Double-mask near-field transducer (NFT) and method thereof
A double mask process may be used to define layers of a near field transducer (NFT) to enable independent control over each layer. Controlling critical features of the NFT, including the apex width, taper angles, and flare angles is important for achieving desired areal density capabilities (ADC) of heat-assisted magnetic recording (HAMR) devices. By using a first mask to define a first layer of the NFT then a second mask to define a second layer of the NFT, limitations of the single mask NFT definition process may be overcome. For example, the limitation of using the same flare shape for both the first and the second NFT layers. Further, since the apex width of the NFT is defined by a separate mask, further scaling down of the apex width may also be achieved in a double mask NFT definition process.
1 . A magnetic recording head, comprising:
a main pole;
a waveguide disposed adjacent to the main pole; and
a near field transducer (NFT) coupled between the main pole and the waveguide at a media facing surface (MFS), wherein the NFT comprises:
a first layer comprising a first surface facing the MFS, a second surface, and a third surface opposite the second surface, wherein the second and the third surfaces of the first layer are angled relative to a plane perpendicular to the MFS; and
a second layer disposed over the first surface of the first layer, the second layer comprising a first surface facing the MFS, a second surface, and a third surface opposite the second surface, wherein the second and third surfaces of the second layer are angled relative to the plane perpendicular to the MFS, and wherein the angle of the second and third surfaces of the first layer relative to the plane perpendicular to the MFS and the angle of the second and third surfaces of the second layer relative to the plane perpendicular to the MFS are less than 90 degrees and are different from each other.
2 . The magnetic recording head of claim 1 , wherein the angle of the second and third surfaces of the first layer is greater than the angle of the second and third surfaces of the second layer.
3 . The magnetic recording head of claim 1 , wherein the angle of the second and third surfaces of the first layer is less than 45 degrees and the angle of the second and third surfaces of the second layer is 0 degrees.
4 . The magnetic recording head of claim 1 , wherein the angle of the second and third surfaces of the first layer is less than 45 degrees and the angle of the second and third surfaces of the second layer is greater than about 0 degrees.
5 . The magnetic recording head of claim 1 , wherein a height of the first layer is between 50 nanometers (nm) to 70 nm.
6 . The magnetic recording head of claim 5 , wherein a height of the second layer is between 70 nm to 100 nm.
7 . The magnetic recording head of claim 1 , wherein a width of the second layer along the MFS is between 10 nanometers (nm) to 50 nm.
8 . The magnetic recording head of claim 1 , wherein a flare angle of the first layer is less than 65 degrees, and wherein a flare angle of second layer is less than 65 degrees.
9 . The magnetic recording head of claim 1 , wherein a flare angle of the first layer is less than a flare angle of the second layer.
10 . The magnetic recording head of claim 9 , wherein the flare angle of the first layer is 45 degrees, and the flare angle of the second layer is 55 degrees.
11 . A magnetic recording drive comprising the magnetic recording head of claim 1 .
12 . A magnetic recording head, comprising:
a main pole;
a waveguide disposed adjacent to the main pole; and
a near field transducer (NFT) coupled between the main pole and the waveguide at a media facing surface (MFS), wherein the NFT comprises:
a first layer comprising a first surface facing the MFS, a second surface, and a third surface opposite the second surface, wherein the second and the third surfaces of the first layer are angled less than 90 degrees relative to a plane perpendicular to the MFS; and
a second layer disposed over a first surface of the first layer, the second layer comprising a first surface facing the MFS, a second surface, and a third surface opposite the second surface, wherein:
the second and third surfaces of the second layer are angled relative to a plane perpendicular to the MFS;
the angle of the second and third surfaces of the first layer relative to the plane perpendicular to the MFS is greater than the angle of the second and third surfaces of the second layer relative to the plane perpendicular to the MFS; and
a flare angle of the first layer is less than a flare angle of the second layer.
13 . The magnetic recording head of claim 12 , wherein the angle of the second and third surfaces of the first layer is less than 45 degrees and the angle of the second and third surfaces of the second layer is less than 30 degrees.
14 . The magnetic recording head of claim 12 , wherein a width of the first surface of the second layer along the MFS is between 10 nm to 50 nm.
15 . The magnetic recording head of claim 12 , wherein the flare angle of the first layer is less than 65 degrees, and wherein the flare angle of second layer is less than 65 degrees.
16 . A magnetic recording drive comprising the magnetic recording head of claim 12 .
17 . A method of defining a near field transducer (NFT) of a magnetic recording head, the method comprising:
disposing a first mask onto a first surface of a first NFT layer, wherein the first surface is a media facing surface (MFS) of the first NFT layer;
etching or milling a second surface and a third surface of the first NFT layer using the first mask, wherein the second surface is opposite the third surface of the first NFT layer;
removing the first mask;
disposing a second NFT layer over the first surface of the first NFT layer, wherein the second NFT layer comprises a first surface facing the MFS, a second surface, and a third surface opposite the second surface of the second NFT layer;
disposing a second mask over the first surface of the second NFT layer;
etching or milling the second and third surfaces of the second NFT layer using the second mask; and
removing the second mask.
18 . The method of claim 17 , wherein:
the etching or milling of the first NFT layer comprises angling the second and third surfaces of the first NFT layer to a first angle less than 90 degrees relative to a plane perpendicular to the MFS;
the etching or milling of the second NFT layer comprises angling the second and third surfaces of the second NFT layer to a second angle less than 90 degrees relative to the plane perpendicular to the MFS; and
the first angle is greater than the second angle.
19 . The method of claim 17 , wherein:
the etching or milling of the first NFT layer comprises angling the second and third surfaces of the first NFT layer to an angle less than 45 degrees relative to a plane perpendicular to the MFS; and
the etching or milling of the second NFT layer comprises angling the second and third surfaces of the second NFT layer to an angle less than 30 degrees relative to a plane perpendicular to the MFS.
20 . The method of claim 17 , wherein a flare angle of the first NFT layer is less than a flare angle of the second NFT layer.
21 . A magnetic recording drive comprising the magnetic recording head formed by the method of claim 17 .