A New Photoreactive Poly(aryl ether ketone) with a Low Dielectric Constant

Poly(aryl ether ketone) (1) containing alkyl groups was prepared by nucleophilic substitution of 4,4'-difluorobenzophenone (DFBP) with 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane (TMBPA). And co-poly(aryl ether ketone) (2) containing heterocyclic moiety was prepared from DFBP, TMBPA, and 2,6-dichrolopyridine (DCP). The polymers were soluble in common organic solvents, such as N-methyl-2-pyrroridone, tetrahydrofurane, chloroform, and cyclopentanone at room temperature. Thermogravimetry of the polymers showed good thermal stability, indicating that a 5% weight loss of the polymer (1) and (2) were observed at 421degreesC and 395degreesC in air respectively. Glass transition temperature of the polymers ranged from 206 to 212degreesC. Transparency of the polymers at 365 nm was almost 40-50%. The polymers showed low water absorption of 0.1-0.2%. The polymers acted as a negative-working photoreactive polymer by UV radiation. Adhesion to copper substrate of the polymer (2) was improved compared with the polymer (1). Then the polymer (2) was capable to resolve a 20 mum phi hole pattern on copper plating sur-face when a 10 mum-thick film was used The dielectric constant and dissipation factor of the polymer (2) were 2.71 and 0.0043 at 12 GHz respectively.