The rise of contour metrology from niche solution to versatile enabler

The concept of using contours from SEM images for improving metrology results on semiconductor manufacturing applications exists for almost over two decades. However, the usage of contours was limited due to the difficulties encountered while identifying the contours and their consistency to be combined with traditional metrology results. As the technology for detecting contours advanced, so did the challenges, with higher levels of noise, lower contrast, more complex shapes, multiple layers combination, and tighter specifications. More recently, with the high level of sophistication attained by contour metrology, different applications and needs in different fields can be addressed by it. One of the most powerful benefits of using contour metrology is the possibility of combining information coming from the image to a layout, augmenting the metrology capability, pattern intent control and pattern quality. This work presents different strategies for obtaining contours from SEM images as well as multiple applications that are now relying on contours for either improving existing capabilities or proposing new ones that enable processes to continue to advance in future technology nodes.