The invention relates to a polymorphic form of -modafinil that produces a powder X-ray diffraction spectrum comprising intensity peaks corresponding to interplanar spacings of about 14. According to the CMP method, an interlayer insulating layer having two or more layers is etched to form a trench andor via hole, and a combined thickness of the two or more layers are measured. The shell particles are adhered to the core particle by a polymeric layer.