Analysis of IC's electromagnetic field print throughout a decapsulation procedure

Electromagnetic Analysis (EMA) had become a field of interest well studied among academic researchers because it can be expand so that sensitive data to be explored from electromagnetic leakages. Crypto security implies, among other, immunity to the study of a circuit's electromagnetic footprint, fore mostly via decapsulation. The decapsulation of an integrated circuit (IC) can be made by applying chemicals (such as nitric or sulfuric acid, followed by acetone) or by using mechanical milling up to a point. The target IC's are microcontrollers, memory circuits, which can store sensitive data, but also other distinctive IC's. This paper reports a new technique used to explore the internal structure of an integrated circuit and measure its electromagnetic field. Mixed decapsulation was performed (chemical and mechanical) in order to measure the electromagnetic field after each layer of epoxy. The main idea was to study the electromagnetic pattern of a certain type of operations implemented in a microcontroller. The electromagnetic footprint has a distinctive pattern for each IC, depending on the type of operations that are made, and was measured with in-house built antenna-probes, but also with commercial probes.