  Based on experiments and 3-D simulations, we show that a soft elastic film
during adhesion and debonding from a rigid flat surface undergoes morphological
transitions to pillars, labyrinths and cavities, all of which have the same
lateral pattern length scale, close to \lambda/H ~ 3 for thick films, H > 1
micrometer. The linear stability analysis and experiments show a new thin film
regime where \lambda/H \approx 3+ 2 (\gamma/3 \mu H)^(1/4) (\gamma is surface
tension, \mu is shear modulus) because of significant surface energy penalty
(for example, \lambda/H = 6 for H = 200 nm; \mu = 1MPa).
