Anion Reaction for Failure Analysis of Microcircuit Components

AN ANALYTICAL technique for failure analyses on complex interconnected integrated circuits has been developed by employing the selective reaction of certain chemical components with metal interconnections. This technique has proven to be particularly useful in investigating failure due to the following: a. Pinholes in metal-oxide-semiconductor capacitors b. Poor or marginal contact of metal to silicon substrate c. Pinholes or weaknesses in the oxide under metalized areas d. Microscopic breaks in interconnections. The experimental approach is based on the concept of reacting the interconnection metal with an anion which is attracted to electropositive regions and remains unreacted due to repulsion over electronegative metal regions. Illustrations are presented herein consisting of anion reaction patterns on interconnected circuits showing the usefulness of this technique in the determination of poor or marginal capacitors, contacts and interconnections.