JP3553692B2 - Plasma vapor deposition apparatus and method for removing thin film of deposition shield in plasma vapor deposition apparatus - Google Patents

Description

まず、表１に示す通り、上記条件による酸化硅素薄膜の作成において、防着シールド５にシールドバイアス電圧を印加した場合の基板上の成膜速度は５２５ｎｍ／分であり、印加しない場合の４８０ｎｍ／分に比べると、成膜速度が約１０％向上していた。また、プラズマエッチングが終了するまでの時間は、基板上への薄膜作成時にシールドバイアス電圧を印加していた場合には３０分で済むが、印加していなかった場合には４５分の時間を要した。このことは、上記シールドバイアス電圧の印加によって防着シールド５への薄膜堆積を２／３に抑制できることを意味している。
【００３５】
また、基板を２５枚処理するごとに上記プラズマエッチングによる薄膜除去を行い、計１８５０枚の基板を処理した後の基板へのパーティクルの付着状況を測定した。即ち、１８５０枚めの基板の処理の後、上述のようなプラズマエッチングによる薄膜除去を行い、その後新たな基板を真空容器１に搬入して処理を行った。そして、その処理の後、その基板の表面に付着していたパーティクルの数をレーザー光散乱法で測定した。表２にレーザー光散乱法による散乱断面積０．２８μｍ^２ 以上のパーティクルの測定結果を示す。
【００３６】
【表２】

表２に示す通り、シールドバイアス電圧を印加しないで薄膜作成を行った場合には、目視観察でも防着シールド５に堆積した酸化硅素薄膜が剥離していることがわかり、パーティクルの数も１０００個以上と多いことがわかった。一方、シールドバイアス電圧を印加して薄膜作成を行った場合には、パーティクルが２０個以下に激減していた。
尚、基板バイアス電圧を印加した場合には、同様に２０個以下であった。これは、プラズマエッチングによる薄膜除去の際に、防着シールド５から飛来して基板ホルダー４に付着する材料も同時に除去することで、パーティクルの原因となる薄膜堆積を基板ホルダー４も含めて完全に除去できた効果である。
【００３７】
また、基板ホルダー４に基板バイアス電圧を印加した場合としない場合では、基板ホルダー４に付着した酸化膜の表面状態が異なることが観察できた。印加しない場合、表面は白濁して粉状の様子を呈すのに対し、印加した場合には無色透明で、その後も継続してパーティクル発生の心配なく基板を処理できることが推定された。
また、プラズマエッチングによる薄膜除去の際に防着シールド５にシールドバイアス電圧を印加しない場合には、四フッ化炭素ガス／酸素ガスの流量を４００ｓｃｃｍ／２００ｓｃｃｍと増加させても、２４時間プラズマエッチングによる薄膜除去を継続しても、防着シールド５上の薄膜は除去できず、極めてエッチング速度が小さいことがわかった。このことから、薄膜の堆積した部分にバイアス電圧を印加することが、堆積薄膜のエッチング除去に要する時間の短縮に非常に有効であることが確認された。
【００３８】
上記実施例の説明において、基板バイアス電圧及びシールドバイアス電圧は、「プラズマと高周波との相互作用」により印加されるとして説明したが、堆積又は作成する薄膜が導電体である場合には、直流電源によってもこれらを印加することが可能である。但し、高周波電源によってこれらを印加する方が、薄膜材料等の点で受ける制約が少なくなるので、汎用性の意味から好適である。
【００３９】
また上述した実施例のプラズマ気相成長装置は、ヘリコン波プラズマを利用するように構成を変更することができる。ヘリコン波プラズマは、強い磁場を加えるとプラズマ振動数より低い周波数の電磁波が減衰せずにプラズマ中を伝搬することを利用するものであり、高密度プラズマを低圧で生成できる技術として最近注目されているものである。プラズマ中の電磁波の伝搬方向と磁場の方向とが平行のとき、電磁波はある定まった方向の円偏光となり螺旋状に進行する。このことからヘリコン波プラズマと呼ばれている。
ヘリコン波プラズマを形成する場合には、一本の棒状の部材を曲げて上下二段の丸いループ状に形成したループ状アンテナを図１の高周波コイル３１に代えてベルジャー１１の外側を取り囲むようにして配置し、その外側にヘリコン波用磁場設定手段としての直流の電磁石をベルジャー１２と同心上に配置する。整合器２２を介して高周波電源２３から１３．５６ＭＨｚの高周波をベルジャー１２内に供給すると、磁場の作用によって上記ヘリコン波プラズマが形成される。
【００４０】
【発明の効果】
以上説明したように、本願の請求項１の発明によれば、真空容器の内面への材料の付着が防止され、薄膜剥離によって生ずる塵埃の発生を効果的に抑制することが可能となる。また、成膜中に防着シールドに負の電圧であるシールドバイアス電圧が印加されるため、防着シールドに付着した材料が再放出されて基板上の薄膜作成に寄与する結果、基板への成膜速度も向上する。また尚、防着シールドが真空容器に対して絶縁されている結果、真空容器にシールドバイアス電圧が印加されることがなく、この点で安全である。
また、請求項２の発明によれば、上記請求項１の効果に加え、プラズマと高周波との相互作用によりシールドバイアス電圧が印加されるので、薄膜材料の点で制約が少なく、汎用性が高いというメリットがある。
また、請求項３の発明によれば、基板バイアス電圧印加機構を有するので、基板の表面に荷電粒子を衝突させながら薄膜作成等を行うことができる。
また、請求項４の発明によれば、上記請求項２又は３の効果に加え、基板表面に形成された孔又は溝を薄膜堆積によって塞ぐ際に、薄膜中に空洞が形成されることがないという効果が得られる。
また、請求項５の発明によれば、上記請求項１，２，３又は４の効果に加え、防着シールドの交換によって塵埃の発生を未然に防止することができ、この点でさらに好適である。
また、請求項６の発明によれば、上記請求項１，２，３，４又は５の効果に加え、防着シールドの温度が最適な値に調節されるので、防着シールドを薄膜堆積しない温度にしたり、また逆に薄膜堆積したとしても剥離しない温度にしたりすることが可能となる。
また、請求項７の発明によれば、上記請求項１，２，３，４，５又は６の効果に加え、防着シールドと真空容器との間の空間での放電が抑制されるので、放電による部材の損傷やスパッタによる異物の放出等を防ぐことができる。
またさらに、請求項８の発明によれば、防着シールドのエッチングによる薄膜除去の際にシールドバイアス電圧が印加されるので、エッチングの効率が向上し、薄膜除去完了までの時間を短縮することができる。
さらに、請求項９の発明によれば、請求項８と同様、防着シールドのエッチングによる薄膜除去の際にシールドバイアス電圧が印加されるので、エッチングの効率が向上し、薄膜除去完了までの時間を短縮することができる。またこの際、エッチングされて防着シールドから放出された材料が基板ホルダーに再付着して薄膜堆積するのが抑制されるため、さらに好適な良質な薄膜作成に寄与することができる。
【図面の簡単な説明】
【図１】本願発明の実施例のプラズマ気相成長装置の概略図である。
【図２】図１のガス導入体２１２，２２２の構成を説明する図である。
【図３】従来のプラズマ気相成長装置の一例の概略図である。
【図４】基板の表面に形成された孔又は溝を薄膜で塞ぐようにする薄膜作成の例の説明図である。
【符号の説明】
１ 真空容器
１１ 排気系
２ ガス導入機構
３ 電力供給機構
４ 基板ホルダー
４２ 基板バイアス電圧印加機構
５ 防着シールド
５１ シールドバイアス電圧印加機構
５２ シート保持体
５３ シールドシート
５４ 温度調節機構
５５ 放電防止部材[0001]
[Industrial applications]
The present invention relates to a plasma vapor deposition apparatus used for forming various thin films on the surface of a substrate.
[0002]
[Prior art]
When manufacturing a large-scale integrated circuit (LSI) or a liquid crystal display (LCD), a process of forming various thin films on the surface of a substrate is required. As an apparatus for forming a thin film, a vacuum evaporation apparatus, a sputtering apparatus, and the like are known, but a plasma vapor deposition apparatus is often used because a compound or an amorphous thin film can be formed at a relatively low temperature. .
[0003]
FIG. 3 is a schematic view of an example of a conventional plasma vapor deposition apparatus. The plasma vapor deposition apparatus shown in FIG. 3 includes a vacuum vessel 1 having an exhaust system 11, a gas introduction mechanism 2 for introducing a predetermined gas into the vacuum vessel 1, and a plasma by giving energy to the introduced gas. It is mainly composed of a power supply mechanism 3 for forming, a substrate holder 4 for mounting a substrate 40 for forming a thin film, and the like.
In the apparatus shown in FIG. 3, the substrate 40 is carried into the vacuum vessel 1 through a gate valve (not shown) and placed on the substrate holder 4. After the inside of the vacuum vessel 1 is evacuated by the exhaust system 11,Gas introduction mechanism 2To introduce a predetermined gas. Next, energy such as high frequency power is applied to the gas in the vacuum vessel 1 by the power supply mechanism 3 to form plasma. Then, a predetermined thin film is deposited on the surface of the substrate by a gas phase reaction generated by the plasma. For example,Gas introduction mechanism 2When a silane gas and an oxygen gas are introduced, a decomposition reaction or the like is caused by the plasma, and a silicon oxide thin film is formed on the surface of the substrate 40.
[0004]
In the plasma vapor deposition apparatus, an electric field may be set between the plasma and the surface of the substrate 40 so that charged particles in the plasma collide with the surface of the substrate 40 in some cases. For example, in a film forming technique called an ion assist method, ions are made to collide with the surface of the substrate 40 with relatively weak acceleration energy during film formation, and the energy of the ions is used to efficiently grow a thin film. .
[0005]
To set an electric field between the plasma and the substrate 40, a bias voltage (hereinafter, a substrate bias voltage) is applied so that the surface of the substrate 40 has a predetermined potential with respect to the plasma potential (電位 0). This substrate bias voltage is usually applied by the interaction between plasma and high frequency. That is, as shown in FIG. 3, a high frequency power supply 422 for a substrate is connected to the substrate holder 4, and high frequency power is applied to the substrate 40 through the substrate holder 4. In the positive half cycle of the applied high frequency, the electrons in the plasmaSubstrate 40, But in the negative half cycle, ions with low mobility are collected slowly. Due to such a difference in mobility, electrons are gathered on the surface of the substrate 40 to be in the same state as when a negative bias voltage is applied. As a result, an electric field is set between the substrate and the plasma.
[0006]
[Problems to be solved by the invention]
The application of the substrate bias voltage as described above has recently been performed also in the case of producing a thin film in which a hole or a groove formed on the surface of the substrate 40 is closed with the thin film. FIG. 4 is an explanatory diagram of an example of forming a thin film in which holes or grooves formed on the surface of the substrate are covered with the thin film.
As shown in FIG. 4A, a thin-film pattern 400 made of, for example, a metal is formed as a wiring on the surface of the substrate 40, and a hole or a groove 401 exists according to the shape of the pattern 400. When another pattern is formed on the upper layer of the pattern 400, the pattern 400 is covered with an insulating film 402 to insulate the layers.
[0007]
In this case, when a normal thin film is formed without applying the substrate bias voltage, particles serving as the material of the thin film are difficult to reach the bottom of the hole or groove 401 and easily collect on the upper surface of the pattern 400. As described above, the thin film grows so as to bulge round from the upper surface of the pattern 400 to the upper edge of the hole or full 401. As a result, as shown in FIG. 4C, even if the hole or the groove 401 is closed by the thin film, a cavity 403 called a poid is formed in the thin film. When such a cavity 403 is formed, it penetrates into the cavity 403.OrDue to the presence of moisture or the like, the withstand voltage between the metal wiring patterns 400 is significantly degraded, which causes a serious failure that short-circuits the integrated circuit.
[0008]
Therefore, an electric field is set between the plasma and the surface of the substrate 40 by applying a substrate bias voltage, and ions in the plasma are extracted and collided by the electric field. In the case shown in FIG. 4A, the electric field is steepest at the corner of the upper edge of the hole or groove 401, and therefore, the ion strikes this portion most often. As a result, the thin film deposited on this portion is etched, and a part of the etched material reaches the inside of the hole or groove 401. For this reason, the difference in the film formation rate between the inside of the hole or groove 401 and the upper surface of the pattern 400 is improved, and as shown in FIGS. The groove 401 can be closed with a thin film. In this case, since it is necessary to etch the thin film, a higher acceleration electric field is generally set as compared with the above-described ion assist method.
[0009]
the aboveIn a plasma vapor deposition apparatus, it is inevitable that a thin film is deposited on the inner surface of a vacuum container as the thin film is continuously formed. This thin film deposition occurs because particles floating in the vacuum vessel adhere to the inner surface of the vacuum vessel. When the thin film deposited on the inner surface reaches a certain thickness, it is peeled off and becomes dust. If the dust adheres to the substrate, the circuit pattern may be broken or short-circuited, resulting in serious circuit defects.
The invention of the present application has been made to solve the above-mentioned problems, and it is possible to prevent a material from adhering to the inner surface of a vacuum vessel and effectively suppress generation of dust caused by peeling of a thin film. It is intended to provide a phase growth apparatus.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 of the present application provides a vacuum vessel provided with an exhaust system, a gas introduction mechanism for introducing a predetermined gas into the vacuum vessel, and energy supplied to the introduced gas. A power supply mechanism for forming a plasma, and comprising a power supply mechanism for forming a predetermined thin film on the surface of the substrate using a gas phase reaction generated by the plasma,
It is arranged in a state of being insulated from the vacuum container so as to cover the inner surface of the vacuum container, and prevents the material floating in the vacuum container from adhering to the inner surface of the vacuum container and preventing the deposition of a thin film on the inner surface. A shield bias voltage applying mechanism for setting an electric field between the shield and the plasma and applying a shield bias voltage for causing charged particles in the plasma to collide with the shield.And
The deposition prevention shield surrounds the substrate being formed,
The shield bias applying mechanism applies a negative shield bias voltage to the deposition shield during film formation.It is a configuration.
Similarly, in order to achieve the above object, according to a second aspect of the present invention, in the configuration of the first aspect, the shield bias voltage applying mechanism is configured to apply a shield bias voltage by interaction with plasma. Contains.
Similarly, in order to achieve the above object, the invention according to claim 3 is the invention according to claim 1 or 2, wherein a predetermined voltage is applied to the substrate to cause charged particles in the plasma to collide with the surface of the substrate. A substrate bias voltage application mechanism for applying a substrate bias voltage is provided.
Similarly, in order to achieve the above object, according to the invention of claim 4, in the configuration of claim 2 or 3, the substrate bias voltage applying mechanism etches a corner of a hole or groove formed on the surface of the substrate. Meanwhile, a substrate bias voltage is applied so that the holes or grooves are closed by the deposition of the thin film.
Similarly, in order to achieve the above object, in the invention according to claim 5, in the configuration according to claim 1, 2, 3, or 4, the shield is provided replaceably.
Similarly, in order to achieve the above object, in the invention according to claim 6, in the configuration of claim 1, 2, 3, 4, or 5, a temperature adjusting mechanism for controlling the temperature of the deposition prevention shield is provided.
Similarly, in order to achieve the above object, according to the invention of claim 7, in the configuration of claim 1, 2, 3, 4, 5 or 6, the space between the deposition-inhibiting shield and the inner surface of the vacuum vessel is provided. And a discharge prevention member for preventing discharge in the space.
Similarly, in order to achieve the above object, an invention according to claim 8 removes a thin film deposited on the deposition shield of the plasma vapor deposition apparatus according to claim 1, 2, 3, 4, 5, 6, or 7. In the method of removing a thin film, a predetermined gas is introduced by a gas introduction mechanism, energy is applied to the introduced gas by a power supply mechanism to form a plasma, and the plasma is formed on the deposition shield by a material generated in the plasma. The thin film is removed by etching, and at the time of this etching removal, a predetermined shield bias voltage is applied to the deposition-inhibiting shield by a shield bias voltage applying mechanism.
Similarly, in order to achieve the above object, an invention according to claim 9 is a method for removing a thin film deposited on the deposition-inhibiting shield of the plasma vapor deposition apparatus according to claim 3 or 4, wherein the gas introducing mechanism is provided. A predetermined gas is introduced, and the introduced gas is energized by the power supply mechanism to form a plasma, and a thin film deposited on the deposition-inhibiting shield is etched and removed by a material generated in the plasma. In addition, at the time of this etching removal, a predetermined shield bias voltage is applied to the deposition-inhibiting shield by the shield bias voltage applying mechanism, and further, the substrate bias voltage applying mechanism applies a substrate bias to a substrate holder on which the substrate is placed. The substrate bias voltage is applied together with the shield bias voltage application mechanism. Structure is operated, has a configuration that performs while applying a substrate bias voltage to the substrate holder.
[0011]
【Example】
Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a schematic view of a plasma vapor deposition apparatus according to an embodiment of the present invention. 1 is a vacuum vessel 1 provided with an exhaust system 11, a gas introduction mechanism 2 for introducing a predetermined gas into the vacuum vessel 1, and a gas introduction apparatus, similar to the apparatus shown in FIG. And a substrate holder 4 on which a substrate on which a thin film is to be formed is placed.
[0012]
Further, the apparatus shown in FIG. 1 is disposed so as to cover the inner surface of the vacuum vessel 1 and is insulated from the vacuum vessel 1, and prevents the material floating in the vacuum vessel 1 from adhering to the inner surface of the vacuum vessel 1. A shield 5 for preventing deposition of a thin film on the inner surface, and a shield for setting an electric field between the shield 5 and the plasma to cause charged particles in the plasma to collide with the shield 5. And a shield bias voltage applying mechanism 51 for applying a bias voltage.
[0013]
First, the vacuum vessel 1 forms a film forming chamber 101 and a vacuum evacuation chamber 102 of a slightly larger space located below the film forming chamber 101. In addition, a part configuring the film forming chamber 101 and a part configuring the vacuum exhaust chamber 102 are configured to be separable. This is for replacement of the deposition shield 5 described later.
A gate valve (not shown) is provided on the wall of the vacuum chamber 1 in the film forming chamber 101, and an exhaust pipe 13 to which the exhaust system 11 is connected is provided in the wall of the vacuum exhaust chamber 102. I have. The exhaust system 11 includes a roughing pump 111, a main pump 112 disposed in a stage preceding the roughing pump 111, a main valve 113 and a variable conductance valve 114 disposed on an exhaust path for exhausting the pumps 111 and 112. It is mainly composed of
The vacuum vessel 1 has a bell jar 12 on the upper side. A circular opening is provided at the center of the upper vessel wall of the vacuum vessel 1, and the bell jar 12 is connected to the opening in an airtight manner. The bell jar 12 has a cylindrical shape with a diameter of about 100 mm having a hemispherical tip and an open lower end, and is formed of a dielectric material such as quartz glass.
[0014]
In the example shown in FIG. 1, the gas introduction mechanism 2 includes two gas introduction systems 21 and 22 so that two different gases can be introduced at the same time. Each of the gas introduction systems 21 and 22 mainly includes pipes 211 and 221 connected to a gas cylinder (not shown), and gas introduction bodies 212 and 222 connected to the ends of the pipes 211 and 221.
FIG. 2 is a diagram illustrating the configuration of the gas introduction body. As shown in FIG. 2, the gas introduction bodies 212 and 222 are each formed of an annular pipe having a circular cross section. The gas introduction bodies 212 and 222 are supported by support rods 23 provided in the vacuum vessel 1 and are horizontally arranged along the inner surface of the vacuum vessel 1. In addition, the vacuum container 1 may be a cylindrical shape or a rectangular tube shape.
[0015]
A transport pipe 24 is provided so as to penetrate the wall of the vacuum vessel 1 in an airtight manner, and one end of the transport pipe 24 is connected to the gas introduction bodies 212 and 222. The other ends of the gas introduction bodies 212 and 222 are connected to the pipes 211 and 221 in FIG.
As shown in FIG. 2, the gas introduction bodies 212 and 222 have a gas outlet 25 on the inner surface thereof. The gas outlet 25 is an opening having a diameter of about 0.5 mm, and is provided on the periphery at an interval of about 25 mm.
[0016]
On the other hand, returning to FIG. 1, the power supply mechanism 3 mainly includes a high-frequency coil 31 disposed around the bell jar 12 and a high-frequency power supply 33 that supplies high-frequency power to the high-frequency coil 31 via a matching unit 32. Is configured. The high-frequency power supply 33 is configured to generate, for example, 13.56 MHz high-frequency power, and the high-frequency coil 31 supplies the high-frequency power into the bell jar 12.
[0017]
A substrate holder 4 is provided below the bell jar 12 in the vacuum vessel 1. The substrate holder 4 mounts a substrate 40 on which a thin film is to be formed on an upper surface, and incorporates a temperature control mechanism 41 for heating or cooling the substrate 40 as necessary.
The substrate holder 4 is provided with a substrate bias voltage applying mechanism 42 for applying a predetermined substrate bias voltage to the substrate 40 by the interaction between the generated plasma and the high frequency. The substrate bias voltage applying mechanism 42 includes a substrate matching device 421 and a substrate high-frequency power supply 422 that generates a predetermined high-frequency power to be applied via the substrate matching device 421. The "bias voltage due to the interaction between plasma and high frequency" includesHigh frequency power supply 422 for the boardIt is necessary that a considerable capacitance exists between the plasma and the plasma. Therefore, when the substrate holder 4 and the substrate 40 are all made of metal, a predetermined capacitor is connected on a power supply circuit to the substrate holder 40.
[0018]
The deposition shield 5, which is one of the major features of the apparatus of the present embodiment, is held on the front surface of the sheet holder 52, which is attached to the vacuum container 1 in an insulated state. It mainly comprises a shield sheet 53.
The sheet holder 52 is a substantially cylindrical member, and has a shape in which the inner diameter gradually decreases as it goes upward as shown in FIG. The curved portion of the inner surface of the sheet holder 52 is located on the substrate holder 4.Substrate 40Are formed so as to form a substantially spherical surface with respect to the center point of.
[0019]
The upper end of the sheet holder 52 has reached the vicinity of the upper wall of the vacuum vessel 11, and the upper edge thereof is in contact with the lower end of the bell jar 12 although it is not clear from the drawing. Further, the lower end portion of the sheet holder 52 is located so as to surround the outside of the substrate holder 4, and the lower edge thereof is located slightly lower than the upper surface of the substrate holder 4.
The upper and lower ends of the sheet holder 52 are bent inward, and the sheet holder 52 is sandwiched between the bent portions.Get caughtThus, the shield sheet 53 is arranged. The shield sheet 53 is a thin sheet having a thickness of about 3 mm formed of a material such as pure aluminum.
[0020]
A temperature control mechanism 54 is provided in the deposition shield 5 having the above-described configuration. The temperature control mechanism 54 includes a temperature control block 541 disposed behind the sheet holder 52, a pipe 542 that penetrates through the temperature control block 541 and connects to a medium passage, and a temperature control block 541 through the pipe 542. And a temperature control unit 543 for sending a medium for temperature control to the control unit.
The temperature control block 541 is made of a material having good heat conductivity such as an aluminum alloy, and is disposed in contact with the sheet holder 52 with good heat conductivity. The temperature control unit 543 sends liquid or gas into the temperature control block 541 to control the temperature. For example, by maintaining the deposition shield 5 at a predetermined high temperature, deposition of a thin film on the deposition shield 5 may be prevented. In such a case, the temperature adjustment mechanism 54 operates to activate the deposition shield 5. Adjust to the specified temperature. Further, at a certain temperature, the peeling of the deposited thin film may be suppressed. By maintaining the deposition prevention shield 5 at this temperature, even if the thin film is deposited, it is possible to prevent the thin film from peeling and generating dust. Can be.
[0021]
A discharge prevention member 55 is arranged between the temperature control block 541 and the vacuum vessel 1. The discharge prevention member 55 is configured to fill the space according to the shape of the space formed by the temperature control block 541 and the vacuum vessel 1. The discharge prevention member 55 of this embodiment has a shape in which a plate having an L-shaped cross section is rounded to have a circumferential shape, and is formed of a dielectric material such as quartz glass.
By filling the space formed between the deposition-inhibiting shield 5 and the vacuum vessel 1 with the discharge preventing member 55 made of a dielectric material, it is possible to prevent plasma from entering the space and generating a discharge. When a discharge is generated in such a portion, the constituent member is damaged by the discharge, and the constituent member is sputtered to release foreign matters.
[0022]
Next, a description will be given of a shield bias voltage applying mechanism 51 which is another feature of the apparatus of the present embodiment.
The shield bias voltage applying mechanism 51 of the present embodiment mainly includes a shield matching device 511 and a shield high-frequency power source 512 that generates a predetermined high-frequency power to be applied to the deposition shield 5 via the shield matching device 511. It is configured. That is, similarly to the substrate bias voltage applying mechanism 42, the shield bias voltage applying mechanism 51 of the present embodiment employs a mechanism for generating a "bias voltage due to the interaction between plasma and high frequency".
The power supply line from the matching device for shield 511 is connected to the sheet holder 52. The shield sheet 53 is held with respect to the sheet holder 52 as described above, so that both keep good electrical contact. Further, similarly to the substrate bias voltage applying mechanism 42, a capacitor is disposed on the power supply line as needed.
[0023]
Next, the operation of the plasma vapor deposition apparatus of the present embodiment having the above configuration will be described.
First, the substrate 40 is carried into the vacuum container 1 through a gate valve (not shown) provided in the vacuum container 1 and placed on the substrate holder 4. The gate valve is closed and the exhaust system 11 is operated to evacuate the vacuum vessel 1 to, for example, about 5 mTorr.
Next, the gas introduction mechanism 2 is operated to introduce a predetermined gas into the vacuum vessel 1 at a predetermined flow rate. At this time, the gas is supplied from the pipes 211 and 221 to the gas introduction bodies 212 and 222 via the transport pipe 24, and is blown inward from the gas outlets 25 of the gas introduction bodies 212 and 222 so that the inside of the vacuum vessel 1 is Will be introduced. The introduced gas diffuses inside the vacuum vessel 1 and reaches inside the bell jar 12.
[0024]
In this state, the power supply mechanism 3 is operated, and high-frequency power of about 13.56 MHz 2500 W is applied to the high-frequency coil 31 from the high-frequency power supply 33 via the matching unit 32. At the same time, the substrate bias voltage applying mechanism 4242 and the shield bias voltage applying mechanism 51 also operate, and a predetermined bias voltage is applied to the substrate 40 and the shield 5.
The high-frequency power supplied by the power supply mechanism 3 is introduced into the bell jar 12 via the high-frequency coil 31 and gives energy to the gas present in the bell jar 12 to generate plasma. The generated plasma diffuses from the bell jar 12 toward the substrate 40 below. A predetermined product is generated in the plasma, and the product reaches the substrate 40 to form a predetermined thin film.
For example, when forming a silicon oxide thin film, a monosilane gas is introduced by a first gas introduction system 21 and an oxygen gas is introduced by a second gas introduction system 22. Monosilane is decomposed by the monosilane / oxygen plasma and reacts with oxygen to form a silicon oxide thin film.
[0025]
At this time, the charged particles in the plasma collide with the surface of the substrate 40 by the substrate bias voltage applied by the substrate bias voltage applying mechanism 42. For example, when a thin film is formed in a hole or a groove as described above, a high-frequency power of about 13.56 MHz and 2400 W is applied to the substrate from the high-frequency power supply 422 for the substrate. As a result, as shown in FIGS. 4B and 4C, the holes or grooves can be closed with a thin film without forming a cavity.
[0026]
On the other hand, as described above, when the plasma vapor deposition apparatus of the present embodiment is operating, a material having a thin film deposition action on the deposition shield 5 is floating in the vacuum vessel 1. That is, a material that forms a thin film by adhering to the surface of the substrate 40 may simultaneously adhere to the deposition-inhibiting shield 5 and deposit a thin film. In particular, when a thin film is formed on a hole or a groove while operating the substrate bias voltage applying mechanism 42 as described above, the film deposited on the upper edge of the hole or the groove is sputtered by the ions, and It is re-emitted and floats. The floating material adheres and stays on the surface of the shield sheet 53, and when the amount of the stay reaches a considerable amount and time, the adhered material grows into a thin film on the surface of the shield sheet 53.
However, since the shield bias voltage application mechanism 51 operates as described above and a predetermined shield bias voltage is applied to the deposition-inhibiting shield 5, the growth of the thin film on the surface of the shield sheet 53 is suppressed. That is, the shield bias voltageNegative voltage applied by mechanism 42A predetermined electric field is formed between the deposition shield 5 and the plasma by the shield bias voltage, and ions in the plasma accelerated by the electric field sputter the thin film deposited on the surface of the shield sheet 53. As a result, deposition of the thin film is suppressed.
[0027]
It should be further noted that when the shield bias voltage applying mechanism 51 is operated as described above, the thin film deposited on the shield sheet 53 is sputtered by the ions in the plasma and released into the vacuum chamber 1 again. Some of the re-emitted material reaches the surface of the substrate 40 and contributes to the formation of a thin film on the surface of the substrate. Therefore, when the shield bias voltage applying mechanism 51 is operated, an important secondary effect is obtained in that the deposition of the thin film on the shield sheet 53 is suppressed and the film forming speed on the surface of the substrate 40 is improved.
[0028]
The substrate bias voltage applied to the substrate 40 by the substrate bias voltage applying mechanism 42 is smaller than the shield bias voltage applied to the deposition shield 5 by the shield bias voltage applying mechanism 51. This means that the shield bias voltage 5 completely suppresses thin film deposition, whereas the substrate bias voltage deposits at the corners of the upper edge of the hole or groove 401 as shown in FIG. This is because the thin film is sputtered to promote the deposition of the thin film in the hole or the groove 401, and does not completely suppress the deposition of the thin film on the substrate 4.
[0029]
Further, even if the shield bias voltage applying mechanism 51 is operated as described above, it is inevitable that a certain amount of thin film is deposited on the surface of the shield sheet 53 if the thin film forming process is continued for a very long time. In this case, the thin film is removed by plasma etching or the shield sheet 53 is replaced with another one.
[0030]
When performing plasma etching, a fluorine-based gas such as carbon tetrafluoride is introduced into the vacuum chamber 1 by the gas introduction mechanism 2, and plasma is formed as described above. Fluorine active species are generated in the plasma, and the fluorine active species reach the surface of the shield sheet 53 and react with the thin film, whereby the thin film is etched away. That is, the fluorine active species reacts with the thin film to form a compound having a high vapor pressure, and is removed by being exhausted by the exhaust system.
It is more preferable to operate the substrate bias voltage applying mechanism 42 to apply the substrate bias voltage during the plasma etching. That is, even if the material released from the deposition shield 5 adheres to the substrate holder 4, the charged particles accelerated by the substrate bias voltage repel the adhered substance and suppress the growth of a thin film on the substrate holder 4. .
[0031]
When replacing the shield sheet 53, the upper part of the vacuum vessel 1 is lifted and separated from the lower part, and the old shield sheet 53 is removed from the sheet holder 52. Then, a new shield sheet 53 is similarly set and held on the sheet holder 52, and then the upper portion of the vacuum vessel 1 is airtightly connected to the lower portion.
[0032]
Next, the result of an experiment for confirming the effect of the plasma vapor deposition apparatus of the present embodiment will be described.
Tables 1 and 2 show the results of experiments confirming the effects of the plasma vapor deposition apparatus of the present embodiment. Explaining the conditions of this experiment, the introduced gas is 100 sccm of monosilane and 300 sccm of oxygen. Here, sccm is an abbreviation for standard cubic centimeter per minute, and is represented by the amount (volume) of gas flowing per minute at 0 ° C. and 1 atm. The high frequency provided by the power supply mechanism 3 was 13.56 MHz 2.5 kW, the high frequency provided by the substrate bias voltage applying mechanism 42 was 13.56 Hz 2.5 kW, and the high frequency provided by the shield bias voltage applying mechanism 51 was 400 kHz 2 kW.
[0033]
After continuously processing 25 substrates under these conditions, in order to remove the thin film deposited on the deposition-inhibiting shield 5, 200 sccm of carbon tetrafluoride gas and 100 sccm of oxygen gas were introduced by the gas introduction mechanism 2 to supply power. The plasma etching was performed by supplying a high frequency of 2 kW by the mechanism 3. At this time, a high frequency of 2.5 kW was applied to the deposition shield 5. The time point at which the plasma etching was completed was measured by detecting a change in the impedance of the deposition shield 5 and the like. That is, when the thin film deposited on the deposition shield 5 is completely removed, the impedance of the deposition shield 5 as a load of the high-frequency circuit returns to the original state before the start of the processing. The removal can be completed.
[0034]
[Table 1]

First, as shown in Table 1, in forming a silicon oxide thin film under the above conditions, the film formation rate on the substrate when a shield bias voltage was applied to the deposition-inhibiting shield 5 was 525 nm / min, and 480 nm / min when no shield bias voltage was applied. The film formation rate was improved by about 10% compared to the minute. The time required for plasma etching to be completed is 30 minutes when a shield bias voltage is applied when a thin film is formed on a substrate, but requires 45 minutes when a shield bias voltage is not applied. did. This means that the deposition of the thin film on the deposition shield 5 can be suppressed to 2/3 by the application of the shield bias voltage.
[0035]
In addition, every time 25 substrates were processed, the thin film was removed by the plasma etching described above, and the state of adhesion of particles to the substrates after processing a total of 1850 substrates was measured. That is, after the processing of the 1850th substrate, the thin film was removed by the plasma etching as described above, and then a new substrate was loaded into the vacuum vessel 1 and the processing was performed. After the treatment, the number of particles adhering to the surface of the substrate was measured by a laser light scattering method. Table 2 shows the scattering cross section by laser light scattering method of 0.28 μm.²  The measurement results of the above particles are shown.
[0036]
[Table 2]

As shown in Table 2, when the thin film was formed without applying the shield bias voltage, it was found by visual observation that the silicon oxide thin film deposited on the deposition shield 5 was peeled off, and the number of particles was 1,000. It turned out that there was much above. On the other hand, the shield bias voltageApplyWhen a thin film was formed, the number of particles was sharply reduced to 20 or less.
When a substrate bias voltage was applied, the number was similarly 20 or less. This is because when the thin film is removed by plasma etching, the material flying from the deposition shield 5 and adhering to the substrate holder 4 is also removed at the same time, so that the deposition of the thin film causing the particles is completely completed including the substrate holder 4. This is the effect that could be removed.
[0037]
Further, it was observed that the surface state of the oxide film adhered to the substrate holder 4 was different between the case where the substrate bias voltage was applied to the substrate holder 4 and the case where the substrate bias voltage was not applied. It was presumed that when no voltage was applied, the surface became turbid and powdery, whereas when voltage was applied, the substrate was colorless and transparent, and the substrate could be processed continuously without concern for particle generation.
When no shield bias voltage is applied to the deposition-inhibiting shield 5 when removing the thin film by plasma etching, even if the flow rate of carbon tetrafluoride gas / oxygen gas is increased to 400 sccm / 200 sccm, plasma etching is performed for 24 hours. Even if the removal of the thin film was continued, the thin film on the deposition shield 5 could not be removed, indicating that the etching rate was extremely low. From this, it was confirmed that applying a bias voltage to the portion where the thin film was deposited was very effective in shortening the time required for etching and removing the deposited thin film.
[0038]
In the above description of the embodiment, the substrate bias voltage and the shield bias voltage are described as being applied by “interaction between plasma and high frequency”. However, when the thin film to be deposited or formed is a conductor, a DC power supply is used. It is also possible to apply these. However, it is preferable from the viewpoint of versatility to apply these with a high-frequency power supply, because restrictions on thin film materials and the like are reduced.
[0039]
The configuration of the plasma vapor deposition apparatus of the above-described embodiment can be changed so as to use helicon wave plasma. Helicon wave plasma utilizes the fact that electromagnetic waves of a frequency lower than the plasma frequency propagate through the plasma without attenuation when a strong magnetic field is applied, and has recently been attracting attention as a technology that can generate high-density plasma at low pressure. Is what it is. When the direction of propagation of the electromagnetic wave in the plasma is parallel to the direction of the magnetic field, the electromagnetic wave becomes circularly polarized light in a certain direction and travels in a spiral. For this reason, it is called helicon wave plasma.
When helicon wave plasma is formed, a loop-shaped antenna formed by bending a single rod-like member into a two-stage upper and lower round loop is replaced with the high-frequency coil 31 of FIG. A DC electromagnet as a helicon wave magnetic field setting means is arranged concentrically with the bell jar 12 on the outside thereof. When a high frequency of 13.56 MHz is supplied into the bell jar 12 from the high frequency power supply 23 via the matching unit 22, the helicon wave plasma is formed by the action of the magnetic field.
[0040]
【The invention's effect】
As described above, according to the first aspect of the present invention, it is possible to prevent the material from adhering to the inner surface of the vacuum vessel and effectively suppress the generation of dust caused by the thin film peeling. Also,During film formationFor protective shieldNegative voltageSince the shield bias voltage is applied, the material adhered to the deposition shield is re-emitted and contributes to the formation of a thin film on the substrate. As a result, the film forming speed on the substrate is also improved. Further, since the deposition shield is insulated from the vacuum vessel, no shield bias voltage is applied to the vacuum vessel, which is safe in this respect.
According to the second aspect of the invention, in addition to the effect of the first aspect, the shield bias voltage is applied by the interaction between the plasma and the high frequency, so that there is little restriction in terms of the thin film material and the versatility is high. There is a merit.
According to the third aspect of the present invention, since a substrate bias voltage applying mechanism is provided, a thin film can be formed while colliding charged particles with the surface of the substrate.
According to the invention of claim 4, in addition to the effect of claim 2 or 3, there is no formation of a cavity in the thin film when closing the hole or groove formed on the substrate surface by depositing the thin film. The effect is obtained.
According to the fifth aspect of the present invention, in addition to the effects of the first, second, third, and fourth aspects, the generation of dust can be prevented beforehand by exchanging the deposition shield. is there.
According to the sixth aspect of the invention, in addition to the effects of the first, second, third, fourth or fifth aspect, the temperature of the deposition shield is adjusted to an optimum value, so that the deposition shield is not deposited as a thin film. It is possible to set the temperature or, conversely, the temperature at which the thin film is not separated even if it is deposited.
According to the seventh aspect of the invention, in addition to the effects of the first, second, third, fourth, fifth or sixth aspect, the discharge in the space between the deposition-inhibiting shield and the vacuum vessel is suppressed. Damage to members due to electric discharge and emission of foreign matter due to sputtering can be prevented.
Furthermore, according to the invention of claim 8, since the shield bias voltage is applied when the thin film is removed by etching the deposition shield, the efficiency of etching is improved, and the time until the removal of the thin film is shortened. it can.
Further, according to the ninth aspect of the present invention, similarly to the eighth aspect, the shield bias voltage is applied at the time of removing the thin film by etching the anti-adhesion shield, so that the etching efficiency is improved and the time until the completion of the thin film removal is improved. Can be shortened. Further, at this time, since the material released from the deposition shield by etching is prevented from re-adhering to the substrate holder and depositing a thin film, it is possible to contribute to the production of a more suitable high-quality thin film.
[Brief description of the drawings]
FIG. 1 is a schematic view of a plasma vapor deposition apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a configuration of gas introduction bodies 212 and 222 in FIG.
FIG. 3 is a schematic view of an example of a conventional plasma vapor deposition apparatus.
FIG. 4 is an explanatory diagram of an example of forming a thin film in which holes or grooves formed on the surface of a substrate are closed with a thin film.
[Explanation of symbols]
1 vacuum container
11 Exhaust system
2 Gas introduction mechanism
3 Power supply mechanism
4 Board holder
42 Substrate bias voltage application mechanism
5 Protection shield
51 Shield bias voltage application mechanism
52 Sheet holder
53 shield sheet
54 Temperature control mechanism
55 Discharge prevention member

Claims (9)

A vacuum vessel provided with an exhaust system, a gas introduction mechanism for introducing a predetermined gas into the vacuum vessel, and a power supply mechanism for applying energy to the introduced gas to form a plasma, which are generated by the plasma. In a plasma vapor deposition apparatus that creates a predetermined thin film on the surface of a substrate using a vapor phase reaction,
It is arranged in a state of being insulated from the vacuum container so as to cover the inner surface of the vacuum container, and prevents the material floating in the vacuum container from adhering to the inner surface of the vacuum container and preventing the deposition of a thin film on the inner surface. a deposition shield that, possess a shield bias voltage applying mechanism for applying a shield bias voltage for by setting the electric field impinging charged particles in the plasma to the deposition preventing shield between the deposition shield and the plasma ,
The deposition prevention shield surrounds the substrate being formed,
The plasma vapor deposition apparatus, wherein the shield bias applying mechanism applies a negative shield bias voltage to the deposition shield during film formation . 2. The plasma vapor phase epitaxy apparatus according to claim 1, wherein said shield bias voltage applying mechanism includes a high frequency power supply for applying a shield bias voltage by interaction with plasma. 3. The plasma according to claim 1, further comprising a substrate bias voltage applying mechanism for applying a predetermined voltage to the substrate to apply a substrate bias voltage for causing charged particles in the plasma to collide with a surface of the substrate. Vapor growth equipment. The substrate bias voltage applying mechanism applies a substrate bias voltage while etching the corners of the holes or grooves formed on the surface of the substrate so that the holes or grooves are closed by the thin film deposition. The plasma vapor deposition apparatus according to claim 2, wherein The plasma vapor deposition apparatus according to claim 1, 2, 3, or 4, wherein the deposition shield is replaceably provided. 6. The plasma vapor deposition apparatus according to claim 1, further comprising a temperature control mechanism for controlling a temperature of the deposition shield. The discharge prevention member for preventing discharge in the space is provided in a space between the deposition prevention shield and the inner surface of the vacuum vessel. 7. The plasma vapor deposition apparatus according to 5 or 6. 8. A thin film removing method for removing a thin film deposited on the deposition shield of the plasma vapor deposition apparatus according to claim 1, 2, 3, 4, 5, 6, or 7, wherein a predetermined gas is introduced by the gas introduction mechanism. A plasma is formed by applying energy to the introduced gas by the power supply mechanism, and a thin film deposited on the deposition-inhibiting shield is etched and removed by a material generated in the plasma. And applying a predetermined shield bias voltage to the deposition shield using the shield bias voltage application mechanism. 5. A thin film removing method for removing a thin film deposited on the deposition shield of the plasma vapor deposition apparatus according to claim 3 or 4, wherein a predetermined gas is introduced by the gas introducing mechanism, and the power supply mechanism is supplied to the introduced gas. Plasma is formed by applying energy to the plasma, and the thin film deposited on the deposition shield is removed by etching with the material generated in the plasma, and at the time of this etching removal, the thin film is prevented by the shield bias voltage applying mechanism. A predetermined shield bias voltage is applied to the receiving shield, and the substrate bias voltage applying mechanism applies a substrate bias voltage to a substrate holder on which the substrate is mounted. Operate the bias voltage application mechanism and apply the substrate bias voltage to the substrate holder Adhesion-preventing film removal method of the shield, which comprises carrying out while.

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