3d stacked-chip package

A package, comprising:

• a first die having a first redistribution layer (RDL) disposed on a first substrate;
• a second die having a second RDL disposed on a second substrate, the second die disposed over the first die with the second RDL bonded to the first RDL;
• a first molding compound disposed over the first die and around the second die;
• a third die having a third RDL disposed on a third substrate, the third die disposed over the first molding compound;
• a second molding compound disposed over the first molding compound and around the third die;
• first vias extending through the second substrate and each contacting at least one conductive element in the first RDL or the second RDL, wherein first spacers electrically insulate the first vias from the second substrate;
• and
• second vias extending through the third substrate and each contacting a conductive element in the third RDL or one of the first vias, wherein second spacers electrically insulate the second vias from the third substrate.

A method, comprising:

• providing a first die having a first redistribution layer (RDL) disposed on a first substrate, the first RDL comprising a first oxide layer;
• providing a second die having a second RDL disposed on a second substrate, the second RDL comprising a second oxide layer
• bonding the first die to the second die by bonding the first oxide layer to the second oxide layer with an oxide-to-oxide bond;
• forming first openings in the second die after the bonding the first die to the second die, the first openings extending through the second substrate and exposing first conductive elements in the first RDL or the second RDL;
• forming first vias in the first openings, the first vias extending through the second substrate and each contacting a respective one of the first conductive elements, wherein the first vias are electrically insulated from the second substrate;
• mounting a third die over the second die, the third die having a third RDL disposed on a third substrate;
• forming second openings in the third die after the mounting the third die over the second die, the second openings each extending through the third substrate and exposing one of the first vias or a second conductive element in the third RDL;
• and
• forming second vias in the second openings, the second vias extending through the third substrate and each contacting a respective one of the second conductive elements or a respective one of the first vias, wherein the second vias are electrically insulated from the third substrate.