JP2004271857A - Electron beam lithography, manufacture method of matrix, matrix, manufacture method of die , die, optical element and electron beam lithography system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron beam lithography capable of performing correction of canceling working errors accumulated in other processes and plotting a diffraction structure by which a prescribed optical performance is obtained. <P>SOLUTION: A phase change of diffracted light due to shape error of the surface to be plotted of a base material is corrected by adjustment of an interval of the diffraction grating. Concretely, when the height of a curved surface part 100a of the base material 100 (film surface of resist applied on original optical surface of the base material) has an increasing tendency compared with the design data, the interval of a diffraction zone 300a of the part is adjusted so as to become narrower than the design data. Conversely, when the height of a curved surface part 100a of the base material 100 has a decreasing tendency, the interval of a diffraction zone 300a of the part is adjusted so as to become wider than the design data. Thereby, for example, a working error in a cutting work process (error of height dimension of the original optical surface of the base material 100) and a working error in a resist film forming process (error of film thickness of the resist applied on the original optical surface) are eliminated and, as a result, the diffraction structure capable of obtaining the prescribed optical performance can be plotted. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

（但し、δｐ＜＜ｐ）
となる。
また、曲面部１００ａ表面の高さ位置の規定値からの誤差ｄｔと回折光の位相変化との関係を（式２）で表すと、
Ｘ＝−（ｎ−１）ｄｔ／ｄｒ・・・・・・・・・・・（式２）
となる。
ここで、ｍ：回折光の次数、λ：光の波長、ｐ：回折格子の間隔の規定値、ｎ：屈折率、ｒ：基材１００の中心からの距離である。
【００８１】
これらの式から関係式を作成すると、
ｄｔ／ｄｒ＝ｍλ／−（ｎ−１）δｐ／ｐ^２・・・（式３）
となる。
【００８２】
さらに、（式３）から回折格子の間隔のズレ量δｐを導き出すと、
δｐ＝−（ｎ−１）ｐ^２／ｍλ×ｄｔ／ｄｒ・・・（式４）
となる。
【００８３】
即ち、パターン発生回路３０は、補正演算プログラム４０ｂに従って、曲面部１００ａ表面の高さ位置の規定値からの誤差ｄｔを算出して、これを（式３）に代入すると共に、（式４）により、回折格子の間隔の補正量δｐを算出する。
【００８４】
従って、例えば図１５（Ａ）に示すように、基材１００の任意のラインｒｎ（ｎ＝１、２、３…）におけるラジアル方向の位置ｒにおいて、曲面部１００ａ表面の高さ位置に規定値からの誤差ｄｔが生じている場合には、規定値から、（式４）にて算出されたδｐだけ、その位置の回折輪帯３００ａの間隔を増減させる調整を行えば、曲面部１００ａの形状誤差に起因する回折光の位相変化を補正することができる。
【００８５】
この際、例えば図１５（Ｂ）に示すように、基材１００の任意のラインｒｎにおけるラジアル方向の位置ｒにおいて、曲面部１００ａの高さ位置が規定値に対して大きくなる傾向にあれば、その部分の回折輪帯の間隔は規定値よりも狭く調整される。逆に、小さくなる傾向にあれば、その部分の回折輪帯の間隔は規定値よりも広く調整される。
【００８６】
このようにして調整された回折構造を描画することで、上述した切削加工工程における加工誤差（母光学面１１０ａの高さ位置の設計値からの誤差）と、レジスト膜形成工程における加工誤差（母光学面１１０ａに塗布されたレジストの膜厚の規定値からの誤差）を解消して、所定の光学的性能が得られる回折構造を描画することができる。
【００８７】
図２に戻って、このようにして、電子ビーム描画装置１にて描画後、３次元ステージ９より部材Ｅを取り外す（ステップＳ３１）。
【００８８】
［母型の製造方法 第３部］
続いて、母型の製造方法（第３部）について、図２に示すフローチャートの流れに沿って、図３を参照しつつ説明する。
【００８９】
＜現像工程＞
図２に示すように、さらに、不図示の現像装置によって、部材Ｅの現像処理を行って、輪帯形状のレジストを得る（ステップＳ３２）。尚、同一点における電子ビームの照射時間を長くすれば、それだけレジストの除去量は増大するため、上述した描画工程においては、電子ビームの照射位置と照射時間（ドーズ量）を調整することで、ブレーズの輪帯になるよう、レジストを残すことができる。
【００９０】
＜エッチング工程＞
さらに、不図示のエッチング装置によって、部材Ｅのエッチング処理を行って、母型の素材１１０の母光学面１１０ａの表面を彫り込んでブレーズ状の輪帯１１０ｂ（実際より誇張されて描かれている）を形成する（図３（ｅ）参照）（ステップＳ３３）。
【００９１】
ここまでの工程により、部材Ｅは母型として完成される。
【００９２】
［金型の製造方法］
次に、金型の製造方法について、図２に示すフローチャートの流れに沿って、図３を参照しつつ説明する。
【００９３】
＜電鋳工程＞
図２に示すように、さらに、スルファミン酸ニッケル浴中に、表面を活性処理した母型、即ち、部材Ｅを浸し、基材１１１と外部の電極１１４との間に電流を流すことで、電鋳１２０を成長させる（図３（ｆ）参照）（ステップＳ３４）。このとき、基材１１１の外周面１１１ｆに絶縁剤を塗布することで、絶縁剤が塗布された部分の電鋳形成を抑制できる。電鋳１２０は、その成長の過程で、母光学面１１０ａに精度良く対応した光学面転写面１２０ａと、輪帯１１０ｂに精度良く対応した輪帯転写面１２０ｂとを形成する。
【００９４】
その後、不図示のコンピュータに構築されているデータベースを、処理中の部材Ｅに対応するヤトイ１５０のＩＤ番号ＮＸに基づいて検索し、得られた（即ち、切削加工工程で使用された）ヤトイ１５０を、所定の取り付け条件で部材Ｅ（基材１１１）に取り付ける（ステップＳ３５）。この所定の取り付け条件とは、第１の工程の取り付け条件であり、具体的には、合マークＭＸを合致させ基材１１１とヤトイ１５０との位相を合わせること、読み出した締め付け時作業環境温度（第１の工程時の作業環境温度）に対して±１．０度の作業環境温度とすること、読み出した締め付けトルク（切削加工工程時の締め付けトルク）で締め付けを行うこと、同じボルト１５２を用いて取り付けることをいう。
【００９５】
さらに、不図示のコンピュータに構築されているデータベースに記憶された、処理中の部材Ｅの切削時作業環境温度にした上で、基材１１１の外周面１１１ｆを基準として、部材Ｅと電鋳１２０とヤトイ１５０とを一体で、ＳＰＤＴ加工機の回転軸と部材Ｅの光軸とを一致させるようにしてチャックに取り付け、電鋳１２０の外周面１２０ｃを切削加工する（図３（ｇ）参照）（ステップＳ３６）。
【００９６】
加えて、図３（ｇ）に示すように、電鋳１２０に、裏打ち部材との位置決め部としてのピン孔１２０ｄ（中央）及びネジ孔１２０ｅを加工する。尚、ピン孔１２０ｄの代わりに円筒軸を形成しても良い。加工後に、部材Ｅと電鋳１２０とヤトイ１５０とを一体で、ＳＰＤＴ加工機から取り外す。
【００９７】
さらに、電鋳１２０を、以下に述べるように裏打ち部材と一体化することで、可動コア１３０を形成する（ステップＳ３７）。
【００９８】
図１６は、部材Ｅを取り付けた状態で示す可動コア１３０の断面図である。図１６において、可動コア１３０は、先端（図で右側）に配置した電鋳１２０と、後端（図で左側）に配置した押圧部１３６と、その間に配置された摺動部材１３５とから構成される。摺動部材１３５及び押圧部１３６が裏打ち部材となる。
【００９９】
電鋳１２０は、そのピン孔１２０ｄに、円筒状の摺動部材１３５の端面中央から突出したピン部１３５ａを係合させることで、摺動部材１３５と所定の関係で位置決めされ、さらに、摺動部材１３５を軸線に平行に貫通する２つのボルト孔１３５ｂに挿通したボルト１３７を、ネジ孔１２０ｅに螺合させることで、電鋳１２０は摺動部材１３５に取り付けられる。
【０１００】
摺動部材１３５は、ピン部１３５ａの設けられた端面（図で右端）に対向する端面（図で左端）の中央に突出して形成されたネジ軸１３５ｃを、略円筒状の押圧部１３６の端部に形成されたネジ孔１３６ａに螺合させることで、押圧部１３６に対して所定の位置関係で取り付けられる。図１６において、摺動部材１３５の外周面１３５ｅは、電鋳１２０及び押圧部１３６のフランジ部１３６ｂ以外の部分の外周面よりも大径となっている。裏打ち部材としての摺動部材１３５及び押圧部１３６を取り付けた後、ＳＰＤＴ加工機のチャックにヤトイ１５０を取り付けるようにする（ステップＳ３８）。
【０１０１】
さらに、不図示のコンピュータに構築されているデータベースから、処理中の部材Ｅの切削時作業環境温度にした上で、基材１１１の外周面１１１ｆを基準として、摺動部材１３５と押圧部１３６の外周面を仕上げる（ステップＳ３９）。このため、ヤトイ１５０を基材１１１より一旦取り外したにもかかわらず、母型１１０の同心円パターン（輪帯１１０ｂ）中心と、金型摺動部外形中心との同軸度を１μｍ以内に収めることができる。さらに、押圧部１３６の端面を切削加工し、全長を規定値に収める（ステップＳ４０）。
【０１０２】
その後、図１６の矢印Ｘで示す位置でカットすることにより、摺動部材１３５及び押圧部１３６に取り付けられた電鋳１２０から、部材Ｅとヤトイ１５０を脱型する（ステップＳ４１）。さらに、電鋳１２０と基材２１０を脱型後、可動コア１３０の先端の電鋳１２０を仕上げて、光学素子成形用金型を得る（ステップＳ４２）。
【０１０３】
ここまでの工程により。光学素子成形用金型が製作される。
【０１０４】
［光学素子の製造］
図１７は、このようにして形成された可動コア１３０を用いて光学素子を成形する状態を示す図である。図１７において、光学面転写面１４１ａを有する光学素子成形用金型１４１を保持する保持部１４２は、可動側キャビティ１４３に固定されている。可動側キャビティ１４３は、小開口１４３ａと、それに同軸な大開口１４３ｂとを有している。可動側キャビティ１４３内に可動コア１３０を挿入したときに、摺動部材１３５の外周面１３５ｅが、小開口１４３ａの内周面と摺動し、押圧部１３６のフランジ部１３６ｂの外周面１３６ｄが、大開口１４３ｂの内周面と摺動する。かかる２つの摺動部によって案内されることで、可動側キャビティ１４３に対して、大きく傾くことなく可動コア１３０は軸線方向に移動可能となる。
【０１０５】
光学素子成形用金型１４１、電鋳１２０の間に溶融した樹脂を射出し、可動コア１３０を矢印方向に加圧することで、光学素子ＯＥが成形される。本実施の形態によれば、母型の素材１１０から精度良く転写形成された光学素子成形用金型としての電鋳１２０を用いることで、光学素子ＯＥの光学面には、電鋳１２０の光学面転写面１２０ａが転写形成され、且つ、輪帯転写面１２０ｂに対応した回折輪帯が光軸に同心的に精度よく形成されることとなる。
【０１０６】
ここまでの工程により。光学素子が製作される。
【０１０７】
尚、以上のようにして光学素子成形用金型を加工する場合、電鋳１２０に、第２のマーク１１１ｂに対応する突起（不図示）が転写形成されているため、これを加工の基準として用いることで、その外周面等の精度の良い加工を行うこともできる。
【０１０８】
以上に説明したように、本実施の形態における電子ビーム描画方法によれば、切削加工工程やレジスト膜形成工程において蓄積された加工誤差を解消する補正を行って、所定の光学的性能が得られる回折構造を描画することができる。
【０１０９】
尚、本発明に係る基材の描画方法、及び電子ビーム描画装置ついては、その特定の実施の形態に従って説明してきたが、当業者は、本発明の主旨および範囲から逸脱することなく本発明の本文に記述した実施の形態に対して種々の変形が可能である。
【０１１０】
例えば、形状測定器２００や膜厚測定器からの測定情報は、電子ビーム描画装置１の測定情報入力部１５８から入力される他、制御回路２０と接続される不図示のネットワークを介してデータ転送されて、メモリ３９などに格納されることにしても良い。
【０１１１】
また、部材Ｅの形状測定、即ち、母型の素材１１０の母光学面１１０ａの３次元座標の測定は、形状測定器２００によらず、電子ビーム描画装置１の測定器１１によって行うことにしても良い。
【０１１２】
また、部材Ｅの形状測定後に、直ちに電子ビーム描画装置１により描画を行って、母型の素材１１０の母光学面１１０ａの高さ位置の誤差を補正することにしても良い。
【０１１３】
また、部材Ｅの形状測定を行わず、部材Ｅにレジストを塗布した後、レジスト膜の膜厚測定のみを行って、母型の素材１１０の母光学面１１０ａの高さ位置の誤差を補正することにしても良い。
【０１１４】
【発明の効果】
以上説明したように、本発明に係る電子ビーム描画方法によれば、他の工程において蓄積した加工誤差を解消する補正を行って、所定の光学的性能が得られる回折構造を描画することができる。
【図面の簡単な説明】
【図１】本実施の形態における母型の製造方法、電子ビーム描画方法及び金型の製造方法を構成する工程を示すフローチャートである。
【図２】本実施の形態における母型の製造方法、電子ビーム描画方法及び金型の製造方法を構成する工程を示すフローチャートである。
【図３】図１及び図２に示す主要な工程において、処理される母型の素材と電極部材の組立体、即ち、部材Ｅを示す断面図である。
【図４】ヤトイを取り付けた部材Ｅの斜視図である。
【図５】図４に示す部材Ｅの上面図である。
【図６】形状測定器の全体構成を示す説明図である。
【図７】電子ビーム描画装置の全体構成を示す説明図である。
【図８】電子ビームのビームウエストを説明するための説明図である。
【図９】測定装置の全体構成を説明するための説明図である。
【図１０】測定装置の測定原理を説明するための説明図である。
【図１１】信号出力と基材の高さとの関係を示す特性図である。
【図１２】同図（Ａ）（Ｂ）は、電子ビーム描画装置により描画される基材を示す説明図であり、同図（Ｃ）は、電子ビーム描画装置の描画原理を説明するための説明図である。
【図１３】電子ビーム描画装置の制御系の構成を示す説明図である。
【図１４】基材に描画される回折構造を構成する回折輪帯の隣接する間隔が調整される過程を説明するための説明図である。
【図１５】基材の曲面部（被描画面）の形状誤差と回折輪帯の隣接する間隔の補正量との関係を説明するための説明図である。
【図１６】可動コアの断面図である。
【図１７】可動コアを用いて光学素子を成形する状態を示す図である。
【符号の説明】
１００ 基材
１００ａ 曲面部
１００ｂ 平坦部
３００ａ 回折輪帯
ｐ 回折輪帯の間隔の規定値
δｐ 回折輪帯の間隔の補正値
ｄｔ 曲面部の高さ位置の誤差
ｒ ラジアル方向における位置[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a drawing technique using an electron beam, and more particularly to a technique for drawing a predetermined pattern, for example, a diffraction pattern corresponding to an optical element, on a substrate to be drawn.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, CDs, DVDs, and the like have been widely used as information recording media, and many optical elements have been used in precision equipment such as a reading device that reads information from these recording media.
[0003]
In recent years, the specifications and performance required for these optical elements have been improved. In particular, in a pickup lens for a recording medium such as a DVD, a diffraction structure with higher accuracy is formed as the recording density increases. Is required. Specifically, processing accuracy at a level smaller than the wavelength of light, for example, at the nm level is required.
[0004]
By the way, these optical elements, for example, an optical lens, often use a resin optical lens rather than a glass optical lens from the viewpoint of cost reduction and miniaturization. It is manufactured by general injection molding.
[0005]
Therefore, for example, when manufacturing an optical element having a diffractive structure or the like on the optical function surface, a mold for injection molding this optical element is formed in advance with a surface for providing such a diffractive structure. Need to be kept.
[0006]
Until now, molding dies have been processed by cutting tools of general molding and processing techniques.However, when trying to form fine shapes such as diffractive structures, the processing accuracy is poor and the strength and There is a limit in the service life, and it is difficult to perform precise processing on the order of submicron or less.
[0007]
Therefore, a fine shape such as a diffractive structure is drawn on a base material to be a master, and then developed to form a fine shape to obtain a master, and this master is used. An attempt has been made to obtain a mold by transferring and forming a fine shape on a mold by performing electroforming (see, for example, Patent Document 1).
[0008]
[Patent Document 1]
JP 2002-333722 A
(Paragraph [0161]-[0170], Fig. 13)
[Problems to be solved by the invention]
[0009]
However, in such a manufacturing process, a cutting process for obtaining a base material by cutting a material and a resist for forming a resist film on the base material have been conventionally required, whereas a cutting process is only required. A film forming step, a drawing step of drawing a fine shape on a resist film on a base material, a developing step of developing the same, an etching step of etching the same to obtain a matrix, and electroforming using the matrix. Is required, and the number of steps increases from one to six or more.
[0010]
However, when the number of steps increases in this way, machining errors in each step accumulate, and the total error is represented by the following equation.
Total error = sqrt (p1 ² + P2 ² + P3 ² + ... + p6 ² ＋ ・ ・ ・)
(Pn: error in n steps)
[0011]
By the way, comparing the case where the number of steps is 1 and the case where the number of steps is 6, when the number of steps is 6, in order to maintain the same total error as the case where the number of steps is 1, it is necessary to perform each step. The required processing accuracy is 1/2 to 1/3 of the conventional one.
[0012]
However, in the case of an optical element such as an OD lens, in the drawing step, processing accuracy within a level of several tens of nm is required for a design value, and it is extremely difficult to achieve higher accuracy. Goals.
[0013]
Therefore, in order to eliminate the accumulation of processing errors due to the increase in the number of steps, it is necessary to correct the errors in any of the steps.
[0014]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a diffraction structure that performs a correction to eliminate a processing error accumulated in another process to obtain a predetermined optical performance. An object of the present invention is to provide an electron beam writing method capable of writing.
[0015]
[Means for Solving the Problems]
To achieve the above object, the invention according to claim 1 is an electron beam drawing method for drawing a predetermined diffraction structure on the base material by scanning the base material with an electron beam, A shape measurement step of measuring an error from a specified value of the height distribution of the surface of the base material, and according to an error from the specified value of the height distribution, corresponding to each diffraction grating constituting the diffraction structure. In order to correct the phase change due to the error of the diffracted light, a drawing adjustment step of adjusting the interval between the individual diffraction gratings, and scanning the electron beam according to the adjusted interval to draw the individual diffraction gratings And a writing step of performing
[0016]
In order to achieve the above object, the invention according to claim 3 is an electron beam drawing method for drawing a predetermined diffraction structure on the base material by scanning the base material with an electron beam, A film thickness measuring step of measuring an error from a specified value of the film thickness distribution of the resist film formed on the base material, and forming the diffraction structure according to the error from the specified value of the film thickness distribution. In order to correct the phase change due to the error of the diffracted light corresponding to the diffraction grating, a drawing adjustment step of adjusting the interval between the individual diffraction gratings, and scanning the electron beam according to the adjusted interval, And a drawing step of drawing individual diffraction gratings.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings. In the following, a method for manufacturing a master mold, an electron beam lithography method, an electron beam lithography apparatus, a method for manufacturing a metal mold, and an optical element will be described in the order along the flow until an optical element is obtained.
[0018]
[Manufacturing Method of Matrix Part 1]
First, a method of manufacturing a mother die (first part) will be described with reference to FIG. 3 along the flow of the flowchart shown in FIG.
[0019]
<Cutting process>
As shown in FIG. ₂ A matrix material 110 having a substantially hemispherical shape made of a resin material such as polysilicon or polyolefin is embedded in a central opening 111p of a disk-shaped base material 111 made of a conductive material such as a metal, and an adhesive is used. The member E is fixed so as not to rotate relatively (see FIG. 3A), and a member E is obtained (step S01). Note that the member E corresponds to the “base material” of the present invention. Next, the toy 150 is attached to the base 111 by bolts 152 which are penetrated through a central hole 151 of a jig (hereinafter referred to as a toy) 150 and are screwed into screw holes 111g of the base 111. Then, the combination mark MX and the ID number NX are given to the base material 111 (step S02). As shown in FIG. 4, the ID number NX is a number assigned to each of the attached toys 150, and functions as information for specifying the same. In the present example, the ID number NX is engraved by laser drawing in the groove 111h obtained by cutting the outer peripheral surface of the base material 111 in a tangentially narrow plane, but printing may be performed. Further, the groove may be an entire circumferential groove having the same depth. Also, the alignment mark MX for adjusting the phase with the base material 111 can be engraved by laser processing.
[0020]
Next, in the process management database constructed in the computer (not shown), the ID number NX of the yatoy, the mounting surface (direction), the tightening torque, the working environment temperature (ambient temperature), etc. are associated with this member E. Is stored (step S03). Thereafter, the member E is attached to the chuck of an unillustrated ultra-precision lathe (SPDT processing machine) via the toy 150 (step S04). Furthermore, since the member E is not rotated, the outer peripheral surface 111f of the base material 111 is cut with a diamond tool to thereby provide a high-precision lathe, for example, an SPDT (Single Point Diamond Turning) machine with high precision with respect to the rotation axis. Then, the upper surface of the base material 110 is cut as shown in FIG. 3B to form a base optical surface (corresponding to the optical curved surface of the optical element to be molded) 110a, and A peripheral groove 111a (first mark) is cut on the upper surface of the base material 111 (step S05). At this time, the feed amount and the cut amount are controlled while performing the temperature control to obtain a surface roughness of 50 nm to 20 nm of the curved surface. At this time, the position of the optical axis of the mother optical surface 110a cannot be confirmed from its outer shape, but since it is processed at the same time, the mother optical surface 110a and the circumferential groove 111a are formed coaxially with high precision. That is, the outer peripheral surface 111f of the base material 111 formed on the cylindrical surface is also formed coaxially with the optical axis with high precision. Here, the peripheral groove 111a may be formed of, for example, a plurality of grooves including a dark field portion (corresponding to a concave portion) and a bright field portion (corresponding to a convex portion). It is more preferable to have a diamond tool (this can be easily formed if the tip of the diamond tool has irregularities). Further, the concave and convex shape of the peripheral groove 111a can function as a dike for preventing the scattering of the resist applied as described later.
[0021]
Further, the working environment temperature at the time of cutting of the member E is stored in a process management database constructed on a computer (not shown), and the member E is removed from the SPDT processing machine (step S06). The toy 150 is removed from the device (step S07). Then, the processing mark (tool mark) of the diamond tool which looks rainbow-colored visually is polished and polished until the rainbow-colored color disappears. Further, the member E is set on a stage of a not-shown FIB (Focused Ion Beam) processing machine (step S08). Next, the circumferential groove 111a in the member E on the stage of the FIB processing machine is read, and the position of the optical axis of the base material 110 is determined from the inner edge thereof (step S09), and is equidistant from the determined optical axis. Three (or more than four) second marks 111b are drawn on the base material 111 (see FIGS. 3B and 5) (step S10). Since the width of the peripheral groove 111a formed by the diamond tool is relatively wide, using it as a reference for processing may reduce the processing accuracy. However, the FIB processing machine has an accuracy of about 20 nm in width. For example, when a cross line is formed, a fine mark of 20 nm × 20 nm can be formed, and by using this as a reference for processing, more accurate processing can be performed. Next, the member E is removed from the stage of the FIB processing machine (step S11).
[0022]
[Electron Beam Writing Method Part 1]
Next, the electron beam writing method (first part) will be described with reference to FIG. 3 along the flow of the flowchart shown in FIG.
[0023]
<Shape measurement process>
As shown in FIG. 1, subsequently, the member E is set on a shape measuring device (having an image recognizing means and a storage means) which will be described later (step S12). Is detected (step S13). Further, the three-dimensional coordinates of the mother optical surface 110a of the master material 110 obtained by the measurement or used in the ultra-precision lathe are converted into three-dimensional coordinates based on the second mark 111b. From the three-dimensional coordinates based on the second mark 111b, a specified value relating to the height position of the mother optical surface 110a of the master material 110, that is, error distribution data from the design value is created, and these are stored in the storage means. (Step S14). As described above, the reason why the mother optical surface 110a is stored again with the new three-dimensional coordinates is that the electron beam drawing depth of the electron beam with respect to the drawing surface of the mother optical surface 110a when performing electron beam drawing in a drawing process described later. This is because it is necessary to adjust the relative position between the electron gun and the member E in order to match. Note that the second mark 111b can be used as a mark for position recognition so that an operator can visually recognize the reference point of the coordinates related to the measurement data during measurement. Thereafter, the member E is removed from the shape measuring instrument (Step S15).
[0024]
(Shape measuring instrument)
Here, the shape measuring device will be described with reference to FIG.
[0025]
As shown in FIG. 6, the measuring device 200 includes a first laser length measuring device 201, a second laser length measuring device 202, a pinhole 205, a pinhole 206, a first light receiving section 203, and a second light receiving section. 204, and further includes a measurement calculation unit (not shown) for calculating these measurement results, a storage unit for storing the measurement results, and control means (not shown) having various control systems.
[0026]
In such a configuration, the first laser beam length measuring device 201 irradiates the member E with the first light beam S1 and reflects the first light beam S1 reflected by the flat portion 110b of the matrix die material 110. The light is received by the first light receiving unit 203 via the pinhole 205, and the first light intensity distribution is detected.
[0027]
At this time, since the first light beam S1 is reflected on the flat portion 110b of the matrix material 110, the first light beam S1 is reflected on the flat portion 110b of the matrix material 110 based on the first intensity distribution. ) The position is measured and calculated.
[0028]
Further, a second light beam S2 is emitted from the second laser length measuring device 202 to the member E from a direction different from the first light beam S1, and the second light beam S2 is transmitted through the mother optical surface 110a of the master mold material 110. Is received by the second light receiving unit 204 via the pinhole 206, and the second light intensity distribution is detected.
[0029]
In this case, since the second light beam S2 passes through the mother optical surface 110a of the matrix material 110, the mother light projecting from the flat portion of the matrix material 110 based on the second intensity distribution. The (height) position on the optical surface 110a is measured and calculated. The principle of measurement and calculation of the (height) position on the mother optical surface 110a of the master mold material 110 will be described later in the description of a measuring device of an electron beam writing apparatus.
[0030]
[Manufacturing method of mother die Part 2]
Next, a method of manufacturing the mother die (second part) will be described with reference to FIG. 3 along the flow of the flowcharts shown in FIGS.
[0031]
<Resist film formation process>
Returning to FIG. 1, next, the protective tape 113 is stuck on the second mark 111b (see FIG. 3C) (step S16). This protective tape 113 is for preventing the resist L applied on the base material 110 in the post-processing from adhering to the second mark 111b. This is because if the resist L adheres to the second mark 111b, reading becomes inappropriate as a processing reference. The protection by the protection tape is shown in FIG. 3C and shows a case where only one second mark 111b is protected. However, the same applies to the other second marks 111b. Further, the member E is set on a spin coater (not shown) (step S17), and a press pin for rotating the substrate to be coated with the resist L while flowing the resist L onto the base material 110 is performed (step S18). The spin of the resist-coated substrate is stopped by stopping the flow of the resist L, and the resist L is coated (see FIG. 3D) (step S19). By separating the press pin from the main spin, it is possible to coat the resist L having a uniform thickness on the mother optical surface 110a, which is a complicated curved surface. Here, the resist L is made of a polymer resin material that is cured by heating or ultraviolet rays, and has a property that bonds between molecules are cut and decomposed according to the amount of energy given by the electron beam. (Decomposed portions are removed by a developer described later).
[0032]
Thereafter, the member E is removed from the spin coater (Step S20), and the member E is baked (heated) to stabilize the film of the resist L (Step S21). The temperature at this time is about 170 ° C., and heating is performed for about 20 minutes. Further, the protective tape 113 is peeled off (Step S22). The member E in such a state is shown in FIG.
[0033]
[Electron Beam Writing Method Part 2]
Next, the electron beam writing method (second part) will be described with reference to FIG. 3 along the flow of the flowchart shown in FIG.
[0034]
<Film thickness measurement step>
As shown in FIG. 2, the member E is further set on a film thickness measuring device (not shown) (having an image recognizing means and a storage means) (step S23), and using the image recognizing means of the film thickness measuring device, The second mark 111b is detected (Step S24). Further, the film thickness distribution of the resist L applied to the mother optical surface 110a of the matrix material 110 is converted into a film thickness distribution based on the second mark 1011b, and further, a film based on the second mark 111b. From the thickness distribution, a specified value, that is, error distribution data from the thickness value to be obtained is created, and these are stored in the storage means (step S25). In this way, by creating error distribution data from the prescribed value of the film thickness of the resist L based on the second mark 111b, the error distribution data is converted into the mother optical surface 110a of the master mold material 110 by the above-described shape measuring instrument. Can be associated with the error distribution data from the design value of the height position. Thereafter, the member E is removed from the film thickness measuring device (Step S26).
[0035]
<Drawing adjustment process>
Further, the member E is set on a three-dimensional stage of an electron beam writing apparatus to be described later (step S27), and is connected via a measuring instrument (scanning electron microscope (SEM): preferably attached to the electron beam writing apparatus). The second mark 111b of the member E is detected (step S28), the detection result and measurement information from the shape measuring device 200 and the film thickness measuring device input from the input unit, specifically, the shape of the member E From the data, that is, the three-dimensional coordinates of the mother optical surface 110a and the film thickness distribution of the resist L applied to the mother optical surface 110a, the shape of the drawing surface (the resist L film surface) of the mother optical surface 110a is obtained. Further, based on each error distribution data (error distribution data from the design value of the height position of the base optical surface 110a, error distribution data from the specified value of the film thickness of the resist L applied to the base optical surface 110a) There are, to create the shape data for a given drawing pattern to be drawn in the drawing surface of the mother optical surface 110a (step S29). The details of the drawing adjustment step will be described later (details of the drawing adjustment step).
[0036]
<Drawing process>
Further, in order to draw a predetermined drawing pattern on the obtained shape of the drawing surface, the three-dimensional stage is moved so that the electron beam is focused on the drawing surface, and the electron beam (see FIG. 3D) is moved. Irradiation is performed so as to have a predetermined dose, and a predetermined drawing pattern, for example, an individual diffraction grating corresponding to the diffraction structure, for example, a diffraction ring zone is drawn on the resist L film on the mother optical surface 110a (step S30). At this time, the interval between adjacent diffraction zones is determined by the error distribution from the design value of the height position of the mother optical surface 110a and the error distribution from the specified value of the film thickness of the resist L applied to the mother optical surface 110a. It is adjusted based on.
[0037]
(Configuration of drawing apparatus)
Here, the overall configuration of the electron beam writing apparatus will be described with reference to FIG. In the following, it is assumed that the member E in which the resist L film is formed on the mother optical surface 110 a of the matrix material 110 corresponds to the base material 100.
[0038]
As shown in FIG. 7, the electron beam writing apparatus 1 forms a high-resolution electron beam probe with a large current and scans the substrate 100 to be written at a high speed. An electron gun 2 that is formed, generates an electron beam, and irradiates the target with a beam, a slit 3 that allows the electron beam from the electron gun 2 to pass, and a focus of the electron beam that passes through the slit 3 with respect to the substrate 100. An electron lens 4 for controlling the position, an aperture 5 disposed on a path from which the electron beam is emitted, and a deflection for controlling a scanning position on the base material 100 as a target by deflecting the electron beam. And a correction coil 7 for correcting deflection. These components are arranged in the lens barrel 8 and are kept in a vacuum state when the electron beam is emitted. Note that the electron gun 2 corresponds to the “electron beam irradiation unit” of the present invention. Further, the deflector 6 corresponds to “scanning means” of the present invention.
[0039]
Further, the electron beam writing apparatus 1 includes an XYZ stage 9 serving as a mounting table for mounting the substrate 100 on which an image is to be written, and a transport for transporting the substrate 100 to a mounting position on the XYZ stage 9. A loader 10 as a means, a measuring device 11 as a measuring means for measuring a reference point on the surface of the substrate 100 on the XYZ stage 9, and a stage driving device 12 as a driving means for driving the XYZ stage 9 A loader driving device 13 for driving the loader; a vacuum exhaust device 15 for exhausting the inside of the lens barrel 8 and the housing 14 including the XYZ stage 9 so as to be evacuated; and control means for controlling these components And a control circuit 20.
[0040]
The electronic lens 4 is controlled by generating a plurality of electronic lenses by the current value of each of the coils 4a, 4b, and 4c that are separately installed at a plurality of locations along the height direction, The focal position of the electron beam is controlled.
[0041]
The measuring device 11 is a laser measuring device 11a that measures the substrate 100 by irradiating the substrate 100 with a laser, and the laser light emitted from the laser measuring device 11a reflects the substrate 100 to reflect the laser light. And a light receiving section 11b for receiving the reflected light. The details will be described later.
[0042]
The stage driving device 12 includes an X-direction driving mechanism for driving the XYZ stage 9 in the X direction, a Y-direction driving mechanism for driving in the Y direction, a Z-direction driving mechanism for driving in the Z direction (the traveling direction of the electron beam), and a θ-direction driving mechanism that drives in the θ-direction. Thereby, the XYZ stage 9 can be operated three-dimensionally and alignment can be performed.
[0043]
The control circuit 20 includes an electron gun power supply unit 21 for supplying power to the electron gun 2, an electron gun control unit 22 for adjusting and controlling current, voltage, and the like in the electron gun power supply unit 21, and an electronic lens 4 (a plurality of And a lens control unit 24 for adjusting and controlling each current corresponding to each electronic lens in the lens power supply unit 23. .
[0044]
Further, the control circuit 20 includes a coil controller 25 for controlling the correction coil 7 and a deflecting unit for deflecting in the forming direction by the deflector 6 and for deflecting in the main scanning direction and the sub-scanning direction. 26, and a D / A converter 27 that converts and controls a digital signal into an analog signal in order to control the deflection unit 26.
[0045]
Further, the control circuit 20 corrects a position error in the deflector 6, that is, supplies a position error correction signal or the like to the D / A converter 27 to urge the position error correction, or prompts the coil control unit 25 to correct the position error. By supplying the signal to the correction circuit 7, a position error correction circuit 28 for correcting a position error by the correction coil 7, and the position error correction circuit 28 and the D / A converter 27 are controlled to reduce the electric field of the electron beam. An electric field control circuit 29 as electric field control means for controlling, and a pattern generation circuit 30 for generating a drawing pattern or the like corresponding to the substrate 100 are configured.
[0046]
Further, the control circuit 20 includes a laser drive control circuit 31 for moving the laser irradiation position by moving the laser length measurement device 11a up and down, left and right, and driving control of the angle of the laser irradiation angle, and the like. A laser output control circuit 32 for adjusting and controlling the output (laser light intensity) of the laser irradiation light, and a measurement calculation unit 33 for calculating a measurement result based on a light reception result in the light receiving unit 11b. Be composed.
[0047]
Further, the control circuit 20 includes a stage control circuit 34 for controlling the stage drive device 12, a loader control circuit 35 for controlling the loader drive device 13, the above-described laser drive circuit 31, laser output control circuit 32, A mechanism control circuit 36 for controlling the section 33, a stage control circuit 34, and a loader control circuit 35; a vacuum exhaust control circuit 37 for controlling the vacuum exhaust of the vacuum exhaust device 15; A measurement information input unit 38 for inputting measurement information, a memory 39 serving as a storage unit for storing the input measurement information and other information, and a program memory 40 storing a control program for performing various controls And a control unit 41 configured by, for example, a CPU or the like which controls these units. Note that the measurement information input unit 38 corresponds to the “shape information obtaining unit” and the “film thickness information obtaining unit” of the present invention.
[0048]
(Drawing process)
In the electron beam lithography apparatus 1 having such a configuration, when the substrate 100 conveyed by the loader 10 is placed on the XYZ stage 9, the air in the lens barrel 8 and the housing 14 is removed by the vacuum exhaust device 15. After exhausting dust and the like, the electron gun 2 emits an electron beam.
[0049]
The electron beam emitted from the electron gun 2 is deflected by a deflector 6 through an electron lens 4 and is deflected by an electron beam B (hereinafter, only the deflection-controlled electron beam after passing through the electron lens 4 is referred to as " The electron beam B is sometimes referred to as “electron beam B”), and the drawing is performed by irradiating the surface of the substrate 100 on the XYZ stage 9, for example, the drawing position on the curved surface portion (curved surface) 100.
[0050]
At this time, the measuring device 11 measures the drawing position on the base material 100 (at least the height position among the drawing positions) or the position of a reference point as described later. Based on this, the current values flowing through the coils 4a, 4b, 4c and the like of the electronic lens 4 are adjusted and controlled to control the focus position of the electron beam B, and the movement is controlled so that the focus position becomes the drawing position. .
[0051]
As shown in FIG. 8, the electron beam has a deep depth of focus FZ, but the electron beam B narrowed down to the width D of the electron lens 4 has a beam waist BW having a substantially constant thickness. The length of the range of the beam waist BW in the electron beam traveling direction corresponds to the depth of focus FZ here. The focal position is a position of the beam waist BW in the electron beam advancing direction, and here is a center position of the beam waist BW in the electron beam advancing direction.
[0052]
Alternatively, based on the measurement result, the control circuit 20 controls the stage driving device 12 to move the XYZ stage 9 so that the focal position of the electron beam B becomes the drawing position.
[0053]
The relative movement control between the base 100 and the focal position of the electron beam B can be performed by controlling either the control of the focal position of the electron beam B or the control of the XYZ stage 9 or by using both of them. However, when adjusting the electron lens 4 in controlling the electron beam B, it is necessary to correct an error due to a change in the deflection of the electron beam B. Therefore, it is preferable to perform the adjustment by controlling the movement of the XYZ stage 9.
[0054]
(measuring device)
Here, the measuring device 11 will be described with reference to FIG. As shown in FIG. 9, the measuring device 11 more specifically configures a first laser length measuring device 11aa and a second laser length measuring device 11ab configuring the laser length measuring device 11a, and a light receiving section 11b. It has a first light receiving unit 11ba, a second light receiving unit 11bb, and the like.
[0055]
In such a configuration, the first laser beam is emitted from the first laser length measuring device 11aa to the substrate 100 in a direction crossing the electron beam, and the first light beam S1 is reflected by the flat portion 100b of the substrate 100. The first light intensity distribution is detected by receiving the one light beam S1.
[0056]
At this time, since the first light beam S1 is reflected by the flat portion 100b of the base material 100, the (height) position on the flat portion 100b of the base material 100 is measured based on the first intensity distribution. It will be calculated. Here, the height position indicates the position in the Z direction, ie, the traveling direction of the electron beam B.
[0057]
Further, the second laser length measuring device 11ab irradiates the substrate 100 with the second light beam S2 from a direction substantially orthogonal to the electron beam different from the first light beam S1, and transmits the second light beam S2 through the substrate 100. The second light intensity distribution is detected by receiving the second light beam S2 via the pinhole 11c included in the second light receiving unit 11bb.
[0058]
In this case, as shown in FIGS. 10A to 10C, since the second light beam S2 passes through the curved surface portion 100a of the base material 100, the second light beam S2 is based on the second intensity distribution. The (height) position on the curved surface portion 100a protruding from the flat portion 100b of the material 100 is measured and calculated.
[0059]
More specifically, as shown in FIGS. 10A to 10C, the second light beam S2 passes through a specific height at a certain position (x, y) on the curved surface portion 100a in the XY reference coordinate system. Then, at this position (x, y), the second light beam S2 impinges on the curved surface of the curved surface portion 100a to generate scattered lights SS1 and SS2, and the light intensity of the scattered light is weakened. In this way, the (height) position on the curved surface 100a is measured and calculated based on the second light intensity distribution detected by the second light receiving unit 11bb.
[0060]
In this calculation, the signal output of the second light receiving unit 11bb has a correlation between the signal output Op and the height of the base material 100 as shown in the characteristic diagram of FIG. By storing in advance a correlation table indicating this characteristic, that is, a correlation in 39 or the like, it is possible to calculate the height position of the base material based on the signal output Op from the second light receiving unit 11bb. .
[0061]
Then, using the height position of the base material 100 as a drawing position, for example, the focal position of the electron beam is adjusted and drawing is performed.
[0062]
(Overview of the principle of drawing position calculation)
Next, the principle of drawing position calculation in the electron beam drawing device 1 will be described.
[0063]
As shown in FIGS. 12A and 12B, the base material 100 includes a flat portion 100b, and a curved surface portion 100a that is formed as a curved surface protruding from the flat portion 100b. The curved surface of the curved surface portion 100a is not limited to a spherical surface, and may be a free-form surface having a change in any other height direction, such as an aspheric surface.
[0064]
As described above, before the substrate 100 is placed on the XYZ stage 9, the position of the second mark 111b, for example, three reference points P00, P01, and P02 is measured by the shape measuring device 200. Keep it. Thereby, for example, the X axis is defined by the reference points P00 and P01, and the Y axis is defined by the reference points P00 and P02, and the first reference coordinate system in the three-dimensional coordinate system is calculated. Here, the height position in the first reference coordinate system is set to Ho (x, y) (first height position). Thereby, it is possible to calculate the height position distribution of the base material 2 and the error distribution from the design value.
[0065]
On the other hand, the same measurement is performed after the substrate 100 is placed on the XYZ stage 9. That is, as shown in FIG. 12A, the second mark 111b on the base material 100, for example, three reference points P10, P11, P12 are determined, and this position is measured using the measuring device 11. Keep it. Thus, for example, the X axis is defined by the reference points P10 and P11, and the Y axis is defined by the reference points P10 and P12, and the second reference coordinate system in the three-dimensional coordinate system is calculated.
[0066]
Further, a coordinate transformation matrix for transforming the first reference coordinate system into the second reference coordinate system is calculated from the reference points P00, P01, P02 and P10, P11, P12, and this coordinate transformation matrix is calculated. The height position Hp (x, y) (second height position) corresponding to the Ho (x, y) in the second reference coordinate system is calculated using this position, and this position is calculated as the optimum focus position, That is, the focus position of the electron beam is controlled as the drawing position.
[0067]
More specifically, as shown in FIG. 12C, the focal position of the focal depth FZ of the electron beam (beam waist BW = the narrowest point of the beam diameter) is set to one field (unit field) of the unit space in the three-dimensional reference coordinate system. The drawing position within m = 1) is adjusted and controlled.
[0068]
Then, as shown in FIG. 12 (C), for example, by sequentially scanning in one field while shifting in the Y direction in the X direction, drawing in one field is performed. Further, if there is an area in which no image is drawn in one field, the area is moved in the Z direction while controlling the above-described focal position, and the same scanning process is performed.
[0069]
Next, after the drawing in one field is performed, in the other fields, for example, the field of m = 2 and the field of m = 3, the drawing processing is performed in real time while measuring and calculating the drawing position as described above. Will be performed. In this manner, when all the drawing is completed for the drawing area to be drawn, the drawing process on the surface of the base material 2 ends.
[0070]
It should be noted that a processing program for performing the above-described various arithmetic processing, measurement processing, control processing, and the like is stored in the program memory 40 as a control program in advance.
[0071]
(Control system)
Next, the configuration of a control system in the electron beam writing apparatus 1 will be described with reference to FIG.
[0072]
As shown in FIG. 13, a shape storage table 39a is stored in the memory 39. The shape storage table 39a stores the shapes constituting the drawing pattern, for example, each scanning position of the electron beam when drawing a blaze. Dose distribution information 39aa in which the dose distribution corresponding to the laser beam is defined in advance, beam diameter information 39ab in which the beam diameter corresponding to each scanning position of the blaze is defined in advance, and measurement from the above-described shape measuring device and film thickness measuring device. The information, specifically, the shape data of the mother optical surface 110a of the matrix material 110 constituting the base material 100, the film thickness distribution data of the resist applied to the mother optical surface 110a, and further, each error distribution Data (error distribution data from the design value of the height position of the base optical surface 110a, error from the specified value of the film thickness of the resist applied to the base optical surface 110a) And correction calculation information 39ac comprising data), it contains other information 39 b.
[0073]
Further, the program memory 40 includes a processing program 40a for the control unit 41 to perform a process described below, and an interval between adjacent diffraction gratings that form a drawing pattern based on the correction calculation information 39ac. A correction calculation program 40b for adjusting the interval between adjacent blaze zones and a processing program 40c for other processes are stored.
[0074]
In such a configuration, the control unit 41, based on the dose distribution information 39aa stored in the shape storage table 39a of the memory 39 and the beam diameter information 39ab according to the processing program 40a, forms a shape that forms a drawing pattern, for example, A dose corresponding to each scanning position of the blaze 300 shown in FIG. 14A is calculated, and a probe current, a scanning pitch, and a diameter of the electron beam B are calculated.
[0075]
In addition, the pattern generation circuit 30 determines, based on the correction calculation information 39ac stored in the shape storage table 39a of the memory 39, the interval between adjacent diffraction gratings forming a drawing pattern, according to the correction calculation program 40b, as described later. For example, by adjusting the adjacent interval of the blaze ring 300a (the ring formed by the blaze 300) shown in FIG. 14B, shape data of a diffraction structure as a drawing pattern is created. The pattern generation circuit 30 corresponds to the “drawing adjustment unit” of the present invention.
[0076]
Further, the control unit 170 controls the electron gun control unit 22, the electric field control circuit 29, the lens control unit 24, and the like based on the calculated probe current, scanning pitch, and diameter of the electron beam B. As a result, the probe current, the scanning pitch, and the diameter of the electron beam B at the time of drawing are optimized, and a diffraction structure as a predetermined drawing pattern is drawn. The control unit 170 corresponds to the “control unit” of the present invention.
[0077]
(Details of the drawing adjustment process)
Here, the details of the adjustment processing of the drawing pattern by the above-described pattern generation circuit 30 will be described.
[0078]
First, the pattern generation circuit 30 applies the correction operation information 39ac stored in the shape storage table 39a of the memory 39, that is, the error distribution data from the design value of the height position of the base optical surface 110a, and the application to the base optical surface 110a. Based on the obtained error distribution data from the specified value of the resist film thickness, error distribution data from the specified value of the height of the surface to be drawn, that is, the surface of the curved surface portion 100a is created.
[0079]
Next, based on the error distribution data from the prescribed value of the height position of the surface of the curved surface portion 100a, that is, the error dt from the prescribed value of the height position of the surface of the curved surface portion 100a, according to the correction calculation program 40b, By performing the arithmetic processing described, the correction amount δp of the interval of the diffraction grating drawn on the surface of the curved surface portion 100a is calculated.
[0080]
Here, the relationship between the shift amount δp of the interval of the diffraction grating drawn on the surface of the curved surface portion 100a and the phase change X of the diffracted light is expressed by (Equation 1).

(However, δp << p)
It becomes.
Further, the relationship between the error dt from the prescribed value of the height position of the surface of the curved surface portion 100a and the phase change of the diffracted light is expressed by (Equation 2).
X = − (n−1) dt / dr (Equation 2)
It becomes.
Here, m: the order of the diffracted light, λ: the wavelength of the light, p: the specified value of the interval between the diffraction gratings, n: the refractive index, and r: the distance from the center of the substrate 100.
[0081]
When you create a relational expression from these expressions,
dt / dr = mλ / − (n−1) δp / p ² ... (Equation 3)
It becomes.
[0082]
Further, when the deviation amount δp of the interval between the diffraction gratings is derived from (Equation 3),
δp = − (n−1) p ² / Mλ × dt / dr (Equation 4)
It becomes.
[0083]
That is, the pattern generating circuit 30 calculates the error dt from the specified value of the height position of the surface of the curved surface portion 100a in accordance with the correction calculation program 40b, substitutes the calculated error dt into (Equation 3), and uses (Equation 4) , The correction amount δp of the interval between the diffraction gratings is calculated.
[0084]
Therefore, as shown in FIG. 15A, for example, at a position r in the radial direction on an arbitrary line rn (n = 1, 2, 3,...) Of the base material 100, a prescribed value is set as the height position of the surface of the curved surface portion 100a. If an error dt from the above occurs, the shape of the curved surface portion 100a can be adjusted by increasing or decreasing the interval between the diffraction zones 300a at that position by δp calculated from (Equation 4) from the specified value. The phase change of the diffracted light caused by the error can be corrected.
[0085]
At this time, as shown in FIG. 15B, for example, if the height position of the curved surface portion 100a tends to be larger than a specified value at a radial position r on an arbitrary line rn of the base material 100, The interval between the diffraction zones in that portion is adjusted to be smaller than a specified value. Conversely, if the distance tends to be smaller, the interval between the diffraction zones in that portion is adjusted to be wider than the specified value.
[0086]
By drawing the diffractive structure adjusted in this manner, the processing error in the above-described cutting process (error from the design value of the height position of the base optical surface 110a) and the processing error in the resist film forming process (base error) An error from the prescribed value of the film thickness of the resist applied to the optical surface 110a) can be resolved, and a diffraction structure that can obtain predetermined optical performance can be drawn.
[0087]
Returning to FIG. 2, after drawing by the electron beam drawing apparatus 1, the member E is removed from the three-dimensional stage 9 (step S31).
[0088]
[Manufacturing method of mother die Part 3]
Next, a method of manufacturing the mother die (third part) will be described with reference to FIG. 3 along the flow of the flowchart shown in FIG.
[0089]
<Development process>
As shown in FIG. 2, the member E is further subjected to a developing process by a developing device (not shown) to obtain an annular resist (step S32). It should be noted that the longer the irradiation time of the electron beam at the same point is, the more the removal amount of the resist increases. Therefore, in the above-described drawing process, the irradiation position and the irradiation time (dose amount) of the electron beam are adjusted. The resist can be left so as to form a blaze ring.
[0090]
<Etching process>
Further, the member E is etched by an etching device (not shown) to engrave the surface of the mother optical surface 110a of the master mold material 110 to form a blazed annular zone 110b (illustrated exaggeratedly in reality). Is formed (see FIG. 3E) (step S33).
[0091]
Through the steps so far, the member E is completed as a matrix.
[0092]
[Mold manufacturing method]
Next, a method for manufacturing the mold will be described with reference to FIG. 3 along the flow of the flowchart shown in FIG.
[0093]
<Electroforming process>
As shown in FIG. 2, the matrix, the surface of which has been subjected to the activation treatment, that is, the member E is further immersed in a nickel sulfamate bath, and an electric current is caused to flow between the base material 111 and the external electrode 114, whereby the electric current is applied. The cast 120 is grown (see FIG. 3F) (step S34). At this time, by applying an insulating agent to the outer peripheral surface 111f of the base material 111, it is possible to suppress the electroforming of the portion where the insulating agent is applied. In the course of its growth, the electroforming 120 forms an optical surface transfer surface 120a accurately corresponding to the mother optical surface 110a and an annular transfer surface 120b accurately corresponding to the annular zone 110b.
[0094]
Thereafter, a database built in a computer (not shown) is searched based on the ID number NX of the yat 150 corresponding to the member E being processed, and the obtained yatoy 150 (that is, used in the cutting process) is obtained. Is attached to the member E (base material 111) under predetermined attachment conditions (step S35). The predetermined attachment condition is the attachment condition in the first step, and more specifically, matching the matching mark MX to match the phase of the base material 111 and the toy 150, and the read-out work environment temperature during tightening ( A working environment temperature of ± 1.0 degrees with respect to the working environment temperature in the first step, tightening with the read tightening torque (tightening torque in the cutting step), and using the same bolt 152 Mounting.
[0095]
Further, after the working environment temperature at the time of cutting of the member E being processed is stored in a database constructed in a computer (not shown), the member E and the electroformed And the toy 150 are integrally attached to the chuck so that the rotation axis of the SPDT processing machine and the optical axis of the member E coincide with each other, and the outer peripheral surface 120c of the electroforming 120 is cut (see FIG. 3 (g)). (Step S36).
[0096]
In addition, as shown in FIG. 3 (g), a pin hole 120d (center) and a screw hole 120e as a positioning portion for a backing member are formed in the electroformed 120. Note that a cylindrical shaft may be formed instead of the pin hole 120d. After the processing, the member E, the electroforming 120 and the toy 150 are integrally removed from the SPDT processing machine.
[0097]
Further, the movable core 130 is formed by integrating the electroforming 120 with the backing member as described below (Step S37).
[0098]
FIG. 16 is a cross-sectional view of the movable core 130 in a state where the member E is attached. In FIG. 16, the movable core 130 includes an electroformed member 120 disposed at a front end (right side in the figure), a pressing portion 136 disposed at a rear end (left side in the figure), and a sliding member 135 disposed therebetween. Is done. The sliding member 135 and the pressing portion 136 serve as a backing member.
[0099]
The electroforming 120 is positioned in a predetermined relationship with the sliding member 135 by engaging a pin 135a protruding from the center of the end surface of the cylindrical sliding member 135 into the pin hole 120d, and The bolt 137 inserted into the two bolt holes 135b penetrating the member 135 in parallel with the axis is screwed into the screw hole 120e, so that the electroforming 120 is attached to the sliding member 135.
[0100]
The sliding member 135 is provided with a screw shaft 135c formed at the center of an end surface (the left end in the figure) facing the end surface (the right end in the figure) provided with the pin portion 135a, and the end of the substantially cylindrical pressing portion 136. By being screwed into a screw hole 136a formed in the portion, it is attached to the pressing portion 136 in a predetermined positional relationship. In FIG. 16, the outer peripheral surface 135 e of the sliding member 135 has a larger diameter than the outer peripheral surfaces of the portions other than the electroformed portion 120 and the flange portion 136 b of the pressing portion 136. After attaching the sliding member 135 and the pressing portion 136 as the backing member, the jaws 150 are attached to the chuck of the SPDT processing machine (step S38).
[0101]
Further, after setting the working environment temperature at the time of cutting of the member E being processed from a database constructed in a computer (not shown), the sliding member 135 and the pressing portion 136 are determined with reference to the outer peripheral surface 111f of the base material 111. Finish the outer peripheral surface (step S39). For this reason, even though the jaws 150 are once removed from the base material 111, the coaxiality between the center of the concentric pattern (ring zone 110b) of the mother die 110 and the center of the outer shape of the mold sliding portion can be kept within 1 μm. it can. Further, the end face of the pressing portion 136 is cut so that the entire length falls within a specified value (step S40).
[0102]
After that, the member E and the toy 150 are removed from the electroforming 120 attached to the sliding member 135 and the pressing portion 136 by cutting at a position indicated by an arrow X in FIG. 16 (step S41). Further, after the electroforming 120 and the substrate 210 are removed from the mold, the electroforming 120 at the tip of the movable core 130 is finished to obtain a mold for molding an optical element (step S42).
[0103]
By the steps so far. An optical element molding die is manufactured.
[0104]
[Manufacture of optical element]
FIG. 17 is a diagram illustrating a state in which an optical element is molded using the movable core 130 formed as described above. In FIG. 17, a holding portion 142 that holds an optical element molding die 141 having an optical surface transfer surface 141 a is fixed to a movable side cavity 143. The movable cavity 143 has a small opening 143a and a large opening 143b coaxial with the small opening. When the movable core 130 is inserted into the movable side cavity 143, the outer peripheral surface 135e of the sliding member 135 slides on the inner peripheral surface of the small opening 143a, and the outer peripheral surface 136d of the flange portion 136b of the pressing portion 136 is It slides on the inner peripheral surface of the large opening 143b. By being guided by the two sliding portions, the movable core 130 can move in the axial direction without largely tilting with respect to the movable side cavity 143.
[0105]
The molten resin is injected between the optical element molding die 141 and the electroforming 120, and the movable core 130 is pressed in the direction of the arrow, whereby the optical element OE is molded. According to the present embodiment, by using electroforming 120 as an optical element molding die accurately transferred and formed from base material 110, the optical surface of electroforming The surface transfer surface 120a is transferred and formed, and the diffraction ring corresponding to the ring transfer surface 120b is formed with high accuracy concentrically on the optical axis.
[0106]
By the steps so far. An optical element is manufactured.
[0107]
When the optical element molding die is processed as described above, a projection (not shown) corresponding to the second mark 111b is transferred and formed on the electroforming 120, and this is used as a processing reference. By using this, it is possible to perform highly accurate processing of the outer peripheral surface and the like.
[0108]
As described above, according to the electron beam writing method in the present embodiment, a predetermined optical performance can be obtained by performing correction for eliminating processing errors accumulated in the cutting step or the resist film forming step. Diffraction structures can be drawn.
[0109]
Although the method of drawing a substrate and the electron beam drawing apparatus according to the present invention have been described in accordance with the specific embodiments, those skilled in the art will appreciate that the present invention can be carried out without departing from the spirit and scope of the present invention. Various modifications can be made to the embodiment described in.
[0110]
For example, the measurement information from the shape measuring device 200 and the film thickness measuring device is input from the measurement information input unit 158 of the electron beam writing apparatus 1 and data is transferred via a network (not shown) connected to the control circuit 20. Then, it may be stored in the memory 39 or the like.
[0111]
In addition, the shape measurement of the member E, that is, the measurement of the three-dimensional coordinates of the mother optical surface 110a of the master mold material 110 is performed not by the shape measuring device 200 but by the measuring device 11 of the electron beam writing apparatus 1. Is also good.
[0112]
Further, immediately after the shape measurement of the member E, the electron beam drawing apparatus 1 may be used to perform drawing to correct an error in the height position of the base optical surface 110a of the base mold material 110.
[0113]
In addition, after measuring the shape of the member E and applying a resist to the member E, only measuring the thickness of the resist film is performed to correct an error in the height position of the mother optical surface 110a of the master mold material 110. You may decide.
[0114]
【The invention's effect】
As described above, according to the electron beam writing method according to the present invention, it is possible to perform a correction for eliminating a processing error accumulated in another process, and to write a diffraction structure that can obtain a predetermined optical performance. .
[Brief description of the drawings]
FIG. 1 is a flowchart showing steps constituting a method for manufacturing a matrix, an electron beam drawing method, and a method for manufacturing a mold in the present embodiment.
FIG. 2 is a flowchart showing steps constituting a method for manufacturing a matrix, an electron beam drawing method, and a method for manufacturing a mold in the present embodiment.
FIG. 3 is a cross-sectional view showing an assembly of a matrix material and an electrode member, that is, a member E, which is processed in the main steps shown in FIGS. 1 and 2;
FIG. 4 is a perspective view of a member E to which a yatoy is attached.
FIG. 5 is a top view of the member E shown in FIG.
FIG. 6 is an explanatory view showing the entire configuration of a shape measuring instrument.
FIG. 7 is an explanatory diagram showing an overall configuration of an electron beam writing apparatus.
FIG. 8 is an explanatory diagram for explaining a beam waist of an electron beam.
FIG. 9 is an explanatory diagram for explaining the overall configuration of the measuring device.
FIG. 10 is an explanatory diagram for explaining the measurement principle of the measurement device.
FIG. 11 is a characteristic diagram showing a relationship between a signal output and a height of a base material.
FIGS. 12A and 12B are explanatory views showing a base material drawn by an electron beam drawing apparatus, and FIG. 12C is a view for explaining a drawing principle of the electron beam drawing apparatus; FIG.
FIG. 13 is an explanatory diagram showing a configuration of a control system of the electron beam writing apparatus.
FIG. 14 is an explanatory diagram for explaining a process of adjusting adjacent intervals of diffraction zones constituting a diffraction structure drawn on a base material.
FIG. 15 is an explanatory diagram for explaining a relationship between a shape error of a curved surface portion (a drawing surface) of a base material and a correction amount of an adjacent interval between diffraction zones.
FIG. 16 is a sectional view of a movable core.
FIG. 17 is a diagram illustrating a state in which an optical element is molded using a movable core.
[Explanation of symbols]
100 base material
100a Curved surface
100b flat part
300a diffraction zone
p Specified value of the interval between diffraction zones
δp Correction value of the interval between diffraction zones
dt Error in height of curved surface
r Position in radial direction

Claims (17)

An electron beam drawing method for drawing a predetermined diffraction structure on the base material by scanning the base material with an electron beam,
A shape measurement step of measuring an error from a specified value of the height distribution of the surface of the base material,
In accordance with an error from a prescribed value of the height distribution, an interval between the individual diffraction gratings is adjusted so as to correct a phase change due to the error of the diffracted light corresponding to the individual diffraction gratings constituting the diffraction structure. A drawing adjustment process to
A drawing step of drawing the individual diffraction gratings by scanning an electron beam in accordance with the adjusted intervals. A film thickness measuring step of measuring an error from a specified value of the film thickness distribution of the resist film formed on the base material, further comprising:
In the drawing adjustment step, an error from a specified value of the height distribution and an error from a specified value of the film thickness distribution, the diffracted light corresponding to each diffraction grating constituting the diffractive structure, 2. The electron beam writing method according to claim 1, wherein an interval between the individual diffraction gratings is adjusted so as to correct a phase change due to an error. An electron beam drawing method for drawing a predetermined diffraction structure on the base material by scanning the base material with an electron beam,
A film thickness measuring step of measuring an error from a specified value of the film thickness distribution of the resist film formed on the base material,
In accordance with an error from a prescribed value of the film thickness distribution, an interval between the individual diffraction gratings is adjusted so as to correct a phase change due to the error of the diffracted light corresponding to the individual diffraction gratings constituting the diffraction structure. A drawing adjustment process to
A drawing step of drawing the individual diffraction gratings by scanning an electron beam in accordance with the adjusted intervals. In the drawing adjustment step, when the sign of the error is positive, the interval between the individual diffraction gratings is adjusted to be small, and when the sign of the error is negative, the interval between the individual diffraction gratings is adjusted. The electron beam writing method according to claim 1, wherein the adjustment is performed largely. The electron beam drawing method according to claim 1, wherein a drawing surface of the base material has a curved shape. A method of manufacturing a mold for manufacturing a mold for forming an optical element by using a substrate drawn by the electron beam drawing method according to claim 1. So,
A method for manufacturing a matrix, comprising a cutting step of obtaining the base material by cutting a material. The method according to claim 6, further comprising a resist film forming step of forming a resist film on the substrate obtained in the cutting step. 8. The mold according to claim 6, further comprising a developing step of developing a resist film on the base material drawn in the drawing step to obtain a master having a predetermined diffraction structure. Manufacturing method. The method according to claim 8, further comprising an etching step of etching the base material developed in the developing step. A mother die manufactured by the method for manufacturing a mother die according to any one of claims 6 to 9. A method for manufacturing a mold, comprising: performing an electroforming process using the matrix of claim 10 to obtain a mold on which the predetermined structure on the matrix has been transferred. A mold manufactured by the method for manufacturing a mold according to claim 11. An optical element formed by the mold according to claim 12. By scanning an electron beam on the substrate, an electron beam writing apparatus that draws a predetermined diffraction structure on the substrate,
An electron beam irradiation means for irradiating the base material with an electron beam,
Electron beam scanning means for scanning by deflecting the electron beam emitted from the electron beam irradiation means,
Shape information acquisition means for acquiring an error from a prescribed value of the height distribution of the surface of the base material,
In accordance with an error from a prescribed value of the height distribution, an interval between the individual diffraction gratings is adjusted so as to correct a phase change due to the error of the diffracted light corresponding to the individual diffraction gratings constituting the diffraction structure. Drawing adjustment means to
An electron beam writing apparatus, comprising: a control unit that controls the electron beam scanning unit to scan an electron beam in accordance with the adjusted interval to write the individual diffraction gratings. A film thickness information acquisition unit for acquiring an error from a specified value of the film thickness distribution of the resist film formed on the base material, further including:
The drawing adjustment unit is configured to determine the error of the diffracted light corresponding to each diffraction grating constituting the diffraction structure according to an error from a specified value of the height distribution and an error from a specified value of the film thickness distribution. The electron beam writing apparatus according to claim 14, wherein an interval at which the individual diffraction gratings are written is adjusted so as to correct a phase change due to an error. By scanning an electron beam on the substrate, an electron beam writing apparatus that draws a predetermined diffraction structure on the substrate,
An electron beam irradiation means for irradiating the base material with an electron beam,
Electron beam scanning means for scanning by deflecting the electron beam emitted from the electron beam irradiation means,
Film thickness information acquisition means for acquiring an error from a specified value of the film thickness distribution of the resist film formed on the base material,
In accordance with an error from a prescribed value of the film thickness distribution, an interval between the individual diffraction gratings is adjusted so as to correct a phase change due to the error of the diffracted light corresponding to the individual diffraction gratings constituting the diffraction structure. Drawing adjustment means to
An electron beam writing apparatus, comprising: a control unit that controls the electron beam scanning unit to scan an electron beam in accordance with the adjusted interval to write the individual diffraction gratings. The drawing adjustment means adjusts the interval between the individual diffraction gratings to be small when the sign of the error is positive, and adjusts the interval between the individual diffraction gratings when the sign of the error is negative. The electron beam lithography apparatus according to claim 14, wherein the electron beam lithography apparatus is adjusted to be large.

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