Some embodiments contemplate methods for forming a package structure and a package structure formed thereby. An embodiment method includes depositing a photosensitive dielectric layer on a support structure; forming a first layer on a surface of the photosensitive dielectric layer; exposing the photosensitive dielectric layer to radiation; and after the forming the first layer and the exposing to radiation, developing the photosensitive dielectric layer. The support structure includes an integrated circuit die. The layer has a different removal selectivity than the photosensitive dielectric layer during the developing. According to some embodiments, a thickness uniformity of the photosensitive dielectric layer after developing may be increased, and thickness loss from developing the photosensitive dielectric layer can be reduced.