A Real-Time, High-Resolution Sensor for Bond Integrity and Thermal Conductivity

Dense, high-performance electronic systems employ advanced substrate materials, such as ceramics, for maximum heat dissipation. During the fabrication of these ceramic packages various thick-film and thin-film materials are bonded to the substrate and subsequently serve as circuit paths and attachment points for the integrated circuit die. Rapid, high-resolution bond integrity measurements must be made at the earliest stages of this manufacturing process to reduce srap and rework costs and to ensure that the desired lifetime and performance goals are met. We propose to develop an in-process sensor that uses optical thermal conductivity measurements to detect bond micro-flaws. The optical character of the proposed instrument makes it possible to achieve high resolution at the long working distances required to support certain manufacturing processes (e.g., furnaces). A byproduct of this approach is that detailed thermal conductivity maps are produced for eacg manufactured part, which makes possible closed loop control of thermal conductivity properties in addition to defect detection.