JP2011170298A - Method for manufacturing spatial light modulator, spatial light modulator, illumination light generating device, and exposure device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing spatial light modulator, which is capable of solving the following problem: a spatial light modulator has difficulty in improving productivity due to a large number of man-hours for assembly because a piezoelectric element, an elastic member, and a micro mirror are individually manufactured from mutually different materials. <P>SOLUTION: The method for manufacturing the spatial light modulator includes: a coupling step for coupling one end of an electromechanical conversion part expanded and contracted by an electric signal to a driving-side substrate; a formation step for forming a deformable stress relief part on a rear face of a surface for supporting a reflection portion which reflects optical in a driven-side substrate for supporting the reflection portion; and an integration step for integrating the driving-side substrate and the driven-side substrate by coupling the other end of the electromechanical conversion part to the stress relief part. In the coupling step, the plurality of electromechanical conversion parts are coupled to the driving-side substrate. In the formation step, the plurality of stress relief parts are formed on the driven-side substrate. Moreover, in the integration step, the plurality of electromechanical conversion parts and stress relief parts may be integrally coupled. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a spatial light modulator, a spatial light modulator, an illumination light generator, and an exposure apparatus.

There is a micromirror device that has a structure in which a micromirror is swung by transmitting a driving force generated by a piezoelectric element through an elastic member, and operates at high speed (see Patent Document 1).
[Prior art documents]
[Patent Literature]
[Patent Document 1] Japanese Patent No. 4335114

  In the manufacture of the spatial light modulator, the piezoelectric element, the elastic member, and the micromirror are individually made of different materials. For this reason, the spatial light modulator has many assembly steps, and it is difficult to improve productivity.

  In order to solve the above problems, as a first aspect of the present invention, there is provided a spatial light modulator manufacturing method, a coupling step of coupling one end of an electromechanical conversion unit that expands and contracts by an electric signal to a drive side substrate, Forming a deformable stress relieving part on the back side of the surface supporting the reflecting part of the driven side substrate that supports the reflecting part that reflects light, and connecting the other end of the electromechanical conversion part to the stress relieving part. Thus, there is provided a manufacturing method including an integration step of integrating the driving side substrate and the driven side substrate.

  As a second aspect of the present invention, a spatial light modulator manufactured by the above manufacturing method is provided. Furthermore, the illumination light generator provided with the said spatial light modulator is provided as 3rd aspect of this invention. Furthermore, as a fourth aspect of the present invention, there is provided an exposure apparatus provided with the illumination light generator.

  The above summary of the present invention does not enumerate all necessary features of the present invention. Further, a sub-combination of these feature groups can be an invention.

1 is a schematic perspective view showing an appearance of a spatial light modulator 100. FIG. 3 is an exploded perspective view of a unit element 200. FIG. 3 is a cross-sectional view of a unit element 200. FIG. 3 is a cross-sectional view of a unit element 200. FIG. FIG. 11 is a cross-sectional view showing the process of manufacturing the spatial light modulator 100. FIG. 11 is a cross-sectional view showing the process of manufacturing the spatial light modulator 100. FIG. 11 is a cross-sectional view showing the process of manufacturing the spatial light modulator 100. FIG. 11 is a cross-sectional view showing the process of manufacturing the spatial light modulator 100. FIG. 11 is a cross-sectional view showing the process of manufacturing the spatial light modulator 100. FIG. 11 is a cross-sectional view showing the process of manufacturing the spatial light modulator 100. 1 is a schematic perspective view showing an appearance of a spatial light modulator 100. FIG. 3 is an exploded perspective view of a unit element 200. FIG. 3 is a cross-sectional view of a unit element 200. FIG. 3 is a cross-sectional view of a unit element 200. FIG. 3 is an exploded perspective view of a unit element 200. FIG. 3 is a cross-sectional view of a unit element 200. FIG. 3 is a cross-sectional view of a unit element 200. FIG. 3 is an exploded perspective view of a unit element 200. FIG. 3 is a cross-sectional view of a unit element 200. FIG. 3 is a cross-sectional view of a unit element 200. FIG. 3 is an exploded perspective view of a unit element 200. FIG. 3 is a cross-sectional view of a unit element 200. FIG. 3 is a cross-sectional view of a unit element 200. FIG. 2 is a schematic diagram of an exposure apparatus 400. FIG. FIG. 5 is a view showing the operation of the spatial light modulator 100 in the exposure apparatus 400.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a schematic perspective view showing the appearance of the spatial light modulator 100. The spatial light modulator 100 includes a substrate 210 and a plurality of unit elements 200 arranged two-dimensionally on the substrate 210. Each of the unit elements 200 includes a drive unit 220 and a reflection surface 232.

  Each of the plurality of reflecting surfaces 232 forming a matrix on the substrate 210 is supported from the substrate via the driving unit 220. The reflecting surfaces 232 each have a size of about several μm to several hundreds of μm and can be individually rocked with respect to the substrate 210. As shown in the figure, when a part of the reflecting portions 230 swing and reflect light while being inclined with respect to the substrate 210, the illuminance distribution of the reflected light changes. Thus, an arbitrary illuminance distribution can be formed by controlling the swinging of the reflecting portion 230.

  FIG. 2 is a schematic exploded perspective view of one unit element 200. Each of the unit elements 200 is formed by combining the drive unit 220 and the reflection unit 230. In the spatial light modulator 100, each of the plurality of unit elements 200 has a similar structure individually.

  The drive unit 220 includes a pair of piezoelectric elements 222 that are upright with respect to the upper surface of the substrate 210 and are parallel to each other. Each of the piezoelectric elements 222 forms an electromechanical transducer including a columnar piezoelectric material and a pair of electrodes (not shown) that are disposed at both ends of the piezoelectric material and apply a driving voltage to the piezoelectric material.

  In addition, the upper end surface of each piezoelectric element 222 is covered with an insulating portion 224. Each lower end surface of the piezoelectric element 222 is fixed to the upper surface of the substrate 210 as indicated by a dotted line in the drawing. Each of the piezoelectric elements 222 is formed of a piezoelectric material such as PZT that expands or contracts by an applied voltage. In this embodiment, a piezoelectric material is used, but an electrostrictive material may be used.

  The reflection unit 230 includes a reflection surface 232, a reflection surface support portion 234, and a flexure 236. The reflective surface support portion 234 is a substrate that supports a layer that becomes the reflective surface 232, and supports the reflective surface 232 as a whole to maintain its flatness. The pair of flexures 236 extends downward from the lower surface of the reflecting surface support portion 234.

  Although the reflecting surface support part 234 and the flexure 236 are integrally formed, the reflecting surface support part 234 has a sufficient thickness and high bending rigidity. On the other hand, the flexure 236 is relatively thin with respect to the thickness of the reflecting surface support portion 234 and has a relatively low bending rigidity.

  The lower end of the flexure 236 is individually fixed to the upper end surface of the piezoelectric element 222 via an adhesive 238. As the adhesive 238, a solder alloy or the like can be used in addition to an adhesive such as an epoxy resin.

  Note that the reflecting surface support portion 234 and the flexure 236 can be integrally formed of, for example, single crystal silicon shaped by a lithography technique. Further, the reflection surface 232 can be formed of a metal film deposited on the upper surface of the reflection surface support portion 234, for example, an aluminum thin film.

  FIG. 3 is a schematic cross-sectional view of the unit element 200, showing the AA cross-section shown in FIG. Elements that are the same as those in FIG. 2 are given the same reference numerals, and redundant descriptions are omitted.

  As illustrated, the lower ends of the pair of piezoelectric elements 222 are fixed to the upper surface of the substrate 210. The upper ends of the pair of piezoelectric elements 222 are individually coupled to the lower ends of the flexure 236 via the insulating portion 224 and the adhesive 238. The flexure 236 supports the reflection surface support portion 234 from below. On the upper surface of the reflection surface support portion 234, the reflection surface 232 is supported substantially horizontally.

  4 is a schematic cross-sectional view of the unit element 200, and shows a state in which a drive voltage is applied to the piezoelectric element 222 of the unit element 200 shown in FIG. Elements common to FIGS. 2 and 3 are denoted by the same reference numerals, and redundant description is omitted.

  As shown in the drawing, the left piezoelectric element 222 in the drawing contracts with respect to the state shown in FIG. Further, the piezoelectric element 222 on the right side in the drawing is extended with respect to the state shown in FIG. As a result, the left side of the reflection surface support portion 234 in the figure is lowered, and the right side of the reflection surface support portion 234 in the drawing is raised. Therefore, the reflecting surface 232 is inclined toward the left in the figure. It goes without saying that the magnitude and direction of inclination can be changed by changing the drive voltage applied to the piezoelectric element 222.

  When the reflecting surface 232 is inclined, the flexure 236 is thin and easily deformed. Thereby, the stress generated when the reflecting surface support portion 234 swings is relieved, and deformation of the reflecting surface 232 due to the stress is prevented.

  In FIG. 4, one of the pair of piezoelectric elements 222 is contracted and the other is expanded. However, the reflecting portion 230 can be swung even when one side is expanded and contracted and the other side is fixed. Further, since many of the piezoelectric materials that can form the piezoelectric element 222 have high compressive strength, the piezoelectric element 222 may be operated only in the contraction direction.

  Referring to FIG. 1 again, each of the plurality of reflection units 230 can be individually controlled by individually controlling the driving power for the above-described structure provided in each of the reflection units 230. Therefore, an arbitrary irradiation pattern can be formed by once reflecting the light to the spatial light modulator 100 and can be used as a variable light source, an exposure device, an image display device, an optical switch, or the like.

  FIGS. 5 to 10 are cross-sectional views showing a manufacturing process of the spatial light modulator 100 shown in FIGS. Since FIGS. 5 to 10 show the manufacturing process, the corresponding elements of the spatial light modulator 100 may be included in different shapes or states. Therefore, after assigning unique reference numbers to these diagrams to explain the contents of each diagram, FIG. 10 shows the correspondence with the elements of the spatial light modulator 100.

  First, as shown in FIG. 5, a piezoelectric material is deposited on one surface on a substrate 310. Thereby, the piezoelectric material layer 320 is formed on the substrate 310.

  As a material of the substrate 210, a member having a flat surface such as a compound semiconductor substrate and a ceramic substrate can be widely used in addition to a silicon single crystal substrate. As a material of the piezoelectric material layer 320, for example, an oxide or a nitride of the material of the substrate 310 can be used. In addition, the method for forming the piezoelectric material layer 320 can be appropriately selected from various physical vapor deposition methods and chemical vapor deposition methods depending on the material.

  Next, as shown in FIG. 6, an insulating material is deposited on the entire top surface of the piezoelectric material layer 320. Thereby, a laminated structure in which the substrate 310, the piezoelectric material layer 320, and the insulating material layer 330 are laminated is formed. As a material of the insulating material layer 330, for example, an oxide or a nitride of the material of the substrate 310 can be used. The insulating material layer 330 may be a porous body having a high dielectric constant. A method for forming the insulating material layer 330 can be appropriately selected from various physical vapor deposition methods and chemical vapor deposition methods depending on the material.

  Next, as shown in FIG. 7, the laminate is patterned and formed into a columnar shape on the substrate 310. Here, for example, the piezoelectric material layer 320 can be patterned into a columnar shape by a deep reactive ion etching method in which the blank region is removed by high-density plasma while the object to be processed is cooled. In addition, the piezoelectric material layer 320 can be patterned into a columnar shape by a Bosch process in which a processing target is etched with sulfur hexafluoride gas or the like while protecting the etching side surface with a fluorine-based gas.

  In this way, a component is obtained in which the piezoelectric material layers 320 each having a columnar shape and one end bonded to the substrate 310 are arranged in a matrix on the substrate 310. The lower end of each piezoelectric material layer 320 is fixed to the substrate 310. Therefore, when a driving voltage is applied to the piezoelectric material layer 320, the piezoelectric material layer 320 expands and contracts in the normal direction of the substrate 310.

  Although not shown, the surface of the piezoelectric material layer 320 includes a step of forming an electrode for applying a driving voltage to the piezoelectric material layer 320. In addition, the substrate 310 may be provided with a wiring for supplying a voltage to the electrode.

  On the other hand, as shown in FIG. 8, one side of a separately prepared substrate 340 is processed by photolithography to form a large number of columnar portions 342. As a result, a plurality of columnar portions 342 can be collectively formed on the back surface of the substrate 340. Thus, a deformable columnar portion 342 is formed on one surface of the substrate 340.

  Since each of the columnar portions 342 is thin with respect to the entire substrate 340, the bending rigidity is low, and it easily deforms when stress is applied. Further, even when the columnar portion 342 is deformed, the stress caused by the deformation does not reach the surface of the substrate 340.

  Note that the columnar portion 342 is easily broken when the substrate 340 is alone. Therefore, as indicated by a dotted line in the figure, the columnar portion 342 is cured by the sacrificial layer 350 formed on the back surface of the substrate 340, and the back surface of the substrate 340 is flattened. Note that a resist or the like can be used for the sacrificial layer 350.

  Next, as shown in FIG. 9, the substrate 340 shown in FIG. 8 is bonded onto the patterned laminate shown in FIG. At this time, each of the columnar portions 342 of the substrate 340 is collectively bonded to the upper surface of the columnar stacked body. Further, in each of the columnar portions 342, the bonding location is limited to the lower end. Thus, the substrate 310 provided with the piezoelectric material layer 320 and the substrate 340 having the columnar portion 342 are integrated.

  Further, a reflective film material is deposited on the flat surface of the substrate 340 to form a reflective film 360. Examples of the material of the reflective film 360 include metals such as aluminum, copper, and chromium, or alloys thereof. The method for forming the reflective film 360 can be appropriately selected from various physical vapor deposition methods, chemical vapor deposition methods, plating methods, and the like depending on the material.

  Prior to the formation of the reflective film 360, the surface of the substrate 340 serving as the base may be mirror-polished by chemical mechanical polishing. Further, the surface of the reflective film 360 itself may be mirror-polished by chemical mechanical polishing. Further, both the substrate 340 and the reflective film 360 may be subjected to chemical mechanical polishing.

  Next, as shown in FIG. 10, first, the substrate 340 is cut while leaving the sacrificial layer 350, and then the sacrificial layer 350 is removed. Here, the columnar portion 342 is protected by cutting the substrate 340 while leaving the sacrificial layer 350. The substrate 340 can be cut by, for example, laser processing. Further, since the surface side of the substrate 340 and the sacrificial layer 350 communicate with each other by cutting, the sacrificial layer 350 can be easily removed with a liquid or gaseous etchant.

  Thus, the spatial light modulator 100 having the same structure as the spatial light modulator 100 shown in FIGS. 1 to 4 is formed. That is, the substrate 310 corresponds to the substrate 210, the piezoelectric material layer 320 and the insulating material layer 330 correspond to the driving unit 220, and the substrate 340 and the reflective film 360 correspond to the reflecting unit 230, respectively. Further, the columnar portion 342 shown in FIG. 8 corresponds to the flexure 236.

  The manufacturing method of the spatial light modulator 100 as described above is excellent in productivity because the flexure 236 having a fine structure can be collectively formed on the back surface of the substrate 340 by the lithography technique. In addition, since the substrates 340 corresponding to the plurality of reflection units 230 are collectively bonded to the plurality of drive units 220, the number of manufacturing steps of the spatial light modulator 100 can be reduced.

  Furthermore, since the reflecting surface support part 234 and the flexure 236 formed integrally are cut and divided in a state protected by the sacrificial layer 350, the flexure 236 is prevented from being damaged. Therefore, the manufacturing yield of the spatial light modulator 100 is increased.

  FIG. 11 is a perspective view of a spatial light modulator 100 having another structure. The spatial light modulator 100 has the same structure as the spatial light modulator 100 shown in FIG. Therefore, the same elements as those in FIG.

  The spatial light modulator 100 has the same structure as the spatial light modulator 100 shown in FIG. 1 in that the spatial light modulator 100 includes a substrate 210, a driving unit 220, and a reflection unit 230 that are sequentially stacked. However, the driving unit 220 is divided into a larger number with respect to one reflecting surface 232. Thereby, the reflecting surface 232 swings about a plurality of swinging shafts.

  12 is an exploded perspective view of the unit element 200 of the spatial light modulator 100 shown in FIG. Elements that are the same as those in FIG. 11 are given the same reference numerals, and redundant descriptions are omitted.

  The driving unit 220 includes two pairs of columnar piezoelectric elements 222 arranged on four corners of a rectangle on the substrate 210. Each of the piezoelectric elements 222 stands substantially vertically on the upper surface of the substrate 210 in parallel with each other. Each of the piezoelectric elements 222 has a pair of electrodes (not shown) and forms an electromechanical conversion unit that individually expands and contracts according to a voltage applied to the electrodes.

  The reflection unit 230 includes a reflection surface 232, a reflection surface support portion 234, and a flexure 236. Here, the number of the flexures 236 increases according to the number of the corresponding piezoelectric elements 222, and four are formed corresponding to the four corners of the reflecting surface support portion 234. In addition, each of the flexures 236 has a rectangular horizontal cross-sectional shape, and is arranged so that the long side surrounds the center of the reflection surface support portion 234.

  Although the reflecting surface support portion 234 and the flexure 236 are integrally formed, the reflecting surface support portion 234 has a sufficient thickness and high bending rigidity. On the other hand, the flexure 236 is relatively thin with respect to the thickness of the reflecting surface support portion 234 and has relatively low bending rigidity.

  FIG. 13 is a schematic cross-sectional view of the unit element 200, showing a cross section taken along the line BB shown in FIG. Elements common to FIG. 11 and FIG. 12 are assigned the same reference numerals, and redundant description is omitted.

  As illustrated, the lower end of the piezoelectric element 222 is fixed to the upper surface of the substrate 210. The upper end of the piezoelectric element 222 is individually coupled to the lower end of the flexure 236 via the insulating portion 224 and the adhesive 238. The flexure 236 supports the reflection surface support portion 234 from below. On the upper surface of the reflection surface support portion 234, the reflection surface 232 is supported substantially horizontally.

  14 is a schematic cross-sectional view of the unit element 200, and shows a state in which a drive voltage is applied to the piezoelectric element 222 of the unit element 200 shown in FIG. Elements common to FIGS. 12 and 13 are denoted by the same reference numerals, and redundant description is omitted.

  As shown in the drawing, the left piezoelectric element 222 in the drawing contracts with respect to the state shown in FIG. Further, the piezoelectric element 222 on the right side in the drawing is extended with respect to the state shown in FIG. The pair of piezoelectric elements 222 shown in the figure expands and contracts, whereas the pair of piezoelectric elements 222 not shown in the figure does not contract or extend.

  As a result, the left side of the reflection surface support portion 234 in the figure is lowered, and the right side of the reflection surface support portion 234 in the drawing is raised. Therefore, the reflecting surface 232 is inclined toward the left in the figure. As shown in FIG. 12, this unit element 200 has two pairs of piezoelectric elements 222. Therefore, by changing the combination of the piezoelectric elements 222 to be expanded and contracted, the reflecting surface support portion 234 is moved around an arbitrary swing axis. It can be swung. Further, by changing the drive voltage applied to the piezoelectric element 222, the magnitude and direction of the inclination can be changed.

  Furthermore, when the reflecting surface support part 234 and the reflecting surface 232 are swung, the thin flexure 236 is easily deformed. Thereby, since the stress generated when the reflecting surface support portion 234 swings is relieved, deformation of the reflecting surface 232 due to the stress is prevented.

  As described above, the spatial light modulator 100 formed by the unit element 200 including a large number of piezoelectric elements 222 can also be manufactured by a series of manufacturing steps shown in FIGS. That is, in the step of patterning the laminate of the piezoelectric material layer and the insulating material layer shown in FIG. 7, the drive unit 220 of the spatial light modulator 100 can be manufactured by changing the division pattern of the laminate.

  Further, by changing the pattern at the stage of forming the columnar portion 342 on the back surface of the substrate 340 shown in FIG. 8, a component in which the reflecting surface support portion 234 and the flexure 236 are integrated can be manufactured. Furthermore, the board | substrate 310 and the board | substrate 340 can be integrated by couple | bonding the drive part 220 and the flexure 236 by adhesion | attachment etc. FIG. Hereinafter, the process of forming the reflecting surface 232 and dividing the substrate 340 is the same as that shown in FIGS.

  FIG. 15 is an exploded perspective view of a unit element 200 having another structure. The unit element 200 has the same structure as that of the unit element 200 shown in FIG. 12 except for the portions described below. Further, the unit element 200 can form the spatial light modulator 100 shown in FIG. 11 in place of the unit element 200 shown in FIG. Therefore, the same elements as those in FIG.

  The unit element 200 has a structure unique to the flexure 236. That is, the flexure 236 includes a long plate-like member that is parallel to the lower surface of the reflection surface support portion 234 and extends in the diagonal direction of the reflection surface support portion 234. One end of the flexure 236 is bonded to the four corners of the lower surface on the lower surface of the reflecting surface support portion 234 by an adhesive 235. The other end of the flexure 236 is bonded to the inner corner by an adhesive 238 on the upper surface of each insulating portion 224.

  In addition, at least a part of the flexure 236 has a reduced width and a reduced bending rigidity. Thereby, the flexure 236 easily bends. Further, a recessed hole 237 is formed in a portion of the flexure 236 where the width is narrow. Thereby, high adhesive strength can be obtained with a narrow adhesive area with respect to the adhesive 238.

  FIG. 16 is a schematic cross-sectional view of the unit element 200, and shows a cross section taken along the line CC shown in FIG. Elements that are the same as those in FIG. 15 are given the same reference numerals, and redundant descriptions are omitted.

  As shown, the adhesives 235, 238 have their own thickness even after bonding the flexure 236. As a result, the central portion of each of the bonded flexures 236 is in a state of being separated from the reflecting surface support portion 234 and the insulating portion 224. Therefore, the flexure 236 can be uniquely deformed without affecting the reflecting surface support portion 234.

  FIG. 17 is a schematic cross-sectional view of the unit element 200, and shows a state in which a driving voltage is applied to the piezoelectric element 222 of the unit element 200 shown in FIG. Elements common to FIGS. 15 and 16 are denoted by the same reference numerals, and redundant description is omitted.

  As shown in the drawing, the left piezoelectric element 222 in the drawing contracts with respect to the state shown in FIG. Further, the piezoelectric element 222 on the right side in the drawing extends with respect to the state shown in FIG. Further, in the unit element 200, the pair of piezoelectric elements 222 not shown are not contracted or expanded. Thereby, the reflecting surface support portion 234 swings as illustrated.

  When the reflecting surface support portion 234 and the reflecting surface 232 are swung, the flexure 236 is easily deformed to relieve stress generated in the reflecting surface support portion 234. Thereby, the deformation of the reflecting surface 232 is prevented.

  The spatial light modulator 100 including a plurality of unit elements 200 as described above can also be manufactured by a series of manufacturing processes shown in FIGS. If the step of forming the columnar portion 342 on the back surface of the substrate 340 shown in FIG. 8 is changed, the step of integrating the substrate 310 and the substrate 340 and the step of dividing the substrate 340 are shown in FIG. 9 and FIG. It can be carried out in the same way as the case.

  Note that the flexure 236 can be made of the same material as the reflective surface support portion 234. The flexure 236 may be made of other materials such as a metal film. As the adhesives 235 and 238, a solder alloy, a resin, or the like can be used.

  Further, the flexure 236 may be formed integrally with the reflective surface support portion 234 without the adhesive 235. Such a flexure 236 can be formed by processing the back surface of the reflecting surface support portion 234 by photolithography. However, in this case as well, it is preferable that a part of the flexure 236 be separated from the back surface of the reflecting surface support portion 234.

  FIG. 18 is an exploded perspective view of a unit element 200 having another structure. The unit element 200 has the same structure as the unit element 200 shown in FIGS. 12 and 15 except for the parts described below. Further, the unit element 200 can form the spatial light modulator 100 shown in FIG. 11 in place of the unit element 200 shown in FIGS. Therefore, the same elements as those in FIGS. 12 and 15 are denoted by the same reference numerals, and redundant description is omitted.

  The unit element 200 uses an elastic sheet formed of a material that is easily elastically deformed as the flexure 236. As a material of the flexure 236, a sheet of elastomer such as silicon rubber can be used. The flexure 236 formed by the elastic sheet has substantially the same area as the lower surface of the reflection surface support portion 234.

  However, as indicated by hatching in the drawing, the flexure 236 is bonded to the lower surface of the reflecting surface support portion 234 by an adhesive 235 in a partial bonding region. Similarly, the upper end surface of the insulating portion 224 is bonded by the adhesive 238 in a partial bonding region. As the adhesives 235 and 238, it is preferable to select a material having high adhesive strength with respect to any of the insulating portion 224, the reflecting surface support portion 234, and the flexure 236, such as modified silicon and epoxy resin. It is also preferable that the adhesives 235 and 238 themselves are materials that are easily elastically deformed.

  FIG. 19 is a schematic cross-sectional view of the unit element 200, showing a DD cross section shown in FIG. Elements that are the same as those in FIG. 18 are given the same reference numerals, and redundant descriptions are omitted.

  As illustrated, the flexure 236 is filled between the insulating portion 224 and the reflecting surface support portion 234. However, the flexure 236 is joined by the adhesives 235 and 238 in part of the reflective surface support portion 234 or the insulating portion 224. In the illustrated example, the adhesive materials 235 and 238 are arranged at the same position, but the positions of the adhesive materials 235 and 238 may be shifted on the front and back of the flexure 236. Thereby, deformation in the surface direction of the flexure 236 can also be used.

  20 is a schematic cross-sectional view of the unit element 200, and shows a state in which a driving voltage is applied to the piezoelectric element 222 of the unit element 200 shown in FIG. Elements common to FIGS. 18 and 19 are denoted by the same reference numerals, and redundant description is omitted.

  As shown in the drawing, the left piezoelectric element 222 in the drawing contracts with respect to the state shown in FIG. Further, the piezoelectric element 222 on the right side in the drawing is extended with respect to the state shown in FIG. In the unit element 200, a pair of piezoelectric elements 222 not shown are not contracted or expanded. Thereby, the reflecting surface support portion 234 swings as illustrated.

  When the reflecting surface support portion 234 and the reflecting surface 232 are swung, the flexure 236 is easily deformed to relieve stress generated in the reflecting surface support portion 234. Thereby, the deformation of the reflecting surface 232 is prevented.

  The spatial light modulator 100 including a plurality of unit elements 200 as described above can also be manufactured by a series of manufacturing processes shown in FIGS. If the step of forming the columnar portion 342 on the back surface of the substrate 340 shown in FIG. 8 is changed so as to attach an elastic sheet, the step of integrating the substrate 310 and the substrate 340 and the step of dividing the substrate 340 are: This can be implemented in the same manner as shown in FIGS. The elastic sheet as the flexure 236 is divided together with the substrate 340.

  FIG. 21 is an exploded perspective view of a unit element 200 having another structure. The unit element 200 has the same structure as the unit element 200 shown in FIGS. 12, 15 and 18 except for the parts described below. Further, the unit element 200 can form the spatial light modulator 100 shown in FIG. 11 in place of the unit element 200 shown in FIGS. 12, 15 and 18. Elements common to FIGS. 12, 15 and 18 are given the same reference numerals and redundant description is omitted.

  The unit element 200 has a structure unique to the flexure 236. That is, the flexure 236 is formed of a substantially spherical solder alloy attached to the lower surface of the reflecting surface support portion 234. The lower end of the flexure 236 is bonded to the upper surface of each insulating portion 224.

  The flexure 236 formed of a solder alloy also serves as an adhesive for the reflecting surface support portion 234 and the insulating portion 224. For this reason, in this unit element 200, the adhesive 238 is omitted.

  Further, the flexure 236 formed of a solder alloy relieves the stress generated in the reflecting surface support portion 234 by itself deforming. Therefore, a solder alloy having a low bending rigidity in a solid state is preferably selected.

  Furthermore, it is preferable that the solder alloy has a lower melting point than any of the substrate 210, the piezoelectric element 222, the insulating portion 224, and the reflecting surface support portion 234. As a result, the flexure 236 can be melted without damaging existing components due to heat, and the drive unit 220 and the reflection unit 230 can be coupled.

  22 is a cross-sectional view of the unit element 200, showing a cross section taken along line EE shown in FIG. Elements that are the same as those in FIG. 21 are given the same reference numerals, and redundant descriptions are omitted.

  As shown in the drawing, the flexure 236 formed of a solder alloy has its own height even after being bonded to the reflecting surface support portion 234 and the insulating portion 224. As a result, the central portion of each of the flexures 236 deforms itself without deforming the reflecting surface support portion 234 when the inclinations of the reflecting surface support portion 234 and the insulating portion 224 change with each other.

  FIG. 23 is a schematic cross-sectional view of the unit element 200, showing a state in which a drive voltage is applied to the piezoelectric element 222 of the unit element 200 shown in FIG. Elements common to FIGS. 21 and 22 are denoted by the same reference numerals, and redundant description is omitted.

  As shown in the drawing, the left piezoelectric element 222 in the drawing contracts with respect to the state shown in FIG. Further, the piezoelectric element 222 on the right side in the drawing is extended with respect to the state shown in FIG. Further, in the unit element 200, the pair of piezoelectric elements 222 not shown are not contracted or expanded. Thereby, the reflecting surface support portion 234 swings as illustrated.

  When the reflecting surface support portion 234 and the reflecting surface 232 are swung, the flexure 236 is deformed to relieve stress generated in the reflecting surface support portion 234. Thereby, the deformation of the reflecting surface 232 is prevented.

  The spatial light modulator 100 including a plurality of unit elements 200 as described above can also be manufactured by a series of manufacturing processes shown in FIGS. The step of forming the columnar portion 342 on the back surface of the substrate 340 shown in FIG. 8 can be omitted. The step of integrating the substrate 310 and the substrate 340 and the step of dividing the substrate 340 can be performed similarly to the case shown in FIGS.

  FIG. 24 is a schematic diagram of the exposure apparatus 400. The exposure apparatus 400 includes the spatial light modulator 100 and can make illumination light having an arbitrary illuminance distribution incident on the illumination optical system 600 when executing the light source mask optimization method. That is, the exposure apparatus 400 includes an illumination light generator 500, an illumination optical system 600, and a projection optical system 700.

The illumination light generator 500 includes a light source 520, a controller 510, a spatial light modulator 100, a prism 530, an imaging optical system 540, a beam splitter 550, and a measuring unit 560. The light source 520 generates illumination light L. The illumination light L generated by the light source 520 has an illuminance distribution according to the characteristics of the light emitting mechanism of the light source 520. For this reason, the illumination light L has the original image I ₁ in a cross section orthogonal to the optical path of the illumination light L.

  The illumination light L emitted from the light source 520 enters the prism 530. The prism 530 guides the illumination light L to the spatial light modulator 100 and then emits the light again to the outside. The spatial light modulator 100 modulates the illumination light L incident under the control of the control unit 510. The structure and operation of the spatial light modulator 100 are as described above.

The illumination light L emitted from the prism 530 via the spatial light modulator 100 is incident on the illumination optical system 600 at the subsequent stage via the imaging optical system 540. The imaging optical system 540 forms an illumination light image I ₃ on the incident surface 612 of the illumination optical system 600.

  The beam splitter 550 is disposed on the optical path of the illumination light L between the imaging optical system 540 and the illumination optical system. The beam splitter 550 separates a part of the illumination light L before entering the illumination optical system 600 and guides it to the measurement unit 560.

The measurement unit 560 measures an image of the illumination light L at a position optically conjugate with the incident surface 612 of the illumination optical system 600. Thereby, the measurement unit 560 measures the same image as the illumination light image I ₃ incident on the illumination optical system 600. Therefore, the control unit 510 refers to the illumination light image I ₃ which is measured by the measuring unit 560 can be feedback controlled spatial light modulator 100.

  The illumination optical system 600 includes a fly-eye lens 610, a condenser optical system 620, a field stop 630, and an imaging optical system 640. A mask stage 720 holding a mask 710 is disposed at the exit end of the illumination optical system 600.

The fly-eye lens 610 includes a large number of lens elements arranged densely in parallel, and forms a secondary light source including illumination light images I ₃ as many as the number of lens elements on the rear focal plane. The condenser optical system 620 collects the illumination light L emitted from the fly-eye lens 610 and illuminates the field stop 630 in a superimposed manner.

The illumination light L that has passed through the field stop 630 forms an irradiation light image I ₄ that is an image of the opening of the field stop 630 on the pattern surface of the mask 710 by the imaging optical system 640. Thus, the illumination optical system 600, the pattern surface of the mask 710 disposed at its exit end, Koehler illuminated by illumination light image I _4.

Note that the illuminance distribution formed at the entrance end of the fly-eye lens 610, which is also the entrance surface 612 of the illumination optical system 600, is as high as the overall illuminance distribution of the entire secondary light source formed at the exit end of the fly-eye lens 610. Show correlation. Therefore, the illumination light image I ₃ that the illumination light generation unit 500 enters the illumination optical system 600 is also reflected in the illumination light image I ₄ that is the illuminance distribution of the illumination light L that the illumination optical system 600 irradiates the mask 710. .

  The projection optical system 700 is disposed immediately after the mask stage 720 and includes an aperture stop 730. The aperture stop 730 is disposed at a position optically conjugate with the exit end of the fly-eye lens 610 of the illumination optical system 600. A substrate stage 820 that holds a substrate 810 coated with a photosensitive material is disposed at the exit end of the projection optical system 700.

The mask 710 held on the mask stage 720 has a mask pattern including a region that reflects or transmits the illumination light L irradiated by the illumination optical system 600 and a region that absorbs the light. Therefore, by irradiating the illumination light image I ₄ to the mask 710, the projection light image I ₅ is generated by the interaction between the mask pattern of the mask 710 and the illuminance distribution of the illumination light image I ₄ itself. The projected light image I ₅ is projected onto the photosensitive material of the substrate 810 to form a resist layer having the required pattern on the surface of the substrate 810.

  In FIG. 24, the optical path of the illumination light L is drawn in a straight line, but the exposure apparatus 400 can be downsized by bending the optical path of the illumination light L. In FIG. 24, the illumination light L is drawn so as to pass through the mask 710, but a reflective mask 710 may be used.

  FIG. 25 is a partially enlarged view of the illumination light generation unit 500 and shows the role of the spatial light modulator 100 in the exposure apparatus 400. The prism 530 has a pair of reflecting surfaces 532 and 534. The illumination light L incident on the prism 530 is irradiated toward the spatial light modulator 100 by the one reflecting surface 532.

As already described, the spatial light modulator 100 has a plurality of reflecting portions 230 that can be individually swung. Therefore, the control unit 510 controls the spatial light modulator 100 can be formed of any light source image I ₂ corresponding to the request.

The light source image I ₂ emitted from the spatial light modulator 100 is reflected by the other reflecting surface 534 of the prism 530 and emitted from the right end surface of the prism 530 in the drawing. The light source image I ₂ emitted from the prism 530 forms an illumination light image I ₃ on the incident surface 612 of the illumination optical system 600 by the imaging optical system 540.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of the operations, procedures, steps and steps of the apparatus and system shown in the claims, the description, and the drawings is not clearly indicated as “before”, “prior”, etc. Unless the output of the previous process is used in the subsequent process, it can be realized in any order. In the claims, the description, and the drawings, even if “first”, “next”, and the like are used for convenience, it does not mean that it is essential to implement in this order.

100 Spatial Light Modulator, 200 Unit Element, 210, 310, 340 Substrate, 220 Drive Unit, 222 Piezoelectric Element, 224 Insulator, 230 Reflector, 232 Reflective Surface, 234 Reflective Surface Support, 235, 238 Adhesive, 236 Flexure, 237 Depression hole, 320 Piezoelectric material layer, 330 Insulating material layer, 342 Columnar part, 350 Sacrificial layer, 360 Reflective film, 400 Exposure device, 500 Illumination light generation part, 510 Control part, 520 Light source, 530 Prism, 532, 534 Reflective surface, 540, 640 Imaging optical system, 550 Beam splitter, 560 Measurement unit, 600 Illumination optical system, 612 Incident surface, 610 Fly eye lens, 620 Condenser optical system, 630 Field stop, 700 Projection optical system, 710 Mask 720 Mask stage 730 Aperture stop 8 10 substrate, 820 substrate stage

Claims (12)

A method of manufacturing a spatial light modulator, comprising:
A coupling step of coupling one end of the electromechanical conversion unit that expands and contracts by an electrical signal to the driving side substrate;
Forming a deformable stress relieving part on the back side of the surface supporting the reflecting part in the driven substrate that supports the reflecting part that reflects light; and
An integration step of coupling the other end of the electromechanical conversion unit to the stress relaxation unit and integrating the driving side substrate and the driven side substrate. In the coupling step, a plurality of the electromechanical conversion units are coupled to the driving side substrate,
In the forming step, a plurality of the stress relaxation portions are formed on the driven side substrate,
The manufacturing method according to claim 1, wherein, in the integration step, a plurality of the electromechanical conversion unit and the stress relaxation unit are coupled together.   The manufacturing method according to claim 2, further comprising a dividing step of cutting and dividing the driven substrate after the integrating step.   4. The manufacturing method according to claim 1, wherein, in the forming step, the stress relaxation portion includes a photolithography stage in which a back surface of the driving side substrate is processed by photolithography. 5.   The manufacturing method according to claim 4, wherein the photolithography step includes a step of forming the stress relaxation portion protruding from a back surface of the driven substrate.   The photolithography step includes the step of forming the stress relieving portion having one end coupled to the back surface of the driven substrate and extending in parallel with the back surface while being separated from the back surface of the driven substrate. 4. The production method according to 4.   The manufacturing method according to claim 1, wherein the forming step includes a step of attaching an elastic sheet to a back surface of the driven side substrate.   The forming step includes a step of attaching the stress relaxation portion formed of a material having rigidity and melting point lower than those of the driving side substrate and the driven side substrate to the back surface of the driven side substrate. The manufacturing method in any one of Claim 3 to Claim 3.   The manufacturing method according to claim 8, wherein the forming step includes a step of attaching a sphere formed of a solder alloy to a back surface of the driven side substrate.   A spatial light modulator manufactured by the method according to claim 1.   An illumination light generator comprising the spatial light modulator according to claim 10.   An exposure apparatus comprising the illumination light generator according to claim 11.

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