Application of full-phase microscope in PC board production
The role of raw material inspection As the copper-clad laminate required for multi-layer PCB production, its quality will directly affect the production of multi-layer PCB. The following important information can be obtained from the slices taken by metallographic microscope:
1.1 Copper foil thickness, check whether the copper foil thickness meets the production requirements of multilayer printed boards.
1.2 The thickness of the insulating dielectric layer and the arrangement of the prepreg.
1.3 In the insulating medium, the warp and weft arrangement of glass fibers and the resin content.
1.4 Defect information of metallographic microscope laminates The defects of laminates mainly include the following types:
(1) Pinhole refers to a small hole that completely penetrates a layer of metal. For multilayer printed boards with higher wiring density, such defects are often not allowed.
(2) Pockmarks and pits Pimples refer to small holes that do not completely penetrate the metal foil: pits refer to local point-like protrusions on the pressed steel plate that may be used during the pressing process, resulting in the appearance of cracks on the copper foil surface after pressing. Moderate subsidence. It can be determined whether the existence of the defect is allowed by measuring the size of the small hole and the depth of the sag through the metallographic section.
(3) Scratches Scratches refer to thin and shallow grooves drawn on the surface of copper foil by sharp objects. The width and depth of scratches are measured by metallographic microscope sections to determine whether the existence of the defect is allowed.
(4) Wrinkles Wrinkles refer to the creases or wrinkles of the copper foil on the surface of the platen. The existence of this defect visible through metallographic section is not allowed.
(5) Lamination voids, white spots and blisters Lamination voids refer to the areas where there should be resin and adhesive inside the laminate, but the filling is incomplete and there are missing areas; white spots occur inside the base material, where the fabric interweaves The phenomenon of separation of glass fiber and resin, manifested as scattered white spots or "cross lines" under the surface of the substrate; blistering refers to the local expansion between the layers of the substrate or between the substrate and the conductive copper foil, resulting in local separation The phenomenon. The existence of such defects depends on the specific circumstances to decide whether to allow it.
