Method for making a contact magnetic transfer template
View Patent ↗A contact magnetic transfer (CMT) master template is made by first adhering a plastic film to a first surface of a silicon wafer. A resist pattern is then formed on the polyimide film and the polyimide is reactive-ion-etched through the resist to form recesses. The resist is removed and a chemical-mechanical-polishing (CMP) stop layer is deposited over the non-recessed regions of the polyimide, and optionally into the bottoms of the recesses. A layer of magnetic material is then deposited over the polyimide film to fill the recesses. A CMP process is then performed to remove magnetic material above the recesses and above the non-recessed regions and continued until the CMP stop layer is reached. The resulting upper surface of the polyimide film is then a continuous planar film of magnetic islands and regions of CMP stop layer material that function as the nonmagnetic regions of the template.
1. A method for making a flexible contact magnetic transfer template comprising:
providing a silicon substrate having first and second generally planar surfaces;
adhering a plastic film to the first surface of the substrate;
depositing a chemical-mechanical-polishing (CMP) stop layer on the plastic film;
forming a pattern of resist on the CMP stop layer;
etching the plastic film through the resist pattern to form recesses in the plastic film;
removing the resist;
depositing a layer of magnetic material over the CMP stop layer and into the recesses in the plastic film;
removing the magnetic material by CMP until the CMP stop layer is reached; and
removing the silicon substrate from the plastic film.
2. The method of claim 1 wherein adhering a plastic film comprises coating the first surface of the silicon substrate with liquid polyimide and curing the polyimide.
3. The method of claim 1 wherein forming a pattern of resist on the CMP stop layer comprises depositing a layer of e-beam resist, exposing the e-beam resist layer using an e-beam lithographic tool, and developing the exposed e-beam resist.
4. The method of claim 1 wherein etching the plastic film comprises reactive-ion-etching the plastic film in an oxygen/argon atmosphere.
5. The method of claim 1 wherein depositing a CMP stop layer comprises depositing a layer of material selected from the group consisting of diamond-like carbon (DLC), Ta, one or more nitrides of Ta, one or more nitrides of Ti, Cr and NiCr alloy.
6. The method of claim 1 wherein depositing a layer of magnetic material comprises depositing a layer of an alloy of one or more of Ni, Fe and Co.
7. The method of claim 1 wherein removing the magnetic material by CMP comprises using a KOH or NH 4 OH based CMP slurry with colloidal silica particles having an average particle size of between approximately 20 and 200 nm.
8. The method of claim 1 wherein removing the silicon substrate from the plastic film comprises wet-etching the silicon substrate from its second surface.
9. The method of claim 1 wherein wet-etching the silicon substrate comprises etching with a mixture of HF and HNO 3 .
10. The method of claim 8 further comprising depositing a barrier layer on the first surface of the silicon substrate prior to adhering the plastic film, the barrier layer being formed of a material resistant to the wet etchant.
11. The method of claim 10 wherein the barrier layer is a material selected from the group consisting of Cr and Au.
12. The method of claim 1 further comprising depositing an etch-protect layer on the CMP stop layer prior to forming the pattern of resist.
13. The method of claim 12 wherein the etch-protect layer is a material selected from the group consisting of Ge, Cr, Ta and W.
14. The method of claim 12 further comprising etching the etch-protect layer through the resist pattern to remove the etch-protect layer prior to etching the plastic film.
15. The method of claim 14 wherein the etch-protect layer is Ge and wherein etching the etch-protect layer comprises reactive-ion-etching the Ge in an CHF 3 gas.
16. The method of claim 12 further comprising removing the etch-protect layer from beneath the resist after removing the resist.
17. The method of claim 16 wherein the etch-protect layer is Ge and wherein removing the Ge from beneath the resist comprises removing the Ge with hydrogen peroxide.
18. The method of claim 1 further comprising depositing an etch-protect layer on the CMP stop layer before forming the pattern of resist.
19. The method of claim 18 further comprising etching the etch-protect layer and the CMP stop layer through the resist pattern to remove the etch-protect layer and CMP stop layer prior to etching the plastic film.
20. The method of claim 19 wherein the etch-protect layer is Ge and wherein etching the etch-protect layer comprises reactive-ion-etching the Ge in CHF 3 gas.
21. The method of claim 1 further comprising depositing a protective film over the CMP stop layer after removing the magnetic material by CMP.
22. The method of claim 1 further comprising depositing a perfluorocarbon coating over the protective film.
23. A method for making a flexible contact magnetic transfer template comprising:
providing a silicon substrate having first and second generally planar surfaces;
depositing a barrier layer on the first surface of the silicon substrate, the barrier layer being formed of a material resistant to a wet etchant capable of etching silicon;
adhering a polyimide film to the barrier layer by coating the barrier layer with liquid polyimide and curing the polyimide;
forming a pattern of resist on the polyimide film;
etching the polyimide film through the resist pattern to form recesses in the polyimide film;
removing the resist;
after etching the polyimide film and removing the resist, depositing a chemical-mechanical-polishing (CMP) stop layer on the polyimide film and into the recesses in the polyimide film;
depositing a layer of magnetic material over the CMP stop layer and into the recesses in the polyimide film;
removing the magnetic material by CMP until the CMP stop layer is reached; and
removing the silicon substrate from the polyimide film by wet-etching the silicon substrate from its second surface until substantially all the silicon in contact with the baffier layer has been removed.
24. The method of claim 23 wherein forming a pattern of resist on the polyimide film comprises depositing a layer of e-beam resist, exposing the e-beam resist layer using an e-beam lithographic tool, and developing the exposed e-beam resist.
25. The method of claim 23 wherein etching the polyimide film comprises reactive-ion-etching the polyimide film in an oxygen/argon atmosphere.
26. The method of claim 23 wherein depositing a CMP stop layer comprises depositing a layer of material selected from the group consisting of diamond-like carbon (DLC), Ta, one or more nitrides of Ta, one or more nitrides of Ti, Cr and Ni Cr alloy.
27. The method of claim 23 wherein depositing a layer of magnetic material comprises depositing a layer of an alloy of one or more of Ni, Fe and Co.
28. The method of claim 23 wherein removing the magnetic material by CMP comprises using a KOH or NH 4 OH based CMP slurry with colloidal silica particles having an average particle size of between approximately 20 and 200 nm.
29. The method of claim 23 wherein wet-etching the silicon substrate comprises etching with a mixture of HF and HNO 3 .
30. The method of claim 23 wherein the barrier layer is a material selected from the group consisting of Cr and Au.
31. The method of claim 23 further comprising depositing an etch-protect layer on the polyimide film prior to forming the pattern of resist.
32. The method of claim 31 wherein the etch-protect layer is a material selected from the group consisting of Ge, Ta, Cr and W.
33. The method of claim 31 further comprising etching the etch-protect layer through the resist pattern to remove the etch-protect layer prior to etching the polyimide film.
34. The method of claim 33 wherein the etch-protect layer is Ge and wherein etching the etch-protect layer comprises reactive-ion-etching the Ge in an CHF 3 gas.
35. The method of claim 31 further comprising removing the etch-protect layer from beneath the resist after removing the resist.
36. The method of claim 35 wherein the etch-protect layer is Ge and wherein removing the Ge from beneath the resist comprises removing the Ge with hydrogen peroxide.
37. The method of claim 23 further comprising depositing a protective film over the CMP stop layer after removing the magnetic material by CMP.
38. The method of claim 23 further comprising depositing a perfluorocarbon coating over the protective film.
39. A method for making a flexible contact magnetic transfer template comprising:
providing a silicon substrate having first and second generally planar surfaces;
adhering a plastic film to the first surface of the substrate;
forming a pattern of resist on the plastic film;
etching the plastic film through the resist pattern to form recesses in the plastic film;
removing the resist;
after etching the plastic film and removing the resist, depositing a chemical-mechanical-polishing (CMP) stop layer on the plastic film and into the recesses in the plastic film;
depositing a layer of magnetic material over the CMP stop layer and into the recesses in the plastic film;
removing the magnetic material by CMP until the CMP stop layer is reached; and
removing the silicon substrate from the plastic film.
40. A method for making a flexible contact magnetic transfer template comprising:
providing a silicon substrate having first and second generally planar surfaces;
depositing a barrier layer on the first surface of the silicon substrate, the barrier layer being formed of a material resistant to a wet etchant capable of etching silicon;
adhering a polyimide film to the barrier layer by coating the barrier layer with liquid polyimide and curing the polyimide;
depositing a chemical-mechanical-polishing (CMP) stop layer on the polyimide film;
forming a pattern of resist on the (CMP) stop layer;
etching the polyimide film through the resist pattern to form recesses in the polyimide film;
removing the resist;
depositing a layer of magnetic material over the CMP stop layer and into the recesses in the polyimide film;
removing the magnetic material by CMP until the CMP stop layer is reached; and
removing the silicon substrate from the polyimide film by wet-etching the silicon substrate from its second surface until substantially all the silicon in contact with the baffier layer has been removed.