A bonding process includes the following process. A bump is formed on a first electric device. A patterned insulation layer is formed on a second electric device, wherein the patterned insulation layer has a thickness between 5 μm and 400 μm, and an opening is in the patterned insulation layer and exposes the second electric device. The bump is joined to the second electric device exposed by the opening in the patterned insulation layer.