A flexible hybrid electronic (FHE) system includes a carrier, a first redistribution structure on the carrier, a first device on the first redistribution structure, and an encapsulation layer encapsulating the first device. The carrier has a first Young's modulus Y1. The first redistribution structure has a second Young's modulus Y2. The first device and a portion of the encapsulation layer form a top surface of the first redistribution structure to a top surface of the first device is a first portion having a third Young's modulus Y3. The other portion of the encapsulation layer from the top surface of the first device to a top surface of the encapsulation layer is a second portion having a fourth Young's modulus Y4. A ratio of Y3/Y4 is between 1.62 and 1.98; a ratio of Y3/Y2 is between 0.18 and 0.22; and a ratio of Y3/Y1 is between 280.62 and 342.98.