Looking for an old anime

I'm looking for a very old anime where this kid created a female robot

I remember in an episode (final episode?) the female robot has to merge / fuse its AI with the Earth's system in order to save the world, losing its physical form.

Thanks!

Kowaremono

I believe the anime you are thinking of is called "initial D"

Only thing that sounds remotely close is Chobots, and that loses because he doesn't built the robot.