KR101033980B1 - Fuse structure for high integrated semiconductor device - Google Patents

Abstract

The present invention provides a semiconductor device that can increase the reliability of operation by preventing thermal degradation and corrosion that may occur during the blowing process of the fuse without increasing the area occupied by the fuse. The semiconductor device according to the present invention includes a fuse including a blowing region and first and second regions connected to two different voltage terminals, wherein the first region is composed of two or more different metal layers and one in the second region. It is characterized by consisting of a metal layer.

Semiconductors, Fuses, Thermal Degradation, Copper

Description

Fuse structure for highly integrated semiconductor devices {FUSE STRUCTURE FOR HIGH INTEGRATED SEMICONDUCTOR DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly, to a fuse that is included in a highly integrated semiconductor device and determines whether to transmit an electrical signal or connect two different terminals.

In general, a fuse is defined as a type of circuit breaker that is used to prevent overcurrent from flowing in a line. In other words, the fuse melts itself by the heat generated by the electric current, which can be easily seen in the surrounding life. Fuses keep current flowing under normal conditions, but if they are blown, they permanently block the flow of current until it is replaced with a new one, which is different from a switch that can control the blocking or connection of current flow. have.

The semiconductor device is designed to operate according to a predetermined purpose by injecting impurities into a predetermined region of a silicon wafer or depositing a new material. A representative example is a semiconductor memory device. The semiconductor memory device includes many elements such as transistors, capacitors, and resistors to perform a predetermined purpose, and a fuse is one of them. Fuses are used in various places in semiconductor memory devices, and representative examples thereof include redundancy circuits and power supply circuits. Fuses used in these circuits remain normal during the manufacturing process, but are selectively blown (ie, blown) through various tests after manufacture.

The redundancy circuit will be described in more detail. When a specific unit cell is defective in the semiconductor memory device, a recovery step is performed to replace the spare unit with an extra normal cell. That is, when an address for accessing a defective unit cell is input from the outside, the recovery step stores the address of the defective unit cell so that the redundant normal cell can be accessed instead of the defective unit cell. Prevent access. The most commonly used fuse in this recovery phase is a laser blown through the corresponding fuse in the semiconductor device to blow the fuse and permanently break the place where the electrical connection was maintained. This operation is called fuse blowing.

The semiconductor memory device includes a plurality of unit cells, and no one knows where a defective unit cell exists among the plurality of unit cells after the manufacturing process. Accordingly, in the semiconductor memory device, a fuse box including a plurality of fuses may be provided to replace a normal spare unit cell even if a defect occurs in any of the unit cells.

The data storage capability of the semiconductor memory device is increasing. As a result, the number of unit cells included therein increases, and the number of fuses used to replace a spare unit cell when a defect occurs also increases. On the other hand, the total area of the semiconductor memory device is reduced and high integration is required. As described above, since some of the plurality of fuses selectively blow a laser to physically blow, a predetermined distance between the fuses should be maintained in order not to affect neighboring fuses that are not blown. However, this becomes a factor of lowering the degree of integration of the semiconductor memory device. Therefore, there is a need for a technology that reduces the area occupied by the fuse box and does not cause defects in other fuses even if the fuse is selectively blown.

1 is a block diagram illustrating a fuse in a conventional semiconductor device.

As illustrated, the contacts 102 and 104 are formed in the power supply voltage VDD terminal and the ground voltage VSS terminal 101 and 103, respectively. A fuse 120 made of copper (Cu) is formed on the contacts 102 and 104, and a nitride film 114 is formed on the fuse 120. An insulating film 106 is deposited under the fuse 120, and a passivation layer 116 is formed on the nitride film 114.

In brief, a manufacturing method may be performed by etching the insulating layer 106 to form a contact hole (not shown), and filling the conductive material to form the contacts 102 and 104. Subsequently, after the fuse 120 formed of copper (Cu) is formed, a nitride film 114 is deposited after dama cleaning. Here, dama cleaning is a technique applied to the next-generation metal multilayer wiring technology, and removes a metal oxide layer (metal oxide) formed on the exposed metal wiring before depositing a kind of contact metal. Say.

Referring to FIG. 1, it can be seen that the fuse 120 formed of copper is blown, which means that the fuse 120 is blown. However, it can be seen that a copper (Cu) material, which is a residue 122, still remains in the area where the fuse 120 is blown. In recent years, highly integrated semiconductor devices use copper (Cu) having low resistance as the size and area of wirings, fuses, and the like decrease in resistance, thereby increasing resistance. However, in the case of a material having low strength, high heat conduction, and strong corrosion compared to other metal materials such as copper (Cu), the residues generated by the blowing of the fuse or the materials remaining in the fuse are subjected to high temperature or high humidity conditions. Can be migrated according to their electrochemical properties. Due to the physical properties of the copper, although the fuse should be blown due to blowing, there is a case where the electrical connection occurs, or if a neighboring fuse blows, a problem occurs such as damage to the adjacent fuse.

In order to prevent the above-mentioned disadvantages such as thermal degradation, fuses are manufactured using aluminum or tungsten-based metals having relatively lower thermal conductivity than copper. Due to the high power loss may occur due to processing speed delay or leakage current. In order to overcome this problem, the size of a fuse or a wiring must be increased, resulting in a high integration of semiconductor devices. However, in the case of forming the fuse using copper as described above, since the formation of the fuse is difficult due to the characteristic properties of the copper, a new fuse suitable for a highly integrated semiconductor memory device is required.

In order to solve the above-described problems, the present invention is to reduce the thickness of the conductive material constituting the fuse when forming the fuse in the semiconductor device to reduce the mobility of the conductive material in the blowing process, the semiconductor device that occurs after the blowing process It provides technology that can prevent malfunction and increase the reliability of operation.

The present invention includes a fuse including a blowing region and first and second regions connected to two different voltage terminals, wherein the first region includes two or more different metal layers, and the second region includes one metal layer. A semiconductor device is provided.

Preferably, the second region is characterized in that it comprises copper (Cu).

Preferably, the first region includes at least one metal layer of a copper (Cu) layer, a tungsten (W) layer, and an aluminum (Al) layer.

The method may further include a plurality of contacts for connecting the two different voltage terminals with the first region and the second region, respectively.

Preferably, the ground voltage is connected to the second region, and the power supply voltage is connected to the first region.

Preferably, the first region comprises a first metal layer formed of a first metal material; And a second metal layer formed on the first metal layer, wherein a thickness of a portion of the region in the first metal layer positioned below the second metal layer is thinner than the second region.

Preferably, the blowing area occupies about 20% of the total length of the fuse in plan view, and the second metal layer occupies about 30 to 35% of the total length of the fuse in plan view.

Preferably, the second metal layer is formed in one or more patterns, the size of the pattern is characterized in that determined by the number of patterns.

Preferably, the pattern is characterized in that one of the concavo (concavo) form, columnar form and cylinder form.

Preferably, further comprising a nitride film for protecting the upper portion of the first metal layer and the upper portion of the second region.

Preferably, the first region comprises a first metal layer formed of a first metal material; And a second metal layer formed through the first metal layer, wherein the first metal layer is removed below the second metal layer.

The method may further include a contact for connecting one of the two different voltage terminals to the first region, wherein the second metal layer is formed by invading a portion of the contact region.

Preferably, one of the two different voltage terminals and the second metal layer are directly connected without a contact for connecting the first region.

Preferably, the first region occupies about 40% of the total length of the fuse.

Preferably, the second metal layer is formed of a laminated structure of tungsten and aluminum, characterized in that occupies about 30 to 35% of the total length of the fuse on the plane.

According to the present invention, when a fuse included in a highly integrated semiconductor device is formed of copper (Cu), an error that may occur after a blowing process may be eliminated due to the physical properties of copper, thereby securing reliability of operation. have.

Furthermore, the present invention can prevent the thermal deterioration or the movement of residues while blowing the fuse while forming a fuse using copper, so that the fuse can have a low resistance value can prevent power loss due to processing speed delay or leakage current, etc. have.

The present invention, despite the use of copper to form a fuse in order to prevent the power loss caused by the processing speed delay or leakage current due to the increased resistance as the fuse size is reduced as the integration of the semiconductor device increases In the blowing process of a specific fuse, the present invention proposes a structure that can stably blow and prevent thermal deterioration of neighboring fuses due to residues.

In the case of a semiconductor device according to an embodiment of the present invention in which a fuse is formed using copper (Cu), there are several methods for overcoming a disadvantage that may occur due to physical properties of copper. First, there is a method of reducing the potential difference between both ends of the fuse during the blowing process. When the power supply voltage VDD and the ground voltage VSS are applied to both ends of the fuse, a potential difference between the two voltages causes pieces of copper (Cu), which are residues of the fuse, to be easily moved by an electric field. Therefore, if the potential difference is reduced by applying the ground voltage VSS across the fuse, it is possible to prevent the residues of the fuse from being moved by the electric field. Second, there is a nitride film formed after the dama cleaning is performed on the fuse formed of copper (Cu), to strengthen the contact force by changing the interface characteristics between the copper (Cu) and the nitride film (nitride) In this case, even if the fuse is blown, it is possible to prevent the copper (Cu) material remaining in the remaining area except the blowing area. Finally, there is a method of reducing the amount of copper (Cu) to form a fuse to significantly reduce the amount of residue that can move according to the electrical or chemical environment after blowing. In this case, it is important to reduce the amount of copper (Cu) constituting the fuse and not to increase the resistance value of the fuse. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2A and 2B are cross-sectional views and a plan view illustrating a fuse in a semiconductor device according to an embodiment of the present invention.

Referring to FIG. 2A, contacts 202 and 204 are formed on a power supply voltage VDD terminal and a ground voltage VSS terminal 201 and 203, respectively. A fuse 220 made of copper (Cu) is formed on the contacts 202 and 204, and a nitride film 214 is formed on the fuse 220. An insulating film 206 is deposited under the fuse 220, and a passivation layer 216 is formed on the nitride film 214. Here, the fuse 220 includes a blowing region 222 that may be blown during a blowing process, a first region 230 connected to a power supply voltage VDD, and a second region 240 connected to a ground voltage VSS. . Unlike the related art, the first region 230 may include two or more different metal layers. Specifically, the first region 230 includes a first metal layer 226 and a second metal layer 232 formed on the first metal layer 226, and the second region 240 is a first metal layer. Only metal layer 226 is included.

The first metal layer 226 may be made of copper (Cu), the structure of the fuse 220 according to the present invention can overcome the disadvantages due to the physical properties of copper (Cu). Specifically, referring to the first region 230, after etching a portion of the first metal layer 226 and the nitride layer 214, the second metal layer 232 is formed. Therefore, in the first region 230, the thickness of the first metal layer 226 under the second metal layer 232 is thinner than that of the first metal layer 226 of the second region 240. That is, the amount of copper (Cu) forming the fuse 220 in the first region 230 is reduced as the thickness is reduced, greatly reducing the amount of copper residues that can move according to the electrical or chemical environment after the blowing process.

Referring to FIG. 2A, the second metal layer 232 is formed in a concavo pattern on the first metal layer 226 and the nitride layer 214. However, the second metal layer 232 may also be formed in a pillar shape or a cylinder shape. In the present invention, due to the formation of the second metal layer 232, which may be formed of tungsten (W) or aluminum (Al), the first metal layer in the fuse 220 without increasing the resistance value of the entire fuse 220 ( The amount of copper (Cu) constituting 226 can be greatly reduced.

2B, the blown fuse 220A and the non-blowing fuse 220B are described after the blowing process. Assuming that the entire length of the fuse 220 is about 10 μm, the blowing area 222 occupies about 2 μm at the center of the fuse 220, and the first area 230 and the second area 240 are about 4 μm. Occupies. In this case, the second metal layer 232 formed in the first region 230 occupies about 3 to 3.5 μm in plan view. The overall length of the fuse 220 and the length of each of the blowing region 222, the first region 230, and the second region 240 are merely one embodiment, and the fuse 220 may be blown. It can be changed according to the means used for the semiconductor device design or the process margin. However, as the area and length of the planar portion occupied by the second metal layer 232 in the first region 230 become wider, the volume of the first metal layer 226 included in the first region 230 can be reduced.

3A and 3B are cross-sectional views and a plan view illustrating a pair of fuses in a semiconductor device according to another embodiment of the present invention.

Referring to FIG. 3A, contacts 302 and 304 are formed in a power supply voltage VDD terminal and a ground voltage VSS terminal 301 and 303, respectively. A fuse 320 made of copper (Cu) is formed on the contacts 302 and 304, and a nitride film 314 is formed on the fuse 320. An insulating film 306 is deposited under the fuse 320, and a passivation layer 316 is formed on the nitride film 314. Here, the fuse 320 includes a blowing area 322, a first area 330, and a second area 340, and unlike the embodiment of FIG. 2A, the second metal layer included in the first area 330. Characteristic is that 332 is formed in a plurality of patterns instead of one. In this case, each pattern may be formed in a concave form, a pillar form or a cylinder form.

Referring to FIG. 3B, the blown fuse 320A and the non-blown fuse 320B are described after the blowing process. It is partially similar to the fuses 220A and 220B described in FIG. 2B, except that the second metal layer 332 is formed in a plurality of patterns. Although the second metal layer 332 is formed in a plurality of patterns, the position of the pattern closest to the blowing region 322 among the plurality of patterns constituting the second metal layer 332 is used to determine the amount of residue after the blowing process. It is important. This is because the second metal layer 332 may be formed of a metal having different physical properties from copper (Cu) used as the first metal layer 326, thereby preventing problems such as thermal degradation due to the blowing process.

4A and 4B are cross-sectional views and a plan view illustrating a pair of fuses in a semiconductor device according to still another embodiment of the present invention.

Referring to FIG. 4A, contacts 402 and 404 are formed in a power supply voltage VDD terminal and a ground voltage VSS terminal 401 and 403, respectively. A fuse 420 made of copper (Cu) is formed on the contacts 402 and 404, and a nitride film 414 is formed on the fuse 420. An insulating film 406 is deposited under the fuse 420, and a passivation layer 416 is formed on the nitride film 414. As in other embodiments, the fuse 420 is composed of a blowing area 422, a first area 430, and a second area 440. However, unlike the embodiment described with reference to FIGS. 2A through 3B, the second metal layer 432 included in the first region 430 penetrates through the first metal layer 426 to be in contact with the contact 402. There is. The first region 430 preferably occupies 40% of the total length of the fuse 420. In addition, the second metal layer 432 may occupy 30 to 35% of the total length of the fuse 420. In addition, the second metal layer 432 has a laminated structure in which the tungsten layer 432A and the aluminum layer 432B are sequentially stacked, but the structure of the second metal layer 432 may be changed according to an embodiment. .

Since the second metal layer 432 penetrates the first metal layer 426 and invades a portion of the contact 402, the amount of the first metal layer 426 may be greatly reduced. While the volume of the first metal layer 426 is greatly reduced, the cross-sectional area of the contact 402 connected to the fuse 420 is widened so that the overall resistance value is not significantly different.

Referring to FIG. 4B, a blown fuse 420A is described after a blowing process, similar to the fuses 220A and 320A described in FIG. 2B or 3B, and in plan view, the second metal layer 432 includes a plurality of metal layers. There is a difference in having this laminated structure. Although the second metal layer 432 is formed in a laminated structure, the larger the area occupied by the second metal layer 432 in the first region 430, the more the amount of residue generated after the first metal layer 426 is blown. Can be reduced.

In FIG. 4A, the second metal layer 432 penetrates through the first metal layer 426 and invades a portion of the contact 402. However, in another embodiment of the present invention, the power supply voltage (VDD) terminal 401 is formed. The second metal layer 432 may be directly connected to the power supply voltage VDD terminal 401 without forming a contact 402 for connecting the fuse 420 to the fuse 420.

As described above, the semiconductor device according to the embodiment of the present invention includes a fuse including a blowing region and first and second regions connected to two different voltage terminals, one of the first and second regions being two The above is composed of different metal layers and the other is composed of one metal layer. In particular, when the fuse in the semiconductor device according to the embodiment of the present invention is applied to the case where both the first region and the second region include copper (Cu), the disadvantages due to the physical properties of the copper can be overcome.

The semiconductor device according to the embodiment of the present invention forms another metal layer relatively free from thermal deterioration in a non-blowing region in a fuse formed by using a metal material such as copper, thereby preventing from moving or thermal deterioration of residues generated after the blowing process. It can protect other components. As a result, not only the phenomenon in which the fuse is not blown completely, but also the power loss due to the processing speed delay or leakage current of the semiconductor device can be prevented and the operation reliability can be improved.

It will be apparent to those skilled in the art that various modifications, additions, and substitutions are possible, and that various modifications, additions and substitutions are possible, within the spirit and scope of the appended claims. As shown in Fig.

1 is a block diagram illustrating a fuse in a conventional semiconductor device.

2A and 2B are cross-sectional views and plan views illustrating a fuse in a semiconductor device according to an embodiment of the present invention.

3A and 3B are a cross-sectional view and a plan view for describing a pair of fuses in a semiconductor device according to another embodiment of the present invention.

4A and 4B are cross-sectional and plan views illustrating a pair of fuses in a semiconductor device according to still another embodiment of the present invention.

Claims (15)

And a fuse including a blowing region and first and second regions connected to two different voltage terminals, wherein the first region includes two or more different metal layers connected vertically, and the second region includes one metal layer. And a semiconductor device. Claim 2 has been abandoned due to the setting registration fee. The method of claim 1, And the second region comprises copper (Cu). Claim 3 was abandoned when the setup registration fee was paid. The method of claim 2, And the first region includes at least two metal layers of a copper (Cu) layer, a tungsten (W) layer, and an aluminum (Al) layer. Claim 4 was abandoned when the registration fee was paid. The method of claim 1, And a plurality of contacts for connecting the two different voltage terminals with the first region and the second region, respectively. Claim 5 was abandoned upon payment of a set-up fee. The method of claim 1, A ground voltage is connected to the second region, and a power supply voltage is connected to the first region. Claim 6 was abandoned when the registration fee was paid. The method of claim 1, The first area is A first metal layer formed of a first metal material; And A second metal layer formed on the first metal layer; The thickness of the partial region in the first metal layer located below the second metal layer is thinner than the thickness of the first metal layer formed in the second region. Claim 7 was abandoned upon payment of a set-up fee. The method of claim 6, And the blowing area occupies 20% of the total length of the fuse in plan view, and the second metal layer occupies 30-35% of the entire length of the fuse in plan view. Claim 8 was abandoned when the registration fee was paid. The method of claim 6, The second metal layer is formed in one or more patterns, the size of the pattern is a semiconductor device, characterized in that determined by the number of patterns. Claim 9 was abandoned upon payment of a set-up fee. The method of claim 8, The pattern is a semiconductor device, characterized in that one of the concave (concave), columnar and cylindrical form. Claim 10 was abandoned upon payment of a setup registration fee. The method of claim 7, wherein And a nitride film for protecting an upper portion of the first metal layer and an upper portion of the second region. Claim 11 was abandoned upon payment of a setup registration fee. The method of claim 1, The first area is A first metal layer formed of a first metal material; And A second metal layer formed through the first metal layer, And the first metal layer is removed below the second metal layer. Claim 12 was abandoned upon payment of a registration fee. The method of claim 11, And a contact for connecting the first region with one of the two different voltage terminals, wherein the second metal layer is formed by invading a portion of the contact region. Claim 13 was abandoned upon payment of a registration fee. The method of claim 11, And one of the two different voltage terminals and the second metal layer are directly connected without a contact for connecting the first region. Claim 14 was abandoned when the registration fee was paid. The method of claim 11, And the first region occupies 40% of the total length of the fuse. Claim 15 was abandoned upon payment of a registration fee. The method of claim 14, And the second metal layer is formed of a laminated structure of tungsten and aluminum, and occupies 30 to 35% of the total length of the fuse in plan view.

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