Tiled construction of layered materials
View Patent ↗A method is described for combining the diverse strengths of two materials in a tiled film construction. The first material provides a foundation of intersecting grid lines on a substrate and the second material is contained within the grid lines and has a valued property for a particular application. In a preferred embodiment, a tiled dielectric layer has improved low-k dielectric performance while avoiding film stress problems that can lead to delamination or cracking. CTE mismatch is overcome at the cost of an additional masking step. This tiling method and layered binary construction enable Cytop to be used as a high performance low-k dielectric on most substrates including semiconductor wafers and copper panels or foils.
1. A tiled layer construction formed on a substrate having a substantially planar substrate surface, the tiled layer construction comprising:
a first material having a first thermal coefficient of expansion forming intersecting grid lines on the substrate surface, the grid lines covering respective first portions of the substrate surface and defining second portions of the substrate surface, each respective second portion completely outlined by the grid lines; and,
a second material having a second thermal coefficient of expansion disposed on the respective second portions of the substrate and bounded by the respective grid lines.
2. The tiled layer construction of claim 1 , wherein the tiled layer construction is repeated to form multiple layers of the tiled construction on the substrate.
3. The tiled layer construction of claim 2 , further comprising embedded conductors having the tiled layer construction in one or more of the multiple layers.
4. The tiled layer construction of claim 3 , wherein the multiple layers of the tiled construction and the embedded conductors in the one or more layers of tiled construction form an interconnection circuit.
5. The tiled layer construction of claim 1 , wherein the first material is compatible with the substrate with respect to adhesion.
6. The tiled layer construction of claim 1 , wherein the first material is compatible with the substrate with respect to the first thermal coefficient of expansion.
7. The tiled layer construction of claim 1 , further comprising the substrate, the substrate comprising copper.
8. The tiled layer construction of claim 1 , further comprising the substrate, the substrate comprising a semiconductor wafer.
9. The tiled layer construction of claim 1 , wherein the second material is-comprises an amorphous fluoropolymer.
10. The tiled layer construction of claim 1 , wherein the first and second materials have similar photolithographic properties or similar physical properties for ease of patterning the tiled layer construction in a single patterning step.
11. The tiled layer construction of claim 1 wherein the grid lines formed from the first material provide structural support for subsequent planarization of the tiled layer using a chemical-mechanical-polishing process.
12. The tiled layer construction of claim 1 wherein the first and second materials comprise respective different dielectric materials.
13. The tiled layer construction of claim 1 wherein the grid lines include a first plurality of parallel grid lines oriented in a first direction along the substrate surface and a second plurality of parallel grid lines oriented in a second direction along the substrate surface such that the first plurality of parallel grid lines intersect the second plurality of parallel grid lines.
14. The tiled layer construction of claim 13 wherein the first direction is orthogonal to the second direction.