阅读说明：本技术 反熔丝结构 (Anti-fuse structure ) 是由 黄庆玲 施江林 于 2020-05-11 设计创作，主要内容包括：本发明公开了一种反熔丝结构,包含基板、主动层、电极层以及介电层。主动层位于基板上方,且具有主体以及由主体凸出的凸部。电极层位于主动层上方且部分重叠主动层的凸部。电极层具有镂空区域,且主动层的凸部位于镂空区域中。介电层位于主动层与电极层之间。借此,本发明的反熔丝结构,借由上述设置,可降低反熔丝结构失效的机率。(The invention discloses an anti-fuse structure, which comprises a substrate, an active layer, an electrode layer and a dielectric layer. The active layer is located above the substrate and has a body and a protrusion protruding from the body. The electrode layer is located above the active layer and partially overlaps the convex part of the active layer. The electrode layer is provided with a hollow area, and the convex part of the active layer is positioned in the hollow area. The dielectric layer is located between the active layer and the electrode layer. Therefore, the anti-fuse structure can reduce the failure probability of the anti-fuse structure by the arrangement.)

1. An antifuse structure, comprising:

a substrate;

an active layer over the substrate, wherein the active layer has a body and a protrusion protruding from the body;

an electrode layer located above the active layer and partially overlapping the convex portion of the active layer, wherein the electrode layer has a hollow area, and the convex portion of the active layer is located in the hollow area; and

and the dielectric layer is positioned between the active layer and the electrode layer.

2. The antifuse structure of claim 1, wherein the protrusion of the active layer has an end segment surrounded by the electrode layer.

3. The antifuse structure of claim 2, wherein a width of the hollowed-out region is greater than a width of the end section of the protrusion of the active layer.

4. The antifuse structure of claim 1, wherein the area of the hollowed-out region is a, the area of the electrode layer is B, and a ratio of a to (a + B) is in a range from 0.3 to 0.4.

5. The antifuse structure of claim 1, further comprising a conductive layer over the electrode layer and covering the hollowed-out region.

6. The antifuse structure of claim 5, further comprising:

a first conductive structure extending upwardly from the conductive layer; and

a second conductive structure extending upward from the active layer.

7. The antifuse structure of claim 5, further comprising a protective structure surrounding the electrode layer and the conductive layer.

8. The antifuse structure of claim 7, wherein the dielectric layer is further located between the active layer and the protection structure.

9. The antifuse structure of claim 1, wherein the hollowed-out region is rectangular in shape.

10. The antifuse structure of claim 1, wherein corners of the hollowed-out region have arc-shaped segments.

11. The antifuse structure of claim 1, further comprising a protective structure surrounding the electrode layer.

12. The antifuse structure of claim 1, wherein sidewalls of the body of the active layer are flush with sidewalls of the electrode layer.

13. The antifuse structure of claim 1, wherein the dielectric layer has a thickness betweenToIn the range of (1).

14. The antifuse structure of claim 1, wherein the protrusion of the active layer has a segment overlapping with the electrode layer, the segment has an area C, the protrusion of the active layer has an area D, and a ratio of C to D is in a range of 0.4 to 0.5.

15. The antifuse structure of claim 1, further comprising an insulating structure between the substrate and the active layer.

16. The antifuse structure of claim 15, wherein a vertical projected area of the active layer on the substrate completely overlaps a vertical projected area of the insulating structure on the substrate.

Technical Field

The invention relates to an anti-fuse structure.

Background

In recent years, antifuse technology has attracted attention from many inventors, integrated circuit designers, and manufacturers. An antifuse is a structure that can be switched to a conductive state, i.e., an electronic device, from a non-conductive state to a conductive state. Specifically, the antifuse structure is in an initial state (i.e., an off state) and has a high resistance before a voltage is applied to the antifuse structure. The antifuse structure forms a permanent circuit path when a voltage is applied beyond a certain level.

Disclosure of Invention

The present invention is directed to an antifuse structure, which can reduce the probability of failure of the antifuse structure.

According to an embodiment of the present invention, an antifuse structure includes a substrate, an active layer, an electrode layer, and a dielectric layer. The active layer is located above the substrate and has a body and a protrusion protruding from the body. The electrode layer is located above the active layer and partially overlaps the convex part of the active layer. The electrode layer is provided with a hollow area, and the convex part of the active layer is positioned in the hollow area. The dielectric layer is located between the active layer and the electrode layer.

In one embodiment of the present invention, the convex portion of the active layer has an end segment surrounded by the electrode layer.

In an embodiment of the invention, a width of the hollow area is greater than a width of the end section of the convex portion of the active layer.

In an embodiment of the invention, the area of the hollow area is a, the area of the electrode layer is B, and a ratio of a to (a + B) is in a range from 0.3 to 0.4.

In an embodiment of the invention, the anti-fuse structure further includes a conductive layer located on the electrode layer and covering the hollow area.

In an embodiment of the invention, the antifuse structure further includes a first conductive structure and a second conductive structure, the first conductive structure extends upward from the conductive layer, and the second conductive structure extends upward from the active layer.

In an embodiment of the invention, the anti-fuse structure further includes a protection structure surrounding the electrode layer and the conductive layer.

In one embodiment of the present invention, the dielectric layer is further located between the active layer and the protection structure.

In an embodiment of the invention, the shape of the hollow area is rectangular.

In an embodiment of the present invention, the corners of the hollow area have arc-shaped sections.

In an embodiment of the invention, the anti-fuse structure further includes a protection structure surrounding the electrode layer.

In one embodiment of the present invention, the sidewalls of the body of the active layer are substantially flush with the sidewalls of the electrode layer.

In one embodiment of the present invention, the dielectric layer has a thickness betweenToIn the range of (1).

In one embodiment of the present invention, the protrusion of the active layer has a segment overlapping with the electrode layer, the area of the segment is C, the area of the protrusion of the active layer is D, and the ratio of C to D is in the range of 0.4 to 0.5.

In an embodiment of the invention, the antifuse structure further includes an insulating structure located between the substrate and the active layer.

In an embodiment of the invention, a vertical projection area of the active layer on the substrate completely overlaps a vertical projection area of the insulating structure on the substrate.

According to the above-mentioned embodiment of the anti-fuse structure of the present invention, since the electrode layer has the hollow region and the convex portion of the active layer is located in the hollow region, the current generated by the applied voltage can flow through the electrode layer through two paths before reaching the dielectric layer. In other words, in the event of a failure of either of the two paths, current may flow through the electrode layer via the other of the two paths. Therefore, the failure probability of the anti-fuse structure can be reduced.

Drawings

In order to make the aforementioned and other objects, features, and advantages of the invention, as well as others which will become apparent, reference should be made to the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic diagram of an antifuse structure according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of the anti-fuse structure of FIG. 1 along line 2-2;

FIG. 3 illustrates an active layer and an electrode layer of the antifuse structure of FIG. 1;

FIG. 4 shows an active layer and an electrode layer of an antifuse structure according to another embodiment of the present invention;

FIG. 5 shows an active layer and an electrode layer of an antifuse structure according to another embodiment of the present invention.

Description of the main reference numerals:

100-antifuse structure, 120a, 120 b-active layer, 121-side wall, 122-body, 123-segment, 124-protrusion, 125-end segment, 130a, 130 b-electrode layer, 133-bottom surface, 135-outer edge, side wall, 137-inner edge, 140-dielectric layer, 150-conductive layer, 160-first conductive structure, 162-vertical portion, 163-bottom surface, 164-horizontal portion, 170-second conductive structure, 172-vertical portion, 173-bottom surface, 174-horizontal portion, 200-first barrier layer, 210-second barrier layer, 220-first protective structure, 221-top surface, 230-second protective structure, 231-top surface, 233-bottom surface, 240-insulating structure, 242-body, 244-protrusion, HR-hollowed-out region, CR-corner, R-region, T1, T2, T3-thickness, W1, W2-width, P1, P2-path, 2-2-line segment.

Detailed Description

In the following description, numerous implementation details are set forth in order to provide a thorough understanding of the present invention. It should be understood, however, that these implementation details are not to be interpreted as limiting the invention. That is, in some embodiments of the invention, such implementation details are not necessary. In addition, for the sake of simplicity, some conventional structures and elements are shown in the drawings in a simple schematic manner.

It will be understood that relative terms, such as "lower" or "bottom" and "upper" or "top," may be used herein to describe one element's relationship to another element as illustrated. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures. For example, if the device in one of the figures is turned over, elements described as being on the "lower" side of other elements would then be oriented on "upper" sides of the other elements. Thus, the exemplary term "lower" can include both an orientation of "lower" and "upper," depending on the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as "below" or "beneath" other elements would then be oriented "above" the other elements. Thus, the exemplary terms "below" or "beneath" can encompass both an orientation of above and below.

It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements present. As used herein, "connected" may refer to physical and/or electrical connections. Further, "electrically connected" or "coupled" may mean that there are additional elements between the two elements.

Fig. 1 is a schematic diagram of an antifuse structure 100 according to an embodiment of the invention. Fig. 2 is a cross-sectional view of the antifuse structure 100 of fig. 1 along line 2-2. Referring to fig. 1 and 2, the anti-fuse structure 100 includes a substrate 110, an active layer 120, an electrode layer 130, and a dielectric layer 140. The active layer 120 is disposed above the substrate 110 and has a body 122 and a protrusion 124 protruding from the body 122. The electrode layer 130 is disposed above the active layer 120 and partially overlaps the protrusion 124 of the active layer 120. The electrode layer 130 has a hollow region HR. The dielectric layer 140 is located between the active layer 120 and the electrode layer 130. In some embodiments, the active layer 120 and the electrode layer 130 may comprise conductive materials, and the dielectric layer 140 may comprise a high resistance insulating material (e.g., oxide). In addition, the thickness T1 of the electrode layer 130 is in the range of 45 nm to 55 nm, but not limited thereto.

When a low voltage is applied to the antifuse structure 100, the dielectric layer 140 remains intact and insulated, and a low current generated by the low applied voltage cannot flow through the dielectric layer 140. The antifuse structure 100 in this case is in an "off" state. When the applied voltage exceeds a certain level, the dielectric layer 140 is broken down by a high current generated by the high applied voltage and forms a permanent circuit path from the electrode layer 130 to the active layer 120. The antifuse structure 100 in this case is in an "on" state (or "conductive" state). The user can calculate the resistance value according to the current value, and further know whether the antifuse structure 100 is in an "off" state or an "on" state.

Since the electrode layer 130 has a hollow region HR and the protrusion 124 of the active layer 120 is located in the hollow region HR, the current generated by the applied voltage can flow through the electrode layer 130 through two paths before reaching the dielectric layer 140. In other words, in the event of a failure of either of the two paths, current may flow through the electrode layer 130 via the other of the two paths. As a result, the probability of failure of the antifuse structure 100 can be reduced.

In some embodiments, the anti-fuse structure 100 further includes at least one conductive layer 150 located above the electrode layer 130 and covering the hollow region HR. For example, as shown in fig. 2, the antifuse structure 100 may include three conductive layers 150 stacked over the electrode layer 130. However, the number of the conductive layers 150 can be adjusted according to the needs of the designer. In addition, when the number of the conductive layers 150 is plural, the vertical projection areas of each conductive layer 150 on the substrate 110 completely overlap each other.

In some embodiments, the antifuse structure 100 further comprises at least one first conductive structure 160 and at least one second conductive structure 170. The first conductive structure 160 extends upward from the conductive layer 150, and the second conductive structure 170 extends upward from the active layer 120. For example, as shown in fig. 2, the first conductive structure 160 has two vertical portions 162 extending parallel to each other over the conductive layer 150, and the second conductive structure 170 has two vertical portions 172 extending parallel to each other over the body 122 of the active layer 120. In an alternative embodiment, one of the two vertical portions 162 of the first conductive structure 160 stands above the hollow region HR, and the other of the two vertical portions 162 of the first conductive structure 160 stands above the electrode layer 130.

In some embodiments, the first conductive structure 160 further includes a horizontal portion 164 disposed above the two vertical portions 162. The horizontal portion 164 extends laterally over the two vertical portions 162 of the first conductive structure 160. In other words, the horizontal portion 164 extends in a direction perpendicular to the extending direction of the two vertical portions 162. In some embodiments, the two vertical portions 162 are integrally formed with the horizontal portion 164 and there is no interface between the two. In some embodiments, horizontal portion 164 is a separate element (e.g., a trace, wire, or other conductive element) that connects two vertical portions 162.

In some embodiments, the second conductive structure 170 further includes a horizontal portion 174 disposed above the two vertical portions 172. The horizontal portion 174 extends laterally over the two vertical portions 172 of the second conductive structure 170. In other words, the horizontal portion 174 extends in a direction perpendicular to the direction in which the two vertical portions 172 extend. In some embodiments, the two vertical portions 172 are integrally formed with the horizontal portion 174 and there is no interface between the two. In some embodiments, horizontal portion 174 is a separate element (e.g., a trace, wire, or other conductive element) that connects two vertical portions 172.

Specifically, the anti-fuse structure 100 can be electrically connected to an external electronic device through the first conductive structure 160 and the second conductive structure 170. For example, the first conductive structure 160 electrically connects the electrode layer 130 of the antifuse structure 100 with an external electronic device, and the second conductive structure 170 electrically connects the active layer 120 of the antifuse structure 100 with another external electronic device.

When the antifuse structure 100 is in an "on" state, a current generated by an applied voltage flows from an external electronic device to the first conductive structure 160, and sequentially flows through the electrode layer 130, the active layer 120, and the second conductive structure 170 to another external electronic device.

In some embodiments, the antifuse structure 100 further comprises a first barrier layer 200 and a second barrier layer 210. The first barrier layer 200 is located between the two vertical portions 162 of the first conductive structure 160 and the conductive layer 150, surrounds the two vertical portions 162 of the first conductive structure 160, and is located on the bottom surface 163 of the horizontal portion 164 of the first conductive structure 160. The second blocking layer 210 is located between the two vertical portions 172 of the second conductive structure 170 and the active layer 120, surrounds the two vertical portions 172 of the second conductive structure 170, and is located on the bottom surface 173 of the horizontal portion 174 of the second conductive structure 170. The first barrier layer 200 prevents the first conductive structure 160 and the conductive layer 150 from corroding each other, and the second barrier layer 210 prevents the second conductive structure 170 and the active layer 120 from corroding each other.

In some embodiments, the antifuse structure 100 further comprises a first protection structure 220 over the conductive layer 150. The two vertical portions 162 of the first conductive structure 160 and the first barrier layer 200 surrounding portions of the two vertical portions 162 of the first conductive structure 160 are embedded in the first protective structure 220. In addition, the anti-fuse structure 100 further includes a second protection structure 230 surrounding the electrode layer 130, the conductive layer 150 and the first protection structure 220. In addition, a portion of the top surface 221 of the first protection structure 220 is substantially coplanar with the top surface 231 of the second protection structure 230; and a portion of the top surface 221 of the first protection structure 220 is higher than the top surface 231 of the second protection structure 230, wherein the portion of the top surface 221 is located below the horizontal portion 164 of the first conductive structure 160.

In some embodiments, the dielectric layer 140 is also located between the second protection structure 230 and the active layer 120. In other words, the dielectric layer 140 extends from the bottom surface 133 of the electrode layer 130 to the bottom surface 233 of the second protection structure 230. In some embodiments, the thickness T2 of the dielectric layer 140 is betweenToIn the range of (1). The thickness T2 of the dielectric layer 140 can be adjusted according to the needs of the designer. For example, a thicker dielectric layer 140 may withstand a higher applied voltage, while a thinner dielectric layer 140 may break down at the higher applied voltage.

In some embodiments, the antifuse structure 100 further includes an insulation structure 240 (also referred to as a shallow trench insulation structure) between the substrate 110 and the active layer 120. The insulating structure 240 may be made of a material including an oxide, a nitride, or a combination thereof. In addition, the vertical projection area of the active layer 120 on the substrate 110 completely overlaps the vertical projection area of the insulating structure 240 on the substrate 110. In other words, the isolation structure 240 also has a body 242 and a protrusion 244 protruding from the body 242, wherein the body 242 of the isolation structure 240 completely overlaps the body 122 of the active layer 120, and the protrusion 244 of the isolation structure 240 completely overlaps the protrusion 124 of the active layer 120. In addition, the thickness T3 of the insulating structure 240 is in the range of 335 nm to 345 nm, but not limited thereto.

Fig. 3 illustrates the active layer 120 and the electrode layer 130 of the antifuse structure 100 of fig. 1. Referring to fig. 2 and 3, the protrusion 124 of the active layer 120 has a section 123 overlapping the electrode layer 130, and the dielectric layer 140 is between the section 123 of the protrusion 124 and the electrode layer 130. Since the current flows into the region R of the electrode layer 130 overlapping the segment 123 of the protrusion 124, the current density of the region R of the electrode layer 130 is determined by the area of the segment 123 of the protrusion 124. For example, the section 123 of the small-area protrusion 124 results in a high current density in the region R of the electrode layer 130, thereby making the dielectric layer 140 relatively easy to break down. In contrast, the section 123 of the convex portion 124 having a large area causes a low current density in the region R of the electrode layer 130, thereby making it relatively difficult for the dielectric layer 140 to be broken down. However, the area of the section 123 of the protrusion 124 may not be too small to prevent the current density from reaching the upper limit to cause damage to the section 123 of the protrusion 124. In some embodiments, the area of the segment 123 of the protrusion 124 is C, the area of the protrusion 124 of the active layer 120 is D, and the ratio of C to D is in the range of 0.4 to 0.5.

In some embodiments, the end section 125 of the protrusion 124 is located in the hollowed-out region HR, the length L1 of the hollowed-out region HR is greater than the length L2 of the end section 125 of the protrusion 124, and the width W1 of the hollowed-out region HR is greater than the width W2 of the end section 125 of the protrusion 124. As such, the end section 125 of the protrusion 124 may be surrounded by the electrode layer 130. In some embodiments, the end section 125 of the protrusion 124 is arcuate in shape. In an alternative embodiment, the end section 125 of the protrusion 124 is rectangular in shape.

In some embodiments, the area of the hollow-out region HR is a, the area of the electrode layer 130 is B, and the ratio of a to (a + B) is in the range of 0.3 to 0.4. A ratio of A to (A + B) in this range ensures robustness of antifuse structure 100. Specifically, a large ratio of a to (a + B) represents a large area of the hollow region HR, so that the electrode layer 130 is flexible and fragile. In contrast, a small ratio of a to (a + B) makes it difficult for the end section 125 of the protrusion 124 to be surrounded by the electrode layer 130.

In some embodiments, the hollow area HR is rectangular in a top view. Since the rectangle includes straight lines that perpendicularly intersect with each other, the formation of the hollowed-out area HR is facilitated. In addition, since the outer edge 135 of the electrode layer 130 may also be rectangular, alignment between the hollowed region HR and the electrode layer 130 is facilitated, such that the inner edge 137 of the electrode layer 130 is substantially parallel to the outer edge 135 of the electrode layer 130.

Since the electrode layer 130 has a hollow region HR and the protrusion 124 of the active layer 120 is located in the hollow region HR, the current generated by the applied voltage can flow through the electrode layer 130 via two paths P1 and P2 before reaching the dielectric layer 140. In other words, in the event of a failure of either of the two paths, current may flow through the electrode layer 130 via the other of the two paths. As a result, the probability of failure of the antifuse structure 100 can be reduced.

It is to be understood that the connection, materials and functions of the elements described above will not be repeated and are described in detail. In the following description, only other types of active layers and electrode layers will be described.

FIG. 4 shows an active layer 120a and an electrode layer 130a of an anti-fuse structure 100 according to another embodiment of the invention. In the embodiment of fig. 4, at least one corner CR of the hollow region HR of the electrode layer 130a has an arc-shaped segment. For example, the hollow region HR of the electrode layer 130a may be a rectangle having four corners CR of arc-shaped segments. The arc-shaped section can prevent current from accumulating at the corner CR of the hollow region HR of the electrode layer 130a, thereby improving the performance of the antifuse structure 100.

FIG. 5 shows an active layer 120b and an electrode layer 130b of an anti-fuse structure 100 according to another embodiment of the invention. Refer to fig. 3 and 5. In fig. 3, a portion of the protrusion 124 is located between the sidewall 121 of the body 122 of the active layer 120 and the outer edge 135 (or the sidewall 135) of the electrode layer 130. In fig. 5, the sidewalls 121 of the body 122 of the active layer 120b are substantially aligned with the sidewalls 135 of the electrode layer 130 b.

Although the present invention has been described with reference to the above embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention.