Research On Ultra-high Frequency Ultrasonic Microscopic Measurement System

Ultrasonic microscopic detection technology is an effective method to detect theintegrity and reliability of electronic packaging and micro-mechanical components.Ultrasonic microscopic detection technology has the advantage of non-destructive, rapidand high-precision. Based on the current situation and development trend that electronicpackaging are increasingly integrated and micro-mechanical components are becomingincreasingly small, the structures and defects needed to be detected are getting smaller sothe resolution of detection system needs to be improved. Therefore, the development ofhigh frequency, high precision and high resolution ultrasonic microscopic measurementsystem is imperative.In the paper, based on the resolution and accuracy requirements of high frequencyultrasonic microscopic measurement system, an ultra-high frequency ultrasonic excitationand reception system is built. The operating frequency of the system is50MHz~500MHz.The method of data acquisition and transmission by oscilloscope is studied. In order toachieve remote control of the oscilloscope, a PCIExpress high-speed card is used to connectthe oscilloscope to the computer. In the scanning process, the position comparison functionof the motion card and the segmented memory acquisition mode of the oscilloscope areused to increase the scanning accuracy and speed.A softeware system is designed and programmed to realize ultra-high frequencyultrasonic microscopic scanning. The softeware system consists of a data acquisitionmodule, a motion control module, a microscopic scanning and imaging module and amicroscopic measurement module. In the scanning process, the C-scanning image isdisplay in real time and several kinds of imaging modes and drawing modes are available.The scanning result can be stored for post procession in the software. The principles andalgorithms of lateral dimensional measurement based on C-scanning image andlongitudinal dimensional measurement based on A-scanning waveform are studied.Some experiments are carried out to microscopic scan several samples by using theultra-high frequency ultrasonic microscopic measurement system. The result data andimages are analyzed. The resolution of the designed ultrasonic microscopic measurementsystem is verified.Compared to the conventional ultrasonic microscopy systems, the ultra-high frequency ultrasonic microscopic measurement system designed in the paper has higher operatingfrequency, higher precision and higher resolution, and can dectect much smaller structuresand defects.