JP2002331500A - Alignment marker and alignment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alignment marker and an alignment method of a simple structure and enabling extremely precise processing covering a wide range exceeding a fine movement area where high resolution can be provided. SOLUTION: This alignment marker and this alignment method are used for processing an article to be processed by relatively scanning a scanning type probe on the article to be processed according to a processing shape with a fine movement operation and a coarse movement operation. The alignment marker is created at a processing completion point in a processing area side processed with the fine movement operation and is constructed as a marker capable of detecting error of the coarse movement operation when the coarse movement operation is performed to exceed the range of the fine movement operation and to overlap on an adjacent fine movement operation area based on an error amount assumed for the coarse movement operation. A processing starting point after the coarse movement operation can be found by detecting the marker.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an alignment marker and an alignment method used when processing a workpiece using the principle of a scanning probe microscope (SPM).

[0002]

2. Description of the Related Art In recent years, a scanning tunneling microscope (hereinafter abbreviated as STM) capable of directly observing the electronic structure of a conductor has been developed [G. Binnig et al. Phys. Re
v. Lett, 49, 57 (1982)]
Microscope devices that obtain various information and their distribution by scanning a probe with a sharp tip, such as M (atomic force microscope), SCaM (scanning capacitance microscope), and NSOM (near-field optical microscope), are being developed one after another. It has been. Currently, these microscope groups are scanning probe microscopes (SP
M), which has been widely used as a means for observing microstructures having resolution at the atomic and molecular levels.

Further, using the principle and apparatus configuration, a voltage is applied between the tip of the probe and the sample (workpiece) to perform anodic oxidation, and the probe is pressed against the sample to perform cutting. Since it is possible to process with a precision close to the measurement resolution by a method such as exposing a resist using an NSOM probe with an aperture, it is possible to process structures such as quantum effect devices that are less than the processing limit of photolithography, such as several nm to 100 nm. Its application is expected as a processing means.

[0004] For example, Japanese Patent Application Laid-Open No. 9-172213 proposes an electronic device having a fine structure manufactured by locally modifying a conductive region using a scanning tunneling microscope. Also, Japanese Unexamined Patent Publication No. 6-09
No. 6,714, proposes a surface micromachining apparatus for processing a sample surface by making a probe surface of a scanning probe microscope conductive and applying a voltage between the probe tip and the sample surface. Also, JP-A-10-34070
No. 0 proposes a cutting method for processing a sample surface by relatively moving the probe and the sample surface while the probe supported by an elastic body is in contact with the sample surface.

[0005]

By the way, these SPs
In the M system, the resolution in the direction of the sample surface is determined by the operation accuracy of the scanning mechanism that performs measurement and processing scanning. To achieve high resolution, these scanning mechanisms use a mechanism that combines a piezoelectric element, a voice coil, and an elastic hinge. Is used. Since these mechanisms operate within the limit of elastic deformation, the scanning range is generally very small, within about 100 μm × 100 μm.
For this reason, it has been a cause that it is not possible to meet the demands for high-precision observation and processing in a wide range of several mm.

To solve these problems, see, for example,
Japanese Patent Application Publication No. 00-266770 discloses a method of performing scanning using static pressure guide and slide guide in order to perform measurement scan in a wide range. However, in the above-mentioned guide system, it is difficult to secure the measurement resolution at the time of wide-range measurement as a result of a reduction in controllability due to a decrease in the resonance frequency due to an increase in the size of the scanning mechanism and a problem of vibration during scanning.

Further, in Japanese Patent Application Laid-Open No. 2000-206024, measurement scanning is performed by an xy scanning mechanism having a mechanical structure,
An arrangement is shown in which an error such as backlash during scanning is removed using a guide reference plane and a fine movement mechanism in the z direction. However, the decrease in controllability due to the enlargement of the scanning mechanism is as described above. In addition to the complicated device configuration, there is a problem that the creation and maintenance of a high-precision and wide-range guide reference plane causes an increase in cost. I have.

Therefore, the present invention solves the above-mentioned problems, and provides an alignment marker and a simple structure which enable processing with high accuracy over a wide range beyond a fine movement region which is a region for achieving high resolution. It is an object of the present invention to provide an alignment method.

[0009]

SUMMARY OF THE INVENTION The present invention provides an alignment marker and an alignment method configured as described in the following (1) to (12) in order to achieve the above object. (1) An alignment marker used for processing a workpiece by relatively scanning a probe of a scanning probe on a workpiece according to a processing shape by a fine movement operation and a coarse movement operation, and processing the workpiece. The marker is created at the processing end point on the processing region side processed by the fine movement operation, and based on the error amount assumed at the time of the coarse movement operation, a fine movement region adjacent beyond the range of the fine movement operation is determined. An alignment characterized by being configured as a marker capable of detecting an error of the coarse motion when the coarse motion is performed so as to be overlapped, and a processing start point after the coarse motion being obtained by detecting the marker. marker. (2) The alignment marker according to (1), wherein the alignment marker has a linear shape having an angle different from the processed shape. (3) The alignment marker according to the above (1) or (2), wherein the alignment marker at the processing end point is constituted by a plurality of alignment markers. (4) The alignment marker according to (3), wherein the plurality of alignment markers are configured such that an intersection of an extension of the alignment marker indicates a processing end point. (5) The alignment marker according to any one of (1) to (4), wherein the plurality of alignment markers are formed separately from the processed shape. (6) The alignment marker according to any one of (1) to (5), wherein the alignment marker is configured to be created or detectable by using the scanning probe. (7) Alignment for creating or detecting an alignment marker used when processing the workpiece by relatively scanning the probe of the scanning probe over the workpiece according to the processing shape by fine movement operation and coarse movement operation. A method, wherein an alignment marker used in the alignment method is created at a processing end point on a processing region side processed by the fine movement operation, and based on an error amount assumed during the coarse movement operation, It is configured as a marker capable of detecting an error in the coarse movement operation when performing the coarse movement operation so that adjacent fine movement regions overlap each other beyond the range of the fine movement operation, and the marker after the coarse movement operation is detected by detecting the marker. An alignment method, wherein a processing start point is obtained. (8) The alignment method according to the above (7), wherein a linear alignment marker having an angle different from the processing shape is created or detected, and the workpiece is processed. (9) As an alignment marker at the processing end point,
The alignment method according to the above (7) or (8), wherein a plurality of alignment markers are created or detected to process the workpiece. (10) An intersection of the extension lines of the plurality of alignment markers is created so as to indicate a machining end point, or a machining end point is detected from the intersection of the extension lines of the plurality of alignment markers, and machining of the workpiece is performed. The alignment method according to the above (9), which is performed. (11) The alignment method according to any one of (7) to (10), wherein an alignment marker having a shape isolated from the processed shape is created or detected, and the workpiece is processed. (12) The alignment method according to any one of (7) to (11), wherein the creation or detection of the alignment marker is performed using the scanning probe.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In an embodiment of the present invention,
By applying the above configuration, the sample is processed by relative scanning on the sample with the probe, and after coarse movement, the relative marker is again scanned on the sample and the sample is continuously processed to continuously process the sample. Alternatively, in the alignment method, the processing may be continued by configuring the alignment marker to indicate the processing end point before the coarse movement. Thus, when processing is performed by combining a coarse movement mechanism having a relatively low precision compared with the SPM resolution and a high precision fine movement mechanism conventionally used as a scanning mechanism of the SPM, the coarse movement error detection indicating the processing end point is performed. Create a marker for, based on the amount of error assumed during the coarse movement operation, perform a coarse movement operation so that adjacent fine movement areas overlap, detect the marker to determine the processing start point, based on the result By performing the machining operation after the coarse movement operation, it is possible to create a large-scale machining pattern exceeding the fine movement region with a simple configuration. Further, since this marker has an angle different from the processing shape, marker detection after the coarse movement operation becomes easy. Further, since the intersection of the extension lines indicates the processing end point, the detection is easy and accurate. Furthermore, since it is isolated from the processed shape, it has little effect on, for example, the electrical characteristics of the processed shape. Furthermore, since the creation and detection of the marker are performed using the processing probe itself, the device configuration is simplified.

[0011]

Embodiments of the present invention will be described below.
First, a processing apparatus configured by applying the present invention and its operation will be described. As shown in FIG. 1, a probe 111 including an elastic body 109 having conductivity and a probe 110 is
It is arranged so as to face the surface of the sample 112. Sample 1
12 is attached to the xyz fine movement stage 107, and x
The yz fine movement stage 107 includes an xyz coarse movement stage 108.
Attached to.

The processing control circuit 101 for instructing the scanning amount is:
The scanning control amount is output to the fine movement control circuit 102 according to the processing pattern and the scanning speed prepared in advance. The fine movement control circuit 102 controls the xyz fine movement stage 107 in accordance with the instructed control amount, and relatively scans the probe 110 and the sample 112. The operating range of the xyz fine movement stage 107 is x
100 μm × 100 μm in y plane, 20 μm in z direction
It is. During scanning, the voltage application circuit 113
In accordance with the instruction from 01, a voltage is applied between the probe 110 and the sample 112 to process the surface of the sample 112.

The coarse movement control circuit 103 receives a command from the machining control circuit 101 and receives an instruction from the xyz coarse movement stage 108.
Control. The operating range of the xyz coarse movement stage 108 is x
200mm x 200mm in y plane, 50mm in z direction
It is. In this embodiment, as an example of the sample 112,
An object in which a Ti thin film is formed on a Si wafer by sputtering is used.

This is attached to the apparatus shown in FIG. 1, voltage is applied, TiOx is generated by anodic oxidation, and a raised insulating portion is formed. The processing pattern can be appropriately determined to a desired shape. However, for the sake of explanation, in the present embodiment, a case where a linear processing pattern 206 having a length exceeding the fine movement range is processed as shown in FIG. 2 will be described. . First, when the processing has progressed to the end of the first fine movement area, an alignment marker 401 as shown in FIG. This marker has two upper and lower linear shapes having an inclination of 60 degrees with respect to the linear processing pattern 206, and does not intersect with the processing pattern 206 so as to be electrically independent from the processing pattern 206. , And the extension lines intersect at the processing end point. The length of the marker is 1 μm, and the positional relationship between the processing end point of the alignment marker 401 and the processing end point of the processing pattern 206 is 50 nm apart in the x direction in FIG.

Next, when processing a linear processing pattern 206 having a length exceeding the fine movement range shown in FIG.
The probe 110 and the sample 112 are moved by the xyz coarse movement stage 108 in the first direction in the x direction as shown in the coarse movement operation 208.
Relatively move beyond the fine movement region 201 of the first position. Then the second
Of the probe locus 2 in the fine movement region 202 of FIG.
As indicated by 07, using the xyz fine movement stage 107, the processing returns to the end point of the processing in the first fine movement range, a voltage is applied to the sample 112, and the processing is continued. By repeating this, a linear processing pattern 206 extending from the first fine movement region to the fifth fine movement region is formed.

Hereinafter, the movement between the fine movement regions using the coarse movement mechanism will be described in detail with reference to FIG. 3, taking the movement from the first fine movement region to the second fine movement region as an example. First, the operation amount of the coarse movement operation 208 was determined as follows. From the previously measured values, x in the figure of xyz coarse movement stage 108
Positioning error when moving in the x direction is ± 0.5 max.
It is known that the maximum is ± 1.5 μm in the μm and y directions. A margin is added to the error amount in the x direction, and the adjacent fine movement region is 2 μm.
The operation is performed 98 μm in the x direction so that m overlaps, that is, at the time of the coarse movement operation 208. FIG. 3 shows a second fine movement region as an ideal second fine movement region 301 when the coarse movement operation 208 is performed without error.

To protect the probe 110, the processing control circuit 10
1 issues a command to the fine movement control circuit 102, and sufficiently separates the probe 110 and the sample 112 using the xyz fine movement stage 107. At this time, the control amount is set to 10 μm in view of safety because the amplitude in the z direction during the coarse movement is known to be 3 μm at maximum from the measured value. After the probe 110 and the sample 112 are separated from each other, the processing control circuit 101 issues a command to the coarse movement control circuit 103, and moves the probe 110 in the x direction using the xyz coarse movement stage 108 by the above-described coarse movement operation amount of 98 μm. Move relative.

Next, after the probe 110 and the sample 112 are brought into contact with each other, a surface measurement operation for detecting a coarse movement error is performed.
The size of the measurement area is set to 2 μm in the x direction and 4 μm in the y direction by adding a margin to the error amount.
Is performed, a point that should be a machining end point in the first fine movement area is ± 1 μm in the x direction and ± 2 μm in the y direction.
μm. The processing control circuit 101 issues a command to the fine movement control circuit 102, and scans the measurement area in a raster using the xyz fine movement stage 107. Displacement sensor 11
Reference numeral 5 denotes a four-division photodiode which receives reflected light of laser light emitted from the laser 114 to the elastic body 109, converts the reflected light into an electric signal, and outputs the electric signal to the displacement detection circuit 104. The displacement detection circuit 104 detects the input electric signal as the displacement amount of the probe 110 and outputs it to the imaging circuit 105, where the control signal (scanning position data) from the fine movement control circuit 102
Then, the image is formed as a surface shape on the sample 112 and sent to the position error detection circuit 106. From the obtained surface shape image data, the marker shape is detected by the position error detection circuit 106, and the intersection of these extended lines is obtained, thereby calculating the processing end point in the first fine movement area and the processing start point To the processing control circuit 101. The processing control circuit 101 moves the probe 110 to the processing start point by using the xyz fine movement stage 108, and restarts the processing.

In this embodiment, an optical lever system is used to detect the displacement of the probe 110. However, other displacement detecting means such as a capacitance system may be used. Also,
In this embodiment, an application example of an anodic oxidation method is particularly shown. However, the present invention is also applicable to a processing apparatus using another processing method such as cutting and chemomechanical effects.

[0020]

As described above, according to the present invention, it is possible to perform processing with high accuracy over a wide range beyond the fine movement region, which is a region for achieving high resolution, with a simple configuration. An alignment marker and an alignment method can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a device configuration in an embodiment of the present invention.

FIG. 2 is a diagram for explaining a processing operation in the embodiment of the present invention.

FIG. 3 is a diagram for explaining an alignment operation in the embodiment of the present invention.

FIG. 4 is a diagram for explaining an example of an alignment marker according to the embodiment of the present invention.

[Explanation of symbols]

 101: machining control circuit 102: fine movement control circuit 103: coarse movement control circuit 104: displacement detection circuit 105: imaging circuit 106: position error detection circuit 107: xyz fine movement stage 108: xyz coarse movement stage 109: elastic body 110: search Needle 111: Probe 112: Sample 113: Voltage application circuit 114: Laser 115: Displacement sensor 201: First fine movement area 202: Second fine movement area 203: Third fine movement area 204: Fourth fine movement area 205: Second 5 fine movement area 206: processing pattern 207: probe trajectory 208: coarse movement 301: ideal second fine movement area 401: alignment marker 402: extension of alignment marker

Claims (12)

[Claims] An alignment marker used for processing a workpiece by relatively scanning a probe of a scanning probe on a workpiece according to a processing shape by a fine movement operation and a coarse movement operation, The alignment marker is created at a processing end point on a processing region side processed by the fine movement operation,
A marker capable of detecting an error of the coarse motion when the coarse motion is performed such that adjacent fine motion regions overlap each other beyond the range of the fine motion based on an error amount assumed at the time of the coarse motion. Wherein a processing start point after the coarse movement operation is obtained by detecting the marker. 2. The alignment marker according to claim 1, wherein the alignment marker has a linear shape having an angle different from the processed shape. 3. The alignment marker according to claim 1, wherein the alignment marker at the processing end point comprises a plurality of alignment markers. 4. The alignment marker according to claim 3, wherein the plurality of alignment markers are configured such that an intersection of an extension of the alignment marker indicates a processing end point. 5. The alignment marker according to claim 1, wherein the plurality of alignment markers are formed separately from the processed shape. 6. The alignment marker according to claim 1, wherein the alignment marker is formed or detectable by using the scanning probe. 7. A probe of a scanning probe is relatively scanned by a fine movement operation and a coarse movement operation on a workpiece according to a processing shape to create or detect an alignment marker used when processing the workpiece. An alignment method, wherein an alignment marker used in the alignment method is created at a processing end point on a processing region side processed by the fine movement operation, and based on an error amount assumed during the coarse movement operation. A marker for detecting an error in the coarse motion when the coarse motion is performed so that adjacent fine motion regions overlap with each other beyond the range of the fine motion, and the coarse motion is detected by detecting the marker. An alignment method, wherein a later processing start point is obtained. 8. The alignment method according to claim 7, wherein a linear alignment marker having an angle different from the processing shape is created or detected, and the workpiece is processed. 9. The alignment method according to claim 7, wherein a plurality of alignment markers are created or detected as the alignment marker at the processing end point, and the workpiece is processed. 10. The method according to claim 1, wherein an intersection of the extension lines of the plurality of alignment markers is formed so as to indicate a machining end point, or a machining end point is detected from the intersection of the extension lines of the plurality of alignment markers. 10. The alignment method according to claim 9, wherein processing is performed. 11. The alignment method according to claim 7, wherein an alignment marker having a shape isolated from the processed shape is created or detected, and the workpiece is processed. . 12. The alignment method according to claim 7, wherein the creation or detection of the alignment marker is performed using the scanning probe.