Patent ID: 6943439
Filing Date: 2005-09-13
Classification: H01L,H05K

Abstract:
1. A substrate, comprising: a core layer, at least a surface of the core layer being defined with a trace forming area; a plurality of conductive elements formed on the trace forming area of the core layer, each of the conductive elements having a first end portion and a second end portion opposed to the first end portion, allowing the first end portion to be urged with external electrical connection so as to plate a metal layer on the second end portion; at least a check point formed on the surface of the core layer outside the trace forming area, the check point being spaced apart from the conductive elements and free of external electrical connection, wherein the check point is adapted to change color for determining cleanness of the substrate after a plasma cleaning step is performed on the substrate, and the check point is located at a position between the trace forming area and an edge of the substrate; and at least a solder mask layer applied over the surface of the core layer formed with the conductive elements and the check point, allowing the second end portions of the conductive elements and the check point to be exposed to outside of the solder mask layer.