JP2011054894A - Method for forming oxide film - Google Patents

Method for forming oxide film Download PDF

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JP2011054894A
JP2011054894A JP2009204865A JP2009204865A JP2011054894A JP 2011054894 A JP2011054894 A JP 2011054894A JP 2009204865 A JP2009204865 A JP 2009204865A JP 2009204865 A JP2009204865 A JP 2009204865A JP 2011054894 A JP2011054894 A JP 2011054894A
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cvd
film
film forming
ozone
oxide film
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Naoto Kameda
直人 亀田
Tetsuya Nishiguchi
哲也 西口
Hidehiko Nonaka
秀彦 野中
Shingo Ichimura
信吾 一村
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Meidensha Corp
Meidensha Electric Manufacturing Co Ltd
National Institute of Advanced Industrial Science and Technology AIST
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Meidensha Electric Manufacturing Co Ltd
National Institute of Advanced Industrial Science and Technology AIST
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for achieving the production of a film having an excellent interface characteristic by enhancing the adhesion between an oxide film and a CVD film. <P>SOLUTION: The method for forming an oxide film in a processing chamber 205 includes an oxidation step of forming an oxide film on a treated substrate by supplying only an ozone containing gas to the treated substrate, and a CVD step of forming the oxide film composed of oxide components of a material gas on the treated substrate by supplying the CVD material gas and the ozone containing gas to the treated substrate which has undergone the oxidation step. The film production rate at the early stage of the CVD step is controlled so as to be smaller than the film production rate of the oxidation step. Further, the method preferably includes an annealing step of exposing the treated substrate which has undergone the CVD step to the atmosphere of ozone containing gas or to the atmosphere of the ozone containing gas irradiated with light having a wavelength in the ultraviolet light region, and a step of submitting the treated substrate which has undergone the annealing step to the CVD step. It is more preferable to repeat a plurality of times the step of submitting the treated substrate which has undergone the annealing step to the CVD step. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

本発明はオゾン含有ガスが適用される酸化絶縁膜作製プロセス、ポリシリコンＴＦＴ、ＦＥＴゲート酸化膜等の半導体の製造技術に関する。   The present invention relates to an oxide insulating film manufacturing process to which an ozone-containing gas is applied, and a semiconductor manufacturing technology such as a polysilicon TFT and an FET gate oxide film.

半導体プロセスにオゾンガスを導入することにより、製膜プロセスの低温化が可能となっている。特にＳｉ酸化では、オゾンに紫外光（波長：２００〜３００ｎｍ）を照射することにより発生する光励起オゾン（Ｏ（1Ｄ））を用いて４００℃以下でも酸化が可能となっている。ここでオゾンの光分解の反応式は「Ｏ3→Ｏ（1Ｄ）+Ｏ2」である。光励起オゾン酸化により４００℃以下で作製されたＳｉ酸化膜は、優れた絶縁特性・界面特性を持つことから、ＴＦＴやＦＥＴ素子のゲート絶縁膜として有用であることが明らかになっている（特許文献１）。更に、ポリシリコン基板に光励起オゾン酸化を適用することで、ポリシリコン基板面上を均一厚みの酸化膜が得られた（非特許文献１）。ここで、ポリシリコン基板は、単結晶シリコンウエハとは異なり、表面に析出する結晶方位面が幾つも存在するため、均一な厚みの酸化膜を得るためには、酸化速度が結晶方位の影響を受けてはならないことが要求される。ところが従来の酸素を用いたＳｉ酸化では、ポリシリコン基板上に均一な酸化膜を作ることができないことからも、光励起オゾン酸化は、ポリシリコンデバイスや低温作製デバイス（例えばフレキシブルディスプレイ）作製において極めて重要な役割を果たすことが予想される。 By introducing ozone gas into the semiconductor process, the temperature of the film forming process can be lowered. In particular, in Si oxidation, oxidation is possible even at 400 ° C. or lower using photoexcited ozone (O ( 1 D)) generated by irradiating ozone with ultraviolet light (wavelength: 200 to 300 nm). Here, the reaction formula of ozone photolysis is “O 3 → O ( 1 D) + O 2 ”. Si oxide films produced at 400 ° C. or lower by photoexcited ozone oxidation have excellent insulating characteristics and interface characteristics, and thus have been found to be useful as gate insulating films for TFTs and FET elements (Patent Document) 1). Furthermore, by applying photo-excited ozone oxidation to the polysilicon substrate, an oxide film having a uniform thickness was obtained on the polysilicon substrate surface (Non-patent Document 1). Here, unlike a single crystal silicon wafer, a polysilicon substrate has a number of crystal orientation planes deposited on the surface. Therefore, in order to obtain an oxide film with a uniform thickness, the oxidation rate is influenced by the crystal orientation. It is required not to receive. However, since the conventional Si oxidation using oxygen cannot form a uniform oxide film on the polysilicon substrate, photoexcited ozone oxidation is extremely important in the production of polysilicon devices and low-temperature fabrication devices (for example, flexible displays). Expected to play a role.

また、光励起オゾンは酸化以外に、ＣＶＤによる酸化膜の低温製膜にも有用である。例えば、テトラエトキシシラン（以下、ＴＥＯＳと称する）またはヘキサメチルジシラン（以下、ＨＭＤＳと称する）を原料ガスとして光励起オゾンとＣＶＤプロセスを行うと、４００℃以下でＳｉＯ2膜を作製することが可能である。こうしてできたＣＶＤ−ＳｉＯ2膜は、他の低温ＳｉＯ2製膜プロセスであるプラズマＣＶＤに比べ、少ない濃度の膜中不純物および優れた絶縁性を有する（特許文献２）。 In addition to oxidation, photoexcited ozone is useful for low-temperature deposition of an oxide film by CVD. For example, when photoexcited ozone and a CVD process are performed using tetraethoxysilane (hereinafter referred to as TEOS) or hexamethyldisilane (hereinafter referred to as HMDS) as a source gas, a SiO 2 film can be formed at 400 ° C. or lower. is there. The CVD-SiO 2 film thus formed has a low concentration of impurities in the film and excellent insulation as compared with plasma CVD, which is another low-temperature SiO 2 film forming process (Patent Document 2).

このことから光励起オゾンを用いたＣＶＤ技術は、低温製膜技術として注目が集まっている。このような技術は、基板の融点の低い材料（ガラスやプラスチック）上へのデバイス素子作りに特に有効である。図２のようの融点の低い材料１０１上にＳｉ単結晶またはポリシリコンやアモルファスシリコン１０２を堆積させた上にＴＦＴ１０３やＦＥＴ１０４を作るとき、高温プロセスが必要になると材料１０１が劣化してしまうためである。   For this reason, the CVD technique using photoexcited ozone has attracted attention as a low temperature film forming technique. Such a technique is particularly effective for making a device element on a material (glass or plastic) having a low melting point of the substrate. When the TFT 103 or the FET 104 is formed on the material 101 having a low melting point as shown in FIG. 2 on which Si single crystal, polysilicon, or amorphous silicon 102 is deposited, the material 101 deteriorates if a high temperature process is required. is there.

特開２００６−２７００４０号公報JP 2006-270040 A 特開２００６−８０４７４号公報JP 2006-80474 A 特開２００８−２４３９２６号公報JP 2008-243926 A

Ｎ．Ｋａｍｅｄａ１ ｅｔ ａｌ．“Ｊ．ｏｆ Ｅｌｅｃｔｒｏｃｈｅｍ．Ｓｏｃ．”ｖｏｌ．１５４ Ｈ７６９，２００７N. Kameda1 et al. “J. of Electrochem. Soc.” Vol. 154 H769, 2007

低温で光励起オゾンを用いたＣＶＤによりゲート絶縁膜としてＳｉＯ2膜を作製すると、Ｓｉ０2の界面特性が悪い。界面特性はＴＦＴ・ＦＥＴの動作性能に大きく影響を与えるので、改善する必要がある。一方、光励起オゾンによってＳｉを直接酸化することによって作製されたＳｉＯ2膜は優れた界面特性を持つが、低温では原子拡散速度が遅いために低温５ｎｍ以上の膜厚を作製するのが困難である（特許文献１）。低温ポリシリコンＴＦＴ・ＦＥＴでは、ゲート酸化膜に必要な厚みは現在、５０〜１００ｎｍ程度なのでＣＶＤ製膜方法を適用しなければならない。 When an SiO 2 film is produced as a gate insulating film by CVD using photoexcited ozone at a low temperature, the interface characteristics of SiO 2 are poor. Since the interface characteristics greatly affect the operation performance of the TFT / FET, it is necessary to improve the interface characteristics. On the other hand, the SiO 2 film produced by directly oxidizing Si with photoexcited ozone has excellent interface characteristics, but it is difficult to produce a film thickness of 5 nm or more at a low temperature because the atomic diffusion rate is low at a low temperature. (Patent Document 1). In the low-temperature polysilicon TFT / FET, the thickness required for the gate oxide film is currently about 50 to 100 nm, so that the CVD film forming method must be applied.

そこで、ポリシリコン上に先に直接酸化による酸化膜を作製し、続けてＣＶＤプロセスを行うことで、Ｓｉ／ＳｉＯ2界面に界面特性が優れた直接酸化膜を形成し、この直接酸化膜上にＣＶＤによって製膜させる方法が考えられる。 Therefore, an oxide film by direct oxidation is first formed on polysilicon, and then a CVD process is performed to form a direct oxide film having excellent interface characteristics at the Si / SiO 2 interface. A method of forming a film by CVD is conceivable.

しかしながら、このような二段階でのプロセスでの製膜を行うにあたり、下地の直接酸化膜とＣＶＤプロセス酸化膜とＣＶＤ膜との密着性が問題となる。下地に酸化膜が存在することで、表面が水素終端されてないためにこれらの膜間の密着性がどうしても悪くなる。密着性の劣化により、両者の膜間に低密度な膜ができることにより、電荷捕獲サイトの増加、膜の誘電率の変化を引き起こすことが考えられる。   However, when forming a film in such a two-stage process, the adhesion between the underlying direct oxide film, the CVD process oxide film, and the CVD film becomes a problem. Due to the presence of the oxide film on the base, the surface is not hydrogen-terminated, and the adhesion between these films is inevitably deteriorated. It is conceivable that a low-density film is formed between the two films due to the deterioration of the adhesion, thereby causing an increase in charge trapping sites and a change in the dielectric constant of the film.

そこで、前記課題を解決するための酸化膜形成方法は、処理基板上に酸化膜を形成する酸化膜形成方法であって、処理基板に対してオゾン含有ガスのみを供給して処理基板上に酸化膜を形成する酸化工程と、この酸化工程を経た処理基板に対してＣＶＤ原料ガスとオゾン含有ガスとを供給して当該処理基板上に前記原料ガスの成分の酸化物からなる酸化膜を形成させるＣＶＤ工程を有する。   Therefore, an oxide film forming method for solving the above-mentioned problem is an oxide film forming method for forming an oxide film on a processing substrate, wherein only an ozone-containing gas is supplied to the processing substrate to oxidize the processing substrate. An oxidation process for forming a film, and a CVD source gas and an ozone-containing gas are supplied to the processing substrate that has undergone the oxidation process to form an oxide film made of an oxide of the component of the source gas on the processing substrate. It has a CVD process.

前記ＣＶＤ工程の初期段階では製膜速度を前記酸化工程の製膜速度よりも小さく制御すると、基板上の酸化膜とＣＶＤ膜との密着性がさらに高まる。前記製膜速度の態様としては、例えば、前記ＣＶＤ工程の開始直後に製膜速度を前記酸化工程の製膜速度よりも小さくし一定の時間が経過した後に所定の製膜速度に増加させる方式や、前記ＣＶＤ工程の開始直後に製膜速度０の状態から所定の製膜速度までに経時的に増加させる方式が挙げられる。前記製膜速度は、例えば、前記処理基板を含んだＣＶＤ工程に係る系の圧力、オゾン含有ガスの流量、ＣＶＤ原料ガスの流量のいずれかを調整することで制御できる。また、前記酸化工程及び前記ＣＶＤ工程では処理基板に対して紫外光領域の波長を有する光を照射すると、当該各工程におけるオゾンが励起されて酸化処理の効率が高まる。この場合、前記ＣＶＤ工程では前記光の照度を調整することで前記製膜速度を制御できる。   In the initial stage of the CVD process, when the film forming speed is controlled to be smaller than the film forming speed of the oxidizing process, the adhesion between the oxide film on the substrate and the CVD film is further increased. As an aspect of the film forming speed, for example, a method in which the film forming speed is made smaller than the film forming speed in the oxidation process immediately after the start of the CVD process, and is increased to a predetermined film forming speed after a certain time has passed. There is a method in which immediately after the start of the CVD process, the film formation rate is increased over time from a state where the film formation rate is 0 to a predetermined film formation rate. The film forming speed can be controlled, for example, by adjusting any of the pressure of the system related to the CVD process including the processing substrate, the flow rate of ozone-containing gas, and the flow rate of CVD source gas. In the oxidation process and the CVD process, when the processing substrate is irradiated with light having a wavelength in the ultraviolet region, ozone in each process is excited and the efficiency of the oxidation process is increased. In this case, the film forming speed can be controlled by adjusting the illuminance of the light in the CVD process.

また、前記ＣＶＤ工程を経た処理基板をオゾン含有ガスの雰囲気または紫外光領域の波長を有する光が照射されたオゾン含有ガスの雰囲気に曝すアニール工程と、このアニール工程を経た処理基板を前記ＣＶＤ工程に供する工程とをさらに有するようにすると、前記基板上の酸化膜とＣＶＤ膜との密着性がさらに一層高まる。そして、前記アニール工程を経た処理基板を前記ＣＶＤ工程に供する工程を複数繰り返すと、酸化膜とＣＶＤ膜との密着性が向上することに加えてＣＶＤ膜の膜質が向上する。   Further, an annealing step of exposing the treated substrate subjected to the CVD step to an ozone-containing gas atmosphere or an ozone-containing gas atmosphere irradiated with light having a wavelength in the ultraviolet region, and the treated substrate subjected to the annealing step to the CVD step In addition, the adhesion between the oxide film on the substrate and the CVD film is further enhanced. When a plurality of processes for subjecting the processed substrate subjected to the annealing process to the CVD process are repeated, in addition to improving the adhesion between the oxide film and the CVD film, the film quality of the CVD film is improved.

以上の発明によれば酸化膜とＣＶＤ膜との密着性が高まり界面特性の優れた膜の作製が実現する。   According to the above invention, the adhesion between the oxide film and the CVD film is enhanced, and the production of a film having excellent interface characteristics is realized.

発明の実施形態に係る製膜プロセス装置を示した概略構成図。The schematic block diagram which showed the film forming process apparatus which concerns on embodiment of invention. 従来技術に係る製膜プロセスで形成された半導体基板の概略構成を示した断面図。Sectional drawing which showed schematic structure of the semiconductor substrate formed by the film forming process which concerns on a prior art. 発明に係る処理チャンバの具体的な構成例を示した概略構成図。The schematic block diagram which showed the specific structural example of the processing chamber which concerns on invention. （ａ）発明に係る製膜方法の手順を示したフローチャート図，（ｂ）当該製膜方法によって処理基板に形成された酸化膜の層を示した概略断面図。(A) The flowchart figure which showed the procedure of the film forming method which concerns on invention, (b) The schematic sectional drawing which showed the layer of the oxide film formed in the process board | substrate by the said film forming method. （ａ）製膜プロセスＰ１，Ｐ２によって形成した処理基板のＳｉＯ2膜上にＡｌ電極を蒸着してなるＭＩＳキャパシタを示した概略構成図，（ｂ）前記ＭＩＳキャパシタの界面準位密度。(A) Schematic configuration diagram showing an MIS capacitor formed by depositing an Al electrode on the SiO 2 film of the processing substrate formed by the film forming processes P1 and P2, and (b) interface state density of the MIS capacitor. ＭＩＳキャパシタのＪ−Ｅ特性図。The JE characteristic figure of a MIS capacitor. 直接酸化膜層とＣＶＤ膜層との間に介在する層を示した基板の概略断面図。The schematic sectional drawing of the board | substrate which showed the layer interposed between a direct oxide film layer and a CVD film layer. Ｐ１プロセスの処理時間が０分、３分、１０分である場合の高周波（１００ＭＨｚ）Ｃ−Ｖ特性図。The high frequency (100 MHz) CV characteristic figure in case the processing time of P1 process is 0 minute, 3 minutes, and 10 minutes. 発明の実施形態２に係る製膜速度の制御のタイムスケジュールを示した図。The figure which showed the time schedule of control of the film forming speed which concerns on Embodiment 2 of invention. ＨＭＤＳガス流量の条件を変えた場合のＣ−Ｖ特性の飽和容量を示した特性図。The characteristic view which showed the saturation capacity | capacitance of the CV characteristic at the time of changing the conditions of HMDS gas flow volume. 発明の実施形態３に係る製膜プロセスの手順を示したフローチャート図。The flowchart figure which showed the procedure of the film forming process which concerns on Embodiment 3 of invention.

（実施形態１）
図１に示された発明の実施形態１に係る製膜プロセス装置１は酸化処理及びＣＶＤ処理に供される処理基板を格納する処理チャンバ２０５を備える。酸化プロセスとＣＶＤプロセスを同一チャンバ内で処理する。すなわち、処理チャンバ２０５においては処理基板に対してオゾン含有ガスのみが供給されて処理基板上に酸化膜を形成する酸化工程が実行される。次いで、この工程を経た処理基板に対してＣＶＤ原料ガスとオゾン含有ガスとを供給されて当該処理基板上に前記原料ガスの成分の酸化物からなる酸化膜を形成させるＣＶＤ工程が実行される。尚、酸化の対象の処理基板はＳｉ以外でも構わない。例えばアルミ酸化が挙げられる。 (Embodiment 1)
The film forming process apparatus 1 according to the first embodiment of the invention shown in FIG. 1 includes a processing chamber 205 that stores a processing substrate to be subjected to an oxidation process and a CVD process. The oxidation process and the CVD process are processed in the same chamber. That is, in the processing chamber 205, only an ozone-containing gas is supplied to the processing substrate, and an oxidation process for forming an oxide film on the processing substrate is performed. Next, a CVD process is performed in which a CVD source gas and an ozone-containing gas are supplied to the process substrate that has undergone this process to form an oxide film made of an oxide of the component of the source gas on the process substrate. The processing substrate to be oxidized may be other than Si. An example is aluminum oxidation.

上記酸化工程およびＣＶＤ工程に用いるオゾン含有ガスはオゾン供給装置２０１から供給される。オゾン供給装置２０１にはオゾン発生機またはオゾンガスを充填したボンベが適用される。オゾン含有ガスのオゾン濃度は１〜１００％とする。オゾン濃度１００％のオゾンガスとしては例えば特公平５−１７１６４に示されたオゾンビーム発生装置から得られたオゾンガスが挙げられる。   The ozone-containing gas used in the oxidation process and the CVD process is supplied from an ozone supply device 201. An ozone generator or a cylinder filled with ozone gas is applied to the ozone supply device 201. The ozone concentration of the ozone-containing gas is 1 to 100%. Examples of ozone gas having an ozone concentration of 100% include ozone gas obtained from an ozone beam generator shown in Japanese Patent Publication No. 5-17164.

ＣＶＤに用いられる原料ガスは原料ガス供給装置２０２から供給される。原料ガスとしてはＨＭＤＳ、ＴＥＯＳが例示される有機シリコン系のガスが挙げられる。原料ガス供給装置２０２には前記原料ガスの発生機またはボンベが適用される。尚、ＣＶＤ工程ではＳｉＯ2以外の膜作製でも構わない。例えば、ＨｆＯ2酸化膜、Ｓｉ3Ｎ4膜が挙げられる。 A source gas used for CVD is supplied from a source gas supply device 202. Examples of the source gas include organic silicon-based gases such as HMDS and TEOS. The source gas generator 202 or the cylinder is applied to the source gas supply device 202. In the CVD process, a film other than SiO 2 may be formed. For example, a HfO 2 oxide film and a Si 3 N 4 film can be used.

供給装置２０１，２０２から供されたガスはそれぞれ真空対応（＜０．１Ｐａ）の配管２１１，２１２を介して処理チャンバ２０５へ供給するようにする。配管２１１，２１２には流量を調節するバルブＶ０１，Ｖ０２が設置する。   Gases supplied from the supply devices 201 and 202 are supplied to the processing chamber 205 via pipings 211 and 212 corresponding to vacuum (<0.1 Pa), respectively. Valves V01 and V02 for adjusting the flow rate are installed in the pipes 211 and 212, respectively.

処理チャンバ２０５に供された処理済みのオゾンガス及び原料ガスは配管２１３を介して排気ポンプ２０７によって排気される。配管２１３にも流量可変バルブまたは開閉バルブ等に例示されるバルブＶ０３が設置される。   The treated ozone gas and raw material gas supplied to the processing chamber 205 are exhausted by the exhaust pump 207 through the pipe 213. The pipe 213 is also provided with a valve V03 exemplified as a variable flow rate valve or an open / close valve.

配管２１１はオゾンが通過するときにオゾン分解を抑えるため、配管２１１の内面を研磨などでオゾン分解を防止する処理が適宜に施される。配管２１２，２１３及び処理チャンバ２０５は室温よりも高くても構わない。すなわち、前記原料ガスとして例えばＴＥＯＳのような低い蒸気圧のガスを用いる場合、配管２１２、処理チャンバ２０５、配管２１３での前記ガスの液化を防ぐために当該配管及びチャンバに加熱機構が具備される。   In order to suppress ozone decomposition when the ozone passes through the pipe 211, a process for preventing ozone decomposition by polishing the inner surface of the pipe 211 is appropriately performed. The pipes 212 and 213 and the processing chamber 205 may be higher than room temperature. That is, when a low vapor pressure gas such as TEOS is used as the source gas, a heating mechanism is provided in the pipe and the chamber in order to prevent liquefaction of the gas in the pipe 212, the processing chamber 205, and the pipe 213.

図３を参照しながら処理チャンバの具体的な構成例について説明する。   A specific configuration example of the processing chamber will be described with reference to FIG.

図３に示された処理チャンバ２０５は配管２１１〜２１３を天井部にそれぞれ一つ以上接続させている。もしオゾンガスと原料ガスとを処理チャンバ２０５よりも上流側で合流させる場合はオゾンガスと原料ガスの混合ガスを導入するための配管が一つのみ接続される。処理チャンバ２０５には必要に応じてパージ用ガスを導入するための配管２１４を設けてもよい。また、処理チャンバ２０５の端部には処理基板用の出入り口２１５が一つ以上設けられる。   The processing chamber 205 shown in FIG. 3 has one or more pipes 211 to 213 connected to the ceiling. If the ozone gas and the source gas are merged upstream of the processing chamber 205, only one pipe for introducing a mixed gas of the ozone gas and the source gas is connected. The processing chamber 205 may be provided with a pipe 214 for introducing a purge gas as necessary. In addition, at least one entrance / exit 215 for the processing substrate is provided at the end of the processing chamber 205.

処理チャンバ２０５は真空対応の炉となるように形成される。チャンバの到達圧力は０．０１Ｐａ程度である。オゾン処理炉２０５には圧力計２２１を設けるのが望ましい。圧力計２２１の仕様は測定範囲圧力が０．０１Ｐａ〜１００００Ｐａであるものを採用するとよい。処理チャンバ２０５の炉壁を構成する材料としてはアルミ・ＳＵＳ・石英ガラスに例示される０．１Ｐａまでの真空状態での使用が可能で酸化しにくい材料が採用される。   The processing chamber 205 is formed to be a vacuum-compatible furnace. The ultimate pressure of the chamber is about 0.01 Pa. It is desirable to provide a pressure gauge 221 in the ozone treatment furnace 205. The specification of the pressure gauge 221 may employ a measurement range pressure of 0.01 Pa to 10000 Pa. As a material constituting the furnace wall of the processing chamber 205, a material that can be used in a vacuum state up to 0.1 Pa exemplified by aluminum, SUS, and quartz glass and is not easily oxidized is adopted.

また、処理チャンバ２０５にて光オゾン酸化・光オゾンＣＶＤを行う場合、当該酸化、ＣＶＤに供される紫外光を処理基板２２２に照射するための紫外光源２０３が処理チャンバ２０５の外に設置される。紫外光源２０３の紫外光が処理基板２２２に供されるように処理チャンバ２０５には照射窓２０４が具備される。照射窓２０４の材質は２００〜３００ｎｍの光を透過するものを用いる（例えば、石英ガラス、ＭｇＦ2など）。紫外光源２０３には少なくとも波長２００〜３００ｎｍの光を含む光を照射する周知の光源を適用すればよい。また、紫外光源２０３と透過窓２０４との間にシャッター２０６設置する。シャッター２０６は開閉可能とし、プロセス前後で開閉を行えるようにする。透過窓２０４の材質として少なくとも波長２００〜３００ｎｍの光を吸収もしくは反射する材質が採用される（例えばＡｌ）。 Further, when performing photo-ozone oxidation / photo-ozone CVD in the processing chamber 205, an ultraviolet light source 203 for irradiating the processing substrate 222 with ultraviolet light to be used for the oxidation and CVD is installed outside the processing chamber 205. . The processing chamber 205 is provided with an irradiation window 204 so that the ultraviolet light from the ultraviolet light source 203 is supplied to the processing substrate 222. The irradiation window 204 is made of a material that transmits light of 200 to 300 nm (for example, quartz glass, MgF 2, etc.). As the ultraviolet light source 203, a known light source that emits light including light having a wavelength of at least 200 to 300 nm may be applied. A shutter 206 is installed between the ultraviolet light source 203 and the transmission window 204. The shutter 206 can be opened and closed so that it can be opened and closed before and after the process. A material that absorbs or reflects at least light having a wavelength of 200 to 300 nm is employed as the material of the transmission window 204 (for example, Al).

処理基板２２２はその表面に紫外光源２０３の光が直接当たるように処理チャンバ２０５に格納される。処理基板２２２はサセプタ２２３上に保持されている。サセプタ２２３は回転機構や搬送機構によって処理チャンバ２０５内を移動可能なるように設置される。サセプタ２２３は必要に応じ加熱機構によって加熱可能とするとよい。   The processing substrate 222 is stored in the processing chamber 205 so that the light of the ultraviolet light source 203 directly hits the surface of the processing substrate 222. The processing substrate 222 is held on the susceptor 223. The susceptor 223 is installed so as to be movable in the processing chamber 205 by a rotation mechanism or a transport mechanism. The susceptor 223 may be heated by a heating mechanism as necessary.

酸化工程及びＣＶＤ工程においては、共有するプロセス条件（オゾン供給量、ＣＶＤ原料ガス供給量、プロセス圧力、紫外光光源２０３の光照射量、プロセス温度（例えばサセプタ２２３の温度）、排気速度（例えば排気ポンプ２０７の排気速度））が適宜制御される。   In the oxidation process and the CVD process, shared process conditions (ozone supply amount, CVD source gas supply amount, process pressure, light irradiation amount of the ultraviolet light source 203, process temperature (for example, the temperature of the susceptor 223), and exhaust speed (for example, exhaust) The pumping speed of the pump 207)) is appropriately controlled.

図４を参照しながら本実施形態に係る製膜方法についてより具体的に説明する。   The film forming method according to the present embodiment will be described more specifically with reference to FIG.

本実施形態の製膜方法は図４（ａ）に示すように大きく２つの段階からなる。すなわち、処理基板に対してオゾンガスのみを供して直接酸化を行う製膜プロセスＰ１と、このプロセスを経た処理基板に対してＣＶＤ原料ガスとオゾンガスとを供してＣＶＤを行う製膜プロセスＰ２とからなる。プロセスは一貫して４００℃以下の低温で行われる。   As shown in FIG. 4A, the film forming method of the present embodiment is roughly composed of two stages. That is, it comprises a film forming process P1 in which only the ozone gas is supplied to the processing substrate to directly oxidize, and a film forming process P2 in which the CVD source gas and the ozone gas are supplied to the processing substrate having undergone this process to perform the CVD. . The process is consistently performed at low temperatures below 400 ° C.

製造プロセスＰ１では処理チャンバ２０５内にオゾン含有ガスのみが供給され、ＣＶＤ原料ガスは供給しない。ガス流を制御するために、窒素やアルゴンなどの不活性ガスを導入してもよい。光オゾンによる酸化を用いる場合、紫外光源２０３から基板へ光を供給する。   In the manufacturing process P1, only the ozone-containing gas is supplied into the processing chamber 205, and the CVD source gas is not supplied. In order to control the gas flow, an inert gas such as nitrogen or argon may be introduced. When using oxidation by light ozone, light is supplied from the ultraviolet light source 203 to the substrate.

製造プロセスＰ２ではオゾン含有ガスとＣＶＤ原料ガスとがチャンバ２０５に供給される。ガス流を制御するために、窒素やアルゴンなどの不活性ガスを導入することは問題ない。光ＣＶＤによる製膜の場合、紫外光源２０３から処理基板２２２へ光を供給する。   In the manufacturing process P2, the ozone-containing gas and the CVD source gas are supplied to the chamber 205. There is no problem in introducing an inert gas such as nitrogen or argon in order to control the gas flow. In the case of film formation by optical CVD, light is supplied from the ultraviolet light source 203 to the processing substrate 222.

酸化プロセスＰ１とＣＶＤ製膜プロセスＰ２において、プロセス圧力、オゾン流量、光照射量、光照射波長、光照射領域は相違していてもよい。   In the oxidation process P1 and the CVD film forming process P2, the process pressure, the ozone flow rate, the light irradiation amount, the light irradiation wavelength, and the light irradiation region may be different.

以上の製膜プロセスＰ１，Ｐ２を経ることで図４（ｂ）のような膜構造を形成できる。基板３０１の上には製膜プロセスＰ１により作製された酸化膜３０２が存在し、酸化膜３０２の上に製膜プロセスＰ２により作製された酸化膜３０３が存在する。   A film structure as shown in FIG. 4B can be formed through the film forming processes P1 and P2. An oxide film 302 produced by the film production process P1 exists on the substrate 301, and an oxide film 303 produced by the film production process P2 exists on the oxide film 302.

製膜プロセスＰ１，Ｐ２ともにプロセス圧力はオゾンの爆発限界以下の範囲とする。また、光源２０３からの供給される光の紫外光２００〜３００ｎｍ成分は光子数換算で、オゾン分子密度よりも十分に大きい範囲の出力とする。光源２０３はレーザーによるパルス型発振型またはランプによる連続照射型どちらでもよい。ＣＶＤ原料ガスは、例えばＳｉＯ2膜を作製する場合、ＨＭＤＳやＴＥＯＳなどＳｉを含むものとする。室温では蒸気圧が低いＴＥＯＳでは、ガス供給系の配管を７０℃程度に加熱するとよい。ＨＭＤＳ及びＴＥＯＳガス流量は、オゾン流量に対して十分小さい範囲とする。これは原料ガス１分子に対し、分解に必要なオゾン分子が多数個必要であるため。真空下であれば、製膜プロセスＰ１，Ｐ２の間に中断時間を設けてもよい。 In both the film forming processes P1 and P2, the process pressure is set to a range below the explosion limit of ozone. Further, the ultraviolet light 200 to 300 nm component of the light supplied from the light source 203 is an output in a range sufficiently larger than the ozone molecule density in terms of the number of photons. The light source 203 may be either a pulsed oscillation type using a laser or a continuous irradiation type using a lamp. The CVD source gas includes Si such as HMDS and TEOS when, for example, an SiO 2 film is formed. In TEOS, which has a low vapor pressure at room temperature, the gas supply system piping may be heated to about 70 ° C. The HMDS and TEOS gas flow rates are in a sufficiently small range with respect to the ozone flow rate. This is because a large number of ozone molecules are required for decomposition for each molecule of source gas. If under vacuum, an interruption time may be provided between the film forming processes P1 and P2.

製膜プロセスＰ１，Ｐ２をそれぞれ別チャンバで行っても構わない。その場合、チャンバ間を真空雰囲気下で搬送するようにする。製膜プロセスＰ１と製膜プロセスＰ２を別チャンバにすることにより、製膜プロセスＰ２で発生するパーティクルが製膜プロセスＰ１に与える影響を小さくすることができる。また、製膜プロセスＰ１と製膜プロセスＰ２の処理チャンバを別にすることで、それぞれのプロセスの特徴に応じたチャンバにて製膜できることから、効率的に行うことができる。例えば製膜プロセスＰ１においてはチャンバ内の光炉長（ギャップ長）を短くしたものを用いることにより、プロセスＰ１の処理時間を短くすることが可能となる。   The film forming processes P1 and P2 may be performed in separate chambers. In that case, the chamber is transported in a vacuum atmosphere. By making the film forming process P1 and the film forming process P2 into separate chambers, the influence of particles generated in the film forming process P2 on the film forming process P1 can be reduced. Further, by separating the processing chambers of the film forming process P1 and the film forming process P2, film formation can be performed in chambers according to the characteristics of the respective processes, so that it can be performed efficiently. For example, in the film forming process P1, it is possible to shorten the processing time of the process P1 by using the one having a shortened optical furnace length (gap length) in the chamber.

次に本実施形態の実施例について説明する。本実施例ではＳｉウエハ上にＳｉＯ2膜を製膜した。製膜プロセスＰ１では光オゾン酸化プロセスを実施した。処理基板はＳｉ（１００）とした。オゾン含有ガスはオゾン濃度９０％以上のものを用いてその流量は約１００ｓｃｃｍに設定した。製膜プロセスＰ１に係る光源には高圧水銀ランプを採用した。基板温度は１００℃、プロセスＰ１の処理時間は１０分以下、プロセスＰ１で作製される膜の膜厚は３ｎｍ以下に制御した。 Next, examples of the present embodiment will be described. In this example, a SiO 2 film was formed on a Si wafer. In the film forming process P1, a photo-ozone oxidation process was performed. The treatment substrate was Si (100). An ozone-containing gas having an ozone concentration of 90% or more was used, and its flow rate was set to about 100 sccm. A high pressure mercury lamp was employed as the light source for the film forming process P1. The substrate temperature was controlled to 100 ° C., the processing time of the process P1 was 10 minutes or less, and the film thickness of the film produced by the process P1 was controlled to 3 nm or less.

製膜プロセスＰ１の後、同じチャンバで同じ光源を用いた製膜プロセスＰ２を開始した。製膜プロセスＰ２では光励起オゾンＣＶＤを実施した。ＣＶＤ原料ガスにはＨＭＤＳを使用した。オゾン含有ガスは製膜プロセスＰ１と同じ濃度で使用した。オゾン含有ガスの流量は約１００ｓｃｃｍ、ＨＭＤＳの流量は１ｓｃｃｍ、処理時間は８分、膜厚は５０ｎｍ程度、基板温度は１００℃に設定した。   After the film forming process P1, a film forming process P2 using the same light source in the same chamber was started. In the film forming process P2, photoexcited ozone CVD was performed. HMDS was used as the CVD source gas. The ozone-containing gas was used at the same concentration as in the film forming process P1. The flow rate of the ozone-containing gas was about 100 sccm, the flow rate of HMDS was 1 sccm, the processing time was 8 minutes, the film thickness was about 50 nm, and the substrate temperature was set to 100 ° C.

上記の条件で作製された処理基板に製膜されたＳｉＯ2の界面特性結果を図５に示す。図５（ａ）に示したように、製膜プロセスＰ１，Ｐ２の後、Ｓｉ（１００）からなる処理基板４０１にＳｉＯ2膜４０３上にＡｌ電極４０４を蒸着してＭＩＳキャパシタを形成した。図示されたＳｉＯ２膜４０２，４０３はそれぞれ製膜プロセスＰ１，Ｐ２で得られた酸化膜である。図５（ｂ）はｑｕａｓｉ−ｓｔａｔｉｃ法によるＣ−Ｖ測定から算出された界面準位密度を示す。Ａｌ電極４０４の蒸着後にＡｌとＳｉＯ2膜との密着性を高めるために、ＰＭＡアニールを０．１ａｔｍのＮ2雰囲気下４００℃で２０分行っている。製膜プロセスＰ１の処理時間（酸化処理時間）を０分、３分、１０分とした場合の界面順位密度を開示した。製膜プロセスＰ１の処理時間が大きくなると界面準位密度の最小値が減少し、ギャップ幅も大きくなることから、界面特性が大幅に改善されている。つまり、この結果は、製膜プロセスＰ１を行うことにより、界面特性が改善できていることを示している。 FIG. 5 shows the results of the interface characteristics of SiO 2 formed on the processing substrate manufactured under the above conditions. As shown in FIG. 5A, after the film forming processes P1 and P2, an Al electrode 404 was deposited on the SiO 2 film 403 on the processing substrate 401 made of Si (100) to form a MIS capacitor. The illustrated SiO 2 films 402 and 403 are oxide films obtained by the film forming processes P 1 and P 2, respectively. FIG. 5B shows the interface state density calculated from the CV measurement by the quasi-static method. In order to enhance the adhesion between the Al and SiO 2 film after the deposition of the Al electrode 404, PMA annealing is performed at 400 ° C. for 20 minutes in an N 2 atmosphere of 0.1 atm. The interfacial order density was disclosed when the processing time (oxidation processing time) of the film forming process P1 was 0 minutes, 3 minutes, and 10 minutes. When the processing time of the film forming process P1 is increased, the minimum value of the interface state density is decreased and the gap width is also increased, so that the interface characteristics are greatly improved. That is, this result shows that the interface characteristics can be improved by performing the film forming process P1.

一方、絶縁特性のような膜全体で決まる特性は製膜プロセスＰ１の影響をほとんど受けない。図６はＭＩＳキャパシタ配置におけるＪ−Ｅ特性である。酸化処理時間が異なる製膜プロセスＰ１（処理時間０分、３分、１０分）で形成されたキャパシタのＪ−Ｅ特性を比較すると、差異がほとんどみられなかった。これは製膜プロセスＰ１で作製された膜厚が３ｎｍ以下に対し製膜プロセスＰ２で作製された膜厚が５０ｎｍであるので、製膜プロセスＰ２で作製された膜が全体膜厚の大部分を占めることにより、膜全体の特性によってきまる膜質は、製膜プロセスＰ１の時間の長さにほとんど影響を受けないことを示している。   On the other hand, characteristics determined by the entire film such as insulating characteristics are hardly affected by the film forming process P1. FIG. 6 shows JE characteristics in the MIS capacitor arrangement. When comparing the J-E characteristics of the capacitors formed by the film forming process P1 (treatment time 0 minutes, 3 minutes, 10 minutes) with different oxidation treatment times, almost no difference was observed. This is because the film thickness produced by the film production process P1 is 50 nm while the film thickness produced by the film production process P2 is 50 nm while the film thickness produced by the film production process P1 is 50 nm or less. It shows that the film quality determined by the characteristics of the entire film is hardly affected by the length of time of the film forming process P1.

以上の例により、実際に界面を改善できることを示した。プロセス条件について特に制限を設けないが実用的なプロセスとして、製膜プロセスＰ１，Ｐ２ともオゾン流量は１〜１０００ｓｃｃｍの範囲、Ｓｉ酸化及びＣＶＤプロセスに用いるオゾンの分圧は０．１〜１０００Ｐａの範囲内、製膜プロセスＰ１，Ｐ２に用いる２００〜３００ｎｍの光照射量は、１〜１０００ｍＷ／ｃｍ2の範囲である。また、製膜プロセスＰ２に用いるＨＭＤＳガスは１〜１００ｓｃｃｍであり、製膜プロセスＰ１の処理時間は、０．１秒〜１時間程度である。 The above example shows that the interface can actually be improved. Although there is no particular limitation on the process conditions, as a practical process, the ozone flow rate in the film forming processes P1 and P2 is in the range of 1 to 1000 sccm, and the partial pressure of ozone used in the Si oxidation and CVD processes is in the range of 0.1 to 1000 Pa. Among them, the light irradiation amount of 200 to 300 nm used for the film forming processes P1 and P2 is in the range of 1 to 1000 mW / cm 2 . The HMDS gas used for the film forming process P2 is 1 to 100 sccm, and the processing time of the film forming process P1 is about 0.1 second to 1 hour.

以上説明したように実施形態１の製膜プロセス装置１によれば界面特性が優れた酸化膜を作製することができる。また、４００℃以下の低温で酸化膜を作製することができる。波長２００〜３００ｎｍの光源を併用することで、２００℃以下の低温で酸化膜を製膜することができる。１００ｎｍ以上の厚い膜を作ることができる。   As described above, according to the film forming process apparatus 1 of the first embodiment, an oxide film having excellent interface characteristics can be produced. In addition, an oxide film can be formed at a low temperature of 400 ° C. or lower. By using a light source having a wavelength of 200 to 300 nm in combination, an oxide film can be formed at a low temperature of 200 ° C. or lower. A thick film of 100 nm or more can be formed.

酸化プロセス（Ｐ１）、ＣＶＤプロセス（Ｐ２）は別チャンバで実行してもよい。酸化プロセスチャンバとＣＶＤプロセスチャンバとの間の輸送は１Ｐａ以下の真空度の環境で行われる。このようにプロセスＰ１、プロセスＰ２を個別の系で実行することで、酸化プロセスにおけるパーティクルの混入を減らすことができ、より界面特性の優れた膜の作製が可能となる。そして、酸化プロセスにおける製膜速度が上昇することで、酸化プロセス処理時間の短縮が実現する。   The oxidation process (P1) and the CVD process (P2) may be performed in separate chambers. Transport between the oxidation process chamber and the CVD process chamber is performed in an environment having a vacuum degree of 1 Pa or less. As described above, by executing the process P1 and the process P2 in separate systems, the mixing of particles in the oxidation process can be reduced, and a film having better interface characteristics can be produced. And the film-forming speed | rate in an oxidation process rises, and shortening of an oxidation process processing time is implement | achieved.

（実施形態２）
二段階でのプロセスでの製膜を行うにあたり、下地の直接酸化膜とＣＶＤプロセス酸化膜とＣＶＤ膜との密着性が問題となる。ＣＶＤプロセスを始めるときに下地に酸化膜が存在するために、通常の水素終端された表面でないため界面の密着性がどうしても悪くなる。この密着性の劣化により、両者の膜間に低密度な膜ができてしまい、電荷捕獲サイトの増加、膜の誘電率の変化を引き起こすことが考えられる。つまり、図７に示したように基板３０１上に直接酸化膜３０２があるときにＣＶＤ膜３０３を形成しようとすると膜３０２と膜３０３との間に密度が低い層３０４ができてしまう。 (Embodiment 2)
In film formation in a two-stage process, the adhesion between the underlying direct oxide film, the CVD process oxide film, and the CVD film becomes a problem. Since an oxide film is present in the base when starting the CVD process, the adhesion at the interface is inevitably deteriorated because it is not a normal hydrogen-terminated surface. It is considered that due to this deterioration in adhesion, a low-density film is formed between the two films, causing an increase in charge trapping sites and a change in the dielectric constant of the film. That is, as shown in FIG. 7, when the CVD film 303 is formed when the oxide film 302 is directly on the substrate 301, a low-density layer 304 is formed between the film 302 and the film 303.

二段階製膜を行うと避けられない問題として、両者の膜の密着性の問題がある。これは図７で示した膜３０４の存在に相当する。膜３０４の存在は図８のＣ−Ｖ特性の飽和容量からわかる。図８はＰ１プロセスの処理時間を０分、３分、１０分とした場合の高周波（１００ＭＨｚ）Ｃ−Ｖ曲線である。製膜プロセスＰ１の処理時間が０分である場合の飽和容量ＣOX（８０１）に対して、処理時間が３分、１０分である場合の飽和容量ＣOX（８０２）減少している。これは、膜の誘電率が変化したために起こる。この変化量ΔＣOX（８０２）は、製膜プロセスＰ１による膜３０２の誘電率ε１（約３．９）とＣＶＤ膜３０３の誘電率ε２（約５．７）の膜厚割合の変化では説明ができず、膜３０２と膜３０３の間に低密度で真空に近い誘電率（約１）を持つ層３０４を仮定しなければ説明できないことから、膜３０４の存在が示唆される。尚、層３０４の厚みは１ｎｍ以下である。膜３０４はプロセスＰ２の開始直後にできると考えられる。 As an inevitable problem when performing two-stage film formation, there is a problem of adhesion between the two films. This corresponds to the presence of the film 304 shown in FIG. The presence of the film 304 can be seen from the saturation capacity of the CV characteristic of FIG. FIG. 8 is a high-frequency (100 MHz) CV curve when the processing time of the P1 process is 0 minutes, 3 minutes, and 10 minutes. The saturated capacity C OX (802) is decreased when the processing time is 3 minutes and 10 minutes, compared to the saturated capacity C OX (801) when the processing time of the film forming process P1 is 0 minutes. This occurs because the dielectric constant of the film has changed. This change ΔC OX (802) is explained by the change in the film thickness ratio between the dielectric constant ε1 (about 3.9) of the film 302 and the dielectric constant ε2 (about 5.7) of the CVD film 303 by the film forming process P1. This cannot be explained unless a layer 304 having a low-density, near-vacuum dielectric constant (about 1) is assumed between the film 302 and the film 303, suggesting the presence of the film 304. Note that the thickness of the layer 304 is 1 nm or less. It is thought that the film 304 can be formed immediately after the start of the process P2.

そこで、実施形態２では、製膜プロセスＰ２において、製膜速度をプロセス内で変化をつけるようし、プロセス開始直後の製膜速度を小さくすることで解決ができる。製膜プロセスの制御の態様としては図９に例示したようにスケジュールＳ１，Ｓ２が挙げられる。スケジュールＳ１は製膜プロセスＰ２の開始直後に製膜速度を製膜プロセスＰ１よりも小さくし一定の時間が経過した後に所定の製膜速度までに増加させる。スケジュールＳ２は製膜プロセスＰ２の開始直後に製膜速度０の状態から時間経過とともに所定の製膜速度までに徐々に増加させる。以上のように製膜プロセスＰ２の初期の製膜速度を製膜プロセスＰ１の製膜速度よりも小さくすることで直接酸化膜とＣＶＤ膜との間の膜密度を高めることができる。製膜速度は、基板温度以外に、処理チャンバの圧力、オゾン含有ガス流量、ＣＶＤガス流量、光源の光照度（光ＣＶＤの場合）、ガス流速を変化させることで制御できる。   Therefore, in the second embodiment, the film forming process P2 can be solved by changing the film forming speed in the process and reducing the film forming speed immediately after the start of the process. As an aspect of controlling the film forming process, schedules S1 and S2 are exemplified as illustrated in FIG. In the schedule S1, the film forming speed is made smaller than the film forming process P1 immediately after the start of the film forming process P2, and is increased to a predetermined film forming speed after a predetermined time has elapsed. The schedule S2 is gradually increased from the state of the film forming speed 0 to the predetermined film forming speed as time passes immediately after the start of the film forming process P2. As described above, the film density between the direct oxide film and the CVD film can be increased by making the initial film forming speed of the film forming process P2 smaller than the film forming speed of the film forming process P1. In addition to the substrate temperature, the film forming speed can be controlled by changing the pressure in the processing chamber, the ozone-containing gas flow rate, the CVD gas flow rate, the light intensity of the light source (in the case of optical CVD), and the gas flow rate.

本実施形態の実施例として二段階製膜において密着性を高めた実施例について説明する。   As an example of this embodiment, an example in which adhesion is improved in the two-stage film formation will be described.

本実施例はＳｉウエハ上にＳｉＯ2膜を作製した例である。製膜プロセスＰ１では光オゾン直接酸化を行った。処理基板にはＳｉ（１００）を採用した。オゾン含有ガスはオゾン濃度９０％以上、ガス流量は〜１００ｓｃｃｍ、直接酸化に供する光源には高圧水銀ランプを採用した。基板温度は１００℃、プロセスｐ１の処理時間は１０分、作製される膜厚は３ｎｍ程度に制御した。製膜プロセスＰ１の後、同じチャンバで同じ光源を用いて製膜プロセスＰ２を開始した。製膜プロセスＰ２では光励起オゾンＣＶＤを実施した。ＣＶＤ原料ガスにＨＭＤＳを使用した。オゾン含有ガスは製膜プロセスＰ１と同じ濃度で使用した。オゾン流量は約１００ｓｃｃｍに設定した。ＨＭＤＳの流量は０．１〜１ｓｃｃｍに設定した。製膜プロセスＰ２の処理時間は８〜１８分である。膜厚は５０ｎｍ程度である。基板温度は１００℃に設定した。 In this example, an SiO 2 film is formed on a Si wafer. In the film forming process P1, direct photo-ozone oxidation was performed. Si (100) was adopted as the processing substrate. The ozone-containing gas has an ozone concentration of 90% or more, the gas flow rate is ˜100 sccm, and a high-pressure mercury lamp is used as a light source for direct oxidation. The substrate temperature was controlled to 100 ° C., the processing time of the process p1 was 10 minutes, and the film thickness to be produced was controlled to about 3 nm. After the film forming process P1, the film forming process P2 was started using the same light source in the same chamber. In the film forming process P2, photoexcited ozone CVD was performed. HMDS was used as the CVD source gas. The ozone-containing gas was used at the same concentration as in the film forming process P1. The ozone flow rate was set to about 100 sccm. The flow rate of HMDS was set to 0.1-1 sccm. The processing time of the film forming process P2 is 8 to 18 minutes. The film thickness is about 50 nm. The substrate temperature was set to 100 ° C.

製膜プロセスＰ２では製膜速度を変えるために以下の条件１〜４でＨＭＤＳガス流量を変えた。
条件１：開始後１分までＨＭＤＳ流量０．１ｓｃｃｍ、その後８分間１ｓｃｃｍ。
条件２：開始後１０分までＨＭＤＳ流量０．１ｓｃｃｍ、その後８分間１ｓｃｃｍ。
条件３：開始直後からＨＭＤＳ流量１ｓｃｃｍ８分間。
条件４：製膜プロセスＰ１を行わないでプロセスＰ２として開始直後からＨＭＤＳ流量１ｓｃｃｍ８分間のＣＶＤ。 In the film forming process P2, the HMDS gas flow rate was changed under the following conditions 1 to 4 in order to change the film forming speed.
Condition 1: HMDS flow rate 0.1 sccm until 1 minute after the start, then 1 sccm for 8 minutes.
Condition 2: HMDS flow rate 0.1 sccm up to 10 minutes after start, then 1 sccm for 8 minutes.
Condition 3: HMDS flow rate 1 sccm for 8 minutes immediately after the start.
Condition 4: CVD with a HMDS flow rate of 1 sccm for 8 minutes immediately after the start as the process P2 without performing the film forming process P1.

以上の４条件におけるＣ−Ｖ特性を示す飽和容量曲線を比較した。   The saturation capacity curves showing the CV characteristics under the above four conditions were compared.

それぞれの飽和容量は図１０において条件１〜４に対して飽和容量曲線（以下、曲線とと称する）１００１〜１００４に対応する。まず条件４の曲線１００４が一番小さい。これは製膜プロセスＰ１がないことで膜３０４が存在しないことに相当する。一方、曲線１００３が一番大きい。これは膜３０４による影響を上記４条件の中でもっとも大きく置けていることを意味する。一分間ＣＶＤ製膜速度を落とした膜の曲線１００１は曲線１００３よりも曲線１００４に近づく。更に１０分間ＣＶＤ製膜速度を落とした膜の曲線１００２は曲線１００１よりも曲線１００４に近づいていることから、初期の製膜速度をなるべく抑制することで、膜３０４をなくすように製膜できることを示すことができた。   Respective saturation capacities correspond to saturation capacity curves (hereinafter referred to as curves) 1001 to 1004 for conditions 1 to 4 in FIG. First, the curve 1004 of condition 4 is the smallest. This corresponds to the absence of the film 304 due to the absence of the film forming process P1. On the other hand, the curve 1003 is the largest. This means that the influence of the film 304 is the largest among the above four conditions. The curve 1001 of the film with the CVD deposition rate reduced for 1 minute is closer to the curve 1004 than the curve 1003. Further, since the curve 1002 of the film with the CVD deposition rate lowered for 10 minutes is closer to the curve 1004 than the curve 1001, it can be formed so as to eliminate the film 304 by suppressing the initial deposition rate as much as possible. I was able to show.

（実施形態３）
本実施形態は製膜速度の制御の他に製膜プロセスＰ２中に処理基板をオゾン含有ガスまたは光励起オゾン雰囲気に曝す時間を意図的に導入している。すなわち、処理基板をオゾン含有ガスまたは光励起オゾンガスの雰囲気に曝すオゾンアニールによって直接酸化膜とＣＶＤ膜との密着性をさらに高めさせ、ＣＶＤ膜質を向上させることできる（特許文献３）。 (Embodiment 3)
In the present embodiment, in addition to the control of the film forming speed, the time during which the processing substrate is exposed to the ozone-containing gas or the photoexcited ozone atmosphere is intentionally introduced during the film forming process P2. That is, the adhesion between the oxide film and the CVD film can be further enhanced by ozone annealing by exposing the processing substrate to an atmosphere of ozone-containing gas or photoexcited ozone gas, and the CVD film quality can be improved (Patent Document 3).

本実施形態の製膜プロセスは図１１に示したように製膜プロセスＰ１，Ｐ２における製膜プロセスＰ２（ＣＶＤ製膜）をプロセスＰ２−１とプロセスＰ２−２の２段階に分け、このプロセスＰ２−１，Ｐ２−２の間にオゾンアニールのプロセスＰ３を有している。プロセスＰ３に用いるオゾン濃度は製膜プロセスＰ１，Ｐ２に用いるオゾン含有ガスのオゾン濃度と同程度（２〜１００％）でよい。プロセスＰ３用のオゾン含有ガスは製膜プロセスＰ１，Ｐ２に供するオゾン含有ガスを適用すればよい。以上のプロセスを実行するための装置構成は図３に開示された製膜プロセス装置１と同じ構成を採ればよい。   In the film forming process of this embodiment, as shown in FIG. 11, the film forming process P2 (CVD film forming) in the film forming processes P1 and P2 is divided into two stages of a process P2-1 and a process P2-2. -1 and P2-2 have ozone annealing process P3. The ozone concentration used in the process P3 may be approximately the same (2 to 100%) as the ozone concentration of the ozone-containing gas used in the film forming processes P1 and P2. As the ozone-containing gas for the process P3, an ozone-containing gas used for the film forming processes P1 and P2 may be applied. The apparatus configuration for executing the above process may be the same as the film forming process apparatus 1 disclosed in FIG.

オゾンアニール（プロセスＰ３）ではオゾンまたは光励起オゾンのＳｉＯ2膜中の拡散長の温度依存性により、４００℃以下の低温では膜厚１〜２ｎｍのＣＶＤ膜に対して有効である（特許文献３）。 Ozone annealing (process P3) is effective for a CVD film having a thickness of 1 to 2 nm at a low temperature of 400 ° C. or lower due to the temperature dependence of the diffusion length of ozone or photoexcited ozone in the SiO 2 film (Patent Document 3). .

図１１のフローチャートにおいて、製膜プロセスＰ２−１（ＣＶＤ製膜）では、膜厚１〜２ｎｍ程度製膜しておくようにしてプロセスＰ３（アニール）を行うことで効果的になる。また、製膜プロセスＰ２−２（ＣＶＤ製膜）では、開始直後の製膜速度は小さい方が望ましい。初期膜成長速度を遅くすることでプロセスＰ３が終了したときに析出しているＳｉＯ2表面とプロセスＰ２−２により形成されるＳｉＯ2との界面状態が良くなるためである。このように製膜プロセスＰ１を経た酸化膜上に製膜プロセスＰ２によってＣＶＤ膜が少し積んだ状態でオゾンアニールすることで両者の密着性が上昇する。 In the flowchart of FIG. 11, in the film formation process P2-1 (CVD film formation), it becomes effective by performing the process P3 (annealing) so as to form a film with a film thickness of about 1 to 2 nm. In the film forming process P2-2 (CVD film forming), it is desirable that the film forming speed immediately after the start is small. Initial film interface state between the SiO 2 which process P3 is by slowing the growth rate is formed by SiO 2 surface and the processes P2-2 are precipitated when finished is because the better. As described above, the ozone adhesion is performed on the oxide film that has undergone the film forming process P1 by performing the ozone annealing in a state in which the CVD film is slightly deposited by the film forming process P2.

また、プロセスＰ３は一回以上行っても構わない。例えば、製膜プロセスＰ２をｎ回に分けて行い製膜プロセスＰ２−１〜Ｐ２−ｎとしたときに製膜プロセスＰ２−ｉと製膜プロセスＰ２−ｉ＋１（１≦ｉ≦ｎ−１）の間でプロセスＰ３を実行する態様が挙げられる。このようにプロセスＰ３を計ｎ−１回実施することで直接酸化膜とＣＶＤ製膜との密着性が向上することに加えて、製膜プロセスＰ２によって形成されたＣＶＤ膜の膜質を向上させることができる。前述のように、オゾンアニールは、製膜プロセスＰ１，Ｐ２を行うチャンバ２０５で行える。または別途、オゾンアニール用のチャンバを具備してもよい。別途チャンバでオゾンアニールを行う場合、１Ｐａ以下で搬送すると、ＣＶＤ膜の表面の劣化を防ぐことができる。   Further, the process P3 may be performed once or more. For example, when the film forming process P2 is divided into n times to form film forming processes P2-1 to P2-n, the film forming process P2-i and the film forming process P2-i + 1 (1 ≦ i ≦ n−1) A mode in which the process P3 is executed in between is mentioned. Thus, in addition to improving the adhesion between the direct oxide film and the CVD film formation by performing the process P3 n-1 times in total, the film quality of the CVD film formed by the film formation process P2 is improved. Can do. As described above, ozone annealing can be performed in the chamber 205 in which the film forming processes P1 and P2 are performed. Alternatively, a chamber for ozone annealing may be provided separately. When ozone annealing is separately performed in a chamber, the surface of the CVD film can be prevented from being deteriorated by carrying it at 1 Pa or less.

以上のように実施形態３の製膜プロセス装置によれば二段階製膜において異なるプロセスによって作られたＳｉＯ2膜の界面の密着性を向上することができる。また、基板温度を上昇させる必要がない。さらに、紫外光を用いることで密着性の効果が上昇する。また、単一の処理チャンバで複数のプロセスの実施が可能である共にオゾン含有ガスは直接酸化（製膜プロセスＰ１）ＣＶＤ（製膜プロセスＰ２−ｎ）、アニール（プロセスＰ３）の共用とすることができるので、低廉な製膜が実現する。 As described above, according to the film forming process apparatus of Embodiment 3, it is possible to improve the adhesion at the interface of the SiO 2 film formed by different processes in the two-stage film forming. Further, there is no need to increase the substrate temperature. Further, the adhesion effect is increased by using ultraviolet light. In addition, a plurality of processes can be performed in a single processing chamber, and the ozone-containing gas is shared by direct oxidation (film formation process P1), CVD (film formation process P2-n), and annealing (process P3). Therefore, inexpensive film formation is realized.

１…製膜プロセス装置
２０１…オゾン供給装置
２０２…原料ガス供給装置
２０３…紫外光源
２０５…処理チャンバ DESCRIPTION OF SYMBOLS 1 ... Film forming process apparatus 201 ... Ozone supply apparatus 202 ... Raw material gas supply apparatus 203 ... Ultraviolet light source 205 ... Processing chamber

Claims (9)

処理基板上に酸化膜を形成する酸化膜形成方法であって、
処理基板に対してオゾン含有ガスのみを供給して処理基板上に酸化膜を形成する酸化工程と、
この酸化工程を経た処理基板に対してＣＶＤ原料ガスとオゾン含有ガスとを供給して当該処理基板上に前記原料ガスの成分の酸化物からなる酸化膜を形成させるＣＶＤ工程と
を有すること
を特徴とする酸化膜形成方法。 An oxide film forming method for forming an oxide film on a processing substrate,
An oxidation step in which only an ozone-containing gas is supplied to the processing substrate to form an oxide film on the processing substrate;
A CVD step of supplying a CVD source gas and an ozone-containing gas to the processing substrate that has undergone the oxidation step to form an oxide film made of an oxide of the component of the source gas on the processing substrate. An oxide film forming method. 前記ＣＶＤ工程の初期段階の製膜速度を前記酸化工程の製膜速度よりも小さく制御することを特徴とする請求項１に記載の酸化膜形成方法。   The method for forming an oxide film according to claim 1, wherein a film forming speed in an initial stage of the CVD process is controlled to be smaller than a film forming speed in the oxidizing process. 前記ＣＶＤ工程の開始直後に製膜速度を前記酸化工程の製膜速度よりも小さくし一定の時間が経過した後に所定の製膜速度に増加させることを特徴とする請求項２に記載の酸化膜形成方法。   3. The oxide film according to claim 2, wherein immediately after the start of the CVD process, the film forming speed is made smaller than the film forming speed of the oxidation process and is increased to a predetermined film forming speed after a predetermined time has elapsed. Forming method. 前記ＣＶＤ工程の開始直後に製膜速度０の状態から所定の製膜速度までに経時的に増加させることを特徴とする請求項２に記載の酸化膜形成方法。   3. The method of forming an oxide film according to claim 2, wherein immediately after the start of the CVD process, the time is increased over time from a state where the film forming speed is zero to a predetermined film forming speed. 前記製膜速度は前記処理基板を含んだＣＶＤ工程に係る系の圧力、オゾン含有ガスの流量、ＣＶＤ原料ガスの流量のいずれかを調整することにより制御すること
を特徴とする請求項３または４に記載の酸化膜形成方法。 5. The film forming speed is controlled by adjusting any one of a system pressure, a flow rate of an ozone-containing gas, and a flow rate of a CVD source gas related to a CVD process including the processing substrate. The method for forming an oxide film as described in 1. above. 前記酸化工程及び前記ＣＶＤ工程では処理基板に対して紫外光領域の波長を有する光を照射すること
を特徴とする請求項２から５のいずれか１項に記載の酸化膜形成方法。 6. The oxide film forming method according to claim 2, wherein in the oxidation step and the CVD step, the processing substrate is irradiated with light having a wavelength in an ultraviolet region. 前記ＣＶＤ工程では前記光の照度を調整することで前記製膜速度を制御すること
を特徴とする請求項６に記載の酸化膜形成方法。 The method for forming an oxide film according to claim 6, wherein in the CVD step, the film forming speed is controlled by adjusting the illuminance of the light. 前記ＣＶＤ工程を経た処理基板をオゾン含有ガスの雰囲気または紫外光領域の波長を有する光が照射されたオゾン含有ガスの雰囲気に曝すアニール工程と、
このアニール工程を経た処理基板を前記ＣＶＤ工程に供する工程と
さらに有すること
を特徴とすることを特徴とする請求項１から７のいずれか１項に記載の酸化膜形成方法。 An annealing step in which the substrate subjected to the CVD step is exposed to an atmosphere of an ozone-containing gas or an atmosphere of an ozone-containing gas irradiated with light having a wavelength in the ultraviolet region;
8. The method for forming an oxide film according to claim 1, further comprising a step of subjecting the processed substrate that has undergone the annealing step to the CVD step. 前記アニール工程を経た処理基板を前記ＣＶＤ工程に供する工程を複数繰り返すことを特徴とする請求項８に記載の酸化膜形成方法。   The method for forming an oxide film according to claim 8, wherein the process of subjecting the processed substrate that has undergone the annealing process to the CVD process is repeated a plurality of times.
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JP2006080474A (en) * 2004-08-11 2006-03-23 Meidensha Corp Oxide film forming method and apparatus therefor
JP2008053562A (en) * 2006-08-25 2008-03-06 Meidensha Corp Method for forming gate insulating film, and method and device for manufacturing semiconductor device
JP2008053561A (en) * 2006-08-25 2008-03-06 Meidensha Corp Oxide film forming method and apparatus therefor
JP2008243926A (en) * 2007-03-26 2008-10-09 Meidensha Corp Method for reforming thin film

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0878694A (en) * 1994-08-31 1996-03-22 Semiconductor Energy Lab Co Ltd Manufacture of semiconductor device
JP2001338976A (en) * 2000-05-26 2001-12-07 Fujitsu Ltd Manufacturing method of semiconductor device
JP2004165625A (en) * 2002-11-14 2004-06-10 Sharp Corp Plasma method for manufacturing oxide thin film
JP2006080474A (en) * 2004-08-11 2006-03-23 Meidensha Corp Oxide film forming method and apparatus therefor
JP2008053562A (en) * 2006-08-25 2008-03-06 Meidensha Corp Method for forming gate insulating film, and method and device for manufacturing semiconductor device
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