PATCH PRODUCTION

1 . A microprojection array comprising projections on a surface of a substrate, wherein the microprojection array is produced by a method comprising:

a) providing a mask on the substrate; and,

b) etching the substrate using an etchant and a passivant to thereby control the etching process and form the projections, wherein the passivant does not include oxygen.

2 . A microprojection array according to claim 1 , wherein the mask includes an organic photo-resist.

3 . A microprojection array according to claim 1 , wherein the passivant is a gas including:

a) at least one of:

i) carbon; and,

ii) silicon; and,

b) at least one of:

i) chlorine; and,

ii) fluorine.

4 . A microprojection array according to claim 1 , wherein the passivant is at least one of:

a) a per-fluoride hydrocarbon; and,

b) a fluorinated olefine;

c) Octafluorocyclobutane;

d) Perfluoroisobutene; and,

e) C 4 F 8 .

5 - 6 . (canceled)

7 . A microprojection array according to claim 1 , wherein the method includes, controlling the etching process by varying etching parameters including at least one of:

a) a ratio of the etchant to the passivant;

b) a gas flow for at least one of the etchant and the passivant; and,

c) a pressure for at least one of the etchant and the passivant.

8 . A microprojection array according to claim 7 , wherein the ratio is in the range of 0.25 to 0.60.

9 . A microprojection array according to claim 7 , wherein the pressure of at least one of the etchant and the passivant is in the range of 0 to 26.7 Pa.

10 . A microprojection array according to claim 7 , wherein the pressure of at least one of the etchant and the passivant is in the range of 0.67 to 8.0 Pa.

11 . A microprojection array according to claim 7 , wherein the etchant is supplied at a flow rate in the range of at least one of:

a) 0 to 200 sccm; and,

b) 40 to 120 sccm.

12 . A microprojection array according to claim 7 , wherein the passivant is supplied at a flow rate in the range of at least one of:

a) 0 to 200 sccm; and,

b) 10 to 80 sccm.

13 - 15 . (canceled)

16 . A microprojection array according to claim 1 , wherein the method of producing the microprojection array further includes, performing post-etch processing.

17 . A microprojection array according to claim 16 , wherein the post-etch processing includes, chemically sharpening the projections.

18 - 21 . (canceled)

22 . A microprojection array according to claim 1 , wherein the method of producing the microprojection array further includes, applying a coating to the projections.

23 . A microprojection array according to claim 22 , wherein the coating is a metallic coating.

24 - 26 . (canceled)

27 . A microprojection array according to claim 1 , wherein the method of producing the microprojection array further includes coating the projections with a material.

28 . A microprojection array according to claim 1 , wherein the material is a therapeutic agent.

29 . A microprojection array according to claim 1 , wherein the patch has a surface area of approximately 0.4 cm 2 .

30 . A microprojection array according to claim 1 , wherein the projections have a density of between 1,000-30,000 projections/cm 2 .

31 . A microprojection array according to claim 1 , wherein the projections have a density of 20,000 projections/cm 2

32 . A microprojection array according to claim 1 , wherein the projections have a length of between 10 to 200 μm.

33 . A microprojection array according to claim 1 , wherein the projections have a length of 90 μm

34 . A microprojection array according to claim 1 , wherein the projections have a radius of curvature of greater than 1 μm.

35 . A microprojection array according to claim 1 , wherein the projections have a radius of curvature greater than 5 μm.

36 . A microprojection array according to claim 1 , wherein the projections include a support section and a targeting section.

37 . A microprojection array according to claim 36 , wherein the targeting section has a diameter of less than at least one of:

a) 1 μm; and,

b) 0.5 μm.

38 . A microprojection array according to claim 36 , wherein a length for the targeting section is at least:

a) less than 0.5 μm; and,

b) less than 1.0 μm; and,

c) less than 2.0 μm.

39 . A microprojection array according to claim 36 , wherein a length for the support section is at least one of:

a) for epidermal delivery <200 μm;

b) for dermal cell delivery <1000 μm;

c) for delivery to basal cells in the epithelium of the mucosa 600-800 μm; and,

d) for lung delivery of the order of 100 μm in this case.

40 - 42 . (canceled)