Abstract: In accordance with some embodiments, a package-on-package (PoP) structure includes a first semiconductor package having a first side and a second side opposing the first side, a second semiconductor package having a first side and a second side opposing the first side, and a plurality of inter-package connector coupled between the first side of the first semiconductor package and the first side of the second semiconductor package. The PoP structure further includes a first molding material on the second side of the first semiconductor package. The second side of the second semiconductor package is substantially free of the first molding material.

Abstract: A bubble micro-pump includes a first component, a second component and a bubble-generating unit. The first component includes a flow path having a first area and a second area. The second component above the first component has a first roughness surface and a second roughness surface. The first roughness surface opposite the first area has a first roughness factor, and the second roughness surface opposite the second area has a second roughness factor smaller than the first roughness factor. The bubble-generating unit on the first component generates bubble in the first area and the second area when a fluid fills the vacancy between the first component and the second component. Due to the difference in roughness factor, the backfilling velocity of the fluid in the first area is faster than that in the second area when the bubble starts to vanish, such that the fluid is driven to flow.