JP3116414B2 - Dry etching method - Google Patents
Dry etching methodInfo
- Publication number
- JP3116414B2 JP3116414B2 JP03118959A JP11895991A JP3116414B2 JP 3116414 B2 JP3116414 B2 JP 3116414B2 JP 03118959 A JP03118959 A JP 03118959A JP 11895991 A JP11895991 A JP 11895991A JP 3116414 B2 JP3116414 B2 JP 3116414B2
- Authority
- JP
- Japan
- Prior art keywords
- film
- etching
- gas
- halogen
- 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
- 238000000034 method Methods 0.000 title claims description 20
- 238000001312 dry etching Methods 0.000 title claims description 6
- 238000005530 etching Methods 0.000 claims description 14
- 229910052736 halogen Inorganic materials 0.000 claims description 9
- 150000002367 halogens Chemical class 0.000 claims description 9
- 239000007795 chemical reaction product Substances 0.000 claims description 3
- 230000001681 protective effect Effects 0.000 claims description 3
- 239000000047 product Substances 0.000 claims 1
- 239000007789 gas Substances 0.000 description 14
- 229910017855 NH 4 F Inorganic materials 0.000 description 8
- 239000010410 layer Substances 0.000 description 8
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- DDFHBQSCUXNBSA-UHFFFAOYSA-N 5-(5-carboxythiophen-2-yl)thiophene-2-carboxylic acid Chemical compound S1C(C(=O)O)=CC=C1C1=CC=C(C(O)=O)S1 DDFHBQSCUXNBSA-UHFFFAOYSA-N 0.000 description 2
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 229910018503 SF6 Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- -1 ammonium halide Chemical class 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- NBVXSUQYWXRMNV-UHFFFAOYSA-N fluoromethane Chemical compound FC NBVXSUQYWXRMNV-UHFFFAOYSA-N 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000011229 interlayer Substances 0.000 description 1
- 238000001459 lithography Methods 0.000 description 1
- QKCGXXHCELUCKW-UHFFFAOYSA-N n-[4-[4-(dinaphthalen-2-ylamino)phenyl]phenyl]-n-naphthalen-2-ylnaphthalen-2-amine Chemical compound C1=CC=CC2=CC(N(C=3C=CC(=CC=3)C=3C=CC(=CC=3)N(C=3C=C4C=CC=CC4=CC=3)C=3C=C4C=CC=CC4=CC=3)C3=CC4=CC=CC=C4C=C3)=CC=C21 QKCGXXHCELUCKW-UHFFFAOYSA-N 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- SFZCNBIFKDRMGX-UHFFFAOYSA-N sulfur hexafluoride Chemical compound FS(F)(F)(F)(F)F SFZCNBIFKDRMGX-UHFFFAOYSA-N 0.000 description 1
- 229960000909 sulfur hexafluoride Drugs 0.000 description 1
- FAQYAMRNWDIXMY-UHFFFAOYSA-N trichloroborane Chemical compound ClB(Cl)Cl FAQYAMRNWDIXMY-UHFFFAOYSA-N 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
- 230000004304 visual acuity Effects 0.000 description 1
Landscapes
- Physical Vapour Deposition (AREA)
- Electrodes Of Semiconductors (AREA)
- Drying Of Semiconductors (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、半導体装置の製造プロ
セスにおける有機膜を選択的にエッチングする方法であ
って、特に２層レジスト法や３層レジスト法等の多層レ
ジスト技術に係るドライ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 a method for selectively etching an organic film in a semiconductor device manufacturing process, and more particularly to a dry etching method according to a multilayer resist technique such as a two-layer resist method or a three-layer resist method. About.
【０００２】[0002]
【従来の技術】近年、メモリ素子の高集積化，微細化へ
の傾向は著しく、６４ＭＤＲＡＭ，１６ＭＳＲＡＭの製
造を目的とした開発が行なわれている。このようなデバ
イスでは、パターンルールとして０．３５μｍクラスの
微細加工が要求されており、ＫｒＦエキシマレーザリソ
グラフィが、この微細加工達成の最有力技術と考えられ
ている。しかし、段差を有する実デバイス構造では、下
地からの光反射などにより、解像力が低下する問題をか
かえている。2. Description of the Related Art In recent years, there has been a remarkable tendency toward high integration and miniaturization of memory elements, and development for the purpose of manufacturing 64 MDRAM and 16 MSRAM has been carried out. In such a device, fine processing of 0.35 μm class is required as a pattern rule, and KrF excimer laser lithography is considered to be the most prominent technique for achieving this fine processing. However, the actual device structure having a step has a problem that the resolving power is reduced due to light reflection from a base or the like.
【０００３】そこで、パターンの異方性形状を実現する
方法として多層レジストプロセスが必須となってきてい
る。しかし、多層レジストの異方性加工を制御性良く高
速で行なうことは容易ではない。下層レジストのエッチ
ングガスに主として用いられている酸素（Ｏ2）では異
方性加工が困難で、必然的に低圧で、しかも高い直流電
圧条件が必要である。また、この方法においては、スパ
ッタリング効果が大きく、下地材料がスパッタされ側壁
に再付着する問題や、マスクとなる材料との選択比が大
きくとれないなどの問題がある。Therefore, a multilayer resist process has become indispensable as a method for realizing an anisotropic shape of a pattern. However, it is not easy to perform anisotropic processing of a multilayer resist at high speed with good controllability. Oxygen (O 2 ), which is mainly used as an etching gas for the lower layer resist, is difficult to anisotropically process, and inevitably requires low pressure and high DC voltage conditions. In addition, this method has a problem that the sputtering effect is large and the underlying material is sputtered and re-adhered to the side wall, and that the selectivity with respect to the material serving as a mask cannot be made large.
【０００４】このような問題を解決するための手段とし
て、特開平１−２８０３１６号公報記載の方法が知られ
ている。この方法は、低反応性ガスとしてＮＨ3を用い
て下層レジストをエッチングし、異方性加工を図ったも
のである。As a means for solving such a problem, a method described in Japanese Patent Application Laid-Open No. 1-280316 is known. In this method, the lower layer resist is etched by using NH 3 as a low-reactivity gas to achieve anisotropic processing.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、上記し
た従来技術にあっては、ＮＨ3ガスを用いても、ＥＣＲ
のような高密度プラズマタイプのエッチャでは異方性加
工が困難であるという問題がある。このため、ウエハを
低温にするエッチングなどが検討されているものの、実
用化を考えると室温程度のプロセスの確立が切望されて
いる。However, in the above-mentioned prior art, even if NH 3 gas is used, the ECR
Such a high-density plasma type etcher has a problem that it is difficult to perform anisotropic processing. For this reason, although etching for lowering the temperature of the wafer has been studied, establishment of a process at about room temperature has been keenly considered in consideration of practical use.
【０００６】本発明は、このような従来の問題点に着目
して創案されたものであって、有機膜の高精度異方性加
工を低直流電圧で達成できるドライエッチング方法を得
んとするものである。SUMMARY OF THE INVENTION The present invention has been made in view of such conventional problems, and an object thereof is to provide a dry etching method capable of achieving high-precision anisotropic processing of an organic film at a low DC voltage. Things.
【０００７】[0007]
【課題を解決するための手段】そこで、本発明は、エッ
チングガスとしてＮＨ 3 とハロゲンを含むガスを用い
て、下地層上に形成された有機膜を選択的にエッチング
すると共に、前記ハロゲンの量を制御してＮＨ 3 とハロ
ゲンとの反応生成物を生成し、その反応生成物により前
記有機膜の側壁に対して保護膜を形成したことを、その
解決方法としている。Means for Solving the Problems] The present invention has edge
Using a gas containing NH 3 and halogen as the etching gas
Then, the organic film formed on the underlayer is selectively etched, and the amount of the halogen is controlled to control NH 3 and halogen.
To produce a reaction product with
The solution is to form a protective film on the side wall of the organic film .
【０００８】[0008]
【作用】エッチングガスに、ＮＨ3と例えばＳＦ6等のハ
ロゲンを含むガスを用いることにより、放電によってハ
ロゲン化アンモニウム（例えばＮＨ4Ｆ）を生成させ、
有機膜の側壁を保護する作用がある。例えば、フッ化ア
ンモニウム（ＮＨ4Ｆ）は、融点１２４℃であるが昇華
性があり、融点に達しなくても気化作用はある。この場
合、側壁保護に寄与する分だけＳＦ6等のフッ素系ガス
を添加すれば良く、少量でも異方性は得られる。By using a gas containing NH 3 and a halogen such as SF 6 as an etching gas, an ammonium halide (eg, NH 4 F) is generated by electric discharge,
It has the function of protecting the side wall of the organic film. For example, ammonium fluoride (NH 4 F) has a melting point of 124 ° C., but is sublimable, and has a vaporizing action even if the melting point is not reached. In this case, a fluorine-based gas such as SF 6 may be added in an amount that contributes to the protection of the side wall, and anisotropy can be obtained even with a small amount.
【０００９】[0009]
【実施例】以下、本発明に係るドライエッチング方法の
詳細を図面に示す実施例に基づいて説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the dry etching method according to the present invention will be described below based on embodiments shown in the drawings.
【００１０】（第１実施例）図１及び図２は、本発明の
第１実施例を示している。本実施例は、層間膜としての
ＳｉＯ2膜１上に形成したアルミニウム膜２を加工する
ためのエッチング用マスクとして３層レジスト技術を用
いた例である。(First Embodiment) FIGS. 1 and 2 show a first embodiment of the present invention. This embodiment is an example in which a three-layer resist technique is used as an etching mask for processing an aluminum film 2 formed on a SiO 2 film 1 as an interlayer film.
【００１１】図１は、アルミニウム膜２上に、有機膜と
しての下層レジスト膜３が形成され、下層レジスト膜３
上に形成した中間層としてのＳＯＧ（Ｓｐｉｎ Ｏｎ
Ｇｌａｓｓ）膜４がパターニングされた状態を示してい
る。FIG. 1 shows a lower resist film 3 as an organic film formed on an aluminum film 2.
SOG (Spin On) as an intermediate layer formed thereon
(Glass) film 4 is patterned.
【００１２】次に、同図に示すように、ＳＯＧ膜４をマ
スクとして、ＲＦバイアス印加型のＥＣＲエッチャを用
いて以下に示す条件で下層レジスト膜３のエッチングを
行なう。Next, as shown in FIG. 1, using the SOG film 4 as a mask, the lower resist film 3 is etched using an ECR etcher of an RF bias application type under the following conditions.
【００１３】 このようなエッチングに際しては、図２に示すよう
に、反応生成物であるフッ化アンモニウム（ＮＨ4Ｆ）
が、エッチングされた下層レジスト膜３の側壁に付着し
てＮＨ4Ｆ膜５を形成し、このＮＨ4Ｆ膜５が側壁保護に
寄与して異方性加工を可能にしている。[0013] In such etching, as shown in FIG. 2, ammonium fluoride (NH 4 F) which is a reaction product is used.
But attached to the side wall of the lower resist film 3 is etched to form a NH 4 F film 5, the NH 4 F film 5 is to enable anisotropic processing contributes to sidewall protection.
【００１４】なお、上記したような高密度プラズマ形成
タイプのエッチャでは、アンモニア（ＮＨ3）単独，常
温での異方性加工は困難である。また、アンモニアガス
に添加するＳＦ6の流量をコントロールすることによ
り、ＮＨ4Ｆの堆積を制御することが可能であり、これ
により下層レジスト膜３の断面形状の制御が可能とな
る。In the above-described etcher of the high-density plasma formation type, it is difficult to carry out anisotropic processing at normal temperature with ammonia (NH 3 ) alone. Further, by controlling the flow rate of SF 6 added to the ammonia gas, it is possible to control the deposition of NH 4 F, thereby controlling the cross-sectional shape of the lower resist film 3.
【００１５】（第２実施例）本実施例は、上記第１実施
例と同様のＲＦバイアス印加型のＥＣＲエッチャを用
い、以下の条件でＳＯＧ膜４をマスクとして下層レジス
ト膜３のエッチングを行なう。(Second Embodiment) In this embodiment, the lower resist film 3 is etched using the SOG film 4 as a mask under the following conditions, using the same RF bias application type ECR etcher as in the first embodiment. .
【００１６】 この場合、エッチングガスの比は、上記第１実施例と
同一であるが、ウエハ温度が２０℃であるため、図３に
示すように、ＮＨ4Ｆの堆積が保進され、下層レジスト
膜３の断面形状は、テーパ形状となる。[0016] In this case, the etching gas ratio is the same as that of the first embodiment, but since the wafer temperature is 20 ° C., the deposition of NH 4 F is promoted as shown in FIG. Has a tapered shape.
【００１７】以上、実施例について説明したが、本発明
は、これらに限定されるものではなく、各種の設計変更
が可能である。Although the embodiments have been described above, the present invention is not limited to these embodiments, and various design changes are possible.
【００１８】例えば、上記両実施例においては、アンモ
ニア（ＮＨ3）ガスに、ハロゲンを含むガスとして六フ
ッ化イオウ（ＳＦ6）を添加したが、この他三フッ化窒
素（ＮＦ3），四フッ化炭素（ＣＦ4）等のフッ素系ガス
や、三塩化ホウ素（ＢＣｌ3），や塩化水素（ＨＣｌ）
等の塩素系ガスや、Ｂｒ2，ＨＢｒ，ＢＢｒ3等のハロゲ
ン系ガスを添加しても側壁保護作用を有する膜（保護
膜）を形成することが可能である。For example, in both of the above embodiments, sulfur hexafluoride (SF 6 ) was added as a gas containing halogen to ammonia (NH 3 ) gas. In addition, nitrogen trifluoride (NF 3 ) Fluorine gas such as fluorocarbon (CF 4 ), boron trichloride (BCl 3 ), and hydrogen chloride (HCl)
And chlorine-based gas and the like, Br 2, HBr, films having a sidewall protection effect be added to the halogen-based gas such as BBr 3 (protective
Film) can be formed.
【００１９】また、本発明においては、エッチングレー
トを増大させるために、酸素（Ｏ2），窒素（Ｎ2），水
素（Ｈ2）を添加することも可能である。In the present invention, oxygen (O 2 ), nitrogen (N 2 ), and hydrogen (H 2 ) can be added to increase the etching rate.
【００２０】さらに、エッチング時のウエハ温度は、エ
ッチング条件，エッチング形状に応じて適宜選択するこ
とが可能である。Further, the wafer temperature at the time of etching can be appropriately selected according to the etching conditions and the etching shape.
【００２１】[0021]
【発明の効果】以上の説明から明らかなように、本発明
に係るドライエッチング方法によれば、有機膜異方性加
工を室温程度でしかも低直流電流条件で高精度に行なう
ことを可能にする効果がある。As is clear from the above description, according to the dry etching method of the present invention, it is possible to perform anisotropic processing of an organic film at a room temperature and at a low DC current condition with high accuracy. effective.
【００２２】このため、例えば多層レジストの高精度加
工が可能となり、下地層の加工をも高精度に行なえる効
果がある。For this reason, for example, high-precision processing of a multi-layer resist becomes possible, and there is an effect that the processing of the underlayer can also be performed with high precision.
【図１】本発明の第１実施例の工程を示す断面図。FIG. 1 is a sectional view showing a process of a first embodiment of the present invention.
【図２】本発明の第１実施例の工程を示す断面図。FIG. 2 is a cross-sectional view showing the steps of the first embodiment of the present invention.
【図３】本発明の第２実施例の断面図。FIG. 3 is a sectional view of a second embodiment of the present invention.
２…アルミニウム膜（下地層）、３…下層レジスト膜
（有機膜）、４…ＳＯＧ膜、５…ＮＨ4Ｆ膜。2 ... aluminum film (base layer), 3 ... lower resist film (organic film), 4 ... SOG film, 5 ... NH 4 F film.
Claims (1)
を含むガスを用いて、下地層上に形成された有機膜を選
択的にエッチングすると共に、 前記ハロゲンの量を制御してＮＨ 3 とハロゲンとの反応
生成物を生成し、その反応生成物により前記有機膜の側
壁に対して保護膜を形成したことを 特徴とするドライエ
ッチング方法。1. An etching gas comprising NH 3 and halogen.
By using a gas containing, together with a selectively etching the organic film formed on the underlying layer, the reaction between the NH 3 and the halogen by controlling the amount of the halogen
A product is produced, and the reaction product produces
A dry etching method, wherein a protective film is formed on a wall .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03118959A JP3116414B2 (en) | 1991-05-24 | 1991-05-24 | Dry etching method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03118959A JP3116414B2 (en) | 1991-05-24 | 1991-05-24 | Dry etching method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04346227A JPH04346227A (en) | 1992-12-02 |
| JP3116414B2 true JP3116414B2 (en) | 2000-12-11 |
Family
ID=14749514
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03118959A Expired - Fee Related JP3116414B2 (en) | 1991-05-24 | 1991-05-24 | Dry etching method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3116414B2 (en) |
-
1991
- 1991-05-24 JP JP03118959A patent/JP3116414B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04346227A (en) | 1992-12-02 |
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