Barrier structures for underfill containment

An electronic system, comprising:

• a motherboard;
• an integrated circuit assembly electrically attached to the motherboard, wherein the integrated circuit assembly comprises:
• an electronic substrate;
• a first integrated circuit device having a first surface, an opposing second surface, a first side extending between the first surface and the second surface, and a first edge defined at an intersection of the second surface and the first side of the first integrated circuit device, wherein the first surface of the first integrated circuit device is electrically attached to the electronic substrate;
• a second integrated circuit device having a first surface, an opposing second surface, a second side extending between the first surface and the second surface, and a second edge defined at an intersection of the second surface and the second side of the second integrated circuit device, wherein the first surface of the second integrated circuit device is electrically attached to the electronic substrate,
• an underfill material between the first side of the first integrated circuit device and the second side of the second integrated circuit device;
• and
• at least one barrier structure comprising a silicone or fluorocarbon layer on the first side of the first integrated circuit device and adjacent the first edge or on the second surface of the second integrated circuit device and adjacent the second edge, wherein the underfill material abuts, but does not cross, the at least one barrier structure.