A covering film (100) includes a first covering layer (10), a first adhesive layer (20), and a thermal conductive layer (30) sandwiched between the first covering layer (10) and the first adhesive layer (20). A thermal conductivity of the thermal conductive layer (30) is K1, K1=3˜65 W/m.K. A thermal conductivity of the first covering layer (10) is K2, K2=0.02˜3.0 W/m.K. A thermal conductivity of the first adhesive layer (20) is K3, K3=0.02˜1.0 W/m.K. A circuit board and its manufacturing method are also provided.

A flexible circuit board includes liquid crystal polymer (LCP) layers and metal layers including circuit routes. Each of the LCP layers includes via structures. The metal layers and the LCP layers are alternatively stacked to form a multi-layer structure. Adjacent metal layers are electrically connected through the via structures. Some via structures of different LCP layers are substantially aligned with one another to form a stack of via structures. Each of the via structures includes openings filled with conductive material. The size of the opening fulfils the following equation: Vb≥cos(Bh/Vh)*Vt/k*2, where Vb is a diameter of a smaller aperture, Vt is a diameter of a bigger aperture, Vh is a combined thickness of a LCP layer and a metal layer, Bh is a thickness of a LCP layer and k is a tensile modulus.

A resin multilayer substrate includes a multilayer body including resin base-material layers laminated in a thickness direction and a circuit conductor therein, an end-surface ground conductor provided directly on each end surface of the multilayer body in the thickness direction, an adhesion layer on a side surface of the multilayer body, and a side-surface ground conductor on the adhesion layer. The end-surface and side-surface ground conductors are made of a ground conductor material with a coefficient of thermal expansion whose difference from a coefficient of thermal expansion of the resin base-material layers in a plane direction is smaller than a difference from a coefficient of thermal expansion of the resin base-material layers in the thickness direction. The adhesion layer is made of a material with higher adhesiveness to the side surface of the multilayer body than adhesiveness of the ground conductor material.

Forming, in a printed-wiring board, a via sufficiently filled without residual smear, for use in an insulating layer and the size of the via to be formed. A via of a printed-wiring board comprises a first filling portion which fills at least a center portion of a hole, and a second filling portion which fills a region of the hole that is not filled with the first filling portion. An interface which exists between the second and first filling portions, or an interface which exists between the second filling portion and an insulating layer and the first filling portion has the shape of a truncated cone comprising a tapered surface which is inclined to become thinner from a first surface toward a second surface, and an upper base surface which is positioned in parallel to the second surface and closer to the first surface than to the second surface.

A method includes providing a first laminate and a second laminate. The first laminate includes a first conductor layer, a first insulating layer containing polyimide, and a second conductor layer. The second laminate includes a second insulating layer containing polyimide and a third conductor layer. The method further includes: heating each of the first laminate and the second laminate under a condition including a heating temperature equal to or higher than 100° C. and a heating duration equal to or longer than half an hour; and stacking, after heating, the first laminate and the second laminate one on top of the other with a third insulating layer interposed between the second conductor layer and the second insulating layer.

A method for producing a panel with integrated conductor tracks and electronic components. The panel includes a panel body, wherein the panel body is in particular a sandwich structure, and a membrane. The membrane is connected to the panel body and has integrated conductor tracks and electronic components. At the beginning of the method, an operation for attaching the conductor tracks and the electronic components to the membrane is provided. The subsequent step includes an operation for connecting the membrane, fitted with the conductor tracks and the electronic components, to the panel body.

A reel-to-reel method to laser-ablate a circuitry pattern on the fly in a reel-to-reel machine as part of a process to fabricate a printed flexible circuit. The laser ablation method includes using an appropriate laser to irradiate a metal sheet thus ablating the edges of an intended circuitry pattern. Slugs can be removed by using an optional sacrificial liner, and the slugs can be optionally ablated into smaller parts first. The laser ablation can also include an optional method of creating tie bars to provide structural support to the web of circuitry patterns.

Wireless sensor devices are described which harvest energy and provide an antenna or antennas for wireless communication on a relatively small form factor, preferably one that is co-extensive with a largest component of the device, e.g., an antenna layer or sensor layer. The devices are able to sense and/or control certain specific parameters of a system; store energy, e.g., in a supercapacitor system or battery system; transmit that as information/signals via a wireless link, e.g., RF or optical link; receive information from other devices and relay that information. Such devices accordingly may be self-powered and wireless devices, and not dependent on a separate device or form factor to provide a power source. Such devices can be entirely autonomous or substantially so, can be mobile or fixed, and may require little servicing over a period of time. The devices can be used as sensor nodes in a wireless mesh network.

Research on practical realization of various types of printable devices has progressed, and the realization of devices in which these printable devices are integrated on a flexible board is expected. However, there is the problem that, if a plurality of printable devices are simply integrated on the same board, the area of the integrated device increases, and the yield ratio greatly decreases. An integration technique that solves the problem of an increase in the area and a decrease in the yield ratio is in demand. Electronic devices to be integrated are formed on individual boards, the boards are laid to overlap each other in a predetermined relationship, and then through-vias are formed at predetermined positions. With this, the electronic devices are electrically connected to each other, and function as an integrated device.

A multilayer resin substrate includes resin substrates laminated together, an overlapping portion in which a signal line as a conductor pattern and another conductor pattern overlap each other in a laminating direction of the resin substrates, and a non-overlapping portion in which the signal line and the other conductor pattern do no overlap each other in the laminating direction. A thin portion is provided at a position in the non-overlapping portion near the overlapping portion. The thin portion is a portion of the multilayer resin substrate which has a thickness smaller than the thickness in the overlapping portion in the laminating direction of the resin substrates.