Method of forming a mold and molding a micro-device

• US 20050247666A1
• Filed: 04/29/2005
• Published: 11/10/2005
• Est. Priority Date: 07/12/2002
• Status: Abandoned Application

• Current Assignee: Becton, Dickinson & Co
• Original Assignee: Becton, Dickinson & Co
• Inventors: Lastovich, Alexander G.
• Application Number:
  US11/119,485
• Publication Number:
  US 20050247666A1
• Time in Patent Office: Days
• US Class Current: 216/52
• CPC Class Codes: A61B 17/205 Vaccinating by means of needles or other puncturing devices
• CPC Class Codes: B29C 2045/0094 injection moulding of small-sized articles, e.g. microarticles, ultra thin articles
• CPC Class Codes: B29C 2793/0045 Perforating
• CPC Class Codes: B29C 33/3842 Manufacturing moulds, e.g. shaping the mould surface by machining
• CPC Class Codes: B29C 33/42 characterised by the shape of the moulding surface, e.g. ribs or grooves
• CPC Class Codes: B29C 45/0055 Shaping
• CPC Class Codes: B29L 2031/7544 Injection needles, syringes
• CPC Class Codes: B29L 2031/756 Microarticles, nanoarticles
• CPC Class Codes: B81B 1/006 Microdevices formed as a single homogeneous piece, i.e. wherein the mechanical function is obtained by the use of the device, e.g. cutters

Abstract

A method of forming a device including a plurality of micron or sub-micron sized features is provided. A master having a surface contour defining a plurality of features is provided. The surface contour of the master is coated with at least one layer of material to form a shell. The master is removed from the shell to form a negative image of the surface contour in the shell. The negative image in the shell is filled with material, for example, polycarbonate, polyacrylic, or polystyrene, to form a device having features substantially the same as the master. The negative image may be filled using injection molding, compression molding, embossing or any other compatible technique.

Claims

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;

wherein said surface contour of said master is formed by micro-machining;

covering the surface contour with a layer of material;

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 material to form a device having substantially the same features as the master;

solidifying said flowable material; and

separating said device from said negative image.

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. The method of claim 1, wherein the layer of material has a thickness of about 0.01-0.2 inches.

15. 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 sinterable material;

sintering said sinterable material;

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;

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

separating said device formed from said flowable material from the negative image.

16. The method of claim 15, wherein the filling step further comprises filling by injection molding.

17. The method of claim 16, wherein the injection molding is done at a vacuum.

18. The method of claim 15, further comprising drilling holes in the features of the device to form hollow micro-needles.

19. The method of claim 15, wherein the layer of material is at least 0.07 inches thick.

20. The method of claim 15, wherein the layer of material is about 0.01 to about 0.2 inches thick.

21. The method of claim 15, further comprising, coating the master with a release film, before the covering of the surface contour, to facilitate removal of the master.

22. The method of claim 15, further comprising, etching to remove the master.

23. The method of claim 15, wherein the layer of material is a metal.

24. The method of claim 15, wherein the layer of material is nickel.

25. The method of claim 16, further comprising removing residual air during the injection molding.

26. The method of claim 15, further comprising forming vents in the mold insert.

27. The method of claim 15, wherein the negative image is filled with a polymer.

28. The method of claim 15, wherein the negative image is filled with one of polyethylene, polypropylene, acrylic, cyclic olefinic copolymers, polyamide, polystyrenes, polyester and polycarbonate.

29. The method of claim 18, wherein the drilling is performed via lasers.

30. The method of claim 15, wherein the master is formed by micromachining.

31. The method of claim 15, 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.

32. The method of claim 15, wherein the master is formed from silicon.

33. The method of claim 32, further comprising:

individually forming portions of the master from silicon; and

connecting the portions into a complete master.