{Reference Type}: Journal Article
{Title}: Synthesis and Characterization of Negative-Tone Photosensitive Polyimides with Low Coefficient of Thermal Expansion for Packaging Applications.
{Author}: Zhang P;Wang H;Xia P;Chen X;Zhao W;Wang C;Meng X;Jia B;
{Journal}: Polymers (Basel)
{Volume}: 16
{Issue}: 13
{Year}: 2024 Jun 26
{Factor}: 4.967
{DOI}: 10.3390/polym16131805
{Abstract}: Negative-tone photosensitive polyimides (PSPIs) with a low coefficient of thermal expansion (CTE) were prepared by dissolving polyimide precursor-poly(amide ester) (PAE) resins, photoinitiators, photocrosslinkers and other additives in organic solvents. Using triamine as a monomer and dianhydride and diamine as polycondensates, tri-branched structure PAE resins with different molecular weights named PAE-1~5 were prepared. A series of corresponding PSPI films named PSPI-1~5 were prepared from PAE-1~5 resins with the same formulation, respectively. The PSPI-1~5 films prepared from resins of this structure have excellent mechanical, thermal and electrical properties after being thermally cured at 350 °C/2 h in nitrogen. The PSPI-1~5 films' coating solution also show good photolithographic performance and are able to obtain photolithographic patterns with a resolution of about 10 μm after homogenization, exposure and development. Among the PSPI-1~5 films, PSPI-2 has the most excellent lithographic properties with a weight average molecular weight (Mw) of 2.9 × 104 g/mol, a CTE of 41 ppk/°C, a glass transition temperature (Tg) of 343 °C and a 5% weight loss temperature (Td5) of 520 °C, making it suitable for industrial scale-up. The mechanical properties of elongation at breakage of 42.4%, tensile moduli of 3.4 GPa and tensile strength of 153.7 MPa were also measured.