JP3256707B2 - Dry etching method for copper thin film - Google Patents
Dry etching method for copper thin filmInfo
- Publication number
- JP3256707B2 JP3256707B2 JP34865692A JP34865692A JP3256707B2 JP 3256707 B2 JP3256707 B2 JP 3256707B2 JP 34865692 A JP34865692 A JP 34865692A JP 34865692 A JP34865692 A JP 34865692A JP 3256707 B2 JP3256707 B2 JP 3256707B2
- Authority
- JP
- Japan
- Prior art keywords
- etching
- thin film
- copper thin
- copper
- dry etching
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 239000010949 copper Substances 0.000 title claims description 46
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims description 43
- 229910052802 copper Inorganic materials 0.000 title claims description 43
- 238000000034 method Methods 0.000 title claims description 31
- 239000010409 thin film Substances 0.000 title claims description 24
- 238000001312 dry etching Methods 0.000 title claims description 16
- 238000005530 etching Methods 0.000 claims description 48
- 239000007789 gas Substances 0.000 claims description 16
- 238000001020 plasma etching Methods 0.000 claims description 13
- 150000001722 carbon compounds Chemical class 0.000 claims description 11
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims description 10
- 150000004678 hydrides Chemical class 0.000 claims description 8
- 150000002576 ketones Chemical class 0.000 claims description 7
- 239000001257 hydrogen Substances 0.000 claims description 6
- 229910052739 hydrogen Inorganic materials 0.000 claims description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 5
- 125000000217 alkyl group Chemical group 0.000 claims description 5
- 150000001875 compounds Chemical class 0.000 claims description 3
- 229910052731 fluorine Inorganic materials 0.000 claims description 3
- 239000011737 fluorine Substances 0.000 claims description 3
- 125000001153 fluoro group Chemical group F* 0.000 claims description 3
- 150000002170 ethers Chemical class 0.000 claims description 2
- 150000001298 alcohols Chemical class 0.000 claims 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 claims 1
- 230000000052 comparative effect Effects 0.000 description 8
- 239000010408 film Substances 0.000 description 7
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 6
- 229910052782 aluminium Inorganic materials 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 150000002500 ions Chemical class 0.000 description 5
- 229910021591 Copper(I) chloride Inorganic materials 0.000 description 4
- 150000004703 alkoxides Chemical class 0.000 description 4
- OXBLHERUFWYNTN-UHFFFAOYSA-M copper(I) chloride Chemical compound [Cu]Cl OXBLHERUFWYNTN-UHFFFAOYSA-M 0.000 description 4
- -1 Cl 2 and CCl 4 Chemical class 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 229910000838 Al alloy Inorganic materials 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910000881 Cu alloy Inorganic materials 0.000 description 2
- 125000003545 alkoxy group Chemical group 0.000 description 2
- 239000000460 chlorine Substances 0.000 description 2
- 150000001805 chlorine compounds Chemical class 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 230000005012 migration Effects 0.000 description 2
- 238000013508 migration Methods 0.000 description 2
- 239000012495 reaction gas Substances 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 102220491117 Putative postmeiotic segregation increased 2-like protein 1_C23F_mutation Human genes 0.000 description 1
- 229910003902 SiCl 4 Inorganic materials 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010494 dissociation reaction Methods 0.000 description 1
- 230000005593 dissociations Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 150000002366 halogen compounds Chemical class 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 229910052743 krypton Inorganic materials 0.000 description 1
- DNNSSWSSYDEUBZ-UHFFFAOYSA-N krypton atom Chemical compound [Kr] DNNSSWSSYDEUBZ-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Landscapes
- Drying Of Semiconductors (AREA)
- Internal Circuitry In Semiconductor Integrated Circuit Devices (AREA)
- ing And Chemical Polishing (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、半導体集積回路装置の
配線に使用される銅又は銅合金からなる薄膜をドライエ
ッチングする方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 dry etching a thin film made of copper or a copper alloy used for wiring of a semiconductor integrated circuit device.
【０００２】[0002]
【従来の技術】集積回路等の半導体装置の内部配線とし
て、現在一般にアルミニウム又はアルミニウム合金が用
いられている、集積度の向上による配線幅の微細化に伴
い、配線とその上に積層された保護膜層との間及び配線
とその下に積層された絶縁膜層との間の応力を起因とす
るストレスマイグレーション又は配線通電中のエレクト
ロマイグレーションによる配線の劣化及び切断が大きな
問題となっている。2. Description of the Related Art Aluminum or an aluminum alloy is generally used as an internal wiring of a semiconductor device such as an integrated circuit. With the miniaturization of the wiring width due to the improvement of the integration degree, the wiring and the protection layered thereon are protected. Degradation and disconnection of wiring due to stress migration due to stress between the film layer and between the wiring and the insulating film layer laminated thereunder or electromigration during wiring energization have become a serious problem.
【０００３】配線の劣化及び切断を防止するために、ア
ルミニウム中に銅等の元素を加えてアルミニウム自身の
耐性を高める方法が提案されている。また、特開平２−
119140号公報には、アルミニウム又はアルミニムウ合金
に代えて銅又は銅合金を配線材料として用いることが提
案されている。銅はアルミニウムと比べると以下の利点
を有する。 低抵抗であるためジュール発熱による温度上昇が小さ
いとともに急激な温度変化が少ない。 伝送遅延時間が短い。 高融点であるため高温強度に優れる。 原子量が大きいため、エレクトロマイグレーションや
ストレスマイグレーションが起きにくい。In order to prevent the deterioration and disconnection of wiring, a method has been proposed in which an element such as copper is added to aluminum to increase the resistance of aluminum itself. In addition, Japanese Unexamined Patent Application Publication No.
No. 119140 proposes to use copper or a copper alloy as a wiring material instead of aluminum or an aluminum alloy. Copper has the following advantages over aluminum. Due to the low resistance, the temperature rise due to Joule heat is small and there is little rapid temperature change. Transmission delay time is short. Excellent high-temperature strength due to high melting point. Since the atomic weight is large, electromigration and stress migration hardly occur.
【０００４】銅配線を形成するにはＣＶＤ法やＰＶＤ法
によって連続膜を形成し、フォトリソグラフィ技術及び
エッチング技術によりパターニング加工する必要があ
る。従来エッチングには化学反応を利用した湿式法が用
いられてきたが、エッチングが等方的であるためパター
ンのサイドエッチング量が大きくなり、制御性及び再現
性に劣るようになるので、近年著しく進歩したＶＬＳＩ
を製造するにあたり微細加工技術を施すことができな
い。In order to form a copper wiring, it is necessary to form a continuous film by a CVD method or a PVD method and pattern it by a photolithography technique and an etching technique. Conventionally, a wet method using a chemical reaction has been used for etching. However, since the etching is isotropic, the amount of side etching of the pattern becomes large, and the controllability and reproducibility are deteriorated. VLSI
Cannot be subjected to microfabrication technology in the production of
【０００５】そこで、ドライプロセスによるエッチング
方法が提案されている。例えば、Japan Journal of App
lied Physics、第28巻，第６号 L1070〜1072 (1989) や
Applied Physics Letter、第59巻，第８号 pp.914 〜91
6 (1991)には、塩化シラン(SiCl4) を用いた反応性イオ
ンエッチング(RIE) を行う方法がそれぞれ提案され、ま
た特開平２−239620号公報や特開平３−20484 号公報に
は塩素系ガスを用いてＲＩＥを行う方法が開示されてい
る。Accordingly, an etching method using a dry process has been proposed. For example, Japan Journal of App
lied Physics, Vol. 28, No. 6, L 1070-1072 (1989)
Applied Physics Letter, Vol. 59, No. 8, pp. 914-91
6 (1991) proposes a method of performing reactive ion etching (RIE) using silane chloride (SiCl 4 ), and JP-A-2-239620 and JP-A-3-20484 disclose a method of performing reactive ion etching (RIE). A method of performing RIE using a system gas is disclosed.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、銅はア
ルミニウムに比べて安定であるため、集積回路の形成プ
ロセスに許容される温度範囲内では揮発性のハロゲン化
合物を生成しにくい。従来のCl2, CCl4 等の塩素化合物
のみを用いたエッチングでは、銅をCuCl, CuCl2等の塩
化物として気化させている。例えば塩化銅（Ｉ）CuClの
沸点は約1400℃と高いので蒸気圧が低くなり、エッチン
グ速度が遅くなる。そのため銅のエッチング速度が非常
に遅いという問題は解決されていない。エッチング速度
を高めるためには特開平２−239620号公報に開示されて
いるように基板温度を250 ℃以上に上げなければならな
いが、その場合有機レジスト層がダメージを受けてしま
い、微細加工性に劣るようになる。さらに、高アスペク
ト比のエッチングを行う際は、サイドエッチングを来す
ことも判明した。However, since copper is more stable than aluminum, volatile halogen compounds are less likely to be generated within a temperature range allowed for an integrated circuit forming process. In conventional etching using only chlorine compounds such as Cl 2 and CCl 4 , copper is vaporized as chlorides such as CuCl and CuCl 2 . For example, the boiling point of copper (I) chloride, CuCl, is as high as about 1400 ° C., so that the vapor pressure is low and the etching rate is low. Therefore, the problem that the etching rate of copper is very slow has not been solved. In order to increase the etching rate, the substrate temperature must be raised to 250 ° C. or higher as disclosed in Japanese Patent Application Laid-Open No. 2-239620, in which case the organic resist layer is damaged, resulting in poor fine workability. Become inferior. Further, it has been found that when etching with a high aspect ratio is performed, side etching occurs.
【０００７】本発明は以上の問題点を解決するものであ
り、低温でもエッチング速度が高く、かつ、高アスペク
ト比のエッチングを行う際にも高精度で微細な異方性エ
ッチングを行える反応性イオンエッチングによって銅薄
膜をドライエッチングする方法を提供することを目的と
するものである。The present invention has been made to solve the above problems, and has a high etching rate even at a low temperature, and a reactive ion capable of performing fine and anisotropic etching with high precision even when etching with a high aspect ratio. It is an object of the present invention to provide a method for dry etching a copper thin film by etching.
【０００８】[0008]
【課題を解決するための手段】本発明による銅薄膜のド
ライエッチング方法は、銅薄膜をドライエッチングする
際に、エーテル、ケトンの内から選ばれた炭素化合物と
ＶＢ族水素化物とを混合したエッチングガスを用いて反
応性イオンエッチングを行うことを特徴とするものであ
る。なお、炭素化合物として、アルコールを用いること
もできる。The dry etching method for a copper thin film according to the present invention is a method for dry etching a copper thin film by mixing a carbon compound selected from ether and ketone with a VB group hydride. The reactive ion etching is performed using a gas. In addition, alcohol can also be used as a carbon compound.
【０００９】[0009]
【作用】本発明による銅薄膜のドライエッチング方法で
は、エーテル、ケトンの内から選ばれた炭素化合物をプ
ラズマ中で種々の不安定分子に解離した後に再結合及び
解離を繰り返すことにより反応性の高いラジカルを発生
させる。このラジカルのうち活性アルコキシル基RO* は
銅と反応し、(RO)ｎ Cu* といったアルコキシド中間体
が銅表面に発生する。このアルコキシド中間体は単体で
は不安定であることも多いので、ＶＢ族水素化物を付加
させて安定な中間体とする。得られた中間体は塩素化物
と比べると高い蒸気圧を有するので、低圧のプラズマプ
ロセスであるＲＩＥにおいても銅表面から脱離して気相
中に拡散していく。以上の過程により、低温で高いエッ
チング速度が得られる。なお、炭素化合物としてアルコ
ールを用いた場合にも、同様な効果が得られる。In the method of dry etching a copper thin film according to the present invention, a carbon compound selected from ethers and ketones is dissociated into various unstable molecules in a plasma and then recombined and dissociated repeatedly, thereby achieving high reactivity. Generates radicals. Among these radicals, the active alkoxyl group RO * reacts with copper, and an alkoxide intermediate such as (RO) nCu * is generated on the copper surface. Since this alkoxide intermediate is often unstable by itself, a hydride is added to form a stable intermediate. Since the obtained intermediate has a higher vapor pressure than the chlorinated product, it is desorbed from the copper surface and diffused into the gas phase even in RIE, which is a low-pressure plasma process. Through the above process, a high etching rate can be obtained at a low temperature. The same effect can be obtained when alcohol is used as the carbon compound.
【００１０】また、本発明による銅薄膜のドライエッチ
ング方法では、各種イオンを積極的に銅の加工底部に導
入して異方性の高い加工が施され、また銅の側壁部では
イオン照射が弱い上にCuとＶＢ族元素との準安定化合物
が生成して銅表面を保護するので、銅の側壁部のエッチ
ング速度が低くなり、高アスペクト比のエッチングを行
う際にも高精度で超微細な異方性エッチングを行うこと
ができる。In the dry etching method for a copper thin film according to the present invention, various ions are positively introduced into the copper processing bottom to perform processing with high anisotropy, and ion irradiation is weak on the copper side wall. Since a metastable compound of Cu and a VB group element is formed on the surface to protect the copper surface, the etching rate of the side wall of the copper is reduced, and even when performing etching with a high aspect ratio, ultra-fine and ultra-fine Anisotropic etching can be performed.
【００１１】[0011]
【実施例】以下、本発明の銅のエッチング方法の実施例
を図面を参照して詳細に説明する。図１に、本発明の実
施例及び比較例を実施するＲＩＥ装置の概念図を示す。
また図２に本発明の実施例１〜４と比較例１，２で出発
材料として使用されるウェファ１の断面図を示す。ウェ
ファ１は、基板31と、基板31の上に積層された膜厚0.4
μm の銅薄膜32と、銅薄膜32の上に積層された膜厚0.4
μm 、膜幅0.6 μm、膜間隔0.3 μm のレジスト層33と
を有している。以下、工程を説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the copper etching method of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a conceptual diagram of an RIE apparatus for implementing an embodiment of the present invention and a comparative example.
FIG. 2 is a sectional view of a wafer 1 used as a starting material in Examples 1 to 4 and Comparative Examples 1 and 2 of the present invention. The wafer 1 has a substrate 31 and a film thickness of 0.4
μm of the copper thin film 32 and a film thickness of 0.4
and a resist layer 33 having a film width of 0.6 μm and a film interval of 0.3 μm. Hereinafter, the steps will be described.
【００１２】まず、図２のウェファ１をエッチングチャ
ンバ２内の高周波電極を兼ねるステージ３に装着し、排
気装置４により真空排気を行った後、ヒータ５を用いて
ステージ３を加熱する。次にエッチングチャンバ２内に
ガスボンベ６からガス流量調整器７を介して反応ガスを
供給し、図示しない圧力制御装置を用いて0.1 〜100mTo
rr( ここでは20mTorr)に制御し、高周波電源８から50〜
500MHz( ここでは13.56MHz) の高周波を整合器９を介し
てステージ３と陰極10の間に印加してプラズマ11を発生
させ、エッチングを行った。First, the wafer 1 shown in FIG. 2 is mounted on the stage 3 serving also as a high-frequency electrode in the etching chamber 2, and the exhaust device 4 is evacuated to vacuum. Then, the stage 3 is heated using the heater 5. Next, a reaction gas is supplied from the gas cylinder 6 into the etching chamber 2 via the gas flow rate regulator 7, and the pressure is controlled to 0.1 to 100 m
rr (in this case, 20 mTorr), and 50-
A high frequency of 500 MHz (13.56 MHz in this case) was applied between the stage 3 and the cathode 10 through the matching unit 9 to generate a plasma 11, and etching was performed.
【００１３】以上の工程を、実施例１〜４及び比較例
１，２について表１に示したエッチングガスを用い、か
つステージ温度に設定して行い、エッチング速度及びエ
ッチング後の加工形状を調べた。化学式の下の数字はそ
れぞれガス分圧(mTorr) を示す。得られた結果を表１及
び図３〜５に示す。なお、炭素化合物は温浴して気化さ
せ、必要な流量をそれぞれ確保し、また各流量について
は排気装置４の排気速度とエッチングチャンバ２内の圧
力によって決定し、50〜100sccm とした。The above steps were carried out for Examples 1 to 4 and Comparative Examples 1 and 2 by using the etching gas shown in Table 1 and setting the stage temperature, and the etching rate and the processed shape after etching were examined. . The numbers below the chemical formulas indicate the gas partial pressure (mTorr). The obtained results are shown in Table 1 and FIGS. The carbon compound was vaporized in a warm bath to secure necessary flow rates, and each flow rate was determined by the exhaust speed of the exhaust device 4 and the pressure in the etching chamber 2, and was set to 50 to 100 sccm.
【００１４】[0014]
【表１】 [Table 1]
【００１５】表１より、実施例１〜４では130 ℃の低い
ステージ温度で12000 Å／分の高いエッチング速度を得
られることがわかる。一方、比較例１，２では250 ℃の
高いステージ温度でもエッチング速度は4000Å／分又は
1000Å／分と低いのがわかる。Table 1 shows that in Examples 1 to 4, a high etching rate of 12000 ° / min can be obtained at a low stage temperature of 130 ° C. On the other hand, in Comparative Examples 1 and 2, even at a high stage temperature of 250 ° C., the etching rate was 4000 ° / min.
It can be seen that it is as low as 1000 l / min.
【００１６】図３に実施例１，２，３, ４におけるエッ
チング加工後のウェファ1aの断面図を示す。銅薄膜32a
はレジスト33a のパターンに従って良好にエッチングさ
れている。図４に比較例１におけるエッチング加工後の
ウェファ1bの断面図を示す。銅薄膜32b にはサイドエッ
チングが生じている。図５に比較例２におけるエッチン
グ加工後のウェファ1cの断面図を示す。銅薄膜32c は十
分にエッチングが施されていない。このように、本発明
の実施例１〜４では低温でもエッチング速度が高く、か
つ、サイドエッチング又はエッチング不足が生じないこ
とが確認された。FIG. 3 is a sectional view of the wafer 1a after the etching process in the first, second, third and fourth embodiments. Copper thin film 32a
Is well etched according to the pattern of the resist 33a. FIG. 4 shows a cross-sectional view of the wafer 1b after etching in Comparative Example 1. Side etching has occurred in the copper thin film 32b. FIG. 5 shows a cross-sectional view of the wafer 1c after etching in Comparative Example 2. The copper thin film 32c is not sufficiently etched. Thus, in Examples 1 to 4 of the present invention, it was confirmed that the etching rate was high even at a low temperature, and that side etching or insufficient etching did not occur.
【００１７】なお、本発明で用いるＶＢ族水素化合物と
しては、NH3, AsH3, PH3等を用いるのが好ましい。これ
らは一種類のみ用いても二種類以上用いてもよい。ま
た、ＶＢ族水素化合物の水素（Ｈ）をフッ素（Ｆ）やア
ルキル基等で置換したものを用いてもよい。As the VB group hydrogen compound used in the present invention, it is preferable to use NH 3 , AsH 3 , PH 3 and the like. These may be used alone or in combination of two or more. Alternatively, a hydrogen compound of the VB group in which hydrogen (H) is substituted with fluorine (F), an alkyl group, or the like may be used.
【００１８】また、アルコール、エーテル又はケトン中
のアルキル基は特に限定されないが、CH3, C2H5, C3H7,
C4H9, C5H11等が好ましい。これらは一種類のみ用いて
も二種類以上用いてもよい。またアルキル基中の一部又
は全部の水素（Ｈ）をフッ素（Ｆ）に置換したものを用
いてもよい。The alkyl group in the alcohol, ether or ketone is not particularly limited, but may be CH 3 , C 2 H 5 , C 3 H 7 ,
C 4 H 9 and C 5 H 11 are preferred. These may be used alone or in combination of two or more. Further, an alkyl group in which part or all of hydrogen (H) is replaced with fluorine (F) may be used.
【００１９】また、炭素化合物及びＶＢ族水素化物の分
圧、ステージ温度は加工形状や装置の条件によって異な
るので、表１の実施例に限定されないが、ステージ温度
は常温から300 ℃が好ましく、分圧はいずれも0.1 〜10
0mTorrが好ましく、また両者の分圧の比は0.01〜100 が
好ましい。The partial pressure of the carbon compound and the hydride of the VB group and the stage temperature are different depending on the processing shape and the conditions of the apparatus. Therefore, the stage temperature is not limited to the embodiment shown in Table 1, but the stage temperature is preferably from room temperature to 300 ° C. All pressures are 0.1 to 10
The pressure is preferably 0 mTorr, and the ratio of the two partial pressures is preferably 0.01 to 100.
【００２０】また、反応ガスとしては必要に応じて炭素
化合物とＶＢ族水素化物以外のガスを添加してもよい。
プラズマ媒体としての添加ガスとして、アルゴン、窒
素、ヘリウム、クリプトン、酸素、水素等を挙げること
ができる。添加したガスの分圧は特定できないが、プラ
ズマ媒体として添加した場合には0.01〜10,000mTorr で
ある。As the reaction gas, a gas other than the carbon compound and the hydride of the VB group may be added as necessary.
Examples of the additional gas as the plasma medium include argon, nitrogen, helium, krypton, oxygen, and hydrogen. Although the partial pressure of the added gas cannot be specified, it is 0.01 to 10,000 mTorr when added as a plasma medium.
【００２１】[0021]
【発明の効果】本発明の銅のドライエッチング方法によ
れば、アルコール、エーテル、ケトンの内から選ばれた
炭素化合物をプラズマ中で種々の不安定分子に解離した
後に再結合及び解離を繰り返すことにより反応性の高い
ラジカルを発生させる。このラジカルのうち活性アルコ
キシル基RO* は銅と反応し、(RO)n Cu* といったアルコ
キシド中間体が銅表面に発生する。このアルコキシド中
間体は単体では不安定であることも多いので、ＶＢ族水
素化物を付加させて安定な中間体とする。得られた中間
体は塩素化物と比べると高い蒸気圧を有するので、低圧
のプラズマプロセスであるＲＩＥにおいても銅表面から
脱離して気相中に拡散していく。以上の過程により、低
温で高いエッチング速度が得られるという効果を有す
る。また、本発明による銅薄膜のドライエッチング方法
によれば、各種イオンを積極的に銅薄膜の加工底部に導
入して異方性の高い加工が施され、また銅薄膜の側壁部
ではイオン照射が弱い上にCuとＶＢ族元素との準安定化
合物が生成して銅薄膜の表面を保護するので、銅薄膜の
側壁部のエッチング速度が低くなり、高アスペクト比の
エッチングを行う際にも高精度で超微細な異方性エッチ
ングを行うことができるという効果を有する。According to the dry etching method of copper of the present invention, recombination and dissociation are repeated after dissociating a carbon compound selected from alcohol, ether and ketone into various unstable molecules in plasma. To generate highly reactive radicals. Among these radicals, the active alkoxyl group RO * reacts with copper, and an alkoxide intermediate such as (RO) n Cu * is generated on the copper surface. Since this alkoxide intermediate is often unstable by itself, a hydride is added to form a stable intermediate. Since the obtained intermediate has a higher vapor pressure than the chlorinated product, it is desorbed from the copper surface and diffused into the gas phase even in RIE, which is a low-pressure plasma process. The above process has an effect that a high etching rate can be obtained at a low temperature. Further, according to the dry etching method for a copper thin film according to the present invention, various ions are positively introduced into the processing bottom of the copper thin film to perform highly anisotropic processing, and ion irradiation is performed on the side wall of the copper thin film. In addition to the weakness, a metastable compound of Cu and the VB group element is formed to protect the surface of the copper thin film, so the etching rate on the side wall of the copper thin film is reduced, and high accuracy is achieved even when etching with a high aspect ratio. Has the effect that ultrafine anisotropic etching can be performed.
【図１】本発明を実施するＲＩＥ装置の概念図を示す。FIG. 1 shows a conceptual diagram of an RIE apparatus embodying the present invention.
【図２】エッチング加工前のウェファの断面図を示す。FIG. 2 shows a cross-sectional view of a wafer before etching.
【図３】実施例１，２，３，４におけるエッチング加工
後のウェファの断面図を示す。FIG. 3 is a cross-sectional view of a wafer after etching in Examples 1, 2, 3, and 4.
【図４】比較例１におけるエッチング加工後のウェファ
の断面図を示す。FIG. 4 shows a cross-sectional view of a wafer after etching in Comparative Example 1.
【図５】比較例２におけるエッチング加工後のウェファ
の断面図を示す。FIG. 5 shows a cross-sectional view of a wafer after etching in Comparative Example 2.
1,1a, 1b, 1c ウェファ ２ エッチングチャンバ ３ ステージ ４ 排気装置 ５ ヒータ ６ ガスボンベ ７ ガス流量調整器 ８ 高周波電源 ９ 整合器 10 陰極 11 プラズマ 31 基板 32, 32a, 32b, 32c 銅薄膜 33, 33a, 33b, 33c レジスト層 1,1a, 1b, 1c Wafer 2 Etching chamber 3 Stage 4 Exhaust device 5 Heater 6 Gas cylinder 7 Gas flow regulator 8 High frequency power supply 9 Matching device 10 Cathode 11 Plasma 31 Substrate 32, 32a, 32b, 32c Copper thin film 33, 33a, 33b, 33c resist layer
フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) H01L 21/3065 C23F 4/00 Continuation of the front page (58) Field surveyed (Int.Cl. 7 , DB name) H01L 21/3065 C23F 4/00
Claims (4)
ーテル、ケトンの内から選ばれた炭素化合物と、ＶＢ族
水素化物とを混合したエッチングガスを用いて反応性イ
オンエッチングを行うことを特徴とする銅薄膜のドライ
エッチング方法。In a dry etching of a copper thin film, reactive ion etching is performed by using an etching gas in which a carbon compound selected from ether and ketone and a VB group hydride are mixed. Dry etching method for copper thin film.
ルコール、エーテル、ケトンの内から選ばれた炭素化合
物と、Ｐ又はAsの水素化物とを混合したエッチングガス
を用いて反応性イオンエッチングを行うことを特徴とす
る銅薄膜のドライエッチング方法。2. When dry etching a copper thin film, reactive ion etching is performed using an etching gas in which a carbon compound selected from alcohol, ether and ketone and a hydride of P or As are mixed. A dry etching method for a copper thin film, characterized in that:
ルコール、エーテル、ケトンの内から選ばれ、アルキル
基の水素（Ｈ）の一部又は全部をフッ素（Ｆ）に置換し
た化合物と、ＶＢ族水素化物とを混合したエッチングガ
スを用いて反応性イオンエッチングを行うことを特徴と
する銅薄膜のドライエッチング方法。3. A dry etching method for a copper thin film, comprising a compound selected from alcohols, ethers and ketones, wherein a part or all of hydrogen (H) of an alkyl group is substituted by fluorine (F); A dry etching method for a copper thin film, wherein reactive ion etching is performed using an etching gas mixed with a hydride.
C２H５, C３H７, C４H９又はC５H１１ であることを特
徴とする請求項１ないし３のいずれかに記載の銅薄膜の
ドライエッチング方法。4. An alkyl group in the carbon compound is CH3,
4. The dry etching method for a copper thin film according to claim 1, wherein the method is C2H5, C3H7, C4H9 or C5H11.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34865692A JP3256707B2 (en) | 1992-12-28 | 1992-12-28 | Dry etching method for copper thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34865692A JP3256707B2 (en) | 1992-12-28 | 1992-12-28 | Dry etching method for copper thin film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06204186A JPH06204186A (en) | 1994-07-22 |
| JP3256707B2 true JP3256707B2 (en) | 2002-02-12 |
Family
ID=18398476
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP34865692A Expired - Fee Related JP3256707B2 (en) | 1992-12-28 | 1992-12-28 | Dry etching method for copper thin film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3256707B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2972786B2 (en) * | 1996-11-05 | 1999-11-08 | 工業技術院長 | Dry etching gas |
| JP5728221B2 (en) | 2010-12-24 | 2015-06-03 | 東京エレクトロン株式会社 | Substrate processing method and storage medium |
| US8633117B1 (en) | 2012-11-07 | 2014-01-21 | International Business Machines Corporation | Sputter and surface modification etch processing for metal patterning in integrated circuits |
| US8871107B2 (en) | 2013-03-15 | 2014-10-28 | International Business Machines Corporation | Subtractive plasma etching of a blanket layer of metal or metal alloy |
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1992
- 1992-12-28 JP JP34865692A patent/JP3256707B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06204186A (en) | 1994-07-22 |
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