Scanning probe microscope and method of controlling the same

Abstract

A scanning probe microscope includes a measurement unit including a measurement probe, and a controller that controls the measurement unit. The controller determines a predicted value of a sum of amounts of drift in measurement when measurement is started at a timing at which an instruction is obtained, in a case where the instruction to start measurement is obtained. The predicted value is based on reference information that specifies a temporal change in the amount of drift. The controller starts measurement in a case where the predicted value is less than a threshold value set in advance, and avoids starting measurement in a case where the predicted value is equal to or greater than the threshold value.

Description

Technical Field

[0001] This invention relates to scanning probe microscopy, and more particularly, to drift in scanning probe microscopy. Background Technology

[0002] In scanning probe microscopy, the deviation in the positional relationship between the probe and the sample that occurs during measurement is considered drift.

[0003] Previously, various techniques have been proposed to reduce the effects of drift in measurements using scanning probe microscopes. For example, Japanese Patent Application Publication No. 2007-278896 (Patent Document 1) discloses a scanning probe microscope that utilizes three-dimensional information of the sample's surface shape and correction data for temperature drift. This scanning probe microscope acquires three-dimensional information of the sample, calculates a probe scanning trajectory based on this three-dimensional information and correction data, and moves the probe according to this probe scanning trajectory.

[0004] Furthermore, Japanese Patent Application Publication No. 2016-032290 (Patent Document 2) discloses a drift correction method for a scanning probe microscope. This method comprises four steps. In the first step, a shape measurement along a scan line on the sample surface is performed by scanning the probe along that scan line, and the probe is moved to the next scan line, repeating these operations. In the second step, after the shape measurement along a specific scan line in the first step is completed, a reference shape is measured along a pre-set reference shape measurement scan line relative to the sample surface by scanning the probe along that scan line. In the third step, the current reference shape measurement result from the second step is compared with a previous reference shape measurement result, and the amount of drift due to the passage of time between the two is calculated. Finally, in the fourth step, the current shape measurement result obtained in the first step is corrected based on the drift amount calculated in the third step.

[0005] Existing technical documents Patent documents [Patent Document 1] Japanese Patent Application Publication No. 2007-278896 [Patent Document 2] Japanese Patent Application Publication No. 2016-032290 Summary of the Invention The technical problem that the invention aims to solve In the aforementioned prior art, correction data is generated based on the drift that occurs. However, if the amount of drift is too large, problems may arise that cannot be avoided by using only the correction data. For example, if the drift is too large and causes the probe to get too close to the sample, damage to the probe and / or sample may occur during scanning. If the drift is too large and causes the probe and sample to be too far apart, meaningless measurement results may result.

[0006] The present invention was conceived in view of the above-mentioned actual situation, and its purpose is to provide a technique for more reliably avoiding problems that may be caused by drift in scanning probe microscopy.

[0007] Solution to the above technical problems A scanning probe microscope according to one aspect of this disclosure includes: a measurement unit comprising a measurement probe; and a controller for controlling the measurement unit, wherein the controller, upon receiving an instruction to start measurement, determines a predicted value of the sum of drift amounts in the measurement at the time the instruction is received, the predicted value being based on reference information of the time variation of a specified drift amount; the controller starts measurement if the predicted value is less than a preset threshold, and avoids starting measurement if the predicted value is above the threshold.

[0008] The control method for a scanning probe microscope according to one aspect of this disclosure is a computer-implemented control method for a scanning probe microscope, comprising: a step of acquiring an instruction for starting a measurement; a step of calculating a predicted value of the sum of drift amounts during the measurement when the instruction is acquired and the measurement is started; and a step of determining whether to start the measurement based on the predicted value, wherein the predicted value is based on reference information of the time variation of a specified drift amount, and in the determination step, if the predicted value is less than a preset threshold, the measurement is started, and if the predicted value is above the threshold, the measurement is avoided.

[0009] Invention Effects According to one aspect of this disclosure, a technique is provided for more reliably avoiding problems that may arise from drift in scanning probe microscopy. Attached Figure Description

[0010]

【 Figure 1 The figure shown is an example of the configuration of a scanning probe microscope.

[0011]

【 Figure 2 The figure shown is an example of the scanning mode of probe 114.

[0012]

【 Figure 3 The figure shown is an example of the time-varying drift in a scanning probe microscope 1.

[0013]

【 Figure 4 The above is a flowchart of an example of the processing that begins when the initialization is completed upon power-on in a scanning probe microscope 1.

[0014]

【 Figure 5 [ ] is a flowchart of the subroutine of step S70.

[0015]

Figure 6

[0016] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, the same or equivalent parts are given the same reference numerals in the drawings, and their descriptions will not be repeated.

[0017] [Components of a scanning probe microscope] Figure 1 This diagram illustrates an example of the configuration of a scanning probe microscope. An example of a scanning probe microscope is an atomic force microscope. Furthermore, scanning probe microscopes can also be other types of scanning probe microscopes (e.g., scanning tunneling microscopes). Figure 1 In the diagram, the Z-axis direction represents the height direction of the sample, while the X-axis and Y-axis directions represent directions orthogonal to the Z-axis direction.

[0018] Reference Figure 1 The scanning probe microscope 1 includes a measurement unit 100 and a controller 150.

[0019] The controller 150 includes a computer 132, a scan signal generator 133, a storage device 134, a display device 135, and an input device 136.

[0020] In one implementation, computer 132 includes at least one processor, and display device 135 displays the results of operations performed by the at least one processor. Input device 136 inputs signals corresponding to user operations to computer 132. Storage device 134 non-temporarily stores programs executed by the processor.

[0021] Computer 132 controls the operation of scanning probe microscope 1 as a whole. As described later, when receiving a measurement instruction for a sample, computer 132 can calculate a predicted value of the drift amount that occurs from the start of the measurement at the time the instruction is received until the end of the measurement, and can start the measurement corresponding to the instruction if the predicted value is less than a preset threshold. Furthermore, if the predicted value is above the threshold, computer 132 can avoid starting the measurement corresponding to the instruction.

[0022] The measurement unit 100 includes: a sample stage 112 for placing a sample 110; a piezoelectric scanner 111 for displacing the sample stage; a cantilever 113 with a probe 114 formed at its front end; a displacement detection mechanism 120 for detecting the displacement of the cantilever 113; and a feedback signal generator 131.

[0023] The piezoelectric scanner 111 includes a Z scanner 111z that generates displacement in the Z direction based on a voltage value Vz, and an XY scanner 111xy that generates displacement in the XY direction based on voltage values ​​Vx and Vy.

[0024] The displacement detection mechanism 120 includes a laser diode 115 and a photodetector 119. In the scanning probe microscope 1, when the tip of the probe 114 is brought close to the sample 110 for surface observation, the laser emitted from the laser diode 115 is reflected on the back of the cantilever 113, and the reflected light is received by the photodetector 119. As the probe 114 is gradually brought closer to the surface of the sample 110, the cantilever 113 flexes like a leaf spring. The amount of flexure (displacement on the Z-axis) is observed at the position where the photodetector 119 receives the light.

[0025] The feedback signal generator 131 receives the detection signal from the photodetector 119. Based on the detection signal, the feedback signal generator 131 calculates the deflection of the cantilever 113. The feedback signal generator 131 controls the Z-axis position of the sample so that the atomic force between the probe 114 and the surface of the sample 110 remains constant. Based on the deflection of the cantilever 113, the feedback signal generator 131 calculates the voltage value Vz that displaces the piezoelectric scanner 111 in the Z-axis direction and outputs it to the Z-scanner 111z.

[0026] The scanning signal generator 133 calculates the voltage values ​​Vx and Vy in the X-axis and Y-axis directions according to a predetermined scanning mode, so that the sample 110 moves relative to the probe 114 in the XY plane, and outputs them to the XY scanner 111xy.

[0027] A signal (deviation signal Sd) reflecting the feedback amount in the Z-axis direction is sent to computer 132 and stored in storage device 134. Based on the deviation signal Sd, computer 132 calculates the displacement of the surface caused by the unevenness of sample 110. At various positions in the X and Y axes, computer 132 reconstructs a three-dimensional image of the sample surface by calculating the displacement and displays it on the screen of display device 135. The data of this three-dimensional image is also stored in storage device 134. The data includes coordinates representing the position in the XY plane and the sample height at those coordinates. Computer 132 can read the data of the three-dimensional image stored in storage device 134 at any time and display it on display device 135. Computer 132 can perform height correction on the data of the three-dimensional image as needed and display it on display device 135.

[0028] [Threshold] The “threshold” used to determine whether to start the measurement when the computer 132 receives a measurement instruction for the sample is explained.

[0029] Drift may occur in scanning probe microscopy 1. If the amount of drift that may occur during measurement is too large, the probe will get too close to the sample, which may result in damage to the probe and / or the sample during scanning. In addition, if the amount of drift that may occur during measurement is too large, the probe and the sample will get too far apart, which may result in meaningless measurement results.

[0030] On the other hand, in the scanning probe microscope 1, the amount of drift that would cause the aforementioned "damage to the probe and / or sample during scanning" or "meaningless measurement results" is set as a "threshold".

[0031] Upon receiving a measurement instruction for a sample, computer 132 calculates a predicted value for the amount of drift that would occur between the start and end of the measurement if the measurement were to begin immediately. If the calculated predicted value is less than the aforementioned threshold, computer 132 may begin the measurement immediately in response to receiving the instruction. If the calculated predicted value is greater than the aforementioned threshold, computer 132 may avoid starting the measurement at the time the instruction is received.

[0032] [Scanning Mode] Figure 2 This is a diagram illustrating an example of the scanning mode of probe 114. Figure 2 In this context, the measurement area of ​​sample 110 is denoted as measurement range R1. Measurement range R1 represents the extent of the surface of sample 110 in relation to the three-dimensional image acquired for sample 110.

[0033] The scanning mode of probe 114 includes one or more lines, such as "line 1", "line 2", "line 3", etc. In the scanning probe microscope 1, probe 114 moves relative to sample 110. That is, only probe 114 can move, only sample 110 can move, or both probe 114 and sample 110 can move. In the following explanation, for ease of description, we will assume that probe 114 moves when describing the scanning mode of probe 114.

[0034] In "line 1", probe 114 follows line L11 in the negative direction of the Y-axis (towards) Figure 2 After moving (towards the lower side), follow line L12 in the positive direction of the Y-axis (towards the lower side). Figure 2 (In the direction of the upper side). That is, in "line 1", probe 114 moves back and forth along the Y-axis. Afterwards, probe 114 moves along line L10 in the positive direction of the X-axis (towards the upper side). Figure 2Move to the right.

[0035] Then, probe 114 moves back and forth along the Y-axis in "line 2" and along the X-axis, and then back and forth along the Y-axis in "line 3". Probe 114 scans the entire measurement range R1 by repeating this back and forth movement along the Y-axis and along the X-axis.

[0036] exist Figure 2 In the example, the Y-axis direction constitutes an example of the "main scanning direction." The X-axis direction is the direction that intersects with the main scanning direction, constituting an example of the secondary scanning direction.

[0037] [Prediction curve of drift amount] Figure 3 This is a graph showing an example of the time-varying amount of drift in scanning probe microscope 1. Figure 3 In the diagram, the vertical axis represents the drift per unit time, and the horizontal axis represents the elapsed time from the completion of initialization when the power is turned on in the scanning probe microscope 1. Figure 3 In the middle, line LP represents the predicted curve of the time change of drift.

[0038] exist Figure 3 In the example, the prediction curve is represented by line LP. As shown by line LP, the drift per unit time decreases as time passes. More specifically, the drift per unit time at times T1, T2, T3, and T4 is represented by values ​​D1, D2, D3, and D4, respectively. Value D2 is less than value D1, value D3 is less than value D2, and value D4 is less than value D3.

[0039] In one implementation example, the predicted value for the amount of drift occurring in a measurement spanning a certain length of time from a certain moment is determined based on the amount of drift per unit time at that moment and the length of that time. For example, the predicted value for the amount of drift in a measurement spanning time TA from moment T1 is determined as the product of the value D1 (the amount of drift per unit time at moment T1) and time TA. When the predicted value is determined in this way, in Figure 3 In the example, the predicted value for the amount of drift that occurs in a certain measurement decreases as the starting time becomes later. That is, the predicted value is smaller starting from time T2 than starting from time T1, smaller starting from time T3 than starting from time T2, and smaller starting from time T4 than starting from time T3.

[0040] Furthermore, in this embodiment, the line LP is an example of information specifying the time-varying change of the drift amount (hereinafter also referred to as "reference information"). The reference information may not necessarily have the form of a function, but may have other forms. An example of other forms is the drift amount over multiple time periods from the completion of the above initialization (drift amount Q0 for the time period from 0 minutes to 1 minute, drift amount Q1 for the time period from 1 minute to 2 minutes, drift amount Q2 for the time period from 2 minutes to 3 minutes, drift amount Q3 for the time period from 3 minutes to 4 minutes, ...).

[0041] In one implementation example, reference information is stored in storage device 134. Computer 132 can use this information in storage device 134 to calculate the predicted value of the aforementioned drift amount. Furthermore, reference information can also be stored in a storage device located outside the scanning probe microscope 1, as long as it is accessible to computer 132.

[0042] [Generation of reference information (information specifying the time-varying nature of the drift)] The reference information can be pre-generated and stored in storage device 134, or it can be generated by computer 132. An example of a method for generating reference information is described below.

[0043] First, the computer 132 continuously measures the deflection of the probe 114 within a given time period. At this time, in the scanning probe microscope 1, the position of the sample stage 112 is adjusted so that the probe 114 comes into contact with the sample 110.

[0044] Furthermore, based on the measurement results of the deflection, the computer 132 determines the drift amount at multiple points in time. For example, as the drift amount one minute after initialization, the change in deflection (displacement on the Z-axis) from the completion of initialization of the scanning probe microscope 1 to one minute later is determined. In addition, as the drift amount two minutes after initialization, the change in deflection from one minute to two minutes after initialization is determined.

[0045] Computer 132 arranges the multiple drift quantities determined as described above on the time axis, obtains the quadratic curve obtained by approximation of the quadratic curve, and stores the obtained quadratic curve as reference information in storage device 134.

[0046] Furthermore, the approximation method used in generating the reference information is not limited to the quadratic curve approximation. However, by generating the reference information through the quadratic curve approximation, a suitable representation of the drift amount change assumed to occur in a typical scanning probe microscope 1 can be generated through relatively simple calculations.

[0047] [Processing flow] The following describes the processing flow implemented in computer 132. Figure 4 This is a flowchart illustrating an example of the processing that begins upon completion of initialization when the power is turned on in a scanning probe microscope 1. In one implementation example, Figure 4 The processing is achieved by the processor of computer 132 executing a given program. The following is a description of... Figure 4 The processing content will be explained.

[0048] In step S10, computer 132 determines whether an instruction has been input. Instructions to computer 132 can be input through operation of input device 136, from an external device, or according to a pre-set configuration (e.g., a timer). Computer 132 repeats step S10 until it determines that an instruction has been input (in step S10, this is incorrect). If it determines that an instruction has been input (in step S10, this is correct), control proceeds to step S20.

[0049] In step S20, the computer 132 determines the content of the input instruction.

[0050] In step S30, computer 132 determines whether the input instruction is an instruction to generate reference information. If computer 132 determines that the input instruction is an instruction to generate reference information (yes in step S30), it advances control to step S40; otherwise, it advances control to step S50.

[0051] In step S40, computer 132 generates reference information. Afterwards, computer 132 returns control to step S10.

[0052] In step S50, computer 132 determines whether the input instruction is a measurement instruction. If computer 132 determines that the input instruction is a measurement instruction (yes in step S50), it advances control to step S70; otherwise, it advances control to step S60.

[0053] In step S60, after the computer 132 performs the action according to the input instructions, it returns control to step S10.

[0054] In step S70, computer 132 processes the measurement indication. The content of step S70 is as follows: Figure 5 This will be described later. Afterwards, computer 132 returns control to step S10.

[0055] Figure 5 This is the flowchart of the subroutine for step S70. (Refer to...) Figure 5 The content of step S70 will be explained.

[0056] In step S700, computer 132 reads the conditions for the indicated measurement. The measurement conditions can be entered into computer 132 along with the measurement instruction, or they can be pre-registered in computer 132.

[0057] In step S702, the computer 132 calculates the predicted amount of drift that will occur during the measurement under the conditions read in step S700, provided that the measurement is started immediately.

[0058] When calculating the predicted value, computer 132 first determines (estimates) the length of time required for the measurement. The length of time required for the measurement can be determined based on parameters included in the measurement conditions.

[0059] In one implementation example, the measurement conditions include the number of three-dimensional images acquired during the measurement. If the time required to acquire one three-dimensional image has been determined, the product of that time and the number of three-dimensional images acquired during the measurement is determined as the length of the measurement time. However, in the scanning probe microscope 1, the number of three-dimensional images acquired during the measurement can also be fixed at "1". In this case, the measurement conditions do not need to include the number of three-dimensional images acquired during the measurement.

[0060] The time required to acquire one three-dimensional image can be recorded as a fixed value in the scanning probe microscope 1. The time required to acquire one three-dimensional image can also be recorded as a fixed value for each of multiple sample types. In this case, if the measurement conditions include the sample type, the computer 132 can use that type to determine the time required to acquire one three-dimensional image.

[0061] In one implementation example, the measurement conditions include the scan speed in the main scan direction. If the scan speed in the main scan direction and the number of pixels in the sub-scan direction are determined... Figure 2 The "number of lines" in the image can be used to determine the time required to measure one sample based on the scanning speed, the number of pixels, and the scanning speed.

[0062] In one implementation example, the measurement conditions include the number of pixels in the sub-scanning direction. If the scan speed in the main scan direction is determined, the computer 132 can use these and the scan speed to determine the time required to acquire one 3D image.

[0063] In addition, at least one of the scanning distance and scanning speed in the main scanning direction and the number of pixels in the sub-scanning direction can be registered as a fixed value in the scanning probe microscope 1.

[0064] Furthermore, the computer 132 uses the length of the measurement time and reference information to calculate the sum of the drift from the start to the end of the measurement as a predicted value.

[0065] For example, in using Figure 3 When the line LP is used as reference information, the computer 132 calculates the product of the "drift per unit time" and the "time required for measurement" at that moment in the quadratic function defined by the line LP as the predicted value. For example, if a measurement indication is obtained 1 minute after the initialization is completed when the power is turned on, and the length of the time required for measurement is 2 minutes, the computer 132 calculates the product of the "drift per unit time" for 1 minute and "2 minutes" in the quadratic function as the predicted value.

[0066] In step S704, computer 132 determines whether the predicted value calculated in step S702 is less than a preset threshold. If computer 132 determines that the predicted value is less than the threshold (yes in step S704), it advances control to step S710; if it is not less than the threshold (no in step S704), it advances control to step S706.

[0067] In step S706, computer 132 calculates the start time. The start time refers to the earliest time when the predicted value of the drift amount that will occur in the measurement is less than a threshold if the measurement is started at that time.

[0068] For example, consider the following scenario: Computer 132 receives a measurement instruction 2 minutes after initialization is complete, the measurement takes 5 minutes, and registers it. Figure 3 The line LP is used as reference information. In this case, the computer 132 first calculates the product of "drift per unit time" and "5 minutes" for the function of the line LP, starting 2 minutes after initialization. When the product is above a threshold, the computer 132 implements the control in step S706. In step S706, the computer 132 calculates the product of "drift per unit time" and "5 minutes" starting 3 minutes after initialization. When the product is above a threshold, the computer 132 further calculates the product of "drift per unit time" and "5 minutes" starting 4 minutes after initialization. If the product is less than the threshold, the computer 132 determines the timing 4 minutes after initialization as the "startable timing".

[0069] In step S708, computer 132 notifies when it is ready to begin. The notification can be a display on display device 135, an audio output, a notification sent to a user registered with computer 132 (e.g., a user who entered a measurement instruction), or a combination thereof. Afterwards, computer 132 returns control to... Figure 4 .

[0070] On the other hand, in step S710, computer 132 causes measurement unit 100 to begin the indicated measurement.

[0071] Furthermore, in step S712, the computer 132 waits until it determines that the measurement in the measurement unit 100 has ended (no in step S712). If it determines that the measurement has ended (yes in step S712), then control is returned to the computer. Figure 4 .

[0072] According to the processing described above, the generation of reference information (step S40) is performed on the condition that the computer 132 acquires the generation instruction. Furthermore, the triggering condition for reference information generation is not limited to the acquisition of the instruction. Reference information generation can also be performed each time a measurement instruction is input, or it can be performed automatically in response to the completion of the initialization of the scanning probe microscope 1 (without requiring a specific instruction). Furthermore, if default reference information is registered in the scanning probe microscope 1, the generation of reference information can be omitted. However, if reference information is generated in the scanning probe microscope 1, the generated reference information can reflect the individual differences of the scanning probe microscope 1. Moreover, when a user uses the scanning probe microscope 1 in a special environment, the generated reference information can reflect that special environment of the scanning probe microscope 1.

[0073] Furthermore, in the processing described above, if it is determined in step S704 that the predicted value is above the threshold, an operation is performed to move the probe 114 away from the sample 110. Then, when the measurement begins in step S710, an operation is performed to move the probe 114 closer to the sample 110. These operations can be performed, for example, manually by the user.

[0074] According to the processing described above, when the computer 132 receives a measurement instruction, it calculates a predicted value as the sum of the predicted drift amounts that may occur during the measurement. If the predicted value is less than a preset threshold, the computer 132 causes the measurement unit 100 to start measuring. On the other hand, if the predicted value is greater than the preset threshold, the computer 132 does not cause the measurement unit 100 to start measuring, but returns control to... Figure 4 That is, it avoids starting the measurement immediately. This avoids starting the measurement when the sum of the drift amounts during the measurement period might reach a threshold.

[0075] According to the processing described above, when the computer 132 cannot start the measurement immediately, it calculates and notifies when the measurement can begin. The calculation and notification of the start time can also be omitted. However, if a start time is notified, the user can identify when the desired measurement can begin and can instruct the measurement again at that time.

[0076] After calculating the start time, computer 132 can instruct measurement unit 100 to begin measurement when the start time arrives. (See reference...) Figure 6 This variation will be explained. Figure 6It means Figure 5 A diagram of a variation of a subroutine.

[0077] exist Figure 6 In the example, after calculating the start time in step S706, computer 132 advances control to step S709.

[0078] In step S709, the computer 132 determines whether the moment when the startable opportunity has been determined has arrived. The computer 132 maintains control in step S709 until it is determined that the moment when the startable opportunity has been determined has arrived (no in step S709). If it is determined that the moment has arrived (yes in step S709), control is advanced to step S710. In step S710, the computer 132 causes the measurement unit 100 to start measuring.

[0079] In the above explanation Figure 6 In the example where the measurement cannot begin immediately according to the input instruction due to the relationship between the predicted value and the threshold, the computer 132 initiates the measurement unit 100 to begin measurement without requiring new input when the opportunity to begin arrives. Thus, in the scanning probe microscope 1, once an instruction is input, the measurement automatically begins in response to the arrival of the opportunity when the sum of the predicted drift amounts occurring during the measurement does not exceed the threshold.

[0080] Based on the processing described above, the predicted value can be calculated according to the measurement conditions. Therefore, in the scanning probe microscope 1, depending on the content of the indicated measurement, there are cases where the measurement begins immediately after being indicated, and cases where the measurement does not begin immediately.

[0081] In computer 132, instead of step S706, or in addition to step S706, the maximum number of images that can be measured immediately at the indicated time point can be determined.

[0082] For example, consider the following scenario: the measurement condition is that the number of images acquired includes "10". If the predicted value calculated based on the number of "10" images is above a threshold, computer 132 calculates a new predicted value based on the number of "9" images. If the predicted value calculated based on the number of "9" images is above the threshold, computer 132 further calculates a new predicted value based on the number of "8" images. If the predicted value calculated based on the number of "8" images is below the threshold, computer 132 determines "8" images as the maximum number of images for which measurement can begin immediately.

[0083] Furthermore, in computer 132, the maximum number of sheets can be notified instead of step S708, or in any other way.

[0084] By notifying the user of the maximum number of images, the user re-enters a measurement instruction to the scanning probe microscope 1, specifying the number of images to be acquired, including the maximum number of images. This allows the user to immediately initiate measurements to acquire the maximum number of three-dimensional images available at the time the instruction was issued.

[0085] In addition, computer 132 in Figure 6 In the processing, the maximum number of images can be determined instead of step S706, skipping step S709, and in step S710, the measurement unit 100 can begin measuring the maximum number of images. At this time, the computer 132 can notify that there is a difference in the number of three-dimensional images acquired between the indicated measurement and the measurement started by the measurement unit 100 as instructed by the computer 132.

[0086] [plan] Those skilled in the art will understand that the above-described exemplary embodiments are specific examples of the following solutions.

[0087] (Item 1) A scanning probe microscope according to one embodiment may include: a measurement unit comprising a measurement probe; and a controller for controlling the measurement unit, wherein the controller, upon receiving an instruction to start a measurement, determines a predicted value of the sum of drift amounts in the measurement at the time the instruction is received, the predicted value being based on reference information of the time variation of a specified drift amount, and the controller starts the measurement if the predicted value is less than a preset threshold, and avoids starting the measurement if the predicted value is above the threshold.

[0088] According to the scanning probe microscope described in claim 1, a technique is provided for more reliably avoiding problems that may arise from drift in a scanning probe microscope.

[0089] (Item 2) In the scanning probe microscope described in Item 1, the controller can determine, based on the reference information, the earliest start time when the sum of the drift amounts up to the end of the measurement is less than the threshold, and in response to the arrival of the earliest start time, cause the measurement unit to start the measurement.

[0090] According to the scanning probe microscope described in item 2, even if the start of measurement is avoided when the measurement instruction is obtained, the measurement can be started automatically as soon as the earliest start time arrives.

[0091] (Item 3) In the scanning probe microscope described in Item 1 or Item 2, the controller may, based on the reference information, determine the earliest start time when the sum of the drift amounts up to the end of the measurement is less than the threshold, and notify the earliest start time.

[0092] According to the scanning probe microscope described in item 3, even if the start of measurement is avoided when the measurement instruction is obtained, the user can identify the earliest start time.

[0093] (Item 4) In any one of the scanning probe microscopes in items 1 to 3, when determining the predicted value, the controller may calculate the product of the drift per unit time and the length of the time required for the measurement as the predicted value.

[0094] According to the scanning probe microscope described in item 4, the predicted value can be calculated using a simple method.

[0095] (Item 5) In the scanning probe microscope described in Item 4, the controller can acquire the conditions of the measurement and, when determining the predicted value, determine the length of time required for the measurement based on the conditions of the measurement as the time from the start to the end of the measurement.

[0096] According to the scanning probe microscope described in item 5, information (predicted value) is generated based on the measurement conditions to determine whether to perform the measurement when a measurement indication is obtained. Thus, the determination result of whether to perform the measurement when a measurement indication is obtained is based on the measurement conditions.

[0097] (Item 6) In the scanning probe microscope described in Item 5, the conditions for the measurement include at least one of the number of images acquired in the measurement, the scanning speed in the main scanning direction, and the number of pixels acquired in the direction intersecting the main scanning direction.

[0098] According to the scanning probe microscope described in item 6, the judgment result of whether to perform the measurement when the measurement indication is obtained can reflect the measurement conditions.

[0099] (Item 7) In any one of items 1 to 6, the controller can acquire multiple drift quantities corresponding to multiple time points and generate the reference information predicted from the multiple drift quantities.

[0100] According to the scanning probe microscope described in item 7, individual differences in scanning probe microscopes can be reflected in the reference information.

[0101] (Item 8) In the scanning probe microscope described in Item 7, the reference information may be a quadratic curve approximately obtained by using the quadratic curves of the plurality of drift amounts.

[0102] According to the scanning probe microscope described in item 8, reference information that appropriately represents the change in the amount of drift assumed to occur in a typical scanning probe microscope can be generated through relatively simple calculations.

[0103] (Item 9) In any one of items 1 to 8, the controller may, based on the reference information, determine the maximum number of images that can be measured when the instruction is acquired, and notify the maximum number.

[0104] According to the scanning probe microscope described in item 9, the user can identify the maximum number of images that can be measured at the time of obtaining the instruction.

[0105] (Item 10) A control method for a scanning probe microscope according to one embodiment may be a computer-implemented control method for a scanning probe microscope, comprising: a step of acquiring an instruction for starting a measurement; a step of calculating a predicted value of the sum of drift amounts in the measurement when the measurement is started at the time the instruction is acquired; and a step of determining whether to start the measurement based on the predicted value, wherein the predicted value is based on reference information of a time-varying drift amount, and in the determination step, if the predicted value is less than a preset threshold, the measurement is started, and if the predicted value is above the threshold, the measurement is avoided from starting.

[0106] According to the control method of the scanning probe microscope described in claim 10, a technique is provided for more reliably avoiding problems that may arise from drift in the scanning probe microscope.

[0107] (Item 11) The control method for a scanning probe microscope as described in Item 10 may further include: determining, based on the reference information, the earliest start time when the sum of the drift amounts up to the end of the measurement is less than the threshold; and the step of causing the scanning probe microscope to start the measurement in response to the arrival of the earliest start time.

[0108] According to the control method of the scanning probe microscope described in item 11, even if the start of measurement is avoided when the measurement instruction is obtained, the measurement can be started automatically as soon as the earliest start time arrives.

[0109] (Item 12) The control method for a scanning probe microscope as described in Item 10 or Item 11 may further include: determining, based on the reference information, the earliest start time when the sum of the drift amounts up to the end of the measurement is less than the threshold; and notifying the earliest start time.

[0110] According to the control method of the scanning probe microscope described in item 12, the user can identify the earliest start time even if the start of measurement is avoided when the measurement instruction is obtained.

[0111] (Item 13) In any one of the scanning probe microscope control methods in items 9 to 11, the step of calculating the predicted value may include calculating the product of the drift amount per unit time and the length of the time required for the measurement as the predicted value.

[0112] According to the control method of the scanning probe microscope described in item 13, the predicted value can be calculated using a simple scheme.

[0113] (Item 14) The control method for the scanning probe microscope described in Item 13 may further include the step of acquiring the conditions of the measurement, and the step of calculating the predicted value may include determining the length of time required for the measurement based on the conditions of the measurement as the time from the start to the end of the measurement.

[0114] According to the control method of the scanning probe microscope described in item 14, information (predicted value) is generated according to the measurement conditions for determining whether to perform the measurement when a measurement indication is obtained. Thus, the determination result of whether to perform the measurement when a measurement indication is obtained is based on the measurement conditions.

[0115] (Item 15) In the control method of the scanning probe microscope described in Item 14, the measurement conditions may include at least one of the number of images acquired in the measurement, the scanning speed in the main scanning direction, and the number of pixels acquired in the direction intersecting the main scanning direction.

[0116] According to the control method of the scanning probe microscope described in item 15, the judgment result of determining whether to perform the measurement when the measurement instruction is obtained can reflect the measurement conditions.

[0117] (Item 16) In any one of items 10 to 15, the method for controlling a scanning probe microscope may further include the step of generating the reference information based on a plurality of drift amounts corresponding to a plurality of timings.

[0118] According to the control method for scanning probe microscopy described in item 16, individual differences in scanning probe microscopy can be reflected in the reference information.

[0119] (Item 17) In the control method of the scanning probe microscope described in Item 16, the reference information may be a quadratic curve approximately obtained by using the quadratic curve of the plurality of drift amounts, and the predicted value may be the integral value of the quadratic curve from the beginning to the end of the measurement.

[0120] According to the control method of the scanning probe microscope described in item 17, reference information that appropriately represents the change in the amount of drift assumed to occur in a typical scanning probe microscope can be generated through relatively simple calculations.

[0121] (Item 18) In any one of items 10 to 17, the method for controlling a scanning probe microscope may further include: a step of determining, based on the reference information, a maximum number of images that can be started at the time the instruction is acquired; and a step of notifying the maximum number.

[0122] According to the control method of the scanning probe microscope described in item 18, the user can identify the maximum number of images that can be measured when an instruction is received.

[0123] The embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. The scope of this disclosure is defined not by the description of the embodiments above but by the claims, and is intended to include all modifications in the same sense and scope as the claims. Furthermore, it is intended that the techniques in the embodiments may be implemented individually or, as needed, in combination with other techniques in the embodiments.

[0124] Explanation of reference numerals in the attached figures 1 Scanning probe microscope, 100 Measurement unit, 110 Sample, 111 Piezoelectric scanner, 111 XY scanner, 111 Z scanner, 112 Sample stage, 113 Cantilever, 114 Probe, 115 Laser diode, 119 Photodetector, 120 Displacement detection mechanism, 131 Feedback signal generator, 132 Computer, 133 Scanning signal generator, 134 Storage device, 135 Display device, 136 Input device, 150 Controller.

Claims

1. A scanning probe microscope, comprising: A measurement unit including a measuring probe; and The controller that controls the measuring unit Upon receiving an instruction to begin measurement, the controller determines a predicted value for the sum of drift amounts in the measurement at the time the instruction was received, indicating when the measurement should begin. The predicted value is based on reference information regarding the time-varying nature of a specified drift amount. The controller initiates the measurement when the predicted value is less than a preset threshold. If the predicted value is above the threshold, the measurement should be avoided.

2. The scanning probe microscope as described in claim 1, wherein, Based on the reference information, the controller determines the earliest start time when the sum of the drift amounts up to the end of the measurement is less than the threshold, and in response to the arrival of the earliest start time, causes the measurement unit to start the measurement.

3. The scanning probe microscope as described in claim 1, wherein, Based on the reference information, the controller determines the earliest start point when the sum of the drift amounts up to the end of the measurement is less than the threshold, and notifies the earliest start point.

4. The scanning probe microscope as described in claim 1, wherein, When determining the predicted value, the controller calculates the product of the drift per unit time and the length of time required for the measurement as the predicted value.

5. The scanning probe microscope as described in claim 4, wherein, The controller acquires the conditions of the measurement and, when determining the predicted value, determines the length of time required for the measurement based on the conditions of the measurement as the time from the start to the end of the measurement.

6. The scanning probe microscope as described in claim 5, wherein, The measurement conditions include at least one of the following: the number of images acquired in the measurement, the scanning speed in the main scanning direction, and the number of pixels acquired in the direction intersecting the main scanning direction.

7. The scanning probe microscope as described in claim 1, wherein, The controller acquires multiple drift quantities corresponding to multiple timing points and generates the reference information predicted from the multiple drift quantities.

8. The scanning probe microscope as described in claim 7, wherein, The reference information is a quadratic curve approximately obtained by using the quadratic curves of the plurality of drift amounts.

9. The scanning probe microscope as described in claim 1, wherein, Based on the reference information, the controller determines the maximum number of images that can be measured when the instruction is received, and notifies the maximum number.

10. A control method for a scanning probe microscope, which is a computer-implemented control method for a scanning probe microscope, comprising: Steps to obtain instructions for starting the measurement; The step of calculating a predicted value of the sum of drift amounts in the measurement when the measurement begins at the time the instruction is received; as well as The step of determining whether to begin the measurement based on the predicted value. The predicted value is based on reference information regarding the time-varying nature of a specified drift amount. In the determination step, if the predicted value is less than a preset threshold, the measurement is started; if the predicted value is above the threshold, the measurement is avoided.

11. The control method for a scanning probe microscope as described in claim 10, wherein, Further includes: Based on the reference information, the step of determining the earliest start point when the sum of the drift amounts up to the end of the measurement is less than the threshold; and In response to the arrival of the earliest start time, the scanning probe microscope initiates the measurement step.

12. The control method for a scanning probe microscope as described in claim 10, wherein, Further includes: Based on the reference information, the step of determining the earliest start point when the sum of the drift amounts up to the end of the measurement is less than the threshold; and The steps to notify the earliest start time.

13. The control method for a scanning probe microscope as described in claim 10, wherein, The step of calculating the predicted value includes: calculating the product of the drift per unit time and the length of time required for the measurement as the predicted value.

14. The control method for a scanning probe microscope as described in claim 13, wherein, The method further includes the step of obtaining the conditions for the measurement. The step of calculating the predicted value includes determining the length of time required for the measurement based on the conditions of the measurement, as the time from the start to the end of the measurement.

15. The control method for a scanning probe microscope as described in claim 14, wherein, The measurement conditions include at least one of the following: the number of images acquired in the measurement, the scanning speed in the main scanning direction, and the number of pixels acquired in the direction intersecting the main scanning direction.

16. The control method for a scanning probe microscope as described in claim 10, wherein, The method further includes the step of generating the reference information based on multiple drift amounts corresponding to multiple time points.

17. The control method for a scanning probe microscope as described in claim 16, wherein, The reference information is a quadratic curve approximately obtained by using the quadratic curves of the plurality of drift amounts.

18. The control method for a scanning probe microscope as described in claim 10, wherein, Further includes: Based on the reference information, determine the maximum number of steps that allow the measurement of images to begin at the time the instruction is received; and Notify the maximum number of steps.

Images