In an embodiment, a device includes: a first die array including first integrated circuit dies, orientations of the first integrated circuit dies alternating along rows and columns of the first die array; a first dielectric layer surrounding the first integrated circuit dies, surfaces of the first dielectric layer and the first integrated circuit dies being planar; a second die array including second integrated circuit dies on the first dielectric layer and the first integrated circuit dies, orientations of the second integrated circuit dies alternating along rows and columns of the second die array, front sides of the second integrated circuit dies being bonded to front sides of the first integrated circuit dies by metal-to-metal bonds and by dielectric-to-dielectric bonds; and a second dielectric layer surrounding the second integrated circuit dies, surfaces of the second dielectric layer and the second integrated circuit dies being planar.