Method of manufacturing an inductor for a microelectronic device, method of manufacturing a substrate containing such an inductor, and substrate manufactured thereby,

Abstract

A method of manufacturing an inductor for a microelectronic device comprises providing a substrate ( 610 ), forming a first plurality of inductor windings ( 111, 211, 411, 620, 2030 ) over the substrate, forming a magnetic inductor core ( 112, 212, 412, 810 ) over the first plurality of inductor windings, and forming a second plurality of inductor windings ( 113, 213, 413, 1010 ) over the magnetic inductor core. In another embodiment, the method comprises forming the inductor on a sacrificial substrate ( 1610 ) such that the inductor can subsequently be mounted onto a carrier tape ( 1810 ). In yet another embodiment, a method of manufacturing a substrate for a microelectronic device comprises forming an inductor within a build-up layer ( 101, 102, 103, 104 ) of a substrate.

1 . A method of manufacturing an inductor for a microelectronic device, the method comprising:
 providing a substrate;   forming a first plurality of inductor windings over the substrate;   forming a magnetic inductor core over the first plurality of inductor windings; and   forming a second plurality of inductor windings over the magnetic inductor core.   
     
     
         2 . The method of  claim 1  wherein:
 forming the first plurality of inductor windings comprises:
 depositing a metallic seed layer on the substrate; 
 patterning the metallic seed layer in order to define a plating region on the metallic seed layer; and 
 plating an electrically conductive material onto the metallic seed layer such that the electrically conductive material is located only in the plating region. 
   
     
     
         3 . The method of  claim 1  wherein:
 forming the magnetic inductor core comprises:
 depositing a magnetic material; 
 patterning the magnetic material in order to define a core region; and 
 shaping the magnetic material such that it is confined to the core region. 
   
     
     
         4 . The method of  claim 3  wherein:
 patterning the magnetic material comprises:
 depositing a photoresist mask on the magnetic material; and 
 thermally treating the photoresist mask such that the photoresist mask assumes a rounded shape; and 
   shaping the magnetic material comprises:
 conformally etching the magnetic material such that the magnetic material also assumes a rounded shape. 
   
     
     
         5 . The method of  claim 3  wherein:
 patterning the magnetic material comprises:
 depositing a photoresist mask on the magnetic material using an ink-jet spraying procedure to deposit the photoresist mask with a rounded shape; and 
   shaping the magnetic material comprises:
 conformally etching the magnetic material such that the magnetic material also assumes a rounded shape. 
   
     
     
         6 . The method of  claim 1  wherein:
 forming the magnetic inductor core comprises:
 using an ink-jet spraying procedure to deposit a nano-composite ink over the first plurality of inductor windings; and 
 transforming the nano-composite ink into a magnetic material having a rounded shape. 
   
     
     
         7 . The method of  claim 1  wherein:
 forming the second plurality of inductor windings comprises:
 forming a metallic seed layer; 
 patterning the metallic seed layer in order to define a plating region on the metallic seed layer; and 
 plating an electrically conductive material onto the metallic seed layer such that the electrically conductive material is located only in the plating region. 
   
     
     
         8 . The method of  claim 1  further comprising:
 depositing a first electrically insulating material between the first plurality of inductor windings and the magnetic inductor core; and   depositing a second electrically insulating material between the magnetic inductor core and the second plurality of inductor windings.   
     
     
         9 . The method of  claim 8  further comprising:
 patterning the second electrically insulating material.   
     
     
         10 . A method of manufacturing a substrate for a microelectronic device, the method comprising:
 providing a build-up layer of the substrate, the build-up layer comprising an electrically insulating material;   forming a first plurality of inductor windings in the build-up layer;   forming a magnetic inductor core over the first plurality of inductor windings;   forming a second plurality of inductor windings over the magnetic inductor core; and   forming a top layer of the substrate over the build-up layer.   
     
     
         11 . The method of  claim 10  wherein:
 the build-up layer is one of:
 a first-level die-side build-up layer of the substrate; and 
 a second-level die-side build-up layer of the substrate. 
   
     
     
         12 . The method of  claim 10  wherein:
 forming the first plurality of inductor windings comprises:
 forming a first metallic seed layer in the build-up layer; 
 patterning the first metallic seed layer in order to define a first plating region on the first metallic seed layer; and 
 plating a first electrically conductive material onto the first metallic seed layer such that the first electrically conductive material is located only in the first plating region; and 
   forming the second plurality of inductor windings comprises:
 forming a second metallic seed layer in the build-up layer over the first metallic seed layer; 
 patterning the second metallic seed layer in order to define a second plating region on the second metallic seed layer; and 
 plating a second electrically conductive material onto the second metallic seed layer such that the second electrically conductive material is located only in the second plating region. 
   
     
     
         13 . The method of  claim 12  wherein:
 forming the magnetic inductor core comprises:
 depositing a magnetic material; 
 patterning the magnetic material in order to define a core region; and 
 shaping the magnetic material such that it is confined to the core region. 
   
     
     
         14 . The method of  claim 12  wherein:
 forming the magnetic inductor core comprises:
 using an ink-jet spraying procedure to deposit a nano-composite ink over the first plurality of inductor windings; and 
 transforming the nano-composite ink into a magnetic material having a rounded shape. 
   
     
     
         15 . A method of manufacturing an inductor for a microelectronic device, the method comprising:
 providing a sacrificial substrate;   forming a first metallic seed layer on the sacrificial substrate;   patterning the first metallic seed layer in order to define a first plating region on the first metallic seed layer;   plating a first electrically conductive material onto the first metallic seed layer in order to form a first plurality of inductor windings in the first plating region;   forming a magnetic inductor core over the first plurality of inductor windings;   forming a second metallic seed layer over the magnetic inductor core;   patterning the second metallic seed layer in order to define a second plating region on the second metallic seed layer;   plating a second electrically conductive material onto the second metallic seed layer in order to form a second plurality of inductor windings in the second plating region;   removing at least portions of the first and second metallic seed layers in order to complete a formation of the inductor;   encapsulating the inductor in a mold compound;   separating the inductor from the sacrificial substrate; and   placing the inductor onto a carrier tape.   
     
     
         16 . The method of  claim 15  wherein:
 forming the magnetic inductor core comprises:
 depositing a magnetic material; 
 patterning the magnetic material in order to define a core region; and 
 shaping the magnetic material such that it is confined to the core region. 
   
     
     
         17 . The method of  claim 15  wherein:
 forming the magnetic inductor core comprises:
 using an ink-jet spraying procedure to deposit a nano-composite ink over the first plurality of inductor windings; and 
 transforming the nano-composite ink into a magnetic material having a rounded shape. 
   
     
     
         18 . A substrate for a microelectronic device, the substrate comprising:
 a build-up layer comprising an electrically insulating material;   a first plurality of inductor windings in the build-up layer;   a magnetic inductor core over the first plurality of inductor windings;   a second plurality of inductor windings over the magnetic inductor core; and   a top layer of the substrate over the build-up layer.   
     
     
         19 . The substrate of  claim 18  wherein:
 the magnetic inductor core has a width between approximately 5 microns and approximately 140 microns, a height between approximately 2 microns and approximately 140 microns, and a thickness as great as approximately 20 microns.   
     
     
         20 . The substrate of  claim 18  wherein:
 a winding from the first plurality of inductor windings and a winding from the second plurality of inductor windings come together to form a winding turn; and   the substrate comprises no fewer than 3 and no more than 30 winding turns.   
     
     
         21 . The substrate of  claim 20  wherein:
 each winding has a width of between approximately 5 microns and approximately 50 microns.   
     
     
         22 . The substrate of  claim 21  wherein:
 the magnetic inductor core is a closed-loop magnetic inductor core having a substantially circular shape with a diameter between approximately 30 microns and approximately 900 microns.   
     
     
         23 . The substrate of  claim 18  further comprising:
 a first electrically insulating material between the first plurality of inductor windings and the magnetic inductor core; and   a second electrically insulating material between the magnetic inductor core and the second plurality of inductor windings,   wherein:
 the first electrically insulating material and second electrically insulating material have a thickness no greater than approximately  10  microns. 
   
     
     
         24 . The substrate of  claim 18  wherein:
 the magnetic inductor core comprises a nano-composite ink containing a plurality of magnetic particles; and   each one of the magnetic particles has a largest dimension less than approximately 1 micron.