Magnetic storage device

• US 8,492,881 B2
• Filed: 03/22/2010
• Issued: 07/23/2013
• Est. Priority Date: 04/01/2009
• Status: Expired due to Fees

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Electronics Corporation
• Inventors: Kuroiwa, Takeharu, Tarutani, Masayoshi, Takenaga, Takashi, Takada, Hiroshi
• Primary Examiner(s): BERNSTEIN, ALLISON
• Application Number:
  US12/728,885
• Publication Number:
  US 20100254182A1
• Time in Patent Office: 1,219 Days
• Field of Search: 365/158, 365/171, 257/421, 257/422, 257/677, 257/659, 257/E23.114
• US Class Current: 257/659
• CPC Class Codes: G11C 11/1659 Cell access
• CPC Class Codes: G11C 11/1673 Reading or sensing circuits or methods
• CPC Class Codes: G11C 11/1675 Writing or programming circuits or methods
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 23/3107 the device being completely enclosed
• CPC Class Codes: H01L 23/49579 characterised by the materials of the lead frames or layers thereon
• CPC Class Codes: H01L 27/105 including field-effect components
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/30107 Inductance
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding
• CPC Class Codes: H10B 61/22 of the field-effect transistor [FET] type
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

A magnetic storage device which enables stable operation at the time of recording information into MRAM and the stable retention of recorded information. The die of the magnetic storage device has a substrate, first and second wirings, a magnetic storage element and a first magnetic shielding structure. The first magnetic shielding structure is formed to cover the magnetic storage element in a plan view. Second and third magnetic shielding structures sandwich the die in a thickness direction. A lead frame member has the die mounted thereon and contains a ferromagnetic material. The lead frame member overlaps with only part of the die in a plan view.

Claims

1. A magnetic storage device comprising:

a die including;

a substrate;

a first wiring which is formed over the substrate and has a part extending in one direction;

a second wiring which is formed over the substrate, intersects the first wiring in a plan view and is separate from the first wiring in the thickness direction of the substrate;

a magnetic storage element at least part of which is sandwiched between the first and second wirings in a region where the first and second wirings intersect each other with a space therebetween; and

a first magnetic shielding structure which is formed to cover the magnetic storage element in a plan view;

second and third magnetic shielding structures which sandwich the die in the thickness direction; and

a lead frame member which has the die mounted thereon, and contains a ferromagnetic material,

wherein the lead frame member overlaps with only part of the die in a plan view.

2. The magnetic storage device according to claim 1, wherein one of the second and third shielding structures is larger in size than the die, and the other is smaller in size than the die.

3. The magnetic storage device according to claim 2, wherein the other magnetic shielding structure covers all the memory cell region of the die in a plan view.

4. The magnetic storage device according to claim 2, wherein the second and third magnetic shielding structures cover all the memory cell region of the die, and the distances between the ends of the second and third shielding structures and the end of the memory cell region are least 0.3 mm.

5. The magnetic storage device according to claim 1, wherein a part overlapping with the die in a plan view of the lead frame member is made of a material having a high saturation magnetic flux density of 1.2 tesla or more, and the second and third magnetic shielding structures are made of a material having a high relative magnetic permeability of 5,000 or more.

6. The magnetic storage device according to claim 1, wherein at least one of the second and third magnetic shielding structures has a planar shape with long sides and short sides, and the ratio of the long side and the short side is 3 or less.

7. The magnetic storage device according to claim 1, wherein at least one of the second and third magnetic shielding structures is in contact with a mold structure and has a cyclic uneven structure on the contact surface with the mold structure.

8. The magnetic storage device according to claim 7, wherein the uneven structure has a dot-like, rectangular or groove-like shape.

9. The magnetic storage device according to claim 1, wherein the second and third magnetic shielding structures are each coupled to the die by an adhesive layer.

10. The magnetic storage device according to claim 9, wherein the adhesive layer contains a ferromagnetic material.

11. The magnetic storage device according to claim 1, wherein at least one of the second and third magnetic shielding structures has projection portions projecting in a direction away from the die at the ends in a plan view.

12. The magnetic storage device according to claim 1, wherein the interval between the second and third shielding structures is 0.15 to 0.5 mm.

13. The magnetic storage device according to claim 1, wherein the interval between at least one of the first and second wirings and the first magnetic shielding structure is 100 nm or less.

14. The magnetic storage device according to claim 1, wherein the first magnetic shielding structure is divided into a plurality of parts which extend in the extension direction of any one of the first and second wirings.

15. The magnetic storage device according to claim 1,

wherein the magnetic storage element comprises:

a fixed layer whose magnetization direction is fixed; and

a recording layer having a magnetization easy axis, and

wherein information is recorded by controlling the magnetization direction of the recording layer with a magnetic field produced by applying a predetermined current to the first and second wirings, and is read by a magnetoresistive effect.

16. The magnetic storage device according to claim 1,

wherein the magnetic storage element comprises:

a fixed layer whose magnetization direction is fixed; and

a recording layer having a magnetization easy axis, and

wherein information is recorded by controlling the magnetization direction of the recording layer with torque produced by applying a spin polarized current to the recording layer, and is read by a magnetoresistive effect.