A chip package and a fabrication method thereof are provided. The chip package includes a semiconductor substrate containing a semiconductor component and a conductive pad thereon. A through hole penetrates the semiconductor substrate from a backside thereof to expose the conductive pad. A redistribution layer is below the backside of the semiconductor substrate and electrically connected to the conductive pad in the through hole. A conductive trace layer is below the redistribution layer and extended along a sidewall of the semiconductor substrate to electrically contact with an edge of the redistribution layer.