Soluble Polyimides Containing Benzimidazole Rings for Interlevel Dielectrics

Abstract

New soluble polyimides with improved adhesion to copper were synthesized from 6,4‘-diamino-2-phenylbenzimidazole (BIA) and 2,2‘-bis(trifluoromethyl)-4,4‘-diaminobiphenyl (TFDB) with 3,3‘,4,4‘-benzophenone tetracarboxylic dianhydride (BTDA) via one-pot synthetic method using N-methylpyrrolidone (NMP) as a solvent. Precipitation or gelation did not occur during imidization, and the synthesized polyimides having inherent viscosity values of 0.86−1.74 dL/g were dissolved well in polar aprotic solvents and phenolic solvents. Flexible and fingernail-creasable films were formed on casting. T g values of the polyimides were in the range of 320−351 °C and 5% weight loss in nitrogen occurred above 540 °C in all cases. The polyimides containing an equimolar amount of BIA and TFDB showed good adhesion to copper without any adhesion promoters. Water absorption and dielectric constant of the polyimides were in the ranges of 0.57−1.18% and 2.74−2.94, respectively. The polyimides containing a higher content of benzimidazole rings exhibited higher adhesion to copper.

Preparation and properties of heat-sealable polyimide films with comparable coefficient of thermal expansion and good adhesion to copper matrix

“…PI-4 and PI-5 containing benzimidazole moiety exhibited the highest adhesion to copper foil with the peeling strength higher than 1.0 N/mm. Actually, it has been known that incorporation of primary or secondary amine groups, which can interact with copper, into PIs could enhance their adhesion [20]. This result is in good agreement with the literature data.…”

“…The current APBI-containing PI-4 exhibited lower CTE value as compared with its soluble analogue reported in the literature, such as those derived from 4APBI, 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl (TFDB), and 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA) (CTE:29.6-55.3 ppm/°C) [20]. The main defect for PI-4 is its high sealing temperature, which might deteriorate the properties of the copper foil.…”

Preparation and characterization of imide-grafted poly(ethersulfone)s

“…but the small decrease of ε in IPES20 and IPES40 compared with PES might come from complex structural polarization effects of those polymers and correlates with the report that polyetherimide such as Ultem TM has slightly smaller ε value (3.00 at 1 KHz) compared with polyethersulfone such as Udel TM (3.07 at 1 KHz). 20 While Ultem TM has imide groups in polyarylether backbones, IPES20, IPES30, and IPES40 have imide groups in the pendent and are expected to behave much 'PES-likely' rather than 'Polyimide-likely'. [21][22][23] In addition, the decreased birefringence (∆n) of IPES20, IPES30, and IPES40 also match with the expectation that incorporated pendent imide groups reduce any chain packing of PES and increases free volumes of resulting polymers.…”

New soluble polyamides and polyimides containing polar functional groups: pendent pyrazole rings with amino and cyano groups

“…[4][5][6][7][8] For example, polyamides and polyimides containing trifluoromethyl groups show a high modulus, a low thermal expansion coefficient as well as good solubility, [9][10][11][12][13][14][15][16][17][18][19][20][21] and the incorporation of heterocyclic units into polyimide chains increases the glass transition temperature and thermal stability. [22][23][24][25][26][27] Also, soluble polyamides and polyimides containing crosslinkable pendent groups represent useful methods in many applications. [28,29] Introducing stable functional groups as substituents is interesting because they can be used to impart special functionalities to polymers and to improve their processability.…”