Alignment Methods for Navigating Integrated Circuits from the Bulk Side of Silicon Chips
Original Publication Date: 2002-Apr-10
Included in the Prior Art Database: 2002-Apr-10
Techniques are described to enable accurate navigation of an integrated circuit while viewing the IC with infrared light through the silicon substrate. The techniques involve the creation of navigation landmarks on the back surface of the silicon substrate, and the subsequent measurement of the positions of these landmarks relative to the IC's internal circuitry. The relative positions can be accurately measured using one of three techniques described herein: (1) measuring the relative positions of the centers of symmetric patterns, (2) using vernier patterns, or (3) inferring the relative positions of two diffraction gratings from diffraction patterns.