How do I train my Australian Shepherd to stay within the boundaries of our yard?

I have a 5 year old male Australian Shepherd. I live in the country on a busy road. When he was about a year old he broke his tie out and I had to rescue him from the Human Society with a ticket to appear in court for failure to confine my dog (even though he broke his tie out, dragging 10 feet of lead and having his tags, I still got fined). I have kept him chained when he is outside. I have unchained him to try to play ball or catch with him but everytime he takes off to the neighbors orchard and field. He always comes back but I am afraid of him chasing a rabbit, squirrel or cat into the road and being picked up again by the Humane Society or hit by a car. I bought a dog chain linked dog kennel with a dog house but he undoes the gate and let's himself out. How can I train him to stay within the boundaries of my yard? I am desperate I have tried everything. I certainly do not need another day in court for failure to confine my dog. Please help.