The role of metallographic microscope in process control of PCB board slicing technology
1. Role in raw material incoming inspection As a copper-clad laminate required for the production of multi-layer PCB boards, its quality will directly affect the production of multi-layer PCB boards. The following important information can be obtained from the sections taken by metallography:
1.1 Copper foil thickness, check whether the copper foil thickness meets the production requirements of multi-layer printed boards.
1.2 The thickness of the insulating dielectric layer and the arrangement of the prepreg sheets.
1.3 The warp and weft arrangement of glass fibers and the resin content in the insulating medium of Olympus metallographic microscope.
(1) Pinhole
Refers to a small hole that completely penetrates a layer of metal. For the production of multi-layer printed boards with higher wiring density, this kind of defect is often not allowed to occur.
(2)Pockmarks and dents
Pit points refer to small holes that do not completely penetrate the metal foil; dents refer to local dot-like protrusions on the pressed steel plate used during the pressing process, causing gentle subsidence on the surface of the pressed copper foil. The size of the hole and the depth of the subsidence can be measured through metallographic sections to determine whether the existence of the defect is allowed.
(3)Scratches
Scratches refer to thin and shallow grooves scratched on the surface of copper foil by sharp objects. Measure the scratch width and depth through metallographic microscope sections to determine whether the existence of the defect is allowed.
(4) Wrinkles
Wrinkles refer to the creases or wrinkles in the copper foil on the surface of the pressure plate. The existence of this defect can be seen through metallographic sectioning and is not allowed.
(5) Lamination voids, white spots and blisters
Laminated voids refer to areas where there should be resin and adhesive inside the laminate, but are incompletely filled and missing; white spots occur inside the base material, where the glass fiber and resin are separated at the intersection of the fabric, which is manifested as Scattered white spots or "cross patterns" appear under the surface of the substrate; blistering refers to the phenomenon of local expansion and local separation between the layers of the substrate or between the substrate and the conductive copper foil. The existence of such defects will be determined depending on the specific circumstances.
