Highly selective ion beam etch hard mask for sub 60nm MRAM devices
First Claim
1. A method for etching a magnetic tunneling junction (MTJ) structure, the method comprising:
- providing a via connection through a dielectric layer to a bottom electrode;
depositing a MTJ stack on the dielectric layer and the via connection;
depositing a top electrode on the MTJ stack;
depositing a selective hard mask on the top electrode;
depositing a dielectric hard mask on the selective hard mask;
patterning and first etching the dielectric hard mask;
after the first etching, second etching the dielectric and the selective hard masks;
after the second etching, third etching the dielectric hard mask and the selective hard mask and the top electrode, the dielectric hard mask being consumed by the third etching;
after the third etching, trimming the top electrode; and
after the trimming, fourth etching the selective hard mask, the top electrode, and the MTJ stack to form a MTJ device, wherein the fourth etching etches into the dielectric layer surrounding the via connection so that a portion of the dielectric layer lines sidewalls of the via connection, and wherein the fourth etching re-deposits material on sidewalls of the dielectric layer lining the via connection and not on sidewalls of a barrier layer of the MTJ device.
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Accused Products
Abstract
A via connection is provided through a dielectric layer to a bottom electrode. A MTJ stack is deposited on the dielectric layer and via connection. A top electrode is deposited on the MTJ stack. A selective hard mask and then a dielectric hard mask are deposited on the top electrode. The dielectric and selective hard masks are patterned and etched. The dielectric and selective hard masks and the top electrode are etched wherein the dielectric hard mask is removed. The top electrode is trimmed using IBE at an angle of 70 to 90 degrees. The selective hard mask, top electrode, and MTJ stack are etched to form a MTJ device wherein over etching into the dielectric layer surrounding the via connection is performed and re-deposition material is formed on sidewalls of the dielectric layer underlying the MTJ device and not on sidewalls of a barrier layer of the MTJ device.
14 Citations
20 Claims
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1. A method for etching a magnetic tunneling junction (MTJ) structure, the method comprising:
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providing a via connection through a dielectric layer to a bottom electrode; depositing a MTJ stack on the dielectric layer and the via connection; depositing a top electrode on the MTJ stack; depositing a selective hard mask on the top electrode; depositing a dielectric hard mask on the selective hard mask; patterning and first etching the dielectric hard mask; after the first etching, second etching the dielectric and the selective hard masks; after the second etching, third etching the dielectric hard mask and the selective hard mask and the top electrode, the dielectric hard mask being consumed by the third etching; after the third etching, trimming the top electrode; and after the trimming, fourth etching the selective hard mask, the top electrode, and the MTJ stack to form a MTJ device, wherein the fourth etching etches into the dielectric layer surrounding the via connection so that a portion of the dielectric layer lines sidewalls of the via connection, and wherein the fourth etching re-deposits material on sidewalls of the dielectric layer lining the via connection and not on sidewalls of a barrier layer of the MTJ device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for etching a magnetic tunneling junction (MTJ) structure, the method comprising:
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providing a via connection through a dielectric layer to a bottom electrode; depositing a MTJ stack on the dielectric layer and the via connection; depositing a top electrode on the MTJ stack; depositing a selective hard mask on the top electrode; depositing a dielectric hard mask on the selective hard mask; patterning and first etching the dielectric hard mask; thereafter second etching the dielectric and the selective hard masks; thereafter third etching the dielectric and selective hard masks and the top electrode wherein the dielectric hard mask is removed; thereafter first trimming the top electrode using ion beam etching (IBE) at an angle of 70 to 90 degrees with respect to a normal line of a top surface of the top electrode; thereafter fourth etching the selective hard mask, the top electrode, and the MTJ stack wherein over etching is performed wherein a MTJ device is formed and wherein the dielectric layer surrounding the via connection is etched into and wherein re-deposition material is formed on sidewalls of the dielectric layer underlying the MTJ device and not on sidewalls of a barrier layer of the MTJ device; thereafter second trimming using IBE at an angle of 70 to 90 degrees with respect to a normal line of a top surface of the top electrode to remove the re-deposition material; thereafter encapsulating the MTJ device and the top electrode with a dielectric or metal oxide; and thereafter removing any remaining the selective hard mask and exposing a top surface of the top electrode. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification