Issue link: https://iconnect007.uberflip.com/i/1503998
58 PCB007 MAGAZINE I JULY 2023 employ plasma desmear. Indeed, many firms in the industry today utilize a combination of plasma desmear and chemical desmear (alka- line permanganate) to ensure a target pad free of any organic by-products. Another example of debris is shown in Figure 3. While this certainly adversely affects long- term reliability, the defect can be remediated with proper attention to the laser via formation process and desmear operation. In my ne x t co lumn , my di s c u s s ion w i l l focus on metallization—conventional electro- less copper and direct metallization as an alter- native. PCB007 Michael Carano brings over 40 years of electronics industry experience with special exper- tise in manufacturing, perfor- mance chemicals, metals, semi- conductors, medical devices, and advanced packaging. To read past columns, click here. of an improper or neglected desmear process where residual epoxy from laser drilling is still present and presents an unreliable hole con- nection. In Figure 2, one can see the separation of the plated copper from the target pad. A pos- sible solution to this situation would be to Figure 2: Resin remaining on the pad. Figure 3: Remaining residues after laser via formation. Residues are clearly evident on the pad.