Method of forming a substantially closed void
View Patent ↗To form a substantially closed void between two structures on a substrate, a flowable liquid dielectric material is deposited to fill partially the space between the structures, and a surface is placed to bridge and substantially close the space between the structures. The substrate is then inverted whilst maintaining the bridge and the deposited material is allowed to flow down to be substantially supported by the surface. The material is set in its substantially supported position, and the surface is removed.
1. A method of forming a substantially closed void between two structures on a substrate, the two structures defining a space there between, the space including an opening opposite a closed bottom surface, said method comprising:
(a) depositing a flowable liquid dielectric material to fill partially the space between the structures;
(b) placing a surface to bridge and substantially close the opening of the space between the structures;
(c) inverting the substrate whilst maintaining the bridge and allowing the deposited material to flow down to be substantially supported by the surface, wherein a closed void is formed between the material in its substantially supported position and the closed bottom surface of the space between the structures;
(d) setting the material in its substantially supported position; and
(e) removing the surface.
2. A method as claimed in claim 1 wherein the surface is flat.
3. A method as claimed in claim 1 wherein the surface is non-wetting for the flowable material.
4. A method as claimed in claim 1 wherein the material is set by temperature, IR radiation, UV radiation, RF radiation or a chemical reaction or a combination thereof.
5. A method as claimed in claim 4 wherein the material is set, at least in part, by radiation and the surface is transparent to that radiation.
6. A method as claimed in claim 1 wherein the surface is formed on a substantially rigid body.
7. A method as claimed in claim 6 wherein the surface is formed on sapphire.
8. A method as claimed in claim 1 wherein the structures are a pair of metal lines or a pair of walls of a trench or cavity or combinations thereof.
9. A method as claimed in claim 2 wherein the surface is non-wetting for the flowable material.
10. A method as claimed in claim 1 wherein the material is set, at least in part, by radiation and the surface is transparent to that radiation.
11. A method as claimed in claim 2 wherein the surface is formed on a substantially rigid body.
12. A method as claimed in claim 2 wherein the surface is formed on sapphire.
13. A method as claimed in claim 9 wherein the surface is formed on a substantially rigid body.
14. A method as claimed in claim 1 , wherein the deposited material flows down under force of gravity to be substantially supported by the surface.
15. A method as claimed in claim 1 , wherein the closed void is under vacuum.
16. A method as claimed in claim 14 , wherein the closed void is under vacuum.