A copper-clad laminate includes an insulating layer and a copper foil in contact with at least one surface of the insulating layer, in which the insulating layer contains a cured product of a resin composition containing a modified polyphenylene ether compound of which a terminal is modified with a substituent having a carbon-carbon unsaturated double bond, a chromium element amount on an exposed surface on which the insulating layer is exposed by an etching treatment of the copper-clad laminate with a copper chloride solution, measured by X-ray photoelectron spectroscopy is 7.5 at % or less with respect to a total element amount measured by X-ray photoelectron spectroscopy, and a surface roughness of the exposed surface is 2.0 μm or less in terms of ten-point average roughness.

A semiconductor device includes a circuit board including an insulating layer having opposite front and rear surfaces, an electrode pad disposed on the front surface, a housing having an installation area for the circuit board, and a bonding material embedded in a recess within either a first area located at the rear surface of the insulating layer directly below an area of the circuit board in which the electrode pad is disposed, or at a second area located within the installation area of the housing and corresponding to the first area in a plan view.

An electronic device such as a wearable electronic device may have a band. The band may form a stand-alone device or a strap for a wristwatch unit or other device. Electrical components may be mounted on flexible printed circuit substrates. A substrate may be encapsulated by elastomeric polymer material or other material forming the band. The elastomeric polymer material may form cavities that receive the electrical components. Components such as light-emitting diodes may be mounted to the flexible printed circuit substrates so that the light-emitting diodes are located in the cavities. Reflective sidewalls in the cavities may reflect light from the light-emitting diodes outwardly through a thinned portion of the band. Light-diffusing material in the cavities may be formed from clear polymer with light-scattering particles.

A method for preparing a PCB product having highly dense conductors, the method including providing a PCB substrate including a conductive layer, employing an inkjet printer to selectively print unexposed photosensitive patterns on the PCB substrate, the unexposed photosensitive patterns having a thickness of less than 5 pm, exposing the photosensitive patterns to radiation thereby to define exposed patterns, the exposed patterns having a pitch less than 20 pm and wet etching the conductive layer in accordance with a pattern defined by the exposed patterns thereby to define the highly dense conductors having a pitch of less than 30 pm.

The present invention relates to an etching solution composition for selectively etching only silver, a silver alloy, or a silver compound, and to a circuit forming method using the composition. The circuit forming method according to the present invention is characterized in that, in a substrate material in which an electrically conductive seed layer and a circuit layer are formed of heterogeneous metals, only the seed layer is selectively etched to enable the implementation of fine pitches. In addition, the present invention relates to a circuit forming method and an etching solution composition, wherein only a seed layer of silver (Ag), a silver alloy, or a silver compound is selectively etched without etching a copper (Cu) plated circuit.

The method includes providing a rigid base plate; forming an etch-stop layer on one side of the rigid base plate; forming a first flexible substrate on another side of the etch-stop layer; fabricating a plurality of stretchable circuits on the surface of the first flexible substrate facing away from the etch-stop layer; etching a first flexible substrate between two adjacent stretchable circuits to form a through hole; forming a first elastic layer that covers the plurality of stretchable circuits and fills the through hole; separating the rigid base plate and the etch-stop layer; and forming a second elastic layer opposite to the first elastic layer such that the plurality of stretchable circuits is encircled by the first and second elastic layers.

An aliphatic polycarbonate resin for forming a partition containing a constituent unit represented by the formula (1): ##STR00001##
wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are each independently a hydrogen atom, an alkyl group having one or more carbon atoms, an alkoxyalkyl group having two or more carbon atoms, an aryl group, or an aryloxyalkyl group; at least one of R.sup.1, R.sup.2, R.sup.3, and R.sup.4 is an alkyl group having two or more carbon atoms, an alkoxyalkyl group having two or more carbon atoms, an aryl group, or an aryloxyalkyl group; and R.sup.1, R.sup.2, R.sup.3, and R.sup.4 may be the same or different; and the aliphatic polycarbonate resin has a contact angle against water of 75° or more. Also disclosed is a partition material including the aliphatic polycarbonate resin, a substrate, a method of producing the substrate, a method for producing a wiring substrate, and a wiring forming method.

The present invention relates to an etching solution composition for selectively etching only silver, a silver alloy, or a silver compound, and to a circuit forming method using the composition. The circuit forming method according to the present invention is characterized in that, in a substrate material in which an electrically conductive seed layer and a circuit layer are formed of heterogeneous metals, only the seed layer is selectively etched to enable the implementation of fine pitches. In addition, the present invention relates to a circuit forming method and an etching solution composition, wherein only a seed layer of silver (Ag), a silver alloy, or a silver compound is selectively etched without etching a copper (Cu) plated circuit.

A component assembly includes a printed circuit board having an electronics component mounted on a first portion of a first face of the printed circuit board. A light emitting diode is mounted on a second portion of the first face. A light guide of a light transmissive polymeric material covers the body including the light emitting diode and the electronics component. The light guide includes: a cavity having the electronics component positioned within the cavity; a non-planar area of the light guide positioned above the cavity, the non-planar area mitigating against collapse of the light guide into the cavity; and a second cavity having the light emitting diode positioned within the second cavity; and a top plate of a polymeric light reflective material mounted onto the light guide directly above the light emitting diode.

A component assembly includes a printed circuit board having an electronics component mounted on a first portion of a first face of the printed circuit board. A light emitting diode is mounted on a second portion of the first face. A light guide of a light transmissive polymeric material covers the body including the light emitting diode and the electronics component. The light guide includes: a cavity having the electronics component positioned within the cavity; a non-planar area of the light guide positioned above the cavity, the non-planar area mitigating against collapse of the light guide into the cavity; and a second cavity having the light emitting diode positioned within the second cavity; and a top plate of a polymeric light reflective material mounted onto the light guide directly above the light emitting diode.