Pattern transfer with self-similar sacrificial mask layer and vector magnetic field sensor
View Patent ↗A method is provided for producing a lithographic pattern using a mask that includes the same materials as the material to be etched, allowing the pattern to be transferred and the etch mask to be removed in one step. In accordance with features of the invention, the method includes building up of a layer or layers of material of specific thickness on top of a substrate so that temporal control of an etching process allows formation of the desired pattern. Different exchange bias directions can be established by the use of shape anisotropy for the exchange biased component of a spin valve device. This enables several different magnetic reference directions to be present on a single chip, which allows a more compact magnetic field sensor to be developed. In accordance with features of the invention, different field directions are established on one single chip by using shape anisotropy.
1. A method for producing a lithographic pattern comprising the steps of:
using a mask, said mask including a plurality of materials, each said material corresponding to an identical material of a structure to be etched,
depositing said mask onto said structure to be etched including depositing each said identical material onto said structure to be etched to define a multilayer mask having multiple layers corresponding to said structure to be etched; and
transferring the pattern and removing said multilayer mask from said structure being etched in one etch multilayer step; said one etch multilayer step implemented independently of etch selectivity characteristics of said structure and said multilayer mask; said one etch multilayer step including identical etch rates for each said corresponding identical material of said structure and mask layer.
2. A method for producing a lithographic pattern as recited in claim 1 includes providing an initial structure of said structure to be etched.
3. A method for producing a lithographic pattern as recited in claim 2 wherein providing said initial structure includes depositing a plurality of materials onto a substrate to provide a selected material thickness for each deposited layer for defining said initial structure.
4. A method for producing a lithographic pattern as recited in claim 3 wherein said multilayer mask includes said identical material having an identical material thickness of said corresponding deposited layer of said initial structure to be etched.
5. A method for producing a lithographic pattern as recited in claim 1 wherein depositing said mask onto said initial structure includes the step of using e-beam lithography for defining lines on said initial structure.
6. A method for producing a lithographic pattern as recited in claim 1 wherein the step of transferring the pattern and removing said mask in one etch multilayer step includes ion-milling said structure and said multilayer mask.
7. A method for producing a lithographic pattern as recited in claim 1 wherein transferring the pattern and removing said multilayer mask includes providing temporal control of an etching process for forming of a desired pattern.
8. A method for producing a lithographic pattern as recited in claim 1 wherein said structure to be etched is a spin valve device and includes the steps of establishing different exchange bias directions by the use of shape anisotropy for an exchange biased component of said spin valve device, eliminating the use of multiple annealing steps.