JP5848802B2 - Optical device, optical device manufacturing method, and exposure apparatus - Google Patents

Description

  The present invention relates to an optical device having a periodically poled structure (hereinafter, simply referred to as “optical device”), a method of manufacturing the optical device, and an exposure apparatus using the optical device.

Conventionally, ferroelectric crystals such as lithium niobate (LiNbO ₃ ) and lithium tantalate (LiTaO ₃ ) have been studied for application to optical devices for the purpose of controlling light modulation and wavelength conversion. Yes. For example, Non-Patent Document 1 describes a Bragg deflection type optical modulator using a ferroelectric crystal having a periodically poled structure. For example, Non-Patent Document 2 describes a wavelength conversion element using planar waveguide periodic polarization inversion (MgO: LN (PPMgLN)).

H.Gnewuch et al "Nanosecond Response of Bragg Deflectors inPeriodically Poled LiNbO3", IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 10, NO. 12, DECEMBER 1998 Yoshihito Hirano, “Ultra-small wavelength conversion green laser and laser TV”, Applied Physics Vol. 78, No. 11 (2009)

  By the way, in the optical modulator described in Non-Patent Document 1, light modulation is possible using the electro-optic effect, but the thickness of the ferroelectric crystal is about 300 μm and the polarization inversion period is as coarse as 40 μm. Since the drive voltage is also required to be 25 V or more, high-speed modulation is difficult. Therefore, in order to obtain further high-speed modulation, it is necessary to lower the drive voltage. One approach to achieve this is to reduce the thickness of the ferroelectric crystal (also called thinning). That is, the distance between the electrodes for applying a voltage to the ferroelectric crystal is shortened by reducing the thickness of the ferroelectric crystal, and the driving voltage can be reduced. Further, in the wavelength conversion element, a polarization inversion period of 3 μm is realized on a waveguide having a width of several μm. However, by improving the fabrication accuracy of the polarization inversion structure and shortening the polarization inversion period, a short wavelength of the conversion wavelength is achieved. It is hoped that it will respond to

  A voltage application method (also referred to as an electric field application method, a pulse electric field application method, or the like) is currently the mainstream as a method for forming a periodically poled structure. In this voltage application method, a lattice-like electrode is formed on one side of a ferroelectric crystal having a thickness of 150 μm to 500 μm, and a high voltage exceeding the polarization inversion voltage, which is a characteristic unique to the material, between the electrode provided on the other side Is applied to reverse the direction of polarization. For this reason, the cycle is short, about 3 μm, and it is extremely difficult to maintain uniform accuracy over a wide area.

  The present invention has been made in view of the above problems, and relates to an optical device in which a periodically poled structure is formed on a ferroelectric substrate composed of a ferroelectric crystal. It is an object of the present invention to provide a technique that can improve the accuracy of an inverted structure.

In order to achieve the above object, the first aspect of the optical device according to the present invention has a periodically poled structure periodically polarized in a first polarization direction and a second polarization direction opposite to the first polarization direction. Sandwiched between a ferroelectric substrate composed of a ferroelectric crystal, a support substrate, one main surface of the ferroelectric substrate, and one main surface of the support substrate facing the one main surface of the ferroelectric substrate with strong and joint the dielectric substrate to be integrated with supported by the supporting substrate, the bonding portion includes a first metal layer formed on one main surface of the ferroelectric substrate, one surface of the support substrate and a second metal layer that is formed is a conductive layer which is joined, the first metal layer and the second metal layer, consistent with the period of the domain portion in a first polarization direction in periodically poled A pattern is formed.

  According to a first aspect of the method for manufacturing an optical device of the present invention, in order to achieve the above object, one main surface of a ferroelectric substrate formed of a ferroelectric crystal and one main surface of a support substrate are provided. A first step of integrating the ferroelectric substrate while supporting the ferroelectric substrate with a support substrate with a conductive joint interposed therebetween, and a second step of forming a pattern electrode having a periodic pattern on the other main surface of the ferroelectric substrate. And a third step of periodically forming a domain-inverted portion on the ferroelectric substrate by applying a voltage between the pattern electrode and the junction, and the first step is one of the main steps of the ferroelectric substrate. A first metal layer forming step for forming a first metal layer having a pattern corresponding to the periodic pattern on the surface; and a second metal for forming a second metal layer having a pattern corresponding to the periodic pattern on one main surface of the support substrate. Layer forming step and convexity of pattern of first metal layer And an integration step of joining the convex portion of the second metal layer and forming the joint portion so that the ferroelectric substrate is supported by the support substrate. .

In order to achieve the above object, the second aspect of the optical device according to the present invention is a periodically poled structure periodically polarized in the first polarization direction and the second polarization direction opposite to the first polarization direction. A ferroelectric substrate composed of a ferroelectric crystal, a support substrate, an insulating layer formed on one main surface of the ferroelectric substrate, an insulating layer, and a support facing the one main surface of the insulating layer A junction part sandwiched between one main surface of the substrate and supporting the ferroelectric substrate with the support substrate through the insulating layer, and the junction part is formed on the one main surface of the insulating layer. a first metal layer and a conductive layer and a second metal layer formed on one main surface of the supporting substrate is bonded to the first metal layer and the second metal layer, periodically poled A pattern that coincides with the period of the portion polarized in the first polarization direction is formed. It is characterized in.

  According to a second aspect of the method for manufacturing an optical device of the present invention, in order to achieve the above object, one main surface of a ferroelectric substrate composed of a ferroelectric crystal and one main surface of a support substrate are provided. A first step of integrating the ferroelectric substrate while supporting the ferroelectric substrate with a support substrate with a conductive joint interposed therebetween, and a second step of forming a pattern electrode having a periodic pattern on the other main surface of the ferroelectric substrate. And a third step of periodically forming a domain-inverted portion on the ferroelectric substrate by applying a voltage between the pattern electrode and the junction, and the first step is one of the main steps of the ferroelectric substrate. An insulating layer forming step of forming an insulating layer on the surface; a first metal layer forming step of forming a first metal layer having a pattern corresponding to the periodic pattern on one main surface of the insulating layer; Forming a second metal layer having a pattern corresponding to the periodic pattern The second metal layer forming step, the convex portion of the pattern of the first metal layer, and the convex portion of the second metal layer are joined to form a joined portion, whereby the ferroelectric substrate is interposed via the insulating layer And an integration step of integrating them while supporting them with a support substrate.

  In the invention thus configured (optical device and method for manufacturing the same), since the ferroelectric substrate having a periodically poled structure is supported by the support substrate via the junction, the ferroelectric having the periodically poled structure is provided. Crystal thinning is possible. In addition, it is possible to manufacture the periodic polarization inversion structure with high accuracy. Therefore, for example, when an optical modulator is configured using the optical device described above, since the crystal thickness of the ferroelectric crystal having a periodically poled structure is thin, the distance between the electrodes is short, and the driving voltage can be kept low. High-speed modulation is possible. Further, for example, in the wavelength conversion element using the optical device, it is possible to produce a domain-inverted structure with a short period by thinning, and the conversion wavelength can be further shortened. In addition, since a highly accurate periodic polarization reversal structure, that is, a periodic polarization reversal structure that is uniform and has little periodic variation, a conversion efficiency can be improved. Furthermore, since the applied voltage for forming the domain-inverted structure can be further reduced, the operation can be performed safely.

  Here, as for the bonding portion, in the first aspect, the first metal layer formed on one main surface of the ferroelectric substrate and the second metal layer formed on one main surface of the support substrate are bonded. In the second mode, the first metal layer formed on one main surface of the ferroelectric substrate via the insulating layer is bonded to the second metal layer formed on one main surface of the support substrate. Have been made. As a result, the bonding strength between the ferroelectric substrate and the support substrate can be increased.

  Further, in the second aspect of the optical device and the optical device manufacturing method, since the insulating layer is interposed between the one main surface of the ferroelectric substrate and the bonding portion, the ferroelectric substrate and the bonding portion Leakage current can be prevented from flowing between them. This is particularly advantageous when a domain-inverted structure is produced by a so-called voltage application method. This effect will be described in detail in a later embodiment.

  Further, as described above, an insulating layer (second insulating layer) may be formed on the other main surface of the ferroelectric substrate provided with the insulating layer (first insulating layer) on one main surface. In this case, a region sandwiched between these two insulating layers is a step index type waveguide. Further, a proton exchange waveguide may be formed in at least one of the vicinity of the surface of the one main surface and the surface of the other main surface of the ferroelectric substrate.

Further, in the optical device, in the conductive layer, the first metal layer and the second metal layer may be joined by irradiation with an argon fast atom beam. May have an activation step of activating the convex portions of the pattern of the first metal layer and the convex portions of the second metal layer by irradiating with an argon fast atom beam.

  It is also possible to configure an optical modulator using the optical device configured as described above and apply it to an exposure apparatus. That is, in an exposure apparatus that irradiates a surface to be exposed with modulated light obtained by modulating light emitted from a light source with an optical modulator, the optical modulator includes the optical device and the other of the ferroelectric substrate. It is configured to have a plurality of electrodes arranged on the main surface side and a modulation unit that modulates the diffraction efficiency in the ferroelectric substrate by controlling the generation of electric fields between the plurality of electrodes and the junction, respectively. May be. In addition, as an aspect of an optical device suitable for application to an optical modulator, for example, the optical device further includes a plurality of electrodes formed on the other main surface of the ferroelectric substrate, and between the plurality of electrodes and the joint. Some are configured such that when an electric field is generated, the diffraction efficiency in the periodically poled structure is modulated. That is, the optical device configured in this manner functions as a light modulation element of the light modulator.

  The material and structure of the support member are arbitrary, but the support member may be made of the same crystal as the ferroelectric crystal of the ferroelectric substrate, or the absolute value of the crystal orientation of the crystal constituting the support substrate may be ferroelectric. The substrate may be configured to coincide with the absolute value of the crystal orientation of the ferroelectric crystal of the substrate. Therefore, in the manufacturing method of the optical device, the support substrate is composed of the same crystal as the ferroelectric crystal of the ferroelectric substrate, and the integration step is the absolute orientation of the crystal orientation of the support substrate and the ferroelectric substrate. You may make it join a 1st metal layer and a 2nd metal layer, making a value correspond mutually.

  In consideration of application to an optical modulator or a wavelength conversion element of an optical device, a thickness of 0.1 μm to 200 μm is preferable as the ferroelectric crystal of the ferroelectric substrate. At this time, in the optical device, the support substrate may be configured to be thicker than the ferroelectric substrate. In the optical device manufacturing method, the surface region on the other main surface side of the ferroelectric substrate integrated with the support substrate is used. A fourth step of adjusting the thickness of the ferroelectric crystal to 0.1 μm to 200 μm may be further provided.

  In addition, it further includes a plurality of electrodes formed on the other main surface of the ferroelectric substrate, and when an electric field is generated between the plurality of electrodes and the junction, the diffraction efficiency in the periodically poled structure is modulated. As such, an optical device may be configured.

  As described above, according to the present invention, the ferroelectric substrate composed of the ferroelectric crystal is bonded to the support substrate by the bonding portion, and the periodically poled structure is formed on the ferroelectric substrate. . Therefore, the ferroelectric crystal can be thinned, and a highly accurate periodic polarization inversion structure can be obtained.

It is sectional drawing which shows 1st Embodiment of the optical device concerning this invention. It is a figure which shows the manufacturing method of the optical device shown in FIG. It is a figure which shows the manufacturing method of the optical device shown in FIG. It is a figure which shows the manufacturing method of the optical device shown in FIG. It is sectional drawing which shows 2nd Embodiment of the optical device concerning this invention. It is a schematic diagram which shows the manufacturing method of the optical device shown in FIG. It is sectional drawing which shows 3rd Embodiment of the optical device concerning this invention. It is sectional drawing which shows 4th Embodiment of the optical device concerning this invention. It is sectional drawing which shows 5th Embodiment of the optical device concerning this invention. It is a perspective view which shows the pattern drawing apparatus equipped with the optical modulator to which the optical device concerning this invention is applied. It is a side view of the pattern drawing apparatus shown in FIG. It is a block diagram which shows the electrical constitution of the pattern drawing apparatus of FIG. It is a figure which simplifies and shows the internal structure of an optical head. It is a figure which shows an example of the spatial light modulator to which the optical device of FIG. 1 is applied. It is a figure which shows the other example of the spatial light modulator to which the optical device of FIG. 1 is applied. It is a figure which shows an example of the wavelength conversion element to which the optical device of FIG. 1 is applied. It is a figure which shows the other of the wavelength conversion element to which the optical device of FIG. 1 is applied.

<First Embodiment>
FIG. 1 is a sectional view showing a first embodiment of an optical device according to the present invention. This optical device 1A includes a ferroelectric substrate 11 made of a ferroelectric crystal having a periodically poled structure (Periodically Poled), and includes an insulating layer 12 such as SiO ₂ and a junction 13 having a four-layer structure. The ferroelectric substrate 11 is supported by the support substrate 14 via In this embodiment, a treatment described later is performed on a single crystal substrate of lithium niobate (MgO) or stoichiometric lithium thantalate (MgO) to which magnesium oxide (MgO) is added. A ferroelectric substrate 11 having a periodically poled structure is formed in a thin film shape. In the following, lithium niobate to which magnesium oxide (MgO) has been added is referred to as “MgO: LN”, and stoichiometric lithium tantalate is referred to as “MgO: SLT”. An insulating layer 12 is uniformly formed on the entire lower surface of the ferroelectric substrate 11. Further, a chromium (Cr) film 13a and a gold (Au) film 13b are formed in this order on the insulating layer 12, and a first metal layer having a two-layer structure is formed by the chromium film 13a and the gold film 13b. .

  The support substrate 14 is a plate-like member that is thicker than the ferroelectric substrate 11 having a periodically poled structure. In this embodiment, the support substrate 14 has the same composition as the ferroelectric substrate 11 and has an absolute value of crystal orientation. It is composed of a single crystal substrate of MgO: LN or MgO: SLT that matches the ferroelectric substrate 11. In the first embodiment, as shown in FIG. 1, the support substrate 14 is formed to be longer than the ferroelectric substrate 11, which is used when the optical device 1 </ b> A is manufactured by a method described later. Considering the rationality and rationality when used as an optical modulator as will be described later, the substrate shape is not limited to this, and is arbitrary. For example, the third embodiment to the later Needless to say, the same shape as that of the ferroelectric substrate 11 may be used as in the fifth embodiment. Further, the material and composition of the support substrate 14 are also arbitrary. However, it is preferable that the support substrate 14 is made of the same crystal as the ferroelectric substrate 11 as in the first embodiment because the environmental resistance can be improved. The same applies to the optical device described later.

  A chromium (Cr) film 13d is uniformly formed on the entire top surface of the support substrate 14 thus configured, and a gold (Au) film 13c is uniformly formed on the top surface of the chromium film 13d. Thus, a second metal layer having a two-layer structure composed of the chromium film 13 d and the gold film 13 c is formed on the upper surface of the support substrate 14. Then, the gold film 13c constituting the second metal layer is joined to the gold film 13b constituting the first metal layer to form a joint portion 13 having a four-layer structure, whereby the ferroelectric substrate 11 is It is integrated with the support substrate 14. The detailed shape and bonding state will be described in detail with reference to the manufacturing method described below.

  2 to 4 are views showing a method of manufacturing the optical device shown in FIG. The upper drawing in FIG. 3 is a plan view seen from above, and the lower drawing is a cross-sectional view taken along line AA of the plan view. 4 is a plan view seen from above, and the lower drawing is a cross-sectional view of the plan view. In the present embodiment, first, strip-shaped chips CA and CB having the same size as the support substrate 14 are obtained from the monopolarized single crystal wafer of MgO: LN or MgO: SLT, respectively, of the ferroelectric substrate 11 and the support substrate 14. Cut out as raw material. At this time, a notch indicating the crystal orientation is provided as a marker for each of the chips CA and CB. Then, the chips CA and CB are mounted on the jig with the one main surface S1A of the chip CA facing upward and the one main surface S1B of the chip CB facing upward. Then, the insulating layer 12 is formed only on the one main surface S1A of the chip CA. Subsequently, a chromium film and a gold film are formed in this order on the insulating layer 12 of the chip CA and the one main surface S1B of the chip CB by sputtering. Thus, in the chip CA, the insulating layer 12, the chromium film 13a and the gold film 13b are formed on the one main surface S1A of the ferroelectric substrate 11, and at the same time, in the chip CB, the chromium is formed on the one main surface S1B of the support substrate 14. A film 13d and a gold film 13c are formed (FIG. 2A). In the first embodiment, the chromium film and the gold film are formed by sputtering, but may be formed by a method such as vapor deposition.

  Next, after the chips CA and CB are taken out of the jig, the gold films 13b and 13c are irradiated with an argon fast atom beam (FAB) to activate the chip surface. Then, the chip CA is turned upside down, the gold film 13b of the chip CA is brought into close contact with the gold film 13c of the chip CB, and the chip CA is stacked and bonded on the chip CB (FIG. 2B). By this FAB bonding, a joint portion 13 having a four-layer structure is formed, and the chips CA and CB are integrated. At this time, as shown in FIG. 5B, the chips CA and CB are stacked in the vertical direction while being shifted from each other by a distance W in the longitudinal direction of the chips CA and CB (left and right direction in the drawing). Note that the bonding is not limited to FAB bonding, but may be bonding by oxygen plasma hydrophilization treatment or the like. Moreover, joining by soldering may be used.

  The other main surface of the chip CA integrated with the chip CB, that is, the other main surface S2A of the ferroelectric substrate 11 is planarly polished to thin the ferroelectric substrate 11 (FIG. 2C). In consideration of applying the optical device 1A to an optical modulator or a wavelength conversion element as will be described later, it is desirable to reduce the thickness to a thickness of 0.1 μm to 200 μm. This is the same in other embodiments described later.

  As described above, in the first embodiment, since the ferroelectric substrate 11 is integrated with the support substrate 14 via the insulating layer 12 and the joint portion 13, the ferroelectric substrate 11 can be precisely formed to a desired film thickness. Thin film can be easily formed. Further, when comparing the thicknesses of the ferroelectric substrate 11 and the support substrate 14 after polishing, the support substrate 14 is naturally the same thickness as the wafer, and is sufficiently thicker than the ferroelectric substrate 11 after polishing. The thin ferroelectric substrate 11 can be firmly supported.

  Then, after removing the end portion 11a of the chip CA protruding in the longitudinal direction from the chip CB and aligning it with the end surface of the chip CB (FIG. 2D), the resist layer 15 having a plurality of recesses 15a provided periodically is formed. It is formed on the other main surface S2A of the ferroelectric substrate 11 (FIG. 3A). More specifically, after a photoresist film is applied to the other main surface S2A of the ferroelectric substrate 11, the photoresist film is patterned by a so-called photolithography method. Thus, in the first embodiment, a plurality of recesses 15a extending in the width direction (vertical direction in the upper drawing of FIG. 3) are formed in the region corresponding to the polarization inversion portion to be formed on the ferroelectric substrate 11 in the photoresist film. The pattern is formed on the resist layer 15.

  Next, a chromium film 16 is formed on the patterned resist layer 15 by sputtering (or vapor deposition). Thereby, a part of the chromium film 16 enters the recess 15a and is located on the other main surface S2A of the ferroelectric substrate 11. Further, a gold film 17 is formed on the entire surface of the chromium film 16 by sputtering (or vapor deposition) (FIG. 3B). Thus, the gold film 17 is electrically connected to the region of the ferroelectric substrate 11 where polarization inversion is planned via the chromium film 16. Thus, the region where the gold film 17 is electrically connected to the ferroelectric substrate 11 via the chromium film 16 is periodically patterned by the resist layer 15, and the chromium film 16 and the gold film 17 are “ It functions as a “pattern electrode”. Further, a protective resist layer 18 is applied to the portion (ferroelectric substrate 11, resist layer 15 and gold film 17) exposed on the other main surface S2A side of the ferroelectric substrate 11 (FIG. 3C). .

  Subsequently, the region of the ferroelectric substrate 11 corresponding to the concave portion 15a of the resist layer 15 is inverted by a so-called voltage application method. In this embodiment, the probes PB1 and PB2 are bonded to the gold film 17 on the ferroelectric substrate 11 and bonded to each other in a state where the structure 10 shown in FIG. 3C is immersed in the processing container TB in which silicon oil is stored. By electrically connecting to the gold film 13c of the part 13 and applying a high voltage between the probes PB1 and PB2 by the high-voltage power supply PS, the pattern electrode (the chromium film 16 and the gold film 17) is connected between the joint part 13 Then, an electric field is generated to form periodic domain-inverted portions 11b in the ferroelectric crystal of the ferroelectric substrate 11 (FIG. 4). Thus, a periodically poled structure is formed on the ferroelectric substrate 11. After the formation of the periodically poled structure, the optical device 1A is taken out from the processing container TB, and the resist layer 15, the chromium film 16, the gold film 17, and the protective resist layer 18 are removed from the other main surface S2A of the ferroelectric substrate 11. Remove. Thus, the optical device 1A shown in FIG. 1 is obtained.

  As described above, according to the first embodiment of the present invention, the one main surface S1A of the ferroelectric substrate 11 constituted by the unipolarized ferroelectric crystal and the support thicker than the ferroelectric substrate 11 are supported. The ferroelectric substrate 11 is integrated while being supported by the support substrate 14 with the insulating layer 12 and the bonding portion 13 interposed between the main surface S1B of the substrate 14 and, therefore, the ferroelectric material is obtained by the above-described planar polishing process. Even if the substrate 11, that is, the ferroelectric crystal is thinned, the ferroelectric crystal can be firmly supported and fixed. Therefore, in the first embodiment, the ferroelectric crystal can be thinned to a thickness of about 0.1 μm to 200 μm.

  Further, the first metal layer (chrome film 13a + gold film 13b) formed on the one main surface S1A of the ferroelectric substrate 11 and the second metal layer (gold film 13c +) formed on the one main surface S2A of the support substrate 14 are used. Since the joining portion 13 is produced by joining the chromium film 13d), the ferroelectric substrate 11 and the support substrate 14 can be firmly joined and integrated.

  In addition, since the insulating layer 12 is interposed between the one main surface S1A of the ferroelectric substrate 11 and the joint portion 13, a polarization inversion structure can be reliably produced by a voltage application method as shown in FIG. Can do. That is, the ferroelectric substrate 11 composed of a single crystal substrate of MgO: LN or MgO: SLT is highly resistant to optical damage due to MgO doping, but when a voltage is applied, it is a dielectric. A slight leak current is generated, and the polarization inversion portion 11b cannot be formed by the voltage application method. Therefore, the provision of the insulating layer 12 suppresses the generation of a leakage current and ensures the formation of the polarization inversion portion 11b on the ferroelectric substrate 11.

  Furthermore, in the first embodiment, since the periodic polarization reversal structure is formed by the voltage application method after the ferroelectric substrate 11 is thinned, the polarization reversal period can be shortened, and high definition and high accuracy can be achieved. A polarization inversion structure can be obtained. This is because when the periodic domain-inverted structure is manufactured by a voltage application method, the depth of polarization that can be manufactured with respect to the period of polarization is determined. That is, if the polarization inversion period is A and the depth is d, the ratio d / A can be processed within the range up to 50, and the smaller the ratio, the higher the accuracy of processing. Further, if the thickness of the ferroelectric crystal is 150 μm or more, the mechanical strength of the ferroelectric crystal is sufficiently maintained, while the electrode provided on the main surface S1A side (in the above embodiment, the “joining portion 13” is provided). Voltage) to the electrode provided on the other main surface S2A side (corresponding to the pattern electrodes (chrome film 16 and gold film 17) in the above embodiment) can be applied without difficulty, and the period A is about 3 μm. The periodic polarization inversion is possible. Therefore, with the progress of thinning of the ferroelectric substrate 11, the polarization inversion period can be further shortened from the above-described relationship between the period and the depth, and the processing accuracy can be improved. It should be noted that an excellent specific effect can be obtained by applying the optical device 1A having such characteristics to an optical modulator or a wavelength conversion element. These points will be described in detail later in the sections “Optical modulator using optical device” and “Wavelength conversion element using optical device”.

  Thus, in the first embodiment, the arrangement pattern of the recesses 15a formed in the resist layer 15 corresponds to the “periodic pattern” of the present invention. The insulating layer 12 corresponds to the “first insulating layer” of the present invention.

Second Embodiment
FIG. 5 is a cross-sectional view showing a second embodiment of the optical device according to the present invention. FIG. 5 (a) is a diagram showing the overall configuration, and FIG. 5 (b) is a broken line portion of FIG. It is an enlarged schematic diagram. FIG. 6 is a schematic diagram showing a manufacturing method of the optical device shown in FIG. 5, and shows only a characteristic manufacturing process in the second embodiment. The second embodiment is greatly different from the first embodiment in the configuration of the joint portion 13, and other configurations are the same as those in the first embodiment. Accordingly, the same reference numerals are assigned to the same components, and descriptions thereof are omitted.

  In the second embodiment, the chromium film 13a and the gold film 13b constituting the first metal layer are patterned into the arrangement pattern of the recesses 15a formed in the resist layer 15, that is, the formation pattern of the polarization inversion parts 11b. On the other hand, the gold film 13c and the chromium film 13d constituting the second metal layer are patterned in the same manner as the first metal layer except for the area where the chip CA is not stacked on the chip CB (the right area in FIGS. 5 and 6). ing. And as shown in FIG.5 (b), both metal layers are joined and the junction part 13 is formed so that patterned gold film 13b, 13c may become a pair. Hereinafter, the manufacturing method of the optical device 1B of FIG. 5 will be described with reference to FIG. The size of the joint portion 13 in FIG. 6 is significantly different from that in FIG. 5. This is because the structure of the joint portion 13 is different from that of the optical device 1B in FIG. 5 in order to clarify the manufacturing method of the optical device 1B. This is because it is enlarged compared to the configuration, and is essentially the same as the configuration of FIG.

  In the second embodiment, as in the first embodiment, the insulating layer 12, the chromium film 13a, and the gold film 13b are formed on the one main surface S1A of the ferroelectric substrate 11 on the chip CA side, and the chip CB. On the side, a chromium film 13d and a gold film 13c are formed on one main surface S1B of the support substrate 14. Then, a positive pattern is formed by photolithography so as to match the pattern of the domain-inverted portion 11b, the chromium film 13a and the gold film 13b of the chip CA are formed, and the chromium film 13d and the gold film are formed on the one main surface S1B of the chip CB. A film 13c is formed (FIG. 6A). Of the chromium film 13d and the gold film 13c on at least the chip CB side, a patterned patterning region (a left-hand side region in FIG. 5A) and a non-patterning region that remains in a film state without being patterned ( 5 (a) is electrically connected to the non-patterning region as will be described later, and is configured to have the same potential in the patterning region when a predetermined potential is applied to the non-patterning region. Has been.

  Then, after irradiating the patterned gold films 13b and 13c with an argon fast atom beam to activate the chip surface, the chip CA is turned upside down, and the gold films 13b and 13c having the same pattern are brought into close contact with each other. Then, the chip CA is laminated on the chip CB and bonded (FIG. 6B). By this FAB bonding, a joint portion 13 having a four-layer structure is formed, and the chips CA and CB are integrated.

  Subsequently, similarly to the first embodiment, after performing a thinning process by planar polishing and an edge removal process of the chip CA, a patterned resist layer 15, a chromium film 16 and a gold film 17 are formed to form a pattern. An electrode is formed. Further, a protective resist layer 18 is applied. Then, as shown in FIG. 5C, the structure P thus formed is immersed in the processing container TB in which silicon oil is stored, and the probes PB1 and PB2 are placed on the ferroelectric substrate 11, respectively. A pattern electrode (chrome film 16 and gold film 17) and a joint are electrically connected to the non-patterning regions of the gold film 17 and the gold film 13c, and a voltage is applied between the probes PB1 and PB2 by the high-voltage power supply PS. An electric field is generated between the 13 patterning regions to form periodic polarization inversion portions 11 b in the ferroelectric crystal of the ferroelectric substrate 11.

  As described above, also in the optical device 1B of the second embodiment, as in the first embodiment, the one main surface S1A of the ferroelectric substrate 11 and the one main surface of the support substrate 14 thicker than the ferroelectric substrate 11 are used. Since the ferroelectric substrate 11 is integrated while being supported by the support substrate 14 with the patterned junction 13 interposed between the surface S1B, the ferroelectric substrate 11, that is, the ferroelectric, is obtained by the above-described planar polishing process. The body crystal can be thinned. Moreover, since the junction part 13 is patterned in the pattern of the polarization inversion part 11b, the following effect is obtained. That is, when a voltage is applied, the lines of electric force act straight on the ferroelectric crystal of the ferroelectric substrate 11 to form a favorable domain-inverted structure.

  In the first embodiment and the second embodiment, the insulating layer 12 is formed on the one principal surface S1A of the ferroelectric substrate 11, but the ferroelectric constituting the optical device shown in FIGS. A so-called step index type waveguide may be formed by forming an insulating layer on the other main surface S2A of the substrate 11 and sandwiching the ferroelectric substrate 11 between these two insulating layers. As a result, light can be propagated while confined in the waveguide, so that loss of light in the ferroelectric substrate 11 can be reduced. Further, a proton exchange waveguide may be provided in a part in the thickness direction from the other main surface S2A to the one main surface S1A of the ferroelectric substrate 11, so that light is confined and propagated in the waveguide. Similarly to the above, the loss of light in the ferroelectric substrate 11 can be reduced.

  In the first and second embodiments, the optical devices 1A and 1B are configured using the ferroelectric substrate 11 formed of a single crystal substrate of MgO: LN or MgO: SLT. The ferroelectric substrate 11 may be composed of lithium tantalate (MgO) added with magnesium (MgO) or stoichiometric lithium niobate (MgO) added with magnesium oxide (MgO). .

  In addition, Lithium Tantalate, Stoichiometric Lithium Tantalate, Lithium Niobate, Stoichiometric Lithium Niobate (Stoichiometric Lithium) without addition of magnesium oxide (MgO) The ferroelectric substrate 11 may be made of Niobate. In addition, a proton exchange waveguide is formed in at least one of the vicinity of the surface of the one main surface S1A and the surface of the other main surface S2A of the ferroelectric substrate 11 so that the light in the ferroelectric substrate 11 is transmitted. Loss may be reduced. However, in these embodiments, since MgO is not added, no leakage current is generated even when a high voltage is applied during the formation of the domain-inverted structure, so that the formation of the insulating layer 12 is unnecessary. Other configurations and manufacturing methods are the same.

<Third Embodiment>
FIG. 7 is a cross-sectional view showing a third embodiment of the optical device according to the present invention. The optical device 1C according to the third embodiment includes a ferroelectric substrate 11 made of a ferroelectric crystal having a periodically poled structure, and a ferroelectric substrate 11 as shown in FIG. A thick support substrate 14 is joined and integrated through a joint portion 13 having a four-layer structure, and is manufactured as follows.

  In the third embodiment, a ferroelectric substrate 11 and a support substrate 14 made of a ferroelectric crystal having a periodically poled structure are prepared. In the third embodiment, as in the first and second embodiments, the support substrate 14 has the same composition as the ferroelectric substrate 11 and the absolute value of the crystal orientation is the same as that of the ferroelectric substrate 11. It consists of a ferroelectric crystal. Then, a chromium film 13a and a gold film 13b are laminated in this order on one main surface S1A of the ferroelectric substrate 11 by sputtering treatment or vapor deposition treatment to form a first metal layer and one main surface of the support substrate 14 A chromium film 13d and a gold film 13c are laminated in this order on S1B to form a second metal layer (FIG. 7A).

  The chip surfaces are activated by irradiating the gold films 13b and 13c with an argon fast atom beam. Further, the chip CA composed of the ferroelectric substrate 11 and the first metal layer is turned upside down, and then the chip CA is stacked and bonded on the chip CB composed of the support substrate 14 and the second metal layer (FIG. 7). (B)). By this FAB bonding, a joint portion 13 having a four-layer structure is formed, and the chips CA and CB are integrated. Note that in the third embodiment, the chips CA and CB are overlapped so as to exactly match.

  The other main surface of the chip CA integrated with the chip CB, that is, the other main surface S2A of the ferroelectric substrate 11 is planarly polished so that the ferroelectric substrate 11 has a desired thickness (thickness of 0.1 μm to 200 μm). A thin film is formed (FIG. 7C). Further, a proton exchange waveguide 19 is provided in a part of the ferroelectric substrate 11 in the thickness direction from the other main surface S2A to the one main surface S1A, and the ferroelectric substrate 11 is held while confining light in the waveguide 19. The light loss is reduced by propagation. The optical device 1C thus manufactured is the third embodiment of the present invention.

  As described above, also in the third embodiment, the one main surface S1A of the ferroelectric substrate 11 and the one main surface S1B of the support substrate 14 thicker than the ferroelectric substrate 11 are the same as in the first embodiment. Since the ferroelectric substrate 11 is integrated while being supported by the support substrate 14 with the joint portion 13 interposed therebetween, the ferroelectric substrate 11, that is, the ferroelectric crystal is thinned by the above-described planar polishing process. Can do.

<Fourth embodiment>
FIG. 8 is a sectional view showing a fourth embodiment of the optical device according to the present invention. The optical device 1D according to the fourth embodiment is largely different from the third embodiment in the form of a waveguide. That is, in the fourth embodiment, a step index type waveguide is formed by sandwiching a ferroelectric substrate 11 composed of a ferroelectric crystal having a periodically poled structure with an insulating layer such as SiO ₂ . Other configurations and operational effects are the same as those of the third embodiment. Hereinafter, the manufacturing method of the optical device 1D will be described with reference to FIG.

In the fourth embodiment, a ferroelectric substrate 11 and a support substrate 14 made of a ferroelectric crystal having a periodically poled structure are prepared. In the ferroelectric substrate 11, after the SiO ₂ insulating layer 12a is formed on the one main surface S1A by sputtering, the chromium film 13a and the gold film 13b are formed in this order on the insulating layer 12a by sputtering or vapor deposition. To form a first metal layer. On the other hand, in the support substrate 14, a second metal layer in which a chromium film 13d and a gold film 13c are laminated is formed on the one main surface S1B of the support substrate 14 as in the third embodiment (FIG. 8A). )).

  Then, as in the third embodiment, the gold films 13b and 13c are irradiated with an argon fast atom beam to activate the chip surface, and further the chip CA comprising the ferroelectric substrate 11, the insulating layer 12a and the first metal layer. Then, the chip CA is stacked and bonded on the chip CB formed of the support substrate 14 and the second metal layer (FIG. 8B). By this FAB bonding, a joint portion 13 having a four-layer structure is formed, and the chips CA and CB are integrated.

Following this, the other main surface S2A of the ferroelectric substrate 11 is planarly polished to reduce the thickness of the ferroelectric substrate 11 to a desired thickness (thickness of 0.1 μm to 200 μm) (FIG. 8C). Further, a SiO ₂ insulating layer 12b is deposited on the other main surface S2A of the polished ferroelectric substrate 11 by sputtering to form a step index type waveguide (FIG. 8D). The optical device 1D thus manufactured is the fourth embodiment of the present invention.

<Fifth Embodiment>
FIG. 9 is a sectional view showing a fifth embodiment of the optical device according to the invention. The optical device 1E according to the fifth embodiment is greatly different from the fourth embodiment in the form of a waveguide. In other words, in the fifth embodiment, before joining the ferroelectric substrate 11 and the support substrate 14, a proton exchange waveguide is formed in a part in the thickness direction from the other main surface S 2 A to the one main surface S 1 A of the ferroelectric substrate 11. 19 is formed so that the proton exchange waveguide 19 remains on the ferroelectric substrate 11 even after the ferroelectric substrate 11 is thinned by the planar polishing after the bonding. Other configurations and operational effects are the same as those of the third embodiment and the fourth embodiment. Hereinafter, the manufacturing method of the optical device 1E will be described with reference to FIG.

  In this fifth embodiment, a ferroelectric substrate 11 and a support substrate 14 each having a periodic polarization reversal structure and composed of a ferroelectric crystal having a proton exchange waveguide 19 provided in the vicinity of at least one main surface S1A are provided. prepare. In the same manner as in the fourth embodiment, the first metal layer is formed by laminating the insulating layer 12a, the chromium film 13a, and the gold film 13b in this order on the one main surface S1A of the ferroelectric substrate 11. Then, a second metal layer is formed by laminating the chromium film 13d and the gold film 13c on the one main surface S1B of the support substrate 14 (FIG. 9A).

  Then, as in the above embodiment, the gold film 13b, 13c is irradiated with an argon fast atom beam to activate the chip surface, and a chip CA comprising the ferroelectric substrate 11, the insulating layer 12a, and the first metal layer is formed. After turning upside down, the chip CA is stacked and bonded on the chip CB formed of the support substrate 14 and the second metal layer (FIG. 9B). By this FAB bonding, a joint portion 13 having a four-layer structure is formed, and the chips CA and CB are integrated. Subsequently, the other main surface S2A of the ferroelectric substrate 11 is planarly polished to reduce the thickness of the ferroelectric substrate 11 to a desired thickness (thickness of 0.1 μm to 200 μm) (FIG. 9C). The optical device 1E thus manufactured is the fifth embodiment of the present invention.

<Optical modulator using optical device>
Since the optical device according to the present invention has the above-described features, excellent effects can be obtained by applying the optical device to an optical modulator. Therefore, for example, the configuration and operation of the optical modulator to which the optical device 1A of FIG. 1 is applied will be described through the description of the configuration of the exposure apparatus and pattern drawing apparatus equipped with the optical modulator.

  FIG. 10 is a perspective view showing a pattern drawing apparatus equipped with an optical modulator to which an optical device according to the present invention is applied, FIG. 11 is a side view of the pattern drawing apparatus shown in FIG. 10, and FIG. It is a block diagram which shows the electric constitution of a pattern drawing apparatus. The pattern drawing apparatus 100 is an apparatus that draws a pattern by irradiating light onto the surface of a substrate W such as a semiconductor substrate or a glass substrate to which a photosensitive material is applied.

  In this pattern drawing apparatus 100, each part of the apparatus is arranged inside a main body formed by attaching a cover 102 to the main body frame 101 to constitute the main body, and the outside of the main body (in the present embodiment, FIG. As shown in FIG. 11, a substrate storage cassette 110 is disposed on the right hand side of the main body. The substrate storage cassette 110 stores an unprocessed substrate W to be subjected to exposure processing, and is loaded into the main body by a transfer robot 120 disposed inside the main body. Further, after the exposure process (pattern drawing process) is performed on the unprocessed substrate W, the substrate W is unloaded from the main body by the transfer robot 120 and returned to the substrate storage cassette 110.

  In this main body, as shown in FIGS. 10 and 11, the transfer robot 120 is disposed at the right hand end inside the main body surrounded by the cover 102. A base 130 is disposed on the left hand side of the transfer robot 120. One end side region (the right hand side region in FIGS. 10 and 11) of the base 130 is a substrate delivery region for delivering the substrate W to and from the transfer robot 120, while the other end side region. (Left-hand side region in FIGS. 10 and 11) is a pattern drawing region for pattern drawing on the substrate W. On the base 130, a head support 140 is provided at the boundary position between the substrate delivery area and the pattern drawing area. In the head support portion 140, two leg members 141 and 142 are erected upward from the base 130, and a beam member 143 is laterally provided so as to bridge the top portions of the leg members 141 and 142. Yes. Then, as shown in FIG. 11, the camera (imaging unit) 150 is fixed to the side of the pattern drawing area of the beam member 143 and the surface of the substrate W (the drawing surface and the exposed surface) held on the stage 160 is imaged. It is possible.

  The stage 160 is moved on the base 130 by the stage moving mechanism 161 in the X direction, the Y direction, and the θ direction. That is, the stage moving mechanism 161 has a Y-axis drive unit 161Y (FIG. 12), an X-axis drive unit 161X (FIG. 12), and a θ-axis drive unit 161T (FIG. 12) stacked on the upper surface of the base 130 in this order. The stage 160 is moved and positioned two-dimensionally in a horizontal plane. Further, the stage 160 is rotated around the θ axis (vertical axis) to adjust the relative angle with respect to the optical head 3 described later for positioning. As such a stage moving mechanism 161, an XY-θ axis moving mechanism that has been widely used conventionally can be used.

  Further, the optical head 3 is fixedly attached to the box 172 on the pattern drawing region side of the head support portion 140 configured as described above. The optical head 3 is equipped with a spatial light modulator using the optical device 1A according to the present invention and irradiates the substrate W with light, and corresponds to the “exposure apparatus” of the present invention. ing. The configuration and operation will be described in detail later.

  In addition, two leg members 144 are also erected at the opposite end of the base 130 on the side opposite to the board delivery side (the left-hand side end in FIGS. 10 and 11). A box 172 containing the illumination optical system of the optical head 3 is provided so as to bridge the beam members 143 and the tops of the two leg members 144, and covers the pattern drawing region of the base 130 from above. Yes. Therefore, even if the downflow supplied into the clean room in which the pattern drawing apparatus 100 is installed is drawn into the main body, a space SP in which the downflow is not supplied is formed in the pattern drawing area.

  Therefore, in the pattern drawing apparatus 100 according to the present embodiment, the gas blowout that blows the temperature-controlled gas toward the space SP sandwiched between the stage 160 and the box 172 of the optical head 3 on the side opposite to the robot in the space SP. A part 190 is arranged. In this embodiment, the two gas blowing parts 190 are attached up and down so that the cover 102 which comprises the left-hand side wall of a main-body part may be penetrated. These gas blowing units 190 are connected to an air conditioner 191 and operate according to a command from the exposure control unit 181 to blow out the air temperature-controlled by the air conditioner 191 toward the space SP. Thereby, the temperature-controlled gas blown out from the gas blowing unit 190 flows sideways and passes through the space SP. As a result, the atmosphere of the space SP is changed, and the temperature change in the pattern drawing area is suppressed. In addition, the air that has passed through the space SP flows into the transfer robot 120 in this way, but in this embodiment, an exhaust port 192 is provided in the lower portion of the transfer robot 120 and the exhaust port 192 is air-conditioned via the pipe 193. Connected to the device 191. Therefore, by providing the exhaust port 192, the atmosphere surrounding the transfer robot 120 is exhausted, and a downward airflow, that is, a downflow is formed in the atmosphere. Accordingly, it is possible to effectively prevent the particles from rising and scattering by the transfer robot 120.

  Next, the configuration and operation of the optical head (exposure apparatus) 3 will be described. In this embodiment, the optical head 3 is fixedly attached to the box 172, and is held on the stage 160 by reflecting light onto the substrate W moving at a position immediately below the optical head 3. The substrate W is exposed to draw a pattern. In the present embodiment, the optical head 3 can simultaneously irradiate light in a plurality of channels in the X direction, and the X direction corresponds to the “sub-scanning direction”. Further, by moving the stage 160 in the Y direction, a pattern can be drawn two-dimensionally on the substrate W, and the Y direction corresponds to the “main scanning direction”.

  FIG. 13 is a diagram showing the internal configuration of the optical head in a simplified manner. FIG. 13A shows the optical head 3 above the optical head 3 along the optical axis OA and the sub-scanning direction X (that is, in FIG. 10). The (+ Y) side) shows the internal configuration of the optical head 3 when viewed from the (+ Y) side, and FIG. 10B shows the optical head 3 side viewed from the front side (lower left side) of FIG. The internal configuration of the optical head 3 in this case (that is, when viewed from the (−X) side of the optical head 3 toward the (+ X) direction) is shown.

  The optical head 3 shown in FIG. 13 includes a light source unit 31 configured by a semiconductor laser or the like that emits a light beam having a predetermined wavelength (for example, 830, 635, 405, or 355 nanometers (nm)). Yes. When a 355 nm laser beam is used, a solid-state laser light source using a third harmonic of a YAG (Yttrium Aluminum Garnet) laser is used. The light source unit 31 has a collimator lens (not shown), and the light beam emitted from the semiconductor laser is converted into parallel light through the collimator lens and enters the illumination optical system 32 through a mirror (not shown). To do.

  The illumination optical system 32 includes three cylindrical lenses 321 to 323, and the light beam emitted from the light source unit 31 passes through the cylindrical lenses 321 to 323 in this order and enters the spatial light modulator 33. Among these, the cylindrical lens 321 has a beam expanding function (negative condensing function) only in the X direction, and the light passing through the cylindrical lens 321 has a light beam cross section perpendicular to the optical axis OA from a circular shape to gradually in the X direction. It changes to a long oval. On the other hand, with respect to the optical axis OA and the Y direction perpendicular to the X direction, the width of the light beam cross section of the light passing through the cylindrical lens 321 is (almost) constant. Further, the cylindrical lens 322 has a positive condensing function only in the X direction, and the light beam that has passed through the cylindrical lens 321 is shaped by the cylindrical lens 322. In other words, the light that has passed through the cylindrical lens 322 is made into an elliptical shape having a constant cross-section with a long cross section in the X direction, and is incident on the cylindrical lens 323. The cylindrical lens 323 has a positive condensing function only in the Y direction. When attention is paid only to the Y direction, the light LI that has passed through the cylindrical lens 323 is condensed as shown in FIG. However, the light enters the incident surface 331a of the spatial light modulator 33. As for the X direction, as shown in FIG. 13A, the light beam from the cylindrical lens 323 enters the spatial light modulator 33 as a parallel light beam.

  The spatial light modulator 33 includes an optical modulation element 331, an electrode substrate 332, an electric circuit board 336, and an optical modulation element 331 (optical device 1A) configured by the optical device 1A according to the first embodiment of the present invention. A modulation unit 338 (FIG. 12) that modulates light that generates an electric field in the ferroelectric substrate 11 and propagates through the ferroelectric crystal of the ferroelectric substrate 11 is provided.

  14A and 14B are diagrams showing the spatial light modulator. FIG. 14A is a partial sectional view of the spatial light modulator in the YZ plane, and FIG. 14B is a partial sectional view of the spatial light modulator in the XY plane. It is. In this spatial light modulator 33, as shown in FIGS. 13 and 14, a wiring region Ra and a mounting for mounting a light modulating element 331 composed of the optical device 1A on the upper main surface of the electrode substrate 332 are mounted. A placement region Rb is provided. Each of the plurality of electrodes 333 extends in the Z-axis direction from the wiring region Ra to the placement region Rb. More specifically, the (−Z side end) of each electrode 333 extends in the Z direction in the wiring region Ra and reaches the mounting region Rb. In this placement region Rb, the (+ Z side end portion) of each electrode 333 extends substantially parallel to the Z direction. In the present embodiment, a portion of each electrode 333 located on the wiring region Ra, that is, the (−Z side end portion) of each electrode 333 is an inductive coupling to be described later. Part ". Further, a portion located on the mounting region Rb, that is, (+ Z side end portion) of each electrode 333 is opposed to the ferroelectric substrate 11 of the light modulation element 331, and is an electrode for controlling the periodic polarization inversion structure. Since it functions as a part, it is referred to as an “electrode part” below.

A protective film 334 made of an insulating material such as SiO ₂ is formed on the entire upper main surface of the electrode substrate 332 so as to cover these electrodes 333 to protect the electrode 333 and the surface of the protective film 334 (upper main surface). ) Is flattened. In the placement region Rb, the light modulation element 331 is placed on a position corresponding to the placement region Rb. Thus, as shown in FIG. 14, the electrode portion of each electrode 333 is arranged to face the other main surface S2A of the ferroelectric substrate 11 with the protective film 334 interposed therebetween.

  In the light modulation element 331 arranged in this way, the joint portion 13 is formed via the insulating layer 12 so as to cover the entire one main surface S1A of the ferroelectric substrate 11. Since the optical device 1 </ b> A is used as the light modulation element 331, a ground potential is applied to the joint portion 13. On the other hand, for each of the plurality of electrodes 333 described above, a voltage corresponding to light modulation is modulated by inductive coupling via a wiring (not shown) provided on the upper main surface of the electric circuit board 336. It is given from.

  On the upper main surface of the electric circuit board 336, a wiring made of a conductive material having the same shape as the induced pattern portion is a guided pattern portion (a portion of the electrode 333 located on the wiring region Ra). They are formed in a one-to-one correspondence. For this reason, the electrodes facing one another are electrically connected by inductive coupling. In addition, a plurality of electronic components 3381 constituting the modulation unit 338 are mounted on the lower main surface of the electric circuit board 336, and are electrically connected to the electrodes 333 via the electric circuit board 336. As described above, a voltage is applied to the electrode 333 independently according to various signals and data from the exposure control unit 181.

  As shown in FIG. 12, the exposure timing signal, the exposure position signal, and the exposure data are given to the modulation unit 338 from the exposure control unit 181. The modulation section 338 has an analog circuit (not shown) for each electrode 333, that is, for each channel, and applies a drive voltage (V1 or 0V) to the electrode 333 based on the exposure data given from the exposure control section 181. To do. The exposure control unit 181 controls a plurality of electrodes 333 (for example, two or more adjacent electrodes 333) as one channel so as to be longer than the period of the periodically poled structure.

  In the spatial light modulator 33, the junction 13 is grounded, whereas the electrodes 333 constituting each channel are independently supplied from the modulator 338 according to the exposure data from the exposure controller 181 as described above. Receives voltage. For this reason, in the periodic polarization reversal structure of the light modulation element 331, it occurs between the electrode 333 and the junction 13 only in a region corresponding to the electrode 333 to which the predetermined potential V1 (potential other than 0V) is applied from the modulation unit 338. A refractive index change according to the polarization direction is generated by the electric field, and a diffraction grating is formed. As a result, diffracted light DL is generated in the channel. On the other hand, in other channels, incident light passes through the light modulation element 331 as it is as 0th-order light L0.

  Returning to FIG. 13, the description of the configuration of the optical head 3 will be continued. An aperture plate 352 having a cylindrical lens 34 having a positive condensing function only in the Y direction, a lens 351, and an aperture 3521 on the emission side (right hand side in FIG. 13) of the spatial light modulator 33 configured as described above. The lenses 353 are arranged in this order. The cylindrical lens 34 has a positive condensing function only in the Y direction, and the zero-order light L0 or the diffracted light DL from the spatial light modulator 33 is applied to the cylindrical lens 34 as shown in FIG. The light is substantially parallel to the Y direction and is incident on a lens 351 having a positive light collecting function.

  Here, the front focal point of the lens 351 is a position in the light modulation element 331 in the vicinity of the end of the electrode 333 on the (+ Z) side, and the aperture plate 352 is disposed so that the aperture 3521 is positioned at the rear focal point of the lens 351. Is done. Accordingly, the zero-order light L0 that is not diffracted in the light modulation element 331, passes through the lens 34, and is substantially parallel to both the X direction and the Y direction is indicated by a thin solid line in FIG. As described above, the light is condensed on the aperture 3521 through the lens 351, passes through the aperture 3521, and enters the lens 353. The lens 353 is arranged so that the front focal point is located in the vicinity of the aperture 3521 and the rear focal point is on the surface of the substrate W held by the stage 160, and the 0th-order light L 0 passes through the lens 353. The surface of the substrate W is irradiated and exposed. On the other hand, the diffracted light DL is emitted from the light modulation element 331 at a predetermined angle with respect to the optical axis OA, as indicated by a broken line in FIG. It is shielded by the surface of the aperture plate 352.

  Thus, in the present embodiment, the so-called Schlieren optical system 35 is configured by the lens 351, the aperture plate 352, and the lens 353. The schlieren optical system 35 has the same arrangement as the double-sided telecentric optical system. As shown in FIG. 13, even when the substrate W is exposed with the optical head 3 having a plurality of channels, the exposure surface (the surface of the substrate W). ), The principal ray of the zero-order light LO of each channel (the two-dot chain line in FIG. 13) is vertical, and is not affected by the change in magnification with respect to the change in the focus direction Z of the exposure surface. As a result, highly accurate exposure is possible. As described above, in the first embodiment, pattern drawing on the substrate W is performed using 0th-order light. Further, the lens 34 and the schlieren optical system 35 arranged as described above function as the “optical system” of the present invention, and the light from the spatial light modulator 33 is transmitted to the surface of the substrate W (exposed surface, drawing surface). Screen).

  The pattern drawing apparatus 100 configured as described above has a computer 200 for controlling the entire apparatus. The computer 200 includes a CPU, a memory 201, and the like, and is arranged in an electrical rack (not shown) together with the exposure control unit 181. In addition, the rasterization unit 202, the expansion / contraction rate calculation unit 203, the data correction unit 204, and the data generation unit 205 are realized by the CPU in the computer 200 performing arithmetic processing according to a predetermined program. For example, pattern data corresponding to one LSI is data generated by an external CAD or the like, and is prepared in advance in the memory 201 as LSI data 211. Based on the LSI data 211, the LSI pattern is as follows. Is drawn on the substrate W.

  The rasterizing unit 202 divides and rasterizes the unit area indicated by the LSI data 211, generates raster data 212, and stores it in the memory 201. Thus, after preparing the raster data 212 or in parallel with the preparation of the raster data 212, the unprocessed substrate W stored in the cassette 110 as described above is unloaded by the transfer robot 120, and the stage is set by the transfer robot 120. 160.

  Thereafter, the stage 160 is moved to a position immediately below the camera 150 by the stage moving mechanism 161, and the alignment marks (reference marks) on the substrate W are sequentially positioned at the imageable positions of the camera 150, and mark imaging by the camera 150 is executed. Is done. The image signal output from the camera 150 is processed by an image processing circuit (not shown in FIG. 12) in the electrical rack, and the position of the alignment mark on the stage 160 is accurately obtained. Then, the θ-axis drive unit 161T operates based on these pieces of position information, and the stage 160 is slightly rotated about the vertical axis to be aligned (positioned) in a direction suitable for pattern drawing on the substrate W. Here, the alignment may be performed after the stage 160 is moved to a position directly below the optical head 3.

  The stretch rate calculation unit 203 illustrated in FIG. 12 acquires the alignment mark position on the substrate W and the correction amount of the orientation of the substrate W obtained by the image processing circuit, the alignment mark position after alignment, and The expansion / contraction ratio of the substrate W with respect to the main scanning direction Y and the sub-scanning direction X (that is, the expansion ratio of the main surface) is obtained.

  On the other hand, the data correction unit 204 acquires the raster data 212 and corrects the data based on the expansion / contraction rate that is the detection result of expansion / contraction. For this data correction, for example, the method described in Japanese Patent No. 40020248 can be adopted. When the data correction of one divided area is completed, the corrected raster data 212 is sent to the data generation unit 205. . The data generation unit 205 generates drawing data corresponding to the changed divided area, that is, data corresponding to one stripe.

  The drawing data generated in this way is sent from the data generation unit 205 to the exposure control unit 181, and the exposure control unit 181 controls each unit of the modulation unit 338, the head moving mechanism 171, and the stage moving mechanism 161, thereby generating one stripe. Is drawn. Note that the exposure operation is performed by the electric field generation control by the modulation unit 338 as described above. When the exposure recording for one stripe is completed, the same processing is performed for the next divided region, and drawing for each stripe is repeated. Thus, when drawing of all the stripes on the substrate W is completed and drawing of a desired pattern on the surface of the substrate W is completed, the stage 160 keeps the drawn substrate W placed on the substrate delivery position (see FIGS. 10 and 11). After moving to the right region), the substrate transport robot 120 returns the substrate W to the cassette 110, the next substrate W is taken out, and the same series of processing as described above is repeated. Further, when the pattern drawing on all the substrates W stored in the cassette 110 is completed, the cassette 110 is unloaded from the pattern drawing apparatus 100.

  As described above, since the above-described pattern drawing apparatus 100 applies the optical device 1A according to the first embodiment as the light modulation element 331 of the light modulator 33 as it is, the following operational effects are obtained. That is, as described above, in the optical device 1A, the periodic polarization reversal structure is thinner than that in the related art, and therefore the distance between the junction 13 and each electrode 333 is also short. Therefore, the drive voltage can be set low and high-speed modulation is possible.

  In the optical head 3 (corresponding to the “exposure apparatus” of the present invention) of the pattern drawing apparatus 100, the optical device 1A according to the first embodiment is applied as it is as the light modulation element 331 of the light modulator 33. Optical devices according to other embodiments may be used as the light modulation element 331.

  In the optical head 3, the optical modulator 33 is configured by disposing the ferroelectric substrate 11 of the optical device 1A so as to face the electrode substrate 332 on which the plurality of electrodes 333 are formed. 15 is applied to an optical modulator, for example, a plurality of electrodes are arranged on the other main surface S2A of the ferroelectric substrate 11 as shown in FIG. 15, and a drive voltage is applied to each electrode from the modulator. Also good.

<Wavelength conversion element using optical device>
Next, an excellent effect can also be obtained by applying the optical device according to the present invention to a wavelength conversion element. Therefore, for example, a wavelength conversion element to which the optical device 1A of FIG.

  FIG. 16 is a diagram showing an example of a wavelength conversion element using the optical device according to the present invention. FIG. 2A is a perspective view showing a wavelength conversion element in which a polarization inversion waveguide is formed in a part of a ferroelectric crystal of a ferroelectric substrate, and FIG. 2B is a ferroelectric substance of the ferroelectric substrate. It is a perspective view which shows the wavelength conversion element which has a slab waveguide which reversed the whole crystal | crystallization, and the figure (c) is a cross section of the waveguide part of the wavelength conversion element shown to the figure (a) and the figure (b). FIG.

  The wavelength conversion elements 400A and 400B shown in FIG. 16 use the optical device 1A according to the first embodiment, and are proton-exchanged in the ferroelectric crystal in the vicinity of the other main surface S2A of the ferroelectric substrate 11. A waveguide 19 is formed. The difference between the wavelength conversion element 400A in FIG. 10A and the wavelength conversion element 400B in FIG. 10B is the formation range of the proton exchange waveguide 19, and FIG. The light L (λin) is incident on the waveguide through the channel waveguide, and FIG. 6B shows a configuration in which the light L (λin) is also incident on the waveguide width widely by a slab waveguide wide in the crystal width direction. . Other configurations are the same. In both 400A and 400B, when light L (λin) having a wavelength λin is incident on one end of the proton exchange waveguide 19, the light propagates in the proton exchange waveguide 19 and has a wavelength different from the wavelength λin. Light L (λout) having λout is emitted from the other end face of the proton exchange waveguide 19.

  In the wavelength conversion elements 400A and 400B configured as described above, the following operational effects can be obtained. In other words, as described above, in the optical device 1A, the polarization inversion portion 11b is formed by the voltage application method on the thinned ferroelectric substrate 11, so that the ferroelectric substrate 11 composed of ferroelectric crystals is formed. In addition, the periodically poled structure can be formed with high accuracy. Further, since the period of the polarization inversion portion 11b can be made shorter than that of the prior art by making the film thinner, the conversion wavelength can be made shorter than that of the prior art, and the periodic polarization inversion structure can be formed with high accuracy, Efficiency can also be improved. Therefore, it is also possible to produce a wavelength conversion element that has been conventionally required and has a high conversion efficiency and corresponds to the ultraviolet wavelength.

  For example, as an ultraviolet light source of the pattern drawing apparatus 100, conventionally, only a large gas laser or solid-state laser could be realized, but by combining the wavelength conversion elements 400A and 400B described above with a small high-power light source such as a semiconductor laser, A small wavelength conversion type ultraviolet light source can be obtained. In addition, since the wavelength conversion efficiency is improved by increasing the accuracy of the domain-inverted structure, the wavelength conversion type ultraviolet light source can be applied not only to industrial use but also to medical use, and its use is expected to expand.

In the wavelength conversion elements 400A and 400B, the proton exchange waveguide 19 is formed in the ferroelectric crystal of the optical device 1A. For example, as shown in FIG. 17, the other main surface of the ferroelectric substrate 11 is used. the insulating layer 12b, such as SiO ₂ is formed on S2A, step-index waveguide formed by the wavelength conversion element 400C, 400D, it affords the wavelength conversion element 400A, the same effect as 400B. In particular, in FIG. 5A, a groove of about several μm is formed by cutting the waveguide width direction with a diamond cutter or the like to confine light.

  Moreover, in the said embodiment, although 1 A of optical devices are applied to a wavelength conversion element, it cannot be overemphasized that another optical device is applicable to a wavelength conversion element, and the same effect is obtained.

<Others>
The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, the patterned joint 13 is used only in the second embodiment, but in the optical devices 1C to 1E according to the third to fifth embodiments, the joint 13 is the same as in the second embodiment. Patterned joints may be employed.

  In the above embodiment, since it is difficult to stably attach gold (Au) to the ferroelectric substrate 11, a chromium film is interposed as an intermediate layer between the two. In addition to chromium (Cr), titanium (Ti) or tantalum (Ta) can be used.

Further, in the above embodiment, the SiO ₂ as the insulating layer may be a transparent dielectric film such as nitrogen oxide film _(SiO x _{N y)} or aluminum oxide _(Al 2 _{O 3).}

  The present invention can be applied to an optical device having a periodically poled structure, a method for manufacturing the optical device, and an exposure apparatus that uses the optical device.

1A to 1E Optical device 3 Optical head (exposure apparatus)
DESCRIPTION OF SYMBOLS 11 ... Ferroelectric substrate 12, 12a, 12b ... Insulating layer 13 ... Junction part 13a ... Chromium film (1st metal layer)
13b ... Gold film (first metal layer)
13c ... Gold film (second metal layer)
13d ... Chromium film (second metal layer)
14 ... support substrate 16 ... chrome film (pattern electrode)
17 ... Gold film (pattern electrode)
DESCRIPTION OF SYMBOLS 19 ... Proton exchange waveguide 33 ... Spatial light modulator 331 ... Light modulation element 338 ... Modulator S1A ... (One side of ferroelectric substrate) S1B ... (One side of support substrate) S2A ... (Ferroelectric substrate) The other main surface

Claims (12)

A ferroelectric substrate composed of a ferroelectric crystal having a periodic polarization reversal structure periodically polarized in a first polarization direction and a second polarization direction opposite to the first polarization direction;
A support substrate;
It is sandwiched between one main surface of the ferroelectric substrate and one main surface of the support substrate facing the one main surface of the ferroelectric substrate, and is integrated while being supported by the support substrate. A joint to be made,
With
The joint is the strong dielectric one first metal layer formed on the main surface of the substrate, the one conductive layer and the second metal layer is bonded which is formed on the main surface of the supporting substrate And
An optical device, wherein the first metal layer and the second metal layer are formed with a pattern that coincides with a period of a portion polarized in the first polarization direction in the periodically poled structure. A ferroelectric substrate composed of a ferroelectric crystal having a periodic polarization reversal structure periodically polarized in a first polarization direction and a second polarization direction opposite to the first polarization direction;
A support substrate;
An insulating layer formed on one main surface of the ferroelectric substrate;
It is sandwiched between the insulating layer and one main surface of the support substrate facing the one main surface of the insulating layer, and the ferroelectric substrate is integrated while being supported by the support substrate via the insulating layer. A junction,
With
The joint, the first metal layer formed on one main surface of the insulating layer, a second metal layer formed on one main surface of the supporting substrate is a conductive layer which is joined,
An optical device, wherein the first metal layer and the second metal layer are formed with a pattern that coincides with a period of a portion polarized in the first polarization direction in the periodically poled structure. The optical device according to claim 1 or 2 ,
The optical device, wherein the support substrate is made of the same crystal as the ferroelectric crystal of the ferroelectric substrate. The optical device according to claim 3 ,
An optical device, wherein an absolute value of a crystal orientation of a crystal constituting the support substrate coincides with an absolute value of a crystal orientation of a ferroelectric crystal of the ferroelectric substrate. An optical device according to any one of claims 1 to 4 ,
The support substrate is thicker than the ferroelectric substrate,
The ferroelectric crystal of the ferroelectric substrate has a thickness of 0.1 μm to 200 μm.
An optical device that is μm. An optical device according to any one of claims 1 to 5 ,
A plurality of electrodes formed on the other principal surface of the ferroelectric substrate;
An optical device, wherein when an electric field is generated between the plurality of electrodes and the junction, diffraction efficiency in the periodically poled structure is modulated. While supporting the ferroelectric substrate with the support substrate by interposing a conductive joint between one main surface of the ferroelectric substrate composed of the ferroelectric crystal and one main surface of the support substrate A first step of integration;
A second step of forming a pattern electrode having a periodic pattern on the other main surface of the ferroelectric substrate;
A third step of periodically forming a polarization inversion portion on the ferroelectric substrate by applying a voltage between the pattern electrode and the junction,
The first step includes a first metal layer forming step of forming a first metal layer having a pattern corresponding to the periodic pattern on one main surface of the ferroelectric substrate;
A second metal layer forming step of forming a second metal layer having a pattern corresponding to the periodic pattern on one main surface of the support substrate;
The convex portion of the pattern of the first metal layer and the convex portion of the second metal layer are joined to form the joint portion, so that the ferroelectric substrate is supported by the support substrate and integrated. Integration process,
A method for manufacturing an optical device. While supporting the ferroelectric substrate with the support substrate by interposing a conductive joint between one main surface of the ferroelectric substrate composed of the ferroelectric crystal and one main surface of the support substrate A first step of integration;
A second step of forming a pattern electrode having a periodic pattern on the other main surface of the ferroelectric substrate;
A third step of periodically forming a polarization inversion portion on the ferroelectric substrate by applying a voltage between the pattern electrode and the junction,
The first step includes forming an insulating layer on one main surface of the ferroelectric substrate, and forming a first metal layer having a pattern corresponding to the periodic pattern on one main surface of the insulating layer. A first metal layer forming step,
A second metal layer forming step of forming a second metal layer having a pattern corresponding to the periodic pattern on one main surface of the support substrate;
The convex portion of the pattern of the first metal layer and the convex portion of the second metal layer are joined to form the joint, thereby supporting the ferroelectric substrate via the insulating layer. An integration process that integrates while supporting the substrate,
A method for manufacturing an optical device. A method of manufacturing an optical device according to claim 7 or claim 8 ,
The integration step includes an activation step of activating the convex portion of the pattern of the first metal layer and the convex portion of the second metal layer by irradiating an argon fast atom beam. Manufacturing method. A method of producing an optical device according to any one of claims 7 to 9,
The support substrate is composed of the same crystal as the ferroelectric crystal of the ferroelectric substrate,
In the integration step, the first metal layer and the second metal layer are joined while the absolute values of the crystal orientations of the support substrate and the ferroelectric substrate coincide with each other. . A method of producing an optical device according to any one of claims 7 to 10,
The surface region on the other main surface side of the ferroelectric substrate integrated with the support substrate is removed to make the thickness of the ferroelectric crystal 0.1 μm to 200 μm.
The manufacturing method of an optical device further provided with the 4th process adjusted to micrometer. In an exposure apparatus that irradiates a surface to be exposed by an optical system with modulated light obtained by modulating light emitted from a light source with an optical modulator,
The light modulator is
An optical device according to any one of claims 1 to 5 ,
A plurality of electrodes disposed on the other principal surface side of the ferroelectric substrate;
An exposure apparatus comprising: a modulation unit that modulates diffraction efficiency in the ferroelectric substrate by controlling electric field generation between the plurality of electrodes and the junction.

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