Fabrication process for a magnetic tunnel junction device
First Claim
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1. A method of fabricating a magnetic tunnel junction (MTJ) device, comprising:
- oxidizing a patterned hard mask to form a surface oxide thereon; and
etching an MTJ stack in alignment with the patterned hard mask after the oxidizing of the patterned hard mask.
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Abstract
A method of fabricating a magnetic tunnel junction (MTJ) device is provided. A patterned hard mask is oxidized to form a surface oxide thereon. An MTJ stack is etched in alignment with the patterned hard mask after the oxidizing of the patterned hard mask. Preferably, the MTJ stack etch recipe includes chlorine and oxygen. Etch selectivity between the hard mask and the MTJ stack is improved.
158 Citations
58 Claims
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1. A method of fabricating a magnetic tunnel junction (MTJ) device, comprising:
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oxidizing a patterned hard mask to form a surface oxide thereon; and
etching an MTJ stack in alignment with the patterned hard mask after the oxidizing of the patterned hard mask. - View Dependent Claims (2, 3, 4, 5)
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6. A magnetic tunnel junction (MTJ) device, comprising:
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an MTJ stack;
a tantalum nitride layer over the MTJ stack;
a titanium layer over the tantalum nitride layer; and
a titanium nitride layer over the titanium layer.
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7. A magnetic tunnel junction (MTJ) device, comprising:
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an MTJ stack;
a titanium layer over the MTJ stack; and
a titanium nitride layer over the titanium layer. - View Dependent Claims (8)
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9. A method of fabricating a magnetic tunnel junction (MTJ) device, comprising:
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providing a hard mask over an MTJ stack;
providing a patterned photoresist layer over the hard mask;
etching through a first thickness of the hard mask, the first thickness being less than an entire thickness for the hard mask;
removing the photoresist layer after etching through the first thickness of the hard mask; and
etching through a remaining thickness of the hard mask after removing the photoresist layer. - View Dependent Claims (10, 11)
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12. A method of fabricating a magnetic tunnel junction (MTJ) device, comprising:
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providing a hard mask over an MTJ stack, the hard mask comprising a titanium nitride layer over a titanium layer;
providing a patterned photoresist layer over the hard mask;
etching through a majority of the titanium nitride layer with a first etch recipe;
etching through a remainder of the titanium nitride layer and a first portion of the titanium layer with a second etch recipe; and
removing the photoresist layer. - View Dependent Claims (13)
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14. A method of fabricating a magnetic tunnel junction (MTJ) device, comprising:
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providing an initial structure comprising;
an underlying layer;
a bottom tantalum nitride layer over the underlying layer, a tantalum layer over the bottom tantalum nitride layer, an MTJ stack over the tantalum layer, a tantalum nitride cap layer over the MTJ stack, a titanium layer over the tantalum nitride cap layer, a titanium nitride layer over the titanium layer, and a patterned photoresist layer over the titanium nitride layer;
etching through a majority of the titanium nitride layer with a first etch recipe;
etching through a remainder of the titanium nitride layer and a first portion of the titanium layer with a second etch recipe;
removing the photoresist layer;
etching through a remainder of the titanium layer and at least a majority of the tantalum nitride cap layer with a third etch recipe;
oxidizing the titanium nitride layer, the titanium layer, and the tantalum nitride cap layer to form a surface oxide thereon;
etching the MTJ stack with a fourth etch recipe; and
etching the tantalum layer and the bottom tantalum nitride layer with a fifth etch recipe. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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43. A method of fabricating a magnetic tunnel junction (MTJ) device, comprising:
etching an MTJ stack using an MTJ etch chemistry at a total flow rate, and the total flow rate of the MTJ etch chemistry comprising a chlorine flow rate, an oxygen flow rate, and an argon flow rate, wherein the chlorine flow rate is about 20-60% of the total flow rate, the oxygen flow rate is about 10-40% of the total flow rate, and the argon flow rate is about 20-35% of the total flow rate. - View Dependent Claims (44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
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54. A method of fabricating a magnetic tunnel junction (MTJ) device, comprising:
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providing a stack of initial layers over an underlying layer, wherein the stack of initial layers comprises a photoresist layer, a hard mask, an MTJ stack, the photoresist being over the hard mask, and the hard mask being over the MTJ stack;
etching the hard mask to form a hard-mask pattern therein in alignment with a resist pattern formed in the photoresist layer;
stripping the photoresist layer using a resist-strip plasma comprising oxygen;
oxidizing exposed surfaces of the hard mask during the stripping of the photoresist layer; and
etching the MTJ stack in alignment with the hard-mask pattern, the etching of the MTJ stack being performed using an MTJ etch chemistry at a total flow rate, and the total flow rate of the MTJ etch chemistry comprising a chlorine flow rate, an oxygen flow rate, and an argon flow rate, wherein the chlorine flow rate is about 20-60% of the total flow rate, the oxygen flow rate is about 10-40% of the total flow rate, and the argon flow rate is about 20-35% of the total flow rate. - View Dependent Claims (55, 56, 57, 58)
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Specification