Wafer alignment markers, systems, and related methods

Patent metadata

Field	Value
Publication number	US-11520240-B2
Application number	US-202117314410-A
Country	US
Kind code	B2
Filing date	May 7, 2021
Priority date	Sep 5, 2018
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

A method of aligning a wafer for semiconductor fabrication processes may include applying a magnetic field to a wafer, detecting one or more residual magnetic fields from one or more alignment markers within the wafer, responsive to the detected one or more residual magnetic fields, determining locations of the one or more alignment markers. The marker locations may be determined relative to an ideal grid, followed by determining a geometrical transformation model for aligning the wafer, and aligning the wafer responsive to the geometrical transformation model. Related methods and systems are also disclosed.

First claim

What is claimed is:

1. An alignment system, comprising:
a substrate support for supporting a wafer;
a sensor movable over the wafer and configured to detect magnetic attributes of alignment markers within the wafer; and
a controller operably coupled to the substrate support and sensor, the controller comprising:
at least one processor; and
at least one non-transitory computer-readable storage medium storing instructions thereon that, when executed by the at least one processor, cause the controller to:
receive data related to detected magnetic attributes of the alignment markers from the sensor; and
responsive to the received data, determine locations of the alignment markers within the wafer.

2. The alignment system of claim 1 , wherein the controller further comprises instructions that, when executed by the at least one processor, cause the controller to determine locations of the alignment markers within the wafer relative to an ideal grid.

3. The alignment system of claim 2 , wherein the controller further comprises instructions that, when executed by the at least one processor, cause the controller to calculate a geometrical transformation model for aligning the wafer relative to the ideal grid.

4. The alignment system of claim 3 , wherein the controller further comprises instructions that, when executed by the at least one processor, cause the controller to align the wafer using the substrate support based at least partially on the geometrical transformation model.

5. The alignment system of claim 3 , wherein the controller further comprises instructions that, when executed by the at least one processor, cause the controller to align the wafer using the substrate support responsive to the determined locations of the alignment markers.

6. The alignment system of claim 1 , wherein the sensor is selected from the group consisting of a MFM probe, a SQUID, or VSM.

7. The alignment system of claim 1 , wherein the sensor is selected from the group consisting of a Hall Effect sensor, a GMR sensor, a TMR sensor, an EMR sensor, or a spin hall sensor.

8. The alignment system of claim 1 , further comprising a magnetic source located and configured to apply a magnetic field to at least a portion of a wafer carried on the substrate support.

9. The alignment system of claim 8 , wherein the magnetic source comprises an electro magnet.

10. The alignment system of claim 1 , wherein the sensor is configured to detect residual magnetic fields emitted by the alignment markers.

11. The alignment system of claim 1 , wherein the sensor is configured to detect magnetizations of the alignment markers.

12. A wafer comprising:
a substrate comprising a semiconductor material; and
one or more alignment markers comprising at least one of a ferromagnetic material or an antiferromagnetic material or any other material or structure detectable responsive to exposure to a proximate magnetic field.

13. The wafer of claim 12 , wherein the one or more alignment markers comprise a pattern of recesses formed in a surface of the wafer, the pattern of recesses being at least partially filled with at least one of the ferromagnetic material, the antiferromagnetic material, or any other material or structure detectable responsive to exposure to a proximate magnetic field.

14. The wafer of claim 12 , wherein the one or more alignment markers have longitudinal ends aligned along one of an X-axis, a Y-axis, or a Z-axis of a Cartesian space.

15. A wafer comprising:
a substrate comprising a semiconductor material; and
one or more alignment markers comprising one or more inductively powerable circuits within recesses of a pattern within the substrate.

16. An alignment system, comprising:
a substrate support for supporting a wafer;
a sensor movable over the wafer and configured to detect responses of alignment markers within the wafer;
a magnetic source located and configured to apply a magnetic field to at least a portion of the wafer or drive a magnetization of the alignment markers within the wafer; and
a controller operably coupled to the substrate support and sensor, the controller comprising:
at least one processor; and
at least one non-transitory computer-readable storage medium storing instructions thereon that, when executed by the at least one processor, cause the controller to:
receive data related to detected responses of the alignment markers from the sensor; and
responsive to the received data, determine locations of the alignment markers within the wafer.

17. The alignment system of claim 16 , wherein the controller further comprises instructions that, when executed by the at least one processor, cause the controller to determine locations of the alignment markers within the wafer relative to an ideal grid based at least partially on the responses of the alignment markers.

18. The alignment system of claim 17 , wherein the controller further comprises instructions that, when executed by the at least one processor, cause the controller to calculate a geometrical transformation model for aligning the wafer relative to the ideal grid.

19. The alignment system of claim 18 , wherein the controller further comprises instructions that, when executed by the at least one processor, cause the controller to cause the alignment system to align the wafer responsive to the geometrical transformation model.

20. The alignment system of claim 16 , wherein the responses of the alignment markers comprise one or more of residual magnetic fields, magnetization, or photon emissions.

Assignees

• Micron Technology Inc

Inventors

• Mirin Nikolay A
• Dembi Robert
• Housley Richard T
• Zhang Xiaosong
• Harms Jonathan D
• Kramer Stephen J

Classifications

• H10W46/501

  for use before dicing · CPC title

• H10W46/301

  for alignment · CPC title

• H10P72/50 Primary

  for positioning, orientation or alignment · CPC title

• H10W46/00

  Marks applied to devices, e.g. for alignment or identification · CPC title

• G03F7/70633 Primary

  Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching · CPC title