Dual sided embedded die and fabrication of same background

A method of forming a dual sided embedded die system, comprising:

• providing a starting material for an assembly including a top surface and a bottom surface, a plurality of vias, a plurality of plated metal posts, and die pads;
• planarizing the top and bottom surfaces of the starting material to expose the plurality of plated metal posts;
• selectively etching the plurality of plated metal posts from die attach pad DAP areas to form a plurality of cavities;
• photo resist patterning and plating to create a plurality of stiffeners;
• applying a tacky tape to the bottom of the assembly;
• attaching a die to DAP;
• laminating the assembly with a film;
• grinding assembly to expose the Plurality of vias, wherein the grinding includes co-grinding of Silicon;
• totally removing the tacky tape;
• forming a first redistribution layer (RDL) on a backside of the assembly;
• sputtering a seed layer on the backside of the assembly;
• Cu plating the assembly;
• patterning with a photoresist;
• etching the Cu plating;
• and
• removing the photoresist and exposing the seed layer
• forming a second RDL on the frontside of the assembly;
• forming a solder mask (SMSK);
• and
• mounting Surface Mount Devices (SMD).

A method of forming a dual sided embedded die assembly, comprising:

• providing a starting material for an assembly including a plurality of plated Cu posts for a plurality of vias, and die pads;
• planarizing the top and bottom surfaces of the starting material to expose the plurality of plated Cu posts;
• selectively etching the plurality of plated Cu posts from die attach pad (DAP) areas to form a plurality of plated cavities, wherein a stiffener is created by photo resist patterning and plating, wherein leveling is included;
• applying a tacky tape;
• applying a backside stiffener-core to the bottom of the assembly, wherein the backside stiffener-core is composed of a metal;
• attaching a die, face down to DAP;
• laminating assembly with a film;
• grinding assembly expose the plurality of vias, wherein the grinding includes co-grinding of silicon;
• totally removing the tacky tape;
• and
• forming a solder mask (SMSK) and finishing.