JPH0251267B2 - - Google Patents
Info
- Publication number
- JPH0251267B2 JPH0251267B2 JP60108288A JP10828885A JPH0251267B2 JP H0251267 B2 JPH0251267 B2 JP H0251267B2 JP 60108288 A JP60108288 A JP 60108288A JP 10828885 A JP10828885 A JP 10828885A JP H0251267 B2 JPH0251267 B2 JP H0251267B2
- Authority
- JP
- Japan
- Prior art keywords
- film
- superconducting
- resistance
- nitride
- resistive film
- 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 - Lifetime
Links
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 28
- 229910052757 nitrogen Inorganic materials 0.000 claims description 14
- 229910052721 tungsten Inorganic materials 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 2
- 239000010937 tungsten Substances 0.000 claims 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical group [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims 1
- -1 tungsten nitride Chemical class 0.000 claims 1
- 238000000034 method Methods 0.000 description 25
- 150000004767 nitrides Chemical class 0.000 description 13
- 238000004519 manufacturing process Methods 0.000 description 8
- 229910052758 niobium Inorganic materials 0.000 description 6
- 229910045601 alloy Inorganic materials 0.000 description 5
- 239000000956 alloy Substances 0.000 description 5
- 238000001312 dry etching Methods 0.000 description 5
- 238000004544 sputter deposition Methods 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 4
- 238000005137 deposition process Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 239000002344 surface layer Substances 0.000 description 4
- 238000009826 distribution Methods 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 238000001020 plasma etching Methods 0.000 description 3
- 229910000978 Pb alloy Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000001307 helium Substances 0.000 description 2
- 229910052734 helium Inorganic materials 0.000 description 2
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000007261 regionalization Effects 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 239000013077 target material Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N60/00—Superconducting devices
- H10N60/10—Junction-based devices
Landscapes
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は液体ヘリウム温度（4.2K）において
動作させる超電導回路用抵抗素子に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a resistance element for a superconducting circuit operated at liquid helium temperature (4.2 K).
従来の超電導スイツチング回路用抵抗膜として
は米国特許第3913120号に記載のようにAuIn2合
金が用いられて来た。AuIn2合金はPb合金を主体
とする超電導回路あるいは製造工程において使用
され、リフトオフ工程に最も適した抵抗膜材料で
あつた。しかるに、Pb合金を主体とする超電導
回路よりさらに耐久性と信頼性に優れるNbある
いはNb化合物系超電導回路の製造工程はドライ
エツチングを主体とする工程が用いられる。この
ようなドライエツチング工程に対してAuIn2合金
は適応性が無い。さらにAuIn2合金は100℃前後
に加熱されることにより、抵抗値の変化を来たす
という特性を有していた。そこで、ドライエツチ
ング工程に対応できるとともに、抵抗値の経時変
化や、加熱処理による特性変化が無く、かつNb
あるいはNb化合物系超電導回路に適合する抵抗
膜材料として、MoあるいはTa膜などが考えられ
た。しかしながら、Moは表面層における腐食の
問題が、Taはベータ相の結晶構造が形成され望
ましいシート抵抗値（0.5〜10Ω／口）を得るの
が困難であるという問題があつた。
As a conventional resistive film for a superconducting switching circuit, an AuIn 2 alloy has been used as described in US Pat. No. 3,913,120. AuIn 2 alloy is used in superconducting circuits and manufacturing processes that mainly consist of Pb alloys, and was the most suitable resistive film material for the lift-off process. However, the manufacturing process of Nb or Nb compound-based superconducting circuits, which are more durable and reliable than superconducting circuits based on Pb alloys, uses a process that mainly uses dry etching. AuIn 2 alloy is not suitable for such a dry etching process. Furthermore, the AuIn 2 alloy had the property of causing a change in resistance value when heated to around 100°C. Therefore, it is compatible with the dry etching process, there is no change in resistance value over time, there is no change in characteristics due to heat treatment, and Nb
Alternatively, Mo or Ta films were considered as resistive film materials suitable for Nb compound-based superconducting circuits. However, Mo has a problem of corrosion in the surface layer, and Ta has a problem that a beta phase crystal structure is formed, making it difficult to obtain a desired sheet resistance value (0.5 to 10 Ω/hole).
本発明の目的は、ドライエツチング工程に対応
できるとともに、抵抗値の経時変化や加熱処理に
よる特性変化がなく、かつNbあるいはNb化合物
系超電導回路に適合し、しかも表面層が化学的に
安定であり、0.5〜10Ω／口の範囲でシート抵抗
を調節し得る抵抗膜材料を提供することにある。
The object of the present invention is to be compatible with a dry etching process, to have no change in resistance value over time or to change in characteristics due to heat treatment, to be compatible with Nb or Nb compound-based superconducting circuits, and to have a chemically stable surface layer. The object of the present invention is to provide a resistive film material whose sheet resistance can be adjusted in the range of 0.5 to 10 Ω/hole.
本発明においてはNbあるいはNb化合物系超電
導回路に適合し、表面層が化学的に安定であり、
高い再現性と均一性をもつて作製し得る抵抗膜材
料としてＷ、あるいは40at.％までの窒素を含有
する窒化Ｗを用いる。必要とするシート抵抗値に
応じて、上記組成の範囲内で窒素の濃度を可変と
する。
The present invention is compatible with Nb or Nb compound-based superconducting circuits, and has a chemically stable surface layer.
W or W nitride containing up to 40 at.% nitrogen is used as a resistive film material that can be manufactured with high reproducibility and uniformity. The nitrogen concentration can be varied within the above composition range depending on the required sheet resistance value.
本発明を以下の実施例にもとづいて説明する。
本実施例においては、つぎに述べる方法により超
電導回路用抵抗膜の作製を行つた。スパツタ装置
中にSiOを200nｍ堆積したSiウエハを装着した。
ターゲツト材はＷとした。スパツタは直流マグネ
トロンスパツタ方式を採用した。ターゲツトの寸
法は12.5cm×25cmであり、ターゲツトが上向き
で、Siウエハが下向きになるように配置した。こ
の状態でスパツタ装置を真空度10-4Paまで排気
し、しかる後に、Arを1Pa導入した。Arによる
直流放電を行い、ターゲツトに対して2W／cm2の
電力を印加した。この条件におけるスパツタによ
りSiウエハ上に1nｍ／ｓの堆積速度でＷ膜を付着
した。Ｗ膜の膜厚は100nｍとした。窒素を含む
Ｗ膜の場合は、スパツタ装置内に窒素を、膜中の
窒素濃度に対応した割合で導入し、Arと窒素の
混合ガス雰囲気中においてＷのスパツタを行い、
Siウエハ上に窒化Ｗを堆積した。
The present invention will be explained based on the following examples.
In this example, a resistive film for a superconducting circuit was manufactured by the method described below. A Si wafer with 200 nm of SiO deposited was placed in a sputtering device.
The target material was W. The sputter uses a DC magnetron sputter method. The dimensions of the target were 12.5 cm x 25 cm, and it was arranged so that the target faced upward and the Si wafer faced downward. In this state, the sputtering device was evacuated to a vacuum level of 10 -4 Pa, and then Ar was introduced at 1 Pa. DC discharge was performed using Ar, and a power of 2 W/cm 2 was applied to the target. A W film was deposited on the Si wafer at a deposition rate of 1 nm/s by sputtering under these conditions. The thickness of the W film was 100 nm. In the case of a W film containing nitrogen, nitrogen is introduced into the sputtering device at a rate corresponding to the nitrogen concentration in the film, and W is sputtered in a mixed gas atmosphere of Ar and nitrogen.
W nitride was deposited on a Si wafer.
以上の方法によりウエハ全面にＷ膜、あるいは
窒化Ｗ膜を形成した。しかる後に、抵抗膜用レジ
ストパターンを形成した。レジストパターン形成
後、ウエハをプラズマエツチング装置に装着し、
SF6と窒素の混合ガス中においてＷあるいは窒化
Ｗのエツチングを行つた。ガス中における窒素濃
度は５％とした。ガス圧は10Pa、入射パワー密
度は0.4W／cm2とした。この条件下において、膜
厚100nｍのＷあるいは窒化Ｗのエツチングは１
分以内で終了した。本パターン形成工程によつ
て、４端子法による膜の電気抵抗を測定するため
の抵抗膜パターンを完成した。 A W film or a W nitride film was formed on the entire surface of the wafer by the method described above. After that, a resist pattern for a resistive film was formed. After forming the resist pattern, the wafer is mounted on a plasma etching device,
Etching of W or W nitride was performed in a mixed gas of SF 6 and nitrogen. The nitrogen concentration in the gas was 5%. The gas pressure was 10 Pa, and the incident power density was 0.4 W/cm 2 . Under these conditions, etching of W or W nitride with a thickness of 100 nm is 1
Finished within minutes. Through this pattern forming process, a resistive film pattern for measuring the electrical resistance of the film by the four-terminal method was completed.
尚、超電導回路に用いる抵抗膜の形成工程とし
ては、抵抗の長さを規定するための絶縁膜用リフ
トオフレジストパターン形成工程、SiO絶縁膜堆
積工程、およびリフトオフ工程、さらに超電導配
線用Nb膜堆積工程、超電導配線膜用レジストパ
ターン形成工程およびNb膜のエツチング工程を
含む。 The formation process of the resistive film used in the superconducting circuit includes a lift-off resist pattern formation process for an insulating film to define the length of the resistor, a SiO insulating film deposition process, a lift-off process, and an Nb film deposition process for superconducting wiring. , including a step of forming a resist pattern for a superconducting wiring film and a step of etching a Nb film.
以上の製造工程により作製したＷあるいは窒化
Ｗ膜は、その特性が安定であり、絶縁膜を被覆し
た状態においては200℃における加熱処理に対し
て、１％の精度で抵抗値の変化をきたさなかつ
た。さらに幅5μｍを有する抵抗膜の抵抗値の均
一性に関しては、抵抗率の抵抗素子間分布は±２
％以内であり、また抵抗値の抵抗素子間分布の主
要な要因は寸法の不均一性によるものであつた。 The W or nitride W film produced by the above manufacturing process has stable characteristics, and when coated with an insulating film, the resistance value does not change with an accuracy of 1% even after heat treatment at 200°C. Ta. Furthermore, regarding the uniformity of the resistance value of a resistive film with a width of 5 μm, the distribution of resistivity between resistive elements is ±2
%, and the main factor in the distribution of resistance values among resistive elements was due to non-uniformity of dimensions.
抵抗値の調節に関して、窒化Ｗの抵抗率の窒化
Ｗ中における窒素濃度依存性を第１図に示した。
第１図に示すごとく、窒化Ｗの抵抗率は10-7Ω／
ｍから２×10-6Ω／ｍまで変化した。つまり膜厚
100nｍのシート抵抗値として１Ωから20Ωまで
の値が得られた。なお、シート抵抗が大き過ぎる
場合、発熱によつて抵抗膜および周辺回路の温度
上昇をもたらす。この点からシート抵抗は10Ω以
下が望ましく、窒化Ｗ中の窒素濃度としては
40at.％以下となる。この領域における抵抗を示
す窒化Ｗ膜はすべて200℃における加熱処理に対
して、１％の精度で抵抗値の変化をきたさなかつ
た。 Regarding the adjustment of the resistance value, FIG. 1 shows the dependence of the resistivity of nitrided W on the nitrogen concentration in nitrided W.
As shown in Figure 1, the resistivity of W nitride is 10 -7 Ω/
m to 2×10 -6 Ω/m. In other words, the film thickness
Sheet resistance values at 100 nm ranged from 1Ω to 20Ω. Note that if the sheet resistance is too large, heat generation will cause the temperature of the resistive film and peripheral circuits to rise. From this point of view, it is desirable that the sheet resistance is 10Ω or less, and the nitrogen concentration in W nitride is
40at.% or less. All of the W nitride films exhibiting resistance in this region showed no change in resistance value with an accuracy of 1% when subjected to heat treatment at 200°C.
つぎに、超電導回路中における抵抗体としての
性能を確認するために、前述のごとき作製工程を
通じて超電導回路の作製を行つた。すなわち、こ
れらはSiウエハ上における窒化Ｗ膜のスパツタに
よる形成工程、レジストパターンの形成およびプ
ラズマエツチングによるパターン形成工程、絶縁
膜用リフトオフレジストパターン形成工程、SiO
絶縁膜堆積工程、およびリフトオフ工程、さらに
超電導配線用Nb膜堆積工程、超電導配線用レジ
ストパターン形成工程およびNb膜のプラズマエ
ツチングによるパターン形成工程、さらには超電
導素子用の膜形成およびパターン形成工程を含
む。超電導素子用の膜としてはNb、NbNおよび
PbIn合金等の超電導膜、SiO絶縁膜等を用いる。
これら回路作製工程を通じた後、抵抗膜の抵抗特
性を測定した。この結果によれば、超電導回路作
製工程を通じた後の抵抗膜の抵抗特性と抵抗膜の
みの作製工程を通じた後の抵抗特性との間に全く
差異を認められなかつた。このことは窒化Ｗ膜の
表面層が超電導回路作製中におけるパターン形成
工程等によつて汚染等による劣化の影響を受けな
いことを意味する。 Next, in order to confirm the performance as a resistor in a superconducting circuit, a superconducting circuit was fabricated through the fabrication process described above. In other words, these include a process for forming a W nitride film on a Si wafer by sputtering, a process for forming a resist pattern and a pattern using plasma etching, a process for forming a lift-off resist pattern for an insulating film, and a process for forming a lift-off resist pattern on an SiO wafer.
Including an insulating film deposition process, a lift-off process, a Nb film deposition process for superconducting wiring, a resist pattern forming process for superconducting wiring, a pattern forming process by plasma etching of the Nb film, and a film forming and pattern forming process for superconducting elements. . Nb, NbN and
Superconducting films such as PbIn alloys, SiO insulating films, etc. are used.
After going through these circuit fabrication steps, the resistance characteristics of the resistive film were measured. According to the results, no difference was observed between the resistance characteristics of the resistive film after passing through the superconducting circuit manufacturing process and the resistance characteristics after passing through the process of manufacturing only the resistive film. This means that the surface layer of the W nitride film is not affected by deterioration due to contamination or the like during the pattern forming process during the fabrication of the superconducting circuit.
抵抗膜として重要なパラメータの１つである配
線電極膜との接触抵抗に関しては、Nb配線膜を
形成する前の工程として、抵抗膜を含むウエハ表
面全面をArの高周波プラズマ中に晒した場合、
接触抵抗は零であつた。 Regarding the contact resistance with the wiring electrode film, which is one of the important parameters for a resistive film, when the entire surface of the wafer including the resistive film is exposed to high-frequency Ar plasma as a step before forming the Nb wiring film,
Contact resistance was zero.
なお、窒化Ｗ膜の膜厚再現性は±3nｍであつ
たので、膜厚0.05μｍ以下の抵抗膜の場合、抵抗
値再現性に問題を生じる。通常配線用Nb膜等の
膜厚は通常0.2〜1.0μｍとしているので、抵抗膜
端部における配線膜の被覆性の問題等から、抵抗
膜の膜厚上限は1.0μｍである。 Note that since the film thickness reproducibility of the W nitride film was ±3 nm, a problem arises in resistance value reproducibility in the case of a resistive film with a film thickness of 0.05 μm or less. Since the thickness of the Nb film for wiring is usually 0.2 to 1.0 μm, the upper limit of the thickness of the resistive film is 1.0 μm due to problems such as coverage of the wiring film at the ends of the resistive film.
本発明によれば、超電導スイツチング回路用抵
抗膜として、Ｗ、あるいは40％以内の窒素を含む
Ｗを用いることにより、以下のごとき効果を有す
る。
According to the present invention, by using W or W containing up to 40% nitrogen as a resistive film for a superconducting switching circuit, the following effects can be obtained.
(1) ドライエツチングを主体とする超電導スイツ
チング回路形成工程に適応できる。(1) It can be applied to superconducting switching circuit formation processes that mainly involve dry etching.
(2) 膜中の窒素濃度を選ぶことにより、0.5Ωか
ら10Ωまでの任意のシート抵抗を得られる。(2) By selecting the nitrogen concentration in the film, any sheet resistance from 0.5Ω to 10Ω can be obtained.
(3) 抵抗値の一様性に関して、抵抗率の不均一性
に起因する抵抗値の分布は２％以内である。(3) Regarding the uniformity of resistance values, the distribution of resistance values due to non-uniformity of resistivity is within 2%.
(4) 200℃までの加熱、あるいは室温と動作温度
である液体ヘリウム温度間における温度サイク
ルに対して、抵抗値の変化は皆無である。(4) There is no change in resistance when heated up to 200°C or temperature cycled between room temperature and the operating temperature of liquid helium.
第１図は窒化Ｗ膜の膜中窒素濃度と抵抗率の関
係を示すグラフである。
FIG. 1 is a graph showing the relationship between the nitrogen concentration in the W nitride film and the resistivity.
Claims (1)
に用いられる抵抗素子において、該抵抗素子の抵
抗体の元素構成をタングステンあるいは40at.％
以内の窒素を成分として含む窒化タングステンと
し、かつ膜厚が1μｍ以下0.05μｍ以上なることを
特徴とする超電導回路用抵抗素子。1. In a resistance element used in a switching circuit made of a superconducting material, the elemental composition of the resistor of the resistance element is tungsten or 40at.%.
A resistance element for a superconducting circuit, characterized in that it is made of tungsten nitride containing nitrogen as a component, and has a film thickness of 1 μm or less and 0.05 μm or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60108288A JPS61267382A (en) | 1985-05-22 | 1985-05-22 | Resistance element for superconducting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60108288A JPS61267382A (en) | 1985-05-22 | 1985-05-22 | Resistance element for superconducting circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61267382A JPS61267382A (en) | 1986-11-26 |
| JPH0251267B2 true JPH0251267B2 (en) | 1990-11-06 |
Family
ID=14480863
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60108288A Granted JPS61267382A (en) | 1985-05-22 | 1985-05-22 | Resistance element for superconducting circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61267382A (en) |
-
1985
- 1985-05-22 JP JP60108288A patent/JPS61267382A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61267382A (en) | 1986-11-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |