KR100979358B1 - Fuse free of thermal degradation - Google Patents

Abstract

The present invention provides a semiconductor device capable of increasing the reliability of operation by reducing the area occupied by the fuse in the highly integrated semiconductor device while preventing thermal degradation that may occur during the blowing process of the fuse. The fuse according to the present invention includes a plurality of blowing regions and a common region including a plurality of parallel fuse lines in which one side is connected one-to-one and the other side is connected to each other.

Semiconductors, Fuses, Thermal Degradation

Description

Fuse to prevent thermal deterioration {FUSE FREE OF THERMAL DEGRADATION}

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.

1 is a plan view illustrating a fuse in a conventional semiconductor device.

As shown, it can be seen that the plurality of fuses are not formed side by side and form a certain pattern. Specifically, the positions selectively blown to each of the plurality of fuses are spaced apart by a predetermined interval, but the other side of the non-blowing fuse is formed to have a narrow gap. In other words, when blowing the fuse to cut off the electrical connection, the laser blows only a portion of the fuse to physically blow the fuse without physically blowing the entire fuse so that both sides of the fuse are electrically disconnected.

Recently proposed semiconductor memory devices require a higher degree of integration, and as described above, a plurality of fuses require a plurality of fuses, but the area occupied by the plurality of fuses is not very large. To overcome this, in order to reduce the area occupied by the entire fuse while arranging a plurality of fuses side by side, three fuses are paired as shown in FIG. The gap was narrowed to increase density. In addition, the blowing portions of the fuses included in the pairs are arranged to be opposite to each other to reduce the total area of the fuse box including the plurality of fuse pairs.

As shown in FIG. 1, a plurality of fuses are formed in the fuse box to reduce the total area. However, since each fuse is configured completely independently, unnecessary parts are generated when a common voltage or signal is applied. For example, in a semiconductor memory device, a power supply voltage meaning a logic high level and a ground voltage meaning a logic low level are not only supplied to a plurality of circuits but also used to determine a logic level of a specific signal. It often happens that different voltage levels must be selectively supplied as a common signal. In this case, it may be inefficient to use two fuses in which the two ends of the fuses are completely independent of each other, and a new design of the fuse to increase the density of the semiconductor memory device is required.

In order to solve the above-mentioned conventional problems, the present invention provides a fuse that can reduce the area occupied by the fuse in the highly integrated semiconductor device while preventing thermal degradation that may occur during the blowing of the fuse, thereby increasing the reliability of the operation.

The present invention provides a fuse including a plurality of blowing regions and a common region including a plurality of parallel fuse lines in which one side is connected one-to-one and the other side is connected to each other.

Preferably, the separation distance between the plurality of blowing regions is greater than the separation distance between the plurality of fuse lines.

Preferably. The distance from each blowing area to the other side of the fuse line is 6 times greater than the separation distance between the plurality of blowing areas.

In addition, the present invention provides two blowing regions for selectively connecting two terminals, two connecting lines connected one-to-one to the two blowing regions, and a common node connecting the two connecting lines with one terminal. It provides a fuse comprising a.

Preferably, the separation distance between the two blowing regions is greater than the separation distance between the two connecting lines.

Preferably, the two connecting lines are parallel.

Furthermore, the present invention includes a plurality of blowing regions connected with two terminals, two parallel connecting lines connected with each of the two blowing regions, and a plurality of common nodes connecting the two connecting lines with one terminal. And a fuse, wherein each of the plurality of fuses is disposed such that neighboring fuses and blowing regions are disposed opposite to each other.

Preferably, the separation distance between the two blowing regions is greater than the separation distance between the two connecting lines.

Preferably, each of the plurality of fuses is characterized in that the inlet is open and the outlet has the shape of a blocked funnel.

The present invention is advantageous in that it is free from thermal deterioration in the process of blowing the fuse included in the highly integrated semiconductor device, thereby ensuring reliability of operation.

In addition, the present invention can be suppressed from increasing the area occupied by a plurality of fuses by designing two signals connected to one terminal or two voltage terminals to one common signal, which is suitable for use in highly integrated semiconductor devices. There is this.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a plan view illustrating a fuse in a semiconductor device according to an embodiment of the present invention.

As shown, the fuse has a 'Y' type structure in which two terminals are connected to one common terminal. This can further reduce the total area compared to the fuse in which the connection of both ends of the conventionally connected terminals in common. Specifically, each fuse is composed of two blowing stages including a blowing area and a common stage grouping the two stages together, and the plurality of fuses have an area occupied by the entire blower stage so that each blowing stage is located opposite to each other. Minimizing. In addition, even when fuse blowing is performed by scanning and blowing a laser on the blowing area of each fuse, the minimum distance between fuses can be maintained, thereby ensuring reliability of operation.

However, when the laser is only physically bursted by scanning only one of the two blowing regions, the electrical connection through the other blowing region should be maintained normally. However, since the fuse is made of a material having high thermal conductivity, there is a concern that the operation reliability of the fuse may be lowered when thermal degradation occurs.

3 is a conceptual diagram illustrating a disadvantage of the fuse illustrated in FIG. 2.

As shown, when the laser is scanned in one blowing area (a) of the fuse, physical detonation and the electrical connection are interrupted, and along with the path of ① in the fuse made of a material having high thermal conductivity, the deterioration starts. At this time, assuming that only one blowing area (a) of the fuse is blown and the other blowing area (b) is normally connected, the junction area (②) where the deterioration progressed by the path of ① is connected to the common stage Can go crazy. When the junction area (2) deteriorates, a change (very much) occurs in the resistance value, and even if the other blowing area (b) is not blown, it is difficult to smoothly transmit signals and voltages. In practice, the length of the fuse deteriorates relatively far, due to the material properties of the fuse, which have a higher thermal conductivity than the range where physical breakdown occurs due to scanning of the laser in the blowing area. For example, assuming that the minimum separation distance for escaping the effect of physical breakage caused by the blowing area is about 1.5 μm in radius, the length at which the fuse can deteriorate is about 9 μm.

In order to prevent this phenomenon, the distance between the two blowing regions a and b of the fuse and the junction region ② may be increased. As the distance is longer, it is possible to prevent the bonding region ② from deteriorating even when one of the two blowing regions a and b is blown. However, in this case, the size of the fuse increases or the gap between the fuses increases, which is not suitable for the highly integrated semiconductor device.

4 is a plan view illustrating a fuse in a semiconductor device according to another embodiment of the present invention.

As shown, the fuse comprises two blowing regions (a, b), two connecting lines (a ', b') connected to each of the two blowing regions (a, b) to allow selective connection with the two terminals. ), And a common area ab connecting the ends so that two connection lines are connected to one terminal. In particular, the two blowing regions a and b whose physical damage is determined by the scanned laser are spaced apart by a minimum distance such that they do not affect neighboring blowing regions or connection lines by physical bursting. In addition, the two connection lines (a ', b') are also spaced apart from each other by a minimum distance that can prevent interference or short (short), and are formed in parallel with each other. For reference, the separation distance between two blowing regions a and b is greater than the separation distance between two connecting lines a 'and b'.

Referring to FIG. 4, two connection lines a 'and b' and a common area ab have a shape of a letter 'C' connected to two blowing areas a and b, and according to the present invention, a fuse according to the present invention. The overall shape is characterized by the shape of a funnel with the inlet open and the outlet closed. This structure can prevent deterioration of the junction region ② described with reference to FIG. 3 without significantly inferior in terms of the degree of integration as compared with a plurality of fuses that have been proposed in the past. That is, the laser is scanned in one blowing area (a) of the fuse to cause physical damage, and the conduction of heat generated at that time passes through one connection line (a ') and the other connection line (b') corresponding to the other blowing area (b). And it is difficult to affect the common area ab.

On the other hand, compared to the case where two blowing regions a and b are subsequently used as one common region through the bonding region ②, the fuse of the present invention has two connection lines a 'and b' separated by a predetermined interval. This can increase the area of the fuse box. However, since the two connecting lines (a ', b') are not blown areas, it is sufficient to space them apart by the minimum distance allowed by the design rules, and the design rules can be manufactured to a minimum. More commonly, largely defined. Therefore, when manufacturing a fuse box in consideration of this, it can be said that the extent to which the area is substantially increased due to this.

FIG. 5 is a conceptual diagram for describing an example of a circuit using the fuse illustrated in FIG. 4.

As shown, two fuses in a fuse box consisting of a plurality of fuses are connected between a PMOS transistor and an NMOS transistor to convert one of the power supply voltage VDD and the ground voltage VSS into a signal. It is being used to deliver to the level.

In the conventional case, two independent fuses each have a structure in which one independently applies a power supply voltage VDD and the other one applies a ground voltage VSS. Fuses with two blowing regions, such as Y 'type fuses, are connected to operate in pairs. That is, two different signals B and C or D and E are connected to two blowing regions, and one signal A is connected to the other blowing region. In particular, FIG. 5 illustrates a case in which four signals B, C, D, and E may be selectively connected to one signal A by using two fuses. In addition, as shown in the fuse box, two fuses and two neighboring fuses are also used in the same way in the opposite direction by connecting four signals (2, 3, 4, 5) to one signal (1). Shows. In this case, it is possible to effectively reduce the total use area than conventionally using four fuses independent of each other.

In particular, in a semiconductor memory device, many control signals are commonly used, such as when a specific control signal is to be selectively transmitted to only one node, or simultaneously to two nodes, and a power supply voltage (VDD) or a ground voltage ( In the case of VSS), the application of the present invention, such as the circuit shown in FIG.

As described above, the fuse according to another embodiment of the present invention allows two signals to be selectively connected to one signal while the other blowing area is blown on the other side while the blow region is blown along with the other side blowing. It is possible to smooth the electrical flow at both ends without loss of area. In addition, the present invention can prevent the integration degree even in the case of a fuse box including a plurality of fuses by reversing the arrangement of blowing areas between neighboring fuses.

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 plan view for explaining a fuse in a conventional semiconductor device.

2 is a plan view illustrating a fuse in a semiconductor device according to an embodiment of the present invention.

3 is a conceptual diagram for explaining a disadvantage of the fuse shown in FIG.

4 is a plan view illustrating a fuse in a semiconductor device according to another embodiment of the present invention.

FIG. 5 is a conceptual diagram for explaining an example of a circuit using the fuse shown in FIG. 4. FIG.

Claims (9)

A plurality of blowing regions; And A common area including a plurality of fuse lines, one side of which is connected to the plurality of blowing regions and one side of which is connected to each other A fuse comprising a. The method of claim 1, And the separation distance between the plurality of blowing regions is greater than the separation distance between the plurality of fuse lines. The method of claim 1, And a distance from each blowing area to the other side of the fuse line is six times greater than the separation distance between the plurality of blowing areas. Two blowing regions for allowing selective connection with the two terminals; Two connecting lines connected one to one to the two blowing regions; And Common node connecting the two connection lines with one terminal A fuse comprising a. The method of claim 4, wherein And the separation distance between the two blowing regions is greater than the separation distance between the two connecting lines. The method of claim 5, And the two connection lines are parallel. A plurality of fuses including two blowing regions connected with two terminals, two connecting lines connected with each of the two blowing regions, and a common node connecting the two connecting lines with one terminal, Wherein each of the plurality of fuses is disposed such that neighboring fuses and blowing regions are located opposite to each other. The method of claim 7, wherein The separation distance between the two blowing regions is greater than the separation distance between the two connection lines. The method of claim 7, wherein And each of the plurality of fuses has an inlet opening and an outlet blockage.

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