JPS6043829A - Dry etching method - Google Patents
Dry etching methodInfo
- Publication number
- JPS6043829A JPS6043829A JP15143683A JP15143683A JPS6043829A JP S6043829 A JPS6043829 A JP S6043829A JP 15143683 A JP15143683 A JP 15143683A JP 15143683 A JP15143683 A JP 15143683A JP S6043829 A JPS6043829 A JP S6043829A
- Authority
- JP
- Japan
- Prior art keywords
- gas
- etching
- polysilicon film
- film
- oxide 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.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
- H01L21/321—After treatment
- H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
- H01L21/32133—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only
- H01L21/32135—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by vapour etching only
- H01L21/32136—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by vapour etching only using plasmas
- H01L21/32137—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by vapour etching only using plasmas of silicon-containing layers
Abstract
Description
【発明の詳細な説明】
本発明はポリシリコン膜のドライエツチング方法に関す
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for dry etching polysilicon films.
シリコン半導体集積回路の製造，特にＭＯＳ型集積回路
の製造においては，ケ゛−１・電極材料としてポリシリ
コン膜を使用している場合が多いので。In the manufacture of silicon semiconductor integrated circuits, particularly in the manufacture of MOS type integrated circuits, polysilicon film is often used as the electrode material.
ポリシリコン膜のエツチングが非常に重要な技術になっ
ている。Etching of polysilicon films has become a very important technology.
従来，ポリシリコン膜をドライエツチングする場合，反
応性ガスとしてＣＦ４ガスを主に用いる７０ロセスは，
、Ｉ？ポリシリコン膜マスク制として使用されるホトレ
ジストの下に大きなアングカノトが入るため，パターン
の微細化が要求される超ＬＳＩの・母ターン形成におけ
るポリシリコン膜上，チング工程としては不適であった
。Conventionally, when dry etching a polysilicon film, the 70 process mainly uses CF4 gas as the reactive gas.
,I? Because a large angular drop is placed under the photoresist used as a polysilicon film mask system, it is unsuitable for use as a etch process on a polysilicon film in the formation of main turns of ultra-LSIs that require finer patterns.
これに対し，反応性ガスとして塩素を含むガス系の反応
性イオンエツチング技術により，異方性エツチング特性
が得られるようになったが，反応性ガスとして塩素を含
むガス系では、パターン精度の点や、下地の酸化膜に対
する選択比などの点で不十分な点が多かった。例えば２
反応性ガスとしてＣＣ４４ガスを主に用いるエツチング
では、ホトレノストに対する選択比が低かったり、下地
の酸化膜上に残渣を残したりしだ。又、ＣＣｔ３Ｆガス
を用いるエツチングでは、エツチングの終了後下地に多
くの残渣が残る場合があった。又、 ｃｔ２ソｔスを含
む系でのエツチングでは、 Ｃｔ２ガスの量を七分制御
しないと大きなアンダカットが入る場合がアシ、・工、
チング後にホトレジストが変形する場合も見られた。一
方、ＣＣｌ２Ｆ２がスを用いるエツチングでは、ホトレ
ノストや下地の酸化膜に対する選択比も大きく、エツチ
ング速度も速いため、他のガス系に比較して優れだエツ
チング特性を示すものの、ポリシリコン膜と下地の酸化
膜との間に大きなアンダカットが入ることが観測され、
超ＬＳＩにおけるポリシリコン膜のエツチングに使用さ
れる反応性ガスとしては、非常に使い難いことが判明し
た。On the other hand, reactive ion etching technology using a gas system containing chlorine as a reactive gas has made it possible to obtain anisotropic etching characteristics. There were many deficiencies in terms of selectivity and selectivity to the underlying oxide film. For example 2
Etching that mainly uses CC44 gas as a reactive gas has a low selectivity to photorenost and leaves residue on the underlying oxide film. Furthermore, in etching using CCt3F gas, a large amount of residue may remain on the underlying layer after etching is completed. Also, when etching in a system containing ct2 gas, large undercuts may occur unless the amount of ct2 gas is controlled.
In some cases, the photoresist was deformed after etching. On the other hand, etching using CCl2F2 gas has a high selectivity to photorenost and the underlying oxide film, and the etching rate is fast, so it shows superior etching characteristics compared to other gas systems. A large undercut was observed between the oxide film and
It has been found that it is extremely difficult to use as a reactive gas for etching polysilicon films in VLSIs.
本発明の目的は、 ｃｃｚ、２ｐ２ガスの優れたエツチ
ング特性を維持し、かつＣＣｔ２ Ｆ ２ ｇスで生じ
る特異なアンダカソトを全く生じさせない異方性エツチ
ングを行うことができるドライエツチング方法を提供す
ることにある。An object of the present invention is to provide a dry etching method capable of performing anisotropic etching that maintains the excellent etching properties of Ccz and 2P2 gases and does not produce any of the peculiar undercaching that occurs with CCt2F2 gases. It is in.
本発明は、 ＣＣ４２Ｆ２ガスにＮ２ガスを混入したガ
ス系によシトライエツチングを行うことを特徴とし。The present invention is characterized in that sittri etching is performed using a gas system in which N2 gas is mixed with CC42F2 gas.
本発明による方法を用いることにより、ポリシリコン膜
を、下地の酸化膜やホトレノストに；ｒ＝Ｊｉ、て大き
な選択比を保ちながら異方性エツチングを行うことがで
きる。By using the method according to the present invention, it is possible to perform anisotropic etching of a polysilicon film to an underlying oxide film or photorenost while maintaining a large selectivity with r=Ji.
以下２図面を参照して本発明の詳細な説明する。The present invention will be described in detail below with reference to two drawings.
第１図を参照すると、従来による反応性ガスとしてＣＣ
ｌ２Ｆ２ガスを用いて反応性イオンエツチング装置によ
シトライエツチング処理゛２施しだ場合のポリシリコン
の断面図が示されている。Referring to FIG. 1, CC is a conventional reactive gas.
A cross-sectional view of polysilicon is shown after Sitri etching treatment 2 is performed in a reactive ion etching apparatus using 12F2 gas.
第１図において、１０１はシリコンウェーハ１０２上に
成長させた厚さ数百Ｘのシリコン酸化膜１０３の上に付
着された７ｒ＠ ｌ）シリコン膜である。In FIG. 1, 101 is a 7r@l) silicon film deposited on a silicon oxide film 103 with a thickness of several hundred times, grown on a silicon wafer 102.
この被エツチング膜なるポリシリコン膜１０１土には、
エツチングマスクとしてホトレジスト１０４が塗布され
ており１反応性イオンエツチング処理が施される。この
時、第１図に示されるような。On this polysilicon film 101, which is the film to be etched,
A photoresist 104 is applied as an etching mask, and a reactive ion etching process is performed. At this time, as shown in FIG.
ポリシリコン膜１０１とシリコン酸化膜１０３の界面に
大きなアンダカノト１０５が生じる。このアンダカット
は、ＣＣｌ２Ｆ２ガスの流量に依存し。A large undercut 105 is generated at the interface between the polysilicon film 101 and the silicon oxide film 103. This undercut depends on the flow rate of CCl2F2 gas.
ＣＣｌ２Ｆ２の流量が少いとアンダカッ）：ｉ’ｉ′よ
減少する。When the flow rate of CCl2F2 is small, the undercapacitance decreases by i'i'.
しかし、 ＣＣｌ２Ｆ２ガスのみによるエツチングでは
。However, etching using CCl2F2 gas only.
この特異なアンダカッ）１０５を防ぐことは出来ない。It is not possible to prevent this peculiar undercut (105).
第２図を参照すると２本発明によるドライエツチング方
法、すなわち反応性ガスとしてＣＣ２２Ｆ２とＮ２の混
合ガスを用いて反応性イオンエツチング装置によシトラ
イエツチング処理を施しだ場合のポリシリコンの断面図
の一例が示さ九ている。Referring to FIG. 2, there is shown a cross-sectional view of polysilicon obtained by the dry etching method according to the present invention, that is, when the dry etching process is performed in a reactive ion etching apparatus using a mixed gas of CC22F2 and N2 as the reactive gas. An example is shown below.
すなわち、第２図には２シリコンウエーハ２０２上に成
長させたシリコン酸化膜２０３上の、ホトレノスＩ−２
０４をエツチングマス゛りとしたポリシリコン膜２０１
に２反応性インオンエツチング処理を施した断面が示さ
れているが２反応性ガスとしてｙ＄ｃｔ２Ｆ、、ガスに
Ｎ２がスを混合したガスによりエツチングすることによ
り’ 、、ｐす／リコ／Ｊｌｌｚｏ＋とシリコン酸化膜
２０３の界面２０５において全くアンダカットの生じな
い異方性エツチングを行うことができた。その上、ポリ
シリコン膜のエツチングが完工する丑での時間の２倍以
上のオーバーエツチングを行なっても、全くアンダカッ
トを生じない断面形状を得ることができだ。That is, in FIG.
Polysilicon film 201 using 04 as an etching mask
2 shows a cross section that has been subjected to a two-reactive in-on etching process. It was possible to perform anisotropic etching without causing any undercut at the interface 205 between Jllzo+ and the silicon oxide film 203. Moreover, even if over-etching is performed for more than twice the time taken to complete the etching of the polysilicon film, a cross-sectional shape without any undercuts can be obtained.
なお２本発明においても、ポリシリコンの異方性エツチ
ング特性を維持しながら最適エツチングを行なう為には
ガス流量比、エツチング圧力、高周波電力等を適切に設
定する必要がある。Also in the present invention, in order to perform optimal etching while maintaining the anisotropic etching characteristics of polysilicon, it is necessary to appropriately set the gas flow rate ratio, etching pressure, high frequency power, etc.
例えばＮ２ガスの混合量が少ない場合は、 ＣＣｌ２Ｆ
２ガスで得られるのと同様のアンダカノトが見られるし
、又、Ｎ２ガスの流量が多いと４？リンリコンのエツチ
ング速度が遅くなる。この為Ｎ２ガスの混合量を・ＣＣ
ｌ２Ｆ２ガスとＮ２ガスとを加えた総流量の流量比で５
％以上ないしは８０％以下の範囲に設定するのが望まし
い。For example, if the amount of N2 gas mixed is small, CCl2F
The same undertones as those obtained with 2 gas can be seen, and when the flow rate of N2 gas is high, 4? The etching speed of Lin Recon becomes slower. For this reason, the mixed amount of N2 gas is
The flow rate ratio of the total flow rate of l2F2 gas and N2 gas is 5.
It is desirable to set it within a range of % or more and 80% or less.
又、エツチング圧力があまシ低すぎるとホトレ−シスト
に対する選択比が低下して、パターンの転写精度が悪く
なる。この為エツチング圧力は４Ｐａ以上に設定するの
が望ましい。発明者等の実験結果では２本発明による最
適エツチング条件は下記に示す値であった。On the other hand, if the etching pressure is too low, the selectivity to the photoresist will be lowered, resulting in poor pattern transfer accuracy. For this reason, it is desirable to set the etching pressure to 4 Pa or higher. According to the experimental results of the inventors, the optimum etching conditions according to the present invention are as shown below.
ＣＣｔ２Ｆ２４０ＳＣＣＭ
Ｎ、２ １２８ＣＣＭ
エツチング圧力 １６Ｐａ
エツチングパワー ０．１７ Ｗ／ｃｍ２丑だこの時得
られたポリンリコンのエツチング速度は２０００Ｘ／ｍ
１ｎ以上であシ、シリコン酸化膜に対する選択比は２０
以上、ホトレノストに対しても１０以上の値が得られた
。又２本発明を用いることによシ、マスクパターンの幅
を０．１μｍ以内の差でＩリシリコン・ぐターンに転写
出来、さらにオーバーエツチングを長時同行なっても・
母ターン幅が縮少しないため、微細加工のめられる超Ｌ
ＳＩの製造プロセス、特に大量生産用のプロセスとして
適用出来る。CCt2F240SCCM N, 2 128CCM Etching pressure 16Pa Etching power 0.17 W/cm2 The etching speed of polyrecon obtained at this time was 2000X/m
Must be 1n or more, selectivity to silicon oxide film is 20
As mentioned above, a value of 10 or more was also obtained for Photorenost. Furthermore, by using the present invention, it is possible to transfer the width of the mask pattern to the silicon substrate with a difference of less than 0.1 μm, and furthermore, even if over-etching is performed for a long time,
Ultra-L, suitable for micro-machining because the width of the main turn does not shrink.
It can be applied to the SI manufacturing process, especially as a mass production process.
なお、ホトレノストの替わ９に耐エツチング膜を使用し
てもよいし、抜工、チング膜がリン、ヒ素、ボロン等を
ドーグしたポリシリコン膜であってもよいのは言うまで
もない。It goes without saying that an etching-resistant film may be used for the photorenost 9, and that the etching and etching film may be a polysilicon film doped with phosphorus, arsenic, boron, or the like.
第１図は従来による反応性ガスとしてＣＣｔ２Ｆ２ＣＣ
２Ｆ２ガスリシリコン膜をエツチングした時の・ぐター
ンの断面図２第２図は本発明による反応性ガスとしてＣ
Ｃ４２Ｆ２ガスにＮ２ガスを混合したガスを用いてポリ
シリコン膜をエツチングした時のがターンの断面図であ
る。 ・
１０１．２０１・・・ポリシリコン膜、１．０２ 。
２０２・・シリコンウェーッー１０３，２０３・・シリ
オ、
コン酸化Ｍ 、 １０４ 、２０４−≠≠）レノスト。
１０５．２０５・・・ポリシリコン膜と酸化膜の界面。Figure 1 shows CCt2F2CC as a conventional reactive gas.
2F2 gas Re-silicon film is etched.
This is a cross-sectional view of a turn when a polysilicon film is etched using a mixture of C42F2 gas and N2 gas.・101.201...Polysilicon film, 1.02. 202...Silicone 103, 203...Silio, Con oxidation M, 104, 204-≠≠) Renost. 105.205... Interface between polysilicon film and oxide film.
Claims (1)
ング膜を，導入した応答性ガスに高周波電界を印加して
発生させたプラズマ雰囲気中でドライエツチングする方
法において，上記反応性ガスとしてＣＣｌ２Ｆ３とＮ２
の混合ガスを用いることを特徴とするドライエ、チング
方法。 ２ 上記ＣＣｔ２Ｆ２とＮ２の混合ガスの〔Ｎ２ガスの
流量〕／〔ＣＣｔ２Ｆ２ガスとＮ２ガスの総流量〕が５
条以上８０％以下の範囲にある特許請求の範囲第１項記
載のドライエ、チング方法。 ３ 上記ＣＣｔ２Ｆ２とＮ２の混合ガスのエツチング圧
力が４ Ｐａ以上である特許請求の範囲第１項記載のド
ライエツチング方法。[Claims] j Polysilicon film or phosphorus or arsenic masked with photorenost. In a method of dry etching a film to be etched consisting of a polysilicon film doped with boron or the like in a plasma atmosphere generated by applying a high frequency electric field to an introduced reactive gas, CCl2F3 and N2 are used as the reactive gases.
A drying method characterized by using a mixed gas of 2 The [N2 gas flow rate]/[Total flow rate of CCt2F2 gas and N2 gas] of the above mixed gas of CCt2F2 and N2 is 5.
The drying and etching method according to claim 1, wherein the drying and etching method is in a range of not less than 80%. 3. The dry etching method according to claim 1, wherein the etching pressure of the mixed gas of CCt2F2 and N2 is 4 Pa or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15143683A JPS6043829A (en) | 1983-08-19 | 1983-08-19 | Dry etching method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15143683A JPS6043829A (en) | 1983-08-19 | 1983-08-19 | Dry etching method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6043829A true JPS6043829A (en) | 1985-03-08 |
| JPH0426209B2 JPH0426209B2 (en) | 1992-05-06 |
Family
ID=15518567
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15143683A Granted JPS6043829A (en) | 1983-08-19 | 1983-08-19 | Dry etching method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6043829A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6252932A (en) * | 1985-08-27 | 1987-03-07 | インタ−ナショナル ビジネス マシ−ンズ コ−ポレ−ション | Plasma etching |
| US5545290A (en) * | 1987-07-09 | 1996-08-13 | Texas Instruments Incorporated | Etching method |
| US6110838A (en) * | 1994-04-29 | 2000-08-29 | Texas Instruments Incorporated | Isotropic polysilicon plus nitride stripping |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58100683A (en) * | 1981-12-12 | 1983-06-15 | Nippon Telegr & Teleph Corp <Ntt> | Plasma etching method |
-
1983
- 1983-08-19 JP JP15143683A patent/JPS6043829A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58100683A (en) * | 1981-12-12 | 1983-06-15 | Nippon Telegr & Teleph Corp <Ntt> | Plasma etching method |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6252932A (en) * | 1985-08-27 | 1987-03-07 | インタ−ナショナル ビジネス マシ−ンズ コ−ポレ−ション | Plasma etching |
| US5545290A (en) * | 1987-07-09 | 1996-08-13 | Texas Instruments Incorporated | Etching method |
| US6110838A (en) * | 1994-04-29 | 2000-08-29 | Texas Instruments Incorporated | Isotropic polysilicon plus nitride stripping |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0426209B2 (en) | 1992-05-06 |
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