JP2000323083A - Projection type ion beam machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve projection ion beam(PJIB) machining, focusing ion beam(FIB) machining and FIB observation with high accuracy in a high throughput even if the shape of an opening pattern of a mask or the height of a sample is varied by monitoring the opening pattern. SOLUTION: An ion source 1, a first electrostatic lens 2, a first electrostatic deflector 4, a mask 14, a second electrostatic deflector 5, a second electrostatic lens 7 and a sample 8 are arranged in this order. The deflection center in the case where the first and second electrostatic deflectors 4, 5 are interlocked therebetween is set near the center of the second electrostatic lens 7. Furthermore, a beam limiting diaphragm 12 is interposed between the ion source 1 and the first electrostatic deflector 4. With this optical system, the opening pattern of the mask 14 can be monitored. Moreover, a sample height measuring device and an XYZ driving sample stage 9 are provided, thereby achieving a desired projection reducing rate and a desired beam state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion beam processing apparatus, and more particularly to a processing apparatus for locally processing an electronic component such as a semiconductor by using a projection ion beam. It relates to a processing device.

[0002]

2. Description of the Related Art As a technique for locally processing an electronic component such as a semiconductor, a focused ion beam (Focused Ion Beam;
IB) An FIB processing technique utilizing a sputtering phenomenon caused by irradiation is known, and is applied to processing and observation of a cross-section at a desired position of a semiconductor element or the like, and correction of wiring. The device is called a FIB device. FIB
Are focused so that an ion beam emitted from the ion source is imaged by the electrostatic lens system on the sample. The diameter of the focused beam is determined mainly by the amount of image blur due to aberration of the electrostatic lens system because the image of the ion source is small, and its size is practically 10 nm to several μm. The beam current ranges from several pA to 10 nA. When the beam current reaches several nA, the beam diameter increases rapidly due to the spherical aberration of the lens system, and the current density decreases. The processing speed increases as the beam current increases, while the beam processing accuracy increases as the beam diameter decreases. Therefore, the processing speed and the beam processing accuracy have a reciprocal relationship. Therefore, high machining accuracy F
IB has a low beam current and a low processing speed.

Recently, a projection ion beam has been used as an ion beam that satisfies both the high processing accuracy and the high processing speed.
(Projection Ion Beam; PJIB) was proposed. The device is called a PJIB device.
And Japanese Patent Application Laid-Open No. H10-1626969.

FIG. 18 is a schematic diagram of the apparatus shown in
Reference is made to FIG. The ion beam 63 emitted from the ion source 51 irradiates a mask 56 having a pattern opening in which a desired processing shape is enlarged by a first electrostatic lens 54, and the beam 6 having passed through the pattern opening
3 is a projection beam by the second electrostatic lens 57 and reaches the sample 59. At this time, the image of the pattern opening is reduced and projected on the sample 59 by the second electrostatic lens 57, and is processed into a desired processing shape. This projection pattern image has large distortion and blur at the peripheral portion away from the optical axis as disclosed in Japanese Patent Application Laid-Open No. 9-162098.
It has a very sharp feature near the axis. Therefore, in the case of processing requiring high processing accuracy only in the vicinity of the axis, PJIB having a large beam current is much more advantageous than FIB even if the current density is low.

Japanese Patent Application Laid-Open No. 9-186138 discloses a PJIB apparatus capable of forming an FIB. The FIB is used for observing a sample in a PJIB processing portion. This observation, PJ
It is effective for adjusting IB processing conditions and confirming the optimum condition.

[0006] In a PJIB apparatus in which the opening pattern of the mask itself corresponds to a processing pattern, the deformation of the opening pattern due to sputtering damage is periodically monitored. It needs to be replaced with an opening pattern. Here, regarding the replacement of the opening pattern, it is important to arrange the opening pattern on the optical axis from the viewpoint of processing accuracy. If the shape of the necessary portion of the opening pattern is relatively large, the projection processing pattern size is effectively made the same by slightly reducing the projection reduction ratio.
The life of the opening pattern can be extended.

However, conventional PJIB devices (for example, JP-A-9-162098 and JP-A-10-162696) disclose a method of monitoring the deformation of the aperture pattern and an ion optical system incorporating necessary optical components. It has not been.

Further, there is a need in PJIB processing applications that a plurality of samples having different heights are individually arranged and mounted together on a sample stage, and these are processed at the same projection reduction ratio.

However, although the conventional PJIB apparatus discloses that the height position of the sample surface must always be constant in order to always perform the sample processing at a constant projection reduction ratio, this processing needs to be performed. No specific means for responding to the request is disclosed. In other words, in this processing application of the PJIB device,
It has been found that some kind of sample height measuring means is necessary. On the other hand, in the FIB processing apparatus, the processing size is determined by the setting of the beam scanning area, so that the same size processing can be performed even if the sample height is different. Therefore, F
There is no necessity for the sample height measuring means in the IB device.

The means for measuring the height of the sample is used in an electron beam measuring machine, and is disclosed, for example, in Japanese Patent Application Laid-Open No. 8-273575. When a sample is irradiated with a laser beam obliquely, the position of the laser beam reflected by the sample and detected by the position sensor changes according to the height of the sample. Thus, the height of the sample is measured by measuring the change in the position of the reflected laser beam using a position sensor. By feeding back the measured value to the objective lens and adjusting the lens strength, it has been possible to avoid defocusing of the electron beam and to improve the throughput of the length measuring operation.

However, since the electron beam length measuring device does not need to keep the lens magnification constant, there is no need to keep the sample height constant.

[0012]

The object of the present invention is to solve the following four problems.

(A) A PJ for which a method of monitoring the deformation of an opening pattern of a mask and an optical component necessary for the method have not been established.
Provided is a PJIB apparatus which can monitor the shape and deformation of an opening pattern of a mask due to sputtering damage with a simple operation, compared to the IB apparatus. (B) The PJIB that can always perform high-precision projection processing by adjusting the projection reduction ratio to effectively change the projection processing pattern size to the deformation in which the shape of a necessary portion of the mask opening pattern relatively changes. Provide equipment.

Further, the projection reduction ratio is adjusted for the deformation in which the shape of a necessary portion of the mask opening pattern relatively changes, so that the size of the projection processing pattern is made to be effectively the same and the life of the opening pattern is extended. PJ that can
An IB device is provided.

(C) When the sample height changes for each processing position or for each sample, a PJIB apparatus capable of adjusting the projection reduction ratio to effectively make the projection processing pattern size the same and always performing high precision projection processing is provided. provide.

(D) In addition to the PJIB, a PIB is formed on the PJIB apparatus described in (a) to (c) above, so that PJIB processing, FIB processing, and FIB observation can be performed with high precision and high throughput. I will provide a.

[0017]

A PJIB apparatus according to the present invention comprises an ion source, a first electrostatic lens, a first electrostatic deflector, a mask, and a second electrostatic device in order from the ion source to the sample. Deflection center of combined beam scanning when the deflector, the second electrostatic lens, and the sample are arranged and the first electrostatic deflector and the second electrostatic deflector are simultaneously operated. Is located approximately at the lens center of the second electrostatic lens, and a beam limiting aperture for limiting the emission angle of the emitted ions is located between the ion source and the first electrostatic deflector. The optical system is characterized in that: The above problems (a) and (b) can be solved because the shape and deformation of the opening pattern of the mask can be easily monitored by the mask observation image by the optical system.

Further, the PJIB apparatus according to the present invention comprises a light source section for irradiating a light beam obliquely to the sample surface and a light detecting section for receiving the light beam reflected on the sample surface and detecting the light receiving position. And a means for measuring the height of the sample, wherein the irradiation light beam and the reflected light beam are arranged between the second electrostatic lens and the sample. When the mask projection rate is specified, the sample height has a specified value. If the measured value from the sample height measuring means deviates from the specific value, in order to eliminate this deviation, a sample stage (XYZ) having a driving mechanism in the sample height direction, that is, the Z direction is used. Moving). On the other hand, if the mask projection magnification is not specified, the beam control unit calculates both the optimum lens application voltage for PJIB and FIB based on the measurement value from the sample height measurement unit. This sample height measuring means is particularly suitable for the above problems (c) and
It is important to solve (d).

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a schematic structural view of a two-stage lens system PJIB processing apparatus of the present invention. From the ion source 1 to the sample 8 side, a first electrostatic lens 2 as an optical element, a beam limiting aperture 12 for limiting the emission angle of emitted ions, a blanking deflector 3, a first one-stage electrostatic deflector 4, a blanking plate 16, a mask 14, a second one-stage electrostatic deflector 5,
The two-stage electrostatic deflector 6, the second electrostatic lens 7, and the sample 8 are arranged in this order. These optical elements are connected to the beam control unit 17, and a PJIB mode or a FIB mode can be selected. Secondary particles (secondary electrons, secondary ions, etc.) 10 are emitted from the sample 8 by the beam irradiation, and are detected by the secondary electron detector 11. The sample 8 is mounted on a sample stage 9 that can move in XYZ. These optical elements and the sample stage 9 are placed in a vacuum vessel 19 connected to an exhaust pump (not shown). The optical element is connected to the beam control unit 17, and a window screen and a scanning ion microscope (Sc.
Processing preparation and processing work are performed using a CRT 18 that displays an image screen of an anion ion microscope (SIM). FIG.
Shows a beam when the PJIB mode is selected. The first electrostatic lens 2 has an ion emission point of the ion source 1 as an object point, and its image point is substantially the second electrostatic lens 7.
Is controlled to be located at On the other hand, the second electrostatic lens 7 is controlled such that the projected image of the opening pattern of the mask 14 is located on the sample 8. The beam limiting aperture 12 is connected to the drive unit 13 and has a large aperture 21 for PJIB processing.
a or a small opening 21b for adjustment can be brought on the optical axis. The mask 14 is also connected to the drive unit 15, and when the mask has one or more openings, the specific opening can be positioned on the optical axis. In this example in which the second electrostatic lens 7 is a three-electrode lens having the same electrode potential at both ends, the projection reduction magnification of the mask is:
The distance from the second electrostatic lens 7 to the sample 8 is set to a mask 14.
From the distance to the second electrostatic lens 7, which is 1/50 in this example. Here, in order to minimize the image blur of the projection pattern image (corresponding to the edge blur of the processed pattern), it is important to accurately align the opening of the mask 14 on the optical axis.

Next, a method of accurately aligning the opening of the mask 14 on the optical axis will be described with reference to FIG.

(A) Mask aperture and beam limiting aperture 1
2, the large opening 21a for PJIB processing is approximately aligned on the optical axis, and the ion beam 20 is deflected and scanned by the first-stage electrostatic deflector 4 to detect secondary electrons emitted from the sample. An image 1 is formed. However, the lens strength of the second electrostatic lens 7 is zero. The beam scanning range is set so that the SIM image 1 is circularly bright only at the center as shown in FIG. The peripheral dark portion of the SIM image 1 corresponds to a shadow of an electrode of the second electrostatic lens 7 or the like.

(B) In the SIM image 1 described above, the lens intensity of the first electrostatic lens 2 is controlled to make the unevenness of the sample surface clear, and the optimum lens intensity 1 is obtained. At this time,
The ions emitted from the ion source 1 are substantially focused on the position of the sample 8.

(C) When the lens strength of the first electrostatic lens 2 is swung back and forth within a narrow range from the optimum lens strength 1 of (b) by the wobbling function, a bright portion in the SIM image 1 is synchronized with the wobble. Although it moves, the ion source is finely adjusted in the XY plane (a plane perpendicular to the Z axis of the optical axis) so that the movement of the image is minimized, and the large opening 21a for PJIB processing is also rough in the XY plane. adjust. After the adjustment, the ion source position is fixed.

(D) The aperture of the beam limiting aperture 12 is set to PJI
Large opening 21a for B processing to small opening 2 for adjustment
Instead of 1b, the lens strength of the first electrostatic lens 2 is moved before and after the optimum lens strength 1 by the wobbler function as in (c), and a small aperture is set so that the movement of a bright portion in the SIM image 1 is minimized. 21b is finely adjusted in the XY plane.

(E) However, this bright portion is not always at the center of the SIM image 1. The aligner voltage is superimposed on the scanning voltage of the first single-stage electrostatic deflector 4 so that this bright portion comes to the center of the image. Thus, the ion source, the first electrostatic lens 2, the small opening 21a, and the second electrostatic lens 7 are on the optical axis. The position of the small opening 21a is registered and stored in the beam adjustment condition list of the beam controller 17 together with the aligner voltage and the optimum lens strength of the first electrostatic lens 2.

(F) Next, in addition to the first single-stage electrostatic deflector 4, the second single-stage electrostatic deflector 5 is also turned on, and the beam is largely scanned so as to include the mask opening. . However,
The deflection voltage of the second electrostatic deflector 5 is synchronized with the deflection voltage of the first electrostatic deflector 4 by shifting the phase by 180 degrees. The combined beam deflection center is located at the center of the second electrostatic lens 7 (see FIG. 4, but the beam focusing state corresponds to (j) described later). Thus, when the beam is scanned over a wide area on the mask, even if the scanning beam immediately after passing through the mask is emitted so as to be far away from the optical axis, it is returned to the optical axis direction by the second electrostatic deflector 5. The SIM image 2 at this time is a pattern image in which the opening of the mask becomes bright, but the edge of the opening pattern is blurred.

(G) To sharpen this image blur, the first
Of the electrostatic lens 2 is gradually increased, and the focal point of the ion beam 20 is shifted from the current sample 8 onto the mask 1.
Move up 4. When the beam focus point is exactly on the mask 17, the edge image of the mask aperture pattern is sharpest.

(H) Next, while keeping the aligner voltage of the first one-stage electrostatic deflector 4, the scanning voltages of the first and second one-stage electrostatic deflectors 4 and 5 are changed. Off and instead 2
The SIM image 3 is observed by turning on the stage-structure electrostatic deflector 6 (see FIG. 5). The beam deflection center of the two-stage electrostatic deflector 6 is located at the lens center of the second electrostatic lens 7. SIM
The image 3 is a surface image of the sample 8 but is not sharp because the beam spreads on the sample (provided that the beam passes through the mask opening at the aligner voltage). When the lens strength of the second electrostatic lens 7 is gradually increased, the beam is gradually focused on the sample, and the SIM image 3
Becomes clearer. The sharpest lens intensity is registered and stored in the PJIB processing condition list of the beam controller 17.
At this time, the beam reaching the sample is a beam emitted from the ion source 1 focused on the sample, and is not PJIB but FIB.

(I) The lens strength of the second electrostatic lens 7 is swung before and after the sharp image condition obtained in (h) (wobble function) so that the sample image in the SIM image 3 does not move. Fine adjustment of the aligner voltage of the electrostatic deflector 4 having the single-stage configuration of 1. The aligner voltage in the beam adjustment condition list of the beam controller 17 which has already been registered and stored is replaced with the adjusted voltage.

(J) Return the beam scanning to the scanning mode of the first and second one-stage electrostatic deflectors 4 and 5 (while keeping the aligner voltage on) and observe the SIM image 2 (see FIG. 4). ). The mask 14 is finely adjusted via the mask driving unit 15 so that the mask opening pattern is located at the center of the image in this image. The position shift amount that could not be adjusted is registered and stored in the PJIB processing condition list of the beam control unit 17 together with the mask opening position. The pattern positional deviation of the PJIB processing due to the positional deviation of the mask opening is corrected by applying a correction deflection voltage in consideration of the projection reduction magnification to the two-stage electrostatic deflector 6.

The mask opening pattern image of the SIM image 2 in (j) is clear, and the shape and absolute dimensions of the opening pattern can be understood. Thereby, deformation and dimensional change due to sputtering damage of the mask opening pattern during long-time operation can be observed. Also, if the absolute size of the mask opening pattern is known, even if this size slightly deviates from the design value, the second
By controlling the distance between the electrostatic lens and the sample surface, the projection magnification can be changed, so that pattern processing of a desired size can be performed. However, it is necessary to change the lens strength of the second electrostatic lens according to the change in the projection magnification.

In the embodiment shown in FIG. 1, the beam limiting aperture 12 is located between the first electrostatic lens 2 and the first electrostatic deflector 4, but the beam limiting aperture 12 is located at the first electrostatic lens 2. Since this is for controlling the resolution of the scan image using the deflector 4,
What is necessary is just to be between the ion source 1 and the first electrostatic deflector 4.
Although it can be placed between the ion source 1 and the first electrostatic lens 2,
When placed here, the distance between the ion source 1 and the first electrostatic lens 2 is widened, and as a result, the current density of PJIB is reduced, so that it is not very advantageous.

Blanking deflector 3 and blanking plate 1
Numeral 6 has a function of preventing the mask 14 from being irradiated with the ion beam 20 except for processing or observation in order to prevent the mask 14 from being damaged by ion sputtering.
Specifically, the ion beam 20 is emitted by the blanking deflector 3.
Is controlled so that the irradiation position of the ion beam 20 is on the blanking plate 16.

FIG. 6 shows an example of a beam focusing state in the PJIB and FIB modes in the two-stage lens system PJIB apparatus shown in FIG.
Shown in FIG. 7 shows a representative graph of the relationship between the processing edge blur of the pattern processing and the beam current in PJIB and FIB. Since the processing speed is almost proportional to the beam current, a large current beam is desirable from the viewpoint of high-speed processing. In the FIB processing, the FIB diameter is changed within a range of 10 to 2000 nm, and the processing edge blur at that time is almost equal to the beam diameter.
On the other hand, the beam diameter of the PJIB processing corresponds to the processing pattern size, and from the relation of the projection reduction ratio, the size is 0.1 to 10
Suitable for μm pattern processing. However, the processing edge blur is about 0.02 μm until the pattern size reaches several μm, and then increases sharply. In addition, from the viewpoint of the alignment accuracy of the processing position, when the alignment is performed using the SIM image, a small beam diameter that increases the resolution of the image is desirable. Therefore, in order to realize processing that satisfies all of high-precision positioning, high-speed processing, and reduction of processing-edge blur, processing positioning is performed using a FIB with a beam diameter of 10 nm, and then high-speed processing and processing-edge blur are performed. It is sufficient to switch to PJIB that satisfies both of the reductions. This device is
It is a device that has achieved this, and its effects have been confirmed experimentally.

A second embodiment will be described with reference to FIG. In this example, the second electrostatic lens has a configuration of two-stage lenses 7a and 7b, and is a PJIB device having a total of three-stage lenses. The feature of the PJIB device with a three-stage lens configuration is
Compared with a PJIB apparatus having a stepped lens configuration, the projection lens can be reduced without increasing the optical length from the ion source to the sample. In this example, the projection lens reduction ratio M shown in FIG.
Is the same optical length as a PJIB device having a 1/50 two-stage lens configuration, and M = 1/100. The method of accurately aligning the opening of the mask 14 on the optical axis and the method of optical axis alignment are essentially the same as the two-stage lens configuration PJIB apparatus of FIG. In addition, the PJIB apparatus can also form an FIB, and can perform processing that satisfies all of high-accuracy alignment, high-speed processing, and reduction of processing edge blur.

The monitor observation of the opening pattern of the mask by this optical system is performed by forming a narrow ion beam converging on the mask by the first electrostatic lens and the beam limiting aperture, and converting the beam to the mask by the first deflector. The area including the pattern opening is scanned XY, and the deflected beam that has passed only through the opening is deflected by the second deflector so as to be directed to the approximate center position of the second electrostatic lens (reverse to the first deflector). Scanning electron microscope (Sca) obtained by detecting secondary electrons emitted from the sample surface by beam irradiation
nning Ion Microscope (SIM). This SIM image reflects the positional information on the presence or absence of the beam passage on the mask surface, that is, an image of a light-dark contrast representing the opening pattern shape of the mask. Accordingly, not only the shape of the opening pattern but also the absolute dimensions can be known, and the life of the opening pattern due to sputtering damage can be accurately and easily determined. Further, when the absolute size of the opening pattern slightly deviates from the design value, or when the shape of a necessary portion of the opening pattern relatively changes, the projection reduction ratio for realizing the pattern processing of the desired size is accurately determined. And it can be easily obtained.

Next, an embodiment of the height measuring means provided in the PJIB processing apparatus of the present invention will be described. FIG. 9 shows a sample height measuring unit installed between the second electrostatic lens 7 and the sample 8. The sample 8 is placed on the sample stage 9 and moves in the X and Y directions under irradiation of the ion beam 20 by the sample stage 9, and further moves in the height direction, that is, the Z direction. When the samples 8a, 8b, 8c having different heights are mounted, the heights of the respective samples are measured, and the applied voltage of the second electrostatic lens 7 or the height of the stage 9 is measured in accordance with the amount of change. By changing it, the ion beam 20 is adjusted so that the processing edge is not blurred. The light source unit 22 is fixed between the second electrostatic lens 7 and the sample 8b by a fixing mechanism 37, and the laser beam 24 emitted from the light source unit 22 passes between the second electrostatic lens 7 and the sample 8b. The sample 8b is irradiated therethrough. The laser beam 25 reflected by the sample 8b is incident on the light detection unit 23, and a change in the incident position on the light detection unit 23 is detected. The change in the height of the sample 8b detected in this way is fed back as data for correcting the focus of the second electrostatic lens 7 or for correcting the height of the stage 9. Since the PJIB and the FIB are focused based on this data, the sample is not irradiated with any ion beam, and as a result, damage to the sample and a change in characteristics due to the sputtering phenomenon do not occur.

FIG. 10 shows a sectional view of one embodiment. Second
A laser light emitting element 26 is provided between the electrostatic lens 7 and the sample 8.
Is fixed, and the laser beam 24 emitted from the light emitting element 26 passes between the second electrostatic lens 7 and the sample 8 to irradiate the sample 8. At this time, the laser beam 24 is focused on the sample 8 by the condenser lens 28. The laser beam 25 reflected by the sample 8 is focused and incident on the position sensor 27 by the condenser lens 29, and
A change in the position of incidence on 7 is detected. The change in height of the sample 8 detected in this way is fed back as data for correcting the focus of the second electrostatic lens 7 or for correcting the height of the stage 9. The laser light emitting element 26 and the condenser lens 28 and the position sensor 27 and the condenser lens 29 are fixed independently. The laser light emitting element 26 and the position sensor 27 are attached by screws or the like, so that the operator can adjust the optical axis direction or the visual field. The laser light emitting element 26, the position sensor 27, and the condenser lenses 28 and 29 can also be integrated.

In this embodiment, the second electrostatic lens 7, the sample 8, the stage 9, and the condenser lenses 28 and 29 are installed and fixed in a vacuum, and the laser light emitting element 26 and the position sensor 27 are vacuum sealed. Is fixed via the laser light emitting element 26 and the position sensor 27.
Can be installed in a vacuum, and either one of them can be installed in a vacuum. Further, the second electrostatic lens 7, the sample 8, and the stage 9 are set in a vacuum,
The condenser lenses 28 and 29 are fixed via a vacuum seal, and the laser light emitting element 26 and the position sensor 27 can be installed in the atmosphere. One of them is fixed via a vacuum seal and the laser beam diameter is fixed. It is also possible to install a condenser lens on the road in a vacuum.

FIG. 11 is a sectional view of an embodiment of the height measuring means different from that of FIG. The laser beam 24 emitted from the laser light emitting element 26 passes through a window 30 through which the laser beam passes, is reflected by a mirror 32, and
The sample 8 is focused on the sample 8 and passes between the second electrostatic lens 7 and the sample 8 to irradiate the sample 8. The laser beam 25 reflected by the sample 8 is focused by the condenser lens 29, reflected by the mirror 33, passes through the window 31 and is focused and incident on the position sensor 27.
A change in the incident position on the substrate is detected. The windows 30 and 31 are fixed via a vacuum seal, and the laser light emitting element 25 and the position sensor 27 are mounted in the atmosphere with screws or the like, so that the operator can adjust the optical axis direction or the field of view. FIG.
As shown in FIG. 2, the laser light emitting element 26 and the position sensor 27 are directly fixed to a vacuum container via a vacuum seal,
It is also possible to omit the windows 30 and 31 or to omit only one of them. The mirrors 32 and / or 33 are provided between the condenser lens 28 and the sample 8.
Or on the beam path between the condenser lens 29 and the sample 8. Further, it is also possible to install a plurality of condenser lenses on the beam path of the laser beam 24 and the laser beam 25 or on one of the beam paths. The number of mirrors can be further increased.

FIG. 13 is a sectional view of an embodiment in which a mirror 33 and a window 31 are provided on the path of the laser beam 25 reflected by the sample 8. FIG. 14 shows a laser light emitting device 2
Mirror 3 on the path of laser beam 24 emitted from
FIG. 2 is a cross-sectional view of an embodiment in which a window 2 and a window 30 are installed.
As described above, it is also possible to mix an optical path through a mirror or a window with an optical path not through.

FIG. 15 is a sectional view of an embodiment in which an optical microscope is further added to the height measuring means shown in any of FIGS. FIG. 15 shows a cross section orthogonal to the cross section shown in FIGS. 1 to 5 except for the sample 8 and the stage 9, and shows a laser light emitting element 26 and a position sensor 27.
Are not shown because they are located in the direction perpendicular to the plane of the paper.

The optical microscope 34 looks through a part of the sample 8 via the image mirror 36. The image magnified by the optical microscope 34 is converted into an electric signal by the solid-state imaging device 35 and displayed on a cathode ray tube (not shown). This optical image is used for confirming a processing position in the sample 8 at a low magnification, which is difficult to obtain with a scanning image by an ion beam.
The difference between the processing position by the ion beam 20 and the observation position by the optical microscope 34 is corrected by using the stage 9 after measuring the observation position difference in advance. The focus is adjusted by, for example, adjusting the height of the stage 9. In FIG. 15, one image mirror is provided, but a plurality of image mirrors may be provided. It is also possible to provide a window in front of the optical microscope and install the optical microscope in the atmosphere.

In this case, an optical image obtained by the optical microscope 34 can be used for adjusting the focus of the ion beam 20. That is, first, coarse adjustment is performed by moving the stage 9 up and down so that the resolution of the optical microscope image is maximized, and then the ion beam 20 is focused by the method using a laser beam shown in FIGS. To The focusing method using the obliquely incident laser beam and the position sensor has an advantage that the height change of the sample 8 at the incident position of the ion beam 20 can be measured with high accuracy, but the dynamic range is narrow, and thus the dynamic range is increased. When combined with a method utilizing the contrast of an optical image by a relatively wide optical microscope, the focusing operation at the start of processing becomes easy.

The PJIB device and the FIB device are different from the electron beam length measuring device in the mounting position of the secondary particle detector and are located beside the second electrostatic lens 7, so that the secondary particles are guided to the detector. Space must be secured. Also, for a sample that causes charge destruction, such as a magnetic head, it is necessary to attach a charge neutralizing gun and irradiate the sample with an electron beam simultaneously with the ion beam in order to neutralize the positive charge of ions. In order to perform ion-induced deposition or gas assisted etching, a nozzle for introducing a deposition gas or an etching gas to the sample 8 must be inserted. Therefore, it is necessary to provide a space between the second electrostatic lens 7 and the sample 8 so that these can be realized. A space is secured between the second electrostatic lens 7 and the sample 8, the optical path of the laser beam from the light emitting element through the sample to the position sensor, the secondary particles from the sample to the detector, and the path from the charge neutralizing gun to the sample. The laser light emitting element 26, the position sensor 27, the secondary particle detector, the charge neutralizing gun, and the gas introduction nozzle are placed horizontally without any intervening objects in each path of the electron beam and each gas from each nozzle to the sample. The embodiment shown in FIG. 10 in which the vacuum vessel 19 is provided with an inclined portion is effective for attaching to the vacuum vessel 19 vertically, that is, at an arbitrary angle between 0 ° and 90 °. This mounting method is also effective in reducing the number of components because there are no such inclusions.

In the embodiment shown in FIG. 10, a laser light emitting element 26, a position sensor 27, a secondary particle detector, a charge neutralizing gun, a gas introduction nozzle for deposition, and a gas for gas assisted etching are provided on the inclined portion of the vacuum vessel 19. Six of the nozzles must be implemented and may interfere with each other in the vacuum vessel. In order to avoid such interference and facilitate mounting, the number of windows 30, windows 31, mirrors 32, mirrors 33, etc. increases, but the laser light emitting element 26 and the position sensor 27 are moved from the inclined portion of the vacuum vessel 19 to the horizontal portion. The embodiment of FIG. 11 and FIG.

Further, as shown in FIG. 16, it is possible to eliminate the inclined portion of the vacuum vessel 19 and mount the vacuum vessel 19 entirely on a horizontal portion.

FIG. 17 is a sectional view of an embodiment of the PJIB apparatus. The PJIB apparatus includes a mirror 37, a housing 39, and a vacuum pump 38 attached to the mirror 37. Here, the weight of the mirror portion 37 is offset to one side by the vacuum pump 38, and the vacuum pump 38 side must be separately supported by a column or the like. The support portion 40 is
The parts connected with may need to be reinforced to support the weight. When the housing wall in contact with the support portion 40 is thickened and reinforced as shown in FIG. 17, the inclined portion of the vacuum vessel 19 may decrease. In this case, interference of the laser light emitting element 26, the position sensor 27, the secondary particle detector, the charge neutralizing gun, the gas introduction nozzle for deposition, and the gas introduction nozzle for gas assisted etching in the vacuum vessel 19 is prevented. 13 and 14 are effective for mounting with additional windows and mirrors. For easier mounting, the embodiments of FIGS. 11 and 12 are effective.

In addition to the height measuring method using a laser beam shown in FIGS. 10 to 14, a capacitance sensor is installed around the optical axis of the ion beam 20 so as to face the sample 8, and the distance between the sensor and the sample 8 is increased. It is also possible to measure the volume of the sample and measure the sample height from the difference between the measured volumes.

There are the following two apparatuses / methods for realizing pattern processing of a desired size, that is, processing at a specific projection reduction ratio. The first apparatus / method is a two-lens optical system.
In this case, a PJIB device is used. Similarly, the sample height in the processing area is measured. From the projection reduction rate that realizes pattern processing of the desired dimensions, calculate the sample height that can obtain this projection reduction rate, find the difference from the sample height in the measured processing area, and calculate the height movement amount of the sample stage. Ask. A desired projection reduction ratio is realized by moving the sample height by the Z drive mechanism of the sample stage by this moving amount.

Further, the voltage applied to the electrostatic lens at which the edge of the PJIB becomes sharpest from the height of the sample after moving so as to achieve the desired projection reduction ratio and the voltage applied to the electrostatic lens at which the FIB is in focus are adjusted. The applied voltage is obtained by calculation or experiment and stored in a computer.

Thus, pattern processing of a desired size can be realized with high accuracy, and the mask life can be further extended. Furthermore, the operator does not need to adjust the electrostatic lens while scanning the ion beam on the sample and observing the image, and the ion irradiation may damage the sample,
There is no danger that the characteristics of the sample will change due to the ions being implanted on the sample. Also, PJIB and FIB
Can be performed simultaneously without scanning the ion beam on the sample.

The second device is a three-lens optical system PJI in which the second electrostatic lens is composed of two stages of electrostatic lenses.
This is the case of the device B. First, the sample height is detected by the sample height detecting means. When the sample height is not changed, the sample height is known, and the second two-stage static satisfies both the conditions of the projection reduction ratio for realizing the pattern processing of the desired dimensions and the sharpness of the edge of the PJIB processing pattern. The two voltages applied to the electric lens are obtained by a computer in the beam control unit 17 and stored. When the sample height can be changed, the sample height that satisfies the same conditions and the two voltages applied to the second two-stage electrostatic lens are also used as a variable by the computer in the beam control unit 17 as variables. Ask and memorize. FIB
Can be calculated in the same manner as the PJIB lens voltage regardless of whether the sample height has moved or not, and this is also stored. Thereby, CR
PJIB and FIB on T can be easily selected with the mouse from the display window.

[0055]

As described above, the PJIB apparatus of the present invention has a new optical system in which optical components necessary for monitoring the shape and deformation of the mask opening pattern by a simple operation are provided. Because you can observe
Its shape and absolute dimensions can be easily monitored.

Further, by providing a height measuring means in addition to the new optical system, it is possible to know the change in the shape of the mask opening pattern and the accurate sample height at the processing position. Thus, the desired projection reduction ratio can be easily and accurately adjusted, and even if the shape of the mask changes, the projection processing pattern size is effectively made the same and processing as set can be performed with high accuracy. As a result, the life of the opening pattern can be extended.

Further, in addition to the new optical system and the height measuring means, a sample stage having a driving mechanism in the height direction, ie, the Z direction, in addition to a mechanism for driving in the X and Y directions is provided. Even in a two-lens optical PJIB system, the projection reduction ratio can be changed by adjusting the sample height, so that the desired projection reduction ratio can be easily and accurately adjusted according to the current mask opening pattern, and the mask shape Even if the size changes, the projection processing pattern size is made the same effectively, and processing as set can be performed with high accuracy. As a result, the life of the opening pattern can be extended.

Further, according to the effect of the present invention, in addition to realizing a desired projection reduction ratio, optimal application to the electrostatic lens in both PJIB and FIB from the sample height data at the approximate area of the projection processing. Since the voltage can be obtained at the same time, PJIB processing, FIB processing, and observation can be realized with high precision and high throughput as a production processing apparatus represented by, for example, narrow track processing of a magnetic head.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a projection ion beam (PJIB) processing apparatus having a two-stage lens configuration according to the present invention.

FIG. 2 is an explanatory view showing optical axis alignment and axis alignment of a mask opening of the PJIB processing apparatus of FIG. 1;

FIG. 3 is an explanatory view showing optical axis alignment and axis alignment of a mask opening of the PJIB processing apparatus of FIG. 1;

FIG. 4 is an explanatory view showing optical axis alignment and axis alignment of a mask opening of the PJIB processing apparatus of FIG. 1;

FIG. 5 is an explanatory view showing optical axis alignment and axis alignment of a mask opening of the PJIB processing apparatus of FIG. 1;

FIG. 6 is an explanatory diagram showing two beam states of the PJIB processing apparatus.

FIG. 7 is a representative graph showing a relationship between a processing edge blur of pattern processing and a beam current in PJIB and FIB.

FIG. 8 is an overall configuration diagram showing a projection ion beam (PJIB) processing apparatus having a three-stage lens configuration according to the present invention.

FIG. 9 is a configuration diagram showing a sample height measuring unit installed between the second electrostatic lens and the sample of the PJIB processing apparatus of the present invention.

FIG. 10 is a cross-sectional view showing one embodiment of a sample height measuring unit installed between the second electrostatic lens and the sample of the PJIB processing apparatus of the present invention.

FIG. 11 is a cross-sectional view showing one embodiment of a sample height measuring unit installed between the second electrostatic lens and the sample of the PJIB processing apparatus of the present invention.

FIG. 12 is a cross-sectional view showing one embodiment of a sample height measuring unit installed between the second electrostatic lens and the sample of the PJIB processing apparatus of the present invention.

FIG. 13 is a cross-sectional view showing one embodiment of a sample height measuring unit installed between the second electrostatic lens and the sample of the PJIB processing apparatus of the present invention.

FIG. 14 is a cross-sectional view showing one embodiment of a sample height measuring unit installed between the second electrostatic lens and the sample of the PJIB processing apparatus of the present invention.

FIG. 15 is a cross-sectional view showing one embodiment of a sample height measuring unit installed between the second electrostatic lens and the sample of the PJIB processing apparatus of the present invention.

FIG. 16 is a cross-sectional view showing one embodiment of a sample height measuring unit installed between the second electrostatic lens and the sample of the PJIB processing apparatus of the present invention.

FIG. 17 is a sectional view showing an embodiment of the PJIB processing apparatus of the present invention.

FIG. 18 is a schematic view showing a conventional PJIB processing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ion source, 2 ... 1st electrostatic lens, 3 ... Blanking deflector, 4 ... 1st one stage electrostatic deflector, 5 ... 2nd
, A two-stage electrostatic deflector, 6...
... second electrostatic lens, 8,59 ... sample, 9 ... sample stage, 10 ... secondary particles (secondary electrons and secondary ions, etc.), 1
DESCRIPTION OF SYMBOLS 1 ... Secondary electron detector, 12 ... Beam limiting aperture, 13, 1
5: drive unit, 14: mask, 16: blanking plate, 1
7: Beam control unit, 18: CRT, 19: Vacuum container, 2
0, 63: ion beam, 21a: large aperture for PJIB processing, 21b: small aperture for adjustment, 22: light source section, 23: light detection section, 24: emitted laser beam,
25: reflected laser beam, 26: laser light emitting element, 27: position sensor, 28, 29: condensing lens, 37: fixing mechanism, 51: ion source, 54: first electrostatic lens, 56: mask, 57 ... Second electrostatic lens.

Continuation of the front page (72) Inventor Yuichi Madokoro 1-280 Higashi-Koigakubo, Kokubunji-shi, Tokyo F-term in Central Research Laboratory, Hitachi, Ltd. 5C033 BB01 BB02 BB09 5C034 AA02 AA03 AA09 AB03 AB05

Claims (6)

[Claims] 1. A sample is processed by collecting ions emitted from an ion source with a first electrostatic lens and irradiating the mask with an opening pattern of the mask onto the sample by a second electrostatic lens. In the projection type ion beam processing apparatus, the first electrostatic lens, the first electrostatic deflector, the mask, the second electrostatic deflector, and the second electrostatic lens are sequentially arranged from the ion source to the sample. And the deflection center of the combined beam scanning when the first electrostatic deflector and the second electrostatic deflector are operated in combination at the same time, and the second electrostatic lens And a beam limiting aperture for limiting an emission angle of the emitted ions is located between the ion source and the first electrostatic deflector. Ion beam processing equipment. 2. The projection type ion beam processing apparatus according to claim 1, wherein said second electrostatic lens comprises a two-stage electrostatic lens. 3. A focused ion beam for positioning an image of said ion source on said sample by controlling lens intensities of said first electrostatic lens and said second electrostatic lens. The projection type ion beam processing apparatus according to claim 1 or 2, wherein: 4. The projection type ion beam processing apparatus according to claim 1, further comprising means for measuring a height of the sample at an approximate region position in the projection processing of the sample. 5. A light source unit for irradiating the sample surface with a light beam obliquely from the sample surface, and a light detection unit for receiving the light beam reflected on the sample surface and detecting the light receiving position. 5. The projection type ion beam processing apparatus according to claim 4, wherein the irradiation light beam and the reflected light beam are disposed between the second electrostatic lens and the sample. 6. The apparatus according to claim 1, further comprising a sample stage having a mechanism for driving the sample in the X and Y directions and a mechanism for driving the sample in the height direction, that is, the Z direction. The projection ion beam processing apparatus according to claim 1.