The invention concerns a method of flip-chip assembly between first (1) and second (2) components each comprising connection pads (11, 21) on one of the faces of same, referred to as assembly faces, which involves transferring the components onto each other via the assembly faces of same in such a way as to create electrical interconnections between the pads of the first and second components. The invention involves transforming the copper oxide into copper by UV annealing, very locally, in the gap between the components, at least around the areas adjacent to the connection pads. The method according to the invention can be used for any component that is transparent to UV rays, including for substrates made from a plastic material such as substrates made from PEN or PET. The invention also concerns the assembly of two components obtained by the method.