JPH0323884B2 - - Google Patents
Info
- Publication number
- JPH0323884B2 JPH0323884B2 JP15523685A JP15523685A JPH0323884B2 JP H0323884 B2 JPH0323884 B2 JP H0323884B2 JP 15523685 A JP15523685 A JP 15523685A JP 15523685 A JP15523685 A JP 15523685A JP H0323884 B2 JPH0323884 B2 JP H0323884B2
- Authority
- JP
- Japan
- Prior art keywords
- film
- diffraction grating
- region
- photoresist
- substrate
- 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
Links
- 229920002120 photoresistant polymer Polymers 0.000 claims description 47
- 238000004519 manufacturing process Methods 0.000 claims description 24
- 239000000758 substrate Substances 0.000 claims description 21
- 238000000034 method Methods 0.000 claims description 18
- 238000000926 separation method Methods 0.000 claims description 16
- 238000005530 etching Methods 0.000 claims description 4
- 239000003989 dielectric material Substances 0.000 claims 1
- 239000007769 metal material Substances 0.000 claims 1
- 239000011368 organic material Substances 0.000 claims 1
- 239000010408 film Substances 0.000 description 72
- 230000000737 periodic effect Effects 0.000 description 9
- 239000002184 metal Substances 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 239000012528 membrane Substances 0.000 description 6
- 238000010894 electron beam technology Methods 0.000 description 5
- 238000003486 chemical etching Methods 0.000 description 3
- NCGICGYLBXGBGN-UHFFFAOYSA-N 3-morpholin-4-yl-1-oxa-3-azonia-2-azanidacyclopent-3-en-5-imine;hydrochloride Chemical compound Cl.[N-]1OC(=N)C=[N+]1N1CCOCC1 NCGICGYLBXGBGN-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229920003986 novolac Polymers 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
Landscapes
- Diffracting Gratings Or Hologram Optical Elements (AREA)
Description
【発明の詳細な説明】
（発明の技術分野）
本発明は、２光束干渉露光を用いて周期的な凹
凸から成る回折格子を構造する方法に係わり、特
に、隣接する二つの領域において回折格子の凹凸
の位相が反転する構造を有する回折格子の製造方
法に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method of constructing a diffraction grating consisting of periodic irregularities using two-beam interference exposure. The present invention relates to a method for manufacturing a diffraction grating having a structure in which the phase of concave and convex portions is inverted.
（従来技術とその問題点）
周期的な凹凸から成る回折格子は、所望の波長
の光のみを反射あるいは通過させるため、光通信
の分野においてはフイルタとしてあるいは分布帰
還形半導体レーザ（以下、「DFBレーザ」と略
す）の内部等に用いられている。(Prior art and its problems) Diffraction gratings consisting of periodic concavities and convexities reflect or pass only light of a desired wavelength, so they are used as filters or distributed feedback semiconductor lasers (hereinafter referred to as "DFB") in the field of optical communication. It is used inside a laser (abbreviated as "laser").
その中で、発光領域またはその近傍に回折格子
を有するDFBレーザは、単一軸モードの光を発
することから、光通信の光源として脚光を浴び、
従来から種々の提案がある。特に最近では、回折
格子の中央部付近で凹凸の位相を反転した方がさ
らに安定な単一モード動作を行うものとして注目
されている。 Among these, DFB lasers, which have a diffraction grating in or near the light emitting region, have attracted attention as a light source for optical communications because they emit light in a single-axis mode.
There have been various proposals in the past. Particularly recently, inverting the phase of the unevenness near the center of the diffraction grating has attracted attention as a way to achieve more stable single mode operation.
このようなDFBレーザの発振波長は回折格子
の凹凸の周期Λで決定され、さらに安定な動作は
回折格子の製作精度に依存する。従つて、回折格
子の製作精度がDFBレーザの特性を左右するこ
とになる。 The oscillation wavelength of such a DFB laser is determined by the period Λ of the unevenness of the diffraction grating, and stable operation also depends on the manufacturing precision of the diffraction grating. Therefore, the manufacturing precision of the diffraction grating influences the characteristics of the DFB laser.
凹凸の位相が反転した構造を有する回折格子の
従来の製造方法を述べる前に、まず凹凸の位相が
反転しない構造の回折格子の製造方法について説
明する。 Before describing a conventional method for manufacturing a diffraction grating having a structure in which the phase of the concave and convex portions is inverted, a method for manufacturing a diffraction grating having a structure in which the phase of the concave and convex portions is not inverted will be described first.
第１図は従来の２光束干渉露光法による一様な
回折格子の製造の原理図である。波長λ0なる例え
ばHe−Cdレーザ光３をハーフミラー４で２つに
分波し、各々の分波光３はミラー５で反射させ、
その分波光３の合成波を図示のように基板１の上
に例えばポジタイプのフオトレジスト膜２を塗布
した結晶表面に照射したときに生じる干渉パター
ンにより露光し、現像とエツチングを行えば回折
格子を形成することができる。ここで、凹凸の周
期Λはレーザ光３の入射角をαとすれば、
Λ＝λ0／2sinα ……(1)
で求められる。 FIG. 1 is a diagram showing the principle of manufacturing a uniform diffraction grating by a conventional two-beam interference exposure method. For example, a He-Cd laser beam 3 with a wavelength λ 0 is split into two by a half mirror 4, and each split beam 3 is reflected by a mirror 5.
As shown in the figure, the synthesized wave of the split light 3 is irradiated onto the surface of a crystal coated with, for example, a positive type photoresist film 2 on the substrate 1, and an interference pattern is generated.The diffraction grating is then exposed by the interference pattern that is generated, and then developed and etched. can be formed. Here, the period Λ of the unevenness is determined by Λ=λ 0 /2sinα (1), where α is the incident angle of the laser beam 3.
一方、レーザの中央で回折格子の位相が反転し
た構造を有する回折格子を製造する方法として、
コンピユータ制御を用いた電子ビーム走査露光が
ある。この方法は、回折格子の溝に相当する部分
に順次電子ビームを走査して照射することにより
露光するものであるが、回折格子の周期Λが大き
い場合には適用できるが、凹凸の周期Λが結晶中
の光の波長λの半分である一次の回折格子のよう
に周期Λが小さい場合（約2000Å）には、解像度
の限界に達し、製造が実質上困難となつてしま
う。また、電子ビーム露光法は個別順次走査であ
るから、回折格子パターンの全面を走査し終るま
でにかなりの時間を必要とし、これを大量生産工
程に適用することは困難である。 On the other hand, as a method for manufacturing a diffraction grating having a structure in which the phase of the diffraction grating is inverted at the center of the laser,
There is electron beam scanning exposure using computer control. This method exposes the portions corresponding to the grooves of the diffraction grating by sequentially scanning and irradiating them with an electron beam. This method can be applied when the period Λ of the diffraction grating is large, but when the period Λ of the asperities is When the period Λ is small (approximately 2000 Å), such as in a first-order diffraction grating, which is half the wavelength λ of light in the crystal, the resolution reaches its limit and manufacturing becomes virtually difficult. Furthermore, since the electron beam exposure method involves individual sequential scanning, it takes a considerable amount of time to scan the entire surface of the diffraction grating pattern, making it difficult to apply this method to mass production processes.
次に、２光束干渉露光を用いて凹凸の位相が隣
接領域で互いに反転する構造を有する回折格子を
製造する場合の問題点について説明する。 Next, problems when manufacturing a diffraction grating having a structure in which the phases of concavities and convexities are reversed in adjacent regions using two-beam interference exposure will be described.
(1) 第２図は前述した２光束干渉露光により位相
が反転、すなわち180゜位相シフトした構造を有
する回折格子を製造した場合の模式図であり、
ＡとＢの領域をメタルマスクを用いて別々に露
光する方法である。同図は領域Ａに周期的な凹
凸を製造する場合を示しており、この時領域Ｂ
は厚さｔ（約50μｍ）のメタルマスク６により
覆われている。なお通常フオトレジスト膜２上
に隙間ｄ（約数μｍ）を設けている。干渉パタ
ーンが最も領域Ｂに近いところを示している
が、同図から明らかなようにレーザ光３はメタ
ルマスク６の厚さの影響により照射されない部
分、すなわち凹凸が全く製造されない領域Ｃが
できる。同様に領域Ａにメタルマスク６を施し
て領域Ｂに２光束干渉露光を行つても、凹凸が
製造されない領域Ｃができ、全体としては領域
Ｃの２倍に亘つて凹凸が形成されない。(1) Figure 2 is a schematic diagram of the case where a diffraction grating having a structure in which the phase is inverted, that is, the phase is shifted by 180°, is manufactured by the two-beam interference exposure described above.
This is a method in which areas A and B are exposed separately using metal masks. The figure shows a case where periodic unevenness is manufactured in area A, and at this time, area B
is covered with a metal mask 6 having a thickness of t (approximately 50 μm). Note that a gap d (about several μm) is usually provided on the photoresist film 2. The interference pattern is shown closest to region B, but as is clear from the figure, a region C is created where the laser beam 3 is not irradiated due to the influence of the thickness of the metal mask 6, that is, a region C where no unevenness is formed. Similarly, even if a metal mask 6 is applied to region A and two-beam interference exposure is performed to region B, a region C is formed in which no unevenness is formed, and as a whole, no unevenness is formed over twice as much as in region C.
例えば、回折格子の凹凸の周期Λを2400Åと
し、He−Cdレーザの波長λ0を3250Åとすれ
ば、入射角αは
α＝sin-1（λ0／2Λ）
＝sin-1（3250／4800）Å43〔度〕
となり、マスクの厚さｔを50μｍとし隙間をｄ
とすれば、周期的な凹凸が製造されない領域Ｃ
は
Ｃ＝（ｔ＋ｄ）tanαÅｔ・tanα＝47〔μｍ〕
となる。 For example, if the period Λ of the unevenness of the diffraction grating is 2400 Å and the wavelength λ 0 of the He-Cd laser is 3250 Å, the incident angle α is α = sin -1 (λ 0 /2Λ) = sin -1 (3250/4800 ) Å43 [degrees], and the mask thickness t is 50 μm and the gap is d.
Then, the region C where periodic irregularities are not produced
is C=(t+d)tanαÅt・tanα=47 [μm].
従つて、２回の２光束干渉露光により、凹凸
が形成されない領域Ｃの２倍の領域は94〔μｍ〕
となり、発光領域の全体長が通常数百〔μｍ〕
程度であることから、DFBレーザの動作電流
が大きくなり、また単一波長動作も不安定とな
る。この解決策として、メタルマスク６の厚さ
ｔを薄くしたり、メタルマスク６の内側端の上
面エツジに傾斜を設ければ若干改善ができる
が、やはり凹凸が形成されない領域Ｃができ
る。 Therefore, by two times of two-beam interference exposure, the area twice the area C where no unevenness is formed is 94 [μm].
Therefore, the total length of the light emitting region is usually several hundred [μm]
Because of this, the operating current of the DFB laser becomes large and single wavelength operation becomes unstable. As a solution to this problem, a slight improvement can be made by reducing the thickness t of the metal mask 6 or providing a slope to the upper surface edge of the inner end of the metal mask 6, but this still results in a region C where no unevenness is formed.
(2) 最初に領域Ａを露光し、次に領域Ｂを露光す
る時に凹凸の位相を180度反転させるため、基
板１を凹凸の周期Λの半分だけ（約1000Å）正
確に移動しなければならない。しかし、約1000
Å（0.1μｍ）だけ正確に基板１を移動させるこ
とは極めて難しく、再現性の面からも非常に困
難である。(2) In order to reverse the phase of the unevenness by 180 degrees when first exposing area A and then exposing area B, the substrate 1 must be accurately moved by half the period Λ of the unevenness (approximately 1000 Å). . But about 1000
It is extremely difficult to move the substrate 1 accurately by Å (0.1 μm), and it is also extremely difficult from the viewpoint of reproducibility.
以上のように、周期的な凹凸の位相が反転す
る構造を有する回折格子を従来の２光束干渉露
光で製造するのは困難であり、電子ビーム露光
法でも量産性の面で問題があつた。 As described above, it is difficult to manufacture a diffraction grating having a structure in which the phase of periodic asperities is inverted using conventional two-beam interference exposure, and even electron beam exposure has problems in terms of mass production.
（発明の目的と特徴）
本発明は、上述した従来の欠点を解消するため
になされたもので、電子ビーム露光に比べて簡便
でかつ量産性に優れた２光束干渉露光を用いて、
周期的な凹凸の位相が反転する構造の回折格子を
実現することのできる回折格子の製造方法を提供
することを目的とする。(Objectives and Features of the Invention) The present invention has been made to solve the above-mentioned conventional drawbacks, and uses two-beam interference exposure, which is simpler and easier to mass-produce than electron beam exposure.
It is an object of the present invention to provide a method for manufacturing a diffraction grating that can realize a diffraction grating having a structure in which the phase of periodic irregularities is inverted.
本発明の特徴は、感光特性が互いに反転した２
種類のフオトレジストを用いて、第１の領域及び
第２の領域で凹凸の位相が反転した回折格子を製
造する際に、分離膜を導入して両フオトレジスト
の混じり合いを防止することにより、どのような
フオトレジストの組合わせでも使用を可能にした
点にある。 The feature of the present invention is that two
When manufacturing a diffraction grating in which the phases of the concave and convex portions are reversed in the first region and the second region using different types of photoresists, a separation film is introduced to prevent the two photoresists from mixing. The advantage is that any combination of photoresists can be used.
（発明の構成及び作用） 以下に図面を用いて本発明を詳細に説明する。(Structure and operation of the invention) The present invention will be explained in detail below using the drawings.
実施例 １
第３図は本願の第１の発明による第１の実施例
であり、凹凸の位相が反転した構造を有する回折
格子の製造工程を概略的に示したものである。本
実施例では、第１のフオトレジストとしてポジタ
イプフオトレジストを用い、また第２のフオトレ
ジストとしてネガタイプフオトレジストを用い、
かつ分離膜としてSiN膜を用いた場合について述
べる。Embodiment 1 FIG. 3 is a first embodiment according to the first invention of the present application, which schematically shows the manufacturing process of a diffraction grating having a structure in which the phases of concave and convex portions are inverted. In this example, a positive type photoresist is used as the first photoresist, a negative type photoresist is used as the second photoresist,
We will also discuss the case where a SiN membrane is used as the separation membrane.
(1) 第１の工程
(a) 基板１上に第１のフオトレジストとしてポ
ジタイプフオトレジスト２（以後、「Ｐ膜」
と称す）を塗布した後、通常のフオトリソグ
ラフ法により、領域Ａにのみ残す。この際、
領域Ａに残されたポジタイプフオトレジスト
２は、未露光の状態のものである。(1) First step (a) A positive type photoresist 2 (hereinafter referred to as "P film") is deposited on the substrate 1 as the first photoresist.
) is applied, and then left only in area A by the usual photolithographic method. On this occasion,
The positive type photoresist 2 left in area A is in an unexposed state.
(b) 次に、基板１の全面に本発明の特徴に従つ
て分離膜、例えばSiN膜３を形成し、さらに
第２フオトレジストとしてネガタイプフオト
レジスト膜４（以後、「Ｎ膜」と称す）を全
面に塗布する。なお、、SiN膜３の形成には
室温での堆積が可能なECR法を用いること
により、Ｐ膜２への影響を極力小さくするこ
とができる。 (b) Next, a separation film, for example, a SiN film 3, is formed on the entire surface of the substrate 1 according to the characteristics of the present invention, and a negative type photoresist film 4 (hereinafter referred to as "N film") is further formed as a second photoresist. Apply to the entire surface. Note that by using the ECR method, which allows deposition at room temperature, to form the SiN film 3, the influence on the P film 2 can be minimized.
(2) 第２の工程
(c) 基板１の全面に一様な２光束干渉露光を行
う。図中、斜線部分は露光された部分を示し
ている。また、SiN膜３は光の透過度が良好
であるため、Ｐ膜２まで同時に露光すること
ができる。(2) Second step (c) Uniform two-beam interference exposure is performed over the entire surface of the substrate 1. In the figure, the shaded area indicates the exposed area. Furthermore, since the SiN film 3 has good light transmittance, even the P film 2 can be exposed at the same time.
(3) 第３の工程
(d) Ｎ膜４を現像することにより、一様なＮ膜
４の回折格子が形成される。(3) Third step (d) By developing the N film 4, a uniform diffraction grating of the N film 4 is formed.
(e) 次に、Ｎ膜４の回折格子をマスクとして領
域Ａ及び領域ＢのSiN膜３を緩衝フツ酸によ
り食刻する。 (e) Next, using the diffraction grating of the N film 4 as a mask, the SiN film 3 in regions A and B is etched with buffered hydrofluoric acid.
(f) さらに、領域ＡのＰ膜を現像することによ
り、領域Ａ及び領域Ｂで周期的な凹凸の位相
が互いに反転したＰ膜２及びSiN膜３の回折
格子が形成される。この際、SiN膜３及びＮ
膜４はリフトオフにより同時に除去すること
ができる。尚、Ｐ膜２の現像の際、領域Ｂの
SiN膜３上のＮ膜４が同時に除去されたり、
図中のように残存したりするが、いずれにし
ても本工程の成否に影響を与えるものではな
い。 (f) Furthermore, by developing the P film in the region A, a diffraction grating of the P film 2 and the SiN film 3 in which the phases of the periodic irregularities are reversed in the regions A and B is formed. At this time, the SiN film 3 and N
Membrane 4 can be removed at the same time by lift-off. In addition, when developing the P film 2, the area B
The N film 4 on the SiN film 3 is removed at the same time,
Although it may remain as shown in the figure, it does not affect the success or failure of this process in any case.
(g) 領域ＡのＰ膜２による回折格子と領域Ｂの
分離膜３による回折格子をそれぞれマスクと
して化学エツチングを行うことにより、中央
で凹凸の位相が反転した回折格子を基板１に
形成することができる。 (g) By performing chemical etching using the diffraction grating formed by the P film 2 in region A and the diffraction grating formed by the separation film 3 in region B as masks, a diffraction grating in which the phase of the unevenness is reversed at the center is formed on the substrate 1. Can be done.
なお、以上の説明では、第１のフオトレジスト
としてＰ膜２、第２のフオトレジストとしてＮ膜
４を用いたが、逆に第１のフオトレジストとして
Ｎ膜４、第２のフオトレジストとしてＰ膜２を用
いても良い。 In the above explanation, the P film 2 is used as the first photoresist and the N film 4 is used as the second photoresist. Membrane 2 may also be used.
実施例 ２
第４図は、本願の第１の発明による第２の実施
例であり、分離膜を一方の領域にのみ用いた場合
の製造工程の概略図である。Example 2 FIG. 4 is a second example according to the first invention of the present application, and is a schematic diagram of the manufacturing process when a separation membrane is used only in one region.
(1) 第１の工程
(a) 基板１上にＰ膜２を塗布した後、通常のフ
オトリソグラフ法により、領域Ａのみに残
し、次に全面にSiN膜３及びＮ膜４を順次形
成する。(1) First step (a) After coating the P film 2 on the substrate 1, leave it only in area A and then sequentially form the SiN film 3 and N film 4 on the entire surface using the usual photolithography method. .
(b) 通常のマスク露光により、領域Ｂのみを軽
く露光した後、領域ＡではＮ膜４を現像し、
これをマスクとしてSiN膜３をエツチング
し、Ｐ膜２のみを残す。尚、マスク露光の
際、露光時間を短くすることにより、現像後
にもほとんど未露光に近い特性を有するＮ膜
４を領域Ｂに残すことができる。 (b) After lightly exposing only area B by normal mask exposure, develop the N film 4 in area A,
Using this as a mask, the SiN film 3 is etched, leaving only the P film 2. In addition, by shortening the exposure time during mask exposure, the N film 4 having almost unexposed characteristics can be left in the region B even after development.
(2) 第２の工程
(c) 基板１の全面に、一様な２光束干渉露光を
行う。尚、斜線部は露光された部分を示して
いる。(2) Second step (c) Uniform two-beam interference exposure is performed on the entire surface of the substrate 1. Note that the shaded area indicates the exposed area.
(3) 第３の工程
(d) 領域ＢのＮ膜４を現像し、これをマスクと
して、SiN膜３をエツチングする。尚、高解
像性を有するノボラツク系ネガタイプフオト
レジストの現像液は、ポジタイプフオトレジ
スト用のものに比べ、通常PH値が小さいた
め、即ちアルカリ性が弱いので、Ｐ膜２はほ
とんど現像されない。また、もし現像された
としても支障はない。(3) Third step (d) N film 4 in region B is developed, and SiN film 3 is etched using this as a mask. Incidentally, since a developing solution for a novolak negative type photoresist having high resolution usually has a smaller pH value, that is, it is less alkaline than that for a positive type photoresist, the P film 2 is hardly developed. Moreover, even if it is developed, there will be no problem.
(e) 次に領域ＡのＰ膜２を現像する。この際、
上記、ネガタイプフオトレジスト及びポジタ
イプフオトレジスト現象液のPH値の違いによ
りＮ膜４が除去される場合があるが、何ら問
題なく、また、例えＮ膜４がSiN膜３上に残
存したとしても問題がないことは言うまでも
ない。以上の工程により、領域Ａ及び領域Ｂ
で、その周期的凹凸の位相が互いに反転した
各々Ｐ膜及びSiN膜３の回折格子が形成され
るわけである。 (e) Next, the P film 2 in area A is developed. On this occasion,
As mentioned above, the N film 4 may be removed due to the difference in PH value between the negative type photoresist and the positive type photoresist phenomenon liquid, but there is no problem and even if the N film 4 remains on the SiN film 3. Needless to say, there are no problems. Through the above steps, area A and area B
Thus, a diffraction grating is formed of the P film and the SiN film 3 in which the phases of the periodic irregularities are inverted with each other.
(f) これらをマスクとして化学エツチングを行
うことにより、中央で凹凸の位相が反転した
回折格子付基板１が得られる。 (f) By performing chemical etching using these as a mask, a substrate 1 with a diffraction grating in which the phase of the unevenness is reversed at the center can be obtained.
実施例 ３
第５図は本願の第２の発明による実施例であ
り、Ｐ膜２とＮ膜４の両方を用いた領域にのみ分
離膜を用い、かつ実施例１の第１のフオトレジス
ト及び第２のフオトレジストを逆にした場合の製
造工程の概略図である。Example 3 FIG. 5 is an example according to the second invention of the present application, in which a separation film is used only in the region where both the P film 2 and the N film 4 are used, and the first photoresist and the first photoresist of Example 1 are used. FIG. 6 is a schematic diagram of the manufacturing process when the second photoresist is reversed.
(1) 第１の工程
(a) 基板１の全面にＮ膜４、SiN膜３及びＰ膜
２を順次形成し、領域Ｂのみ通常のマスク露
光を行う。なお、図中斜線部分が露光されて
いる。(1) First step (a) N film 4, SiN film 3, and P film 2 are sequentially formed on the entire surface of substrate 1, and only region B is subjected to normal mask exposure. Note that the shaded area in the figure is exposed.
(b) 領域ＢのみＰ膜２の現像、SiN膜３及びＮ
膜４のエツチングを行つたのち、基板１の全
面に再度Ｐ膜２ａを塗布する。この際、領域
Ａでは従来のＰ膜２と塗布しなおしたＰ膜２
ａとが混り合い、Ｐ膜２ａのみが形成された
ようになる。但し、説明を解り易くするた
め、Ｐ膜２とＰ膜２ａとの異なつた記号を用
いたが同一のポジタイプフオトレジストであ
る。 (b) Development of P film 2 only in area B, SiN film 3 and N
After etching the film 4, the entire surface of the substrate 1 is again coated with the P film 2a. At this time, in area A, the conventional P film 2 and the reapplied P film 2
The P film 2a is mixed with the P film 2a, so that only the P film 2a is formed. However, in order to make the explanation easier to understand, different symbols are used for the P film 2 and the P film 2a, but they are the same positive type photoresist.
(2) 第２の工程
(c) 基板１の全面に一様な２光束干渉露光を行
う。(2) Second step (c) Uniform two-beam interference exposure is performed over the entire surface of the substrate 1.
(3) 第３の工程
(d) 両領域のＰ膜２ａを現像し、領域Ａ及び領
域Ｂの表面にＰ膜２ａの回折格子を形成す
る。(3) Third step (d) The P film 2a in both regions is developed to form a diffraction grating of the P film 2a on the surfaces of region A and region B.
(e) 領域ＡのSiN膜３をエツチングにより完全
に除去する。 (e) Completely remove the SiN film 3 in area A by etching.
(f) 領域ＡのＮ膜４を現像する。以上の工程
で、領域Ａ及び領域Ｂで、その周期的凹凸の
位相が互いに反転した各々Ｎ膜４及びＰ膜２
ａの回折格子が形成されるわけである。 (f) Develop the N film 4 in area A. In the above process, in the region A and the region B, the N film 4 and the P film 2 whose periodic irregularities have mutually reversed phases are formed.
Thus, a diffraction grating of a is formed.
(g) これらをマスクとして化学エツチングを行
うことにより、中央で凹凸の位相が反転した
回折格子付基板１が得られる。 (g) By performing chemical etching using these as a mask, a substrate 1 with a diffraction grating in which the phase of the unevenness is reversed at the center can be obtained.
以上のように、本発明により、ネガタイプ及び
ボジタイプフオトレジスト間に分離膜を介在させ
ることにより、そのままでは、混り易いフオトレ
ジストの組合わせを用いても、左右の凹凸の位相
が反転した構造を有する回折格子を製造すること
ができる。尚、以上の実施例では、分離膜として
SiN膜を用いて説明したが、代りにSiO2膜などの
誘電体膜、金属、もしくはフオトレジストとの混
り合いのない有機物薄膜を用いることも可能であ
る。 As described above, according to the present invention, by interposing a separation film between a negative type photoresist and a positive type photoresist, a structure in which the phase of the left and right unevenness is reversed even if a combination of photoresists that are easily mixed together is used. It is possible to manufacture a diffraction grating having: In addition, in the above examples, as a separation membrane,
Although the description has been made using a SiN film, it is also possible to use a dielectric film such as a SiO 2 film, a metal, or an organic thin film that does not mix with photoresist.
（発明の効果）
以上の工程から明らかなように、本発明ではそ
のまま重ね塗つたのでは混り合つてしまい高解像
性を有するノボラツク系ポジタイプ及びネガタイ
プフオトレジストを同時に使用できるようにネガ
タイプとポジタイプフオトレジストとの間に分離
膜を挿入することにより、製作が容易でかつ高解
像度の左右の凹凸が反転した回折格子が製造でき
る。従つて、安定でかつ特性の良いDFBレーザ
等に応用ができその効果は極めて大である。(Effects of the Invention) As is clear from the above steps, in the present invention, if the layers are coated directly, they will get mixed up, so the negative type and positive type photoresists can be used at the same time. By inserting a separation film between the photoresist and the photoresist, it is possible to manufacture a diffraction grating that is easy to manufacture and has high resolution and inverted left and right unevenness. Therefore, it can be applied to DFB lasers, etc., which are stable and have good characteristics, and the effect is extremely large.
第１図は従来の２光束干渉露光法の原理図、第
２図は従来の２光束干渉露光により部分的に凹凸
の位相が反転する回折格子製造の模式図、第３
図、第４図及び第５図は本発明による回折格子の
製造工程を説明する断面図である。
１……基板、２，２ａ……ポジタイプフオトレ
ジスト、３……SiN膜、４……ネガタイプフオト
レジスト。
Figure 1 is a principle diagram of the conventional two-beam interference exposure method, Figure 2 is a schematic diagram of the manufacturing of a diffraction grating in which the phase of the concave and convex portions is partially reversed by conventional two-beam interference exposure, and Figure 3
4 and 5 are cross-sectional views illustrating the manufacturing process of a diffraction grating according to the present invention. 1... Substrate, 2, 2a... Positive type photoresist, 3... SiN film, 4... Negative type photoresist.
Claims (1)
トレジスト膜を形成し該第１の領域とは別の第２
の領域には分離膜及び第１のフオトレジストと感
光特性が反転した第２のフオトレジスト膜を順次
形成する第１の工程と、前記基板に２光束干渉露
光を行う第２の工程と、該第２のフオトレジスト
の現像、分離膜のエツチング、第１のフオトレジ
ストの現像を各々行うことにより、第１の領域で
は第１のフオトレジストの回折格子、第２の領域
では少なくとも該分離膜による回折格子が形成さ
れ、前記第１の領域の第１のフオトレジストによ
る回折格子と前記第２の領域の分離膜による回折
格子をそれぞれをマスクとして、該基板上に第１
と第２の領域で凹凸の位相が互いに反転した回折
格子を形成する第３の工程とを含む回折格子の製
造方法。 ２ 基板上の第１の領域にネガタイプフオトレジ
スト膜及び分離膜を形成しさらに第１及び第２の
領域を含む基板全面にポジタイプフオトレジスト
膜を形成する第１の工程と、前記基板上に２光束
干渉露光を行う第２の工程と、該ポジタイプフオ
トレジストの現像、分離膜のエツチング、ネガタ
イプフオトレジストの現像を各々行うことによ
り、第１の領域ではネガタイプフオトレジストの
回折格子、第２の領域ではポジタイプフオトレジ
ストの回折格子が形成され、これをマスクとして
該基板上に第１の領域と第２の領域で凹凸の位相
が互いに反転した回折格子を形成する第３の工程
とを含む回折格子の製造方法。 ３ 前記分離膜として、誘電体、金属もしくは有
機物を用いることを特徴とする特許請求の範囲第
１項及び第２項記載の回折格子の製造方法。[Scope of Claims] 1. Forming at least a first photoresist film in a first region on a substrate, and forming a second photoresist film different from the first region.
a first step of sequentially forming a separation film and a second photoresist film having photosensitive characteristics inverted to those of the first photoresist in the region; a second step of performing two-beam interference exposure on the substrate; By developing the second photoresist, etching the separation film, and developing the first photoresist, the diffraction grating of the first photoresist is formed in the first region, and at least the separation film is formed in the second region. A diffraction grating is formed on the substrate using the diffraction grating formed by the first photoresist in the first region and the diffraction grating formed by the separation film in the second region as masks.
and a third step of forming a diffraction grating in which the phases of the concave and convex portions are inverted with respect to each other in the second region. 2. A first step of forming a negative type photoresist film and a separation film on a first region on the substrate, and further forming a positive type photoresist film on the entire surface of the substrate including the first and second regions, and By performing a second step of two-beam interference exposure, developing the positive type photoresist, etching the separation film, and developing the negative type photoresist, in the first area, the diffraction grating of the negative type photoresist, the second A diffraction grating of positive type photoresist is formed in the region, and a third step is performed in which a diffraction grating is formed on the substrate using this as a mask, in which the phases of the projections and recesses are reversed in the first region and the second region. A method of manufacturing a diffraction grating comprising: 3. The method for manufacturing a diffraction grating according to claims 1 and 2, wherein a dielectric, metal, or organic material is used as the separation film.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15523685A JPS6217702A (en) | 1985-07-16 | 1985-07-16 | Production of diffraction grating |
| US06/882,588 US4826291A (en) | 1985-07-16 | 1986-07-07 | Method for manufacturing diffraction grating |
| GB8617156A GB2178192B (en) | 1985-07-16 | 1986-07-15 | Method for manufacturing diffraction grating |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15523685A JPS6217702A (en) | 1985-07-16 | 1985-07-16 | Production of diffraction grating |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6217702A JPS6217702A (en) | 1987-01-26 |
| JPH0323884B2 true JPH0323884B2 (en) | 1991-03-29 |
Family
ID=15601510
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15523685A Granted JPS6217702A (en) | 1985-07-16 | 1985-07-16 | Production of diffraction grating |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6217702A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2730893B2 (en) * | 1987-06-24 | 1998-03-25 | 三菱電機株式会社 | Diffraction grating manufacturing method |
| US4842633A (en) * | 1987-08-25 | 1989-06-27 | Matsushita Electric Industrial Co., Ltd. | Method of manufacturing molds for molding optical glass elements and diffraction gratings |
-
1985
- 1985-07-16 JP JP15523685A patent/JPS6217702A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6217702A (en) | 1987-01-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4660934A (en) | Method for manufacturing diffraction grating | |
| US5225039A (en) | Method for producing a diffraction grating | |
| US4826291A (en) | Method for manufacturing diffraction grating | |
| JPS61190368A (en) | Formation of fine pattern | |
| EP0566886B1 (en) | Method of producing diffraction grating | |
| US5221429A (en) | Method of manufacturing phase-shifted diffraction grating | |
| JPH0323884B2 (en) | ||
| JPH0461331B2 (en) | ||
| JPH052201B2 (en) | ||
| JPH0374805B2 (en) | ||
| JP2527833B2 (en) | Method of manufacturing diffraction grating | |
| EP0490320B1 (en) | A method for producing a diffraction grating | |
| JPS627001A (en) | Production of diffraction grating | |
| JPH0374804B2 (en) | ||
| JPH0361901A (en) | Production of lambda/4 shift diffraction grating | |
| JP2786229B2 (en) | Manufacturing method of diffraction grating | |
| JPH01224767A (en) | Formation of resist pattern | |
| JPS61292923A (en) | Formation of phase inversion type pattern | |
| JPS62165392A (en) | Manufacture of diffraction grating | |
| JPH05343806A (en) | Manufacture of phase-shifting diffraction | |
| JPH02213182A (en) | Manufacture of diffraction grating | |
| JPH0690323B2 (en) | Method of manufacturing diffraction grating | |
| JPH01225189A (en) | Manufacture of diffraction grating | |
| JPS6370477A (en) | Manufacture of phase shift type diffraction grating | |
| JPH02154204A (en) | Manufacture of diffraction grating |