Electroformed chemically milled probes for chip testing

Claim 1

A method of fabricating microcircuit test probes having a selected configuration of circuit leads supported on a carrier with an array of probe contacts affixed to the leads, the method comprising the steps of: applying layers of photoresist to opposite sides of a metal foil sheet to form a panel; exposing the photoresist along a first side of the panel through first mask defining a lead pattern; exposing the photoresist along a second side of the panel through a second mask defining a contact pattern; developing the photoresist to form a pattern of exposed metal foil along the first side corresponding to the lead pattern image and a plurality of holes exposing metal foil along the second side of the panel corresponding to the contact pattern image; placing the panel in an electroplating bath and electroforming contact posts in said holes and leads in said lead pattern image; stripping the remaining photoresist from opposite sides of the panel; applying a layer of dielectric plastic along the contact side of the panel to encase the contacts; removing the outer portion of the dielectric plastic layer and the outer ends of the contacts to develop a substantially planar outer surface; adding respective layers of photoresist along the outer surfaces on both sides of the panel; exposing the added photoresist along the contact side of the panel through said second mask; developing hole patterns in said layer of photoresist added to the contact side of the panel corresponding to said second mask; placing said panel in an electroplating bath to further build up the contact posts in the pattern of holes in said added photoresist; removing at least the photoresist along the lead side of the panel; selectively etching the foil sheet to eliminate metal bridging between respective sets of leads and contacts; and removing all remaining photoresist to leave a pattern of leads with associated contact posts extending through the layer of plastic dielectric.

Claim 2

A method of fabricating microcircuit test probes having a selected configuration of circuit leads supported on a carrier with an array of probe contacts affixed to the leads, the method comprising the steps of: applying layers of photoresist to opposite sides of a metal foil sheet to form a panel; exposing the photoresist along a first side of the panel through first mask defining a lead pattern; exposing the photoresist along a second side of the panel through a second mask defining a contact pattern; developing the photoresist to form a pattern of exposed metal foil along the first side corresponding to the lead pattern image and a plurality of holes exposing metal foil along the second side of the panel corresponding to the contact pattern image; placing the panel in an electroplating bath and electroforming contact posts in said holes and leads in said lead pattern image; stripping the remaining photoresist from opposite sides of the panel; applying a layer of dielectric plastic along the contact side of the panel to encase the contacts; removing the outer portion of the dielectric plastic layer and the outer ends of the contacts to develop a substantially planar outer surface; adding respective layers of photoresist along the outer surfaces on both sides of the panel; exposing the added photoresist along the contact side of the panel through said second mask; developing hole patterns in said layer of photoresist added to the contact side of the panel corresponding to said second mask; placing said panel in an electroplating bath to further build up the contact posts in the pattern of holes in said added photoresist; removing at least the photoresist along the lead side of the panel; selectively etching the foil sheet to eliminate metal bridging between respective sets of leads and contacts; and removing all remaining photoresist to leave a pattern of leads with associated contact posts extending through the layer of plastic dielectric.

Claim 16

A method for manufacturing microcircuit test probes comprising the steps of: (a) laminating a metal foil sheet on a top side and a bottom side with a thick layer of photoresist; (b) exposing said bottom side photoresist to an image of a hole pattern; (c) developing said image of said hole pattern to expose a plurality of openings in said photoresist corresponding to said hole pattern; (d) electroforming posts in said openings; (e) stripping said photoresist from said top and bottom sides of said foil sheet; (f) coating said bottom side of said foil sheet and said posts with a dielectric plastic to leave a flat surface; (g) removing a surface layer of said plastic to just expose areas of said posts having a maximum cross section; (h) laminating the foil-plastic sheet left by step (g) on a top and a bottom side with photoresist; (i) repeating steps (b), (c), and (d); (j) exposing said top side photoresist to an image of a lead pattern; (k) developing said lead pattern image to expose a plurality of openings on said top side of said foil sheet; (l) chemically milling said openings on said top side of said metal sheet with an etchant while protecting sad bottom side from contact with said etchant for a time sufficient to form a plurality of leads with posts connected thereto; and (m) removing all remaining photoresist to leave a pattern of leads with connecting posts extending through a layer of plastic dielectric.

Claim 17

A method for manufacturing microcircuit test probes comprising the steps of: (a) laminating a metal foil sheet on a top side and a bottom side with a thick layer of photoresist; (b) exposing said bottom side photoresist to an image of a hole pattern; (c) developing said image of said hole pattern to expose a plurality of openings in said photoresist corresponding to said hole pattern; (d) electroforming posts in said openings; (e) stripping said photoresist from said top and bottom sides of said foil sheet; (f) coating said bottom side of said foil sheet and said posts with a dielectric plastic to leave a flat surface; (g) removing a surface layer of said plastic to just expose areas of said posts having a maximum cross section; (h) laminating the foil-plastic sheet left by step (g) on a top and a bottom side with photoresist; (i) repeating steps (b), (c), and (d); (j) exposing said top side photoresist to an image of a lead pattern; (k) developing said lead pattern image to expose a plurality of openings on said top side of said foil sheet; (l) chemically milling said openings on said top side of said metal sheet with an etchant while protecting sad bottom side from contact with said etchant for a time sufficient to form a plurality of leads with posts connected thereto; and (m) removing all remaining photoresist to leave a pattern of leads with connecting posts extending through a layer of plastic dielectric.