A method of making an assembly can include juxtaposing a top surface of a first electrically conductive element at a first surface of a first substrate with a top surface of a second electrically conductive element at a major surface of a second substrate. One of: the top surface of the first conductive element can be recessed below the first surface, or the top surface of the second conductive element can be recessed below the major surface. Electrically conductive nanoparticles can be disposed between the top surfaces of the first and second conductive elements. The conductive nanoparticles can have long dimensions smaller than 100 nanometers. The method can also include elevating a temperature at least at interfaces of the juxtaposed first and second conductive elements to a joining temperature at which the conductive nanoparticles can cause metallurgical joints to form between the juxtaposed first and second conductive elements.

Embodiments of a microelectronic assembly comprise a package substrate, including: a first layer comprising a first plurality of mutually parallel channels of a first material; a second layer comprising columns of the first material; and a third layer comprising a second plurality of mutually parallel channels of the first material. The second layer is between the first layer and the third layer, at least some columns extend between and contact the first plurality of mutually parallel channels and the second plurality of mutually parallel channels, and at least a portion of the first layer, the second layer, and the third layer comprises a second material different from the first material.

Embodiments of a microelectronic assembly include a package substrate comprising: a first layer comprising a first plurality of mutually parallel channels of a first material; a second layer comprising columns of the first material; and a third layer comprising a second plurality of mutually parallel channels of the first material, the second plurality of mutually parallel channels being orthogonal to the first plurality of mutually parallel channels. The second layer is between the first layer and the third layer, at least some columns extend between and contact the first plurality of mutually parallel channels and the second plurality of mutually parallel channels, and at least a portion of the first layer, the second layer and the third layer comprises a second material different from the first material.