Slide 1

Measuring Leakage Current on Singles and Ladders P. Riedler and S. Ceresa, August 2005 Sensor Chip Manipulator Needle for sensor back side contact Probe-card with contact needles for chip Apply +50V on sensor back side via needle Ground sensor front side via chip contacts (-> probe-card)

Slide 2

Probe-card Manipulator arm with needle Sensor back side Probe-card needles

Slide 3

Check-list: The probe-card is installed correctly. Cables J1 and J2 are connected to the probe-card and on the other side to the MB card. The connectors on the cables are labeled as well as the connectors on the probe-card. On the MB side the connector names are on the large PCB: J1=J1, J10=J2. The 5 cables from the MB card should be connected to the Gossen power supply. The manipulator coax cable should be connected to the filter (lemo connectors with capacitors and resistor). The filter should be connected on one side to the Keithley (inner conductor=> +, outer conductor => -) and on the other side to the lemo cable soldered to the probe-card.

Slide 4

MB card Cables J1+J2 Probe-card The probe-card is connected via cables J1+J2 to the MB card. The MB card is connected to the Gossen power supply:

Slide 5

Contacting the chip After the first contact the chuck needs to be moved up by ~ 80-100 microns to ensure a good electrical contact: 1st contact: Needles barely touch the pads Good el. contact (1st contact + 80 microns): Needle marks are clearly visible

Slide 6

Chuck settings: SET ALIGN to -500 microns (important to avoid damage to the probe card!). SET SEPARATION to -1000 microns. Once the contact point is found the CONTACT should be SET. The same contact setting can be used for all chips unless the prober is switched off in between.

Slide 7

Gossen Power Supply (Chip): -5V ~ 100mA +5V ~ 600mA +5V ~ 1A The cables should be connected correctly and the three outputs should be adjusted to 5V (checked April 05). The expected current consumption of the 3 outputs is indicated above. Gossen power supply with cables to the MB card MB card Cables After contacting the chip with the probe-card needles the power supply can be switched on:

Slide 8

Sequence - SWITCH ON: Position single/ladder on vacuum chuck. Contact the pads of the chip with the probe-card needles (see previous slides). Contact the back side of the sensor with the manipulator needle. Switch on the Gossen 3x5V power supply.

Slide 9

Switch on the PC and VME crate Start ALICE PTS Labview program located on the desktop. Select Initialize and Initialize VME from the menu of the ALICE PTS window. This will start the VXI resource manager. Once it finished, click OK. Go back to the ALICE PTS window and click Initialize JTAG and Initialize MB. A red LED on the MB card will come on. Switch on the Keithley 2410. Increase the bias voltage (Keithley) up to 50V and measure the leakage current (Keithley). Sequence - SWITCH ON continued:

Slide 10

Sequence - SWITCH OFF: Warning: do not disconnect the needles with the power supplies switched on! 1.Decrease the bias voltage (Keithley) to 0V. 2.Switch off the Keithley 2410 power supply. 3.Switch off MB card using black switch on the PCB. 4.Switch off the Gossen 3x5V power supply. 5.De-contact the manipulator needle. 6.De-contact the chip by moving into ALIGN position.