Lamination
Some PCBs have trace layers inside the PCB and are called multi-layer PCBs. These are formed by bonding together separately etched thin boards.
Drilling
Holes, or vias, through a PCB are typically drilled with tiny drill bits made of solid tungsten carbide. The drilling is performed by automated drilling machines with placement controlled by a drill tape or drill file. These computer-generated files are also called numerically controlled drill (NCD) files or "Excellon files". The drill file describes the location and size of each drilled hole.
When very small vias are required, drilling with mechanical bits is costly because of high rates of wear and breakage. In this case, the vias may be evaporated by lasers. Laser-drilled vias typically have an inferior surface finish inside the hole. These holes are called micro vias.
It is also possible with controlled-depth drilling, laser drilling, or by pre-drilling the individual sheets of the PCB before lamination, to produce holes that connect only some of the copper layers, rather than passing through the entire board. These holes are called blind vias when they connect an internal copper layer to an outer layer, or buried vias when they connect two or more internal copper layers and no outer layers.
The walls of the holes, for boards with 2 or more layers, are plated with copper to form plated-through holes that electrically connect the conducting layers of the PCB. For multilayer boards, those with 4 layers or more, drilling typically produces a smear comprised of the bonding agent in the laminate system. Before the holes can be plated through, this smear must be removed by a chemical de-smear process, or by plasma-etch.
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[edit] Exposed conductor plating and coating
The places to which components will be mounted are typically plated, because bare copper oxidizes quickly, and therefore is not readily solderable. Traditionally, any exposed copper was plated with solder by hot air solder levelling (HASL). This solder was a tin-lead alloy, however new solder compounds are now used to achieve compliance with the RoHS directive in the EU, which restricts the use of lead. Other platings used are OSP (organic surface protectant), immersion silver (IAg), immersion tin, electroless nickel with immersion gold coating (ENIG), and direct gold. Edge connectors, placed along one edge of some boards, are often gold plated.
Electrochemical migration (ECM) is the growth of conductive metal filaments on or in a printed circuit board (PCB) under the influence of a DC voltage bias.[1][2]
[edit] Solder resist
Areas that should not be soldered to may be covered with a polymer solder resist (solder mask) coating. The solder resist prevents solder from bridging between conductors and thereby creating short circuits. Solder resist also provides some protection from the environment.
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[edit] Screen printing
Line art and text may be printed onto the outer surfaces of a PCB by screen printing. When space permits, the screen print text can indicate component designators[1], switch setting requirements, test points, and other features helpful in assembling, testing, and servicing the circuit board.
Screen print is also known as the silk screen, or, in one sided PCBs, the red print.
Lately some digital printing solutions have been developed to substitute the traditional screen printing process. This technology allows printing variable data onto the PCB, including serialization and barcode information for traceability purposes.
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[edit] Test
Unpopulated boards may be subjected to a bare-board test where each circuit connection (as defined in a netlist) is verified as correct on the finished board. For high-volume production, a Bed of nails tester, a fixture or a Rigid needle adapter is used to make contact with copper lands or holes on one or both sides of the board to facilitate testing. A computer will instruct the electrical test unit to send a small amount of current through each contact point on the bed-of-nails as required, and verify that such current can be seen on the other appropriate contact points. A "short" on a board would be a solid connection where there should be no connection. An "open" is between two points that should be connected and are not. For small- or medium-volume boards, flying-probe and flying-grid testers use moving test heads to make contact with the copper/silver/gold/solder lands or holes to verify the electrical connectivity of the board under test

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[/i][/B][/SIZE][/COLOR]纹理
　　有些电路板PCB里有微量层,叫做多层PCB组件。这些是由连接在一起蚀刻薄木板分别。
　　钻探
　　孔或焊,通过印刷电路板通常采用小钻头的硬质合金。该机由自动打孔机和位置控制或磁带演练演练文件。这些计算机生成的文件也被称为“数控钻(非圆轮链传动)文件或“Excellon文件”。这个钻头的位置和大小的文件描述每个钻孔。
　　当很小,钻要求焊机械位是昂贵的,因为高水平的磨损和破损。在这种情况下,可以通过激光焊蒸发掉了。通常有一个低Laser-drilled焊孔内表面光洁度。这些漏洞被称为微焊。
　　它也可能与controlled-depth钻井、激光打孔,或由pre-drilling个体的纹理,在生产孔相连的只有部分的铜层,而不是通过整个董事会。这些洞时被称为盲焊连接到一个内部铜层,要么埋葬外层焊连接两个或更多时,没有内部铜层外层。
　　墙上的洞,为板和2个或更多的层次,是镀铜形成plated-through孔,电连接进行层电路板。对于多层木板,那些有四层或更久,钻孔通常产生涂片组成的粘结剂的系统中。之前的小洞可以通过这个污迹,包裹必须清除了化工de-smear过程,或由plasma-etch。
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　　[编辑]暴露的导体电镀和涂料
　　在组件将会安装通常镀铜,因为生氧化快,因此不容易电镀面很大。传统上,任何接触焊铜镀锡热空气即(HASL)。这是一个铅锡焊料合金,但现在使用新化合物来达到符合RoHS要求的产品,在欧盟的限制使用铅。使用其他platings OSP(有机表面保护剂)、浸银(IAg)、浸锡、镍和浸金涂料(ENIG)和直接的黄金。边连接器,安放在沿边缘有些板,通常是金子被镀的。
　　移民(ECM)电化学导电金属丝的增长上或在印刷电路板(PCB)的影响下,一个直流电压偏置。[1][2]
　　[编辑]锡抵抗
　　区域,不应该被焊接到可以覆盖着一层焊抵抗(焊接罩聚合物涂料。锡焊料从抵抗防止导体间,从而营造桥短路。焊锡抗拒也提供一些保护环境。
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　　[编辑]丝网印刷
　　线条和文本可以打印到外表面的由丝网印刷电路板。当空间允许,丝网印刷文字可以显示组件designators[1],开关设定的要求,测试点,以及其他特点对装配、测试及维修的电路板。
　　屏幕打印也被称为丝网,甚至在十有八九,红色的印刷电路板。
　　最近一些数码印刷解决方案,已经发展成为替代传统的丝网印刷工艺。这个技术允许打印变量的数据到PCB板,包括串行化和条码信息追溯用途。
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　　编辑]测试[m].北京:
　　也许受无人在每一个bare-board测试电路连接(定义在一个netlist)是正确的完成验证。为大批量生产、钉床上,或一个测试用针适配器刚性接触铜土地或孔一边或两边的板,便于检测。计算机将指导电气测试单位送少量的电流通过每个接触点的要求,把带有这种探针检验这种电流可以出现在其他适当的接触点。“在一个董事会将是一个坚实的连接那里应该是没有联系。一个名为“开放”是两点之间的连接,这应该是没有意义的。对于小-或medium-volume板,flying-probe和flying-grid测试员使用移动测试前往与铜/银金/焊锡土地或孔核实电气连接板的测试

全是英文，想表达什么……