JPH06209126A - Selective etching material and method for oxide superconductor thin film - Google Patents
Selective etching material and method for oxide superconductor thin filmInfo
- Publication number
- JPH06209126A JPH06209126A JP5003002A JP300293A JPH06209126A JP H06209126 A JPH06209126 A JP H06209126A JP 5003002 A JP5003002 A JP 5003002A JP 300293 A JP300293 A JP 300293A JP H06209126 A JPH06209126 A JP H06209126A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- oxide
- etching
- oxide superconductor
- superconductor thin
- Prior art date
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、酸化物超伝導体薄膜の
湿式エッチングにおけるエッチング材料及びエッチング
方法に係り、特に、酸化物絶縁膜をエッチングすること
なく酸化物超伝導体薄膜のみをエッチングする選択エッ
チング材料及びエッチング方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching material and an etching method for wet etching of an oxide superconductor thin film, and particularly to etching only an oxide superconductor thin film without etching an oxide insulating film. The present invention relates to a selective etching material and an etching method.
【０００２】[0002]
【従来の技術】1986年に発見された La1-xMxCuO4-y(M :
Sr、Ba、0＜x＜1)は超伝導転移温度(Tc)が 30〜40K と
従来の金属超伝導体の Tc と比較して著しく高いことか
ら、酸化物超伝導体の探求が進められ、Tc 90Kを有する
LnBa2Cu3Ox酸化物超伝導体(Ln: Y 及びランタニド元
素)、Tc 110Kを有する BiSrCaCuOx系酸化物超伝導体、T
c120Kを有する TlBaCaCuOx系酸化物超伝導体の発見が相
次いだ。その後、これらの薄膜を用いたデバイスとし
て、フィルター、レゾネーター等のマイクロ波デバイ
ス、粒界接合 SQUID 、ブリッジ等のアクティブデバイ
スが作られている。これらのデバイス作製時に酸化物超
伝導体薄膜をパターニングする際のエッチング方法には
二通りの方法があり、その一つは例えば真空中で加速し
た Ar を超伝導体薄膜に照射してミリングする方法(乾
式エッチング法)、他の一つは例えば希釈した硝酸でエ
ッチングする方法(湿式エッチング法)である。現在まで
これらの方法によって酸化物超伝導体薄膜の加工が行わ
れてきた。2. Description of the Related Art La 1-x M x CuO 4-y (M:
The superconducting transition temperature (Tc) of Sr, Ba and 0 <x <1) is 30 to 40K, which is significantly higher than that of conventional metal superconductors. Therefore, the search for oxide superconductors has been promoted. , With Tc 90K
LnBa 2 Cu 3 O x oxide superconductor (Ln: Y and lanthanide element), BiSrCaCuO x oxide superconductor with Tc 110 K, T
The discovery of TlBaCaCuO x oxide superconductors with c120K was one after another. Later, as devices using these thin films, microwave devices such as filters and resonators, active devices such as grain boundary junction SQUIDs and bridges were created. There are two etching methods for patterning oxide superconductor thin films during the fabrication of these devices, one of which is, for example, a method of irradiating Ar accelerated in a vacuum on a superconductor thin film and performing milling. (Dry etching method), and the other one is a method of etching with diluted nitric acid (wet etching method). Until now, oxide superconductor thin films have been processed by these methods.
【０００３】ところが、超伝導集積回路の基本デバイス
となる超伝導体/絶縁体/超伝導体の積層構造(いわゆる
ジョセフソン接合)の作製時にこれらのエッチング方法
を用いると、例えば Ar ミリングでは、積層構造の上部
電極となる超伝導体表面からミリングし始め、上部電極
となる超伝導体、絶縁層となる絶縁体極薄膜まで切り込
むことが必要となる。ところが、超伝導体と絶縁体のミ
リング速度が極端には違わないことと、通常、ミリング
速度にばらつきがあるため、ミリング時間のみで極薄膜
のところまでミリングされたと計算すると、上部電極と
なる超伝導体が残っている可能性が高い。そこで、通
常、下部電極となる超伝導体中央部までミリングするこ
とが必要となる。しかしながら、下部電極となる超伝導
体中央部でミリングを止めることは技術的に難しい。ま
た、高エネルギーの Ar を超伝導体に照射するため、ミ
リング時のダメージによって酸化物超伝導体の超伝導特
性が失われるという問題点があった。However, if these etching methods are used when a superconductor / insulator / superconductor laminated structure (so-called Josephson junction), which is a basic device of a superconducting integrated circuit, is used, for example, in Ar milling, laminated layers are formed. It is necessary to start milling from the surface of the superconductor that will be the upper electrode of the structure, and cut into the superconductor that will be the upper electrode and the insulator ultrathin film that will be the insulating layer. However, since the milling speeds of the superconductor and the insulator are not extremely different and the milling speed is usually different, it is calculated that the ultrathin film is milled only by the milling time. The conductor is likely to remain. Therefore, it is usually necessary to perform milling up to the central portion of the superconductor which will be the lower electrode. However, it is technically difficult to stop the milling at the central part of the superconductor which will be the lower electrode. Moreover, since the superconductor is irradiated with high-energy Ar, the superconducting properties of the oxide superconductor are lost due to damage during milling.
【０００４】一方、湿式エッチング法の場合には、通常
酸化物超伝導体薄膜の湿式エッチングに用いられるエッ
チング液として希釈硝酸、希釈塩酸がある。これらを用
いて積層構造の上部電極となる酸化物超伝導体薄膜をエ
ッチングすると、積層構造の上部電極となる超伝導体薄
膜はおろか絶縁体極薄膜、さらに下部電極となる超伝導
体薄膜までもが数秒の内にエッチングされる。すなわ
ち、積層構造を形成するジョセフソン接合部分の周囲が
全てエッチングされ、上部電極から入った電気信号が流
れ出す配線がないという重大な問題点が生じていた。On the other hand, in the case of the wet etching method, dilute nitric acid and dilute hydrochloric acid are usually used as the etching solution for the wet etching of the oxide superconductor thin film. When the oxide superconductor thin film that becomes the upper electrode of the laminated structure is etched using these, not only the superconductor thin film that becomes the upper electrode of the laminated structure but also the insulator ultra-thin film and even the superconductor thin film that becomes the lower electrode Are etched within a few seconds. That is, there has been a serious problem that the entire periphery of the Josephson junction portion forming the laminated structure is etched, and there is no wiring through which an electric signal entered from the upper electrode flows out.
【０００５】[0005]
【発明が解決しようとする課題】以上述べたように、従
来技術は種々の問題点を有していた。As described above, the prior art has various problems.
【０００６】本発明の目的は、上記従来技術の有してい
た課題を解決して、酸化物絶縁体極薄膜上の酸化物超導
電体薄膜をエッチングする材料及びエッチング方法とし
て、酸化物絶縁体極薄膜をエッチングすることなく、酸
化物超伝導体薄膜のみをエッチングすることのできる選
択エッチング材料及び選択エッチング方法を提供するこ
とにある。An object of the present invention is to solve the above problems of the prior art and to provide a material and etching method for etching an oxide superconductor thin film on an oxide insulator ultrathin film. An object of the present invention is to provide a selective etching material and a selective etching method capable of etching only an oxide superconductor thin film without etching an extremely thin film.
【０００７】[0007]
【課題を解決するための手段】上記目的は、基板上に酸
化物超伝導体薄膜、酸化物絶縁膜、酸化物超伝導体薄膜
を順次形成してなる積層構造体のエッチングにおいて、
酸化物絶縁膜をエッチングすることなく最上層酸化物超
伝導体のみをエッチングするエッチング材料がカルボン
酸を含有していることを特徴とする酸化物超伝導体薄膜
の選択エッチング材料とすること及びこれを用いたエッ
チング方法とすることによって達成することができる。Means for Solving the Problems The above-mentioned object is to etch a laminated structure formed by sequentially forming an oxide superconductor thin film, an oxide insulating film, and an oxide superconductor thin film on a substrate,
A selective etching material for an oxide superconductor thin film, characterized in that the etching material for etching only the uppermost oxide superconductor without etching the oxide insulating film contains a carboxylic acid, and It can be achieved by using an etching method using.
【０００８】[0008]
【作用】本発明では、酸化物超伝導体薄膜/酸化物絶縁
体極薄膜/酸化物超伝導体薄膜の積層構造からなるいわ
ゆるジョセフソン接合の上部電極となる最表面の酸化物
超伝導薄膜を湿式エッチングによって同一基板内の幾つ
かの上部電極に分割させるとき、上部電極と下部電極と
の間に形成されている絶縁体薄膜をエッチングすること
のないエッチング材料を用いているため、上部電極とな
る超伝導体薄膜のみを幾つかに分割することができる。
そのため、その内の一つの上部電極から注入した電流は
その上部電極から絶縁体極薄膜中をトンネルして下部電
極に達し、下部電極中を流れて最初に入った上部電極と
は異なる上部電極と接している絶縁体極薄膜中をもう一
度トンネルし、その異なる上部電極に出るという回路が
成立し、ジョセフソン接合として動作するという特徴が
得られる。In the present invention, the oxide superconducting thin film on the outermost surface, which is the upper electrode of a so-called Josephson junction, having a laminated structure of an oxide superconducting thin film / oxide insulating ultrathin film / oxide superconducting thin film is formed. When divided into several upper electrodes in the same substrate by wet etching, an etching material that does not etch the insulator thin film formed between the upper and lower electrodes is used. Can be divided into several.
Therefore, the current injected from one of the upper electrodes tunnels from the upper electrode to the lower electrode through the insulator ultrathin film, flows through the lower electrode, and flows into the upper electrode that is different from the first upper electrode that entered. A circuit is established in which a tunnel is made again in the insulating ultrathin film that is in contact with the thin film, and the different upper electrode is formed, and the circuit operates as a Josephson junction.
【０００９】一方、従来技術における、例えば、水希釈
の１％硝酸あるいは塩酸をエッチング材料として用いる
湿式エッチングでは、酸化物超伝導体薄膜/酸化物絶縁
体極薄膜/酸化物超伝導体薄膜の積層構造からなるいわ
ゆるジョセフソン接合の上部電極となる最表面の酸化物
超伝導体薄膜をエッチングによって同一基板内の幾つか
の上部電極に分割させるとき、上部電極の酸化物超伝導
体はおろか酸化物絶縁体薄膜、さらに下部電極の酸化物
超伝導体薄膜までも数秒の内にエッチングしてしまうた
め、積層構造をした各ジョセフソン接合は個々に電気的
に分離する。この状態で一つの上部電極から電流を注入
しようとすると、電流は上部電極から絶縁体極薄膜をト
ンネルし、下部電極に至った後、流れ出る配線がない状
態が生じる。すなわち、このエッチング液を用いると、
作製したジョセフソン接合は常に断線するという重大な
問題点がある。On the other hand, in the prior art, for example, in wet etching using 1% nitric acid or hydrochloric acid diluted with water as an etching material, a stack of oxide superconductor thin film / oxide insulator ultrathin film / oxide superconductor thin film is laminated. When the outermost oxide superconductor thin film, which is the upper electrode of the so-called Josephson junction made of a structure, is divided into several upper electrodes on the same substrate by etching, the oxide superconductor of the upper electrode is not an oxide. Since the insulator thin film and the oxide superconductor thin film of the lower electrode are also etched within a few seconds, each Josephson junction having a laminated structure is electrically isolated. If an electric current is attempted to be injected from one upper electrode in this state, the electric current tunnels through the insulating ultrathin film from the upper electrode, and after reaching the lower electrode, there is no wiring flowing out. That is, using this etching solution,
The produced Josephson junction has a serious problem that it always breaks.
【００１０】[0010]
【実施例】以下本発明の選択エッチング材料及びこれを
用いたエッチング方法について実施例によって具体的に
説明する。EXAMPLES The selective etching material of the present invention and the etching method using the same will be specifically described below with reference to examples.
【００１１】[0011]
【実施例１】本実施例は酸化物超伝導体のエッチング液
として本発明の希釈カルボン酸を用いた場合と従来技術
の希釈硝酸を用いた場合との対比を示すものであるが、
図１〜４によって説明する。なお、図中で、１は基板、
２は例えば YBa2Cu3Ox 超伝導薄膜(下部電極)、３は例
えば酸化物絶縁体の PrGaO3 、４は例えば YBa2Cu3O
x(上部電極)、５は例えば AZ1350 レジストを示す。Example 1 This example shows a comparison between the case where the diluted carboxylic acid of the present invention is used as an etchant for an oxide superconductor and the case where diluted nitric acid of the prior art is used.
This will be described with reference to FIGS. In the figure, 1 is a substrate,
2 is, for example, YBa 2 Cu 3 O x superconducting thin film (lower electrode), 3 is, for example, PrGaO 3 , which is an oxide insulator, and 4 is, for example, YBa 2 Cu 3 O.
x (upper electrode), 5 indicates, for example, AZ1350 resist.
【００１２】図１は基板１上に下部電極となる酸化物超
伝導薄膜例えば YBa2Cu3Ox薄膜２を堆積した状態を示す
図である。対比実験に用いたエッチング液はそれぞれ水
希釈の１％酢酸と１％硝酸である。これらのエッチング
液中に図１の酸化物超伝導薄膜を浸漬したところ、エッ
チング速度は希釈酢酸中では約130Å/sec、希釈硝酸中
では約700Å/secであった。これと同一条件の下で、図
２に示す試料を用いて対比実験を行った。図２に示す試
料とは、基板１上に下部電極となる酸化物超伝導薄膜 Y
Ba2Cu3Ox薄膜２を500Å堆積し、その上に酸化物絶縁体
極薄膜 PrGaO3薄膜３を50Å堆積し、その上に上部電極
となる酸化物超伝導薄膜 YBa2Cu3Oxを５００Å堆積し、
さらにその上にレジスト５を数箇所に塗布したものであ
る。これを希釈酢酸中に１６秒間浸漬した結果を図３
に、希釈硝酸中に２秒間浸漬した結果を図４に示す。FIG. 1 is a view showing a state in which an oxide superconducting thin film, for example, a YBa 2 Cu 3 O x thin film 2 which will be a lower electrode is deposited on a substrate 1. The etching solutions used in the comparison experiment were 1% acetic acid and 1% nitric acid diluted with water, respectively. When the oxide superconducting thin film of FIG. 1 was immersed in these etching solutions, the etching rate was about 130Å / sec in diluted acetic acid and about 700Å / sec in diluted nitric acid. Under the same conditions as this, a comparison experiment was performed using the sample shown in FIG. The sample shown in FIG. 2 is the oxide superconducting thin film Y that will be the lower electrode on the substrate 1.
Ba 2 Cu 3 O x thin film 2 is deposited on 500 Å, oxide insulator ultra-thin film PrGaO 3 thin film 50 is deposited on it, and oxide superconducting thin film YBa 2 Cu 3 O x to be the upper electrode is deposited on it. 500 Å deposited,
Further, the resist 5 is applied on several places thereon. The result of immersing this in diluted acetic acid for 16 seconds is shown in FIG.
FIG. 4 shows the result of immersion in diluted nitric acid for 2 seconds.
【００１３】まず、図４の場合、導通試験により各積層
構造が下部電極の酸化物超伝導体薄膜２で電気的につな
がっていないことが、また、顕微鏡観察により酸化物超
伝導薄膜４/酸化物絶縁体極薄膜３/酸化物超伝導体薄膜
２が全てエッチングされていることが判った。すなわ
ち、このエッチング液を用いると、作製したジョセフソ
ン接合は常に断線することが確認された。一方、希釈酢
酸中浸漬の試料は、上部電極となる酸化物超伝導体薄膜
４はエッチングされていたが、その下の酸化物絶縁体極
薄膜３及び下部電極となる酸化物超伝導体薄膜２はエッ
チングされていないことが顕微鏡観察により、また、導
通試験により下部電極となる酸化物超伝導体薄膜２が電
気的につながっていることが確認された。すなわち、本
発明のエッチング材料を用いることによって、エッチン
グが酸化物絶縁体極薄膜３で止まり、それ以上エッチン
グが進行しないために、酸化物絶縁体極薄膜３の下の酸
化物超伝導体薄膜２がエッチングされず、ジョセフソン
接合が電気的に断線しないことが確認された。First, in the case of FIG. 4, it is confirmed by the continuity test that the laminated structures are not electrically connected to each other by the oxide superconductor thin film 2 of the lower electrode. It was found that the insulator thin film 3 / oxide superconductor thin film 2 was entirely etched. That is, it was confirmed that the Josephson junction produced was always broken when this etching solution was used. On the other hand, in the sample immersed in diluted acetic acid, the oxide superconductor thin film 4 serving as the upper electrode was etched, but the oxide insulator ultrathin film 3 thereunder and the oxide superconductor thin film 2 serving as the lower electrode were formed. It was confirmed by microscope observation that the oxide superconductor was not etched, and by the continuity test that the oxide superconductor thin film 2 serving as the lower electrode was electrically connected. That is, when the etching material of the present invention is used, the etching stops at the oxide insulator ultrathin film 3 and the etching does not proceed any further. Therefore, the oxide superconductor thin film 2 under the oxide insulator ultrathin film 3 is prevented. Was not etched, and it was confirmed that the Josephson junction was not electrically disconnected.
【００１４】なお、上記例では希釈カルボン酸として水
希釈の１％酢酸を用いた場合について説明したが、希釈
率を変えても、あるいは他のカルボキシル基を持つ酸を
用いた場合にも同様の効果が得られた。In the above example, the case where 1% acetic acid diluted with water was used as the diluting carboxylic acid, but the same applies to the case where the dilution ratio is changed or the acid having another carboxyl group is used. The effect was obtained.
【００１５】[0015]
【実施例２】本実施例においては、酸化物超伝導体薄膜
/酸化物絶縁体極薄膜/酸化物超伝導体薄膜積層構造のい
わゆるジョセフソン接合を作製する場合に本発明の選択
エッチング材料を用いたときの一連の工程について説明
する。図５〜９によって説明するが、図中１は基板、２
は例えば YBa2Cu3Ox超伝導薄膜下部電極、３は例えば酸
化物絶縁体 PrGaO3薄膜、４は上部電極 YBa2Cu3Ox薄
膜、５は例えば AZ1350レジスト、６はホトマスク、７
は層間絶縁膜例えば SiOx、８は配線の例えば金を示
す。Example 2 In this example, an oxide superconductor thin film is used.
A series of steps when the selective etching material of the present invention is used in producing a so-called Josephson junction of / oxide insulator ultrathin film / oxide superconductor thin film laminated structure will be described. The description will be made with reference to FIGS.
Is a YBa 2 Cu 3 O x superconducting thin film lower electrode, 3 is an oxide insulator PrGaO 3 thin film, 4 is an upper electrode YBa 2 Cu 3 O x thin film, 5 is an AZ1350 resist, 6 is a photomask, 7
Indicates an interlayer insulating film such as SiO x , and 8 indicates a wiring such as gold.
【００１６】図５に、基板１上に下部電極となる酸化物
超伝導体薄膜である YBa2Cu3Ox薄膜２を堆積し、その上
に酸化物絶縁体極薄膜である PrGaO3薄膜３を堆積し、
その上に下部電極となる酸化物超伝導薄膜 YBa2Cu3Ox薄
膜４を堆積し、さらにその上にレジスト５を塗布し、そ
の上にマスク６を載せた状態を示す。次に、マスク以外
の部分を露光し、例えばブロムベンゼンによって表面を
固化させた後(これによって庇が形成される)、現像した
状態を図６に示す。次に、現像したレジスト５をマスク
として上部電極４となる YBa2Cu3Ox薄膜を水による酢酸
の１％希釈液でエッチングした状態を図７に示す。次
に、現像したレジスト５をマスクとして層間絶縁膜７の
SiOxを堆積後、リフトオフプロセスによってレジスト
５及びレジスト５上に堆積した層間絶縁膜７を除去した
状態を図８に示す。最後に、リフトオフプロセスにより
配線８の金を上部電極４を覆う部分に堆積すると、図９
に示すように、配線８の金から上部電極４の YBa2Cu
3Ox、絶縁層の PrGaO3薄膜３、下部電極２となる YBa2C
u3Ox薄膜に至る部分が所望の酸化物超伝導体/酸化物絶
縁体/酸化物超伝導体となるジョセフソン接合を実現す
ることができる。In FIG. 5, a YBa 2 Cu 3 O x thin film 2 which is an oxide superconductor thin film to be a lower electrode is deposited on a substrate 1, and a PrGaO 3 thin film 3 which is an oxide insulator ultrathin film 3 is deposited thereon. Deposited,
A state is shown in which an oxide superconducting thin film YBa 2 Cu 3 O x thin film 4 to be a lower electrode is deposited thereon, a resist 5 is further applied thereon, and a mask 6 is placed thereon. Next, FIG. 6 shows a state in which a portion other than the mask is exposed to light, the surface is solidified with, for example, brombenzene (this forms an eaves), and then developed. Next, FIG. 7 shows a state in which the YBa 2 Cu 3 O x thin film to be the upper electrode 4 was etched with a 1% dilute solution of acetic acid with water using the developed resist 5 as a mask. Next, the developed resist 5 is used as a mask to form the interlayer insulating film 7.
FIG. 8 shows a state in which the resist 5 and the interlayer insulating film 7 deposited on the resist 5 are removed by a lift-off process after depositing SiO x . Finally, gold of the wiring 8 is deposited on the portion covering the upper electrode 4 by the lift-off process.
As shown in the figure, from the gold of the wiring 8 to the YBa 2 Cu of the upper electrode 4.
3 O x , PrGaO 3 thin film 3 for insulating layer, YBa 2 C to be the lower electrode 2
It is possible to realize a Josephson junction in which a portion reaching the u 3 O x thin film becomes a desired oxide superconductor / oxide insulator / oxide superconductor.
【００１７】なお、上記の例においては超伝導体薄膜と
して YBa2Cu3Ox、酸化物絶縁体薄膜として PrGaO3、ま
た、エッチング液の希釈カルボン酸として水希釈の１％
酢酸を用いた場合について説明したが、例えば BiSrCaC
uOx系、TlBaCaCuOx系等の酸化物超伝導薄膜を用いて
も、酸化物絶縁体薄膜のエッチング速度と大きな差があ
れば同じ効果が得られることは言うまでもない。In the above example, the superconductor thin film is YBa 2 Cu 3 O x , the oxide insulator thin film is PrGaO 3 , and the diluted carboxylic acid of the etching solution is 1% of water dilution.
The case of using acetic acid was explained, but for example, BiSrCaC
uO x system, be an oxide superconducting thin TlBaCaCuO x system or the like, the same effect can be obtained if there is a large difference between the etching rates of the oxide insulator thin film of course.
【００１８】[0018]
【実施例３】図10に酸化物超伝導体配線/酸化物絶縁体
層間絶縁膜/酸化物超伝導体グランドプレーン積層構造
を示す図で、１は基板、２は例えばグランドプレーンと
なる YBa2Cu3Ox超伝導薄膜、９は例えば酸化物絶縁体の
PrGaO3、４は例えば超伝導配線となる YBa2Cu3Oxを示
す。EXAMPLE 3 a diagram showing an oxide superconductor wire / oxide insulator interlayer insulating film / oxide superconductor ground plane laminate structure in FIG. 10, YBa 2 1 denotes a substrate, 2 is made of, for example, a ground plane Cu 3 O x superconducting thin film, 9 is, for example, an oxide insulator
PrGaO 3 and 4 represent, for example, YBa 2 Cu 3 O x which becomes a superconducting wiring.
【００１９】超伝導配線に電気信号を流すと、電流に起
因した磁場によって近くの配線に電流が誘起される。こ
のクロストークをなくすためには、磁場が近くの配線に
印加されないように超伝導配線下に超伝導グランドプレ
ーンを設置することが金属系超伝導体を用いた超伝導集
積回路実現時において行われてきた。When an electric signal is passed through the superconducting wire, a magnetic field caused by the current induces a current in the nearby wire. In order to eliminate this crosstalk, it is necessary to install a superconducting ground plane under the superconducting wiring so that a magnetic field is not applied to nearby wiring when implementing a superconducting integrated circuit using a metal-based superconductor. Came.
【００２０】本発明のエッチング材料を用いることによ
って、この構造が酸化物超伝導体薄膜を用いた系におい
ても実現することができたので、これについて説明す
る。すなわち、酸化物超伝導体薄膜２/酸化物絶縁体層
間絶縁膜９/酸化物超伝導体薄膜４の積層構造の試料
を、実施例１の場合と同様に、超伝導配線として残す部
分以外を例えばフォトリソグラフィにより露光、現像
し、本発明のエッチング材料を用いてエッチングを行
う。これにより作製した構造を示したものが図10であ
る。酸化物超伝導体のみをエッチングし、酸化物絶縁体
薄膜をエッチングしない本発明のエッチング材料を用い
ているため、図に示したように、酸化物絶縁体層間絶縁
膜９及びグランドプレーンとなる酸化物超伝導体薄膜４
がエッチングされないで残る。以上によって、酸化物超
伝導体薄膜グランドプレーン上に層間絶縁膜を介して酸
化物超伝導配線を配した構造を実現することができた。By using the etching material of the present invention, this structure could be realized in a system using an oxide superconductor thin film, which will be described below. That is, as in the case of Example 1, the sample of the laminated structure of the oxide superconductor thin film 2 / the oxide insulating interlayer insulating film 9 / the oxide superconductor thin film 4 except the part to be left as the superconducting wiring. For example, exposure and development are performed by photolithography, and etching is performed using the etching material of the present invention. The structure produced by this is shown in FIG. Since the etching material of the present invention that etches only the oxide superconductor and does not etch the oxide insulator thin film is used, as shown in FIG. Superconductor thin film 4
Remains unetched. As described above, the structure in which the oxide superconducting wiring was arranged on the oxide superconductor thin film ground plane via the interlayer insulating film could be realized.
【００２１】なお、上記実施例においては、酸化物絶縁
体膜として PrGaO3を用いた場合の例について説明した
が、PrGaO3以外にも、ペロブスカイト構造を有するSrTi
O3、NdGaO3、LaAlO3、YAlO3等、また、Y2O3、CeO等の単
酸化物も同様に用いることができる。In the above embodiments, an example in which PrGaO 3 is used as the oxide insulator film has been described, but in addition to PrGaO 3 , SrTi having a perovskite structure is also used.
O 3, NdGaO 3, LaAlO 3 , YAlO 3 , etc., also, Y 2 O 3, a single oxide CeO like can be used as well.
【００２２】[0022]
【発明の効果】以上述べてきたように、酸化物絶縁体極
薄膜上の酸化物超伝導体薄膜のエッチング材料及びエッ
チング方法を本発明構成の材料及び方法とすることによ
って、従来技術の有していた課題を解決して、酸化物絶
縁体極薄膜をエッチングすることなく、酸化物超伝導体
薄膜のみをエッチングすることのできるエッチング材料
及びエッチング方法を提供することができた。As described above, by using the etching material and the etching method of the oxide superconductor thin film on the oxide insulator ultrathin film as the material and method of the constitution of the present invention, it is possible to obtain the conventional technology. It was possible to provide an etching material and an etching method capable of etching only an oxide superconductor thin film without etching the oxide insulator ultrathin film by solving the problems.
【図１】基板上に YBa2Cu3Ox薄膜を堆積した状態を示す
断面図。FIG. 1 is a sectional view showing a state where a YBa 2 Cu 3 O x thin film is deposited on a substrate.
【図２】基板上に YBa2Cu3Ox、PrGaO3、YBa2Cu3Ox、レ
ジストを順次堆積した状態を示す断面図。FIG. 2 is a cross-sectional view showing a state where YBa 2 Cu 3 O x , PrGaO 3 , YBa 2 Cu 3 O x , and a resist are sequentially deposited on a substrate.
【図３】図２の試料を希釈酢酸中に16秒間浸漬後の状態
を示す断面図。FIG. 3 is a cross-sectional view showing a state after the sample of FIG. 2 is immersed in diluted acetic acid for 16 seconds.
【図４】図２の試料を希釈硝酸中に２秒間浸漬後の状態
を示す断面図。FIG. 4 is a cross-sectional view showing a state after the sample of FIG. 2 is immersed in diluted nitric acid for 2 seconds.
【図５】基板上に YBa2Cu3Ox、PrGaO3、YBa2Cu3Ox、レ
ジストを順次堆積し、さらにマスクを載せた状態を示す
断面図。FIG. 5 is a cross-sectional view showing a state in which YBa 2 Cu 3 O x , PrGaO 3 , YBa 2 Cu 3 O x , and a resist are sequentially deposited on a substrate, and a mask is placed on the substrate.
【図６】図５の試料を露光し表面固化後現像を行った状
態を示す断面図。FIG. 6 is a cross-sectional view showing a state in which the sample of FIG. 5 is exposed to light and the surface is solidified and then developed.
【図７】図６の試料を希釈酢酸でエッチングした状態を
示す断面図。7 is a cross-sectional view showing a state where the sample of FIG. 6 is etched with diluted acetic acid.
【図８】図７の試料に SiOxを堆積後、リフトオフプロ
セスによってレジスト及びレジスト上に堆積した SiOx
を除去した状態を示す断面図。FIG. 8 is a graph showing the SiO x deposited on the resist of FIG. 7 by a lift-off process after depositing SiO x on the sample.
Sectional drawing which shows the state which removed.
【図９】図８の試料についてリフトオフプロセスにより
上部電極を覆う部分に配線(金)を堆積した状態を示す断
面図。9 is a cross-sectional view showing a state in which wiring (gold) is deposited on a portion covering the upper electrode by a lift-off process for the sample of FIG.
【図１０】酸化物超伝導体配線酸化物絶縁体層間絶縁膜
酸化物超伝導体グランドプレーン積層構造を示す斜視
図。FIG. 10 is a perspective view showing an oxide superconductor wiring oxide insulator interlayer insulating film oxide superconductor ground plane laminated structure.
１…基板、２… YBa2Cu3Ox薄膜、３…酸化物絶縁体極薄
膜、４… YBa2Cu3Ox薄膜、５…レジスト、６…マスク、
７…層間絶縁 SiOx薄膜、８…金配線、９…酸化物絶縁
体層間絶縁膜。1 ... Substrate, 2 ... YBa 2 Cu 3 O x thin film, 3 ... Oxide insulator ultra-thin film, 4 ... YBa 2 Cu 3 O x thin film, 5 ... Resist, 6 ... Mask,
7 ... interlayer insulating SiO x thin film, 8 ... gold wire, 9 ... oxide insulator interlayer insulating film.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 中田 一郎 東京都渋谷区富ケ谷２丁目28番４号 学校 法人 東海大学内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ichiro Nakata 2-28-4, Tomigaya, Shibuya-ku, Tokyo School Tokai University
Claims (2)
膜、酸化物超伝導体薄膜を順次形成してなる積層構造体
の湿式エッチングにおいて、酸化物絶縁膜をエッチング
することなく最上層酸化物超伝導体のみをエッチングす
るエッチング材料がカルボン酸を含有していることを特
徴とする酸化物超伝導体薄膜の選択エッチング材料。1. A wet etching method for a laminated structure comprising an oxide superconductor thin film, an oxide insulating film, and an oxide superconductor thin film sequentially formed on a substrate without etching the oxide insulating film. A selective etching material for an oxide superconductor thin film, wherein the etching material for etching only the upper oxide superconductor contains carboxylic acid.
膜、酸化物超伝導体薄膜を順次形成し、最上層の酸化物
超伝導体薄膜を除去加工する方法において、該最上層酸
化物超伝導体薄膜をカルボン酸を含有するエッチング材
料を用いてエッチングすることを特徴とする酸化物超伝
導体薄膜の選択エッチング方法。2. A method of sequentially forming an oxide superconductor thin film, an oxide insulating film, and an oxide superconductor thin film on a substrate, and removing and processing the uppermost oxide superconductor thin film, wherein the uppermost layer is formed. A method for selectively etching an oxide superconductor thin film, comprising etching the oxide superconductor thin film using an etching material containing a carboxylic acid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5003002A JPH06209126A (en) | 1993-01-12 | 1993-01-12 | Selective etching material and method for oxide superconductor thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5003002A JPH06209126A (en) | 1993-01-12 | 1993-01-12 | Selective etching material and method for oxide superconductor thin film |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06209126A true JPH06209126A (en) | 1994-07-26 |
Family
ID=11545161
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5003002A Pending JPH06209126A (en) | 1993-01-12 | 1993-01-12 | Selective etching material and method for oxide superconductor thin film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06209126A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2020191394A (en) * | 2019-05-23 | 2020-11-26 | 日本電信電話株式会社 | Thin film formation method |
-
1993
- 1993-01-12 JP JP5003002A patent/JPH06209126A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2020191394A (en) * | 2019-05-23 | 2020-11-26 | 日本電信電話株式会社 | Thin film formation method |
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