Package for an implantable neural stimulation device
An implantable device, including a first electrically non-conductive substrate; a plurality of electrically conductive vias through the first electrically non-conductive substrate; a flip-chip multiplexer circuit attached to the electrically non-conductive substrate using conductive bumps and electrically connected to at least a subset of the plurality of electrically conductive vias; a flip-chip driver circuit attached to the flip-chip multiplexer circuit using conductive bumps; a second electrically non-conductive substrate attached to the flip-chip driver circuit using conductive bumps; discrete passives attached to the second electrically non-conductive substrate; and a cover bonded to the first electrically non-conductive substrate, the cover, the first electrically non-conductive substrate and the electrically conductive vias forming a hermetic package.
1. An implantable device suitable to be attached to a sclera, comprising:
an electrically non-conductive substrate;
a plurality of electrically conductive vias through the electrically non-conductive substrate;
conductive traces deposited on the electrically non-conductive substrate, the electrically non-conductive substrate, electrically conductive vias and conductive traces forming a base;
a circuit attached to the base;
a cover having a curved semispherical profile across its entire width bonded to the base, the cover and the base forming a hermetic package.
2. The implantable device according to claim 1 , wherein the cover has convex in profile.
3. The implantable device according to claim 1 , wherein the cover has concave in profile.
4. The implantable device according to claim 1 , wherein the circuit is a flip-chip circuit.
5. The implantable device according to claim 4 , further comprising a stack chip circuit bonded to the flip chip circuit and wire bonded to the base.
6. The implantable device according to claim 5 , further comprising a second electrically non-conductive substrate bonded to the stack chip circuit and wire bonded to the base; and
discrete passives attached to the second electrically non-conductive substrate.
7. The implantable device according to claim 1 , wherein the electrically conductive vias are a metallic and ceramic paste co-fired with the electrically non-conductive substrate to form a hermetic seal.
8. The implantable device according to claim 1 , wherein the cover is brazed to the base.
9. The implantable device according to claim 8 , further comprising a braze stop on said first electrical nonconductive substrate and along a periphery of said electrically non-conductive substrate surrounding the plurality of electrically conductive vias and separating a braze joint from said plurality of electrically conductive vias.
10. The implantable device according to claim 1 , wherein the conductive traces are metal traces.
11. The implantable device according to claim 10 , wherein the metal traces are chosen to withstand braze temperatures.
12. The implantable device according to claim 11 , wherein the metal traces comprise one or more of the metals titanium, tantalum, gold, palladium, platinum or layers or alloys thereof.
13. The implantable device according to claim 1 , further comprising a flexible circuit bump bonded to the base.
14. The implantable device according to claim 13 , wherein the flexible circuit is an electrode array suitable for stimulating tissue.
15. The implantable device according to claim 4 , further comprising a polymer underfill under the flip-chip circuit.