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AUGUST 2026 I I-CONNECT007 MAGAZINE 101 etch in one tank; however, separate steps are generally more effective. As the glass etch weakens with use, its ability to frost or rough- en glass fibers decreases, reducing catalyst adhesion to glass and increasing the likeli- hood of voids. This about covers the pre-electroless copper causes of voiding. In another column, I will explore other causes of voiding. I-CONNECT007 Michael Carano brings over 40 years of electronics industry experience with special expertise in manufacturing, perfor- mance chemicals, metals, semiconductors, medical devices, and advanced packaging. To read past columns, click here. T RO U B L E I N YO U R TA N K Hydroxide increases the aggressiveness of permanganate's attack on the resin, while per- manganate in the +7 oxidation state oxidizes and breaks down the resin. Manganate (+4), a reaction by-product, does not contribute to resin oxidation and should be controlled below 20–25 grams per liter. If manganate builds up, resin removal and texturing will slow. If solvent compatibility and penetration are adequate, consider increasing the per- manganate concentration. Sodium perman- ganate can provide more available perman- ganate in solution than the corresponding potassium salt. • Review the neutralizer and glass etch. A major source of voiding is manganate residue left on the resin and glass within the hole wall. Renew the solution regularly to maintain ac- tive chemistry, and verify the acid concentra- tion because low acid reduces neutralization effectiveness. To reduce process steps, some fabricators combine the neutralizer and glass Figure 4: Desmear performance with microroughened texture to the resin.