A flexible printed circuit board according to the present disclosure includes: a first base sheet, a second base sheet, and a first protection sheet. The first base sheet includes a first Teflon film and a first circuit pattern disposed on the first Teflon film. The second base sheet includes a second Teflon film and a second circuit pattern disposed on the second Teflon film, and is laminated on the first base sheet. The first protection sheet covers the first base sheet. A portion of the first base sheet that is exposed to the first protection sheet is surface-modified.

A multi-layer coating on an outer surface of a substrate includes a first layer applied directly to the outer surface of the substrate. The first layer includes diamond-like carbon (DLC) configured to mitigate metal whisker formation. A second layer is applied on a top surface of the first layer. The second layer is a conformal coating that includes a second material configured to bind to the top surface of the first layer and fill any microfractures that may form in the first layer. Optionally, a third layer is applied on a top surface of the second layer and includes DLC configured to protect the second layer from oxidation and degradation.

A heat radiating substrate (10) (circuit board) includes: an insulating layer (11) (insulating substrate); and a circuit pattern (20) of a metal provided on the insulating layer (11) in direct contact with the insulating layer (11), in which the circuit pattern (20) has a first circuit pattern formed in a first region on the insulating layer (11) and a second circuit pattern (120) formed in a second region on the insulating layer (11), and the first region (that is, the first circuit pattern) surrounds and closes the second region (that is, second circuit pattern (120)) when viewed in a top view.

A multilayer board includes laminates. Each of the laminates includes a liquid crystal polymer substrate and a metal layer. Each of the liquid crystal polymer substrates has a melting point. When a number of the liquid crystal polymer substrates is an odd number, they include a first middle substrate that is located in the most middle position and has a first melting point lowest among the melting points. The melting points increase in a direction away from the first middle substrate. When the number of the liquid crystal polymer substrates is an even number, they include second and third middle substrates that are located in the most middle position and respectively have second and third melting points that are substantially same. The second or third melting point is lowest among the melting points. The melting points increase in a direction away from the second and third middle substrates.

The polyimide resin precursor in the present embodiment is a polyimide resin precursor obtained by allowing a diamine component and a tetracarboxylic acid anhydride component to react with each other, wherein based on the whole of the diamine component, the content of p-phenylenediamine is 75 mol % or more; the tetracarboxylic acid anhydride component includes an ester-containing tetracarboxylic acid anhydride represented by formula (1), and at least one biphenyltetracarboxylic acid anhydride selected from the group consisting of 3,4,3′,4′-biphenyltetracarboxylic acid dianhydride, 2,3,3′,4′-biphenyltetracarboxylic acid dianhydride and 2,3,2′,3′-biphenyltetracarboxylic acid dianhydride; and based on the whole of the tetracarboxylic acid anhydride component, (i) the total of the content of the ester-containing tetracarboxylic acid anhydride and the content of the biphenyltetracarboxylic acid anhydride is 75 mol % or more, and (ii) the content of the ester-containing tetracarboxylic acid anhydride is 15 to 80 mol %, and the content of the biphenyltetracarboxylic acid anhydride is 85 to 20 mol %.

A method for mounting an electronic component on a resin base material, the method including: (1) preparing the resin base material having a wiring pattern formed of a conductive paste; (2) supplying a solder paste which contains solder particles and a thermosetting resin in a state before curing to a predetermined portion of the resin base material; (3) placing the electronic component on the solder paste; and (4) heating the resin base material to heat the solder paste to a temperature in a range from 105° C. to 130° C., inclusive to melt the solder particles, and starting a curing exothermic reaction of the thermosetting resin, wherein a melting temperature of the solder particles is in a range from 90° C. to 130° C., inclusive, and a peak temperature of the curing exothermic reaction of the thermosetting resin is in a range from 135° C. to 165° C., inclusive.

A flexible electronic device (SED) that can conform to a three-dimensional structure, and methods for manufacturing the SED, are disclosed herein. The SED comprises a flexible substrate which is modified in accordance with a folding pattern. The flexible substrate can be folded or unfolded along crease lines of the folding pattern, and the largest deformations of the substrate are localized at the crease lines. Various functional components of the SED are positioned on rigid regions of the substrate defined by the folding pattern. Such that the various functional components are protected from large deformations due to a folding or unfolding process, ensuring good performance of the functional components.

Provided is a printed circuit board which includes: a first dielectric layer including a first principal surface and a second principal surface on a side opposite to the first principal surface; a first adhesive layer formed on the first principal surface; a first metal foil pattern formed on the first adhesive layer and forming a signal line; and a second metal foil pattern formed on the second principal surface and forming a ground layer, in which the first metal foil pattern has a higher specific conductivity than a specific conductivity of the second metal foil pattern.

[Object]

To provide a copper clad laminate that is capable of achieving high adhesion between a low dielectric resin film and a copper plating layer and a good volume resistivity while suppressing a transmission loss when being applied to a flexible circuit board, and a method for producing the copper clad laminate.

[Solving Means]

A copper clad laminate of the present invention includes a low dielectric resin film having a relative permittivity of 3.5 or lower and a dissipation factor of 0.008 or lower at a frequency of 10 GHz, and an electroless copper plating layer laminated on at least one surface of the low dielectric resin film. A weighted average size of crystallites in the electroless copper plating layer is 25 to 300 nm, and an adhesion strength between the resin film and the electroless copper plating layer is 4.2 N/cm or more.

The present disclosure relates to a fluororesin substrate laminate for a high-frequency circuit, the fluororesin substrate laminate including a fluororesin substrate and an adhesive layer provided on the fluororesin substrate, wherein the adhesive layer includes a resin composition containing: (A) a maleimide compound having a saturated or unsaturated divalent hydrocarbon group; and (B) an aromatic maleimide compound.