Measuring and testing – Surface and cutting edge testing – Roughness
Reexamination Certificate
1998-11-27
2001-05-01
Larkin, Daniel S. (Department: 2856)
Measuring and testing
Surface and cutting edge testing
Roughness
C250S306000, C250S307000
Reexamination Certificate
active
06223591
ABSTRACT:
This application claims the benefit of Japanese patent application No. 09-344143, filed Nov. 28, 1997 and Japanese patent application No. 09-363129, filed Dec. 15, 1997, both of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to atomic force microscopes, and more particularly, to a probe needle of a probe microscope, as well as the probe microscope that utilizes the probe needle.
2. Discussion of the Related Art
The probe needle arrangement of an atomic force microscope, such as a probe microscope, is constructed from a cantilever and a probe needle part which extends from the tip end of the cantilever in a direction substantially perpendicular to the direction of length of the cantilever. An atomic force microscope detects changes in the flexing (bending amount) of the cantilever caused by an interaction force between the probe needle part and a sample surface to be detected. Changes in the flexing of the cantilever are generally detected by an optical lever method. In the optical lever method, a light beam is projected onto the cantilever surface, and the flexing of the cantilever is detected by detecting changes in the direction of reflection. The surface shape of the sample can thus be detected with a high resolution by detecting changes in the flexing of the cantilever in this manner.
In industrial fields in which probe microscopes are widely used, and especially in the semiconductor field, there is an increasing need for the control of trenches and detecting of the surface shape of these trenches formed in samples. The objects of control in such cases are the shapes of the side surfaces of the trenches and the shape of the bottoms of the trenches. Such trenches have a narrow width and a high aspect ratio.
Accordingly, a boot type probe needle in which the tip end is flared has been proposed (An example is disclosed in, Yves Martin and H. Kumar Wickramasinghe, Appl. Phys. Lett. 64 (19), May 9, 1994, pp. 2498-2500, “Method for imaging sidewalls by atomic force microscopy”). In this device, the boot type probe needle is caused to undergo minute vibrations in the longitudinal and lateral directions, and the forces acting on the probe needle from the respective directions are measured. Feedback quantities corresponding to the forces acting on the probe respectively. In this way, samples having steep surface profiles are traced by the probe needle. However, in the case of a probe needle part which has edges pointing in the lateral directions, as in the boot type short needle, it is difficult to reduce the diameter of the tip end. As a result, it is difficult to insert the probe needle into the sample's trenches. Furthermore, since the probe needle part is caused to perform a reciprocating motion in the lateral direction perpendicular to the direction of length of the probe needle part in order to detect the force, there is a limit to the width of the trenches that can be measured.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a probe needle of a probe microscope that substantially obviates one or more of the problems due to the limitations and disadvantages of the related art.
One object of the present invention is to provide a probe microscope having a probe needle which can be inserted into trenches having a smaller width and like structure.
Another object of the present invention is to provide a probe microscope having a probe needle which can be inserted into trenches having a high aspect ratio and like structure.
Additional features and advantages of the present invention will be set forth in the description which follows, and will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure and process particularly pointed out in the written description as well as in the appended claims.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, in accordance with a first aspect of the present invention there is provided a probe microscope, including a probe needle arrangement having a probe needle part, and a detection part connected to, and formed along the same axis as, the probe needle part; a displacement detector that detects changes in a condition of the probe needle part; and a movement device that drives the probe needle arrangement relative to a sample surface to be measured.
In another aspect of the present invention, there is provided a method for detecting an interaction force between a probe needle arrangement and a sample surface, the method including the steps of generating a torsional resonant vibration centered on an axis within the probe needle arrangement, the axis passing along the length of the probe needle arrangement and being substantially perpendicular to the sample surface; and detecting the interactive force from changes in the torsional resonant vibration.
In another aspect of the present invention, there is provided a probe needle arrangement movement method in a probe microscope, the method including the steps of exciting a torsional resonant vibration in the probe needle arrangement; moving the probe needle arrangement relative to a sample; detecting changes in an interaction force between the probe needle arrangement and the sample by detecting changes in the torsional resonant vibration; and determining a further direction of movement of the probe needle arrangement in a relation to a current placement of the probe needle arrangement and an amount of change in the interactive force when a change in the interactive force is detected.
In another aspect of the present invention, there is provided a method of imaging the surface profile of a sample using a probe needle arrangement of a probe microscope, the method including the steps of generating a torsional resonant vibration in the probe needle arrangement; moving the probe needle arrangement towards the sample; detecting changes in an interaction force between the probe needle arrangement and the sample by detecting changes in the torsional resonant vibration; determining a further direction of movement of the probe needle arrangement in relation to a current placement of the probe needle arrangement and an amount of changes of the current interaction force each time a change in the interaction force is detected; storing data corresponding to each of the new directions of movement determinations in a memory unit; and imaging the surface profile of the sample from the data corresponding to each of the further directions of movement determinations stored in the memory unit.
In another aspect of the present invention, there is provided a probe needle arrangement movement method in a probe microscope, the method including steps of moving the probe needle arrangement relative to a sample; detecting changes in an interaction force between the probe needle arrangement and the sample and determining a further direction of movement of the probe needle arrangement in relation to a current placement of the probe needle arrangement and an amount of change in the interactive force when a change in the interactive force is detected.
In another aspect of the present invention, there is provided a method of imaging the surface profile of a sample using a probe needle arrangement of a probe microscope, the method including steps of moving the probe needle arrangement towards the sample; detecting changes in an interaction force between the probe needle arrangement and the sample; and determining a further direction of movement of the probe needle arrangement in relation to a current placement of the probe needle arrangement and an amount of change in the interaction force when a change in the interaction force is detected.
In a further aspect of the present invention, there is provided a probe needle for use in a probe microscope, including a probe needle part; and a detection part connected to, and
Larkin Daniel S.
Morgan & Lewis & Bockius, LLP
Nikon Corporation
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