Adhesion and lamination testing of langley research center-soluble imide (LaRC-SI) polyimide films

This study was investigated the development, evaluation, design and fabrication of the methodology of self-adhesion by melt-bonding multilayers of Langley Research Center- Soluble Imide (LaRC-SI) polyimide films that are employed in the fabrication of multi- layer flexible circuits. Previous efforts at Langley Research Center have had successful bonding results, however there has been little time and effort to perform an adhesiveless-melt-bonding multiple layers of film into one homogeneous material. The understanding of the structure, property, and processing relationships on self-adhesion of LaRC-SI polyimide films is important to their proper design and methodology. The experiment was performed with the use of three commercial polyimide films, two types of LaRC-SI films, and with an addition of film to copper bonding test. The fully imidized LaRC-SI polyimide films was joined together in a self-adhesion lamination process to form a structure that is flexible and has superior mechanical and thermal properties. The lamination processing variables was investigated depending upon parameters such as autoclave temperature, pressure, soak time and final ply thickness. Control conditions included initial film thickness, sole-source manufacture, and lot number, and the percentage offset used to manufacture the LaRC-SI film The evaluation of the structure film bonding was investigated in LaRC laboratories using scanning electron microscopy and photomicrography for morphology study, followed by mechanical and peel tests that are defined by ASTM standards. The thermal characterizations were performed using differential scanning calorimetry, and thermal gravity analyzer. In addition, the electrical parameter measurements were performed including dielectric constant, dissipation factor, strength, and resistivity.