Potential failures after Temperature cycle

[Joeest]

Hi,

I found few devices fail after the Temperature cycle test. Can it be caused by overstress wire bonding? May I know which areas should I concentrate for FA? Those units shown very low Vgsth values.

Thanks.

[dvaidr]

Vgs(th) - I take it you're manufacturing and developing MOSFETs.

It's a diffifcult one really. I guess it could be down to bonding or manufacture in general.

Have you carried out any thermal impedance tests?

Are you using solder preforms on substrates?

Have you carreid oout any shear/pull tests on bonds?

Is the temperaure calibrated, i.e. is 150C really 150C wtc etc.

Anything would be a guess at the moment. :(