Browse Prior Art Database

Original Publication Date: 2002-Jan-01
Included in the Prior Art Database: 2003-Jun-18

Publishing Venue



The printed circuit board has been evoluting rapidly in the sights of the circuitry density, and the structure has changed from with the mechanical drilled through holes to with the micro photo vias, and the line pitch on the board comes to below 50um. Tough the leading edge line formation processes, optical pattern exposing, developping, Cu plating, Cu etching, etc. are keeping up the design rule with the density, they are sometimes resulting the electrical shortage with the incomplete Cu etching between the lines due to the fine dusts in the processes. Since a total printed circuit board comes defectice parts with a short part, the short repair process is mandatory required to salvage the board. In the industry, several tools, for example, micro end miller, fine exacto knife, etc. are available for the normal density printed circuit board and they work well to remove the remaining Cu between the lines, but they could not be applied to the high density lines with 50um pitch. This invention was done to prepare the repair process for the 50um pitch lines. Fig.1 is the outline view of this tool. It is made of the solid ziruconium ceramic and it furnishes a blade "A" on its bottom with the blade width matched with the line space. The blade hight is less than the insulator thickness under the Cu line not to cause damage to the underlayer conductors. And this tool has the preceding limb "B" on the both side of the blade not to cut in the board excessively in the depth. The operator holds this tool manually under the microscope, locates the blade into the line space, moves it forward to the short part with a slight force. This tool can works out well for the high density printed circuit board. 1 2 3