... between layers is necessary due to increased densities and reduced dependence on through-hole technology. Area-array packages such as BGAs, CSPs, and flip chips shift | PCB | the burden of interconnect fan-out to the PCB, increasing the need for higher wiring capacity. As the form factor for such devices continues to shrink | PCB | and I/O density mushrooms, the size and density of HDI microvias must follow suit. In 1997, for instance, the number of microvias on a typical | PCB | PCB panel was about 20,000. Now, a typical HDI panel contains about 250,000 microvias.4 | THE COMBINATION | of high demand, abbreviated product cycles, shrinking | PCB | IC packaging, and soaring interconnect densities places a high value on the development of cost-effective, high-volume microvia formation processes. | HIGH-VOLUME MICROVIA | Formation Methods | PCB | There are four techniques most commonly used to generate microvias: mechanical drilling, laser drilling, plasma, and photo (liquid or film) formation. This article will ...
[ Pcb ]


... with each new job and should contain the following information to ensure that the finished board is to your requirements. - Always required even | PCB | when a drill file is supplied, to enable inspection of panels immediately after drilling and finished boards prior to despatching. Hole sizes must be clearly | PCB | represented with distinct differences between each size. Tolerances are not required unless different to our standard of +0.1 / -0.05 mm. - Preferred with overall | PCB | mechanical dimensions including notches, cutouts and slots. Also preferred is a positioning (datum) dimension (drilled hole is best). Tolerances are not required unless different to | PCB | our standard of + / -0.25 mm. Other information required for all boards includes: board thickness (standard = 1.6mm) base copper thickness (std = 18mm) | PCB | solder mask colour (std = green) solder mask type (std = liquid photoimageable) component legend colour (std = white) bare board testing requirement (std for | PCB | multilayer and fine line production ...
[ Pcb ]


... using Gerber data, switch to 274X. 274D is obsolete; the external aperture information is more cumbersome and difficult for fabricators to deal with because | PCB | they have to worry about translators and parsers to read the aperture table information. As a result, aperture data might be misinterpreted. Worse, someone might | PCB | have typed in the information manually - and erroneously. By contrast, in 274X, all the aperture information is contained within the Gerber file, which can | PCB | be read by most CAM tools automatically. For netlists, IPC-D-356 is the preferred format for fabrication. It's widely used by many of the bare-board test-fixturing | PCB | machines and is one of the only true ways to identify power- to-ground shorts. With the information in this format coming directly from the engineering | PCB | CAD system, there's no danger of the fabricator "reverse engineering" the netlist from the Gerber files. Next up are the internal plane layers. For some | PCB | reason, CAD engineers like them to be ...
[ Pcb ]