IC package including multi-chip unit with bonded integrated heat spreader

A method of fabricating an integrated circuit package, the method comprising:

• coupling a first integrated circuit chip to a redistribution layer (RDL) structure, the RDL structure having a first sidewall and a second sidewall, the second sidewall laterally opposite to the first sidewall, the first integrated circuit chip comprising a first silicon substrate over an active region, the first silicon substrate having a backside opposite the active region, and the first silicon substrate having a first sidewall and a second sidewall between the active region and the backside, the second sidewall laterally opposite the first sidewall;
• coupling a second integrated circuit chip to the RDL structure, the second integrated circuit chip laterally spaced apart from the first integrated circuit chip, the second integrated circuit chip comprising a second silicon substrate over an active region, the second silicon substrate having a backside opposite the active region, and the second silicon substrate having a first sidewall and a second sidewall between the active region and the backside, the second sidewall laterally opposite the first sidewall;
• forming a dielectric material layer laterally between and in contact with the second sidewall of the first silicon substrate and the first sidewall of the second silicon substrate, the dielectric material in contact with the RDL structure;
• forming a back-side bond material over the backside of the first silicon substrate, over the dielectric material layer, and over the backside of the second silicon substrate;
• forming a bond material over the back-side bond material, the bond material separate and distinct from the back-side bond material;
• coupling a heat spreader to the bond material, the heat spreader having a first sidewall and a second sidewall, the second sidewall laterally opposite to the first sidewall, wherein the first sidewall of the heat spreader is in vertical alignment with the first sidewall of the RDL structure, and the second sidewall of the heat spreader is in vertical alignment with the second sidewall of the RDL structure;
• and
• forming a package mold material adjacent to a sidewall of the dielectric material and a sidewall of the RDL structure.