Do they use the cell line of an aborted fetux to make chicken pox vaccine?

No: This is an old rumour, but not entirely correct. It is true that some of the early vaccines (mainly rubella) were developed using human tissue derived from a fetus not purposefully aborted for this reason at all. This occurred 30-35 years ago. The important point is that the vaccines have saved millions of lives, prevented serious infections and disability, and kept our children healthy.