Plug in the source measurement unit (SMU), LCR meter (LCR) and ammeter (AM) according to the figure below.
Plug in the USB connector. The switch card should power up automatically.
Manual controls of the switch card
The LED display should show '---' which indicates that all channels are shorted to GND.
The two central control sticks allow to change the open channel. The default visualisation mode is the octal numeral system, i.e. the channel numbering runs from '000' to '777'. See figure below.
First tests of the card
To test the functionality of all the MUXes, you can measure the capacitance at 1kHz and 0V bias. This can be done anywhere, e.g. on a table.
The result should be a step like structure with 3 periods of 8, similar to the figure below. Average capacitance should be somewhere around 120pF.
If you see a step structure but values well below 100 pF the measurement frequency is too high.
If you see a step structure but values well below 100 pF for some channels, most likely one of the MUXes is not working correctly. The structure of the capacitance results can tell you which one. It is likely that the MUX is either broken or, if an early version of the card is used, that one of the pull-up resistors on the legs of the switches (bottom side to the MUX) is not soldered correctly.
If you see values well below 1 pF, you are most likely creating aground loop somewhere outside of the setup or, if an early version of the board is used, resistor R579 is not removed.
Integration with the mounting frame
The pogo pins require quite some weight to be fully compressed. The pressure should be uniformly distributed throughout the sensor area. A mechanical frame with an array of (electrically isolating) standoffs is used for this.
Mount the probe card on the frame. Make sure the number of standoffs is sufficient and they are uniformly distributed.
Mount the switch card.
Mount the system to the platen of your probe station.
To ensure a good and uniform contact it is essential that the platen and frame that holds the probe card and the chuck are as parallel as possible.
Getting Started with the Probe Card
Electrical connections to the probe card:
Plug in a manual manipulator to the LEMO connector on the back of the probecard.
Bring the HV to the chuck. You can use the screw terminal on the HV area of the probe card (rear left on the bottom side). You can also solder a triax connector to this region if required.
Further tests of the card
Contact the chuck with the pogo pins. Measure the current at 1V. The total current should be around 25 uA (40k total resistance).
Check that each channel draws approximately the same amount of current, somewhere between a few tens to hundred nA depending on the number of channels.
Unconnected or broken channels will show zero current.
Getting Started with Sensor Measurements
Load a sensor to the chuck.
Use a microscope to through the view holes on the PCB's. Look for alignment marks and align for angle, x and y position.
Carefully lower the platen/lift the chuck.
Compress the pins to about 2/3.
Contact the guard ring with the external positioner. Make sure you know how and where to contact the guard ring.
A detailed description of the contact procedure is described here.
Further tests with a sensor
Forward bias the sensor and measure the current per channel again. Make sure every channel is well contacted.
Understanding the Electrical Circuit
The current runs via the coax signal and returns via the shield to GND.
A large bias resistor is used to increase the impedance of the electrical circuit parallel to the channel-under-test. You can set the value to 8 discrete steps between 100k and 100M. Choose it wisely depending on the capacitance of the pad and the AC frequency you want to use.
For 50pF, somewhere between 1 and 5 kHz is a good value. See this publication (NIM A or arXiv) for further details.