Polyimides anisotropic structure

Fourier transform infrared spectroscopy (FTIR) was also used to study the anisotropic structure of polyimide films. This work was based on the fact that there are characteristic absorptions associated with in-plane and out-of-plane vibrations of some functional groups, such as the carbonyl doublet absorption bands at 1700-1800 cm . The origin of this doublet has been attributed to the in-phase (symmetrical stretching) and out-of-phase (asymmetrical stretching) coupled... 

We have investigated many macroscopic properties of the organo-soluble aromatic polyimide films and all of them exhibit anisotropic behaviors which are closely associated with the anisotropic structure in the films. One question still remains is whether we can find a common physics background to describe these properties. If we consider the fi-ee energy (or internal energy or energy) term, the first derivative of... 

In summary, we have briefly reviewed our understanding in the development of organo-soluble aromatic polyimides via molecular design and architecture control and the establishment of relationships between the anisotropic structure and properties in the films. These anisotropic structures and properties are also found to be film thickness and molecular weight dependent. In particular, the LOA behavior has led to a invention where these aromatic polyimide films can be used as UNB retardation compensators in LCDs to increase viewing angles. This technology initiated from our researches has been commercialized to produce compensators for wide applications in LCDs,... 

Highly anisotropic copper-containing polyimide films have been produced through the homogeneous incorporation of bis(trifluoroacetyl-acetonato)copper(II), Cu(TFA), with the polyimide precursor followed by thermal cyclodehydration. By judious choice of polyimide precursor, doping level, and curing atmosphere two specific types of surface structure have been obtained. Bi- and tri-layered. 

Polyimide films are used in a variety of interconnect and packaging applications including passivation layers and stress buffers on integrated circuits and interlayer dielectrics in high density thin film interconnects on multi-chip modules and in flexible printed circuit boards. Performance differences between poly-imides are often discussed solely in terms of differences in chemistry, wiAout reference to the anisotropic nature of these films. Many of the polyimide properties important to the microelectronics industry are influenced not only by the polymer chemistry but also by the orientation and structure. Properties such as the linear coefficient of thermal expansion (CTE), dielectric constant, modulus, strength, elongation, stress and thermal conductivity are affected by molecular orientation. To a lesser extent, these properties as well as properties such as density and volumetric CTE are also influenced by crystdlinity (molecular ordering). 

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