Method of forming a crack stop laser fuse with fixed passivation layer coverage
View Patent ↗A crack stop void is formed in a low-k dielectric or silicon oxide layer between adjacent fuse structures for preventing propagation of cracks between the adjacent fuse structures during a fuse blow operation. The passivation layer is fixed in place by using an etch stop shape of conducting material which is formed simultaneously with the formation of the interconnect structure. This produces a reliable and repeatable fuse structure that has controllable passivation layer over the fuse structure that is easily manufactured.
1. A method comprising the steps of:
providing a substrate including a plurality of fuse structures formed thereupon;
forming a dielectric layer over the fuse structures;
forming a conductor layer over an interconnect structure and a disposable conductive hard etch stop shape over each of the fuse structures wherein the etch stop controls the intermediate dielectric layer above each ones of the fuse structures; and
forming a material-free region between adjacent ones of said fuse structure.
2. The method of claim 1 , wherein said step of forming a material-free region includes removing a portion of the dielectric layer in which said adjacent fuse structures are formed.
3. The method of claim 1 , wherein said material-free region comprises a fluid or vacuum.
4. The method of claim 1 , wherein said interconnect structure comprises a conductive transfer pad, said conductive transfer pad coupled to a wiring pad.
5. The method of claim 1 which includes a step of removing the hard etch shapes prior to a fuse blow operation.
6. The method of claim 2 , wherein said step of removing a portion of said dielectric layer occurs during an over-etch of said portion of said conductor layer.
7. The method of claim 2 , wherein said dielectric layer comprises a low-k dielectric material.
8. The method of claim 2 , wherein said dielectric layer comprises a silicon oxide dielectric material.
9. A method comprising the steps of:
providing a substrate including a plurality of fuse structures formed in a first dielectric layer;
forming at least a second dielectric layer over said plurality of fuse structures;
forming a conductor layer on said second dielectric layer;
patterning the conductor layer to simultaneously form an interconnect structure, and a conductive hard etch stop shape over each ones of the fuse structures in order accurately position an intermediate passivation layer above the fuse structures;
forming an opening in said at least second dielectric layer between adjacent ones of said fuse structures to create a void wherein the void prevents propagation of cracks between said adjacent fuse structures during a fuse blow operation, and
removing the hard etch stop shape prior to a fuse blow operation.
10. The method of claim 9 , wherein said void extends into said first dielectric layer.
11. The method of claim 9 , wherein said first dielectric layer comprises a low-k dielectric material.
12. The method of claim 9 , wherein the step of patterning includes forming a second interconnect structure.
13. The method of claim 9 , wherein said first interconnect structure comprises one of a conductive transfer pad, a via, a pad connect structure or a BEOL passive device.
14. The method of claim 9 , wherein said step of forming said at least second dielectric layer comprises:
forming a first silicon nitride layer;
forming a silicon oxide layer on said first silicon nitride layer; and
forming a second silicon nitride layer on said silicon oxide layer.
15. The method of claim 9 , wherein said step of forming said opening in said at least second dielectric layer comprises:
forming a photoresist layer on said at least second dielectric layer;
exposing and developing said photoresist layer; and
etching exposed portions of said at least second dielectric layer to form said opening.
16. The method of claim 9 , wherein said step of patterning said conductor layer comprises:
forming a photoresist layer on said conductor layer;
exposing and developing said photoresist layer; and
removing an exposed portion of said conductor layer, wherein a remaining portion of the conductor layer forms said first interconnect structure and the hard edge stop.
17. The method of claim 10 , wherein said void extends to a depth below a lower surface of said adjacent fuse structures.
18. The method of claim 11 , wherein said low-k dielectric material is selected from one of hydrogen silsesquioxane polymer (HSQ), methyl silsesquioxane polymer (MSQ), polyphenylene oligomer, SiO x (CH3) y , and fluorinated TEOS (FTEOS) and fluorinated silicon glass (FSG).
19. The method of claim 12 , wherein said second interconnect structure comprises a wiring pad.
20. The method of claim 16 , wherein the void comprises a fluid or vacuum.