New glass compositions and applications thereof are disclosed. A glass composition as described herein can include 50 to 55 weight percent SiO.sub.2, 17 to 26 weight percent B.sub.2O.sub.3, 13 to 19 weight percent Al.sub.2O.sub.3, 0 to 8.5 weight percent MgO, 0 to 7.5 weight percent ZnO, 0 to 6 weight percent CaO, 0 to 1.5 weight percent Li.sub.2O, 0 to 1.5 weight percent F.sub.2, 0 to 1 weight percent Na.sub.2O, 0 to 1 weight percent Fe.sub.2O.sub.3, 0 to 1 weight percent TiO.sub.2, and 0 to 8 weight percent of other constituents. Also described herein are glass fibers formed from such compositions, composites, and articles of manufacture comprising the glass compositions and/or glass fibers.

A thermally conductive type polyimide substrate is provided. The substrate comprises at least one insulating layer having a metal layer on a single side or both sides thereof. The material of the insulating layer is a thermally conductive type photosensitive resin having a thermal conductivity of 0.4 to 2, and the thermally conductive type photosensitive resin includes the following components: (a) a photosensitive polyimide, (b) an inorganic filler, and (c) a silica solution. The photosensitive polyimide accounts for 50 to 70% of a total weight of a solid composition of the thermally conductive type photosensitive resin. The inorganic filler accounts for 20-30% of the total weight of the solid composition of the thermally conductive type photosensitive resin, and has a particle size between 40 nm and 5 m. The silica solution comprises silica particles polymerized by a sol-gel process, and the silica particles have a particle size between 10 nm and 15 nm and account for 5 to 30% of the total weight of the solid composition of the thermally conductive type photosensitive resin.

A circuit board according to an embodiments includes an insulating portion comprising a plurality of insulating layers, wherein the insulating portion includes: a first insulating portion; a second insulating portion disposed on the first insulating portion and having a coefficient of thermal expansion corresponding to the first insulating portion; and a third insulating portion disposed under the first insulating portion and having a coefficient of thermal expansion corresponding to the first insulating portion; wherein the first insulating portion includes a prepreg including glass fibers, and wherein the second and third insulating portions include a resin coated copper (RCC) with a coefficient of thermal expansion in the range of 10 to 65 (10.sup.?6 m/m.Math.k).

A resin composition contains a maleimide compound (A), a cyanate ester compound (B), a polyphenylene ether compound (C) with a number average molecular weight of not lower than 1000 and not higher than 7000 and represented by Formula (1), and a block copolymer (D) having a styrene backbone. In Formula (1), X represents an aryl group; (YO)n.sub.2- represents a polyphenylene ether moiety; R.sub.1, R.sub.2, and R.sub.3 each independently represent a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group; n.sub.2 represents an integer of from 1 to 100; n.sub.1 represents an integer of from 1 to 6; and n.sub.3 represents an integer of from 1 to 4. ##STR00001##

The disclosure concerns polymer compositions exhibiting LDS properties while maintaining mechanical properties and a dark color throughout the composition.

An object of the present invention is to provide a resin composition that can attain cured products having high flame retardancy, high heat resistance, a small coefficient of thermal expansion, and high drilling processability, a prepreg having the resin composition, a laminate and a metal foil clad laminate having the prepreg, and a printed circuit board having the resin composition. A resin composition, having at least an epoxy silicone resin (A) prepared by reacting a linear polysiloxane (a) having a carboxyl group with a cyclic epoxy compound (b) having an epoxy group such that the epoxy group of the cyclic epoxy compound (b) is 2 to 10 equivalents based on the carboxyl group of the linear polysiloxane (a), a cyanic acid ester compound (B) and/or a phenol resin (C), and an inorganic filler (D).

New glass compositions and applications thereof are disclosed. A glass composition as described herein can include 50 to 55 weight percent SiO.sub.2, 17 to 26 weight percent B.sub.2O.sub.3, 13 to 19 weight percent Al.sub.2O.sub.3, 0 to 8.5 weight percent MgO, 0 to 7.5 weight percent ZnO, 0 to 6 weight percent CaO, 0 to 1.5 weight percent Li.sub.2O, 0 to 1.5 weight percent F.sub.2, 0 to 1 weight percent Na.sub.2O, 0 to 1 weight percent Fe.sub.2O.sub.3, 0 to 1 weight percent TiO.sub.2, and 0 to 8 weight percent of other constituents. Also described herein are glass fibers formed from such compositions, composites, and articles of manufacture comprising the glass compositions and/or glass fibers.

A printed circuit board includes an insulating layer, and a first wiring layer at least partially embedded in one surface of the insulating layer, one surface of the first wiring layer being exposed from the one surface of the insulating layer. The insulating layer includes a first insulating layer covering at least a portion of a side surface of the first wiring layer, and a second insulating layer disposed on the first insulating layer and the first wiring layer, and the first and second insulating layers include different insulating materials.

A conductive pattern formation method of the present invention includes a first exposure step of radiating active light in a patterned manner to a photosensitive layer including a photosensitive resin layer provided on a substrate and a conductive film provided on a surface of the photosensitive resin layer on a side opposite to the substrate; a second exposure step of radiating active light, in the presence of oxygen, to some or all of the portions of the photosensitive layer not exposed at least in the first exposure step; and a development step of developing the photosensitive layer to form a conductive pattern following the second exposure step.

A method of manufacturing a patterned conductor is provided, comprising: providing a substrate, comprising: a base material with an electrically conductive layer disposed thereon; providing an electrically conductive layer etchant; providing a spinning material, comprising: a carrier; and, a photosensitive masking material; providing a developer; forming a plurality of masking fibers and depositing them onto the electrically conductive layer to form a plurality of deposited fibers; patterning the plurality of deposited fibers to provide a treated fiber portion and an untreated fiber portion; developing the plurality of deposited fibers, wherein either the treated fiber portion or the untreated fiber portion is removed, leaving a patterned fiber array; contacting the electrically conductive layer to the electrically conductive layer etchant, wherein the electrically conductive layer that is uncovered by the patterned fiber array is removed, leaving a patterned conductive network on the substrate.