Tester for testing magnetic memory
View Patent ↗According to one embodiment, a tester includes a magnetic shield portion having a space which is shielded from an external magnetic field, a controller generating a test signal for testing a magnetic memory having a magnetoresistive element provided in the space, an interface portion in the space, the interface portion which functions as an interface between the controller and the magnetic memory, and a magnetic field generating portion in the space, the magnetic field generating portion generating a test magnetic field while the magnetic memory is tested by the test signal.
1. A tester comprising:
a controller which generates a test signal for testing a magnetic memory having a magnetoresistive element;
an interface portion which functions as an interface between the controller and the magnetic memory; and
a magnetic field generating portion which applies a test magnetic field to the magnetoresistive element,
wherein the controller is configured to:
execute a first step in which a first data is written to the magnetoresistive element;
execute a second step in which the test magnetic field is applied to the magnetoresistive element for a fixed period of time, after executing the first step;
execute a third step in which a second data is read from the magnetoresistive element, after executing the second step; and
execute a fourth step in which a characteristic of the magnetoresistive element is evaluated by comparing the first and second data, after executing the third step.
2. The tester of claim 1 , wherein the test magnetic field is directed in a direction of θ to a magnetization direction of the magnetoresistive element, where 0°≦θ≦90°.
3. The tester of claim 1 , wherein the test magnetic field has an intensity lower than an intensity of a reversal magnetic field which is reversed to a magnetization direction of a storage layer of the magnetoresistive element.
4. The tester of claim 1 , wherein the magnetoresistive element is provided on a semiconductor substrate, and has a magnetization direction which is perpendicular to a surface of the semiconductor substrate.
5. The tester of claim 1 , wherein the magnetic field generating portion comprises a permanent magnet or an electromagnet controlled by the controller.
6. The tester of claim 1 , wherein the interface portion includes a probe which contacts with an electrode of the magnetic memory while the magnetic memory is tested by the test signal, and a holder having a first surface and a second surface, the holder holding the probe in the first surface.
7. The tester of claim 1 , further comprising:
a magnetic shield portion having a space which is shielded from an external magnetic field,
wherein the magnetic memory, the interface portion, and the magnetic field generating portion are provided in the space.
8. A tester comprising:
a controller which generates a test signal for testing a magnetic memory having a magnetoresistive element;
an interface portion which functions as an interface between the controller and the magnetic memory; and
a magnetic field generating portion which applies a test magnetic field to the magnetoresistive element,
wherein the controller is configured to:
execute a first step in which a first data is written to the magnetoresistive element;
execute a second step in which a second data is read from the magnetoresistive element in a state of applying the test magnetic field to the magnetoresistive element, after executing the first step; and
execute a third step in which a characteristic of the magnetoresistive element is evaluated by comparing the first and second data, after executing the second step.
9. The tester of claim 8 , wherein the test magnetic field is directed in a direction of θ to a magnetization direction of the magnetoresistive element, where 0°≦θ≦90°.
10. The tester of claim 8 , wherein the test magnetic field has an intensity lower than an intensity of a reversal magnetic field which is reversed to a magnetization direction of a storage layer of the magnetoresistive element.
11. The tester of claim 8 , wherein the magnetoresistive element is provided on a semiconductor substrate, and has a magnetization direction which is perpendicular to a surface of the semiconductor substrate.
12. The tester of claim 8 , wherein the magnetic field generating portion comprises a permanent magnet or an electromagnet controlled by the controller.
13. The tester of claim 8 , wherein the interface portion includes a probe which contacts with an electrode of the magnetic memory while the magnetic memory is tested by the test signal, and a holder having a first surface and a second surface, the holder holding the probe in the first surface.
14. The tester of claim 8 , further comprising:
a magnetic shield portion having a space which is shielded from an external magnetic field,
wherein the magnetic memory, the interface portion, and the magnetic field generating portion are provided in the space.
15. A tester comprising:
a controller which generates a test signal for testing a magnetic memory having a magnetoresistive element;
an interface portion which functions as an interface between the controller and the magnetic memory; and
a magnetic field generating portion which applies a test magnetic field to the magnetoresistive element,
wherein the controller is configured to:
execute a first step in which a first data is written to the magnetoresistive element in a state of applying the test magnetic field to the magnetoresistive element;
execute a second step in which a second data is read from the magnetoresistive element, after executing the first step; and
execute a third step in which a characteristic of the magnetoresistive element is evaluated by comparing the first and second data, after executing the second step.
16. The tester of claim 15 , wherein the test magnetic field is directed in a direction of 0 to a magnetization direction of the magnetoresistive element, where 0°<0<90°.
17. The tester of claim 15 , wherein the test magnetic field has an intensity lower than an intensity of a reversal magnetic field which is reversed to a magnetization direction of a storage layer of the magnetoresistive element.
18. The tester of claim 15 , wherein the magnetoresistive element is provided on a semiconductor substrate, and has a magnetization direction which is perpendicular to a surface of the semiconductor substrate.
19. The tester of claim 15 , wherein the magnetic field generating portion comprises a permanent magnet or an electromagnet controlled by the controller.
20. The tester of claim 15 , wherein the interface portion includes a probe which contacts with an electrode of the magnetic memory while the magnetic memory is tested by the test signal, and a holder having a first surface and a second surface, the holder holding the probe in the first surface.
21. The tester of claim 15 , further comprising:
a magnetic shield portion having a space which is shielded from an external magnetic field,
wherein the magnetic memory, the interface portion, and the magnetic field generating portion are provided in the space.