Development of a Dry-contact Ultrasonic Technique and Its Application to NDE of IC Packages

Theory and applications of high frequency broadband ultrasound via a thin layer in contact with a solid

“…The dry-contact ultrasonic technique has been proposed for transmitting high frequency broadband ultrasound through a solid/solid interface (Tohmyoh and Saka, 2002). In this technique a thin layer is inserted between the water and the solid sample.…”

“…The idea of introducing the pressure is highly valuable. To transmit high frequency broadband ultrasound through a thin layer into a solid sample, the dry-contact ultrasonic technique has been developed (Tohmyoh and Saka, 2002). In this technique, the air at the interface between the layer and the solid sample has been evacuated by a vacuum pump and a pressure of about 0.1 MPa is applied to the interface to improve the acoustic coupling at the layer/sample interface.…”

OS02W0151 An effective transmission technique of higher frequency ultrasound into a wafer level package

“…However, the higher frequency ultrasound re-quired for performing the high-resolution package inspection is not yet available for the aforementioned techniques. In contrast with these techniques, the dry-contact ultrasonic technique can transmit the higher frequency ultrasound into the packages through the thin solid layer inserted between the coupling liquid and the packages [13,14], and can realize the high-resolution package inspection [15]. The dry-contact technique uses the coupling liquid, but the package is protected from being wet by the layer.…”