Interposer with lattice construction and embedded conductive metal structures
A lattice structure is formed in a non-silicon interposer substrate to create large cells that are multiples of through hole pitches to act as islands for dielectric fields. Each unit cell is then filled with a dielectric material. Thereafter, holes (i.e., through holes or blind holes) are created within the dielectric material in the cells. After hole formation, a conductive metal is formed into each of the holes providing an interposer. This method can enable fine pitch processing in organic-based materials, isolates the thermal coefficient of expansion (TCE) stress from metal vias to low TCE carriers and creates a path to high volume, low costs components in panel form.
1. A method of forming an interposer, said method comprising:
creating a lattice structure having a plurality of unit cells composed of regularly repeating openings having a first dimension in a non-silicon interposer substrate;
filling an entirety of each unit cell of said plurality of unit cells with a dielectric material, wherein said dielectric material present in each unit cell has a topmost surface that is coplanar with a topmost surface of said lattice structure;
forming a plurality of holes into said topmost surface of said dielectric material present in each unit cell, wherein each hole extends downward from said topmost surface of said dielectric material, has a second dimension that is less than said first dimension and is laterally surrounded by a remaining portion of said dielectric material; and
forming a conductive structure in each hole of said plurality of holes, wherein each conductive structure has a topmost surface that is coplanar with said topmost surface of remaining portions of said dielectric material and said topmost surface of said lattice structure.
2. The method of claim 1 , wherein said non-silicon interposer substrate comprises a material having a thermal coefficient of expansion of from 0 ppm/° C. to 15 ppm/° C.
3. The method of claim 2 , wherein said material is glass.
4. The method of claim 1 , wherein each unit cell of said plurality of unit cells is a square, a rectangle, or a triangle.
5. The method of claim 1 , wherein said creating said lattice structure having said plurality of unit cells comprises machining, etching, drilling, or blasting.
6. The method of claim 1 , wherein said forming said plurality of holes into said dielectric material of each unit cell comprises drilling, wet etching, dry etching, electric discharge machining, lithography or any combination thereof.
7. The method of claim 1 , wherein at least a set of said plurality of unit cells extends only partially through said non-silicon interposer substrate, and wherein a step of removing portions of said non-silicon interposer substrate is performed after said forming said conductive structure to reveal a bottommost surface of said conductive structure.
8. The method of claim 1 , wherein said units cells are regularly repeating holes that are formed in said non-silicon interposer substrate.
9. The method of claim 1 , wherein said creating said lattice structure having said plurality of unit cells in said non-silicon interposer substrate comprises:
patterning said non-silicon interposer substrate.
10. The method of claim 1 , wherein said unit cells extend entirely through said non-silicon interposer substrate.
11. The method of claim 1 , wherein said unit cells extend partially into said non-silicon interposer substrate.
12. The method of claim 1 , wherein said dielectric material is a photo imageable dielectric material.
13. The method of claim 1 , wherein said forming said plurality of holes into said dielectric material of each unit cell comprises:
exposing said dielectric material to irradiation and developing said exposed dielectric material.
14. The method of claim 1 , wherein each hole of said plurality of holes has a smaller dimension than said unit cell.
15. The method of claim 1 , wherein each conductive structure comprises a single conductive metal or metal alloy.
16. The method of claim 1 , wherein each conductive structure comprises a multilayered stack of conductive metal or metal alloys.
17. The method of claim 1 , wherein said forming said conductive structure comprises deposition of a conductive metal or metal alloy and planarization.