With the rapid development of microelectronics technology, surface mount components is becoming smaller, lightweight and multi-purpose integrated circuits as small outline (SOIC), its lead distribution on both sides of the device, lead pitch 1.27 mm, Quad Flat plastic IC (QFP), lead distribution of the four sides of the device, lead center distance 1-0.8-0.65 mm, plastic leaded chip carrier (PLCC), lead was "J" type, lead pitch of 1.27 mm leadless ceramic chip carrier (LCCC), is to spread the metal edges of the device pads instead of wire and metal distribution of ball grid array pad on the bottom of the chip (BGA) and so on. Therefore, the surface of the device miniaturization requirements, prompted the design of printed circuit boards and printed circuit board manufacturing technology has become more high-density, high reliability and multi-level direction. Research and development of multi-layer printed circuit board manufacturing technology, so that means more printed circuit board manufacturing high precision and sharp electronic technology can only meet the needs of the development.

multi-layer printed circuit board on the development and production process, the frequent occurrence of certain product quality issues, particularly the inner layer of multi-layer printed circuit board, with the electronic assembly to a higher density development, increasing wiring density, a lot of inner and outer conductor width and spacing of only 0.10-0.075 mm hole and buried them porous holes, blind holes and so on. Such as Ball Grid Array - kind of assembly structure. Assembly structure according to the requirements in the design of printed circuit boards and manufacturing wiring must meet its density of 0.10-0.125 mm outer and inner layer is 0.10-0.075 mm, pore size of 0.25-0.35 mm and other design requirements and is six boards. This requires the layer to be very accurate alignment. However, due to workmanship errors, multi-layer printed circuit board inner short circuit occur. While the inner short is the biggest multi-layer printed circuit board quality issues, this is because the inner multi-layer printed circuit board if there is short defects, it becomes difficult to repair the product. If Denso found such defects, will cause great economic losses. Therefore, to solve the multi-layer printed circuit board inner path problem, we must first figure out the inner circuit of the main production process factors, the process can be targeted to the appropriate countermeasures.