Abstract:
[Problem] To provide a highly-reliable circuit board and an electronic device obtained by mounting electronic components on the circuit board, which have high bonding strength and excellent heat discharge properties, and can be used over a long period as a result of minimizing cavities in a metal wiring layer formed on a through conductor. [Solution] A circuit board (10) is provided with a through conductor (13) comprising a metal in a through hole (12) that penetrates in the thickness direction of a ceramic sintered body (11), and a metal wiring layer (14) that covers and is connected to the surface of the through conductor (13) on at least one main surface side of the ceramic sintered body (11). The through conductor (13) comprises: a first area (13a) that is positioned on an inner wall side of the through hole (12), from one end to the other end of the through hole (12) in the thickness direction of the ceramic sintered body (11); and a second area (13b) that adjoins the first area (13a). The average crystal grain size in the second area (13b) is larger than the average crystal grain size in the first area (13a).
Abstract:
PROBLEM TO BE SOLVED: To provide a formation method of copper wiring capable of improving copper wiring conductivity and suppressing degradation caused by aging, a manufacturing method of a wiring board, and the wiring board.SOLUTION: A formation method of copper wiring comprises: a pattern formation step of applying a first dispersion liquid 12 in which first copper particles 14 with a particle size of 100 nm or above are dispersed to a board 10 to form a wiring pattern on the board 10; a drying step of drying the wiring pattern at a temperature less than 150°C; an application step of applying a second dispersion liquid 16 in which second copper particles 18 having a particle size smaller than the particle size of the first copper particles 14 are dispersed to the same position as the wiring pattern after the drying step; a densification step of filling a gap between the first copper particles 14 and the second copper particles 18 of the wiring pattern after the application step; a heating step of heating the wiring pattern after the densification step; and a reduction processing step of reducing the wiring pattern after the heating step. There are also provided a manufacturing method of a wiring board and the wiring board.
Abstract:
PROBLEM TO BE SOLVED: To provide a photosensitive composition excellent in defoaming property and cissing property when being coated on a member to be coated on.SOLUTION: The photosensitive composition contains a polymerizable polymer having a carboxyl group, a photopolymerization initiator, titanium oxide, a first silica, a second silica and a polydimethylsiloxane. The primary particle diameter of the first silica is ≥5 nm and ≤100 nm. The primary particle diameter of the second silica is ≥0.5 μm and ≤10 μm. The photosensitive composition, if the viscosity (mPa s) at a shearing rate of 1 rpm at 25°C is taken as η1 and that at a shearing rate of 10 rpm at 25°C is taken as η10, has a viscosity ratio (η1/η10) of ≥1.1.
Abstract:
To provide a magnetic substance-containing insulator that can achieve an effect of increasing the permeability without comparatively increasing the mixing concentration of a magnetic substance and, by applying the thus obtained magnetic substance-containing insulator to a circuit board, that can improve the characteristic impedance and achieve an effect of reducing the power consumption, and to provide a circuit board and an electronic component each using such a magnetic substance-containing insulator. A magnetic substance-containing insulator 10 includes plural magnetic substance particles 1a, 1b and an insulator 2 holding the plural magnetic substance particles 1a, 1b, wherein a group of the magnetic substance particles is composed of plural particle sizes.