Laser chalcogenide phase change device
View Patent ↗A laser activated phase change device for use in an integrated circuit comprises a chalcogenide fuse configured to connect a first patterned metal line and a second patterned metal line and positioned between an inter layer dielectric and an over fuse dielectric. The fuse interconnects active semiconductor elements manufactured on a substrate. A method for activating the laser activated phase change device includes selecting a laser condition of a laser based on characteristics of the fuse and programming a phase-change of the fuse with the laser by direct photon absorption until a threshold transition temperature is met.
1. A laser activated phase change device for use in a semiconductor integrated circuit, the device comprising:
a fuse made of a phase change material and connected between a first metal line and a second metal line, each metal line lying either on or within an inter layer dielectric such that bottom surfaces of the first and second metal lines lie at substantially a same height with respect to a substrate, the fuse having a bottom surface and an opposing top surface and positioned such that at least a portion of the bottom surface is in contact with the inter layer dielectric either directly or through only an adhesive layer at substantially the same height as or at a height higher than the bottom surfaces of the first and second metal lines and such that an over fuse dielectric overlies at least a portion of the top surface, the over fuse dielectric having a thickness such that the over fuse dielectric is transmissive to wavelengths generated by a laser sufficient to program a phase change of the fuse using direct photon absorption and wherein the fuse interconnects active semiconductor elements manufactured on the substrate.
2. The device of claim 1 , wherein the fuse is configured to completely fill a gap between the first and second metal lines.
3. The device of claim 1 , wherein ends of the first and second metal lines form a gap therebetween and the fuse is layered on respective portions of the ends of the first and second metal lines to span the gap.
4. The device of claim 3 further comprising:
an adhesive layer between the fuse and the respective portions of the ends of the first and second metal lines.
5. The device of claim 3 , wherein the fuse fills at least a portion of the gap in addition to spanning the gap.
6. The device of claim 1 , wherein the first and second metal lines are located within the inter layer dielectric, the device further comprising:
a first interconnect via vertically extending from the first metal line in a direction away from the substrate; and
a second interconnect via vertically extending from the second metal line in the direction away from the substrate, the fuse connected between the first and second metal lines by spanning a gap between the first and second interconnect vias.
7. The device of claim 1 , further comprising:
a laser fuse bank comprising a plurality of fuses, the fuse being one of the plurality of fuses and the fuse spaced from adjacent fuses by a distance of less than one-half a width of a spot size of the laser.
8. The device of claim 7 wherein each of the plurality of fuses is made of the phase change material and is connected between a respective first metal line and a respective second metal line, each metal line lying either on or within the inter layer dielectric such that bottom surfaces of the metal lines lie at substantially the same height with respect to the substrate, each fuse having a respective bottom surface and a respective opposing top surface and positioned such that at least a portion of each bottom surface is in contact with the inter layer dielectric either directly or through only a respective adhesive layer at substantially the same height as or at a height higher than the bottom surfaces of the metal lines and such that the over fuse dielectric overlies at least portions of each top surface and wherein each fuse of the plurality of fuses interconnects active semiconductor elements manufactured on the substrate.
9. The device of claim 1 wherein the fuse reversably electrically interconnects the active semiconductor elements manufactured on the substrate.
10. The device of claim 1 wherein the over fuse dielectric is silicon dioxide; and wherein the thickness of the over fuse dielectric overlying the top surface of the fuse is less than approximately 10 micrometers.
11. The device of claim 1 wherein the active semiconductor elements manufactured on the substrate comprise a first active semiconductor element and a second active semiconductor element, the first active semiconductor element connected to the fuse through the first metal line and the second active semiconductor element connected to the fuse through the second metal line.