A porous polyimide film is provided to suppress an increase in a dielectric loss tangent even when immersed in water. In the porous polyimide film, a difference between a dielectric loss tangent T1 after being left to stand for 24 hours under an atmosphere of 25° C. and relative humidity of 50% and a dielectric loss tangent T2 after immersion in water for 24 hours under an atmosphere of 25° C. is 0.0030 or less.

A resin composition and uses of the same are provided. The resin composition includes the following components: (A) a cross-linking agent of the following formula (I):

##STR00001## (B) a polyphenylene ether resin, wherein the terminal ends of the polyphenylene ether resin are independently modified by a substituent with a carbon-carbon double bond; and (C) a catalyst, wherein, X in formula (I) is a C.sub.1 to C.sub.10 straight or branched alkylene, and the weight ratio of the polyphenylene ether resin (B) to the cross-linking agent (A) ranges from 0.5 to 5.

Provided is a resin composition which has good solubility and photocurability, further has good alkaline-developability when containing a photo initiator and a compound containing one or more carboxyl groups, and in addition, is capable of providing a resin sheet having suppressed tackiness; and a resin sheet, multilayer printed wiring board, and semiconductor device using the same. The resin composition of the present invention contains a particular bismaleimide compound (A), and at least two maleimide compounds (B) selected from the group consisting of six kinds of particular compounds which are different from this bismaleimide compound (A).

In a first aspect, a polyimide film includes a polyimide derived from a dianhydride and a diamine. The dianhydride includes pyromellitic dianhydride, the diamine includes a benzimidazole, the molar ratio of dianhydride to diamine that forms the polyimide is in a range of from 0.85:1 to 0.99:1, and the polyimide film has a T.sub.g of 400° C. or higher, a tensile modulus of 6.0 GPa or more, and a coefficient of thermal expansion of 15 ppm/° C. or less over a temperature range of 50 to 500° C. In a second aspect, an electronic device includes the polyimide film of the first aspect.

The present invention relates to a method for producing a flexible substrate. According to the method of the present invention, a flexible substrate layer can be easily separated from a carrier substrate even without the need for laser or light irradiation so that a device can be prevented from deterioration of reliability and occurrence of defects caused by laser or light irradiation. In addition, according to the method of the present invention, a flexible substrate can be continuously produced in an easier manner based on a roll-to-roll process.

A polyamic acid as a polymer of a dianhydride monomer and a diamine monomer is disclosed. The dianhydride monomer is an aromatic tetrabasic carboxylic acid dianhydride monomer. The diamine monomer comprises a diamine monomer containing pyrimidinyl and an aromatic diamine monomer. A polyimide, a polyimide film and a copper clad laminate using the polyamic acid are also provided.

A connection structure configured to connect a display panel and a circuit board, includes a flexible printed circuit, a first chip-on-film, and a second chip-on-film. The first chip-on-film and the second chip-on-film are coupled to one end of the flexible printed circuit. The first chip-on-film and the second chip-on-film are coupled to two surfaces of the flexible printed circuit that are opposite in a thickness direction of the flexible printed circuit.

A benzoxazine resin, including a compound of the following Formula 1-1:

##STR00001##

where R.sup.1, R.sup.2, and R.sup.3 are as defined herein.

The purpose of the present invention is to provide: a novel triazole silane compound and a method for synthesizing the same, and a silane coupling agent containing the triazole silane compound as a component; and a surface treatment solution, a surface treatment method, and a method for bonding two different materials, which use said triazole silane compound.

A substrate for a printed circuit board according to an embodiment of the present invention includes a base film having an insulating property, and a conductive layer formed on at least one of surfaces of the base film. In the substrate for a printed circuit board, at least the conductive layer contains titanium in a dispersed manner. The conductive layer preferably contains copper or a copper alloy as a main component. A mass ratio of titanium in the conductive layer is preferably 10 ppm or more and 1,000 ppm or less. The conductive layer is preferably formed by application and heating of a conductive ink containing metal particles. The conductive ink preferably contains titanium or a titanium ion. The metal particles are preferably obtained by a titanium redox process including reducing metal ions using trivalent titanium ions as a reducing agent in an aqueous solution by an action of the reducing agent.