JP2004356459A

JP2004356459A - Plasma treatment device

Info

Publication number: JP2004356459A
Application number: JP2003153679A
Authority: JP
Inventors: Akitaka Makino; 昭孝牧野; Hideyuki Kazumi; 秀之数見; Masamichi Sakaguchi; 正道坂口; Hiroaki Ishimura; 裕昭石村
Original assignee: Hitachi High Technologies Corp; Hitachi High Tech Corp
Current assignee: Hitachi High Tech Corp
Priority date: 2003-05-30
Filing date: 2003-05-30
Publication date: 2004-12-16
Anticipated expiration: 2023-05-30
Also published as: JP4474120B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment device capable of uniformly executing a processing to the outer peripheral part side of an object to be processed. <P>SOLUTION: The plasma treatment device is provided with a container whose inner side is evacuated, a sample base arranged on the inner side of the container, on which a sample is to be mounted, an antenna arranged above the sample base for radiating an electric field to the inner side of the container, a power source for supplying a high frequency to the sample base, and a cover arranged covering the sample base, arranged on the outer peripheral side of the sample through a gap with the outer peripheral end of the sample and constituted of an insulating member. The plasma treatment device is provided with a projection part arranged on the cover and provided with a corner part positioned above the outer peripheral end of the sample more on the outer peripheral side than the outer peripheral end of the sample. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、プラズマを用いて半導体ウエハ等の被処理物を処理して半導体装置や電子部品等を製造する装置に係り、特に、減圧された空間で被処理物に対しエッチング，ＣＶＤ等を行う装置に関する。
【０００２】
【従来の技術】
近年、プラズマ処理装置において、生産効率や歩留まりの向上の要求が高まっている。このために、半導体ウエハ等の被処理対象物のより外周側まで中央部側と同様の処理を行い製品として使用するため、被処理対象物のより大きな範囲についてより均一な処理を行うことが求められている。
【０００３】
このような要求に対しては、被処理物の処理対象表面の面方向についてより均一なプラズマを形成すること、あるいはより均一に被処理物にプラズマを入射させることが考えられてきた。
【０００４】
このような従来の技術としては、特開２００１−３２１６６２号公報（特許文献１）に記載されたものがあげられる。これらの従来技術では、プラズマ発生箇所においてプラズマ分布を均一化するために、処理装置に用いられる平板電極の周囲に複数個の素子を配置して各々を前記平板電極に接続して、各素子のインピーダンスの値を前記平板電極の電界分布が均一となるように選定するものである。
【０００５】
また、特開２００２−９０４７号公報（特許文献２）には、ウエハを接地する下部電極の内部に高周波で電力が印加される中央部から外周部に向かう方向に順次厚くなるように形成した誘電体を配置して、この下部電極の中央部周辺と外周部とでそのインピーダンスを異ならせることでこれらの箇所での電圧降下の大きさを異ならせて、その結果下部電極におけるウエハの被処理対象面の方向についての高周波電圧のピークツーピークを均一にするものが開示されている。
【０００６】
【特許文献１】
特開２００１−３２１６６２号公報
【特許文献２】
特開２００２−９０４７号公報
【０００７】
【発明が解決しようとする課題】
しかしながら、上記の従来の技術では、実際の装置内に被処理物が処理台上に載置された際にプラズマを均一に入射させる際の課題について、考慮が不足していた。
【０００８】
すなわち、このような処理物を載置する処理台上に載置された処理物の外周部側では、これに入射するプラズマあるいは処理台に印加される高周波の電界の分布が、乱れを生じて中央部側と異なっており、これにより中央部側と外周部側とで被処理物の処理が異なってしまうという問題点については考慮されていなかった。
【０００９】
本発明の目的は、被処理対象物の外周部側までより均一に処理を行うことのできるプラズマ処理装置を提供することにある。
【００１０】
【課題を解決するための手段】
上記目的は、その内側が減圧される容器と、この容器の内側に配置され試料がその上に載置される試料台と、この試料台の上方に配置され前記容器の内側に電界を放射するアンテナと、前記試料台に高周波を供給する電源と、前記試料台を覆って配置され前記試料の外周端と隙間を介してこの試料の外周側に配置され絶縁性部材より構成されるカバーとを備えたプラズマ処理装置であって、前記カバー上に配置され、前記試料の外周端より上方であって前記試料の外周端よりも外周側に位置する角部を有する凸部を備えたプラズマ処理装置により達成される。
【００１１】
また、その内側が減圧される容器と、この容器の内側に配置され試料がその上に載置される試料台と、この試料台の上方に配置され前記容器の内側に電界を放射するアンテナと、前記試料台の内側であって前記試料の下方に配置され高周波が印加される電極と、絶縁性部材で構成されその内側に前記試料がこの試料の外周端と隙間を介して配置されるリングと、前記リング上であって前記試料の外周端に沿って配置された凸部とを備え、この凸部が前記試料の外周端より上方であって前記試料の外周端よりも外周側に位置する角部を有するプラズマ処理装置により達成される。
【００１２】
【発明の実施の形態】
以下、本発明の一実施の形態を図面を用いて説明する。
【００１３】
図１は、本発明のプラズマ処理装置の構成の概略を示す縦断面図である。この図において、１はその内側でプラズマが形成されて処理が行われる真空処理室であり、その周囲は容器により囲まれている。４は、処理対象となる半導体ウエハ等の被処理物（試料）である。真空処理室１の内側には上記被処理物４がその上に載置される試料台３が配置されている。試料台３の真空処理室１上方には、ＵＨＦ等のプラズマ発生用の電磁波を供給する電源９からマッチング回路１１２や同軸ケーブルを介して伝達される高周波を真空処理室１内に供給するアンテナ６及びこれから発送される電磁波が通過して真空処理室１内に伝播する石英窓２が配置されている。さらに、この石英窓２の下方であって試料台３及び被処理物４の上方には、ガス源を含むガス流量調節器１０から供給される処理用ガスを、被処理物４の上方で拡散して真空処理室１内に導入するためのガス分散板（シャワープレート）８が配置されている。本実施の形態において供給されるガスは複数のガス源から複数のガスが供給されるが、求められる仕様に応じて単一のガス，単一のガス源を用いることもできる。
【００１４】
試料台３は、その内側に、導電性の部材で構成され、処理室内に形成されたプラズマの粒子を被処理物４表面に引き込んで処理を進めるためのバイアス電圧を形成するに必要な高周波が供給され試料台電極１３を備え、その周囲には絶縁性の物質を備えて構成されたサセプタ１２が試料台３の周囲を覆って配置されいる。試料台電極１３には、プラズマが形成されて被処理物４の処理が行われている間、高周波電源５からの高周波がマッチング回路１１１等を介して供給される。
【００１５】
この被処理物４が、試料台３上に載置された状態で、図示しない真空排気ポンプにより内側の気体が図１に示す矢印のように排気されて減圧された真空処理室１内に、ガス源からのガスがガス分散板８に設けられた複数の貫通孔１１から導入され、このガスに対してアンテナ６から放射される電波と真空処理室１の周囲に配置されたソレノイドコイル７から供給される磁界とが相互に作用してプラズマＰが形成される。このソレノイドコイル７は、上記電波により供給される電子の運動と位置とを調節するものであり、ソレノイドコイル７により供給される磁界を調節することでプラズマＰの密度とその分布や形成される位置を調節することができる。
【００１６】
このプラズマＰ内のイオンは、形成されるプラズマの領域の下部において、試料台３の試料台電極１３に供給される高周波によるバイアス電圧で試料台３側あるいは被処理物４表面に引き込まれて、被処理物４の表面に入射してこの表面をエッチングする。
【００１７】
サセプタ１２は、被処理物４が処理台上で載置された位置がズレることを抑制するために被処理物４の外周端と所定の隙間を介して被処理物（試料）の外周側を囲むように配置されている、リング形状の部材である。このサセプタ１２は、アルミナ等の絶縁性の部材により構成されている。すなわち、試料台３上の被処理物４を載置される表面との間に段差が設けられており、この段差により規定されるサセプタ１２のリング内側の凹んだ空間の領域に前記被処理物４が載置される。
【００１８】
また、本実施の形態では、このサセプタ１２の上面であってアンテナ６の方向に段差を有する凸部１４が配置されている。この凸部１４は、被処理物４の外周端あるいはサセプタ（リング）１２の内周端よりも外周側となる位置に角部を有しており、この凸部１４以外のサセプタ１２の上面は、被処理物４の上面とほぼ同じ高さとなるように構成されている。つまり、凸部１４及びその角部は前記被処理物４よりもアンテナ６に近くなるように配置されている。さらに、サセプタ１２には、被処理物４の外周端と隙間を介して位置する内周端と角部との間の表面には前記角部より低く構成された部分を有している。特に、本実施の形態では、後述する図３に示すように、角部とサセプタ１２の内周端との間には、外周側から内周に向かい傾斜する傾斜面が設けられている。
【００１９】
本実施の形態では、このような構成により、試料台３の上方のアンテナから放射された電波と試料台３内側の試料台電極１３に印加される高周波によるバイアス電圧とにより形成される電界の向きと強さを好適にして、被処理物４の外周側近傍での電界の乱れを抑制し、この外周部の近傍で電界が被処理物４の表面により垂直になりプラズマ中の荷電粒子がより試料表面に垂直に近い角度で入射させることができる。これは、被処理物４の外周端あるいはサセプタ１２の内周端よりもアンテナ６に近くこれらより試料台３の外周側に位置する凸部の角部に偏って向かうように電場が形成されることで、被処理物４の外周端には、その表面により垂直に向かう電界が構成できるからである。この偏った、あるいは集中した電界が被処理物４より外周側であって上方に形成することで、サセプタ１２を通って試料台電極１３へ向かう電界の流れ（向き）が安定しその乱れが生じることが抑制される。このためには、角部が、試料台電極１３の外周側であって、被処理物４の外周端あるいはサセプタ１２よりも外周側でこれらよりも上方（アンテナ６に近い位置）にあることが望ましい。
【００２０】
図２，図３は、本実施の形態の作用，効果を、従来の技術と比較して説明する断面図である。図２は、従来の技術によるプラズマ処理装置における被処理物の外周端近傍の電界の向きを示す摸式図である。図３は、上記実施の形態に係るプラズマ処理装置における被処理物の外周端近傍の電界の向きを示す摸式図である。
【００２１】
これらの図に示すように、図２の従来技術による装置では、被処理物４の外周端近傍とサセプタ１２との隙間には電界の乱れが生じてその向きに偏りが生じている。一方、図３の本実施の形態における被処理物４の外周端近傍では、凸部
１４の角部に電界の向きの偏りが生じているが、被処理物４の外周端では電界の向きはほぼ被処理物４の表面に垂直な方向を向いており、電界の乱れが抑制されていることが分かる。
【００２２】
このように、被処理物４の外周端部での電界の乱れが抑制されて、外周端部でもプラズマ中の粒子がより被処理物の表面に垂直に近い角度で入射することになり、被処理物の全体にわたってより均一に処理が行われることになる。
【００２３】
上記実施の形態では、凸部はその縦断面が矩形の形状を有しているが、この形状に限定されず他の形状でも良く、またその角部も縦断面が垂直の形状のみではなく、仕様に応じて適宜丸みや面取りがされた形状であっても、同様の作用・効果を奏することができる。
【００２４】
以上のように、上記実施の形態によれば、被処理対象物の外周部側までより均一に処理を行うことのできるプラズマ処理装置が提供できる。
【図面の簡単な説明】
【図１】本発明のプラズマ処理装置の構成の概略を示す縦断面図である。
【図２】従来の技術によるプラズマ処理装置における被処理物の外周端近傍の電界の向きを示す摸式図である。
【図３】図１に示す実施の形態における被処理物の外周端近傍の電界の向きを示す摸式図である。
【符号の説明】
１…真空処理室、２…石英窓、３…試料台、４…被処理物、５…高周波電源、６…アンテナ、７…ソレノイドコイル、８…ガス分散板、９…ＵＨＦ電源、１０…ガス流量調節器、１１…貫通孔、１２…サセプタ、１３…試料台電極、１４…凸部、１１１，１１２…マッチング回路。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for manufacturing a semiconductor device, an electronic component, or the like by processing an object to be processed such as a semiconductor wafer using plasma, and in particular, performs etching, CVD, or the like on the object to be processed in a reduced-pressure space. Equipment related.
[0002]
[Prior art]
2. Description of the Related Art In recent years, there has been an increasing demand for improvement in production efficiency and yield in plasma processing apparatuses. For this reason, in order to use the same processing as that of the central part side to the outer peripheral side of the object to be processed such as a semiconductor wafer and use it as a product, it is necessary to perform more uniform processing over a larger range of the object to be processed. Have been.
[0003]
In response to such demands, it has been considered to form more uniform plasma in the surface direction of the surface of the object to be processed or to make the plasma more uniformly incident on the object to be processed.
[0004]
Such a conventional technique is described in Japanese Patent Application Laid-Open No. 2001-321662 (Patent Document 1). In these conventional techniques, in order to make the plasma distribution uniform at a plasma generation location, a plurality of devices are arranged around a plate electrode used in a processing apparatus, and each of the devices is connected to the plate electrode. The value of the impedance is selected so that the electric field distribution of the plate electrode becomes uniform.
[0005]
Japanese Unexamined Patent Application Publication No. 2002-9047 (Patent Document 2) discloses a dielectric formed in a lower electrode for grounding a wafer such that the thickness is gradually increased in a direction from a central portion to which an electric power is applied at a high frequency toward an outer peripheral portion. The lower electrode has different impedances at the periphery and at the center of the lower electrode, so that the magnitude of the voltage drop at these points is different. A device that makes the peak-to-peak of the high-frequency voltage uniform in the direction of the surface is disclosed.
[0006]
[Patent Document 1]
JP 2001-321662 A [Patent Document 2]
JP-A-2002-9047
[Problems to be solved by the invention]
However, in the above-described conventional technology, consideration has not been given to the problem of uniformly injecting plasma when an object to be processed is placed on a processing table in an actual apparatus.
[0008]
That is, on the outer peripheral side of the processing object placed on the processing table on which such a processing object is mounted, the distribution of the plasma incident thereon or the high-frequency electric field applied to the processing table is disturbed. It is different from the central part side, and the problem that the processing of the object to be processed is different between the central part side and the outer peripheral part side has not been considered.
[0009]
An object of the present invention is to provide a plasma processing apparatus capable of performing processing more uniformly to the outer peripheral portion side of an object to be processed.
[0010]
[Means for Solving the Problems]
The above object is to provide a container whose inside is decompressed, a sample stage placed inside the container and a sample placed thereon, and an electric field radiated inside the container arranged above the sample stage. An antenna, a power supply for supplying high frequency to the sample stage, and a cover arranged over the sample stage and arranged on an outer peripheral side of the sample via an outer peripheral end of the sample and a gap and formed of an insulating member. A plasma processing apparatus, comprising: a projection disposed on the cover and having a corner located above an outer peripheral end of the sample and located on an outer peripheral side of an outer peripheral end of the sample. Is achieved by
[0011]
Further, a container whose inside is decompressed, a sample table placed inside the container and a sample placed thereon, and an antenna arranged above the sample table and radiating an electric field inside the container, An electrode which is disposed inside the sample stage and below the sample, to which a high frequency is applied, and a ring which is formed of an insulating member and in which the sample is disposed with a gap with the outer peripheral end of the sample. And a convex portion disposed on the ring and along the outer peripheral end of the sample, and the convex portion is located above the outer peripheral end of the sample and on the outer peripheral side of the outer peripheral end of the sample. This can be achieved by a plasma processing apparatus having a corner portion that forms.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0013]
FIG. 1 is a longitudinal sectional view schematically showing the configuration of the plasma processing apparatus of the present invention. In this figure, reference numeral 1 denotes a vacuum processing chamber in which plasma is formed and processing is performed inside, and the periphery thereof is surrounded by a container. Reference numeral 4 denotes an object to be processed (sample) such as a semiconductor wafer to be processed. Inside the vacuum processing chamber 1, a sample table 3 on which the object 4 is placed is disposed. Above the vacuum processing chamber 1 of the sample stage 3, an antenna 6 for supplying a high frequency transmitted from a power supply 9 for supplying an electromagnetic wave for generating plasma such as UHF via a matching circuit 112 or a coaxial cable into the vacuum processing chamber 1. In addition, a quartz window 2 through which electromagnetic waves to be transmitted and transmitted through the vacuum processing chamber 1 are disposed. Further, a processing gas supplied from a gas flow controller 10 including a gas source is diffused above the workpiece 4 below the quartz window 2 and above the sample table 3 and the workpiece 4. A gas dispersion plate (shower plate) 8 for introducing the gas into the vacuum processing chamber 1 is provided. In the present embodiment, a plurality of gases are supplied from a plurality of gas sources, but a single gas or a single gas source may be used according to required specifications.
[0014]
The sample stage 3 is formed of a conductive member inside, and a high frequency necessary for forming a bias voltage for drawing plasma particles formed in the processing chamber to the surface of the processing target 4 and advancing the processing is provided. A supplied sample stage electrode 13 is provided, and a susceptor 12 configured to include an insulating material is arranged around the sample stage electrode 3 so as to cover the sample stage 3. The high frequency from the high frequency power supply 5 is supplied to the sample stage electrode 13 via the matching circuit 111 and the like while the plasma is formed and the processing of the processing object 4 is performed.
[0015]
In a state where the object to be processed 4 is placed on the sample stage 3, the inside gas is evacuated by an evacuation pump (not shown) as shown by an arrow in FIG. A gas from a gas source is introduced from a plurality of through holes 11 provided in a gas dispersion plate 8, and a radio wave radiated from the antenna 6 for the gas and a solenoid coil 7 disposed around the vacuum processing chamber 1. The supplied magnetic field interacts to form plasma P. The solenoid coil 7 adjusts the movement and position of the electrons supplied by the radio wave, and adjusts the magnetic field supplied by the solenoid coil 7 to control the density of the plasma P, its distribution and the position at which it is formed. Can be adjusted.
[0016]
The ions in the plasma P are drawn into the sample stage 3 side or the surface of the workpiece 4 by a high-frequency bias voltage supplied to the sample stage electrode 13 of the sample stage 3 below the region of the plasma to be formed. The light enters the surface of the object to be processed 4 and is etched.
[0017]
The susceptor 12 moves the outer peripheral side of the workpiece (sample) through a predetermined gap with the outer peripheral edge of the workpiece 4 in order to suppress the position of the workpiece 4 placed on the processing table from shifting. It is a ring-shaped member arranged so as to surround it. The susceptor 12 is made of an insulating member such as alumina. That is, a step is provided between the sample table 3 and the surface on which the object 4 is placed, and the object to be processed is located in a concave space inside the ring of the susceptor 12 defined by the step. 4 is placed.
[0018]
In the present embodiment, a convex portion 14 having a step in the direction of the antenna 6 on the upper surface of the susceptor 12 is arranged. The convex portion 14 has a corner at a position closer to the outer peripheral end than the outer peripheral end of the workpiece 4 or the inner peripheral end of the susceptor (ring) 12, and the upper surface of the susceptor 12 other than the convex portion 14 , And is substantially the same height as the upper surface of the workpiece 4. That is, the convex portion 14 and its corner are arranged closer to the antenna 6 than the object 4 to be processed. Further, the susceptor 12 has a portion that is lower than the corner portion on the surface between the outer peripheral end of the workpiece 4 and the inner peripheral end located through the gap and the corner portion. In particular, in the present embodiment, as shown in FIG. 3 described later, an inclined surface that is inclined from the outer peripheral side toward the inner peripheral side is provided between the corner and the inner peripheral end of the susceptor 12.
[0019]
In the present embodiment, with such a configuration, the direction of the electric field formed by the radio wave radiated from the antenna above the sample stage 3 and the high-frequency bias voltage applied to the sample stage electrode 13 inside the sample stage 3 And the strength are suppressed to suppress the disturbance of the electric field near the outer peripheral side of the object to be processed 4, and the electric field becomes more perpendicular to the surface of the object to be processed 4 near this outer peripheral portion, so that the charged particles in the plasma are more reduced. The light can be incident on the sample surface at an angle close to normal. This is because the electric field is formed so as to be closer to the antenna 6 than the outer peripheral end of the workpiece 4 or the inner peripheral end of the susceptor 12 and to be biased toward the corner of the convex portion located on the outer peripheral side of the sample table 3. This is because a vertical electric field can be formed on the outer peripheral end of the processing target 4 by its surface. Since the biased or concentrated electric field is formed on the outer peripheral side and above the object to be processed 4, the flow (direction) of the electric field toward the sample stage electrode 13 through the susceptor 12 is stabilized, and the disturbance occurs. Is suppressed. For this purpose, the corner may be on the outer peripheral side of the sample stage electrode 13 and on the outer peripheral end of the workpiece 4 or on the outer peripheral side of the susceptor 12 (above the antenna 6). desirable.
[0020]
2 and 3 are cross-sectional views for explaining the operation and effect of the present embodiment in comparison with a conventional technique. FIG. 2 is a schematic diagram showing the direction of an electric field near the outer peripheral end of an object to be processed in a conventional plasma processing apparatus. FIG. 3 is a schematic diagram showing the direction of an electric field near the outer peripheral end of the workpiece in the plasma processing apparatus according to the above embodiment.
[0021]
As shown in these figures, in the apparatus according to the prior art shown in FIG. 2, the electric field is disturbed in the gap between the vicinity of the outer peripheral end of the object 4 and the susceptor 12, and the direction is biased. On the other hand, in the vicinity of the outer peripheral end of the processing target 4 in the present embodiment of FIG. It is almost perpendicular to the surface of the object 4 to be processed, and it can be seen that the disturbance of the electric field is suppressed.
[0022]
In this manner, the disturbance of the electric field at the outer peripheral end of the processing target 4 is suppressed, and the particles in the plasma also enter the surface of the processing target at an angle closer to perpendicular to the outer peripheral end. Processing will be performed more uniformly over the entire processed material.
[0023]
In the above embodiment, the convex portion has a rectangular shape in vertical section, but is not limited to this shape, and may have another shape. Even if the shape is rounded or chamfered appropriately according to the specification, the same operation and effect can be obtained.
[0024]
As described above, according to the embodiment, it is possible to provide a plasma processing apparatus capable of performing processing more uniformly to the outer peripheral side of the object to be processed.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view schematically showing a configuration of a plasma processing apparatus of the present invention.
FIG. 2 is a schematic diagram showing a direction of an electric field near an outer peripheral end of an object to be processed in a conventional plasma processing apparatus.
FIG. 3 is a schematic diagram showing a direction of an electric field near an outer peripheral end of an object to be processed in the embodiment shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Vacuum processing chamber, 2 ... Quartz window, 3 ... Sample table, 4 ... Workpiece, 5 ... High frequency power supply, 6 ... Antenna, 7 ... Solenoid coil, 8 ... Gas dispersion plate, 9 ... UHF power supply, 10 ... Gas Flow rate controller, 11: through hole, 12: susceptor, 13: sample stage electrode, 14: convex part, 111, 112: matching circuit.

Claims

A container whose inside is decompressed, a sample stage placed inside the container and a sample placed thereon, an antenna arranged above the sample stage and radiating an electric field inside the container, Plasma processing comprising: a power supply for supplying high frequency to a sample stage; and a cover disposed over the sample stage and arranged on an outer peripheral side of the sample via a gap with an outer peripheral end of the sample and formed of an insulating member. A device,
A plasma processing apparatus, comprising: a projection disposed on the cover and having a corner located above an outer peripheral end of the sample and on an outer peripheral side of the outer peripheral end of the sample.

A container whose inside is decompressed, a sample table placed inside the container and a sample placed thereon, an antenna arranged above the sample table and radiating an electric field inside the container, An electrode which is arranged below the sample and applied with a high frequency inside the sample stage, and a ring which is formed of an insulating member and in which the sample is arranged with a gap between the outer peripheral end of the sample and the inside thereof, A convex portion on the ring and arranged along the outer peripheral end of the sample, wherein the convex portion is located above the outer peripheral end of the sample and located on the outer peripheral side of the outer peripheral end of the sample. Plasma processing apparatus having a part.