Properties of Phosphorus-Containing Poly(imide – siloxane) Hybrid Films Applied in Flexible Copper Clad Laminate

• Main Authors: HSIEH, TSUNGTA, 謝宗達
• Other Authors: TSAI, MEIHUI
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/58449608285677008772

碩士 === 國立勤益科技大學 === 化工與材料工程系 === 100 === This study is divided into two parts. First, the phosphorus-containing diamine monomer (DMA), non-phosphorus-containing diamine monomer (ODA) and the flexible dianhydride monomer (IDPA) were selected to synthesize polyimide (PI) films containing various ratios of diamines. The PI film derived from 100% of DMA (10D) showed the characteristic absorption peak of phosphorus (P-O-Ph) at 914 cm-1 from the Fourier transform infrared (FTIR) spectra. Another observed peak at 1180 cm-1 belongs to the characteristic absorption peak of P-OH on polyphosphate indicating the generation of the polyphosphate on the PI surface.The depth profile of X-ray photoelectron spectra (XPS) in the phosphorus region also shows the polyphosphate P-OH on the surface with the binding energy at 132 eV. The phosphorus PI film (10D) has the highest storage modulus of 2445 MPa and the highest glass transition temperature (Tg) of 276 oC. The coefficient of thermal expansion (CTE) of 10D film is 48 ppm/oC, compared with66 ppm/oC for the PI film containing only ODA (10O). The 5% weight loss temperature (Td5) slightly decreases with the increasing proportion of phosphorus in PI matrix. The Td5 of 10D film is 430 oC. The optical transparency at 400 nm of PI films with the thickness of 25 μm increases with the phosphorus content. The transmission of 10D film is 70% and the dielectric constant of 10D film decreases to 2.7. The adhesion test of PI films with flexible copper foil(1oz ED copper) showed that the PI film containing 80% of DMA (8D2O) has the highest peel strength of 0.51 Kg/cm. The polarizing microscope was used to compare the amount of resin flow between copper and PI after adhesion test. The amount of resin flow significantly reduces as the phosphorus content increases in PI matrix. In the second part, the ODA in the 8D2O PI film was substituted by polydimethylsiloxane (PDMS) in order to further improve the adhesion strength. The diamine monomer ODA (1 to 8 wt%) in 8D2O film was substituted by PDMS, which has the diamine functional groups, to prepare the hybrid films (8D2O-Si-x%). The FT-IR spectra confirm the presence of Si-C (1260 cm-1, 800 cm-1) and Si-O (1080 cm-1, 1020 cm-1) characteristic absorption peaks in the hybrid films. The XPS results also show Si-C (102.3 eV) and Si-O (101.1eV) peaks indicating the successful blending of PDMS in PI. The mechanical strength of hybrid films decreased with the PDMS content because PDMS is a soft monomer. For 8D2O-Si-8% hybrid film, its storage modulus is 2135 MPa, Tg is 256 oC, CTE is 82 ppm/oC and Td5 is 435 oC. The optical transmission at 400 nm of this film is only 63%. PDMS forms discontinuous phases in PI andthus the light penetration is restricted. The silicon in PDMS increases the dielectric constant of the 8D2O-Si-1% film to 3.7. In contrast, the presence of PDMS can effectively reduce the moisture absorption. Hence, the dielectric constant of the 8D2O-Si-8% film further reduces to 3.0. , The peel strength of 8D2O-Si-8% film increases to 0.95 Kg/cm.The comparison of the resin flow conditions between 8D2O-Si-8% and pure-Si-8% again confirme that less amount of resin flow is achieved by the presence of phosphorus in PI.