There is an additional test that will be used from 11.03. on all HDIs. It involves measuring the voltage between ground and the HV pin of the needle card with the goal of checking whether proper voltage is delivered to the HDI. The HDI testing script has been updated and it now prompts the user to set the voltage to -800 V, measure the voltage on the pin and write this into the test results. After this, another instruction has been added which tells the user to raise the Z-stage (needle card) before setting voltage to -1100 V. This is done to prevent sparking from the HV pad to the HV pin if the alignment is slightly off.
While measuring the voltage on the HV pin, one should keep in mind the proper settings on the Keithley. When the voltmeter probe is connected to the pin, the current reading on Keithley will go up and if the current readout range is low, it will limit the voltage even before hitting compliance. This was observed during the initial testing of the new procedure. Range should be set to maximum (100 muA) and compliance should be set to 105 muA. This is high enough that it is not reached while measuring voltage at -800 V. |