Interests in the extendibility are growing after the introduction of the LPP (Laser Produced Plasma) EUV source technology in the semiconductor industry, towards higher average power and shorter wavelength, based on the basic architecture of the established LPP EUV source technology. It is discussed in this article that the power scaling of the 13.5nm wavelength source is essentially possible by a slight increase of the driving laser power, CE (Conversion Efficiency) and EUV collection efficiency by some introduction of novel component technologies. Extension of the EUV wavelength towards BEUV (Beyond EUV), namely 6.x nm is discussed based on the general rule of the UTA (Unresolved Transition Arrays) of high Z ions, and development of multilayer mirrors in this particular wavelength region. Technical difficulties are evaluated for the extension of the LPP source technology by considering the narrower mirror bandwidth and higher melting temperature of the candidate plasma materials. Alternative approach based on the superconducting FEL is evaluated in comparison with the LPP source technology for the future solution.