KR100787536B1 - Calculation method of machining error correction data when processing microstructures of microstructures, processing method of microstructures to which machining error correction data is applied, and microstructure processing apparatus using FIV - Google Patents

Abstract

The present invention relates to a method for calculating processing error correction data when processing a focused ion beam (FIB) of a microstructure, an FIB processing method of a microstructure to which machining error correction data is applied, and a microstructure processing apparatus using FIB. More specifically, the FIB is used to process microstructures, generate correction data for machining errors caused by reattachment, and apply the machining error correction data to subsequent machining to effectively target at a time. The present invention relates to a method for calculating machining error correction data during FIB machining of microstructures, an FIB machining method for microstructures to which machining error correction data is applied, and a microstructure processing apparatus using FIB. According to the present invention, after FIB processing, processing error correction data due to reattachment is calculated through a control algorithm that accurately measures the reattached material shape using an image processing technique, and performs FIB correction processing accordingly. Accordingly, in the future mass production, by FIB processing using the correction data, it is possible to efficiently process the microstructures of various materials in the intended precise shape without using expensive gas.

Focused ion beam, microstructure processing, processing error correction

Description

Calculation method of machining error correction data when processing microstructure of microstructure FOCUSED ION BEAM) FABRICATION OF MICRO STRUCTURES, METHOD FOR FIB FABRICATION OF MICRO STRUCTURES USING ERROR-REDUCTION DATA AND SYSTEM FOR FIB FABRICATION OF MICRO STRUCTURES}

1 is a view showing a process of processing a microstructure using the FIB according to the present invention.

2 is a view showing a phenomenon in which the material removed by the irradiated FIB is reattached in a pocket processed in the microstructure when processing the microstructure using the FIB according to the present invention.

Figure 3 corrects this difference (hereinafter referred to as a machining error) from the shape of the distorted shape and the original intended pocket by reattachment of sputtered material into sputtered material, thereby processing the pocket in the future pocket processing. The figure which shows the calculation sequence of the processing error correction data which can process the intended pocket shape at once in consideration of the error.

4 is a diagram showing a calculation process of machining error correction data using a cross-sectional shape diagram of a pocket;

5 is a flowchart illustrating a process of calculating processing error correction data.

Figure 6 is a flow chart showing in detail the processing error measurement process by reattachment.

7 is a flowchart illustrating a pocket machining process to which machining error correction data is applied.

8 is a view showing the internal structure of the microstructure processing apparatus using FIB.

The present invention relates to a method for calculating processing error correction data, a FIB processing method for applying micro-structured correction data when processing a focused ion beam (FIB), and a microstructure processing apparatus using FIB. In more detail, the microstructure is processed using FIB, and the correction data for the machining error caused by the reattachment are generated, and the machining error correction data is applied to the subsequent machining to effectively target the target shape at once. The present invention relates to a method for calculating processing error correction data during FIB processing of microstructures, a FIB processing method for microstructures to which machining error correction data is applied, and a microstructure processing apparatus using FIB.

Recently, the production of high-performance micro components is very active in the fields of optical digital communication technology, display technology, micro-processing technology, electronics industry, and medicine. Therefore, various processes for manufacturing microstructures having a micro-nano unit size shape have been studied. For this reason, there is an increasing demand for product shape precision in the component manufacturing process.

Among them, the fabrication of microstructures using FIB has attracted new attention because it can be applied to etching and deposition processes for relatively various materials, and easy to process three-dimensional shapes.

In ion beam etching, which is a type of focused ion beam processing, gallium ions are generally used as an ion source. When an accelerated voltage is applied to the ions, they collide with the exact position on the surface of the sample to sputter (sputtering) the specific part. This is how you remove the material.

However, when processing by using the sputtering process of the three-dimensional structure, the phenomenon that a part of the removed material is attached back to the processing surface occurs, which causes the shape precision of the microstructure.

Until now, a gas assist etching process (GAE) has been used as a method for improving the shape precision of microstructures, and this method reduces the reattachment to the processed surface by inducing chemical reactivity with the material to be removed. However, because the gas used is very expensive, there are difficulties in the efficient mass production of microstructures, and the applicable materials are limited to silicon wafer series, and after the etching process, high surface quality is not obtained due to chemical reaction on the sample surface. There is a disadvantage of not being able to.

The present invention was devised to solve the above problems, and after FIB processing, through the control algorithm to accurately measure the reattached material form by using an image processing technique, and to perform the FIB correction processing according to the reattachment, By calculating the machining error correction data, the FIB processing using the correction data in the future mass production, the efficient processing of the microstructures of various materials in the intended precise shape without using expensive gas can do

In order to achieve the above object, the microstructure processing apparatus using a focused ion beam (hereinafter referred to as FIB) according to the present invention, a groove of a specific shape (hereinafter referred to as a pocket) on the surface of the microstructure A method of calculating data (hereinafter referred to as machining error correction data) for correcting a machining error due to reattachment of a removed material, which occurs when the method is executed, the method comprising: (a) initializing a machining error accumulation value; (b) irradiating the microstructure with an amount of FIB that can be processed by the intended depth of the pocket (hereinafter referred to as pocket depth); (c) the depth from the surface of the material before processing (hereinafter referred to as the horizontal plane) to the surface of the material reattached into the pocket (hereinafter referred to as processing depth), and the value obtained by subtracting the processing depth from the pocket depth (hereinafter referred to as repositioning). Measuring an error); (d) If the reattachment error is within the set allowable range, proceed to step (e). If the reattachment error is not within the allowable range, add the reattachment error to the cumulative machining error value and then from step (b). Repeating the process; and (e) storing a value obtained by adding the pocket depth to the cumulative machining error value for the microstructure as a machining error correction data in a database.

Step (c) may include: (c1) filling the pocket with a material for protecting the cut end of the pocket; (c2) cutting the cross section for measuring the reattachment error of the pocket; (c3) measuring the reattachment error of the pocket; preferably.

The material for protecting the cut end of the pocket of step (c1) may be carbon.

Preferably, the measurement of the reattachment error of the pocket in the step (c3), (c31) taking an image of the cross-section; (c32) detecting the processing depth by performing an image processing program on the image of the photographed section; (c33) determining the reattachment error of the pocket by subtracting the processing depth from the pocket depth.

According to another aspect of the present invention, the microstructure processing apparatus using the FIB by applying the machining error correction data calculated in the step (e) in the method for processing a pocket in the microstructure, (a) the user to process the fine Receiving information on the structure and the pocket; (b) reading processing error correction data previously measured in the processing of the pocket from a database; and (c) irradiating the microstructure with an amount of FIB capable of processing a depth corresponding to the processing error correction data.

After the step (c) of the method for processing the pocket in the microstructure by applying the machining error correction data, (d) by measuring the value of the intended pocket depth minus the actual machining depth (hereinafter referred to as reattachment error) If the reattachment error is not within the set allowable range, displaying the same on a monitor.

According to another aspect of the present invention, the correction value of the machining error due to the reattachment of the removed material, which occurs when processing a groove of a specific shape (hereinafter referred to as a pocket) on the surface of the microstructures is extracted and used In the microstructure processing apparatus using the FIB to process the pocket in the microstructure, FIB irradiation probe (probe) for irradiating the FIB to the microstructure; A section cutting unit for performing a section cut for reattachment thickness measurement; An image photographing unit photographing an image of a cross section for measuring the reattachment thickness; An image processor for measuring a reattachment thickness from the image photographed by the image capturing unit; A database storing processing related data; And a controller configured to control each of the components to calculate correction data of the machining error due to reattachment, and to perform a series of processes related to processing the microstructure.

The microstructure processing apparatus using the FIB may further include a monitor for providing pocket processing information including a magnified image of the reattached cross section and a thickness of the reattached surface.

The processing related data stored in the database may include the type of microstructure to be processed, shape data of a pocket, and processing error correction data.

The microstructure processing apparatus using the FIB further includes a data receiving unit for receiving the image information including the image file of the cutting section to be processed, the type of the microstructure to be processed, the shape data of the pocket, and the machining error correction data. can do.

The microstructure processing apparatus using the FIB may further include a stage position control unit for controlling the position of the FIB irradiation to the microstructure by controlling the position of the stage in which the microstructure is fixed when the microstructure is processed using the FIB.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

1 is a view showing a process of processing a microstructure using the FIB according to the present invention. Referring to the drawings, the probe 102 of the microstructure processing apparatus using the FIB to fabricate the pocket 104 in the microstructures 101.1, 101.2 to be processed to investigate the FIB (103.1 to 103.N) The process of doing this is shown.

Cross sections of the microstructure 101.1 before processing and the microstructure 101.2 after processing are shown. After the probe 102 irradiates the FIB 103.1 for a predetermined time and finishes the target FIB irradiation process, the probe 102 changes the irradiation direction of the FIB to irradiate the FIB 103.2 and finally irradiates the FIB 103.N in the N-th direction. Proceed to the process. The irradiation directions 103.1 to 103.N and the number N of irradiation directions are set before processing, and the amount of FIB irradiation in each irradiation direction is also set in advance according to the shape of the pocket 104 to be processed.

Small pockets are processed by adjusting the irradiation direction of the FIB as described above, but when the size of the pocket is large, the stage (not shown) which fixes the microstructure 101.2 is fixed while the irradiation direction of the FIB is constant. It can also process by a system.

FIG. 2 is a view showing a phenomenon in which the material removed by the irradiated FIB is reattached in a pocket processed in the microstructure when the microstructure is processed using the FIB according to the present invention.

In the probe 202 of the microstructure processing apparatus using the FIB, when the FIB 203 is irradiated onto the microstructure 201 to be processed, sputtering (sputtering) of the removed material occurs. Arrows 204 and 205 shown in dashed lines represent an example of the direction in which material is sputtered. Sputtering outside the processing microstructures (204) has no effect on machining the originally intended pocket shape, while sputtering into the processed pockets (205) re-attachs the removed material inside the processed pockets. Formation of layer 206 causes a shape that is distorted from the originally intended pocket shape.

FIG. 3 corrects this difference (hereinafter referred to as a machining error) from the shape distorted by the reattachment of the sputtered material and the intended shape of the pocket described above with reference to FIG. It is a figure which shows the calculation sequence of the processing error correction data which can process the intended pocket shape at once in consideration of the error.

First, the data 301 for the pocket shape to be processed is input 302. The input data is input to the FIB process to proceed the pocket processing 308 by FIB irradiation. After the primary processing, the measurement error measurement is started by cross-sectional analysis. To this end, first, a cross section cutting process 309 is performed. First, a material for protecting the cross section is filled into the processed pocket, and carbon may be used as such material. By filling the carbon, the reattachment shape can be detected by displaying the color contrast difference, that is, the contrast difference between the reattachment layer and the carbon deposited layer. After filling the carbon, the cross section is cut, and an image of the cut cross section is taken 310. The photographed section is input to the actual processing depth detection process 311 as an image file, and the actual processing depth detection process 311 detects the actual processing depth due to reattachment through image processing. The actual processing depth is input to the processing error calculation process 304 (303). The machining error is a difference between the distorted shape and the intended shape of the pocket as described above, which is the value of the intended pocket shape data 301, i.e., the pocket depth minus the actual machining depth, and this calculation is calculated. In step 304 it is performed. This processing error is finally inputted to the FIB processing process 308 again as a reattachment error, and repeats the processing error calculation process (307 to 311, 303, 304) by FIB processing and reattachment as described above. Of course, in this case, the target machining depth becomes the machining error, that is, the reattachment error (307) input into the FIB machining process 308, and the machining error is again within the allowable range because the machining error due to the reattachment occurs again. The processing error calculation process described above is repeated until it comes in. Meanwhile, the above-described processing error is always input to the error accumulation process 306 to generate a cumulative error. When the machining error is within the allowable range, the input 307 to the FIB machining process 308 and the input 305 to the error accumulation process 306 of the machining error are stopped, and the machining error accumulated up to now is processed. The error correction data calculation process 315 is input (313), and the intended pocket shape data 301 is also input to the processing error correction data calculation process 315 (314), and processed as a sum 315 of the two data. Error correction data is calculated and stored in the database 316. The processing error correction data is data that can be processed at one time in the shape of the pocket to be processed in consideration of reattachment, which will be described later with reference to FIG. 4.

4 is a diagram illustrating a process of calculating the machining error correction data described above with reference to FIG. 3 using a cross-sectional shape diagram of a pocket. 'I = 1' represents a pocket cross-sectional diagram 400 at the time of primary processing. is a pocket cross-sectional diagram 410 at the time of secondary processing, and "i = N" represents a pocket cross-sectional diagram 420 at the time of N-th machining. In the drawing 400 denoted by 'i = 1', 'K' in the originally intended pocket shape data 401 indicates one machining position of the pocket as one of positions at which the probe irradiates the FIB on the microstructure. All are described based on the 'K' point. 'A' refers to the bottom of the pocket. The original intended machining depth at point 'K' is 'C1', the depth of the pocket. The inclined surface of the pocket shape 402 after the primary processing is the surface by the redeposition described above, where R1 is the depth actually processed by the redeposition, and the processing error E1 is E1 = C0-R1. Means thickness. The drawing 403 which shows E1 below on the basis of the pocket bottom surface 'A' is shown, and E1 becomes the target processing depth for secondary processing mentioned later. Also shown is a diagram 404 showing the cumulative value S1 of the machining error beneath, based on the pocket bottom surface 'A'. 'W1' means reattachment width.

In the drawing 410 denoted by 'i = 2', the drawing 411 in which 'C2' is denoted is C1 of the originally intended pocket shape data 401, and the cumulative value S1 of the machining error in the aforementioned drawing 404 is added. It is a figure which shows the shape added to the pocket bottom surface "A" or less. That is, C2 is the data obtained by adding the cumulative error S1 after the primary processing to C1, which is the depth of the pocket, and is illustrated by the pocket cross-sectional diagram 411.

In the pocket cross-section diagram 412 after the secondary machining, the actual machined depth R2 was increased than R1, and the machining error E2 and the reattachment width W2 were smaller than E1 and W1, respectively. In other words, it can be seen that the overall reattachment thickness is reduced. A drawing 413 showing E2 below the pocket bottom is shown, where E2 is the target depth for tertiary machining. A drawing 414 is shown showing the cumulative value S2 of the machining error underneath the pocket bottom surface 'A'.

Thus, in the drawing 420 indicated by 'i = N' as the drawing after the processing for correcting N machining errors, the drawing 421 in which 'CN' is indicated is the first intended pocket shape data 401 and C1 until the previous time. The figure which shows the shape which added the cumulative value SN-1 of the processing error of less than or equal to the pocket bottom surface "A". CN is the final machining error correction data of the 'K' position. That is, after storing the data in a database, the same pocket machining on the same microstructures of the same material is performed after reading the machining error correction data CN from the database and processing the amount of FIB to the depth CN. The 'K' point is examined. Since this is data considering the error by reattachment as described above, the depth C1 of the originally intended pocket is processed after such processing. A drawing 421 showing the machining error correction data is shown for each machining position of this pocket as well as the 'K' position.

5 is a flowchart illustrating a process of calculating the above-described processing error correction data.

First, after positioning the microstructure to be processed on the stage and initializes the accumulated value of the machining error required to calculate the machining error correction data to 0 (S500). Thereafter, the FIB irradiation probe of the microstructure processing apparatus using the FIB is irradiated to the microstructure FIB for pocket processing (S502). As described above with reference to FIG. 1, in the case of a small pocket, the stage can be processed by adjusting the irradiation direction of the FIB. When the size of the pocket is large, the stage in which the microstructure is fixed is fixed while the irradiation direction of the FIB is constant. It can also be processed by the method to make it.

After that, the process of measuring the process error by reattachment is started (S504). As described above with reference to FIG. 2, a phenomenon in which some of the sputtered material is redeposited inside the processed pocket occurs, whereby the difference between the original shape of the pocket and the currently processed pocket Occurs. In this step, the processing error due to such reattachment is measured, which will be described later in detail with reference to FIG. 6. At this time, it is determined whether the processing error is within the allowable range (S506), and if it is not within the allowable range, the processing error just measured is added to the current processing error accumulated value (S508), and the FIB capable of processing only the processing error just measured. The pocket processing by irradiation is repeated (S502), and if the error is within the allowable range, the depth of the original intended pocket is added to the current machining error accumulated value and stored in the database as machining error correction data (S510).

FIG. 6 is a flowchart illustrating a processing error measurement process by reattachment described above with reference to FIG. 5.

First, as described above with reference to FIG. 5, the pocket is first processed by irradiating the microstructure with FIB (S600), and the surface protection material is filled in the inside of the first processed pocket to measure the processing error due to the reattachment. However, carbon may be used as the cross-sectional protection material (S602). It is then used to measure the reattachment thickness by the color contrast, ie, the contrast, between the carbon layer and the pocket layer in cross-sectional image analysis. The cross section is cut to measure the reattachment thickness (S604), and an image of the cross section is taken (S606). The target processing depth and the depth of the carbon layer, that is, the depth to the reattachment surface, are determined through the image processing on the photographed cross section (S608), and the processing error due to reattachment, that is, the thickness of the reattachment layer is calculated (S610). .

7 is a flowchart showing a pocket machining process to which machining error correction data is applied. 5 and 6 described above was a process of calculating the processing error correction data, this figure is a flow chart for processing the desired pocket shape at a time without a repeat loop by applying the calculated processing error correction data.

First, input the information of the microstructure and the pocket to be processed into the microstructure processing apparatus using the FIB (S700). Obviously, the machining error correction data for the microstructure and the pocket should already be calculated and stored in the database. The processing error correction data is extracted from the database (S702) and pocket processing according to the processing error correction data is performed (S704). As described above with reference to FIG. 4, the machining error correction data is data that is corrected to dig deeper than the depth according to the shape of the pocket to be processed in consideration of reattachment during machining. In other words, when the machining according to the processing error correction data, the reattachment phenomenon is considered, so that the shape of the original target pocket comes out at a time when the processing is completed.

8 is a view showing the internal structure of the microstructure processing apparatus 800 using the FIB. Referring to the drawings, the microstructure processing apparatus using the FIB according to the present invention includes a control unit 805, FIB irradiation probe 810, stage position control unit 815, cross-section cutting unit 820, image photographing unit 825, image The processor 830 includes a monitor 835, a data receiver 840, and a database 845.

The control unit 805 is responsible for calculating processing error correction data in FIB processing and a series of processes related to processing of the microstructure by controlling each component.

The FIB irradiation probe 810 is a device for irradiating an ion beam.

Since the stage position control unit 815 is difficult to precisely process only by adjusting the irradiation direction of the FIB when processing a relatively large pocket, the stage position control unit 815 is processed while moving the stage where the microstructure is fixed. to be.

The cross section cutout 820 fills the processed pocket with a material for protecting the cross section, for example, carbon, and serves to cut the cross section of the pocket in order to measure the reattachment error.

The image capturing unit 825 photographs a cross-sectional image of the pocket cut by the cross-sectional cutting unit 820, and allows the image processing unit 830 to measure a machining error, that is, reattachment thickness, as the image file.

As described above, the image processor 830 analyzes the cross-sectional image captured by the image capturing unit 825 to calculate the depth of the carbon layer, that is, the depth actually processed due to the reattachment, and then measure the reattachment thickness therefrom. do.

The monitor 835 is a device for displaying a series of processing-related data to the user, including the cross-sectional image as described above, the actual processed depth and reattachment thickness.

The data receiver 840 is a module that receives data input by a user. The data includes, for example, the type of the microstructure to be input or processed in the image file, the pocket-related data, and the like.

The database 845 is a device in which types of microstructures to be processed and processing error correction data according to the pocket shape to be processed are classified and stored.

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto and is intended by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

According to the present invention, the processing error correction data by reattachment is calculated through a control algorithm that accurately measures the reattached material shape using an image processing technique after FIB processing and performs FIB correction accordingly. In the future mass production, by FIB processing using the correction data, it is possible to efficiently process the microstructures of various materials in the intended precise shape, without the need to use expensive gas (gas).

Claims (10)

A microstructure processing apparatus using a focused ion beam (hereinafter referred to as FIB) is caused by reattachment of removed material, which occurs when processing a groove of a specific shape (hereinafter referred to as a pocket) on the surface of the microstructure. In a method of calculating data for correcting a machining error (hereinafter referred to as machining error correction data), (a) initializing the machining error accumulation value; (b) irradiating the microstructure with an amount of FIB that can be processed by the intended depth of the pocket (hereinafter referred to as pocket depth); (c) the depth from the surface of the material before processing (hereinafter referred to as the horizontal plane) to the surface of the material reattached into the pocket (hereinafter referred to as processing depth), and the value obtained by subtracting the processing depth from the pocket depth (hereinafter referred to as repositioning). Measuring an error); (d) If the reattachment error is within the set allowable range, proceed to step (e). If the reattachment error is not within the allowable range, add the reattachment error to the cumulative machining error value and then from step (b). Repeating the process; (e) storing a value obtained by adding the pocket depth to the cumulative machining error value for the microstructure as a machining error correction data in a database; Method for calculating the processing error correction data during FIB processing of the microstructure, characterized in that it comprises a. The method according to claim 1, Step (c) is, (c1) filling the pocket with a material for protecting the cut end of the pocket; (c2) cutting the cross section for measuring the reattachment error of the pocket; (c3) measuring the reattachment error of the pocket; Method for calculating machining error correction data during FIB processing of microstructures, characterized in that consisting of. The method according to claim 2, Measurement of the reattachment error of the pocket in the step (c3), (c31) taking an image of the cross section; (c32) detecting the processing depth by performing an image processing program on the image of the photographed section; (c33) determining the reattachment error of the pocket by subtracting the processing depth from the pocket depth; Method for calculating machining error correction data during FIB processing of microstructures, characterized in that consisting of. In the method for processing a pocket in the microstructure by applying the machining error correction data calculated in step (e) of claim 1 by the microstructure processing apparatus using FIB, (a) receiving information when the user inputs the microstructure and the pocket to be processed; (b) reading processing error correction data previously measured in the processing of the pocket from a database; (c) irradiating the microstructure with an amount of FIB capable of processing a depth corresponding to the processing error correction data; FIB processing method of the microstructure to which the processing error correction data, characterized in that it comprises a. The method according to claim 4, After step (c), (d) measuring a value obtained by subtracting the actually processed depth from the intended pocket depth (hereinafter referred to as reattachment error) and displaying the reattachment error on the monitor if the reattachment error is not within a predetermined allowable range; FIB processing method of the microstructure to which the processing error correction data, further comprising a. delete delete delete delete delete

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