Integrated Circuit Packages, Devices Using the Same, and Methods of Forming the Same

In an embodiment, a device includes: an integrated circuit package including: a package component; and a package stiffener attached to the package component; and a heat spreader attached to the integrated circuit package, a main portion of the heat spreader disposed above the package stiffener, a protruding portion of the heat spreader extending through the package stiffener; an elastic adhesive material between the main portion of the heat spreader and the package stiffener; and a thermal interface material between the protruding portion of the heat spreader and the package component, the thermal interface material different from the elastic adhesive material.