NOVELTY - The base material (1) comprises a joining film (3) containing silicone material and energy beam absorber (4) of 1-30wt%, formed on a substrate (2). The energy beam absorber absorbs irradiated ultraviolet ray to promote adhesiveness of the base material with the substrate to be joined. The average particle diameter of the energy beam absorber substance is 100-1000nm. The ratio of average particle diameter of the energy beam absorber and the average thickness of the joining film is 1.5-10.    USE - Base material for joining e.g. polarizing plates of LCD used in e.g. mobile phone. Can also be used in joining components including transistor, diode, semiconductor element such as memory, piezoelectric element such as quartz oscillator, reflective mirror, optical lens, diffraction grating, optical filter, solar cell, micro electromechanical system (MEMS) components such as micromirror, pressure sensor, acceleration sensor, magnetic disk, optical disk, components of fuel cell, components of organic electroluminescent element, and electrophoretic display element used in video camera, video tape recorder of viewfinder type and monitor direct-view type, television, laptop, car navigation apparatus, pager, electronic notebook, electronic dictionary, calculator, electronic game machine, word processor, workstation, video telephone, television monitor for crime prevention, electronic binoculars, point of sale (POS) terminal, automatic ticket vending machine, medical device such as electronic thermometer, blood pressure meter, blood-glucose meter, electrocardio display device, ultrasonic diagnosing device, fish finder, measuring instrument used in vehicle, aircraft and vessel, and flight stimulator.    ADVANTAGE - The base material can be joined with the substrate or component efficiently and firmly with high dimensional accuracy, under low temperature. Even if the thermal expansion rate difference of the base material and substrate becomes large, the thermal stress generated in the joining interface can be fully reduced, hence generation of curvature and peeling can be prevented reliably.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) joining method which involves supplying a liquid material containing a silicone material and energy beam absorber on the base material. The liquid film is dried to form a joining film. The adhesiveness of the base material with a component is promoted by the energy beam absorber which emits heat by absorbing ultraviolet ray; and    (2) joined assembly.    DESCRIPTION OF DRAWING(S) - The drawing shows the longitudinal cross-sectional view of the base material.    Base material (1)    Substrate (2)    Joining film (3)    Energy beam absorber (4)