| 摘要 |
PURPOSE: Metal surfaces, particularly copper surfaces, which are oxidatively micro-etched to increase surface area, are provided acid-resistance by exposure to a thiazole compound and/or a thiocarbamide compound. The thiazole compound and/or thiocarbamide compound may be provided either in the oxidative micro-etching solution or provided in a post-micro-etching solution. CONSTITUTION: There is provided an oxidative aqueous etching solution for micro-etching metal surfaces so as to increase the surface area of the metal surface and at the same time provide acid resistance to the micro-etched metal surface. The solution contains a proton source; an oxidizer agent; an azole compound; a source of halogen ions; and a compound selected from the group consisting of a thiazole compound, a thiocarbamide compound, and mixtures thereof. This solution is used to micro-etch a metal, e.g., copper, surface. Very substantial improvements in acid-resistance is achieved through inclusion of the thiazole and/or thiocarbamide compound as evidenced by significantly longer times that it takes for an HCl solution to change the color of a micro-etched board from brown to pink. This improved acid resistance translates to elimination or minimization of "pink ring" in the formation of multi-layer printed circuit boards and elimination or minimization of other acid attack related problems in printed circuit board formation. A metal surface is oxidatively micro-etched. Subsequently, the surface is post-treated with an aqueous solution of a thiazole compound, a thiocarbamide compound or a mixture thereof, the thiazole and/or thiocarabamide compound being provided at a level of at least about 0.01 wt%, preferably at least 0.2 wt%, up to saturation level(s).
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