Patent ID: 7908965

Claim:
An underlay substrate that is arranged between a substrate sheet for manufacturing a printed circuit substrate and a suction stage when said substrate sheet is fixed on said suction stage by vacuum suction, wherein said substrate sheet is sectioned into first and second regions having an equal area, said first region includes a first printed circuit substrate formation region and a first blank region, said second region includes a second printed circuit substrate formation region and a second blank region, an area of said first blank region and an area of said second blank region are different from each other, said underlay substrate includes first and second blank corresponding regions that, when said underlay substrate is overlapped with said substrate sheet, face said first and second blank regions of said substrate sheet, respectively, one or plurality of first through holes are formed in said first blank corresponding region and one or plurality of second through holes are formed in said second blank corresponding region, and a sum of areas of said first through holes and a sum of areas of said second through holes are equal to each other.