Forming integrated inductors and transformers with embedded magnetic cores

Abstract

In accordance with an embodiment of the application a method of forming an integrated magnetic device is described. A prepreg or core is mounted on a carrier. A winding layer is plated and patterned on the prepreg or core. Vias are plated. The silicon is placed on a die attach pad, ensuring sufficient clearance of die to vias and d/a char. The assembly is laminated and grinded to expose the vias. A 2 nd layer of vias is provided by sputtering or plating followed by laminating assembly; and grinding assembly to expose vias. The windings are plated and patterned. A solder mask (SMSK) is applied and assembly finished.

What is claimed is: 
     
         1 . A method of forming an integrated magnetic device package assembly, the method comprising:
 mounting a on a carrier;   plating and patterning a winding layer on the core;   providing a plurality of vias;   plating the plurality of vias;   placing silicon on a die attach pad, ensuring sufficient clearance of die to vias;   laminating the assembly;   grinding the assembly to expose the plurality of vias;   providing a second layer of vias by sputtering;   laminating the assembly again;   grinding the assembly to expose the vias;   plating and patterning the windings; and   solder mask SMSK.   
     
     
         2 . The method of  claim 1 , wherein the windings are of 100 um pitch and of 25 um-50 um thickness. 
     
     
         3 . The method of  claim 1 , wherein the silicon is can be 50-70 um thick. 
     
     
         4 . The method of  claim 1 , wherein the second layer of vias is 25 um tall and 25 um in diameter. 
     
     
         5 . The method of  claim 1 , wherein the core is prepreg. 
     
     
         6 . The method of  claim 1 , wherein the second layer of vias are plated. 
     
     
         7 . A method of forming an integrated magnetic device package assembly, the method comprising:
 planarizing a copper CU sheet;   applying an insulating layer to the top surface of the Cu sheet;   sputtering a plurality of magnetic layers on the top surface of the insulating layer;   pattern the magnetic layers;   etch the magnetic layers;   plating a plurality of vias;   annealing a magnetic material of the magnetic layers in a magnetic field;   laminating the assemblies using film;   grinding the assemblies to expose the plurality of vias;   plating and patterning a plurality of windings;   laminating a top number of windings of the plurality of windings;   stripping the CU sheet from assembly;   applying and patterning a bottom number of windings of the plurality of windings; and   solder mask (SMSK).   
     
     
         8 . The method of forming an integrated magnetic device, as recited in  claim 7 , wherein the magnetic layers are selected from NiFe or Ta2O5. 
     
     
         9 . The method of forming an integrated magnetic device, as recited in  claim 7 , wherein anneal chambers can accommodate 16×20″ panels. 
     
     
         10 . The method of forming an integrated magnetic device, as recited in  claim 7 , wherein the vias include bar vias. 
     
     
         11 . The method of forming an integrated magnetic device, as recited in  claim 10 , wherein the bar vias are used as stiffeners outside of the package. 
     
     
         12 . The method of forming an integrated magnetic device, as recited in  claim 7 , wherein planarizing a copper CU sheet is done using chemical mechanical planarizing (CMP). 
     
     
         13 . The method of forming an integrated magnetic device, as recited in  claim 7 , wherein laminating the assemblies using prepreg instead of film.