JPH04363049A - Semiconductor device - Google Patents

Abstract

PURPOSE:To provide a semiconductor device wherein even a fuse element composed especially of a thin film can be blown surely even when the alignment of a laser beam is displaced with reference to the fuse element. CONSTITUTION:A semiconductor device is composed of a main circuit and a redundant circuit which protects it. A semiconductor substrate 10 is provided with an interconnection layer which constitutes an interconnection pattern for the main circuit. A fuse element 30 is formed in the redundant circuit by utilizing the pattern in one part of the interconnection layer; the fuse element 30 can be blown by using a laser beam 40. The fuse element 30 is constituted of fuse interconnection layers 32 which have been formed in a plurality of rows by keeping an interval in its interconnection-width direction; the fuse interconnection layers 32 in the individual rows are connected in series. Even when the alignment of the laser beam 40 is displaced, the fuse interconnection layers 32 in any row can be blown surely.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device equipped with a fuse element constituting a part of a redundant circuit. The present invention relates to a semiconductor device that can reliably melt and cut.

0002

2. Description of the Related Art Semiconductor devices are known that include, in addition to a main circuit such as a memory circuit, a redundant circuit for protecting the main circuit. This redundant circuit consists of one part of the semiconductor device.
When a defective element occurs in a chip, the fuse element at the corresponding address is fused with a laser beam, thereby replacing the defective element with a normal element.

FIG. 13 shows a fuse element of a conventional semiconductor device.
This will be explained with reference to (A) and (B).

In each figure, a silicon oxide film 102 is formed on a silicon substrate 100, and a fuse element 104 made of a polycrystalline silicon film is further formed on the silicon oxide film 102 using a partial pattern of a wiring layer. . Both ends of the fuse element 104 covered with the silicon oxide film 106 are
Aluminum wiring 11 via contact hole 108
Connected to 0. Then, the fuse element 104 is blown by the laser beam 11, as shown in FIG. 13(A).
The fuse element 104 is heated by irradiating the fuse element 104 with 2.

[0005]

Problems to be Solved by the Invention One of the causes of erroneous blowing of the fuse element 104 is misalignment of the laser irradiation device. Generally, alignment devices used in laser irradiation devices are not as accurate as steppers in exposure devices, and it is said that alignment accuracy is about 1 μm for fuse element 104 having a width of 2 μm.

[0006] The fuse element 1 is
As an essential condition to be able to fuse the fuse element 10
All of the wiring widths of No. 4 are within the beam diameter. However, if even a part of the wiring width of the fuse element 104 deviates from within the beam diameter due to misalignment, the fuse element 104 can no longer be opened, resulting in a blowout error.

A blowing error also occurs when the entire wiring width of the fuse element 104 is within the beam diameter. this is,
This is caused by the energy distribution of the laser beam. This energy distribution is as shown in FIG. 11, and as the distance x from the beam center increases, the energy density of the laser beam decreases. Therefore, the more the center of the laser beam deviates from the center of the fuse element 104 due to misalignment, the less energy contributes to blowing, and the more blowing errors occur.

The first problem that the inventor of the present invention has focused on is to reliably eliminate blowing errors of fuse elements caused by misalignment.

It is thought that such fusing errors will increase more and more as the miniaturization of semiconductor devices progresses rapidly. This is because as semiconductor devices become smaller, the thickness of the fuse element 104 has to be reduced, and the thinner the film, the less energy is absorbed.

If a misalignment of the laser beam 112 occurs with respect to the thin film fuse element 104, the factors that prevent the fuse element 104 from blowing will overlap, and the number of blowing errors will further increase. The second point that the inventor focused on
The challenge is to reliably blow out fuse elements, which tend to become thinner.

[0011] The following publications disclose techniques for blowing fuse elements, but no countermeasures are taken against blowing errors caused by misalignment and thinning of the fuse element.

Japanese Unexamined Patent Publication No. 61-51966 discloses a technique in which a shock absorbing layer made of a polycrystalline silicon film is provided below a fuse element. In this way, even if the output of the laser beam is increased and the fuse element 104, which tends to become thinner, is blown, an adverse effect on the silicon substrate can be prevented. However, if misalignment of the laser irradiation device occurs, it is impossible to reliably blow out the fuse element. The shock absorbing layer made of polycrystalline silicon film only absorbs the beam transmitted through the fuse element.

Japanese Patent Application Laid-Open No. 58-640610 discloses a technique for providing a highly light-absorbing coating above a fuse element. In addition, Japanese Patent Application Laid-Open No. 60-17625,
A technique is disclosed in which a window is provided above the fuse element to expose the fuse element. Both of these two techniques can only ensure a relatively high amount of incident energy only when the fuse element is within the beam diameter, and do not provide a measure against misalignment.

[0014] Japanese Patent Application Laid-open No. 58-207665 discloses that V
A technique for forming a fuse element along a character-shaped groove is disclosed. According to this technique, the fuse element melts and flows along the V-shaped groove when irradiated with the laser beam, so it can be blown out with relatively low power. However, no countermeasures have been taken for the case where the laser beam is misaligned in the width direction of the fuse element.

An object of the present invention is to provide a semiconductor device that can reliably blow out a fuse element even when a laser irradiation device is misaligned.

Another object of the present invention is to provide a semiconductor that can reliably blow out a fuse element without significantly increasing the output of a laser beam, even if the film thickness of the fuse element becomes thinner due to miniaturization of the element. The goal is to provide equipment.

Another object of the present invention is to make it possible to reliably blow out the fuse element even when the two adverse conditions of thinning the fuse element and misalignment of the laser irradiation device combine. The purpose of the present invention is to provide semiconductor devices.

[0018]

[Means for Solving the Problems] A semiconductor device according to a first invention for achieving the above object includes a wiring layer formed on a semiconductor substrate, and a pattern formed as a part of the wiring layer, which is formed by an energy beam. a fuse element;
The fuse element is characterized in that it is composed of fuse wiring layers provided in a plurality of columns at intervals in the wiring width direction, and that the fuse wiring layers in each column are connected in series.

A semiconductor device according to a second aspect of the invention includes a high melting point metal film formed on a semiconductor substrate, a wiring layer formed on the high melting point metal film via an interlayer insulating layer, and a part of the wiring layer. and a fuse element that is formed as a pattern and can be blown by an energy beam, and a part of the high melting point metal film is formed at a lower layer position facing the fuse element.

[0020] A third invention includes a high melting point metal film formed on a semiconductor substrate, a wiring layer formed on the high melting point metal film via an interlayer insulating layer, and a pattern formed as a part of the wiring layer. and a fuse element that can be blown by an energy beam, and the fuse element is composed of fuse wiring layers provided in multiple rows at intervals in the wiring width direction, and the fuse element in each row is The wiring layers are connected in series, and a part of the refractory metal film is formed at a lower layer position facing the fuse wiring layer of each column of the fuse elements.

[0021] A semiconductor device according to a fourth aspect of the present invention includes a first wiring layer formed on a semiconductor substrate, and an interlayer insulating layer formed on the upper layer of the first wiring layer, and wherein the first wiring a second wiring layer thinner than the first wiring layer; a first fuse element formed as a pattern of a part of the first wiring layer; and a first fuse element formed as a pattern of a part of the second wiring layer. The second fuse element is formed in an upper layer position facing the fuse element, and is connected in series to the first fuse element through a contact hole.

[0022]

[Operation] Misalignment of the laser irradiation device occurs in all directions, but especially when the laser beam deviates from the wiring width of the fuse element, it is no longer possible to blow out the fuse element. In the first invention, since the fuse wiring layers are provided in multiple rows at intervals in the wiring width direction, even if the laser beam is shifted particularly in the wiring width direction, any one of the fuse wiring layers is always connected. It can be positioned within the beam diameter of the laser beam, ensuring reliable fusing. And the fuse wiring layer of each column is
Since they are connected in series, it is possible to always open the fuse element by simply blowing out one row of fuse wiring layers.

A plurality of series-connected fuse wiring layer patterns can be easily formed using a mask pattern used in a photolithography process, and the number of manufacturing steps is not increased.

[0024] In general, the area for arranging the fuse element can be secured relatively wide even if the main circuit area of the semiconductor device is miniaturized, so the multi-column pattern does not hinder the miniaturization of the semiconductor device.

In the second invention, when a high melting point metal film is used as a wiring layer on a semiconductor substrate, by forming this high melting point metal film at a lower layer position facing the fuse element, the fuse element The laser beam that has passed through can be reflected and used as fusing energy for the fuse element. In particular, if the fuse element is a thin film of 1000 angstroms or less, energy absorption is low and transmitted energy is high, so by reflecting this and using it as part of the fusing energy, it is possible to ensure the reliable fusing of the thin fuse element. becomes possible. Moreover, even if the beam center deviates from the center of the fuse element due to misalignment and the energy directly incident on the fuse element decreases, the reflected energy can reliably blow out the fuse element. Such a high melting point metal film is made of, for example, S
RAM (static random access memory)
It is used as a gate electrode or a wiring layer for a Vss power supply. Therefore, the high melting point metal film formed in the lower layer position facing the fuse element can be realized simply by changing the mask pattern in the photolithography process. Therefore, even if the fuse element becomes thinner, the number of manufacturing steps will not be increased just to manufacture a redundant circuit, and the thinner fuse element can be reliably fused without increasing the product cost.

The third invention is a combination of the first invention and the second invention, and even when a large misalignment of the laser irradiation device occurs, at least one of the plurality of rows
It is possible to reliably blow out two fuse wiring layers. Furthermore, a high melting point metal film that can reflect the energy beam that has passed through the thinned fuse wiring layer is always formed in the lower layer facing the fuse wiring layer, increasing the amount of energy absorbed by the fuse wiring layer. Thus, reliable fusing can be achieved.

As semiconductor devices become smaller, the energy absorption of the thinner second fuse element deteriorates. In particular, if a beam with low energy density is irradiated due to misalignment, there is a possibility that the second fuse element cannot be blown out. Therefore, in the fourth invention, a first fuse element that is thicker than the second fuse element is arranged in this lower layer,
The beam energy transmitted through the second fuse element blows out the first fuse element, which has a high energy absorption property. Since the first and second fuse elements are connected in series, the fuse element can be reliably opened by blowing one of them.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) The structure of a redundant circuit portion of a semiconductor device to which the apparatus of Embodiment 1 relates will be explained in the order of manufacturing steps with reference to FIG.

First, a P-type or N-type silicon substrate 10 is prepared.
is oxidized in a wet atmosphere at 1100° C. to form a silicon oxide film 16 with a thickness of about 8000 angstroms. Next, a polycrystalline silicon film serving as a wiring layer is formed to a thickness of about 1000 angstroms by CVD. Next, after forming a pattern for etching by photolithography, unnecessary portions of the polycrystalline silicon film are removed by plasma etching. Then, a fuse element 30 made of a polycrystalline silicon film is formed. Note that the fuse element 30 may be formed of a single crystal silicon film or an amorphous silicon film instead of the polycrystalline silicon film.

Here, the fuse element 30 is formed by meandering one line of wiring layer. As a result, the fuse element 30 is composed of a plurality of rows of fuse wiring layers 32 provided at intervals in the wiring width direction, and the fuse wiring layers 32 of each row are connected in series. In this way, the pattern of the fuse element 30 as shown in FIG.
As shown in (A), two or more fuse wiring layers 32 are formed within the beam diameter of the laser beam 40.

Next, the silicon oxide film 18 is formed by the CVD method.
5000 angstroms. Thereafter, an etching pattern for contact holes 20 is formed by a photolithography process, and dry etching is performed to form contact holes 20. Next, approximately 1 μm of aluminum containing 5% silicon was formed by sputtering.
After forming an etching pattern by a photolithography process, dry etching is performed to form aluminum wiring 22.

Here, if a defect occurs in the chip constituting the memory circuit, which is the main circuit, due to adhesion of dust, for example, the fuse element 30 corresponding to the address is blown by the laser beam 40 to repair it.

At this time, even if the fuse element 30 and the laser beam 40 are deviated in any direction due to misalignment, the fuse element 20 can be reliably blown out. That is, the fuse element 30 is composed of a plurality of rows of fuse wiring layers 32 formed in a meandering manner and arranged at intervals in the wiring width direction as shown in FIG. ), any one row of fuse wiring layers 32 can always be present. Therefore,
Even if there is a large misalignment that deviates from the wiring width of one row of fuse wiring layers 32, one of the fuse wiring layers 32 in the plurality of series-connected rows is reliably blown and the fuse element 30 is reliably opened. can be done.

Here, as shown in FIG. 2, the arrangement condition for the fuse wiring layer 32 is such that the effective beam diameter that contributes to the laser beam 40 blowing out the fuse wiring layer 30 is (
D), the width of each fuse wiring layer 32 is (W), and the center pitch of two adjacent fuse wiring layers 32 is (P), then D>P+W. In this way, even if misalignment occurs in parallel to the width direction of the fuse wiring layer 32, one fuse wiring layer 32 can always be blown out by the laser beam 40. The energy distribution of the laser beam 40 is as shown in FIG. 11, and the effective beam diameter (D) is the energy (E') sufficient to blow out the fuse wiring layer 32, for example, the energy (E') of approximately 1 μJ. is the beam diameter with .

More preferably, the condition is set as D≧2P+W. In this way, one row of fuse wiring layers 32 is placed at the beam center position of the effective beam (D).
is more likely to exist. Therefore, since the center area of the beam having the highest energy can be used for blowing out, the thinned fuse wiring layer 32 can be definitely blown out.

(Example 2) In a semiconductor device according to Example 2, two wiring layers are formed at different positions in the thickness direction with an interlayer insulating layer interposed therebetween, and one fuse element is connected to two wiring layers in different layers. It is formed using layers.

In FIG. 3, an element isolation insulating layer 12 and a gate oxide film 14 are sequentially formed on a silicon substrate 10, and a silicon oxide film 16 is formed thereon. On the silicon oxide film 16, a polycrystalline silicon film with a thickness of about 1000 angstroms is formed as a first wiring layer, and after forming an etching pattern by photolithography, for example, two lower fuse wiring layers 52, 52 are formed by plasma etching. formed in parallel. On the lower fuse wiring layers 52, 52, a second layer silicon oxide film 18 as an interlayer insulating layer is provided with contact holes 20 and
26, and a polycrystalline silicon film having a thickness of about 1000 angstroms is formed thereon as a second wiring layer. Then, by the same photolithography process and etching process, a
An upper fuse wiring layer 54 is formed. This upper fuse layer 54 is connected to the lower fuse wiring layer 52 using the contact hole 26. After that, a silicon oxide film 24 is further formed thereon, and finally an aluminum wiring 2
Do step 2. Aluminum wiring 22 is contact hole 2
0 is used to connect to the lower fuse layer 52.

Here, the two lower fuse wiring layers 52,
52 and the upper fuse wiring layer 54 formed therebetween are connected in series to the aluminum wiring 22 using the contact hole 26. In this way, the fuse element 50 has a plurality of rows of fuse wiring layers 52, 52, 54 formed of different layers at intervals in the width direction of the fuse wiring layers, and each row is connected in series. Connected.

As a result, the fuse element 50 according to the second embodiment also receives the laser beam 4 as in the first embodiment.
Two or more fuse wiring layers can exist within an effective beam diameter D of 0.

(Embodiment 3) The structure of a semiconductor device according to Embodiment 3 will be explained with reference to FIG. 4.

The semiconductor device according to the third embodiment uses a refractory metal film as the first wiring layer, and a second wiring layer formed on top of this with an interlayer insulating layer interposed therebetween. This is a semiconductor device containing crystalline silicon.

In this embodiment, the second layer of polycrystalline silicon is used to form one line of fuse elements 60 through photolithography and etching steps. Then, a high melting point metal film, for example, a tungsten film 62, which is a first wiring layer, is applied to the fuse element 6.
Pattern formation in a photolithography process and subsequent etching process are performed so that the pattern is formed in a lower layer position facing 0. In this embodiment, the thickness of the tungsten film 62 is 2000 angstroms, and the thickness of the fuse element 60 is 800 angstroms. Further, the tungsten film 62 is formed over a wider area than the lower layer position facing the fuse element 60. This is to ensure that even if the wiring pattern is shifted in the width direction when forming the fuse element 60, the tungsten film 62 is always present underneath.

In FIGS. 4A and 4B, when the laser beam 40 is irradiated from above, a portion of it is absorbed by the fuse element 60 made of a polycrystalline silicon film. According to the inventor's experiments, a fuse 60 made of a polycrystalline silicon film
It has been found that when the film thickness is less than 1000 angstroms, the absorption rate of laser light becomes poor and most of the laser light is transmitted. As a result, the fuse 60 may not generate enough heat to blow the fuse.

Here, the energy E absorbed by the fuse element 60 is as follows.

E=Φ[1-exp(-α×t)]Φ: Incident power α: Absorption coefficient t of the fuse element: Film thickness of the fuse element The absorption coefficient α of the polycrystalline silicon constituting the fuse element is YLF laser (wavelength = 1047n) as a light source
m) or YAG laser (wavelength = 1056 nm), the absorption coefficient at that wavelength is approximately α = 3 × 10 (1/cm
).

Therefore, when the film thickness of the fuse element is 2000 angstroms as in the conventional case, the absorbed energy E
1 is E1 = 0.006Φ, whereas when the film thickness t = 1000 angstroms, the absorbed energy E2 is E2 = 0.0
03Φ, and it can be seen that the absorption rate decreases considerably.

Therefore, as in this embodiment, the fuse element 6
When a tungsten film 62 is provided below the fuse element 60, the laser beam 40 transmitted through the fuse element 60 is reflected on the tungsten film 62 and is absorbed again by the fuse element 60 made of a polycrystalline silicon film. Therefore, the high melting point metal film 6
If most of the light incident on 2 is reflected, within the fuse element 60, approximately 2
Absorption of twice as much (directly incident + reflected) laser beam will occur. Therefore, the amount of heat generated by the fuse element 60 also approximately doubles, so that even if the film thickness of the fuse element 60 is made thinner, the defect that the fuse cannot blow is eliminated.

Considering that the laser beam incident energy distribution is as shown in FIG. Due to misalignment of the irradiation device, there may still be cases where the fuse cannot be blown. In this embodiment, the width of the fuse element 60 made of a polycrystalline silicon film is (W), the beam diameter of the laser beam is (φ), the width of the high melting point metal film is L, and W<φ
<It is set to L. Therefore, even if the laser beam 40 is slightly deviated due to misalignment, the energy absorption of the fuse element 60 will be approximately doubled.
There is no longer a possibility that the fuse element 60 cannot be blown.

The above operation will be explained by comparing FIGS. 12 and 11. FIG. 12 is a diagram of the incident + reflected energy density of the laser beam incident on the fuse element 60 in this embodiment.

In FIGS. 11 and 12, x is the distance from the laser beam center, φ is the laser beam diameter, and EF
is the incident energy density of the laser beam, EFR is the incident + reflected energy density of the laser beam assuming that the absorption rate of the laser beam is 10%, E' is the energy density required to blow the fuse, and W is the polycrystalline silicon. The fuse width due to the membrane, MG, is the allowable beam for blowing the fuse, and the alignment margin of the fuse element.

In FIGS. 11 and 12, the fuse width (W) is 1 μm, and the beam diameter (φ) of the laser beam is
is 5 μm. In the conventional example shown in FIG. 13, the alignment margin (MG) for cutting the fuse is small as shown in FIG. 11, and is only 0.6 μm on one side. On the other hand, in this embodiment shown in FIG. 4, the alignment margin (MG) is
The width becomes as wide as 1.6 μm can be secured.

In this embodiment shown in FIG. 4, the tungsten film 62 is formed directly on the silicon substrate 10, but the tungsten film 62 is formed after forming a silicon oxide film on the silicon substrate 10 by thermal oxidation or CVD. You may.

Further, as the high melting point metal film functioning as a reflective layer, the tungsten film 62 was used in this embodiment, but any metal having a sufficiently higher melting point than the fuse element 60 on the upper layer may be used, preferably a metal with a melting point higher than that of the fuse element 60. Metals with temperatures above 1400°C include molybdenum, titanium, platinum, nickel,
Cobalt, tantalum films, etc. may also be used. or,
As the high melting point metal film, a high melting point metal silicide film which is a silicon compound of these single high melting point metals may be used. The above single metal film or silicide film may preferably be formed to a thickness of 500 to 3000 angstroms as a reflective layer. Furthermore, as a high melting point metal film, 5
A refractory metal polycide film may be used in which the above single refractory metal film is formed to a thickness of 500 to 2000 angstroms on polycrystalline silicon of 00 to 2000 angstroms. These materials can be similarly applied to the high melting point metal films of each of the following examples.

(Embodiment 4) A semiconductor device according to this embodiment 4 has a fuse element 7 arranged in a planar manner as shown in FIG.
Consists of 0. This fuse element 70 includes an upper fuse wiring layer 72 made of a polycrystalline silicon film, and
It is composed of a high melting point metal film, for example, a tungsten film 74, which is formed at a lower layer position opposite to this, and both are connected in series through a contact hole 26 at one end. Further, the other ends of the fuse wiring layer 72 and the tungsten film 74 are connected to the aluminum wirings 22 and 22 through contact holes 20, respectively, in areas drawn out to the left and right from the overlapping area of the two layers. That is, the wiring positions of the aluminum wirings 22, 22 with respect to both ends of the fuse element 70 are arranged in parallel on the same side of the fuse element 70. In this way, the fuse element 7 has a two-layer structure with an approximately T-shaped pattern.
It constitutes 0.

The cross-sectional structure of this fuse element 70 is shown in FIG.
As shown in (A) to (C). In this embodiment, the fuse wiring layer 72 is formed using a part of the third wiring layer which is the uppermost layer among the first to third wiring layers constituting the memory circuit which is the main circuit. However, a tungsten film 74 is formed using a part of the pattern of the second wiring layer.

According to this structure, even if the energy absorption of the laser beam 40 directly incident on the fuse wiring layer 72, which is a relatively thin film, is small, as in the third embodiment, the fuse wiring layer 72 can be Most of the transmitted laser beam 40 penetrates the underlying tungsten film 74.
This energy can also be used to blow out the fuse wiring layer 72.

(Embodiment 5) The planar arrangement of the semiconductor device according to this embodiment 5 is as shown in FIG.
Its cross-sectional structure is shown in FIGS. 7(A) to 7(C). That is, this fifth embodiment device also has the same features as the fourth embodiment device.
They are the same in that they have a tungsten film 74 in the lower layer opposite to the fuse wiring layer 72 that uses the third wiring layer, but the tungsten film 74 covers the first wiring layer of the memory circuit constituting the main circuit. A part of the pattern is formed to extend to a position below the fuse wiring layer 72.

In the case of the fifth embodiment, as in the third and fourth embodiments, the energy of the laser beam 40 that has passed through the relatively thin fuse wiring layer 72 is reflected by the tungsten film 74, thereby forming the fuse wiring. This can contribute to the fusing of the layer 72. However, the fuse wiring layer 72
and the tungsten film 74 as an interlayer insulating layer.
Since the silicon oxide films 16 and 18 are present, the fusing energy is consumed by the amount of energy absorbed there.

(Example 6) Similarly, the planar arrangement of the semiconductor device according to Example 6 is as shown in FIG. 5, and its cross-sectional structure is as shown in FIGS. 8(A) to 8(C). This is what I did. That is, the fuse wiring layer 72 is formed using a part of the pattern of the second layer wiring layer of the memory circuit constituting the main circuit. On the other hand, the tungsten film 74 is
It is formed using a pattern of a part of the first wiring layer of the memory circuit. Similar to each of the embodiments described above, the energy reflected by the tungsten film 74 can be used as the energy for blowing the fuse wiring layer 72.

(Embodiment 7) In a semiconductor device according to Embodiment 7, a fuse element 80 is composed of an upper fuse element 82 made of polycrystalline silicon and a lower fuse element 82 made of a high melting point metal film formed in a region facing the upper fuse element 82. It is composed of an element 86. Furthermore, the upper and lower layer fuse elements 82 and 86 are constructed of respective fuse wiring layers 84 and 88 provided in a plurality of rows at intervals in the wiring width direction. Then, upper layer and lower layer fuse elements 82, 86
One end of each is connected in phase using a contact hole 26, and the other end is connected to aluminum wirings 22, 22 using a contact hole 20, respectively.

According to this seventh embodiment, the upper layer fuse element 82 has a plurality of rows of fuse wiring layers 8 in the wiring width direction.
4, even if misalignment occurs, one fuse wiring layer 84 can always be present within the effective beam diameter D of the laser beam 40 and can be blown.

Moreover, since the fuse wiring layer 88 formed of a high-melting point metal film is always present in the lower layer position facing each of the plurality of rows of fuse wiring layers 84 constituting the upper layer fuse element 82, the fuse wiring layer 88 formed of a high melting point metal film is always present, so that the fuse wiring layer 88 is formed of a relatively thin film. Upper fuse wiring layer 8
Even if the laser beam 40 passes through the fuse wiring layer 88 in the lower layer, the energy that contributes to blowing out the fuse wiring layer 84 in the upper layer can be increased, and a reliable fuse element 80 can be generated. can achieve fusing.

As a modification of this seventh embodiment, the semiconductor substrate 1
In the case where three wiring layers are formed in the wiring layer 0, three types of combinations can be applied as in Examples 4 to 6.

In the fourth to seventh embodiments described above, the upper fuse wiring layers 72 and 84 and the lower fuse wiring layers 74 and 88 made of a high melting point metal film are connected in series, and both of them are connected in series. Although the fuse elements 70 and 80 were constructed, both ends of the upper fuse wiring layers 72 and 84 were connected to the aluminum wirings 22 and 22, and the lower refractory metal films 74 and
It is also possible to use 88 only as a reflective layer for laser beam 40.

Furthermore, when the lower refractory metal film is formed to be wider than the upper fuse wiring layer, it is preferable to form the surface of the refractory metal film into a concave lens shape. In this way, the laser beam that has passed through the upper fuse wiring layer and entered the high melting point metal film can be focused and reflected on the fuse wiring layer, thereby further increasing the fusing energy of the fuse wiring layer. becomes possible.

(Embodiment 8) In this Embodiment 8, as shown in FIG. 10, first and second fuse elements 92 and 94, both made of polycrystalline silicon, are connected via a silicon oxide film 18, which is an interlayer insulating layer. The fuse element 90 is formed by forming the fuse element 90 at upper and lower opposing positions and connecting one ends of the two in series through the contact hole 26. The second fuse element 92 in the upper layer is a thin film of, for example, 1000 angstroms or less, and the first fuse element 94 is formed thicker than the second fuse element 92.

When the fuse element 90 is irradiated with a laser beam, the energy thereof is absorbed by the second fuse element 92 in the upper layer. If the misalignment of the laser beam is small, the second fuse element 92 can be blown using the high energy density region shown in FIG. However, when the misalignment becomes large, a region with low energy density is irradiated onto the second fuse element 92. At this time, since the thin film second fuse element 92 absorbs less energy, it may be difficult to blow it out reliably. The laser beam transmitted through the thin-film second fuse element 92 is irradiated onto the first fuse element 94, which has good energy absorption properties due to the relatively thick film formation. Although the energy density of the laser beam incident on the first fuse element 94 is lower than that of the laser beam incident on the first fuse element 94, the energy absorption property is good, so blowing due to heat generation is ensured.

As described above, according to the eighth embodiment, by blowing out either one of the first and second fuse elements 94 and 92 connected in series, the fuse element 90 can be reliably opened.

[0070]

Effects of the Invention According to the first aspect of the invention, since the fuse wiring layer is provided in a plurality of rows at intervals in the wiring width direction and connected in series, the laser beam is largely deviated particularly in the wiring width direction. Even in this case, any one of the fuse wiring layers can always be located within the beam diameter of the laser beam, and the fuse element can be reliably blown out.

According to the second invention, by forming a high melting point metal film at a lower layer position facing the fuse element, the laser beam transmitted through the fuse element is reflected and used as fusing energy for the fuse element. In particular, it is possible to reliably blow out a thin-film fuse element.

According to the third invention, by virtue of the effects of both the first invention and the second invention, the fuse element can be reliably blown out even when a beam misalignment occurs with respect to the thin film fuse element. There is an effect that can be done.

According to the fourth invention, when the misalignment is small, the second fuse element made of a thin upper layer can be blown by the beam with high energy density, and when the misalignment is large, the energy absorption The beam that has passed through the second fuse element with less energy can blow out the first fuse element, which has a relatively thick film and high energy absorption, and can reliably blow out one of the fuse elements connected in series in the upper and lower layers. can.

[Brief explanation of drawings]

FIG. 1 shows a semiconductor device according to a first embodiment of the present invention, in which FIG. 1A is a plan view of a fuse element seen through from above, and FIG. It is an II sectional view of A).

[Figure 2] Effective beam diameter of laser beam and adjacent 2
FIG. 3 is a schematic explanatory diagram showing the arrangement relationship between the book and the fuse wiring layer.

FIG. 3 shows a semiconductor device according to a second embodiment of the present invention, in which FIG. 3A is a plan view of a fuse element seen through from above, and FIG. A) II-II
Cross-sectional view, the same figure (C) is III-III of the same figure (A)
FIG.

FIG. 4 shows a semiconductor device according to a third embodiment of the present invention, in which FIG. 4A is a plan view of a fuse element seen through from above, and FIG. A) IV-I
It is a V sectional view.

FIG. 5 is a plan view of semiconductor devices according to fourth to sixth embodiments of the present invention, seen through from above.

6 shows a cross-sectional structure of a semiconductor device according to a fourth embodiment of the present invention; FIG.
B) is a VI-VI sectional view of FIG. 5, and the same figure (C) is a cross-sectional view of FIG.
It is a VII-VII sectional view of.

7 shows a cross-sectional structure of a semiconductor device according to a fifth embodiment of the present invention, and FIG. 7(A) is a VI-VI cross-sectional view of FIG.
FIG. 5B is a cross-sectional view taken along line VII-VII in FIG.

8 shows a cross-sectional structure of a semiconductor device according to a sixth embodiment of the present invention, and FIG. 8(A) is a VI-VI cross-sectional view of FIG.
FIG. 5B is a cross-sectional view taken along line VII-VII in FIG.

FIG. 9 shows a semiconductor device according to a seventh embodiment of the present invention, in which FIG. 9A is a plan view of a fuse element seen through from above, and FIG. VIII-VI
It is a sectional view II.

10 shows a semiconductor device according to an eighth embodiment of the present invention; FIG. 10A is a plan view of the semiconductor device seen through from above; FIG. )nono IX-I
X cross-sectional view, the same figure (C) is the XX cross-sectional view of the same figure (A),
The same figure (D) is a sectional view taken along the line XI-XI of the same figure (A).

FIG. 11 is a characteristic diagram showing the energy distribution of a laser beam.

FIG. 12 is a characteristic diagram showing the energy distribution of direct incident energy and reflected energy to the fuse interconnect layer when a high melting point metal film is provided below the fuse interconnect layer.

FIG. 13 shows a conventional semiconductor device; FIG. 13A is a plan view of a fuse element seen through from above, and FIG.
B) is a sectional view taken along line XII-XII in FIG.

[Explanation of symbols]

10 Silicon substrate 16, 18, 24 Silicon oxide film 20, 26 Contact hole 22 Aluminum wiring 30 Fuse element 32 Fuse wiring layer 40 Laser beam 50 Fuse element 52 Lower fuse wiring layer 54 Upper fuse wiring layer 60 Fuse element 62 High melting point metal film 70 Fuse element 72 Fuse wiring layer 74 High melting point metal film 80 Fuse element 82 Upper layer fuse element 84 Fuse wiring layer 86 Lower layer fuse element 88 Fuse wiring layer 90 Fuse element 92 Second fuse element 94 First fuse element

Claims (7)

[Claims] 1. A wiring layer formed on a semiconductor substrate, and a fuse element formed as a pattern of a part of the wiring layer and blown by an energy beam, wherein the fuse element is arranged in a width direction of the wiring. 1. A semiconductor device comprising fuse wiring layers arranged in a plurality of columns at intervals, the fuse wiring layers in each column being connected in series. 2. A high melting point metal film formed on a semiconductor substrate, a wiring layer formed on the high melting point metal film with an interlayer insulating layer interposed therebetween, and a part of the wiring layer formed as a pattern, and an energy beam. 1. A semiconductor device comprising: a fuse element which can be blown by a fuse element; and a part of the high melting point metal film is formed in a lower layer position facing the fuse element. 3. A high melting point metal film formed on a semiconductor substrate, a wiring layer formed on the high melting point metal film with an interlayer insulating layer interposed therebetween, and a part of the wiring layer formed as a pattern, and an energy beam. a fuse element that can be blown by a fuse element, the fuse element is composed of fuse wiring layers provided in a plurality of columns at intervals in the wiring width direction, and the fuse wiring layers in each column are arranged in series. A semiconductor device, wherein a portion of the high melting point metal film is formed at a lower layer position facing the fuse wiring layer of each column of the fuse elements. 4. In claim 1 or 3, an effective beam diameter at which the energy beam contributes to blowing out the fuse wiring layer is D, a width of each of the fuse wiring layers is W, and two adjacent A semiconductor device characterized in that, where P is the center pitch of the fuse wiring layer, D>P+W. [Claim 5] In any one of claims 1 to 3,
A semiconductor device characterized in that the thickness of the fuse element is 1000 angstroms or less. 6. A first wiring layer formed on a semiconductor substrate, and a second wiring layer thinner than the first wiring layer, which is formed on the first wiring layer with an interlayer insulating layer interposed therebetween. a wiring layer, a first fuse element formed as a pattern of a part of the first wiring layer, and an upper layer position facing the first fuse element as a part of the pattern of the second wiring layer; 1. A semiconductor device comprising: a second fuse element formed in the first fuse element and connected in series with the first fuse element through a contact hole. 7. The semiconductor device according to claim 6, wherein the second fuse element has a thickness of 1000 angstroms or less.