Electronics manufacturing services providers who use conventional printed circuit board assembly and manufacturing models are scrambling to augment their production facilities to handle increasingly smaller boards like those used for IoT devices.
At today’s advanced printed circuit board (PCB) houses, savvy leaders are homing in on newer technologies and merging conventional surface-mount technology manufacturing with the newer microelectronics manufacturing. Why? Because sophisticated IoT PCBs demand a different breed of inspection and calibration to comply with extremely miniature dimensions and that’s where PCB microelectronics lives.
Take for example, the newer higher-powered laser microscopes introduced on the microelectronics assembly and manufacturing floor. These tools are tailored to perform inspection and calibration tasks that legacy PCB manufacturing systems cannot handle because they cannot deal with the minutest details imaginable. Those minute details are the cornerstone of microelectronics manufacturing.
Capabilities of advanced laser microscopes
Tools such as the laser microscopes, perform die or chip, epoxy resin and solder mask bleeding and air bridge inspections. They also calculate Z-axis dimensions and create 3D rendering. Why are these manufacturing tasks so important? All fall under the umbrella of assuring IoT device reliability and operational integrity. These highly advanced laser microscopes check for die surface defects, such as extremely fine cracks or miniscule chipping at the corners of a die. These scopes also quickly spot corrosion, contamination or oxidation.
It’s important to prevent floating die. In cases like this, miscalculating the amount of epoxy under the die for the die attach process results in epoxy resin bleeding. In other words, a die isn’t completely attached to the substrate. The microscopes verify that a poorly produced die attach doesn’t go any further in the IoT PCB manufacturing process.
Microscopes perform inspection for solder mask bleeding. This means the mask may bleed onto the pad where wire bonding is installed. The pad’s size may not be sufficient to perform the bonding. Again, these high-powered scopes inspect and verify this issue doesn’t exist.
The microscopes also inspect air bridges. An air bridge is the air distance created to bypass a component located between two other components. It connects a wire bond from one point to another and passes over the middle component.
Aside from inspections, microscopes calculate length, width and height in the Z-axis for dealing with height restrictions. Sometimes dies are attached in gold surface finish cavities, and they need to be precisely height controlled. This permits a perfect fit in those cavities before attaching wires via wire bonding after die attach. The high-powered scopes are perfect tools to view cavity length and depth and to perform height measurements in the Z-axis.
Finally, 3D rendering of the wire bond pads, substrate height or paste height provide microelectronics manufacturing technicians a clear visual. Technicians can calculate the length of the wire bonds, their loop curvatures and underfill thickness for the proper die attach and accurate wire bonding.
When it comes to IoT PCB microelectronics manufacturing, there should not be any question about the tools needed to achieve accurate inspections and calibrations.
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