Micro-miniature implantable coated device
An implantable micro-miniature device is disclosed. The device comprises a thin hermetic insulating coating and at least one thin polymer or metal secondary coating over the hermetic insulating layer in order to protect the insulating layer from the erosive action of body fluids or the like. In one embodiment the insulating layer is ion beam assisted deposited (IBAD) alumina and the secondary coating is a parylene polymer. The device may be a small electronic device such as a silicon integrated circuit chip. The thickness of the insulating layer may be ten microns or less and the thickness of the secondary layer may be between about 0.1 and about 15 microns.
1. A method of making a micro-miniature implantable device, comprising:
providing a micro-miniature device including contact pads;
coating a least a major portion of said device, excluding a portion of the contact pads, with a thin electrically insulating conformal patterned inorganic hermetic layer about 10 microns thick, having an outside surface; and
limiting oxygen degradation of said electrically insulating conformal patterned inorganic hermetic layer by coating only said outside surface of said thin insulating conformal inorganic hermetic layer, and not the contact pads, with a conformal patterned metal layer between 0.3 and 7 microns thick;
attaching wires to the contact pad portion excluded from coating, wherein the wires pass straight through the inorganic hermetic layer and the conformal patterned metal layer; and
wherein the thin electrically insulating conformal inorganic hermetic patterned layer and the contact pads form a hermetic seal around the micro-miniature device.
2. The method of making a micro-miniature implantable device of claim 1 wherein said step of coating at least a major portion of said device with a thin insulating conformal inorganic hermetic layer is coating by IBAD.
3. The method of making a micro-miniature implantable device of claim 1 wherein at least a major portion of said device is coated with a thin insulating conformal inorganic hermetic layer by microwave enhanced chemical vapor deposition.
4. The method of making a micro-miniature implantable device of claim 1 wherein said thin insulating conformal inorganic hermetic layer is coated with a metal by chemical vapor deposition.
5. The method of making a micro-miniature implantable device of claim 1 wherein the micro-miniature implantable device is a nerve stimulator including a visual prosthesis, cochlear prosthesis, deep brain stimulator, spinal cord stimulator, or functional electrical stimulator for motor control.
6. The method of making a micro-miniature implantable device of claim 1 , wherein the metal layer is selected from the group consisting of gold, titanium, platinum, iridium and mixtures thereof.