Vivek,
      I will send you a more detailed report directly to your email.  The first
step is to produce the correct adhesion promotion between the aluminum and the
resist.  Most engineers use the wrong prime time in their vacuum vapor primer
for metallic layers.  the correct time is usually a prime time of 20 minutes
instead of 5 minutes prime time.  This will produce the best molecular layer to
give an organic/inorganic bridge.  With the total removal of water molecules in
the vacuum dehydration you will have no molecules close to the etch wall that
moisture can affect by lifting off the resist.  The correctly primed surface
will remain hydrophobic.  Then the resist will stick to the modifies hydroxyl
ions and the etch will only attack the open aluminum surface with no chance of a
water molecule break down.  The good news is you can test it free.  Correctly
primed surfaces will withstand weeks in outside humidity with no break down.
Ship me some wafers I will prime you will etch.  Hopefully with not problems.
Most of our wet etch experience with hundreds of units in the field is with a
phosphoric/acetic mixture.  Why are you using HCl.  Bill Moffat