JPH05206015A - X-ray mask and method of manufacturing the same - Google Patents

Abstract

(57) [Abstract] [Objective] The alignment light that passes through the alignment mark of the X-ray mask and reaches the semiconductor substrate is eliminated to improve the accuracy of positional deviation detection by the first-order reflected diffraction light. An X-ray transmission film 2 made of a SiN film is formed on the surface of a support 1, and an LSI pattern 3 and an alignment mark composed of a convex portion 4a and a concave portion 4b are formed on the surface of the X-ray transmission film 2. 4 are formed. A visible light reflective grating pattern 5 made of a W film is formed on the surface of the convex portion 4a of the alignment mark 4, and a metal film 7 made of a W film is formed on the surface of the concave portion 4b of the alignment mark 4. .. As the laser light 13 does not reach the semiconductor substrate 30 after passing through the alignment mark 4, unnecessary reflection from the semiconductor substrate 30 is detected when the first-order reflected diffracted light 14 from the alignment mark 4 is detected by the photodetector. No light is mixed in.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray mask used in an X-ray exposure method in a semiconductor device manufacturing process and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, as semiconductor devices, especially large-scale integrated circuit (LSI) devices, have been required to have higher density and higher speed, miniaturization of elements has been required, and they are used in a photo-etching process in the manufacturing process thereof. The shorter the wavelength of light, the finer the element can be formed. Therefore, the soft X with a wavelength of around 1 nm
An X-ray exposure method using a light beam (hereinafter, simply referred to as X-ray) as a light source is regarded as a promising next-generation exposure method.

For the X-ray mask used in this X-ray exposure method, a thin X-ray transmission film made of a light element material is used in order to minimize the attenuation that occurs when X-rays pass through.
It is usual to form an X-ray absorption film on the X-ray transmission film, which is made of a heavy metal that absorbs X-rays and forms a transfer pattern (hereinafter referred to as an "absorber pattern") on a semiconductor substrate. is there.

The above-mentioned conventional X-ray mask will be described below with reference to the drawings. FIG. 33 shows a cross-sectional structure of a conventional X-ray mask G. In FIG. 33, 1 is a frame-shaped support made of a Si substrate, 2 is an X-ray transparent film made of a SiN film formed on the surface of the support 1. (Membrane film), 3 is an LSI pattern formed on the surface of the X-ray transparent film 2, and 4 is an alignment mark (positioning mark) formed on the surface of the X-ray transparent film 2. The mark 4 is formed of an X-ray absorber made of a W film.

Explaining the X-ray mask G in detail,
An X-ray transmission film 2 having a film thickness of 2 μm is formed on the surface of the support 1, and an LSI having a film thickness of 0.7 μm is formed on the surface of the X-ray transmission film 2.
The pattern 3 and the alignment mark 4 are formed. Further, the back surface side of the support 1 in the exposed area is etched in order to transmit X-rays.

As the X-ray transparent film 2, a Si film, a SiC film, a diamond thin film, or the like may be used instead of the SiN film, and the LSI pattern 3 and the alignment mark 4 may be replaced with Au film instead of the W film. Other heavy metal thin films such as Ta and Ta may be used.

By the way, in the X-ray exposure method using X-rays as a light source, it is difficult to perform reduction projection exposure because there is no lens capable of condensing X-rays. Therefore, it is necessary to form a fine pattern on the X-ray mask G having the same size as that of the pattern transferred to the semiconductor substrate.

In the X-ray exposure method using such an X-ray mask G, as shown in FIG. 34, the X-ray mask G and the semiconductor substrate 30 having the alignment mark 31 and the resist 32 applied to the surface thereof are provided. Proximity state, for example, about 20 μm apart and facing each other, and after aligning them, irradiating X-rays called synchrotron radiation (SOR) emitted from a storage ring (not shown) and guided by a beam line Is.

As a method of detecting the amount of misalignment between the X-ray mask G and the semiconductor substrate 30 when aligning the X-ray mask G with the above-mentioned X-ray exposure method, a grid-like alignment mark formed on the X-ray mask G is used. 4 and the lattice-shaped alignment mark 31 formed on the semiconductor substrate 30 are simultaneously irradiated with laser light as visible light (alignment light), and the respective reflected diffracted light generated by the laser light is compared. It is used as one of the accurate positioning methods. Hereinafter, this method will be described in more detail.

As shown in FIG. 34, the laser beam 13A emitted from the back side of the X-ray mask G passes through the X-ray transparent film 2 and illuminates the lattice-shaped alignment mark 4,
Since reflected diffracted light is generated, the first-order reflected diffracted light 14 of these reflected diffracted light is reflected by the first photodetector (not shown).
To detect. On the other hand, the laser beam 13B that has passed through the portion of the X-ray transparent film 2 where the alignment mark 4 is not formed and irradiates the alignment mark 11 of the semiconductor substrate 30 produces another first-order reflected diffracted light 15, so that this semiconductor substrate The other first-order reflected diffracted light 15 from the alignment 11 of 30 is detected by the second photodetector.
Alignment mark 1 of semiconductor substrate 30 and first-order reflected diffracted light 14 irradiated with alignment mark 4 of X-ray mask G
By comparing the phase with the other 1st-order reflected diffracted light 15 from 1, the positional deviation between the X-ray mask G and the semiconductor substrate 30 is detected.

[0011]

However, according to the above-described method for detecting the positional deviation using the conventional X-ray mask G, 0 which is transmitted through the alignment mark 4 of the X-ray mask G.
The secondary transmitted diffracted light 16 is reflected by the surface of the semiconductor substrate 30 and irradiates the alignment mark 4 again, and becomes unnecessary diffracted light 17 composed of the primary transmitted diffracted light. This unnecessary diffracted light 17
Is the first-order reflected diffracted light 1 necessary for detecting the positional deviation.
Since the first-order reflected diffracted light 14 and the unnecessary diffracted light 17 overlap and are detected by the first photodetector because they are diffracted in the same direction as 4, the detection error of the first-order reflected diffracted light 14 is large. There is a problem that there is.

Further, according to the conventional X-ray mask G, the detection error is not limited to the 0th-order transmitted diffracted light 16 and the 1st-order transmitted diffracted light 18 or the higher-order transmitted diffracted light (not shown). Can also occur.

In addition, the fact that the transmitted light transmitted through the X-ray transmission film 2 is generated means that the first-order reflected diffracted light 14 used for the position shift detection.
However, the laser light 13 emitted to the alignment mark 4
The light intensity is lower than that of A, and the signal S
There is also a problem that the / N ratio becomes worse.

In view of the above, the present invention provides an X-ray mask in which the first-order reflected diffracted light obtained when the alignment mark of the X-ray mask is irradiated with laser light as visible light is not affected by the transmitted diffracted light. Further, the present invention provides an X-ray mask manufacturing method capable of manufacturing such an X-ray mask easily and reliably.

[0015]

In order to achieve the above object, the inventions of claims 1 to 9 are characterized in that the surface of the alignment mark formed on the surface of the X-ray transparent film is made uneven in cross section. The first-order reflected diffracted light is obtained and the surface of the alignment mark is covered with a visible light transmitting film to prevent visible light from passing through the alignment mark.

[0016] Specifically, the means for solving the problems according to the first aspect of the present invention is that the alignment marks formed on the surface of the X-ray transparent film are alternately formed so that the surface portion of the X-ray transparent film has a plane lattice shape and an uneven cross section. And a visible light reflection film is formed on each surface of the convex portion and the concave portion of the alignment mark.

Further, according to the invention of claim 2, since the cross-section is simply formed on the surface of the X-ray transmissive film in a concavo-convex shape, the concave portion of the alignment mark has a surface portion of the X-ray transmissive film. The alignment mark is formed by denting in a plane lattice shape, and the convex portion of the alignment mark is a flat portion between the concave portions on the surface of the X-ray transparent film.

According to the invention of claim 3, in order to improve the relative position between the alignment mark of the X-ray mask and the LSI pattern, the visible light reflection film on the surface of the convex portion of the alignment mark is formed in the same step as the LSI pattern. To form
The visible light reflection film formed on the surface of the convex portion of the alignment mark is an X-ray absorber.

Specifically, the means for solving the problems according to the fourth aspect of the invention is to form a visible-light-reflective grating pattern in the form of a plane grating composed of a first visible-light-reflecting film on the surface of the X-ray transmitting film, and to form an X-ray. A plane grid-shaped visible light transmitting film is formed on the surface of a portion of the transmitting film where the visible light reflecting grating pattern is not formed, and a second visible light reflecting film is formed on the surface of the visible light transmitting film. The alignment mark formed on the surface of the X-ray transmissive film is composed of a convex portion composed of the X-ray transmissive film and the visible light transmissive film and a concave portion composed of a back side portion of the visible light reflective grating pattern in the X-ray transmissive film. To do.

Further, according to the invention of claim 5, the first visible light reflecting film is formed in the same step as the LSI pattern in order to improve the relative position of the alignment mark of the X-ray mask and the LSI pattern. In addition to the constitution, the constitution that the first visible light reflecting film is an X-ray absorber is added.

[0021] Specifically, the means for solving the problems according to the invention of claim 6 is that the alignment marks formed on the surface of the X-ray transmissive film are made of the X-ray transmissive film and have the same thickness and project toward the front surface side. It is configured by a convex portion having a planar lattice shape and a concave portion that is depressed in a planar lattice shape toward the back surface between the convex portions, and a visible light reflection film is provided on each of the convex portion and the concave portion of the alignment mark. To form.

Specifically, the means for solving the problems according to the seventh aspect of the invention is to form a visible light transmitting grating pattern in the form of a plane grating made of a visible light transmitting film on the surface of the X ray transmitting film, The alignment mark formed on the surface is not formed with the visible light transmissive pattern on the back side of the visible light transmissive pattern on the X-ray transmissive film and the convex portion formed of the visible light transmissive lattice pattern. And a visible light reflection film is formed on the surface of the alignment mark.

Specifically, the means for solving the problems according to the invention of claim 8 is a visible-light-transmissive grating in the form of a plane lattice formed of a visible-light-transmissive film so that the back surfaces of the X-ray-transmissive film are flush with each other. Along with forming the pattern, a grid-like protrusion having a planar grid shape in which the X-ray transparent film projects to the front side is formed on the front side of the visible light transparent grating pattern in the X-ray transparent film, and is formed on the surface of the X-ray transparent film. The alignment mark to be formed is formed by a convex portion formed by the lattice-shaped protrusions of the X-ray transmission film and the visible light transmitting lattice pattern and a concave portion formed by a flat portion in which the lattice-shaped protrusions are not formed in the X-ray transmission film. The visible light reflecting film is formed on the surface of the alignment mark.

The invention of claim 9 prevents the visible light from being reflected between the X-ray transmissive film forming the convex portion of the alignment mark and the visible light transmissive grating pattern. In the structure of 7 or 8, the X-ray transparent film and the visible light transmissive grating pattern are such that the reflectance of visible light at the interface between the X-ray transmissive film and the visible light transmissive grating pattern is smaller than a predetermined value. The configuration that each is made of a material is added.

A tenth aspect of the present invention is the method of manufacturing an X-ray mask according to the first aspect of the present invention, which comprises a step of forming an X-ray transparent film on the surface of the mask support, and a surface of the X-ray transparent film. A step of forming a visible-light-reflective grating pattern in the form of a planar lattice made of a visible-light-reflective film on the X-ray transmitting film, and etching the X-ray transparent film by using the visible-light-reflective grating pattern as a resist mask. On the surface portion of the permeable film, the rear surface side portion of the visible light reflective grating pattern in the surface portion is composed of concave portions which are depressed in a planar lattice shape and convex portions which are flat portions between the concave portions. And a step of forming a visible light reflection film on the surface of the alignment mark.

An eleventh aspect of the invention is a method for manufacturing an X-ray mask according to the fourth aspect of the invention, which comprises the step of forming an X-ray transparent film on the surface of the mask support, and the surface of the X-ray transparent film. A step of forming a visible-light-reflective grating pattern in the form of a plane grid composed of a first visible-light-reflective film, and a planar grating on the surface of the X-ray transparent film where the visible-light-reflective grating pattern is not formed. By forming a visible light-transmitting film having a circular shape, a convex portion formed of the X-ray transmitting film and the visible light transmitting film and a concave portion formed of the back side portion of the visible light reflecting grating pattern in the X-ray transmitting film are formed. It is configured to have a step of forming a configured alignment mark and a step of forming a second visible light reflecting film on the surface of the visible light transmitting film.

A twelfth aspect of the present invention is a method of manufacturing an X-ray mask according to the sixth aspect of the present invention, wherein the mask support is subjected to an etching treatment on the surface where an alignment mark is to be formed. A step of forming a lattice pattern having a plane lattice shape and a concave cross-section on the surface of the body; a step of forming an X-ray transparent film on the surface of the mask support with a substantially uniform thickness; A step of forming a visible light reflection film on a portion where an alignment mark is formed, and removing at least a back side portion of the mask support where a portion where an alignment mark is formed are formed, so that the X-ray transmission films are formed to have the same thickness. An alignment mark composed of a convex portion having a planar lattice shape protruding toward the front surface side and a concave portion concaved in a planar lattice shape toward the back surface between the convex portions. In which a structure including the step of forming.

A thirteenth aspect of the present invention is a method for manufacturing an X-ray mask according to the seventh aspect, wherein the step of forming an X-ray transparent film on the surface of the mask support and the surface of the X-ray transparent film. A step of forming a visible light transmissive film on at least a portion of the alignment mark to be formed, and a visible light transmissive grating pattern of a planar lattice formed of the visible light transmissive film by etching the visible light transmissive film. By forming, the back side portion of the visible light transparent pattern in the X-ray transparent film and the convex portion formed of the visible light transparent grid pattern and the visible light transparent pattern in the X-ray transparent film are formed. The structure includes a step of forming an alignment mark composed of a concave portion formed of a non-existing portion and a step of forming a visible light reflecting film on the surface of the alignment mark. Than it is.

A fourteenth aspect of the present invention is a method for manufacturing an X-ray mask according to the eighth aspect, wherein a visible light transmitting film is formed on at least a portion of the surface of the mask support where an alignment mark is formed, and the flat lattice pattern is formed. And the step of forming an X-ray transparent film on the surface of the mask support so that the X-ray transparent film is formed on the front side of the visible light transparent grating pattern in the X-ray transparent film. A step of forming a lattice-like protrusion having a plane lattice shape in which the film protrudes to the front side, a step of forming a visible light reflection film on a portion of the surface of the X-ray transmission film where an alignment mark is formed, and the mask support By removing at least the back side part of the part where the alignment mark is formed, the grid-like protrusions of the X-ray transparent film and the visible light transparent grid pattern are formed. In which the convex portion and the X-ray transparent film configured to include a step of forming an alignment mark composed of a concave portion composed of a flat part which is not the lattice-shaped protruding portion is formed.

[0030]

According to the structure of claim 1, since the alignment mark is composed of the convex portion and the concave portion in which the surface portion of the X-ray transparent film is alternately formed in a concave-convex cross-section, the visible light irradiated on the alignment mark is 1 The second-reflected diffracted light is generated, and since the visible light reflection film is formed on each surface of the convex portion and the concave portion of the alignment mark, the visible light irradiated on the alignment mark does not pass through the alignment mark.

According to the structure of the second aspect, the concave portion of the alignment mark is formed by denting the surface portion of the X-ray transparent film in a plane lattice shape, and the convex portion of the alignment mark is formed on the surface portion of the X-ray transparent film. Since the flat portion is formed between the concave portions, the alignment mark having a concave-convex cross section can be easily formed on the surface of the X-ray transparent film.

According to the third aspect of the present invention, since the visible light reflecting film formed on the surface of the convex portion of the alignment mark is formed of the X-ray absorber, the visible light reflecting film is formed in the same step as the LSI pattern. Therefore, the accuracy of the relative position of the LSI pattern and the alignment mark can be improved, and the X-ray mask can be manufactured easily and reliably.

According to the structure of claim 4, the visible light reflective grating pattern formed of the first visible light reflective film is formed on the surface of the X-ray transmissive film, and the visible light reflective grating pattern in the X-ray transmissive film is formed. Since the planar grid-like visible light transmitting film is formed on the surface of the non-existing portion, the convex portion made of the X-ray transmitting film and the visible light transmitting film and the concave portion made of the back side portion of the visible light reflecting grating pattern in the X-ray transmitting film are formed. Since and form an alignment mark having a concave-convex cross section, visible light irradiated on the alignment mark produces first-order reflected diffracted light. Further, since the second visible light reflecting film is formed on the surface of the visible light transmitting film, the surface of the alignment mark is formed by the visible light reflecting pattern and the second visible light reflecting film formed on the surface of the visible light transmitting film. Since it is covered, the visible light applied to the alignment mark does not pass through the alignment mark.

According to the structure of claim 5, since the first visible light reflecting film is formed of the X-ray absorber, the visible light reflecting grating pattern can be formed in the same step as the LSI pattern. The accuracy of the relative positions of the alignment marks can be improved, and the X-ray mask can be manufactured easily and reliably.

According to the sixth aspect of the present invention, since the alignment mark is composed of the convex portion formed of the X-ray transparent film and protruding toward the front surface side, and the concave portion concaved to the rear surface side between the convex portion, the alignment mark is formed. Since the cross section of will be uneven,
The visible light applied to the alignment mark generates first-order reflected diffracted light, and the visible light applied to the alignment mark is not visible because the visible light reflecting film is formed on each surface of the convex and concave parts of the alignment mark. It does not pass through the alignment mark.

According to the structure of claim 7, the back side of the visible light transparent pattern in the X-ray transparent film, the convex portion composed of the visible light transparent lattice pattern, and the visible light transparent pattern in the X-ray transparent film are formed. Since the alignment mark is formed by the concave portion including the flat portion that is not present, the cross section of the alignment mark becomes uneven, so that the visible light with which the alignment mark is irradiated produces first-order reflected diffracted light. Further, since the visible light reflecting film is formed on the surface of the alignment mark, the visible light applied to the alignment mark does not pass through the alignment mark.

According to the structure of claim 8, the X-ray transparent film has a grid-shaped protruding portion and a convex portion formed of a visible light-transmitting grid pattern, and a flat portion where the grid-shaped protruding portion of the X-ray transparent film is not formed. Since the alignment mark is formed by the concave portion, the cross section of the alignment mark becomes uneven, so that the visible light irradiated to the alignment mark is 1
Generates secondary reflected diffracted light. Further, since the visible light reflecting film is formed on the surface of the alignment mark, the visible light applied to the alignment mark does not pass through the alignment mark.

According to the ninth aspect of the present invention, since the X-ray transmission film and the visible light transmitting grating pattern are formed of a material whose visible light reflectance at the interface between them is smaller than a predetermined value, the alignment mark has a convex shape. X that constitutes the section
It becomes difficult for visible light to be reflected between the line transparent film and the visible light transparent grid pattern.

According to the structure of claim 10, after forming a visible-light-reflective grating pattern in the form of a plane lattice on the surface of the X-ray-transmissive film, the visible-light-reflective grating pattern is used as a resist mask to etch the X-ray transmissive film. Then, a concave portion is formed in the front surface portion of the X-ray transparent film in which the back surface side portion of the visible light reflective grating pattern is depressed in a plane lattice shape, and accordingly, a flat portion between the concave portion is formed. Since it becomes a convex portion, an alignment mark having an uneven cross-section is formed.

According to the eleventh aspect, after the visible light reflective grating pattern in the form of a plane lattice is formed on the surface of the X-ray transmissive film, the visible light reflective grating pattern of the X-ray transmissive film is not formed. When a planar grid-like visible light-transmitting film is formed on the surface, the visible light-transmitting film and the X-ray transmitting film form convex portions of the alignment mark, and the back-side portion of the visible-light-reflecting grating pattern in the X-ray transmitting film is formed. The concave portion of the alignment mark is formed.

According to the twelfth aspect, after the surface of the mask support is etched to form a lattice pattern having a concave cross section, an X-ray transparent film is formed on the surface of the mask support to a substantially uniform thickness. After that, when at least the back side portion of the mask support on which the alignment mark is formed is removed, a flat grid-like convex portion formed of an X-ray transparent film and having the same thickness as each other and protruding toward the front surface side and the convex portion are formed. Since the concave portions that are recessed in the shape of a plane lattice are formed between the portions on the back surface side, the alignment mark having an uneven cross section is formed.

According to the structure of the thirteenth aspect, after the visible light transmitting film is formed on the surface of the X-ray transmitting film, the visible light transmitting film is subjected to an etching treatment to form a visible light transmitting grating pattern in a plane lattice shape. When formed, the convex portion of the alignment mark is formed by the back side portion of the visible light transparent pattern in the X-ray transparent film and the visible light transparent lattice pattern, and the visible light transparent pattern is formed in the X-ray transparent film. The concave portion of the alignment mark is formed by the non-existing portion.

According to the structure of claim 14, after forming the visible light transmitting grating pattern on the surface of the mask support, an X-ray transmitting film is formed on the surface of the mask support, and the visible light transmitting characteristic of the X-ray transmitting film is formed. When the lattice-shaped protrusions are formed on the front side of the child pattern and then the back side portion of the mask support is removed,
A convex portion of the alignment mark is formed by the lattice-shaped protruding portion of the X-ray transmitting film and the visible light transmitting lattice pattern, and a concave portion of the alignment mark is formed by the flat portion of the X-ray transmitting film where the lattice-like protruding portion is not formed. Parts are formed.

[0044]

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

FIG. 1 shows a sectional structure of an X-ray mask A according to the first embodiment of the present invention. In the figure, 1 is Si
The support 2 made of a substrate is an X-ray transparent film made of a SiN film formed on the surface of the support 1, and 3 is an LSI pattern made of a W film formed on the surface of the X-ray transparent film 2. still,
The backside of the support 1 in the exposed area is removed by etching in order to transmit X-rays.

Further, in the figure, reference numeral 4 denotes an alignment mark formed on the surface of the X-ray transparent film 2, and the alignment mark 4 has a lattice-like planar shape formed on the surface of the X-ray transparent film 2. 4a and a portion other than the convex portions 4a on the surface of the X-ray transmissive film 2, that is, concave portions 4b having a planar lattice shape formed between the convex portions 4a. Then, a visible light reflective grating pattern 5 made of a W film which is both a visible light reflection film and an X-ray absorber is formed on the surface of the convex portion 4a of the alignment mark 4, and the concave portion 4b of the alignment mark 4 and On the surface of the visible light reflective grating pattern 5, a metal film 7 made of a W film as a visible light reflective film is formed. In the first embodiment, the metal film 7 is formed on the surface of the visible light reflective grating pattern 5 due to the manufacturing technique of the X-ray mask A. It may be formed only on the surface of the concave portion 4b.

Hereinafter, based on FIG. 2, the above X-ray mask A and the semiconductor substrate 30 having the surface coated with a resist 32 will be described.
A method of detecting the positional deviation between the and will be described. The figure shows a partial cross-sectional structure when the X-ray mask A and the semiconductor substrate 30 are aligned. In the figure, 13 is a laser beam irradiated on the alignment mark 4 of the X-ray mask A, and 14 is an alignment mark. 4 is the first-order reflected diffracted light generated by the laser light 13 applied to the laser beam 4.

As shown in the figure, the semiconductor substrate 30 is arranged on the surface side of the X-ray mask A (the upper side of FIG. 1, the right side of FIG. 2) at an appropriate distance. When the alignment mark 4 of the X-ray mask A is irradiated with the laser beam 13 from the back surface side of the X-ray mask A when aligning the X-ray mask A, the W film forming the lattice pattern 5 and the metal film 7 is formed. Since the laser beam 13 is not transmitted, the alignment mark 4
The transmitted diffracted light that reaches the semiconductor substrate 30 through the light is not generated. Therefore, the 0th-order transmitted diffracted light 16 and the 1st-order transmitted diffracted light 1 as described in the section of the related art based on FIG.
Since 8th and higher order transmitted diffracted light does not occur, these 0th order, 1st order
There is no detection error due to the second or higher order transmitted diffracted light.

When the alignment mark 4 is irradiated with the laser light 13 from the back surface side of the X-ray mask A as described above, the laser light 13 is reflected by the visible light reflective grating pattern 5 and the W film forming the metal film 7. Then, the first-order reflected diffracted light 14 is generated. The intensity of the first-order reflected diffracted light 14 periodically changes depending on the size of the step between the convex portion 4a and the concave portion 4b of the alignment mark 4 formed on the X-ray transmissive film 2 that constitutes the diffraction grating. It is known that the intensity of the first-order reflected diffracted light 14 can be maximized by adjusting the etching depth of the concave portion 4b of the alignment mark 4.

Further, since the laser light 13 is reflected by the W film formed on both surfaces of the convex portion 4a and the concave portion 4b of the alignment mark 4, the laser light 13 is reflected by the convex portion 4a and the concave portion 4b. The intensity of the first-order reflected diffracted light 14 is higher than that when it is reflected by the W film formed on only one of the surfaces. For example, the X-ray transmissive film 2 is formed of a SiN film having a refractive index of 2.5, and the laser beam (He-Ne) 13 having a wavelength of 0.633 μm passes through the X-ray transmissive film 2 and a diffraction grating having a pitch of 4 μm. Angle of incidence at 9
When the alignment mark 4 has a step difference of about 0.06 μm or 0.19 μm, the light intensity of the first-order reflected diffracted light 14 is maximized.

Hereinafter, a method of manufacturing the X-ray mask A according to the first embodiment will be described with reference to FIGS.

First, as shown in FIG. 3, as in the conventional X-ray mask manufacturing method, for example, a film having a thickness of 2 is formed on the surface of the support 1 made of a Si substrate whose back surface is not etched.
The X-ray transparent film 2 made of a SiN film of μm is formed. After that, a W film having a thickness of 0.7 μm is formed on the surface of the X-ray transparent film 2, and then the W film is etched by an electron beam exposure method and a reactive dry etching method. An LSI pattern 3 made of a W film and a visible light reflective grating pattern 5 are formed on the surface of 2.

Next, as shown in FIG. 4, a resist mask 8 having an opening 8a for forming the alignment mark 4 is formed on the surface of the X-ray transparent film 2 by photolithography, and then reactive dry etching is performed. The X-ray transparent film 2 is etched by a predetermined thickness. If you do this, X
Since the visible light reflective grating pattern 5 of the W film is already formed on the surface of the line-transmissive film 2 and the opening portion 8a is provided in the resist mask 8, the resist mask 8 is provided in a region facing the opening portion 8a. In addition, since the portion where the visible light reflective grating pattern 5 is not formed is etched, the alignment mark 4 including the above-described convex portion 4a and concave portion 4b is formed on the surface of the X-ray transmissive film 2.

When etching the X-ray transparent film 2 using the lattice pattern 5 as a mask, the resist mask 8 is used.
The region in which the LSI pattern 3 is formed in the X-ray transmissive film 2 may be simultaneously etched without forming.

Next, as shown in FIG. 5, the surface of the alignment mark 4 has a thickness of, for example, 0.
A metal film 7 made of a 2 μm W film and having an uneven cross section is formed. As a method of forming the uneven metal film 7, a W film is formed by sputtering on the surface of the X-ray transparent film 2 while leaving the resist mask 8 when the X-ray transparent film 2 was etched in the previous step. Then, the lift-off method of removing the W film on the surface of the resist mask 8 together with the resist mask 8 can be used.

The method of forming the metal film 7 is not limited to the lift-off method described above, but after the metal film 7 is formed over the entire surface of the semiconductor substrate 1, the surface of the alignment film 4 is formed by photo-etching and etching. A method of leaving the metal film 7 may be adopted. In particular, when a material having a higher etching rate than that of the X-ray absorber forming the visible light reflective grating pattern 5 is used as the metal film 7, the photo-etching method and the etching method can be easily adopted.

Next, as shown in FIG. 6, similarly to the conventional method, the exposed region on the back surface of the support 1 for transmitting X-rays is etched to form the support 1 in a frame shape.

By doing so, the X-ray transparent film 2
An alignment mark 4 composed of a convex portion 4a and a concave portion 4b is formed on the surface of, and a visible light reflective grating pattern 5 made of a W film is formed on the surface of the convex portion 4a of the alignment mark 4, The X-ray mask A in which the metal film 7 made of the W film is formed on the surface of the light-reflective grating pattern 5 and the surface of the concave portion 4a of the alignment mark 4 can be easily and reliably manufactured.

FIG. 7 shows a sectional structure of an X-ray mask B according to the second embodiment of the present invention.

Also in the second embodiment, as in the first embodiment, the X-ray transparent film 2 made of SiN film is formed on the surface of the support 1 made of Si substrate. Unlike the first embodiment, the surface of the X-ray transmissive film 2 is flat, and the surface of the X-ray transmissive film 2 is a plane including the LSI pattern 3 made of a W film and the W film as a first visible light reflection film. The grid-like visible light reflective grid patterns 5 are formed respectively.

The entire surface of the X-ray transparent film 2, the LSI pattern 3 and the visible light reflective grating pattern 5 is covered with SiO 2.
_A visible light transmitting film 9A composed of _two films is formed, whereby the surface of the X-ray transmitting film 2 has a convex portion 4a made of the X-ray transmitting film 2 and the visible light transmitting film 9A and protruding toward the surface side.
And a concave portion 4b formed of a flat surface portion of the X-ray transparent film 2.
The alignment mark 4 is formed by and. In addition, the entire surface of the alignment mark 4 has a second
The metal film 7 made of a W film as the visible light reflection film is formed. The backside of the support 1 in the exposed area is etched so as to transmit X-rays.

The method of detecting the positional deviation between the X-ray mask B and the semiconductor substrate according to the second embodiment is the same as that of the X-ray mask A according to the first embodiment, and the alignment mark of the X-ray mask B is used. 4 is irradiated with laser light from the back surface side, the visible light reflective grating pattern 5 and the W film forming the metal film 7 do not transmit the laser light, and thus the alignment mark 4 is transmitted to reach the semiconductor substrate 30. No diffracted light is generated, and no detection error occurs due to 0th-order, 1st-order, or higher-order transmitted diffracted light.

The method of manufacturing the X-ray mask B according to the second embodiment will be described below with reference to FIGS.

First, the X-ray mask B according to the first embodiment.
In the same manner as in the manufacturing method described above, after the X-ray transparent film 2 made of the SiN film is formed on the surface of the support 1 made of the Si substrate whose back surface is not subjected to the etching treatment, W is formed on the surface of the X-ray transparent film 2. An LSI pattern 3 made of a film and a visible light reflective grating pattern 5 made of a W film as a first visible light reflection film are formed respectively.

Next, as shown in FIG. 8, the X-ray transparent film 2,
A visible light transmitting film 9A made of a SiO ₂ film having a film thickness of 0.1 μm is formed over the entire surfaces of the LSI pattern 3 and the visible light reflecting grating pattern 5. As a result, between the visible light reflective grating patterns 5, the visible light transmissive film 9A is laminated on the X-ray transmissive film 2 to form the convex portion 4a of the alignment mark 4, and the visible light reflective grating is formed. The X-ray transparent film 2 on the back surface side of the pattern 5 constitutes the concave portion 4b of the alignment mark 4.

Next, as shown in FIG. 9, a metal film 7 having a concave-convex cross section as a second visible light reflecting film made of a W film having a thickness of 0.2 μm, for example, is formed on the surface of the alignment mark 4. .. As a method of forming the metal film 7, a W film may be formed over the entire surface of the semiconductor substrate 1 and then only the W film on the surface of the alignment mark 4 may be left by a photo-etching method. The W film may be selectively formed using a resist mask having an opening at a portion corresponding to 4.

Then, as shown in FIG. 10, as in the conventional method, the exposed region on the back surface of the support 1 for transmitting X-rays is removed by etching.

By doing so, the X-ray transparent film 2
An alignment mark 4 composed of a convex portion 4a and a concave portion 4b is formed on the surface of the alignment mark 4, and a metal film 7 as a second visible light reflecting film is formed on the surface of the convex portion 4a of the alignment mark 4, The visible light reflective grating pattern 5 made of the first visible light reflective film on the surface of the concave portion 4a of FIG.
The X-ray mask B on which the ridges are formed can be manufactured easily and reliably.

FIG. 11 shows a sectional structure of an X-ray mask C according to the third embodiment of the present invention. Also in the third embodiment, as in the first embodiment, the LS made of a W film is formed on the surface of the support 1 made of a Si substrate, as in the first and second embodiments.
I pattern 3 is formed.

As a feature of the third embodiment, the alignment mark 4 has concave portions 4b in the form of a plane lattice formed by etching on the surface of the X-ray transparent film 2 and the concave portions 4b on the flat surface. Thus, the metal film 7 made of a W film as a visible light reflecting film is formed over the entire surface of the alignment mark 4 on the surface of the alignment mark 4. There is. In the third embodiment, due to the manufacturing technology and the strength,
Concave portion 4 of alignment mark 4 in X-ray transparent film 2
The back surface of b is projected to the back surface side.

FIG. 12 illustrates a method for detecting the positional deviation between the X-ray mask C and the semiconductor substrate 30 according to the third embodiment. The positional deviation between the X-ray mask C and the semiconductor substrate 30 is detected. The method is the same as that of the X-ray mask A according to the first embodiment described above, and the alignment mark 4 of the X-ray mask C is irradiated with the laser beam 13 from the back surface side. In this case, since the W film forming the metal film 7 does not transmit the laser light 13, the transmitted diffracted light that passes through the alignment mark 4 and reaches the semiconductor substrate 30 is not generated, and the 0th order, the 1st order or the high order. There is no detection error due to the next transmitted diffracted light.

The intensity of the first-order reflected diffracted light 14 obtained by the laser light 13 being reflected by the metal film 7 formed on the surface of the alignment mark 4 is the same as that of the convex portion 4a of the alignment mark 4 and the concave portion. It is known that the level difference with the portion 4b changes periodically. Therefore, the intensity of the first-order reflected diffracted light 14 can be maximized by adjusting the depth of the concave portion 4b of the alignment mark 4. For example, laser light having a wavelength of 0.633 μm (He-
When the Ne) 13 is applied to the alignment mark 4 made of a diffraction grating having a pitch of 4 μm at an incident angle of 9 degrees, X is obtained when the step of the diffraction grating (diffraction pattern) is about 0.16 μm or 0.32 μm. The light intensity of the first-order reflected diffracted light 14 reflected in the direction perpendicular to the line mask C is maximized.

Hereinafter, based on FIG. 13 to FIG.
A method of manufacturing the X-ray mask C according to the example will be described.

First, as shown in FIG. 13, a conventionally known photo-etching process is applied to a portion of the front surface of the support 1 made of a Si substrate, the back surface of which is not etched, where the alignment mark 4 is to be formed. Method is used to selectively etch a predetermined depth to obtain, for example, a depth of 0.3.
By forming 40 concave linear patterns 10 a having a width of 2 μm and a length of 150 μm at intervals of 2 μm, the lattice pattern 10 having a pitch of 4 μm is formed on the surface of the support 1.
To form.

Next, as shown in FIG. 14, the X-ray transparent film 2 made of a SiN film is formed on the entire surface of the support 1. By doing so, the alignment mark 4 including the convex portions 4a and the concave portions 4b is formed on the X-ray transmissive film 2 following the concave-convex shape of the lattice pattern 10.

Next, the entire surface of the X-ray transmission film 2 is an X-ray absorber and a visible light reflection film, and has a thickness of 0.7 μm.
After forming a W film of m, by performing an electron beam exposure method and a reactive dry etching method on the W film,
As shown in FIG. 15, the LSI pattern 3 made of a W film is formed on the surface of the X-ray transparent film 2, and the metal film 7 made of a W film is formed on the surface of the alignment mark 4 of the X-ray transparent film 2.

Next, as shown in FIG. 16, similarly to the conventional method, the exposed region on the back surface of the support 1 for transmitting X-rays is etched to form the support 1 in a frame shape.

By doing so, the X-ray transparent film 2
A simple and reliable production of an X-ray mask C in which an alignment mark 4 composed of a convex portion 4a and a concave portion 4b is formed on the surface of, and a metal film 7 made of a W film is formed on the surface of the alignment mark 4 You can

In the method of manufacturing the X-ray mask C according to the third embodiment, after the X-ray transparent film 2 made of the SiN film is formed, the LSI pattern 3 made of the W film and the metal film 7 are formed. After that, the exposed region of the support 1 was etched, but instead of this, the X-ray transmission film 2 made of a SiN film was used.
After forming the, the exposed area of the support 1 is etched,
After that, the LSI pattern 3 made of a W film and the metal film 7 may be formed.

FIG. 17 shows the sectional structure of an X-ray mask D according to the fourth embodiment of the present invention and the alignment of the X-ray mask D and the semiconductor substrate 30.

In the X-ray mask D according to the fourth embodiment, the surface of the X-ray transmission film 2 having a film thickness of 2 μm, which is made of a SiN film formed on the surface of a support (not shown) and is also a visible light transmission film. A visible light transmissive grating pattern 11 made of a visible light transmissive film, which is a SiO ₂ film having a film thickness of 0.1 μm, is formed on the surface. As a result, the alignment mark 4 having a planar lattice-shaped and uneven cross-section is formed by the convex portion 4a including the X-ray transparent film 2 and the visible light transparent grating pattern 11 and the concave portion 4b including only the X-ray transparent film 2. Has been done. The thickness of the alignment mark 4 is 0.8 μm on the surface.
The metal film 7 is formed as a visible light reflecting film made of the W film. An LSI pattern 3 made of a W film is formed on the surface of the X-ray transparent film 2.

When the positional deviation between the X-ray mask D and the semiconductor substrate 30 according to the fourth embodiment is detected, the laser beam 13 is radiated from the rear surface to the alignment mark 4 of the X-ray mask D. The first-order reflected diffracted light 14 can be obtained, and since the W film forming the metal film 7 does not transmit the laser light, the transmitted diffracted light that passes through the alignment mark 4 and reaches the semiconductor substrate 30 does not occur, There is no detection error due to the first-order, first-order, or higher-order transmitted diffracted light.

Hereinafter, based on FIGS. 18 to 22, the fourth
A method of manufacturing the X-ray mask D according to the example will be described.

First, as shown in FIG. 18, an X-ray transparent film 2 made of a SiN film is formed on the surface of a support 1 made of a Si substrate, and then, as shown in FIG. A visible light transmitting film 9B made of a SiO ₂ film having a film thickness of 0.1 μm is formed on the surface. Then, the visible light transmitting film 9B is subjected to a photo-etching method to form a visible light transmitting grating pattern 11 made of the visible light transmitting film 9B as shown in FIG. Thereby, on the surface of the support 1, the convex portion 4a including the X-ray transparent film 2 and the visible light transparent grid pattern 11,
An alignment mark 4 having a planar grid-like and a concave-convex cross-section is formed by the concave portion 4b formed only of the X-ray transparent film 2.

Next, as shown in FIG. 21, the X-ray transparent film 2
Further, after forming a metal film 7 which is a visible light reflecting film made of a W film having a film thickness of 0.8 μm and is also an X-ray absorber over the entire surface of the alignment mark 4, the metal film 7 is photographed. By performing the etching method, as shown in FIG. 22, the metal film 7 on the surface of the alignment mark 4 is left. In the present embodiment, the LSI pattern 3 is simultaneously formed together with the metal film 7 on the surface of the alignment mark 4 by the step of subjecting the metal film 7 to the photo-etching method. After that, as shown in FIG. 23, the exposed region on the back surface of the support 1 where X-rays are transmitted is etched to form the support 1 in a frame shape.

FIG. 24 shows the sectional structure of an X-ray mask E according to the fifth embodiment of the present invention and the alignment of the X-ray mask E and the semiconductor substrate 30.

In the X-ray mask E according to the fifth embodiment, the surface of the X-ray transmission film 2 having a thickness of 2 μm, which is a visible light transmission film and is made of a SiN film formed on the surface of a support (not shown). Is formed with projections formed by projecting the X-ray transmissive film 2 in a planar lattice shape, and on the back surface of the X-ray transmissive film 2 on the back side of the projections, a planar SiO corresponding to the projections is formed. _A visible light transmitting grid pattern 11 composed of _two films is formed. As a result, on the surface of the support 1, X
Visible light transmitting grating pattern 11
The alignment mark 4 of the grid-like plane is formed by the convex portion 4a made of and the concave portion 4b made of only the X-ray transmissive film 2. That is, the X-ray mask E according to the fifth embodiment and the X-ray mask D according to the fourth embodiment are in a state where the laminated structure of the visible light transmissive grating pattern is reversed in the front-back direction. Also in the X-ray mask E, the metal film 7 as a visible light reflecting film made of a W film having a film thickness of 0.8 μm is formed on the surface of the alignment mark 4, and the surface of the X-ray transmitting film 2 is formed. Has an LSI pattern 3 formed of a W film.

When the misalignment between the X-ray mask E and the semiconductor substrate 30 according to the fifth embodiment is detected, the alignment mark 4 of the X-ray mask E is irradiated with the laser beam 13 from the back side. The first-order reflected diffracted light 14 can be obtained, and the W film forming the metal film 7 is the laser light 13
Is not transmitted, no transmitted diffracted light that passes through the alignment mark 4 and reaches the semiconductor substrate 30 is generated.
A detection error due to the second or higher order transmitted diffracted light does not occur.

Hereinafter, based on FIGS.
A method of manufacturing the X-ray mask E according to the example will be described.

First, as shown in FIG. 25, a visible light transmitting film 9C made of a SiO ₂ film having a film thickness of 0.1 μm is formed on the surface of a support 1 made of a Si substrate, and then the visible light transmitting film 9 is formed.
By subjecting C to a photo-etching method, as shown in FIG. 26, a visible light transmitting grating pattern 11 made of a visible light transmitting film 9C is formed on the surface of the support 1. Then, as shown in FIG. 27, the X-ray transmission film 2 having an uneven cross section made of a SiN film over the entire surface of the support 1 and the visible light transmission film 9C.
To form.

Next, as shown in FIG. 28, the X-ray transparent film 2
X consisting of 0.8 μm thick W film over the entire surface of
After forming the metal film 7 which is a line absorber and is also a visible light reflecting film, the metal film 7 is subjected to a photo-etching method to obtain a visible light transmitting grating pattern 1 as shown in FIG.
The metal film 7 on the surface of 1 is left. In this example,
An LSI is formed together with the metal film 7 on the surface of the visible light transmitting grating pattern 11 by a process of subjecting the metal film 7 to photolithography.
Pattern 3 is also formed at the same time.

Next, as shown in FIG. 30, the exposed area on the back surface of the support 1 for transmitting X-rays is etched to form the support 1 in the shape of a frame. An alignment mark 4 of a grid-like plane is formed, which includes a convex portion 4a made of the visible light transmitting grating pattern 11 and a concave portion 4b made of only the X-ray transmitting film 2. The step of the diffraction grating of the alignment mark 4 is S
Since it is determined by the film thickness of the visible light transmitting film 9C (see FIG. 25) made of the iO ₂ film, by setting the film thickness of the visible light transmitting film 9C to a desired value, the step of the diffraction grating can be set to a desired value. The size can be set to obtain the optimum diffraction efficiency.

In each of the above embodiments, the X-ray transparent film 2 is used.
A SiN film is used as
An i film, a SiC film, a diamond thin film, or the like may be used, and as the X-ray absorber configured as the visible light reflective grating pattern 5 of the alignment mark 4 and the metal film 7, Au is used instead of the W film. Other heavy metal thin films such as Ta and Ta may be used.

In FIG. 31, a conventional X-ray mask G is used.
FIG. 6 is a diagram showing changes in the alignment signal when the gap between the line mask G and the semiconductor substrate 30 is changed, the horizontal axis indicates the gap between the X-ray mask and the semiconductor substrate, and the vertical axis indicates the alignment signal. ing. The change in this alignment signal was measured as follows. That is, alignment is performed by setting the gap between the X-ray mask G and the semiconductor substrate 30 to a predetermined value, and the alignment signal at this time is recorded. Next, without changing the planar relative position between the X-ray mask G and the semiconductor substrate 30, only the gap between the X-ray mask G and the semiconductor substrate 30 is 40 nm.
It was changed in steps, and the alignment signal at that time was recorded.

Since the planar relative position between the X-ray mask G and the semiconductor substrate 30 does not change, the alignment signal changes even if the gap between the X-ray mask G and the semiconductor substrate 30 changes. Although it should not be done, according to the conventional X-ray mask G, a signal change of about ± 40 nm occurs. This value directly affects the alignment as an alignment error.

FIG. 32 is a diagram showing a change in the alignment signal when the X-ray mask B according to the second embodiment of the present invention is used and measurement is performed by the same measurement method as described above.
The gap between the line mask and the semiconductor substrate, the vertical axis represents the alignment signal. As is clear from FIG. 32,
The change of the alignment signal is suppressed to about ± 5 nm, and the effect of the present invention can be confirmed.

[0097]

As described above, according to the X-ray mask of the invention of claim 1, since the visible light reflecting film is formed on each surface of the convex portion and the concave portion of the alignment mark, the alignment mark is irradiated. Since visible light does not reach the semiconductor substrate through the alignment mark,
The first-order reflected diffracted light generated by the alignment mark can be clearly detected without being disturbed by unnecessary reflected light.

In the X-ray mask according to the second aspect of the present invention, the surface of the X-ray permeable film is recessed in the shape of a plane lattice to form the concave portions, so that the convex portions are formed by the flat portions between the concave portions. Therefore, it is possible to easily form an alignment mark having an uneven cross section.

In the X-ray mask according to the invention of claim 3, the visible light reflecting film formed on the surface of the convex portion of the alignment mark is formed of the same X-ray absorber as the LSI pattern.
Since the visible light reflection film can be formed in the same process as the LSI pattern, the accuracy of the relative position between the alignment mark and the LSI pattern can be improved.

According to the X-ray mask of the fourth aspect of the present invention, the visible light reflecting pattern formed of the first visible light reflecting film formed on the surface of the X-ray transmitting film and the surface of the visible light transmitting film are formed. Since the surface of the alignment mark is covered with the second visible light reflecting film, the visible light applied to the alignment mark does not pass through the alignment mark and reach the semiconductor substrate. Similar to the line mask, the first-order reflected diffracted light generated by the alignment mark can be clearly detected without being disturbed by unnecessary reflected light.

The X-ray mask according to the invention of claim 5 is the first
Since the visible light reflecting film is formed of the same X-ray absorber as the LSI pattern, the visible light reflecting grating pattern can be formed in the same step as the LSI pattern, and therefore the accuracy of the relative position between the alignment mark and the LSI pattern is improved. You can

According to the X-ray mask of the sixth aspect of the present invention, the alignment mark includes a convex portion formed of an X-ray transmissive film and protruding toward the front surface, and a concave portion recessed toward the back surface between the convex portions. Since the visible light reflecting film is formed on each surface of the convex portion and the concave portion of the alignment mark, visible light irradiated on the alignment mark does not pass through the alignment mark and reach the semiconductor substrate. Similarly to the X-ray mask of claim 1, the first-order reflected diffracted light generated by the alignment mark can be clearly detected without being disturbed by unnecessary reflected light.

According to the X-ray mask of the seventh and eighth aspects of the present invention, since the visible light reflection film is formed on the surface of the alignment mark, like the X-ray mask of the first aspect, it is not disturbed by unnecessary reflected light. The first-order reflected diffracted light generated by the alignment mark can be clearly detected.

According to the X-ray mask of the ninth aspect of the present invention, the X-ray transmission film and the visible light transmitting grating pattern are formed of a material such that the visible light reflectance at their interface becomes smaller than a predetermined value. Since it becomes difficult for visible light to be reflected between the X-ray transmitting film of the alignment mark and the visible light transmitting grating pattern, the first-order reflected diffracted light can be reliably detected.

Therefore, according to the X-ray mask of the present invention, the first-order reflected diffracted light generated by the alignment mark can be clearly detected without being disturbed by the unnecessary reflected diffracted light, so that the accuracy is high. The positional deviation can be detected, and almost all of the visible light with which the alignment mark is irradiated can be detected as the alignment signal light, so that the intensity of the alignment signal light is increased and the signal S / N is improved.

According to the method of manufacturing an X-ray mask of the tenth aspect of the present invention, after the visible light reflective grating pattern is formed on the surface of the X-ray transparent film, the visible light reflective grating pattern is used as a resist mask for the X-ray. When the transmissive film is subjected to etching treatment, concave portions are formed on the surface of the X-ray transmissive film, in which the back side portion of the visible light reflective grating pattern is depressed in a planar lattice shape,
Along with this, the flat portion between the concave portions becomes a convex portion, so that the X-ray mask according to claim 1 can be easily and reliably manufactured.

According to the method for manufacturing an X-ray mask of the eleventh aspect of the present invention, after the visible light reflective grating pattern is formed on the surface of the X-ray transmissive film, the visible light reflective grating pattern is formed in the X-ray transmissive film. When the visible light transmitting film is formed on the surface of the unexposed portion, the convex portion of the alignment mark is formed by the visible light transmitting film and the X-ray transmitting film, and the back side portion of the visible light reflecting grating pattern in the X-ray transmitting film is formed. Since the concave part of the alignment mark is formed by
The X-ray mask of claim 4 can be manufactured easily and reliably.

According to the method of manufacturing an X-ray mask of the twelfth aspect of the present invention, after forming a lattice pattern having a concave cross section on the surface of the mask support, an X-ray transparent film is formed on the surface of the mask support with a substantially uniform thickness. When the back side portion of the mask support is removed, the convex portions of the flat lattice-like shape which are made of an X-ray transparent film and have the same thickness and project toward the front surface are formed between the convex portions. Since the concave portions that are recessed in the shape of a plane lattice are formed on the back surface side, the X-ray mask of claim 6 can be manufactured easily and reliably.

According to the X-ray mask manufacturing method of the thirteenth aspect of the present invention, after the visible light transmitting film is formed on the surface of the X-ray transmitting film, the visible light transmitting film is subjected to etching treatment to form a planar grating. When a visible light-transmissive grating pattern is formed, a convex portion of the alignment mark is formed by the back side of the visible light-transmissive pattern in the X-ray transmissive film and the visible light transmissive grating pattern, and the visible light in the X-ray transmissive film is formed. Since the concave portion of the alignment mark is formed by the portion where the light transmissive pattern is not formed, the X-ray mask according to the invention of claim 7 can be manufactured easily and reliably.

According to the X-ray mask manufacturing method of the fourteenth aspect of the present invention, after the visible light transmitting grating pattern is formed on the surface of the mask support, the X-ray transmitting film is formed on the surface of the mask support. When the grid-like protrusions are formed on the front side of the visible light transmitting grating pattern in the X-ray transmitting film and then the back side portion of the mask support is removed, the grid-like protruding portions of the X-ray transmitting film and the visible light transmitting grating pattern are formed. The concave portion of the alignment mark is formed by the flat portion of the X-ray transparent film on which the convex portion of the alignment mark is not formed and the lattice-like protruding portion of the X-ray transparent film is not formed. Can be manufactured easily and reliably.

[Brief description of drawings]

FIG. 1 is a sectional view of an X-ray mask according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an alignment state between an X-ray mask and a semiconductor substrate according to the first embodiment.

FIG. 3 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the first example.

FIG. 4 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the first example.

FIG. 5 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the first example.

FIG. 6 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the first example.

FIG. 7 is a sectional view of an X-ray mask according to a second embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the second embodiment.

FIG. 9 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the second embodiment.

FIG. 10 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the second embodiment.

FIG. 11 is a sectional view of an X-ray mask according to a third embodiment of the present invention.

FIG. 12 is a sectional view showing a state of alignment between an X-ray mask and a semiconductor substrate according to the third embodiment.

FIG. 13 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the third embodiment.

FIG. 14 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the third embodiment.

FIG. 15 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the third embodiment.

FIG. 16 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the third embodiment.

FIG. 17 is a sectional view showing a state of alignment between the X-ray mask and the semiconductor substrate according to the fourth example.

FIG. 18 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the fourth example.

FIG. 19 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the fourth embodiment.

FIG. 20 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the fourth embodiment.

FIG. 21 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the fourth embodiment.

FIG. 22 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the fourth example.

FIG. 23 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the fourth example.

FIG. 24 is a cross-sectional view showing the alignment state of the X-ray mask and the semiconductor substrate according to the fifth example.

FIG. 25 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the fifth embodiment.

FIG. 26 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the fifth embodiment.

FIG. 27 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the fifth embodiment.

FIG. 28 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the fifth embodiment.

FIG. 29 is a cross-sectional view showing a step in the method of manufacturing the X-ray mask according to the fifth embodiment.

FIG. 30 is a sectional view showing a step in the method of manufacturing the X-ray mask according to the fifth embodiment.

FIG. 31 is a diagram showing an alignment signal error when a conventional X-ray mask is used.

FIG. 32 is a diagram showing an alignment signal error when the X-ray mask according to the second embodiment of the present invention is used.

FIG. 33 is a sectional view of a conventional X-ray mask.

FIG. 34 is a sectional view showing a state of alignment between a conventional X-ray mask and a semiconductor substrate.

[Explanation of symbols]

 A, B, C, D, E, G X-ray mask 1 Support 2 X-ray transparent film 3 LSI pattern 4 Alignment mark (X-ray mask) 4a Convex part 4b Concave part 5 Visible light reflective grating pattern (first Visible light reflection film) 7 metal film (visible light reflection film, second visible light reflection film) 8 resist mask 8a openings 9A, 9B, 9C visible light transmission film 10 lattice pattern 10a concave linear pattern 11 visible light transmission characteristics Child pattern 13, 13A, 13B Laser light 14 First-order reflected diffracted light 15 Other first-order reflected diffracted light 16 0th-order transmitted diffracted light 17 Unnecessary diffracted light 30 Semiconductor substrate 31 Alignment mark (semiconductor substrate) 32 Resist

Claims (14)

[Claims] 1. An X-ray mask comprising an X-ray transparent film formed on the surface of a mask support and an alignment mark formed on the surface of the X-ray transparent film, wherein the alignment mark is the X-ray transparent film. The surface portion of the film is composed of a convex portion and a concave portion which are alternately formed in a planar lattice-like cross-sectional uneven shape, and a visible light reflecting film is formed on each surface of the convex portion and the concave portion of the alignment mark. An X-ray mask characterized by being formed respectively. 2. The concave portion of the alignment mark is formed by denting the surface portion of the X-ray transparent film in a plane lattice shape, and the convex portion of the alignment mark is formed on the surface portion of the X-ray transparent film. The X-ray mask according to claim 1, wherein the X-ray mask comprises a flat portion between the concave portions. 3. The X-ray mask according to claim 1, wherein the visible light reflection film formed on the surface of the convex portion of the alignment mark is an X-ray absorber. 4. An X-ray mask comprising an X-ray transmissive film formed on the surface of a mask support and an alignment mark formed on the surface of the X-ray transmissive film. Is a plane-lattice-like visible light-reflecting grating pattern formed of a first visible-light-reflecting film, and a plane lattice-like pattern is formed on the surface of the X-ray transmitting film where the visible-light-reflecting grating pattern is not formed. A visible light transmitting film is formed, and a second visible light reflecting film is formed on the surface of the visible light transmitting film. The alignment mark has a convex shape composed of the X-ray transmitting film and the visible light transmitting film. An X-ray mask comprising: a concave portion formed of a portion and a back side portion of the visible light reflective grating pattern in the X-ray transparent film. 5. The X-ray mask according to claim 4, wherein the first visible light reflecting film is an X-ray absorber. 6. An X-ray mask comprising an X-ray transparent film formed on the surface of a mask support and an alignment mark formed on the surface of the X-ray transparent film, wherein the alignment mark is the X-ray. It is composed of a flat lattice-shaped convex portion that is made of a permeable film and has the same thickness as each other and projects toward the front surface side, and a concave portion that is recessed in a flat lattice shape toward the back surface between the convex portions, An X-ray mask, wherein visible light reflecting films are formed on the surfaces of the convex portion and the concave portion of the alignment mark, respectively. 7. An X-ray mask comprising an X-ray transparent film formed on the surface of a mask support and an alignment mark formed on the surface of the X-ray transparent film, wherein the surface of the X-ray transparent film is formed. A visible-light-transmissive grating pattern in the form of a plane lattice made of a visible-light-transmissive film is formed, and the alignment mark is composed of the back side of the visible-light-transmissive pattern in the X-ray transmissive film and the visible-light-transmissive grating pattern. It is composed of a convex portion and a concave portion which is a flat portion of the X-ray transmissive film on which the visible light transmissive pattern is not formed, and a visible light reflective film is formed on the surface of the alignment mark. An X-ray mask characterized by the above. 8. An X-ray mask comprising an X-ray transparent film formed on the surface of a mask support and an alignment mark formed on the surface of the X-ray transparent film, wherein a back surface of the X-ray transparent film is provided. A visible-light-transmissive grating pattern in the form of a planar lattice is formed from the visible-light-transmissive film so that the back surfaces are flush with each other, and the visible-light-transmissive grating pattern on the front side of the X-ray transmissive film is on the front side. The lattice-like protrusions in the form of a plane lattice formed by the X-ray transparent film protruding to the front side are formed,
The alignment mark has a concave shape including a convex portion formed of the lattice-like protruding portion of the X-ray transparent film and the visible light transmitting lattice pattern and a flat portion formed of the X-ray transparent film on which the lattice-like protruding portion is not formed. And a visible light reflecting film is formed on the surface of the alignment mark. 9. The X-ray transmissive film and the visible light transmissive grating pattern are made of a material such that the reflectance of visible light at the interface between the X-ray transmissive film and the visible light transmissive grating pattern is smaller than a predetermined value. The X-ray mask according to claim 7, wherein the X-ray mask is formed by the following methods. 10. A step of forming an X-ray transparent film on the surface of a mask support, and a step of forming a visible light reflective grating pattern in the form of a plane grating made of a visible light reflective film on the surface of the X-ray transparent film. By performing an etching process on the X-ray transmissive film using the visible light reflective grating pattern as a resist mask, the back surface of the visible light reflective grating pattern on the surface of the X-ray transmissive film is removed. A step of forming an alignment mark composed of concave portions which are recessed in a plane lattice and convex portions which are flat portions between the concave portions, and a visible light reflecting film is formed on the surface of the alignment marks. A method for manufacturing an X-ray mask, comprising: 11. A step of forming an X-ray transmissive film on the surface of a mask support, and forming a visible light-reflective grating pattern in the form of a plane lattice, which is a first visible light reflective film, on the surface of the X-ray transmissive film. And the step of forming a visible light transparent film in the form of a plane lattice on the surface of the X-ray transparent film where the visible light reflective grating pattern is not formed, A step of forming an alignment mark composed of a convex portion formed of and a concave portion formed of the back side portion of the visible light reflective grating pattern in the X-ray transmissive film, and a second step on the surface of the visible light transmissive film. And a step of forming a visible light reflection film.
Method of manufacturing line mask. 12. A step of forming a lattice pattern having a plane lattice shape and a concave cross section on the surface of the mask support by etching a portion of the surface of the mask support where an alignment mark is formed, and the mask support. A step of forming an X-ray transmissive film on the surface of the body with a substantially uniform thickness; a step of forming a visible light reflection film on a portion of the surface of the X-ray transmissive film where an alignment mark is to be formed; By removing at least the portion on the back side of the portion where the alignment mark is formed, between the convex portions of the planar X-ray transparent film having the same thickness and projecting toward the front surface, and between the convex portions. And a step of forming an alignment mark composed of concave portions that are recessed toward the back surface side in a plane lattice shape. 13. A step of forming an X-ray transparent film on the surface of a mask support, a step of forming a visible light transparent film on at least a portion of the surface of the X-ray transparent film where an alignment mark is formed, and the visible light. By etching the transparent film to form a visible light transparent grid pattern in the form of a plane grid made of the visible light transparent film, a portion of the X-ray transparent film on the back side of the visible light transparent pattern and A step of forming an alignment mark composed of a convex portion formed of a visible light transparent grid pattern and a concave portion formed of a portion of the X-ray transparent film where the visible light transparent pattern is not formed; and the alignment mark And a step of forming a visible light reflective film on the surface of the X-ray mask. 14. A step of forming a visible light transmitting grating pattern in the form of a plane grating made of a visible light transmitting film on at least a portion of the surface of the mask supporting body where an alignment mark is formed, and an X-ray on the surface of the mask supporting body. Forming a transparent film, thereby forming a grid-like projecting portion in the form of a flat grid in which the X-ray transmissive film is projected to the front side on the front side of the visible light transmissive grating pattern in the X-ray transmissive film; X
A step of forming a visible light reflecting film on a portion of the surface of the X-ray transparent film where an alignment mark is to be formed, and at least a backside portion of the mask support where the alignment mark is to be formed are removed. An alignment mark is formed which is composed of a convex portion formed of the lattice-shaped protruding portion and the visible light transmitting lattice pattern and a concave portion formed of a flat portion of the X-ray transparent film where the lattice-shaped protruding portion is not formed. A method for manufacturing an X-ray mask, comprising: