Under-cut via electrode for sub 60nm etchless MRAM devices by decoupling the via etch process
First Claim
1. A method for fabricating a magnetic tunneling junction (MTJ) structure, the method comprising:
- depositing a first dielectric layer on a bottom electrode;
partially etching through the first dielectric layer using a photoresist pattern to form a first via opening having straight sidewalls;
removing the photoresist pattern and etching all the way through the first dielectric layer to the bottom electrode in the first via opening to form a second via opening, wherein the second via opening has tapered sidewalls;
depositing a metal layer over the first dielectric layer and in the second via opening and thereafter removing the metal layer overlying the first dielectric layer;
removing remaining portions of the first dielectric layer, wherein the metal-filled second via opening forms an electrode plug on the bottom electrode;
depositing MTJ stacks on the electrode plug and on the bottom electrode, wherein the MTJ stacks are discontinuous;
depositing a second dielectric layer over the MTJ stacks;
polishing the second dielectric layer to expose a top surface of the MTJ stack on the electrode plug; and
depositing a top electrode layer on the second dielectric layer and contacting the top surface of the MTJ stack on the electrode plug.
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Accused Products
Abstract
A method for fabricating a magnetic tunneling junction (MTJ) structure is described. A first dielectric layer is deposited on a bottom electrode and partially etched through to form a first via opening having straight sidewalls, then etched all the way through to the bottom electrode to form a second via opening having tapered sidewalls. A metal layer is deposited in the second via opening and planarized to the level of the first dielectric layer. The remaining first dielectric layer is removed leaving an electrode plug on the bottom electrode. MTJ stacks are deposited on the electrode plug and on the bottom electrode wherein the MTJ stacks are discontinuous. A second dielectric layer is deposited over the MTJ stacks and polished to expose a top surface of the MTJ stack on the electrode plug. A top electrode layer is deposited to complete the MTJ structure.
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Citations
20 Claims
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1. A method for fabricating a magnetic tunneling junction (MTJ) structure, the method comprising:
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depositing a first dielectric layer on a bottom electrode; partially etching through the first dielectric layer using a photoresist pattern to form a first via opening having straight sidewalls; removing the photoresist pattern and etching all the way through the first dielectric layer to the bottom electrode in the first via opening to form a second via opening, wherein the second via opening has tapered sidewalls; depositing a metal layer over the first dielectric layer and in the second via opening and thereafter removing the metal layer overlying the first dielectric layer; removing remaining portions of the first dielectric layer, wherein the metal-filled second via opening forms an electrode plug on the bottom electrode; depositing MTJ stacks on the electrode plug and on the bottom electrode, wherein the MTJ stacks are discontinuous; depositing a second dielectric layer over the MTJ stacks; polishing the second dielectric layer to expose a top surface of the MTJ stack on the electrode plug; and depositing a top electrode layer on the second dielectric layer and contacting the top surface of the MTJ stack on the electrode plug. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for fabricating a magnetic tunneling junction (MTJ) structure, the method comprising:
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depositing a first dielectric layer on a bottom electrode; partially etching through the first dielectric layer using a photoresist pattern to form a first via opening having straight sidewalls; thereafter removing the photoresist pattern and etching all the way through the first dielectric layer to the bottom electrode in the first via opening to form a second via opening, wherein the second via opening has tapered sidewalls; depositing a metal layer over the first dielectric layer and in the second via opening and thereafter removing the metal layer overlying the first dielectric layer; removing portions of the first dielectric layer adjacent to the metal in the second via opening, wherein the metal in the second via opening forms an electrode plug on the bottom electrode; thereafter IBE trimming the electrode plug to proportionally decrease a top width and a bottom width of the via electrode to less than or equal to 60 nanometers and a less than or equal to 40 nanometers, respectively; thereafter depositing MTJ stacks on the electrode plug and on the bottom electrode, wherein the MTJ stacks are discontinuous; depositing a second dielectric layer over the MTJ stacks; polishing the second dielectric layer to expose a top surface of the MTJ stack on the electrode plug; and thereafter depositing a top electrode layer on the second dielectric layer and contacting the top surface of the MTJ stack on the electrode plug. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification