Photosensitive organic insulator photo-cell monitoring through advanced macro inspection

In microelectronic device manufacturing, photosensitive organic insulators (POIs) are widely used during passivation steps to protect and preserve the chips from damage due to subsequent processes and from the external environment. To ensure high performance and to maintain chip quality, a well-controlled POI lithography process and corresponding defectivity monitoring are needed. In this work, we present an automated method developed by STMicroelectronics and KLA for POI defectivity and process control employing a KLA 8 Series inspection system with illumination in the visible range. The highly sensitive macro inspection tool with dedicated analysis approaches and solutions successfully enabled the detection of the principal defects of interest, the identification of defectivity root causes through automatic classification and review, and the evaluation of the layer thickness and uniformity through reflected intensity heatmaps. For several months, this protocol has been applied to the production environment, proving to be effective in detecting even small deviations from the standard process. Here, we present some promising results obtained with this strategy, highlighting the benefits in terms of rework reduction and improved equipment management.