Patent ID: 6249138
Filing Date: 2001-06-19
Classification: G01R

Abstract:
A method of testing a leakage current caused by a self-aligned silicide process, suitable for monitoring the self-aligned silicide process performed on a metal-oxide semiconductor transistor having no lightly doped drain (LDD) structure, the method comprising:considering parameters for monitoring the self-aligned silicide process, the parameters comprising an area current density (J.sub.A), an edge current density (J.sub.E), and a corner current density (J.sub.C), a total current (J) of the metal silicide layer being calculated from an equation as follows:J=J.sub.A.times.A+J.sub.E.times.L+J.sub.C.times.C,wherein A is an area of the metal silicide layer, L is an edge perimeter of the metal silicide layer, and C is a corner number for the metal silicide layer;depositing at least three test structures comprising a first test structure, a second test structure, and a third test structure on a wafer, the first test structure, the second test structure and the third test structure respectively comprising a first, a second and a third diffusion regions and a first, a second, and a third metal silicide layer on the first, the second, the third diffusion regions, the first, the second and the third diffusion regions being respectively surrounded by a first, a second, and a third isolation structures, wherein an area of the first metal silicide layer of the first test structure is A.sub.1, its edge perimeter is L.sub.1, its corner number is C.sub.1, an area of the second metal silicide layer of the second test structure is A.sub.2, its edge perimeter is L.sub.2, its corner number is C.sub.2, and an area of the third metal silicide layer of the third test structure is A.sub.3, its edge perimeter is L.sub.3, its corner number is C.sub.3 ;measuring electricity of the first test structure, the second test structure, and the third test structure to respectively obtain total currents J.sub.1, J.sub.2, and J.sub.3, and then substituting these values into a total current equation to obtain three linear equations:J.sub.1 =J.sub.A.times.A.sub.1 +J.sub.E.times.L.sub.1 +J.sub.C.times.C.sub.1,J.sub.2 =J.sub.A.times.A.sub.2 +J.sub.E.times.L.sub.2 +J.sub.C.times.C.sub.2, andJ.sub.3 =J.sub.A.times.A.sub.3 +J.sub.E.times.L.sub.3 +J.sub.C.times.C.sub.3,which three linear equations are then used to obtain a set of values for J.sub.A, J.sub.E, and J.sub.C ; andmonitoring the self-aligned silicide process according to the set of values for J.sub.A, J.sub.E, and J.sub.C.