US 7,445,942 B2
Process for manufacturing segmented MRAM array with patterned segmented magnetic shields
Yimin Guo, San Jose, Calif. (US); and Po-Kang Wang, San Jose, Calif. (US)
Assigned to MagIC Technologies, Inc., Milpitas, Calif. (US)
Filed on Jul. 15, 2005, as Appl. No. 11/182,255.
Prior Publication US 2007/0012952 A1, Jan. 18, 2007
Int. Cl. H01L 21/00 (2006.01)
U.S. Cl. 438—3  [257/659; 257/E21.665; 365/171] 10 Claims
OG exemplary drawing
 
1. A process for providing effective magnetic shielding for a segmented MRAM array, having a top surface, comprising:
providing, as part of said MRAM array, a number of bit slice segments each of which contains a number of bit lines;
further providing, as part of said MRAM array, a number of word lines, each such word line being independently addressable whereby it can interact with one and only one of said bit slice segments at any given time;
depositing a first dielectric layer on said array top surface;
then depositing a layer of soft magnetic material on said first dielectric layer;
patterning said soft magnetic layer to form a plurality of segmented shields each of which fully covers and overlaps one of said bit slice segments, said segmented shields being spaced a distance apart from one another;
providing each segmented shield with two ends and depositing at each of said ends a biasing pad of magnetic material capable of applying a longitudinal magnetic bias, said biasing pad overlapping its associated segmented shield without overlapping any part of its associated bit slice segment;
then depositing a second dielectric layer to fully cover all exposed surfaces;
by means of a magnetic anneal, establishing said longitudinal bias, whereby each segmented shield becomes a single magnetic domain; and
depositing a master magnetic shield layer over said second dielectric layer.