Multistep release method for electrochemically fabricated structures

• US 7,303,663 B2
• Filed: 05/07/2003
• Issued: 12/04/2007
• Est. Priority Date: 05/07/2002
• Status: Expired due to Term

• Current Assignee: Microfabrica Incorporated (Technoprobe S.P.A.)
• Original Assignee: Microfabrica Incorporated (Technoprobe S.P.A.)
• Inventors: Cohen, Adam L., McPherson, Dale S., Lockard, Michael S.
• Primary Examiner(s): Wong; Edna
• Application Number:
  US10/434,497
• Publication Number:
  US 20040007468A1
• Time in Patent Office: 1,672 Days
• Field of Search: 205/118, 205/135, 205/170, 205/181, 205/182, 205/220, 205/221, 205/222, 205/223, 205/229
• US Class Current: 205/118
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• 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 1/00476 removing a sacrificial layer B81C1/00912 takes precedence
• CPC Class Codes: B81C 2201/014 by depositing an etch stop layer, e.g. silicon nitride, silicon oxide, metal
• 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 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

Multilayer 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 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 or previously formed layer, wherein the depositing of at least one of the materials comprises an electrodeposition 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, wherein the three-dimensional structure is formed from at least a portion of the at least one structural material that was deposited in (A) and (B);

(C) performing a first etching operation to remove at least a first portion of at least a first material from multiple layers of the plurality of layers, wherein the first material is at least one of the at least one sacrificial material;

(D) performing a second etching operation, after the first etching operation, to remove at least a portion of at least a second material, which is different from the first material, from multiple layers of the plurality of layers and wherein the second material is selected from a group consisting of the at least one sacrificial material and the at least one structural material; and

(E) performing a third etching operation that removes an additional quantity of the first material that was protected from removal by the second material prior to removal of the second material,

wherein the three-dimensional structure is released from the at least one sacrificial material.

2. The process of claim 1 wherein the depositing of at least one sacrificial material and at least one structural material comprise at least one selective depositing operation and wherein the plurality of layers formed are formed using a plurality of selective depositing operations, the process additionally comprising:

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 formation of at least a portion of a layer, and wherein each mask further 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 or the previously formed layer and the dielectric material of a selected preformed mask;

(2) in the presence of a plating solution, performing the electrodeposition operation by conducting an electric current through the at least one opening in the selected mask between an anode and the substrate or the previously formed layer, whereby a deposition material, selected from the group consisting of the at least one sacrificial material and the at least one structural material, is deposited onto the substrate or onto the previously formed layer to form the at least a portion of a layer; and

(3) separating the selected preformed mask from the substrate or previously formed layer.

3. The process of claim 1 wherein the depositing of at least one sacrificial material and at least one structural material further comprises at least one selective depositing operation and wherein the plurality of layers formed are formed using a plurality of selective depositing operations, the process additionally comprising:

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

(2) in the presence of a plating solution, performing the electrodeposition operation by conducting an electric current through the at least one opening in the adhered mask between an anode and the substrate or previously formed layer, whereby a deposition material, selected from the group consisting of the at least one sacrificial material and the at least one structural material, is deposited onto the substrate or previously formed layer; and

(3) removing the mask from the substrate or previously formed layer.

4. The process of claim 1 wherein the performing of the first etching operation comprises use of a first etchant and the first etchant selectively attacks the first material, and is substantially non-reactive with regard to the second material.

5. The process of claim 4 wherein the second material comprises nickel and the first material comprises copper.

6. 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 or previously formed layer, and wherein the depositing of at least one of the materials comprises an electrodeposition 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 wherein the plurality of layers include the three-dimensional structure which is formed from the at least one structural material and which is at least partially surrounded by the at least one sacrificial material;

(C) performing a first etching operation to remove at least a first portion of at least a first sacrificial material, which is one of the at least one sacrificial material, from multiple layers of the plurality of layers;

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

(E) performing a second etching operation, after the intervening operation, to remove an additional quantity of the first sacrificial material from multiple layers of the plurality of layers;

wherein during or after formation of the three-dimensional structure at least one etching barrier is provided to limit removal of a second portion of the first sacrificial material from at least a portion of the three-dimensional structure during the first etching operation, and

wherein the intervening operation removes at least a portion of the etching barrier.

7. The process of claim 6 wherein the formation of the plurality of layers further comprises formation of the at least one etching barrier that is not attacked by the first etching operation and wherein the at least one etching barrier is adhered only to at least one of the at least one sacrificial material.

8. The process of claim 7 wherein the etching barrier falls away from the three-dimensional structure after a surrounding quantity of the at least one sacrificial material has been removed.

9. 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 or previously formed layer, and wherein the depositing of at least one of the materials comprises an electrodeposition 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 wherein the plurality of layers include the three-dimensional structure which is formed from the at least one structural material and which is at least partially surrounded by the at least one sacrificial material;

(C) performing a first etching operation to remove at least a first portion of at least a first material, selected from the group consisting of the at least one sacrificial material and the at least one structural material, from multiple layers of the plurality of layers;

(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 a second material, selected from the group consisting of the at least one sacrificial material and the at least one structural material, from multiple layers of the plurality of layers;

wherein during or after formation of the three-dimensional structure at least one etching barrier is provided to protect at least a portion of the three-dimensional structure, and

wherein the intervening operation comprises a planarization operation which removes at least a portion of the etching barrier.

10. 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 or previously formed layer, and wherein the depositing of at least one of the materials comprises an electrodeposition 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 wherein the plurality of layers include the three-dimensional structure which is formed from the at least one structural material and which is at least partially surrounded by the at least one sacrificial material;

(C) performing a first etching operation to remove at least a first portion of at least a first material, selected from the group consisting of the at least one sacrificial material and the at least one structural material, from multiple layers of the plurality of layers;

(D) performing an intervening operations 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 a second material, which includes at least a portion of the at least one sacrificial material, from multiple layers of the plurality of layers,

wherein during or after formation of the three-dimensional structure at least one etching barrier is provided to protect at least a portion of the three-dimensional structure,

wherein the first portion of at least the first material is at least in part located in a passage within the substrate,

wherein the intervening operation comprises an at least partial removal of the etching barrier, and

wherein the at least portion of the second material was protected by the etching barrier.

11. The process of claim 10 wherein the second etching operation attacks the second material which is a sacrificial material forming part of the plurality of layers.