Leakage Current on PCB surface

[jayakrishnanj]

Hello Friends,

I am a PCB Designer Engineer, part of Hardware design which as IGBT (TO package) used, For testing purpose we applied 15V at Gate and Emitter by just connecting the IGBT with wires, Ig shows 20nA, 1uA p-p which is normal, but with same input connected on Bare PCB we Ig10uA and 250uA P-P, we are using FR4 PCB material (IPC class 2), TG 180, Can anyone explain the reason for this leakage current when connecting IGBT mounted on Bare PCB?

 

[aliarifat794]

Clean the PCB thoroughly to remove any manufacturing residues or contaminants.

 

[jayakrishnanj]

Clean the PCB thoroughly to remove any manufacturing residues or contaminants.

Thank you for your solution, We already tried that option, still the result remain same.

 

[KlausST]

Hi,

leakage current not only is a function of material, but also of voltage, dirt, trace lengths, creepage distances, humidity, temperature...

Also mind: a freshly made PCB may have increased leakage current when the epoxy still is not cured 100%.
Try baking the PCB to faster cure the epoxy.
For sure cleaning is important for "surface related" leakage currents.

You talk about peak-peak currents. ... Mind these may also be caused by capacitive coupling and thus have nothing to do with true (resistive) leakage currents.

Klaus

 

[std_match]

10 uA and 250 uA p-p ? What is the frequency of the 250 uA p-p?
Please show the measurement setup.
It seems that you have some external signal disturbing your measurement.
A large AC-coupled signal may be rectified somewhere, so it appears as a DC signal.