Process for producing magnetoresistive transducers

• US 5,961,848 A
• Filed: 07/10/1996
• Issued: 10/05/1999
• Est. Priority Date: 11/10/1994
• Status: Expired due to Fees

• Current Assignee: Thomson-CSF (Thales SA)
• Original Assignee: Thomson-CSF (Thales SA)
• Inventors: Valet, Thierry, Jacquet, Jean-Claude
• Primary Examiner(s): Brenemar, R. Bruce
• Assistant Examiner(s): Ahmed, Shamim
• Application Number:
  US08/669,376
• Time in Patent Office: 1,182 Days
• Field of Search: 216/2, 216/22, 29/603.01, 360/113
• US Class Current: 216/22
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G11B 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• CPC Class Codes: G11B 5/3173 Batch fabrication, i.e. producing a plurality of head structures in one batch
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: Y10T 29/49021 Magnetic recording reproducing transducer [e.g., tape head, core, etc.]

Abstract

A process for producing magnetoresistive transducers, using microlithographic techniques, where the transducers have magnetic metallic multilayers deposited by sputtering or by molecular beam epitaxy, and forming columns whose side walls will be covered with an insulation and whose tops will be free of this insulation, such that a current is able to flow in the magnetoresistive transducers perpendicular to the plane of the layers so as to exploit a phenomenon of perpendicular giant magnetoresistance. This process includes a step of producing, on one surface of a substrate, a stack including a first conductive layer in contact with a substrate and successive magnetic layers and non-magnetic metallic layers constituting a magnetic metallic multilayer in contact with the conductive layer. The process also includes steps of producing a second conductive layer on the magnetic metallic multilayer, producing a first resin mask having the dimensions of a magnetoresistive sensitive element to be produced and etching, around the mask, the second conductive layer and the magnetic metallic multilayer. Subsequently, the process includes steps of depositing an insulation layer removing the resin mask with the insulation layer lying on the resin mask, and forming an electrical contact on the second conductive layer.

Claims

1. A process for producing a magnetoresistive transducer, comprising the steps of:

stacking a magnetic metallic multilayer component on a first conductive layer to form a stack of layers and stacking said stack of layers on a substrate such that said first conductive layer contacts said substrate, said magnetic metallic multilayer component comprising alternating magnetic and non-magnetic metallic layers;

disposing a second conductive layer on the magnetic metallic multilayer component;

disposing a resin mask, having a dimension consistent with a magnetoresistive sensitive element to be produced as a feature of said magnetoresistive transducer, on a portion of said second conductive layer;

etching said second conductive layer and said magnetic metallic multilayer not covered by the resin mask so as to form respective exposed portions of said second conductive layer, said magnetic metallic multilayer component and said first conductive layer;

depositing, after performing said etching step, an insulation layer on the resin mask, and said respective exposed portions of said second conductive layer, magnetic metallic multilayer component and first conductive layer; and

removing the resin mask and a portion of the insulation layer that covers the resin mask so as to form an electrical contact portion on said second conductive layer.

2. The process according to claim 1, wherein said etching step, comprises etching the magnetic metallic multilayer component in a polygonal shape.

3. The process according to claim 1, wherein said stacking step comprises using in the magnetic metallic multilayer component magnetic layers and non-magnetic layers having respective layer thicknesses of an inclusive range between 0.1 μ

m and 3 μ

m.

4. The process according to claim 1, wherein:

said disposing a resin mask step comprises producing the resin mask as a first resin mask having a first elongated portion; and

further comprising performing additional steps after the removing step, said additional steps including,

disposing a second resin mask on said electrical contact portion of said second conductive layer,

etching said electrical contact portion of said second conductive layer and the magnetic metallic multilayer component in areas not covered by the second resin mask,

depositing another insulation layer, and

removing the second resin mask and a portion of the another insulation layer that covers the second resin mask, wherein said second resin mask has a second elongated portion that is substantially perpendicular to a position of the first elongated portion.

5. The process according to claim 4, wherein respective of said etching steps comprises etching down to the first conductive layer without cutting into the first conductive layer.

6. The process according to claim 4, wherein respective of said etching steps, comprises etching at least part of the first conductive layer.

7. The process according to claim 4, wherein each of said first resin mask and said second resin mask include a large portion adjacent to said first elongated portion and said second elongated portion respectively and being larger in size than said first elongated portion and said second elongated portion, said large portion configured to simplify an execution of respective of said removing steps.

8. The process according to claim 7, wherein respective of said large portions are connected to respective of the first elongated portion and the second elongated portion by respective interconnecting regions having a shape that narrows from said large portion to respective of the first elongated portion and the second elongated portion.

9. The process according to claim 4, wherein said producing step includes producing the first elongated portion to have a length of sufficient size to enable at least two other masks to be positioned substantially perpendicular to the first elongated portion.

10. The process according to claim 1, wherein said etching step comprises etching at most only a fraction of said first conductive layer, so as to allow said first conductive layer to interconnect said transducer element to other transducer elements.

11. The process according to claim 10, further comprising the steps of:

connecting said first conductive layer to another transducer element; and

etching completely said first conductive layer between said transducer element and a third transducer element, so as to decouple said transducer element from said third transducer element.

12. The process according to claim 2, wherein:

said disposing a resin mask step comprises producing the resin mask as a first resin mask having a first elongated portion; and

further comprising performing additional steps after the removing step, said additional steps including,

disposing a second resin mask on said electrical contact portion of said second conductive layer,

etching said electrical contact portion of said second conductive layer and the magnetic metallic multilayer component in areas not covered by the second resin mask,

depositing another insulation layer, and

removing the second resin mask and a portion of the another insulation layer that covers the second resin mask, wherein said second resin mask has a second elongated portion that is substantially perpendicular to a position of the first elongated portion.

13. The process according to claim 3, wherein:

said disposing a resin mask step comprises producing the resin mask as a first resin mask having a first elongated portion; and

further comprising performing additional steps after the removing step, said additional steps including,

disposing a second resin mask on said electrical contact portion of said second conductive layer,

etching said electrical contact portion of said second conductive layer and the magnetic metallic multilayer component in areas not covered by the second resin mask,

depositing another insulation layer, and

removing the second resin mask and a portion of the another insulation layer that covers the second resin mask, wherein said second resin mask has a second elongated portion that is substantially perpendicular to a position of the first elongated portion.

14. The process according to claim 13, wherein respective of said etching steps, comprises etching down to the first conductive layer, without cutting into the first conductive layer.

15. The process according to claim 13, wherein respective of said etching steps, comprises etching at least part of the first conductive layer.

16. The process according to claim 13, wherein each of said first resin mask and said second resin mask include a large portion adjacent to said first elongated portion and said second elongated portion respectively and being larger in size than said first elongated portion and said second elongated portion, said large portion configured to simplify an execution of respective of said removing steps.

17. The process according to claim 16, wherein respective of said large portions are connected to respective of the first elongated portion and the second elongated portion by respective interconnecting regions having a shape that narrows from said large portion to respective of the first elongated portion and the second elongated portion.

18. The process according to claim 12, wherein respective of said etching steps, comprises etching down to the first conductive layer, without cutting into the first conductive layer.

19. The process according to claim 12, wherein respective of said etching steps comprises etching at least part of the first conductive layer.

20. The process according to claim 12, wherein each of said first resin mask and said second resin mask include a large portion adjacent to said first elongated portion and said second elongated portion respectively and being larger in size than said first elongated portion and said second elongated portion, said large portion configured to simplify an execution of respective of said removing steps.