Bias Testing

Testing Bias Bonds

Description:

After bias bonds are done, and before doing any other bonds, one should do the following:

Testing Sequence:

Position the part on the probe station copper plate according to its layer, direction, and side (e.g., "L3FZ" marks on the plate are for layer 3 forward DFA's, z side up). Connect the bias connector, and close the lid.
On UCSB5, click on theMain###.llb icon in the row of SVT lab icons normally displayed in the right hand corner of the screen, which will open the Main Control vi automatically.

1). Run the I_Leakage vs. V_Bias test. Select "I_Leakage vs. V_Bias" in the "Test" window in the upper left hand corner of the Main Control panel.

Settings: Start Voltage = 0V

End Voltage = 60V.

Step Size = 2V.

Things to look for:

1. Total current should never reach 20 uA (current limit of supply).

2. Bias + Guard currents should be equal to Total Current.

3. If Bias and Guard currents are identical, there is probably a short between the bias and guard lines. Check the Upilex for shorted traces and check the wirebonds on the silicon.

After the test is finished: print out the front panel of the vi if it was not done automatically, and put it in the part's binder.

2). Run the "I_Leakage vs. Time" test. Select "I_Leakage vs. Time" in the "Test" window in the upper left hand corner of the Main Control panel.

Settings: Time = 12 hours (usually).

Delta(t) = 0.5 minutes.

Bias Voltage = 60V (if the part did not hit the current limit at 60 V from the previous test (I_Leakage vs. V_Bias)).

Things to look for: the current should probably be stable after 12 hours. If it is steadily increasing, this could be a problem.

After the test is finished: print out the front panel of the vi if it was not done automatically, and put itin the part's binder

After testing is done, enter the corresponding entry into the DFA database!

The data from a given test should be located in \\ELECTRON\babar\svt_lab\DfaTests\DataLogs\, under the part directory (e.g., for D02B.10 the directory will be d02b10). There should be a directory there called r###### (r stands for "run", and the 6-digit number is the run number which is also displayed on the front panel of the Main Control vi during the run). This directory, in turn, should contain four files: r######.cur (bias, guard, and total currents), r######.dat (data depending on the test), r######.env (temperature and humidity), and r######.inf, with some information about the run.

People to ask if problems arise:

Doug Roberts

Philip Hart

Sam Burke

Jeff Richman