High Speed, High Resolution X-ray System for Inspecting Integrated Circuits

A new type of x-ray microscope is proposed for three-dimensional imaging of integrated circuits, or IC"s. The new microscope can image at resolutions down to 25 nm, and at speeds of over 10 million pixels per second. This imaging rate is over 1000x faster than existing high-resolution x-ray systems, and can image a full 1 cm chip in a few hours; existing x-ray microscopes would take years to accomplish the same task. This high-speed imaging is accomplished by increasing the number of x-rays illuminating the sample, i.e., the x-ray flux. The flux is increased first by using a wide spectrum of x-ray energies, rather than a monochromatic beam. Second, the system takes advantage of the 2-dimensional nature of integrated circuits by using a high numerical aperture, or NA. A high NA decreases the depth-of-field for the system, but increases the amount of x-ray light admitted to the camera. The result is a high-speed, high-resolution x-ray microscope for thin, flat samples.