System and method for providing mechanical planarization of a sequential build up substrate for an integrated circuit package

A sequential buildup substrate comprising:

• a core substrate;
• a first dielectric layer on a first side of said core substrate;
• a first set of functional circuit elements placed on said first dielectric layer;
• a first set of filler circuit elements placed between said first set of functional circuit elements on said first dielectric layer;
• a second dielectric layer on a second side of said core substrate;
• a second set of functional circuit elements placed on said second dielectric layer;
• a second set of filler circuit elements placed between said second set of functional circuit elements on said second dielectric layer;
• a third dielectric layer placed over said first set of functional circuit elements and over said first set of filler circuit elements and over said first dielectric layer wherein said third dielectric layer has a flat external surface;
• and
• a fourth dielectric layer placed over said second set of functional circuit elements and over said second set of filler circuit elements and over said second dielectric layer wherein said fourth dielectric layer has a flat external surface.

In a sequential buildup substrate of the type comprising functional circuit elements placed on a first dielectric layer, a method for placing over said functional circuit elements a second dielectric layer having a flat external surface, said method comprising the steps of:

• placing filler circuit elements on said first dielectric layer between said functional circuit elements;
• placing a second dielectric layer over said functional circuit elements and over said filler circuit elements and over said first dielectric layer;
• placing a surface of a planarization plate in contact with an external surface of said second dielectric layer;
• heating said external surface of said second dielectric layer to flatten portions of said external surface of said second dielectric layer;
• and
• cooling said second dielectric layer to form a flat external surface on said second dielectric layer.

In a sequential buildup substrate of the type comprising a first set of functional circuit elements placed on a first dielectric layer on a first side of a core substrate and a second set of functional circuit elements placed on second dielectric layer on a second side of said core substrate, a method for placing over said first set of functional circuit elements a third dielectric layer having a flat external surface and placing over said second set of functional circuit elements a fourth dielectric layer having a flat external surface, said method comprising the steps of:

• placing a first set of filler circuit elements on said first dielectric layer between circuit elements of said first set of functional circuit elements;
• placing a second set of filler circuit elements on said second dielectric layer between circuit elements of said second set of functional circuit elements;
• placing a third dielectric layer over said first set of functional circuit elements and over said first set of filler circuit elements and over said first dielectric layer;
• placing a fourth dielectric layer over said second set of functional circuit elements and over said second set of filler circuit elements and over said second dielectric layer;
• placing a surface of a first planarization plate in contact with an external surface of said third dielectric layer;
• placing a surface of a second planarization plate in contact with an external surface of said fourth dielectric layer;
• heating said external surface of said third dielectric layer to flatten portions of said external surface of said third dielectric layer;
• heating said external surface of said fourth dielectric layer to flatten portions of said external surface of said fourth dielectric layer;
• cooling said third dielectric layer to form a flat external surface on said third dielectric layer;
• and
• cooling said fourth dielectric layer to form a flat external surface on said fourth dielectric layer.

A method for providing mechanical planarization of a sequential build up package for an integrated circuit package of the type comprising functional circuit elements placed on a first dielectric layer, said method comprising the steps of:

• placing filler circuit elements on said first dielectric layer between said functional circuit elements;
• placing a second dielectric layer over said functional circuit elements and over said filler circuit elements;
• placing a surface of a planarization plate in contact with an external surface of said second dielectric layer;
• heating said external surface of said second dielectric layer to flatten portions of said external surface of said second dielectric layer;
• moving said planarization plate toward a control gap limit as said portions of said second dielectric layer flatten;
• causing said planarization plate to cease moving when said surface of said planarization plate that is in contact with said external surface of said second dielectric layer reaches said control gap limit;
• cooling said second dielectric layer to form a flat external surface on said second dielectric layer;
• and
• placing a metal conductor layer over said flat external surface of said second dielectric layer, said metal conductor layer having a flat external surface.