NOVELTY - A liquid film (31) is formed on wiring patterns by supplying liquid material containing silicone material and electroconductive particle. A temporary joining structure (5) at thickness direction of liquid film is pressurized after piling up base materials (21,22) through liquid film. The liquid film is dried to obtain a joining film (3). The wiring patterns are connected through electroconductive particle in joining film when joining base materials, to obtain joined structure (1) by exhibiting adhesiveness on joining film due to provision of energy to joining film.    USE - Method for joining wiring board and driver integrated circuit (IC) package used in manufacture of transmissive LCD device. Can also be used in joining transistor, diode, semiconductor element such as memory, piezoelectric element such as quartz oscillator, reflective mirror, optical lens and diffraction grating, optical element such as optical filter, photoelectric transducer such as solar cell, acceleration sensor, micro electro mechanical system (MEMS) component such as micromirror and pressure sensor, magnetic-recording medium, optical recording medium, organic electroluminescent element, electrophoretic display element, component for fuel cell, circuit board, etc.    ADVANTAGE - The base materials are electrically joined easily and firmly under low temperature hence the fall of dimensional accuracy of the joined structure is prevented. The joint strength of the base materials with respect to the joined structure is increased by irradiating UV ray to the joining film and heating the joining film and providing the compressive force the joining film, hence the damage of the base material is prevented.    DETAILED DESCRIPTION - The silicone material consists of polydimethylsiloxane and silanol group. The surface of the substrate particle made of resin of the electroconductive particle is covered by a metal film. The average particle diameter of the electroconductive particle is 0.5-100 mu m. The content of the electroconductive particle in the joining film is 1-50 mass%. The base materials have the electrically conductive films made of nickel, copper and gold that are protruded as the wiring patterns from the surface located in the joining film side of the insulating substrates. The electrically conductive films are connected through the electroconductive particle in the joining film when joining the base materials through the joining film. The wiring patterns are connected through electroconductive particle in the joining film by irradiating UV ray of wavelength 126-300 nm to the joining film in atmospheric condition and heating the joining film at the temperature of 25-100 degrees C and providing compressive force of 0.2-10 MPa to the joining film. The average thickness of the joining film is 100 nm -100 mu m. The joint strength of the base materials with respect to the joined structure is increased by irradiating UV ray to the joining film and heating joining film and providing compressive force the joining film. An INDEPENDENT CLAIM is included for joined structure.    DESCRIPTION OF DRAWING(S) - The drawing shows a longitudinal cross-sectional view illustrating the joining method. (Drawing includes non-English language text)    Joined structure (1)    Joining film (3)    Temporary joining structure (5)    Base materials (21,22)    Liquid film (31)