MEASUREMENT OF CRITICAL DIMENSIONS OF NANOSTRUCTURES USING X-RAY GRAZING INCIDENCE IN-PLANE DIFFRACTION

• US 20160266056A1
• Filed: 03/09/2016
• Published: 09/15/2016
• Est. Priority Date: 03/10/2015
• Status: Active Grant

• Current Assignee: LYRA Acquisition Holdings LLC
• Original Assignee: Lyncean Technologies, Inc.
• Inventors: Gifford, Martin A., Ruth, Ronald D., Loewen, Roderick J.
• Granted Patent: US 10,060,865 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01B 15/00 Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons characterised by the use of optical techniques G01B9/00, G01B11/00
• CPC Class Codes: G01B 2210/56 Measuring geometric parameters of semiconductor structures, e.g. profile, critical dimensions or trench depth
• CPC Class Codes: G01N 2223/6116 semiconductor wafer
• CPC Class Codes: G01N 23/201 by measuring small-angle scattering
• CPC Class Codes: G01N 23/207 Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions

Abstract

The manufactured structure is illuminated with an x-ray beam. The manufactured structure is positioned at a selected grazing angle and a selected rotation angle with respect to the x-ray beam. The selected rotation angle has been selected to enhance in-plane diffraction of reflections of the x-ray beam by the manufactured structure. A grazing in-plane diffraction beam produced by interference with the periodic feature is detected. A property of the grazing in-plane diffraction beam is determined by the critical dimension.

Claims

1. A system for analyzing a manufactured structure having a periodic feature characterized by a critical dimension including:

a x-ray beam source configured to illuminate the manufactured structure with an x-ray beam, wherein the manufactured structure is positioned at a selected grazing angle and a selected rotation angle with respect to the x-ray beam and the selected rotation angle has been selected to enhance in-plane diffraction of reflections of the x-ray beam by the manufactured structure;

a detector configured to detect a grazing in-plane diffraction beam produced by interference with the periodic feature, wherein a property of the grazing in-plane diffraction beam is determined by the critical dimension; and

a processor configured to characterize the critical dimension based on the property of the grazing in-plane diffraction beam.

2. The system of claim 1, wherein the system is utilized inline in a semiconductor manufacturing process to detect deviation of the manufactured structure from a reference.

3. The system of claim 1, wherein the manufactured structure is at least a portion of a semiconductor device.

4. The system of claim 1, wherein the x-ray beam illuminating the manufactured structure has been collimated.

5. The system of claim 1, wherein the x-ray beam illuminating the manufactured structure has not been collimated.

6. The system of claim 1, wherein divergent rays of the x-ray beam illuminating the manufactured structure have been focused on the manufactured structure.

7. The system of claim 1, wherein the x-ray beam illuminating the manufactured structure has a divergence greater than 3 milliradians.

8. The system of claim 1, wherein characterizing the critical dimension includes determining a measurement value of structure parameters of the critical dimension.

9. The system of claim 1, wherein characterizing the critical dimension includes comparing the property of the grazing in-plane diffraction beam with a model generated property of an expected grazing in-plane diffraction beam.

10. The system of claim 9, wherein the model generated property of the expected grazing in-plane diffraction beam was generated using a Parratt analytical model.

11. The system of claim 1, wherein the selected rotation angle includes an in-plane rotation angle in a plane of the manufactured structure and the in-plane rotation angle has been selected to enhance a diffraction pattern produced by the grazing in-plane diffraction beam when in-plane reflected x-ray paths are superposed.

12. The system of claim 1, wherein the detector is a two-dimensional detector including scintillator-coupled CCDs.

13. The system of claim 1, wherein detecting the grazing in-plane diffraction beam includes detecting a diffraction pattern caused at least in part by multiple reflections of a single ray on multiple surfaces of the periodic feature.

14. The system of claim 1, wherein detecting the grazing in-plane diffraction beam includes detecting a Laue-Bragg diffraction.

15. The system of claim 1, wherein the property of the grazing in-plane diffraction beam includes one or more of the following:

an intensity, an angle, and a position.

16. The system of claim 1, wherein the critical dimension includes one or more of the following:

a sidewall angle, a line height, a linewidth, a pitch, and a roughness.

17. The system of claim 1, wherein characterizing the critical dimension includes aggregating properties of grazing in-plane diffraction beams detected at different measurement instances corresponding to different rotation angles.

18. The system of claim 1, wherein characterizing the critical dimension includes detecting one or more peaks of a plot of the property of the grazing in-plane diffraction beam.

19. A method for analyzing a manufactured structure having a periodic feature characterized by a critical dimension including:

illuminating the manufactured structure with an x-ray beam, wherein the manufactured structure is positioned at a selected grazing angle and a selected rotation angle with respect to the x-ray beam and the selected rotation angle has been selected to enhance in-plane diffraction of reflections of the x-ray beam by the manufactured structure;

detecting a grazing in-plane diffraction beam produced by interference with the periodic feature, wherein a property of the grazing in-plane diffraction beam is determined by the critical dimension; and

characterizing the critical dimension based on the property of the grazing in-plane diffraction beam.

20. A computer program product for analyzing a manufactured structure having a periodic feature characterized by a critical dimension, the computer program product being embodied in a tangible computer readable storage medium and comprising computer instructions for:

illuminating the manufactured structure with an x-ray beam, wherein the manufactured structure is positioned at a selected grazing angle and a selected rotation angle with respect to the x-ray beam and the selected rotation angle has been selected to enhance in-plane diffraction of reflections of the x-ray beam by the manufactured structure;

detecting a grazing in-plane diffraction beam produced by interference with the periodic feature, wherein a property of the grazing in-plane diffraction beam is determined by the critical dimension; and

characterizing the critical dimension based on the property of the grazing in-plane diffraction beam.