Adequate die-to-lead frame adhesion is necessary for lead-on-chip (LOC) package integrity during and after the manufacturing process. Inadequate adhesion may result in a variety of defects such as die adhesion failure, marginal wire bond, broken wire, and bent leads, which ultimately lead to electrical failure [Mallik, US Patent No. 4,835,120 (May 1989); M. Amagai and E. Kawasaki, Mater. Res. Symp. Proc. 338, 185 (1994)]. Adhesion between the LOC tape and the polyimide passivation is affected by the surface properties of both materials. Understanding the relationships between these properties helps engineers eliminate inadequate adhesion at die attach and continuously improve the manufacturing process. To this end, die that exhibit inadequate adhesion at die attach are analyzed and compared with die that exhibit adequate adhesion characteristics. To focus on the surface chemistry and physical properties of the passivation layer, x-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, atomic force microscopy (AFM), and surface energy are used. Molecular concentrations and orientations are investigated and related to inadequate adhesion at die attach.