the sample application_number US 81305001 A description it is to be understood and appreciated that the process steps and structures described below do not cover a complete process flow the present invention can be practiced in conjunction with various integrated circuit fabrication techniques that are used in the art and only so much of the commonly practiced process steps are included herein as are necessary to provide an understanding of the present invention the present invention will be described in detail with reference to the accompanying drawings it should be noted that the drawings are in greatly simplified form and they are not drawn to scale moreover dimensions have been exaggerated in order to provide a clear illustration and understanding of the present invention referring to fig1 a substrate 100 having a photoresist layer 102 thereon is shown the substrate 100 can be a semiconductor substrate such as a silicon wafer but it is not necessarily a semiconductor substrate the substrate 100 can also comprise either a dielectric layer or a conductive layer thereon in fact the substrate 100 depends on the need of analysis the photoresist layer 102 can be any photoresist material used in modern semiconductor industry moreover the photoresist layer 102 can.