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A via (Latin, 'path' or 'way') is an electrical connection between two or more metal layers of a printed circuit boards (PCB) or integrated circuit. Essentially a via is a small drilled hole that goes through two or more adjacent layers; the hole is plated with metal (often copper) that forms an electrical connection through the insulating layers.
A coupon or test coupon is a printed circuit board (PCB) used to test the quality of a printed wiring board (PWB) fabrication process. Test coupons are fabricated on the same panel as the PWBs, typically at the edges. Coupons are then inspected to ensure proper layer alignment, electrical connectivity, and cross sectioned to inspect internal ...
The ANOVA results showed that the strain concentration factor was the most important variable, followed with the ductility factor, metallization thickness, and via wall angle. Prabhu et al. [ 10 ] conducted a finite element analysis (FEA) on an HDI microvia structure to determine the effect of accelerated temperature cycling and thermal shock.
A 4-layer HDI microvia PCB is equivalent in quality to an 8-layer through-hole PCB, so HDI technology can reduce costs. HDI PCBs are often made using build-up film such as ajinomoto build-up film, which is also used in the production of flip chip packages. [15] [16] Some PCBs have optical waveguides, similar to optical fibers built on the PCB. [17]
Through-hole (leaded) resistors. In electronics, through-hole technology (also spelled "thru-hole") is a manufacturing scheme in which leads on the components are inserted through holes drilled in printed circuit boards (PCB) and soldered to pads on the opposite side, either by manual assembly (hand placement) or by the use of automated insertion mount machines.
Dry film conformal coating thickness measurement. An alternative to wet film measurement is by using eddy currents. The system works by placing the test head on the surface of the conformal coating. When liquid water is present, a pinhole can form in the coating. This is considered a defect and can be eliminated with appropriate steps and training.
In electronic engineering, a through-silicon via (TSV) or through-chip via is a vertical electrical connection that passes completely through a silicon wafer or die. TSVs are high-performance interconnect techniques used as an alternative to wire-bond and flip chips to create 3D packages and 3D integrated circuits.
Structural integrity may be compromised, e.g., by misalignment during drilling, so that too much copper may be removed by the drill hole in the area where a trace connects to the pad or via. [ 2 ] [ 3 ] [ 5 ] An extra advantage is the enlarging of manufacturing tolerances, making manufacturing easier and cheaper.