Negatory, I'm afraid. The spell description states specifically that it DOES block etherial creatures.
It then goes on to say that an etherial creature could "get around" the wall of force, say by floating over it, or by passing through the ground under it.
However, if you form a wall of force into a sphere around an etherial (or incorporeal) being that's in midair, it cannot escape without somehow destroying the wall, or by using an ability like Dimension Door or Teleport (which shunts through Astral space, which force effects do not extend into).
