Method of forming a mold and molding a micro-device

1. A method of forming a mold for a micro-device including an array of microfeatures, comprising:

providing a master having a surface contour which includes skin penetration features;

covering the surface contour with a layer of material having a thickness of about 0.01-0.2 inches;

removing the master from the layer of material to form a negative image of the master in the layer of material wherein the negative image is fillable by a flowable process;

filling the negative image fluidically with a flowable powdered metallic materiel to form a device having substantially the same features as the master; and

sintering the powdered metallic material to form the micro-device.

2. The method of claim 1 , further comprising, coating the master with a release film, before the covering of the surface contour, to facilitate removal of the master.

3. The method of claim 1 , further comprising, etching to remove the master.

4. The method of claim 3 , wherein the etchant is hydroxide.

5. The method of claim 1 , wherein the layer of material is a metal.

6. The method of claim 1 , wherein the layer of material is nickel.

7. The method of claim 1 , wherein the master is sacrificed during its removal.

8. The method of claim 1 , Wherein the negative image has at least one structural feature of about 5 microns to about 250 microns in one dimension.

9. The method of claim 1 , wherein the negative image defines recesses having a depth from its surface of about 5 microns to about 250 microns.

10. The method of claim 9 , wherein the recesses are arranged in an array of uniformly spaced rows and columns to provide a density of about 1 to about 100 of the recess per mm2.

11. The method of claim 1 , wherein the master is formed from silicon.

12. The method of claim 1 , further comprising:

individually forming portions of the master from silicon; and

connecting the portions into a complete master.

13. The method of claim 1 , wherein the layer of material is formed via sintering.

14. A method of forming a device including a plurality of micron or sub-micron sized features, the method comprising:

providing a master having a surface contour defining skin penetration features;

coating the surface contour of the master with at least one layer of material having a thickness of about 0.01-0.2 inches;

removing the master from the layer of material to form a negative image of the surface contour in the layer of material;

forming a mold insert from the negative image; and

performing injection molding to fill the negative image fluidicaily to form a device having substantially the same features as the master.

15. The method of claim 14 , wherein the injection molding is done at a vacuum.

16. The method of claim 14 , further comprising drilling holes in the features of the device to form hollow micro-needles.

17. The method of claim 14 , wherein the layer of material is at about 0.07 inches thick.

18. The method of claim 14 , further comprising, coating the master with a release film, before the covering of the surface contour, to facilitate removal of the master.

19. The method of claim 14 , further comprising, etching to remove the master.

20. The method of claim 14 , wherein the layer of material is a metal.

21. The method of claim 14 , wherein the layer of material is nickel.

22. The method of claim 14 , further comprising removing residual air during the injection molding.

23. The method of claim 14 , further comprising forming vents in the mald insert.

24. The method of claim 14 , wherein the negative image is filled with a polymer.

25. The method of claim 14 , wherein the negative image is filled with one of polyethylene, polypropylene, acrylic, cyclic olefinic copolymers, polyamide, polystyrene, polyester and polycarbonate.

26. The method of claim 16 , wherein the drilling is performed via lasers.

27. The method of claim 14 , wherein the layer of material is formed via sintering.

28. The method of claim 14 , wherein the filling step further comprises:

filling the negative image with a flowable powdered metallic material; and

sintering the powdered metallic material to form the micro-device.

29. The method of claim 14 , wherein the master is formed from silicon.

30. The method of claim 29 , further comprising:

individually forming portions of the master from silicon; and

connecting the portions into a complete master.

31. A method of forming a device including a plurality of micron or sub-micron sized features, the method comprising:

providing a master having a surface contour defining features;

coating the surface contour of the master with at least one layer of material at about 0.07 inches thick;

removing the master from the layer of material to form a negative image of the surface contour in the layer of material; and

filling the negative image to form a device having substantially the same features as the master.

32. The method claim 31 , further comprising, forming a mold insert from the negative image; and

performing injection molding to fill the negative image.

33. The method of claim 32 , wherein the injection molding is done at a vacuum.

34. The method of claim 31 , wherein the negative image is filled with a polymer.

35. The method of claim 34 , wherein the negative image is filled with one of polyethylene, polypropylene acrylic, cyclic olefinic copolymers, polyamide, polystyrenes, polyester and polycarbonate.

36. A method of forming a medical device including a plurality of micron or sub-micron sized features which form skin penetration members, the method comprising:

providing a master having a surface contour defining skin penetration features;

coating the surface contour of the master with a single layer of material having a thickness of about 0.01-0.2 inches;

removing the master from the layer of material to form a negative image of the surface contour in the layer of material

forming a mold insert from the negative image; and

performing injection molding to fill the negative image fluidically to form the medical device having substantially the same features as the master.

37. The method of claim 36 , wherein the injection molding is done at a vacuum.

38. The method of claim 36 , wherein the negative image is filled with a polymer.

39. The method of claim 38 , wherein the negative image is filled with one of polyethylene, polypropylene, acrylic, cyclic olefinic copolymers, polyamide, polystyrenes, polyester and polycarbonate.