JP2522041B2 - Plasma etching method - Google Patents
Plasma etching methodInfo
- Publication number
- JP2522041B2 JP2522041B2 JP1102027A JP10202789A JP2522041B2 JP 2522041 B2 JP2522041 B2 JP 2522041B2 JP 1102027 A JP1102027 A JP 1102027A JP 10202789 A JP10202789 A JP 10202789A JP 2522041 B2 JP2522041 B2 JP 2522041B2
- Authority
- JP
- Japan
- Prior art keywords
- recess
- etching
- reaction gas
- flow rate
- gas
- 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
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- Drying Of Semiconductors (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、被エッチング材の凹部または開口部の側壁
に傾斜面を形成するプラズマエッチング方法に関する。TECHNICAL FIELD The present invention relates to a plasma etching method for forming an inclined surface on a sidewall of a recess or an opening of a material to be etched.
半導体圧力センサは、半導体基板の一面から深さ100
μｍ以上の凹部を掘ることにより半導体ダイアフラムを
形成し、そのダイアフラムが両側に加わる圧力差により
変形した際、ダイアフラムに形成したゲージ抵抗の抵抗
値が変化することを利用したものである。このために
は、半導体基板の一面から深さ100μｍ以上の凹部を掘
らなければならない。この凹部の形成には、従来は、例
えばストップエッチングを利用したウェットエッチング
法が用いられていたが、後工程での便宜のために側壁に
適切な傾斜面をもつ凹部を形成するためプラズマエッチ
ング法の採用が検討されている。プラズマエッチング法
は、例えば特公昭63−45469号公報に記載されているよ
うに単結晶シリコン板上に積層された多結晶シリコン層
に傾斜した側壁を有するパターンを形成するときにも用
いられる。傾斜した側壁を形成するには異方性エッチン
グを行うことが必要である。第１図は異方性エッチング
に用いられるプラズマエッチング装置を示し、反応槽１
の中には対向して上部電極２と下部電極３が配置され、
下部電極３上に被エッチング材が載せられる。上部電極
は絶縁物５を介して反応槽１外に引出され、ブロッキン
グコンデンサ６を介して高周波電源７に接続されてい
る。反応槽１には流量調整器81を備えた反応ガス導入管
８と排気管９が開口している。反応槽１を排気管９から
排気しながら、導入管８より反応ガス10を導入し、両電
極2,3間に高周波電源７からの高周波電力を印加して反
応ガス10をプラズマ化する。異方性エッチングを行うた
めには、反応ガスの組成，電力，槽内圧力の条件を調整
するか、被エッチング材の不純物濃度に勾配をつける。
被エッチング材のエッチング防止用のマスク材を被着し
ない部分が異方性エッチングされることにより、エッチ
ングにより生ずる凹部または開口部の側壁の傾斜面が生
ずる。The semiconductor pressure sensor has a depth of 100
This is because a semiconductor diaphragm is formed by digging a recess of μm or more, and when the diaphragm is deformed by the pressure difference applied to both sides, the resistance value of the gauge resistance formed in the diaphragm changes. For this purpose, a recess having a depth of 100 μm or more must be dug from one surface of the semiconductor substrate. Conventionally, for example, a wet etching method using stop etching has been used to form the concave portion, but a plasma etching method is used to form the concave portion having an appropriate inclined surface on the side wall for convenience of a later step. Is being considered for adoption. The plasma etching method is also used, for example, when forming a pattern having inclined sidewalls on a polycrystalline silicon layer laminated on a single crystal silicon plate as described in JP-B-63-45469. Anisotropic etching is required to form sloped sidewalls. FIG. 1 shows a plasma etching apparatus used for anisotropic etching.
An upper electrode 2 and a lower electrode 3 are arranged to face each other,
The material to be etched is placed on the lower electrode 3. The upper electrode is drawn out of the reaction tank 1 via an insulator 5 and is connected to a high frequency power source 7 via a blocking capacitor 6. The reaction tank 1 is provided with a reaction gas introduction pipe 8 provided with a flow rate controller 81 and an exhaust pipe 9. While evacuating the reaction tank 1 through the exhaust pipe 9, the reaction gas 10 is introduced through the introduction pipe 8 and the high frequency power from the high frequency power source 7 is applied between the electrodes 2 and 3 to turn the reaction gas 10 into plasma. In order to carry out anisotropic etching, the conditions of the composition of the reaction gas, the power, and the pressure in the tank are adjusted, or the impurity concentration of the material to be etched is graded.
By anisotropically etching the portion of the material to be etched that is not coated with the mask material for preventing etching, an inclined surface of the side wall of the recess or opening is formed due to the etching.
表面にエッチング防止用のマスク材を被着した被エッ
チング材にエッチングにより生ずる凹部または開口部の
側壁が傾斜面となるように加工する際、傾斜面の傾斜角
度を変えようとするときには、改めて反応ガスの成分ガ
ス混合比や圧力を調節し直し、エッチング条件を新たに
定める必要性がある。被エッチング材に生ずる凹部また
は開口部の側壁の傾斜角度は、エッチング後の被エッチ
ング材の機械的な特性，被エッチング材の表面を被覆す
る薄膜の付着性あるいは凹部に埋込まれる半導体層の電
気的特性などにより任意の値にし得ることが望ましい。
しかし、上記のように側壁の傾斜角度を変更するのは容
易でなかった。When etching the material to be etched with a mask material for etching prevention so that the side wall of the recess or opening caused by etching becomes an inclined surface, when reacting when changing the inclination angle of the inclined surface, a new reaction occurs. It is necessary to readjust the etching conditions by adjusting the gas mixture ratios and pressures of the gases again. The inclination angle of the side wall of the recess or opening formed in the material to be etched depends on the mechanical characteristics of the material to be etched after etching, the adhesiveness of the thin film covering the surface of the material to be etched, or the electrical property of the semiconductor layer embedded in the recess. It is desirable that it can be set to an arbitrary value depending on the physical characteristics.
However, it was not easy to change the inclination angle of the side wall as described above.
本発明の目的は、上記の問題を解決し、被エッチング
材に形成される凹部あるいは開口部の側壁の傾斜角度を
容易に変えることができるプラズマエッチング方法を提
供することを目的とする。An object of the present invention is to solve the above problems and to provide a plasma etching method capable of easily changing the inclination angle of the sidewall of the recess or opening formed in the material to be etched.
上記の目的を達成するために、本発明は、対向する電
極間に電圧を印加し、電極間に存在する酸素を含む減圧
反応ガス中にプラズマを発生させ、一方の電極近傍に配
置され、表面にマスク材のパターンを有する半導体基板
のマスクで覆われない部分をエッチングして深さ100μ
ｍ以上の凹部あるいは開口部を形成する際に、反応ガス
中の酸素ガスの混合比を一定に保ちながら反応ガスの総
流量だけを調整することにより、エッチングにより生ず
る凹部あるいは開口部の側壁の傾斜形状を変化させるも
のとする。In order to achieve the above-mentioned object, the present invention applies a voltage between opposing electrodes to generate plasma in a reduced pressure reaction gas containing oxygen existing between the electrodes, and the plasma is generated in the vicinity of one of the electrodes. The semiconductor substrate that has the pattern of the mask material is etched to a depth of 100μ
When forming a recess or an opening of m or more, by adjusting only the total flow rate of the reaction gas while keeping the mixing ratio of oxygen gas in the reaction gas constant, the inclination of the sidewall of the recess or the opening caused by etching The shape shall be changed.
酸素を含む反応ガスの酸素ガス混合比を一定に保ちな
がら総流量を変えると、酸素ガスの量が変わる。エッチ
ング反応は、反応ガス中の酸素のラジカル量により左右
され、反応ガスの総流量を増加させれば、酸素のラジカ
ル過多の状態となって形成される凹部あるいは開口部の
側壁の傾斜角度は小さくなる。総流量を減らすと酸素ラ
ジカルの量が減り、側壁は立って垂直に近くなる。さら
に総流量を減らして酸素ラジカルの量を減らすと、傾斜
角度がさらにふえ、凹部あるいは開口部の側壁は下方の
開いた形状になる。このように総流量を増減させても、
反応ガスの成分ガスの混合比が同じであればプラズマ発
生条件をその都度変化させる必要がなく、傾斜角度の制
御が容易にできる。When the total flow rate is changed while keeping the oxygen gas mixture ratio of the reaction gas containing oxygen constant, the amount of oxygen gas changes. The etching reaction depends on the amount of oxygen radicals in the reaction gas, and if the total flow rate of the reaction gas is increased, the inclination angle of the side wall of the recess or opening formed in the state of excessive oxygen radicals becomes small. Become. When the total flow rate is reduced, the amount of oxygen radicals is reduced, and the side wall becomes upright and nearly vertical. When the total flow rate is further reduced to reduce the amount of oxygen radicals, the inclination angle is further increased, and the side wall of the recess or opening has a downward open shape. Even if the total flow rate is increased or decreased in this way,
If the mixing ratio of the component gases of the reaction gas is the same, it is not necessary to change the plasma generation condition each time, and the tilt angle can be easily controlled.
第１図に示した装置を用い、下部電極３の上にシリコ
ン酸化膜のマスクを設けたシリコン基板４を置き、上部
電極２と下部電極３との間隔を50mmとし、排気管９から
真空排気すると共に、導入管８よりO2ガスとSF6ガスと
を混合した反応ガス10を導入し、槽内圧力を0.4Torrに
保ち、上，下電極2,3間に高周波電源７により150Wの高
周波電力を供給し、プラズマを発生させた。O2ガスの流
量を10SCCM,SF6ガスの流量を23.3SCCM、すなわちO2ガス
混合比を30％にしたとき、O2ラジカルの消費効率がよ
く、第２図（ａ）に示したようにシリコン基板４に垂直
に立つ側壁をもつ凹部11が形成された。反応ガスの混合
比を変えないで、O2ガスの流量を20SCCM、総流量を66.7
SCCMとしたときには、O2ラジカルが過多の状態になり、
第２図（ｂ）に示したように上方に開いた側壁をもつ凹
部12が形成された。反応ガスの混合比を変えないで、O2
ガスの流量5SCCM、総流量16.7SCCMとしたときには、O2
ラジカルが不足の状態になり、第２図（ｃ）に示すよう
に底部の方が開いた凹部13が形成された。総流量以外の
プラズマ発生条件は変える必要はなかった。なお、槽内
の圧力は、総流量を変えても排気系のバルブの開閉度を
変える装置を用いることにより、数秒の間に圧力を一定
圧力域内に落ちつかせることができた。Using the apparatus shown in FIG. 1, a silicon substrate 4 provided with a mask of a silicon oxide film is placed on the lower electrode 3, the distance between the upper electrode 2 and the lower electrode 3 is set to 50 mm, and the exhaust pipe 9 is evacuated. In addition, the reaction gas 10 in which O 2 gas and SF 6 gas were mixed was introduced from the introduction pipe 8, the pressure in the tank was maintained at 0.4 Torr, and a high frequency power of 150 W was generated by the high frequency power supply 7 between the upper and lower electrodes 2 and 3. Electric power was supplied to generate plasma. When the flow rate of O 2 gas was 10 SCCM and the flow rate of SF 6 gas was 23.3 SCCM, that is, when the O 2 gas mixture ratio was 30%, the consumption efficiency of O 2 radicals was good, and as shown in FIG. 2 (a). A recess 11 having a side wall standing perpendicular to the silicon substrate 4 was formed. The flow rate of O 2 gas is 20 SCCM and the total flow rate is 66.7 without changing the mixing ratio of the reaction gas.
When using SCCM, O 2 radicals are in excess,
As shown in FIG. 2 (b), a recess 12 having a side wall opened upward was formed. O 2 without changing the mixing ratio of the reaction gas
When the gas flow rate is 5 SCCM and the total flow rate is 16.7 SCCM, O 2
Radicals became insufficient, and a recess 13 having an open bottom was formed as shown in FIG. 2 (c). It was not necessary to change the plasma generation conditions other than the total flow rate. The pressure inside the tank could be kept within a certain pressure range within a few seconds by using a device that changes the opening / closing degree of the exhaust system valve even if the total flow rate is changed.
本発明によれば、酸素ガスの混合比を変えなくても、
反応ガスの総流量を変えることによりプラズマ中の酸素
ラジカルの量を変化させることができ、それによってプ
ラズマの発生条件を一定に保持したまま、半導体基体に
エッチングで形成される凹部あるいは開口部の側壁の傾
斜角度を調整することが可能になった。従って、凹部あ
るいは開口部の形状の制御が容易となり、任意の機械的
特性をもつ基体の作成，後工程での薄膜付着性の向上あ
るいは新しい形状の埋込素子の作成など種々の分野に有
効に適用することができる。According to the present invention, without changing the mixing ratio of oxygen gas,
By changing the total flow rate of the reaction gas, the amount of oxygen radicals in the plasma can be changed, whereby the side wall of the recess or opening formed in the semiconductor substrate by etching while keeping the plasma generation conditions constant. It is now possible to adjust the tilt angle of the. Therefore, it becomes easy to control the shape of the recess or opening, and it is effective in various fields such as the production of a substrate having arbitrary mechanical characteristics, the improvement of the thin film adhesion in the post process, or the production of an embedded element of a new shape. Can be applied.
第１図は本発明の実施に用いられるプラズマエッチング
装置の一例の断面図、第２図（ａ），（ｂ），（ｃ）は
本発明の一実施例によって形成される凹部の形状を示す
断面図である。 1:反応槽、2:上部電極、3:下部電極、4:シリコン基板、
7:高周波電源、8:ガス導入管、9:排気管、10:反応ガ
ス、11,12,13:凹部。FIG. 1 is a sectional view of an example of a plasma etching apparatus used for carrying out the present invention, and FIGS. 2 (a), (b) and (c) show the shape of a recess formed by the embodiment of the present invention. FIG. 1: Reactor, 2: Upper electrode, 3: Lower electrode, 4: Silicon substrate,
7: high frequency power supply, 8: gas introduction pipe, 9: exhaust pipe, 10: reaction gas, 11, 12, 13: recessed portion.
Claims (1)
存在する酸素を含む減圧反応ガス中にプラズマを発生さ
せ、一方の電極近傍に配置され、表面にマスク材のパタ
ーンを有する半導体基板のマスクで覆われない部分をエ
ッチングして、深さ100μｍ以上の凹部あるいは開口部
を形成する際に、反応ガス中の酸素ガスの混合比を一定
に保ちながら反応ガスの総流量だけを調整することによ
り、エッチングにより生ずる凹部あるいは開口部の側壁
の傾斜形状を変化させることを特徴とするプラズマエッ
チング方法。1. A semiconductor having a pattern of a mask material on the surface, which is arranged in the vicinity of one of the electrodes by applying a voltage between the electrodes facing each other to generate plasma in a reduced pressure reaction gas containing oxygen existing between the electrodes. When etching a portion of the substrate that is not covered by the mask to form a recess or opening with a depth of 100 μm or more, adjust only the total flow rate of the reaction gas while keeping the mixing ratio of oxygen gas in the reaction gas constant. The plasma etching method is characterized in that the inclined shape of the side wall of the recess or the opening caused by the etching is changed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1102027A JP2522041B2 (en) | 1989-04-21 | 1989-04-21 | Plasma etching method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1102027A JP2522041B2 (en) | 1989-04-21 | 1989-04-21 | Plasma etching method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02280323A JPH02280323A (en) | 1990-11-16 |
| JP2522041B2 true JP2522041B2 (en) | 1996-08-07 |
Family
ID=14316274
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1102027A Expired - Lifetime JP2522041B2 (en) | 1989-04-21 | 1989-04-21 | Plasma etching method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2522041B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5094702A (en) * | 1989-06-19 | 1992-03-10 | U.S. Dept. Of Energy | Menu driven heat treatment control of thin walled bodies |
| WO2000041228A1 (en) | 1998-12-28 | 2000-07-13 | Tokyo Electron Yamanashi Limited | Method of plasma processing |
| US7135410B2 (en) * | 2003-09-26 | 2006-11-14 | Lam Research Corporation | Etch with ramping |
| US20060071270A1 (en) * | 2004-09-29 | 2006-04-06 | Shibib Muhammed A | Metal-oxide-semiconductor device having trenched diffusion region and method of forming same |
| CN113972135A (en) * | 2020-07-24 | 2022-01-25 | 和舰芯片制造(苏州)股份有限公司 | Etching method of Y-type deep groove and manufacturing method of deep groove isolation structure |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59119763A (en) * | 1982-12-25 | 1984-07-11 | Agency Of Ind Science & Technol | Formation of thin film metal insulator semiconductor transistor |
| JPS60102745A (en) * | 1983-11-09 | 1985-06-06 | Mitsubishi Electric Corp | Manufacture of semiconductor device |
-
1989
- 1989-04-21 JP JP1102027A patent/JP2522041B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02280323A (en) | 1990-11-16 |
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