JPH0613295A - X-ray mask missing defect repair method and X-ray mask with missing defects repaired - Google Patents

Abstract

(57) [Abstract] [Purpose] The defect of the X-ray shielding weight metal pattern of the X-ray exposure X-ray mask in which the X-ray shielding weight metal pattern is formed on the X-ray transparent thin film can be easily repaired. To do so. [Structure] An X-ray exposure X-ray mask in which an X-ray shielding weight metal pattern is formed on an X-ray transmissive thin film, is formed at an X position at a defect position.
The pattern made of the radiation transparent material is formed to have a thickness such that the contour boundary thereof substantially coincides with the X-ray shielding weight metal pattern and the phase is inverted while passing through the pattern made of the radiation transparent material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for correcting defects in an X-ray mask for transferring a fine pattern in a semiconductor integrated circuit or the like onto an exposed substrate such as a semiconductor wafer by using soft X-rays. And an X-ray mask with a corrected defect.

[0002]

2. Description of the Related Art The X-ray exposure method for transferring a fine pattern such as an integrated circuit on an X-ray mask onto a substrate to be exposed such as a semiconductor wafer using a soft X-ray having a wavelength of several A to several tens of A is the minimum. Since it has a high resolution capable of transferring even a fine pattern having a size of 0.2 μm or less, it is expected to be suitable for pattern transfer when mass-producing super LSIs and the like.

An X-ray mask used for X-ray exposure is a thin film having a certain transmittance for X-rays used for exposure, and a fine pattern is formed by a light-shielding substance such as a heavy metal that does not easily transmit X-rays. It has a different configuration.

FIG. 12 is a schematic sectional view showing a typical X-ray mask.

The X-ray mask shown in FIG. 12 is a mask substrate 1
An X-ray transmissive thin film 19 is deposited on the surface of No. 8, and an X-ray shielding weight metal pattern 20 is arranged on the X-ray transmissive thin film 19. Further, the central portion of the back surface of the mask substrate 18 which is not protected by the thin film 21 is locally removed, so that the X-ray transparent thin film 19 and the X-ray shielding weight metal pattern formed thereon are formed. The part where only 20 is present is formed. This portion is the effective portion of the X-ray mask used for exposure.

Many X-ray masks are attached to the frame 22 in order to be carried by an exposure operator or to be conveniently transported by an exposure apparatus or the like.

In using the X-ray mask, the exposed substrate coated with a material having photosensitivity to X-rays is brought close to or in close contact with the side of the X-ray mask where the X-ray shielding weight metal pattern 20 is present. When irradiating X-rays from the side opposite to the X-ray shielding weight metal pattern 20 side, the exposed substrate is
Only the photosensitive material in the place where the light-shielding weight metal pattern 20 is not exposed is exposed, and in the place where the X-ray light-shielding weight metal pattern 20 is placed and is in the shadow, the arrival amount of X-rays is small. do not do.

Therefore, if the photosensitive material of the substrate to be exposed is developed, the shape of the X-ray shielding weight metal pattern 20 is transferred to the photosensitive material on the substrate to be exposed at a size ratio of about 1: 1. It Therefore, for example, in order to obtain a fine transfer pattern having a line width of 0.2 μm, the pattern size is slightly changed at the time of transfer, but on the X-ray mask, the line width is about 0.2.
It is necessary to form a pattern for removing or leaving the X-ray shielding material of μm.

By the way, in such X-ray proximity exposure,
The minimum pattern size that can be transferred is mainly determined by the following two conditions.

First, the X-rays are X-ray shielding light weight metal patterns 2.
It is a phenomenon that the light is diffracted to the back side of 0 and the light shielding part is blurred. The amount of diffraction increases as the wavelength of X-rays increases and as the proximity gap between the X-ray mask and the exposure target substrate increases, so that the X-rays have a shorter wavelength and the proximity gap between the X-ray mask and the exposure target substrate increases. The smaller is, the higher the resolution is.

Another condition is the range of secondary electrons generated when X-rays are captured by a material coated on the substrate to be exposed and having photosensitivity to the X-rays.

The mechanism of exposure by X-ray exposure is a mechanism in which a photosensitive material is chemically changed by secondary electrons generated when X-rays are taken into a material having sensitivity to X-rays. Is said to be, and
No matter how narrow the X-rays are applied, if the secondary electrons fly far, the photosensitive range is widened and fine patterns cannot be formed.

The range of secondary electrons is related to the energy of the irradiated X-rays, that is, the wavelength of the X-rays, and the higher the energy, and therefore the shorter the wavelength, the larger. In addition, since the range of secondary electrons has a stochastic distribution, the absolute number of secondary electrons that fly to a predetermined distance increases according to the X-ray irradiation dose. Therefore, the X-ray irradiation dose indirectly contributes to the resolution.

As described above, considering diffraction, it is preferable that X-rays have a short wavelength, and considering the range of secondary electrons, it is preferable that X-rays have a long wavelength. Then, there is an X-ray wavelength band that is most convenient for obtaining the highest resolution, and considering the realistic gap between the X-ray mask and the substrate to be exposed and the exposure amount, the X-ray has several wavelengths. A to 10 or more A
Is optimal.

The required thickness of the heavy metal pattern having a light-shielding property for controlling the transmitted X-ray dose for X-rays in such a wavelength band to be a fraction of the irradiation dose or less depends on the kind of metal, It becomes 0.5 to 1 μm.

Recently, the size of the X-ray shield pattern is 0.
A value of 2 μm or less is required, and the dimensional accuracy is X
A value such as a fraction of the line shield pattern or less is required, and the required thickness of the X-ray shield weight metal pattern is considerably large when compared with such a pattern line width or its control amount. Is the amount.

Therefore, it is very difficult to process the light-shielding weight metal pattern of the X-ray mask, and a high-level technique is required to obtain a light-shielding weight metal pattern having highly accurate dimensions.

There are roughly two methods for producing the light-shielding weight metal pattern of the X-ray mask.

One of the methods is to attach a light-shielding weight metal film to the entire surface of the X-ray transparent film of the X-ray mask substrate, apply a resist to the light-shielding weight metal film, and apply an electron beam drawing method to it. , A light-shielding weight metal film is formed by dry-etching the light-shielding weight metal film based on the resist pattern.

In this case, it is considerably difficult to dry-etch the light shielding metal film directly by using the resist pattern as an etching mask because the resist has a low resistance as an etching mask.

Therefore, a film having a higher etching resistance to the light-shielding weight metal than the resist, such as silicon dioxide, is provided on the light-shielding metal film, and the resist pattern is formed on the silicon dioxide film. And then at
In many cases, the resist pattern is used as an etching mask to dry-etch a film of silicon dioxide or the like, and the resulting pattern of silicon dioxide or the like is used as an etching mask to dry-etch the light-shielding metal film.

Another method of forming the light-shielding weight metal pattern of the X-ray mask is as follows. A thin plating base film for plating the light-shielding weight metal is thinly formed on the X-ray transparent film, and a resist is applied thereon. Then, a pattern is formed by an electron beam drawing method or the like, and then, the resist pattern is used as a female mold for plating, and the light-shielding weight metal is plated on the plating base film. This is a method of forming a light-shielding weight metal pattern by.

Before forming the resist pattern described above, X such as silicon dioxide is formed on the plating base film described above.
An X-ray transparent film such as silicon dioxide can be obtained by forming a resist pattern on the X-ray transparent film such as silicon dioxide by applying a film having a line-transparent property in advance and performing dry etching using the resist pattern as an etching mask. The material pattern is formed, and then the X-ray shielding weight metal pattern is formed on the plating base film using the X-ray transmitting material pattern such as silicon dioxide as a female die for plating to form the X-ray shielding weight metal pattern. There is also a method.

Whichever of the above-mentioned methods for forming the X-ray shielding weight metal pattern is adopted, it is possible to form the X-ray shielding weight metal pattern having a line width of 0.2 μm or less in a thickness of 0.5 to 1 μm. ,very hard.

In particular, in the above-mentioned plating method, when the size of the recess of the plating female die formed of an X-ray transparent material such as resist or silicon dioxide is about 0.2 to 0.3 μm, the plating metal is formed in the recess. It becomes difficult to enter, and the depth is
Plating becomes difficult at a depth of 0.5 to 1 μm.

As described above, even if the X-ray shielding weight metal pattern is formed on the flat X-ray transparent film under substantially uniform conditions, it is very difficult and is accompanied by high technology. On the other hand, when the X-ray shielding weight metal pattern formed as described above has a defect that is missing for some reason, it is necessary to attach a very thick pattern that is fine and highly accurate only to the position of the defect. , Extremely difficult.

Unlike the case where the X-ray shielding weight metal pattern is made from the beginning, when the X-ray shielding weight metal pattern for attaching the defect is attached under the condition that the X-ray shielding weight metal pattern already exists, the X-ray shielding weight metal pattern is applied to the entire surface. Since it is not possible to attach the X-ray shielding weight metal film, it is impossible to add the X-ray shielding weight metal pattern for defect correction by the dry etching method described above.

On the other hand, a coating which can be peeled off without damaging the X-ray shielding weight metal pattern is formed on the X-ray shielding weight metal pattern, and the defective portion of the X-ray shielding weight metal pattern is locally removed. Then, it is conceivable that the X-ray shielding weight metal is deposited only on the defective portion where the X-ray shielding weight metal pattern is missing by vapor deposition, sputtering, chemical vapor deposition or the like.

However, the method of preliminarily forming such a female die and then applying the X-ray shielding weight metal by means other than plating is not used as an X-ray mask making method. It is more difficult for X-ray shielding weight metal to adhere to the concave portion than in the case of plating.

In the case of plating as well, even when a plating female die is formed on a flat surface, when a pattern line width of 0.2 to 0.3 μm is reached, it is not possible to plate a recess having a depth of 0.5 to 1 μm. On the other hand, the X-ray shielding weight metal pattern has a level difference of 0.5 to 1 μm, and a film is further applied to cover the level difference to locally open only the minute missing defect portion, which is extremely difficult. It is currently impossible to deposit X-ray shielding weight metal in very deep fine grooves.

As a method of repairing a reticle or mask for light exposure, it is possible to repair a missing defect of the light shielding pattern by ionizing a light shielding metal and flying it to the site of the defective defect of the light shielding pattern. Currently in use.

However, according to such a deposition method, a pattern of the X-ray shield metal whose thickness (height) is 2 to several times larger than the line width is applied to the X-ray shield weight metal by dry etching or plating. It is very difficult to form a pattern with an accuracy of a fraction of the line width or less, which is comparable to the pattern formation.

When an X-ray shield metal pattern is to be formed using an ion beam, the ion beam should be narrowed so that its dimension is equal to or less than the line width of the pattern to be irradiated. Therefore, it is necessary to deposit the X-ray shield metal without increasing or decreasing the line width by the irradiation of the ion beam.

However, it is extremely difficult to deposit the X-ray shield metal on the height of 2 to several times the line width without increasing or decreasing the line width. Generally, in order to form the X-ray shield metal pattern so as not to fall down, the width of the bottom of the pattern must be wide and the width is so narrow that it accumulates on the top. Therefore, the X formed by dry etching or plating is used. Vertical sidewall x-ray shield metal patterns, such as the line shield weight metal pattern, are not available.

Even if the X-ray shield metal pattern is obtained, the unevenness on the side surface is far worse than the X-ray shield weight metal pattern formed by dry etching or plating.

Further, in the formed X-ray shield metal pattern, voids are easily formed, and even if the voids are not formed, the texture of the X-ray shield metal to be deposited is such as vapor deposition, sputtering or plating. Compared to the metal structure formed under favorable conditions, it is rough and has a low density, so that the X-ray shielding property is poor. Therefore, it is necessary to form an X-ray shield metal pattern that is thicker than a good quality X-ray shield metal pattern. This further impedes the formation of a highly accurate defect repair pattern.

[0037]

DISCLOSURE OF THE INVENTION The present invention provides a method for easily forming a repairing pattern having an excellent X-ray shielding function in a missing portion of an X-ray shielding weight metal pattern, and the repaired method. It is intended to provide an X-ray mask having a pattern.

[0038]

In the present invention, as the X-ray shield, a heavy metal having an X-ray shielding property is not used as in the conventional case, but an X-ray shield having a predetermined thickness is formed.
A contour boundary portion of a pattern made of a line transparent material is used.

On the X-ray transparent thin film of the X-ray mask, an X-ray transparent material is added in an X-ray according to the wavelength of the X-ray used for exposure.
The pattern is formed by depositing the linearly transparent material in such a thickness that the phase is substantially inverted when transmitting the material.

By doing so, the X-rays passing inside the contour of the formed X-ray transparent material pattern and the X-rays passing outside the contour of the pattern are formed.
A line is a portion that has passed through a pattern of an X-ray transmissive material and has almost the same intensity and opposite phases.

Therefore, at the contour boundary of the pattern of the X-ray transparent material, adjacent X-rays having different phases cancel each other out, and the X-ray intensity becomes extremely small. Therefore, when the substrate to be exposed is brought close to the X-ray mask and the X-ray is irradiated, the portion corresponding to the contour boundary of the pattern of the X-ray transmissive material has a light-shielding body having an inherent X-ray shielding property. It is not exposed though it is not used. That is, the contour boundary of the pattern of the X-ray transparent material plays the same role as the X-ray shielding weight metal pattern.

The present invention takes advantage of this fact to form a pattern with an X-ray transparent material in a defective portion where the X-ray shielding weight metal pattern is missing, and the X-ray is formed by the contour boundary of the pattern of the X-ray transparent material. Make sure to repair the defective part where the light shield metal pattern is missing.

[0043]

[Operation] X that the phase of X-ray is almost inverted
An exposure target substrate coated with a material having photosensitivity to X-rays such as a resist is brought close to an X-ray mask having a defect repairing pattern formed of a line-transmissive material, and the same exposure as in a usual case is performed. The material having photosensitivity to X-rays on the substrate to be exposed is not exposed in the place where the X-ray shielding weight metal pattern exists and in the portion corresponding to the contour boundary of the defect repairing pattern formed of the X-ray transparent material. . Therefore, the synthesized pattern is transferred.

Since the portion corresponding to the contour boundary of the defect repairing pattern formed of the X-ray transparent material is arranged in the missing defect portion of the X-ray shielding light weight metal pattern, the missing defect portion is filled with the light shielding body as if it were. A pattern similar to that of can be transferred.

Since the light-shielding portion is not the pattern itself formed of the X-ray transparent material but the contour boundary of the pattern, the light-shielding portion which is very thin and has a high X-ray shielding ability is provided with missing defects. It can be obtained as a light-shielding part to be repaired,
Therefore, it is possible to easily repair the minute defect of the X-ray shielding weight metal pattern of 0.2 μm or less.

[0046]

EXAMPLES Examples of the present invention will now be described with reference to FIGS.

First, the X-ray shielding weight metal pattern 1 exists on the X-ray transparent thin film 2 and should be connected as originally shown in FIG. 2, but as shown in FIG. Suppose

The line width of the X-ray shielding weight metal pattern 1 is 0.
The thickness is 2 μm, the material is tantalum, and the thickness is 0.8 μm.

A resist PMMA is formed on the X-ray transparent thin film 2.
(Polymethyl methacrylate) is applied so that the thickness of the defect repaired portion after development is 1.1 μm, and another X-ray mask different from the X-ray mask for which the defect is to be repaired next is applied.
By performing X-ray exposure using a line mask and then developing, the defect correction pattern 3 is changed to an X-ray pattern as shown in FIG.
The light-shielding weight metal pattern 1 is formed so as to match the center of the part which is cut off and missing. In this case, the resist PMMA corresponds to the X-ray transparent material for defect correction described above. In this case, the line width of the defect correction pattern 3 is
It is set to 0.1 μm.

In forming the pattern 3 for defect correction, a fine X-ray shielding ability as shown in Japanese Patent Application No. 2-232787 is used instead of the ordinary X-ray mask shown in FIG. X with a very high X-ray shield line segment pattern
If the line mask is used to perform the exposure using an apparatus for transferring the line segment pattern to the arbitrary position as shown in Japanese Patent Application No. 01-100124 by X-ray exposure transfer, the defect correction pattern 3 can be more easily obtained. Can be formed.

Even if the X-ray shielding weight metal pattern 1 already exists and there is a step, the resist PMMA pattern on the side wall almost vertical can be formed by the X-ray exposure.

When the refractive index of the X-ray transparent material is n and the thickness is t, X-rays of wavelength λ transmitted through the X-ray transparent material,
The phase difference φ with the X-ray that does not pass through and is directly transmitted is φ = 2π · t (1-n) / λ.

The phase of X-rays transmitted through the X-ray transparent material is
The condition for φ = ± π in order to reverse the phase of the X-ray that does not pass through and is directly transmitted is 2t (1-n) = ± λ, so t = ± λ / 2 (1-n ).

The wavelength λ of the resist PMMA is 0.9 nm.
Since the refractive index n of X with respect to X-rays is n = 0.9996, the phase difference φ with respect to X-rays with λ of 0.9 nm is φ.
Is π, the thickness t of the resist PMMA is t = 1.1 μm, which is the same as the value of 1.1 μm described above.

Thus, if a boundary in which the phase of X-rays differs by π is made by the X-ray transparent material in this way, when irradiating X-rays, the X-ray intensities are almost equal and opposite in phase on both sides of the boundary just described. Become. Therefore, on the boundary described above, X-rays having opposite phases cancel each other out, and the X-ray intensity is always extremely weaker than that of other X-ray transmitting portions.

X on which the above-described defect correcting pattern 3 is formed
An exposed substrate coated with a material having a sensitivity to X-rays such as a resist is brought close to a line mask, and synchrotron radiation X-rays, plasma X-ray sources, electron beam excitation type X-ray sources, etc. Exposure is performed by irradiating X-rays from an X-ray source.

By doing so, the shadowed portion of the X-ray shielding weight metal pattern 1 is not exposed. In addition, the X-ray intensity is also low at the location corresponding to the contour boundary of the defect correction pattern 3 and is not exposed.

At the location corresponding to the contour boundary of the defect repairing pattern 3, the side wall of the defect repairing pattern 3 is formed vertically, and the X-ray mask and the substrate to be exposed are in contact with each other, and the X-rays are perpendicular to them. If is irradiated, a pattern with an infinitely small line width should be created. However, in reality, the side wall which is the contour boundary has an inclination and a surface roughness, and the irradiated X-rays also have a divergence angle, so that the X-ray mask and the substrate to be exposed are not in close contact with each other. Since the exposure is performed with a close gap, the line width does not become an infinitely small line width pattern, but the line width changes depending on the exposure conditions such as the exposure amount and the close gap between the X-ray mask and the substrate to be exposed. Therefore, the line width to be transferred can be controlled by the inclination angle of the side wall of the defect correction pattern 3, the exposure amount, the proximity gap between the X-ray mask and the substrate to be exposed, and the like.

Therefore, if the line portion having a width of 0.1 μm is not exposed along the contour boundary of the defect repairing pattern 3, the line width of 0. A pattern with a line width of 0.2 μm is formed by connecting 1 μm patterns, and as a result, a pattern with a line width of 0.2 μm that is continuous with the pattern formed by the X-ray shielding weight metal pattern with a line width of 0.2 μm is obtained. You can

FIG. 4 shows a line width of 0.1 μm in this way.
The defect correction pattern 3 in the front view of FIG. 1 for more clearly explaining the reason why the pattern having a line width of 0.2 μm is transferred to the defect correction pattern 3 made of the X-ray transparent material. 2 is a cross-sectional view taken along the line AA of FIG. In addition, in order to facilitate understanding, FIG. 4 does not display the X-ray shielding weight metal pattern 1 visible behind, and also shows the X-rays 4 to be emitted,
The front view of FIG. 1 has an upside-down relationship.

As shown in FIG. 4, when the X-ray 4 is incident on the defect-correcting pattern 3 made of an X-ray transparent material through the X-ray transparent thin film 2, the phase of the X-ray becomes defective. Since the correction pattern 3 is inverted, the intensity of the transmitted X-ray becomes minimum at the boundary. In the case of this example, since the line width of the defect repairing pattern 3 is as small as 0.1 μm, the intensity of the X-rays at the center of the line width is smaller than that at a position sufficiently distant from the boundary of the defect correcting pattern 3. , Quite low. Therefore, if the portion where the defect repairing pattern 3 does not exist is exposed and the portion where the X-ray intensity at the center of the line width is maximum is exposed with an exposure amount, the boundary on both sides of the defect repairing pattern 3 is exposed. The patterns that can be formed are connected and transferred as a single line. Therefore, the pattern line width formed on the contour boundary of the defect correction pattern 3 is 0.1 μm.
Therefore, if the conditions for controlling the line width of the defect correction pattern 3 such as the exposure amount are set, two 0.1 μm lines are connected and a 0.2 μm line is transferred. To be done.

From the above, a material having sensitivity to X-rays such as a resist on a substrate to be exposed is formed with a pattern in which a portion corresponding to a missing defect of the X-ray shielding weight metal pattern 1 is repaired. be able to.

Depending on the type of the material having photosensitivity to X-rays, the pattern of the material having photosensitivity to X-rays may be left only in the photosensitized portion during development. Alternatively, the pattern may be formed by removing the material having X-ray sensitivity.

In addition, even in the portion where the defect correcting pattern 3 is placed on the X-ray shielding weight metal pattern, the same operation is performed as to the exposure X-ray passing only the thickness of the defect correcting pattern. can get.

However, this portion does not affect the pattern formed on the exposed substrate because the X-ray is originally shielded by the X-ray shielding weight metal pattern. That is, even if the defect repairing pattern 3 is formed by overlapping the X-ray shielding weight metal pattern portion with the overlap, the X-ray shielding weight metal pattern is overlaid.
The overlapped part does not cause any adverse effects.

Further, in order to form a light-shielding portion for repairing defects in a thicker line width and wider region, a similar defect correction pattern 3 having a line width of 0.1 μm and 0.1 μm is used.
It may be arranged arbitrarily close to each other at an interval of m or less.

In the above description, the case of repairing a defect has been described with an example of a pattern having a line width of 0.2 μm. However, according to the size of the defect to be repaired, the contour boundary of the defect repairing pattern 3 is set. It goes without saying that the line width of the formed pattern may be larger or smaller than 0.1 μm described above.

The arrangement interval in the case of forming a light-shielding portion for repairing a defect in a thick line width and a wide region is also an interval smaller than the line width depending on the line width of the pattern formed on the contour boundary of the defect correction pattern 3. It is also clear that they only need to be placed in close proximity. That is, the line width and the interval of the defect correction pattern 3 formed of the X-ray transparent material such as PMMA described above are
It may be appropriately determined in consideration of the size of the contour boundary line transferred at the time of transfer. In other words, the contour boundary line of the defect correction pattern 3 is transferred under the exposure condition (exposure amount, proximity gap between the X-ray mask and the substrate to be exposed) for transferring the original X-ray shielding weight metal pattern with a regular dimension. The size and the layout of the defect correction pattern 3 are determined in consideration of the size of the pattern.

The conditions under which the adjacent contour boundary lines of the defect correction pattern are transferred without being separated from each other when it is desired to cope with a defect having a wide line width and a wide area are also the above-mentioned exposure conditions (exposure amount, X-ray). It depends on the proximity gap between the mask and the substrate to be exposed. For example, when the proximity gap between the X-ray mask and the substrate to be exposed is 40 to 50 μm, a continuous light-shielding portion can be obtained even if the line width and the interval of the defect correction pattern are about 0.2 μm.

In the above description, the defect correction pattern 3 is
Although it has been shown that PMMA is used as the X-ray transparent material and is formed by X-ray exposure, the type and method of making the X-ray transparent material may be arbitrary.
Of the X-ray transmissive material remaining as
However, it suffices to satisfy a relationship close to 2t (1-n) = ± λ with respect to the wavelength λ of X-ray used for exposure.

Of course, φ-MAC, FBM-G, EX
It is possible to apply any X-ray exposure resist such as P.

Further, a multilayer resist structure is formed, and a pattern is formed on the upper layer resist by electron beam drawing, ion beam drawing, X-ray exposure, light exposure, etc., and the resist or resin of the lowermost layer is shown in FIG. It may be formed as described above.

X-ray shielding weight X on the side where the metal pattern is present
If a pattern that corrects defects is formed with a linearly transparent material, X
As shown in FIG. 1, the thickness of the X-ray transparent material changes according to the step created by the X-ray shielding weight metal pattern near the boundary of the defective X-ray shielding weight metal pattern, and the X-ray phase change. In some cases, the amount deviates from an appropriate value, and the light-shielding effect on the contour boundary of the defect correction pattern made of the X-ray transmissive material becomes weak.

To prevent this, as shown in FIG. 5, the X-ray shielding weight metal pattern 1 of the X-ray transparent thin film 2 of the X-ray mask is used.
The defect repairing pattern 5 made of an X-ray transparent material may be provided on the surface opposite to the side on which the defect exists.

Further, as shown in FIG. 6, X of the X-ray mask
On the side where the X-ray shielding weight metal pattern 1 on the X-ray transparent thin film 2 is present, a film 6 of X-ray transparent material such as silicon dioxide or silicon glass for reducing steps is attached, and X A defect correction pattern 7 made of a linearly transparent material may be provided.

In the above description, the patterns 3, 5 and 7 made of the X-ray transparent material formed for defect correction are
The case where only the pattern part is left and the pattern is left is described.

However, in the present invention, since the light-shielding portion formed on the contour boundary of the defect-correcting pattern is used, conversely, the defect-correcting pattern made of the X-ray transmissive material should not be present in that portion, that is, Obviously, it is also possible to use the removal pattern.

FIG. 7 shows an example in which the defect-correcting pattern shown in FIG. 1 is used as an extraction pattern, and an X-ray transparent thin film 2 having an X-ray shielding weight metal pattern 1 is coated with a coating 8 of an X-ray transparent material. Are attached to form a defect-correcting removal pattern 9 on the film 8 of the X-ray transparent material.

FIG. 8 shows an example in which the defect repairing pattern described above with reference to FIG. 5 is used as a removal pattern, and is on the surface opposite to the side where the X-ray shielding weight metal pattern 1 is present on the X-ray transparent thin film 2. To
A film 10 made of an X-ray transparent material is attached to form a defect-correcting removal pattern 11.

As shown in FIG. 9, as in the case of FIG.
On the side of the X-ray transparent thin film 2 of the X-ray mask where the X-ray shielding weight metal pattern 1 is present, a coating 12 of an X-ray transmitting material for reducing the step of the X-ray shielding weight metal pattern 1 is deposited. The defect correction step pattern 13 may be provided in the coating 12 of the X-ray transparent material at a depth at which the X-ray phase is just inverted.

Although the description of FIGS. 5 to 9 does not show the details of the method of forming the defect correction pattern and the material, it is clear that the same method and material as those described in FIG. 1 may be used.

By forming a defect correction pattern with a resist, it peels off when the X-ray mask is washed,
It dissolves.

Therefore, when cleaning the X-ray mask, peeling,
An X-ray transparent material that is not dissolved and is an inorganic film such as silicon dioxide, silicon nitride, boron nitride, or silicon glass, or a polymeric material that is stable against chemicals such as polyimide,
Deposited to a thickness where the phase of transmitted X-rays is almost reversed,
A resist pattern is formed on the film of the arbitrary X-ray transparent material by X-ray exposure, light exposure, electron beam drawing, etc., and the resist pattern is used as an etching mask.
The pattern may be converted (formed) into a pattern of an X-ray transparent material by dry etching and used as a defect correction pattern.

The thickness of the defect correction pattern described above can be inverted in phase only for X-rays having a specific wavelength.

However, even if the phase is not exactly inverted by 180 degrees, it is possible to reduce the intensity of X-rays at the boundary portion of the defect correction pattern according to the degree of change of the phase.

Therefore, even when exposure transfer is performed by X-rays having a continuous wavelength distribution, such as X-rays of synchrotron radiation or X-rays from a plasma X-ray source, the exposure and transfer are performed in the vicinity of the center wavelength of the X-rays used. So that the phase is inverted 180 degrees,
The present invention can be applied by setting the thickness of the X-ray transparent material of the defect correction pattern.

In the above description, the X-ray transparent thin film 2 is used.
An example of forming a pattern for defect correction on one of the surfaces is shown.

However, it is apparent that the defect correcting patterns may be appropriately arranged on both surfaces of the X-ray transparent thin film 2.

When defect-correction patterns are formed on both surfaces of the X-ray transparent thin film 2, the light-shielding portions at the contour boundaries of the defect-correction patterns on the respective surfaces act independently of each other, and one of either surface If the pattern for defect correction is shielded from light, the exposed substrate is not exposed. If a defect repairing pattern is formed so as to intersect one surface of the X-ray transparent thin film 2, the film thickness may change at the intersection and the defect repairing pattern may be cut off. It is preferable to form the pattern separately on both surfaces of the X-ray transparent thin film 2. In this case, the defect-correcting pattern to be formed may be formed in the same manner on both sides by any one of the methods described above, or the defect-correcting pattern on each surface may be the same as described above. It may be formed by any two separate methods of the embodiments.

In each of the above-described embodiments, the defect correcting pattern is added while the X-ray transparent thin film 2 holding the X-ray shielding weight metal pattern 1 is left as it is.

However, if the thickness of the X-ray transparent thin film 2 is sufficiently thick, a step may be formed in the X-ray transparent thin film 2 and the phase of the transmitted X-ray may be inverted by the step.

That is, if the depth of the step to be formed is h and the refractive index of the X-ray transparent thin film 2 is n, the wavelength X of the transmitted X-ray is λ.
On the other hand, if a step is formed so as to satisfy the relationship of h = ± λ / 2 (1-n), the phase of the transmitted X-ray can be inverted.

In FIG. 10, such a defect correction step pattern 14 is used as the X-ray shielding light weight metal pattern 1 of the X-ray transparent thin film 2.
Shows an example formed on the side where
An example is shown in which the defect correcting step pattern 15 is formed on the side of the X-ray transparent thin film 2 where the X-ray shielding weight metal pattern 1 does not exist.

In some cases, it is obvious that the step may be formed on both sides of the X-ray transparent thin film 2.

Further, the thickness T of the X-ray transparent thin film 2 is set to T = ± λ / 2 (1-n), and the penetrating defect correcting patterns 16 and 17 are formed as shown in FIGS. It is also possible to form and perform defect correction.

In order to form the defect repairing pattern as shown in FIGS. 10 to 13, first, as shown in FIG. 7 or 8, the defect repairing removal patterns 9 and 11 are processed to obtain X-ray transparency. Using the coating 8 or 10 of the material as an etching mask,
The X-ray transparent thin film 2 in a portion corresponding to the defect-correcting removal patterns 9 and 11 was processed, and then X was used as an etching mask.
The coating 8 or 10 of the linearly transparent material may be removed.

The coating 8 of the X-ray transparent material in this case
Although or 10 is an X-ray transparent material for the sake of convenience, any material can be used as long as it can be used as an etching mask for processing the X-ray transparent thin film 2.

However, in the case of forming the defect-correction step pattern 14 or the penetrating defect-correction pattern 16 from the defect-correction removal pattern 9 on the side where the X-ray shielding weight metal pattern 1 exists as shown in FIG. It is necessary that the X-ray shielding weight metal pattern 1 is not etched when the X-ray transparent thin film 2 is etched. Therefore, conversely, X
Since the line-shading weight metal pattern 1 also serves as an etching mask, the defect-correction step pattern 14 and the penetrating defect-correction pattern 16 have the shapes shown in FIGS.

In the above-described embodiment, the case where a part of the contour boundaries on both sides of the long side of the rectangular defect correction pattern is used for repairing a missing defect is shown.

However, it is arbitrary which part of the contour of the defect correction pattern is used as the light shielding part.
The contour boundary part that you do not want to work effectively as a light-shielding part,
The line-shading weight metal pattern 1 may be used so that the light is originally shielded.

Any one of the sides of the contour of the defect correction pattern
It is also possible to use one boundary to repair finer missing defects.

Further, in the above-mentioned embodiment, only one example of the shape of the defect is shown, but it goes without saying that a defect having an arbitrary shape can be corrected.

As shown as an example, it is possible not only to connect the missing portions of the X-ray shielding weight metal pattern 1 but also to add a new portion where the X-ray shielding weight metal pattern 1 is completely omitted.

[0104]

As is clear from the above, according to the present invention, a fine defect-correcting pattern can be formed without using an X-ray shielding weight metal that is difficult to process.
Since the defect repairing pattern is formed by an X-ray transmissive material such as silicon dioxide, silicon nitride, silicon glass, or polyimide, the defect correcting pattern can be easily formed by lithography or dry etching.

Further, not the defect repairing pattern itself but the contour boundary portion thereof plays the role of X-ray shielding, so that an extremely thin X-ray shielding portion can be accurately formed, and even a very fine defect can be formed. It can be corrected with high accuracy.

Further, if a plurality of defect correction patterns are arranged with their contour boundaries adjacent to each other, the intensity of the X-rays in the gaps between the adjacent contour boundaries also becomes low, so that a continuous light-shielding portion can be obtained. Large missing defects of any shape and size can also be repaired.

Further, since there is no particular limitation on the base on which the pattern for defect correction is formed, it can be applied to any X-ray mask regardless of the type of light-shielding metal of the X-ray mask to be applied and the method of making it. can do.

Further, as in the conventional case, the ion beam
When attaching the light shield metal due to the gap, if the defect correction position is misaligned or if there is a dimensional error, the original X-ray shield weight metal pattern that originally exists and the defect correction pattern are both metal. It is extremely difficult to remove the defect correction pattern without damaging the X-ray shielding weight metal pattern. However, in the present invention, the defect-correcting pattern is formed with the resist material, and the defect-correcting pattern is formed as it is or with the resist pattern as an etching mask.
If the defect correction position is misaligned or a dimensional error is likely to occur, use the defect correction pattern that has been attached once with an X-ray transparent thin film supporting the X-ray shielding weight metal pattern or the X-ray shielding weight metal pattern as the base. It can be removed without damage and reformed again.

[Brief description of drawings]

FIG. 1 is a schematic plan view (A) and a front view (B) showing an embodiment of the present invention in which a defect correcting pattern is formed on the same side as an X-ray shielding weight metal pattern.

FIG. 2 is a schematic plan view (A) and a front view (B) for explaining the present invention shown in FIG.

3 is a schematic plan view (A) and a front view (B) for explaining the present invention shown in FIG. 1. FIG.

FIG. 4 is a diagram for explaining the X-ray intensity distribution during exposure in the defect correction pattern portion of the present invention shown in FIG. 1 as seen in the cross section along the line XX of FIG.

FIG. 5 is a schematic front view (A) and a bottom view (B) showing an embodiment in which a defect correction pattern is formed on the side opposite to the X-ray shielding weight metal pattern of the present invention.

FIG. 6 is a schematic linear plan view showing an embodiment of the present invention in which a defect repairing pattern is formed after an X-ray transparent coating is applied to the same side as the X-ray shielding weight metal pattern for flattening. It is a figure (A) and its cross section (B).

FIG. 7 is a schematic plan view (A) and a cross-sectional view (B) thereof showing an embodiment of the present invention in which a defect-correcting punching pattern is formed on the same side as the X-ray shielding weight metal pattern.

FIG. 8 is a schematic cross-sectional view (A) and a bottom view (B) showing an embodiment of the present invention in which a defect correcting punching pattern is formed on the side opposite to the X-ray shielding weight metal pattern.

FIG. 9 is a schematic diagram showing an embodiment of the present invention, in which an X-ray permeable coating is formed on the same side as the X-ray shielding weight metal pattern for planarization, and then a defect-correcting punching pattern is formed. It is a top view (A) and its cross-sectional view (B).

FIG. 10 is a schematic plan view (A) and a cross-sectional view thereof showing an embodiment of the present invention in which a step pattern for defect correction is formed on the same side as an X-ray shielding weight metal pattern of an X-ray transparent thin film. (B).

FIG. 11 is a schematic cross-sectional view (A) and a bottom view showing an embodiment of the present invention in which a step pattern for defect correction is formed on the side of the X-ray transparent thin film opposite to the X-ray shielding weight metal pattern. B).

FIG. 12 is a schematic plan view (A) and its cross section showing an embodiment in which a defect repairing pattern penetrating therethrough is formed from the same side of the X-ray transparent thin film as the X-ray shielding weight metal pattern of the present invention. It is a side view (B).

FIG. 13 is a schematic cross-sectional view (A) showing an embodiment of the present invention, in which a defect repairing pattern penetrating from the side opposite to the X-ray shielding weight metal pattern side of the X-ray transparent thin film is formed. ) And a bottom view (B).

FIG. 14 is a sectional view showing a conventional X-ray mask.

[Explanation of symbols]

1 X-ray shielding weight metal pattern 2 X-ray transmissive thin film 3 Defect repair pattern 4 X-ray 5 Defect repair pattern made of X-ray transmissive material 6 X-ray transmissive material coating 7 Defect made of X-ray transmissive material Repair pattern 8 X-ray transparent material coating 9 Defect repair blank pattern 10 X-ray transparent material coating 11 Defect repair blank pattern 12 X-ray transparent material coating 13 Defect repair step pattern 14 Defect repair step Pattern 15 Defect correcting step pattern 16 Penetrating defect correcting pattern 17 Penetrating defect correcting pattern 18 Mask substrate 19 X-ray transparent thin film 20 X-ray shielding weight metal pattern 21 Thin film 22 Frame

Claims (4)

[Claims] 1. An X-ray mask for X-ray exposure, wherein an X-ray shielding weight metal pattern is formed on an X-ray transmissive thin film, and an X-ray is placed at a defect position where a part of the X-ray shielding weight metal pattern is missing. A pattern is formed by a transparent material, and a part or all of the contour boundary of the X-ray transparent material is aligned with the missing defect position of the X-ray shielding weight metal pattern. The thickness of the pattern made of a conductive material is set so that the phase of X-rays having a wavelength used for exposure is substantially inverted while the X-rays pass through the pattern made of the X-ray transparent material, whereby X-ray shielding light weight At the contour boundary of the pattern made of the above-mentioned X-ray transmissive material existing at the defective position of the metal pattern, the transmitted X-ray intensity at the time of exposure is made lower than other X-ray transmissive portions, On the other hand, the surface of the photosensitive material The coated substrate to be exposed is arranged close to the X-ray mask and irradiated with X-rays, and the pattern on the X-ray mask is transferred onto the substrate to be exposed having the photosensitive material coated thereon by X-ray exposure. At this time, the portion corresponding to the missing defect of the X-ray shielding light weight metal pattern is exposed and transferred by being repaired by the light shielding portion corresponding to the contour boundary of the pattern made of the X-ray transparent material. An X-ray mask missing defect repairing method, comprising: 2. An X-ray mask for X-ray exposure, comprising an X-ray transmissive thin film on which an X-ray shielding weight metal pattern is formed. A pattern is formed by a transparent material, and a part or all of a contour boundary of the pattern made of the X-ray transparent material is made to coincide with a defective defect position of the X-ray shielding weight metal pattern. The thickness of the pattern made of a line-transparent material is such that the phase of X-rays having a wavelength used for exposure is substantially inverted while the X-rays pass through the pattern made of the X-ray transparent material. X-ray mask. 3. An X-ray mask for X-ray exposure, wherein an X-ray shielding weight metal pattern is formed on an X-ray transmissive thin film, wherein the X-ray is located at a defect position where a part of the X-ray shielding weight metal pattern is missing. A step pattern for defect correction is formed on the transparent thin film, and a part or all of the contour boundary of the step pattern has the above X
The light-shielding weight metal pattern is made to match the missing defect position, and the depth of the step pattern is such that the phase of the X-ray of the wavelength used for exposure is substantially inverted depending on the presence or absence of the step. X-ray mask. 4. An X-ray mask for X-ray exposure, wherein an X-ray shielding weight metal pattern is formed on an X-ray transmissive thin film, wherein the X-ray transmissive thin film has a thickness of an X-ray having a wavelength used for exposure. A defect having a thickness that the phase is almost inverted while passing through the X-ray transparent thin film, and a defect penetrating the X-ray transparent thin film at a defect position where a part of the X-ray shielding weight metal pattern is missing X-ray mask, wherein a part of the contour boundary of the penetrating defect correcting pattern is matched with the missing defect position of the X-ray shielding weight metal pattern. .