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In electronic devices, printed circuit boards, or PCBs, are utilized to mechanically support electronic components which have their connection leads soldered onto copper pads in surface mount applications or through rilled holes in the board and copper pads for soldering the part leads in thru-hole applications. A board style may have all thru-hole components on the top or element side, a mix of thru-hole and surface install on the top just, a mix of thru-hole and surface mount parts on the top and surface area mount elements on the bottom or circuit side, or surface install elements on the leading and bottom sides of the board.

The boards are likewise utilized to electrically connect the needed leads for each component utilizing conductive copper traces. The element pads and connection traces are etched from copper sheets laminated onto a non-conductive substrate. Printed circuit boards are developed as single news agreed copper pads and traces on one side of the board only, double sided with copper pads and traces on the top and bottom sides of the board, or multilayer designs with copper pads and traces on top and bottom of board with a variable variety of internal copper layers with traces and connections.

Single or double sided boards consist of a core dielectric material, such as FR-4 epoxy fiberglass, with copper plating on one or both sides. This copper plating is etched away to form the real copper pads and connection traces on the board surfaces as part of the board manufacturing process. A multilayer board consists of a variety of layers of dielectric product that has actually been impregnated with adhesives, and these layers are used to separate the layers of copper plating. All of these layers are lined up and after that bonded into a single board structure under heat and pressure. Multilayer boards with 48 or more layers can be produced with today's technologies.

In a common four layer board style, the internal layers are often used to provide power and ground connections, such as a +5 V aircraft layer and a Ground aircraft layer as the 2 internal layers, with all other circuit and component connections made on the top and bottom layers of the board. Very complicated board designs might have a a great deal of layers to make the numerous connections for various voltage levels, ground connections, or for linking the numerous leads on ball grid variety gadgets and other big incorporated circuit package formats.

There are normally 2 kinds of product utilized to build a multilayer board. Pre-preg product is thin layers of fiberglass pre-impregnated with an adhesive, and is in sheet type, generally about.002 inches thick. Core product resembles an extremely thin double sided board in that it has a dielectric product, such as epoxy fiberglass, with a copper layer deposited on each side, typically.030 density dielectric product with 1 ounce copper layer on each side. In a multilayer board design, there are 2 techniques used to develop the wanted number of layers. The core stack-up method, which is an older technology, uses a center layer of pre-preg product with a layer of core material above and another layer of core product listed below. This combination of one pre-preg layer and 2 core layers would make a 4 layer board.

The film stack-up technique, a more recent innovation, would have core material as the center layer followed by layers of pre-preg and copper material built up above and listed below to form the final variety of layers needed by the board design, sort of like Dagwood building a sandwich. This approach enables the manufacturer flexibility in how the board layer densities are combined to fulfill the finished product density requirements by varying the number of sheets of pre-preg in each layer. When the product layers are finished, the whole stack is subjected to heat and pressure that triggers the adhesive in the pre-preg to bond the core and pre-preg layers together into a single entity.

The process of manufacturing printed circuit boards follows the actions listed below for most applications.

The process of identifying products, procedures, and requirements to satisfy the consumer's specifications for the board style based upon the Gerber file info offered with the purchase order.

The process of moving the Gerber file information for a layer onto an etch resist film that is put on the conductive copper layer.

The traditional procedure of exposing the copper and other areas unprotected by the etch resist movie to a chemical that gets rid of the vulnerable copper, leaving the safeguarded copper pads and traces in location; more recent processes use plasma/laser etching instead of chemicals to get rid of the copper product, enabling finer line meanings.

The procedure of lining up the conductive copper and insulating dielectric layers and pushing them under heat to activate the adhesive in the dielectric layers to form a strong board product.

The procedure of drilling all the holes for plated through applications; a second drilling procedure is utilized for holes that are not to be plated through. Information on hole location and size is consisted of in the drill drawing file.

The procedure of applying copper plating to the pads, traces, and drilled through holes that are to be plated through; boards are placed in an electrically charged bath of copper.

This is required when holes are to be drilled through a copper location but the hole is not to be plated through. Prevent this process if possible since it adds cost to the finished board.

The process of applying a protective masking material, a solder mask, over the bare copper traces or over the copper that has actually had a thin layer of solder used; the solder mask secures versus ecological damage, supplies insulation, protects versus solder shorts, and protects traces that run between pads.

The process of covering the pad locations with a thin layer of solder to prepare the board for the eventual wave soldering or reflow soldering process that will happen at a later date after the parts have actually been positioned.

The process of using the markings for element designations and part outlines to the board. Might be applied to just the top side or to both sides if elements are mounted on both top and bottom sides.

The process of separating several boards from a panel of identical boards; this process also allows cutting notches or slots into the board if needed.

A visual inspection of the boards; likewise can be the procedure of examining wall quality for plated through holes in multi-layer boards by cross-sectioning or other methods.

The procedure of looking for continuity or shorted connections on the boards by means applying a voltage in between various points on the board and determining if a present circulation takes place. Relying on the board complexity, this procedure might require a specially created test fixture and test program to incorporate with the electrical test system utilized by the board maker.