Issue link: https://iconnect007.uberflip.com/i/1453746
108 PCB007 MAGAZINE I FEBRUARY 2022 able solder mask coatings to precision ink jet printing. e system I found most interesting was identified as an automated optical shap- ing (AOS) system. is AOS system is unique because it not only locates and identifies the defects in the etched circuit pattern, it has the ability to automatically correct the defects. As it was explained to me, the key to this pro- cess is the company's image acquisition tech- nology where it captures precise images of the defect area, analyzes and compares the defect shape to CAM data used to initially develop the circuit pattern image, and defines where excess copper requires ablation as well as pinpoint the location of interrupted portions of copper con- ductors that need to be reformed. Eliminating excess copper, for example, shorts, protrusions, copper splashes, and exces- sively-sized features, is accomplished using built- in laser ablation technology. e laser reshap- ing process eliminates the unwanted excess cop- per, reforming the circuit features to the original profile defined in the CAM file. An example of a copper bridge defect and the result of laser cir- cuit reshaping is compared in Figure 1. Regarding copper removal, the laser process can provide reshaping down to 25 µm for both copper conductor features and the spacing separating features. As far as copper ablation speed, the manufacturer estimates that the sys- Companies have found that human inspec- tion of the individual circuit layers consumes a significant amount of time, and even with magnification, may not identify all defects on the panel surfaces. When fabricating complex, multi-layer circuit boards, automating image verification on all circuit layers before lami- nation has proven indispensable. ese AOI systems are programmed to identify circuit path irregularities: opens, shorts, or anoma- lies within the circuit paths that are outside the user-defined tolerance limits. I had the pleasure of interviewing Chad Smith, the AOI expert representing Orbotech West. e 35-year-old company is well known for a broad range of products—including auto- mated inspection, direct imaging for defin- ing the PCB circuit pattern, and photoimage- Figure 1: 3D laser ablation enables precise reshaping and elimination of excessive solder. Companies have found that human inspection of the individual circuit layers consumes a signifi- cant amount of time...