JP2000232047A - Correction method of scattered stencil type reticle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a correction method of a scattered stencil type reticle capable of obtaining a reticle which has high electron beam scattering performance and does not absorb an electron beam comparatively. SOLUTION: A plurality of gases constituting an electron beam scattering member are fixed in a vessel 1, and mixed gas is supplied from the vessel 1 to the vicinity of a substrate 7 in a vacuum chamber 4 via a piping 2. At this time, the flow rate of the mixed gas is adjusted with a mass flow controller(MFC) 3 installed in the piping 2. A converging ion beam is irradiated from a beam source 5 installed in a top part of the vacuum chamber 4 to the mixed gas supply region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a stencil type reticle used for lithography by electron beam reduction projection.

[0002]

2. Description of the Related Art A scattering stencil type reticle used for electron beam reduced projection lithography always has a pattern defect at the time of its manufacture. Therefore, it is urgently necessary to develop a technique for correcting the defect of the scattering stencil type reticle pattern, as well as the correction of the pattern defect of the photo reticle for reduction projection exposure using ultraviolet light which is currently in practical use.

The pattern defect includes a so-called white defect in which an electron beam scatterer pattern for scattering an electron beam is missing, and an unnecessary electron beam scatterer in a portion through which the electron beam must pass. There are so-called black defects. The present inventors, as a method of correcting the white defect of the scattering stencil type reticle pattern among these, selective film formation using a focused ion beam, electron beam, ultra-small plasma, etc.
It is believed that so-called FIB-CVD, EB-CVD, and selective plasma CVD can be put to practical use.

[0004]

The reticle material used in the electron beam reduction projection exposure method is required to have such characteristics that it hardly transmits an electron beam, sufficiently scatters an electron beam, and does not absorb the electron beam. You. Further, the reticle material needs to have a certain degree of conductivity in order to prevent charge-up during electron beam irradiation.

As materials satisfying these characteristics, from the viewpoint of electron beam scattering, a metal material having improved electron scattering ability, a large atomic weight, and also being conductive is excellent. However, since a metal material absorbs an electron beam well and generates heat as a result, a reticle made of a metal material has a large amount of thermal deformation, and for example, a resolution of 0.5 μm or less in a critical pattern. It is not suitable as a required reticle material.

On the other hand, when an inorganic material such as silicon or a carbon material is used as a reticle material, about 10
When an electron beam is irradiated at a high accelerating voltage of 0 keV or more, most of the electron beam is transmitted or scattered to a thickness of several μm, and the absorption amount is considered to be only about 2%.
Heat generation due to electron absorption is very small.

On the other hand, as described above, selective film formation methods such as the FIB-CVD method have been regarded as promising for correcting white defects. However, the density of the selective CVD film formed mainly of silicon or carbon is lower than the density of the reticle bulk (silicon single crystal). It is much worse than scattering materials.

Under these circumstances, there is an urgent need to obtain a reticle film having a high electron beam scattering ability and relatively not absorbing an electron beam. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for correcting a scattering stencil-type reticle that can obtain a reticle having a high electron beam scattering ability and relatively absorbing an electron beam.

[0009]

In order to solve the above-mentioned problems, a method for correcting a scattering stencil-type reticle according to the present invention has a pattern transfer section composed of an electron beam scatterer.
A method for correcting a defect generated at the time of manufacturing a reticle used when transferring a reduced projection transfer image to a transfer target substrate, wherein a plurality of gaseous substances constituting an electron beam scatterer are mixed at a desired mixing ratio. In a mixed state, the film is supplied to the defect portion, and a film is selectively formed on the defect portion by using any one of an excitation source of a focused ion beam, an electron beam, and an extremely small plasma.

A method for correcting a scattering stencil type reticle according to the present invention has a pattern transfer portion constituted by an electron beam scatterer, and is used for manufacturing a reticle used when transferring a reduced projection transfer image onto a transfer target substrate. It is a method of correcting the defect generated at the time, by supplying a plurality of substances constituting the electron beam scatterer to the defect portion alone in a gasified state, a desired concentration and the vicinity of the defect portion A material gas atmosphere having a mixed composition ratio is used, and a film is selectively formed on the defect portion by using any one of an excitation source of a focused ion beam, an electron beam, and an extremely small plasma.

A method of correcting a scattering stencil type reticle according to the present invention has a pattern transfer portion constituted by an electron beam scatterer, and is used for manufacturing a reticle used when transferring a reduced projection transfer image to a transfer target substrate. A method for correcting defects generated at the time of mixing, a plurality of substances constituting the electron beam scatterer are mixed at a predetermined mixing ratio, and the mixed substance is supplied to the defect portion, and a focused ion beam, an electron beam And a film is selectively formed on the defect portion by using any one of an excitation source of a micro-plasma and an ultra-small plasma.

According to these configurations, a plurality of substances constituting the electron beam scatterer are mixed at a predetermined mixing ratio, and the mixed plurality of substances are supplied to the defect, and the focused ion beam, the electron beam, And a film is selectively formed on the defective portion by using any one of an excitation source out of an ultra-small plasma. Thereby, the electron scattering ability is adjusted. Therefore, it is possible to obtain a reticle having a high electron beam scattering ability and relatively not absorbing an electron beam.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail. In the white defect correction, a gaseous material is supplied at an appropriate concentration in the vicinity of a necessary defect portion of the electron beam scatterer, and then the condensed ion beam or the electron beam is irradiated to the white defect correction portion. A film is selectively deposited on the defective portion. In this method, the FI
B-CVD method, EB-CVD method, or ultra-small plasma C
It can be implemented by the VD method or the like.

The material to be supplied to the defect portion of the electron beam scatterer is limited to some extent by the properties and composition of the film to be formed. For example, when a conductive film is to be formed, an organic metal compound containing a desired metal atom may be used as a material. Specifically, when a film containing tungsten as a main component is desired to be obtained, hexacarbonyl tungsten (W (CO) ₆ ) is appropriately heated and introduced into the vicinity of a sample in a vacuum chamber as a constant vapor pressure. Then, the portion to be formed is irradiated with an electron beam, a focused ion beam or the like while scanning. Thus, a film containing tungsten and carbon as main components can be selectively deposited only on the portion where the film is to be formed. The composition of the film contains hydrogen, oxygen, and the like in addition to tungsten and carbon. Also, FIB
When the film is formed by the CVD method, the film contains ions (for example, gallium) that form a convergent beam to some extent.

As described above, the electron scatterer of the scattering stencil type reticle for electron beam reduction projection lithography includes:
It is required to have a property of sufficiently scattering an electron beam and hardly absorbing the electron beam. The electron scattering ability is higher as the atomic weight of the constituent atoms is smaller, and is higher as the film density is higher. On the other hand, electron beam absorption increases as the atomic weight increases and as the film density increases.

As described above, the electron scattering ability and the electron beam absorption are in conflicting conditions. After all, as a film forming material satisfying such conditions, a material containing silicon or carbon as a main component is preferable. However, regardless of whether a focused ion beam, an electron beam, or an ultra-small plasma source is used as the excitation source, the film density of the resulting film is at most as large as that of the bulk (reticle material). It is considered to be around 80%, or at least 10% or less. The film formed in such a state has an extremely low electron scattering ability and is insufficient as an electron beam scatterer material.

The inventors of the present invention have conducted intensive studies based on the above fact, and as a result, have improved the electron scattering ability by dispersing metal atoms in a film containing silicon or carbon as a main component at a predetermined mixing ratio. It has been found that it is possible to cause the present invention.

It is to be noted that, for different types of metal atoms, the optimum mixing ratios are different. In addition, it differs depending on whether the main component of the film is silicon or carbon. The present invention
It discloses how to supply a plurality of material gas sources in the vicinity of a sample (film-forming object: reticle) when selectively forming a film using such a plurality of substances.

However, when supplying a plurality of materials to the vicinity of the sample, it is necessary to take into consideration the reactivity between the respective substances, and also, to supply the plurality of materials so that the film has the characteristics described above. The mixing ratio of the substances must also be controlled.

First, at least one of the plurality of material gases has a high reactivity and forms a chemical bond with another material substance, and is gasified as it is and supplied to the vicinity of the sample. If this is not possible, or if gaseous supply is possible, but the properties such as electron scattering ability and electron absorption of the film cannot be satisfied, a plurality of materials may be gasified independently and supplied near the sample. desirable.

For example, when a film is formed using tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ) as a silicon source and hexacarbonyl tungsten (W (CO ₂ ) ₆ ) as a metal material, tetraethoxysilane Reacts with moisture in the air to cause hydrolysis, and bonds to tetraethoxysilane itself or hexacarbonyltungsten, and in some cases, gels. If it is left as it is, it is gasified and cannot be guided near the sample. In such a case, a plurality of materials are individually gasified and supplied to the vicinity of the sample.

If a plurality of materials do not react with each other either alone or when mixing a plurality of substances, the plurality of materials may be mixed in advance, and the mixture may be directly gasified and supplied to the vicinity of the sample.

When each substance is supplied alone to the vicinity of the sample, the composition of the film can be controlled by controlling the supply amount of each gas. In this case, since the respective vapor pressures are generally different from each other, the mixing ratio when a plurality of substances are mixed is not directly reflected in the composition ratio of the gas supplied to the vicinity of the sample. That is, when gasifying the mixture,
It is desirable to mix them so that the gasified molecular composition ratio becomes a desired ratio and a desired concentration. However, the gas concentration greatly depends on the vapor pressure of each substance, the temperature for gasification, and the like. Therefore, it is preferable to appropriately set the gas concentration in consideration of these factors.

When a plurality of substances are supplied to the vicinity of a sample (a portion where selective film formation is desired) by using these methods, for example, when a focused ion beam, an electron beam, an extremely small plasma source, or the like is irradiated, the irradiation is performed. The excited part is excited, and selective film formation is performed by a plurality of substances.

When an electron beam and a focused ion beam are compared as an excitation source, the incident energy contributing to film formation is much higher in the focused ion beam, and the density of the film is higher.
It is generally known that the film formation rate is high, and it is more desirable for the focused ion beam to have a large atomic weight of the ion species. When a practical selective film formation is performed by obliquely incident an electron beam, it is necessary to have a high energy of about 30 kV or more and a beam current of 50 pA or more. Therefore, it is desirable to use a focused ion beam in consideration of productivity.

In consideration of the above, silicon or carbon is desirable as a main component of the film forming material. For example, when supplying around the white defect part for the purpose of selective film formation of a silane compound, an organosilane compound can be used as the material gas. Specifically, tetramethylsilane, trimethylethylsilane, dimethyldiethylsilane, and the like can be given.

Further, halosilane compounds in which the hydrolyzing group is a halogen atom, carboxysilane compounds in which the hydrolyzing group is a carboxy group, ketoxime silane compounds in which the hydrolyzing group is a ketoxime group, or alkoxy groups in which the hydrolyzing group is an alkoxy group Alkoxysilane compounds that are groups can be used. Preferably, alkoxysilane compounds are good.

Specific compounds include dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-
Chloropropylmethyldiethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxyquinsilane, γ-aminopropylmethyldimethoxysilane , Γ-aminopropylmethyldiethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, methyltrimethoxysilane, methyltriethoxy Silane, methyltripropoxysilane,
Methyltributoxysilane, methyltris (2-methoxyethoxy) silane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane,
Ethyltributoxysilane, ethyltris (2-methoxyethoxy) silane, propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, vinyltrimethoxysilane, vinyl Triethoxysilane, vinyltris (2-methoxyethoxy) silane, phenyltrimethoxysilane, phenyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxy Silane, 3,3,3-trifluoropropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-aminopropyl Ropirtrimethoxysilane, γ
-Aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, chloromethyltrimethoxysilane, chloromethyltriethoxyxanlan, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-
β-aminoethyl-γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethokine silane,
γ-glindoxypropyltriethoxysilane, (3,
4-epoxycyclohexylmethyl) trimethoxysilane, (3,4-epoxycyclohexylmethyl) triethoxysilane, β- (3,4-epoxycyclohexylethyl) trimethoxysilane, β- (3,4-epoxycyclohexylethyl) ) Triethoxysilane, tetramethoxysilane, tetraethoxysilane, tetopropoxysilane, tetrabutoxysilane, 1,1-bis (trimethoxysilyl) ethane, 1,1-bis (triethoxysilyl) ethane, 1,2-bis (Trimethoxysilyl)
Ethane, 1,2-bis (triethoxysilyl) ethane,
1,3-bis (trimethoxysilyl) propane, 1,3
-Bis (triethoxysilyl) propane, 2,2-bis (trimethoxysilyl) propane, 2,2-bis (triethoxyquinyl) propane, and the like.

Further, when carbon compounds are selectively simulated, naphthalene, biphenylene, acenaphthylene, fluorene, phenalene, phenanthrene, anthracene, fluoranthene, acephenanthrylene, aceanthrylene, having a benzene ring as a main lattice, Triphenylene,
Condensed polycyclic hydrocarbons such as pyrene, chrysene, naphthacene, pleiadene, picene, perylene, pentaphen, and pentacene, and ortho-condensed and peri-condensed polycyclic hydrocarbons are effective as material gases. In addition, styrene, HMDS (hexamethyldisilazane), HMCTS
(Hexamethylchlorotrisilane), MIBK (methyl iributyl ketone), IPA (isopropyl alcohol) and the like can also be used as a carbon compound for film formation.

As the additive substance, a metal compound is desirable.
Hexacarbonyl tungsten (W (CO)₆)
Tungsten fluoride (WF₆), Tungsten chloride (WC
l₆), Alkyl aluminums ((CH_Three)_TwoAlH,
(CH_Three)_ThreeAl, (i-C_FourH₉) _ThreeAl, (CH_Three)_TwoA
ICl, (CH_Three)_ThreeNAlH_ThreeEtc.), C₇H₇F₆O_TwoA
u, Mo (CO₆), Fe (CO)_Five, Ni (CO)_Four,
Cu (hfac)_Two, Cr (C ₆H₆)_Two, C_FiveH_FivePt (C
H_Three)_ThreeAnd the like.

The type and amount of the additive substance are appropriately set in consideration of the fact that the selective film-forming material selected has a high electron scattering ability and an appropriate electron absorption. Needless to say, it is preferable that the metal compound is stable and is a safe substance for safety and health.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

(Embodiment) First, p having a resistance value of 4 to 6 ohms
A membrane having a thickness of about 1 to 3 μm was formed in an 8-inch silicon wafer of a mold. A reticle pattern was formed on the membrane by a reactive ion etching method by applying a photolithography method to produce a scattering stencil type reticle.

Then, regarding this reticle pattern,
Inspection of pattern accuracy such as pattern position and pattern size, and pattern defects such as defective connection and disconnection were performed. The inspection was performed using a mask defect device equipped with an ion beam column and an electron beam column. Regarding pattern defects, defective portions were detected by superimposing a morphological image of a reticle pattern actually manufactured on a pattern design drawing. As a result, as shown in FIG. 2, a so-called white defect pattern 9 was detected, which was missing in the reticle pattern 8 having a cross shape formed on the membrane portion 7a of the reticle 7.

Therefore, selective film formation was performed in the vicinity of the white defect pattern 9 using a focused ion beam of gallium ions as an excitation source. As the material, tetramethylsilane and C ₅ H ₅ Pt (CH ₃ ) ₃ were mixed and used.

The two substances are both liquid at room temperature and are difficult to react with each other or alone in the gas phase. Therefore, they are mixed in the same vessel and then gasified and supplied near the sample. did. FIG. 1 is a schematic view of a focused ion beam apparatus provided with the gas supply system and intended for correcting white defects.

The above two types of gases are put into the container 1 and turned into a uniform mixed gas by a sufficient stirring process. Thereafter, the container 1 is closed and the pressure is reduced to about the same level as the vacuum chamber 4.
The mixed gas in the container 1 passes through a pipe 2 and passes through a vacuum chamber 4
Introduced inside. The vacuum chamber 4 is appropriately heated with a hot plate or the like in order to maintain an appropriate vapor pressure of the mixed gas. Further, it is necessary to perform substantially the same heating on the pipe 2 disposed up to the vicinity of the substrate 7 mounted on the mounting table 6 in the vacuum chamber 4. In this example, the container 1 was heated to about 56 ° C, and the pipe 2 was heated to 45 to 50 ° C. The amount of gas supplied to the vicinity of the substrate depends on the vapor pressure.

Thus, the mixed gas is supplied from the container 1 to the vicinity of the substrate 7 in the vacuum chamber 4 via the pipe 2.
At this time, the flow rate of the mixed gas is adjusted by a mass flow controller (MFC) 3 installed in the pipe 2. The mixed gas supply region is irradiated with a focused ion beam from a beam source 5 installed at the top of the vacuum chamber 4. Specifically, a white defect portion of a substrate (reticle pattern) to which the mixed gas was supplied was irradiated with a focused ion beam made of Ga ions while scanning. The acceleration voltage at that time is 30 kV
And the beam current was 400 pA. The white defect part was about 0.15 μm × 0.20 μm, and it took less than two minutes to form a film on this part.

After confirming that all the pattern defects were corrected by the same inspection as that performed after the reticle was manufactured, the reticle was set in an electron beam reduction projection exposure apparatus and lithography was performed. Specifically, the electron beam was accelerated to 100 kV, and the beam current was about 20 μA. Lithography was performed on a high-resolution, high-sensitivity positive electron beam photosensitive resist ZEP520 (manufactured by Zeon Corporation) having a thickness of about 0.3 μm on a 4-inch wafer. Processing after resist application (prebaking, development conditions) and the like were made normal conditions.

Next, the morphological evaluation and the length measurement evaluation of the resist image were performed with a scanning electron microscope for length measurement. As a result, it was found that the pattern-corrected portion formed a good transfer image similarly to the non-corrected portion, and had the same line width. As a result of the length measurement evaluation, all the patterns were within an error range of 10 nm or less at 3σ with respect to the design value, and it was confirmed that the specifications were sufficiently cleared.

In the above embodiment, the case where a plurality of material gases are mixed in advance and this mixed gas is supplied to the white defect pattern portion has been described, but the plurality of material gases have high reactivity. In addition, when a chemical bond is formed with another material and the material is gasified as it is and the material gas cannot be supplied to the vicinity of the sample, each material is gasified in the containers 10 and 12 as shown in FIG. In advance, the flow rate may be adjusted by the MFC 11 and supplied to the vicinity of the substrate 7.

When a plurality of materials do not react with each other either alone or when a plurality of materials are mixed, as shown in FIG. In section 15, the mixture is gasified as it is,
The flow rate may be adjusted by the MFC 11 and supplied to the vicinity of the substrate 7.

The present invention is not limited to the above embodiments, but can be implemented with various modifications. For example, the materials and dimensions in the present embodiment can be changed and implemented without departing from the gist of the present invention.

[0044]

As described above, according to the method of repairing a scattering stencil type reticle of the present invention, a repair film having characteristics equivalent to those of a reticle electron scatterer can be obtained, thereby providing a high-quality electron beam reduction projection. A scattering stencil-type reticle can be made.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a focused ion beam apparatus provided with a gas supply system used in the method of the present invention.

FIG. 2 is a diagram showing a defect pattern portion of the scattering stencil type reticle according to the present invention.

FIG. 3 is a schematic view showing another example of a focused ion beam apparatus provided with a gas supply system used in the method of the present invention.

FIG. 4 is a schematic view showing another example of a focused ion beam apparatus provided with a gas supply system used in the method of the present invention.

[Explanation of symbols]

1, 10, 12 to 14 Container 2 Piping 3, 11 MFC 4 Vacuum chamber 5 Beam source 6 Mounting table 7 Reticle 7a Membrane 8 Reticle pattern 9 White defect pattern 15 Mixing unit

Claims (5)

[Claims] 1. A method for correcting a defect generated at the time of manufacturing a reticle having a pattern transfer portion formed of an electron beam scatterer and used for transferring a reduced projection transfer image onto a transfer target substrate. A plurality of gaseous substances constituting the electron beam scatterer are supplied to the defect portion in a mixed state at a desired mixing ratio, and an excitation source of any one of a focused ion beam, an electron beam, and a microplasma is supplied. A method for correcting a scattering stencil-type reticle, wherein a film is selectively formed on the defective portion by using the method. 2. A method for correcting a defect generated at the time of manufacturing a reticle having a pattern transfer portion constituted by an electron beam scatterer and used for transferring a reduced projection transfer image onto a transfer target substrate. By supplying a plurality of substances constituting the electron beam scatterer to the defect portion alone in a gasified state, the vicinity of the defect portion is set to a material gas atmosphere having a desired concentration and a mixed composition ratio, and converged ions are formed. A method for repairing a scattered stencil type reticle, wherein a film is selectively formed on the defect portion using any one of an excitation source of a beam, an electron beam, and a micro-plasma. 3. A method for correcting a defect generated at the time of manufacturing a reticle having a pattern transfer portion formed of an electron beam scatterer and used for transferring a reduced projection transfer image onto a transfer target substrate. Then, a plurality of substances constituting the electron beam scatterer are mixed at a predetermined mixing ratio, and the mixed substance is supplied to the defect portion, and any one of a focused ion beam, an electron beam, and a microplasma is excited. A method for repairing a scattering stencil type reticle, wherein a film is selectively formed on the defect portion using a source. 4. The method according to claim 3, wherein the plurality of mixed substances are gasified. 5. The method according to claim 3, wherein the plurality of substances are mixed in advance so that the mixed substance supplied to the defective portion has a desired concentration and a mixed composition ratio. To correct the scattering stencil-type reticle.