This is a very common problem in the industry and you are not alone.  We see
this condition mostly with a heavy weave construction on half ounce, or
below, copper.  if you are currently laminating in the wide direction, turn
the panel so that you are laminating a shorter width.  This will increase
your lamination pressure without changeing any parameters.

Check your lamination pressure by taking a resist coated panel and putting it
in between the rolls of the laminator with full pressure on.  Stop the
laminator for 60 sec. to cause resist separation.  This will give you a foot
print of the lamination pressure.  It should be even across the footprint.
 If not, the pressure, rollers or laminator needs attention.  If the foot
print is straight try increasing the pressure and repeat the foot print test.
To fill the weave pattern, higher pressure is usually better as long as you
don't deflect the laminator's rollers.   Becareful, this may adversely affect
your tenting of the resist. 

Surface prep may contribute, but ususually pumice is the best unless you are
leaving some behind due to poor rinsing.

Tape test after image should show no signs of resist lilfting.  It should be
stuck good.

In general, increase you lamination pressure (within reason), use a finer
weave against the cap copper, and put more steel between panel during
pressing.
Good luck!
Ken Bridges - Morton

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