Preparation and characterization of quartz‐fiber‐cloth‐reinforced, polymerization‐of‐monomer‐reactant‐type polyimide substrates with a high impact strength

Abstract

A series of novel quartz-fiber-cloth-reinforced polyimide substrates with low dielectric constants were successfully prepared. For this purpose, the A-stage polyimide solution was first synthesized via a polymerization-of-monomer-reactant procedure with 2,2 0 -bis(trifluoromethyl)benzidine and 3,3 0 ,4,4 0 -oxydiphthalic anhydride as the monomers, and cis25-norbornene-endo-2,3dicarboxylic anhydride as the endcap. Then, an A-stage polyimide solution (TOPI) was impregnated with quartz-fiber cloth (QF) to afford the prepregs, which were thermally molded into the final substrate composites. The influence of the curing temperature and the resin content on the mechanical properties of the composite were examined. The composites exhibited a high glass-transition temperature over 3608C, a low and steady dielectric constant below 3.2 at a test frequency of 1-12 GHz, and a volume resistance over 1.8 3 10 17 X cm. Meanwhile, they also showed a high mechanical strength with flexural and impact strengths in ranges 845-881 MPa and 141-155 KJ/m 2 , respectively. The excellent mechanical and thermal properties and good dielectric properties indicated that they are good candidates for integrated circuit packaging substrates.

Quartz fiber cloth-reinforced semi-aromatic thermosetting polyimide composite with high-frequency low dielectric constant

“…This may be predominantly because that the continuous quartz fiber account for lower CTE xy in the direction parallel to the quartz cloth, whereas the high CTE z in the direction perpendicular to the quartz cloth results from the combined influence of quartz cloth and interlayer resin. 36 The high T g and excellent thermal reliability of QF/PI-4 are expected to meet the requirements of high processing and application temperatures in the high-frequency IC boards industry. Additionally, the bending strength and interlaminar shear strength of QF/PI-4 composites are 645 and 90 MPa as shown in Figure 8(d).…”

“…Therefore, the alicyclic HPMDA with less π bonds and conjugated electron can prevent the electron cloud from being effectively polarized. Additionally, the noncoplanar and twisted structure of HPMDA disrupt the close packing of polymer chains and endow the as-prepared semi-aromatic PI with high free volumes, 36 which also contribute to the low D k and D f . As shown in Figure 10(b), at a high frequency of 1–12 GHz, the D k of QF/PI-4 is stable in the range of 3.16–3.2, and the D f is stable in the range of 0.0026–0.0046.…”

“…In fact, it was a solution mixture of several kinds of salts. 36 The molar ratio of NA to HPMDA to diamines (DMBZ and BAPP) was 2:n:(n þ 1). The theoretical molecular weights of each PI resins were fixed to 2500 g mol À1 by adjusting the values of n. The abbreviations of these thermosetting PI samples with different molar ratio of DMBZ/BAPP are listed in Table 1.…”

Improving the Dimensional Stability of Polyphenylene Oxide without Reducing Its Dielectric Properties for High-Frequency Communication Applications

“…The most convenient way to do this is introducing a crosslinking agent with large groups, such as a trifluoromethyl group with large free volume, small dipole, and low polarization. 25,26 But the conventional crosslinking agents contain only small groups such as allyl and epoxy groups. Crosslinking agents with allyl and trifluoromethyl groups at the same time have not been reported yet.…”

Low‐dielectric‐constant aromatic homopolyimide and copolyimide derived from pyromellitic dianhydride, 4,4′‐oxydianiline, 2,2‐bis[4‐(4‐aminephenoxy)phenyl]propane, 1,4‐bis(4‐aminophenoxy)benzene, or 1,3‐bis(4‐aminophenoxy)benzene

“…The dielectric constant of polyimide decreased significantly from 3.1 to below 2 with fluoridized diamine monomers or dianhydride acid monomers. Despite the fact that many researchers have paid attention to fluorinated polyimide because of its outstanding dielectric performance, fluorinated polyimide also has its disadvantages, including a greatly reduced decomposition temperature from above 500 to 200 °C, the fact that the addition of filler retained the tensile strength of a nonfluorinated polyimide, and the use of a complex preparation process but a low and steady dielectric constant below 3.2 at 1–12 GHz.…”