FORMING INTEGRATED INDUCTORS AND TRANSFORMERS WITH EMBEDDED MAGNETIC CORES
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.
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.