JPH08139076A - Detection of end point of etching using ellipsometry method - Google Patents
Detection of end point of etching using ellipsometry methodInfo
- Publication number
- JPH08139076A JPH08139076A JP6278914A JP27891494A JPH08139076A JP H08139076 A JPH08139076 A JP H08139076A JP 6278914 A JP6278914 A JP 6278914A JP 27891494 A JP27891494 A JP 27891494A JP H08139076 A JPH08139076 A JP H08139076A
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- Prior art keywords
- film
- etching
- end point
- amount
- light
- Prior art date
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- Superconductor Devices And Manufacturing Methods Thereof (AREA)
- Drying Of Semiconductors (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、酸化物超伝導集積回路
の製造におけるエッチングの終点検出に適用される偏光
解析法によるエッチング終点検出法に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an etching end point by ellipsometry applied to the detection of an etching end point in the manufacture of an oxide superconducting integrated circuit.
【０００２】[0002]
【従来の技術】多層膜を有する酸化物超伝導集積回路の
エッチングプロセスには、一般にイオンビームエッチン
グ法が利用される。イオンビームエッチング法は、試料
を物理的にエッチングするため、材料によるエッチング
速度比を大きくとることができないので、フォトレジス
ト，下地などに対する選択比がとり難く、多層膜でのエ
ッチング終点判定を困難なものにしている。このため、
多層膜に対するエッチング終点の検出は、目視または前
もって求めたエッチングレートから算出した時間で行っ
ていた。このような終点検出法は、エッチング残りやエ
ッチングオーバーが生じやすく、確実なエッチング終点
検出法が必要となっている。2. Description of the Related Art Generally, an ion beam etching method is used for an etching process of an oxide superconducting integrated circuit having a multilayer film. Since the ion beam etching method physically etches the sample, it is difficult to obtain a high etching rate ratio depending on the material. Therefore, it is difficult to obtain a selective ratio with respect to the photoresist, the underlayer, etc., and it is difficult to determine the etching end point in the multilayer film. I am making it. For this reason,
The detection of the etching end point of the multilayer film was performed visually or at a time calculated from an etching rate obtained in advance. Such an end point detection method is liable to cause etching residue or etching over, and thus requires a reliable etching end point detection method.
【０００３】半導体多層膜のエッチングプロセスにおい
ては、以下に示すような偏光解析法を用いた終点検出が
実用化されている。半導体材料に用いられている偏光解
析法には大きく分けて測光法と消光法との二種類があ
る。測光法は、検光子または偏光子を回転させ、エッチ
ング過程において光量変化を解析することにより、試料
表面で反射した光の偏光状態を受光側で測定する。この
方法は、測定パラメータΨとΔとから膜厚を求める方式
で、測定の基本条件としてエッチング過程で光学定数が
変動しないことが要求される。In the process of etching a semiconductor multilayer film, end point detection using an ellipsometry described below has been put to practical use. Ellipsometry used for semiconductor materials is roughly classified into two types, a photometry method and an extinction method. In the photometric method, the polarization state of light reflected on the sample surface is measured on the light receiving side by rotating an analyzer or a polarizer and analyzing a change in light amount during an etching process. This method is a method of obtaining a film thickness from measurement parameters Ψ and Δ, and it is required that the optical constant does not change during the etching process as a basic condition for measurement.
【０００４】一方の消光法は、測定パラメータΨとΔと
には注目せず、受光器に入る光量変化を測定パラメータ
とする。この方法は、例えば表面の薄膜が透明な場合に
は、エッチング終点時に受光器に入る光が消光状態にな
るようにあらかじめ偏光子と検光子との方位角を設定し
ておき、光量変化を追跡する。表面の薄膜が不透明な場
合には、エッチングのはじめに受光器に入る光が消光状
態になるようにあらかじめ偏光子と検光子との方位角を
設定しておいて、光量変化を追跡する。半導体多層膜の
エッチングプロセスにおいては、測光法および消光法い
ずれの方法においても、半導体多層膜の界面において、
明瞭な光量変化が観測されるため、エッチングの終点を
確実に検出することができる。On the other hand, the extinction method does not pay attention to the measurement parameters Ψ and Δ, and uses the change in the amount of light entering the light receiver as the measurement parameter. In this method, for example, when the thin film on the surface is transparent, the azimuth between the polarizer and the analyzer is set in advance so that the light entering the photodetector at the end of etching is in an extinction state, and the change in the light amount is tracked. I do. When the thin film on the surface is opaque, the azimuth angle between the polarizer and the analyzer is set in advance so that the light entering the light receiver at the beginning of the etching is in an extinction state, and the change in the light amount is tracked. In the etching process of the semiconductor multilayer film, in both the photometric method and the quenching method, at the interface of the semiconductor multilayer film,
Since a clear change in the amount of light is observed, the end point of the etching can be reliably detected.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、半導体
デバイスの分野で用いられてきた前述した偏光解析法を
用いた終点検出は、酸化物超伝導材料に対してはそのま
ま適用できないことが、本発明者の実験から明らかとな
った。すなわち、酸化物超伝導材料に対しては、光学定
数が変動するために測光法によるエッチングの終点検出
が行えない。さらに酸化物超伝導材料では、消光状態が
存在しないために消光法によるエッチング終点検出も適
用できない。しかし、本発明者は、半導体材料とは違っ
た酸化物超伝導材料に対する特徴的な偏光解析結果を利
用することで、偏光解析法による終点検出が可能である
ことを見いだした。However, the inventor of the present invention has found that the end point detection using the above-mentioned ellipsometry, which has been used in the field of semiconductor devices, cannot be directly applied to oxide superconducting materials. It became clear from the experiment. That is, with respect to the oxide superconducting material, the end point of the etching cannot be detected by photometry because the optical constant fluctuates. Further, in the case of an oxide superconducting material, since the quenching state does not exist, etching end point detection by the quenching method cannot be applied. However, the present inventor has found that an end point can be detected by an ellipsometry by using a characteristic ellipsometry result for an oxide superconducting material different from a semiconductor material.
【０００６】具体的には、多層膜構造を持つ酸化物超伝
導体集積回路のイオンビームを用いたエッチングプロセ
スにおいて、目視または前もって調べておいたエッチン
グレートによる終点検出では、エッチング時の状況を精
確に捉えることができないため、エッチング残りやエッ
チングオーバーを生じやすく、エッチングプロセスの信
頼性が乏しかった。また、従来、半導体エッチングプロ
セスに用いられていた偏光解析法によるエッチング終点
検出は、そのままでは酸化物超伝導体のエッチングプロ
セスの終点検出には適用できないという問題があった。Specifically, in an etching process using an ion beam of an oxide superconductor integrated circuit having a multilayer film structure, end point detection based on an etching rate visually or in advance has been performed to accurately determine the state of etching. Therefore, etching residue or overetching is likely to occur, and the reliability of the etching process is poor. Further, there has been a problem that the detection of the etching end point by the ellipsometry used in the conventional semiconductor etching process cannot be applied to the detection of the end point of the etching process of the oxide superconductor as it is.
【０００７】したがって本発明は、前述した従来の課題
を解決するためになされたものであり、その目的は、多
層膜を有する酸化物超伝導集積回路の加工において、酸
化物超伝導体に適した偏光解析により、エッチング残り
やエッチングオーバーの生じない終点検出を行えるよう
にした偏光解析法によるエッチング終点検出法を提供す
ることにある。Therefore, the present invention has been made in order to solve the above-mentioned conventional problems, and an object thereof is suitable for an oxide superconductor in processing an oxide superconducting integrated circuit having a multilayer film. An object of the present invention is to provide an etching end point detection method by ellipsometry, which can detect an end point without etching residue or etching over by ellipsometry.
【０００８】[0008]
【課題を解決するための手段】このような目的を達成す
るために本発明による偏光解析法によるエッチング終点
検出法は、エッチング過程において偏光解析装置の受光
強度の変化を追跡して行う方法であり、下層が酸化物超
伝導膜および上層が絶縁膜からなる積層膜のエッチング
プロセスにおいて、偏光解析を行う偏光子，検光子の方
位角を膜法線に対して６５゜〜７５゜の範囲に設定し、
受光量が増加した後、一定値となった時点をエッチング
終点とするようにしたものである。In order to achieve the above object, an etching end point detection method using an ellipsometry according to the present invention is a method for tracking a change in received light intensity of an ellipsometer during an etching process. In the etching process of the laminated film in which the lower layer is composed of the oxide superconducting film and the upper layer is composed of the insulating film, the azimuth of the polarizer and analyzer for performing the polarization analysis is set in the range of 65 to 75 degrees with respect to the film normal. And
After the amount of received light increases, a point in time at which a constant value is reached is set as an etching end point.
【０００９】また、他の発明による偏光解析法によるエ
ッチング終点検出法は、受光量の変化率がピークをとっ
たことを確認してエッチング終点とするようにしたもの
である。また、他の発明による偏光解析法によるエッチ
ング終点検出法は、受光量が減少した後、一定値となっ
た時点をエッチング終点とするようにしたものである。
また、他の発明による偏光解析法によるエッチング終点
検出法は、受光量の変化率が谷をとったことを確認して
エッチング終点とするようにしたものである。Further, in the etching end point detection method by ellipsometry according to another invention, it is confirmed that the rate of change in the amount of received light has reached a peak and the etching end point is determined. In addition, in the etching end point detection method based on the ellipsometry according to another invention, the point in time at which the amount of received light decreases to a constant value is set as the etching end point.
In the etching end point detection method by ellipsometry according to another invention, the etching end point is determined after confirming that the rate of change in the amount of received light has reached a valley.
【００１０】[0010]
【作用】本発明においては、酸化物超伝導体集積回路に
用いられるＹＢ2 Ｃｕ3Ｏ7-x膜およびＳｒＴｉＯ3 膜
は、半導体集積回路で用いられるＳｉおよびＳｉＯ2 の
ような平坦な表面ではなく、その表面には少なくとも数
１０ｎｍ程度の凹凸が存在することが知られている。こ
のように平坦でない表面を持っているために酸化物超伝
導体材料に対して偏光解析を適用すると、エッチングの
進展に伴って表面の凹凸が大きくなったりするために見
かけの光学定数が変化してしまい、精確な膜厚測定がで
きないばかりか、偏光の入射条件をかなり広い範囲で割
り当てても消光状態を得ることができないものと考えら
れる。In the present invention, the YB 2 Cu 3 O 7-x film and the SrTiO 3 film used for the oxide superconductor integrated circuit are formed on a flat surface such as Si and SiO 2 used for the semiconductor integrated circuit. It is known that the surface has irregularities of at least several tens nm. When the ellipsometry is applied to an oxide superconductor material because of its uneven surface, the apparent optical constant changes because the surface irregularities increase with the progress of etching. It is thought that not only cannot accurate film thickness measurement be performed, but also it is not possible to obtain an extinction state even if the incident conditions of polarized light are assigned in a considerably wide range.
【００１１】しかしながら、偏光した入射光を試料に対
して６５゜〜７５゜の範囲に設定することによって試料
表面の凹凸が良好に平均化され、酸化物超伝導系材料よ
り構成される多層構造のエッチング過程において、材料
の違いに応じた受光量変化が見かけ上、生ずるものと考
えられる。したがって、受光量の強度をモニターするこ
とによってエッチングの終点を検出できる。また、受光
量の強度が見かけ上、材料の違いによって異なる値をと
るために受光量の変化率をエッチング深さに対して測定
すれば、界面位置において、受光量強度の変化率はピー
クまたは谷となり、これを用いてもエッチングの終点を
検出できる。However, when the polarized incident light is set in the range of 65 ° to 75 ° with respect to the sample, the unevenness of the sample surface is favorably averaged, and the multilayer structure of the oxide superconducting material is used. In the etching process, it is considered that a change in the amount of received light according to the difference in the material is apparently caused. Therefore, the end point of the etching can be detected by monitoring the intensity of the received light amount. Also, if the change in the received light intensity is measured with respect to the etching depth in order to apparently take a different value depending on the material, the change in the received light intensity will be a peak or a valley at the interface position. The end point of the etching can be detected by using this.
【００１２】[0012]
【実施例】以下、本発明の実施例について図面を用いて
説明する。図１は、本発明による偏光解析法によるエッ
チング終点検出法に用いるイオンビームエッチング装置
の構成を示す概略図である。図１において、イオンビー
ムエッチング装置は、エッチングチャンバー１と、アル
ゴンイオンガン２と、被加工物である試料を支持する試
料ホルダー３と、図示しない真空排気系とから構成さ
れ、エッチングチャンバー１には、イオンビームエッチ
ングを行いながら偏光解析ができるように波長６３２．
８ｎｍのヘリウム・ネオンレーザー光源４と、偏光子５
と、検光子６と、受光器７とから構成される偏光解析装
置が組み込まれている。偏光した入射光を６０°から８
０°の入射角（試料の膜表面の法線からの角度を入射角
と定義する）で被加工物である酸化物超伝導材料の積層
された試料に入射し、この試料から反射された反射光を
検出できるようになっている。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of an ion beam etching apparatus used for an etching end point detection method by ellipsometry according to the present invention. In FIG. 1, the ion beam etching apparatus includes an etching chamber 1, an argon ion gun 2, a sample holder 3 for supporting a sample to be processed, and a vacuum exhaust system (not shown). The wavelength 632.m so that polarization analysis can be performed while performing ion beam etching.
8 nm helium / neon laser light source 4 and polarizer 5
, An ellipsometer 6 and a photodetector 7. Polarized incident light from 60 ° to 8
At an incident angle of 0 ° (the angle from the normal to the film surface of the sample is defined as the angle of incidence), the light is incident on the sample, which is the work piece, on which the oxide superconducting material is laminated, and is reflected from this sample. Light can be detected.
【００１３】（実施例１）まず、被加工物としてＭｇＯ
（００１）基板上に厚さ４００ｎｍのＹＢａ2 Ｃｕ3Ｏ
7-x膜と厚さ２００ｎｍのＳｒＴｉＯ3 膜とを積層して
作製したＹＢＣＯ／ＳｒＴｉＯ3積層膜（以下、ＹＢａ2
Ｃｕ3Ｏ7-xをＹＢＣＯと略記する）を用いた実施例につ
いて説明する。ここで、ＹＢＣＯ／ＳｒＴｉＯ3 積層膜
とは、基板側から順にＹＢＣＯ膜、ＳｒＴｉＯ3 膜が積
層された膜であることを表す。試料への光入射角を６５
゜から８０゜の範囲で変え、それぞれの入射角における
イオンビームエッチング中の受光量を測定した。図２
（ａ），（ｂ），（ｃ），（ｄ），（ｅ）は、ＹＢＣＯ
／ＳｒＴｉＯ3 積層膜の各ビーム入射角６０゜，６５
゜，７０゜，７５゜，８０゜における受光量のエッチン
グ深さ依存性を示したものであり、ＹＢＣＯ膜とＳｒＴ
ｉＯ3 膜との界面を基準点０とし、ＳｒＴｉＯ3 膜の領
域を負の符号で表し、ＹＢＣＯ膜の領域を正の符号で表
してある。(Embodiment 1) First, MgO was used as a workpiece.
400 nm thick YBa 2 Cu 3 O on (001) substrate
A YBCO / SrTiO 3 laminated film (hereinafter referred to as YBa 2) prepared by laminating a 7-x film and a SrTiO 3 film having a thickness of 200 nm.
An example using Cu 3 O 7-x as YBCO) will be described. Here, the YBCO / SrTiO 3 laminated film indicates that the YBCO film and the SrTiO 3 film are laminated in this order from the substrate side. The incident angle of light to the sample is 65
The light reception amount during the ion beam etching at each incident angle was measured while changing the angle from ゜ to 80 °. Figure 2
(A), (b), (c), (d) and (e) are YBCO
/ SrTiO 3 laminated film each beam incident angle 60 °, 65
This graph shows the dependence of the amount of received light on the etching depth at {, 70}, 75 °, and 80 °.
The interface with the iO 3 film is defined as a reference point 0, the region of the SrTiO 3 film is represented by a negative sign, and the region of the YBCO film is represented by a positive sign.
【００１４】図２（ｂ）〜（ｄ）に示すように入射光の
ビーム入射角が６５°〜７５°の範囲においては、ＹＢ
ＣＯ膜およびＳｒＴｉＯ3 膜のそれぞれの領域において
受光量はほぼ一定の値を示すとともにＹＢＣＯ／ＳｒＴ
ｉＯ3 積層膜の界面で大きく変化することから、ＹＢＣ
Ｏ／ＳｒＴｉＯ3 積層膜の界面を特定することができ
る。一方、図２（ａ）および（ｅ）に示すように入射光
のビーム入射角が６０°および８０°の場合は、ＹＢＣ
Ｏ膜またはＳｒＴｉＯ3 膜のそれぞれの領域において受
光量が振動的に変動し、受光量からはＹＢＣＯ／ＳｒＴ
ｉＯ3 積層膜の界面位置を特定することは困難である。
したがって本実施例によるＹＢＣＯ／ＳｒＴｉＯ3 積層
膜においては、図２（ｂ）〜（ｄ）に示すように入射光
のビーム入射角を６５°〜７５°の範囲に設定すること
によって受光量の変化からエッチングの終点検出を行う
ことが可能であり、エッチングの終点の判定は受光量が
減少し、一定になった時点とすればよい。As shown in FIGS. 2B to 2D, when the beam incident angle of incident light is in the range of 65 ° to 75 °, YB
In each of the regions of the CO film and the SrTiO 3 film, the amount of received light shows a substantially constant value, and the YBCO / SrT
YBC has a large change at the interface of the iO 3 laminated film.
The interface of the O / SrTiO 3 laminated film can be specified. On the other hand, when the beam incident angles of the incident light are 60 ° and 80 ° as shown in FIGS.
The amount of received light fluctuates oscillatingly in each region of the O film or the SrTiO 3 film, and the amount of received light indicates YBCO / SrT.
It is difficult to specify the interface position of the iO 3 laminated film.
Therefore, in the YBCO / SrTiO 3 laminated film according to the present embodiment, the amount of received light is changed by setting the beam incident angle of the incident light in the range of 65 ° to 75 ° as shown in FIGS. It is possible to detect the end point of the etching from the above, and the end point of the etching can be determined at the time when the amount of received light becomes constant and becomes constant.
【００１５】（実施例２）前述した実施例１では、受光
量の強度をエッチング深さに対して測定したが、実施例
１と同じ積層構造を持つＹＢＣＯ／ＳｒＴｉＯ3 積層膜
について、試料への光入射角を６５゜から８０゜の範囲
で変え、それぞれの入射角におけるイオンビームエッチ
ング中の受光量の変化率を測定した。図３（ａ），
（ｂ），（ｃ），（ｄ），（ｅ）は、ＹＢＣＯ／ＳｒＴ
ｉＯ3 積層膜の各ビーム入射角６０゜，６５゜，７０
゜，７５゜，８０゜における受光量の変化率のエッチン
グ深さ依存性を示したものであり、ＹＢＣＯ膜とＳｒＴ
ｉＯ3 膜との界面を基準点０とし、ＳｒＴｉＯ3 膜の領
域を負の符号、ＹＢＣＯ膜の領域を正の符号で表してあ
る。(Embodiment 2) In Embodiment 1 described above, the intensity of the amount of received light was measured with respect to the etching depth. However, a YBCO / SrTiO 3 laminated film having the same laminated structure as in Embodiment 1 was applied to a sample. The light incident angle was changed in the range of 65 ° to 80 °, and the rate of change of the amount of light received during ion beam etching at each incident angle was measured. Figure 3 (a),
(B), (c), (d) and (e) are YBCO / SrT
Beam incident angles 60 °, 65 °, 70 of the iO 3 laminated film
The etching depth dependency of the rate of change of the amount of received light at °, 75 °, and 80 ° is shown.
The interface with the iO 3 film is used as a reference point 0, the region of the SrTiO 3 film is represented by a negative sign, and the region of the YBCO film is represented by a positive sign.
【００１６】図３（ｂ）〜（ｄ）に示すようにビーム入
射光の入射角が６５°〜７５°の範囲においては、ＹＢ
ＣＯ膜およびＳｒＴｉＯ3 膜のそれぞれの領域において
受光量変化率はほぼ０に近い値を示すとともに、ＹＢＣ
Ｏ／ＳｒＴｉＯ3 積層膜の界面で急峻なピークを持つこ
とから、ＹＢＣＯ／ＳｒＴｉＯ3 積層膜の界面を特定す
ることができる。一方、図３（ａ）および（ｅ）に示す
ように入射光のビーム入射角が６０°および８０°の場
合は、ＹＢＣＯ膜またはＳｒＴｉＯ3 膜のそれぞれの領
域において受光量の変化率が振動的に変動し、受光量の
変化率からはＹＢＣＯ／ＳｒＴｉＯ3 積層膜の界面位置
を特定することは困難である。したがって本実施例のＹ
ＢＣＯ／ＳｒＴｉＯ3 積層膜においては、図３（ｂ）〜
（ｄ）に示すように入射光の入射角を６５°〜７５°の
範囲に設定することによって受光量の変化からエッチン
グの終点検出を行うことが可能であり、エッチングの終
点の判定は、受光量の変化率が急激に増加し、ピークを
取った時点とすればよい。As shown in FIGS. 3B to 3D, when the incident angle of the beam incident light is in the range of 65 ° to 75 °, YB
In each area of the CO film and the SrTiO 3 film, the rate of change in the amount of received light is close to 0, and the YBC
Since the interface of the O / SrTiO 3 laminated film has a steep peak, the interface of the YBCO / SrTiO 3 laminated film can be specified. On the other hand, as shown in FIGS. 3A and 3E, when the beam incident angles of the incident light are 60 ° and 80 °, the change rate of the received light amount in the respective regions of the YBCO film or the SrTiO 3 film is oscillatory. It is difficult to specify the interface position of the YBCO / SrTiO 3 laminated film from the rate of change of the amount of received light. Therefore, in this embodiment, Y
In the BCO / SrTiO 3 laminated film, FIG.
By setting the incident angle of the incident light in the range of 65 ° to 75 ° as shown in (d), the end point of the etching can be detected from the change in the amount of received light. What is necessary is just to take the time when the rate of change of the amount sharply increases and peaks.
【００１７】（実施例３）被加工物としてＭｇＯ（００
１）基板上に厚さ２００ｎｍのＳｒＴｉＯ3 膜と厚さ５
００ｎｍのＹＢＣＯ膜とを積層して作製したＳｒＴｉＯ
3 ／ＹＢＣＯ積層膜を用いた実施例について説明する。
ここで、ＳｒＴｉＯ3 ／ＹＢＣＯ積層膜とは、基板側か
ら順にＳｒＴｉＯ3 膜、ＹＢＣＯ膜が積層された膜であ
ることを表す。試料への光入射角を６５゜から８０゜の
範囲で変え、それぞれのビーム入射角におけるイオンビ
ームエッチング中の受光量を測定した。図４（ａ），
（ｂ），（ｃ），（ｄ），（ｅ）は、ＳｒＴｉＯ3 ／Ｙ
ＢＣＯ積層膜の各ビーム入射角６０゜，６５゜，７０
゜，７５゜，８０゜における受光量のエッチング深さ依
存性を示したものであり、ＳｒＴｉＯ3 ／ＹＢＣＯ積層
膜の界面を基準点０とし、ＹＢＣＯ膜の領域を負の符
号、ＳｒＴｉＯ3 膜の領域を正の符号で表してある。(Embodiment 3) MgO (00)
1) A 200 nm thick SrTiO 3 film and a thickness of 5 on the substrate
SrTiO fabricated by laminating a 00 nm YBCO film
An embodiment using a 3 / YBCO laminated film will be described.
Here, the SrTiO 3 / YBCO laminated film means a film in which an SrTiO 3 film and a YBCO film are laminated in order from the substrate side. The light incident angle on the sample was changed in the range of 65 ° to 80 °, and the amount of light received during ion beam etching at each beam incident angle was measured. 4 (a),
(B), (c), (d) and (e) are SrTiO 3 / Y
Beam incident angles 60 °, 65 °, 70 of the BCO laminated film
°, 75 °, which shows the etching depth dependence of the amount of light received at 80 °, the SrTiO 3 / YBCO laminated film interface as a reference point 0, the negative areas of the YBCO film code, the SrTiO 3 film The area is represented by a positive sign.
【００１８】図４（ｂ）〜（ｄ）に示すように入射光の
ビーム入射角が６５°〜７５°の範囲においては、Ｓｒ
ＴｉＯ3 膜およびＹＢＣＯ膜のそれぞれの領域において
受光量は、ほぼ一定の値を示すとともに、ＳｒＴｉＯ3
／ＹＢＣＯ積層膜の界面で大きく変化をすることから、
ＳｒＴｉＯ3 ／ＹＢＣＯ積層膜の界面を特定することが
できる。一方、図４（ａ）および（ｅ）に示すように入
射光のビーム入射角が６０°および８０°の場合は、Ｓ
ｒＴｉＯ3 膜またはＹＢＣＯ膜のそれぞれの領域におい
て、受光量が振動的に変動し、受光量からはＳｒＴｉＯ
3 ／ＹＢＣＯ積層膜の界面位置を特定することは困難で
ある。したがって、本実施例のＳｒＴｉＯ3 ／ＹＢＣＯ
積層膜においては、図４（ｂ）〜（ｄ）に示すように入
射光のビーム入射角を６５°〜７５°の範囲に設定する
ことによって受光量の変化からエッチングの終点検出を
行うことが可能であり、エッチングの終点の判定は、受
光量が増加し、一定になった時点とすればよい。As shown in FIGS. 4B to 4D, when the beam incident angle of the incident light is in the range of 65 ° to 75 °, Sr
The light receiving amount in each of the TiO 3 film and the YBCO film shows a substantially constant value, and the SrTiO 3
/ YBCO layer greatly changes at the interface,
The interface of the SrTiO 3 / YBCO laminated film can be specified. On the other hand, when the beam incident angle of the incident light is 60 ° and 80 ° as shown in FIGS.
In each region of the rTiO 3 film or the YBCO film, the amount of received light fluctuates in a vibrating manner.
It is difficult to specify the interface position of the 3 / YBCO laminated film. Therefore, the SrTiO 3 / YBCO of this embodiment
In the laminated film, as shown in FIGS. 4B to 4D, by setting the beam incident angle of the incident light to a range of 65 ° to 75 °, the end point of the etching can be detected from the change in the amount of received light. It is possible, and the end point of the etching may be determined when the amount of received light increases and becomes constant.
【００１９】（実施例４）前述した実施例３では、受光
量をエッチング深さに対し測定したが、実施例３と同じ
積層構造を持つＳｒＴｉＯ3 ／ＹＢＣＯ積層膜につい
て、試料への光入射角を６５゜から８０゜の範囲で変
え、それぞれの入射角におけるイオンビームエッチング
中の受光量の変化率を測定した。図５（ａ），（ｂ），
（ｃ），（ｄ），（ｅ）は、ＳｒＴｉＯ3 ／ＹＢＣＯ積
層膜の各ビーム入射角６０゜，６５゜，７０゜，７５
゜，８０゜における受光量の変化率のエッチング深さ依
存性を示したものであり、ＳｒＴｉＯ3 膜とＹＢＣＯ膜
との界面を基準点０とし、ＹＢＣＯ膜の領域を負の符
号、ＳｒＴｉＯ3 膜の領域を正の符号で表してある。(Embodiment 4) In the above-described embodiment 3, the amount of received light was measured with respect to the etching depth. However, for the SrTiO 3 / YBCO laminated film having the same laminated structure as in the embodiment 3, the light incident angle on the sample was measured. Was changed in the range of 65 ° to 80 °, and the change rate of the amount of received light during the ion beam etching at each incident angle was measured. 5 (a), (b),
(C), (d), and (e) are the incident angles of each beam of the SrTiO 3 / YBCO laminated film 60 °, 65 °, 70 °, 75.
This figure shows the etching depth dependency of the rate of change in the amount of received light at 80 ° and 80 °, where the interface between the SrTiO 3 film and the YBCO film is the reference point 0, and the YBCO film region has a negative sign, and the SrTiO 3 film has a negative sign. Area is represented by a positive sign.
【００２０】図５（ｂ）〜（ｄ）に示すように入射光の
ビーム入射角が６５°〜７５°の範囲においては、Ｓｒ
ＴｉＯ3 膜およびＹＢＣＯ膜のそれぞれの領域において
受光量の変化率はほぼ０に近い値を示すとともに、Ｓｒ
ＴｉＯ3 ／ＹＢＣＯ積層膜の界面で深い谷を持つことか
ら、ＳｒＴｉＯ3 ／ＹＢＣＯ積層膜の界面を特定するこ
とができる。一方、図５（ａ）および（ｅ）に示すよう
に入射光のビーム入射角が６０°および８０°の場合
は、ＳｒＴｉＯ3 膜またはＹＢＣＯ膜のそれぞれの領域
において、受光量の変化率が振動的に変動し、受光量の
変化率からはＳｒＴｉＯ3 ／ＹＢＣＯ積層膜の界面位置
を特定することは困難である。したがって本実施例のＳ
ｒＴｉＯ3 ／ＹＢＣＯ積層膜においては、図５（ｂ）〜
（ｄ）に示すように入射光のビーム入射角を６５°〜７
５°の範囲に設定することによって受光量の変化からエ
ッチングの終点検出を行うことが可能であり、エッチン
グの終点の判定は、受光量の変化率が急激に減少し、谷
になった時点とすればよい。As shown in FIGS. 5B to 5D, when the beam incident angle of the incident light is in the range of 65 ° to 75 °, Sr
In each region of the TiO 3 film and the YBCO film, the rate of change in the amount of received light is close to 0, and the Sr
Since there is a deep valley at the interface of the TiO 3 / YBCO laminated film, the interface of the SrTiO 3 / YBCO laminated film can be specified. On the other hand, if the beam incidence angle of the incident light as shown in FIG. 5 (a) and (e) is 60 ° and 80 °, in each area of the SrTiO 3 film or YBCO film, the light-receiving rate of change vibration It is difficult to specify the interface position of the SrTiO 3 / YBCO laminated film from the rate of change in the amount of received light. Therefore, S in the present embodiment
In the case of the rTiO 3 / YBCO laminated film, FIG.
As shown in (d), the beam incident angle of the incident light is 65 ° to 7 °.
It is possible to detect the end point of the etching from the change in the amount of received light by setting the range to 5 °. do it.
【００２１】（実施例５）なお、前述した実施例１〜実
施例４においては、絶縁膜としてＳｒＴｉＯ3 膜と、酸
化物超伝導膜としてＹＢＣＯ膜とからなる多層膜のイオ
ンビームエッチング過程の偏光解析について説明した
が、絶縁膜がＬａＡｌＯ3 膜またはＭｇＯ膜からなり、
酸化物超伝導膜がＢｉ2Ｓｒ2ＣａＣｕ2Ｏx（以下ＢＳＣ
ＣＯと略記する）膜からなる多層膜においても、図２〜
図５の場合とほぼ同等の結果が得られた。すなわち、下
層膜が酸化物超伝導体膜で上層膜が絶縁体膜からなる多
層膜（ＹＢＣＯ／ＬａＡｌＯ3 ，ＹＢＣＯ／ＭｇＯ，Ｂ
ＳＣＣＯ／ＳｒＴｉＯ3 ，ＢＳＣＣＯ／ＬａＡｌＯ3 ，
ＢＳＣＣＯ／ＭｇＯ）においては、入射光のビーム入射
角が６５°〜７５°の範囲に設定すれば、酸化物超伝導
体膜および絶縁体膜のそれぞれの領域において受光量
は、ほぼ一定の値を示すとともに、酸化物超伝導体膜／
絶縁体膜の界面で大きく変化することから、超伝導体膜
／絶縁体膜の界面を特定することができる。(Embodiment 5) In the above-mentioned Embodiments 1 to 4, the polarization in the ion beam etching process of the multilayer film composed of the SrTiO 3 film as the insulating film and the YBCO film as the oxide superconducting film was used. The analysis was explained, but the insulating film is made of LaAlO 3 film or MgO film,
The oxide superconducting film is made of Bi 2 Sr 2 CaCu 2 O x (hereinafter referred to as BSC
2 to a multilayer film composed of a film (abbreviated as CO).
Almost the same results as in FIG. 5 were obtained. That is, a multilayer film (YBCO / LaAlO 3 , YBCO / MgO, B) in which the lower film is an oxide superconductor film and the upper film is an insulator film
SCCO / SrTiO 3 , BSCCO / LaAlO 3 ,
In BSCCO / MgO), if the beam incident angle of the incident light is set in the range of 65 ° to 75 °, the light reception amount in each region of the oxide superconductor film and the insulator film has a substantially constant value. And the oxide superconductor film /
Since it greatly changes at the interface of the insulator film, the interface between the superconductor film and the insulator film can be specified.
【００２２】また、入射光のビーム入射角が６５°〜７
５°の範囲においては、酸化物超伝導体膜および絶縁体
膜のそれぞれの領域において受光量の変化率は、ほぼ０
に近い値を示すとともに、酸化物超伝導体膜／絶縁体膜
の界面で急峻なピークを持つことから、酸化物超伝導体
膜／絶縁体膜の界面を特定することができる。受光量ま
たは受光量の変化率からエッチングの終点検出ができ
る。酸化物超伝導体膜／絶縁体膜の多層構造の場合、エ
ッチングの終点の判定は、受光量が減少し、一定になっ
た時点または受光量の変化率が急激に増加し、ピークを
取った時点とすればよい。The beam incident angle of the incident light is 65 ° to 7 °.
In the range of 5 °, the rate of change in the amount of received light in each region of the oxide superconductor film and the insulator film is almost zero.
And a sharp peak at the interface between the oxide superconductor film and the insulator film, so that the interface between the oxide superconductor film and the insulator film can be specified. The end point of etching can be detected from the received light amount or the change rate of the received light amount. In the case of the multilayer structure of the oxide superconductor film / insulator film, the end point of the etching was judged to have a peak when the amount of received light decreased and became constant or the rate of change in the amount of received light increased sharply. It may be a point in time.
【００２３】一方、下層膜が絶縁体膜で上層膜が酸化物
超伝導体膜からなる多層膜（ＬａＡｌＯ3 ／ＹＢＣＯ，
ＭｇＯ／ＹＢＣＯ，ＳｒＴｉＯ3 ／ＢＳＣＣＯ，ＬａＡ
ｌＯ3 ／ＢＳＣＣＯ，ＭｇＯ／ＢＳＣＣＯ）において
は、入射光のビーム入射角が６５°〜７５°の範囲に設
定すれば、絶縁体膜および酸化物超伝導体膜のそれぞれ
の領域において受光量は、ほぼ一定の値を示すととも
に、絶縁体膜／酸化物超伝導体膜の界面で大きく変化す
ることから、絶縁体膜／酸化物超伝導体膜の界面を特定
することができる。また、入射光のビーム入射角が６５
°〜７５°の範囲においては、絶縁体膜および酸化物超
伝導体膜のそれぞれの領域において受光量の変化率はほ
ぼ０に近い値を示すとともに、酸化物超伝導体膜／絶縁
体膜の界面で急峻なピークを持つことから、酸化物超伝
導体膜／絶縁体膜の界面を特定することができる。受光
量または受光量の変化率からエッチングの終点検出がで
きる。絶縁体膜／酸化物超伝導体膜の多層構造の場合、
エッチングの終点の判定は、受光量が増加し一定になっ
た時点または受光量の変化率が急激に減少し、谷になっ
た時点とすればよい。On the other hand, a multilayer film (LaAlO 3 / YBCO, laminar) in which the lower film is an insulator film and the upper film is an oxide superconductor film.
MgO / YBCO, SrTiO 3 / BSCCO, LaA
In the case of (IO 3 / BSCCO, MgO / BSCCO), if the beam incident angle of the incident light is set in the range of 65 ° to 75 °, the amount of received light in each region of the insulator film and the oxide superconductor film becomes Since it shows a substantially constant value and changes greatly at the interface between the insulator film and the oxide superconductor film, the interface between the insulator film and the oxide superconductor film can be specified. The beam incident angle of the incident light is 65
In the range of ° to 75 °, the rate of change of the amount of received light in each region of the insulator film and the oxide superconductor film shows a value close to 0, and the ratio of the oxide superconductor film / insulator film Since the interface has a steep peak, the interface between the oxide superconductor film and the insulator film can be specified. The end point of etching can be detected from the received light amount or the change rate of the received light amount. In the case of a multilayer structure of an insulator film / oxide superconductor film,
The end point of the etching may be determined when the amount of received light increases and becomes constant or when the rate of change in the amount of received light rapidly decreases and reaches a valley.
【００２４】[0024]
【発明の効果】以上、説明したように本発明によれば、
酸化物超伝導集積回路プロセスにおいて、従来困難であ
ったエッチング終点検出を容易に行うことができるの
で、プロセスの信頼性を大幅に向上させることができる
という極めて優れた効果が得られる。As described above, according to the present invention,
In the oxide superconducting integrated circuit process, the etching end point, which has been difficult in the past, can be easily detected, so that an extremely excellent effect that the reliability of the process can be greatly improved can be obtained.
【図１】 本発明による偏光解析法によるエッチング終
点検出法を説明するための偏光解析装置を組み込んだイ
オンビームエッチング装置の構成を示す概略図である。FIG. 1 is a schematic diagram showing a configuration of an ion beam etching apparatus incorporating a polarization analyzer for explaining an etching end point detection method by a polarization analyzer according to the present invention.
【図２】 ＭｇＯ基板上に作製したＹＢＣＯ膜／ＳｒＴ
ｉＯ3 膜のイオンビームエッチングにおける受光量のエ
ッチング深さ依存性を示す図である。FIG. 2 YBCO film / SrT fabricated on MgO substrate
FIG. 9 is a diagram showing the dependence of the amount of light received on the etching depth in the ion beam etching of the iO 3 film.
【図３】 ＭｇＯ基板上に作製したＹＢＣＯ膜／ＳｒＴ
ｉＯ3 膜のイオンビームエッチングにおける受光量変化
率のエッチング深さ依存性を示す図である。FIG. 3 YBCO film / SrT fabricated on MgO substrate
FIG. 9 is a diagram showing the dependence of the rate of change of the amount of received light on the etching depth in the ion beam etching of the iO 3 film.
【図４】 ＭｇＯ基板上に作製したＳｒＴｉＯ3 膜／Ｙ
ＢＣＯ膜のイオンビームエッチングにおける受光量のエ
ッチング深さ依存性を示す図である。FIG. 4 SrTiO 3 film / Y formed on MgO substrate
It is a figure which shows the etching depth dependence of the light-receiving amount in ion beam etching of a BCO film.
【図５】 ＭｇＯ基板基板上に作製したＳｒＴｉＯ3 膜
／ＹＢＣＯ膜のイオンビームエッチングにおける受光量
変化率のエッチング深さ依存性を示す図である。FIG. 5 is a diagram showing the etching depth dependence of the rate of change in the amount of received light in ion beam etching of a SrTiO 3 film / YBCO film formed on a MgO substrate.
１…エッチングチャンバー、２…アルゴンイオンガン、
３…試料ホルダー、４…ヘリウム・ネオンレーザー光
源、５…偏光子、６…検光子、７…受光器。1. Etching chamber, 2. Argon ion gun,
3 ... sample holder, 4 ... helium / neon laser light source, 5 ... polarizer, 6 ... analyzer, 7 ... light receiver.
Claims (4)
膜からなる積層膜のエッチングプロセスにおいて、偏光
解析を行う偏光子，検光子の方位角を膜法線に対して６
５度〜７５度の範囲に設定し、受光量が増大した後、一
定になった時点をエッチング終点とすることを特徴とし
た偏光解析法によるエッチング終点検出法。1. An azimuthal angle of a polarizer and an analyzer for performing polarization analysis in an etching process of a laminated film in which a lower layer is an oxide superconducting film and an upper layer is an insulating film.
An etching end point detection method by ellipsometry, characterized in that the etching end point is set to be within a range of 5 degrees to 75 degrees, and after the amount of received light is increased, the point becomes constant.
膜からなる積層膜のエッチングプロセスにおいて、偏光
解析を行う偏光子，検光子の方位角を膜法線に対して６
５度〜７５度の範囲に設定し、受光量の変化率がピーク
をとったことを確認してエッチング終点とすることを特
徴とした偏光解析法によるエッチング終点検出法。2. An azimuth angle of a polarizer and an analyzer for polarization analysis is 6 relative to a film normal in an etching process of a laminated film having a lower layer made of an oxide superconducting film and an upper layer made of an insulating film.
An etching end point detection method by ellipsometry, which is set in the range of 5 degrees to 75 degrees, and is confirmed as the etching end point after confirming that the rate of change in the amount of received light has reached a peak.
膜からなる積層膜のエッチングプロセスにおいて、偏光
解析を行う偏光子，検光子の方位角を膜法線に対して６
５度〜７５度の範囲に設定し、受光量が減少した後、一
定になった時点をエッチング終点とすることを特徴とし
た偏光解析法によるエッチング終点検出法。3. An azimuthal angle of a polarizer and an analyzer for performing polarization analysis in an etching process of a laminated film in which a lower layer is an insulating film and an upper layer is an oxide superconducting film is 6 degrees with respect to a film normal.
An etching end point detection method by ellipsometry, wherein the etching end point is set in a range of 5 degrees to 75 degrees and a point in time when the amount of received light decreases and becomes constant becomes an etching end point.
膜からなる積層膜のエッチングプロセスにおいて、偏光
解析を行う偏光子，検光子の方位角を膜法線に対して６
５度〜７５度の範囲に設定し、受光量の変化率が谷にな
ったことを確認してエッチング終点とすることを特徴と
した偏光解析法によるエッチング終点検出法。4. An azimuth angle of a polarizer and an analyzer for polarization analysis is 6 with respect to a film normal in an etching process of a laminated film having a lower layer made of an insulating film and an upper layer made of an oxide superconducting film.
An etching end point detection method based on ellipsometry, which is set in the range of 5 degrees to 75 degrees, and confirms that the rate of change in the amount of received light has reached a valley and sets the etching end point.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6278914A JP2601227B2 (en) | 1994-11-14 | 1994-11-14 | Ellipsometric end point detection method by ellipsometry |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6278914A JP2601227B2 (en) | 1994-11-14 | 1994-11-14 | Ellipsometric end point detection method by ellipsometry |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08139076A true JPH08139076A (en) | 1996-05-31 |
| JP2601227B2 JP2601227B2 (en) | 1997-04-16 |
Family
ID=17603853
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6278914A Expired - Lifetime JP2601227B2 (en) | 1994-11-14 | 1994-11-14 | Ellipsometric end point detection method by ellipsometry |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2601227B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2805924A1 (en) * | 2000-03-06 | 2001-09-07 | France Telecom | Polycrystalline silicon layer etching process used in production of emitter self-aligned with extrinsic base of bipolar transistor involves stopping plasma-etching on or in germanium or silicon-germanium intermediate layer, to form grooves |
| WO2020028105A1 (en) * | 2018-07-31 | 2020-02-06 | Tokyo Electron Limited | Normal-incidence in-situ process monitor sensor |
-
1994
- 1994-11-14 JP JP6278914A patent/JP2601227B2/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2805924A1 (en) * | 2000-03-06 | 2001-09-07 | France Telecom | Polycrystalline silicon layer etching process used in production of emitter self-aligned with extrinsic base of bipolar transistor involves stopping plasma-etching on or in germanium or silicon-germanium intermediate layer, to form grooves |
| WO2020028105A1 (en) * | 2018-07-31 | 2020-02-06 | Tokyo Electron Limited | Normal-incidence in-situ process monitor sensor |
| US10978278B2 (en) | 2018-07-31 | 2021-04-13 | Tokyo Electron Limited | Normal-incident in-situ process monitor sensor |
| US11961721B2 (en) | 2018-07-31 | 2024-04-16 | Tokyo Electron Limited | Normal-incidence in-situ process monitor sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2601227B2 (en) | 1997-04-16 |
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