JPS60136315A - Micro-ion beam processing method and equipment thereof - Google Patents

Abstract

PURPOSE:To prevent ununiform processing and enable obtaining a desired shape of processing by varying parameters which affect quantity of processing such as scanning repetition frequency, scanning speed, ion beam current, acceleration voltage in accordance with the shape of a processed portion, the shape after processed and the processed position. CONSTITUTION:In such a case as processing the Al wiring 30 on an SiO2 film 29, the intensity of beam current is varied in accordance with a position. In this case, in either method of scanning along the direction of wiring and gradually moving to the vertical direction or scanning conversely, ion beam current is made greater when the center of the wiring is irradiated by the ion beam. This makes near the end where easily removed by spattering on the side of a pattern is irradiated with smaller ion beam current and the center where not easily removed is irradiated with greater ion beam current whereby only Al is uniformly removed.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to micro ion beam processing in which a sample is processed by focusing an ion beam from a high-brightness ion source such as a liquid metal ion source into a narrow spot and irradiating it onto a sample. It is about the method.

[Background of the invention]

Figure vfJ1 shows a configuration diagram of an apparatus that performs microfabrication of a sample using a high-intensity ion source. All parts shown in FIG. 1 are housed in a vacuum container. Possible high-brightness ion sources include liquid metal ion sources such as Ga and ion sources with a capacitive structure that cools the chip to an extremely low temperature. I will now use the former as an example.

extracted from the liquid metal ion source 1 and applied to the electrode 2.
The ion beam 3 extracted by stone and pressure is 4,5.
Under the focusing action of an electrostatic lens consisting of the electrodes shown in 6,
While being deflected by the deflection electrode 10, the beam is irradiated onto the sample on the sample stage 13 and processed. Here, 11 is a stake meter electrode, which is a % pole for correcting and eliminating astigmatism of the ion beam. Further, reference numeral 8 denotes a flank electrode, which deflects the vinyl at a high speed of several MHz and moves it out of the aberration 9 so that it does not reach the sample, thereby performing beam switching (on/off operation). It is something.

FIG. 2 shows a method for processing a sample using this micro-ion beam. Now, assume that a rectangular region consisting of ABCD on the surface of the sample is to be processed. The ion beam is focused onto a minute spot 18 by the ion beam 7 shown in FIG. 1, and scanned in the direction of A→B using a deflection electrode. As a result, a processed groove 14 is formed. Similarly, using a deflection electrode, slightly downwardly machine the groove 14 and partially 1. 1- Form the processing groove so that it becomes the same.

The following steps 16, 17, etc. are performed to process the area AHCD.

Here, the following problem arises. In micro ion beam processing, processing is performed by a sputter link process. In other words, when an ion beam is incident on a sample, it slightly collides with atoms inside the sample (cascade scattering) and finally (some atoms are repelled from the sample surface).
It gets hit by a J and pops out, and is eliminated. In this case, for example, the cross section of VL and SL is shown in Figure 3. In this case, the following problem occurs.In other words, the 31st element 1 has a trapezoidal shape on the insulating film (supporting body) 19.
When removing a formed ug film with a micro ion beam, the primary incident ion beam is
If it is near the center of the AI wiring (Au thin film) as in Q
The sputter link atoms fly out only from the upper surface of the sample as shown in 22 and are removed. However, as shown in 23, the primary incident ion beam is
If present on the sides of the sample, the scattering cascade
1. Since it can be done close to the lj plane, it is possible to
Sputtered atoms protrude to the surface 1 as shown in the figure. Of course, sputtered atoms fly out from above as shown in 24.

As mentioned above, since the machining progresses from the 1II1J direction, the machining speed becomes slower in the center and repeats at a certain time.
After the scanning process, the removed shape resembles that of silk 4 and 1, with an unremoved portion 26 occurring in the center.

In addition, in order to remove this, if further processing is performed (repeat processing is performed), the part 26 that was in transit will be removed, or as shown in Fig. This results in a deeper processing than described above, which has an adverse effect.In the case of processing the Au thin film of the current Xi mask, polyimide II!i
I! Mechanical improvement of the support by processing it more than necessary
There is a decline in the degree. 5iU2 formed on a mature Si base
In the case of processing the A1 wiring on the insulating film, problems such as short circuits due to the processing of the lower part, effects on the lower wiring, the lower junction, and the gate part occur. As mentioned above, in the conventional micro ion beam processing method, there was a problem that a desired processed shape could not be obtained due to sputter linking from the side.

In addition, in a processed sample consisting of several bales of material, sputtering differs depending on the material, and as a result, only certain materials are processed, resulting in uneven processing, resulting in intermittent processing similar to the above. There were also problems. As shown in Fig. 10(a), when caroeing a composite forest material consisting of a portion of material A48 with a high sputter link rate and a portion of material B49 with a low sputter link rate with respect to the ion beam, this is done from above. When irradiating the ion beam uniformly, B is processed and becomes <<, A oB7. , the problem is that the machining progresses rapidly, resulting in uneven machining as shown in FIG. 10 (bl) and FIG. 10 (C).

[Purpose of the invention]

The purpose of the present invention is to eliminate the problems of the prior art, to suppress uneven machining caused by engraving of sputter links on the side surfaces, and differences in sputter link ratio due to negative printing, and to obtain a desired machined shape. An object of the present invention is to provide a micro ion beam processing method and an apparatus therefor.

[Summary of the invention]

In other words, the present invention adjusts the ion beam scanning method, the number of scanning repetitions, the number of scanning repetitions, the scanning speed, the ion beam current, the accelerating voltage, and the amount of processing depending on the shape of the part to be processed and the shape after processing. The present invention is a micro ion beam processing method in which a desired shape can be obtained by irradiating a sample while changing its parameters depending on the location of the sample. A means for measuring the quality of the material of the sample is also used, and the desired shape is obtained by irradiating the ion beam while changing each of the above parameters according to the determined results.

[Embodiments of the invention]

FIG. 6 shows an embodiment of the present invention. When processing the AI wiring 3o on the 8I0z film 29 with a cross section as shown in FIG. 6(a), the intensity of the first beam stream is set to 6](b)
Change depending on the location as shown in . In this case, when the sample is viewed from above, the sample is scanned in the direction along the wiring as shown in Figure 6(C), and then sequentially moved in the direction perpendicular to this (see Figure 6(d)). On the other hand, it is possible to omit the method of scanning in the opposite direction, but even if the central fils of the wiring is irradiated with the ion beam, the ion beam current becomes large. The parts near the edges are irradiated with a small ion beam current, while the center part is irradiated with a large ion beam current, Figure 6 (C)
As shown in Figure 3, it is possible to obtain the result that only AI is uniformly removed.

FIG. 7 also shows a similar example of removing AI wiring.

5 similar to Figure 6 (a), which is similar to Section 7 Section 1 (a)
i(J2)JQ 29 Upper cvh] When removing the wiring 3o using a micro ion beam, the number of ion beam scans is set to be large at the center of the wiring and small at both ends, as shown in Figure 7(b). For example, as shown in Fig. 7(C), when the immersion is carried out in one direction along the wiring and the removal is carried out by gently moving it in the direction perpendicular to this, this is true. The entire area is scanned and processed as shown in C). Next, as shown in Fig. 7(d), only the inside part is scanned and processed without scanning both sides, and then processed as shown in Fig. 7(e).
It could be realized by scanning and processing only the central part, as shown in the figure below.

Fig. 8 shows another embodiment of the "association" in which similar processing is performed, and the cross section of the same 6 as shown in Fig. 8 (a) is S t.
(When processing the A1 distribution 30 on the J2 insulating film 29, a secondary electron image etc. is imaged by scanning an ion beam (or a secondary electron image etc. is imaged by a separately provided electron beam scanning)
Detection of houses, etc. is performed using a separately installed beam.
The profile of the cross-sectional shape of the sample shown in FIG. Next, the ion beam is scanned and processed so that the distribution of the ion beam/electric ratio corresponding to this is shown in FIG. 8(b). In this case, = r The beam intensity distribution (Fig. 8(b) 8-) may be determined so that it is similar to
Figures 8(a) to 8(b) using the relationship:
i: decided y) is also acceptable. This ion beam irradiation causes the eighth
Figure (C1) There will be unremoved AI wiring, so
The cross-sectional shape is measured by a means for detecting a secondary image by scanning the ion beam. From this, the beam intensity distribution (FIG. 8(d)) is determined in a similar manner, and ion beam processing is performed based on this. As a result, a cross-sectional shape as shown in FIG. 8(e) is obtained, which is measured and irradiation is performed with a beam intensity distribution as shown in FIG. 8(f). By repeating this process, the machined cross-sectional shape is finally changed as shown in FIG. 8(g) in which only AI has been successfully removed. Head of this method P9t
It is also suitable for materials and samples with unknown processing characteristics such as sputter link characteristics, especially composite materials made of multiple materials.
The advantage is that good machining can be achieved by repeatedly performing machining and measurement over time.

In this example, FIG. 8 (bl, (dl,
(fl indicates the beam intensity distribution,
A similar process can also be performed to show the distribution of the number of repeated scans. In the examples at Imanuka, we have only described the A1 wiring on the Si0z insulating film as a processed sample, but the same can be said of other materials such as polyimide of an X-ray exposure mask or Au pattern on a BN support. Applicable to

Similar results can be obtained by changing the processing parameters such as the number of repeated processing, the ion beam intensity, and the ion beam acceleration pressure.

Figure 9 shows an apparatus for realizing the above embodiment.

The ion beam optical system and sample stage are in vacuum vessel 3 shown by dotted lines.
It is stored in 1. The liquid metal ion source 32 is heated by a heater power source, and the ion beam 42 is extracted by a potential difference between the liquid metal ion source 32 and the extraction power source 34 . A voltage is applied to the control 1iVf, 33 by the control power supply 33a, and by changing this control voltage, the ion beam current can be changed even when the extraction pressure is constant. The spot diameter and focal length of the ion beam can be changed by changing the voltage applied by the lens power source 35a to the middle electrode 35 of the three electrodes 34, 35, and 36 having a lens function. flanking electrode 37, flanking TL source 37a1, blanking aperture 38, stake meter electrode 40,
The role of stakemeter Hiroshi #, 408, etc. is the same as described above. The ion gun section consisting of a heater #t32a, a control #33a, and an extraction power source 34a is floated with respect to ground -1 by an acceleration power source 45, which serves as an acceleration voltage for the ion beam. The accelerated and focused ion beam is irradiated onto a sample 43 on a sample stage 44 . Here, the deflection-4 source 39a outputs a voltage of a toothed wave in the X direction and the Y direction, and the deflection electrode 39a
is applied to deflect the beam in X and Y directions. Then, a secondary cage image of the sample is displayed on the display by the input to the secondary electron detector 41 and the sharp tooth wave from the deflection "lH%j39a."

The above is a typical ion beam device and configuration, but the feature of this embodiment is that it is equipped with a CPU 46 that controls them. That is, to describe the case in which the embodiment shown in FIG. 8 is included, the CPU 1'! The control source 33a or extraction power source 3 generates the signal shown in FIG. 8(C) and changes the ion beam current accordingly.
While issuing a command to the ion beam 4a, the ion beam is deflected by the deflection point 39a to perform scanning processing. Machining result No. 8 again
The secondary of Figure (C) is made by spare No. 4m, No. 8 (D).
) is generated by the CPU 46. This is repeated below.

In the above example, when changing the current of the ion beam or changing the number of repetitions of scanning, the CPU 46 gives the command to the deflection power supply 39a, and changes the number of repetitions of scanning depending on the irradiation location. Do it like this. When changing the accelerating voltage (the energy of the ion beam), the CPU 46 sends a command to the accelerating power source 45 to change its output voltage as the beam scans. However, in this case, since changing the accelerating voltage changes the focal position of the beam, it is necessary to simultaneously send a command to the lens power source 35H and change the lens voltage to maintain the focal position unnecessarily.

In the above case, the CPU 46 stores the storage device 4 as necessary.
7 and exchange data. It is clear that the apparatus shown in FIG. 9 can be used in the same manner to perform the operations shown in FIGS. 6 and 7 in the same manner.

Although this is based on the detection of secondary electron images by
Detection may also be performed by making it possible to introduce it into the .

In the above embodiments, the shadow # of the cross-sectional shape of the sample, such as the cutting of wiring, was mainly described, but it is clear that the desired processing result can be changed by the same means even in the case of non-uniform processing of composite materials. In addition, if a 41-pole computational analysis tube or a distributed X-ray detector is used as a detector, changes in material depending on location can be detected.
Useful for composite materials.

〔Effect of the invention〕

As explained above, according to the present invention, the sample can be
When processing with an ion beam, it is possible to obtain a desired processed shape with LQt without the influence of sputter links on the side surfaces or the influence of non-uniformity of the material.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram (cross-sectional view) of a conventional processing device using a micro ion beam, Fig. 2 is an explanatory diagram (top view) showing scanning processing using a micro ion beam, Figs.
and Fig. 5 are cross-sectional views showing the conventional processing method using a micro ion beam and its results, Fig. 6, Fig. 7, and Fig. 8.
The figure is an explanatory diagram (cross-sectional view) showing the processing method according to the present invention,
Fig. 9 is a configuration diagram showing a processing device using a micro ion beam according to the present invention, and Fig. 10 is an explanatory diagram 31 showing the uneven progress of ion beam processing in the case of a temporary stand material, etc. in the conventional method.・Vacuum container 32...Liquid ring ion source 32a...Heater'..., Ryo 33...Control electrode: 33a...Control source 34, 35, 36...Electrode 34a River drawer' Power source 35a... ...Lens power supply 37...Flanking electrode 37a...Blanking' power supply 38...Blanking aperture 39...Deflection electrode 39a...Deflection' power supply 39b...
...Display 40...Stake meter pole 40a...Stake meter power supply 41...Secondary rod detector 43...Sample 44...Sample stage 45...Acceleration'#, Ryo 46... CPU47...
Akio Takahashi, Patent Attorney for Memory Devices Figure 1 Figure 2! 3 Figure 1000 Figure 1 Hangezu Figure 2 (C) (d) Figure 7 T7777D 6 Figure (C) (j) (f) Lightning 2 Figure 2 ( (t (C

Claims (1)

[Claims] 1. An ion beam from a high l 14 degree ion source such as a liquid gold high ion source is focused into a minute spot using electrostatic optics A, etc., and irradiated onto a test piece ''C, which is then processed. In Kamoai, more parts are scooped out for areas that are difficult to process, such as sputter links to the side of the sample and differences in sputter link rate depending on the quality, and the easier it is to process, the easier it is to see the snow. Micro ion beam processing is characterized in that the desired processed shape of L1 is obtained by irradiating the ion beam while changing the current, acceleration voltage, and number of repeated scans according to the irradiation jM n+ so that less processing is performed. Method. 2. Irradiate the above ion beam to generate secondary electrons f8+(
A trial cross-sectional profile is obtained from the scanned ion image), and this determines the ion beam current, acceleration chamber pressure, and number of repeated scans depending on the location on the sample, and the ion beam is irradiated and processed accordingly. The ion beam processing method according to claim 1, wherein a desired processed shape is finally obtained by repeating the process of obtaining a profile of the sample from the secondary electron image. 3. As a means of measuring the above-mentioned cross-sectional profile and particle size, irradiation with an electron beam, laser, or ordinary light and the resulting secondary electrons, reflected electrons, absorbed electron reflected light, scattered light, X-rays, secondary ions, etc. The micro ion beam processing method according to claim 2, characterized in that a method of measuring by receiving is used. 46 A high-intensity ion source such as a liquid metal ion source in a vacuum container, an extraction electrode for extracting the ion beam, a control electrode for controlling the beam current, a lens electrode for focusing the ion beam, and a lens electrode for deflecting the ion beam. A micro ion beam that is equipped with a deflection electrode and a sample stage, as well as a power source to drive these and an acceleration power source to accelerate the ion beam, and operates these to irradiate the sample with the ion beam and process it. The processing equipment is equipped with a CPtJ (Central Processing Unit) such as a mini-computer, and processes the measurement results of the sample profile based on the scanning ion image of the ion beam, etc. to determine the Ili! of the ion beam to be irradiated to each part of the sample. The distribution of parameters such as the degree distribution, the number of repeated scans distribution, and the ion acceleration voltage distribution is increased, and the output voltages of the control power supply, extraction power supply, deflection power supply, acceleration power supply, and lens power supply are changed accordingly with the deflection position. A micro ion beam processing device characterized in that it measures the sample profile, determines the parameter distribution, and performs ion beam irradiation processing (repeatedly) as necessary. 5. As a means for measuring the cross-sectional profile. , electron beam laser, irradiation with normal light, and a detector that receives and measures secondary radiation, reflected radiation, absorbed electrons, reflected light, scattered light, secondary ions, X-rays, etc. A micro ion beam processing apparatus according to claim 4, characterized in that the micro ion beam processing apparatus is configured as follows.