Maurice H. Hanes

A Microelectronic Test Structure For Thickness Determination Of Homogeneous Conducting Thin Films In VLSI Processing

This paper describes a new test structure for use in determining the thickness of a uniform conducting film. The structure incorporates the van der Pauw cross method to determine the effective sheet resistance of a vertical, uniformly doped cross section of a polysilicon film and a bridge resistor to determine thickness of the film. By using a composite structure, which consists of the vertical cross structure and a conventional planar cross-bridge test structure, it is possible to obtain the thickness, linewidth, and resistivity of a conducting line.

Test structure for measurement of conductive film thickness

A top-contact-resistor test structure, measurements made to validate its operation, and supporting analysis for VLSI process monitoring are described. The structure was devised to simulate the ability of a Van de Pauw test structure to provide reliable local values of the sheet resistance of a conducting film but in a plane perpendicular, rather than parallel, to the wafer surface. The objective was to provide access to film thickness through electrical measurements in a manner similar to that in which the sheet resistance measurements obtained from Van der Pauw structures make linewidth measurements possible when used in conjunction with a Kelvin resistor. Resistance measurements performed with this test structure permit calculation of film thickness and bulk resistivity.<<ETX>>