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20 PCB007 MAGAZINE I OCTOBER 2023 a target pad and capture-annulus should look like aer laser drilling and post-treatment, and what copper grain structure yields which etch rate for optimizing the substrate differential etch and resolution limit. ese topics gener- ally fall into the category of individual factory know-how. In this article, we will present examples of applications where improved measurement and control of copper grain structure and topography provide significant gains in value to the PCB fab process. In the case of microvias, in addition to the traditional chemical analyses, white-light Feature Article by Alex Stepinski STEPINSKI GROUP e topic of intrinsic copper structure has been largely neglected in discussions regarding the PCB fabrication quality control process. At face value, this seems especially strange con- sidering that copper has been the primary con- ductor in all wiring boards and substrates since they were first invented. IPC and other stan- dards almost exclusively address copper thick- ness with some mild attention being paid to surface structure for signal loss-mitigation/ coarse properties. Yet we still lack standards references as to what the actual copper grain structure should look like to optimize microvia reliability, what Financial Risks of Ignoring Copper Grain

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