Magnetic Random Access Memory (MRAM) Manufacturing Process for a Small Magnetic Tunnel Junction (MTJ) Design with a Low Programming Current Requirement
First Claim
1. A method of making a magnetic random access memory cell comprising:
- a. forming a magnetic tunnel junction (MTJ) on top of a wafer;
b. depositing oxide on top of the MTJ;
c. depositing a photo-resist layer on top of the oxide layer;
d. forming a trench in the photo-resist layer and oxide layer, the trench having a width that is substantially the same as that of the MTJ;
e. removing the photo-resist layer;
f. depositing a hard mask layer on top of the oxide layer in the trench;
g. planarizing the wafer to remove the portion of the hard mask layer that is not in the trench, and to substantially level the top of oxide layer and the hard layer on the wafer; and
h. etching the remaining oxide layer; and
i. etching the MTJ to remove the portion of the MTJ which is not covered by the hard mask layer.
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Abstract
A method of making a magnetic random access memory cell includes forming a magnetic tunnel junction (MTJ) on top of a wafer, depositing oxide on top of the MTJ, depositing a photo-resist layer on top of the oxide layer, forming a trench in the photo-resist layer and oxide layer where the trench has a width that is substantially the same as that of the MTJ. Then, the photo-resist layer is removed and a hard mask layer is deposited on top of the oxide layer in the trench and the wafer is planarized to remove the portion of the hard mask layer that is not in the trench to substantially level the top of oxide layer and the hard layer on the wafer. The remaining oxide layer is etched and the the MTJ is etched to remove the portion of the MTJ which is not covered by the hard mask layer.
174 Citations
19 Claims
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1. A method of making a magnetic random access memory cell comprising:
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a. forming a magnetic tunnel junction (MTJ) on top of a wafer; b. depositing oxide on top of the MTJ; c. depositing a photo-resist layer on top of the oxide layer; d. forming a trench in the photo-resist layer and oxide layer, the trench having a width that is substantially the same as that of the MTJ; e. removing the photo-resist layer; f. depositing a hard mask layer on top of the oxide layer in the trench; g. planarizing the wafer to remove the portion of the hard mask layer that is not in the trench, and to substantially level the top of oxide layer and the hard layer on the wafer; and h. etching the remaining oxide layer; and i. etching the MTJ to remove the portion of the MTJ which is not covered by the hard mask layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A magnetic random access memory cell, comprising:
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a complimentary metal-oxide-semiconductor (CMOS) wafer; a conductive layer formed on top of the CMOS wafer; a magnetic tunnel junction (MTJ) centered on top of the conductive layer; a hard mask layer, formed on top of the MTJ; and a shielding layer, wherein the shielding layer covers the hard mask layer, the sides of the MTJ, and the exposed portion of the conductive layer - View Dependent Claims (18, 19)
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Specification