Local dynamics at a superattracting fixed point of a polynomial is well
understood via the Bottcher coordinate; the polynomial is analytically
conjugate to its term of lowest degree on an open neighborhood of the point.
We generalize this theorem to that of a polynomial skew product; if the map
has suitable weight for a superattracting fixed point, then an analogue of
the Bottcher coordinate exists on some open set, whose closure contains the
point.