Provided is a spot welded joint which includes at least one thin steel plate with a tensile strength of 750 MPa to 1850 MPa and a carbon equivalent Ceq of equal to or more than 0. The method comprises providing a solution comprising a rare earth salt, an alkaline earth metal salt and a copper salt; spraying the solution onto a substrate to provide a film-covered substrate; and heating the film-covered substrate in an atmosphere containing fluorinated gas to provide the fluorinated precursor. In some embodiments, the composition is a resin-linear silicone-containing hot melt composition and the composition comprises a phase separated resin-rich phase and a phase separated linear-rich phase. Thereafter, in a single RIE etching step, the P2 pole tip trench is etched through the dielectric material down to the seed layer, and the induction coil trench is etched through the dielectric material down to the insulation layer. Yet others relate to coping with fixed focus limitations of cell phone cameras, e.