Package for an implantable device
The present invention is an improved hermetic package for implantation in the human body. The implantable device of the present invention includes an eclectically non-conductive bass including electrically conductive vias through the substrate. A circuit is flip-chip bonded to a subset of the vias. A second circuit is wire bonded to another subset of the vias. Finally, a cover is bonded to the substrate such that the cover, substrate and vias form a hermetic package.
1. A biocompatible hermetic package for an implantable retinal prosthesis, comprising:
a planar base including an electrically non-conductive substrate and a plurality of electrically conductive hermetic vias through the non-conductive substrate, and biocompatible metallization on the non-conductive substrate;
an integrated circuit bonded directly to a first side of the base with conductive bumps, wherein the integrated circuit is smaller than the base defining a bonding region on the first side of the base between the integrated circuit and the edge of the base;
a circuit element electrically connected directly to the base in the bonding region;
a cover bonded to the first side of the base, the cover and the base forming a biocompatible hermetic package; and
a polymer body, including a strap, supporting the package and including suture tabs suitable to attach the package to tissue, wherein an outside of the hermetic package, including a second side of the base opposite the first side, is biocompatible ad suitable to contact tissue.
2. The hermetic package according to claim 1 , wherein said biocompatible metallization comprises thin film metallization.
3. The hermetic package of claim 1 , wherein the electrically non-conductive substrate contains ceramic.
4. The hermetic package according to claim 3 , wherein the cover contains metal.
5. The hermetic package according to claim 3 , wherein the electrically conductive vias are a metallic and ceramic paste co-fired with the electrically non-conductive substrate to form a hermetic seal.
6. The hermetic package according to claim 3 , wherein the cover is brazed to the base.
7. The hermetic package according to claim 2 , wherein the patterned thin film metallization is a multiple layer thin film metallization and the integrated circuit and the circuit element are bonded to the patterned thin film metallization.
8. The hermetic package according to claim 7 , wherein the multiple layer thin film metallization is chosen to withstand braze temperatures.
9. The hermetic package according to claim 8 , wherein the multiple layer thin film metallization comprises more than one of the metals including titanium, tantalum, gold, palladium, platinum or layers or alloys thereof.
10. The hermetic package according to claim 1 , further comprising a flexible circuit bump bonded to the base.
11. The hermetic package according to claim 1 , further comprising
metal traces deposited on the electrically non-conductive substrate and in contact with the electrically conductive vias; and
a flexible circuit attached to the metal traces.
12. The hermetic package according to claim 11 , wherein the flexible circuit is an electrode array suitable for stimulating tissue.
13. The hermetic package according to claim 1 , further comprising a polymer underfill under the integrated circuit.
14. The hermetic package according to claim 1 , wherein the conductive bumps contain at least one conductive polymer.
15. The hermetic package according to claim 1 , wherein the conductive bumps contain at least one conductive epoxy or polyimide.
16. The hermetic package according to claim 1 , wherein conductive bumps bonding the integrated circuit to the base are filled with one or more metals like silver, platinum, iridium, titanium, platinum alloys, iridium alloys, or titanium alloys or mixtures thereof.
17. The hermetic package according to claim 16 , wherein the metal or metal alloys are in dust, flake or powder form.
18. The hermetic package according to claim 1 , further comprising a getter.
19. The hermetic package according to claim 18 , wherein the getter is placed on the inside of the cover.