TY - CHAP A1 - Tremmel, Florian A1 - Nagler, Oliver A1 - Kutter, Christoph A1 - Holmer, Rainer T1 - Smart Cantilever Probe with Integrated Force and Acoustic Emission Sensor T2 - 2023 IEEE SENSORS, Vienna, Austria, 10/29/2023 - 11/1/2023 N2 - Acoustic emission (AE) testing recently found its application in the wafer testing sector of the semiconductor industry. To find out the mechanical robustness of semiconductor devices, contact pads on the chip surface are intentionally overstressed with an indenter tip and the appearing oxide cracks are detected with help of the generated AE signals. This is done in a customized test bench with a patented sensor-indenter system. This paper presents an improved version of the measurement setup that solves certain disadvantages of it and can be used in a standard wafer prober. The main components of the developed sensor system are a strain gauge for contact force measurement and a piezoelectric sensor element for AE signal detection. Both components are integrated on a cantilever beam which has an exchangeable indenter tip at its free end. The cantilever probe is electrically conductive to enable electrical tests via the indenter tip. This smart sensor-cantilever combination (SCC) can be mounted with several adapter components on a carrier plate to place it in a wafer prober. For both sensor elements amplifier circuits are developed to enhance their signal-to-noise ratios (SNRs). A prototype setup is shown together with simulated and experimental results to demonstrate its performance. The mechanical properties of the cantilever, as well as the force sensor and the AE crack signals, already fulfill the requirements for an implementation in a wafer prober. To further improve the sensor resolutions and detection limits, several optimizations regarding the design of the SCC are in progress. KW - Acoustic emission testing KW - piezoelectric sensor KW - strain gauge KW - operational amplifier circuit Y1 - 2023 SN - 979-8-3503-0387-2 U6 - https://doi.org/10.1109/SENSORS56945.2023.10325021 SP - 1 EP - 4 PB - IEEE ER - TY - JOUR A1 - Tremmel, Florian A1 - Nagler, Oliver A1 - Kutter, Christoph A1 - Holmer, Rainer T1 - Mechanical robustness analysis of semiconductors with a single needle probe card using acoustic emissions JF - e-Journal of Nondestructive Testing N2 - The combination of indentation testing and acoustic emission (AE) is widely used to analyze the fracture toughness of test substrates. In the manufacturing of semiconductor devices this material parameter also plays an important role. During the so-called wafer testing inside a wafer prober small probe tips are pressed onto the chip surface to check its performance. To prevent damaging the chip by that, the fracture toughness and load limit of it has to be defined in a prequalification step. This paper presents a test system that imitates the wafer testing process as close as possible and uses acoustic emission to detect appearing cracks and thereby also the load limit. The frontend of the test setup consists of a modular single needle probe card which can be placed in a wafer prober. Also, the indenter properties (tip diameter, stiffness, etc.) can be adjusted to the probe used later on during productive wafer testing to ensure realistic probing conditions. A piezoelectric sensor and a full strain gauge Wheatstone bridge are implemented close to the single indenter to measure the AEs and the applied contact force respectively. The signal-to-noise-ratios (SNRs) of both sensors are improved with an own analog amplifier module before recording them with an USB oscilloscope. A developed measurement software (LabVIEW) is used to adjust measurement parameters (trigger limit, record length, conversion factors, etc.) and automatically store and separate measurement data from different acoustic events and imprints. To evaluate the result files a second software tool (MATLAB) reads the files out and clusters the recorded events to separate crack signals from electrical and mechanical disturbances. With a prototype first test results are generated and the functionality and accuracy of the measurement concept is proven. KW - Acoustic Emission KW - Crack probability distribution KW - Fracture load limit KW - Wafer testing Y1 - 2024 U6 - https://doi.org/10.58286/30254 SN - 1435-4934 VL - 29 IS - 10 PB - NDT.net ER -