JP6149343B2 - Grating and grating unit and X-ray imaging apparatus - Google Patents

Description

The present invention, grating disposed members having the same shape as each other periodically, before Symbol grating multiple lined grid units, and relates to an X-ray imaging apparatus including the grating and the grating unit.

  Diffraction gratings are used in optical systems of various devices as spectroscopic elements having a large number of parallel periodic structures, and in recent years, application to X-ray imaging devices has also 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 or ultraviolet diffraction gratings can be manufactured relatively easily because near-infrared, visible and ultraviolet light is sufficiently absorbed by very thin metals. 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 generally have very little absorption by substances, and the phase change is not so great. 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 X-ray diffraction grating, when the transmission portion, the absorption portion, and the phase change portion are formed with a regular structure with a constant width of several μm to several tens of μm, the thickness of the gold portion with respect to the width is reduced. 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 an X-ray diagnostic apparatus, it has a certain size, for example, a square having a side of 20 cm or more (□ 20 cm or more) because of the diagnostic area to be diagnosed at one time. A size is necessary.

  When a diffraction grating having such a size is used, 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. Thus, X-rays are incident obliquely in the peripheral region of the diffraction grating. As a result, in the peripheral region, X-rays do not pass through the diffraction grating, and so-called vignetting occurs. Therefore, in order to follow the wavefront, the diffraction grating is formed in a shape along the curved surface as shown in FIG. 19B, or a small planar grating is formed as a tangent to the curved surface as shown in FIG. 19C. It is necessary to devise such as arranging them along the line.

  Further, the diffraction grating having the 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 size of 6 inches in diameter, a diffraction grating that can be manufactured from this φ6 inch silicon wafer is a square (□: about 10 cm) having a side of about 10 cm. 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.

  From such a situation described above, 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.

JP 2011-206161 A

  By the way, when connecting a some grating | lattice, it is necessary to connect, without damaging a grating | lattice part. In particular, in the case of the above-described X-ray diffraction grating, the grating has a fine structure and is easily damaged. This problem is important. In addition, Patent Document 1 does not mention the connection method of the small lattice, and it is unclear how it is connected.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a lattice capable of reducing breakage of the lattice portion. And this invention is providing the X-ray imaging device containing the grating | lattice unit which used multiple such grating | lattices, and the said grating | lattice or the said grating | lattice unit.

As a result of various studies, the present inventor has found that the above object is achieved by the present invention described below. In other words, the grid according to one aspect of the present invention is provided such that a grid area in which a plurality of members having the same shape are periodically provided and the grid area of the other grid are adjacently connected to each other. Ru and a connection margin become connected allowance regions for.

  Since the lattice having such a configuration can be connected using a connection margin region when a lattice unit is configured by including a plurality of lattices, damage to the lattice portion of the lattice region can be reduced.

Then, the lattice described above, the connection allowance area, the height of the surface, the rather low than the height of the surface of the grating region and not higher than the bottom between the plurality of members in the grating region.

  When the lattice unit configured as described above is formed by connecting a plurality of lattices with an acute angle smaller than 180 °, the surface of the lattice region and the surface of the connecting region are substantially the same height and each surface is Compared with the case where they are flush, the distance between adjacent lattice regions can be shortened.

A lattice according to another embodiment of the present invention is provided outside a lattice region in which a plurality of members having the same shape are periodically provided and outside the lattice region, and the lattice regions of other lattices are adjacent to each other. A connection margin region for connection, the height of the surface of the connection margin region is lower than the height of the surface of the lattice region, and the plurality of members in the lattice region It is characterized by being lower than the bottom surface.

  In the lattice having such a configuration, when a lattice unit is formed by connecting a plurality of lattices with an acute angle smaller than 180 °, the distance between adjacent lattice regions can be further shortened.

  According to another aspect, in the above-described lattice, the connection margin region is provided at least in a periodic direction in the lattice region.

  According to this configuration, a grid is provided in which a marginal area is arranged effectively at a necessary portion.

  Moreover, the lattice unit according to one aspect of the present invention includes any one of the plurality of lattices described above.

The lattice unit having such a configuration can provide a lattice having a wider lattice plane by including a plurality of lattices .

Further, the lattice unit having such a configuration can reduce damage to the lattice portion of the lattice region when the ridge portions of the connection margin regions contact each other in the lattice adjacent to each other. And, from the viewpoint of shortening the distance between adjacent lattice regions, it is preferable that the connecting region has a surface height lower than the surface height of the lattice region, and further, the connecting region, More preferably, the height of the surface is lower than the bottom surface between the plurality of members in the lattice region .

According to another aspect , in the above-described lattice unit, the lattice and the other lattice are in contact with a connection margin region of the other lattice, and the lattice region of the lattice The first normal line and the second normal line of the lattice area of the other grating are connected at an angle of less than 180 ° so as to intersect .

Such a lattice unit can further reduce the distance between adjacent lattice regions .

An X-ray imaging apparatus according to an aspect of the present invention 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, An X-ray imaging device that captures an X-ray image by the Talbot interferometer or the Talbot-Lau interferometer, and the Talbot interferometer or the Talbot-Lau interferometer includes any one of the above-described gratings and any of the above-mentioned Including at least one of the lattice units .

  Since the X-ray imaging apparatus having such a configuration uses any of the above-described gratings as a grating constituting the Talbot interferometer or the Talbot-low interferometer, it is possible to reduce pixel data loss.

The lattice and the lattice unit according to the present invention can reduce breakage of the lattice portion of the lattice region. The X-ray imaging apparatus according to the present invention can reduce pixel data loss.

It is a figure which shows the structure of the lattice unit in 1st Embodiment. It is a cross-sectional perspective view which shows the structure of the grating | lattice in the grating | lattice unit of 1st Embodiment. It is a figure for demonstrating a mode that the grating | lattice in the grating | lattice unit of 1st Embodiment is cut out from a wafer. It is a figure for demonstrating the contact aspect of a grating | lattice and a grating | lattice in the grating | lattice which is not provided with the connection margin area | region. It is a perspective view which shows the structure of the grating | lattice in the grating | lattice unit of 2nd Embodiment. It is a perspective view which shows the structure of the grating | lattice in the grating | lattice unit of 3rd Embodiment. It is a figure for demonstrating a mode that the grating | lattice in the grating | lattice unit of 3rd Embodiment is cut out from a wafer. It is sectional drawing for demonstrating the contact aspect of the grating | lattice in a grating | lattice unit of 3rd Embodiment. It is a perspective view which shows the structure of the grating | lattice in the grating | lattice unit of 6th Embodiment among 4th thru | or 6th Embodiment. It is FIG. (1) which shows the process of forming an insulating layer in the surface of a connection margin area | region. It is FIG. (2) which shows the process of forming an insulating layer in the surface of a connection margin area | region. It is a figure which shows the manufacturing process of the grating | lattice in the grating | lattice unit of 6th Embodiment. It is a figure which shows the mode of the silicon wafer in which the grating | lattice of one Example before cutting process implementation was formed. It is a figure which shows the cutting location in the grating | lattice of one Example. It is a figure which shows the cutting location in the grating | lattice of one comparative example. It is a perspective view which shows the structure of the Talbot interferometer for X-rays in embodiment. It is a top view which shows the structure of the Talbot low interferometer for X-rays in embodiment. It is explanatory drawing which shows the structure of the X-ray imaging device in embodiment. It is a figure for demonstrating generation | occurrence | production of vignetting.

  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 diagram illustrating a configuration of a lattice unit in the first embodiment. FIG. 1A is a front view of the lattice unit, FIG. 1B is a cross-sectional view of a contact portion along line AA shown in FIG. 1A, and FIG. It is a front view. FIG. 2 is a cross-sectional perspective view showing the configuration of the lattice in the lattice unit of the first embodiment. FIG. 2 is a cross-sectional view taken along line BB shown in FIG. FIG. 3 is a diagram for explaining a state in which a lattice in the lattice unit of the first embodiment is cut out from the wafer. FIG. 4 is a diagram for explaining an abutment mode between the lattice and the lattice in a lattice that does not include a connection margin region.

  1 and 2, the lattice unit DGa in the first embodiment includes a plurality of lattices (small lattices, sub-lattices) 1a arranged side by side. In the example shown in FIG. 1A, the lattice unit DGa includes four first to fourth lattices 1a-11, 1a-12, 1a-21, and 1a-22.

  The lattice 1a (1a-11, 1a-12, 1a-21, 1a-22) has a rectangular shape in plan view, and in the example shown in FIG. 1, has a square shape, and as shown in FIG. A lattice region 11a in which a plurality of members having the same shape are periodically provided, and a connection margin region 12a provided outside the lattice region 11a and serving as a connection margin for connection to another lattice 1a are provided.

  These first to fourth lattices 1a-11, 1a-12, 1a-21, 1a-22 are arranged in two rows 2 in two directions independent from each other, in two directions orthogonal to each other in the example shown in FIG. Two adjacent lattices 1a among these first to fourth lattices 1a-11, 1a-12, 1a-21, 1a-22 are arranged in an array in rows (2 × 2), They are arranged so as to abut each other in the connecting area 12a. More specifically, the first grid 1a-11 is arranged in the row direction by the contact margin area 12a-11 of the first grid 1a-11 coming into contact with the connection gap area 12a-12 of the second grid 1a-12. Are connected to the second grid 1a-12, and the connection area 12a-11 of the first grid 1a-11 abuts the connection area 12a-21 of the third grid 1a-21, thereby forming a column. It is connected to the third grid 1a-21 in the direction. Further, the fourth grating 1a-22 is arranged in the column direction by the contact area 12a-22 of the fourth grating 1a-22 coming into contact with the connection area 12a-12 of the second grating 1a-12. 3a in the row direction by the contact area 12a-22 of the fourth lattice 1a-22 being in contact with the connection area 12a-21 of the third lattice 1a-21. It arrange | positions in connection with the grating | lattice 1a-21.

  Further, as shown in FIG. 1B, the first lattice 1a-11 and the second lattice 1a-12 are connected to the lattice regions 11a-11, 11a-12 in the connection margin regions 12a-11, 12a-12. One connecting margin area 12a-11 (12a-12) abuts the other connecting margin area 12a-12 (12a-11) at the ridge portion of the other end facing the one end, and the first lattice 1a- 11 is arranged at a predetermined acute angle of less than 180 ° so that the first normal of the lattice region 11a-11 in 11 and the second normal of the lattice region 11a-12 in the second lattice 1a-12 intersect. Similarly, the 3rd grating | lattice 1a-21 and 4th grating | lattice 1a-22 are the other edge part which opposes one edge part connected to the grating | lattice area | regions 11a-21 and 11a-22 in the connection area | regions 12a-21 and 12a-22. One connecting margin area 12a-21 (12a-22) abuts on the other connecting margin area 12a-22 (12a-21) at the ridge portion of the third grating 1a-21, and the third grating area 11a-21 has a first The three normals and the fourth normal of the grating region 11a-22 in the fourth grating 1a-22 are arranged at an acute angle of a predetermined angle of less than 180 ° so as to intersect.

  The arrangement method of each of the lattices 1a-11, 1a-12, 1a-21, 1a-22 is not particularly limited. For example, the lattices 1a-11, 1a are arranged in the above-described manner by a holding frame (not shown). -12, 1a-21, 1a-22 may be held and arranged, for example, each grid 1a-11, 1a-12, in the above-described manner by a clip (not shown) sandwiching each connection margin region 12a. 1a-21, 1a-22 may be supported and arranged, for example, each grid 1a-11, 1a-12, 1a-21, 1a-22 in the manner described above with an adhesive in each connecting region 12a. May be arranged to be bonded and fixed to each other. Or these arrangement methods may be combined suitably.

  As described above, the first to fourth gratings 1a-11, 1a-12, 1a-21, and 1a-22 are arranged in an array of 2 rows and 2 columns to form a grating unit DGa.

  More specifically, as shown in FIG. 2, the lattice 1a forming the lattice unit DGa includes a lattice region 11a, a connecting region 12a, and a base 13 that supports the lattice region 11a and the connecting region 12a. And. The base 13 is plate-shaped or layered along the DxDy plane when a DxDyDz orthogonal coordinate system is set as shown in FIG. As will be described later, in the lattice region 11a, when the lattice 1a of the first embodiment is formed by the silicon wafer SW, a predetermined thickness H (Dz direction perpendicular to the lattice surface DxDy (method of the lattice surface DxDy) is used. A plurality of silicon portions 111 having a length in the linear direction) and extending linearly in one direction Dx, and a plurality of void portions having the predetermined thickness H and extending linearly in the one direction Dx ( (A gap portion) 112a is formed (a structure or a lattice structure forming the lattice region 11a), and the plurality of silicon portions 111 and the plurality of gap portions 112a are in a direction Dy orthogonal to the one direction Dx. Are alternately arranged in parallel to the DxDz plane having the direction Dy as a normal line. For this reason, the plurality of silicon portions 111 are disposed at predetermined intervals in a direction Dy orthogonal to the one direction Dx. In other words, the plurality of gap portions 112a are disposed at predetermined intervals in a direction Dy orthogonal to the one direction Dx. The predetermined interval (pitch) P is constant in this embodiment. That is, the plurality of gap portions 112a (the plurality of silicon portions 111) are arranged at equal intervals P in the direction Dy orthogonal to the one direction Dx. These silicon portions 111 have a plate shape or a layer shape along the DxDz plane orthogonal to the DxDy plane. The gaps 112a are plate-like or layer-like along the DxDz plane sandwiched between adjacent silicon parts 111.

  The silicon portion 111 and the gap portion 112a are formed so as to have different refractive indexes. In the example shown in FIG. 2, the refractive index of the silicon portion 111 is the refractive index of silicon (Si), and the gap portion 112a is the refractive index of a predetermined gas (for example, air). Therefore, as one aspect, the grating region 11a functions as a diffraction grating, for example, a phase type diffraction grating, by appropriately setting the predetermined interval P according to a predetermined wavelength (for example, the wavelength of X-rays).

  Such a lattice 1a may be manufactured using a substrate of any material, but in the present embodiment, it is manufactured using a silicon wafer SW in which a fine processing technique is relatively established.

  For example, the lattice 1a is formed by periodically forming a plurality of members (a plurality of silicon portions 111 in the present embodiment) having the same shape on a predetermined substrate (a silicon wafer SW in the present embodiment). The lattice region 11a and the connecting region 12a of the substrate are left so as to leave a connecting region 12a to be connected to connect to another lattice 1a outside the lattice region 11a. And a separation step of separating the remaining area except for the substrate.

More specifically, in the lattice region forming step, a resist layer forming step of forming a resist layer on the main surface of the silicon wafer SW, and patterning the resist layer to remove the patterned portion of the resist layer. The silicon wafer SW corresponding to the portion from which the resist layer has been removed is etched by a patterning step and a predetermined etching method (dry etching method or wet etching method) to form a recess having a predetermined depth H corresponding to the gap portion 112a. The lattice region 11a is formed by performing these steps. Therefore, in the present embodiment, the plurality of silicon portions 111 and the base 13 are integrally formed. The etching method in the etching step is preferably a Bosch process because the sidewalls of the recesses can be formed substantially vertically. This Bosch process is an etching method in which sidewall protection and bottom surface etching are alternately performed by alternately repeating a SF ₆ plasma rich state and a C ₄ F ₈ plasma rich state.

  In the separation step, as shown in FIG. 3A, a cutting line is set along the outer periphery of the lattice region 11a so as to leave the connecting region 12a outside the lattice region 11a. As shown in B) and (C), by performing blade dicing with the blade along the cutting line, the remaining region excluding the lattice region 11a and the connecting region 12a of the silicon wafer SW is separated. Therefore, in the present embodiment, the structure of the connection margin region 12a (the structure that forms the connection margin region 12a, the connection margin structure) and the base 13 are integrally formed.

  By performing such a lattice region forming step and a separation step, the lattice 1a shown in FIG. 2 is formed, and the plurality of lattices 1a are arranged as described above, and as shown in FIG. The lattice unit 1a is manufactured.

  As shown in FIG. 1A, the lattice 1a having such a configuration includes a plurality of lattices 1a (in the present embodiment, four first to fourth lattices 1a-11, 1a-12, 1a-21, When the lattice unit DGa is configured by connecting 1a-22), the lattice unit DGa of the present embodiment is connected to FIG. 1B showing the abutting mode between the lattices 1a adjacent to each other in the row direction. As can be seen by comparing FIG. 4 showing the contact mode between the lattices adjacent to each other in the row direction in a lattice not provided with the region 12a, in the present embodiment, the connecting region 12a can be used for connection. Damage to the lattice portion (silicon portion 111) of the lattice region 11a can be reduced.

  In particular, in the present embodiment, the grating unit DGa has a predetermined angle of less than 180 ° between the gratings 1a adjacent to each other in the row direction, as described above, in order to reduce the occurrence of so-called vignetting that occurs at the time of the point wave source. Since they are formed so as to be arranged at an acute angle, the respective lattices 1a adjacent to each other in the row direction are brought into contact with each other at the respective ridge portions of the respective connection margin regions 12a as shown in FIG. Become. For this reason, the contact point (the ridge portion) needs to be stronger than the case where the contact points contact each other over the entire side surfaces of the connection margin regions 12a. In this regard, in the lattice 1a of the present embodiment, the connecting region 12a is larger in thickness in the periodic direction of the lattice region 11a than the thickness (the length in the Dy direction) of the silicon portion 111 that forms the lattice region 11a ( (The length in the Dy direction), the strength is higher than that in the case of a lattice not including the connecting margin region 12a shown in FIG. Therefore, the lattice unit DGa of the present embodiment can further reduce the damage to the lattice portion (silicon portion 111) of the lattice region 11a as compared with the lattice not including the connection margin region 12a shown in FIG. It is advantageous. From such a viewpoint, it is preferable that the connecting margin region 12a is provided at least in the periodic direction in the lattice region 11a.

  In addition, as will be described later, if blade dicing is performed with a blade directly along the outer periphery of the lattice region 11a without leaving the connection region 12a in the separation step, the silicon portion 111 of the lattice region 11a is damaged. End up. However, in the present embodiment, since the blade dicing is performed with the blade along the cutting line that leaves the connection margin region 12a in the separation step, the breakage of the silicon portion 111 in the lattice region 11a can be reduced. As described above, in the present embodiment, it is possible to provide the lattice 1a that can reduce the breakage of the silicon portion 111 in the lattice region 11a even when the cutting process is performed by blade dicing. As a result, the separation step is performed without breaking the periodicity at the end of the lattice region 11a, and the lattice unit 1a is connected by connecting the lattices 1a in which the periodicity at the end of the lattice region 11a is maintained. DGa can be formed. For this reason, as will be described later, when an X-ray imaging apparatus is configured by using a lattice unit DGa connecting a plurality of gratings 1a, such an X-ray imaging apparatus can reduce pixel data loss. it can. Note that if there is little loss of image data, more specifically, if the pixel size of the image sensor is about several pixels (preferably about one or two pixels), the image data is obtained by image processing such as interpolation. It is possible to compensate for the deficiency.

  From the viewpoint of reducing the damage of the silicon portion 111 in the lattice region 11a, the width of the connection region 12a in the periodic direction of the lattice region 11a is several times the pitch P of the lattice region 11a, for example, 3 times or 4 It is preferable that the length is double or 5 times, and it is preferable that the length corresponds to one pixel or two pixels of the image sensor at the maximum.

  Next, another embodiment will be described.

(Second Embodiment)
FIG. 5 is a perspective view showing a configuration of a lattice in the lattice unit of the second embodiment. Each lattice 1a in the lattice unit DGa of the first embodiment has the same height of the surface of the connecting region 12a as the surface height of the lattice region 11a, but each lattice 1b in the lattice unit DGb of the second embodiment. As shown in FIG. 5, the height of the surface of the connecting region 12b is lower than the height of the surface of the lattice region 11a.

  More specifically, the lattice unit DGb of the second embodiment includes a plurality of lattices 1b arranged side by side, like the plurality of lattices 1a constituting the lattice unit DGa of the first embodiment. As shown in FIG. 5, the grid 1b includes a grid area 11a in which a plurality of members having the same shape are periodically provided, and a connection provided on the outside of the grid area 11a to connect to another grid 1b. A connecting margin region 12b is provided. Since the lattice region 11a in the lattice 1b of the second embodiment is the same as the lattice region 11a in the lattice 1a of the first embodiment, the description thereof is omitted.

  The height of the surface of the connection margin region 12b is lower than the height of the surface of the lattice region 11a. In the present embodiment shown in FIG. 5, the height of the surface of the lattice region 11a and the lattice region 11a Is set between the bottom surfaces of the plurality of silicon portions 111 (that is, the bottom surfaces of the gap portions 112a).

  For example, the lattice 1b having such a structure periodically forms a plurality of members (a plurality of silicon portions 111 in the present embodiment) having the same shape on a predetermined substrate (a silicon wafer SW in the present embodiment). A lattice region forming step for forming the lattice region 11a, a digging step for digging down the surface corresponding to the connection region 12b, and a connection margin region 12a that serves as a connection margin for connecting to another lattice 1a outside the lattice region 11a. And a separation step of separating the remaining regions of the substrate except the lattice region 11a and the connecting region 12a.

  More specifically, the lattice region forming step includes a resist layer forming step, a patterning step, and an etching step, similar to the lattice region forming step of the first embodiment, and the lattice region 11a is performed by these steps. Is formed. In the present embodiment, a gray-tone mask is used in the resist layer forming process, and a portion where there is no resist layer by the patterning process (a region for forming the gap portion 112a), a portion where there is a resist layer having a normal thickness ( The resist layer is patterned in a region where the silicon portion 111 is formed) and a portion where the resist layer is thinner than the normal thickness (a region which becomes the connecting region 12b), and a recess corresponding to the gap portion 112a is formed. In the etching step to be formed, the surface corresponding to the connection margin region 12b is dug down. In the gray tone mask method, when etching is started, in a portion where the resist layer is present, first, the etching of the resist layer is started, and after the etching of the resist layer is finished, the etching of the silicon wafer SW is started. The depth of the etched silicon wafer SW varies depending on the presence or absence of the resist layer and the difference in thickness of the resist layer. As described above, in the present embodiment, the etching process is also used as a digging process. By this etching process, a concave portion corresponding to the gap portion 112a is formed, and a surface corresponding to the connection margin region 12b is dug down.

  By performing these steps, the lattice region 11a is formed in the silicon wafer SW, and the concave groove portion surrounding the outer periphery of the lattice region 11a is formed as a portion that becomes the connecting region 12b.

  In the separation step, a blade is applied so as to enter the concave groove portion to be the connection margin region 12b so as to leave the connection margin region 12b outside the lattice region 11a, and the blade is moved along the concave groove portion with this blade. By performing the dicing, the remaining regions of the silicon wafer SW excluding the lattice region 11a and the connecting region 12b are separated. The width of the concave groove portion serving as the connecting margin region 12b is preferably wider than the width of the blade, but may be equal to or less than the width of the blade.

  By performing such a lattice region forming step, a digging step, and a separation step, the lattice 1b shown in FIG. 5 is formed, and a plurality of lattices 1a in the lattice unit 1a of the first embodiment are formed. By arranging the grating 1b, the grating unit DGb of the second embodiment is manufactured.

  The grid 1b having such a configuration also provides the same operational effects as the grid 1a of the first embodiment.

  In the second embodiment, the grating unit DGb is arranged so that each grating 1b adjacent to each other in the row direction has an acute angle of less than 180 ° in order to reduce the occurrence of so-called vignetting that occurs when the point wave source is used. Thus, when formed, the surface of the connecting area 12b is dug down, so that the surface of the connecting area 12a and the surface of the connecting area 12a are substantially the same height as the lattice unit DGa of the first embodiment. Now, compared with the case where each surface is flush, the distance between the adjacent lattice regions 11a can be shortened. Also from such a viewpoint, it is preferable that the connection margin region 12a is provided at least in the periodic direction in the lattice region 11a.

  In the second embodiment, in the separation step, the blade is applied so as to enter the concave groove portion to be the connecting margin region 12b, and blade dicing is performed along the concave groove portion, so that the blade is silicon in the lattice region 11a. Contact with the portion 111 can be reduced, and breakage of the silicon portion 111 can be reduced. As a result, the lattice unit DGa can be formed by connecting the lattice 1b in which the periodicity at the end of the lattice region 11a is maintained. For this reason, the X-ray imaging apparatus using this lattice unit DGb can reduce pixel data loss.

  Next, another embodiment will be described.

(Third embodiment)
FIG. 6 is a perspective view showing a configuration of a lattice in the lattice unit of the third embodiment. FIG. 7 is a diagram for explaining a state in which a lattice in the lattice unit of the third embodiment is cut out from the wafer. FIG. 8 is a cross-sectional view for explaining a contact mode between the lattice and the lattice in the lattice unit of the third embodiment.

  Each lattice 1a in the lattice unit DGa of the first embodiment has the same height of the surface of the connecting region 12a as the surface height of the lattice region 11a, but each lattice 1c in the lattice unit DGc of the third embodiment. As in the case of each lattice 1b in the lattice unit DGb of the second embodiment, the height of the surface of the connecting region 12c is lower than the height of the surface of the lattice region 11a, and as shown in FIG. Furthermore, the height of the surface of the connection margin region 12c is lower than the bottom surface between the plurality of members in the lattice region 11a (in this embodiment, the bottom surface between the silicon portions 111, that is, the bottom surface of the gap portion 112a). It is.

  More specifically, the lattice unit DGc of the third embodiment includes a plurality of lattices 1c arranged side by side, like the plurality of lattices 1a constituting the lattice unit DGa of the first embodiment. As shown in FIG. 6, the grid 1 c includes a grid area 11 a in which a plurality of members having the same shape are periodically provided, and a connection provided on the outside of the grid area 11 a for connecting to another grid 1 c. A connecting margin area 12c is provided. Since the lattice region 11a in the lattice 1c of the second embodiment is the same as the lattice region 11a in the lattice 1a of the first embodiment, the description thereof is omitted.

  The height of the surface of the connection margin region 12c is made lower than the bottom surface between the plurality of members in the lattice region 11a (in this embodiment, the bottom surface between the silicon portions 111, that is, the bottom surface of the gap portion 112a). Yes.

  For example, the lattice 1c having such a structure periodically forms a plurality of members (a plurality of silicon portions 111 in the present embodiment) having the same shape on a predetermined substrate (a silicon wafer SW in the present embodiment). The lattice region forming step for forming the lattice region 11a, the digging step for digging the surface corresponding to the connecting region 12c, and the connecting margin region 12a that becomes the connecting margin for connecting to another lattice 1a outside the lattice region 11a. And a separation step of separating the remaining regions of the substrate except the lattice region 11a and the connecting region 12a.

  More specifically, the lattice region forming step includes a resist layer forming step, a patterning step, and an etching step, similar to the lattice region forming step of the first embodiment, and the lattice region 11a is performed by these steps. Is formed. In the present embodiment, the surface corresponding to the connection margin region 12c is dug down in the etching step for forming the recess corresponding to the gap portion 112a. That is, this etching process is also used as a digging process, and by this etching process, a concave portion corresponding to the gap portion 112a is formed, and a surface corresponding to the connecting region 12c is dug down by utilizing a so-called microloading effect. It is done. The microloading effect is a phenomenon in the etching method in which the etching rate is reduced as the pattern width is reduced. Therefore, when the width of the concave groove portion that becomes the connection margin region 12c is set wider than the width of the concave portion corresponding to the gap portion 112a, the concave groove portion that becomes the connection margin region 12c corresponds to the gap portion 112a. Etching is deeper than the recess. Similar to the second embodiment, a similar shape can be formed by a processing method using a gray tone mask.

  By performing these steps, a lattice region 11a is formed in the silicon wafer SW, and a concave groove portion surrounding the outer periphery of the lattice region 11a is formed as a portion that becomes a connecting region 12c.

  Then, in the separation step, as shown in FIG. 7A, a blade is applied so as to enter the concave groove portion to be the connecting margin region 12c so as to leave the connecting margin region 12c outside the lattice region 11a. As shown in FIG. 7B, by performing blade dicing along the concave groove with this blade, the remaining region of the silicon wafer SW excluding the lattice region 11a and the connection margin region 12c is separated. The width of the concave groove portion to be the connection margin region 12c is preferably wider than the width of the blade, but may be equal to or smaller than the width of the blade.

  By performing such a lattice region forming process, a digging process, and a separating process, a lattice 1c shown in FIG. 6 is formed, and a plurality of lattices 1a in the lattice unit 1a of the first embodiment are formed. By arranging the grating 1c, the grating unit DGc of the third embodiment is manufactured.

  The grid 1c having such a configuration also provides the same operational effects as the grid 1a of the first embodiment.

  In the third embodiment, in order to reduce the occurrence of so-called vignetting that occurs at the time of the point wave source, the grating units DGc are arranged at a predetermined acute angle of less than 180 ° with each grating 1c adjacent to each other in the row direction. Thus, when formed, since the surface of the connecting margin region 12c is dug down, as can be seen by comparing FIG. 1B and FIG. 8, like the lattice unit DGa of the first embodiment, Compared to the case where the surface of the lattice region 11a and the surface of the connecting region 12a are substantially the same height and each surface is flush, the width of the connecting region 11 is the same in the first embodiment and the second embodiment. Even in such a case, the distance between the adjacent lattice regions 11a can be shortened. Further, in the third embodiment, the height of the surface of the connecting margin region 12c is lower than the bottom surface between the plurality of members in the lattice region 11a (the bottom surface of the gap portion 112a), so the lattice unit DGb of the second embodiment Even in comparison, the distance between the adjacent lattice regions 11a can be made shorter. Also from such a viewpoint, it is preferable that the connection margin region 12a is provided at least in the periodic direction in the lattice region 11a.

  Further, in the third embodiment, in the separation step, the blade is applied so as to enter the concave groove portion that becomes the connecting margin region 12c, and blade dicing is performed along the concave groove portion. Can be cut, and it is possible to reduce or prevent the blade from coming into contact with the silicon portion 111 in the lattice region 11a, and to further reduce the breakage of the silicon portion 111. As a result, the lattice unit DGc can be formed by connecting the lattice 1c in which the periodicity at the end of the lattice region 11a is maintained. For this reason, the X-ray imaging apparatus using this lattice unit DGc can further reduce pixel data loss.

  In the above description, blade dicing is used in the separation step, but the present invention is not limited to this, and other separation means may be used. For example, a laser ablation method in which a solid surface is etched with a laser beam and cut from the outside, or a stealth dicing method in which a laser beam is focused so as to be condensed inside the wafer may be used.

  Here, in each of the lattices 1a, 1b, and 1c of the first to third embodiments, the lattice portion of the lattice region when the lattice unit DG is configured by connecting the plurality of lattices 1 (breakage of the silicon portion 111 will be described). To do.

  When the connection margin 12a in the lattice 1a of the first embodiment and the connection margin 12b in the lattice 1b of the second embodiment are compared (see FIGS. 2 and 5), the width (length in the Dy direction) is the same. The height (Dz direction) is different, and the connecting margin 12b of the second embodiment is lower than the lattice 1a of the first embodiment and closer to the base 13. For this reason, the connection margin 12b in the lattice 1b of the second embodiment has higher strength than the connection margin 12a in the lattice 1a of the first embodiment. Therefore, when the grid unit DG is configured by connecting a plurality of grids 1, the configuration of the second embodiment can be connected using the connection margin region 12b having higher strength than the configuration of the first embodiment. Therefore, damage to the lattice portion (silicon portion 111) of the lattice region 11b can be reduced as compared with the first embodiment.

  Further, when the connection margin 12b in the grid 1b of the second embodiment and the connection margin 12c in the grid 1c of the third embodiment are compared (see FIGS. 5 and 6), the connection margin 12b of the second embodiment has a lattice region. While the silicon portion 111 of 11b partially overlaps, the connection margin 12c of the third embodiment has no portion overlapping the silicon portion 111 of the lattice region 11c and is integrated with the base 13. For this reason, the connection margin 12c in the lattice 1c of the third embodiment has higher strength than the connection margin 12b in the lattice 1b of the second embodiment. Therefore, when the grid unit DG is configured by connecting a plurality of grids 1, the configuration of the third embodiment can be connected using the connection margin region 12c having higher strength than the configuration of the second embodiment. Therefore, damage to the lattice portion (silicon portion 111) of the lattice region 11c can be reduced as compared with the second embodiment.

  Next, another embodiment will be described.

(Fourth to sixth embodiments)
FIG. 9 is a perspective view showing a configuration of a lattice in the lattice unit of the sixth embodiment among the fourth to sixth embodiments. 10 and 11 are views showing a process of forming an insulating layer on the surface of the connection margin region. FIG. 12 is a diagram illustrating a grating manufacturing process in the grating unit of the sixth embodiment. 10 and 11 show the lattice region 11b and the connection margin region 12f of the silicon wafer SW, and the remaining portions are not shown.

  The lattice regions 11a in the lattices 1a, 1b, and 1c of the lattice units DGa, DGb, and DGc of the first to third embodiments have gaps between the silicon portions 111 adjacent to each other. The lattice region 11b in each of the lattices 1d, 1e, and 1f of the lattice units DGd, DGe, and DGf is such that a portion between adjacent silicon portions 111 is filled with a solid material. Thus, by filling the portion between the silicon portions 111 adjacent to each other (a three-dimensional region corresponding to the void portion 112a in the lattice region 11a of the first to third embodiments) with a solid material (preferably metal), the silicon portion 111 is filled. And the phase difference between adjacent silicon portions can be made larger, and the predetermined thickness H in the grating region 11b can be made thinner. Further, by increasing the predetermined thickness H and filling the three-dimensional region between adjacent silicon portions 111 with a solid material, the amount of absorption in the three-dimensional region is increased, and each lattice acting as an absorption lattice It is also possible to manufacture 1d, 1e, and 1f.

  More specifically, the lattice units DGd, DGe, DGf of the fourth to sixth embodiments are respectively a plurality of lattices 1a, 1b, constituting the lattice units DGa, DGb, DGc of the first to third embodiments. Similar to 1c, a plurality of grids 1d, 1e, and 1f arranged side by side are provided.

  The lattice 1d of the fourth embodiment is provided with a lattice region 11b in which a plurality of members having the same shape are periodically provided, and a connection margin provided on the outside of the lattice region 11b to connect to another lattice 1d. And a connecting area 12d. The connecting margin region 12d in the lattice 1d of the fourth embodiment is connected to the connecting margin region 12a in the lattice 1a of the first embodiment, except that a first insulating layer having electrical insulation characteristics is formed on the surface thereof. Since this is the same, the description thereof is omitted.

  The grid 1e according to the fifth embodiment includes the grid region 11b and a connection margin region 12e that is provided outside the grid region 11b and serves as a connection margin for connecting to another grid 1e. The connection margin region 12e in the lattice 1e of the fifth embodiment is the same as the connection margin region 12b in the lattice 1b of the second embodiment except that the first insulating layer is formed on the surface thereof. Description is omitted.

  The lattice 1f of the sixth embodiment includes the lattice region 11b and a connection margin region 12f that is provided outside the lattice region 11b and serves as a connection margin for connection to another lattice 1f. The connection margin region 12f in the lattice 1f of the sixth embodiment is the same as the connection margin region 12c in the lattice 1c of the third embodiment except that the first insulating layer 121f is formed on the surface thereof. The description is omitted.

  That is, the lattices 1d, 1e, and 1f of the fourth to sixth embodiments include the lattice region 11b instead of the lattice region 11a and are connected to the lattices 1a, 1b, and 1c of the first to third embodiments, respectively. The structure is equivalent to the regions 12a, 12b, and 12c, and includes connection margin regions 12d, 12e, and 12f having a first insulating layer formed on the surface. Accordingly, the configurations of the gratings 1d, 1e, and 1f of the fourth to sixth embodiments can be understood by referring to FIGS. 2, 5, and 6, respectively. The illustration of each configuration of the grids 1d and 1e is omitted, and here, the configuration of the grid 1f of the sixth embodiment is shown in FIG.

  In the lattice regions 11b of the lattices 1d, 1e, and 1f of the fourth to sixth embodiments, as will be described later, when the lattices 1d, 1e, and 1f of the fourth to sixth embodiments are formed by the silicon wafer SW. Is a plurality of silicon portions 111 having a predetermined thickness H (length in the Dz direction perpendicular to the lattice plane DxDy (the normal direction of the lattice plane DxDy)) and extending linearly in one direction Dx; A structure (lattice structure) having a plurality of metal portions 112b having a thickness H and extending linearly in the one direction Dx is formed. The plurality of silicon portions 111 and the plurality of metal portions 112b , And alternately in a direction Dy orthogonal to the one direction Dx, in parallel with a DxDz plane having the direction Dy as a normal line. For this reason, the plurality of metal portions 112b are disposed at predetermined intervals in a direction Dy orthogonal to the one direction Dx. The predetermined interval (pitch) P is constant in this embodiment. That is, the plurality of metal portions 112b (the plurality of silicon portions 111) are arranged at equal intervals P in the direction Dy orthogonal to the one direction Dx. The silicon portion 111 has a plate shape or a layer shape along the DxDz plane orthogonal to the DxDy plane. The metal portion 112b has a plate shape or a layer shape along the DxDz plane sandwiched between the silicon portions 111 adjacent to each other.

A plurality of second insulating layers 113 having electrical insulation characteristics are further provided between the plurality of silicon portions 111 and the plurality of metal portions 112b, respectively. That is, the second insulating layer 113 is formed on both side surfaces of the silicon portion 111. In other words, the second insulating layer 113 is formed on both side surfaces of the metal portion 112b. The second insulating layer 113 functions to electrically insulate the silicon portion 111 and the metal portion 112b, and is formed of, for example, an oxide film. The oxide film is, for example, a silicon oxide film (SiO ₂ film, silicon oxide film) or an alumina film (Al ₂ O ₃ film, aluminum oxide film). On the other hand, the second insulating layer 113 as described above is not formed on each bottom surface of the plurality of metal portions 112b, the base 13 faces, and the base 13 and the bottom surface of the metal portion 12b are electrically connected. It is in a state where it is possible to conduct.

  Furthermore, it is preferable that a third insulating layer 114 is further provided on each of the upper surfaces (top portions) of the plurality of silicon portions 111. The third insulating layer 114 functions to electrically insulate the silicon portion 111 in an electroforming method to be described later. The third insulating layer 114 is formed by, for example, a photosensitive resin layer (photoresist film) or an oxide film.

  The silicon base 13, the plurality of silicon portions 111, the first insulating layer 121, the plurality of second and third insulating layers 113 and 114 function to transmit X-rays, and the plurality of metal portions 112b are It functions to absorb X-rays or to add a phase difference to the silicon portion 111. For this reason, as one aspect, the grating 11b functions as a diffraction grating by appropriately setting the predetermined interval P according to the wavelength of X-rays. As the metal of the metal portion 112b, a metal that suitably absorbs X-rays or has a phase difference is selected. For example, a metal having a relatively heavy atomic weight or a noble metal, more specifically, for example, gold (Au) or platinum. (Platinum, Pt), rhodium (Rh), ruthenium (Ru), iridium (Ir) and the like. Further, the metal portion 112b has an appropriate thickness H so that, for example, X-rays can be sufficiently absorbed or phase-difference can be provided according to specifications. As a result, in the case of the absorption type grating, the ratio of the thickness H to the width W in the metal portion 112b (aspect ratio = thickness / width) is, for example, a high aspect ratio of 5 or more. The width W of the metal portion 112b is the length of the metal portion 112b in the direction (width direction) Dy orthogonal to the one direction (long direction) Dx, and the thickness H of the metal portion 112b is equal to the one direction Dx. This is the length of the metal portion 112b in the normal direction (depth direction) Dz of the plane DxDy constituted by the direction Dy perpendicular to this.

  The lattices 1d, 1e, and 1f of the fourth to sixth embodiments having such a lattice region 11b may be manufactured using a substrate of any material, but in this embodiment, the microfabrication technology is relatively Manufactured using an established silicon wafer SW.

  For example, the lattices 1d, 1e, and 1f of the fourth to sixth embodiments are formed on a predetermined substrate (silicon wafer SW in the present embodiment) on a plurality of members having the same shape (in this embodiment, the plurality of silicon portions 111 or A lattice region forming step for forming the lattice region 11b by periodically forming the metal portion 112b), and a connection for connecting to the other lattices 1d, 1e, and 1f outside the lattice region 11b. In order to leave the regions 12d, 12e, and 12f, the substrate is manufactured by performing a separation step of separating the remaining regions other than the lattice region 11b and the connecting regions 12d, 12e, and 12f of the substrate. And in 5th and 6th embodiment, the digging process which digs up the surface of the connection margin area | regions 12e and 12f is further implemented before the said cutting process.

  More specifically, in the lattice region forming step, a resist layer forming step of forming a resist layer on the main surface of the silicon wafer SW, and patterning the resist layer to remove the patterned portion of the resist layer. A patterning step, an etching step of etching the silicon wafer SW corresponding to a portion from which the resist layer has been removed by a predetermined etching method (dry etching method or wet etching method) to form a recess having a predetermined depth, and at least An insulating layer forming step A for forming an insulating layer on the inner surface of the recess in the silicon wafer SW, a removing step for removing the portion of the insulating layer formed at the bottom of the recess, and connecting regions 12d and 12e. , 12f to form an insulating layer on the surface of 12f, and by electroforming, The recess by applying a voltage to Rikon'weha produced by the steps electroforming filled with metal. Note that the resist layer formed by the resist layer forming step may be formed to a thickness that remains even after each step, and may be the third insulating layer 114.

  In the lattices 1e and 1f according to the fifth and sixth embodiments, as described in the second and third embodiments, the surface corresponding to the connecting region 12b is formed in the etching step for forming the recess corresponding to the gap portion 112a. Is dug down.

  Further, the second insulating layer 113 is formed by performing the A-th insulating layer forming step. Note that the third insulating layer 114 may be formed by performing this A-th insulating layer forming step, or a step of separately forming the third insulating layer 114 may be provided.

  Further, the first insulating layer 121 (first insulating layer 121f in the sixth embodiment shown in FIG. 9) is formed by performing the B-th insulating layer forming step. In the B-th insulating layer forming step, for example, the first insulating layer is formed by a vapor deposition method by tilting the silicon wafer SW so that the vapor deposition material flying from the vapor deposition source can be received from two predetermined forward and reverse directions. Is done by.

  More specifically, in the vapor deposition method, as shown in FIG. 10A, a substance (deposition source) to be deposited as the first insulating layer 121 in a vacuum chamber (vacuum deposition tank) of a vacuum deposition apparatus, The silicon wafer SW is disposed so as to face each other, and when the deposition source is heated, the film-forming substance (deposition substance) evaporates into a gaseous state and flies. When this vapor deposition material reaches the surfaces of the connecting areas 12d, 12e, and 12f, the vapor deposition material is deposited and deposited on this portion. In order to form the first insulating layer 121 having a higher density and higher strength, an ion beam assisted deposition (Ion-beam Assisted Deposition) is performed in which an ion gun irradiates the substrate with gas ions of about several hundred eV during vacuum deposition. IAD) may be used.

Here, since the vacuum deposition method is usually performed under a low pressure of about 10 ⁻² to 10 ⁻⁴ Pa, the average free path of the deposited material is as long as about several tens of cm to several tens of meters and almost collides. Therefore, the vapor deposition material evaporated from the vapor deposition source has a very good directivity. For this reason, since the directivity of the vapor deposition material is extremely high in the vacuum vapor deposition method, the first insulating layer 121 is formed on the surface of the connection regions 12d, 12e, and 12f without forming an insulating layer on the bottom surface of the recess. In order to form a film, first, as shown in FIG. 10B, the vapor deposition material flying from the vapor deposition source is formed in the plane formed by the thickness direction of the silicon portion 111 and the normal direction of the side surface of the silicon portion 111 ( The normal direction of the silicon wafer SW so as to be received from a direction having a predetermined angle + θ (with the normal direction of the opening surface of the recess being 0 degree) with respect to the opening surface of the recess in the DyDz plane) When the deposition source is disposed on the first insulating layer 121, the silicon wafer SW is tilted clockwise by a predetermined angle θ, and the first insulating layer 121 is formed slightly obliquely by the deposition method. Next, the silicon wafer SW is tilted in the opposite direction and the vapor deposition method is performed in the same manner to form the first insulating layer 121. That is, as shown in FIG. 10C, the deposition material flying from the deposition source is received from a direction having a predetermined angle −θ with respect to the opening surface of the recess in the DyDz plane. When the vapor deposition source is arranged in the normal direction of the wafer SW, the first insulating layer is formed by the vapor deposition method with the silicon wafer SW inclined at a predetermined angle θ counterclockwise.

  The first insulating layer 121 can be formed on the surfaces of the connection regions 12d, 12e, and 12f without forming an insulating layer on the bottom surface of the recess by such a vapor deposition method. For example, in the case of the lattice 1f of the sixth embodiment, the resist layer forming step, the patterning step, the etching step, the first insulating layer forming step, and the removing step are formed, for example, in FIG. As shown in FIG. 11B, the silicon wafer SW shown in FIG. 10 is subjected to the B-th insulating layer forming step of the vapor deposition method, whereby the first insulating layer 121f is formed on the surface of the connecting margin region 12f. .

  Further, in such a vapor deposition method shown in FIG. 10, an insulating layer is also formed on a portion corresponding to the top of the silicon portion 111 (top surface and ridge), and the third insulating layer 114 is also formed. In this manner, the first insulating layer can be formed at a low cost by using a vapor deposition method that can be performed with less expensive equipment.

  Then, the recess is filled with metal by the electroforming process. Here, since the first insulating layer 121 is formed by the B-th insulating layer forming step, metal is not deposited in the connection regions 12d, 12e, and 12f, but only in the recesses. Metal is buried.

  In the separation step, in the case of the fourth embodiment, as in the case of the first embodiment shown in FIG. 3, the outer periphery of the lattice region 11b is left so as to leave the connecting region 12d outside the lattice region 11b. A cutting line is set along the cutting line, and blade dicing is performed along the cutting line, so that the remaining area of the silicon wafer SW excluding the lattice area 11b and the connecting area 12d is cut off.

  On the other hand, in the case of the fifth and sixth embodiments, in the separation step, the recesses that become the connection regions 12e and 12f are left in the separation step so as to leave the connection regions 12e and 12fc outside the lattice region 11b. A blade is applied so as to enter the groove portion, and by performing blade dicing along the concave groove portion with this blade, the remaining regions other than the lattice region 11b and the connecting regions 12e and 12f of the silicon wafer SW are cut off. . FIG. 12 shows a separation process when the grating 1 of the sixth embodiment is manufactured. The width of the concave groove portion to be the connection margin regions 12e and 12f is preferably wider than the width of the blade, but may be equal to or less than the width of the blade.

  By performing each of the above steps, the gratings 1d, 1e, and 1f of the fourth to sixth embodiments are formed, and a plurality of gratings are provided in the same manner as the plurality of gratings 1a in the grating unit 1a of the first embodiment. By arranging 1d, 1e, and 1f, the lattice units DGd, DGe, and DGf of the fourth to sixth embodiments are manufactured.

  When the lattice unit DGd is configured by connecting a plurality of lattices 1d, the lattice 1d of the fourth embodiment having such a configuration has the same effects as the lattice 1a of the first embodiment. Further, the lattice 1e of the fifth embodiment having such a configuration has the same effects as the lattice 1b of the second embodiment when the lattice unit DGe is configured by connecting a plurality of lattices 1e. And the grating | lattice 1f of 6th Embodiment of such a structure has the same effect as the grating | lattice 1c of 3rd Embodiment, when the grating | lattice unit DGf is comprised by connecting the some grating | lattice 1f.

  In the lattices 1e and 1f according to the fifth and sixth embodiments, since the concave portions that become the connecting regions 12e and 12f are not filled with a solid material (for example, metal), a separation process is performed by blade dicing. Even in this case, damage to the silicon portion 111 in the lattice region 11b can be reduced.

  In addition, although the grating | lattices 1a-1f of the above-mentioned 1st thru | or 6th embodiment and the grating | lattice units DGa-DGf using this made the mutually adjacent grating | lattices 1a-1f contact, it does not necessarily need to contact | abut. There may be a gap that allows pixel interpolation.

  Moreover, although the grating | lattices 1a-1f of the above-mentioned 1st thru | or 6th embodiment and the grating | lattice units DGa-DGf using this were 1-dimensional periodic structures, it is not limited to this. The gratings 1a to 1f and the grating units DGa to DGf may be, for example, a grating having a two-dimensional periodic structure. For example, a lattice DG having a two-dimensional periodic structure is configured by arranging dots serving as lattices at equal intervals with a predetermined interval in two linearly independent directions. Such a lattice having a two-dimensional periodic structure has holes in a plane with a high aspect ratio such as a columnar shape or a polygonal column shape in a two-dimensional cycle, and the holes are filled with metal, as described above. A columnar body having a high aspect ratio can be formed by standing upright in a two-dimensional cycle and filling the periphery with metal in the same manner as described above.

  Next, examples and comparative examples will be described.

(Examples and Comparative Examples)
FIG. 13 is a diagram showing a state of the silicon wafer on which the lattice of one example before the separation step is formed. FIG. 13A is a front view, and FIG. 13B is a cross-sectional view of the vicinity of the concave groove. FIG. 14 is a diagram illustrating a cut portion in the lattice of one embodiment. 14A shows a cutting location along the longitudinal direction of the silicon portion 111, FIG. 14B shows a cutting location along the direction orthogonal to the longitudinal direction of the silicon portion 111, and FIG. (C) is a cross-sectional view of the vicinity of the groove portion. FIG. 15 is a diagram illustrating a cut portion in a lattice of one comparative example. FIG. 15A shows a cutting location along the longitudinal direction of the silicon portion 111, and FIG. 15B shows a cutting location along the direction orthogonal to the longitudinal direction of the silicon portion 111.

  As an example, here, the case of the grating 1c of the third embodiment will be described. In this embodiment, as shown in FIG. 13, a lattice region 11a is formed on a silicon wafer SW having a diameter of 6 inches with a pitch of 4.5 μm and a thickness of 18 μm (depth of 18 μm), and the entire outer periphery of the lattice region 11a is formed. The groove portion SD that becomes the connecting region 12c is formed with a width of 1 mm and a depth of 40 μm, and the silicon wafer SW performs blade dicing while leaving 15 μm of the width 1 mm of the groove portion SD. The square lattice 1c having a side of 10 cm was cut.

  On the other hand, in the comparative example, the lattice region 11a is formed in a silicon wafer SW having a diameter of 6 inches with a pitch of 4.5 μm and a thickness of 18 μm (depth of 18 μm), without providing the concave groove portion SD serving as a connecting region 12c. Further, the silicon wafer SW was cut by blade dicing along the boundary of the lattice region 11a, and a square lattice having a side of 10 cm was manufactured.

  The cut portions of these examples and comparative examples are shown in FIGS. 14 and 15, respectively. As can be seen from comparison between FIG. 14 and FIG. 15, in the embodiment provided with the connection margin region 12 c, the silicon portion 111 in the lattice region 11 a is not damaged, but in the comparative example not provided with the connection margin region, In both the direction along the longitudinal direction of the portion 111 and the direction orthogonal thereto, the silicon portion 111 is broken in the lattice region 11a.

  Since the lattice 1c of the embodiment includes the connection margin region 12c, even when the lattice unit DGc is formed, the silicon portion 111 can be connected to another lattice 1c while maintaining a state in which the silicon portion 111 is not damaged. Become.

  Therefore, a plurality of such gratings 1c are manufactured, and the manufactured grating 1c is arranged in the same manner as in the arrangement mode of Patent Document 1 so as to follow an arc having a radius of 1.1 m. Produced.

  The grating 1a and the grating unit DGa of the first embodiment were also manufactured. That is, a lattice region 11a is formed on a silicon wafer SW having a diameter of 6 inches with a pitch of 4.5 μm and a thickness of 18 μm (depth of 18 μm). A connecting region 12a having a width of 15 μm is formed along the entire outer periphery of the lattice region 11a. The silicon wafer SW was cut by blade dicing, and a square lattice 1a having a side of 10 cm was manufactured. A plurality of such lattices 1a are manufactured, and the lattice unit DGa is manufactured by arranging the manufactured lattices 1a along an arc having a radius of 1.1 m.

  When the lattice unit DGa and the lattice unit DGc manufactured in this way are compared, in the lattice unit DGa, the distance between the respective lattice regions 11a in the circumferential direction is about 30 μm, whereas in the lattice unit DGc, each distance in the circumferential direction is The distance between the lattice regions 11a was about 17 μm. Thus, by making the surface of the connecting region 12c lower than the surface of the lattice region 11a, more preferably lower than the bottom surface of the gap portion 112a, a plurality of lattices 1 are connected to form a lattice unit DG. In this case, the distance between each lattice region of each lattice can be shortened. As a result, when the X-ray imaging apparatus is configured by using the lattice unit DG that connects the plurality of gratings 1, such an X-ray imaging apparatus can reduce pixel data loss. Note that a pixel size of a flat panel display (FPD) generally used in an X-ray imaging apparatus is about 100 μm to about 200 μm.

(Talbot interferometer and Talbot low interferometer)
The grating 1 (1a to 1f) and the grating unit DG (DGa to DGf) of the above embodiment can be suitably used for an X-ray Talbot interferometer and a Talbot-Lau interferometer as one application example. An X-ray Talbot interferometer and an X-ray Talbot-low interferometer using the grating 1 and the grating unit DG will be described.

  FIG. 16 is a perspective view showing a configuration of an X-ray Talbot interferometer in the embodiment. FIG. 17 is a top view showing a configuration of an X-ray Talbot-Lau interferometer in the embodiment.

  As shown in FIG. 16, 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 102 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 1 or the grating unit DG.

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 102, Z1 is the distance from the first diffraction grating 102 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 200 </ b> A 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 having such a configuration shown in FIG. 16, 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 having a plurality of slits 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 gratings 1d, 1e, and 1f or the grating units DGd, DGe, and DGf manufactured by the manufacturing method in the fourth to sixth embodiments described above. By manufacturing the multi-slit plate 204 by the manufacturing method of the above-described embodiment, X-rays can be transmitted through the slits (the plurality of silicon portions 111) and more reliably blocked by the plurality of metal portions 112b. Therefore, since transmission and non-transmission of X-rays can be more clearly distinguished, the multi-slit plate 204 can more reliably make X-rays emitted from the X-ray source 201 a 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.

  An example 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 is as follows. In these examples, the silicon portion 111 and the metal portion 112b are formed to have the same width, and the metal portion 112b 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 111 has a thickness of 18 μm, and the second diffraction grating 203 has a pitch P of 5. 3 μm, the thickness of the metal portion 112b 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 112b. Is 100 μm.

(X-ray imaging device)
The grating 1 and the grating unit DG 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 the absorption contrast method that obtains an image in which the magnitude of X-ray absorption by the 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 the grating unit DG will be described.

  FIG. 18 is an explanatory diagram illustrating a configuration of the X-ray imaging apparatus according to the embodiment. In FIG. 18, 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, and in this embodiment, an 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 that is approximately Talbot distance L away from the first diffraction grating 303 and that 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 unit DG of the above-described embodiment, for example.

  In the first diffraction grating 303, each of the plurality of gratings constituting the first diffraction grating 303 is an X-ray source so that a normal passing through the center of the light receiving surface passes through a radiation source of the X-ray source 304 as a point light source. 304 is preferably arranged along a virtual cylindrical surface with a virtual line passing through the radiation source as a central axis, and the second diffraction grating 302 includes a plurality of gratings constituting the second diffraction grating 302. Each is a virtual cylindrical surface with the imaginary line passing through the radiation source of the X-ray source 304 as the central axis 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 preferable to arrange along.

  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 an image of moire fringes. 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-ray that has passed through the subject S is out of phase with the X-ray that does 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. Further, 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 second diffraction grating 302 of the present embodiment is the metal grating DG in the above-described embodiment having the high-aspect-ratio metal portion 12b, good moire fringes can be obtained and a highly accurate image of the subject S can be obtained. can get.

  Further, since the silicon wafer SW is dry-etched by the Bosch process in the grating 1 of the grating unit DG, the side surface of the concave portion (side surface of the silicon portion 111) becomes flatter, and the second diffraction grating 302 is formed with high accuracy. Can do. For this reason, better moire fringes can be obtained, and a more accurate image of the subject S can be obtained.

  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 unit DG or the grating 1 in the above-described embodiment. 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.

  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.

DG Grating unit 1 Grating 11 Grating area 12 Connection area 200A Talbot interferometer 200B Talbot-Lau interferometer 300 X-ray imaging device

Claims (6)

A lattice region in which a plurality of members having the same shape are periodically provided;
A connection margin region provided outside the lattice region and serving as a connection margin for connecting the lattice regions of other lattices adjacent to each other;
The connecting margin region has a surface having a surface height lower than a surface height of the lattice region and higher than a bottom surface between the plurality of members in the lattice region. A lattice region in which a plurality of members having the same shape are periodically provided;
A connection margin region provided outside the lattice region and serving as a connection margin for connecting the lattice regions of other lattices adjacent to each other;
The connecting margin region has a surface having a surface height lower than a surface height of the lattice region and lower than a bottom surface between the plurality of members in the lattice region. The lattice according to claim 1 or 2, wherein the connection margin region is provided at least in a periodic direction in the lattice region. A lattice unit comprising the plurality of lattices according to any one of claims 1 to 3. The grid and the other grid are connected so that a connection area of the grid is in contact with a connection area of the other grid, and the first normal of the grid area of the grid and the grid area of the other grid The lattice unit according to claim 4, wherein the lattice units are connected at an angle of less than 180 ° so that the two normals intersect. 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 is at least one of the grating according to any one of claims 1 to 3, the grating unit according to claim 4, and the grating unit according to claim 5. An X-ray imaging apparatus comprising: