Studies of dielectric characteristics and surface energies of spin‐coated polyimide films

Abstract

A two-step method, that is, polyamic acid formation with subsequent curing, was used to synthesize six kinds of polyimides. Dielectric constants and surface energies were investigated to determine the nature of the fluorinated and nonfluorinated polyimides. The dielectric constant decreased from 3.3 (at 100 kHz) for PMDA/ ODA to 2.6 (at 100 kHz) for 6FDA/4,4Ј-6F when the fluorine content increased from 0 to 30.7 wt %. Simultaneously, the water contact angle increased from 65°for PMDA/ ODA to 78°for 6FDA/4,4Ј-6F. Experimental results indicated that fluorinated polyimides contained a lower dielectric constant with improved water resistance. The surface energy values obtained from experiments agreed well with Holmes' correlation between surface energy and dielectric constant. The surface energies and dielectric constants were significantly affected by the polymer backbone structures, especially by the fluorination effect. Therefore, by choosing the appropriate monomers, polyimides of low dielectric constants with hydrophobic surfaces could be obtained.

Revealing the correlation between molecular structure and dielectric properties of carbonyl‐containing polyimide dielectrics

“…[18][19][20][21][22][23][24][25][26][27] The polar groups functioned as permanent dipoles would be beneficial to the enhancement of dielectric constant. 31 Similar results happened in Chisca's research. [28][29][30] However, the dielectric constant of polyimide (i.e., commercial polyimide of Kapton, 3.1) should be further enhanced.…”

A study of atmospheric-pressure CHF3/Ar plasma treatment on dielectric characteristics of polyimide films

“…Surface modification of polyimides by the use of ion beams and plasma treatment is considerably important in both technology and science [2,7,[9][10][11][12][13]. These methods have been utilized successfully to improve the dielectric properties of polyimide films.…”

“…Aging effects depend on external influences such as adsorption or oxidation and on the internal tendency to attain an energetically favorable state (thermodynamic equilibrium) by restructuring processes and diffusion. A high-energy surface is prone to adsorb contaminants from the atmosphere in order to lower its surface energy [4,[11][12][13][14].…”

A study on dielectric characteristics of fluorinated polyimide thin film

“…Consequently, C-F bonds have relatively stronger than other C-X bonds. Therefore, the intensity of carbon-fluorine groups is increased as a function of the treatment gas [11][12][13][14][19][20][21]. Fig.…”

“…This can be attributed to the following three effects: changes in hydrophobicity, changes in free volume, and changes in total polarizability. The lowest dielectric constant is due to a combination of all three factors [11][12][13][14][15][16].…”