Moving bedtime

My 3 month old goes to bed around 10:30pm ever night. His last nap usually ends around 730pm. We've tried to make that his bedtime but he is up after 45 minutes. Then he won't sleep until 10:30 although he is clearly tired. He also wakes up pretty late (930am), but that will change in two weeks when k go back to work. Any ideas on how to move his bedtime up? I've been able to move it a few minutes each night, but if I move it by 15-30 minutes, he just screams when I put him down.