MEMS device and method for delivery of therapeutic agents

1. A method of manufacturing an implantable pump, the method comprising:

providing an upper layer comprising a dome structure for housing a drug chamber and a cannula in fluid communication with the drug chamber;

providing a middle deflection layer adjacent the drug chamber;

providing a bottom layer comprising electrolysis electrodes; and

bonding the upper layer, middle deflection layer, and bottom layer along a common peripheral exterior edge of the upper and middle deflection layers to form the pump.

2. The method of claim 1 , further comprising the step of forming the drug chamber between the upper layer and the middle deflection layer after thermal bonding.

3. The method of claim 1 , further comprising the step of forming the electrolysis chamber between the middle deflection layer and the bottom layer after thermal bonding.

4. The method of claim 1 , further comprising providing at least one fill port in fluid communication with at least one of the electrolysis chamber or the drug chamber.

5. The method of claim 1 , wherein at least one of the upper layer, the middle layer, and the bottom layer is formed by a lithographic process.

6. The method of claim 5 , wherein the lithographic process comprises the steps of:

sequentially layering layers of a construction material and a photoresist material;

etching at least one of the construction material and a photoresist material to provide a required shape, and

subjecting the layers to photoresist stripper, thereby removing the photoresist material and leaving the shaped construction material in place.

7. The method of claim 1 , wherein at least one of the upper layer, the middle layer, and the bottom layer is formed by a molding process.

8. The method of claim 1 , wherein at least one of the upper layer, the middle layer, and the bottom layer comprises or consists essentially of parylene.

9. The method of claim 1 , wherein the dome structure is manufactured by the steps of:

providing a mold having a domed shape;

conformably coating a layer of material on the mold; and

after the material has set, peeling the resulting dome structure from the mold.

10. The method of claim 1 , wherein the cannula is manufactured according to steps comprising:

coating a first photoresist layer onto a silicon substrate as a sacrificial layer;

depositing a first parylene layer onto the photoresist layer to form a bottom surface of the cannula;

creating a through hole in the first parylene layer;

coating a second photoresist layer over the first parylene layer;

depositing a second parylene layer on the second photoresist layer, the second parylene layer forming a top and a side of the cannula;

patterning the first and second parylene layers to form a cannula shape; and

removing the first and second photoresist layers, thereby leaving the formed cannula.

11. The method of claim 10 , wherein the patterning step comprises reactive-ion etching with a photoresist material used as an etching mask.

12. The method of claim 10 , wherein the patterning step comprises patterning the first parylene layer and second parylene layer in a RIE oxygen plasma using a photoresist mask.

13. The method of claim 10 , wherein at least one of the coating steps comprises spin-coating.

14. The method of claim 1 , further comprising integrating at least one of a check valve, a flow sensor, a pressure sensor, or a chemical sensor into the pump.

15. The method of claim 11 , wherein the middle deflection layer comprises a corrugated diaphragm.

16. The method of claim 15 , wherein the corrugated diaphragm is formed according to steps comprising:

coating a first photoresist layer onto a silicon substrate;

etching the silicon substrate using the first photoresist layer as a mask;

removing the first photoresist layer, thereby leaving a mold formed by the silicon substrate;

coating a parylene layer on the silicon substrate; and

after the parylene layer has set, releasing the parylene layer from the silicon substrate thereby forming the corrugated diaphragm.

17. The method of claim 1 , wherein the middle deflection layer comprises a bellows structure.

18. The method of claim 17 , wherein the bellows structure is formed according to steps comprising:

coating a first photoresist layer onto a silicon substrate as a sacrificial layer;

depositing a first parylene layer onto the first photoresist layer to form a first layer of the bellows structure;

coating a second photoresist layer over the first parylene layer;

opening a bonding area in the second photoresist layer by lithography;

depositing a second parylene layer onto the second photoresist layer to form a second layer of the bellows structure, wherein the second parylene layer bonds to the first parylene layer at the bonding area;

patterning the first and second parylene layers;

coating a third photoresist layer onto the second parylene layer;

depositing a third parylene layer onto the third photoresist layer to form a third layer of the bellows structure;

patterning the bellows structure by etching through the second and third parylene layers; and

removing the photoresist layers by subjection to photoresist stripper, thereby leaving the parylene bellows structure.

19. The method of claim 1 , wherein the bottom layer is formed according to steps comprising:

coating a first photoresist layer onto a silicon substrate as a sacrificial layer;

depositing a first parylene layer onto the first photoresist layer to form a first layer of the bottom layer;

depositing a metal electrode layer on the first parylene layer;

depositing a second parylene layer over the metal electrode layer;

etching the second parylene layers to expose at least a portion of the electrode; and

removing the photoresist layers by subjection to photoresist stripper, thereby leaving the bottom layer.

20. The method of claim 19 , wherein the metal electrode layer is deposited by E-beam evaporation and patterned by life-off process or etching process.

21. The method of claim 19 , wherein the etching step comprises RIE oxygen plasma etching masked by a photoresist mask.

22. The method of claim 19 , further comprising annealing the bottom layer to improve the adhesion between the parylene layers and metal electrode layer.

23. The method of claim 19 , wherein the metal electrode layer comprises or consists essentially of platinum.

24. The method of claim 1 , further comprising a substantially rigid spacer comprising a refill hole.