A device and method for localizing underfill includes a substrate, a plurality of dies, and underfill material. The substrate includes a plurality of contacts and a plurality of cavities separated by a plurality of mesas. The plurality of dies is mounted to the substrate using the plurality of contacts. The underfill material is located between the substrate and the dies. The underfill material is localized into a plurality of regions using the mesas. Each of the contacts is located in a respective one of the cavities. In some embodiments, the substrate further includes a plurality of channels interconnecting the cavities. In some embodiments, the substrate further includes a plurality of intra-cavity mesas for further localizing the underfill material. In some embodiments, outer edges of a first one of the dies rest on first mesas located on edges of a first one of the cavities.