JPS6256570A - Reactive sputtering method - Google Patents

Abstract

PURPOSE:To form a good-quality sputtered oxide film by preferentially introducing a sputtering gas in the vicinity of a target and preferentially introducing oxide forming oxygen in the vicinity of a substrate. CONSTITUTION:A sputtering chamber 1 is evacuated and cylinders 6 and 7 are opened to introduce gaseous Ar and gaseous O2 through inlet pipes 8 and 9. At this time, the gas pressure is regulated to about 10<-2>-10<-1>Pa, the gaseous Ar is introduced in the vicinity of the surface of a target 4 and the gaseous O2 is introduced in the vicinity of the surface of a substrate 5. A requisite voltage is impressed between an anode 2 and a cathode 3, the gaseous Ar is ionized on the surface of the target 4 and the target 4 is efficiently sputtered. Then the ion from the target 4 reacts with the gaseous O2 ionized due to the fall of potential in the vicinity of the surface of the substrate 5 and an oxide layer is deposited on the substrate 5. At this time, since the gaseous O2 flows preferentially in the vicinity of the surface of the substrate 5, the ion reacts sufficiently with excess gaseous O2, an oxide film of a stoichiometric composition is formed and an excellent oxide film having a uniform quality is obtained.

Description

【発明の詳細な説明】 〔技術分野〕 本発明は反応性スパッタリング方法に関し、特に膜質の
良いスパッタ膜を生成しつる反応性スパッタリング方法
に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a reactive sputtering method, and particularly to a reactive sputtering method that produces a sputtered film with good film quality.

〔従来技術とその問題点〕[Prior art and its problems]

従来の反応性スパッタ装置においては、スパッタ時に反
応性ガスがスパッタチャンバーに導入される。反応性ガ
スの導入方法に関しては従来全く考慮されておらず、例
えばアルゴンと酸素を例にとると、これらは別々の導入
口から、または予めアルゴンと酸素を混合した後半−の
導入口から、導入されていた。従来のスパッタ装置は、
アルゴンと酸素がチャンバー内でスパッタ及び成膜に関
与する前に均一に混合されるべきであるという考えに基
づいて設計されている。従って、一般に２種以上のガス
を同一または大体同一の個所から導入されている。とこ
ろが、実際にはスパッタ分子と反応ガス分子との反応は
主にターゲット表面近傍か又は基板表面近傍のどちらか
で生起するため、化学量論的な組成を有する膜を得るた
めには反応領域に反応ガスを送ることが有利である。例
えばＡｌ２Ｏ３膜をスパッタで製造する場合には、Ａｌ
２Ｏ３ターゲットをＡｒ及び０２の混合ガスでスパッタ
しても、基板面に形成される膜はＡｌ２Ｏ３こならず、
０が不足することが多い。このためざらにアニールなど
の後処理を必要とする。また酸素量を多くするとスパッ
タ率が低下しスパッタ速度がＡｒのみに比し又半分以下
となる。In conventional reactive sputtering equipment, a reactive gas is introduced into a sputtering chamber during sputtering. Conventionally, no consideration has been given to the method of introducing reactive gases; for example, taking argon and oxygen as an example, these can be introduced through separate inlet ports, or through a second inlet port where argon and oxygen are mixed in advance. It had been. Conventional sputtering equipment is
The design is based on the idea that argon and oxygen should be uniformly mixed in the chamber before participating in sputtering and deposition. Therefore, two or more gases are generally introduced from the same or approximately the same location. However, in reality, the reaction between sputtered molecules and reactive gas molecules mainly occurs either near the target surface or near the substrate surface, so in order to obtain a film with a stoichiometric composition, it is necessary to It is advantageous to send the reaction gas. For example, when manufacturing an Al2O3 film by sputtering,
Even if the 2O3 target is sputtered with a mixed gas of Ar and 02, the film formed on the substrate surface will not be Al2O3.
0 is often missing. Therefore, rough post-processing such as annealing is required. Furthermore, when the amount of oxygen is increased, the sputtering rate decreases, and the sputtering rate becomes less than half that of Ar only.

〔発明の目的〕[Purpose of the invention]

本発明は化学ｍ論的組成を有する金属酸化物又は窒化物
を製造しつる反応性スパッタリング方法を提供すること
を目的とする。It is an object of the present invention to provide a reactive sputtering method for producing metal oxides or nitrides having a stoichiometric composition.

本発明の他の目的はスパッタ率の良い反応性スパッタリ
ング方法を提供することにある。Another object of the present invention is to provide a reactive sputtering method with a high sputtering rate.

〔発明の概要〕[Summary of the invention]

本発明の反応性スパッタリング方法は、スパッタ用ガス
をターゲット表面近傍に、酸化物又は窒化物形成用ガス
を基板表面近傍に僅先的に導入することを特徴とする方
法である。The reactive sputtering method of the present invention is characterized in that a sputtering gas is slightly introduced into the vicinity of the target surface and an oxide or nitride forming gas is introduced into the vicinity of the substrate surface.

本発明によると、基板表面付近において生起する酸化物
又は窒化物形成反応が酸素や窒素の流れの存在下に促進
されて化学量論的組成の酸化物又は窒化物を容易に得る
ことができ、酸化物又は窒化物膜の特性を改善すること
ができる。According to the present invention, an oxide or nitride forming reaction occurring near the substrate surface is promoted in the presence of a flow of oxygen or nitrogen, and an oxide or nitride having a stoichiometric composition can be easily obtained. The properties of oxide or nitride films can be improved.

また、本発明によると、ターゲット近傍では酸素ガス濃
度や窒素ガス濃度が低いため、アルゴン等のスパッタ用
ガスが有効に働き、スパッタ率をさほど低下させないで
成膜反応が能率的に行うことができる。Further, according to the present invention, since the oxygen gas concentration and nitrogen gas concentration are low near the target, sputtering gas such as argon works effectively, and the film formation reaction can be performed efficiently without significantly reducing the sputtering rate. .

〔発明の構成〕[Structure of the invention]

第１図は本発−明による反応性スパッタリング方法を実
施する装置の概念図である。図中１はスパッタリング装
置のスパッタチャンバーであり、その内部に陽極２及び
陰極３が対向して設けられている。これらの電極間には
ＤＣ又はＲＦｌに圧が印加される。Ａｌ、　０．　、Ｓ
　ｔｏ、　、ＡＩＮ、　Ｓ　ＩＮ等のターゲット４は陽
極２の面に固定され、スパッタ基板５は陰極６の面に固
定されろ。チャンバー１の外部にはＡｒガス源（ボンベ
）６及びＯ７又はＮ、・ガス源（ボンベ）７が配置され
、Ａｒガス源６は導入管８を介してターゲット４の表面
近傍に導入され、またＯ、ガス又はＮ、ガス源７は導入
管９を介して基板５の表面近傍に導入される。FIG. 1 is a conceptual diagram of an apparatus for carrying out the reactive sputtering method according to the present invention. In the figure, reference numeral 1 denotes a sputtering chamber of a sputtering apparatus, in which an anode 2 and a cathode 3 are provided facing each other. A DC or RF1 pressure is applied between these electrodes. Al, 0. , S
Targets 4 such as TO, AIN, SIN, etc. are fixed on the surface of the anode 2, and the sputtering substrate 5 is fixed on the surface of the cathode 6. An Ar gas source (cylinder) 6 and an O or N gas source (cylinder) 7 are arranged outside the chamber 1, and the Ar gas source 6 is introduced into the vicinity of the surface of the target 4 via an introduction pipe 8. An O, gas, or N gas source 7 is introduced into the vicinity of the surface of the substrate 5 via an introduction pipe 9.

スパッタチャンバー１を排気して真空にし、ボンベ６．
７を開いてそれぞれＡｒガス及びＯ，ガス又はＮ、ガス
を導入する。ガス圧はチャンバー内の場所で異るが大体
１０″Ｊ〜１０”　Ｐ　ａ程度で運転する。新型の電圧
を陽極−陰極間に印加すると、Ａ　ｒガスはターゲット
表面でイオン化されターゲットを効率良くスパッタする
。ターゲット表面近くのＯ１濃度は低いため、スパッタ
率を高く保つことができろ。例えばＡｒガスの１０％が
Ｏ。Evacuate the sputter chamber 1 to a vacuum, and open the cylinder 6.
7 and introduce Ar gas and O gas or N gas, respectively. Although the gas pressure varies depending on the location within the chamber, it is generally operated at about 10"J to 10"Pa. When a new type of voltage is applied between the anode and cathode, the Ar gas is ionized on the target surface and sputters the target efficiently. Since the O1 concentration near the target surface is low, the sputtering rate can be kept high. For example, 10% of Ar gas is O.

ガスで置換されるならば純Ａｒガスに比べてスパッタ率
は４０〜５０％も低下するが、本発明ではターゲット表
面には主にＡｒガスが存在し、０！ガスの濃度は非常に
小さいからスパッタ率は２０％程度低下するに過ぎない
。次に、ターゲットからスパッタされたＡＩ、Ｓｉ等の
イオンは基板表面近くの電位降下により電離されている
酸素ガスと反応して基板上に酸化物層を析出する。酸素
は基板表面近傍に優先的に流されているから、金属イオ
ンは過剰の酸素により十分反応して化学ＭＡ組成の酸化
物膜を成膜することができる。このように、本発明は陽
極−陰極間に形成される電界が主としてこれら電極の表
面近くに存在することと、Ａｒ：ｊｆス及びＯ，ガスが
優先的にこれらの個所に分離して導入されることとによ
り、所望とする反応を効果的に行うことができるのであ
る。この方法は従来のように均一混合ガスの使用とは異
ってガス成分がチャンバー内に偏在するにも拘らず、却
ってすぐれた均一膜質の酸化物膜を生成しうろ点で、従
来の方法とは質的に異った方法である。If replaced with a gas, the sputtering rate would be reduced by 40 to 50% compared to pure Ar gas, but in the present invention, Ar gas is mainly present on the target surface, and 0! Since the gas concentration is very low, the sputtering rate is only reduced by about 20%. Next, the ions of AI, Si, etc. sputtered from the target react with oxygen gas that has been ionized due to a potential drop near the substrate surface, and deposit an oxide layer on the substrate. Since oxygen is flowed preferentially near the substrate surface, metal ions react sufficiently with excess oxygen to form an oxide film having a chemical MA composition. As described above, the present invention is characterized in that the electric field formed between the anode and the cathode exists mainly near the surfaces of these electrodes, and that the Ar:jf gas and O gas are preferentially introduced separately into these locations. By doing so, the desired reaction can be carried out effectively. Although this method differs from the conventional use of a homogeneous mixed gas in that the gas components are unevenly distributed within the chamber, it produces an oxide film with a superior uniform quality, and is superior to the conventional method. are qualitatively different methods.

以下実施例を説明する。Examples will be described below.

実施例１ Ａｌ、Ｏ，膜を形成する場合を例示する。ターゲラ）！
、：ＡＩ！０．焼結体を用い、形成する基板にガラス例
えば７０５９（商品名、フーニング社梨）を用いてＲＦ
ｔ力ＩＫＷのスパッタ装置でスパッタ成膜する。Example 1 A case where Al, O, and films are formed will be exemplified. Targera)!
, :AI! 0. Using a sintered body and using glass, for example, 7059 (trade name, manufactured by Hooning Co., Ltd.) as a substrate, RF
A sputter film is formed using a sputtering device with a t force of IKW.

まず、チャンバーを予じめ１０−ｊ　ｐ　、まで高真空
排気し、その後、ガラス基板を約２５０℃まで上昇させ
十分安定させる。First, the chamber is previously evacuated to a high vacuum of 10-j p , and then the glass substrate is heated to about 250° C. and sufficiently stabilized.

次に、スパッタガスとしてＡｒを導入し１×１　（）４
ｐ　ａまで導入し、その後、反応性ガスとして０．ガス
を６　Ｘ　１０”　〜８　Ｘ　１０４Ｐ　ａまで導入す
る。極間距離を約６０餌とすると電力密度で約３　Ｗ　
／　ｃｍ　”でスパッタすれば良好な膜が得られる膜の
化学量論性はＸ線分析や化学分析で行うのが正確である
が簡単な方法として膜の透過度（透明度）を見る方法が
ある。７厚を約１．０〜２．０μ程度つけ、そのａ明度
をｔｌべると酸素欠陥のある膜は、うす茶色に着色して
おり透明度が悪い。一方、その逆で十分良好な膜は完全
に無色透明でガラス板と全く同じとなる。以下図で本発
明方式と従来型を比べてみると、ｇＡ２図のようになっ
た。Next, Ar was introduced as a sputtering gas and 1×1 ()4
After that, the reactive gas was introduced up to 0. Introduce gas to 6 x 10" to 8 x 104 Pa. If the distance between poles is about 60 baits, the power density is about 3 W.
A good film can be obtained by sputtering at a speed of 0.3 cm / cm.The stoichiometry of a film can be accurately determined by X-ray analysis or chemical analysis, but a simple method is to check the permeability (transparency) of the film. .7 thickness is about 1.0 to 2.0 μm, and when you compare the brightness (tl), the film with oxygen defects is colored pale brown and has poor transparency.On the other hand, on the other hand, the film is sufficiently good. It is completely colorless and transparent, and is exactly the same as a glass plate.When comparing the method of the present invention and the conventional method in the figure below, the results are as shown in Figure gA2.

実施例２ ターゲットとしてＡＩＮ焼結体を用い、０！ガスの代り
にＮ、ガスを用い、他の条件はほぼ同様にして成膜した
ところ、透明性の高い窒化層ＡＩＮを得た。Example 2 Using an AIN sintered body as a target, 0! A highly transparent nitride layer AIN was obtained by forming a film using N and gas instead of gas, and under almost the same conditions as the other conditions.

第１図は本発明の方法を実施する装置の概念図である。FIG. 1 is a conceptual diagram of an apparatus for carrying out the method of the present invention.

第２図は本発明による膜と従来の膜とを比較するグラフ
で透明度と波長のＮ係を示す０１：スパンタチャンバー ２：陽極 ３：陰極 ４：ターゲット ５：基板 ６　：Ａｒガス源 ７：０．ガス源 ８：Ａｒ導入管 ９二〇、導入管 １□−噌へ 代理人の氏名　　倉　内　基　弘　　　□□− ／′）＼FIG. 2 is a graph comparing the film according to the present invention and a conventional film, showing the N ratio of transparency and wavelength 01: Spunter chamber 2: Anode 3: Cathode 4: Target 5: Substrate 6: Ar gas source 7: 0. Gas source 8: Ar introduction pipe 920, introduction pipe 1□- 噌 Name of agent Motohiro Kurauchi □□- /')\

Claims (1)

【特許請求の範囲】[Claims] １、基板に酸化物膜又は窒化物膜をスパッタ製膜する反
応性スパッタリング方法において、スパッタ用ガスはタ
ーゲット近傍に、酸化物又は窒化物形成用酸素又は窒素
ガスは基板近傍に優先的に導入することを特徴とする反
応性スパッタリング方法。1. In a reactive sputtering method for forming an oxide film or nitride film on a substrate by sputtering, sputtering gas is preferentially introduced near the target, and oxygen or nitrogen gas for forming oxide or nitride is preferentially introduced near the substrate. A reactive sputtering method characterized by: