Cu—Cu bonding for interconnects on bridge chip attached to chips and packaging substrate

A structure, comprising:

• at least one bridge chip comprising Cu pads on a front side of the at least one bridge chip;
• individual chips bonded to the at least one bridge chip via Cu-to-Cu bonds to form a multi-chip structure, wherein each of the individual chips comprises at least a first Cu pillar having a height Hpillar1 and a second Cu pillar having a height Hpillar2 on a front side of each of the individual chips, wherein Hpillar1>Hpillar2, and wherein the Cu-to-Cu bonds are present between the Cu pads of the at least one bridge chip and the second Cu pillar of each of the individual chips such that the first Cu pillar of each of the individual chips hangs off to a side of the at least one bridge chip;
• and
• a packaging substrate bonded to the multi-chip structure via solder bonds between the first Cu pillar of each of the individual chips and the packaging substrate.