particle system collision to Plane

Hi :

I try to study how to do the collision between the particle system and a single plane.

The single element of particle system named cube, I set cube as rigid body (active) ,and also I set up the particle system Namede emiiter . also i set up the single plane ,as rigid body(passive) and also I enable physics for the collision .

Now the particle system can collision the plane, But one problem is that each element will intersect or penetrate the plane.

I do not know where I set wrong. I do not want any penetrate.

anyone can help me?