JPH10241618A - Observation and machining method by charged beam and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the charge increase of charged beam and accurately detect a defect to machine and detect surely by observing a defective part of an insulating pattern formed on a board, after locally selecting and forming a conductive thin film around the defective part. SOLUTION: A circuit pattern forming shading film 2 and a deep-drilling type phase shifter 3 are formed at a circuit pattern forming part of a transparent board 1 to aim at exposure of high resolution. In case this phase shifter 3 has a defective part 4, the defective part 4 is previously detected by a defect inspecting device. On the basis of the coordinates of a defect position, focused ion beams 6 are irradiated to the peripheral part, which spraying CVD gas from a gas nozzle 5, and a conductive thin film 8 of 50mm or less such as W is formed and grounded. The focused ion beams 6 are then irradiated, and after detecting a defect 4 by a secondary particle detector 7, the defect 4 is eliminated. After correcting the defect 4, the thin film 8 is dissolved with 9 washing liquid, such an ammonia solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an observation and processing method using a charged beam.

[0002]

2. Description of the Related Art As semiconductors become more highly integrated, phase shift masks are being put to practical use in order to expose finer patterns at lower cost. FIG. 5 shows an example of this phase shift mask. In FIG. 1, a light-shielding film 2 for forming a circuit pattern and a deep-diffusion type phase shifter 3 are alternately provided on a region where a circuit pattern is to be formed on a transparent substrate 1. As shown in FIG. 5A, the light transmitted through the phase shifter 3 has a phase shift of π from the light transmitted through an adjacent pattern, so that high-resolution exposure is possible due to interference of light at the pattern boundary. It has become.

However, as shown in FIG. 5B, when a defect 4 exists on the phase shifter 3, the phase amplitude of the light transmitted through the defective portion is greatly shifted, and the defect is transferred to the element as it is. I will. Therefore, detecting and correcting this defect has become an important issue in the practical use of a phase shift mask. Defect 4 on phase shifter 3 shown in FIG.
Uses a defect inspection device to detect the position of a defect, irradiates a charged beam focused by an electrostatic lens on a peripheral part that seems to be defective while scanning it, and emits it from the substrate based on the coordinate data of the defect position. The secondary electron or secondary ion is detected by a secondary particle detector, the mask surface is observed, and the defective portion is corrected by a method using an ion beam described in JP-A-4-449. I do. At this time, it is also important to prevent the mask substrate from being damaged by the charged beam.

[0004]

The defect 4 on the phase shifter 3 shown in FIG. 5 (b) is irradiated with a focused charged beam while scanning it, and secondary electrons or secondary electrons emitted from the substrate are emitted. Detect ions and observe the mask surface.
As described in 449, the defect is corrected by a method of irradiating a focused ion beam to only the defect and scanning the same to remove the defect. However, since the mask itself is insulative, the charge of the irradiated charged beam does not escape to the ground, but is accumulated (charged up) on the mask surface, and the charged particle beam rebounds, so that the secondary particle image gradually becomes larger. Slipped,
Observation of a defect such as white streaks in the secondary particle image due to discharge becomes difficult. For example, when an ion beam is used as a charged beam, there is a method of neutralizing ions accumulated on the substrate surface using an electron shower as one of means for preventing charge-up. However, it is necessary to irradiate the processed part with the electron shower, and since the electron shower is used, an image in which the secondary electrons are detected cannot be obtained as a secondary particle image. Observation is possible only with the detected image. In this case, there remains a problem that an image with high contrast cannot be obtained because the yield of secondary ions is as low as several percent of the primary ions. For this reason, the detection of the defective portion and the accuracy of the correction processing position are reduced.

It is an object of the present invention to provide a substrate processing method capable of detecting and correcting a defect on a substrate including an insulator with high accuracy and ease, and an apparatus for implementing the method.

[0006]

The difficulty in observing a secondary particle image when observing a defect on a substrate containing an insulator is that the charge of the irradiated charged beam is grounded because the substrate itself is insulative. This is because the charge beam is accumulated (charged up) on the substrate surface without escaping, and the irradiated charged beam is repelled. Therefore, if the substrate itself is made conductive and grounded, charge-up can be prevented. This is achieved by providing a conductive thin film on the substrate surface and grounding.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> As a first embodiment of the present invention, a conductive thin film is formed on a defect of a phase shift mask,
A method of detecting and correcting a defect of the phase shifter will be described with reference to FIG. In the figure, 1 is a transparent substrate, 2 is a conductive light shielding film, 3
Is a phase shifter, and 4 is a defect. As described above, when the phase shifter 3 has the defect 4, the phase amplitude of the light transmitted through the defective portion is largely shifted. Therefore, the focused ion beam 6 is used for this defect correction. First, a defect inspection apparatus detects the position of a defect in advance, and irradiates a focused ion beam with a focused ion beam while blowing a CVD gas from a gas nozzle 5 to a peripheral portion considered to be defective based on coordinate data of the defect position. A thin film 8 is formed. A W film is formed using, for example, W (CO) ₆ as a CVD gas. At this time, the thickness of the conductive thin film is such that the shape of the defect is not buried, and is preferably 50 nm or less. In addition, it is necessary to deposit the conductive thin film from a portion considered to be defective to the conductive light-shielding film grounded by the substrate holder, or to directly ground the conductive film including the conductive thin film by a prober or the like. Thereafter, the focused ion beam 6 is scanned, secondary particles emitted from the surface of the formed conductive thin film are detected by the secondary particle detector 7, and the scanned ion image is observed. Based on the scanned ion image, the position of the defect 4 of the phase shifter is detected, the irradiation area of the focused ion beam 6 is set, and the focused ion beam 6 is irradiated only on the defect portion to remove and correct the defect 4. After the correction, the thin film 8 is washed and removed with a solution 9 that sufficiently melts the thin film such as ammonia.

<Second Embodiment> As a second embodiment of the present invention, a method of detecting and correcting defects using a conductive thin film such as tungsten on a defect of a phase shift mask by irradiating with argon ions will be described. 2 will be described. A defect 4 on the phase shifter 3 is detected by a defect inspection device, and based on coordinate data of the defect position, a gas nozzle 5 is used as a CVD gas at a peripheral portion considered to have a defect, for example, W gas.
Argon ion gun 1 while blowing (CO) ₆ gas
Irradiate with argon ions by tungsten thin film 8
To form At this time, as in the first embodiment, the thickness of the tungsten thin film 8 is such that the shape of the defect 4 is not buried, and is preferably 50 nm or less. Further, it is necessary to deposit the tungsten thin film 8 from a portion considered to be defective to the conductive light-shielding film grounded by the substrate holder, or to ground the conductive film including the conductive thin film directly with a prober or the like.
Thereafter, similarly to the first embodiment, for example, the focused ion beam 6
The defect 4 is observed and corrected using the method described above. After the correction, the tungsten thin film 8 is removed with an ammonia solution 9.

The configuration method is equivalent to the configuration method shown in FIG.

<Third Embodiment> As a third embodiment of the present invention, a method for detecting and correcting defects after forming a conductive thin film such as molybdenum on the defects of a phase shift mask by laser CVD. This will be described with reference to FIG. First,
The phase shift mask is introduced into the laser CVD apparatus, and the chamber of the laser CVD apparatus is filled with the CVD gas 12. As the CVD gas 12, for example, Mo (CO) ₆ is used. Thereafter, as described above, the defect 4 on the phase shifter 3 is detected by the defect inspection device, and the laser 11 is applied to a peripheral portion considered to be defective based on the coordinate data of the defect position.
To form the Mo thin film 8. At this time, as in the first embodiment, the thickness of the Mo thin film 8 is such that the shape of the defect is not buried, and is preferably 50 nm or less. Also, M
The o thin film 8 needs to be deposited from a portion considered to be the defect 4 to a conductive light shielding film that is grounded. Thereafter, similarly to the above embodiment, the defect 4 is observed using, for example, a focused ion beam 6, and after the correction, the Mo thin film 8 is removed with an ammonia solution.

<Fourth Embodiment> As a fourth embodiment of the present invention, a method of detecting and correcting a defect using a conductive thin film such as a palladium complex on a defect of a phase shift mask will be described with reference to FIG. Will be explained. A defect 4 on the phase shifter 3 is detected by a defect inspection apparatus, and a small amount of a palladium complex 14 is applied from a micropipette 13 to a peripheral portion considered to be defective based on the coordinate data of the defect position.
Irradiation 1 is performed to form a Pd thin film 8 by thermal decomposition. At this time, as in the first embodiment, the thickness of the Pd thin film 8 is
Is not buried, and is preferably 50 nm or less. In addition, it is necessary to deposit the Pd thin film 8 from the portion considered to be the defect 4 to the grounded conductive light shielding film. Then, similarly to the above embodiment, the defect 4 is observed using, for example, a focused ion beam 6, and after correction, the Pd thin film 8 is removed with hot sulfuric acid.

<Fifth Embodiment> As a fifth embodiment of the present invention, a method for detecting and correcting a defect on a liquid crystal TFT substrate will be described. When a break occurs in a part of a data line or a gate line of a liquid crystal TFT having a small size per pixel such as a projector, a TFT substrate has a line defect. Therefore, a charged beam is used as a method for detecting this defect. First, the position of a defect is detected in advance by a defect inspection device, and based on the coordinate data of the defect position, a portion considered to be defective is observed and corrected using the first to fourth embodiments, and then the conductive thin film is removed.

<Sixth Embodiment> As a sixth embodiment of the present invention, an observation and processing method when the surface of an LSI substrate is covered with an insulating layer will be described. When the surface of the LSI substrate is covered with an insulating layer, charge-up occurs as in the case of the phase shift mask, making it difficult to observe a secondary particle image. Therefore, after forming a conductive thin film on a portion which seems to have a defect using Examples 1 to 4, observation and various processing (for example, correction of a defective portion) are performed as necessary, and the conductive thin film is formed. Remove. In the case of an LSI substrate, as a method of detecting a lower layer defect in a multilayer structure, for example, after processing a cross section with a focused ion beam, a conductive thin film is formed on a cross section observation surface and grounded, and then cross section observation can be performed. It is.

<Seventh Embodiment> As a seventh embodiment of the present invention, a method for detecting and correcting defects by using a conductive thin film such as carbon on defects of a phase shift mask by irradiating with argon ions will be described. 6 will be described. As described above, the defect on the phase shifter is detected by the defect inspection device,
A sublimation gas containing a large amount of carbon such as pyrene (C ₁₆ H ₁₀ ) or naphthalene (C ₁₀ H ₈ ) as a CVD gas from a gas nozzle 5 to a peripheral portion considered to have a defect based on the coordinate data of the defect position. While spraying 15,
Irradiation of argon ions with an argon ion gun 10 forms a carbon thin film. At this time, as in the first embodiment,
The thickness of the carbon thin film 8 is such that the shape of the defect 4 is not buried, and is desirably 50 nm or less. Further, it is necessary to deposit the carbon thin film 8 from a portion considered to be defective to the conductive light shielding film grounded by the substrate holder, or to ground the conductive film including the conductive thin film directly with a prober or the like. Thereafter, defects are observed and corrected using, for example, a focused ion beam as in the first embodiment. After the correction, the carbon thin film 8 is removed by changing the argon gas 16 of the argon ion gun 10 to oxygen gas 17 and irradiating with oxygen, heating the substrate in an oxygen atmosphere or irradiating ultraviolet rays, or removing by ashing with plasma.

In this case, the ion gun chamber 28 is provided in the preliminary chamber 20 to form and remove the carbon thin film as shown in FIG. 7 or the ion gun chamber 28 is provided in the process chamber 18 as shown in FIG. A configuration method for forming and removing a carbon thin film in the chamber is also conceivable.

<Eighth Embodiment> As an eighth embodiment of the present invention, FIG. 9 shows a method of grounding a conductive thin film formed in the embodiment more accurately with a prober.

First, as in the embodiment, a conductive thin film 8 is formed on a portion considered to be defective. At this time, the thickness a of the conductive thin film in a portion that does not hinder the observation of defects is set to 0.1 to 0.1.
It is formed as thick as about 5 μm. Thereafter, the prober 29, which is grounded at the thicker portion, is lowered by the height of b so as not to penetrate the conductive thin film and is grounded. Here, the thickness of the conductive thin film is observed using an STM prober as a prober, and the STM prober 29 is lowered by the height of b so as not to penetrate the conductive thin film at a thicker portion, and is grounded. More accurate grounding. After grounding, the surrounding area that seems to be defective is irradiated with a charged beam focused by an electrostatic lens while scanning, and secondary electrons or secondary ions emitted from the substrate are detected by a secondary particle detector And
Observe and process.

<Ninth Embodiment> As a ninth embodiment of the present invention, a method for grounding the conductive thin film formed in the embodiment will be described.
FIG. 10 shows a method of forming a conductive thin film locally by sputtering and grounding the conductive thin film. When there is a conductive film 8 near the outside of the substrate 1, the conductivity can be grounded by contacting the grounded substrate holder, but the isolated pattern at the center cannot be grounded. Therefore, the rotatable plate 30 having the slit is placed on the upper portion of the substrate 1, the slit portion is aligned with the position including the defect, and the target 31 for forming a conductive thin film is sputtered in an argon gas 16 atmosphere to form a conductive film. A thin film is formed from the center of the substrate to the outer conductive film that is grounded, and grounded. The plate having the slit does not necessarily need to be rotated, and may be movable in one axis direction or two axis directions. After grounding, the surrounding area that seems to be defective is irradiated with a charged beam focused by an electrostatic lens while scanning, and secondary electrons or secondary ions emitted from the substrate are detected by a secondary particle detector And observe and process.

<Tenth Embodiment> As a tenth embodiment of the present invention, a method for preventing the charge-up of the conductive thin film formed in the embodiment by canceling the charged beam is shown in FIGS. As in the embodiment, the conductive thin film 8 is formed at a portion considered to be defective. Also, a conductive film 32 is formed locally or on the entire back surface of the substrate. After that, when the defect is observed using, for example, the ion beam 6, a beam having a property opposite to that of a charged beam used for observation on a conductive film including a conductive thin film at the edge of the substrate as shown in FIG. The beam 33 is irradiated. FIG. 12 shows the electron beam obliquely incident on a conductive film including a conductive thin film that does not affect observation. At this time, while monitoring the capacitance or voltage on the conductive film on the back surface of the substrate and the surface of the substrate with the measuring device 34, the current value of the electron beam is changed so that the accumulation of charges on the substrate surface is eliminated. Here, the acceleration voltage of the electron beam is required to reduce the emission of secondary electrons, and is desirably 1 keV or less. Thereafter, secondary electrons or secondary ions emitted from the substrate are detected by a secondary particle detector, and observation and processing are performed as in the embodiment.

<Eleventh Embodiment> As an eleventh embodiment of the present invention, a method of grounding a conductive thin film formed in the embodiment with a conductive sheet or mesh will be described. As in the embodiment, a conductive thin film is formed on a portion considered to be defective. The conductive film including the conductive thin film is led out of the observation and processing area, and is led to a place other than the observation and processing area so as not to hinder the observation. Thereafter, a conductive sheet or mesh grounded so as not to hinder observation and processing is covered on a part or the whole surface, and thereby grounded. At this time, it is desirable that the sheet and the mesh do not damage the substrate surface. After grounding, the surrounding area that seems to be defective is irradiated with a charged beam focused by an electrostatic lens while scanning, and secondary electrons or secondary ions emitted from the substrate are detected by a secondary particle detector And observe,
Perform processing.

Here, as a method for preventing damage to the mask substrate, a coating film having a flat surface on the entire surface of the mask or on the periphery of the processed portion is provided on the mask before correction as described in JP-A-8-122012. There is also a method of forming a film having a film thickness 1.2 times or more as large as the step formed by the light-shielding film pattern or the phase shifter layer, but a flat film or a film having a large film thickness makes secondary particle detection difficult. I do.
For this reason, it is preferable to use a uniformly thin film of about 50 nm to prevent damage to the mask substrate as in the embodiment.

[0023]

According to the present invention, observation and processing of a substrate containing an insulator can be easily performed. In particular, defects on the phase shift mask can be easily detected and corrected. In addition, the mask itself is protected by a conductive film when detecting the secondary particle image, which reduces ion source implantation and prevents charge-up, enabling observation using either a secondary electron image or a secondary ion image. By selecting an appropriate conductive film, the yield of secondary particles can be improved. In addition, if the conductive thin film is selected from a material that can be sufficiently melted in a later washing step or a material that can be easily removed, contamination by the conductive film is eliminated.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a correction method according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a correction method according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram of a correction method according to a third embodiment of the present invention.

FIG. 4 is an explanatory diagram of a correction method according to a fourth embodiment of the present invention.

FIG. 5 is a diagram illustrating an example of a phase shift mask.

FIG. 6 is an explanatory diagram of a correction method according to the second and seventh embodiments of the present invention.

FIG. 7 is an explanatory diagram of a correction method according to a seventh embodiment of the present invention.

FIG. 8 is an explanatory diagram of a correction method according to a seventh embodiment of the present invention.

FIG. 9 is an explanatory diagram of a correction method according to an eighth embodiment of the present invention.

FIG. 10 is an explanatory diagram of a correction method according to a ninth embodiment of the present invention.

FIG. 11 is an explanatory diagram of a correction method according to a tenth embodiment of the present invention.

FIG. 12 is an explanatory diagram of a correction method according to a tenth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transparent substrate, 2 ... Conductive light shielding film, 3 ... Phase shifter, 4
... defect part, 5 ... gas nozzle, 6 ... focused ion beam,
7: secondary particle detector, 8: conductive thin film, 9: cleaning liquid.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshinobu Mizumura 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside of Hitachi, Ltd. Hitachi, Ltd., Production Technology Laboratory (72) Inventor Mikio Hongo 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi, Ltd. Production Technology Laboratory (72) Katsuo Mizukoshi 292, Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Hitachi, Ltd. Production Technology Research Laboratories (72) Inventor Hirohiro Koizumi 5--20-1, Kamimizuhonmachi, Kodaira-shi, Tokyo Semiconductor Company, Hitachi, Ltd.

Claims (18)

[Claims] 1. A charged beam, wherein a conductive thin film for preventing accumulation of charges of the charged beam is locally selected and formed when observing and processing a substrate containing an insulator by the charged beam. Observation and processing methods. 2. When a substrate containing an insulator is observed and processed by a charged beam, a conductive thin film for preventing accumulation of charges of the charged beam is formed on a desired region by a gas nozzle.
An observation and processing method using a charged beam, wherein the charged beam is formed by spraying a VD gas. 3. When a substrate containing an insulator is observed and processed by a charged beam, a conductive thin film for preventing accumulation of charges of the charged beam is formed on a desired region by a gas nozzle.
An observation and processing method using a charged beam, wherein a VD gas is formed by spraying ion gas. 4. When observing and processing a substrate containing an insulator by using a charged beam, a conductive thin film for preventing accumulation of charges of the charged beam is formed by filling a desired region with a CVD gas and using a laser. Observation and processing method using charged beam characterized by the following. 5. When observing and processing a substrate containing an insulator by using a charged beam, a conductive thin film for preventing accumulation of charges of the charged beam is applied to a desired region with a micro-pipette of a small amount of a complex and a laser is used. An observation and processing method using a charged beam characterized by forming. 6. When observing and processing a substrate containing an insulator with a charged beam, a thin conductive thin film having a thickness of 50 nm or less is locally selected to prevent accumulation of charges of the charged beam.
Observation and processing method using charged beam characterized by forming. 7. When observing and processing a substrate containing an insulator by using a charged beam, a CVD gas is sprayed by a gas nozzle onto a desired region with a thin conductive thin film of 50 nm or less in order to prevent accumulation of charges of the charged beam. Observation by a charged beam, characterized by being formed by the charged beam,
Processing method. 8. When observing and processing a substrate containing an insulator by using a charged beam, a CVD gas is sprayed onto a desired region with a thin conductive film having a thickness of 50 nm or less from a gas nozzle in order to prevent accumulation of charges of the charged beam. An observation and processing method using a charged beam, characterized by being formed by an ion gas. 9. When observing and processing a substrate containing an insulator by using a charged beam, a thin conductive thin film of 50 nm or less is deposited on a desired region to prevent accumulation of charges of the charged beam.
An observation and processing method using a charged beam, wherein the method is formed by filling a VD gas and using a laser. 10. When observing and processing a substrate containing an insulator by using a charged beam, a thin conductive thin film having a thickness of 50 nm or less is deposited in a desired area with a micropipette to prevent accumulation of charges of the charged beam. An observation and processing method using a charged beam, wherein the method is applied and formed by a laser. 11. The method of claim 1, 2, 3, 4, 5, 6, 7,
In 8, 9, or 10, the observation and processing method using a charged beam in which the thin film emits more secondary electrons or secondary ions than an insulating material serving as a base. 12. The method of claim 1, 2, 3, 4, 5, 6, 7,
An observation and processing method using a charged beam which is connected to a place where the conductive thin film for preventing the accumulation of the charge of 8, 9 or 10 can be directly or indirectly grounded. 13. The method of claim 1, 2, 3, 4, 5, 6, 7,
The method for grounding a conductive thin film for preventing the accumulation of electric charge of 8, 9 or 10 according to the method of observing and processing a conductive film including the conductive thin film by using a charged beam which is brought into contact with a previously grounded probe and grounded. 14. The method of claim 1, 2, 3, 4, 5, 6, 7,
In the above-described method for grounding a conductive thin film for preventing the accumulation of charges of 8, 9, or 10, the grounded substrate holder is brought into contact with a conductive film on a substrate, and the grounded conductive film is insulated from an observation region. An observation and processing method using a charged beam through which an object is conducted through the conductive thin film. 15. The method of claim 1, 2, 3, 4, 5, 6, 7,
In the above-mentioned method of grounding a conductive thin film for preventing the accumulation of charges of 8, 9 or 10, the charge beam having a property opposite to that of a charged beam used for observation is accumulated in a conductive film containing the conductive thin film. Observation and processing method using charged beam to irradiate. 16. The method of claim 1, 2, 3, 4, 5, 6, 7,
In the above-described method for grounding a conductive thin film for preventing the accumulation of charges of 8, 9, or 10, when the grounded conductive film is under an insulator layer, the insulating layer is removed and the conductive film is removed. Observation and processing method using a charged beam that forms a thin film and grounds. 17. The method of claim 1, 2, 3, 4, 5, 6, 7,
In the above-mentioned method of grounding a conductive thin film for preventing the accumulation of charges of 8, 9 or 10, the conductive film including the conductive thin film is led out of the observation and processing region, and grounded in a place other than the observation and processing region. Observation and processing method using a charged beam that covers the grounded conductive sheet or mesh and grounds it. 18. An energy beam source for generating an energy beam such as an electron beam or an ion beam, a focusing optical system, a stage, a secondary particle detection system, a conductive thin film deposition system, and a controller for driving and controlling them. An apparatus for processing the substrate including a predetermined insulating pattern provided on the substrate, the method including irradiating a desired area of the substrate on the stage with an energy beam and simultaneously changing a state of the desired area. An observation and processing method using a charged beam, characterized in that observation can be performed by detecting secondary particles.