JPH01124856A - Method for correcting defect of mask - Google Patents

Abstract

PURPOSE:To correct a black defect with high accuracy by focusing the ion beam from a high-illuminance ion source to a micro spot by a charge particle optical system then by projecting said beam to the black defect of a mask while preventing the disturbance of the spot, thereby removing the defect. CONSTITUTION:A mask sample 90 having the black defect is imposed on a sample base 60 in an exchange chamber 41 and is then put into a sample chamber 40 where the sample is imposed on a base 55. The inside of the chamber 40 is evacuated by a vacuum system to a vacuum and a high-voltage power supply 82 and a control device 85 are operated to impress voltages to respective electrodes by a power supply 77 for filament of a liquid metal ion source 65, an electrode power supply 78, an ion beam electrode source 79, and a deflecting electrode power supply 84. The sample 90 is first scanned by an ion beam spot 68' of several 10kV or below and is macro-displayed on a cathode ray tube 88. Then, an operator observes the black defect. In succession a negative voltage of several 10kV is impressed to the sample and the ion beam spot 68' is projected to the black defect. The black defect of the mask is corrected with the high accuracy by such constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for correcting defects in masks for semiconductor integrated circuits.

[Conventional technology]

In recent years, semiconductor integrated circuits (ICs) have become significantly smaller and more highly integrated, and the wiring pattern dimensions are moving from 3μ to 2μ, and it is predicted that 1° to 1°5μ patterns will be realized in a few years. There is. Along with this, advanced technology is also required for repairing defects that occur in masks. FIGS. 1 and 2 show a longitudinal section and a plane of the photomask. The photomask shown in these figures is made of O2 on a glass substrate 1.
A thin film (approximately 100 to 1,000 layers thick) of a material with low transmittance to exposure light, such as a metal material such as iron oxide or a metal compound material such as iron oxide, is deposited, and a desired wiring pattern is formed using photoetching technology. (hereinafter abbreviated as pattern) 3 is formed.

In FIG. 1, A is the interval between the patterns, and B is the width of the patterns. In such a photomask, black dot defects 4 and 5 and white dot defects 6 usually occur during a pattern forming process or the like. This is mainly due to the presence of foreign matter during the photoetching process. In this example, the black spot defects 4 and 5 are present in places where gold H and Cr' should not originally exist. The white spot defect 6 is a defect in which metal Cr is missing at a location where it should originally exist. If a photomask with such defects is used as is, these defects will be directly transferred to the element pattern on the wafer, resulting in defective ICs. Among the two types of defects, the number of black spot defects is larger than 4.5, and laser processing is currently the mainstream method for repairing this defect.

FIG. 3 schematically shows a conventional laser mask repair apparatus.

In this prior art, a laser beam 9 emitted from a laser oscillator 8 is reflected by a reflecting mirror 10, and a semi-transmissive mirror 1
1, the light is focused by a lens 12 and transferred to the fine movement stage 1.
A black spot defect 15 on a photomask 14 placed on 3
is irradiated to remove the black spot defect 15. Half mirror 1
6. An illumination optical system consisting of an illumination light source 17, a concave mirror 18, and a condenser lens 19 is for illuminating the sample surface. Further, the observation optical system consisting of lenses 20 and 21 observes the sample, moves the fine movement stage 13 to adjust the position of the sunspot defect 15, and the focused laser beam 9' is directed to the sunspot defect 15. This ensures accurate irradiation.

[Problem that the invention seeks to solve]

By the way, in order to correct the 3μ pattern wiring, the degree of correction, that is, the dimensional accuracy of the part removed during correction, is required to be ±1μ, which requires a focused laser spot diameter of 1μ or less. . This can be satisfactorily handled by using a short wavelength laser.

However, there is a lower limit to the miniaturization of the spot diameter by a laser beam due to the diffraction limit, and the limit is considered to be about 0.5 μm. This is the limit of laser focusing, and shows that mask modification techniques using laser processing cannot handle finer patterns.
For ICs with 1 to 1.5μ patterns and smaller wiring.

Mask defects of 0.3 to 0.5 μ or more are considered defects, and the minimum correction unit is required to be smaller than this. However, due to the focusing limit as mentioned above.

It can be seen that conventional laser processing technology cannot cope with this problem.

The above description is about modification of a photomask for exposure using visible and ultraviolet light. As patterns become finer, precise microfabrication cannot be achieved with photoetching technology that uses light that has problems such as single diffraction and scattering, so exposure using X-rays that have low single diffraction and scattering, or parallel beam ion beams will become more and more difficult. It is thought that it will be used.

An example of an X-ray exposure mask is shown in FIGS. 4(1) to 4(5).

First, as shown in FIG. 4(1), a parylene layer 24 with a thickness of several microns is formed on a Si substrate 23 with a thickness of several hundred microns, and a Cr thin film 25 with a thickness of several hundred microns is further formed on top of the parylene 24. An Au thin film 26 with a thickness of several thousand layers is formed thereon as an X-ray absorber. On top of this, PM is further thickened to about 1000 people.
Apply MA resist 27. Next, a necessary pattern is drawn and exposed on this using an electron beam exposure machine, and a development process is performed to form grooves 28 and 29 in the PMMA resist 27 as shown in FIG. 4(2). .

Using the grooves 28 and 29 formed in the PMMA resist 27, a Cr30 pattern with a thickness of 1000 mm is formed by the refo-off method as shown in FIG. 4(3). That is, in the water droplet state shown in FIG.
If the resist 27 is treated with a stripping solution and stripped, it becomes PMMA.
The Cr on the resist 27 is removed together with the PMMA resist 27, resulting in a pattern of Cr30.

After this, ion beam etching is performed as a thin film resist of this Cr30, and Au26 is removed in the part where there is no Cr30.
The thin film shown in FIG. 4 (4) is formed by removing the thin film.

Furthermore, the Si substrate 23 is largely etched from the back side,
By leaving only the parts necessary for support, the fourth
As shown in Figure (5), there is a thin film of about 1000 Au26, which absorbs X-rays, only in the necessary parts, and a thin film of about 1000 Cr30, which does not absorb X-rays, and parylene 2.
An X-ray resist is fabricated, leaving only the SL 4 and supported by the support portion 23' of the SL.

Next, FIG. 5 shows an example of a mask for exposure using a collimated ion beam.

The mask shown in FIG. 5 is composed of a support film 31, an ion absorber 32, and a spacer 33.

The support film 31 is made of a material that minimizes scattering of the ion beam that passes through it as much as possible. For example, it is a single crystal silicon thin film with the crystal axis in the vertical direction,
This means that when irradiating a collimated ion beam from above and below, if the direction of incidence of the ion beam matches the direction of the crystal axis of the Si support film, the inner part of the incident ion beam will pass through due to channeling, and the ions will be scattered. takes advantage of the fact that there are very few. In another example, a very thin, stiff material support membrane is used. For example, AQ with a thickness of several hundred to several thousand people stretched in a Pyrex mold.
, O, which allows ion beam A to pass through.

A thin film of, for example, Au is formed as the ion absorber 32 under the support film 31, and a pattern is formed on this thin film. The method is similar to that of an X-ray mask, and involves drawing of a resist such as PMMA by electron beam exposure, and accompanying etching.

The masks for X-ray exposure and collimated ion beam exposure have been described above.

These masks also require exposure and development of a resist such as PMMA, and it is inevitable that defects will occur due to foreign matter during this process.

Although X-ray exposure and ion beam exposure are expected to be applied to patterns of 1 μm or less, defects exist even in these masks, and correction accuracy of 0.2 μm or less is required. On the contrary.

It is clear from what has been stated above that correction by laser processing is not applicable.゛An object of the present invention is to eliminate the drawbacks of the above-mentioned conventional techniques, and to eliminate the problems that occur in photomasks, X-ray exposure masks, ion beam exposure masks, etc. for producing ICs with patterns of 1 to 1.5μ or 1μ or less. It is an object of the present invention to provide a method for correcting defects in a mask, which can correct defects in a mask with high precision and sufficient practical productivity.

[Means for solving problems]

In order to achieve the above object, the present invention extracts an ion beam from a high-intensity ion source such as a liquid metal ion source or a field ion source that operates at an extremely low temperature, and uses a charged particle optical system to generate an ion beam. This method of repairing defects in a mask is characterized in that the beam is focused on a minute spot and irradiated onto a black spot defect of a mask as a sample to remove the black spot defect. According to another aspect of the present invention, in the mask defect repair method, the ion beam is irradiated onto the black spot defect of the mask while preventing the spot from being disturbed by the charge of the ion beam using a charge neutralizing means.

[Effect]

With the above configuration, the ion beam can be finely focused with energy that can remove black spot defects on the mask.
To remove and correct black spot defects on a mask with high accuracy and with sufficient practical productivity without affecting circuit patterns of 1 to 1.5 μm or less than 1 μm.

Furthermore, since the charge of the ion beam is prevented from being accumulated on the mask, the ion beam spot is prevented from being disturbed, and black spot defects on the mask can be removed and corrected with even higher precision.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 6 shows an embodiment of a mask defect correction apparatus according to the present invention.

The apparatus shown in FIG. 6 includes a pedestal 37, a lens barrel 39 and a sample chamber 4o constituting a vacuum container, a sample exchange chamber 41 connected to the sample chamber 4o, an evacuation system, and a mounting mask for a sample. Table 65, liquid metal ion source 65, control (bias) electrode 66, ion beam extraction electrode 67, Avatia 69. Electrostatic lenses 70, 71, 72. Blanking electrode 73° Avatia 74. Deflection electrodes 75, 76, filament power supply 77, control electrode power supply 78, extraction electrode power supply 79, electrostatic lens power supply 80°81, high voltage power supply 82, blanking electrode power supply 83. Deflection electrode power source 84, power source control device [85, secondary charged particle detector 86 inserted into the sample chamber 40, SIM (scanning ion microscope) wt detector 87゜ Spot disturbance due to ion beam charge. 89.

The pedestal 37 is earthquake-proofed by an air support 38.

The sample chamber 40 and the sample exchange chamber 41 are connected to the pedestal 37.
A lens barrel 39 is installed above the sample chamber 40 .

The sample chamber 40 and the lens barrel 39 are partitioned off by a gate valve 43, and the sample chamber 40 and the sample exchange chamber 41 are partitioned off by another gate valve 43.

The vacuum exhaust system includes an oil rotary pump 47° and an oil trap 48. Ion pump 49, turbo molecular pump 5
0, valves 51, 52, 53, and 54. This evacuation system, the lens barrel 39, the sample chamber 40,
It is connected to the sample exchange chamber 41 via vacuum pipes 44, 45, 46, and these lens barrels 39. The sample chamber 40 and the sample exchange chamber 41 can be made to have a vacuum of 10'torr or less.

The document table 55 is provided with micrometers 56, 57 that move in the x, y, and z directions via rotation introduction terminals 61, 62, and 63.
．． 58 is attached, and a moving ring 59 in the θ direction is provided, and the stage 55 can be moved in
Fine movements in direction and angle of rotation in the horizontal plane are adjusted.

A sample stand 60 is installed on the document stand 55, and a mask as a sample is placed on the sample stand 60. The sample stage 60 can be moved between the sample chamber 40 and the sample exchange chamber 41 by a sample drawer 64, and when exchanging the sample, the gate valve 43 is opened, the sample stage 60 is pulled out into the sample chamber 40, and the gate Close the valve 43, open the door of the sample exchange chamber 41, exchange and place the sample,
After the door is closed and the sample exchange chamber 41 is preliminary evacuated, the gate valve 43 is opened and the sample stage 60 is placed into the sample chamber 40. In addition, in FIG. 6, the sample is indicated by the reference numeral 90.

The liquid metal ion source 65 is provided at the head of the lens barrel 39, facing the sample chamber 40. The liquid metal ion source 65 shown in FIG. 7 includes a base 650 made of an insulator, filaments 651 and 652 attached to the base 650 in a mold, and both filaments 651 and 652 made of tungsten or the like. It is configured to include a sharp needle 653 attached between the tip portions by spot welding or the like, and a metal 654 serving as an ion source attached to the needle 653. The metal 654 serving as an ion source is Ga.
, In, Au, Bi, Sn, Cu, etc. are used. Further, the filaments 651, 652 are connected to the electrodes 651'
, 652' as shown in FIG.
The filament power source 77 is connected to the filament power source 77 connected to the filament power source 77 .

The control electrode 66 is installed below the liquid metal ion source 65 and is connected to a control electrode power source 78 that is connected to a high voltage power source 82, and a low positive and negative voltage is applied to the installation position of the control electrode 66. and control the current of the ion beam.

The ion beam extraction electrode 67 is installed below the control electrode 66 and is connected to an extraction electrode power source 79 that is connected to a high voltage power source 82 . The filaments 651 and 652 of the liquid metal ion source 65
When a negative voltage of several tens of kilovolts is applied to the extraction electrode 67 after heating and melting it in a vacuum of 105 torr or less, ions are emitted from an extremely narrow area at the tip of the needle 653 of the liquid metal ion source 65. The beam is pulled out. In addition, the ion beam is indicated by the symbol 68 in FIG.
The spot is indicated by 68'.

The aberthier 69 is installed below the extraction electrode 67, and extracts only the vicinity of the center of the ion beam extracted by the extraction electrode 67.

The set of 9N lenses 70, 71, 72 is an Abatia 6 lens.
It is connected to a lens power source 80.81 arranged below the power source 9 and connected to a high voltage power source 82. These electrostatic lenses 70, 71, and 72 are designed to focus the ion beam extracted by the abatia 69.

The blanking electrode 73 is installed below the electrostatic lens 72 and is connected to the control device! The blanking electrode power supply 83 is connected to the blanking electrode power supply 85 .

This blanking electrode 73 scans the ion beam at an extremely high speed in a direction perpendicular to the direction toward the sample.
Avachia 7 installed below the blanking electrode 73
4, and the irradiation of the ion beam onto the sample is stopped at high speed.

The aberration 74 projects and images the spot of the ion beam onto the sample surface.

The set of deflection electrodes 75 and 76 is connected to a deflection electrode power source 84 which is installed below the avertia 74 and is connected to a control device 85. The deflection electrodes 75 and 76 direct the spot of the ion beam focused by the electrostatic Lt lenses 70 and 71° 72 into an X direction.

It is deflected in the Y direction and connected to a black spot defect on the sample.

a filament power supply 77 of the liquid metal ion source 65;
Power supply for control electrode 78. The high voltage power source 82 for applying voltage to the ion beam extraction electrode mold 179 and the lens power source 80.degree. 81 has a voltage of several 1.degree. KV.

The control device 85 controls a blanking electrode 'W1 source 83.
The blanking electrode 73 and the deflection electrodes 75 and 76 are controlled to operate according to a certain pattern through the deflection electrode power source 84.

The secondary charged particle detector 86 is installed facing the sample in the sample chamber 40, receives secondary electrons or secondary ions emitted from the sample when the sample is irradiated with an ion beam spot, and detects the intensity of the secondary electrons or secondary ions. is converted into a current strength and the signal is sent to the SIMI1m device 87.

The SIM III detection device 87 is equipped with a round tube 88. And SIMIl! The detection device 87 receives a signal regarding the amount of deflection of the ion beam in the X and Y directions from the deflection electrode power source 84, scans a bright spot on the cathode ray tube 88 in synchronization with the signal, and converts the brightness of the bright spot into the secondary charge. By changing the current intensity according to the signal sent from the particle detector 86, an image of the sample can be obtained according to the secondary electron emission ability at each point on the sample. Enables magnified observation of the sample surface.

The means 89 for preventing spot disturbance due to the charge of the ion beam is configured to direct the deflection 1 W! between the pole 76 and the sample. It is placed. The means 89 for preventing this spot disturbance shown in FIG. 8 has electronic jaws 890, 89i facing each other in a direction crossing the ion beam passage direction, and each electronic jaw 890, 891 has a cup-shaped main body. 892, a filament 893 provided inside the main body 892, and a grid-like extraction electrode 894 provided in the opening of the main body 892. Each electron jaw 890, 891 extracts an electron current 895 from the filament 893 using an extraction electrode 894 at an accelerating voltage of about 100V, emits the electron current 895 into the space through which the ion beam passes, and gives a negative charge to the ion beam. It is designed to neutralize it. In FIG. 8, reference numeral 68 is an ion beam, 75 and 76 are deflection electrodes,
90 indicates a sample.

Next, with reference to FIGS. 6 to 9 (1) to (4), an explanation will be given of the operation of the defect repairing apparatus of the embodiment described above and one implementation layer of the defect repair method of the present invention.

The mask with the black spot defect, that is, the sample 90, is placed on the sample stage 60 in the sample exchange chamber 41, and then the sample exchange chamber 41 is sealed, and after preliminary evacuation is performed by the vacuum evacuation system, the sample drawer is removed. 64 into the sample chamber 40,
Place it on the stage 55.

Next, the inside of the lens barrel 39 and sample chamber 40 is evacuated to 1
Evacuate to approximately 0.06 torr and maintain the vacuum state.

Next, the high-voltage power supply 82 and the control device 85 are activated, and the filament power supply 77 of the liquid metal ion source 65, the control electrode power supply 78, and the extraction electrode source 7 of the ion beam are activated.
9. Liquid metal ions i[
65 filaments 651, 652 electrodes 651', 6
52', control electrode 66, ion beam extraction electrode 67, electrostatic lenses 70, 71, 72, deflection electrode 75
A voltage is applied to each of the points.

Initially, the control electrode 66 and the extraction electrode 67
As a result, an ion beam 68 with a low acceleration voltage of several KV or less is extracted from the metal 654 serving as the ion source through the needle 653 of the liquid metal ion source 65, and the spot 68'
While scanning the sample 90, the stage 55 is moved in the x, y, z directions, and the θ direction via the moving micrometers 56, 57° 58, and the θ direction moving ring 59. SIMIR device by the signal from the secondary charged particle detector and the signal from the secondary charged particle detector! The surface of the sample is enlarged and displayed on a cathode ray tube 88 of 87, and black spot defects in the sample are observed.

Then, the moving micrometers 56, 57° 58 and the θ direction moving ring 59 are operated to remove the black spot defect 92 attached to the pattern 91 shown in FIG. 9(1).
As shown in Figure (2), the projection imaging range 9 of the Avatia 74
Match 3.

Next, a further 10 KV is applied to the extraction electrode 67 of the ion beam.
Applying a negative voltage of Beam 68
Extract only the central part using Chia 69 and attach it to the electrostatic lens 7.
A spot 68' of the ion beam 68 is irradiated onto the black spot defect 92 in the sample 90 while being focused at 0,71.72 and deflected in the X and Y directions by the deflection electrodes 75 and 76.

Then, when correcting the sunspot defect 92, as shown in FIG.
As shown in FIG.
Starting point x1 in the X direction at the irradiation position y1 in the first column of the direction
Then, the spot 68' is scanned in the X direction at the irradiation position y1 of the first row, and when it reaches the end point X- in the X direction, the blanking electrode 73 is activated. The spot 68' is removed from the Aberchia 74 so that the sample 90 is not irradiated, and the spot 68' is returned from the end point xm to the starting point x1, moved by Δy in the Move to the irradiation position y2 of the row, and from this position spot 68'
is scanned in the X direction again, and the above-described operation is repeated until the irradiation of the spot 68' at the last row of irradiation positions yn in the X direction is completed, thereby removing the black spot defect 92 as shown in FIG. 9(4). Can be removed.

By the way, the black spot defects of the mask targeted in the present invention and the patterns connected to the black spot defects are metals or metal compounds, and are separated from each other and are not grounded. Charges are accumulated in the pattern upon incidence, which affects the path of the ion beam that is incident later. In other words, the spot 68' of the ion beam 68 becomes large, the trajectory of the ion beam 68 deviates during scanning, or the edges of the projected image of the aberthia 74 are disturbed, which prevents satisfactory machining.

Therefore, an electron stream 895 is emitted toward the ion beam 68 from the electron jaws 890 and 891 of the means 89 for preventing disturbance of the spot due to the charge of the ion beam, and the ion beam 68 is neutralized by being given a negative charge. As a result, the spread of the ion beam 68 due to the space charge effect, the deviation of the trajectory when scanning the spot 68', or the spread of the ion beam 68 due to the space charge effect, or the
Since disturbances at the edges of the image can be prevented, the accuracy of correcting black spot defects can be further improved.

When taking out the mask that has been processed and corrected through the above steps,
A gate valve 42 provided between the lens barrel 39 and the sample chamber 40
, close the gate valve 43 provided between the sample chamber 40 and the sample exchange chamber 41 , pull out the sample stage 60 into the sample exchange chamber 41 using the sample drawer 64 , close the gate valve 43 , and close the door of the sample exchange chamber 41 . The mask is opened and the modified mask is taken out and sent to the subsequent process.

To show the conditions under which sunspot defects were actually removed, a Ga liquid metal ion source was extracted from a Ga liquid metal ion source at an accelerating voltage of 45 KV, and an electrostatic lens was used to remove a sunspot defect from a 600-thick Cr mask.
．． Good processing results were obtained by focusing the ion beam to 2 μφ and scanning the ion beam spot at a speed of 20 μ/sec using a deflection power source.

Next, various different embodiments of the present invention will be described.

First, the vacuum evacuation system is not limited to the one shown in FIG. 6, but may be constructed by combining an oil rotary pump, a diffusion pump, and an oil trap, or a combination of an oil rotary pump, a cryopump, and an ion pump. It may also be configured in combination with a titanium pump.

Further, the ion source is not limited to the liquid metal ion source 65 shown in FIGS. 6 and 7, but it is also possible to use an extremely low-temperature field ionization type ion source that operates in a high vacuum of 10' torr or less.

FIG. 10 shows the cryogenic field ionization type ion source,
What is shown in FIG. 10 is a support portion 655 having a gas delivery hole 656, a metal needle 657 provided on the support portion 655. It includes an extraction electrode 658 that is electrically insulated from the support portion 655 by an insulator 659 such as sapphire. The support part 655 is connected to a liquid helium refrigerator, and the support part 655 and the needle 65
7 is cooled to liquid helium temperature by the refrigerator. An ionizing gas 660 such as a rare gas or H2 gas is fed through a hole 656 provided in the support portion 655, and the gas atoms are adsorbed on the surface of the needle 657, resulting in a high density. And the extraction electrode 658
As a voltage is applied to the needle 657 , the high voltage causes gas atoms to undergo electric field ionization from an extremely narrow region at the tip of the needle 657 and are extracted as an ion beam 661 . This ultra-low temperature field ion source has an extremely high adsorption density of gas atoms near the needle tip compared to a field ion source at a normal temperature, so it becomes a high brightness ion source.

Furthermore, the charged particle optical system that focuses the ion beam is not limited to the set of three electrostatic lenses 70°71.72 shown in FIG. 6, but it is also possible to use an Einzel lens.
Further, the number of lenses is not limited to three.

Furthermore, the order in which the lenses, blanking electrodes, aberrations, and deflection electrodes of the charged particle optical system are arranged is not limited to the order shown in FIG. 6, but can be changed in various ways.

FIGS. 11(1), (2), (3), and (4) show various embodiments of lenses and Abatia of charged particle optical systems.

The one shown in FIG. 11(1) has an Abatia 681 installed below an ion source 680, and a lens 70 below it.
A set of 0,701,702 is installed, and Avachia 6
The image output from 81 is projected onto the sample 90 by lenses 700, 701, and 702.

In addition, the one shown in FIG. 11(2) includes a pair of first-stage lenses 703, 704, and 705 below the ion source 680, and
A set of lenses 706, 707 in the first stage is arranged with an interval between them, and a pair of lenses 703, 704, 705 in the first stage and a string between the lenses 706, 707 in the second stage are
82 have been installed. The ion beam emitted from the ion source 680 is then transferred to the first stage lenses 703, 704, 705.
The parallel beam is converted into a parallel beam by the Avertia 682, and the central part of the parallel beam is taken out by the Aberthia 682, and its image is projected onto the sample 90 by the second-stage lenses 706 and 707. What is shown in FIG. 11 (2) is the
A larger portion of the ion beam can be used to irradiate the sample than that shown in Figure (1).

Next, what is shown in FIG. 11 (31, (4)) is the ion source 6.
The first stage lens 708, which is a zoom lens, is located below 80.
, 709, and 710, and below that, an Abatia 683 with a variable aperture size is installed, and further below that, a second-stage lens set of 711°, 712, and 713 is placed. In FIG. 11(3), the dimension b of the aperture of the Avatia 683 is adjusted narrowly, and the ion beam is directed through the opening of the Avatia 683 using the first-stage lenses 708, 709, and 710, which are zoom lenses. The image is narrowed down to a dimension C, which is slightly thicker than the dimension A, and the image emitted from the Avatia 683 is projected onto the sample 90 with a dimension a by the second-stage lenses 711, 712, and 713. Next, Figure 11 (
In 4), the aperture of the Avatia 683 is adjusted to a dimension b' that is wider than the dimension shown in FIG. 11 (3), and the ion beam is
The lenses 708, 709, and 710 in the second stage are stopped to a dimension C' that is slightly thicker than the dimension b', and the lens 71 in the second stage is
1.712, 713 to project onto the sample 90 in dimension a'. These Figure 11 (3), (4)
According to the configuration shown in , it is possible to irradiate a larger portion of the ion beam onto the sample 90 .

Although the opening of the abatia may be formed in any shape such as a circular shape or a polygon, it is easiest to use a rectangular shape with variable dimensions.

Figure 12 (1), (2), Figure 13 (1), (2), (
3), Fig. 14 (1), (2), (3), and Fig. 15 show Abatia with variable opening dimensions, how to use it, and sunspot defects and Abatia openings. The device used for positioning and dimension adjustment is shown.

The Avatia shown in FIGS. 12(1) and 12(2) consists of a first... second slide plates 685, 686, and a third slide plate opposed to each other in the Y direction. A fourth slide plate 687, 688 is attached to the wall 684 of the vacuum vessel so as to be operable from the outside, and Second.
Third. Fourth slide plate 685, 686, 687
, 688, respectively.
．． 2nd゜3rd. Fourth fine movement feeding means 689, 690, 6
91.692. Said 1st. The opposing surfaces of the second slide plates 685 and 686 and the opposing surfaces of the third and fourth slide plates 687 and 688 are formed into blade shapes. Also, 1st. Second slide plate 68
5,686 and the third. Fourth slide plate 687,6
88 and are arranged back-to-back via a contact surface 693. In this Abatia, the first. By operating the second fine movement feeding means 689, 690, the first and second slide plates 685, 686 move in the X direction, so the size and position of the opening in the X direction can be finely adjusted. 3. Fourth fine movement feeding means 691, 69
2, the 3rd and 4th slide plates 687 and 688 move in the Y direction.
Directional dimensions and position can be finely adjusted.

Figures 13 (1), (2), and (3) show that Figure 12 (1) and (2) above are applied when removing black spot defects that have adhered to areas where the spacing between adjacent patterns is narrow. As an example of use, as shown in FIG. 13(1), the abacus shown in FIGS. Cheer number 1. Second. 3rd ° 4th slide plate 685
, 686, 687° 688, and the adjusted aperture aperture surrounds the sunspot defect 96 in a rectangular frame 694, which is the projection imaging range, as shown in FIG. 13(2).

The spot is scanned within this frame 694 in the manner shown in FIG. 9 (3), and the black spot defect 96 is removed, as shown in FIG. 13 (3).
Modify the pattern 94 as shown in FIG.

Next, in FIG. 14 (1), (2), and (3), pattern 9
Large black spot defect 99 in pattern 97 out of 7.98
Figure 12 (1).

This shows an example of using the variable size aperture shown in (2) above, except that the rectangular frame 695 can be formed according to the position and size of the large sunspot defect 99. This is the same as that shown in FIGS. 13 (1), (2), and (3).

Furthermore, FIG. 15 shows an apparatus that uses a TV monitor to align the position and size of the black spot defect in the pattern and the aperture of the variable aperture size.

The device shown in this figure includes an electronic line generation unit 696 and a TV monitor 697. In this device, the first . Second. Third. Fourth fine movement feeding means 689, 69
0,691,692 is linked with a potentiometer, etc.
The future signal 698 is transmitted to the electronic line generation unit 696.
from this electronic line generating unit 696 to the TV monitor 697. Second. Third. Fourth
A signal 699 indicating the position of the slide plates 685, 686, 687° 688 is sent, and based on this signal, the position in the X direction is indicated on the TV monitor 697 by the electronic line X L IX2, and the position in the Y direction is indicated by Y.

Displayed on Y2 electronic line. Therefore, by using this device, the aperture opening of the aberthia can be precisely and easily adjusted to match the position and size of the sunspot defect.

The adjustment of the projection imaging range of the Abatia is shown in Figure 12 (1).
) and (2), the method is not limited to the mechanical method shown in (2), but may be performed using a deflector power supply.

Further, in the present invention, the ion beam electrode power source 79,
A dividing resistor may be used instead of the lens power source 79,80.

Proceed to Figure 16, Figure 17 (1), (2), and Figure 18.
The figure shows an embodiment different from that shown in FIG. 8 as a means for preventing spot disturbance due to charges of the ion beam.

The means shown in FIG.
is placed facing the surface of the sample 90, the electron stream 898 is irradiated onto the surface of the sample 90, and the sample 9 is irradiated with the ion beam.
Except for being able to prevent zero charge accumulation, the eighth
It is similar to that shown in the figure.

Next, the means shown in FIGS. 17(1) and (2) are X, Y.

It includes an arm 898 that can move in the Z direction and a prober 899 attached to it, and the arm 898 is grounded. Then, when the prober 899 is used in contact with the pattern 100 having the black spot defect 101 and the sample 90 is irradiated with the ion beam 68, the charge is transferred to the pattern 100.
0, through the prober 899 and arm 898 to ground. As a result, accumulation of charge on the sample 90 can be prevented.

Furthermore, in the method shown in FIG. 18, a mask substrate 901 is placed on a sample stage 60, and a thin film 903 of a metal or a conductive compound such as In2O, SnO2, etc. is vapor-deposited on the entire surface of the mask substrate 901, and conductive. Clamper 904 made of wood
Fix it with. Due to this.

The charge from the pattern 9o2 can be flowed to the ground through the clamper 904 made of a conductive material and the sample stage 60 without changing the transmittance of the mask, which is the sample, to light, X-rays, and ion beams.

Therefore, it is possible to prevent charge from accumulating during ion beam irradiation.

According to the embodiment described above, a sample chamber is formed in a vacuum container, a stage on which a mask is placed is provided in the sample chamber, and a liquid metal ion source or electrode is provided in the vacuum container facing the sample chamber. A high-intensity ion source such as a field ionization type ion source that operates at low temperatures is provided, and at least means for extracting an ion beam from the ion source and a charged particle optical system for focusing the extracted ion beam onto a spot; The system is equipped with a means to control the output and stability of the ion beam, spot diameter, and spot irradiation direction, and to irradiate the spot onto the sunspot defects on the mask, making it possible to reliably remove and repair the sunspot defects on the mask. .

〔Effect of the invention〕

As explained above, according to the present invention, an ion beam is extracted from a high-intensity ion source, the ion beam is focused into a minute spot by a charged particle optical system, and is irradiated onto a black spot defect of a mask as a sample. Since the black spot defects are removed, pattern ICs with a thickness of 1 to 1.5 microns to less than 1 micron are manufactured. It has the effect of being able to highly accurately correct black spot defects that occur in photomasks, X-ray exposure masks, ion beam exposure masks, etc., and has the effect of being able to be corrected with sufficient practical productivity.

Further, according to the present invention, since the black spot defects on the mask are irradiated while preventing the spot from being disturbed by the charges of the ion beam, it is possible to correct the defects with even higher precision.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of a photomask in which chromium metal etc. is vapor-deposited on a glass substrate, Fig. 2 is a plan view of the photomask showing black dot defects and white dot defects that occur on the mask, and Fig. 3 Figures 4 (1), (2), (3), (4), and (4) are diagrams showing a conventional mask defect correction device using laser processing.
5) is a diagram showing the manufacturing process of an X-ray mask and an example of its product, FIG. 5 is a vertical cross-sectional view showing an example of a mask for ion beam exposure, and FIG. 6 is a diagram showing the mask defect correction method of the present invention. A block diagram showing one embodiment of the device for carrying out the implementation, FIG.
FIG. 8 is an enlarged perspective view showing an embodiment of the liquid metal ion source in the apparatus shown in FIG. ), (2), (3), and (4) are diagrams showing an embodiment of the present invention carried out using the apparatus shown in Figure 6, and Figure 10 shows a different embodiment of the ion source. Enlarged cross-sectional view of a low-temperature field ion source, Figure 11 (1), (2),
(3) and (4) are diagrams showing various embodiments of different combinations of the lens of the charged particle optical system and the Abatia that projects and images the ion beam onto the sample, and Figure 12 (1). oh
13(1) and (2) are enlarged longitudinal sectional front and side views of 7 perches with variable opening dimensions. (3) and Figures 14 (1), (2), and (3) are diagrams showing the defect correction process performed using an aperture with variable opening dimensions, and Figure 15 is the position and size of the black spot defect. Figure 16 is a block diagram of a device for displaying the position and size alignment status of the aperture and the aperture of the aperture whose dimensions can be changed. FIG. 17 is a sectional view showing a different embodiment.
1) and (2) are front and plan views showing other embodiments of the means, and FIG. 18 is a longitudinal sectional view of another embodiment of the means. 37... Mount, 39... Lens barrel, 40... Sample chamber,
41... Sample exchange room, 42-54... Components of the vacuum evacuation system, 55... Stage, 56, 57, 58...
x, y. Micrometer moving in Z direction, 59... Ring moving in θ direction, 60... Sample stage, liquid metal ion source. 650-654... Constituent members of liquid metal ion source, 6
55-659... Components of a field ionization type ion source that operates at extremely low temperatures, 66... Control electrode. 67... Ion beam extraction electrode, 69,74°6
81.682,683...Abatia, 685-69
2...Avartia component with variable opening dimensions, 6
8... Ion beam, 68'... Ion beam spot, 70-72... Electrostatic lens of charged particle optical system, 700-713... Lens, 73... Blanking electrode, 75. 76... Deflection electrode, 77-84...
Power source for each electrode, 85...control device, 87...secondary charged particle detector, 89...means for preventing disturbance of spot due to charge of ion beam, 890-904...configuring the same means. member, 90...sample, 91,94°95
．． 97,98,100... pattern, 92.96.9
9,101...Sunspot defect.

Claims (1)

[Claims] 1. An ion beam is extracted from a high-intensity ion source such as a liquid metal ion source or a field ion source that operates at extremely low temperatures, and the ion beam is formed into a minute spot by a charged particle optical system. 1. A method for repairing defects in a mask, comprising: irradiating a mask with focused irradiation onto a black spot defect to remove the black spot defect. 2. An ion beam is extracted from a high-brightness ion source such as a liquid metal ion system or a field ionization type ion source that operates at extremely low temperatures, and the ion beam is focused into a minute spot by a charged particle optical system to form a black spot on the mask. 1. A method for repairing a defect in a mask, which comprises irradiating the defect and removing the black spot defect by preventing the spot from being disturbed by the charge of an ion beam.