JP4023907B2

JP4023907B2 - Substrate processing method

Info

Publication number: JP4023907B2
Application number: JP13614398A
Authority: JP
Inventors: 浩司阿藤
Original assignee: Ebara Corp
Current assignee: Ebara Corp
Priority date: 1998-04-30
Filing date: 1998-04-30
Publication date: 2007-12-19
Anticipated expiration: 2018-04-30
Also published as: JPH11317389A

Description

【０００１】
【発明の属する技術分野】
本発明は、半導体基板、ガラス基板、液晶パネル等の高度の清浄度が要求される基板を乾燥する基板処理方法に関する。
【０００２】
【従来の技術】
近年、半導体デバイスの高集積化が進むにつれて半導体基板上の回路の配線が微細化し、配線間距離もより狭くなりつつある。従って、半導体基板上に配線間距離よりも大きな微粒子が存在すると、配線がショートするなどの不具合が生じるため、基板上に残るパーティクルの寸法や量に対する許容限度はますます厳しいものとなっている。このような事情はマスク等に用いるガラス基板、或いは液晶パネル等の基板のプロセス処理においても同様である。
【０００３】
例えば、基板のエッチングやイオン注入に伴うレジスト剥離、さらには基板のポリッシング（研磨）後に、基板に付着するパーティクルや有機物等を薬液で洗浄し、除去した後に純水で濯ぎ、乾燥する工程を行なう。この乾燥工程は処理の最終工程であるので、雰囲気中の清浄度も高くすることが望ましい。
【０００４】
従来、この種の乾燥装置としては、例えば１０００〜５０００ｒｐｍで基板を高速回転させ、この時の遠心力で基板表面に付着している液体を放射状に吹き飛ばすようにした、いわゆるスピン乾燥装置が一般に知られている。また、チャンバー内で基板（ウエハ）を水平回転させながら上部の吸気孔から気体を吹き付け、下部の排気孔から排気することによって、基板表面に均一な層流を形成する方法が知られている。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記スピン乾燥装置にあっては、基板を該基板の周縁部で保持する爪等の把持部と、この把持部を固定する風車状或いは円盤状のホィールが必要で、しかもこのホィールが基板と一体となって高速回転するようになっているため、この時の遠心力に耐える強度が要求される。しかも、スピン乾燥装置を洗浄装置と一体化しようとすると、ホィールが邪魔となって、ホィールと向き合う基板の裏面のスクラブ洗浄や流体による洗浄が極めて困難となるばかりでなく、把持部で把持された基板の周縁部の洗浄も極めて困難となってしまう。
【０００６】
また、基板を水平方向に回転すると、基板の裏面近傍の流体がその粘性により基板の回転運動に引きずられて回転し、遠心力によって半径方向外向きの速度成分を持つ気流が生じる。このため、チャンバー内に全体として上から下へ向かう清浄な気体の流れが形成されていても、基板裏面側に、軸に沿って上昇し、径方向外側に向かい、基板縁部で下降する局所的な循環流が形成される。このような循環流は、基板を回転させる回転機構の軸受等から発生する汚染物質を巻き上げるので基板裏面を汚染する可能性がある。
【０００７】
なお、基板の周縁部を挟持して該基板を保持する回転自在な複数のコロを有する回転機構を備え、この回転機構で基板を回転させつつ、ブラシ又はスポンジ等の洗浄具を基板に当接させてスクラブ洗浄を行うようにした洗浄装置も知られているが、この種の洗浄装置にあっては、基板とコロとの間で滑りが発生して基板を高速回転させることができず、乾燥装置としての機能を付加することは一般に困難である。
【０００８】
本発明は上述した事情に鑑み、基板の周囲に気流の乱れを発生することがなく、基板両面を高い清浄度で乾燥させることができ、しかも、基板両面をその全面に亘って洗浄できることが可能な基板処理方法を提供することを目的とする。
【０００９】
【課題を解決するための手段】
上記課題を解決するため本発明では、基板の周縁部を複数のコロで挟持し該コロを回転させて基板を回転させながら、基板の表面及び裏面に一対の洗浄具をそれぞれ摺接させつつ回転させて基板の表面及び裏面をスクラブ洗浄し、前記スクラブ洗浄終了後、前記洗浄具を待避位置に待避させ、基板の表面及び裏面に、待避位置にあった整流板をそれぞれ近接させて、基板の表面と整流板との間、及び基板の裏面と整流板の間に不活性ガス流路をそれぞれ形成し、基板を回転させながら、前記各整流板の中央にそれぞれ設けた噴射ノズルから前記各不活性ガス流路に不活性ガスをそれぞれ導入して、基板の表面及び裏面を乾燥させ、しかる後、前記整流板を待避位置に戻すことを特徴とする。これにより、複数のコロで基板を回転させながら、この表裏両面からＮ_２，Ａｒ等の不活性ガスを噴射することで、逆汚染を与えるような気流の乱れの発生を防止して、基板を高い清浄度で乾燥させ、しかも、乾燥時以外の時には整流板を退避させることができる。
【００１０】
また、基板の表面及び裏面に沿って流れる不活性ガスの流れ方向と量を整流板を介してより均一にすることができる。
【００１１】
さらに、整流板を退避させた状態で、基板を回転させつつ、洗浄具を基板の両面に当接させることで、基板両面の全面に亘る洗浄を行うことができる。
【００１２】
【発明の実施の形態】
以下、本発明の実施の形態を図面に基づいて説明する。図１は本発明の基板処理方法を行う基板処理装置を模式的に示す分解斜視図である。
図１に示すように、この基板処理装置には、基板（半導体ウエハ）Ｗの周縁部を挟持して該基板Ｗを水平に保持する複数（図示では計６個）のコロ１を有する回転機構２が備えられている。前記コロ１は、サーボモータ３に直結され、このサーボモータ３の駆動に伴って回転するよう構成されているとともに、サーボモータ３の回転速度及び回転角度を検知してその回転を制御する制御装置４が備えられている。尚、図示しないが、基板処理装置には、基板をロボットハンド等の移送手段によりコロ１に挟持、搬出するために、コロ１を略水平方向に開閉するための手段を設けている。
【００１３】
前記回転機構２は、基板Ｗを保持して、これを５０〜３００ｒｐｍ程度の低速で回転させるものであり、このように、回転するコロ１で基板Ｗを低速回転させることで、それ程の強度が要求されない。
なお、この例では、全てのコロ１をサーボモータ３で個々に駆動するようにしているが、１個のコロのみをサーボモータで回転させ、他のコロを回転自在に支承するようにしても良い。
【００１４】
一方、前記コロ１で水平に保持された基板Ｗの表面及び裏面に近接して、この表面及び裏面との間に図２に示すように上部不活性ガス流路１０ａ及び下部不活性ガス流路１０ｂをそれぞれ形成する略円板状の上部整流板１１ａ及び下部整流板１１ｂが該基板Ｗを略水平に挟んで上下に配置されている。前記上部整流板１１ａ及び下部整流板１１ｂは上部シリンダ１２ａ及び下部シリンダ１２ｂにそれぞれ接続されており、これら上下部整流板１１ａ，１１ｂは上下部シリンダ１２ａ，１２ｂによって、前記基板Ｗの表面及び裏面に近接する図２に示す乾燥位置と、この位置から退避した図１に示す退避位置との間をそれぞれ移動するように構成されている。上部及び下部整流板の材質としては、高強度樹脂あるいは金属に樹脂コーティングを施した素材等を使用している。
【００１５】
このように、基板Ｗの表面及び裏面に上部整流板１１ａ及び下部整流板１１ｂを最適な距離に近接させて上部不活性ガス流路１０ａ及び下部不活性ガス流路１０ｂをそれぞれ形成することにより、基板Ｗの表面及び裏面に沿って流すＮ₂，Ａｒ等の不活性ガスの流れ方向と量をより均一にすることができる。
【００１６】
さらに、前記上部整流板１１ａ及び下部整流板１１ｂの中央には、不活性ガス噴射手段としての噴射ノズル１３ａ，１３ｂが設けられ、この噴射ノズル１３ａ，１３ｂは、例えば不活性ガス供給源から延びる可撓性を有する不活性ガス供給パイプ１４にそれぞれ接続されている。
【００１７】
また、前記回転機構２の側方に位置して、前記コロ１で保持された基板Ｗの表面及び裏面に接離自在な一対の洗浄具ロール２０ａ，２０ｂが配置され、このロール２０ａ，２０ｂは、図１に実線で示す退避位置と、仮想線（破線）で示す洗浄位置との間をそれぞれ移動するように構成されている。ロール２０ａ，２０ｂは、それぞれモータ２１ａ，２１ｂに直結されて、モータ２１ａ，２１ｂの回転に伴って回転するようになっている。ロール２０ａ，２０ｂの周囲には最表面に複数の凹凸を有し、多孔質のＰＶＡ（ポリビニルアルコール）製のスポンジ材の円筒スポンジが固着されている。またブラシ材をロール２０ａ，２０ｂの周囲に設けてもよい。
【００１８】
ここに、前記整流板１１ａ，１１ｂの退避位置は、前記ロール２０ａ，２０ｂの洗浄位置と退避位置との間の移動や、基板Ｗのコロ１への受渡しに干渉しないように設定されている。尚、図示しないがロール２０ａ，２０ｂが洗浄位置にあるとき、基板Ｗの表裏面共に洗浄液を供給する手段が設けられている。
【００１９】
次に、上記のように構成した基板処理装置の作用について説明する。
先ず、整流板１１ａ，１１ｂ及びロール２０ａ，２０ｂが退避位置にある状態で、エッチングやイオン注入、又はポリッシング（研磨）等の処理工程が終わった基板１を搬入し、その周縁部をコロ１で保持する。この状態で、サーボモータ３に作動命令が入力され、コロ１を回転させることで、基板Ｗを、例えば５０〜３００ｒｐｍ程度の低速で回転させ、同時に洗浄液を基板Ｗの表裏面に供給した状態で、退避位置にあったロール２０ａ，２０ｂを洗浄位置に移動させ、これを基板Ｗの表面及び裏面に摺接させつつ回転させることで、基板Ｗの両面のスクラブ洗浄を行う。この時、基板Ｗは、回転する複数のコロ１でその周縁部を保持されて回転しているため、このコロ１の干渉を回避して、その全面に亘る洗浄が可能となる。
【００２０】
この洗浄終了後、基板Ｗを回転させた状態でロール２０ａ，２０ｂを退避位置まで退避させ、しかる後、退避位置にあった整流板１１ａ，１１ｂを乾燥位置まで移動させる。そして、不活性ガス供給パイプ１４から不活性ガスを導入して噴射ノズル１３ａ，１３ｂから噴射させる。すると、基板Ｗは、回転による遠心力と、不活性ガスが不活性ガス流路１０ａ，１０ｂに沿って流れることによるガス圧（流速）を受け、これが相乗効果となって徐々に乾燥させられる。この時、基板Ｗは、表裏両面で不活性ガスで囲まれるため、自然酸化膜の生成が防止され、しかも、雰囲気中に浮遊しているパーティクル等の汚染物質の影響を受けることがない。
【００２１】
なお、温度等を調節した不活性ガスを用いることで、乾燥時間を短縮することができる。また、図示しないが、噴射ノズル１３ａ，１３ｂから噴射される不活性ガスの流量、温度等に合わせた最適な位置に整流板１１ａ，１１ｂを移動させる調節機構を設けることが望ましい。
【００２２】
そして、この乾燥作業終了後、整流板１１ａ，１１ｂを退避位置まで退避させ、乾燥後の基板Ｗをコロ１から取り出して、次工程に搬送するのであり、これにより、基板の洗浄と乾燥を連続して行うことができる。
【００２４】
【発明の効果】
以上説明したように、本発明によれば、基板の周囲に気流の乱れを発生することがなく、基板両面を高い清浄度で乾燥させることができる。しかも、基板両面をその全面に亘って洗浄でき、基板の洗浄と乾燥を連続して行うことができる。
【図面の簡単な説明】
【図１】本発明に係る基板処理方法を行う基板処理装置の一実施形態を模式的に示す分解斜視図である。
【図２】本発明に係る基板処理方法を行う基板処理装置における整流板が乾燥位置にある時の縦断図である。
【符号の説明】
１コロ
２回転機構
１０ａ，１０ｂ不活性ガス流路
１１ａ，１１ｂ整流板
１３ａ，１３ｂ噴射ノズル（不活性ガス噴射手段）
２０ａ，２０ｂ洗浄具ロール[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate processing method for drying a substrate that requires a high degree of cleanness, such as a semiconductor substrate, a glass substrate, and a liquid crystal panel.
[0002]
[Prior art]
In recent years, with the progress of high integration of semiconductor devices, circuit wiring on a semiconductor substrate is miniaturized and the distance between wirings is becoming narrower. Therefore, if fine particles larger than the distance between the wirings are present on the semiconductor substrate, problems such as short-circuiting of the wiring occur, so that the allowable limit on the size and amount of particles remaining on the substrate is becoming stricter. Such a situation also applies to the processing of a glass substrate used for a mask or the like or a substrate such as a liquid crystal panel.
[0003]
For example, after the substrate is etched or resist is removed along with ion implantation, and the substrate is polished (polished), particles and organic substances adhering to the substrate are washed with a chemical solution, removed, rinsed with pure water, and dried. . Since this drying process is the final process, it is desirable to increase the cleanliness in the atmosphere.
[0004]
Conventionally, as this type of drying apparatus, for example, a so-called spin drying apparatus in which a substrate is rotated at a high speed of 1000 to 5000 rpm, for example, and the liquid adhering to the substrate surface is blown radially by the centrifugal force at this time is generally known. It has been. Further, a method is known in which a uniform laminar flow is formed on the substrate surface by blowing gas from an upper intake hole and exhausting air from a lower exhaust hole while horizontally rotating the substrate (wafer) in a chamber.
[0005]
[Problems to be solved by the invention]
However, in the above spin drying apparatus, a gripping part such as a claw for holding the substrate at the peripheral edge of the substrate and a windmill-like or disc-like wheel for fixing the gripping part are necessary, and this wheel is a substrate. Therefore, the strength required to withstand the centrifugal force at this time is required. Moreover, when trying to integrate the spin drying device with the cleaning device, the wheel becomes an obstacle, and scrub cleaning of the back surface of the substrate facing the wheel and cleaning with a fluid become extremely difficult, as well as being gripped by the gripping portion. Cleaning the peripheral edge of the substrate is extremely difficult.
[0006]
Further, when the substrate is rotated in the horizontal direction, the fluid in the vicinity of the back surface of the substrate is rotated by the rotational movement of the substrate due to its viscosity, and an air flow having a radially outward velocity component is generated by the centrifugal force. For this reason, even if a clean gas flow from the top to the bottom is formed in the chamber as a whole, the gas rises along the axis on the back side of the substrate, moves radially outward and descends at the edge of the substrate. A general circulation flow is formed. Such a circulating flow winds up contaminants generated from a bearing of a rotating mechanism that rotates the substrate, and may contaminate the back surface of the substrate.
[0007]
In addition, a rotating mechanism having a plurality of rotatable rollers for holding the substrate by holding the peripheral edge of the substrate is provided, and a cleaning tool such as a brush or a sponge is brought into contact with the substrate while rotating the substrate by the rotating mechanism. There is also known a cleaning device that performs scrub cleaning, but in this type of cleaning device, slippage occurs between the substrate and the roller, and the substrate cannot be rotated at a high speed. It is generally difficult to add a function as a drying device.
[0008]
The present invention has been made in view of the above circumstances, it is not possible to generate the turbulence around the substrate, it is possible to dry the board both sides with a high degree of cleanliness, yet, Ru can be cleaned over the both surfaces of the substrate to the entire surface and to provide a this and capable substrate processing method.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, while rotating the substrate by holding the peripheral portion of the substrate with a plurality of rollers and rotating the rollers, the pair of cleaning tools are rotated in contact with the front and back surfaces of the substrate, respectively. The scrub cleaning is performed on the front and back surfaces of the substrate.After the scrub cleaning, the cleaning tool is retracted to the retracted position, and the current plate located at the retracted position is brought close to the front and back surfaces of the substrate, respectively. An inert gas flow path is formed between the front surface and the current plate, and between the rear surface of the substrate and the current plate, and the inert gas is supplied from the injection nozzle provided at the center of each current plate while rotating the substrate. An inert gas is introduced into each flow path to dry the front and back surfaces of the substrate, and then the rectifying plate is returned to the retracted position . Thus, while rotating the substrate at a plurality of co-B, by injecting the inert gas N _2, Ar or the like from the both sides, to prevent the occurrence of air flow, such as to provide a back contamination turbulence, the substrate Can be dried with a high degree of cleanliness, and the current plate can be retracted at times other than during drying.
[0010]
In addition, it is a more uniformly to Turkey the surface and the flow direction and amount of the inert gas flows along the back surface of the base plate through the rectifying plate.
[0011]
Further, in a state of being retracted rectifying plate, while the substrate is rotating, the cleaning tool that is brought into contact with both surfaces of the substrate can be washed over the entire surface of the substrate duplex.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view schematically showing a substrate processing apparatus for performing the substrate processing method of the present invention.
As shown in FIG. 1, rotating the substrate processing apparatus of this, with a roller of the plurality (total of six in the illustrated) for holding a substrate (semiconductor wafer) W and the peripheral portion by holding the substrate W horizontally in A mechanism 2 is provided. The roller 1 is directly connected to the servo motor 3 and is configured to rotate as the servo motor 3 is driven. The control device detects the rotation speed and rotation angle of the servo motor 3 and controls the rotation of the roller 1. 4 is provided. Although not shown, the board processor, clamping the substrate to the roller 1 by the transfer means such as a robot hand, in order to carry-out is provided with a means for opening and closing the roller 1 substantially in the horizontal direction.
[0013]
The rotating mechanism 2 holds the substrate W and rotates the substrate W at a low speed of about 50 to 300 rpm. Thus, by rotating the substrate W at a low speed with the rotating roller 1, the strength is so high. Not required.
In this example, all the rollers 1 are individually driven by the servo motor 3, but only one roller is rotated by the servo motor and the other rollers are supported rotatably. good.
[0014]
On the other hand, close to the front and back surfaces of the substrate W held horizontally by the roller 1, the upper inert gas flow channel 10a and the lower inert gas flow channel are provided between the front and back surfaces as shown in FIG. A substantially disc-shaped upper rectifying plate 11a and a lower rectifying plate 11b, which respectively form 10b, are arranged above and below with the substrate W sandwiched substantially horizontally. The upper rectifying plate 11a and the lower rectifying plate 11b are connected to an upper cylinder 12a and a lower cylinder 12b, respectively. These upper and lower rectifying plates 11a and 11b are attached to the front and back surfaces of the substrate W by the upper and lower cylinders 12a and 12b. It is comprised so that it may each move between the dry position shown in FIG. 2 which adjoins, and the retracted position shown in FIG. 1 evacuated from this position. As the material of the upper and lower rectifying plates, a high-strength resin or a material obtained by applying a resin coating to a metal is used.
[0015]
In this way, by forming the upper inert gas channel 10a and the lower inert gas channel 10b on the front and back surfaces of the substrate W by bringing the upper current plate 11a and the lower current plate 11b close to the optimum distance, respectively, The flow direction and amount of inert gas such as N ₂ and Ar flowing along the front and back surfaces of the substrate W can be made more uniform.
[0016]
Further, injection nozzles 13a and 13b as inert gas injection means are provided in the center of the upper rectifying plate 11a and the lower rectifying plate 11b, and the injection nozzles 13a and 13b can extend from, for example, an inert gas supply source. Each is connected to an inert gas supply pipe 14 having flexibility.
[0017]
In addition, a pair of cleaning tool rolls 20a and 20b which are located on the side of the rotation mechanism 2 and can be brought into contact with and separated from the front and back surfaces of the substrate W held by the roller 1 are disposed. 1 is configured to move between a retracted position indicated by a solid line in FIG. 1 and a cleaning position indicated by a virtual line (broken line). The rolls 20a and 20b are directly connected to the motors 21a and 21b, respectively, and are rotated with the rotation of the motors 21a and 21b. Around the rolls 20a and 20b, a cylindrical sponge made of porous PVA (polyvinyl alcohol) sponge material having a plurality of irregularities on the outermost surface is fixed. Further, a brush material may be provided around the rolls 20a and 20b.
[0018]
Here, the retreat positions of the current plates 11a and 11b are set so as not to interfere with the movement of the rolls 20a and 20b between the cleaning position and the retreat position and the delivery of the substrate W to the roller 1. Although not shown, there is provided means for supplying a cleaning liquid to both the front and back surfaces of the substrate W when the rolls 20a and 20b are in the cleaning position.
[0019]
Next, the operation of the substrate processing apparatus configured as described above will be described.
First, in a state where the current plates 11a and 11b and the rolls 20a and 20b are in the retracted position, the substrate 1 that has been subjected to the processing steps such as etching, ion implantation, or polishing (polishing) is carried in, and the peripheral portion thereof is rolled by the roller 1 Hold. In this state, an operation command is input to the servo motor 3 and the roller 1 is rotated, whereby the substrate W is rotated at a low speed of, for example, about 50 to 300 rpm, and at the same time the cleaning liquid is supplied to the front and back surfaces of the substrate W. The scrub cleaning of both surfaces of the substrate W is performed by moving the rolls 20a and 20b that have been in the retracted position to the cleaning position and rotating them while being in sliding contact with the front and back surfaces of the substrate W. At this time, since the peripheral portion of the substrate W is rotated by a plurality of rotating rollers 1 rotating, the entire surface of the substrate W can be avoided while avoiding the interference of the rollers 1.
[0020]
After this cleaning is completed, the rolls 20a and 20b are retracted to the retracted position while the substrate W is rotated, and then the rectifying plates 11a and 11b in the retracted position are moved to the drying position. Then, an inert gas is introduced from the inert gas supply pipe 14 and injected from the injection nozzles 13a and 13b. Then, the substrate W receives the centrifugal force due to the rotation and the gas pressure (flow velocity) due to the inert gas flowing along the inert gas flow paths 10a and 10b, and this is gradually dried by a synergistic effect. At this time, since the substrate W is surrounded by an inert gas on both the front and back surfaces, generation of a natural oxide film is prevented, and the substrate W is not affected by contaminants such as particles floating in the atmosphere.
[0021]
In addition, drying time can be shortened by using the inert gas which adjusted temperature etc. Although not shown, the injection nozzle 13a, the flow rate of the inert gas injected from 13b, the rectifying plate 11a to combined optimum position of the temperature or the like, it is not to want to provide an adjustment mechanism for moving the 11b.
[0022]
Then, after this drying operation is completed, the current plates 11a and 11b are retracted to the retracted position, and the dried substrate W is taken out of the roller 1 and transported to the next process, whereby the substrate cleaning and drying are continuously performed. It can be done in succession.
[0024]
【The invention's effect】
As described above, according to the present invention, without generating a turbulence around the substrate, it is possible to dry the board both sides with high cleanliness. Moreover, can be cleaned over the both surfaces of the substrate to the entire surface, it is a TURMERIC rows to continue communicating dried and washed in board.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view schematically showing an embodiment of a substrate processing apparatus for performing a substrate processing method according to the present invention.
FIG. 2 is a longitudinal sectional view when a current plate is in a dry position in a substrate processing apparatus for performing a substrate processing method according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Roller 2 Rotating mechanism 10a, 10b Inert gas flow path 11a, 11b Rectification plate 13a, 13b Injection nozzle (inert gas injection means)
20a, 20b Cleaning tool roll

Claims

Scrub cleaning of the front and back surfaces of the substrate by holding the peripheral edge of the substrate with a plurality of rollers and rotating the rollers to rotate the substrate while rotating a pair of cleaning tools in sliding contact with the front and back surfaces of the substrate. And
After the scrub cleaning, the cleaning tool is retracted to a retracted position,
The inert gas flow path is formed between the front surface and the current plate of the substrate, and between the front surface and the current plate of the substrate, and between the rear surface of the substrate and the current plate, respectively, by bringing the current plate in the retreat position close to the front surface and the rear surface of the substrate.
While rotating the substrate, an inert gas is introduced into each of the inert gas flow paths from the spray nozzle provided in the center of each of the rectifying plates, and the front and back surfaces of the substrate are dried.
A substrate processing method comprising returning the current plate to a retracted position.