MICROSCOPY IMAGING METHOD AND SYSTEM

• US 20140226003A1
• Filed: 05/14/2012
• Published: 08/14/2014
• Est. Priority Date: 05/13/2011
• Status: Active Grant

• Current Assignee: Fibics Incorporated
• Original Assignee: Fibics Incorporated
• Inventors: Phaneuf, Michael William, Lagarec, Ken Guillaume
• Granted Patent: US 9,633,819 B2
• Time in Patent Office: Days
• US Class Current: 348/80
• CPC Class Codes: G06T 2207/10061 from scanning electron microscope
• CPC Class Codes: H01J 2237/226 Image reconstruction
• CPC Class Codes: H01J 2237/2811 Large objects
• CPC Class Codes: H01J 2237/3174 Etching microareas
• CPC Class Codes: H01J 2237/31749 Focused ion beam
• CPC Class Codes: H01J 37/222 Image processing arrangements associated with the tube image data processing or generation, in general G06T
• CPC Class Codes: H01J 37/26 Electron or ion microscopes; Electron or ion diffraction tubes
• CPC Class Codes: H01J 37/28 with scanning beams H01J37/268, H01J37/292, H01J37/2955 take precedence
• CPC Class Codes: H01J 37/3005 Observing the objects or the point of impact on the object
• CPC Class Codes: H01J 37/304 Controlling tubes by information coming from the objects or from the beam, e.g. correction signals
• CPC Class Codes: H01J 37/3045 Object or beam position registration
• CPC Class Codes: H01J 37/3056 for microworking, e.g. etching of gratings, trimming of electrical components trimming of resistors H01C17/22

Abstract

Generally, the present disclosure provides a method and system for improving imaging efficiency for CPB systems while maintaining or improving imaging accuracy over prior CPB systems. A large field of view image of a sample is acquired at a low resolution and thus, at high speed. The low resolution level is selected to be sufficient for an operator to visually identify structures or areas of interest on the low resolution image. The operator can select one or more small areas of arbitrary shape and size on the low resolution image, referred to as an exact region of interest (XROI). The outline of the XROI is mapped to an x-y coordinate system of the image, and the CPB system is then controlled to acquire a high resolution image of only the XROI identified on the low resolution image. For 3D imaging, once the XROI is identified, each section of the sample can be iteratively imaged in the previously described manner, with the operator having the option to redefine the XROI later.

Claims

1. A selective high resolution imaging method for a charged particle beam apparatus, comprising:

acquiring and displaying a sample area image of a sample at a first resolution

scanning at least one exact region of interest in the sample area image; and

acquiring and displaying an image of the at least one exact region of interest at a second resolution greater than the first resolution.

2. The method of claim 1, wherein scanning an exact region of interest includes

receiving an arbitrary outline corresponding to the exact region of interest in the sample area,

mapping the arbitrary outline to a coordinate system of the sample area image,

generating a raster pattern for directing a beam in response to the arbitrary outline, and

rastering the beam at a position of the sample corresponding to the arbitrary outline and within an area defined by the arbitrary outline.

3. The method of claim 2, wherein receiving includes receiving a second arbitrary outline corresponding to another exact region of interest.

4. The method of claim 2, further including sectioning the sample to expose a new sample surface after acquiring and displaying the image of the at least one exact region of interest.

5. The method of claim 4, further including

scanning the at least one exact region of interest of the new sample surface, and

acquiring and displaying another image of the at least one exact region of interest of the new sample surface at a second resolution greater than the first resolution.

6. The method of claim 5, wherein a sequence of sectioning, scanning, and acquiring and displaying is executed iteratively until a request for a new sample area image at a first resolution is received.

7. The method of claim 6, wherein receiving the request for a new sample area image includes receiving a new arbitrary outline corresponding to a different exact region of interest in the new sample area image.

8. The method of claim 7, wherein receiving the new arbitrary outline includes modifying the arbitrary outline.

9. The method of claim 4, wherein a focused ion beam is operated to section the sample by advancing the focused ion beam to a predetermined position and rastering the focused ion beam along a line.

10. The method of claim 9, wherein advancing the focused ion beam includes

generating a primary digital code corresponding to a primary deflection voltage for moving a position of the focused ion beam,

generating at least one additional digital code proximate to the primary digital code for generating a secondary deflection voltage, and

averaging the primary deflection voltage and the secondary deflection voltage to provide a final deflection voltage.

11. The method of claim 10, wherein the at least one additional digital code is one step greater than or less than the primary digital code, or two steps greater than or less than the primary digital code.

12. The method of claim 9 including determining a thickness of the sectioned portion of the sample by comparing a first distance between a pair of notches in a current image of the sample surface with a second distance between another pair of notches in a previous image of the sample surface.

13. The method of claim 12 further including comparing the thickness of the sectioned portion of the sample to a desired cross section thickness, and adjusting a milling rate of the focused ion beam.