Patent Application
20130004736
Patterned media fabrication processes leave magnetic islands exposed to air and direct contact with backfill materials. The exposure to air and direct contact with backfill materials extends from the top of the magnetic islands to the sidewall surfaces. The exposure may cause chemical reactions that cause physical damage to the magnetic dots and magnetic properties degradation. Backfill materials may cause surface diffusion on the magnetic dot surface that can develop into extraneous metal lattice structures that can change the magnetic properties.
In a following description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration a specific example in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. In a following description, the term magnetic island refers to the top and sidewalls of the higher relief non-etched portions of the patterned magnetic materials of a patterned stack. In a following description, the term magnetic film refers to the lower relief etched surfaces of the patterned magnetic materials of a patterned stack.
It should be noted that the descriptions that follow, for example, in terms of method of magnetic island protection with sidewall deposition for bit patterned media fabrication is described for illustrative purposes and the underlying system can apply to any number and multiple types patterned stacks and planarization processes. In one embodiment of the present invention, the magnetic dots protection can be configured as a continuous film layer. In other embodiments the continuous film layer includes materials be inert to magnetic island materials and configured to prevent changes in magnetic properties using the present invention.
The first step in the method of protecting patterned magnetic materials of a stack is depositing a thin continuous film over magnetic islands and films 110. The deposition of the thin continuous film may include materials that are inert to the magnetic materials of the patterned stack 100. The thin continuous film deposition of inert materials is used in forming a thin interim interface layer 120 of one embodiment. The thin interim interface layer 120 is used for creating protection 125 of the magnetic islands and films 130 from damage. Damage to the magnetic islands and films may include air exposure damage 140 such as oxidized Interface surfaces.
The thin interim interface layer 120 insulates the magnetic materials shortly after patterning from being exposed to air and to prevent magnetic properties degradation and physical deterioration. The thin interim interface layer 120 also provides an interface on the side wall surfaces and tops of the magnetic islands and the etched surfaces of the magnetic films of one embodiment.
The interface prevents damage from contact with backfilled materials 150 that may cause a chemical reaction between the backfilled materials and the magnetic materials. The chemical reactions may lead to development of metal lattices which will interfere and alter the magnetic properties of the patterned magnetic structures. Backfilling of the patterned surfaces with materials may include planarization processes to create a smooth surface of the patterned stack topography. The magnetic islands may incur damage from planarization processes 160 such as etch back of the backfilled materials. The method of protecting patterned magnetic materials of a stack provides protection of the patterned magnetic materials over a broad range of material combinations and thereby maintains the intended magnetic properties of the patterned stack of one embodiment.
A step in the method of protecting patterned magnetic materials of a stack may include the depositing a thin continuous film over magnetic islands and films 110. The magnetic islands and films are created by the patterning processes. In one embodiment the deposition of the thin continuous film may be performed in the vacuum environment subsequent to the patterning process. The deposition of the thin continuous film includes using film materials inert to the magnetic materials 200 of the stack. The thin continuous film deposition is used in forming a thin interim interface layer 120 of one embodiment.
The inert film materials in one embodiment is configured to prevent changes in magnetic properties 210 of the magnetic structures of the stack. The inert materials of the thin interim interface layer 120 provide an interface that is configured to prevent a chemical reaction 220 between the magnetic materials and surrounding materials such as those used for backfilling the patterned topography. The thin interim interface layer 120 is configured to prevent diffusion of the magnetic materials 230 of one embodiment.
The depositing of a thin continuous film over magnetic islands and films 110 will cover the magnetic island tops and sidewalls 240 surfaces with the thin interim interface layer 120. The forming of a thin interim interface layer 120 will also deposit inert materials on magnetic film etched surfaces 250. The thin interim interface layer 120 is used for protecting the magnetic islands and films 130 from damage during following fabrication process and beyond. When the patterned stack 100 leaves the vacuum environment the magnetic islands and films 130 may be exposed to air. Air that includes oxygen may react with the magnetic materials and cause air exposure damage 140 of one embodiment.
Following the patterning process the stack topography may be backfilled to create a smooth surface. Forming a thin interim interface layer 120 coats the surfaces of the magnetic islands and magnetic films preventing physical contact with the backfilled materials. The interface coating provided by the inert materials of the thin interim interface layer protects the patterned stack against damage from contact with backfilled materials 150. Contact with the materials used for backfilling may chemically react with the magnetic materials. The contact chemical reaction may cause deterioration of the magnetic materials leading to malfunctions created by changes in the magnetic properties and volume of the patterned magnetic islands. The contact chemical reaction may cause development of metal lattices which could alter the magnetic properties in inconstant ways that would lead to permanent damage in the magnetic islands performance of one embodiment.
The process of backfilling of the stack topography may include planarization processes. The planarization processes are used to reduce height differences on the surface and create a smooth surface on the patterned stack. A finish coating such as a carbon over coat (COC) and lubrication may be deposited upon smooth surface after planarization. Planarization processes may include an etch-back process to chemically remove the remaining mask layer and portions of the backfilled materials. Damage to unprotected magnetic islands may occur including for example chemical reactions with the chemicals used in an etch-back process. Forming a thin interim interface layer 120 that coats the surfaces of the magnetic islands, including the tops and sidewall surfaces, prevents damage from planarization processes 160 such as etch back of one embodiment.
The method of protecting patterned magnetic materials of a stack prevents deterioration and damage to both the magnetic islands and magnetic films of a patterned stack. Damage from exposure to air, contact with backfill materials and planarization processes is prevented by the thin interim interface layer. The protection against damage preserves the physical features and magnetic properties of the magnetic materials of a patterned stack. The thin interim interface layer damage protection thereby increases the quality of patterned stacks such as bit-patterned media of one embodiment.
After formation of carbon mask pattern, the magnetic etch processes such as IBE remove the unprotected magnetic materials to a predetermined depth. The magnetic materials remaining under each hardened carbon mask creates a magnetic island 310. The magnetic island 310 appears as a high relief feature on the patterned stack topography with residual etched carbon 330 on top. The areas where the patterning processes have removed magnetic material form etched magnetic film 320 which create a surface below the tops of the magnetic island 310 of one embodiment.
The thin interim interface layer 360 can be seen up to the top of the etched magnetic film 320 of
The deposition of the thin continuous film may include using a material that is inert to the magnetic materials of a patterned stack. The inert materials may include for example carbon that may be deposited in a thickness of two nm. The inert material is configured to prevent diffusion of the magnetic materials of a patterned stack. The thin interim interface layer will insulate magnetic island from their surroundings including air and backfilled materials. The thin interim interface layer includes application to patterned stack fabrication that includes planarization processes. The thin interim interface layer provides protection against damage in a patterned stack fabrication that may include planarization processes of one embodiment.
The backfilled material 340 may be deposited above the heights of each magnetic island 310 and residual etched carbon 330. In one embodiment the patterned stack fabrication process may not include planarization processes. Not including planarization processes would leave the thin interim interface layer 360 intact and provide the protection of the magnetic materials of the patterned stack magnetic layer 300. In another embodiment the patterned stack fabrication process may include planarization processes.
The surface of planarization 380 may leave planarized backfill material 420 below the tops of each magnetic island 310 of
The foregoing has described the principles, embodiments and modes of operation. However, the invention should not be construed as being limited to the particular embodiments discussed. The above described embodiments should be regarded as illustrative rather than restrictive, and it should be appreciated that variations may be made in those embodiments by workers skilled in the art without departing from the scope as defined by the following claims.
