Semiconductor device having a fuse element
View Patent ↗A corrosion resistant semiconductor device includes fuse elements that can be cut by laser light. An upper portion of the fuse elements is covered with a porous insulating film so that, when laser light irradiated from a rear surface of a semiconductor substrate is collected at selected fuse elements, the fuse elements generate heat, expand, and rupture. A metal lattice having a plurality of windows is disposed over the fuse elements to permit rapid expansion of the fuse elements when irradiated with the laser light. Alternatively, a metal array having a plurality of independent light-shielding portions may be disposed over the fuse elements to prevent the laser light from adversely affecting circuitry on the front surface side of the semiconductor device.
1. A semiconductor device having a fuse element, comprising:
a semiconductor substrate;
a field insulating film formed on a front surface of the semiconductor substrate;
a fuse element formed on the field insulating film;
an intermediate insulating film completely covering a side surface and a top surface of the fuse element;
a metal lattice formed on the intermediate insulating film and covering the fuse element, the metal lattice having a plurality of windows each of which has four sides;
an interlayer film formed around the metal lattice;
an opening region formed in the interlayer film and having a side surface and a bottom portion overlying a top surface of the metal lattice; and
a silicon nitride film covering the side surface and the bottom portion of the opening region.
2. A semiconductor device according to claim 1 , wherein the silicon nitride film is in contact with the top surface of the metal lattice.
3. A semiconductor device according to claim 1 , further comprising a porous insulating film formed between the silicon nitride film and the intermediate insulating film so that the porous insulating film surrounds the metal lattice.
4. A semiconductor device according to claim 1 , wherein the silicon nitride film has a uniform thickness on the interlayer film and on the side surface and the bottom portion of the opening region.
5. A semiconductor device according to claim 1 , wherein each of the windows has a rectangular shape having opposed longer sides that are shorter than a wavelength of laser light to be irradiated on a rear surface of the semiconductor substrate to cut the fuse element.
6. A semiconductor device according to claim 5 , wherein the rectangular windows are densely arranged above the fuse element.
7. A semiconductor device having a fuse element, comprising:
a semiconductor substrate;
a field insulating film formed on a front surface of the semiconductor substrate;
a fuse element formed on the field insulating film;
an intermediate insulating film covering a side surface and a top surface of the fuse element;
a metal array formed on the intermediate insulating film and covering the fuse element, the metal array having a plurality of independent light-shielding portions each having a rectangular shape;
an interlayer film formed around the metal array;
an opening region formed in the interlayer film and having a side surface and a bottom portion overlying a top surface of the metal array; and
a silicon nitride film covering the side surface and the bottom portion of the opening region.
8. A semiconductor device according to claim 7 , wherein the plurality of independent light-shielding portions are two-dimensionally arranged with an interval therebetween that is shorter than a wavelength of laser light to be irradiated on a rear surface of the semiconductor substrate to cut the fuse element.
9. A semiconductor device according to claim 8 , wherein each of the plurality of light-shielding portions is in a shape that allows the plurality of light-shielding portions to be two-dimensionally repeatedly arranged.
10. A semiconductor device according to claim 8 , wherein the plurality of light-shielding portions are in shapes that allow the plurality of light-shielding portions to be two-dimensionally repeatedly arranged by combining a predetermined number of the plurality of light-shielding portions.
11. A semiconductor integrated circuit device, comprising:
a semiconductor substrate having front and rear surfaces;
a field insulating film disposed on the front surface of the semiconductor substrate;
fuse elements disposed in spaced-apart relationship on the field insulating film, each fuse element having two opposite end portions interconnected by a middle portion;
an intermediate insulating film formed on the fuse elements and completely covering top and side surfaces of the fuse elements;
a metal lattice disposed over the intermediate insulating film and over the middle portions of the fuse elements, the metal lattice having a plurality of windows partly or completely overlying the middle portions of the fuse elements;
an interlayer film formed around the metal lattice and in the windows, the interlayer film having a recessed opening overlying the metal lattice; and
a silicon nitride film formed on the interlayer film and on the entire surface of the recessed opening.
12. A semiconductor integrated circuit device according to claim 11 ; wherein some of the windows partly overlie the middle portions and others completely overlie the middle portions of the fuse elements.
13. A semiconductor integrated circuit device according to claim 12 ; wherein the windows have a rectangular shape.
14. A semiconductor integrated circuit device according to claim 13 ; wherein the windows have a square shape.
15. A semiconductror integrated circuit device according to claim 13 ; wherein the rectangularly-shaped windows have opposed longer sides and opposed shorter sides, the longer sides being shorter in length than a wavelength of laser light to be irradiated on the rear surface of the semiconductor surface to cut the middle portion of selected fuse elements.
16. A semiconductror integrated circuit device according to claim 13 ; wherein the interval betwen adjacent longer sides of each two adjacent windows overlying the middle portions of the fuse elemnets is ½ to 1/20 the length of the longer sides.
17. A semiconductror integrated circuit device according to claim 13 ; wherein the interval betwen adjacent longer sides of each two adjacent windows is ½ to 1/10 the length of the longer sides.
18. A semiconductror integrated circuit device according to claim 11 ; wherein the metal lattice is disposed over the middle portions of the fuse elements but not over the end portions of the fuse elements.
19. A semiconductror integrated circuit device according to claim 11 ; wherein the silicon nitride film has a uniform thickness on the interlayer film and on the recesed opening.