Microelectronic assembly with bridge die and selective metallization layers

A microelectronic assembly, comprising:

• a substrate;
• a bridge component in the substrate, the bridge component comprising a first plurality of conductive contacts at a first face of the bridge component;
• and
• a microelectronic component comprising a second plurality of conductive contacts at a first face of the microelectronic component, wherein one of the second plurality of conductive contacts of the microelectronic component is conductively coupled to one of the first plurality of conductive contacts of the bridge component;
• wherein the substrate comprises:
• a first layer comprising a dopant, the first layer extending under the bridge component;
• and
• a second layer comprising the dopant, the second layer extending under the microelectronic component.

An assembly comprising:

• a substrate comprising a first dielectric layer and a second dielectric layer over the first dielectric layer, the first dielectric layer comprising a dopant, and the first dielectric layer having a plurality of conductive structures formed therein;
• a first die having a first face and a second face, the first face of the first die having contacts electrically coupled to the plurality of conductive structures in the first dielectric layer;
• a second die electrically coupled to the first die at the second face of the first die;
• and
• a third die electrically coupled to the first die at the second face of the first die.