Advantages and differences of three kinds of vias in PCB 2021-10-27

pcb There are three types of vias in ： Through hole 、 Blind hole and buried hole .

• Through hole ： It belongs to a kind of common through hole , The through hole passes through the whole circuit board , It can be used to realize internal interconnection or as the installation positioning hole of components . Through holes are easy to identify , Just put PCB Hold it up to the light , You can see that a bright hole is a through hole .
• Blind hole ： take PCB The outermost layer of the circuit is connected with the adjacent inner layer by electroplating holes , Because you can't see the other side , So it is called blind pass . It is located in PCB The top and bottom surfaces of the slab , Having a certain depth , It is used to connect the surface circuit and the inner circuit below , The depth of the hole usually does not exceed a certain ratio ( Aperture ).
• Bury the hole ： Is located in PCB Any internal circuit layer is connected but not connected to the outer layer . This process cannot be achieved by drilling holes after bonding , It is necessary to drill holes in individual circuit layers , First, the inner layer is partially bonded, and then electroplating is required Handle , Finally, it can be fully bonded , It takes more time than the original through hole and blind hole , So the price is also the most expensive . This process is usually used only for high density (HDI) Circuit board , To increase the availability of other circuit layers Space .

Both blind holes and buried holes are located in the inner layer of the circuit board , Before lamination, the through-hole forming process is used to complete , Several inner layers may be overlapped during via formation .

bury 、 blind 、 Through hole bonding technology is also an important way to improve the high density of printed circuit . General burying 、 Blind holes are tiny holes , In addition to increasing the number of wiring on the board , bury 、 Blind holes are made of “ lately ” Interconnection between inner layers , Greatly reduce the number of through holes formed , The setting of isolation panel will also be greatly reduced , Thus, the number of effective wiring in the board and interconnection between layers are increased , The high density of interconnection is improved .

So bury 、 blind 、 The multi-layer plate with through-hole combination is better than the conventional full through-hole plate structure , Under the same size and number of layers , The interconnection density is increased by at least 3 times , If under the same technical indicators , bury 、 blind 、 Printed board with through hole combination , Its size will be greatly reduced or the number of layers will be significantly reduced .
Under the same size and number of layers , One with buried 、 blind 、 The interconnection density of the through-hole bonded multilayer board is at least as high as that of the conventional all through-hole board 3 times . That is to say, under the same technical indicators , bury 、 blind 、 Circuit board with through hole combination , It will greatly reduce the size of the board or reduce the number of layers of the board .

Therefore, in high-density surface mount printed boards , bury 、 Blind hole technology has been applied more and more , Not only in mainframe computers 、 Surface mounted printed boards in communication equipment, etc , And in civilian use 、 It has also been widely used in industrial fields , It has even been used in some thin plates , Like all kinds of PCMCIA、Smard、IC Thin plate with more than six layers, blind embedded hole with multiple layers, etc PCB Line processing .

So bury 、 Blind hole technology has been used more and more in high-density surface mount printed boards . More Than This , On mainframe computers 、 Surface mounted printed boards and civil products in communication equipment, etc 、 It has been widely used in industrial fields . It has also been applied in some thin plates , Like all kinds of PCMCIA、Smard、IC Thin blind buried holes with more than six layers of cards, etc PCB Circuit board processing .

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