Issue link: https://iconnect007.uberflip.com/i/819981
May 2017 • The PCB Magazine 89 Possible Causes: a) Improper lamination process. b) Too little resin content in the laminate. c) Improper drilling parameters. d) Improper glass-etch process. 4. Hole-wall Pullaway Description: The plated copper bulges out from the resin area on the hole wall. Characteristics: Can lead to barrel cracking and can be brought on by inadequate texturing of the resin of the hole wall. Possible Causes: a) Too much solvent absorption caused by solvent parameters being set too high. b) Too much solvent absorption caused by permanganate parameters being set too low. c) Under-cured laminate. d) Laminate that can not be properly textured by using permanganate desmear processes. 5. Interconnect Defect Caused by Drill Smear Description: A fine line seen between the in- nerlayer and the plated copper when no posi- tive or negative etchback is seen. Characteristics: Interconnect defects can cause opens. Possible Causes: a) The desmear parameters are set too low. b) Improper drilling parameters. c) Improper metallization processing can cause similar-looking defects. Figure 5: More examples of wicking. Note torn out glass bundles, the most common effect. (Source: IPC 9121 Process Effects Guide) Figure 6: Hole-wall pullaway. Note a blister or bulge of the plated copper from the sidewall of the via. THE DESMEAR DEFECT GUIDE