WO2016132816A1 - Method for producing optical device - Google Patents

Method for producing optical device Download PDF

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Publication number
WO2016132816A1
WO2016132816A1 PCT/JP2016/051846 JP2016051846W WO2016132816A1 WO 2016132816 A1 WO2016132816 A1 WO 2016132816A1 JP 2016051846 W JP2016051846 W JP 2016051846W WO 2016132816 A1 WO2016132816 A1 WO 2016132816A1
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WIPO (PCT)
Prior art keywords
layer
mask
pattern
resin layer
material layer
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PCT/JP2016/051846
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French (fr)
Japanese (ja)
Inventor
浅井　圭一郎
山口　省一郎
近藤　順悟
富田　俊弘
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日本碍子株式会社
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Publication of WO2016132816A1 publication Critical patent/WO2016132816A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
    • B29C59/02—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/027—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34

Definitions

  • the present invention relates to a method for manufacturing an optical device such as a grating element.
  • a resin layer is formed on a semiconductor layer on which the diffraction grating is to be formed. Then, a mold having a concavo-convex pattern corresponding to the shape of the diffraction grating is pressed against the resin layer, and the resin layer is cured in this state. Thereby, the uneven
  • Patent Document 1 describes a method of manufacturing a distributed feedback semiconductor laser using a nanoimprint method. In this method, patterning of a semiconductor layer for a diffraction grating of a distributed feedback semiconductor laser is performed by a nanoimprint method.
  • Non-Patent Documents 1 and 2 describe the production of a subwavelength structured broadband wave plate using nanoimprint technology.
  • Non-Patent Document 3 describes that nanoimprint technology is applied to produce an optical device.
  • optical devices include a wavelength selection element, a reflection control element, and a moth-eye structure.
  • An object of the present invention is to provide a method for improving the transfer accuracy of a fine pattern even when a transfer region is small when forming a fine structure in an optical material layer by an imprint method.
  • the present invention provides a support substrate, An optical element layer provided on a support substrate, and a method of manufacturing an optical device having a fine pattern formed on the optical element layer in a transfer region,
  • a design pattern is formed on the first resin layer by an imprint method using a mold having a design pattern corresponding to a fine pattern.
  • the optical element layer having the fine pattern is formed by forming a second resin layer and then etching the optical material layer through the mask portion.
  • an optical material layer 2, a mask material layer 3, and a first resin layer 4 are formed on a support substrate 1, and a processing assembly 40 is obtained.
  • a mold 47 on which a predetermined fine pattern is formed is brought into contact with the first resin layer to transfer the fine pattern.
  • 47 a is a protrusion of the mold 47
  • 6 is a resin filled in the recess of the mold 47.
  • Reference numeral 5 denotes a compressed resin layer.
  • the mask layer 8 is provided with a convex portion 9 corresponding to a desired fine pattern.
  • this convex portion 9 is also deformed as viewed from the desired shape.
  • an optical element layer 10 having a fine structure composed of convex portions 11 is formed.
  • the shape and pitch of each convex part 11 deviate from the desired shape and desired pitch.
  • the present inventor first tried to transfer the fine pattern 30 of the mold 7 to the resin layer 15 over the region A having a dimension larger than the desired transfer region.
  • the fine pattern is hardly deformed due to the small amount of the resin filling as described above.
  • the mask pattern layer 18 is formed only in the partial area B included in the area A as shown in FIG. It was conceived that the second resin layer 21 was covered.
  • the mask pattern layer 18 is divided into a mask portion 32 covered with the second resin layer 21 and a non-mask portion 33 that is not covered.
  • the second resin layer 21 is removed to expose the mask portion 32, and etching is performed.
  • Structure 34 may be formed in the optical material layer.
  • FIG. 1 and 2 show a reference form.
  • A is a schematic diagram which shows the assembly which should be processed, (b) shows the state which has transferred the fine pattern of the mold 47 to the resin layer, (c) shows the fine pattern on the resin layer 5 The transferred state is shown.
  • A) shows the state in which the mask layer 8 is formed, and (b) shows the optical element layer 10 to which the fine pattern has been transferred.
  • A) shows the state where the fine pattern of the mold 7 has been transferred to the resin layer 15, (b) shows the resin layer to which the fine pattern has been transferred, and (c) shows the mask pattern layer 18.
  • FIG. 6 shows a state in which the mask portion 18 and the second resin layer 21 are left on the optical material layer 2, and (b) shows a state in which the mask portion 18 is exposed by removing the resin layer 21.
  • C shows a state in which the fine pattern 36 is formed by etching the optical material layer.
  • FIG. 3 to 5 relate to the first embodiment.
  • an assembly 40 including a support substrate 1, an optical material layer 2, a mask material layer 3, and a resin layer 4 is prepared.
  • the mold 7 on which the fine pattern 30 is formed over the predetermined area A is brought into contact with the resin layer 4 to form the resin layer 15 to which the fine pattern is transferred.
  • 7a is a protrusion.
  • the fine pattern 31 is composed of a large number of protrusions 15a formed at a constant period, and a recess 16 is formed between adjacent protrusions.
  • the fine pattern 30 is transferred over the predetermined area A that includes the final transfer area B and has a dimension larger than that of the transfer area B. Accordingly, since the size of the predetermined area A is relatively large, it is possible to maintain high transfer accuracy of the fine pattern.
  • the mask pattern layer 18 is formed by etching the resin layer 15 and the underlying mask material layer 3 (FIG. 3C). Concave portions 19 are formed in the mask pattern layer 18 at regular intervals. If necessary, the remaining resin layer 15 is removed (ashing).
  • Reference numeral 20a denotes a flat portion
  • reference numeral 20b denotes a resin filled in the recesses of the mask pattern layer 18.
  • the resin layer 20 is exposed by photolithography to leave the second resin layer 21 as shown in FIG. 21a is a flat part, 21b is a filling part to a recessed part.
  • the resin layer 21 covers the mask pattern layer 18 in the final transfer region B, but the rest of the mask pattern layer 18 is not covered by the resin layer 21.
  • the mask pattern layer 18 is divided into a mask portion 32 covered with the resin layer 21 and a non-mask portion 33 not covered with the resin layer 21.
  • a protective layer 22 covering the mask pattern layer 18 and the resin layer 21 is formed.
  • the resin layer 21 is removed by a lift-off method, and a protective layer 23 is formed as shown in FIG.
  • the opening 24 is formed in accordance with the final transfer region B.
  • the mask portion 32 of the mask pattern layer 18 is exposed in the opening 24.
  • the non-mask portion 33 of the mask pattern layer 18 is covered under the protective layer 23.
  • Reference numeral 23 a denotes a filling portion filled between the mask pattern layers 18.
  • the optical material layer 2 is etched using the mask portion 32 in the opening 24 to form the optical element layer 25 in which the fine pattern 34 is formed.
  • the predetermined recesses 26 are regularly arranged at a constant period.
  • the non-mask portion that is not covered with the second resin layer is removed from the mask pattern layer, and then the second resin layer is removed to expose the mask portion in the transfer region. Then, the optical material layer is etched through the exposed mask portion.
  • the non-mask portion 33 not covered with the resin layer 21 is removed, so that the mask is formed on the optical element layer 2.
  • the portion 32 and the resin layer 21 covering the portion 32 are left (FIG. 6A).
  • the mask portion 32 is exposed as shown in FIG.
  • the optical material layer 2 is etched through the mask portion 32.
  • FIG. 6C the portion of the optical material layer that is not covered with the mask portion 32 is etched, and the protrusion 28 remains in the portion covered with the mask portion 32, A recess 29 is formed between them (see FIG. 6C).
  • a fine pattern 36 is formed in the transfer region B on the surface of the optical element layer 27.
  • the design pattern of the mold When the design pattern of the mold is transferred to the resin layer, it can be performed as follows. That is, when the resin layer is made of a thermoplastic resin, the resin layer can be softened by heating the resin layer to a temperature equal to or higher than the softening point of the resin, and the resin can be deformed by pressing the mold. During the subsequent cooling, the resin layer is cured.
  • the resin layer is made of a thermosetting resin
  • the mold can be pressed against the uncured resin layer to deform the resin, and then the resin layer can be heated to a temperature higher than the polymerization temperature of the resin to be cured.
  • the resin layer is formed of a photocurable resin, the mold can be pressed against the uncured resin layer to deform it, the design pattern can be transferred, and the resin layer can be irradiated with light and cured.
  • the optical material layer is preferably formed by dry etching.
  • Dry etching includes, for example, reactive etching, and examples of the gas species include fluorine and chlorine.
  • An upper clad layer can be further provided on the surface of the optical material layer.
  • the specific material of the support substrate is not particularly limited, and examples thereof include lithium niobate, lithium tantalate, AlN, SiC, ZnO, quartz glass, synthetic quartz, quartz, Si, and the like.
  • the thickness of the support substrate is preferably 250 ⁇ m or more from the viewpoint of handling, and is preferably 1 mm or less from the viewpoint of miniaturization.
  • the optical material layer is preferably formed from an optical material such as silicon oxide, zinc oxide, tantalum oxide, lithium niobate, lithium tantalate, titanium oxide, and aluminum oxide.
  • the refractive index of the optical material layer is preferably 1.7 or more, and more preferably 2.0 or more.
  • one or more metals selected from the group consisting of magnesium (Mg), zinc (Zn), scandium (Sc), and indium (In) are used to further improve the optical damage resistance of the optical waveguide. Elements may be included, in which case magnesium is particularly preferred.
  • the crystal can contain a rare earth element as a doping component. As the rare earth element, Nd, Er, Tm, Ho, Dy, and Pr are particularly preferable.
  • the thickness of the optical material layer is not particularly limited, but is preferably 0.5 to 3 ⁇ m from the viewpoint of reducing light propagation loss.
  • the lower clad layer and the upper clad layer are formed of a material having a refractive index lower than that of the optical material layer, and can be formed of, for example, silicon oxide, tantalum oxide, resin, zinc oxide, or aluminum oxide. Further, the refractive index can be adjusted by doping the lower clad layer and the upper clad layer. Examples of such dopants include P, B, Al, and Ga. Examples of the material of the mask material layer and the protective layer include Cr, Ni, Ti, Al, tungsten silicide, and the like and multilayer films thereof.
  • the optical material layer, the lower clad layer, the upper clad layer, the mask material layer, and the protective layer may each be a single layer or a multilayer film.
  • a warp correction film made of a material having the same thermal expansion coefficient as that of the clad layer and the optical material layer can be formed on the bottom surface of the support substrate.
  • the optical material layer, the clad layer, and the upper clad layer may be formed by a thin film forming method.
  • a thin film forming method examples include sputtering, vapor deposition, and CVD.
  • the optical material layer is formed directly on the support base, and an adhesive layer is not necessary.
  • the fine pattern formed on the optical material layer means a pattern having a period of 10 ⁇ m or less, and is particularly effective for a pattern having a period of 1 ⁇ m or less.
  • Examples of the fine pattern formed on the optical material layer include a sub-wavelength structure broadband wave plate, a wavelength selection element, a reflection control element, a moth-eye structure, a Bragg grating, and a ridge type optical waveguide.
  • the design pattern transfer area A includes a mask part 32 and a non-mask part 33, and the mask part 32 corresponds to the final transfer area B. Therefore, the transfer area A includes the final transfer area B of interest.
  • the width of the transfer area A / the width of the transfer area B of the design pattern is preferably 1.5 or more, and more preferably 2 or more, from the viewpoint of the effect of the present invention. If the transfer area A is too large compared to the transfer area B, the area ratio of the transfer area B becomes low. From this point of view, the width of the transfer area A of the design pattern / the width of the transfer area B is 10 The following is preferable, and 7 or less is more preferable.
  • the area of the transfer area A of the design pattern / the area of the transfer area B is preferably 2 or more, and more preferably 4 or more, from the viewpoint of the effect of the present invention. If the transfer area A is too large compared to the transfer area B, the area ratio of the transfer area B is reduced. From this point of view, the area of the transfer area A of the design pattern / the area of the transfer area B is 100 The following is preferable, and 50 or less is more preferable.
  • a mold 47 on which a Bragg grating pattern with a 200 nm pitch, a depth of 100 nm, and a duty ratio of 1: 1 was formed was produced.
  • the grating pattern is dotted with transfer regions of 200 ⁇ m in length ⁇ 200 ⁇ m in width, the ratio to the total area of the pattern formation region is 10%, and the pitch measurement result is 200 nm ⁇ 0.5 nm or less.
  • a cladding layer made of SiO 2 is formed by 1.0 ⁇ m
  • an optical material layer 2 made of Ta 2 O 5 is formed by 1.0 ⁇ m on the upper surface
  • a mask material made of Ti is further formed on the upper surface.
  • Layer 3 was deposited by 50 nm sputtering.
  • a nanoimprint resin layer 4 was applied thereon.
  • the mold 47 was pressed / ultraviolet-cured and released to form a grating mask pattern on the resin layer 5 (FIG. 1C).
  • the mask material layer 3 was etched to the surface of the optical material layer 2 by dry etching with a fluorine-based gas using the resin mask pattern 5 as a mask to remove the resin residue (FIG. 2A).
  • the optical material layer 2 is etched to a depth of 100 nm using the Ti mask pattern 8 by dry etching with a fluorine-based gas, and the remaining mask material layer is removed (FIG. 2). (B)).
  • a Bragg grating having a small pattern density and dotted with transfer regions of 200 ⁇ m in length ⁇ 200 ⁇ m in width having a pitch of 200 nm, a depth of 100 nm, and a duty ratio of 1: 1 was formed. Only this grating portion has a recess formed below with respect to the surface of the optical element layer 10.
  • pitch measurement was performed with a measuring machine using AFM and laser diffracted light capable of high precision measurement of ⁇ 0.04 nm or less.
  • the pitch was 200 ⁇ 2 nm or more over the entire surface of the ⁇ 6 inch wafer, and did not become the desired 200 ⁇ 0.5 nm or less.
  • the pitch was 200 ⁇ 5 nm or more, and the variation was large.
  • Example 1 A grating element was fabricated according to the method described with reference to FIGS.
  • a mold 7 on which a Bragg grating pattern 30 having a pitch of 200 nm, a depth of 100 nm, and a duty ratio of 1: 1 was formed was produced.
  • transfer areas A each having a length of 500 ⁇ m and a width of 500 ⁇ m are scattered, the ratio of the pattern formation area to the total area is 70%, and the pitch measurement result is 200 nm ⁇ 0.5 nm or less.
  • a cladding layer made of SiO2 is formed on a support substrate 1 made of ⁇ 6 inch Si, an optical material layer 2 made of Ta2O5 is formed on the upper surface thereof, and a mask material made of Ti is further formed on the upper surface.
  • Layer 3 was deposited by 50 nm sputtering.
  • the nanoimprint resin 4 was applied on the mask material layer 3, the mold 7 was pressed / ultraviolet-cured and released to form a resin layer 15 on which the grating mask pattern 31 was formed (FIG. 3B).
  • the mask material layer 3 made of Ti was etched to the surface of the optical material layer 2 to remove the resin residue (FIG. 3C).
  • a photoresist 20 was applied thereon (FIG. 4A), and the photoresist (resin layer) 21 was left only in the transfer region B having a length of 200 ⁇ m and a width of 200 ⁇ m using a mask aligner. This was exposed and developed, and a pattern of a desired transfer region B was scattered, and a protective layer 22 made of Ti was deposited on the upper surface by 50 nm (FIG. 4C).
  • the protective layer 22 on the photoresist is removed by a lift-off method using an organic solvent, and the mask portion 32 is used as a mask by dry etching with a fluorine-based gas in a transfer region B of 200 ⁇ m in length ⁇ 200 ⁇ m in width (FIG. 5A )),
  • the optical material layer 2 was etched to a depth of 100 nm, and the remaining Ti in the mask portion was removed (FIG. 5C).
  • a Bragg grating 34 having a small pattern density dotted with transfer regions (200 ⁇ m long ⁇ 200 nm wide) B having a pitch of 200 nm, a depth of 100 nm, and a duty ratio of 1: 1 was formed. Only this grating portion has a shape having a concave portion 26 below the surface of the optical material layer.
  • the pitch in the region of 200 ⁇ m in length ⁇ 200 ⁇ m in width with a measuring machine using diffracted light with AFM and laser capable of high accuracy measurement of ⁇ 0.04 nm or less, it is 200 ⁇ 0.2 in all ⁇ 6 inch wafer surface.
  • the desired pitch with ultra-high accuracy of nm was obtained.
  • Example 2 A grating element was fabricated according to the method described with reference to FIGS. 3, 4A, 4B, and 6.
  • a cladding layer made of SiO2 is formed by 1.0 ⁇ m
  • an optical material layer 2 made of Ta2O5 is formed by 1.0 ⁇ m on the upper surface thereof
  • a mask material made of Ti is further formed on the upper surface thereof.
  • Layer 3 was deposited by sputtering at 50 nm. The nanoimprint resin 4 was applied thereon, the mold was pressed / ultraviolet cured, and released to form the resin layer 15 on which the grating mask pattern 31 was formed.
  • the mask material layer 3 made of Ti was etched to the surface of the optical material layer 2 to remove the resin residue (FIG. 3C).
  • a photoresist 20 was applied thereon, and the photoresist was left in the transfer region B (length 200 ⁇ m ⁇ width 200 nm) with a mask aligner, and was exposed and developed.
  • the non-mask portion 33 made of Ti that is not protected by the photoresist is removed (FIG. 6A), and then the resin layer 21 is removed (FIG. 6B). .
  • the optical material layer 2 is etched to a depth of 100 nm by dry etching with a fluorine-based gas, and the remaining Ti film is removed. did.
  • a Bragg grating pattern 36 having a pitch of 200 nm, a depth of 100 nm, and a duty ratio of 1: 1 was formed on the optical element layer 27 in the transfer region B.
  • the pitch in the transfer region B (vertical 200 ⁇ m ⁇ width 200 nm) was measured by a measuring machine using AFM and laser diffracted light capable of high accuracy measurement of ⁇ 0.04 nm or less. As a result, a desired pitch with an ultra-high accuracy of 200 ⁇ 0.2 nm was obtained in the entire ⁇ 6 inch wafer surface.
  • the pitches of the gratings formed in Examples 1 and 2 of the present invention were both 200 ⁇ 0.2 nm and the desired 200 ⁇ 0.5 nm or less. In the comparative example, such a fine pattern having a small dimension could not be formed with high transfer accuracy.

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Abstract

With respect to an assembly which is provided with a supporting substrate (1), an optical material layer (2), a mask material layer and a first resin layer, a design pattern is transferred to the first resin layer by an imprint method using a mold that is provided with the design pattern that corresponds to a fine pattern. A mask pattern layer (18) is formed by patterning the mask material layer. Subsequently, a second resin layer (21), which covers a mask part (32) of the mask pattern layer (18), said mask part (32) corresponding to a transfer region B, and does not cover a non-mask part (33) other than the mask part, is formed. After that, a protective layer (22) that covers the mask part (32) is provided and the mask part (32) is exposed by removing the second resin layer (21) by a lift-off method, and an optical element layer having the fine pattern is formed by etching the optical material layer (2) with use of the mask part (32).

Description

光学デバイスの製造方法Optical device manufacturing method
　本発明は、グレーティング素子などの光学デバイスの製造方法に関するものである。 The present invention relates to a method for manufacturing an optical device such as a grating element.
　半導体レーザ素子が有する回折格子を形成する方法として、ナノインプリント(nanoimprinting)法を採用することが検討されている。回折格子の形成にナノインプリント法を採用することで、半導体レーザ等のデバイスの製造コストを低減させることができる等の利点がある。 The adoption of a nanoimprinting method as a method for forming a diffraction grating of a semiconductor laser element has been studied. Adopting the nanoimprint method for forming the diffraction grating has an advantage that the manufacturing cost of a device such as a semiconductor laser can be reduced.
　ナノインプリント法によって回折格子を形成する際には、まず、回折格子を形成すべき半導体層上に樹脂層を形成する。そして、この回折格子の形状に対応した凹凸パターンを有するモールド(mold)をこの樹脂層に押し付け、その状態で樹脂層を硬化させる。これにより、モールドの凹凸パターンを樹脂層に転写する。その後、この樹脂層の形状を半導体層に転写することにより、半導体層に微細構造を形成する。 When forming a diffraction grating by the nanoimprint method, first, a resin layer is formed on a semiconductor layer on which the diffraction grating is to be formed. Then, a mold having a concavo-convex pattern corresponding to the shape of the diffraction grating is pressed against the resin layer, and the resin layer is cured in this state. Thereby, the uneven | corrugated pattern of a mold is transcribe | transferred to a resin layer. Thereafter, the shape of the resin layer is transferred to the semiconductor layer, thereby forming a fine structure in the semiconductor layer.
　特許文献１には、ナノインプリント法を用いた分布帰還型半導体レーザの製造方法が記載されている。この方法では、分布帰還型半導体レーザの回折格子のための半導体層のパターニングを、ナノインプリント法で行っている。 Patent Document 1 describes a method of manufacturing a distributed feedback semiconductor laser using a nanoimprint method. In this method, patterning of a semiconductor layer for a diffraction grating of a distributed feedback semiconductor laser is performed by a nanoimprint method.
　また、非特許文献１、２には、ナノインプリント技術を利用したサブ波長構造広帯域波長板の製作が記載されている。 Also, Non-Patent Documents 1 and 2 describe the production of a subwavelength structured broadband wave plate using nanoimprint technology.
　更に、非特許文献３には、光学デバイスを作製するためにナノインプリント技術を応用することが記載されている。こうした光学デバイスとしては、波長選択素子、反射制御素子、モス・アイ(Moth-Eye)構造などが例示されている。 Furthermore, Non-Patent Document 3 describes that nanoimprint technology is applied to produce an optical device. Examples of such optical devices include a wavelength selection element, a reflection control element, and a moth-eye structure.
特開２０１３－０１６６５０JP2013-016650A 特開２００９－１１１４２３JP 2009-111423
　ナノインプリント法にて微細構造を樹脂層に転写する場合、転写領域が大きい場合には問題が発生し難い。しかし、光学材料層の一部にしか微細パターンを転写しない場合、すなわち微細パターンの幅が狭い場合には、微細パターンの転写精度が低下するという問題があることがわかった。例えばブラッググレーティングを転写した場合、グレーティングピッチの精度が低下するという問題が生ずる。 When transferring the fine structure to the resin layer by the nanoimprint method, the problem hardly occurs when the transfer area is large. However, it has been found that when the fine pattern is transferred only to a part of the optical material layer, that is, when the width of the fine pattern is narrow, the transfer accuracy of the fine pattern is lowered. For example, when a Bragg grating is transferred, there arises a problem that the accuracy of the grating pitch is lowered.
　本発明の課題は、インプリント法によって光学材料層に微細構造を形成するのに際して、転写領域が小さい場合にも微細パターンの転写精度を向上させる方法を提供することである。 An object of the present invention is to provide a method for improving the transfer accuracy of a fine pattern even when a transfer region is small when forming a fine structure in an optical material layer by an imprint method.
　本発明は、支持基板、
　支持基板上に設けられた光学素子層、および
　転写領域において光学素子層に形成された微細パターンを有する光学デバイスを製造する方法であって、
　支持基板、光学材料層、マスク材料層および第一の樹脂層を備えるアセンブリに対して、微細パターンに対応する設計パターンの形成されたモールドを用いてインプリント法によって第一の樹脂層に設計パターンを転写し、マスク材料層をパターニングしてマスクパターン(mask pattern)層を形成し、次いでマスクパターン層のうち転写領域に対応するマスク部を被覆し、かつマスク部以外の非マスク部を被覆しない第二の樹脂層を形成し、次いでこのマスク部を介して光学材料層をエッチングすることによって、前記微細パターンを有する前記光学素子層を形成することを特徴とする。 The present invention provides a support substrate,
An optical element layer provided on a support substrate, and a method of manufacturing an optical device having a fine pattern formed on the optical element layer in a transfer region,
For an assembly including a support substrate, an optical material layer, a mask material layer, and a first resin layer, a design pattern is formed on the first resin layer by an imprint method using a mold having a design pattern corresponding to a fine pattern. And patterning the mask material layer to form a mask pattern layer, and then covering the mask pattern layer corresponding to the transfer region and not covering the non-mask portion other than the mask portion. The optical element layer having the fine pattern is formed by forming a second resin layer and then etching the optical material layer through the mask portion.
　インプリント法によって微細パターンを光学材料層に転写する場合、転写領域が小さくなると転写精度が低下し易い理由について検討し、以下の知見を得た。以下、適宜図面を参照しつつ説明する。 When transferring the fine pattern to the optical material layer by the imprint method, the reason why the transfer accuracy is likely to be lowered when the transfer area is small was examined, and the following knowledge was obtained. Hereinafter, description will be given with reference to the drawings as appropriate.
　図１（ａ）に示すように、支持基板１上に光学材料層２、マスク材料層３、第一の樹脂層４を形成し、加工用のアセンブリ４０を得る。次いで、図１（ｂ）に示すように、所定の微細パターンが形成されたモールド４７を第一の樹脂層に接触させ、微細パターンを転写する。４７ａはモールド４７の突起であり、６はモールド４７の凹部内に充填された樹脂である。５は圧縮された樹脂層である。 As shown in FIG. 1A, an optical material layer 2, a mask material layer 3, and a first resin layer 4 are formed on a support substrate 1, and a processing assembly 40 is obtained. Next, as shown in FIG. 1B, a mold 47 on which a predetermined fine pattern is formed is brought into contact with the first resin layer to transfer the fine pattern. 47 a is a protrusion of the mold 47, and 6 is a resin filled in the recess of the mold 47. Reference numeral 5 denotes a compressed resin layer.
　このとき、微細パターンの転写領域が大きい場合には転写を精度よく行い易い。これは、微細パターンの各部分に均等に圧力が加わりやすいためと考えられる。ところが、微細パターンの転写領域が小さい場合には、突起４７ａ間の凹部中に充填される樹脂６の量が少なくなる。このため転写時に矢印Ａで示すように圧力が加わって突起４７ａが変形し易くなる。この結果、モールド４７を除去した後では、樹脂層５の表面に残留する突起６の形状が変形し、形状精度が低下する(図1(ｃ)参照)。 At this time, when the transfer area of the fine pattern is large, it is easy to perform the transfer with high accuracy. This is considered to be because pressure is easily applied evenly to each portion of the fine pattern. However, when the transfer area of the fine pattern is small, the amount of the resin 6 filled in the recesses between the protrusions 47a is reduced. For this reason, a pressure is applied as shown by an arrow A during transfer, and the protrusion 47a is easily deformed. As a result, after the mold 47 is removed, the shape of the protrusion 6 remaining on the surface of the resin layer 5 is deformed, and the shape accuracy is lowered (see FIG. 1C).
　この状態でマスク材料層３をエッチングし、図２（ａ）に示すようにマスク層８を形成すると、マスク層８には所望の微細パターンに対応する凸部９が形成される。しかし、この凸部９も所望形状から見て変形している。この状態でマスク層８を介して光学材料層２をエッチングすると、図２（ｂ）に示すように、凸部１１からなる微細構造を有する光学素子層１０が形成される。しかし、各凸部１１の形状やピッチは、所望形状や所望ピッチからは外れてくる。 In this state, when the mask material layer 3 is etched to form the mask layer 8 as shown in FIG. 2 (a), the mask layer 8 is provided with a convex portion 9 corresponding to a desired fine pattern. However, this convex portion 9 is also deformed as viewed from the desired shape. When the optical material layer 2 is etched through the mask layer 8 in this state, as shown in FIG. 2B, an optical element layer 10 having a fine structure composed of convex portions 11 is formed. However, the shape and pitch of each convex part 11 deviate from the desired shape and desired pitch.
　以上の知見から考えると、微細パターンの転写領域が小さい場合には、モールドから樹脂層への微細パターンの転写時に、モールドの凹部に充填された樹脂の量が少なく、このためにパターンの変形が起きやすいことがわかった。 Considering the above knowledge, when the transfer area of the fine pattern is small, the amount of the resin filled in the concave portion of the mold is small at the time of transferring the fine pattern from the mold to the resin layer. I found it easy to get up.
　このため、本発明者は、例えば図３（ａ）に示すように、まず所望の転写領域よりも寸法の大きい領域Ａにわたってモールド７の微細パターン３０を樹脂層１５に転写してみた。この場合には前述のような樹脂充填量の少なさによる微細パターンの変形は生じにくい。そして、図３（ｃ）に示すように領域Ａの全体にわたってマスクパターン層１８を形成した後、図４（ｂ）に示すように、領域Ａに含まれる一部領域Ｂのみにおいてマスクパターン層１８を第二の樹脂層２１によって被覆することを想到した。この段階で、マスクパターン層１８は、第二の樹脂層２１によって被覆されたマスク部３２と、被覆されない非マスク部３３とに分ける。 For this reason, for example, as shown in FIG. 3A, the present inventor first tried to transfer the fine pattern 30 of the mold 7 to the resin layer 15 over the region A having a dimension larger than the desired transfer region. In this case, the fine pattern is hardly deformed due to the small amount of the resin filling as described above. Then, after forming the mask pattern layer 18 over the entire area A as shown in FIG. 3C, the mask pattern layer 18 is formed only in the partial area B included in the area A as shown in FIG. It was conceived that the second resin layer 21 was covered. At this stage, the mask pattern layer 18 is divided into a mask portion 32 covered with the second resin layer 21 and a non-mask portion 33 that is not covered.
　この状態で、図５（ａ）や図６（ｂ）に示すように、第二の樹脂層２１を除去してマスク部３２を露出させ、エッチングを行うことで、所望の転写領域Ｂにおいて微細構造３４を光学材料層に形成することができる。上記方法を用いる事で、従来の一括転写式ナノインプリントでは困難であった小さいものでも、高精度での微細パターン形成が可能である事が、パターンの寸法測定から明らかになった。 In this state, as shown in FIG. 5A and FIG. 6B, the second resin layer 21 is removed to expose the mask portion 32, and etching is performed. Structure 34 may be formed in the optical material layer. By using the above method, it was revealed from pattern dimension measurement that a fine pattern can be formed with high accuracy even with a small one that was difficult with the conventional batch transfer nanoimprint.
図１、図２は参考形態を示すものである。（ａ）は、加工すべきアセンブリを示す模式図であり、（ｂ）は、モールド４７の微細パターンを樹脂層に転写している状態を示し、（ｃ）は、樹脂層５に微細パターンを転写した状態を示す。1 and 2 show a reference form. (A) is a schematic diagram which shows the assembly which should be processed, (b) shows the state which has transferred the fine pattern of the mold 47 to the resin layer, (c) shows the fine pattern on the resin layer 5 The transferred state is shown. （ａ）は、マスク層８を形成した状態を示し、（ｂ）は、微細パターンが転写された光学素子層１０を示す。(A) shows the state in which the mask layer 8 is formed, and (b) shows the optical element layer 10 to which the fine pattern has been transferred. （ａ）は、樹脂層１５にモールド７の微細パターンを転写した状態を示し、（ｂ）は、微細パターンが転写された樹脂層を示し、（ｃ）は、マスクパターン層１８を示す。(A) shows the state where the fine pattern of the mold 7 has been transferred to the resin layer 15, (b) shows the resin layer to which the fine pattern has been transferred, and (c) shows the mask pattern layer 18. （ａ）は、マスクパターン層１８上に樹脂層２０を形成した状態を示し、（ｂ）は、転写領域Ｂにおいてマスクパターン層１８上に第二の樹脂層２１を形成した状態を示し、（ｃ）は、マスクパターン層および樹脂層を保護層２２によって被覆した状態を示す。(A) shows the state in which the resin layer 20 is formed on the mask pattern layer 18, (b) shows the state in which the second resin layer 21 is formed on the mask pattern layer 18 in the transfer region B, ( c) shows a state in which the mask pattern layer and the resin layer are covered with the protective layer 22. （ａ）は、リフトオフ法によってマスク部３２を露出させた状態を示し、（ｂ）は、光学素子層２５に微細パターン３４を形成した状態を示し、（ｃ）は、光学デバイスを示す。(A) shows a state in which the mask portion 32 is exposed by the lift-off method, (b) shows a state in which the fine pattern 34 is formed on the optical element layer 25, and (c) shows an optical device. 図６は他の実施形態に係るものである。（ａ）は、光学材料層２上にマスク部１８および第二の樹脂層２１を残留させた状態を示し、（ｂ）は、樹脂層２１を除去してマスク部１８を露出させた状態を示し、（ｃ）は、光学材料層をエッチングして微細パターン３６を形成した状態を示す。FIG. 6 relates to another embodiment. (A) shows a state in which the mask portion 18 and the second resin layer 21 are left on the optical material layer 2, and (b) shows a state in which the mask portion 18 is exposed by removing the resin layer 21. (C) shows a state in which the fine pattern 36 is formed by etching the optical material layer.
　図３～図５は第一の実施形態に係るものである。
　まず、図１（ａ）に示すように、支持基板１、光学材料層２、マスク材料層３および樹脂層４を含むアセンブリ４０を準備する。次いで、図３（ａ）に示すように、所定領域Ａにわたって微細パターン３０が形成されたモールド７を樹脂層４に対して接触させ、微細パターンが転写された樹脂層１５を形成する。７ａは突起である。次いでモールド７を除去することで、図３（ｂ）に示すように、樹脂層１５の微細パターン３１が露出する。この微細パターン３１は、一定周期で形成された多数の突起１５ａからなり、隣接する突起間に凹部１６が形成されている。 3 to 5 relate to the first embodiment.
First, as shown in FIG. 1A, an assembly 40 including a support substrate 1, an optical material layer 2, a mask material layer 3, and a resin layer 4 is prepared. Next, as shown in FIG. 3A, the mold 7 on which the fine pattern 30 is formed over the predetermined area A is brought into contact with the resin layer 4 to form the resin layer 15 to which the fine pattern is transferred. 7a is a protrusion. Next, by removing the mold 7, the fine pattern 31 of the resin layer 15 is exposed as shown in FIG. The fine pattern 31 is composed of a large number of protrusions 15a formed at a constant period, and a recess 16 is formed between adjacent protrusions.
　この段階では、最終的に目的とする転写領域Ｂを含み、転写領域Ｂよりも寸法の大きい所定領域Ａにわたって微細パターン３０を転写している。従って、所定領域Ａの寸法は相対的に大きいので、微細パターンの転写精度を高く保持できる。 At this stage, the fine pattern 30 is transferred over the predetermined area A that includes the final transfer area B and has a dimension larger than that of the transfer area B. Accordingly, since the size of the predetermined area A is relatively large, it is possible to maintain high transfer accuracy of the fine pattern.
　次いで、樹脂層１５およびその下にあるマスク材料層３をエッチングすることで、マスクパターン層１８を形成する（図３（ｃ））。マスクパターン層１８には一定周期で凹部１９が形成されている。必要に応じて、残留した樹脂層１５を除去する（アッシング）。 Then, the mask pattern layer 18 is formed by etching the resin layer 15 and the underlying mask material layer 3 (FIG. 3C). Concave portions 19 are formed in the mask pattern layer 18 at regular intervals. If necessary, the remaining resin layer 15 is removed (ashing).
　次いで、図４（ａ）に示すように、マスクパターン層１８の全体にわたって樹脂層２０によって被覆する。２０ａは平坦部分であり、２０ｂは、マスクパターン層１８の凹部に充填された樹脂である。 Next, as shown in FIG. 4A, the entire mask pattern layer 18 is covered with a resin layer 20. Reference numeral 20a denotes a flat portion, and reference numeral 20b denotes a resin filled in the recesses of the mask pattern layer 18.
　次いで、樹脂層２０をフォトリソグラフィーによって露光することで、図４（ｂ）に示すように第二の樹脂層２１を残留させる。２１ａは平坦部分、２１ｂは凹部への充填部分である。ここで、樹脂層２１は、最終的な転写領域Ｂにおいてマスクパターン層１８を被覆するが、マスクパターン層１８の残りは樹脂層２１によって被覆されない。この結果、マスクパターン層１８は、樹脂層２１によって被覆されたマスク部３２と、樹脂層２１によって被覆されない非マスク部３３とに分割される。 Next, the resin layer 20 is exposed by photolithography to leave the second resin layer 21 as shown in FIG. 21a is a flat part, 21b is a filling part to a recessed part. Here, the resin layer 21 covers the mask pattern layer 18 in the final transfer region B, but the rest of the mask pattern layer 18 is not covered by the resin layer 21. As a result, the mask pattern layer 18 is divided into a mask portion 32 covered with the resin layer 21 and a non-mask portion 33 not covered with the resin layer 21.
　次いで図４（ｃ）に示すように、マスクパターン層１８および樹脂層２１を被覆する保護層２２を形成する。 Next, as shown in FIG. 4C, a protective layer 22 covering the mask pattern layer 18 and the resin layer 21 is formed.
　次いで、リフトオフ法によって樹脂層２１を除去し、図５（ａ）に示すように保護層２３を形成する。この際、最終的な転写領域Ｂに合わせて開口２４を形成するようにする。この状態で、開口２４には、マスクパターン層１８のマスク部３２が露出している。一方、マスクパターン層１８の非マスク部３３は保護層２３下に被覆されている。なお、２３ａは、マスクパターン層１８間に充填された充填部分である。 Next, the resin layer 21 is removed by a lift-off method, and a protective layer 23 is formed as shown in FIG. At this time, the opening 24 is formed in accordance with the final transfer region B. In this state, the mask portion 32 of the mask pattern layer 18 is exposed in the opening 24. On the other hand, the non-mask portion 33 of the mask pattern layer 18 is covered under the protective layer 23. Reference numeral 23 a denotes a filling portion filled between the mask pattern layers 18.
　次いで、図５（ｂ）に示すように、開口２４内において、マスク部３２を用いて光学材料層２をエッチングし、微細パターン３４が形成された光学素子層２５を形成する。微細パターン３４においては、所定の凹部２６が一定周期で規則的に配列されている。 Next, as shown in FIG. 5B, the optical material layer 2 is etched using the mask portion 32 in the opening 24 to form the optical element layer 25 in which the fine pattern 34 is formed. In the fine pattern 34, the predetermined recesses 26 are regularly arranged at a constant period.
　次いで、保護層２３および非マスク部３３を除去し、図５（ｃ）に示すような光学素子層２５を得る。 Next, the protective layer 23 and the non-mask portion 33 are removed to obtain an optical element layer 25 as shown in FIG.
　また、好適な実施形態においては、マスクパターン層のうち第二の樹脂層によって被覆されていない非マスク部を除去し、次いで第二の樹脂層を除去することで転写領域においてマスク部を露出させ、この露出したマスク部を介して光学材料層をエッチングする。 In a preferred embodiment, the non-mask portion that is not covered with the second resin layer is removed from the mask pattern layer, and then the second resin layer is removed to expose the mask portion in the transfer region. Then, the optical material layer is etched through the exposed mask portion.
 すなわち、図4(ｂ)のように転写領域Ｂに第二の樹脂層２１を形成した後、樹脂層２１によって被覆されていない非マスク部３３を除去することで、光学素子層２上にマスク部３２およびそれを被覆する樹脂層２１を残留させる（図６（ａ））。次いで、樹脂層２１を除去することで、図６（ｂ）に示すようにマスク部３２を露出させる。次いで、マスク部３２を介して光学材料層２をエッチングする。この結果、図６（ｃ）に示すように、光学材料層のうちマスク部３２によって被覆されていない部分はエッチングされ、マスク部３２によって被覆された部分には突起２８が残留し、突起２８の間に凹部２９が形成される（図６（ｃ）参照）。この結果、光学素子層２７の表面に微細パターン３６が転写領域Ｂにおいて形成される。 That is, after forming the second resin layer 21 in the transfer region B as shown in FIG. 4B, the non-mask portion 33 not covered with the resin layer 21 is removed, so that the mask is formed on the optical element layer 2. The portion 32 and the resin layer 21 covering the portion 32 are left (FIG. 6A). Next, by removing the resin layer 21, the mask portion 32 is exposed as shown in FIG. Next, the optical material layer 2 is etched through the mask portion 32. As a result, as shown in FIG. 6C, the portion of the optical material layer that is not covered with the mask portion 32 is etched, and the protrusion 28 remains in the portion covered with the mask portion 32, A recess 29 is formed between them (see FIG. 6C). As a result, a fine pattern 36 is formed in the transfer region B on the surface of the optical element layer 27.
　モールドの設計パターンを樹脂層に転写する場合には、以下のように行うことができる。
　すなわち、樹脂層が熱可塑性樹脂からなる場合には、樹脂層を樹脂の軟化点以上に加熱することによって樹脂層を軟化させ、モールドを押しつけて樹脂を変形させることができる。この後の冷却時に樹脂層が硬化する。樹脂層が熱硬化性樹脂からなる場合には、未硬化の樹脂層に対してモールドを押しつけて樹脂を変形させ，次いで樹脂層を樹脂の重合温度以上に加熱して硬化させることができる。樹脂層を光硬化性樹脂によって形成した場合には、未硬化の樹脂層にモールドを押しつけて変形させ、設計パターンを転写し、樹脂層に光を照射して硬化させることができる。 When the design pattern of the mold is transferred to the resin layer, it can be performed as follows.
That is, when the resin layer is made of a thermoplastic resin, the resin layer can be softened by heating the resin layer to a temperature equal to or higher than the softening point of the resin, and the resin can be deformed by pressing the mold. During the subsequent cooling, the resin layer is cured. When the resin layer is made of a thermosetting resin, the mold can be pressed against the uncured resin layer to deform the resin, and then the resin layer can be heated to a temperature higher than the polymerization temperature of the resin to be cured. When the resin layer is formed of a photocurable resin, the mold can be pressed against the uncured resin layer to deform it, the design pattern can be transferred, and the resin layer can be irradiated with light and cured.
　光学材料層はドライエッチングによって成形することが好ましい。
　ドライエッチングは例えば、反応性エッチング等が有り、ガス種としてフッ素系・塩素系が例示できる。 The optical material layer is preferably formed by dry etching.
Dry etching includes, for example, reactive etching, and examples of the gas species include fluorine and chlorine.
　なお、光学材料層の表面に上側クラッド層をさらに設けることもできる。 An upper clad layer can be further provided on the surface of the optical material layer.
　支持基板の具体的材質は特に限定されず，ニオブ酸リチウム、タンタル酸リチウム、ＡｌＮ、ＳｉＣ、ＺｎＯ、石英ガラスなどのガラス、合成石英、水晶、Ｓｉなどを例示することができる。 The specific material of the support substrate is not particularly limited, and examples thereof include lithium niobate, lithium tantalate, AlN, SiC, ZnO, quartz glass, synthetic quartz, quartz, Si, and the like.
　支持基板の厚さは、ハンドリングの観点からは、２５０μｍ以上が好ましく、また小型化という観点からは、１ｍｍ以下が好ましい。 The thickness of the support substrate is preferably 250 μm or more from the viewpoint of handling, and is preferably 1 mm or less from the viewpoint of miniaturization.
　光学材料層は、酸化珪素、酸化亜鉛、酸化タンタル、ニオブ酸リチウム、タンタル酸リチウム、酸化チタン、酸化アルミニウム等の光学材料から形成することが好ましい。また、光学材料層の屈折率は、１．７以上が好ましく、２．０以上がさらに好ましい。 The optical material layer is preferably formed from an optical material such as silicon oxide, zinc oxide, tantalum oxide, lithium niobate, lithium tantalate, titanium oxide, and aluminum oxide. The refractive index of the optical material layer is preferably 1.7 or more, and more preferably 2.0 or more.
　光学材料層中には、光導波路の耐光損傷性を更に向上させるために、マグネシウム（Ｍｇ）、亜鉛（Ｚｎ）、スカンジウム（Ｓｃ）及びインジウム（Ｉｎ）からなる群より選ばれる１種以上の金属元素を含有させてもよく、この場合、マグネシウムが特に好ましい。また結晶中には、ドープ成分として、希土類元素を含有させることができる。希土類元素としては、特にＮｄ、Ｅｒ、Ｔｍ、Ｈｏ、Ｄｙ、Ｐｒが好ましい。 In the optical material layer, one or more metals selected from the group consisting of magnesium (Mg), zinc (Zn), scandium (Sc), and indium (In) are used to further improve the optical damage resistance of the optical waveguide. Elements may be included, in which case magnesium is particularly preferred. The crystal can contain a rare earth element as a doping component. As the rare earth element, Nd, Er, Tm, Ho, Dy, and Pr are particularly preferable.
　光学材料層の厚さは、特に限定されないが、光の伝搬損失を低減するという観点からは、０．５～３μｍが好ましい。 The thickness of the optical material layer is not particularly limited, but is preferably 0.5 to 3 μm from the viewpoint of reducing light propagation loss.
　下側クラッド層および上側クラッド層は、光学材料層の材質よりも低い屈折率を有する材質から形成するが、たとえば酸化珪素、酸化タンタル、樹脂、酸化亜鉛、酸化アルミニウムによって形成することができる。また、下側クラッド層や上側クラッド層にドーピングすることによって、その屈折率を調整することができる。こうしたドーパントとしては、P、B、Al、Gaを例示できる。
　マスク材料層、保護層の材質としては、Cr、Ni、Ti、Al、タングステンシリサイド等及びその多層膜が例示できる。 The lower clad layer and the upper clad layer are formed of a material having a refractive index lower than that of the optical material layer, and can be formed of, for example, silicon oxide, tantalum oxide, resin, zinc oxide, or aluminum oxide. Further, the refractive index can be adjusted by doping the lower clad layer and the upper clad layer. Examples of such dopants include P, B, Al, and Ga.
Examples of the material of the mask material layer and the protective layer include Cr, Ni, Ti, Al, tungsten silicide, and the like and multilayer films thereof.
　グレーティング層とマスク材料層との間に他の層を入れても構わない Other layers may be inserted between the grating layer and the mask material layer
　光学材料層、下側クラッド層、上側クラッド層、マスク材料層、保護層は、それぞれ、単層からなっていてよく、あるいは多層膜であっても良い。 The optical material layer, the lower clad layer, the upper clad layer, the mask material layer, and the protective layer may each be a single layer or a multilayer film.
　なお、支持基板の底面に、クラッド層や光学材料層と同じ熱膨張係数を有する材質からなる反り補正の膜を形成することもできる。 Note that a warp correction film made of a material having the same thermal expansion coefficient as that of the clad layer and the optical material layer can be formed on the bottom surface of the support substrate.
　また、光学材料層、クラッド層、上側クラッド層は、薄膜形成法によって成膜して形成してもよい。こうした薄膜形成法としては、スパッタ、蒸着、ＣＶＤを例示できる。この場合には、光学材料層は支持基体に直接形成されており、接着層は不要になる。 Further, the optical material layer, the clad layer, and the upper clad layer may be formed by a thin film forming method. Examples of such a thin film forming method include sputtering, vapor deposition, and CVD. In this case, the optical material layer is formed directly on the support base, and an adhesive layer is not necessary.
　光学材料層に形成する微細パターンとは、一周期が１０μｍ以下のパターンを意味しており、一周期が１μｍ以下のパターンに対して特に効果的である。光学材料層に形成する微細パターンとしては、サブ波長構造広帯域波長板、波長選択素子、反射制御素子、モス・アイ構造、ブラッググレーティング、リッジ型光導波路などを例示できる。 The fine pattern formed on the optical material layer means a pattern having a period of 10 μm or less, and is particularly effective for a pattern having a period of 1 μm or less. Examples of the fine pattern formed on the optical material layer include a sub-wavelength structure broadband wave plate, a wavelength selection element, a reflection control element, a moth-eye structure, a Bragg grating, and a ridge type optical waveguide.
　設計パターンの転写領域Ａは、マスク部３２と非マスク部３３とを含んでおり、マスク部３２が最終的な転写領域Ｂに対応する。従って、転写領域Ａは、目的とする最終的な転写領域Ｂを含む。 The design pattern transfer area A includes a mask part 32 and a non-mask part 33, and the mask part 32 corresponds to the final transfer area B. Therefore, the transfer area A includes the final transfer area B of interest.
　ここで、設計パターンの転写領域Ａの幅／転写領域Ｂの幅は、本発明の効果という観点からは、1.5以上が好ましく、2以上が更に好ましい。また、転写領域Ａが転写領域Ｂに比べて大きくなりすぎると、転写領域Ｂの面積比率が低くなるので、この観点からは、設計パターンの転写領域Ａの幅／転写領域Ｂの幅は、10以下が好ましく、7以下が更に好ましい。 Here, the width of the transfer area A / the width of the transfer area B of the design pattern is preferably 1.5 or more, and more preferably 2 or more, from the viewpoint of the effect of the present invention. If the transfer area A is too large compared to the transfer area B, the area ratio of the transfer area B becomes low. From this point of view, the width of the transfer area A of the design pattern / the width of the transfer area B is 10 The following is preferable, and 7 or less is more preferable.
　また、同様の理由から、設計パターンの転写領域Ａの面積／転写領域Ｂの面積は、本発明の効果という観点からは、2以上が好ましく、4以上が更に好ましい。また、転写領域Ａが転写領域Ｂに比べて大きくなりすぎると、転写領域Ｂの面積比率が低くなるので、この観点からは、設計パターンの転写領域Ａの面積／転写領域Ｂの面積は、100以下が好ましく、50以下が更に好ましい。 For the same reason, the area of the transfer area A of the design pattern / the area of the transfer area B is preferably 2 or more, and more preferably 4 or more, from the viewpoint of the effect of the present invention. If the transfer area A is too large compared to the transfer area B, the area ratio of the transfer area B is reduced. From this point of view, the area of the transfer area A of the design pattern / the area of the transfer area B is 100 The following is preferable, and 50 or less is more preferable.
（比較例）
　図１、図２を参照しつつ説明した方法にしたがって、グレーティング素子を作製した。 (Comparative example)
A grating element was fabricated according to the method described with reference to FIGS.
　ArF液浸ステッパ露光を使用して、200nmピッチ・深さ100nm・デューティ比1:1のブラッググレーティングパターンが形成されたモールド４７を作製した。この際、グレーティングパターンは、縦200μm×横200μｍの転写領域が点在しており、パターン形成領域の全面積に対する比率が１０％であり、ピッチ測定結果は200nm±0.5nm以下となっている。 Using ArF immersion stepper exposure, a mold 47 on which a Bragg grating pattern with a 200 nm pitch, a depth of 100 nm, and a duty ratio of 1: 1 was formed was produced. At this time, the grating pattern is dotted with transfer regions of 200 μm in length × 200 μm in width, the ratio to the total area of the pattern formation region is 10%, and the pitch measurement result is 200 nm ± 0.5 nm or less.
  Φ6インチのシリコンからなる支持基板１上に、SiO2からなるクラッド層を1.0μm成膜し、その上面にTa2O5からなる光学材料層２を1.0μm成膜し、更にその上面にＴｉからなるマスク材料層３を50nmスパッタにて成膜した。この上にナノインプリント樹脂層４を塗布した。 On the support substrate 1 made of Φ6 inch silicon, a cladding layer made of SiO 2 is formed by 1.0 μm, an optical material layer 2 made of Ta 2 O 5 is formed by 1.0 μm on the upper surface, and a mask material made of Ti is further formed on the upper surface. Layer 3 was deposited by 50 nm sputtering. A nanoimprint resin layer 4 was applied thereon.
  次いで、モールド４７をプレス・紫外線硬化させ、離型させて、樹脂層５にグレーティングマスクパターンを形成した（図１（ｃ））。次いで、フッ素系ガスによるドライエッチングにて樹脂マスクパターン５をマスクとし、マスク材料層３を光学材料層２の表面までエッチングし、樹脂残りを除去した（図２（ａ））。次いで、縦200μm×横200μmの転写領域において、フッ素系ガスによるドライエッチングにてTiマスクパターン８を用いて、光学材料層２を100nmの深さまでエッチングし、マスク材料層残りを除去した（図２（ｂ））。 Next, the mold 47 was pressed / ultraviolet-cured and released to form a grating mask pattern on the resin layer 5 (FIG. 1C). Next, the mask material layer 3 was etched to the surface of the optical material layer 2 by dry etching with a fluorine-based gas using the resin mask pattern 5 as a mask to remove the resin residue (FIG. 2A). Next, in the transfer region of 200 μm in length × 200 μm in width, the optical material layer 2 is etched to a depth of 100 nm using the Ti mask pattern 8 by dry etching with a fluorine-based gas, and the remaining mask material layer is removed (FIG. 2). (B)).
　以上により、200nmピッチ・深さ100nm・デューティ比1:1の縦200μm×横200μmの転写領域が点在した、パターン密度が小さいブラッググレーティングが形成された。このグレーティング部のみ、光学素子層１０の表面を基準として下方に凹部が形成されている。 As described above, a Bragg grating having a small pattern density and dotted with transfer regions of 200 μm in length × 200 μm in width having a pitch of 200 nm, a depth of 100 nm, and a duty ratio of 1: 1 was formed. Only this grating portion has a recess formed below with respect to the surface of the optical element layer 10.
　縦200μm×横200μmの転写領域において、ピッチ測定を、±0.04nm以下の高精度測定が可能なAFM及びレーザーによる回折光を用いた測定機により実施した。この結果、φ6インチウェハ面内全てにおいて、ピッチは200±2nm以上となり、所望の200±0.5nm以下にならなかった。特にグレーティングパターン端部では、ピッチが200±5nm以上となり、バラツキが大きくなっていた。 In the transfer region of 200 μm in length and 200 μm in width, pitch measurement was performed with a measuring machine using AFM and laser diffracted light capable of high precision measurement of ± 0.04 nm or less. As a result, the pitch was 200 ± 2 nm or more over the entire surface of the φ6 inch wafer, and did not become the desired 200 ± 0.5 nm or less. In particular, at the edge of the grating pattern, the pitch was 200 ± 5 nm or more, and the variation was large.
　この理由として、モールド４７を樹脂層４にプレスする際、転写領域が小さいと、モールド凹部への樹脂充填量が少なくなり、その樹脂の逃げ先が無くなり、グレーティング部が倒れてしまうことが原因と考えられる。 The reason for this is that when the mold 47 is pressed onto the resin layer 4, if the transfer area is small, the resin filling amount in the mold concave portion is reduced, the resin escape destination is lost, and the grating portion falls down. Conceivable.
（実施例１）
　図３～図５を参照しつつ説明した方法にしたがって、グレーティング素子を作製した。 (Example 1)
A grating element was fabricated according to the method described with reference to FIGS.
　ArF液浸ステッパ露光を使用して、200nmピッチ・深さ100nm・デューティ比1:1のブラッググレーティングパターン３０が形成されたモールド７を作製した。この際、縦５００μm×横５００μｍの転写領域Ａが点在しており、パターン形成領域の全面積に対する比率が７０％であり、ピッチ測定結果は200nm±0.5nm以下となっている。 Using ArF immersion stepper exposure, a mold 7 on which a Bragg grating pattern 30 having a pitch of 200 nm, a depth of 100 nm, and a duty ratio of 1: 1 was formed was produced. At this time, transfer areas A each having a length of 500 μm and a width of 500 μm are scattered, the ratio of the pattern formation area to the total area is 70%, and the pitch measurement result is 200 nm ± 0.5 nm or less.
　Φ6インチの Siからなる支持基板１上に、SiO2からなるクラッド層を1.0μm成膜し、その上面にTa2O5からなる光学材料層２を1.0μm成膜し、更にその上面にＴｉからなるマスク材料層３を50nmスパッタにて成膜した。マスク材料層３上にナノインプリント樹脂４を塗布し，モールド７をプレス・紫外線硬化させ、離型させ、グレーティングマスクパターン３１が形成された樹脂層１５を形成した（図３（ｂ））。 A cladding layer made of SiO2 is formed on a support substrate 1 made of Φ6 inch Si, an optical material layer 2 made of Ta2O5 is formed on the upper surface thereof, and a mask material made of Ti is further formed on the upper surface. Layer 3 was deposited by 50 nm sputtering. The nanoimprint resin 4 was applied on the mask material layer 3, the mold 7 was pressed / ultraviolet-cured and released to form a resin layer 15 on which the grating mask pattern 31 was formed (FIG. 3B).
　フッ素系ガスによるドライエッチングにて樹脂マスクパターンをマスクとし、Tiからなるマスク材料層３を光学材料層２の表面までエッチングし、樹脂残りを除去した（図３（ｃ））。この上にフォトレジスト２０を塗布し（図４（ａ））、マスクアライナーにて、縦200μｍ、横200μｍの転写領域Ｂにおいてのみ、フォトレジスト（樹脂層）２１を残した。これを露光・現像し、所望の転写領域Ｂのパターンが点在したものとし、その上面にTiからなる保護層２２を50nm蒸着した（図４（ｃ））。 Using the resin mask pattern as a mask by dry etching with a fluorine-based gas, the mask material layer 3 made of Ti was etched to the surface of the optical material layer 2 to remove the resin residue (FIG. 3C). A photoresist 20 was applied thereon (FIG. 4A), and the photoresist (resin layer) 21 was left only in the transfer region B having a length of 200 μm and a width of 200 μm using a mask aligner. This was exposed and developed, and a pattern of a desired transfer region B was scattered, and a protective layer 22 made of Ti was deposited on the upper surface by 50 nm (FIG. 4C).
　次いで、有機溶剤によるリフトオフ法にてフォトレジスト上の保護層２２を除去し、縦200μm×横200μｍの転写領域Ｂにおいて、フッ素系ガスによるドライエッチングにてマスク部３２をマスクとし（図５（ａ））、光学材料層２を100nmの深さまでエッチングし、マスク部のTi残りを除去した（図５（ｃ））。 Subsequently, the protective layer 22 on the photoresist is removed by a lift-off method using an organic solvent, and the mask portion 32 is used as a mask by dry etching with a fluorine-based gas in a transfer region B of 200 μm in length × 200 μm in width (FIG. 5A )), The optical material layer 2 was etched to a depth of 100 nm, and the remaining Ti in the mask portion was removed (FIG. 5C).
　以上により、200nmピッチ・深さ100nm・ディーティ比1:1の転写領域（縦200μm×横200nm）Ｂが点在したパターン密度が小さいブラッググレーティング３４が形成された。このグレーティング部のみ、光学材料層の表面を基準として下方に凹部２６が有る形状となっている。 Thus, a Bragg grating 34 having a small pattern density dotted with transfer regions (200 μm long × 200 nm wide) B having a pitch of 200 nm, a depth of 100 nm, and a duty ratio of 1: 1 was formed. Only this grating portion has a shape having a concave portion 26 below the surface of the optical material layer.
　縦200μm×横200μmの領域内のピッチを、±0.04nm以下の高精度測定が可能なAFM及びレーザーによる回折光を用いた測定機により測定した結果、φ6インチウェハ面内全てにおいて、200±0.2nmの超高精度な所望ピッチが得られた。 As a result of measuring the pitch in the region of 200 μm in length × 200 μm in width with a measuring machine using diffracted light with AFM and laser capable of high accuracy measurement of ± 0.04 nm or less, it is 200 ± 0.2 in all φ 6 inch wafer surface. The desired pitch with ultra-high accuracy of nm was obtained.
（実施例２）
　図３、図４（ａ）（ｂ）および図６を参照しつつ説明した方法に従い、グレーティング素子を作製した。
　まず、実施例１と同様のモールド７を準備した。 (Example 2)
A grating element was fabricated according to the method described with reference to FIGS. 3, 4A, 4B, and 6. FIG.
First, the same mold 7 as in Example 1 was prepared.
　Φ6インチのSiからなる支持基板１上に、SiO2からなるクラッド層を1.0μm成膜し、その上面にTa2O5からなる光学材料層２を1.0μm成膜し、更にその上面にＴｉからなるマスク材料層３を50nmをスパッタにて成膜した。この上にナノインプリント樹脂４を塗布し、上記モールドをプレス・紫外線硬化させ、離型させて、グレーティングマスクパターン３１の形成された樹脂層１５を形成した。 On the support substrate 1 made of Φ6 inch Si, a cladding layer made of SiO2 is formed by 1.0 μm, an optical material layer 2 made of Ta2O5 is formed by 1.0 μm on the upper surface thereof, and a mask material made of Ti is further formed on the upper surface thereof. Layer 3 was deposited by sputtering at 50 nm. The nanoimprint resin 4 was applied thereon, the mold was pressed / ultraviolet cured, and released to form the resin layer 15 on which the grating mask pattern 31 was formed.
　フッ素系ガスによるドライエッチングにて樹脂マスクパターン１５をマスクとし、Tiからなるマスク材料層３を光学材料層２の表面までエッチングし、樹脂残りを除去した（図３（ｃ））。次いで、この上にフォトレジスト２０を塗布し、マスクアライナーにて転写領域Ｂ（縦200μm×横200nm）においてフォトレジストを残し、露光・現像をした。次いで、Tiエッチング薬液を使用し、フォトレジストで保護されていない部分のTiからなる非マスク部３３を除去し（図６（ａ））、次いで樹脂層２１を除去した（図６（ｂ））。 Using the resin mask pattern 15 as a mask by dry etching with fluorine-based gas, the mask material layer 3 made of Ti was etched to the surface of the optical material layer 2 to remove the resin residue (FIG. 3C). Next, a photoresist 20 was applied thereon, and the photoresist was left in the transfer region B (length 200 μm × width 200 nm) with a mask aligner, and was exposed and developed. Next, using a Ti etching chemical solution, the non-mask portion 33 made of Ti that is not protected by the photoresist is removed (FIG. 6A), and then the resin layer 21 is removed (FIG. 6B). .
　形成された転写領域Ｂ（縦200μm×横200nm）のTiからなるマスク部１８を利用し、フッ素系ガスによるドライエッチングにて、光学材料層２を100nmの深さまでエッチングし、Ti膜残りを除去した。 Using the formed mask area 18 made of Ti in the transfer area B (vertical 200 μm × width 200 nm), the optical material layer 2 is etched to a depth of 100 nm by dry etching with a fluorine-based gas, and the remaining Ti film is removed. did.
　以上により、200nmピッチ・深さ100nm・デューティ比1:1のブラッググレーティングパターン３６を、転写領域Ｂにおいて光学素子層２７に形成した。 Thus, a Bragg grating pattern 36 having a pitch of 200 nm, a depth of 100 nm, and a duty ratio of 1: 1 was formed on the optical element layer 27 in the transfer region B.
　転写領域Ｂ（縦200μm×横200nm）内のピッチ測定を±0.04nm以下の高精度測定が可能なAFM及びレーザーによる回折光を用いた測定機により実施した。この結果、φ6インチウェハ面内全てにおいて、200±0.2nmの超高精度な所望ピッチが得られた。 The pitch in the transfer region B (vertical 200 μm × width 200 nm) was measured by a measuring machine using AFM and laser diffracted light capable of high accuracy measurement of ± 0.04 nm or less. As a result, a desired pitch with an ultra-high accuracy of 200 ± 0.2 nm was obtained in the entire φ6 inch wafer surface.
　以上のように、本発明実施例１、２で形成したグレーティングのピッチは、いずれも200±0.2nmと所望の200±0.5nm以下となっていた。比較例においては、こうした小さい寸法の微細パターンは、高い転写精度で形成することはできなかった。 As described above, the pitches of the gratings formed in Examples 1 and 2 of the present invention were both 200 ± 0.2 nm and the desired 200 ± 0.5 nm or less. In the comparative example, such a fine pattern having a small dimension could not be formed with high transfer accuracy.

Claims (5)

  1. 　支持基板、
    　前記支持基板上に設けられた光学素子層、および
    　転写領域において前記光学素子層に形成された微細パターンを有する光学デバイスを製造する方法であって、
    　支持基板、光学材料層、マスク材料層および第一の樹脂層を備えるアセンブリに対して、前記微細パターンに対応する設計パターンの形成されたモールドを用いてインプリント法によって前記第一の樹脂層に前記設計パターンを転写し、前記マスク材料層をパターニングしてマスクパターン層を形成し、
    　次いで前記マスクパターン層のうち前記転写領域に対応するマスク部を被覆し、かつ前記マスク部以外の非マスク部を被覆しない第二の樹脂層を形成し、
    　このマスク部を介して前記光学材料層をエッチングすることによって、前記微細パターンを有する前記光学素子層を形成することを特徴とする、光学デバイスの製造方法。     Support substrate,
    An optical element layer provided on the support substrate, and a method of manufacturing an optical device having a fine pattern formed on the optical element layer in a transfer region,
    An assembly including a support substrate, an optical material layer, a mask material layer, and a first resin layer is formed on the first resin layer by an imprint method using a mold having a design pattern corresponding to the fine pattern. Transfer the design pattern, pattern the mask material layer to form a mask pattern layer,
    Next, a second resin layer that covers a mask portion corresponding to the transfer region in the mask pattern layer and does not cover a non-mask portion other than the mask portion is formed,
    A method of manufacturing an optical device, wherein the optical element layer having the fine pattern is formed by etching the optical material layer through the mask portion.
  2. 　前記第二の樹脂層および前記マスク部を被覆する保護層を設け、リフトオフ法によって前記第二の樹脂層を除去することで前記転写領域において前記マスク部を露出させ、この露出したマスク部を介して前記光学材料層をエッチングすることによって、前記微細パターンを有する前記光学素子層を形成することを特徴とする、請求項１記載の方法。 A protective layer is provided to cover the second resin layer and the mask portion, and the second resin layer is removed by a lift-off method to expose the mask portion in the transfer region, and through the exposed mask portion. The method according to claim 1, wherein the optical element layer having the fine pattern is formed by etching the optical material layer.
  3. 　前記マスクパターン層のうち前記第二の樹脂層によって被覆されていない前記非マスク部を除去し、次いで前記第二の樹脂層を除去することで前記転写領域において前記マスク部を露出させ、この露出したマスク部を介して前記光学材料層をエッチングすることによって、前記微細パターンを有する前記光学素子層を形成することを特徴とする、請求項１記載の方法。 The non-mask portion that is not covered with the second resin layer is removed from the mask pattern layer, and then the second resin layer is removed to expose the mask portion in the transfer region. The method according to claim 1, wherein the optical element layer having the fine pattern is formed by etching the optical material layer through the mask portion.
  4. 　前記微細パターンが、前記光学素子層の表面に周期的に形成された凹部からなることを特徴とする、請求項１～３のいずれか一つの請求項に記載の方法。 The method according to any one of claims 1 to 3, wherein the fine pattern includes concave portions periodically formed on a surface of the optical element layer.
  5. 　前記微細パターンがブラッググレーティングを構成することを特徴とする、請求項４記載の方法。 The method according to claim 4, wherein the fine pattern constitutes a Bragg grating.
PCT/JP2016/051846 2015-02-19 2016-01-22 Method for producing optical device WO2016132816A1 (en)

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JP2013201278A (en) * 2012-03-23 2013-10-03 Toshiba Corp Droplet arrangement method, pattern formation method, droplet arrangement program, droplet arrangement device, and pattern design method for template
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JP2007156446A (en) * 2005-11-08 2007-06-21 Nec Electronics Corp Method of forming pattern
JP2009098689A (en) * 2007-09-27 2009-05-07 Hoya Corp Mask blank and method for production of imprint mold
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