Electrochemical fabrication methods with enhanced post deposition processing

• US 20050029225A1
• Filed: 05/07/2004
• Published: 02/10/2005
• Est. Priority Date: 05/07/2002
• Status: Abandoned Application

• Current Assignee: University of Southern California
• Original Assignee: University of Southern California
• Inventors: Zhang, Gang
• Application Number:
  US10/840,998
• Publication Number:
  US 20050029225A1
• Time in Patent Office: Days
• US Class Current: 216/40
• CPC Class Codes: C25D 1/003 3D structures, e.g. superposed patterned layers
• CPC Class Codes: C25D 5/022 using masking means

Abstract

An electrochemical fabrication process for producing three-dimensional structures from a plurality of adhered layers is provided where each layer comprises at least one structural material (e.g. nickel or nickel alloy) and at least one sacrificial material (e.g. copper) that will be etched away from the structural material after the formation of all layers have been completed. An etchant containing chlorite (e.g. Enthone C-38) is combined with a corrosion inhibitor (e.g. sodium nitrate) to prevent pitting of the structural material during removal of the sacrificial material. A simple process for drying the etched structure without the drying process causing surfaces to stick together includes immersion of the structure in water after etching and then immersion in alcohol and then placing the structure in an oven for drying.

Claims

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

(A) selectively depositing a first material onto a substrate to form a portion of a layer and depositing at least a second material to form another portion of the layer, wherein the substrate may comprise previously deposited material, and wherein one of the first material or the second material is a structural material and the other is a sacrificial material;

(B) forming a plurality of layers such that each successive layer is formed adjacent to and adhered to a previously deposited layer, wherein said forming comprises repeating operation (A) a plurality times, wherein during formation of at least one layer an adhered mask is used in selectively depositing the first material; and

(C) after formation of a plurality of layers, separating at least a portion of the sacrificial material from the structural material using an etching solution that comprises ammonium hydroxide, a chlorite salt, and a nitrate salt.

2. 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; and

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

(1) contacting the substrate and the dielectric material of a selected preformed mask or proximately locating the substrate and dielectric material of the 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, wherein the anode comprises a selected deposition material, and wherein the substrate functions as a cathode, such that the 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.

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

(1) adhering a mask having a desired pattern to 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, wherein the anode comprises a selected deposition material, and wherein the substrate functions as a cathode, such that the selected deposition material is deposited onto the substrate to form at least a portion of a layer; and

(3) separating the mask from the substrate.

4. The process of claim 2 wherein the plating solution is at a temperature below about 43°

C. when conduction of the electric current begins.

5. The process of claim 2 wherein the plating solution is at a temperature below about 38°

C. when conduction of the electric current begins.

6. The process of claim 2 wherein the plating solution is not agitated during selective deposition.

7. The process of claim 1 wherein the formation of each of a number of layers comprise at least one blanket deposition as well as the selective deposition wherein for a given layer the selectively deposited material is different from a material deposited by blanket deposition.

8. The process of claim 1 wherein the plurality of selective depositions comprise the deposition of a plurality of different materials.

9. The process of claim 1 wherein at least a portion of one layer is formed by a non-electroplating deposition process.

10. The process of claim 1 wherein a plurality of depositions occur during the formation of each of a number of layers wherein at least one of the depositions on each of the number of layers deposits copper and at least one of the other depositions on the number of layers deposits nickel.

11. The process of claim 1 wherein the selective depositing for each of a number of layers comprises at least two selective depositions.

12. The process of claim 1 wherein a number of the plurality of layers are each formed by depositing at least one structural material using at least one deposition and by depositing at least one sacrificial material by using at least one other deposition.

13. The process of claim 12 wherein at least a portion of the at least one sacrificial material is removed after formation of a plurality of layers to reveal a three-dimensional structure comprised of at least one structural material.

14. The process of claim 2 wherein, for each of a plurality of masks, the support for the dielectric material for a mask comprises the anode involved in the deposition associated with the use of the mask.

15. The process of claim 2 wherein, for each of a plurality of masks, the support for the dielectric material for a mask is a porous medium which does not act as the anode during involved in the deposition associated with the use of the mask.

16. The process of claim 1 wherein the formation of at least a plurality of layers additionally comprises removing a portion of the deposited material from the substrate such that a desired surface level is obtained.

17. The process of claim 1 wherein the at least one sacrificial material comprises copper.

18. The process of claim 1 wherein the at least one structural material comprises nickel.

19. The process of claim 1 wherein the chlorite salt in the etching solution comprises sodium chlorite.

20. The process of claim 1 wherein the nitrate salt comprises sodium nitrate

21. The process of claim 1 wherein during etching, the structure and etchant are moved relative to one another.

22. The process of claim 1 wherein the etching process is aided by application of an electric potential between the substrate and an electrode immersed in the etching solution.

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

(A) selectively patterning a first material on a substrate to form a portion of a layer and depositing at least a second material to form another portion of the layer, wherein the substrate may comprise previously deposited material, and wherein one of the first material or the second material is a structural material and the other is a sacrificial material;

(B) forming a plurality of layers such that each successive layer is formed adjacent to and adhered to a previously deposited layer, wherein said forming comprises repeating operation (A) a plurality times, wherein during formation of at least one layer an adhered mask is used in selectively patterning the first material; and

(C) after formation of a plurality of layers, separating at least a portion of the sacrificial material from the structural material using an etching solution that comprises ammonium hydroxide, a chlorite salt, and a nitrate salt.

24. The process of claim 23 wherein the at least one sacrificial material comprises copper and the at least one structural material comprises nickel.

25. The process of claim 23 wherein the chlorite salt in the etching solution comprises sodium chlorite.

26. The process of claim 23 wherein the nitrate salt comprises sodium nitrate

27. The process of claim 23 wherein during etching, the structure and etchant are moved relative to one another.

28. The process of claim 23 wherein the etching process is aided by application of an electric potential between the substrate and an electrode immersed in the etching solution.

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

(A) selectively depositing a first material onto a substrate to form a portion of a layer and depositing at least a second material to form another portion of the layer, wherein the substrate may comprise previously deposited material, and wherein one of the first material or the second material is a structural material and the other is a sacrificial material;

(B) forming a plurality of layers such that each successive layer is formed adjacent to and adhered to a previously deposited layer, wherein said forming comprises repeating operation (A) a plurality times, wherein during formation of at least one layer an adhered mask is used in selectively depositing the first material; and

(C) after formation of a plurality of layers, separating at least a portion of the sacrificial material from the structural material using an etching solution that comprises a corrosion inhibitor.