Split Force-Sense Four-Point Resistance Measurement
Original Publication Date: 1985-Sep-01
Included in the Prior Art Database: 2005-Feb-19
A modification has been made to test equipment used for measuring low resistances which cancels out thermal electromotive forces (EMF) generated in such instruments. This results in much greater accuracies when making resistance measurements for the C4 (controlled-collapse chip connection) in semiconductor manufacturing processes. It has application wherever extremely low resistance (less than 10 milliohms) must be measured. This method was implemented on a Fairchild Series 80 tester. In the conventional 4-point system, which is illustrated in Fig. 1, force and sense lines from relay 2 and relay 3 are used for measuring the load. With this method, Vmeter = Vrelay2 + Vresistance - Vrelay3. The tester's voltage measuring instrument was rewired, as illustrated in Fig.