A method for producing a semiconductor package, capable of effectively suppressing contamination of a chemical liquid and unintended peeling-off of a reinforcing sheet, is provided. This method includes providing a tacky sheet including a substrate sheet, and a soluble tacky layer and a banking tacky layer on at least one surface of the substrate sheet; making a first laminate including a redistribution layer; using the tacky sheet to obtain a second laminate having a second support substrate bonded to a surface on the redistribution layer side of the first laminate with the tacky layer therebetween; peeling off the first support substrate, pretreating the resulting third laminate; mounting a semiconductor chip on a pretreated surface of the redistribution layer; immersing the third laminate in a solution to dissolve or soften the tacky layer; and peeling off the second support substrate in a state where the tacky layer is dissolved or softened.

A method of making a printed circuit board structure including a closed cavity is provided. The method can include the steps of forming a cavity in a core structure of a core layer, laminating each of a top surface and a bottom surface of the core structure with an adhesive layer and a metal layer to prepare a laminate structure and cover the cavity to define a closed cavity. The method also includes forming vias through the laminate structure, and patterning the metal layers in the laminate structure.

A method of making a printed circuit board structure including a closed cavity is provided. The method can include the steps of forming a cavity in a core structure of a core layer, laminating each of a top surface and a bottom surface of the core structure with an adhesive layer and a metal layer to prepare a laminate structure and cover the cavity to define a closed cavity. The method also includes forming vias through the laminate structure, and patterning the metal layers in the laminate structure.

A circuit board with reduced dielectric losses enabling the movement of high frequency signals includes an inner circuit board and two outer circuit boards. The inner circuit board includes a first conductor layer and a first substrate layer. The first conductor layer includes a signal line and two ground lines on both sides of the signal line. The first substrate layer covers a side of the first conductor layer and defines first through holes which expose the signal line. Each outer circuit board includes a second substrate layer and a second conductor layer. The second substrate layer abuts the inner circuit board and defines second through holes which are not aligned with the first through holes, partially surrounding the signal line with air which has a very low dielectric constant. A method for manufacturing the high-frequency circuit board is also disclosed.

A component carrier includes a core having a recess, an electronic component arranged in the recess, a laminated electrically insulating sheet covering at least part of the core and of the electronic component and filling a gap between a lateral surface of the electronic component and a lateral surface of the core in the recess, and a further electrically insulating layer structure laminated on top of the sheet.

A printed wiring board includes: an inner insulating layer including a conductive wire; a first outermost insulating layer disposed on a first surface of the inner insulating layer; and a second outermost insulating layer disposed on a second surface of the inner insulating layer. A bending elastic modulus of each of the first outermost insulating layer and the second outermost insulating layer ranges from ¼ to ¾, inclusive, of a bending elastic modulus of the inner insulating layer. A glass transition temperature of each of the first outermost insulating layer and the second outermost insulating layer falls within ±20° C. of a glass transition temperature of the inner insulating layer.

A carbene-coated metal foil is produced by applying an N-heterocyclic carbene (NHC) compound to one or more surfaces of a metal foil (e.g., an electrodeposited copper foil having a surface that is smooth and non-oxidized). The NHC compound contains a matrix-reactive pendant group that includes at least one of a vinyl-, allyl-, acrylic-, methacrylic-, styrenic-, amine-, amide- and epoxy-containing moiety capable of reacting with a base polymer (e.g., a vinyl-containing resin such as a polyphenylene oxide/triallyl-isocyanurate (PPO/TAIC) composition). The NHC compound may be synthesized by, for example, reacting a halogenated imidazolium salt (e.g., 1,3-bis(4-bromo-2,6-dimethylphenyl)-4,5-dihydro-1H-imidazol-3-ium chloride) and an organostannane having a vinyl-containing moiety (e.g., tributyl(vinyl)stannane) in the presence of a palladium catalyst. In some embodiments, an enhanced substrate for a printed circuit board (PCB) is produced by laminating the carbene-coated metal foil to a substrate that includes glass fiber impregnated with the base polymer.

Ultra-thin dielectric printed circuit boards (PCBs) are provided. An ultra-thin dielectric layer may be coupled to a first conductive layer on a first side of the ultra-thin dielectric layer. A second conductive layer may be coupled to a second side of the ultra-thin dielectric layer, and the ultra-thin dielectric layer is thinner than at least one of the first conductive layer and the second conductive layer. The second conductive layer may be patterned to form electrical paths. The patterned second conductive layer may be filled with a dielectric filler. One or more conductive layers and one or more ultra-thin dielectric layers may also be coupled to the second conductive layer.

A resin multilayer substrate includes a multilayer body including resin layers and adhesive layers that are laminated, via conductors in the resin layers, and bonding portions in the adhesive layers. The bonding portion is connected to the via conductor. One of the resin layer and the adhesive layer is a gas high-permeable layer having a higher gas permeability than the other one. The bonding portion includes an organic substance, or has a higher void content rate per unit plane sectional area than the via conductor. At least a portion of each of the bonding portions contacts the gas high-permeable layers.

A flexible laminated sheet manufacturing method includes thermocompression-bonding an insulation film formed of a liquid crystal polymer onto a metal foil between endless belts to form a flexible laminated sheet. The thermocompression bonding includes heating the flexible laminated sheet so that the maximum temperature of the sheet is in the range from a temperature that is 45° C. lower than the melting point of the liquid crystal polymer to a temperature that is 5° C. lower than the melting point. The thermocompression bonding also includes slowly cooling the flexible laminated sheet so that an exit temperature, which is a temperature of the sheet when transferred out of the endless belts, is in the range from a temperature that is 235° C. lower than the melting point of the liquid crystal polymer to a temperature that is 100° C. lower than the melting point.