Study of Bimetallic Corrosion and Its Inhibition Strategy for Cu Interconnect and IC Packaging Using Micro-Pattern Corrosion Screening
In this paper, a new corrosion screening metrology utilizing micro-corrosion test patterns provides rapid in-situ corrosion evaluations relevant to Cu interconnect structure and IC packaging. In CMP related chemical environments, the Cu corrosion was found to be accelerated through an oxygen reduction reaction catalyzed by Ru contact – a potential new liner for Cu ECD. The corrosion screening discovered pyrazole is a more effective Cu corrosion inhibitor than commonly used benzotriazole (BTA) in highly alkaline TMAH solution. Relevant to Cu wire bonded assembly, microscopy time lapse imaging, SEM, EDX, and Tafel plot were employed to study Al/Cu bimetallic corrosion in acidic chloride solutions. Micropattern corrosion screening helps to identify the root cause of Al pad corrosion that leads to Cu ball lift-off in Cu wire bonded device, a fatal defect. Complete corrosion inhibition can be achieved by strategically disabling the mutually coupled cathodic and anodic reaction cycles.
Sunday, Sept. 20, 2015, 8 a.m. — Tuesday, Sept. 22, 2015, 10 p.m. CT
Austin, TX, United States
Technical conference and networking event for SRC members and students.