Color Vision for Microelectronics Inspection

The rapid and accurate inspection of microelectronic structures is necessary to increase the yield in semiconductor manufacturing. Machine inspection using black and white vision is increasingly being used to automate this function. Recently, color vision has become available as a tool for machine vision. In this paper we present the use of color vision for the measurement of oxide thickness on a silicon wafer. We have achieved a resolution of less than 30 Angstroms in thickness discrimination. The system can also be used to monitor uniformity of oxide thickness across the surface of a wafer. The sensitivity and stability of the method, along with the factors that affect the two, are examined in order to ensure long term stability and repeatability.