| 摘要 |
PURPOSE: A printed circuit board is provided to prevent the accumulation of an electric charge by forming a flat plate for grounding on a lower surface of the printed circuit board. CONSTITUTION: A semiconductor chip mounting region is formed so that a semiconductor chip is mounted on an upper surface of a resin substrate(1). A conductive trace are arranged on all directions of the mounting region. A solder mask is coated on an upper portion of the resin substrate(1) in order to protect the conductive trace. A through-hole(5) connects the conductive trace and upper and lower portions of the resin substrate(1). A solder ball land(6) is connected to the lower portion of the resin substrate(1) by the through-hole(5) to form a region where a solder ball is welded. A solder mask(4b) is coated on the lower portion of the resin substrate(1) except the solder ball land(6). A gold gate(7) is connected to a ground signal of the conductive trace and provided with an encapsulation material for protecting the semiconductor chip. A ground grounding flat plat(8) is connected to the ground signal of the conductive trace.
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