You can help their ears go up easier, by first clipping the hair off the ears and trim them along the edges. Then if that doesn't work - yes - you can tape them. It helps them to know what they are suppose to do. You can find many sites on the web on how to do this - one such site is owned by Rhapsody:
http://www.yorkie.org/dogs/grooming_yorkies.html
Best of luck with your baby. He is a cutie!
T.