A hypersensitive semiconductor die structure is disclosed, in which flip-chip packaging is used in conjunction with a modified SOI die in which a thick silicon support substrate has been removed to increase sensitivity of the sensing device. Rather than being located beneath layers of interconnects and dielectric, the disclosed structure places the sensing devices close to the surface, more closely exposed to the environment in which sensing is to occur. The structure also allows for the placement of sensing films on nearer to the sensing devices and/or an oxide layer overlying the sensing devices.