Method for obtaining characteristics of surface to be measured, by using inclined tip, atomic force microscope for performing method, and computer program stored in storage medium in order to perform method
A method for acquiring a surface characteristic of a measuring object using a tilted tip, and an atomic force microscope for carrying out the method, are provided. The method includes acquiring a surface characteristic of the measuring object while relatively moving the tip in a first direction with respect to the surface of the measuring object using a first control method, controlling the tip to deviate from an abnormal state by a second control method set based on a predefined shape of the surface of the measuring object when at least one characteristic value obtained by the tip is out of a specific range during the acquiring, and performing the acquiring of the surface characteristic again after the controlling of the tip. The method automatically separates a tip entering the inner space of an undercut structure so that an image deep inside the undercut structure may be acquired.
1 . A method for acquiring a surface characteristic of an object using a measuring device including a tip interacting with the surface of the object, the method comprising:
acquiring a surface characteristic of the object while relatively moving the tip in a first direction with respect to the surface of the object using a first control method in a normal measuring state;
controlling the tip to deviate from an abnormal measuring state by a second control method set based on a predefined shape of the surface of the object when the abnormal measuring state is determined, the abnormal measuring state existing when at least one characteristic value obtained in the normal measuring state is out of a specific range; and
returning to the first control method if the abnormal measuring state is determined to not exist while using the second control method,
wherein, in the second control method, the tip is controlled to vibrate at a specific frequency, the at least one characteristic value including an amplitude of the vibrating tip, the abnormal measuring state determined when the amplitude is out of the specific range,
wherein the second control method is configured by combining
a first operation of relatively moving the tip in a direction opposite to the first direction with respect to the surface of the object, and
a second operation of separating the tip from the surface of the object, and
wherein the second control method is defined so that the first operation and the second operation are selectively executed as either (i) a combined operation performed simultaneously or (ii) alternating operations performed sequentially.
2 . The method of claim 1 , wherein the predefined shape of the surface is a shape of an undercut structure opened to the first direction.
3 . The method of claim 2 ,
wherein the measuring device is an atomic force microscope, and
wherein, in the first control method, the tip is controlled in a non-contact mode or tapping mode with respect to the object.
4 . The method of claim 3 ,
wherein the tip extends from a cantilever and has a distal end, and
wherein, when moving the tip to acquire the surface characteristic of the object, the distal end precedes the cantilever with respect to the first direction, and then the tip interacts with the surface of the object in a tilted state.
5 . The method of claim 4 , wherein
the tip is formed to extend from the cantilever so that the distal end is substantially straight,
the measuring device is configured to move the tip in a second direction for feedback on the surface of the object of the tip, and
the second direction is a direction tilted without being perpendicular to the first direction.
6 . The method of claim 4 , wherein
the tip is formed to be tilted from the cantilever so that the distal end is not straight,
the measuring device is configured to move the tip in a second direction for feedback on the surface of the object of the tip, and
the second direction is substantially perpendicular to the first direction.
7 . The method of claim 4 , wherein
the tip is formed to be tilted from the cantilever so that the distal end is not straight,
the measuring device is configured to move the tip in a second direction for feedback on the surface of the object of the tip, and
the second direction is a direction tilted without being perpendicular to the first direction.
8 . A computer program stored in a storage medium for performing the method of claim 1 .
9 . An atomic force microscope configured to measure a surface of an object by a probe part having a tip and a cantilever, the atomic force microscope comprising:
an XY scanner configured to move the object so that the tip relatively moves in a first direction with respect to the surface of the object;
a head configured so that the probe part may be mounted, the head including an optical system capable of measuring vibration or deflection of the cantilever and a Z scanner configured to move the probe part in at least a second direction and in a direction opposite to the second direction so as to control a distance between the tip and the surface of the object based on data obtained by the optical system; and
a controller configured to control the XY scanner and the head so as to:
acquire a surface characteristic of the object while relatively moving the tip in a first direction with respect to the surface of the object using a first control method in a normal measuring state,
control the tip to deviate from an abnormal measuring state by a second control method set based on a predefined of the surface of the object when the abnormal measuring state is determined, the abnormal measuring state existing when at least one characteristic value obtained in the normal measuring state is out of a specific range, and
return to the first control method if the abnormal measuring state is determined to not exist while using the second control method,
wherein, in the second control method, the tip is controlled to vibrate at a specific frequency, the at least one characteristic value including an amplitude of the vibrating tip, the abnormal measuring state determined when the amplitude is out of the specific range,
wherein the second control method is configured by combining
a first operation of relatively moving the tip in a direction opposite to the first direction with respect to the surface of the object, and
a second operation of separating the tip from the surface of the object, and
wherein the second control method is defined so that the first operation and the second operation are selectively executed as either (i) a combined operation performed simultaneously or (ii) alternating operations performed sequentially.
10 . The atomic force microscope of claim 9 , wherein the predefined shape of the surface is a shape of an undercut structure opened to the first direction.
11 . The atomic force microscope of claim 10 , wherein the head is configured to be tiltable, so that the tip is approached obliquely with respect to the surface of the object.
12 . The atomic force microscope of claim 9 ,
wherein the first operation is performed using the XY scanner, and
wherein the second operation is performed using the Z scanner.