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Liquid Crystalline Thermosets As Materials For Microelectronics

Published online by Cambridge University Press:  15 February 2011

C. K Ober and
G. G. Barclay
C. K Ober
Affiliation:
Materials Science & Engineering, Bard Hall, Cornell University, Ithaca, NY 14853–1501
G. G. Barclay
Affiliation:
Materials Science & Engineering, Bard Hall, Cornell University, Ithaca, NY 14853–1501
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Abstract

New liquid crystalline thermosets have been prepared from end-functional monomers and oligomers of varying molecular weight. Both triazine and epoxy networks were explored. Of primary interest was the exploitation of the mesophase properties of these networks for developing polymers with high thermal stability and low coefficients of thermal expansion (CTE). Curing was carried out either within the nematic mesophase or the isotropic phase of the prepolymers. Transition temperatures associated with the mesophase were observed to change after curing under these two sets of conditions. The networks with the highest crosslink density were found to exhibit the lowest CTE values. Crosslinking of these thermosets was also carried out in the presence of a 13.5 Tesla magnetic field to determine the effect of orienting fields on the curing of the LC network. Orientation parameters as measured by wide angle x-ray diffraction were as high as 0.6. Values of the coefficient of thermal expansion as low as 15 ppm were achieved in the aligned direction. Of the two resin types, those with the triazine crosslinks had the lowest thermal expansion coefficient. Other thermal properties of these networks will be discussed.

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References

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