TW201438183A - Anti-fuse structure and programming method thereof - Google Patents

Abstract

A method of programming an anti-fuse includes steps as follows. First, an insulating layer is provided. An anti-fuse region is defined on the insulating layer. An anti-fuse is embedded within the anti-fuse region of the insulating layer. The anti-fuse includes at least a first conductor and a second conductor. Then, part of the insulating layer is removed by laser to form an anti-fuse opening in the insulating layer. Part of the first conductor and part of the second conductor are exposed through the anti-fuse opening. After that, a under bump metallurgy layer is formed in the anti-fuse opening to connect the first conductor and the second conductor electrically.

Description

Inverse fuse structure and programming method thereof

The present invention relates to an anti-fuse structure and a programming method thereof, and more particularly to a method for programming an anti-fuse using a laser and using an under bump metallurgy process to turn on the anti-fuse and The resulting anti-fuse structure.

Fuses and anti-fuse are commonly used for line repair on wafers or as stylized link elements. For example, when the fuse and the anti-fuse are used as the line repairing component, the point of use is after the circuit function test on the wafer, and when the circuit is found to have a problem, the fuse can be disconnected or the anti-fuse can be turned on. To rebuild the circuit. Or when the fuse and the anti-fuse are connected to the electronic circuit as the programmable fuse array, taking the fuse as an example, when data is input, according to whether each of the fuses located in the array is turned on, the phase can be Correspondingly, a logical signal of 1 or 0 is provided.

Both the fuse and the anti-fuse are components that operate in exactly the opposite direction. For the fuse, in the untreated state, the fuse is in an on state, and after programming, it will be in an open state. Otherwise, in the untreated state, the reverse fuse is in an open state. After programming, it will be rendered conductive.

Fuses and anti-fuse have been widely used in today's semiconductor components, such as DRAM, SRAM, PROM or FPGA, so the process steps of programming fuses, anti-fuse and other components are integrated and the fuses and anti-fuse can be made More flexible to be programmed, for the direction of today's hard work.

To achieve the above object, the present invention provides a reverse melting structure and a programming method thereof.

In accordance with an embodiment of the present invention, a method of programming an inverse fuse is provided. In an initial stage, an insulating layer is provided to include an anti-fuse region, an anti-fuse is buried in the anti-fuse region of the insulating layer, and the anti-fuse includes at least a first conductor and a second conductor, and then Removing the insulating portion of the portion to form an anti-fuse opening in the insulating layer, and exposing a portion of the first conductor and a portion of the second conductor through the anti-fuse opening, and then forming a bump underlying metal layer The anti-fuse opening is used to electrically connect the first conductor and the second conductor.

In accordance with another embodiment of the present invention, another method of programming an anti-fuse is provided. First, an insulating layer is provided to include an anti-fuse region and a circuit region, an anti-fuse is buried in the anti-fuse region of the insulating layer, and the anti-fuse includes at least a first conductor and a second conductor, and a conductive The pad is buried in the circuit region of the insulating layer, and the conductive pad electrically connects a set of interlayer interconnections, and then a lithography process is performed to remove the insulating layer located in the circuit region and the reverse fuse region to form a conductive pad. Opening a conductive pad and forming a lithography opening over the reverse fuse, and then removing a portion of the insulating layer under the lithographic opening by laser to form a laser opening extending below the lithographic opening and making a portion The first conductor and a portion of the second conductor are exposed by the laser opening, wherein the laser opening and the lithographic opening form an anti-fuse opening, and finally a bump underlying metal layer is formed on the anti-fuse opening and the conductive pad opening. And the under bump metal layer in the anti-fuse opening electrically connects the first conductor and the second conductor.

According to another embodiment of the invention, an inverse fuse structure is provided. The anti-fuse structure includes an anti-fuse disposed in an insulating layer, wherein the anti-fuse includes at least a first conductor and a second conductor, and an anti-fuse opening is disposed between the first conductor and the second conductor a first edge of the first conductor and a second edge of the second conductor are exposed by the reverse fuse opening, and a bump bottom metal layer is disposed in the reverse fuse opening to electrically connect the first An edge and the second edge, wherein the first conductor and the second conductor are electrically connected only by the underlying metal layer of the bump.

10‧‧‧Insulation

12‧‧‧ nitride

14‧‧‧Oxide

16‧‧‧Anti-fuse

18‧‧‧First conductor

20‧‧‧second conductor

22‧‧‧Electrical mat

24‧‧‧Inter-layer connection

26‧‧‧First lithography opening, conductive pad opening

28‧‧‧Second lithography opening

30‧‧‧Laser opening

32‧‧‧Reverse fuse opening, third lithography opening, laser opening

34‧‧‧Bump metal layer

36‧‧‧metal layer

40‧‧‧Anti-fuse structure

181‧‧‧ edge

201‧‧‧ edge

200‧‧‧ circuit area

400‧‧‧Anti-fuse zone

1 to 5 are schematic views of a method of programming an inverse fuse drawn in accordance with a preferred embodiment of the present invention.

2A and 2B are schematic views of different embodiments of a lithography process.

3A and 3B are schematic views of different embodiments of the anti-fuse opening.

5A, 5B, 5C, and 5D are schematic views of different embodiments of the inverse fuse structure.

In the following, specific embodiments of the inverse fuse structure of the present invention and its programming method are set forth so that those skilled in the art can practice the invention. The specific embodiments may be referred to the corresponding drawings, such that the drawings form part of the embodiments. Although the embodiments of the present invention are disclosed as follows, they are not intended to limit the invention, and those skilled in the art can make some modifications and refinements without departing from the spirit and scope of the invention.

Several embodiments will now be provided in conjunction with the drawings to illustrate the method and structure of the present invention. 1 to 5 are schematic views of a programming method of an inverse fuse drawn according to a preferred embodiment of the present invention, wherein FIGS. 2A and 2B are schematic views showing different embodiments of a lithography process, 3A and 3B are schematic views showing different embodiments of the reverse fuse opening, and FIGS. 5A, 5B, 5C, and 5D are schematic views showing different embodiments of the reverse fuse structure.

As shown in FIG. 1, a substrate (not shown) is first provided. The substrate may be a semiconductor substrate, a covered insulating substrate or an epitaxial material. At least one active component, such as an MOS transistor, and an insulating layer are formed on the substrate. The layer 10 is overlaid on the substrate, and the insulating layer 10 defines at least two regions, such as an anti-fuse region 400 and a circuit region 200. The insulating layer 10 may be a single layer or composed of a plurality of layers of materials, such as tantalum oxide, tantalum nitride or other insulating materials. According to this In the embodiment, the insulating layer 10 is preferably composed of tantalum nitride 12 as a lower layer and yttrium oxide 14 as an upper layer, but is not limited thereto. In this embodiment, in the anti-fuse region 400 of the insulating layer 10, at least one anti-fuse 16 is embedded in the insulating layer 10, wherein the anti-fuse 16 includes at least two conductors insulated from each other, for example: A conductor 18 and a second conductor 20, according to a preferred embodiment of the present invention, the first conductor 18 and the second conductor 20 are rectangular strip-shaped metal and are arranged parallel to each other with the longest side length, but not in the above The first conductor 18 and the second conductor 20 may have different shapes and arrangements according to different product requirements. In addition, the first conductor 18 and the second conductor 20 may be copper or other conductive materials, but the first conductor 18 The material of the second conductor 20 may be the same or different. Referring to FIG. 1 , in the circuit region 200 of the insulating layer 10 , a conductive pad 22 is embedded in the insulating layer 10 , and the conductive pad 22 and at least one set of interlayer connection 24 are electrically connected. Pad 22 is preferably aluminum or other electrically conductive material. It should be noted that the reverse fuse 16 of the present invention is formed by the step of forming the interlayer interconnection 24 and the interlayer interconnection 24 at the same time, that is, a plurality of layers are formed in the insulating layer 10 by the same exposure and development etching step. The trench is filled with conductive material in all the trenches. After the trench in the anti-fuse region 400 is filled with the conductive material, the anti-fuse 16 is formed, and the trench in the conductive connection region 200 is filled with the conductive material. That is, it becomes the inter-layer interconnection 24 . Thereafter, a conductive pad 22 is formed over the interlayer interconnect 24, in other words, the reverse fuse 16 is completed prior to the conductive pad 22.

As shown in FIG. 2A, in accordance with a first preferred embodiment of the present invention, a lithography process is performed to form a first lithography opening 26 on the conductive pad 22 of the circuit region 200 and over the reverse fuse region 400. A second lithography opening 28, which is subsequently used as a conductive pad opening 26, the original function of which is used to form only the first lithographic opening 26 such that the conductive pad 22 can pass through the conductive pad opening 26. Exposure to connect solder balls or other conductive wires. However, the present invention additionally utilizes this lithography process to simultaneously form the second lithography opening 28 in the reverse fuse region 400. It is noted that the conductive pad 22 is exposed by the conductive pad opening 26, and the reverse fuse 16 is still buried. In the insulating layer 10, in more detail, the second lithography opening 28 is located directly above the reverse fuse 16 and throughout The second lithography opening 28 is higher than the reverse fuse 16 to facilitate subsequent programming of the reverse fuse 16.

According to the second preferred embodiment of the present invention, please refer to FIG. 2B. In the foregoing lithography process, only the opening of the circuit region 200 can be opened without forming an opening in the inverse fuse region 400, that is, the second. The preferred embodiment only forms the opening of the conductive pad 26 of the circuit region 200.

Please proceed to FIG. 3A from FIG. 2A. After the end of the first preferred embodiment, a laser process is performed to remove the insulating layer 10 at the bottom of the second lithography opening 28 by laser passing through the second lithography opening 28. And removing portions of the first conductor 18 and the second conductor 20 to form a laser opening 30, and even the laser can remove the insulating layer 10 at the bottom of the second lithography opening 28 to the bottom of the laser opening 30, low To the extent of the entire anti-fuse 16, at this point an edge 181/201 of each of the first conductor 18 and the second conductor 20, just a portion of the sidewall of the laser opening 30, in other words the first conductor 18 and the second conductor 20 The respective edges 181/201 are exposed by the laser opening 30. At this time, the second lithography opening 28 and the laser opening 30 together form an inverse fuse opening 32. In this embodiment, the reverse fuse opening 32 The cross section is preferably rectangular.

Please proceed to FIG. 3B from FIG. 2B. If the conductive pad opening 26 is formed in the circuit region 200 via the second preferred embodiment, the laser must be used to completely remove the anti-fuse during the laser process. a portion of the insulating layer 10 directly above the 16 to form a laser opening 32 exposing an edge 181/201 of each of the first conductor 18 and the second conductor 20, and similarly, the laser removes a portion of the first conductor 18 and the second conductor 20, in the present embodiment, the completed laser opening 32 acts as an inverse fuse opening 32, and the cross-section of the reverse fuse opening 32 is preferably rectangular.

Referring to FIG. 3A, in accordance with a third preferred embodiment of the present invention, the insulating layer 10 of the circuit region 200 and the anti-fuse region 400 is simultaneously etched by the lithography process, and a first lithography opening 26 and a film are respectively formed. The third lithography opening 32, the third lithography opening 32 serves as a subsequent reverse fuse opening 32. In contrast to the first preferred embodiment, in the third preferred embodiment, the third lithography opening 32 formed in the inverse fuse region 400 has a lower depth than the second lithography opening of the first preferred embodiment. 28, in more detail, the lithography process in the third preferred embodiment not only etches the insulating layer 10 of the reverse fuse region 400, but also etches part of the first conductor 18 and a portion of the second conductor 20, so After the lithography process is completed, an edge 181/201 of each of the first conductor 18 and the second conductor 20 can be exposed by the reverse fuse opening 32. In this embodiment, the completed first lithography opening 26 serves as a The conductive pad opening 26, the completed third lithography opening 32 acts as an inverse fuse opening 32, and the reverse fuse opening 32 preferably has a rectangular cross section.

In addition, please refer to FIG. 3B, FIG. 3B is a variation of FIG. 3A, and FIG. 3B and FIG. 3A are different in that, in FIG. 3B, whether using a laser process or a lithography process, only Etching the insulating layer 10, for example, by laser etching the insulating layer 10 to form the reverse fuse opening 32, adjusting the parameters of the laser, allowing the laser to etch only the insulating layer 10, when encountering the first conductor 18 and the second In the case of the conductor 20, only the insulating layer 10 on the surfaces of the first conductor 18 and the second conductor 20 is removed, but the first conductor 18 and the second conductor 20 are not damaged. Similarly, if the anti-fuse opening 32 is formed by the lithography process, the etchant etches only the insulating layer 10, and when the first conductor 18 and the second conductor 20 are encountered, only the first conductor 18 and the first The insulating layer 10 on the surface of the two conductors 20 does not damage the first conductor 18 and the second conductor 20. Since only the insulating layer 10 is removed, the cross section of the final reverse fuse opening 32 will form an inverted bottle shape.

The following is an example in which the cross section of the reverse fuse opening 32 is rectangular, and the description will be continued, but the case of the inverted bottle shape is also applicable to the following process. Referring to FIG. 4, a bump underlying metal layer 34 is formed over the surface of the insulating layer 10, the conductive pad opening 26 and the reverse fuse opening 32, and neither the conductive pad opening 26 nor the reverse fuse opening 32 is formed. The material of the under bump metal layer 34 may be a multi-layered structure, and the material may include titanium, copper, tungsten or other conductive materials. Next, a conductive layer, such as a metal layer 36, is formed to cover the surface of the underlying metal layer 34 of the bump. And filling the conductive pad opening 26 and the reverse fuse opening 32, the metal layer 36 may be titanium, copper, tungsten or other conductive material.

As shown in FIG. 5A, the patterned metal layer 36 and the bump underlying metal layer 34 are removed from the metal layer 36 and the under bump metal layer 34 in the inner portion of the reverse fuse opening 32, and the upper surface of the portion of the insulating layer 10 is removed. A portion of the metal layer 36 and the bump underlayer metal layer 34 leave a bump underlayer metal layer 34 at the bottom of the reverse fuse opening 32 and a bump underlayer metal layer 34 and metal layer 36 at the conductive pad opening 26. At this time, the cross section of the under bump metal layer 34 in the anti-fuse opening 32 presents a rectangle, and the under bump metal layer 34 electrically connects the exposed edges 181/201 of the first conductor 18 and the second conductor 20, thereby turning on The anti-fuse 16 and the metal layer 36 in the conductive pad opening 26 can serve as a solder ball or redistribution layer (RDL) wire, a passive component, and a bump underlying metal in the conductive pad opening 26. The layer 34 is used as a buffer layer. Thus, the inverse fuse structure 40 of the present invention has been completed. It is worth noting that in the present embodiment, the reverse fuse 16 is completely turned on only by the under bump metal layer 34, and the reverse fuse opening 32 is provided. There are no other conductive materials except the reverse fuse 16 and the under bump metal layer 34.

In addition, referring to FIG. 5B, this embodiment is another embodiment of the inverse fuse structure 40 of the present invention, which is different from FIG. 5A in the bump bottom layer in the reverse fuse opening 32 in FIG. 5B. The cross section of the metal layer 34 assumes a U shape. In other words, the under bump metal layer 34 is located not only at the bottom of the reverse fuse opening 32 but also on the sidewall of the reverse fuse opening 32.

Furthermore, referring to FIG. 5C, this embodiment is another embodiment of the reverse fuse structure 40 of the present invention, which is different from the 5A diagram: the bumps in the reverse fuse opening 32 in FIG. 5C. The underlying metal layer 34 and the metal layer 36 are not removed, that is, the anti-fuse 16 is electrically connected by the under bump metal layer 34 and the metal layer 36.

After programming the inverse fuse through the inverse fuse programming method of the present invention, the present invention provides the following inverse fuse structure:

As shown in FIG. 5A, in accordance with a preferred embodiment of the present invention, the inverse fuse structure 40 includes an inverse fuse 16, an insulating layer 10, an anti-fuse opening 32 disposed in the insulating layer 10, and a bump. The underlying metal layer 34, wherein the insulating layer 10 may be a single layer or composed of a plurality of layers of material, such as tantalum oxide, tantalum nitride or other insulating materials. According to the embodiment, the insulating layer 10 is preferably composed of tantalum nitride 14 as a lower layer and yttrium oxide 12 as an upper layer, but is not limited thereto. Further, the reverse fuse 16 includes at least one first conductor 18 and a second. The conductor 20, the aforementioned anti-fuse opening 32 is located between the first conductor 18 and the second conductor 20, and the first conductor 18 and the second conductor 20 are preferably rectangular strip-shaped metal with the longest side length of each other. Arranged in parallel with each other, but not limited to the above, the first conductor 18 and the second conductor 20 may have different shapes and arrangements according to different product requirements, and the first conductor 18 and the second conductor 20 may be copper or Other conductive materials, but the materials of the first conductor 18 and the second conductor 20 may be the same or different. Further, the first conductor 18 and the second conductor 20 are both buried in the insulating layer 10 except that an edge 181/201 of each of the first conductor 18 and the second conductor 20 is exposed by the insulating layer 10. In addition, the under bump metal layer 34 is disposed at the bottom of the anti-fuse opening 32 for conducting the first conductor 18 and the second conductor 20. In the embodiment, the cross-section metal layer 34 preferably has a rectangular cross section. And the cross section of the reverse fuse opening 32 is preferably a rectangle. It should be noted that the first conductor 18 and the second conductor 20 are only turned on by the under bump metal layer 34, and the reverse fuse opening 32 has no other than the reverse fuse 16 and the bump underlying metal layer 34. Conductive material.

Referring to FIG. 5B, FIG. 5B illustrates another reverse fuse structure 40 of the present invention. The difference between FIG. 5B and FIG. 5A is that the bump bottom metal layer 34 of FIG. 5B has a U-section. Similarly, in the present embodiment, the first conductor 18 and the second conductor 20 are also electrically connected only by the bump underlying metal layer 34. The other component positions and materials are substantially the same as those in FIG. 5A. Let me repeat.

Referring to FIG. 5C, FIG. 5C illustrates another reverse fuse structure 40 of the present invention. The difference between FIG. 5C and FIG. 5A is that the bump underlying metal layer 34 of FIG. 5C conformally covers the inverse The side walls and the bottom of the fuse opening 32 extend to the upper surface of the insulating layer 10, so that the edges 1810/201 of the first conductor 18 and the second conductor 20 are not exposed. In addition, a metal layer 36 is filled in the anti-fuse opening 32 to cover the under bump metal layer 34. More specifically, the bump underlying metal layer 34 and the metal layer 36 collectively fill the anti-fuse opening 32.

Referring to FIG. 5D, FIG. 5D illustrates another reverse fuse structure 40 of the present invention. The difference between FIG. 5D and FIG. 5A is that the cross-fuse opening 32 in FIG. 5D has an inverted cross section. The shape of the bottle, the other component positions and materials are substantially the same as those in Figure 5A, and will not be described here.

An advantage of the method of programming an anti-fuse disclosed in the present invention is that, in the first preferred embodiment, the second lithography opening 28 is simultaneously etched while etching the conductive pad opening 26 by a lithography process, and then visible on the wafer. The remaining circuit damage condition determines whether or not to continue etching down the second lithography opening 28 using the laser. For example, if the reverse fuse 16 under the second lithography opening 28 is required to repair the circuit, then The laser removes the insulating layer 10 under the second lithography opening 28 to program the reverse fuse 16. Since the reverse fuse opening 32 is opened using a laser, each wafer can be opened to different positions of the reverse fuse opening 32 by laser, and further, since a portion of the reverse fuse opening 32 has been formed by the lithography process, Therefore, when the laser is used subsequently, it does not consume too much energy. In the general process, most of the masks are designed to open the reverse fuse opening, so each wafer is opened with the same position of the reverse fuse opening, and then the unused openings are filled.

In the second preferred embodiment, the reverse fuse opening 32 is fully utilized by the laser, again having the advantage of opening the reverse fuse opening 32 at different locations with a different visual need.

In the third preferred embodiment, the reverse fuse opening 32 is simultaneously etched while etching the conductive pad opening 26 by the lithography process. This process is suitable for setting the circuit of the standard, mass production, for example, in the main circuit After the completion, the customized wafer can be set up by connecting or disconnecting other suitable circuits according to different customer requirements by using the lithography process.

10‧‧‧Insulation

12‧‧‧ nitride

14‧‧‧Oxide

16‧‧‧Anti-fuse

18‧‧‧First conductor

20‧‧‧second conductor

22‧‧‧Electrical mat

24‧‧‧Inter-layer connection

26‧‧‧Electrical pad opening

32‧‧‧Reverse fuse opening

34‧‧‧Bump metal layer

36‧‧‧metal layer

40‧‧‧Anti-fuse structure

181‧‧‧ edge

201‧‧‧ edge

200‧‧‧ circuit area

400‧‧‧Anti-fuse zone

Claims (20)

A method of programming an anti-fuse, comprising: providing an insulating layer comprising an anti-fuse region, an anti-fuse embedded in an anti-fuse region of the insulating layer, the anti-fuse comprising at least a first conductor and a a second conductor; removing the insulating layer from the portion by laser to form an anti-fuse opening in the insulating layer, and exposing a portion of the first conductor and a portion of the second conductor through the anti-fuse opening And forming a bump underlayer metal layer in the anti-fuse opening to electrically connect the first conductor and the second conductor. A method of programming an anti-fuse as described in claim 1, wherein the laser removes only the insulating layer such that the cross-section of the anti-fuse opening is in the shape of an inverted wine bottle. The method of programming an anti-fuse according to claim 1, wherein the laser simultaneously removes a portion of the insulating layer and a portion of the first conductor and a portion of the second conductor such that a cross section of the reverse fuse opening is one rectangle. The method of programming an anti-fuse according to claim 1, wherein the under bump metal layer is located only at the bottom of the anti-fuse opening, and the bump underlying metal layer has a rectangular cross section. The method of programming an anti-fuse according to claim 1, wherein the under bump metal layer is located at a bottom and a sidewall of the anti-fuse opening, and the bump underlying metal layer has a U-shaped cross section. The method of programming an anti-fuse according to claim 1, wherein the insulating layer further comprises a circuit region, a conductive pad is disposed in the insulating layer, and the conductive pad electrically connects a set of interlayer interconnections, and Removing the portion of the circuit region by a lithography process before removing the insulating layer An insulating layer is formed to form a conductive pad opening, and the conductive pad is exposed by the conductive pad opening. The method of programming an anti-fuse according to claim 6, further comprising: simultaneously removing the insulating layer located at a portion directly above the anti-fuse in the anti-fuse region during the lithography process, A lithography opening is formed over the anti-fuse, but after the insulating layer of the portion is removed, the anti-fuse is maintained in the insulating layer. The method of programming an anti-fuse according to claim 6, wherein when the under bump metal layer is formed in the anti-fuse opening, the under bump metal layer is also conformally formed in the conductive pad opening. The method of programming an anti-fuse according to claim 8, further comprising forming a conductive layer in the conductive pad opening and the anti-fuse opening after forming the under bump metal layer. A method of programming an anti-fuse, comprising: providing an insulating layer comprising an anti-fuse region and a circuit region, an anti-fuse embedded in the anti-fuse region of the insulating layer, the anti-fuse comprising at least one a first conductor and a second conductor, a conductive pad buried in the circuit region of the insulating layer, the conductive pad electrically connecting a set of interlayer interconnections; performing a lithography process to remove the bit in the circuit region and the Extending a portion of the insulating layer of the fuse region to form a conductive pad opening to expose the conductive pad, and forming a lithography opening over the reverse fuse; removing the portion of the underlying portion of the lithographic opening by using a laser a layer to form a laser opening extending below the lithographic opening and causing a portion of the first conductor and a portion of the second conductor to be exposed by the laser opening, wherein the laser opening and the lithographic opening comprise An anti-fuse opening; and forming a bump underlayer metal layer on the anti-fuse opening and the conductive pad opening, and the under bump metal layer in the laser opening electrically connects the first conductor and the second conductor. A method of programming an anti-fuse as described in claim 10, wherein the laser removes only a portion of the insulation The layer is such that the cross section of the reverse fuse opening is in the shape of an inverted wine bottle. The method of programming an anti-fuse according to claim 10, wherein the laser simultaneously removes a portion of the insulating layer, a portion of the first conductor, and a portion of the second conductor such that a cross section of the reverse fuse opening is one rectangle. The method of programming an anti-fuse according to claim 10, wherein the under bump metal layer is located only at the bottom of the anti-fuse opening, and the bump underlying metal layer has a rectangular cross section. The method of programming an anti-fuse according to claim 10, wherein the under bump metal layer is located at a bottom and a sidewall of the anti-fuse opening, and the bump underlying metal layer has a U-shaped cross section. The method of programming an anti-fuse according to claim 10, further comprising forming a conductive layer in the conductive pad opening and the anti-fuse opening after forming the under bump metal layer. An anti-fuse structure, comprising: an anti-fuse disposed in an insulating layer, wherein the anti-fuse comprises at least a first conductor and a second conductor; an anti-fuse opening is disposed on the first conductor and the first Between the two conductors, a first edge of the first conductor and a second edge of the second conductor are exposed by the reverse fuse opening; and a bump bottom metal layer is disposed in the reverse fuse opening The first edge and the second edge are electrically connected, wherein the first conductor and the second conductor are electrically connected only by the underlying metal layer of the bump. The anti-fuse structure of claim 16, wherein the first conductor and the second conductor are each a strip of strip metal and are arranged in parallel with each other. The anti-fuse structure of claim 16, wherein the cross-fuse opening has a rectangular or inverted wine bottle shape. The anti-fuse structure of claim 16, wherein the under bump metal layer is located only at the bottom of the anti-fuse opening, and the bump underlying metal layer has a rectangular cross section. The method of programming an anti-fuse according to claim 16, wherein the under bump metal layer is located at a bottom and a sidewall of the anti-fuse opening, and the bump underlying metal layer has a U-shaped cross section.