SYSTEMS AND METHODS FOR CHARACTERIZING THICKNESS AND TOPOGRAPHY OF MICROELECTRONIC WORKPIECE LAYERS

• US 20090044610A1
• Filed: 08/16/2007
• Published: 02/19/2009
• Est. Priority Date: 08/16/2007
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Sandhu, Gurtej S., Mackey, Jeffrey L.
• Granted Patent: US 7,823,440 B2
• Time in Patent Office: Days
• US Class Current: 73/104
• CPC Class Codes: G01B 11/0641 with measurement of polarization
• CPC Class Codes: G01B 11/2441 using interferometry
• CPC Class Codes: G01B 21/08 for measuring thickness
• CPC Class Codes: G01B 21/20 for measuring contours or curvatures, e.g. determining profile

Abstract

Metrology systems, tools, and methods that characterize one or more layers of a microelectronic workpiece are disclosed herein. In one embodiment, a system for characterizing thickness and topography of a workpiece layer includes a layer thickness instrument configured to measure a thickness of a first workpiece layer at individual sampling sites, a surface topography instrument configured to measure a relative surface height of the first layer at the individual sampling sites, and a processing unit communicatively coupled to receive thickness and topography measurements and operable to output layer data that includes individual thickness measurements combined with individual topography measurements at workpiece coordinates corresponding to the individual sampling sites. In another embodiment, the system further includes an output device communicatively coupled with the processing unit and operable to graphically display a stratigraphic cross-section corresponding to the output layer data.

Claims

1. A system for producing layer data that characterizes one or more layers of a microelectronic workpiece, comprising:

a layer thickness instrument configured to measure a thickness of a first workpiece layer at individual sampling sites;

a surface topography instrument configured to measure a relative surface height of the first layer at the individual sampling sites; and

a processing unit operatively coupled to thickness and topography instruments to receive thickness and topography measurements, wherein the processing unit outputs layer data that includes individual thickness measurements combined with individual topography measurements at workpiece coordinates corresponding to the individual sampling sites.

2. The system of claim 1, further comprising an output device communicatively coupled with the processing unit, wherein the output device graphically displays a stratigraphic cross-section corresponding to the output layer data.

3. The system of claim 2 wherein the output device is configured to graphically display a wafer map that relates the individual sampling sites with the stratigraphic cross-section.

4. The system of claim 1, further comprising an input device operably coupled with the processing unit and configured to receive a user-configured wafer map that identifies the individual sampling sites.

5. The system of claim 1, further comprising a wafer transport system operably coupled with the thickness and topography instruments and configured to transport microelectronic workpieces to and from the thickness and topography instruments.

6. The system of claim 1, further comprising a housing, wherein the thickness and topography instruments and the processing unit are disposed within the housing.

7. The system of claim 1 wherein the processing unit is coupled to the thickness and topography instruments through a local network.

8. A computing device, comprising:

at least one communication port coupled to receive thickness measurements of a microelectronic workpiece layer at individual sampling sites and topography measurements of the workpiece layer at the individual sampling sites;

a processor coupled to the communication port; and

a memory comprising program instructions that are executable by the processor to map the individual thickness and topography measurements to individual workpiece coordinates.

9. The computing device of claim 8 wherein the communication port is coupled to at least one of a thickness instrument and a topography instrument.

10. The computing device of claim 9 wherein the program instructions are further executable by the processor to coordinate alignment of an optical system coupled to the communication port.

11. The computing device of claim 8 wherein the program instructions are further executable by the processor to approximate the individual workpiece coordinates by calculating a midpoint between workpiece coordinates associated with the individual thickness measurements and workpiece coordinates associated with the individual topography measurements.

12. A metrology tool, comprising:

a housing having an opening that is arranged to receive a microelectronic workpiece having a first layer;

an ellipsometer disposed within the housing and operably coupled with a processing unit, wherein the ellipsometer is configured to transmit thickness measurements of the first layer to the processing unit; and

an interferometer disposed within the housing and operably coupled with the processing unit, wherein the interferometer is configured to transmit topography measurements of the first layer to the processing unit.

13. The metrology tool of claim 12 wherein the processing unit is configured to output layer data that includes the individual thickness measurements, the individual topography measurements, and workpiece coordinates associated with the individual thickness and topography measurements.

14. The metrology tool of claim 12, further comprising at least one of a four-point probe and an atomic force microscope disposed within the housing and operably coupled with the processing unit.

15. A method for characterizing microelectronic workpiece layers, the method comprising:

collecting individual first datums of thickness, surface height, and workpiece coordinates corresponding to a first microelectronic workpiece layer using a thickness instrument, a topography instrument, and a computing device operably coupled with the thickness and topography instruments; and

producing a stratigraphic representation of the first workpiece layer based on the individual first datums using the computing device.

16. The method of claim 15, further comprising outputting the stratigraphic representation to at least one of graphical display and a printer.

17. The method of claim 15 wherein the first workpiece layer is a top-most layer of a microelectronic workpiece.

18. The method of claim 15 wherein the computing device coordinates the collecting of the individual first datums by a measurement process that includes:

directing the thickness instrument to measure a thickness of the workpiece layer at individual sampling sites;

directing the topography instrument to measure a relative surface height of the workpiece layer at the individual sampling sites; and

associating the individual sampling sites with individual workpiece coordinates.

19. The method of claim 18 wherein the relative surface height measurements are measured between a top-side surface of the workpiece layer and a reference height.

20. The method of claim 18 wherein the relative surface height measurements are measured between a bottom-side of the workpiece layer and a reference height.

21. The method of claim 18 wherein the measurement process is configured to store the relative surface heights of the workpiece layer prior to formation of the workpiece layer.

22. The method of claim 18 wherein associating the individual sampling sites with the individual workpiece coordinates includes approximating the individual workpiece coordinates.

23. The method of claim 15, further comprising:

collecting individual second datums of thickness, surface height, and workpiece coordinates corresponding to a second microelectronic workpiece layer using the thickness instrument, the topography instrument, and the computing device; and

producing the stratigraphic representation further based on the individual second datums using the computing device.

24. A method for providing layer data corresponding to a microelectronic workpiece layer, the method comprising:

measuring a microelectronic workpiece layer with a thickness instrument at individual sampling sites;

measuring the workpiece layer with a surface topography instrument at the individual sampling sites; and

communicating thickness and topography measurements to a processing unit that is configured to create layer data by a process that includes combining individual thickness measurements with individual surface height measurements at workpiece coordinates corresponding to the individual sampling sites.

25. The method of claim 24, further comprising using the layer data to adjust at least one semiconductor process.

26. The method of claim 24, further comprising using the layer data as a process control for at least one semiconductor process.

27. A method for stratigraphically sampling a microelectronic workpiece, the method comprising:

inputting sampling sites that are to be measured on a microelectronic workpiece layer;

measuring a thickness of the workpiece layer at the input sampling sites;

measuring a relative surface topography of the workpiece layer at the input sampling sites; and

outputting layer data that includes individual thickness measurements and individual surface height measurements associated with workpiece coordinates corresponding to individual input sampling sites.

28. The method of claim 27 wherein the input samples sites are located within a predetermined measurement area on a microelectronic workpiece.

29. The method of claim 28 wherein the predetermined measurement area includes at least one of a workpiece feature and a microelectronic die location.

30. The method of claim 27 wherein the measuring of the thickness of the workpiece layer and the measuring of the relative surface topography of the workpiece layer are carried out by a single metrology tool.

31. The method of claim 30 wherein the input sampling sites are configured to optimize a workpiece throughput times associated with the metrology tool.

32. The method of claim 27 wherein the input sampling sites are configured to optimize a resolution of the layer data.