For high -tech development, people need high performance, small volume, and many functions, which prompts the manufacturing of the line board to manufacture to light, thin, short, small development, limited space, and more functions. The wiring density becomes larger. Small. From 1995 to 2007, the minimum pores of mechanical drilling batch capacity fell from 0.4mm to 0.2mm or even smaller. Metal -tonged pores are getting smaller and smaller. The metallic holes depended on the inter -layer interconnection are directly related to the reliability of the printing board. With the narrowing of the aperture, there are no miscellaneous objects that have no effect on the large pores, such as grinding brushing debris and volcanic ash. Once they remain in small holes, chemical sinking copper and electroplating copper will lose their effects. Metal -oriented fatal killer.

　　The design of the printed circuit board is based on the circuit schematic diagram to realize the function required by the circuit designer. The design of the printing circuit board mainly refers to the design of the layout. It is necessary to consider the layout of the external connection, the optimization layout of the internal electronic component, the optimization layout of the metal connection and the pores, the electromagnetic protection, thermal dissipation, and other factors. Excellent layout design can save production costs and achieve good circuit performance and heat dissipation performance. The simple layout design can be implemented by hand. The complex layout design needs to be achieved with a computer -aided design (CAD).