KR20100008705A - Fuse device and method of operating the same - Google Patents

Abstract

PURPOSE: A fuse device and a method for operating the same are provided to reduce power consumption by performing a programming operation after heating a fuse. CONSTITUTION: A fuse device includes a fuse(F1) and a current applying unit. The fuse has a pre-heated area for programming. The fuse includes at least one of metal and silicide. The current applying unit applies a programming current to the fuse and includes a driving device(Tr1) and a power source. The driving device is connected to the fuse. The power source is connected to the driving device with a conductive connection structure. The connection structure includes a conductive plug(P1) and a wire(W1). The height of the fuse is equal to or smaller than the height of the wire.

Description

Fuse device and method of operating the same

The present disclosure relates to a fuse device and a method of operating the same.

Fuse devices are widely used for repairing defective cells, storing chip identifications and circuit customization in semiconductor memories and logic devices. For example, cells found to be defective cells among a number of cells of a memory device may be replaced with redundant cells by fuse elements. Accordingly, it is possible to solve the problem of lowering yield due to defects in some cells.

The electrical fuse device applies a current to the fuse to perform a programming operation. That is, in the electrical fuse device, a programming operation is performed by using electromigration (EM), joule heating, or the like caused by the current flowing through the fuse.

However, high current / high voltage is required to program conventional electrical fuse devices. As a result, not only the power consumption increases, but also the size of the fuse element increases. Due to these problems, it is not easy to apply the conventional electric fuse device to various electric devices.

In accordance with an aspect of the present invention, a fuse element is provided that is programmed to low current / low voltage.

According to another aspect of the present invention, a method of operating the fuse element is provided.

One embodiment of the invention includes a fuse having a region that is preheated for programming; And current application means for applying a programming current to the fuse.

An insulating layer thinner than other portions may be provided on the preheated area of the fuse.

The current applying means includes a drive element connected to the fuse; And a power source connected to the driving device.

The driving device and the power source may be connected by a connection structure including a conductive plug in contact with the driving device and a wire in contact with the conductive plug, and the fuse may be provided at the same height as or lower than the wire. have.

The fuse may include at least one of metal and silicide.

A plurality of the fuses may be arranged in parallel in a row, and an insulating layer thinner than other portions may be provided on the preheated area of each fuse and the area between them.

Another embodiment of the present invention includes the steps of heating the fuse; And applying a programming current to the heated fuse.

The fuse may be heated using light.

The fuse may be heated by positively focusing or out-focusing the light on the fuse.

An insulating layer thinner than other portions may be provided on the heating area of the fuse, and heating means for heating the fuse may be provided above the heating area.

The fuse may be arranged in plural, may heat at least one of the plurality of fuses, and apply the programming current to at least one selected from the heated fuses.

At least two of the plurality of fuses may be heated simultaneously.

According to an embodiment of the present invention, it is possible to implement a fuse device that is programmed to a low current / low voltage. The size of such a fuse device may be smaller than the conventional fuse device.

Hereinafter, a fuse device and an operation method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this process, the thicknesses of the layers or regions illustrated in the drawings are somewhat exaggerated for clarity. Like numbers refer to like elements throughout.

1 shows a fuse device according to an embodiment of the present invention.

Referring to FIG. 1, a driving device Tr1 is provided on a substrate 100, and a fuse F1 electrically connected to the driving device Tr1 is provided. The driving element Tr1 may have a transistor structure. That is, the driving element Tr1 may include a gate 10 provided on the substrate 100 and first and second impurity regions 20a and 20b provided in the substrate 100 on both sides of the gate 10. have. One of the first and second impurity regions 20a and 20b may be a source region and the other may be a drain region. The first impurity region 20a may be connected to the power source V1 by a connection structure including the first conductive plug P1 and the first wiring W1. In this case, the first conductive plug P1 may be in contact with the first impurity region 20a, and the first wiring W1 may be in contact with the first conductive plug P1. The second impurity region 20b may be connected to one end of the fuse F1 by the second conductive plug P2. Here, the one end of the fuse (F1) may be an anode (A1). The other end of the fuse F1 may be a cathode C1, and the anode A1 and the cathode C1 may be connected to each other by a link L1 therebetween. As viewed from above, the width of anode A1 and cathode C1 may be greater than the width of link L1. The cathode C1 may be grounded.

The first wiring W1 and the fuse F1 may be formed at the same height, and a first insulating layer IL1 covering the driving device Tr1 may be provided between the first wiring W1 and the fuse F1. Can be. Although the first insulating layer IL1 is illustrated as having a single layer structure, the first insulating layer IL1 may have a multilayer structure. The first and second conductive plugs P1 and P2 may be provided in the first insulating layer IL1.

A second insulating layer IL2 may be provided on the first insulating layer IL1 to cover the first wiring W1 and the fuse F1. The thickness of the second insulating layer IL2 on the link L1 of the fuse F1 may be relatively thinner than the thickness of the second insulating layer IL2 of the remaining area. In other words, the trench T1 may be formed in the second insulating layer IL2 above the link L1. The light source LS1 may be provided as a means for heating the link L1 above the trench T1. In this case, the link L1 is a preliminary heating area for the programming of the fuse F1. The light source LS1 may be a source for irradiating the laser 1 to the link L1.

The operating method of the fuse device of FIG. 1 will be briefly described as follows. The operating method of the fuse device according to the present exemplary embodiment may include heating the fuse F1 and applying a programming current to the heated fuse F1. Light, for example, a laser 1 may be used to heat the fuse F1, and a power source V1 and a driving element Tr1 may be used to apply the programming current. By preliminarily heating the link L1 with the laser 1 irradiated from the light source LS1, low current / low voltage programming is possible. This is because when the link L1 is heated, the electrical resistance of the link L1 is increased due to the inherent temperature coefficient of resistance (TCR) of the material of the link L1, or the metal dopants in the link L1 are activated so that a small current / It can also be programmed by voltage. Therefore, it is not necessary to increase the size of the driving element Tr1 to obtain a high programming current / voltage. Also, there is no need to connect the power supply V1 to an external power supply for high current / high voltage supply. That is, the power supply V1 may be connected to an internal power supply (not shown) that supplies low current / low voltage. This means that the power supply V1 is configured to reduce the size of the driving element Tr1.

When heating the link L1 with the laser 1, the speed at which the link L1 is heated can be adjusted according to the focus, intensity, irradiation time, etc. of the laser 1. For example, an out focusing method of heating the link L1 by slightly focusing the laser 1 off the link L1 can prevent the link L1 from being heated too quickly, so programming Control of the operation can be facilitated. However, instead of the out-focusing method, a positive focusing method that accurately focuses the laser 1 on the link L1 may be used. In this case, the heating speed of the link L1 can be controlled by adjusting the intensity and irradiation time of the laser 1. The operation method described with reference to the fuse device of FIG. 1 may be equally applied to fuse devices according to other embodiments of the present invention described below.

In the structure of FIG. 1, the height of the fuse F1 may vary. One example is shown in FIG.

Referring to FIG. 2, the fuse F2 is provided at a height lower than that of the first wiring W1. In this case, the fuse F2 may be formed at the same height as a bit line (not shown) of the cell region, but may not be. The fuse F2 may include an anode A2, a cathode C2 and a link L2 between them A2, C2, similar to the fuse F1 of FIG. 1. The anode A2 may be connected to the second impurity region 20b of the driving element Tr1 by the second conductive plug P2 ', and the cathode C2 may be connected to the third conductive plug P3 and the second wiring ( Ground via W2). The first insulating layer IL1 ′ covering the driving element Tr1 may be provided on the substrate 100, and the fuse F2 may be provided on the first insulating layer IL1 ′. The second conductive plug P2 'may be provided in the first insulating layer IL1'. A second insulating layer IL2 'covering the fuse F2 may be provided on the first insulating layer IL1'. The thickness of the second insulating layer IL2 'on the link L2 of the fuse F2 may be relatively thinner than the thickness of the second insulating layer IL2' of the remaining region. First and second wirings W1 and W2 may be provided on the second insulating layer IL2 ′. The first conductive plug P1 may be provided in the first and second insulating layers IL1 ′ and IL2 ′, and the third conductive plug P3 may be provided in the second insulating layer IL2 ′. A third insulating layer IL3 may be provided on the second insulating layer IL2 ′ except for the upper portion of the link L2 to cover the first and second wirings W1 and W2. In other words, after the second and third insulating layers IL2 ′ and IL3 are sequentially provided on the fuse F2, the third insulating layer IL3 and the second insulating layer having a thickness are formed on the link L2. IL2 ') may be removed to form the trench T2. The light source LS1 may be provided above the trench T2, and the laser 1 may be irradiated onto the fuse F2 from the light source LS1.

In FIG. 2, the connection relationship between the fuse F2 and the driving element Tr1 may be variously changed. An example is shown in FIG. 3.

Referring to FIG. 3, the second impurity region 20b of the driving element Tr1 may be connected to the fuse F2 by the second conductive plug P2 ″, the third wiring W3 and the fourth conductive plug P4. The second conductive plug P2 ″ may be provided in the first and second insulating layers IL1 ′ and IL2 ′ so as to contact the second impurity region 20b, and the fourth conductive plug P2 ″ may be connected to the anode A2. The conductive plug P4 may be provided in the second insulating layer IL2 ′ so as to contact the anode A2, and the third wiring may be connected to connect the second conductive plug P2 ″ and the fourth conductive plug P4. It may be provided on the second insulating layer IL2 ′.

In the fuse device of FIGS. 1 to 3, the insulating layer region to which the laser 1 is irradiated, that is, the insulating layer region at the bottom of the trenches T1 and T2 is formed of a different material from the insulating layer region to which the laser 1 is not irradiated. Can be. An example is shown in FIG. 4.

FIG. 4 is a structure in which all of the second insulating layer IL2 above the link L1 is removed in FIG. 1, and a thinner insulating layer IL2 ″ different from the second insulating layer IL2 is formed on the upper surface of the link L1. The other insulating layer IL2 "may be formed of a material having a physical property suitable for irradiating the laser 1 through the IL2". For example, the second insulating layer IL2 includes silicon oxide. In this case, the other insulating layer IL2 ″ may include silicon nitride. In FIG. 4, the other insulating layer IL2 ″ may be provided on the sidewall of the trench T1 and / or on the top surface of the second insulating layer IL2. In some cases, the second insulating layer IL2 and the fuse may be provided. The structure of FIGS. 2 and 3 may also be modified, similar to that of FIG. 1 modified to FIG.

1 to 4 illustrate the case where the fuses F1 and F2 are provided apart from the substrate 100, in another embodiment of the present invention, the fuses F1 and F2 are disposed inside the substrate 100. It may be provided or in contact with the upper surface of the substrate 100. In addition, the structure of the fuse device may be modified in various ways.

In addition, FIGS. 1-4 and its modified structure may further include a sensing circuit electrically connected to the fuses F1, F2. Configuration of the sensing circuit 300 can be easily understood by those skilled in the art, detailed description thereof will be omitted.

Hereinafter, the types of materials constituting the fuses F1 and F2 and the programming mechanisms thereof according to FIGS. 1 to 4 and its modified structure will be briefly described.

1 to 4 and its modified structure, the fuses F1 and F2 may include metal or silicide and may have a single layer or a multilayer structure. When the fuse F1 is formed at the same height as the first wiring W1 as illustrated in FIG. 1, the fuse F1 may be formed of the same material as the first wiring W1, for example, a metal such as Al or Cu. have. However, in FIG. 1, the fuse F1 and the first wiring W1 may be formed of different materials. 2 or 3, if the fuse F2 is formed at the same height as the bit line (not shown), the fuse F2 may be formed of the material for the bit line, for example, W or WSi. If the fuse F2 is formed at a different level than the bit line, the fuse F2 may be a layer including a silicide material such as NiSi or CoSi. However, the materials of the fuses F1 and F2 specifically mentioned herein are merely exemplary, and the materials of the fuses F1 and F2 may be variously changed.

The programming mechanism of the fuses F1 and F2 may vary depending on the material of the fuses F1 and F2. When the fuses F1 and F2 are formed of a metal, when the programming current is applied to the fuses F1 and F2 heated by the laser 1, the link (e.g., electromigration) and / or joule heating may be used. By cutting off at least a portion of the L1 and L2, a programming operation may be performed in which the fuses F1 and F2 change from a low resistance state to a high resistance state. At this time, the electrical resistance of the fuse (F1, F2) can be increased by more than two times by the heating, thereby low current / low voltage programming is possible. Meanwhile, when the fuses F1 and F2 are formed of silicide such as NiSi or CoSi, when the programming current is applied to the fuses F1 and F2 heated by the laser 1, the metal dopants of the cathodes C1 and C2, For example, a programming operation may be performed by moving Ni or Co toward the anodes A1 and A2 through the links L1 and L2. In more detail, when the metal dopant, for example, Ni or Co, moves to the anodes A1 and A2 by the programming current, a depletion region is generated in the cathodes C1 and C2, and thus the fuse ( A programming operation in which F1 and F2 change from a low resistance state to a high resistance state may be performed. In this case, the metal dopant is activated by the heating, and can easily move to the anodes A1 and A2 even by a low current.

The fuse device according to various embodiments of the present invention described above may be arranged in plural and have a two-dimensional array structure. An example is shown in FIG. 5.

Referring to FIG. 5, a plurality of fuses F parallel to each other are arranged in a line, and a driving element Tr is connected to an anode A of each fuse F. In FIG. The driving elements Tr may be commonly connected to one power source V1. The cathode C of the fuse F may be grounded. A trench region T for irradiating light may be provided on the link L of the fuses F and the region between the links L. FIG. In FIG. 5, the power source V1, the driving device Tr, the fuse F, and the trench region T are the power source V1, the driving device Tr1, the fuse F1 or F2, and the power source V1 of FIGS. 1 to 4, respectively. It may correspond to the trench T1 or T2. In the fuse device of FIG. 5, the trench regions T are formed in common for the plurality of fuses F. However, in some cases, the trench regions T may be individually formed for the fuses F.

The operation method of the fuse device having the array structure as shown in FIG. 5 will be briefly described as follows. Basically, the method of operating the fuse device of FIG. 5 is similar to the method of operating the fuse device of FIGS. 1 to 4. That is, after the fuse F is heated, a programming operation may be performed by applying a current to the heated fuse F. FIG. However, when a plurality of fuses (F) is arranged in an array structure as shown in Figure 4, after heating the plurality of fuses (F) at the same time, the programming current to the at least one fuse (F) selected from among them Can be applied. In this way, since at least one fuse F can be programmed simultaneously, the total programming time can be shortened. However, instead of heating all of the plurality of fuses F, selectively heating only the desired at least one fuse F, and then to all of the heated fuses F, or to at least one of the heated fuses F, A programming current can also be applied. In addition, both the out-focusing method and the positive focusing method described above may be used in the structure of FIG. 4.

As described above, in the embodiment of the present invention, since the programming operation is performed by flowing a current through the heated fuse F after the fuse F is heated, low current / low voltage programming is possible. Therefore, the power consumption can be reduced, and the size of the fuse device can be reduced since it is not necessary to increase the size of the driving device Tr in order to obtain a high current.

In addition, according to the embodiment of the present invention, it is possible to improve the reliability of the programming operation compared to the conventional electric fuse device, it is possible to reduce the interval of the fuse (F). In more detail, when the programming operation is performed only by the current without the aid of a laser, the programming operation may be sudden and explosive, which may damage other fuses around the programmed fuse. Therefore, the reliability of the fuse element can be degraded. However, as in the embodiment of the present invention, if the fuse F is preliminarily heated and a programming operation is performed at a low current / low voltage, the fuse F adjacent thereto is damaged when the specific fuse F is programmed. Is less likely. Therefore, not only can the reliability of the programming operation be improved, but also the spacing of the fuses F can be reduced, thereby further reducing the size of the fuse element.

In addition, when operating the fuse device according to the embodiments of the present invention, it is possible to utilize the laser equipment for the fuse device of the conventional laser blowing method, it is possible to obtain the effect according to the present invention without burdening the facility investment.

The fuse device according to the embodiments of the present invention described above may be repaired in a semiconductor memory device, a logic device, a microprocessor, a field programmable gate array (FPGA) and other very large scale integration (VLSI) circuits, or the like. It can be applied for various purposes such as chip identification storage, circuit customization, and trimming.

While many details are set forth in the foregoing description, they should be construed as illustrative of preferred embodiments, rather than to limit the scope of the invention. For example, those skilled in the art will appreciate that the structure and components of the fuse device of FIGS. 1 to 5 may be changed and varied. As a specific example, the driving elements Tr and Tr1 may have a structure other than a transistor, and the means for heating the fuses F, F1 and F2 may vary. Also, the operation method of the fuse device of FIGS. 1 to 5 may have various modifications. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined by the technical spirit described in the claims.

1 to 4 are cross-sectional views showing fuse devices according to embodiments of the present invention.

5 is a circuit diagram illustrating a fuse device having an array structure according to another exemplary embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

1: laser 10: gate

20a: first impurity region 20b: second impurity region

100: substrate A1, A2: anode

C1, C2: cathode F, F1, F2: fuse

IL1-IL3, IL1 ', IL2', IL2 ": insulating layer L1, L2: link

LS1: Light source P1-P4, P2 ', P2 ": Conductive plug

T, T1, T2: trench Tr, Tr1, Tr2: drive element

V1: power supply W1 to W4: wiring

Claims (12)

A fuse having an area preheated for programming; And And a current application means for applying a programming current to the fuse. The method of claim 1, And an insulating layer thinner than other portions on the preheated region of the fuse. According to claim 1, wherein the current applying means, A driving element connected to the fuse; And And a power source connected to the driving device. The method of claim 3, wherein The driving device and the power supply are connected by a connection structure including a conductive plug in contact with the driving device and a wire in contact with the conductive plug. The fuse is a fuse device provided with the same height or lower than the wiring. The method of claim 1, The fuse device comprises at least one of a metal and silicide. The method of claim 1, A plurality of said fuses arranged in parallel in a row, A fuse device provided with an insulating layer thinner than other portions on the preheated area of each fuse and the area between them. Heating the fuse; And And applying a programming current to the heated fuse. The method of claim 7, wherein And the fuse is heated using light. The method of claim 8, A method of operating a fuse element for heating the fuse by positively focusing or out focusing the light on the fuse. The method of claim 7, wherein An insulating layer thinner than other portions is provided on the heating area of the fuse, And a heating means for heating the fuse above the heating region. The method of claim 7, wherein The fuse is arranged in plurality, Heating at least one of the plurality of fuses, And operating the programming current to at least one selected from the heated fuses. The method of claim 11, A method of operating a fuse device for heating at least two of the plurality of fuses at the same time.

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