... Microvias have become an attractive interconnect alternative when the wiring density on a PCB approaches 160 I/Os per sq. in.2 Viewed another way, a | MULTILAYER CIRCUITS MAKER | typical PCB in 1997 averaged about 485 I/Os per sq. in., whereas this year the lead density should average close to 1,800 leads/sq. in. for | MULTILAYER CIRCUITS MAKER | multilayer PCBs.3,4 Space-efficient routing between layers is necessary due to increased densities and reduced dependence on through-hole technology. Area-array packages such as BGAs, CSPs, and | MULTILAYER CIRCUITS MAKER | flip chips shift the burden of interconnect fan-out to the PCB, increasing the need for higher wiring capacity. As the form factor for such devices | MULTILAYER CIRCUITS MAKER | continues to shrink and I/O density mushrooms, the size and density of HDI microvias must follow suit. In 1997, for instance, the number of microvias | MULTILAYER CIRCUITS MAKER | on a typical PCB panel was about 20,000. Now, a typical HDI panel contains about 250,000 microvias.4 | THE COMBINATION | of high demand, abbreviated | MULTILAYER CIRCUITS MAKER | product cycles, shrinking IC packaging, and soaring ...
[ Multilayer Circuits Maker ]


... although accepted in other formats. (Refer to CID-014 for information on Documentation in Digital Form). PHOTOPLOTS OR PHOTOPLOT files are the only acceptable form | MULTILAYER CIRCUITS MAKER | of supplying images for multilayers and boards with fine (0.2mm or smaller) tracks. DRAWINGS Drawings must be supplied with each new job and should contain | MULTILAYER CIRCUITS MAKER | the following information to ensure that the finished board is to your requirements. HOLE SIZES Always required even when a drill file is supplied, to | MULTILAYER CIRCUITS MAKER | enable inspection of panels immediately after drilling and finished boards prior to despatching. Hole sizes must be clearly represented with distinct differences between each size. | MULTILAYER CIRCUITS MAKER | Tolerances are not required unless different to our standard of +0.1 / -0.05 mm. MECHANICAL SIZES Preferred with overall mechanical dimensions including notches, cutouts and | MULTILAYER CIRCUITS MAKER | slots. Also preferred is a positioning (datum) dimension (drilled hole is best). Tolerances are not required unless different to our standard of + / -0.25 | MULTILAYER CIRCUITS MAKER | mm. ...
[ Multilayer Circuits Maker ]


... substrate with electroplating or with etching, or with both | SMOBC SOLDER MASK OVER BARE COPPER. | A method of fabricating a printed wiring | MULTILAYER CIRCUITS MAKER | board which results in the final metallization being copper with no other protective metal but the non soldered areas are coated by a solder resist, | MULTILAYER CIRCUITS MAKER | exposing only the component terminal areas. | SOLDER LEVELING |The process of dipping PCB's into hot liquids, or exposing them to liquid waves to achieve | MULTILAYER CIRCUITS MAKER | fusion. First, flux is applied to the board by dipping or brushing. Then the board is preheated in a liquid (maintained at 250 F). Next, | MULTILAYER CIRCUITS MAKER | the board is immersed in fusing liquid at 430 - 500 F. Finally, it is dipped in another 250 F liquid to cool it and | MULTILAYER CIRCUITS MAKER | reduce thermal shock. Thin fused coatings can be applied. | SOLDER RESISTS (SOLDERMASK) | Coatings which mask off and surface insulate those areas of a | MULTILAYER CIRCUITS MAKER | circuit where soldering is not desired. | STEP AND REPEAT | A method by which successive exposures of a single image are made to produce | MULTILAYER CIRCUITS MAKER | a ...
[ Multilayer Circuits Maker ]