5 microns and preferably about 0 3 microns just enough to ensure that the via for the bit line mtv is filled an etch back is performed to remove the copper overlying the barrier layer 26 using layer 26 as an etch stop and typically using wet chemistry for example an etch time of about 132 seconds will remove approximately 1450 angstroms of copper finally the seed layer 26 is removed where it is not covered by the copper resulting in fig8 the seed layer may be removed for example by a reactive ion etching rie process after cu etch back and seed removal the bit line will be formed in the present disclosure the bit line is formed of aluminum instead of copper the aluminum thickness should be about three times the thickness of a copper bit line in order to have the same resistivity performance for example the aluminum layer is deposited to a thickness of between about 4000 and 8000 angstroms the aluminum layer is etched to form bit line 30 contacting the mtj 20 array and the mtv connections 30 as illustrated in fig9 a key feature of the present disclosure is to first use a lithography and etching process to provide an opening to the cmos devices next deposit a seed layer plate copper into the opening and etch back to form the connection between the cmos metal layer and the bit line and finally to form the bit line by deposition and etching the bit line contacts the mtj elements and the connections to the cmos metal etching to form the opening to the cmos metal layer cannot be guaranteed to proceed completely to the metal layer due.