Planar Cone-Beam Computed Tomography for High-Resolution Industrial Application

摘要

Traditional reconstruction algorithm in computed tomography (CT) requires a square reconstruction matrix, regardless of the particular object shape. It becomes inefficient when reconstructing planar objects such as IC chips which have a large area-to-thickness ratio. This article presents a modified cone-beam reconstruction algorithm which is efficient for planar multilayer objects, by detecting the orientation and dimension parameters of the object for the first projection, a reconstruction volume can be defined in a region that would exactly cover the object area and follow the actual orientation of the object. This new technology is demonstrated in both its general form and a targeted application. Compared to conventional cone-beam CT reconstruction, this new method uses much less computation time and storage, can achieve higher reconstruction resolution in the thickness dimension, and makes layer separation much easier for multilayer objects. These advantages will be demonstrated with two high-resolution CT inspection applications of a stacked IC and an advanced packaging device.