Methods for performing a non-contact electrical measurement on a cell, chip, wafer, die, or logic block

Patent metadata

Field	Value
Publication number	US-11340293-B2
Application number	US-202017061352-A
Country	US
Kind code	B2
Filing date	Oct 1, 2020
Priority date	Oct 1, 2019
Publication date	May 24, 2022
Grant date	May 24, 2022

Abstract

Systems, devices, and methods for performing a non-contact electrical measurement (NCEM) on a NCEM-enabled cell included in a NCEM-enabled cell vehicle may be configured to perform NCEMs while the NCEM-enabled cell vehicle is moving. The movement may be due to vibrations in the system and/or movement of a movable stage on which the NCEM-enabled cell vehicle is positioned. Position information for an electron beam column producing the electron beam performing the NCEMs and/or for the moving stage may be used to align the electron beam with targets on the NCEM-enabled cell vehicle while it is moving.

First claim

We claim:

1. A method comprising:
receiving a recipe for a die included in a wafer, the die being divided into a plurality of tiles, each tile including a registration area and a plurality of non-contact electronic measurement (NCEM)-enabled cells, the recipe including a position for the die within the wafer, a position of the registration area, and a position for each of the NCEM-enabled cell of the plurality of NCEM-enabled cells;
determining an expected position of a registration area included in a tile of the plurality of tiles using the recipe;
instructing an electron beam column to raster scan a region of the tile corresponding to the expected position of the registration area using an electron beam;
receiving an image of the region of the tile corresponding to the expected position of the registration area that has been raster scanned;
determining an actual position of the registration area using the image;
aligning the electron beam using the actual position of the registration area;
sequentially directing the aligned electron beam toward each of NCEM-enabled cells of the plurality of NCEM-enabled cells within the tile of the plurality of tiles;
receiving a response of each of the NCEM-enabled cells to the aligned electron beam; and
providing an indication of the response to a processor.

2. The method of claim 1 , wherein the tile is a first tile, the registration area is a first registration area, the region of the tile corresponding to the expected position of the first registration area is a first region of the tile corresponding to the expected position of the first registration area, and the plurality of NCEM-enabled cells is a first plurality of NCEM-enabled cells, the method further comprising:
determining an expected position of a second registration area included in a second tile of the plurality of tiles;
instructing an electron beam column to raster scan a second region of the tile corresponding to the expected position of the second registration area using an electron beam;
receiving an image of the second region of the tile corresponding to the expected position of the second registration area that has been raster scanned;
determining an actual position of the second registration area using the image;
aligning the electron beam using the actual position of the second registration area;
sequentially directing the aligned electron beam toward each of NCEM-enabled cells of a second plurality of NCEM-enabled cells within the second tile;
receiving a response of each of the NCEM-enabled cells included in the second plurality of NCEM-enabled cells to the aligned electron beam; and
providing an indication of the response to a processor.

3. The method of claim 2 , further comprising:
determining a first difference between the expected and actual position of the first registration area;
determining a second difference between the expected and actual position of the second registration area;
determining an amount of electron beam drift of the electron beam using the first and second differences; and
using the amount of electron beam drift to align the electron beam when it is directed toward at least one of a third registration area in a third tile and an NCEM-enabled cell included in the third tile.

4. The method of claim 1 , wherein the wafer is positioned on a stage that moves while the electron beam is directed toward the registration area, the method further comprising:
receiving position information for the stage as it moves; and
adjusting a deflection angle of the electron beam on the registration area while raster scanning the registration area, the adjustment being responsive to the position information for the stage so that the raster scan of the registration area compensates for movement of the stage.

5. The method of claim 4 , wherein the position information is received from at least one of an interferometer and an optical encoder.

6. The method of claim 1 , further comprising:
receiving position information for the stage;
receiving position information for an electron beam column that generates the electron beam;
determining a position of the stage relative to the electron beam column; and
adjusting a deflection angle of the electron beam on the registration area while raster scanning the registration area responsively to the relative position between the stage and the electron beam column.

7. The method of claim 1 , wherein the wafer is positioned on a moving stage, the method further comprising:
receiving position information for the stage over a time interval;
receiving position information for an electron beam column that generates the electron beam over the time interval;
determining, a plurality of times, a position of the stage and relative to the electron beam column over the time interval; and
adjusting a deflection angle of the electron beam on the registration area over the time interval while raster scanning the registration area, the adjustment being responsive to the relative position between the stage and the electron beam column over the time interval so that the raster scan of the registration area may be compensate for the movement of the stage.

8. The method of claim 7 , further comprising:
determining an amount of column drift wherein the relative position.

9. The method of claim 7 , wherein the position information is received from at least one of an interferometer and an optical encoder.

10. The method of claim 1 , wherein the registration area includes a plurality of features and determining the expected position of the registration area comprises determining an expected position for two or more of the plurality of features and determining the actual position of the registration area comprises determining an actual position for the two or more features of the plurality of features using the image, the method further comprising:
comparing the expected and actual position for each of the two or more features to determine a difference therebetween, wherein the aligning of the electron beam is responsive to the difference.

11. The method of claim 1 , wherein tile size is responsive to at least one of a path length for the electron beam column and a size of a field of view of the electron beam column.

12. The method of claim 1 , wherein the indication of the response of the NCEM-enabled cell to the aligned electron beam is a voltage contrast measurement.

13. The method of claim 1 , wherein the indication of the response of the NCEM-enabled cell to the aligned electron beam is a detector current that indicates a measure of detected electron intensity.

14. The method of claim 13 , further comprising;
converting the detector current into a grey level.

15. A method comprising:
receiving a recipe for a die included in a wafer, the die being divided into a plurality of tiles, each tile having an exact center point and a settling window and including a registration area and a plurality of non-contact electronic measurement (NCEM)-enabled cells, the recipe including a position for the die within the wafer, a position of the registration area, and a position for each of the NCEM-enabled cell of the plurality of NCEM-enabled cells;
determining an expected position of a registration area included in a tile of the plurality of tiles using the recipe;
receiving position information for the tile;
determining whether at least one of the settling window and the exact center point is centered within a field of view of an electron beam column and, if so, instructing an electron beam column to raster scan a region of the tile corresponding t

Assignees

• Pdf Solutions Inc

Inventors

• De Indranil
• Mankos Marian
• Ciplickas Dennis
• Hess Christopher
• Cheng Jeremy
• Murugan Balasubramanian
• Hu Qi

Classifications

• G01R31/2653 Primary

  using electron beams · CPC title

• G01R31/3025

  Wireless interface with the DUT · CPC title

• G01R31/306 Primary

  of printed or hybrid circuits · CPC title

• G01R31/318511

  Wafer Test · CPC title