Methods of forming microelectronic packaging structures and associated structures formed thereby are described. Those methods and structures may include forming a wafer level underfill (WLUF) material comprising a resin material, and adding at least one of a UV absorber, a sterically hindered amine light stabilizer (HALS), an organic surface protectant (OSP), and a fluxing agent to form the WLUF material. The WLUF is then applied to a top surface of a wafer comprising a plurality of die.