JPH0797170B2 - Optical element manufacturing method - Google Patents
Optical element manufacturing methodInfo
- Publication number
- JPH0797170B2 JPH0797170B2 JP61306957A JP30695786A JPH0797170B2 JP H0797170 B2 JPH0797170 B2 JP H0797170B2 JP 61306957 A JP61306957 A JP 61306957A JP 30695786 A JP30695786 A JP 30695786A JP H0797170 B2 JPH0797170 B2 JP H0797170B2
- Authority
- JP
- Japan
- Prior art keywords
- optical element
- substrate
- proton exchange
- etching
- manufacturing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Optical Integrated Circuits (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明はコヒーレント光を利用する光情報処理分野、あ
るいは光応用計測制御分野に使用する光導波路およびマ
イクロレンズの製造に用いる光素子の製造方法に関する
ものである。Description: TECHNICAL FIELD The present invention relates to a method for manufacturing an optical element used for manufacturing an optical waveguide and a microlens used in the field of optical information processing using coherent light or in the field of optical measurement and control. Is.
従来の技術 従来、強誘電体基板であるLiNbO3基板にCrまたはAlなど
を蒸着し、フォトプロセスおよびエッチングにより幅数
μｍのスリットを開けたものを安息香酸中で熱処理を行
い高屈折率層（基板との屈折率差Δne＝0.13程度）を形
成していた〔J.L.Jackel,C.E.Rice,and J.J.Veselka,
“Proton exchange for highindey waueguides in LiNb
O3"アプライド フィジックス レター（Appl.Phys.Let
t.）,Vol41,No.7,PP607−608（1982））参照〕。Conventional technology Conventionally, a LiNbO 3 substrate, which is a ferroelectric substrate, is vapor-deposited with Cr or Al, and a slit having a width of several μm is formed by photoprocess and etching, and heat treatment is performed in benzoic acid to obtain a high refractive index layer ( The refractive index difference Δn e with the substrate was about 0.13) [JLJackel, CE Rice, and JJ Veselka,
“Proton exchange for highindey waueguides in LiNb
O 3 "Applied Physics Letter (Appl.Phys.Let
t.), Vol 41, No. 7, PP 607-608 (1982))].
以下光素子として光導波路を例にとりその作製方法につ
いて説明する。第３図に従来の溶液中でのプロトン交換
方法を用いた埋め込み型光導波路の製造方法の具体的構
成図を示す。保護マスク３およびスリット３′が形成さ
れたLiNbO3基板１を安息香酸４、230℃中で12分程度熱
処理を行うことでスリット３′直下に高屈折率層２が形
成され、このストライプ状の高屈折率層２が厚み0.5μ
ｍ程度の埋込み型光導波路となる。An optical waveguide will be taken as an example of the optical element to describe a method of manufacturing the optical element. FIG. 3 shows a specific configuration diagram of a conventional method for manufacturing an embedded optical waveguide using a proton exchange method in a solution. The LiNbO 3 substrate 1 on which the protective mask 3 and the slits 3'are formed is heat-treated in benzoic acid 4 at 230 ° C for about 12 minutes to form a high refractive index layer 2 directly below the slits 3 ', and the stripe-shaped layer 2 is formed. High refractive index layer 2 has a thickness of 0.5μ
It becomes a buried type optical waveguide of about m.
上記埋込み型光導波路は横方向の閉じ込めが悪くリッジ
型にすることが望まれる。第４図に従来のリッジ型光導
波路の製造工程図を示す。第４図ａでLiNbO3基板１上に
Tiによる保護マスクパターン３を形成し、同図ｂで反応
性イオンビームエッチングによりエッチングを行う。最
後に同図ｃでプロトン交換を行い高屈折率層２が形成さ
れる。高屈折率層２のリッジ部２′に光導波路が作製さ
れる。The embedded optical waveguide has a poor lateral confinement and is desired to be a ridge type. FIG. 4 shows a manufacturing process diagram of a conventional ridge type optical waveguide. On the LiNbO 3 substrate 1 in FIG.
A protective mask pattern 3 made of Ti is formed, and etching is performed by reactive ion beam etching in FIG. Finally, the high refractive index layer 2 is formed by performing proton exchange in FIG. An optical waveguide is formed in the ridge portion 2'of the high refractive index layer 2.
発明が解決しようとする問題点 上記のような光素子の製造方法ではLiNbO3基板１のエッ
チングレートが遅くマスクに対する選択比を大きくでき
ないため保護マスクの厚みを増す必要があり、１μｍ〜
２μｍの線幅での微細加工が困難であることおよび選択
比が悪く側面が垂直にならない（制御性が悪い）といっ
た問題点があった。Problems to be Solved by the Invention In the above-described method for manufacturing an optical element, the etching rate of the LiNbO 3 substrate 1 is slow and the selectivity to the mask cannot be increased. Therefore, it is necessary to increase the thickness of the protective mask.
There are problems that it is difficult to perform fine processing with a line width of 2 μm, the selection ratio is poor, and the side surfaces are not vertical (poor controllability).
問題点を解決するための手段 本発明は上記問題点を解消するもので、光素子の製造方
法に新たな工夫を加えることにより制御性，量産性を大
幅に向上させるものである。すなわち、本発明の光素子
の製造方法はLiNbxTa(1-x)O3（０≦Ｘ≦１）基板を燐酸
を主成分とする酸中で熱処理を行い、前記基板にプロト
ン交換層を形成する工程と、前記プロトン交換層をエッ
チングする工程とを有するという手段を用いるものであ
る。Means for Solving the Problems The present invention solves the above problems, and greatly improves the controllability and mass productivity by adding a new device to the method of manufacturing an optical element. That is, in the method for manufacturing an optical element of the present invention, a LiNb x Ta (1-x) O 3 (0 ≦ X ≦ 1) substrate is heat-treated in an acid containing phosphoric acid as a main component, and a proton exchange layer is formed on the substrate. The method has a step of forming and a step of etching the proton exchange layer.
作用 本発明は上記手段によりLiNbxTa1-xO3（０≦ｘ≦１）基
板にプロトン交換処理を施し増殖エッチングを行い、保
護マスクとの選択比およびエッチング時間の大幅な短縮
が図れる。Action According to the present invention, the LiNb x Ta 1-x O 3 (0 ≦ x ≦ 1) substrate is subjected to the proton exchange treatment by the above-mentioned means to perform the multiplication etching, and the selection ratio to the protective mask and the etching time can be greatly shortened.
実施例 本発明の光素子の製造方法の第１の実施例の工程図を第
１図に示す。この実施例では光素子の製造方法としてLi
NbO3基板１にリッジ型光導波路を作製する場合について
説明する。第１図ａで１は＋Ｚ板（Ｚ軸と垂直に切り出
された基板の＋側）のLiNbO3基板〔LiNbxTa(1-x);0≦Ｘ
≦１〕、２は燐酸中でのプロトン交換処理により形成さ
れた厚み0.5μｍの高屈折率層である。次に同図ｂで上
記高屈折率層２上に通常のフォトプロセスおよび蒸着に
よりTiをパターン化し保護マスク３とした。最後に同図
ｃでCF4によるドライエッチングにより100W,3×10-2Tor
r,10分間エッチングを行った。Example FIG. 1 shows a process chart of a first example of a method for manufacturing an optical element of the present invention. In this embodiment, as a method of manufacturing an optical element, Li
A case of forming a ridge type optical waveguide on the NbO 3 substrate 1 will be described. In FIG. 1a, 1 is a + Z plate (+ side of the substrate cut out perpendicular to the Z axis) of a LiNbO 3 substrate [LiNb x Ta (1-x) ; 0 ≦ X
≦ 1], 2 is a high-refractive index layer having a thickness of 0.5 μm formed by a proton exchange treatment in phosphoric acid. Next, as shown in FIG. 3B, Ti was patterned on the high refractive index layer 2 by a normal photo process and vapor deposition to form a protective mask 3. Finally, in Figure c, dry etching with CF 4 was performed with 100 W, 3 × 10 -2 Tor.
Etching was performed for 10 minutes.
上記のような工程によりリッジ型光導波路が製造され
た。この光導波路は横方向にも閉じ込められているため
曲がりなどにも強い。またエッチング時の選択比はLiNb
O3基板１に対するTiが３であったのに対して６倍の選択
比20を得た。またエッジの角度は制御性良く垂直となっ
ている。第２図にCF4ガス100W,3.5×10-2Torrでのエッ
チングレートを示す。A ridge-type optical waveguide was manufactured by the above-mentioned process. Since this optical waveguide is also confined in the lateral direction, it is strong against bending. Also, the selection ratio during etching is LiNb.
While the Ti was 3 for the O 3 substrate 1, a selection ratio 20 of 6 times was obtained. The edge angle is vertical with good controllability. Figure 2 shows the etching rate at 100 W of CF 4 gas and 3.5 × 10 -2 Torr.
なおフッ素系のガスとしてCF4を用いたがCHF3,C3F8など
でも良い。またプロトン交換用の酸として燐酸を用いた
が燐酸系の酸（ピロ燐酸）などが簡単に制御性良く光導
波路を形成できるので良い。Although CF 4 is used as the fluorine-based gas, CHF 3 , C 3 F 8 or the like may be used. Phosphoric acid was used as the proton exchange acid, but phosphoric acid (pyrophosphoric acid) or the like is preferable because it can easily form an optical waveguide with good controllability.
また実施例ではフッ素系のガスを用いたが、フッ酸など
のフッ素系酸の溶液中でのウェットエッチングを用いる
とさらに選択比を向上させることが可能である。Further, although a fluorine-based gas is used in the examples, it is possible to further improve the selection ratio by using wet etching in a solution of a fluorine-based acid such as hydrofluoric acid.
発明の効果 本発明の光素子の製造方法によれば、LiNbxTa1-xO3（０
≦ｘ≦１）基板に燐酸を主成分とする酸中でプロトン交
換処理を行うことで大幅にエッチングレートを向上させ
保護マスクとの選択比を増し制御性，量産性の向上が図
れる。EFFECTS OF THE INVENTION According to the method of manufacturing an optical element of the present invention, LiNb x Ta 1-x O 3 (0
≦ x ≦ 1) By performing a proton exchange treatment on the substrate in an acid containing phosphoric acid as a main component, the etching rate is greatly improved, the selection ratio with the protective mask is increased, and controllability and mass productivity are improved.
第１図ａ〜ｃは本発明の光素子の形成方法の実施例の工
程図、第２図はLiNbO3およびプロトン交換層のエッチン
グ量の時間依存性のグラフ、第３図ａは従来の光素子の
形成方法を説明するための図、第３図ｂは同方法を適用
する基板の斜視図、第４図ａ〜ｃは同従来の方法の工程
図である。 １……LiNbO3基板、２……高屈折率層、３……保護マス
ク。1 (a) to 1 (c) are process diagrams of an embodiment of a method for forming an optical element of the present invention, FIG. 2 is a graph of time dependence of etching amounts of LiNbO 3 and a proton exchange layer, and FIG. 3 is a perspective view of a substrate to which the method is applied, and FIGS. 4A to 4C are process diagrams of the conventional method. 1 …… LiNbO 3 substrate, 2 …… High refractive index layer, 3 …… Protective mask.
Claims (3)
主成分とする酸中で熱処理を行い、前記基板にプロトン
交換層を形成する工程と、 前記プロトン交換層をエッチングする工程と、を有する
ことを特徴とする光素子の製造方法。1. A step of heat-treating a LiNb x Ta 1-x O 3 (0 ≦ x ≦ 1) substrate in an acid containing phosphoric acid as a main component to form a proton exchange layer on the substrate, and the proton exchange. And a step of etching the layer.
いてプロトン交換層のエッチングを行うことを特徴とす
る特許請求の範囲第１項記載の光素子の製造方法。2. The method of manufacturing an optical element according to claim 1, wherein the proton exchange layer is etched by using dry etching in a fluorine-based gas.
用いてプロトン交換層のエッチングを行うことを特徴と
する特許請求の範囲第１項記載の光素子の製造方法。3. The method of manufacturing an optical element according to claim 1, wherein the proton exchange layer is etched by using wet etching in a fluorine-based solution.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61306957A JPH0797170B2 (en) | 1986-12-23 | 1986-12-23 | Optical element manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61306957A JPH0797170B2 (en) | 1986-12-23 | 1986-12-23 | Optical element manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63158506A JPS63158506A (en) | 1988-07-01 |
| JPH0797170B2 true JPH0797170B2 (en) | 1995-10-18 |
Family
ID=17963306
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61306957A Expired - Fee Related JPH0797170B2 (en) | 1986-12-23 | 1986-12-23 | Optical element manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0797170B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH103100A (en) * | 1996-04-15 | 1998-01-06 | Matsushita Electric Ind Co Ltd | Optical waveguide parts, optical parts, manufacture of optical waveguide parts, and manufacture of periodic polarization inversion structure |
| JP3863277B2 (en) * | 1998-02-17 | 2006-12-27 | 日本碍子株式会社 | Processing method of ferroelectric crystal substrate |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58154820A (en) * | 1982-02-10 | 1983-09-14 | Fujitsu Ltd | Formation of waveguide for optical switch |
| JPS607403A (en) * | 1983-06-28 | 1985-01-16 | Canon Inc | Forming method of thin film type optical waveguide |
-
1986
- 1986-12-23 JP JP61306957A patent/JPH0797170B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63158506A (en) | 1988-07-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |