Various embodiments of an implantable medical device system and methods of forming such systems are disclosed. In one or more embodiments, the implantable medical device system includes a housing, electronics disposed within the housing, and a feedthrough assembly attached to a sidewall of the housing and electrically coupled to the electronics. The feedthrough assembly can include a non-conductive substrate and a feedthrough. The feedthrough can include a via from an outer surface to an inner surface of the non-conductive substrate, a conductive material disposed in the via, and an external contact disposed over the via on the outer surface of the non-conductive substrate, where the external contact is electrically coupled to the conductive material disposed in the via. In one or more embodiments, the external contact is hermetically sealed to the outer surface of the non-conductive substrate by a laser bond surrounding the via.