Semiconductor device having fuse element and method of cutting fuse element

Abstract

A semiconductor device includes a lower electrode, an upper electrode, and a fuse element that connects the lower electrode and the upper electrode. The height of the fuse element is greater than the depth of focus of a laser beam to be irradiated. The diameter of the fuse element is smaller than the diffraction limit of the laser beam. Thus, in the present invention, a vertically long fuse element is used, so that it is possible to efficiently absorb the energy of the laser beam. It is possible to cut the fuse element by using an optical system having a small depth of focus, so that the damage imposed on a member located above or below the fuse element is very small. As a result, the fuse element can be without destructing the passivation film.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of this invention will become more apparent by reference to the following detailed description of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic cross section of the structure of a fuse element included in a semiconductor device according to a preferred embodiment of the present invention;

FIG. 2 is a circuit diagram of an example of a program circuit using the fuse element shown in FIG. 1;

FIG. 3 is a schematic diagram for explaining a method of cutting the fuse element shown in FIG. 1 with a laser beam;

FIG. 4 is a schematic cross section of a fuse element that has been cut;

FIGS. 5A and 5B are explanatory diagrams of an influence of dust adhering to a passivation film, where FIG. 5A shows an example in which an objective lens having a relatively small numerical aperture is used, and FIG. 5B shows an example in which an objective lens having a relatively large numerical aperture is used;

FIG. 6 is a schematic cross section of an example in which another wiring is arranged below the fuse element;

FIG. 7 is a schematic cross section of an example in which another wiring is arranged above the fuse element;

FIG. 8 is a schematic cross section of an example in which a plurality of fuse elements are arranged adjacent to one another;

FIG. 9 is a schematic diagram showing a state in which a fuse element different from a fuse element to be cut is irradiated with a laser beam;

FIG. 10 is a schematic diagram showing a state in which several fuse elements are cut without substantially destructing the passivation film;

FIG. 11 is a process diagram showing a process of forming dielectric films on lower electrode that is a part of the manufacturing process of the semiconductor device according to the embodiment of the present invention;

FIG. 12 is a process diagram showing a process of forming a photoresist that is a part of the manufacturing process of the semiconductor device according to the embodiment of the present invention;

FIG. 13 is a process diagram showing a process of forming through-holes that is a part of the manufacturing process of the semiconductor device according to the embodiment of the present invention;

FIGS. 14 and 15 are process diagrams showing a process of forming fuse element that is a part of the manufacturing process of the semiconductor device according to the embodiment of the present invention;

FIG. 16 is a process diagram showing another process of forming fuse element by using a film formation method excellent in coverage; and

FIG. 17 is a process diagram showing another process of forming fuse element by using a film formation method low in coverage.

Claims

1. A semiconductor device, comprising: a lower electrode arranged in a first wiring layer;an upper electrode arranged in a second wiring layer located higher than the first wiring layer; anda fuse element that connects the lower electrode and the upper electrode, a height of the fuse element being at least three times greater than a diameter of the fuse element.

2. The semiconductor device as claimed in claim 1, wherein the height of the fuse element is 1 μm or more.

3. The semiconductor device as claimed in claim 1, wherein the diameter of the fuse element is 300 nm or less.

4. The semiconductor device as claimed in claim 1, wherein a plurality of fuse elements are provided, and a distance between adjacent fuse elements is smaller than the height of the fuse element.

5. The semiconductor device as claimed in claim 1, wherein the fuse element has a tubular shape having a hollow portion.

6. The semiconductor device as claimed in claim 5, wherein the fuse element includes a first tubular portion located on the lower electrode side and a second tubular portion located on the upper electrode side, and a diameter at a lower end of the second tubular portion is smaller than a diameter at an upper end of the first tubular portion.

7. The semiconductor device as claimed in claim 6, wherein an insulating material that constitutes a layer in which the first tubular portion is formed and an insulating material that constitutes a layer in which the second tubular portion is formed are different.

8. The semiconductor device as claimed in claim 1, further comprising a wiring that is arranged in a third wiring layer located lower than the first wiring layer and is located below the fuse element.

9. The semiconductor device as claimed in claim 1, further comprising a wiring that is arranged in a fourth wiring layer located higher than the second wiring layer and is located above the fuse element.

10. A semiconductor device, comprising: a lower electrode arranged in a first wiring layer;an upper electrode arranged in a second wiring layer located higher than the first wiring layer; anda plurality of fuse elements that connect the lower electrode and the upper electrode, a distance between adjacent fuse elements being smaller than a height of the fuse element.

11. The semiconductor device as claimed in claim 10, wherein the fuse elements have a tubular shape having a hollow portion.

12. A semiconductor device, comprising: a lower electrode arranged in a first wiring layer;an upper electrode arranged in a second wiring layer located higher than the first wiring layer; anda fuse element that connects the lower electrode and the upper electrode, a height of the fuse element being greater than a depth of focus of a laser beam to be irradiated.

13. The semiconductor device as claimed in claim 12, wherein a diameter of the fuse element is smaller than a diffraction limit of the laser beam.

14. The semiconductor device as claimed in claim 12, wherein the fuse element is has a tubular shape having a hollow portion.

15. A semiconductor device, comprising: a plurality of fuse elements that can be cut by irradiation with a laser beam; anda passivation film, which is formed seamless and continuous, arranged in an area that covers at least the fuse elements, whereinat least one of the fuse elements is cut by laser beam irradiation.

16. The semiconductor device as claimed in claim 15, wherein the fuse element is has a tubular shape having a hollow portion.

17. A method of cutting a fuse element employed in a semiconductor device, comprising: step for providing the semiconductor device; andstep for irradiating a laser beam to the fuse element, the laser beam has a depth of focus smaller than a height of the fuse element, and has a diffraction limit greater than a diameter of the fuse element.

18. The method of cutting a fuse element as claimed in claim 17, wherein the depth of focus is half or less than the height of the fuse element.

19. The method of cutting a fuse element as claimed in claim 17, wherein the fuse element is cut without substantially destructing a passivation film located at an upper portion of the fuse element.

20. The method of cutting a fuse element as claimed in claim 19, wherein the laser beam is irradiated by providing liquid between the passivation film and an objective lens that converges the laser beam.

21. A method of cutting a tubular fuse element having a hollow portion employed in a semiconductor device, comprising: step for providing the semiconductor device; andstep for irradiating a laser beam to the tubular fuse element from an axial direction.

22. The method of cutting a tubular fuse element as claimed in claim 21, wherein the fuse element is cut without substantially destructing a passivation film located at an upper portion of the fuse element.

23. The method of cutting a tubular fuse element as claimed in claim 22, wherein the laser beam is irradiated by providing liquid between the passivation film and an objective lens that converges the laser beam.