Multi-step release method for electrochemically fabricated structures

• US 20050072681A1
• Filed: 05/07/2004
• Published: 04/07/2005
• Est. Priority Date: 12/03/2001
• Status: Abandoned Application

• Current Assignee: Microfabrica Incorporated (Technoprobe S.P.A.)
• Original Assignee: Microfabrica Incorporated (Technoprobe S.P.A.)
• Inventors: Cohen, Adam L., Lockard, Michael S., McPherson, Dale S.
• Application Number:
  US10/841,347
• Publication Number:
  US 20050072681A1
• Time in Patent Office: Days
• US Class Current: 205/170
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81C 1/00126 Static structures not provided for in groups B81C1/00031 - B81C1/00119
• CPC Class Codes: B81C 2201/0109 Sacrificial layers not provided for in B81C2201/0107 - B81C2201/0108
• CPC Class Codes: B81C 2201/0197 Processes for making multi-layered devices not provided for in groups B81C2201/0176 - B81C2201/0192
• CPC Class Codes: C23C 18/1605 by masking
• CPC Class Codes: C23C 18/1651 Two or more layers only obtained by electroless plating
• CPC Class Codes: C25D 1/003 3D structures, e.g. superposed patterned layers
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: H01P 1/202 Coaxial filters cascaded coaxial cavities H01P1/205
• CPC Class Codes: H01P 11/00 Apparatus or processes specially adapted for manufacturing waveguides or resonators, lines, or other devices of the waveguide type
• CPC Class Codes: H01P 11/005 Manufacturing coaxial lines
• CPC Class Codes: H01P 11/007 Manufacturing frequency-selective devices resonators H01P11/008
• CPC Class Codes: H01P 3/06 Coaxial lines
• CPC Class Codes: H01P 5/183 at least one of the guides being a coaxial line
• CPC Class Codes: H05K 3/4647 by applying an insulating layer around previously made via studs

Abstract

Multi-layer structures are electrochemically fabricated from at least one structural material (e.g. nickel), that is configured to define a desired structure and which may be attached to a substrate, and from at least one sacrificial material (e.g. copper) that surrounds the desired structure. After structure formation, the sacrificial material is removed by a multi-stage etching operation. In some embodiments sacrificial material to be removed may be located within passages or the like on a substrate or within an add-on component. The multi-stage etching operations may be separated by intermediate post processing activities, they may be separated by cleaning operations, or barrier material removal operations, or the like. Barriers may be fixed in position by contact with structural material or with a substrate or they may be solely fixed in position by sacrificial material and are thus free to be removed after all retaining sacrificial material is etched.

Claims

1. An electrochemical fabrication process for producing a multi-layer three-dimensional structure from a plurality of adhered layers, the process comprising:

(A) forming a layer by depositing at least one sacrificial material and at least one structural material onto a substrate, wherein the substrate may comprise previously deposited layers, and wherein the depositing of at least one of the materials comprises an electrodeposition or electroless deposition operation;

(B) repeating (A) one or more times such that a plurality of layers are formed and such that successive layers are formed adjacent to and adhered to previously formed layers;

(C) performing a first etching operation to remove at least a first portion of at least one material from the plurality of layers or from the substrate; and

(D) performing a second etching operation, which is distinct from the first etching operation, to remove at least a portion of at least one material from the plurality of layers or from the substrate.

3. The process of claim 1 additionally comprising:

(D) supplying a plurality of preformed masks, wherein each mask comprises a patterned dielectric material that includes at least one opening through which deposition can take place during the formation of at least a portion of a layer, and wherein each mask comprises a support structure that supports the patterned dielectric material;

wherein at least a plurality of the selective depositing operations comprise;

(1) contacting the substrate and the dielectric material of a selected preformed mask;

(2) in presence of a plating solution, conducting an electric current through the at least one opening in the selected mask between an anode and the substrate, whereby a selected deposition material is deposited onto the substrate to form at least a portion of a layer; and

(3) separating the selected preformed mask from the substrate.

4. The process of claim 1 wherein a plurality of selective depositing operations comprise:

(1) providing an adhered patterned mask on a surface of the substrate, wherein the mask includes at least one opening;

(2) in presence of a plating solution, conducting an electric current through the at least one opening in the adhered mask between an anode and the substrate, whereby a selected deposition material is deposited onto the substrate to form at least a portion of a layer; and

(3) removing the mask from the substrate.

5. The process of claim 1 wherein a plurality of selective depositing operations comprise:

(1) providing an adhered patterned mask on a surface of the substrate, wherein the mask includes at least one opening;

(2) while the patterned mask is adhered to the substrate, depositing a selected deposition material through the at least one opening in the adhered mask onto the substrate, and

(3) removing the mask from the substrate.

6. The process of claim 1 wherein the first etching operation comprises use of at least a first etchant and a first set of etching parameters and wherein the second etching operation comprises use of at least a second etchant and a second set of etching parameters.

7. The process of claim 6 wherein the first and second etchants are different from one another.

8. The process of claim 7 wherein the first etchant selectively attacks one of the materials of the layers while substantially non-reactive with regard to another material of the layers.

9. The process of claim 6 wherein the first set of etching parameters are different from the second set of etching parameters.

10. The process of claim 6 wherein the first and second etching operations are separated by an intervening operation.

11. The process of claim 1 where the first etching operation removes a first material and the second operation removes a second material which is different from the first material.

12. The process of claim 1 wherein the first etching operation ends at a hard stop.

13. The process of claim 1 where the three-dimensional structure is protected from the first etchant and etching operation by a material that substantially surrounds the structure and, which is not attacked significantly by the first etchant.

14. The process of claim 1 where the three-dimensional structure is protected from the first etchant and etching operation by a barrier material and by a substrate on which the structure is formed which are resistant to the first etching operation.

15. The process of claim 1 where the three dimensional structures is protected from the first etchant and etching operation by a barrier material which has a surface which is at least partially conformal with end spaced from a surface of the structure.

19. The process of claim 12 additionally comprising:

(D) supplying a plurality of preformed masks, wherein each mask comprises a patterned dielectric material that includes at least one opening through which deposition can take place during the formation of at least a portion of a layer, and wherein each mask comprises a support structure that supports the patterned dielectric material;

wherein at least a plurality of the selective depositing operations comprise;

(1) contacting the substrate and the dielectric material of a selected preformed mask;

(2) in presence of a plating solution, conducting an electric current through the at least one opening in the selected mask between an anode and the substrate, whereby a selected deposition material is deposited onto the substrate to form at least a portion of a layer; and

(3) separating the selected preformed mask from the substrate.

2. An electrochemical fabrication process for producing a multi-layer three-dimensional structure from a plurality of adhered layers, the process comprising:

(A) forming a layer by depositing at least one sacrificial material and at least one structural material onto a substrate, wherein the substrate may comprise previously deposited layers, and wherein at least one of the materials comprises a metal or electroless deposition operation;

(B) repeating (A) one or more times such that a plurality of layers are formed and such that successive layers are formed adjacent to and adhered to previously formed layers;

(C) performing a first etching operation to remove at least a first portion of at least one material from the plurality of layers or from the substrate; and

(D) performing a second etching operation, which is distinct from the first etching operation, to remove at least a portion of at least one material from the plurality of layers or from the substrate.

16. An electrochemical fabrication process for producing a three-dimensional structure from a plurality of adhered layers, the process comprising:

(A) forming a layer by depositing at least one sacrificial material and at least one structural material onto a substrate, wherein the substrate may comprise previously deposited layers, and wherein the depositing of at least one of the materials comprises an electrodeposition operation or electroless deposition;

(B) repeating (A) one or more times such that a plurality of layers are formed and such that successive layers are formed adjacent to and adhered to previously formed layers;

(C) performing a first etching operation to remove at least a first portion of at least one material from the plurality of layers or from the substrate;

(D) performing an intervening operation, after performing the first etching operation;

(E) performing a second etching operation, after the intervening operation, to remove at least a portion of at least one material from the plurality of layers or from the substrate.

17. The process of claim 16 additionally comprising:

(F) supplying a plurality of preformed masks, wherein each mask comprises a patterned dielectric material that includes at least one opening through which deposition can take place during the formation of at least a portion of a layer, and wherein each mask comprises a support structure that supports the patterned dielectric material;

wherein at least a plurality of selective depositing operations comprise;

(1) contacting the substrate and the dielectric material of a selected preformed mask;

(2) in presence of a plating solution, conducting an electric current through the at least one opening in the selected mask between an anode and the substrate, whereby a selected deposition material is deposited onto the substrate to form at least a portion of a layer; and

(3) separating the selected preformed mask from the substrate.

18. The process of claim 16 wherein a plurality of selective depositing operations comprise:

(1) providing an adhered patterned mask on a surface of the substrate, wherein the mask includes at least one opening;

(2) in presence of a plating solution, conducting an electric current through the at least one opening in the adhered mask between an anode and the substrate, whereby a selected deposition material is deposited onto the substrate to form at least a portion of a layer; and

(3) removing the mask from the substrate.

20. The process of claim 18 wherein the first etching operation comprises use of at least a first etchant and a first set of etching parameters and wherein the second etching operation comprises use of at least a second etchant and a second set of etching parameters.

21. The process of claim 20 wherein the first and second etchants are different from one another.

22. The process of claim 21 wherein the first etchant selectively attacks one of the materials of the layers while substantially non-reactive with regard to another material of the layers.

23. The process of claim 22 wherein the at least one structural material comprises nickel, the at least one sacrificial material comprises copper, and wherein the first etchant is substantially selective to copper while substantially non-reactive with nickel.

24. The process of claim 16 wherein the intervening operation is an operation that removes etchant from at least one surface that was being etched by the first etching operation.

25. The process of claim 24 wherein the second etching operation uses the same etchant as did the first operation and wherein the second etching operation continues to operate on at least a portion of the at least one surface being etched by the first etching operation.

26. The process of claim 25 wherein the process additionally comprises:

at least a second intervening operation which is performed after the second etching operation; and

at least a third etching operation that is performed after the second intervening operation.

27. The process of claim 16 wherein the intervening operation removes an etching barrier that was protecting at least a portion of the multi-layer structure or substrate during the first etching operation.

28. The process of claim 27 wherein the second etching operation operates to remove material located around a previously protected surface.

29. The process of claim 27 wherein removal of the etching barrier occurs at least in part by use of a planarization operation.

30. The process of claim 28 wherein the first etching operation removes at least portion of a sacrificial material located in a passage or indentation on or within the substrate while the etching barrier protects at least a portion of the multi-layer structure.

31. The process of claim 30 wherein the second etching operation attacks sacrificial material forming part of the plurality of layers.

32. The process of claim 16 wherein the formation of the plurality of layers comprises formation of a desired structure and at least one temporary etching barrier that is adhered to the substrate or to structural material on at least one layer.

33. The process of claim 16 wherein the formation of the plurality of layers comprises formation of a desired structure and at least one temporary etching barrier that is adhered only to sacrificial material.

34. The process of claim 33 wherein the temporary barrier falls away from the desired structure after a surrounding quantity of sacrificial material has been removed.

35. The process of claim 16 wherein the intervening operation includes reorienting the structure with respect to a direction of application of an etchant or with respect to a gravitational force.