Package structures and methods of forming same

A method, comprising:

• providing an interposer structure including a first region and a second region;
• forming first micro bumps over the first region and second micro bumps over the second region, wherein the first micro bumps have a first height and the second micro bumps have a second height greater than the first height;
• bonding a first die onto the first micro bumps and a second die onto the second micro bumps;
• depositing a molding compound around the first die and the second die;
• bonding the interposer structure to a substrate;
• and
• bonding a heat sink to the first die and the second die.

A package structure, comprising:

• a substrate;
• an interposer bonded to the substrate;
• a first die and a second die bonded to the interposer;
• a thermal interface material (TIM) layer disposed over the first die and the second die;
• and
• a heat sink bonded to the TIM layer,
• wherein a thickness of a first portion of the TIM over the first die is greater than a thickness of a second portion of the TIM over the second die.