JPH022130A - Method and device for forming silicon thermal oxide film - Google Patents
Method and device for forming silicon thermal oxide filmInfo
- Publication number
- JPH022130A JPH022130A JP14644688A JP14644688A JPH022130A JP H022130 A JPH022130 A JP H022130A JP 14644688 A JP14644688 A JP 14644688A JP 14644688 A JP14644688 A JP 14644688A JP H022130 A JPH022130 A JP H022130A
- Authority
- JP
- Japan
- Prior art keywords
- oxide film
- washed
- wafer
- reactor
- torr
- 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.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 20
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 16
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 16
- 239000010703 silicon Substances 0.000 title claims abstract description 16
- 230000003647 oxidation Effects 0.000 claims abstract description 19
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 19
- 238000004140 cleaning Methods 0.000 claims description 11
- 239000000758 substrate Substances 0.000 claims description 6
- 230000001590 oxidative effect Effects 0.000 claims description 2
- 229910001868 water Inorganic materials 0.000 abstract description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 12
- 238000006243 chemical reaction Methods 0.000 abstract description 10
- 239000012535 impurity Substances 0.000 abstract description 9
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 abstract description 7
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 abstract description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract description 4
- 239000000203 mixture Substances 0.000 abstract description 4
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 abstract description 3
- 235000011114 ammonium hydroxide Nutrition 0.000 abstract description 3
- 238000007599 discharging Methods 0.000 abstract 1
- 239000007788 liquid Substances 0.000 abstract 1
- 229910052814 silicon oxide Inorganic materials 0.000 abstract 1
- 238000005406 washing Methods 0.000 abstract 1
- 238000010438 heat treatment Methods 0.000 description 17
- 239000007789 gas Substances 0.000 description 13
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 8
- 239000001301 oxygen Substances 0.000 description 8
- 229910052760 oxygen Inorganic materials 0.000 description 8
- 235000012431 wafers Nutrition 0.000 description 8
- 230000000694 effects Effects 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000010453 quartz Substances 0.000 description 3
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- PZPGRFITIJYNEJ-UHFFFAOYSA-N disilane Chemical compound [SiH3][SiH3] PZPGRFITIJYNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 229910000077 silane Inorganic materials 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- KALNIDZIJNJFPI-UHFFFAOYSA-N gold hydrofluoride Chemical compound F.[Au] KALNIDZIJNJFPI-UHFFFAOYSA-N 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000004949 mass spectrometry 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
- 239000007800 oxidant agent Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は、半導体集積回路をはじめとする各種固体デバ
イスに用いられる、シリコン熱酸化膜の形成方法および
形成装置に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method and apparatus for forming a silicon thermal oxide film used in various solid-state devices including semiconductor integrated circuits.
［従来の技術］
従来半導体集積回路などに用いられるシリコンの熱酸化
膜は１次の様な方法で形成されてきた。[Prior Art] Conventionally, silicon thermal oxide films used in semiconductor integrated circuits and the like have been formed using a primary method.
すなわち、シリコン基板を洗浄後石英製のテートに基板
を載せ、電気炉で加熱された開管式石英反応管中で所定
の温度および所定の雰囲気（酸素あるいは水蒸気雰囲気
などり下で加熱する。ここで洗浄方法としては、過酸化
水素水／アンモニア水混液（例えばＨ２Ｏ２：ＮＨ４Ｏ
Ｈ：Ｈ２Ｏ＝ １ ： １ ： ５ ）、あるいは過酸
化水素水／塩酸混液（例えばＨ２０□：ＨＣｔ：Ｈ２０
＝１：１：５）、あるいは硫酸／水混液（例えばＨ２Ｓ
Ｏ４：Ｈ２Ｏ：１：４）などが代表的なものであるが、
これらの洗浄液は酸化剤を使用しているため、洗浄後薄
い酸化膜（以後洗浄酸化膜と呼ぶ）がシリコン基板表面
上に形成される。洗浄酸化膜を避けるため、洗浄後希弗
酸中でエツチングしたとしても、シリコン基板表面は大
気中の酸素や水蒸気によって１ ｎｍ程度の酸化膜がす
みやかに形成されてしまう（以後、自然酸化膜と呼ぶ）
。従って、目的とする酸化工程は、ウェー７１表面に初
期酸化膜（洗浄酸化膜、あるいは自然酸化膜）が存在す
る状態を出発点とし、熱酸化が行われることに、なる。That is, after cleaning the silicon substrate, the substrate is placed on a quartz tray and heated at a predetermined temperature and under a predetermined atmosphere (such as an oxygen or water vapor atmosphere) in an open-tube quartz reaction tube heated in an electric furnace. The cleaning method is a hydrogen peroxide/ammonia water mixture (for example, H2O2:NH4O).
H:H2O=1:1:5), or a mixture of hydrogen peroxide/hydrochloric acid (for example, H20□:HCt:H20
= 1:1:5), or a sulfuric acid/water mixture (e.g. H2S
Typical examples include O4:H2O:1:4),
Since these cleaning solutions use an oxidizing agent, a thin oxide film (hereinafter referred to as a cleaning oxide film) is formed on the surface of the silicon substrate after cleaning. Even if etching is performed in dilute hydrofluoric acid after cleaning to avoid a cleaning oxide film, an oxide film of about 1 nm will quickly form on the silicon substrate surface due to oxygen and water vapor in the atmosphere (hereinafter referred to as a natural oxide film). call)
. Therefore, the intended oxidation process starts from a state where an initial oxide film (cleaned oxide film or natural oxide film) exists on the surface of the wafer 71, and thermal oxidation is performed.
初期酸化膜の影響は、工ぎタキシャル成長の分野では従
来から強く認識され、成長前に初期酸化膜を除去する工
程が必ず入れられている。水素ガス中で高温熱処理する
、あるいは高真空中で熱処理する工程などがそれに相当
する。しかし熱酸化の分野では、初期酸化膜の重要性は
従来まりたく考慮されておらず、上述したように初期酸
化膜が存在する状態から熱酸化を行ってきたと同時に、
初期酸化膜を除去可能な酸化膜形成装置は存在しなかっ
た。初期酸化膜は、先に述べた熱処理をしない限り蒸発
することなく膜中に残存し、従って酸化条件は所望の熱
酸化条件からかけ離れてしまう。つまり、低温酸化膜を
取り込んだ酸化膜となってしまうことが避けられない。The influence of the initial oxide film has been strongly recognized in the field of engineered taxial growth, and a step to remove the initial oxide film is always included before growth. This includes processes such as high-temperature heat treatment in hydrogen gas or heat treatment in high vacuum. However, in the field of thermal oxidation, the importance of the initial oxide film has not been considered at all, and as mentioned above, thermal oxidation has been performed from the state where the initial oxide film exists.
There was no oxide film forming apparatus that could remove the initial oxide film. The initial oxide film remains in the film without being evaporated unless the heat treatment described above is performed, and therefore the oxidation conditions are far from the desired thermal oxidation conditions. In other words, it is inevitable that the resulting oxide film will contain a low-temperature oxide film.
初期酸化膜の影響は酸化膜厚が薄いほど著しく、デ１４
イスの微細化が進展し５ ｎｍ以下の酸化膜がダート酸
化膜として要求されてくると、影響が無視できなくなる
。The effect of the initial oxide film is more pronounced as the oxide film becomes thinner, and
As device miniaturization progresses and oxide films of 5 nm or less are required as dirt oxide films, the effects cannot be ignored.
その理由は、低温酸化膜は高温で熱処理を受けたとして
も膜質の改善に限界がメリ、高温で熱酸化した酸化膜に
及ばないため（加納、張、版部、小出、松材：電子情報
通信学会技術研究報告ＳＤＭ８７−１７３〜１８１（１
９８１）２５参照）、また洗浄酸化膜あるいは自然酸化
膜には、不純物が取り込まれている可能性や吸着してい
る可能性が犬きく、酸化膜中の不純物となって膜質を劣
化させる原因となるためである。従って新しい酸化膜形
成方法およびそれを可能とする酸化膜形成装置が必要と
なる。The reason for this is that even if a low-temperature oxide film is heat-treated at a high temperature, there is a limit to the improvement in film quality, and it is not as good as an oxide film thermally oxidized at a high temperature (Kano, Zhang, Hanbe, Koide, Matsuzai: Electronics Institute of Information and Communication Engineers Technical Research Report SDM87-173~181 (1
(Refer to 981)25), there is a possibility that impurities may be taken in or adsorbed to the cleaned oxide film or the natural oxide film, and they may become impurities in the oxide film and cause deterioration of the film quality. This is to become. Therefore, a new oxide film forming method and an oxide film forming apparatus that enables the method are required.
［発明が解決し↓うとする課題］
本発明は上記の事情に鑑みてなされたもので、悪影響の
元となる初期酸化膜を除去し、初期酸化膜のない状態を
出発点として、所定の温度および雰囲気のもとて良質の
酸化膜を形成し得るシリコン熱酸化膜形成方法および形
成装置を提供することを目的とする。[Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances. It is an object of the present invention to provide a silicon thermal oxide film forming method and a forming apparatus capable of forming a high-quality oxide film in a suitable atmosphere.
［課題を解決するだめの手段と作用コ
本発明は上記目的を達成するために、シリコン基板表面
の自然酸化膜あるいは洗浄で形成された酸化膜を除去す
る工程と、その後大気中に取シ出すことなく、所定の温
度および雰囲気ｆｆｘ中で熱酸化する工程とから構成さ
れていることを特徴とするものであシ、また、反応炉と
それを加熱する電気炉、および反応炉中へのガス供給シ
ステム、およびｌＸ１０Ｔｏｒｒ以下に排気可能なガス
排気システム、および反応炉との間に／Ｊルブを設けた
予備排気室、および予備排気室から反応炉へシリコンウ
ェーハを出し入れ可能とする搬送システムから成り１反
応炉中で熱酸化前処理と熱酸化を連続的に行うことを特
徴とするものであり、初期酸化膜のない状態を出発点と
して、所定の温度および雰囲気のもとて良質の酸化膜を
形成するようにしたものである。[Means and operations for solving the problem] In order to achieve the above object, the present invention includes a step of removing a natural oxide film or an oxide film formed by cleaning on the surface of a silicon substrate, and then taking it out into the atmosphere. It is characterized by comprising a step of thermal oxidation at a predetermined temperature and atmosphere ffx without any heat, and also includes a reaction furnace, an electric furnace for heating it, and a gas flow into the reaction furnace. It consists of a supply system, a gas exhaust system capable of exhausting to 10 Torr or less, a preliminary exhaust chamber with a J-lube installed between it and the reactor, and a transfer system that allows silicon wafers to be taken in and out of the reaction chamber from the preliminary exhaust chamber. It is characterized by performing thermal oxidation pretreatment and thermal oxidation continuously in one reactor, starting from a state with no initial oxide film, and forming a very high quality oxide film at a specified temperature and atmosphere. It is designed to form a .
［実施例］
第１図に、本発明の一実施例による装置の概略図を示す
。本装置の主な構成は、反応炉１ノとそれを加熱する電
気炉１２．、／ｌ／ス供給システム１３゜ガス排気シス
テム１４．予備排気室１５．ウェーハ搬送システム１６
．））”−トバルプ１７である。[Embodiment] FIG. 1 shows a schematic diagram of an apparatus according to an embodiment of the present invention. The main components of this device are a reactor 1 and an electric furnace 12 for heating it. ,/l/s supply system 13° gas exhaust system 14. Pre-exhaust chamber 15. Wafer transport system 16
．． ))”-Tbarp 17.
反応炉１１は、高温に加熱した時放出ガスが少ない材料
、例えば石英で構成され、電気炉１２は、反応炉１ノの
温度が空間的時間的に一定に保たれる方法、例えば抵抗
加熱ヒータで構成される。この場合急熱急冷できる電気
炉の方が好ましい。他の加熱方法、例えば傍熱型赤外線
加熱なども可能であるが、均一性安定性が要求される熱
酸化膜では、抵抗加熱が最も優れる。ガス供給システム
１３は、ガスボンベや減圧弁、各種バルブや流量計など
から構成される。ガス排気システム１４は、例えば三系
統から構成する。一系統は反応炉１１をＩ Ｘ １０−
２Ｔｏｒｒ以下に排気できるように、例えばター′Ｎポ
ンプなどを使用する。この場合、反応炉１１の熱により
ポンプの能力が劣化しないようにすることが重要で、ポ
ンプの排気口が反応炉１１を直接見込まないように例え
ば９０度曲げて設置する必要がある。二番目の系統は大
気圧〜１０−２Ｔｏｒｒに対応できるように、例えばロ
ータリポンプとメカニカルブースターポンプあるいはド
ライポンプなどを使用し、反応炉１１との間に圧力調整
用の弁を設ける。三番目の系統は大気圧での使用に対応
できるようにするため、反応炉１゛１の後部に弁を設は
ガスを直接ドレイン（大気圧）に流せるようにする７、
予備排気室１５と反応炉１ノの間にはゲートバルブ１７
を設け、反応室を高真空に保つ。The reactor 11 is made of a material that releases little gas when heated to a high temperature, such as quartz, and the electric furnace 12 is made of a material that releases less gas when heated to a high temperature, and the electric furnace 12 is made of a material that keeps the temperature of the reactor 1 constant in space and time, such as a resistance heater. Consists of. In this case, an electric furnace capable of rapid heating and cooling is preferable. Although other heating methods, such as indirect infrared heating, are possible, resistance heating is most suitable for thermal oxide films that require uniformity and stability. The gas supply system 13 includes a gas cylinder, a pressure reducing valve, various valves, a flow meter, and the like. The gas exhaust system 14 includes, for example, three systems. One system has reactor 11 as I x 10-
For example, a ter-N pump is used so that the pressure can be evacuated to 2 Torr or less. In this case, it is important to prevent the performance of the pump from deteriorating due to the heat of the reactor 11, and it is necessary to bend the pump by 90 degrees, for example, so that the exhaust port of the pump does not directly look into the reactor 11. The second system uses, for example, a rotary pump, a mechanical booster pump, or a dry pump, and is provided with a pressure regulating valve between it and the reactor 11 so as to be able to cope with atmospheric pressure to 10 -2 Torr. In order to make the third system compatible with use at atmospheric pressure, a valve is installed at the rear of the reactor 1゛1 to allow gas to flow directly to the drain (atmospheric pressure)7.
A gate valve 17 is installed between the preliminary exhaust chamber 15 and the reactor 1.
and maintain the reaction chamber at high vacuum.
続いて本実施例の装置を用いて、高真空下で熱処理する
ことによって初期酸化膜を除去する方法の一例について
説明する。シリコンウェーハを■（２０２（３０％）
：ＮＨ４ＯＨ（２９％）：Ｈ２０＝１：１：５中で煮沸
洗浄し、水洗後金弗酸（ＨＦ（５０％）：Ｈ２Ｏ＝３：
１００）中で洗浄酸化膜をエツチングする。その後Ｈ２
Ｏ２（３０チ）：ＨＣＡ（３６％）：Ｈ２Ｏ＝ １ ：
１：５中で煮沸洗浄し、水洗、乾燥させ、予備排気室
１５ヘウエーハを設置する。予備排気室１５をＩ Ｘ
１０ Ｔｏｒｒまで排気した後ダートバルブ１７を開
け、例えばＩ Ｘ １０ Ｔｏｒｒ 、 ５００℃に
設定した反応炉・１１の中にウェーハを搬送する。反応
炉１１の圧力は一時低下するが、ダートバルブ１７を閉
じると数分で元に戻る。Next, an example of a method for removing the initial oxide film by heat treatment under high vacuum using the apparatus of this embodiment will be described. ■ Silicon wafer (202 (30%)
: NH4OH (29%): H20 = 1:1:5 and washed with water, then gold hydrofluoric acid (HF (50%): H2O = 3:
100) to etch the cleaned oxide film. Then H2
O2 (30 cm): HCA (36%): H2O = 1:
The wafer is washed by boiling in a 1:5 medium, washed with water, dried, and placed in a preliminary exhaust chamber 15. Pre-exhaust chamber 15 I
After evacuation to 10 Torr, the dart valve 17 is opened, and the wafer is transferred into a reactor 11 set at, for example, I x 10 Torr and 500°C. The pressure in the reactor 11 decreases temporarily, but returns to normal within a few minutes when the dart valve 17 is closed.
その後反応炉１ノを８００℃に昇温し、例えば真空度Ｉ
Ｘ １０”” Ｔｏｒｒのもとて１０分間加熱する。Thereafter, the temperature of the reactor 1 is raised to 800°C, and the vacuum degree is
Heat for 10 minutes at 10" Torr.
、この真空度は全圧力であシ、マススペクトルによる測
定では、水蒸気の分圧はその１０〜２０％程度、酸素は
はとんど検出されない。以上の条件下の熱処理によって
、初期酸化膜は確実に除去される。同時に膜中あるいは
表面に吸着していた不純物原子も除去される。洗浄後希
弗酸で処理した場合には、よシ短時間で酸化膜除去が可
能である。The degree of vacuum is the total pressure, and when measured by mass spectrometry, the partial pressure of water vapor is about 10 to 20% of that, and oxygen is hardly detected. The initial oxide film is reliably removed by the heat treatment under the above conditions. At the same time, impurity atoms adsorbed in the film or on the surface are also removed. When treated with dilute hydrofluoric acid after cleaning, the oxide film can be removed in a much shorter time.
しかる後反応炉１ノの温度を所望の値にし、所望の雰囲
気を導入し所望の圧力で熱酸化する。例えば、第三の排
気系統を用いて乾燥酸素ｌ ａｔｍ中で８００℃、４０
分間熱処理すれば、（１００）面では４０Ａの洗浄酸化
膜が形成される。酸素を導入した時にウェーハ温度が変
化し酸化膜厚の制御性に影響を与えるが、酸化時間を２
０分程度以上にすれば無視できる。このようにして形成
した熱酸化膜は、初期酸化膜のような低温酸化膜を含ん
でおらず、シリコン界面から表面まで所望の温度と雰囲
気で形成された酸化膜である。さらに、初期酸化膜に含
まれる不純物原子の取シ込みがまったくないため、耐圧
や歩留まシの向上が図られる。Thereafter, the temperature of the reactor 1 is set to a desired value, a desired atmosphere is introduced, and thermal oxidation is carried out at a desired pressure. For example, at 800 °C and 40
After a minute of heat treatment, a 40A cleaning oxide film is formed on the (100) plane. The wafer temperature changes when oxygen is introduced, which affects the controllability of the oxide film thickness, but the oxidation time is
It can be ignored if it is set to about 0 minutes or more. The thermal oxide film thus formed does not include a low-temperature oxide film like the initial oxide film, but is an oxide film formed from the silicon interface to the surface at a desired temperature and atmosphere. Furthermore, since no impurity atoms contained in the initial oxide film are taken in, breakdown voltage and yield can be improved.
なお初期酸化膜が除去される条件の確認は、エピタキシ
ャル膜堆積した試料を作成し、Ｓ ＩＭＳ（Ｓｓｃｏｎ
ｄａｒｙ Ｉｏｎ Ｍｌｃｒｏ ５ｐｅｃｔｒｏｓｃｏ
ｐｙ）分析によって行った。To confirm the conditions under which the initial oxide film is removed, prepare a sample with an epitaxial film deposited and perform SIMS (Sscon
dary Ion Mlcro 5pectrosco
py) analysis.
以上に代表的な例を挙げたが、真空中熱処理によって初
期酸化膜が除去されるかどうかは、第２図に示したよう
に熱処理時の真空度によって決定され、ある圧力以下で
ないと酸化膜は除去されない。Although typical examples have been given above, whether or not the initial oxide film is removed by heat treatment in vacuum is determined by the degree of vacuum during heat treatment, as shown in Figure 2. is not removed.
例えば、Ｉ Ｘ １０−８Ｔｏｒｒのもとでは、７５０
〜９００℃、１０分の熱処理で実際に十分除去されてお
シ、この事実は、酸化膜除去工程と酸化工程とを同じ温
度で行える範囲が広いことを意味している＠ｌＸｌ０
Ｔｏｒｒでは除去不可能であった。For example, under I x 10-8 Torr, 750
In fact, heat treatment at ~900°C for 10 minutes was enough to remove the oxide film, and this fact means that there is a wide range in which the oxide film removal process and the oxidation process can be performed at the same temperature.
It could not be removed with Torr.
このように初期酸化膜除去時における真空度の影響は太
きいため、予め反応室は高温で十分焼きだしを行い（８
００℃熱酸化の場合９００℃、１ｈｒ）高真空状態を維
持しておく必要がある。このためには、反応炉１１との
間にバルブＪ７を設けた予備排気室１５は必須である。In this way, the degree of vacuum has a large effect on the initial oxide film removal, so the reaction chamber was sufficiently baked out at a high temperature (8
In the case of thermal oxidation at 00°C, it is necessary to maintain a high vacuum state at 900°C for 1 hr. For this purpose, a preliminary exhaust chamber 15 provided with a valve J7 between the reactor 11 and the reactor 11 is essential.
ここでは酸化雰囲気として乾燥酸素の例を挙げたが、水
蒸気、酸素十三弗化窒素、酸素＋塩化水素、酸素＋トリ
クレンなど所望の雰囲気を選んでもよいのは勿論である
。Here, an example of dry oxygen is given as the oxidizing atmosphere, but it goes without saying that any desired atmosphere such as water vapor, oxygen/nitrogen trifluoride, oxygen + hydrogen chloride, oxygen + trichlene, etc. may be selected.
初期酸化膜の他の除去方法としては、水素雰囲気中で高
温に加熱する方法、シランあるいはジシランを流して加
熱する方法を用いることも可能である。水素ガス中では
酸化膜のエツチング速度が遅いので、実質的に１０００
℃以上の高温が必要であり、高温を避けたい場合には使
用できない。As other methods for removing the initial oxide film, it is also possible to use a method of heating to a high temperature in a hydrogen atmosphere or a method of heating by flowing silane or disilane. Since the etching rate of the oxide film is slow in hydrogen gas, it is practically
It requires a high temperature of ℃ or higher and cannot be used when high temperatures are to be avoided.
シランあるいはジシランを流す場合には、ガス分圧を小
さくする必袂がある。例えば、９５０℃の場合、ジン２
フ分圧を１０” ａｔｍ以下にする必要がある（ Ｙ、
Ｋｕｎｉｉ ａｎｄ Ｙ、５ａｋａｋｉｂａｒａ：Ｊａ
ｐａｎｅｓｅＪｏｕｒｎａｌ ｏｆ ＡｐｐＨｅｄ Ｐ
ｈｙｓｌｃｓ ２６（１９８２） １８１６参照）。こ
の値以上にすると酸化膜が除去できずシリコンが堆積さ
れてしまうからである。When flowing silane or disilane, it is necessary to reduce the gas partial pressure. For example, if the temperature is 950℃, gin 2
It is necessary to reduce the partial pressure to 10" atm or less (Y,
Kunii and Y, 5akakibara:Ja
paneseJournal of AppHed P
hyslcs 26 (1982) 1816). This is because if the value exceeds this value, the oxide film cannot be removed and silicon will be deposited.
［発明の効果コ
以上説明したように、本発明によれば、熱酸化工程の前
に初期酸化膜（洗浄酸化膜あるいは自然酸化膜）を除去
する工程を大気に曝すことなく連続して行うことＫよっ
て、次のような利点がある。[Effects of the Invention] As explained above, according to the present invention, the step of removing the initial oxide film (cleaned oxide film or natural oxide film) before the thermal oxidation step can be performed continuously without exposing it to the atmosphere. Therefore, there are the following advantages.
まず初期酸化膜がない状態から酸化を開始できるため、
形成された酸化膜は所望の温度と雰囲気ガスによって形
成されたもののみであり、初期酸化膜のような低温で形
成された品質の悪い酸化膜が含まれていない。次に、初
期酸化膜に含まれるあるいは表面に吸着している不純物
を、酸化膜除去工程で蒸発させてしまうことができ、不
純物汚染の面からも高品質となる。従って、酸化膜質や
不純物汚染に敏感なｆ−）酸化膜の耐圧や、ダイオード
およびトランジスタ歩留まりの向上が図られる。この効
果は、酸化膜厚が薄くなるに従い顕著になる。First, oxidation can be started from a state where there is no initial oxide film, so
The formed oxide film is only formed at the desired temperature and atmospheric gas, and does not include a poor quality oxide film formed at a low temperature such as the initial oxide film. Next, impurities contained in the initial oxide film or adsorbed on the surface can be evaporated in the oxide film removal process, resulting in high quality in terms of impurity contamination. Therefore, the withstand voltage of the f-) oxide film, which is sensitive to oxide film quality and impurity contamination, and the yield of diodes and transistors can be improved. This effect becomes more pronounced as the oxide film becomes thinner.
第１図は本発明の一実施例を示す構成説明図、第２図は
゛本発明に係る初期酸化膜除去可能条件の一例を示す特
性図である。
１ノ・・・反応管、１２・・・電気炉、１３・・・ガス
供給システム、１４・・・ガス排気システム、１５・・
・予備排気室、１６・・・ウェーハ搬送システム、１７
・・・ダートノ譬ルプ。FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention, and FIG. 2 is a characteristic diagram showing an example of the conditions under which the initial oxide film can be removed according to the present invention. 1 No... Reaction tube, 12... Electric furnace, 13... Gas supply system, 14... Gas exhaust system, 15...
・Preliminary exhaust chamber, 16...Wafer transfer system, 17
...Dirt no parable.
Claims (2)
成された酸化膜を除去する工程と、その後大気中に取り
出すことなく、所定の温度および雰囲気ガス中で熱酸化
する工程とから構成されていることを特徴とするシリコ
ン熱酸化膜形成方法。(1) It consists of a step of removing the natural oxide film on the surface of the silicon substrate or an oxide film formed by cleaning, and then a step of thermally oxidizing it in a predetermined temperature and atmospheric gas without taking it out into the atmosphere. A method for forming a silicon thermal oxide film, characterized by the following.
へのガス供給システム、および１×１０＾−＾７Ｔｏｒ
ｒ以下に排気可能なガス排気システム、および反応炉と
の間のバルブを設けた予備排気室、および予備排気室か
ら反応炉へシリコンウェーハを出し入れ可能とする搬送
システムから成り、反応炉中で熱酸化前処理と熱酸化を
連続的に行うことを特徴とするシリコン熱酸化膜形成装
置。(2) Reactor, electric furnace that heats it, gas supply system into the reactor, and 1×10^-^7 Tor
It consists of a gas exhaust system that can exhaust gas to below A silicon thermal oxide film forming apparatus characterized by continuously performing oxidation pretreatment and thermal oxidation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14644688A JPH022130A (en) | 1988-06-14 | 1988-06-14 | Method and device for forming silicon thermal oxide film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14644688A JPH022130A (en) | 1988-06-14 | 1988-06-14 | Method and device for forming silicon thermal oxide film |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH022130A true JPH022130A (en) | 1990-01-08 |
Family
ID=15407830
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14644688A Pending JPH022130A (en) | 1988-06-14 | 1988-06-14 | Method and device for forming silicon thermal oxide film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH022130A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0426120A (en) * | 1990-05-22 | 1992-01-29 | Nec Corp | Treating method for semiconductor substrate |
| US6399504B1 (en) * | 1996-03-05 | 2002-06-04 | Micron Technology, Inc. | Methods and etchants for etching oxides of silicon with low selectivity |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63111630A (en) * | 1986-10-30 | 1988-05-16 | Fujitsu Ltd | Manufature of semiconductor device |
| JPS63120428A (en) * | 1986-11-10 | 1988-05-24 | Fujitsu Ltd | Method and device for oxidation |
| JPS6481361A (en) * | 1987-09-24 | 1989-03-27 | Nec Corp | Manufacture of tunnel transistor |
-
1988
- 1988-06-14 JP JP14644688A patent/JPH022130A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63111630A (en) * | 1986-10-30 | 1988-05-16 | Fujitsu Ltd | Manufature of semiconductor device |
| JPS63120428A (en) * | 1986-11-10 | 1988-05-24 | Fujitsu Ltd | Method and device for oxidation |
| JPS6481361A (en) * | 1987-09-24 | 1989-03-27 | Nec Corp | Manufacture of tunnel transistor |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0426120A (en) * | 1990-05-22 | 1992-01-29 | Nec Corp | Treating method for semiconductor substrate |
| US6399504B1 (en) * | 1996-03-05 | 2002-06-04 | Micron Technology, Inc. | Methods and etchants for etching oxides of silicon with low selectivity |
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