Open Access

Marvin Friedl

• Setting up a measurement system capable of automatically measuring low resistance plated via holes of unpopulated circuit boards during a reliability test is the goal of this thesis. It should be possible to carry out up to 30 resistance measurements at the same time, while the circuit boards are stored in a climatic chamber to carry out a thermal cycling test. In addition, the measuring system must provide a measuring current of 1A trough the plated via holes. The focus was to find a suitable low resistance measurement method and an appropriate circuit scheme for switching between several circuit boards. In addition, attention was paid to scalability to increase the number of measurements if necessary. Furthermore, a user interface should simplify and track the control of the measurement. During the investigation, the constant-current method combined with the four-wire measurement method is best suitable for the use case, as shown in Section 2.1 and Section 3.2. The constant-current method was implemented with an external current source and a voltmeter, as described in Subsection 2.1.1. The voltage drop across the plated via holes, which occurs because of the provided current flow of the constant current source, is measured with the voltmeter. The current in series to all DUTs circuit switching applications was chosen to implement the measurement system, as explained in Paragraph 6.1.1.1. Due to the measurement methods and circuit applications investigated in the thesis as well as the practical presentation of the measurement system, it is possible to carry out automated low resistance measurements on plated via holes of circuit boards.