Multi-layer, multi-material fabrication methods for producing micro-scale and millimeter-scale devices with enhanced electrical and/or mechanical properties

• US 8,613,846 B2
• Filed: 10/18/2010
• Issued: 12/24/2013
• Est. Priority Date: 02/04/2003
• Status: Expired due to Fees

• Current Assignee: University of Southern California
• Original Assignee: Microfabrica Incorporated (Technoprobe S.P.A.)
• Inventors: Wu, Ming Ting, Larsen, Rulon Joseph III, Kim, Young, Kim, Kieun, Cohen, Adam L., Kumar, Ananda H., Lockard, Michael S., Smalley, Dennis R.
• Primary Examiner(s): Hendricks, Keith
• Assistant Examiner(s): Sherrill, Stefanie
• Application Number:
  US12/906,970
• Publication Number:
  US 20110132767A1
• Time in Patent Office: 1,163 Days
• Field of Search: 205/118
• 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 1/06716 Elastic
• CPC Class Codes: G01R 1/06744 Microprobes, i.e. having dimensions as IC details
• CPC Class Codes: G01R 1/06755 Material aspects
• CPC Class Codes: G01R 3/00 Apparatus or processes specially adapted for the manufacture or maintenance of measuring instruments , e.g. of probe tips
• CPC Class Codes: H01L 21/4853 Connection or disconnection of other leads to or from a metallisation, e.g. pins, wires, bumps

Abstract

Some embodiments of the invention are directed to electrochemical fabrication methods for forming structures or devices (e.g. microprobes for use in die level testing of semiconductor devices) from a core material and a shell or coating material that partially coats the surface of the structure. Other embodiments are directed to electrochemical fabrication methods for producing structures or devices (e.g. microprobes) from a core material and a shell or coating material that completely coats the surface of each layer from which the probe is formed including interlayer regions. Additional embodiments of the invention are directed to electrochemical fabrication methods for forming structures or devices (e.g. microprobes) from a core material and a shell or coating material wherein the coating material is located around each layer of the structure without locating the coating material in inter-layer regions. Each of these groups of embodiments incorporate both the core material and the coating material during the formation of each layer and each layer is also formed with a sacrificial material that is removed after formation of all layers of the structure. In some embodiments the core material may be a genuine structural material while in others it may be only a functional structural material (i.e. a material that would be removed with sacrificial material if it were accessible by an etchant during removal of sacrificial material.

Claims

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

(a) forming a first layer comprising at least one structural material and at least one sacrificial material;

(b) forming at least one additional layer from at least one structural material and at least one sacrificial material wherein the at least one additional layer is formed on and adhered to a previously formed layer, and wherein the first layer and the at least one additional layer together form a multi-layer three-dimensional structure; and

(c) after formation of a plurality of layers, separating at least a portion of the at least one sacrificial material forming a portion of the plurality of layers from the at least one structural material forming another portion of the plurality of layers,

wherein a given one of the layers comprises at least one sacrificial material and at least two structural materials, wherein the at least two structural materials comprise a core structural material located at a lower boundary surface of the given layer but not at an upper boundary surface of the given layer and a shell structural material bounding the sides of the core material and providing a cap located above the core structural material and below the upper boundary surface of the given layer such that the shell material bounds the top of the core structural material forming part of the given layer, wherein the core structural material and the shell structural material are different,

wherein the lower boundary surface of the given layer is located on an upper boundary surface of a previously formed layer, and

wherein at least one of the at least one structural material and the at least one sacrificial material is electrodeposited.

2. The process of claim 1 wherein prior to forming the given layer the process forms a capping layer comprising a capping structural material that provides a base that in combination with the shell structural material of the given layer completes encapsulation of the core material of the given layer and wherein the capping layer additionally comprises a sacrificial material and wherein the capping structural material and sacrificial material of the capping layer are planarized to set a boundary surface of the capping layer.

3. The process of claim 1 wherein the process comprises formation of a plurality of given layers with each comprising a core structural material, a shell structural material, and a sacrificial material.

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

(a) forming a first layer comprising at least one structural material and at least one sacrificial material;

(b) forming at least one additional layer from at least one structural material and at least one sacrificial material wherein the at least one additional layer is formed on and adhered to a previously formed layer, and wherein the first layer and the at least one additional layer together form a multi-layer three-dimensional structure; and

(c) after formation of a plurality of layers, separating at least a portion of the at least one sacrificial material forming a portion of the plurality of layers from the at least one structural material forming another portion of the plurality of layers,

wherein a given one of the layers comprises at least one sacrificial material and at least two structural materials, wherein the at least two structural materials on the given layer comprise a core structural material and a shell structural material wherein the shell structural material defines sidewalls for at least one upward facing region on the given layer and the at least two structural materials are formed via selective plating of a core region, then selective plating of shell walls around the core region, followed by blanket plating of sacrificial material, and planarization that retains a cap of shell structural material for an upward facing region that overlies the core structural material wherein the core structural material and the shell structural material are different.