A New Plasma Process for Surface Treatment prior to Wire Bonding that Utilizes the Sublimation Effect of Alkyl Group Radicals
Conventionally, argon plasma has been used as a method of improving wire bonding performance by removing contaminants (nickel, nickel oxides, and impurities concentrated on the gold surface) from the gold bond pads after the die-bond cure process. The sputtering effect of argon plasma is the primary mechanism by which contamination is removed, and as a result this technique has some problems such as excessive thinning of the gold bond pads. In order to avoid these negative side effects, we developed a new plasma process for surface treatment prior to wire bonding. This new plasma process uses a methane (CH4)/hydrogen (H2)/Ar mixture, which selectively removes the contaminants from the gold bond pads, primarily through the sublimation effect of alkyl group radicals generated from CH4. This new process improves wire bonding performance by removing contaminants efficiently.
- Japanese journal of applied physics. Pt. 1, Regular papers & short notes
Japanese journal of applied physics. Pt. 1, Regular papers & short notes 42(11), 7112-7115, 2003-11-15