Exploration of electromigration within PbSn solder bumps

Task

The effect of electromigration in PbSn solder bumps is examined in detail by this test bed. Mechanical and electrochemical effects are expected which may influence the functionality of the bumps and result in a total outage. (Photo: Fraunhofer IZM)

Requirements

• Design of the test assembly with two independent measurement chains, controlled by one and the same software
• Implementation in two separated climatic chambers for independent cycle tests
• Wiring temperature stability over 100°C
• Measurement data aquisition with 120 channels
• Measurement accuracy better than one milliohm
• Verification and storage of the measurement data on the PC
• Automatic searching and short-circuiting of defective test samples
• Optional shutdown of a chain for withdrawing or replacing test samples
• Simple adaption of the software for future requirements
• Off-line data analysis with commercial software

Solution

Writing of the measurement application with LabVIEW (National Instruments). Controlling of the measurement devices (Switch System / DMM from Keithley Instruments) via GPIB. Strict separation of the software modules for both chains. The evaluated measurement data are saved as spreadsheet ascii file.