JP3419439B2 - Method for cleaning semiconductor substrate - Google Patents
Method for cleaning semiconductor substrateInfo
- Publication number
- JP3419439B2 JP3419439B2 JP21714898A JP21714898A JP3419439B2 JP 3419439 B2 JP3419439 B2 JP 3419439B2 JP 21714898 A JP21714898 A JP 21714898A JP 21714898 A JP21714898 A JP 21714898A JP 3419439 B2 JP3419439 B2 JP 3419439B2
- Authority
- JP
- Japan
- Prior art keywords
- acid
- semiconductor substrate
- organic
- solution
- immersing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Description
【０００１】[0001]
【発明の属する技術分野】本発明はシリコンウェーハの
ような半導体基板の表面を洗浄する方法に関するもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning the surface of a semiconductor substrate such as a silicon wafer.
【０００２】[0002]
【従来の技術】この種の半導体基板の表面には、その製
造工程中に金属不純物や粒径が１μｍ以下の微粒子、有
機物等が付着し、かつ加工ダメージが形成される。半導
体デバイスの高集積化、高機能化に伴って、半導体基板
の表面がこれらの金属不純物や微粒子、有機物で汚染さ
れておらず、かつ加工ダメージがないことが益々要求さ
れ、そのための半導体基板の洗浄技術は半導体デバイス
技術全体の中で極めて重要なものとなってきている。2. Description of the Related Art On the surface of a semiconductor substrate of this type, metal impurities, fine particles having a particle size of 1 μm or less, organic substances, etc. adhere to the surface of the semiconductor substrate, and processing damage is formed. With higher integration and higher functionality of semiconductor devices, it is increasingly required that the surface of the semiconductor substrate is not contaminated with these metal impurities, fine particles, and organic substances, and there is no processing damage. Cleaning technology has become extremely important in the overall semiconductor device technology.
【０００３】従来の半導体基板の洗浄方法として、過酸
化水素と水酸化アンモニウムのＳＣ１溶液と、過酸化水
素と希塩酸のＳＣ２溶液を用いたＲＣＡ洗浄法が知られ
ている。このＲＣＡ洗浄法では、先ず半導体基板をＳＣ
１溶液に浸漬して、この溶液の酸化性及びアルカリ性の
性質により基板から微粒子及び有機物を除去する。即
ち、このＳＣ１溶液中では酸化と還元の両反応が同時に
行われ、アンモニアによる還元と過酸化水素による酸化
が同一槽で競合して起こり、同時に水酸化アンモニウム
溶液のエッチング作用によって微粒子及び有機物を基板
表面からリフトオフすることにより除去する。また半導
体基板の加工により生じた機械的な微小ダメージを除去
する。次いで半導体基板をフッ酸水溶液に浸漬して基板
表面の自然酸化膜を除去した後、この半導体基板をＳＣ
２溶液の酸性溶液に浸漬して、ＳＣ１溶液で不溶のアル
カリイオンや金属不純物を除去する。このため、ＲＣＡ
洗浄は水酸化アンモニウム溶液のエッチング作用により
清浄化された基板表面を酸性溶液の洗浄によって再清浄
化することになる。As a conventional method of cleaning a semiconductor substrate, an RCA cleaning method using an SC1 solution of hydrogen peroxide and ammonium hydroxide and an SC2 solution of hydrogen peroxide and dilute hydrochloric acid is known. In this RCA cleaning method, the semiconductor substrate is first SC
Immerse in one solution to remove particulates and organics from the substrate due to the oxidizing and alkaline nature of this solution. That is, in the SC1 solution, both oxidation and reduction reactions are performed at the same time, and ammonia reduction and hydrogen peroxide oxidation compete in the same tank. At the same time, the etching action of the ammonium hydroxide solution causes the fine particles and the organic substance to come into contact with the substrate. Remove by lifting off from the surface. Further, mechanical minute damage caused by processing the semiconductor substrate is removed. Then, the semiconductor substrate is immersed in an aqueous solution of hydrofluoric acid to remove the natural oxide film on the substrate surface, and then the semiconductor substrate is SC.
It is immersed in an acidic solution of 2 solutions to remove insoluble alkali ions and metal impurities with the SC1 solution. Therefore, RCA
The cleaning is to reclean the substrate surface cleaned by the etching action of the ammonium hydroxide solution by cleaning the acidic solution.
【０００４】[0004]
【発明が解決しようとする課題】ＲＣＡ洗浄における金
属不純物の除去効率を上げる方法として、水酸化アンモ
ニウム溶液中に金属を捕捉する錯化剤を添加する方法が
開示されている（特開平１０−１２５８４）。しかしこ
の方法では、錯化剤を添加した水酸化アンモニウム溶液
に過酸化水素水を加えると、過酸化水素水の酸化力によ
り錯化剤自身が分解してしまい、その効力が低下すると
いう問題がある。本発明の目的は、半導体基板の加工に
より生じた微小ダメージを除去し、また半導体基板表面
に付着する微粒子を少ない工程数で良好に除去する半導
体基板を洗浄する方法を提供することにある。本発明の
別の目的は、半導体基板表面に付着する金属不純物を良
好に除去する半導体基板を洗浄する方法を提供すること
にある。As a method for increasing the efficiency of removing metal impurities in RCA cleaning, a method of adding a complexing agent for trapping a metal in an ammonium hydroxide solution has been disclosed (JP-A-10-12584). ). However, in this method, when hydrogen peroxide solution is added to the ammonium hydroxide solution to which the complexing agent is added, the complexing agent itself is decomposed by the oxidizing power of the hydrogen peroxide solution, resulting in a problem that the efficacy is reduced. is there. An object of the present invention is to provide a method for cleaning a semiconductor substrate, which removes minute damage caused by processing of the semiconductor substrate and also favorably removes fine particles adhering to the surface of the semiconductor substrate with a small number of steps. Another object of the present invention is to provide a method of cleaning a semiconductor substrate, which is capable of satisfactorily removing metal impurities attached to the surface of the semiconductor substrate.
【０００５】[0005]
【課題を解決するための手段】請求項１に係る発明は、
図１に示すように半導体基板を過酸化水素と水酸化アン
モニウムを混合した混合液に浸漬する工程（ａ）と、こ
の混合液に浸漬した半導体基板を溶存オゾン水に浸漬す
る工程（ｂ）と、この溶存オゾン水に浸漬した半導体基
板を０．００５〜０．２５重量％のフッ酸を含む液に浸
漬する工程（ｃ）とを含む半導体基板を洗浄する方法で
ある。半導体基板表面に微粒子、有機物及び金属不純物
が付着し加工ダメージが形成されている場合に、半導体
基板を過酸化水素と水酸化アンモニウムを混合した混合
液に浸漬すると、酸化と還元の両反応が同時に行われ、
アンモニアによる還元と過酸化水素による酸化が同一槽
で競合して起こり、同時に水酸化アンモニウム溶液のエ
ッチング作用によって微粒子及び有機物が基板表面から
除去され、かつ半導体基板の加工により生じた微小ダメ
ージが除去される。続いて溶存オゾン水に基板を浸漬す
ることにより、基板の酸化が行われ、次のフッ酸による
還元処理を効果的に行うことができる。即ち、半導体基
板をフッ酸を含む液中に浸漬すると、基板の表面に形成
されていた自然酸化膜が除去され、自然酸化膜上の微粒
子及び金属不純物、並びに自然酸化膜中に含まれた金属
不純物がフッ酸を含む液中に移行するが、溶存オゾン水
で基板の酸化処理を十分に行っておくと、微粒子が基板
表面から離脱し易くなる。またフッ酸により自然酸化膜
の除去とともに、自然酸化膜中の金属不純物をも洗浄す
ることもできる。The invention according to claim 1 is
As shown in FIG. 1, a step (a) of immersing the semiconductor substrate in a mixed solution of hydrogen peroxide and ammonium hydroxide, and a step (b) of immersing the semiconductor substrate in this mixed solution in dissolved ozone water. And a step (c) of immersing the semiconductor substrate in the dissolved ozone water in a liquid containing 0.005 to 0.25% by weight of hydrofluoric acid. When fine particles, organic substances, and metal impurities are attached to the surface of the semiconductor substrate and processing damage is formed, if the semiconductor substrate is immersed in a mixed solution of hydrogen peroxide and ammonium hydroxide, both oxidation and reduction reactions occur simultaneously. Done,
Reduction by ammonia and oxidation by hydrogen peroxide compete in the same tank, and at the same time, the etching action of ammonium hydroxide solution removes fine particles and organic substances from the substrate surface, and also removes minute damage caused by processing of the semiconductor substrate. It Then, by immersing the substrate in the dissolved ozone water, the substrate is oxidized and the subsequent reduction treatment with hydrofluoric acid can be effectively performed. That is, when the semiconductor substrate is immersed in a liquid containing hydrofluoric acid, the natural oxide film formed on the surface of the substrate is removed, and the fine particles and metal impurities on the natural oxide film and the metal contained in the natural oxide film are removed. The impurities move into the liquid containing hydrofluoric acid, but if the substrate is sufficiently oxidized with the dissolved ozone water, the fine particles are easily separated from the substrate surface. In addition to removing the natural oxide film with hydrofluoric acid, metal impurities in the natural oxide film can be cleaned.
【０００６】請求項２に係る発明は、請求項１に係る発
明であって、工程（ｃ）の後で、半導体基板を酸化液に
浸漬する工程（ｄ）を更に含む方法である。半導体基板
を酸化液に浸漬すると、基板表面に酸化膜が形成され、
この酸化膜の形成により酸化液から取出した基板表面へ
の空気中の微粒子の付着が防止される。工程（ｃ）の液
が有機酸又は有機酸塩を含む場合には、金属不純物を錯
化しないで基板表面に付着していた有機酸又は有機物を
分解除去する。請求項３に係る発明は、請求項１又は２
に係る発明であって、工程（ｃ）の液がフッ酸に加えて
更に０．０００１重量％以上の有機酸又は有機酸塩を含
む方法である。フッ酸に加えて有機酸又は有機酸塩を含
む液に半導体基板を浸漬すると、この液は酸性溶液であ
るため、基板表面、金属不純物周面及び微粒子周面はそ
れぞれマイナスに荷電される。基板の表面電位と、金属
不純物及び微粒子の各表面電位が同一のため、金属不純
物及び微粒子は基板に対して反発する作用を生じ、基板
から液中に移行する。液中に移行した金属不純物は有機
酸の分子と錯体形成する。この金属錯塩の錯イオンも基
板の表面電位と同じマイナスである。この結果、液中に
移行した、それぞれマイナスに荷電された微粒子及び金
属錯体は、表面電位がマイナスである基板には再付着せ
ず、半導体基板表面に付着していた金属不純物及び微粒
子の双方が良好に除去される。The invention according to claim 2 is the invention according to claim 1, which further comprises a step (d) of immersing the semiconductor substrate in an oxidizing solution after the step (c). When a semiconductor substrate is immersed in an oxidizing solution, an oxide film is formed on the substrate surface,
The formation of this oxide film prevents the particles in the air from adhering to the surface of the substrate taken out from the oxidizing solution. When the liquid of the step (c) contains an organic acid or an organic acid salt, the organic acid or organic matter adhering to the substrate surface is decomposed and removed without complexing metal impurities. The invention according to claim 3 is the invention according to claim 1 or 2.
The method according to claim 1, wherein the liquid in step (c) further contains 0.0001% by weight or more of an organic acid or an organic acid salt in addition to hydrofluoric acid. When a semiconductor substrate is dipped in a liquid containing an organic acid or an organic acid salt in addition to hydrofluoric acid, this liquid is an acidic solution, so that the substrate surface, the metal impurity peripheral surface and the fine particle peripheral surface are each negatively charged. Since the surface potential of the substrate and the surface potentials of the metal impurities and the fine particles are the same, the metal impurities and the fine particles have a repulsive action with respect to the substrate and are transferred from the substrate into the liquid. The metal impurities transferred into the liquid form a complex with a molecule of the organic acid. The complex ion of this metal complex salt is also the same minus as the surface potential of the substrate. As a result, the negatively charged fine particles and the metal complex that have migrated into the liquid do not redeposit on the substrate having a negative surface potential, and both the metal impurities and the fine particles that have adhered to the semiconductor substrate surface are not removed. Good removal.
【０００７】請求項４に係る発明は、請求項３に係る発
明であって、工程（ｃ）の有機酸又は有機酸塩がシュウ
酸、クエン酸、コハク酸、エチレンジアミン四酢酸、酒
石酸、サリチル酸、ギ酸、酢酸、プロピオン酸、酪酸、
吉草酸、カプロン酸、カプリル酸、ラウリン酸、ミリス
チン酸、パルミチン酸、ステアリン酸、アラキン酸、安
息香酸、アクリル酸、アジピン酸、マロン酸、リンゴ
酸、グリコール酸、フタル酸、テレフタル酸、ピメリン
酸及びフマル酸からなる群より選ばれた１種又は２種以
上の有機酸又はその塩である方法である。上記列挙した
有機酸又は有機酸塩は基板を汚染する不純物の金属イオ
ンの錯化作用がある。請求項５に係る発明は、請求項２
ないし４いずれかに係る発明であって、工程（ｄ）の酸
化液が溶存オゾン水溶液、過酸化水素水又は硝酸である
洗浄方法である。上記列挙した酸化液は基板表面の酸化
膜の形成及び基板に付着した有機酸又は有機物の分解除
去作用がある。The invention according to claim 4 is the invention according to claim 3, wherein the organic acid or organic acid salt in step (c) is oxalic acid, citric acid, succinic acid, ethylenediaminetetraacetic acid, tartaric acid, salicylic acid, Formic acid, acetic acid, propionic acid, butyric acid,
Valeric acid, caproic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, benzoic acid, acrylic acid, adipic acid, malonic acid, malic acid, glycolic acid, phthalic acid, terephthalic acid, pimelic acid And one or more organic acids selected from the group consisting of fumaric acid and salts thereof. The above-listed organic acid or organic acid salt has a complexing effect on metal ions of impurities that contaminate the substrate. The invention according to claim 5 is claim 2
The invention according to any one of claims 1 to 4, wherein the oxidizing solution in step (d) is a dissolved ozone aqueous solution, hydrogen peroxide solution or nitric acid. The above-listed oxidizing solutions have the action of forming an oxide film on the surface of the substrate and decomposing and removing the organic acid or organic matter attached to the substrate.
【０００８】[0008]
【発明の実施の形態】本発明の好ましい実施の形態の洗
浄方法は、図１に示すように半導体基板を過酸化水素と
水酸化アンモニウムを混合した混合液に浸漬する工程
（ａ）と、この混合液に浸漬した半導体基板を溶存オゾ
ン水でリンスする工程（ｂ）と、この溶存オゾン水でリ
ンスした半導体基板を０．００５〜０．２５重量％のフ
ッ酸を含む液に浸漬する工程（ｃ）と、このフッ酸を含
む液に浸漬した半導体基板を酸化液に浸漬する工程
（ｄ）とを含む。上記工程（ａ）で用いられる混合液は
過酸化水素（Ｈ2Ｏ2）と水酸化アンモニウム（ＮＨ4Ｏ
Ｈ）との混合液であって、ＲＣＡ洗浄法で使用されるＳ
Ｃ１溶液に相当する溶液である。この混合液は前述した
ように、微粒子、有機物及び半導体基板の加工により生
じた微小ダメージの除去作用がある。上記工程（ｂ）で
用いられる溶存オゾン水溶液のオゾン濃度は０．５ｐｐ
ｍ以上であることが好ましい。０．５ｐｐｍ未満である
と基板の酸化が不十分であり、工程（ｃ）において微粒
子が基板表面から離脱しにくくなる。純水へのオゾンの
溶解限界は約２５ｐｐｍであるため、溶存オゾン水溶液
のオゾン濃度は２〜２５ｐｐｍがより好ましく、２〜１
０ｐｐｍが更に好ましい。BEST MODE FOR CARRYING OUT THE INVENTION A cleaning method according to a preferred embodiment of the present invention comprises a step (a) of immersing a semiconductor substrate in a mixed solution of hydrogen peroxide and ammonium hydroxide as shown in FIG. A step (b) of rinsing the semiconductor substrate immersed in the mixed solution with dissolved ozone water, and a step of immersing the semiconductor substrate rinsed with the dissolved ozone water in a solution containing 0.005 to 0.25% by weight of hydrofluoric acid ( c) and a step (d) of immersing the semiconductor substrate immersed in the solution containing hydrofluoric acid in an oxidizing solution. The mixed solution used in the step (a) is hydrogen peroxide (H 2 O 2 ) and ammonium hydroxide (NH 4 O).
S) used in the RCA cleaning method as a mixed solution with H).
It is a solution corresponding to the C1 solution. As described above, this mixed liquid has an action of removing minute damage caused by processing of the fine particles, the organic substance, and the semiconductor substrate. The ozone concentration of the dissolved ozone aqueous solution used in the above step (b) is 0.5 pp
It is preferably m or more. If it is less than 0.5 ppm, the oxidation of the substrate is insufficient, and it becomes difficult for the fine particles to separate from the substrate surface in the step (c). Since the dissolution limit of ozone in pure water is about 25 ppm, the ozone concentration of the dissolved ozone aqueous solution is more preferably 2 to 25 ppm,
0 ppm is more preferable.
【０００９】上記工程（ｃ）で用いられる液中のフッ酸
の濃度は０．００５〜０．２５重量％である。特に０．
００５〜０．１０重量％が好ましく、０．０５〜０．１
０重量％が更に好ましい。０．００５重量％未満では、
半導体基板表面の自然酸化膜の剥離作用に乏しく、また
０．２５重量％を越えると、この液が強酸となり微粒子
の表面電位がプラスになり、微粒子が基板表面に再付着
するようになる。また有機酸又は有機酸塩を加えた場合
に、液中の有機酸の解離が抑制され、その錯化作用が低
下する。The concentration of hydrofluoric acid in the liquid used in the above step (c) is 0.005 to 0.25% by weight. Especially 0.
005 to 0.10% by weight is preferable, and 0.05 to 0.1
0% by weight is more preferable. Below 0.005% by weight,
The natural oxide film on the surface of the semiconductor substrate is poor in peeling action, and when it exceeds 0.25% by weight, this solution becomes a strong acid, the surface potential of the fine particles becomes positive, and the fine particles reattach to the surface of the substrate. Further, when an organic acid or an organic acid salt is added, dissociation of the organic acid in the liquid is suppressed and its complexing action is reduced.
【００１０】この工程（ｃ）で用いられる液に加える有
機酸又は有機酸塩の種類及びその濃度は、除去しようと
する金属不純物の種類に応じて決められる。この工程の
液中の有機酸又は有機酸塩の濃度は０．０００１重量％
以上である。好ましくは０．００３〜１０重量％であ
る。０．０００１重量％未満では基板表面から遊離した
金属不純物イオンの錯化作用が十分でない不具合があ
る。上記有機酸又は有機酸塩としては、シュウ酸、クエ
ン酸、コハク酸、エチレンジアミン四酢酸（ＥＤＴ
Ａ）、酒石酸、サリチル酸、ギ酸、酢酸、プロピオン
酸、酪酸、吉草酸、カプロン酸、カプリル酸、ラウリン
酸、ミリスチン酸、パルミチン酸、ステアリン酸、アラ
キン酸、安息香酸、アクリル酸、アジピン酸、マロン
酸、リンゴ酸、グリコール酸、フタル酸、テレフタル
酸、ピメリン酸及びフマル酸等の有機酸又はその塩が挙
げられる。金属不純物を構成する金属元素に応じて、上
記有機酸又はその塩が適宜選定される。工程（ｄ）の酸
化液としては、溶存オゾン水溶液、過酸化水素水又は硝
酸が挙げられる。この中で溶存オゾン水溶液が高純度で
あるうえ、低濃度で酸化力に富み、入手しやすいため好
ましい。この溶存オゾン水溶液のオゾン濃度は０．５ｐ
ｐｍ以上であることが好ましい。０．５ｐｐｍ未満であ
ると基板表面に親水性の酸化膜を形成することが困難と
なり、また基板表面に付着していた有機酸や有機物の分
解除去作用が低下する。純水へのオゾンの溶解限界は約
２５ｐｐｍであるため、溶存オゾン水溶液のオゾン濃度
は２〜２５ｐｐｍがより好ましい。The type and concentration of the organic acid or organic acid salt added to the liquid used in step (c) are determined according to the type of metal impurities to be removed. The concentration of organic acid or acid salt in the liquid in this step is 0.0001% by weight.
That is all. It is preferably 0.003 to 10% by weight. If it is less than 0.0001% by weight, there is a problem that the complexing action of metal impurity ions released from the substrate surface is not sufficient. Examples of the organic acid or organic acid salt include oxalic acid, citric acid, succinic acid, ethylenediaminetetraacetic acid (EDT
A), tartaric acid, salicylic acid, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, benzoic acid, acrylic acid, adipic acid, malon Examples thereof include organic acids such as acids, malic acid, glycolic acid, phthalic acid, terephthalic acid, pimelic acid, and fumaric acid, or salts thereof. The organic acid or a salt thereof is appropriately selected according to the metal element constituting the metal impurities. Examples of the oxidizing solution in the step (d) include a dissolved ozone aqueous solution, hydrogen peroxide solution, and nitric acid. Of these, the dissolved ozone aqueous solution is preferred because it has high purity, is rich in oxidizing power at a low concentration, and is easily available. The ozone concentration of this dissolved ozone aqueous solution is 0.5 p
It is preferably at least pm. If it is less than 0.5 ppm, it becomes difficult to form a hydrophilic oxide film on the surface of the substrate, and the action of decomposing and removing the organic acids and organic substances attached to the surface of the substrate is reduced. Since the dissolution limit of ozone in pure water is about 25 ppm, the ozone concentration of the dissolved ozone aqueous solution is more preferably 2 to 25 ppm.
【００１１】[0011]
【実施例】次に本発明の実施例を比較例とともに説明す
る。
＜実施例１＞通常の研磨工程を経た未洗浄のシリコンウ
エーハを下記の条件にて洗浄処理した。工程（ａ）とし
て、上記シリコンウエーハをＳＣ１溶液（Ｈ2Ｏ：Ｈ2Ｏ
2(30%)：ＮＨ4ＯＨ(29%)＝５：１：０．５の混合液）に
浸漬し、８０℃で１０分間処理した。次いで工程（ｂ）
として、このシリコンウエーハをオゾン濃度が５ｐｐｍ
の室温の溶存オゾン水に１０分間浸漬した。次に工程
（ｃ）として、純水に対してフッ酸を０．０５重量％添
加した液に有機酸としてクエン酸を０．０６重％混合し
た液を用意し、この室温の液に上記溶存オゾン水に浸漬
していたシリコンウェーハを５分間浸漬した。次に工程
（ｄ）として、このシリコンウェーハをオゾン濃度が５
ｐｐｍの室温の溶存オゾン水溶液に１０分間浸漬した。EXAMPLES Next, examples of the present invention will be described together with comparative examples. <Example 1> An unwashed silicon wafer that has undergone a normal polishing process was washed under the following conditions. In the step (a), the silicon wafer was treated with SC1 solution (H 2 O: H 2 O).
2 (30%): NH 4 OH (29%) = 5: 1: 0.5 mixed solution) and treated at 80 ° C. for 10 minutes. Then step (b)
This silicon wafer has an ozone concentration of 5 ppm
It was immersed for 10 minutes in the dissolved ozone water at room temperature. Next, in the step (c), a liquid prepared by adding 0.05% by weight of hydrofluoric acid to pure water and 0.06% by weight of citric acid as an organic acid is prepared and dissolved in the liquid at room temperature. The silicon wafer that had been immersed in ozone water was immersed for 5 minutes. Next, as a step (d), the ozone concentration of the silicon wafer is adjusted to 5
It was immersed for 10 minutes in a dissolved ozone aqueous solution of ppm at room temperature.
【００１２】＜比較例１＞従来のＲＣＡ洗浄法を比較例
１の洗浄法として採用した。即ち、実施例１と同様に通
常の研磨工程を経た未洗浄のシリコンウエーハをＳＣ１
溶液（Ｈ2Ｏ：Ｈ2Ｏ2(30%)：ＮＨ4ＯＨ(29%)＝５：１：
０．５の混合液）に浸漬し、８０℃で１０分間処理した
後、このシリコンウエーハを超純水で１０分間リンスし
た。次にこのシリコンウエーハをＨ2Ｏ：ＨＦ(49%)＝５
０：１の混合液に１５秒間浸漬し、更に超純水でリンス
した。続いてリンスしたシリコンウェーハをＳＣ２溶液
（Ｈ2Ｏ：Ｈ2Ｏ2(30%)：ＨＣｌ(37%)＝６：１：１の混
合液）に浸漬し、８０℃に熱し、８０℃で１０分間処理
した。その後このシリコンウェーハを超純水で１０分間
リンスした。Comparative Example 1 A conventional RCA cleaning method was adopted as the cleaning method of Comparative Example 1. That is, as in Example 1, an uncleaned silicon wafer that had been subjected to a normal polishing process was replaced with SC1.
Solution (H 2 O: H 2 O 2 (30%): NH 4 OH (29%) = 5: 1:
After being immersed in a mixed solution of 0.5) and treated at 80 ° C. for 10 minutes, this silicon wafer was rinsed with ultrapure water for 10 minutes. Next, this silicon wafer is treated with H 2 O: HF (49%) = 5.
It was immersed in a 0: 1 mixed solution for 15 seconds and further rinsed with ultrapure water. Subsequently, the rinsed silicon wafer was immersed in an SC2 solution (mixed solution of H 2 O: H 2 O 2 (30%): HCl (37%) = 6: 1: 1), heated to 80 ° C., and heated at 80 ° C. It was treated for 10 minutes. Then, this silicon wafer was rinsed with ultrapure water for 10 minutes.
【００１３】＜比較試験と評価＞実施例１と比較例１の
それぞれ洗浄した後のシリコンウェーハ表面の残留した
粒径が０．１２μｍ以上の大きさの微粒子の数をパーテ
ィクルカウンタでカウントすることにより、ウェーハ上
の残留した微粒子の数を算出した。その結果を図２に示
す。図２から明らかなように、実施例１の方法で洗浄さ
れたウェーハに残留した微粒子の数は２９個と少なかっ
た。これに対して比較例１の方法で洗浄されたウェーハ
に残留した微粒子の数は４２０個と極めて多かった。こ
のことから、実施例１の洗浄方法は比較例１の洗浄方法
より微粒子を良く洗浄することが判明した。<Comparative Test and Evaluation> By counting the number of fine particles having a residual particle size of 0.12 μm or more on the surface of the silicon wafer after cleaning in Example 1 and Comparative Example 1, respectively, with a particle counter. The number of fine particles remaining on the wafer was calculated. The result is shown in FIG. As is clear from FIG. 2, the number of fine particles remaining on the wafer cleaned by the method of Example 1 was as small as 29 particles. On the other hand, the number of fine particles remaining on the wafer cleaned by the method of Comparative Example 1 was 420, which was extremely large. From this, it was found that the cleaning method of Example 1 was better in cleaning fine particles than the cleaning method of Comparative Example 1.
【００１４】[0014]
【発明の効果】以上述べたように、本発明の洗浄方法で
は、半導体基板を過酸化水素と水酸化アンモニウムの混
合液に浸漬し、更に溶存オゾン水に浸漬した後、フッ酸
を含む液に浸漬することにより、半導体基板から加工ダ
メージを除去し、また半導体基板表面に付着する微粒子
を良好に除去することができる。特にフッ酸を含む液に
有機酸又は有機酸塩を添加することにより、基板表面に
付着する金属不純物をも良好に除去することができる。As described above, according to the cleaning method of the present invention, the semiconductor substrate is dipped in a mixed solution of hydrogen peroxide and ammonium hydroxide, further dipped in dissolved ozone water, and then dipped in a solution containing hydrofluoric acid. By dipping, it is possible to remove the processing damage from the semiconductor substrate and to satisfactorily remove the fine particles adhering to the surface of the semiconductor substrate. In particular, by adding an organic acid or an organic acid salt to a liquid containing hydrofluoric acid, it is possible to satisfactorily remove metal impurities attached to the substrate surface.
【図１】本発明の実施の形態の洗浄工程を示す図。FIG. 1 is a diagram showing a cleaning process according to an embodiment of the present invention.
【図２】実施例１と比較例１の洗浄後のシリコンウェー
ハ表面に残留した微粒子の数を示す図。FIG. 2 is a diagram showing the number of fine particles remaining on the surface of a silicon wafer after cleaning in Example 1 and Comparative Example 1.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｃ１１Ｄ 7/60 Ｃ１１Ｄ 7/60 (56)参考文献 特開 平７−142438（ＪＰ，Ａ) 特開 平10−98018（ＪＰ，Ａ) 特開 平８−48996（ＪＰ，Ａ) 特開 平６−216098（ＪＰ，Ａ) 特開 平11−274129（ＪＰ，Ａ) 特開 平11−233476（ＪＰ，Ａ) 特開 平10−275795（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H01L 21/304 B08B 3/08 C11D 7/00 - 7/60 ─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. 7 identification code FI C11D 7/60 C11D 7/60 (56) References JP-A-7-142438 (JP, A) JP-A-10-98018 (JP , A) JP 8-48996 (JP, A) JP 6-216098 (JP, A) JP 11-274129 (JP, A) JP 11-233476 (JP, A) JP 10-275795 (JP, A) (58) Fields investigated (Int.Cl. 7 , DB name) H01L 21/304 B08B 3/08 C11D 7 /00-7/60
Claims (5)
ニウムを混合した混合液に浸漬する工程(a)と、この混
合液に浸漬した半導体基板を溶存オゾン水に浸漬する工
程(b)と、この溶存オゾン水に浸漬した半導体基板を
０．００５〜０．２５重量％のフッ酸を含む液に浸漬す
る工程(c)とを含む半導体基板を洗浄する方法。1. A step (a) of immersing a semiconductor substrate in a mixed solution of hydrogen peroxide and ammonium hydroxide; a step (b) of immersing the semiconductor substrate in this mixed solution in dissolved ozone water; And a step (c) of immersing the semiconductor substrate immersed in the dissolved ozone water in a liquid containing 0.005 to 0.25% by weight of hydrofluoric acid.
浸漬する工程(d)を更に含む請求項１記載の方法。2. The method according to claim 1, further comprising a step (d) of immersing the semiconductor substrate in an oxidizing solution after the step (c).
０００１重量％以上の有機酸又は有機酸塩を含む請求項
１又は２記載の方法。3. The liquid of step (c) is further added to hydrofluoric acid in an amount of 0.1.
The method according to claim 1 or 2, which comprises 0001% by weight or more of an organic acid or an organic acid salt.
酸、クエン酸、コハク酸、エチレンジアミン四酢酸、酒
石酸、サリチル酸、ギ酸、酢酸、プロピオン酸、酪酸、
吉草酸、カプロン酸、カプリル酸、ラウリン酸、ミリス
チン酸、パルミチン酸、ステアリン酸、アラキン酸、安
息香酸、アクリル酸、アジピン酸、マロン酸、リンゴ
酸、グリコール酸、フタル酸、テレフタル酸、ピメリン
酸及びフマル酸からなる群より選ばれた１種又は２種以
上の有機酸又はその塩である請求項３記載の方法。4. The organic acid or organic acid salt of step (c) is oxalic acid, citric acid, succinic acid, ethylenediaminetetraacetic acid, tartaric acid, salicylic acid, formic acid, acetic acid, propionic acid, butyric acid,
Valeric acid, caproic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, benzoic acid, acrylic acid, adipic acid, malonic acid, malic acid, glycolic acid, phthalic acid, terephthalic acid, pimelic acid The method according to claim 3, which is one or more organic acids selected from the group consisting of and fumaric acid or salts thereof.
過酸化水素水又は硝酸である請求項２ないし４いずれか
記載の方法。5. The oxidizing solution in step (d) is a dissolved ozone aqueous solution,
The method according to any one of claims 2 to 4, which is hydrogen peroxide water or nitric acid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21714898A JP3419439B2 (en) | 1998-07-31 | 1998-07-31 | Method for cleaning semiconductor substrate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21714898A JP3419439B2 (en) | 1998-07-31 | 1998-07-31 | Method for cleaning semiconductor substrate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000049133A JP2000049133A (en) | 2000-02-18 |
| JP3419439B2 true JP3419439B2 (en) | 2003-06-23 |
Family
ID=16699619
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21714898A Expired - Lifetime JP3419439B2 (en) | 1998-07-31 | 1998-07-31 | Method for cleaning semiconductor substrate |
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| Country | Link |
|---|---|
| JP (1) | JP3419439B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002094462A1 (en) * | 2001-05-22 | 2002-11-28 | Mitsubishi Chemical Corporation | Method for cleaning surface of substrate |
| JP4162211B2 (en) * | 2002-09-05 | 2008-10-08 | コバレントマテリアル株式会社 | Method for cleaning silicon wafer and cleaned silicon wafer |
| JP4831216B2 (en) | 2009-07-28 | 2011-12-07 | 株式会社Ｓｕｍｃｏ | Wafer surface treatment method |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3174823B2 (en) * | 1992-12-01 | 2001-06-11 | 株式会社ピュアレックス | Silicon wafer cleaning method |
| JPH07142438A (en) * | 1993-11-22 | 1995-06-02 | Tadahiro Omi | Cleaning equipment, production system and line for semiconductor |
| US5853491A (en) * | 1994-06-27 | 1998-12-29 | Siemens Aktiengesellschaft | Method for reducing metal contamination of silicon wafers during semiconductor manufacturing |
| JP3046208B2 (en) * | 1994-08-05 | 2000-05-29 | 新日本製鐵株式会社 | Cleaning liquid for silicon wafer and silicon oxide |
| JP3649534B2 (en) * | 1996-09-19 | 2005-05-18 | シルトロニック・ジャパン株式会社 | Silicon wafer and silicon oxide cleaning solution |
| JPH11233476A (en) * | 1997-12-01 | 1999-08-27 | Mitsubishi Electric Corp | Treatment of semiconductor substrate |
| JPH11274129A (en) * | 1998-03-25 | 1999-10-08 | Mitsubishi Materials Silicon Corp | Cleaning of semiconductor substrate |
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1998
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| Publication number | Publication date |
|---|---|
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