Structure and method of making interconnect element, and multilayer wiring board including the interconnect element

1. A method of fabricating an interconnect element, comprising:

fabricating a first metal layer overlying a carrier layer, the first metal layer comprised of a first metal and including a plurality of metal traces, each of the metal traces having a first surface overlying the carrier layer, an opposed second surface, and an edge surface extending between the first and second surfaces;

providing a dielectric element to overlie said metal layer and said carrier layer such that outer surfaces of said plurality of metal traces and a first major surface of said dielectric element are adjacent to said carrier layer, and inner surfaces of said plurality of metal traces are disposed within recesses in said dielectric element remote from said outer surfaces, said dielectric element having a second major surface remote from said first major surface;

providing a plurality of metal posts extending from said inner surfaces of said plurality of metal traces at least to said second major surface of said dielectric element, said posts formed from a second metal;

plating an etching metal layer comprised of a third metal between each of said plurality of posts and said metal traces, the etching metal layer extending along said edge surfaces of said plurality of metal traces; and

etching said carrier layer to expose said first major surface of said dielectric element and portions of said outer surfaces of said plurality of metal traces not protected by said etching layer,

wherein the etching metal layer protects surfaces of said posts and portions of said first metal layer not protected by said etching layer during the step of etching.

2. The method as claimed in claim 1 , wherein said outer surfaces of said plurality of metal traces are substantially coplanar with said first major surface of said dielectric element.

3. The method as claimed in claim 1 , wherein said carrier layer includes a fourth metal and said plurality of metal traces are formed by patterning openings in a layer of photoresist and plating said plurality of metal traces within said openings.

4. The method as claimed in claim 3 , further comprising providing an etch-resistant layer on said carrier layer prior to plating said plurality of metal traces within said openings such that during said step of removing said carrier layer, said etch-resistant layer protects said plurality of metal traces from being attacked during said step of removing said carrier layer.

5. The method as claimed in claim 1 , wherein said step of providing said plurality of metal posts includes etching a layer of metal overlying said inner surfaces of said plurality of metal traces and said step of providing said dielectric element includes forming said dielectric element after said plurality of metal posts are provided to extend from said inner surfaces of said plurality of metal traces.

6. A method of making a multilayer interconnect element including the method of making an interconnect element as claimed in claim 2 , said method further comprising simultaneously joining said plurality of posts of a first one of said plurality of interconnect elements to said outer surfaces of said plurality of metal traces of a second one of said plurality of interconnect elements and joining said first major surface of a dielectric element of a first one of said interconnect elements to a second major surface of a dielectric element of a second one of said interconnect elements.

7. The method as claimed in claim 6 , wherein said step of simultaneously joining also joins said plurality of posts of said second one of said plurality of interconnect elements to said outer surfaces of said plurality of metal traces of a third one of said plurality of interconnect elements.

8. The method of making a multilayer interconnect element as claimed in claim 7 , wherein said step of simultaneously joining includes simultaneously fusing a bond metal disposed between said plurality of posts of said first one of said plurality of interconnect elements and said plurality of metal traces of said second one of said plurality of interconnect elements and fusing a bond metal disposed between said plurality of posts of said second one of said plurality of interconnect elements and said plurality of metal traces of said third one of said plurality of interconnect elements.

9. A method of manufacturing a multilayer wiring board including a plurality of wiring boards, wherein a plurality of interconnection layers, made from a first metal, are fabricated on one primary surface of an interlayer insulation layer in an embedded state so that a primary surface of said interconnection layers will be coplanar with said one primary surface of said interlayer insulation layer, each of said plurality of interconnection layers further comprising an opposed surface opposite the primary surface of the interconnection layer and an edge surface extending between the primary and opposed surfaces;

fabricating a plurality of interlayer contact pillars from a second metal on at least a part of said plurality of said interconnection layers, the plurality of interlayer contact pillars extending away from the opposed surfaces of said plurality of interconnection layers, so as to extend through said interlayer insulation layer, and be exposed at an opposed surface of said interlayer insulation layer opposite the primary surface of said interlayer insulation layer;

plating an etching metal layer comprised of a third metal between each of said plurality of interlayer contact pillars and said interconnection layers, said etching metal layer extending along said edge surfaces of said plurality of interconnection layers;

depositing a low melting point metal layer for improving connectivity on said exposed surface of said interlayer contact pillar; and

joining said plurality of prepared wiring boards in a stack such that the interlayer insulation layers of adjacent wiring boards will be fused and integrated together, along with the interconnection layer of one wiring board connecting to the interlayer contact pillar of another wiring board, or the interlayer contact pillar of one wiring board being connected to the interlayer contact pillar of another wiring board, through a low melting point metal layer for improving connectivity, when connecting, through said low melting point metal layer for improving connectivity, through applying heat and applying pressure when said prepared plurality of wiring boards are in a state wherein said prepared plurality of wiring boards are aligned so that the interconnection layer of one wiring board contacts the interlayer contact pillar of another wiring board, or the interlayer contact pillar of one wiring board contacts the interlayer contact pillar of another wiring board, through said interlayer contact pillar.

10. The method of claim 9 , further comprising etching a carrier layer supporting said interconnection layer,

wherein the etching metal layer protects surfaces of said posts and portions of said interconnection layer during the step of etching.

11. A method of fabricating an interconnect element, comprising:

fabricating a first metal layer overlying a carrier layer, the metal layer comprised of a first metal and including a plurality of metal traces, each of the metal traces having a first surface adjacent the carrier layer, an opposed second surface, and an edge surface extending between the first and second surfaces;

providing a dielectric element to overlie said metal layer and said carrier layer such that outer surfaces of said plurality of metal traces and a first major surface of said dielectric element are adjacent to said carrier layer, and inner surfaces of said plurality of metal traces are disposed within recesses in said dielectric element remote from said outer surfaces, said dielectric element having a second major surface remote from said first major surface;

providing a plurality of metal posts formed from a second metal and extending from said inner surfaces of said plurality of metal traces at least to said second major surface of said dielectric element, said posts having an outer wall surface; and

removing said carrier layer to expose said first major surface of said dielectric element and portions of said first surfaces of said plurality of metal traces,

wherein said metal traces are deposited on the carrier layer so that edge surfaces of the metal traces are spaced inwardly away from the outer wall surfaces of the metal traces and so that a width of said metal traces underlying said metal posts is less than a width of the metal posts extending in a direction along a length of the carrier layer.

12. The method as claimed in claim 11 , further comprising plating an etching metal layer comprised of a third metal between each of said plurality of posts and said metal traces, the etching metal layer extending along said edge surfaces of said plurality of metal traces; and

etching said carrier layer to expose said first major surface of said dielectric element and portions of said first surfaces of said plurality of metal traces not protected by said etching layer.

13. The method as claimed in claim 11 , wherein said carrier layer includes a metal and said plurality of metal traces are formed by patterning openings in a layer of photoresist and plating said plurality of metal traces within said openings.

14. The method as claimed in claim 13 , further comprising providing an etch-resistant layer on said carrier layer prior to plating said plurality of metal traces within said openings such that during said step of removing said carrier layer, said etch-resistant layer protects said plurality of metal traces from being attacked during said step of removing said carrier layer.

15. The method as claimed in claim 11 , wherein said step of providing said plurality of metal posts includes etching a layer of metal overlying said inner surfaces of said plurality of metal traces and said step of providing said dielectric element includes forming said dielectric element after said plurality of metal posts are provided to extend from said inner surfaces of said plurality of metal traces.

16. A method of making a multilayer interconnect element including the method of making an interconnect element as claimed in claim 12 , said method further comprising simultaneously joining said plurality of posts of a first one of said plurality of interconnect elements to said outer surfaces of said plurality of metal traces of a second one of said plurality of interconnect elements and joining said first major surface of a dielectric element of a first one of said interconnect elements to a second major surface of a dielectric element of a second one of said interconnect elements.

17. The method as claimed in claim 16 , wherein said step of simultaneously joining also joins said plurality of posts of said second one of said plurality of interconnect elements to said outer surfaces of said plurality of metal traces of a third one of said plurality of interconnect elements.

18. The method of making a multilayer interconnect element as claimed in claim 17 , wherein said step of simultaneously joining includes simultaneously fusing a bond metal disposed between said plurality of posts of said first one of said plurality of interconnect elements and said plurality of metal traces of said second one of said plurality of interconnect elements and fusing a bond metal disposed between said plurality of posts of said second one of said plurality of interconnect elements and said plurality of metal traces of said third one of said plurality of interconnect elements.

19. The method as claimed in claim 11 , wherein said outer surfaces of said plurality of metal traces are substantially coplanar with said first major surface of said dielectric element.