JP2007079458A - Method for manufacturing fine three-dimensional structure and x-ray mask used therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a fine three-dimensional structure for easily manufacturing a fine three-dimensional structure having a predetermined form, and to provide an X-ray mask to be used for the method. <P>SOLUTION: An X-ray absorbent 25 is deposited with various thicknesses in a direction of transmitting X-rays, which results in various transmission quantities of X-rays in a resist layer 22 in the projection region of the X-ray absorbent 25 depending on the thickness of the X-ray absorbent 25 in the transmission direction of X-rays, and changes the X-ray dose (X-ray absorption) irradiating the surface of the resist layer 22. Therefore, by removing the exposed portion of the resist layer 22 by development, a fine three-dimensional structure 27 of a predetermined form having a smooth slope without steps corresponding to the dose of X-rays can be obtained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a fine three-dimensional structure and an X-ray mask used therefor.

  In recent years, research on microfabrication techniques for forming extremely fine structures by applying semiconductor integrated circuit manufacturing techniques has become active. In particular, the LIGA process has attracted particular attention in that a fine three-dimensional structure having a high aspect ratio (ratio of depth to opening width) can be manufactured. “LIGA” is an acronym for Lithographie, Galvanoformung, and Abformung in German, meaning lithography, electroforming, and molding (molding), respectively. The LIGA process is a processing technology that uses a synchrotron radiation X-ray as a light source and combines these elemental technologies to enable the production of a high aspect ratio microstructure. The steps of this LIGA process are as follows, for example.

  That is, as shown in FIG. 6A, in the LIGA process, first, a resist layer 52 having a predetermined thickness made of, for example, polymethyl methacrylate (PMMA) is formed on the substrate 51 as an X-ray photosensitive resist. Next, as shown in FIG. 6B, an X-ray mask 54 having an X-ray absorber (heavy metal such as gold) 53 arranged and formed in a predetermined pattern is placed on the resist layer 52, and the X-ray mask 54 The resist layer 52 is irradiated with X-rays. As a result, the pattern of the X-ray absorber 53 of the X-ray mask 54 is transferred to the resist layer 52. That is, in the resist layer 52, the X-ray exposure site indicated by cross-hatching in FIG. 6B is transformed into a state in which the molecular chain of PMMA is cut by X-rays, the molecular weight is reduced, and it can be dissolved by a predetermined developer. Thereafter, development is performed with a predetermined developer to remove the X-ray exposure site of the resist layer 52. The unexposed portion of the resist layer 52 remains as it is because the molecular weight does not change. Then, a resist microstructure 55 (residual resist layer 52) made of PMMA having the same shape as the pattern of the X-ray absorber 53 having a high aspect ratio of, for example, 100 or more as shown in FIG. 6C is formed. The

  Next, as shown in FIG. 6D, electroplating is performed using the resist microstructure 55 as a mold, and a metal is deposited on the removed portion of the resist layer 52 to form a metal microstructure 56 (electrical). Casting). Finally, as shown in FIG. 6E, a three-dimensional metal microstructure made of metal deposited by electroplating by removing the resist microstructure 55 (resist layer 52), which is a resist at an unexposed portion. A body 56 is created. At this stage, the metal microstructure 56 may be made into a product as a micro part. In some cases, the metal microstructure 56 is used to mold a plastic or the like into a product, or the plastic structure is used to produce a secondary metal product. As described above, the LIGA process is an excellent technique capable of processing a three-dimensional structure having a high aspect ratio.

  However, since X-rays are incident on the substrate 51 perpendicularly as described above, there is a major limitation that only material processing in a direction (processing direction) perpendicular to the substrate 51 can be performed. That is, the resist fine structure 55 which is the remaining resist layer 52 has a horizontal cross-sectional area (area of a cross section parallel to the surface of the substrate 51) that is constant over the entire length in the height direction perpendicular to the surface of the substrate 51. It is formed in a cross-sectional shape. This is because the amount of X-ray irradiation with respect to the resist layer 52 on the substrate 51 is approximately 0% at the position where the X-ray absorber 53 of the X-ray mask 54 exists, and approximately 100% at the position where it does not exist.

  Therefore, conventionally, a method has been proposed in which a plurality of X-ray masks having different transmission patterns are prepared, and X-ray exposure is performed a plurality of times while sequentially replacing the X-ray masks. However, this method has the following problems. That is, a plurality of X-ray masks are necessary, which contributes to an increase in manufacturing cost. Further, at the time of multiple exposure, high positioning accuracy with respect to the substrate of these X-ray masks is required, and the manufacturing process becomes complicated. Furthermore, since the fine three-dimensional structure formed using the plurality of X-ray masks described above has stepped steps in the processing direction (depth direction), the smooth inclined surface does not have these steps. It was difficult to apply to the processing of a structure having

  In order to form a smooth inclined surface having no step as described above, for example, as disclosed in Patent Document 1, a circular X-ray absorber or a mask having a through hole is made relative to a resist layer on a substrate. Conventionally, a processing method has been proposed in which X-rays are irradiated to the resist layer through the mask while moving the target. Specifically, the mask is continuously moved in a horizontal plane so as to draw a circle having a radius smaller than the radius of the X-ray absorber and at a constant angular velocity. Thereby, the area | region where X-ray irradiation amount changes continuously between the area | region where X-rays are always interrupted | blocked by the X-ray absorber, and the area | region where X-rays are always irradiated. As a result, the resist layer after development has a truncated cone shape. In this way, the above-described smooth inclined surface having no step is formed.

The same document also discloses the following processing method. That is, two upper and lower X-ray masks are arranged above the substrate. These X-ray masks are a laminate of an X-ray transmission film and an X-ray absorption film. Square holes are formed in the line absorption film, and X-rays can be transmitted through overlapping portions of the holes of the two X-ray masks. Then, the two X-ray masks are linearly moved from the state in which the holes are alternately overlapped in the left-right direction so that the holes of the two X-ray masks coincide with each other, whereby the resist layer has an inverted quadrangular pyramid shape. The fine structure (hole) is formed. Even in this case, the above-described smooth inclined surface having no step is formed.
Japanese Patent No. 3380878

  However, in the conventional method for manufacturing a fine three-dimensional structure, it is necessary to mount a moving mechanism for moving the X-ray mask relative to the substrate in parallel to the processing apparatus, which complicates the processing apparatus. As a result, the equipment cost was also increased. In addition, it is necessary to secure the alignment accuracy between the X-ray mask and the substrate at a high level, and there is a problem that movement control of the X-ray mask becomes complicated.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for manufacturing a fine three-dimensional structure capable of easily producing a fine three-dimensional structure having a predetermined shape, and use the same. It is to provide an X-ray mask.

  According to the first aspect of the present invention, the work is irradiated with X-rays through a mask having an X-ray absorber arranged in a predetermined pattern, and a portion exposed to the X-rays of the work is developed and removed. Is a method for manufacturing a fine three-dimensional structure in which the workpiece is subjected to predetermined processing according to the pattern of the X-ray absorber, the X-ray absorber having a change in thickness in the X-ray transmission direction, Accordingly, the gist of the invention is that the X-ray transmission amount with respect to the projected portion of the X-ray absorber in the workpiece is made different according to the thickness of the X-ray absorber in the X-ray transmission direction.

  The invention described in claim 2 is the method of manufacturing a fine three-dimensional structure according to claim 1, wherein the X-ray absorber includes a main body portion having an equal cross-sectional shape in the X-ray transmission direction and an upper portion of the main body portion. Alternatively, the gist is provided with a head that is formed to project outward at the lower portion and has an unequal cross-sectional shape in the X-ray transmission direction.

  According to a third aspect of the present invention, in the method for manufacturing a fine three-dimensional structure according to the second aspect, the outer surface of the head is formed into a curved surface so as to have an unequal cross-sectional shape in the X-ray transmission direction. This is the gist.

The gist of the invention described in claim 4 is that it is applied to the production of an optical component in the method for producing a fine three-dimensional structure according to any one of claims 1 to 3. .
The invention described in claim 5 is an X-ray mask used for manufacturing a fine three-dimensional structure by processing a workpiece using X-ray irradiation, and an X-ray absorber arranged in a predetermined pattern. The X-ray absorber has a change in the thickness in the X-ray transmission direction, whereby the X-ray transmission amount with respect to the projection site of the X-ray absorber in the workpiece is changed to the thickness in the X-ray transmission direction of the X-ray absorber. The gist is that they are made different depending on the case.

(Function)
According to the first aspect of the present invention, the X-ray absorber is given a change in thickness in the X-ray transmission direction. For this reason, the X-ray transmission amount with respect to the projection part of the X-ray absorber in the workpiece differs depending on the thickness of the X-ray absorber in the X-ray transmission direction, and the X-ray irradiation amount (X-ray absorption amount) exposed on the surface of the workpiece ) Will change. As a result, by removing the exposed portion of the workpiece by development, a fine three-dimensional structure having a predetermined shape having a smooth surface with no step according to the X-ray irradiation dose is obtained.

  For example, as shown in claim 2, the X-ray absorber is formed so as to protrude outwardly at a main body portion having an equal cross-sectional shape in the X-ray transmission direction and at an upper portion or a lower portion of the main body portion. And a head having an unequal cross-sectional shape in the line transmission direction. For this reason, the X-ray transmission intensity at the projection site of the X-ray absorber is weakest at the site corresponding to the main body, and becomes stronger from the center of the head toward the outer periphery. The workpiece is processed into a shape that follows the X-ray transmission intensity. For example, it is possible to obtain a hole or groove having a smooth inclined surface having no step in which the opening area increases toward the surface of the workpiece.

In addition, as shown in claim 3, by forming the outer surface of the head of the X-ray absorber in, for example, a curved shape, the X-ray absorber can have an unequal cross-sectional shape in the X-ray transmission direction. .
And as shown in Claim 4, the manufacturing method of the fine three-dimensional structure as described in any one of Claims 1-3 can also be applied, for example to manufacture of an optical component.

  If the X-ray mask of Claim 5 is used, a change will be given to the thickness in a X-ray transmissive direction of an X-ray absorber. For this reason, the X-ray transmission amount with respect to the projection part of the X-ray absorber in the workpiece varies depending on the thickness of the X-ray absorber in the X-ray transmission direction, and the X-ray irradiation amount exposed on the surface of the workpiece is changed. . As a result, by removing the exposed portion of the workpiece by development, a fine three-dimensional structure having a predetermined shape having a smooth surface with no step according to the X-ray irradiation dose is obtained.

  According to the present invention, a fine three-dimensional structure having a predetermined shape can be easily manufactured by changing the thickness of the X-ray absorber in the X-ray transmission direction.

Hereinafter, an embodiment in which the present invention is embodied in a light guide (light guide) used in a backlight for a transmissive liquid crystal display panel, for example, will be described with reference to FIG.
<Light guide>
As shown in FIG. 1, a backlight 11 that illuminates a transmissive liquid crystal display panel (not shown) from the back includes a light source 12 and a light guide 13. In order to reduce the thickness of the backlight 11, the light guide 13 is formed in a rectangular flat plate using a transparent material such as polymethyl methacrylate (PMMA), and a light source is provided so as to face one side of the light guide 13. 12 is arranged. One surface (upper surface in FIG. 1) of the light guide 13 is a light emitting surface 12a, and a number of protrusions 15 are formed on the light emitting surface 12a by forming a large number of recesses. The recess 14 and the protrusion 15 are each formed in a truncated cone shape having four tapered surfaces 14a (inclined surfaces). The light from the light source 12 is emitted from the entire surface of the light emitting surface 12a of the light guide 13 by being scattered or reflected by the protrusions 15 and the recesses 14 (more precisely, the tapered surfaces 14a thereof) of the light guide 13. The liquid crystal display panel arranged to face the light emitting surface 12a is illuminated from the back surface.

<Method for producing light guide>
Next, a method for manufacturing the light guide configured as described above will be described. In the present embodiment, the light guide 13 is manufactured using a LIGA process. The LIGA process is performed by lithography using synchrotron radiation, creation of a fine structure by electroforming such as nickel or copper, and further by injection molding of plastics or powder using the fine structure as a fine mold. This is a method for creating a simple three-dimensional structure. In the present embodiment, the light guide 13 is manufactured through the steps up to lithography in each step of the LIGA process.

<Resist application>
In manufacturing the light guide 13, first, a resist layer 22 is formed on the substrate 21 as shown in FIG. As the substrate 21, a metal substrate such as copper or a silicon substrate on which a metal such as titanium is deposited is used. Further, as the material of the resist layer 22, a resist material such as polymethyl methacrylate (PMMA) is used. This resist material is appropriately selected according to the product to be manufactured. The thickness of the resist layer 22 is also set as appropriate according to the product to be manufactured.

<Exposure>
Next, as shown in FIG. 2B, an X-ray mask 23 is arranged above the substrate 21, and X-rays 24 from an X-ray light source (not shown) are applied to the resist layer 22 through the X-ray mask 23. Irradiate.

  For example, polyimide is used as the translucent substrate constituting the X-ray mask 23. The X-ray mask 23 includes an X-ray absorber 25 arranged and formed in a predetermined pattern. A heavy metal such as gold is used as the X-ray absorber 25, and the shape of the X-ray absorber 25 is arbitrarily selected according to a desired resist pattern.

  In the present embodiment, the X-ray absorber 25 has a change in thickness in the X-ray transmission direction. In that case, the X-ray transmission amount with respect to the projection site of the X-ray absorber 25 in the resist layer 22 varies depending on the thickness of the X-ray absorber 25 in the X-ray transmission direction. Changes in line absorption).

  The shape of the X-ray absorber 25 is, for example, a bump shape as shown in FIG. That is, as shown in the figure, the X-ray absorber 25 includes a main body 31 and a head 32 formed so as to protrude outwardly from the upper portion of the main body 31. The upper surface is formed in a spherical shape. The main body 31 and the head 32 are each formed in a columnar shape, and each has a circular cross-sectional shape in a direction orthogonal to the X-ray transmission direction (vertical direction in FIG. 2B).

  For this reason, the X-ray transmission intensity at the projection site of the X-ray absorber 25 is weakest at the site corresponding to the main body 31 and becomes stronger from the center of the head 32 toward the outer periphery. In this case, the distribution shape of the X-ray transmission intensity in the projected portion of the X-ray absorber 25 is trapezoidal as shown in FIG. This indicates that, in the projection portion of the X-ray absorber 25 in the resist layer 22, the alteration depth of the portion corresponding to the main body portion 31 is the shallowest and gradually becomes deeper from the center of the head toward the outer peripheral edge. Yes. Therefore, the resist layer 22 is processed (denatured) into a shape (here, a cross-sectional trapezoidal shape) following the X-ray transmission intensity. The altered portion 22a of the resist layer 22 due to the X-rays 24 has an inverted truncated cone shape as shown by cross-hatching in FIG. 2B (only the cross section in the X-ray transmission direction is shown in FIG. 2B).

<Development>
Next, the exposed resist layer 22 is developed with a predetermined developer to remove the altered portion 22a caused by the X-rays 24. Then, as shown in FIG. 2D, a large number of recesses 14 and protrusions 15 are formed in the resist layer 22. In this embodiment, since the altered portion 22a of the resist layer 22 due to the X-rays 24 has an inverted truncated cone shape, the protrusion 15 has a truncated cone shape, and the recess 14 has an inverted truncated cone shape. For this reason, the opening width W (more precisely, the opening area Sw) of the recess 14 becomes larger toward the surface of the resist layer 22. Further, the cross-sectional area of the protrusion 15 parallel to the substrate 21 becomes smaller toward the surface of the resist layer 22. That is, the inner surface of the recess 14 and the outer surface of the protrusion 15 are inclined so as to form a predetermined angle α with respect to the thickness direction of the resist layer 22 (vertical direction in FIG. 2D). Thus, the fine three-dimensional structure 27 of the resist layer 22 is formed.

  Then, the light guide 13 which is the fine three-dimensional structure 27 of the resist layer 22 is created as an optical component by removing the substrate 21. Thus, the manufacture of the light guide 13 is completed. The predetermined angle α differs in required value depending on the size, shape, processing depth, and X-ray wavelength region of the desired resist pattern (that is, the fine three-dimensional structure 26).

<Manufacturing method of X-ray mask>
Next, a method for manufacturing the X-ray mask 23 configured as described above will be described. In the present embodiment, the X-ray absorber 25 is produced by excessive plating of heavy metal such as gold.

  That is, as shown in FIG. 3A, a photoresist 42 having a predetermined film thickness is applied on the substrate 41. Thereafter, a UV mask 43 is disposed above the substrate 41, and the photoresist 42 is irradiated with ultraviolet (UV) 44 from an ultraviolet source (not shown) through the UV mask 43. For example, a large number of circular through holes 45 are formed in the UV mask 43 in a predetermined arrangement pattern, and ultraviolet rays can pass only through the through holes 45. Therefore, the photoresist 42 is exposed only at the portion corresponding to the through hole 45.

  Next, the exposed photoresist 42 is developed with a predetermined developer to remove the altered portion 42 a due to the ultraviolet ray 44. Then, as shown in FIG. 3B, a large number of recesses 46 corresponding to the arrangement pattern of the through holes 45 are formed in the photoresist 42. Next, as shown in FIG. 3C, for example, gold plating is performed to be thicker than the photoresist 42 (so-called overplating). After the deposition height reaches the upper surface of the photoresist 42 and the main body portion 31 is formed, the disk-shaped head portion 32 protrudes to the side so as to be larger than the inner diameter of the recess 46. The plating is deposited on. At this time, the plating process is controlled so that the upper surface of the head 32 is spherical.

  Then, as shown in FIG. 3D, the X-ray absorber 25 is created on the substrate 41 by removing the photoresist 42 with a predetermined stripping solution. That is, the main body part 31 of the X-ray absorber 25 is a part in the recess 46, and the head part 32 is an overplated part. Thereafter, as shown in FIG. 3E, for example, polyimide 47, which is an X-ray translucent base material, is applied on the substrate 41 so that a large number of created X-ray absorbers 25 are embedded. . Finally, if the substrate 41 is removed, the X-ray mask 23 containing a large number of X-ray absorbers 25 is manufactured. Thus, the manufacture of the X-ray mask 23 is completed.

<Effect of embodiment>
Therefore, according to the present embodiment, the following effects can be obtained.
(1) The thickness of the X-ray absorber 25 in the X-ray transmission direction is changed. For this reason, the amount of X-ray transmission with respect to the projection site of the X-ray absorber 25 in the resist layer 22 varies depending on the thickness of the X-ray absorber 25 in the X-ray transmission direction, and X-ray irradiation exposed on the surface of the resist layer 22 The amount (X-ray absorption) is changed. As a result, by removing the exposed portion of the resist layer 22 by development, a fine three-dimensional structure 27 having a predetermined shape having a smooth surface (slope) with no step according to the amount of X-ray irradiation can be obtained.

  (2) Further, it is possible to form a fine three-dimensional structure 27 having a slope by using one X-ray mask 23. For this reason, it is not necessary to mount a moving mechanism for moving the X-ray mask 23 in parallel with the substrate 21 in the processing apparatus, which simplifies the processing apparatus and contributes to a reduction in equipment cost. . Further, since the movement control of the X-ray mask 23 is not required, the processing control can be simplified. Furthermore, the alignment accuracy between the X-ray mask 23 and the substrate 21 can be easily ensured unlike the case where the two are relatively moved. The manufacturing time of the fine three-dimensional structure 27 having a predetermined shape can be greatly shortened. Therefore, according to the present embodiment, the light guide 13 as a fine three-dimensional structure having a predetermined shape (smooth inclined surface) can be easily manufactured. Since the inner surface of the recess 14 and the outer surface of the protrusion 15 are inclined surfaces, the light from the light source 12 incident from the side of the light guide 13 is efficiently scattered or emitted toward the light emitting surface 12a. Reflected.

  (3) The X-ray absorber 25 is formed so as to project outward at the upper or lower portion of the main body 31 and has an equal cross-sectional shape in the X-ray transmission direction, and in the X-ray transmission direction. The head 32 has an unequal cross-sectional shape. For this reason, the X-ray transmission intensity at the projection site of the X-ray absorber 25 is weakest at the site corresponding to the main body 31 and becomes stronger from the center of the head 32 toward the outer periphery. Since the resist layer 22 is processed into a shape following the X-ray transmission intensity, for example, the concave portion 14 having a smooth inclined surface without a step in which the opening width W (opening area) increases toward the surface of the resist layer 22 or The protrusion 15 is obtained.

(4) Further, by forming the outer surface of the head portion 32 of the X-ray absorber 25 in, for example, a curved shape, the X-ray absorber 25 can have an unequal cross-sectional shape in the X-ray transmission direction.
(5) The light guide 13 as an optical component can be easily manufactured using the LIGA process.

  (6) The X-ray absorber 25 is formed by excessively plating the concave portion 46 of the photoresist 42 with, for example, gold having an X-ray absorption function so as to be thicker than the thickness of the photoresist 42. Therefore, the head part 32 can be easily formed on the upper part of the main body part 31.

Second Embodiment
Next, a second embodiment of the present invention will be described. As shown in FIG. 4A, the X-ray absorber 48 of the present embodiment has a change in the thickness in the X-ray transmission direction of the X-ray mask 49 as in the first embodiment. That is, the X-ray absorber 48 is formed in a truncated cone shape having a tapered surface 48a whose diameter decreases as it goes downward in the figure. The amount of X-ray transmission with respect to the projection site of the X-ray absorber 48 in the resist layer 22 varies depending on the thickness of the X-ray absorber 48 in the X-ray transmission direction, thereby causing the amount of X-ray irradiation (X-ray absorption amount) to the resist layer 22. ) Will change. For this reason, the X-ray transmission intensity at the projection site of the X-ray absorber 48 is the weakest in the vicinity of the center of the X-ray absorber 48 and becomes stronger from the vicinity of the center toward the outer periphery.

  In this case, the distribution shape of the X-ray transmission intensity in the projected portion of the X-ray absorber 48 is trapezoidal as shown in FIG. This indicates that, in the projected portion of the X-ray absorber 48 in the resist layer 22, the alteration depth near the center is the shallowest and gradually becomes deeper from the vicinity of the center toward the outer periphery. Therefore, the resist layer 22 is processed (denatured) into a shape (here, a cross-sectional trapezoidal shape) following the X-ray transmission intensity. The altered portion 22a of the resist layer 22 due to the X-rays 24 has an inverted truncated cone shape as shown by cross-hatching in FIG. 4A (only the cross section in the X-ray transmission direction is shown in FIG. 4A). Then, when the resist layer 22 exposed as described above is developed with a predetermined developer and the altered portion 22a due to the X-rays 24 is removed, the resist layer 22 has a large number of recesses 14 as in the first embodiment. And the protrusion 15 (illustration omitted in Fig.4 (a)) is formed.

  Next, a method for manufacturing the X-ray mask 49 configured as described above will be described. That is, as shown in FIG. 5A, a predetermined conductive metal film 50 is formed on a substrate (silicon substrate) 41, and a photoresist 42 having a predetermined film thickness is applied thereon. Thereafter, a UV mask 43 is disposed above the substrate 41 at a predetermined distance, and the photoresist 42 is irradiated with ultraviolet rays (UV) 44 from an ultraviolet ray source (not shown) through the UV mask 43. For example, a large number of circular through holes 45 are formed in the UV mask 43 in a predetermined arrangement pattern, and ultraviolet rays can pass only through the through holes 45.

  Here, since a predetermined separation distance is formed between the UV mask 43 and the photoresist 42, a part of the ultraviolet light advances around the back side of the UV mask 43 without going straight. Then, the diffracted light 44 a that wraps around the back side of the light enters the photoresist 42 so as to slightly spread out of the projected portion of the through hole 45 (that is, the region immediately below the through hole 45 of the UV mask 43). The diffracted light 44a makes a predetermined angle β with respect to the straight light 44b. The photoresist 42 is altered by the diffracted light 44a as well as the ultraviolet straight light 44b transmitted through the UV mask 43, and as shown by cross-hatching in FIG. 5A, the altered portion of the photoresist 42 altered by exposure. The width of 42 a becomes wider toward the surface of the photoresist 42. In the present embodiment, since the through hole 45 is circular, the altered portion 22a of the photoresist 42 has an inverted truncated cone shape.

  Next, the exposed photoresist 42 is developed with a predetermined developer to remove the altered portion 42 a due to the ultraviolet ray 44. Then, as shown in FIG. 5B, a large number of recesses 46 corresponding to the arrangement pattern of the through holes 45 are formed in the photoresist 42. Next, for example, gold plating is performed to the thickness of the photoresist 42. Then, the X-ray absorber 48 is created on the substrate 41 by removing the photoresist 42 with a predetermined stripping solution. Thereafter, as shown in FIG. 4A, for example, polyimide which is an X-ray translucent base material is applied on the substrate 41 so that a large number of the created X-ray absorbers 48 are embedded. Finally, if the substrate 41 and the conductive metal film 50 are removed, an X-ray mask 49 incorporating a large number of X-ray absorbers 25 is manufactured. This completes the manufacture of the X-ray mask 49.

  Therefore, according to the present embodiment, the X-ray absorber 48 has a truncated cone shape having the tapered surface 48a whose diameter decreases as it goes in the X-ray transmission direction. Therefore, a desired angle γ with respect to the vertical direction of the tapered surface 48 a of the X-ray absorber 48 can be obtained by changing the distance between the photoresist 42 and the UV mask 43 in the manufacturing process of the X-ray absorber 48. In other words, the angle γ of the tapered surface 48 a can be controlled by adjusting the distance between the photoresist 42 and the UV mask 43. The angle γ of the tapered surface 48a increases as the spacing distance increases, and the angle γ of the tapered surface 48a decreases as the spacing distance decreases. Therefore, even when the X-ray absorber 48 is formed by plating, it is possible to precisely control the inclination of the tapered surface 48a. The angle γ of the tapered surface 48a affects the taper angle of the altered portion 22a of the resist layer 22 formed using the X-ray mask 49 provided with the X-ray absorber 48, and consequently the angle α of the recess 14 and the protrusion 15. Effect. For this reason, by precisely controlling the inclination angle of the tapered surface 48a, the inclination angle (angle α) of the tapered surface 14a of the recess 14 and the protrusion 15 can be precisely controlled.

<Another embodiment>
In addition, you may implement both the said embodiment as follows.
-In 1st Embodiment, although the head 32 which comprises the X-ray absorber 25 was similarly provided in the upper part of the main-body part 31, you may make it reverse. That is, the head 32 is provided at the lower part of the main body 31. Even in this case, the X-ray transmission amount varies depending on the thickness of the X-ray absorber 25 in the X-ray transmission direction, and the X-ray irradiation amount (X-ray absorption amount) exposed on the surface of the resist layer 22 varies. Brought about.

  In the first and second embodiments, the X-ray absorber 25 may be formed so that the cross-sectional shape in a direction orthogonal to the X-ray transmission direction is, for example, a quadrangle. Moreover, you may make it into square plate shape.

  In the first and second embodiments, the fine three-dimensional structure 27 of the resist layer 22 is a product (light guide 11), but it may be as follows. That is, electroplating is performed using the fine three-dimensional structure 27 of the resist layer 22 as a mold, and a metal is deposited on the removed portion of the resist layer 22 to form a metal fine structure (not shown). Next, by removing the fine three-dimensional structure 27 of the resist layer 22, a three-dimensional metal fine structure made of metal deposited by electroplating is created. The metal microstructure may be a product. Further, such a metal microstructure may be a mold (mold) of plastic or ceramic mold. In this way, it becomes possible to mass-produce highly accurate fine structure parts at low cost. Further, a secondary micromachine product can be manufactured by using the plastic structure thus produced as an electroplating mold.

<Another technical idea>
Next, a technical idea that can be grasped from the embodiment and another embodiment will be added.
In a method for manufacturing an X-ray mask used for manufacturing a fine three-dimensional structure using X-ray irradiation, a predetermined amount of light is applied to a photoresist applied on a substrate by irradiating with ultraviolet rays through an ultraviolet mask. A first step of performing processing, and applying an excessive amount of plating with a metal having an X-ray absorption action to the processed portion of the photoresist so as to be thicker than the film thickness of the photoresist. A second step of forming an absorber; and a third step of covering the X-ray absorber exposed on the substrate with a light-transmitting substrate after removing the photoresist remaining in the second step; The manufacturing method of the X-ray mask provided with.

The front sectional view of the light guide in a 2nd embodiment. (A), (b), (d) is a front sectional view showing the manufacturing process of the light guide of the first embodiment, and (c) is the thickness and X-ray transmission intensity of the X-ray absorber in the X-ray transmission direction. The characteristic view which shows the relationship. (A)-(f) is a front sectional view which shows the manufacturing process of the X-ray mask in 1st Embodiment, respectively. (A) is front sectional drawing which shows the manufacturing process of the light guide of 2nd this embodiment, (b) is a characteristic view which shows the relationship between the thickness in the X-ray transmission direction of an X-ray absorber, and X-ray transmission intensity similarly. (A), (b) is front sectional drawing which shows the manufacturing process of the X-ray mask of 2nd Embodiment. (A)-(e) is sectional drawing of the board | substrate which shows each process of a LIGA process.

Explanation of symbols

13 ... Light guide (optical component), 22 ... Resist layer (work),
23, 49 ... X-ray mask, 24 ... X-ray, 25, 48 ... X-ray absorber, 27 ... Fine three-dimensional structure, 31 ... Main body, 32 ... Head.

Claims (5)

The workpiece is irradiated with X-rays through a mask having an X-ray absorber arranged in a predetermined pattern, and a portion exposed to X-rays of the workpiece is developed and removed to remove the X-ray absorber on the workpiece. A method for producing a fine three-dimensional structure that is subjected to predetermined processing according to a pattern,
The X-ray absorber has a change in the thickness in the X-ray transmission direction, whereby the amount of X-ray transmission with respect to the projection site of the X-ray absorber in the workpiece is determined according to the thickness of the X-ray absorber in the X-ray transmission direction. A method for producing a fine three-dimensional structure which is made different. In the manufacturing method of the fine three-dimensional structure according to claim 1,
The X-ray absorber is formed so as to protrude outward in the X-ray transmission direction, and to have an unequal cross-sectional shape in the X-ray transmission direction. And a method for manufacturing a fine three-dimensional structure. In the manufacturing method of the fine three-dimensional structure according to claim 2,
A method for manufacturing a fine three-dimensional structure in which the outer surface of the head is formed into a curved surface so as to have an unequal cross-sectional shape in the X-ray transmission direction.   The method for manufacturing a fine three-dimensional structure according to any one of claims 1 to 3, wherein the method is applied to manufacture of an optical component. In an X-ray mask used for processing a workpiece using X-ray irradiation to produce a fine three-dimensional structure,
An X-ray absorber is arranged in a predetermined pattern, and the X-ray absorber has a change in thickness in the X-ray transmission direction, thereby reducing the X-ray transmission amount with respect to the projected portion of the X-ray absorber in the workpiece. An X-ray mask that is made different depending on the thickness of the X-ray absorber in the X-ray transmission direction.

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