In a method for fabricating a semiconductor, a first conductive pattern structure partially protruding upwardly from first insulating interlayer is formed in first insulating interlayer. A first bonding insulation layer pattern covering the protruding portion of first conductive pattern structure is formed on first insulating interlayer. A first adhesive pattern containing a polymer is formed on first bonding insulation layer pattern to fill a first recess formed on first bonding insulation layer pattern. A second bonding insulation layer pattern covering the protruding portion of second conductive pattern structure is formed on second insulating interlayer. A second adhesive pattern containing a polymer is formed on second bonding insulation layer pattern to fill a second recess formed on second bonding insulation layer pattern. The first and second adhesive patterns are melted. The first and second substrates are bonded with each other so that the conductive pattern structures contact each other.