A method of investigating fine shorting whiskers within a leadframe molded package

A potential method to investigate fine whiskers which cause electric shorts between adjacent leads in a plastic molded leadframe is discussed. This technique uses mechanical milling and excimer laser etching to expose the fine whiskers within a packaged module. The combination of these two processes enables us to expose the fine whiskers without changing the position or composition. Subsequent material analyses can then be applied, and the process step by which the whisker was introduced can be determined. This method has also been applied in analyzing various soldering levels of a hybrid integrated circuit (IC).