Eagle configure autorouter to solder components (except vias) only on bottom layer of double sided PCB
While I have to agree with the previous answers - you are indeed a lot better off in the long run if you route manually, I feel your question has not really been properly answered.

A quick-and-dirty workaround for you might be


copy the component(s) to a library of your own
add a new package, in which you put a GND rectangle around the entire component on the top layer only
in the circuit, replace the original component with your tampered component
let the autorouting commence
go back to your circuit, and swap the component back to its original package.


Now, before the rotten-egg-throwing sets in, a few extra words why you should not do that.

While Eagle takes quite a bit of effort to get the hang of, it is definitely worth practicing these things on simple designs. As you advance, you will get to the point where you have to route manually, because some signals must be laid out in certain ways. There might still be workarounds for each specific problem, but you will never have practiced to place the components in a way that it is possible to route with minimal effort and losses.