Keysight Technologies B1505A, Configuration Manual

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5-52 Keysight B1505A Configuration and Connection Guide
Connection Guide for Wafer Prober and Your Own Test Fixture
About Cable Connections
To Make Connection to Measure Low Resistance
When you measure a low resistance, high current flows through the DUT. This high current
increases the measurement error caused by the residual resistance of cables. To cancel the
effect of this resistance, you can use
Kelvin connections (4-wire), which means the Force
and Sense lines are extended separately to the DUT.
Connect the probing needles to the coaxial cables as shown below:
1. Cut and trim end of the coaxial cable such as N1254A-503 and N1254A-506, so that
the center conductor does not touch the outer conductor (connected to the guard
terminal).
2. Connect the center conductor to tail of the probing needle. Never connect the outer
conductor to the probing needle. However the outer conductor should be extended as
close as possible to the probing needle.
3. Connect the outer conductor to the outer conductor of the probing needle if it is a
coaxial probing needle.
4. Perform 1 to 3 for both Force and Sense lines.
5. Contact the probing needles for the Force and Sense lines as close as possible to the
DUT.
Example
The following example connection can be used to measure low resistance. The Sense line
is extended to the probing pad, and contacts the Force line through the pad, so the voltage
drop due to the residual resistance caused by cables and wires is canceled.
Kelvin Connection
Kelvin connections give good measurement results when you force high-current. The
following figure shows the equivalent circuits for Kelvin and non-Kelvin connections.
Probing needle
Outer conductor
Center conductor
Coaxial cable
Contact pad
Contact pad
(a) non-Kelvin connection
(b) Kelvin connection
r
F1
r
F2
R
DUT
r
S2
r
S1
V
V V
r
F1
r
F2
R
DUT