International Business Machines Corporation

Paula M Nixa

Joseph Paul Kuczynski

Bruce John Chamberlin

A method for fabricating an asymmetric printed circuit board with minimized warpage. The method includes determining a first resin area and a second resin area in a stack of printed circuit board layers. The method further includes performing computer modeling to predict a warpage of the printed circuit board layers during a predicted use of the printed circuit board layers. The method further includes determining a first target coefficient of thermal expansion for the first resin area and a second target coefficient of thermal expansion for the second resin area based on the computer modeling. The method further includes differentially curing resin in the first resin area and the second resin area based on the first target coefficient of thermal expansion and the second target coefficient of thermal expansion. The method further includes forming an asymmetric printed circuit board from the stack of printed circuit board layers.

Fabricating an asymmetric printed circuit board with minimized warpage

A printed circuit board and method of manufacturing same, the printed circuit board comprising a stack of layers. The stack of layers being comprised of alternating circuit layers and insulating layers that are laminated together. The stack of layers includes an area with resin cured to a degree. The area has a coefficient of thermal expansion that is dependent, at least in part, on the degree of curing of the resin.

Minimizing printed circuit board warpage

An enhanced substrate for use in printed circuit boards (PCBs) includes low-Dk-core glass fibers having low dielectric constant (Dk) cores. In some embodiments, the low-Dk-core glass fibers are filled with a low Dk fluid, such as a gas (e.g., air, nitrogen and/or a noble gas) or a liquid. After via holes are drilled or otherwise formed in the substrate, silane is applied to the ends of hollow glass fibers exposed in the via holes to seal the low Dk fluid within the cores of the hollow glass fibers. In some embodiments, the low-Dk-core glass fibers are filled with a solid (e.g., a low Dk resin). For example, a hollow glass fiber may be provided, and then filled with a low Dk resin in a liquid state. The low Dk resin within the hollow glass fiber is then cured to a solid state.

Substrate containing low-Dk-core glass fibers having low dielectric constant (Dk) cores for use in printed circuit boards (PCBs), and method of making same

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Rochester, MN, United States of America

Paula M Nixa