Method to Mitigate BEOL Process-induced Device Charging
Publication Date: 2010-Apr-20
The IP.com Prior Art Database
Process for Mitigating Charging Damage
Method to Mitigate BEOL Process -induced Device Charging
It is well known that RIE etch and other plasma processes can cause damage to transistors, such damage being
manifested as gate leakage, threshold shift, premature dielectric breakdown, and other phenomena.
It is advantageous to avoid RIE steps when possible, but of course to achieve tight dimensional control
these processes are legion in semiconductor processing. In some cases, however, a careful
evaluation of the specific dimensions and processes involved may offer the opportunity to mitigate
the damage by using the RIE only were needed, and avoiding its use in the specific damaging step.
By stopping the RIE etch step before the TiN etch-stop layer is fully cleared, the remaining film may be removed
by a short wet etch. The charging damage is prevented by such a process sequence because the conductive TiN remains
in place to shunt any potentially damaging current during the RIE step, and the subsequent wet etch does not cause
any charging damage.
The following figure shows the standard process and the process taught in this invention:
A more detailed schematic step-by-step exposition follows:
The data resulting from the new and old process sequence clearly show the improvement in charging damage.