WO2014034033A1 - Diffraction grating and manufacturing method for diffraction grating, grating unit and x-ray image pick-up unit - Google Patents

Abstract

This diffraction grating, manufacturing method for the diffraction grating, grating unit, and X-ray image pick-up unit are configured so that a diffraction region is formed on a first main side of a substrate, and grooves are formed on a second main side opposing the first main side.

Description

Diffraction grating, diffraction grating manufacturing method, grating unit, and X-ray imaging apparatus

The present invention relates to a bendable diffraction grating in which members having the same shape are periodically arranged, and a method of manufacturing a diffraction grating for manufacturing the diffraction grating. The present invention relates to a grating unit in which a plurality of diffraction gratings are arranged, and an X-ray imaging apparatus using the diffraction grating and the grating unit.

The diffraction grating is used as a spectroscopic element having a one-dimensional periodic structure composed of a large number of parallel members in an optical system of various apparatuses. In recent years, an application to an X-ray imaging apparatus has been attempted. The diffraction gratings are classified into transmission diffraction gratings and reflection diffraction gratings when classified by the diffraction method. Furthermore, the transmission diffraction gratings periodically arrange light absorbing portions on a substrate that transmits light. There are an amplitude type diffraction grating (absorption type diffraction grating) and a phase type diffraction grating in which portions for changing the phase of light are periodically arranged on a substrate that transmits light. Here, absorption means that more than 50% of light is absorbed by the diffraction grating, and transmission means that more than 50% of light passes through the diffraction grating.

Near-infrared, visible light, or ultraviolet diffraction gratings can be manufactured relatively easily because near-infrared, visible light, and ultraviolet light are sufficiently absorbed by a very thin metal. For example, a metal film is deposited on a substrate such as glass to form a metal film on the substrate, and the metal film is patterned into a grating, whereby an amplitude type diffraction grating using a diffraction grating is manufactured. In the amplitude type diffraction grating for visible light, when aluminum (Al) is used as the metal, the transmittance for visible light (about 400 nm to about 800 nm) in aluminum is 0.001% or less. A thickness of about 100 nm is sufficient.

On the other hand, as is well known, X-rays are generally very small in absorption by substances and the phase change is not so large. Even when an absorption diffraction grating for X-rays is manufactured with relatively good gold (Au), the thickness of the gold is several tens of μm or more. As described above, in the diffraction grating for X-rays, when a periodic structure is formed with a transmission portion, an absorption portion, and a phase change portion with a uniform width and a pitch of several μm to several tens of μm, The ratio (aspect ratio = thickness / width) is a high aspect ratio of 5 or more.

In addition, when such an X-ray diffraction grating is used in a predetermined apparatus, a certain size may be required. For example, when an X-ray diffraction grating is used in an X-ray diagnostic apparatus, the size of a certain size, for example, a square having a side of 20 cm or more (□ 20 cm or more) is large due to the diagnostic area to be diagnosed at one time. is necessary. On the other hand, the above-described diffraction grating having a fine structure is often manufactured using a silicon wafer in which a fine processing technique is relatively established. Since this silicon wafer generally has a diameter of 6 inches (φ6 inches), a diffraction grating that can be produced from this φ6 inch silicon wafer is a square (□ about 10 cm) with a side of about 10 cm. It becomes. For this reason, in order to realize the above-described diffraction grating of 20 cm or more, it is necessary to connect a plurality of diffraction gratings of about 10 cm. Therefore, for example, Patent Document 1 discloses a diffraction grating unit in which a plurality of diffraction gratings are arranged along a curved surface. The grating disclosed in Patent Document 1 is composed of a plurality of small gratings arranged along a virtual cylindrical surface with a virtual line passing through the focal point of the radiation source as a central axis.

Incidentally, the diffraction grating has a high aspect ratio as described above, and an X-ray source that emits X-rays is generally a point wave source. For this reason, even when a plurality of small lattices are arranged along a virtual cylindrical surface with a virtual line passing through the focal point of the radiation source as a central axis, such as the lattice (grid unit) disclosed in Patent Document 1, Since each small lattice is a plane, X-rays are incident obliquely in the region of both ends of the small lattice (adjacent portions of the small lattices adjacent to each other), resulting in so-called vignetting. End up. For this reason, noise is included in the result through the lattice, and the accuracy of the result is lowered.

On the other hand, in order to prevent the occurrence of such vignetting, it is conceivable to reduce the size of the small lattice. However, if the size of the small grating is reduced, it is necessary to arrange a larger number of small gratings along the virtual cylindrical surface in order to form a diffraction grating unit of a predetermined size. As a result, alignment between the small lattices is difficult and complicated, and defects are likely to occur at the joints between the small lattices. Thus, if the size of the small lattice is reduced, the merit of manufacturing the maximum size lattice that can be manufactured from one wafer is lost.

JP 2011-206161 A

The present invention has been made in view of the above circumstances, and an object thereof is to provide a diffraction grating and a method of manufacturing a diffraction grating for manufacturing the diffraction grating. The present invention also provides a grating unit in which a plurality of the diffraction gratings are arranged, and an X-ray imaging apparatus using the diffraction grating or the grating unit.

In the diffraction grating, the diffraction grating manufacturing method, the grating unit, and the X-ray imaging apparatus according to the present invention, the grating region is formed on one main surface of the substrate, and the groove is formed on the other main surface facing the one main surface. It is a thing.

The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

It is a perspective view which shows the structure of the grating | lattice in 1st Embodiment. It is sectional drawing for demonstrating the manufacturing process of the grating | lattice in 1st Embodiment. It is a perspective view which shows the structure of the grating | lattice in 2nd Embodiment. It is sectional drawing for demonstrating the manufacturing process of the grating | lattice in 2nd Embodiment. It is a perspective view which shows the structure of the grating | lattice in 3rd Embodiment. It is sectional drawing for demonstrating the manufacturing process of the grating | lattice in 3rd Embodiment. It is sectional drawing for demonstrating the manufacturing process of the grating | lattice in the modification of 3rd Embodiment. It is sectional drawing which shows the structure of the grating | lattice in 4th Embodiment. It is a figure for demonstrating one Example of a grating | lattice. It is a perspective view which shows the structure of the Talbot interferometer for X-rays in 5th Embodiment. It is a top view which shows the structure of the Talbot low interferometer for X-rays in 6th Embodiment. It is explanatory drawing which shows the structure of the X-ray imaging device in 7th Embodiment.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted suitably. Further, in this specification, when referring generically, it is indicated by a reference symbol without a suffix, and when referring to an individual configuration, it is indicated by a reference symbol with a suffix.

(First embodiment)
FIG. 1 is a perspective view showing a configuration of a lattice in the first embodiment. FIG. 2 is a cross-sectional view for explaining the manufacturing process of the grating in the first embodiment.

As shown in FIGS. 1 and 2C, the lattice DGa of this embodiment is opposed to the base 11, the lattice region 12 a formed on one main surface of the base 11, and the one main surface of the base 11. And a groove 13a formed on the other main surface.

The base material 11 is a plate-like member formed from a predetermined material. For example, in this embodiment, since the lattice DGa is used for X-rays, the base material 11 is formed from a predetermined material having a characteristic of transmitting or absorbing X-rays. Thus, the base material 11 may be formed of an appropriate material according to the intended use of the lattice DGa. In this embodiment, since the microfabrication technique is substantially established, the base material 11 is formed of silicon (Si) having a characteristic of transmitting X-rays, and is, for example, a silicon wafer.

The lattice region 12a is a region formed on one main surface of the base material 11 and periodically provided with a plurality of members having the same shape. When the orthogonal coordinate system of DxDyDz is set as shown in FIG. 1, the lattice region 12a has a predetermined thickness (depth) H (Dz direction perpendicular to the lattice surface DxDy (normal direction of the lattice surface DxDy)). A plurality of metal portions 121 having a length and extending linearly in one direction (long direction) Dx, and a plurality of silicon portions having the predetermined thickness H and extending linearly in the one direction Dx 122. That is, the metal portion 121 has a plate shape or a layer shape having a long linear shape extending in the one direction Dx on the lattice surface DxDy, and is a plate shape or a layer shape along the DxDz surface orthogonal to the lattice surface DxDy. It is. The silicon portion 122 has a plate shape or a layer shape having a long linear shape extending in the one direction Dx on the lattice surface DxDy, and is a plate shape or a layer shape along the DxDz plane orthogonal to the lattice surface DxDy.

The plurality of metal portions 121 and the plurality of silicon portions 122 are alternately arranged in the lattice plane DxDy in a direction (width direction) Dy orthogonal to the one direction Dx, and the width direction Dy is a normal line. Arranged parallel to the surface. For this reason, the plurality of metal portions 121 are respectively arranged at predetermined intervals in the width direction Dy orthogonal to the one direction Dx. In other words, the plurality of silicon portions 122 are disposed at predetermined intervals in the width direction Dy perpendicular to the one direction Dx. The predetermined interval (pitch) P is constant in this embodiment. That is, the plurality of metal portions 121 (the plurality of silicon portions 122) are respectively arranged at equal intervals P in the width direction Dy and have a periodic structure. Therefore, the plurality of periodically provided members may be viewed as the metal portion 121, or the plurality of members may be viewed as the silicon portion 122, or alternatively, the plurality of the plurality of members. The member may be viewed as a set of silicon portion 122 and metal portion 121.

The metal portion 121 is formed of a metal having an action such as absorption or phase shift with respect to X-rays in order for the silicon portion 122 to function so as to transmit X-rays. As an aspect, the metal of the metal portion 121 is preferably selected to absorb X-rays. For example, a metal or a noble metal having a relatively heavy atomic weight, more specifically, for example, gold (Au) and platinum. (Platinum, Pt) or the like. In addition, the metal portion 121 has an appropriate thickness H so that, for example, X-rays can be sufficiently absorbed according to specifications. As a result, the ratio of the thickness H to the width W in the metal portion 121 (aspect ratio = thickness / width) is, for example, a high aspect ratio of 5 or more. The width W of the metal portion 121 is the length of the metal portion 121 in the width direction Dy, and the thickness H of the metal portion 121 is the length of the metal portion 121 in the normal direction (depth direction) Dz of the lattice plane DxDy. Length.

As an aspect, the grating DG functions as a diffraction grating by appropriately setting the predetermined interval P according to the wavelength of the X-ray so as to satisfy the diffraction condition for the X-ray.

Note that the metal portion 121 is not limited to a metal, and is similar to the silicon portion 122 as long as the metal portion 121 and the silicon portion 122 are different from each other and have properties corresponding to the intended use of the lattice DGa. In addition, it may be formed of an appropriate material according to the intended use of the lattice DGa.

The groove 13a is a recess formed in the other main surface of the substrate 11 facing the one main surface in order to partially reduce the thickness of the substrate 11. The groove 13a is formed on the other main surface facing the region where the lattice region 12a is formed. By forming the groove part 13a in the base material 11, the base material 11 becomes partially thin and the base material 11 becomes easy to bend. Accordingly, the lattice region 12a is easily curved by the groove 13a. Then, the base material 11 is bent to such an extent that it does not break at the groove 13a, so that the periodicity of the metal portion 121 and the periodicity of the silicon portion 122 are maintained, and in order to prevent the occurrence of vignetting, as described above, Since there is no need to reduce the size, the above-mentioned disadvantages caused by reducing the size of the conventional small lattice do not occur.

The grooves 13a are provided in the base material 11 in an appropriate number and an appropriate size (for example, width w and depth h) according to the bending amount of the base material 11, that is, the lattice surface of the lattice region 12a. In the example shown in FIG. 1, three grooves 13 a-1 to 13 a-3 are formed on the base material 11. In the example shown in FIG. 1, each of the metal portion 121 and the silicon portion 122 is a plate shape or a layer shape having a long linear shape extending in the one direction Dx on the lattice plane DxDy, and in the one direction Dx. Since it is a periodic structure having periodicity in the orthogonal width direction Dy, the groove 13a has a slit shape formed elongated along the long one direction Dx of the linear shape, and metal Each of the portion 121 and the silicon portion 122 is formed with a predetermined depth H in the normal direction Dz of the lattice plane DxDy and with a predetermined width W in the width direction Dy. It is formed with a predetermined depth h in the line direction Dz and with a predetermined width w in the width direction Dy. Accordingly, in the example shown in FIG. 1, the groove 13a is a layered recess having a long linear shape extending in the one direction Dx on the lattice plane DxDy, and is formed on the DxDz plane orthogonal to the lattice plane DxDy. A layered recess along.

Such a lattice DGa is manufactured, for example, through the following steps. More specifically, in order to manufacture the lattice DGa of the present embodiment, first, a base material 11 which is a substrate formed of silicon such as a silicon wafer is prepared (FIG. 2A).

Next, a lattice region 12a in which a plurality of members having the same shape are periodically provided is formed on one main surface of the substrate 11 (FIG. 2B, lattice region forming step). As described above, the plurality of members are the metal portion 121 and the silicon portion 122 in the present embodiment.

Such a lattice region 12a includes, for example, International Publication WO2012 / 008118, International Publication WO2012 / 008119, International Publication WO2012 / 008120, International Publication WO2012 / 0886121, and Japanese Unexamined Patent Publication No. 2012-127865. It can manufacture using the well-known method disclosed by this. For example, such a lattice includes, for example, a substrate including a first silicon layer and a second silicon layer attached to the first silicon layer and having a higher resistance than the first silicon layer (in the present embodiment). A resist layer forming step of forming a resist layer on the main surface of the second silicon layer in the base material 11), and patterning the resist layer by lithography to remove the patterned portion of the resist layer. A patterning step, an etching step of forming a slit groove by etching the second silicon layer corresponding to a portion where the resist layer is removed by a dry etching method until at least the first silicon layer is reached, and an electroforming method And an electroforming step of applying a voltage to the first silicon layer to fill the slit groove with a metal. Thus, it is manufactured. Further, for example, such a lattice region 12a is formed by a resist layer forming step of forming a resist layer on a main surface of a silicon substrate (corresponding to the base material 11 of the present embodiment), and by patterning the resist layer. A patterning process for removing the resist layer in the etched part, an etching process for etching the silicon substrate corresponding to the part from which the resist layer has been removed by a dry etching method to form a recess having a predetermined depth, and a thermal oxidation method The insulating layer forming step of forming an insulating layer on the inner surface of the concave portion in the silicon substrate, the removing step of removing the portion of the insulating layer formed at the bottom of the concave portion, and the silicon by the electroforming method It is manufactured by applying a voltage to the substrate and performing an electroforming step of filling the recess with metal.

The etching method in the etching step is preferably a Bosch process because the silicon substrate 11 can be etched substantially vertically. In this Bosch process, the SF ₆ plasma rich state and the C ₄ F ₈ plasma rich state are alternately repeated, thereby protecting the side wall in the recess formed by etching and etching the bottom surface in the recess. Is an etching method in which the process proceeds alternately.

Next, a groove 13a is formed on the other main surface opposite to the one main surface of the substrate 11 (FIG. 2C, groove forming step). Such a groove part 13a is formed by performing blade dicing with a blade so as to cut into the middle of the base material 11, for example. Further, for example, the groove 13 a is formed in a resist layer forming step of forming a resist layer on the other main surface of the silicon base material 11, as in the lattice region 12 a, and the resist in the patterned portion by patterning the resist layer. A patterning step for removing the layer, and etching for etching the silicon substrate 11 corresponding to the portion from which the resist layer has been removed by dry etching to form a recess having a predetermined depth h and a predetermined width w And the process.

By performing such a lattice region forming step and a groove forming step, the bendable lattice DGa in this embodiment shown in FIG. 1 is manufactured.

Then, for the bendable lattice DGa manufactured in this manner, after the groove forming step, in order to further align the lattice surface DxDy with a predetermined curved surface having a predetermined curvature radius, as shown in FIG. A bending step of bending the lattice plane DxDy of the lattice region 12a may be performed. In this bending step, both ends of the lattice DGa may be supported and bent. By performing this bending process, a curved grating is provided.

Since the lattice DGa and the manufacturing method thereof in the present embodiment include the groove portion 13a on the other main surface facing the one main surface on which the lattice region 12a is formed, the thickness of the base material 11 is reduced at the groove portion 13a. For this reason, the lattice DGa is easily bent at the groove portion 13a where the substrate 11 is thin. Therefore, the lattice DGa having the above configuration can be bent. In addition, since the lattice DGa having the above configuration can be bent, the periodicity of the metal part 121 and the periodicity of the silicon part 122 are maintained in the plurality of members, in this embodiment, in order to prevent the occurrence of vignetting. As described above, since it is not necessary to reduce the size of the small lattice, the above-described disadvantage caused by reducing the size of the conventional small lattice does not occur.

Next, another embodiment will be described.

(Second Embodiment)
FIG. 3 is a perspective view showing a configuration of a lattice in the second embodiment. FIG. 4 is a cross-sectional view for explaining the manufacturing process of the grating in the second embodiment.

The lattice DGb in the second embodiment further includes a holding member 14 in the lattice DGa in the first embodiment. That is, as shown in FIGS. 3 and 4C, the lattice DGb in the second embodiment is formed on the base material 11, the lattice region 12 a formed on one main surface of the base material 11, and the one main surface of the base material 11. A groove portion 13a formed on the opposite main surface and a holding member 14 are provided. Since the base material 11, the lattice region 12a, and the groove portion 13a in the lattice DGb of the second embodiment are the same as the base material 11, the lattice region 12a, and the groove portion 13a in the lattice DGa of the first embodiment, description thereof is omitted. .

When the base material 11 is divided into a plurality of base material pieces, the holding member 14 is arranged relative to each other in the plurality of base material pieces before and after the division (positional relationship of the arrangement, each position of the base material pieces). In order to maintain the mutual positional relationship), it is a member disposed on one main surface of the base material 11 including a region facing the region where the groove 13a is formed. In the example shown in FIG. 3, the holding member 14 is formed in a layer shape (sheet shape) on the entire lattice surface of the lattice region 12 a. More specifically, for example, the holding member 14 is a sheet made of a resin material having an adhesive material on one main surface, and is adhered to the entire lattice surface of the lattice region 12a by the adhesive material.

Such a lattice DGb is manufactured, for example, through the following steps. More specifically, in order to manufacture the lattice DGb of the present embodiment, first, the base material 11 is prepared (FIG. 4A), and then the lattice region 12a is based on the lattice DGa of the first embodiment. It is formed on one main surface of the material 11 (FIG. 4B, lattice region forming step).

Next, on one main surface of the base material 11 including the region facing the region where the groove 13a is formed, in this embodiment, the holding member 14 is adhered to the entire lattice surface of the lattice region 12a by the adhesive material. (FIG. 4C, holding member disposing step).

Then, similarly to the lattice DGa of the first embodiment, the groove 13a is formed on the other main surface (FIG. 4D, groove forming step).

By performing such a lattice region forming step, holding member disposing step, and groove forming step, the bendable lattice DGb in the present embodiment shown in FIG. 3 is manufactured.

Then, for the bendable grating DGb manufactured in this manner, after the groove forming step, in order to further align the grating surface DxDy with a predetermined curved surface having a predetermined radius of curvature, as shown in FIG. A bending step of bending the lattice plane DxDy of the lattice region 12a may be performed. In addition, this bending process may be bent until the base material 11 breaks.

Here, in order to maintain the bending state of the lattice DGb bent by the bending process, for example, an adhesive or an adhesive is applied to the crack (crack) CR generated in the groove portion 13a in the depth direction Dz by the bending process. A filling member such as a putty may be filled and the crack CR may be filled. The filling member is preferably a material having substantially the same properties as those of the base material 11 according to the intended use of the lattice DGb. In this embodiment, the lattice DGb is for X-rays, and the base material 11 is made of silicon. Therefore, when solidified, it is SOG (spin on glass) that becomes substantially equal to the X-ray transmittance of silicon. Is preferred.

In the above description, the holding member 14 is formed on the entire lattice surface of the lattice region 12a. However, a plurality of holding members 14 may be formed for each region of the main surface facing the region where the groove 13a is formed. Further, the holding member 14 may be disposed on the other surface of the base material 11 including at least the groove portion 13a. Alternatively, the holding member 14 includes the region facing the region where the groove portion 13a is formed. May be disposed on one main surface of the substrate 11 and on the other surface of the base material 11 including at least the groove 13a.

Since the lattice DGb and the manufacturing method thereof according to the present embodiment include the holding member 14 disposed by the holding member disposing step, even if the base material 11 is broken by the bending step, the periodicity in the plurality of members, In the present embodiment, the periodicity of the metal portion 121 and the periodicity of the silicon portion 122 can be maintained.

In the above-described embodiment, each step is performed in the order of the lattice region forming step, the holding member disposing step, and the groove forming step. For example, the lattice region forming step, the groove forming step, and the holding member disposing step are performed in this order. Each step may be performed. In the above-described embodiment, each process is performed in the order of the lattice region forming step, the holding member disposing step, the groove forming step, and the bending step. For example, the lattice region forming step, the groove forming step, the bending step, and the holding are performed. Each step may be performed in the order of the member disposing step, and for example, each step may be performed in the order of the lattice region forming step, the groove forming step, the holding member disposing step, and the bending step.

Next, another embodiment will be described.

(Third embodiment)
FIG. 5 is a perspective view showing a configuration of a lattice in the third embodiment. FIG. 6 is a cross-sectional view for explaining the manufacturing process of the grating in the third embodiment. FIG. 7 is a cross-sectional view for explaining a manufacturing process of a lattice in a modification of the third embodiment.

In the lattices DGa and DGb in the first and second embodiments, when the lattice plane DxDy of the lattice region 12a is bent by a bending process as shown in FIGS. 2D and 4E, the regions face the region where the groove 13a is formed. On the other hand, the lattices DGa and DGb formed in the region of the main surface are narrow in width, and the periodicity of the metal portion 121 and the periodicity of the silicon portion 122 may be disturbed. For this reason, the lattice DGc in the third embodiment includes the metal portion 121 or the silicon portion provided in the region of the one main surface facing the region where the groove portion 13a is formed, among the plurality of metal portions 121 or the plurality of silicon portions 122. The width W2 in the periodic direction 122 is formed so as to be wider than the width W1 of the metal portion 121 or the silicon portion 122 provided in another region.

Such a lattice DGc in the third embodiment includes, for example, as shown in FIGS. 5 and 6D, a base material 11, a lattice region 12 b formed on one main surface of the base material 11, and one of the base materials 11. In the example shown in FIGS. 5 and 6D, on the entire lattice surface of the lattice region 12b, as in the lattice DGb in the second embodiment, the groove portion 13a is formed on the other principal surface opposite to the principal surface. A holding member 14 is provided. Note that the lattice DGc in the third embodiment may not include the holding member 14 in the same manner as the lattice DGa in the first embodiment. The base material 11 and the groove 13a in the lattice DGc of the third embodiment are the same as the base material 11 and the groove 13a in the lattice DGa of the first embodiment, and the holding member 14 in the lattice DGc of the third embodiment is the first Since it is the same as the holding member 14 in the lattice DGb of the second embodiment, the description thereof is omitted.

The lattice region 12b is a region that is formed on one main surface of the base material 11 and that is provided with a plurality of members having the same shape and is opposed to a region of the plurality of metal portions 121 where the groove 13a is formed. On the other hand, the first portion except that the width W2 in the periodic direction of the metal portion 121 provided in the region of the main surface is larger than the width W1 of the metal portion 121 provided in the other region. This is the same as the lattice region 12a in the lattice DGa of the embodiment. That is, the lattice region 12b includes a metal portion 121 and a silicon portion 122 similar to the lattice region 12a in the lattice DGa of the first embodiment, and a metal portion 123 formed with a width W2 wider than the width W1 of the metal portion 121. The metal portion 123 having the width W2 is provided in a region of one main surface facing the region in which the groove 13a is formed. Since the metal portion 123 having the width W2 is the same as the metal portion 121 having the width W1 in the lattice region 12a in the lattice DGa of the first embodiment except that the width W is different, the description thereof is omitted.

Such a lattice DGc is manufactured, for example, through the following steps. More specifically, in order to manufacture the lattice DGc of this embodiment, as shown in FIG. 6, first, the base material 11 is prepared (FIG. 6A), and then the lattice region 12 b is one side of the base material 11. It is formed on the main surface (FIG. 6B, lattice region forming step). In the lattice region forming step in the third embodiment, for example, the lattice region 12b is formed instead of the lattice region 12a in the patterning step described in the lattice region forming step (FIG. 2B) of the first embodiment. Except for the point that the resist layer is patterned by a lithography method and the resist layer in the patterned portion is removed, this is the same as the method for manufacturing the lattice DGa in the first embodiment.

Then, similarly to the method of manufacturing the lattice DGb of the second embodiment, the holding member disposing step is performed (FIG. 6C), and the groove forming step is performed (FIG. 6D). In the groove forming step, for example, alignment patterning is performed by a double-sided mask aligner, and etching is performed. Alternatively, in the groove forming step, blade dicing may be performed using the alignment mark.

By performing such a lattice region forming step, a holding member disposing step, and a groove forming step, the bendable lattice DGc in this embodiment shown in FIG. 5 is manufactured.

Then, for the bendable grating DGc manufactured in this manner, after the groove forming step, in order to further align the grating surface DxDy with a predetermined curved surface having a predetermined curvature radius, as shown in FIG. A bending step of bending the lattice plane DxDy of the lattice region 12a may be performed. In addition, this bending process may be bent until the base material 11 breaks. Here, as described above, the crack (crack) CR generated in the groove portion 13a in the depth direction Dz by the execution of the bending step may be filled with the filling member to fill the crack CR.

In the grid DGc and the manufacturing method thereof according to the present embodiment, since the width W2 of the metal portion 123 is wider than the width W1 of the other metal portion 121, even if the grid plane DxDy of the grid region 12b is curved by the bending process, The disturbance of the periodicity of the portion 121 can be suppressed to a small level.

In the third embodiment described above, the depth in the normal direction of the lattice plane DxDy in the metal portion 124 provided in the region of the one main surface facing the region in which the groove 13a is formed is as shown in FIG. The depth of the other metal portion 121 may be deeper. That is, the lattice DGd according to the modification of the third embodiment is a method of the lattice plane DxDy in the metal portion 124 provided in the region of the main surface opposite to the region where the groove 13a is formed among the plurality of metal portions 121. The lattice region 12c is formed so that the depth in the line direction is deeper than the depth of the metal portion 121 provided in another region. As shown in FIG. 7, the lattice DGd can be manufactured by the same steps as those shown in FIG. In the lattice region forming step (FIG. 7B), in the etching method, the metal portion 123 has a depth that is different from that of the other metal portion 121 due to a so-called microloading effect, which is a phenomenon in which the etching rate is reduced as the pattern width is reduced. It is formed to be deeper.

In such a lattice DGd and the manufacturing method thereof, since the depth of the metal portion 124 is deeper than the depth of the other metal portion 121, even if the base material 11 is broken by the bending process, it can be broken at this portion. Can be predicted. 7D, even if the position of the groove 13a and the position of the deeper metal portion 124 are slightly shifted as shown in FIG. 7D, the thickness of the base material 11 in this portion is thinner. As shown, this part can be preferentially broken. Therefore, such a lattice DGd and its manufacturing method can design the lattice DGd in consideration of breakage, and can realize the performance as designed more reliably.

Next, another embodiment will be described.

(Fourth embodiment)
FIG. 8 is a cross-sectional view showing the configuration of the grating in the fourth embodiment. The gratings DGa to DGd in the first to third embodiments are bent so that the grating surface DxDy becomes a concave surface when the bending process is performed, but the bending process is performed as shown in FIG. 8A. In this case, the grating surface DxDy may be bent so as to be a convex surface. FIG. 8A shows an example of the lattice DGb of the second embodiment.

In addition, in the case where such a lattice plane DxDy is bent so as to be a convex surface, a groove 13b having a V-shaped cross section is preferable as shown in FIG. 8B instead of the groove 13a. Such a groove 13b having a V-shaped cross section can be formed by anisotropic etching or dicing using a blade having a triangular cross section. By using the groove 13b, when the lattice surface DxDy is bent so as to be a convex surface, the tapered side surfaces of the groove 13b can be brought into contact with each other, and there is substantially no gap.

The gratings DG (DGa to DGd) in the first to fourth embodiments described above are diffraction gratings for X-rays. However, the gratings DG (DGa to DGd) are not limited to those for X-rays. It may be a diffraction grating for waves of other wavelengths.

In the above-described lattices DG (DGa to DGd) of the first to fourth embodiments, the metal portion 121 is formed between the silicon portions 122 adjacent to each other, but the space portion (gap portion, gap portion) is formed. It may be. In such a grating DG using a space portion instead of the metal portion 121, the predetermined interval P is set to a predetermined wavelength (for example, an X-ray wavelength) due to a difference in refractive index between the silicon portion 122 and the space portion. By appropriately setting according to this, it functions as a diffraction grating, for example, a phase type diffraction grating. Here, the refractive index of the silicon portion 122 is a refractive index of silicon (Si), and the space portion is a refractive index of a predetermined gas (for example, air).

In the lattice DG (DGa to DGd) of the first to fourth embodiments described above, the one direction Dx in which the metal portions 121 and 123, the silicon portion 122, and the groove portions 13a and 13b extend coincides with the cleavage direction of the base material 11. It is preferable to do. For example, when the base material 11 is a (100) silicon substrate, it is cleaved in the [110] direction or the [1-10] direction, so the one direction Dx coincides with the [110] direction or the [1-10] direction. It is preferable to do. Such a lattice DG can be broken along the metal parts 121 and 123, the silicon part 122 and the groove parts 13a and 13b even if the base material 11 is broken by a bending process, and the breaking direction can be predicted. . Therefore, such a lattice DG and a method for manufacturing the lattice DG can design the lattice DG in consideration of breakage, and can realize the performance as designed more reliably.

In the lattice DG (DGa to DGd) of the first to fourth embodiments described above, the toughness of the holding member 14 is preferably higher than the toughness of the base material 11. Such a lattice DG and a method of manufacturing the lattice DG can prevent the holding member 14 from breaking before the base material 11 is broken, and even if the base material 11 is broken by a bending process, the metal portion 121 is broken. , 123 and the reliability of the point that the periodicity of the silicon portion 122 can be maintained.

Further, in the lattice DG (DGa to DGd) of the first to fourth embodiments described above, the X-ray absorption rate of the holding member 14 is preferably smaller than the X-ray absorption rate of the base material 11. Such a grating DG and the method for manufacturing the grating DG can reduce the influence of the holding member 14 on the grating when the grating DG is used for X-rays.

Next, an example will be described.

(Example)
FIG. 9 is a diagram for explaining an embodiment of the lattice. As an example of the lattice DGa of the first embodiment, as shown in FIG. 9, for example, a lattice region that is a square of 110 mm is formed on one main surface of an 8-inch silicon wafer having a thickness of 400 μm. FIG. 9A). This lattice region is an absorption type lattice composed of a gold portion (= width 2.65 μm) and a silicon portion (= width 2.65 μm) having a period of 5.3 μm and a depth of 100 μm. Next, with the blade dicing apparatus, as shown in FIG. 9B, both sides of the lattice region (one set of opposite sides of the four sides of the lattice region) were cut off, and the lattice was cut out. Thereafter, the cut out lattice was cut into a depth of 250 μm from the other main surface where the lattice region was not formed, using a blade dicing apparatus, thereby forming a groove (FIG. 9C). As a result, a lattice region having a depth of 100 μm is formed on a silicon wafer having a thickness of 400 μm and a groove portion having a thickness of 250 μm is formed, so that the thickness of the silicon wafer on which the groove portion is formed becomes 50 μm. Then, this is an arc-shaped portion remaining outside the one-direction Dx in which the gold portion, the silicon portion, and the groove portion extend (the other set of the other four sides of the lattice region that are not cut is opposed to each other). The arc-shaped portions remaining on the outer sides of both sides were bent along an arc having a radius of 1.4 m while being held on both sides.

Although not shown, as an example of the lattice DGb of the second embodiment, for example, a lattice region having a square of 110 mm is formed on one main surface of an 8-inch silicon wafer having a thickness of 400 μm. This grating region is a phase type grating having a space portion (= width 2.15 μm) and a silicon portion (= width 2.15 μm) having a period of 4.3 μm and a depth of 18 μm. Next, with a blade dicing apparatus, both sides of the lattice region were cut off, and the lattice was cut out. Next, an adhesive PET film (adhesive polyethylene terephthalate film) having a thickness of 90 μm was stuck as a holding member on the entire lattice region. Thereafter, this cut out lattice was cut into a depth of 332 μm from the other main surface where the lattice region was not formed with the same blade dicing apparatus to form a groove (FIG. 9C). As a result, a lattice region having a depth of 18 μm and a groove portion having a depth of 332 μm are formed on a silicon wafer having a thickness of 400 μm, so that the thickness of the silicon wafer having the groove portion becomes 50 μm. Next, it was broken at the groove by being pressed against a jig having a curved surface with a radius of 50 cm. Here, the one direction Dx in which the gold part, the silicon part, and the groove part extend is preferably coincident with the cleavage direction of the silicon wafer. This was bent along an arc having a radius of 1.1 m while holding the arc-shaped portions remaining on the outer side in one direction Dx in which the gold portion, the silicon portion and the groove portion extend in the lattice region.

Although not shown, as an example of the grating DGc of the third embodiment, for example, a space portion (= width 2.15 μm) and a silicon portion (== period of 2.5 μm and depth 18 μm) In the case of the lattice region having a width of 2.15 μm, that is, the width of the space portion: the width of the silicon portion = 1: 1, the groove portion is arranged along a curved surface having a radius of 50 cm. If only the period corresponding to the part is 2.53 μm, the period corresponding to the groove part is approximately 2.5 μm.

(Fifth and sixth embodiments; Talbot interferometer and Talbot-Lau interferometer)
The grating DG (DGa to DGd) and the grating unit of the above embodiment can be suitably used for an X-ray Talbot interferometer and a Talbot-Lau interferometer as an application example. An X-ray Talbot interferometer and an X-ray Talbot-low interferometer using the grating DG and the grating unit will be described.

FIG. 10 is a perspective view showing a configuration of an X-ray Talbot interferometer in the fifth embodiment. FIG. 11 is a top view showing a configuration of an X-ray Talbot-Lau interferometer in the sixth embodiment.

As shown in FIG. 10, an X-ray Talbot interferometer 200A according to the embodiment includes an X-ray source 201 that emits X-rays having a predetermined wavelength, and a phase type that diffracts X-rays emitted from the X-ray source 201. The first and second diffraction gratings 202 and 203 include a first diffraction grating 202 and an amplitude-type second diffraction grating 203 that forms an image contrast by diffracting the X-rays diffracted by the first diffraction grating 202. Are set to the conditions constituting the X-ray Talbot interferometer. Then, the X-ray having the image contrast caused by the second diffraction grating 203 is detected by, for example, an X-ray image detector 205 that detects the X-ray. In the X-ray Talbot interferometer 200A, at least one of the first diffraction grating 202 and the second diffraction grating 203 is the grating DG or the grating unit. The lattice unit includes a plurality of lattices (small lattices, sub-lattices, lattice elements) arranged so as to form one lattice plane, and at least one of the plurality of lattices is the first to the above-described first to It is one of the lattices DG in the fourth embodiment.

The conditions constituting the Talbot interferometer 200A are expressed by the following equations 1 and 2. Equation 2 assumes that the first diffraction grating 202 is a phase type diffraction grating.
l = λ / (a / (L + Z1 + Z2)) (Formula 1)
Z1 = (m + 1/2) × (d ² / λ) (Formula 2)
Here, l is the coherence distance, λ is the wavelength of X-rays (usually the center wavelength), and a is the aperture diameter of the X-ray source 201 in the direction substantially perpendicular to the diffraction member of the diffraction grating. Yes, L is the distance from the X-ray source 201 to the first diffraction grating 202, Z1 is the distance from the first diffraction grating 202 to the second diffraction grating 203, and Z2 is from the second diffraction grating 203 The distance to the X-ray image detector 205, m is an integer, and d is the period of the diffraction member (period of diffraction grating, grating constant, distance between centers of adjacent diffraction members, the pitch P). .

In the X-ray Talbot interferometer 200A having such a configuration, X-rays are irradiated from the X-ray source 201 toward the first diffraction grating 202. This irradiated X-ray produces a Talbot effect at the first diffraction grating 202 to form a Talbot image. This Talbot image is acted on by the second diffraction grating 203 to form an image contrast of moire fringes. This image contrast is detected by the X-ray image detector 205.

The Talbot effect means that when light enters the diffraction grating, the same image as the diffraction grating (self-image of the diffraction grating) is formed at a certain distance. Good, this self-image is called the Talbot image. When the diffraction grating is a phase type diffraction grating, the Talbot distance L is Z1 represented by the above formula 2 (L = Z1). In the Talbot image, an inverted image appears at an odd multiple of L (= (2m + 1) L, m is an integer), and a normal image appears at an even multiple of L (= 2 mL).

Here, when the subject S is arranged between the X-ray source 201 and the first diffraction grating 202, the moire fringes are modulated by the subject S, and the modulation amount is caused by the refraction effect by the subject S. It is proportional to the angle at which the X-ray is bent. For this reason, the subject S and its internal structure are detected by analyzing the moire fringes.

In the Talbot interferometer 200A configured as shown in FIG. 10, the X-ray source 201 is a single point light source (point wave source), and such a single point light source has a single slit (single slit). The X-ray radiated from the X-ray source 201 passes through the single slit of the single slit plate and passes through the subject S for the first diffraction. Radiated toward the grating 202. The slit is an elongated rectangular opening extending in one direction.

On the other hand, the Talbot-Lau interferometer 200B includes an X-ray source 201, a multi-slit plate 204, a first diffraction grating 202, and a second diffraction grating 203, as shown in FIG. That is, the Talbot-Lau interferometer 200B further includes a multi-slit plate 204 in which a plurality of slits are formed in parallel on the X-ray emission side of the X-ray source 201 in addition to the Talbot interferometer 200A shown in FIG. Is done.

The multi slit plate 204 may be the lattice DG or the lattice unit in the first to fourth embodiments described above. By configuring the multi-slit plate 204 with the lattice DG or the lattice unit in the first to fourth embodiments described above, X-rays can be transmitted substantially parallel to the slits (the plurality of silicon portions 122). Since the intensities of the X-rays transmitted through the slits can be made substantially uniform, the multi-slit plate 204 can use the X-rays emitted from the X-ray source 201 as a better multi-light source.

By using the Talbot-Lau interferometer 200B, the X-ray dose radiated toward the first diffraction grating 202 through the subject S is increased compared to the Talbot interferometer 200A, so that a better moiré fringe can be obtained. It is done.

Examples of the first diffraction grating 202, the second diffraction grating 203, and the multi-slit plate 204 used in the Talbot interferometer 200A and the Talbot-low interferometer 200B are as follows. In these examples, the silicon portion 122 and the metal portion 121 are formed with the same width, and the metal portion 121 is formed of gold.

As an example, the distance R1 from the X-ray source 201 or the multi-slit plate 204 to the first diffraction grating 202 is 1.1 m, and the distance R2 from the X-ray source 201 or the multi-slit plate 204 to the second diffraction grating 203 is In the case of 1.4 m, the first diffraction grating 202 has a pitch P of 4.5 μm, the silicon portion 122 has a thickness of 18 μm, and the second diffraction grating 203 has a pitch P of 5.mu.m. 3 μm, the thickness of the metal portion 121 is 100 μm (aspect ratio = 100 / 2.65), and the multi-slit plate 204 has a pitch P of 22.8 μm and a thickness of the metal portion 121. Is 100 μm.

(Seventh embodiment; X-ray imaging apparatus)
The grating DG and the grating unit can be used for various optical devices, but can be suitably used for an X-ray imaging device, for example. In particular, an X-ray imaging apparatus using an X-ray Talbot interferometer treats X-rays as waves and detects a phase shift of the X-rays caused by passing through the subject to obtain a phase contrast method for obtaining a transmission image of the subject. Compared with an absorption contrast method that obtains an image in which the magnitude of X-ray absorption by a subject is a contrast, an improvement in sensitivity of about 1000 times is expected, so that the X-ray irradiation dose is, for example, 1/100 to 1 / 1000 has the advantage that it can be reduced. In the present embodiment, an X-ray imaging apparatus including an X-ray Talbot interferometer using a grating unit including the grating DG will be described.

FIG. 12 is an explanatory diagram showing the configuration of the X-ray imaging apparatus according to the seventh embodiment. In FIG. 12, an X-ray imaging apparatus 300 includes an X-ray imaging unit 301, a second diffraction grating 302, a first diffraction grating 303, and an X-ray source 304. Furthermore, in this embodiment, the X-ray source An X-ray power supply unit 305 that supplies power to 304, a camera control unit 306 that controls the imaging operation of the X-ray imaging unit 301, a processing unit 307 that controls the overall operation of the X-ray imaging apparatus 300, and an X-ray power source And an X-ray control unit 308 that controls the X-ray emission operation of the X-ray source 304 by controlling the power supply operation of the unit 305.

The X-ray source 304 is a device that emits X-rays by being supplied with power from the X-ray power supply unit 305 and emits X-rays toward the first diffraction grating 303. For example, the X-ray source 304 emits X-rays when a high voltage supplied from the X-ray power supply unit 305 is applied between the cathode and the anode, and electrons emitted from the cathode filament collide with the anode. Device.

The first diffraction grating 303 is a transmission type diffraction grating that generates a Talbot effect by X-rays emitted from the X-ray source 304. The first diffraction grating 303 is, for example, the grating unit DG of the above-described embodiment. The first diffraction grating 303 is configured so as to satisfy the conditions for generating the Talbot effect, and is a grating sufficiently coarser than the wavelength of X-rays emitted from the X-ray source 304, for example, a grating constant (period of the diffraction grating). It is a phase type diffraction grating in which d is about 20 times or more the wavelength of the X-ray. The first diffraction grating 303 may be an amplitude type diffraction grating.

The second diffraction grating 302 is a transmission-type amplitude diffraction grating that is disposed at a position approximately L Talbot distance L away from the first diffraction grating 303 and diffracts the X-rays diffracted by the first diffraction grating 303. Similarly to the first diffraction grating 303, the second diffraction grating 302 is also the grating DG or the grating unit of the above-described embodiment, for example.

In the first diffraction grating 303, the one or more gratings DG constituting the first diffraction grating 303 have X-rays so that the normal passing through the center of the light receiving surface passes through the radiation source of the X-ray source 304 as a point light source. It is preferably arranged along a virtual cylindrical surface with a virtual line passing through the radiation source of the source 304 as a central axis, and in the second diffraction grating 302, one or more constituting the second diffraction grating 302 The grid DG is a virtual line centered on a virtual line passing through the radiation source of the X-ray source 304 so that a normal passing through the center of the light receiving surface passes through the radiation source of the X-ray source 304 as a point light source. It is preferable that they are arranged along the cylindrical surface. Each of the first and second diffraction gratings 303 and 302 has a radius of curvature of about 1 m.

And these 1st and 2nd diffraction gratings 303 and 302 are set to the conditions which comprise the Talbot interferometer represented by the above-mentioned Formula 1 and Formula 2.

The X-ray imaging unit 301 is an apparatus that captures an X-ray image diffracted by the second diffraction grating 302. The X-ray imaging unit 301 is, for example, a flat panel detector (FPD) including a two-dimensional image sensor in which a thin film layer including a scintillator that absorbs X-ray energy and emits fluorescence is formed on a light receiving surface, and incident photons. An image intensifier unit that converts the electrons into electrons on the photocathode, doubles the electrons on the microchannel plate, and causes the doubled electrons to collide with phosphors to emit light, and the output light of the image intensifier unit An image intensifier camera including a two-dimensional image sensor.

The processing unit 307 is a device that controls the entire operation of the X-ray imaging apparatus 300 by controlling each unit of the X-ray imaging apparatus 300. For example, the processing unit 307 includes a microprocessor and its peripheral circuits, and is functionally An image processing unit 371 and a system control unit 372 are provided.

The system control unit 372 controls the X-ray emission operation in the X-ray source 304 via the X-ray power source unit 305 by transmitting and receiving control signals to and from the X-ray control unit 308, and the camera control unit 306. The imaging operation of the X-ray imaging unit 301 is controlled by transmitting and receiving control signals between the X-ray imaging unit 301 and the X-ray imaging unit 301. Under the control of the system control unit 372, X-rays are emitted toward the subject S, an image generated thereby is captured by the X-ray imaging unit 301, and an image signal is input to the processing unit 307 via the camera control unit 306. The

The image processing unit 371 processes the image signal generated by the X-ray imaging unit 301 and generates an image of the subject S.

Next, the operation of the X-ray imaging apparatus of this embodiment will be described. For example, the subject S is placed on an imaging table including the X-ray source 304 inside (rear surface), so that the subject S is disposed between the X-ray source 304 and the first diffraction grating 303, and the X-ray imaging apparatus 300. When the user (operator) instructs the subject S to capture an image of the subject S, the system control unit 372 of the processing unit 307 controls the X-ray control unit 308 to emit X toward the subject S. Is output. With this control signal, the X-ray control unit 308 causes the X-ray power supply unit 305 to supply power to the X-ray source 304, and the X-ray source 304 emits X-rays and irradiates the subject S with X-rays.

The irradiated X-ray passes through the first diffraction grating 303 through the subject S, is diffracted by the first diffraction grating 303, and is a self-image of the first diffraction grating 303 at a position away from the Talbot distance L (= Z1). A Talbot image T is formed.

The formed X-ray Talbot image T is diffracted by the second diffraction grating 302 to generate moire and form moire fringe images. The moire fringe image is picked up by the X-ray imaging unit 301 whose exposure time is controlled by the system control unit 372, for example.

The X-ray imaging unit 301 outputs the image signal of the moire fringe image to the processing unit 307 via the camera control unit 306. This image signal is processed by the image processing unit 371 of the processing unit 307.

Here, since the subject S is disposed between the X-ray source 304 and the first diffraction grating 303, the X-rays that have passed through the subject S are out of phase with the X-rays that do not pass through the subject S. For this reason, the X-rays incident on the first diffraction grating 303 include distortion in the wavefront, and the Talbot image T is deformed accordingly. For this reason, the moire fringes of the image generated by the superimposition of the Talbot image T and the second diffraction grating 302 are modulated by the subject S, and the X-rays are bent by the refraction effect of the subject S. Proportional to angle. Therefore, the subject S and its internal structure can be detected by analyzing the moire fringes. In addition, by imaging the subject S from a plurality of angles, a tomographic image of the subject S can be formed by X-ray phase CT (computed tomography).

Since the first and second diffraction gratings 303 and 302 of this embodiment include the bendable grating DG in the above-described embodiment, a plurality of gratings can be arranged along the curved surface, and both ends of the grating The so-called vignetting described above that occurs in the region of (adjacent portions of the lattices adjacent to each other) can be reduced. Therefore, such an X-ray imaging apparatus 300 can reduce noise caused by the vignetting and can obtain a clearer X-ray image. Since such an X-ray imaging apparatus includes a bendable grating DG, the periodicity in the metal part 121 and the silicon part 122 is maintained, and in order to prevent the occurrence of the vignetting, Since there is no need to reduce the size, the above-mentioned disadvantages caused by reducing the size of the conventional small lattice do not occur.

In the X-ray imaging apparatus 300 described above, a Talbot interferometer is configured by the X-ray source 304, the first diffraction grating 303, and the second diffraction grating 302. The Talbot-Lau interferometer may be configured by further arranging the grating DG or the grating unit in the above-described embodiment. The lattice DG as the multi slit is set to have a radius of curvature of about 2 to 3 cm. By using such a Talbot-Lau interferometer, the X-ray dose irradiated to the subject S can be increased as compared with the case of a single slit, a better moire fringe can be obtained, and the subject S with higher accuracy can be obtained. An image is obtained.

In the X-ray imaging apparatus 300 described above, the subject S is disposed between the X-ray source 304 and the first diffraction grating 303, but the subject S is disposed between the first diffraction grating 303 and the second diffraction grating 302. May be arranged.

Further, in the above-described X-ray imaging apparatus 300, an X-ray image is captured by the X-ray imaging unit 301 and electronic data of the image is obtained, but may be captured by an X-ray film.

This specification discloses various modes of technology as described above, and the main technologies are summarized below.

A diffraction grating according to one aspect is configured to face a base material, a grating region formed on one main surface of the base material, in which a plurality of members having the same shape are periodically provided, and the one main surface of the base material Each of the plurality of members has a long linear shape extending in one direction on the one main surface, and the groove portion extends along the one direction. It is long.

Since such a diffraction grating has a groove on the other main surface facing the one main surface on which the grating region is formed, the thickness of the base material is reduced at the groove. For this reason, such a diffraction grating can be easily bent in a periodic direction perpendicular to the one direction at the groove portion, and can be bent at the groove portion. Since such a diffraction grating can be bent, the periodicity of the plurality of members is maintained, and it is not necessary to reduce the size of the small grating as described above in order to prevent the occurrence of vignetting. Therefore, the above-described disadvantages caused by reducing the size of the conventional small lattice do not occur.

In another aspect, in the diffraction grating described above, a plurality of the base materials are provided on one main surface of the base material including at least the grating region, or on the other main surface of the base material including at least the groove. And a holding member for holding the mutual positional relationship between the plurality of base material pieces before and after the division.

Since such a diffraction grating includes the holding member, the periodicity of the plurality of members can be maintained even if the base material is broken by a bending process.

In another aspect, in the above-described diffraction grating, a periodic direction orthogonal to the one direction in a member provided in the region of the one main surface facing the region in which the groove portion is formed among the plurality of members. The width is wider than the width of the other members of the plurality of members.

In such a diffraction grating, the width of the periodic direction perpendicular to the one direction in the member provided in the region of the one main surface facing the region where the groove is formed is wider than the width of the other member. Even when the lattice plane is curved, the periodic disturbance in the plurality of members can be kept small.

In another aspect, in the above-described diffraction grating, a depth in a normal direction of the grating surface in the member provided in the region of the one main surface facing the region in which the groove portion is formed among the plurality of members. The depth is deeper than the depth of the other members of the plurality of members.

In such a diffraction grating, since the depth in the normal direction of the grating surface of the member provided in the region of the one main surface facing the region where the groove is formed is deeper than the depth of the other members, Even when the base material is broken by bending, it can be broken at this portion, and the broken portion can be predicted. Therefore, such a diffraction grating can be designed in consideration of breakage, and the performance as designed can be more reliably realized.

In another aspect, in the above-described diffraction grating, the one direction coincides with the cleavage direction of the substrate.
Since such a diffraction grating is formed so that the groove portion coincides with the cleavage direction of the substrate, even if the substrate is broken by bending, it can be broken along the plurality of members and groove portions. And the direction of breakage can be predicted. Therefore, such a diffraction grating can be designed in consideration of breakage, and the performance as designed can be more reliably realized.

In another aspect, in the above-described diffraction grating, the toughness of the holding member is higher than the toughness of the base material.

Since such a diffraction grating has a toughness of the holding member higher than that of the base material, the holding member can be prevented from breaking before the base material breaks. However, the reliability that the periodicity in the plurality of members can be maintained is improved.

In another aspect, in the above-described diffraction grating, the X-ray absorption rate of the holding member is smaller than the X-ray absorption rate of the base material.

Such a diffraction grating can reduce the influence of the holding member on the grating when the grating is used for X-rays because the X-ray absorption rate of the holding member is smaller than the X-ray absorption rate of the base material. .

A method of manufacturing a diffraction grating according to one aspect includes a grating region forming step in which a grating region in which a plurality of members having the same shape are periodically provided is formed on one main surface of a base material, and one main surface of the base material A groove portion forming step of forming a groove portion on the other main surface facing each other, each of the plurality of members has a long linear shape extending in one direction on the one main surface, and the groove portion is It is long along the direction. And in another one aspect | mode, the said base material is a silicon wafer in the manufacturing method of the above-mentioned diffraction grating, Preferably.

In such a method of manufacturing a diffraction grating, the grating includes a groove portion on the other main surface opposite to the one main surface on which the grating region is formed. Therefore, the thickness of the base material is reduced at the groove portion. For this reason, a grating | lattice becomes easy to bend in the periodic direction orthogonal to the said one direction in the part of a groove part. Therefore, such a manufacturing method can manufacture a bendable grid. Since the diffraction grating manufactured by such a manufacturing method can be bent, the periodicity of the plurality of members is maintained, and the size of the small grating is prevented as described above in order to prevent the occurrence of vignetting. Therefore, the above-mentioned disadvantage caused by reducing the size of the conventional small lattice does not occur.

In another aspect, the above-described diffraction grating manufacturing method further includes a bending step of bending the grating region. Such a method of manufacturing a diffraction grating can provide a curved grating.

In another aspect, the above-described manufacturing method of the diffraction grating includes the base material including at least one main surface of the base material including a region facing the region where the groove portion is formed or at least the groove portion. A holding member for disposing a holding member for holding the mutual arrangement relationship of the plurality of base material pieces before and after the division when the base material is divided into a plurality of base material pieces on the other surface of A disposing step is further provided. And in another one aspect | mode, when the said bending process is included in the manufacturing method of the above-mentioned diffraction grating, the said bending process may be bent until the said base material fractures | ruptures.

In such a manufacturing method, each step may be performed in the order of the lattice region forming step, the holding member disposing step, and the groove forming step, or each of the lattice region forming step, the groove forming step, and the holding member disposing step in this order. The steps may be performed, or the lattice region forming step, the groove forming step, the bending step, and the holding member disposing step may be performed in this order, or the lattice region forming step, the groove forming step, and the holding member disposing step. Each step may be performed in the order of the setting step and the bending step, or each step may be performed in the order of the lattice region forming step, the holding member disposing step, the groove forming step, and the bending step.

Such a method for manufacturing a diffraction grating includes a holding member arranged in the holding member arranging step, so that the periodicity in the plurality of members is maintained even when the base material is broken in the bending step. be able to.

Further, in another aspect, in the above-described diffraction grating manufacturing method, in the plurality of members, the member provided in the region of the one main surface facing the region where the groove portion is formed is in the one direction. The width in the orthogonal periodic direction is wider than the width of the other members among the plurality of members.

In such a method of manufacturing a diffraction grating, the width of the periodic direction perpendicular to the one direction in the member provided in the region of the one main surface facing the region where the groove is formed is larger than the width of the other member. Since it is wide, even when the lattice plane of the lattice region is curved by the bending process, it is possible to suppress the periodic disturbance in the plurality of members.

According to another aspect, in the above-described diffraction grating manufacturing method, the grating surface of the member provided in the region of the one main surface facing the region where the groove portion is formed among the plurality of members. The depth in the normal direction is deeper than the depth of the other members among the plurality of members.

In such a method of manufacturing a diffraction grating, the depth in the normal direction of the grating surface of the member provided in the region of the one main surface facing the region where the groove is formed is deeper than the depth of other members. Therefore, even if the base material is broken by the bending process, it can be broken at this portion, and the broken portion can be predicted. Therefore, such a method of manufacturing a diffraction grating can design a grating in consideration of breakage, and can realize performance as designed more reliably.

Also, in another aspect, in the above-described diffraction grating manufacturing method, the one direction coincides with the cleavage direction of the base material.

In such a method of manufacturing a diffraction grating, the groove is formed so as to coincide with the cleavage direction of the base material. Therefore, even if the base material is broken by a bending process, the groove is formed along the plurality of members and groove parts. It can be ruptured and the rupture direction can be predicted. Therefore, such a method of manufacturing a diffraction grating can design a grating in consideration of breakage, and can realize performance as designed more reliably.

In another aspect, in the above-described diffraction grating manufacturing method, the toughness of the holding member is higher than the toughness of the base material.

In such a method for manufacturing a diffraction grating, since the toughness of the holding member is higher than the toughness of the base material, it is possible to prevent the holding member from breaking before the base material breaks. The reliability of the point that the periodicity in the plurality of members can be maintained even when the material breaks.

In another aspect, in the above-described method for manufacturing a diffraction grating, the X-ray absorption rate of the holding member is smaller than the X-ray absorption rate of the base material.

Such a diffraction grating manufacturing method reduces the influence of the holding member on the grating when the grating is used for X-rays because the X-ray absorption rate of the holding member is smaller than the X-ray absorption rate of the substrate. be able to.

A lattice unit according to another aspect is a lattice unit including a plurality of lattices arranged so as to form one lattice plane, and at least one of the plurality of lattices is any of the above-described ones. This is a diffraction grating.

According to this configuration, a grating unit including the diffraction grating is provided. Since such a grating unit includes a bendable diffraction grating, a plurality of gratings can be arranged along the curved surface, and the above-described occurrence occurs in the region of both ends of the grating (adjacent portions of the gratings adjacent to each other). The so-called vignetting can be reduced. Further, since such a grating unit includes a bendable diffraction grating, the periodicity of the plurality of members is maintained, and the size of the small grating is reduced as described above in order to prevent the occurrence of vignetting. Since it is not necessary, the above-mentioned disadvantages caused by reducing the size of the conventional small lattice are not caused.

An X-ray imaging apparatus according to another aspect includes an X-ray source that emits X-rays, a Talbot interferometer or a Talbot-low interferometer that is irradiated with X-rays emitted from the X-ray source, and the Talbot interference. And an X-ray image pickup device that captures an X-ray image by a Talbot-Lau interferometer, and the Talbot interferometer or Talbot-Lau interferometer includes any one of the above-described diffraction gratings and the above-described grating unit. At least one of them.

According to this configuration, an X-ray imaging apparatus including the diffraction grating is provided. Since such an X-ray imaging apparatus includes a bendable diffraction grating, a plurality of gratings can be arranged along the curved surface, and the above-described occurrence occurs in the region of both ends of the grating (adjacent portions of the gratings adjacent to each other). The so-called vignetting can be reduced. Therefore, such an X-ray imaging apparatus can reduce noise caused by the vignetting and can obtain a clearer X-ray imaging image. Since such an X-ray imaging apparatus includes a bendable diffraction grating, the periodicity of the plurality of members is maintained, and the size of the small grating is reduced as described above in order to prevent the occurrence of vignetting. Since there is no need to reduce the size, the above-mentioned disadvantages caused by reducing the size of the conventional small lattice do not occur.

This application is based on Japanese Patent Application No. 2012-193163 filed on September 3, 2012, the contents of which are included in the present application.

In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

According to the present invention, a diffraction grating, a diffraction grating manufacturing method, a grating unit, and an X-ray imaging apparatus can be provided.

Claims (17)

1. A substrate;
   A lattice region formed on one main surface of the base material and periodically provided with a plurality of members having the same shape;
   A groove formed on the other main surface opposite to the one main surface of the substrate,
   Each of the plurality of members has a long linear shape extending in one direction on the one main surface,
   The groove is elongate along the one direction.
2. When the base material is divided into a plurality of base material pieces on one main surface of the base material including at least the lattice region or on the other main surface of the base material including at least the groove portion, the splitting is performed. The diffraction grating according to claim 1, further comprising a holding member for holding the mutual arrangement relationship of the plurality of base material pieces before and after the step.
3. Among the plurality of members, the width in the periodic direction orthogonal to the one direction in the member provided in the region of the one main surface facing the region where the groove is formed is the other member of the plurality of members. The diffraction grating according to claim 1, wherein the diffraction grating is wider than.
4. Of the plurality of members, the depth in the normal direction of the lattice plane in the member provided in the region of the one main surface facing the region in which the groove is formed is the other of the plurality of members. The diffraction grating according to claim 3, wherein the diffraction grating is deeper than a depth of the member.
5. The diffraction grating according to any one of claims 1 to 4, wherein the one direction coincides with a cleavage direction of the base material.
6. The diffraction grating according to any one of claims 2 to 5, wherein the toughness of the holding member is higher than the toughness of the base material.
7. The diffraction grating according to claim 2, wherein an X-ray absorption rate of the holding member is smaller than an X-ray absorption rate of the base material.
8. A lattice region forming step in which a lattice region in which a plurality of members having the same shape are periodically provided is formed on one main surface of the substrate;
   A groove portion forming step of forming a groove portion on the other main surface opposite to the one main surface of the base material,
   Each of the plurality of members has a long linear shape extending in one direction on the one main surface,
   The method for manufacturing a diffraction grating, wherein the groove is elongated along the one direction.
9. The method of manufacturing a diffraction grating according to claim 8, further comprising a bending step of bending the grating region.
10. When the base material is divided into a plurality of base material pieces on one main surface of the base material including at least the lattice region or on the other surface of the base material including at least the groove portion, the splitting is performed. 10. The diffraction grating according to claim 8, further comprising a holding member disposing step of disposing a holding member for maintaining the mutual arrangement relationship of the plurality of base material pieces before and after the step. Manufacturing method.
11. Among the plurality of members, the width in the periodic direction orthogonal to the one direction in the member provided in the region of the one main surface facing the region where the groove is formed is the other member of the plurality of members. The method of manufacturing a diffraction grating according to claim 8, wherein the diffraction grating is wider than the width of the diffraction grating.
12. Of the plurality of members, the depth in the normal direction of the lattice plane in the member provided in the region of the one main surface facing the region in which the groove is formed is the other of the plurality of members. The method for manufacturing a diffraction grating according to claim 11, wherein the depth is greater than a depth of the member.
13. The one direction coincides with the cleavage direction of the substrate;
    The method for manufacturing a diffraction grating according to any one of claims 8 to 12, wherein:
14. 14. The method of manufacturing a diffraction grating according to claim 8, wherein the toughness of the holding member is higher than the toughness of the base material.
15. The method for manufacturing a diffraction grating according to claim 8, wherein an X-ray absorption rate of the holding member is smaller than an X-ray absorption rate of the base material.
16. A grid unit comprising a plurality of grids arranged to form one grid plane,
    The grating unit according to claim 1, wherein at least one of the plurality of gratings is the diffraction grating according to claim 1.
17. An X-ray source emitting X-rays;
    A Talbot interferometer or a Talbot-low interferometer irradiated with X-rays emitted from the X-ray source;
    An X-ray imaging device that captures an X-ray image by the Talbot interferometer or the Talbot-Lau interferometer,
    The Talbot interferometer or the Talbot-Lau interferometer includes at least one of the diffraction grating according to any one of claims 1 to 7 and the grating unit according to claim 16. A featured X-ray imaging apparatus.

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