Electrochemical fabrication process for forming multilayer multimaterial microprobe structures

• US 7,531,077 B2
• Filed: 01/03/2005
• Issued: 05/12/2009
• Est. Priority Date: 02/04/2003
• Status: Active Grant

• Current Assignee: University of Southern California
• Original Assignee: Microfabrica Incorporated (Technoprobe S.P.A.)
• Inventors: Smalley, Dennis R., Cohen, Adam L., Lockard, Michael S., Kumar, Ananda H.
• Primary Examiner(s): Nguyen; Nam X
• Assistant Examiner(s): Van; Luan V
• Application Number:
  US11/029,221
• Publication Number:
  US 20050215023A1
• Time in Patent Office: 1,590 Days
• Field of Search: 205/118, 205/122, 205/170
• US Class Current: 205/118
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• 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: G01R 1/0483 Sockets for un-leaded IC's having matrix type contact fields, e.g. BGA or PGA devices; Sockets for unpackaged, naked chips for IC's with connecting points around the edges only G01R1/0433
• CPC Class Codes: G01R 1/06716 Elastic
• CPC Class Codes: G01R 1/07357 with flexible bodies, e.g. buckling beams
• CPC Class Codes: G01R 31/2886 Features relating to contacting the IC under test, e.g. probe heads; chucks G01R31/2865 takes precedence, test connections, e.g. test sockets, or probes per se, G01R1/04 or G01R1/06

Abstract

Some embodiments of the invention are directed to the electrochemical fabrication of microprobes which are formed from a core material and a material that partially coats the surface of the probe. Other embodiments are directed to the electrochemical fabrication of microprobes which are formed from a core material and a material that completely coats the surface of each layer from which the probe is formed including interlayer regions. These first two groups of embodiments incorporate both the core material and the coating material during the formation of each layer. Still other embodiments are directed to the electrochemical fabrication of microprobe arrays that are partially encapsulated by a dielectric material during a post layer formation coating process. In even further embodiments, the electrochemical fabrication of microprobes from two or more materials may occur by incorporating a coating material around each layer of the structure without locating the coating material in inter-layer regions.

Claims

1. A fabrication process for forming a multi-material, multi-layer three-dimensional probe structure, comprising:

(a) forming and adhering a multi-material layer to a previously formed layer to a substrate;

(b) repeating the forming and adhering operation of (a) to build up a three-dimensional structure from a plurality of adhered multi-material layers each having a thickness,

wherein the formation of each of a plurality of layers, comprises;

(i) deposition of at least one sacrificial material;

(ii) deposition of at least two structural materials, at least one of which encapsulates the other to formed an encapsulated structural material bounded by an encapsulating structural material and wherein the encapsulated structural material is deposited to have a deposition thickness less than the layer thickness; and

(iii) planarization of the at least one sacrificial material and at least one of the at least two structural materials to set the thickness of the multi-material layer such that the encapsulated material is bounded on the sides and from above by the encapsulating material;

(c) after formation of a plurality of layers, separating at least a portion of the sacrificial material on a plurality of layers from the structural materials on those layers to reveal the multi-material multi-layer three-dimensional probe structure formed from the at least two structural materials.

2. The process of claim 1 wherein one of the structural materials is the same material as the sacrificial material and is fully encapsulated by the other of the structural materials as deposited on a plurality of layers.

3. The process of claim 1 wherein each of the structural materials is different from the sacrificial material.

4. The process of claim 1 wherein the forming and adhering comprise electrodepositing at least one material.