein 400 nm or more of distance of the crack expansion prevention layer and the fuse wiring is secured.
8. A semiconductor integrated circuit according to claim 6, wherein between the crack expansion prevention layer and the fuse wiring, two or more layers of fine layers are formed at least.
9. A semiconductor integrated circuit according to claim 1, further comprising:
- a plurality of first plugs electrically connected with the first electrode pad; and
- a plurality of second plugs electrically connected with the second electrode pad;
- wherein
- a total of a contact cross section with the first electrode pad of the first plugs is the same as a total of a contact cross section with the second electrode pad of the second plugs.
10. A semiconductor integrated circuit according to claim 1, further comprising:
- a plurality of first plugs electrically connected with the first electrode pad; and
- a plurality of second plugs electrically connected with the second electrode pad;
- wherein
- a cross section of the second plug is the same as a cross section of the first plug, and a number of the second plug is the same as a number of the first plug.
11. A semiconductor integrated circuit according to claim 1, wherein the fuse wiring is formed in a fine layer.
12. A semiconductor integrated circuit according to claim 1, wherein the pollution-control layer has a portion electrically cut at least one place in a position corresponding to a fuse wiring which functions as an electric fuse.
Type: Application
Filed: Aug 9, 2007
Publication Date: Oct 2, 2008
Inventors: Toshiaki Yonezu (Tokyo), Takeshi Iwamoto (Tokyo), Shigeki Obayashi (Tokyo), Masashi Arakawa (Tokyo), Kazushi Kono (Tokyo)
Application Number: 11/836,609
International Classification: H01L 23/48 (20060101);