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US006709942B2
(12) United States Patent ao) Patent No.: us 6,709,942 B2
Pan et al. (45) Date of Patent: Mar. 23,2004
(54) METHOD OF FABRICATING MAGNETIC YOKE STRUCTURES IN MRAM DEVICES
(75) Inventors: Wei Pan, Vancouver, WA (US); Sheng Teng Hsu, Camas, WA (US)
(73) Assignee: Sharp Laboratories of America, Inc.,
Camas, WA (US)
( * ) Notice: Subject to any disclaimer, the term ol this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 10/385,390
(22) Filed: Mar. 10, 2003
(65) Prior Publication Data
US 2003/0168684 Al Sep. 11, 2003
Related U.S. Application Data
(62) Division ol application No. 10/061,974, filed on Jan. 31, 2002, now Pat. No. 6,548,849.
(51) Int. CI.7 H01L 21/20
(52) U.S. CI 438/381; 438/238; 438/3
(58) Field of Search 438/381, 3, 197,
438/238, 680, 681, 692
An MRAM device includes a substrate; plural conductive lines, including a bit line and a word line; and a MTJ stack including a pair ol magnetic yoke structures, wherein each ol said yoke structures surrounds a conductive line. A method ol labricating a magnetic yoke in an MRAM structure includes preparing a substrate; forming a first conductive line on the substrate; labricating a MTJ stack, including labricating a first magnetic yoke structure about the first conductive line; forming a second conductive line on the MTJ stack; labricating a second magnetic yoke about the second conductive line; depositing a layer ol oxide on the structure; and metallizing the structure.
10 Claims, 7 Drawing Sheets
