Systematic classification of circuit boards for the following three
We have just mentioned, on the most basic PCB, components concentrated in the side, wire centres on the other side. Because wires only occurs on one side, so we'll call this PCB is called single-sided boards (Single-sided). Because a single panel in the design line there are many severe restrictions on (because only one side, wiring can't * and have to go around the path alone), so only the earlier circuit using such boards.
Both sides of the circuit board and wiring. But with both sides of the wire must have appropriate electrical connection lines in between the two sides. This "bridge" is called a pilot hole (via). Pilot hole is on the PCB, or coated metal-filled holes, it can work with both sides of the wire is connected. Because the double-sided Board area than a single large Panel 1 time, and because of wiring can be interlaced (went around to the other side), it is more suitable for use in single panel
More complex circuits.
"MLB" in a more complex application requirements, the circuit can be arranged together into multi-layer structure and pressure, between layers and each layer is built through-hole circuit connected circuits.
Inner layer lines
CCL cut into sizes suitable for processing. Substrate laminator usually need to brush before grinding, micro-etching method the Board do the right rough copper processing, then the appropriate temperature and pressure dry film photoresist seal attached to it. Will post good substrate into the UV exposure of dry film photo-resist exposure, photoresist film light polymerization after ultraviolet irradiation (film in the region at a later development, copper etching steps will be preserved as Etching Resist), and transferring negative lines on the image on the surface dry film photoresist. After the tear film on the surface of protective film, sodium carbonate aqueous solution on the membrane surface areas that are not affected by light treatment removal, and bare with hydrochloric acid and hydrogen peroxide mixed solution of copper corrosion removal, forming lines. Then with aqueous sodium hydroxide to make a graceful exit of dry film photo-resists wash. For six (inclusive) above the inner layer circuit board to automatically locate the punch out of story lines on the base of riveting hole.