JPS6072233A - Washing device for semiconductor wafer - Google Patents

Abstract

PURPOSE:To effectively remove organic contaminant deposited on the surface of a wafer by a method wherein the title device is composed of a washing bath in which a washing chemical solution is contained, a hold carrier for semiconductor wafers dipped therein, an ultrasonic wave generator that gives oscillation, an irradiator with ultraviolet rays to wafers, etc. CONSTITUTION:The wafer carrier 2 holding the semiconductor wafers 1 to be washed is contained in the wafer washing bath 3 made of transparent quartz surrounded by a casing 13, and many ultraviolet ray lamps 9 are arranged in the gap between the carrier 2 and the bath 3. Chemical solution supply ports 4-7 are made opposed to the upper surface of the bath 3, and the ultrasonic wave generator 10 surrounding a valve 11 and a duct is installed outside the bottom. The device being thus constructed, hydrofluoric acid, hydrogen peroxide, hydrochloric acid, aqueous ammonia, persulfuric acid, etc. are poured from the supply ports 4-7, respectively; at the same time the bath 3 is filled with the chemical solution 8 obtained by feed of pure water from the duct 12. Thereafter, the lamps 9 and the generator 10 are set in motion at the same time, and the deposited organic substance is thus removed.

Description

【発明の詳細な説明】 〔発明の技術分野〕 本発明は半導体ウェーハ（単結晶から切り出したものか
ら、酸化、拡散等のウェーハエ程を経たものまでを含む
）の表面汚染物を除去する半導体ウェーハの洗浄装置に
関する。[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a semiconductor wafer for removing surface contaminants from semiconductor wafers (including those cut from a single crystal to those that have undergone wafer processing such as oxidation and diffusion). The present invention relates to a cleaning device.

〔発明の技術的背景〕[Technical background of the invention]

近年、半導体デバイスの高性能化、高密度化に伴い、ま
すます高精度の微細加工技術が要求されている。ところ
で、ウェーハ処理工程で混入、残存する微粒子状耐着物
、被膜状附着物等の表面汚染物は、プロセス加工精度の
低減、デバイス特性の信頼性低下等を招（ため、それら
表面汚染物除去はデバイスの歩留り向上のために不可欠
になっている。In recent years, as the performance and density of semiconductor devices have increased, more and more highly accurate microfabrication technology has been required. By the way, surface contaminants such as particulate deposits and film-like deposits that are mixed in and remain during the wafer processing process can reduce process precision and reliability of device characteristics (therefore, it is necessary to remove these surface contaminants). It has become essential for improving device yield.

従来のウェーハ洗浄工程は、下記■〜■の素工程の単な
る組合せにより成っている。すなわち、■有機溶剤処理
による表面有機物汚染除去、■酸化性酸、アルカリ処理
による表面有機物汚染除去、■稀フッ酸処理による自然
酸化膜除去、■酸化性酸処理による表面残存重金属除去
、■界面活性剤、アルカリまたは機械的作用等の併用に
よる微粒子除去、■純水洗浄等である。そして、半導体
ウェーハの洗浄装置もこれらの目的に即したものが実用
化されている。The conventional wafer cleaning process consists of a simple combination of the elementary steps (1) to (4) below. Namely, ■ Removal of surface organic contamination by organic solvent treatment, ■ Removal of surface organic contamination by oxidizing acid and alkali treatment, ■ Removal of natural oxide film by dilute hydrofluoric acid treatment, ■ Removal of residual heavy metals on the surface by oxidizing acid treatment, and ■ Surface activity. These include removal of fine particles by combined use of chemical agents, alkali, or mechanical action, ■cleaning with pure water, etc. Semiconductor wafer cleaning apparatuses that meet these objectives have also been put into practical use.

〔背景技術の問題点〕[Problems with background technology]

しかし、上記の如き従来技術では、有機性表面汚染物を
十分に行なうことはできない。すなわち、有機溶剤中に
ウェーハを浸漬するという物理的洗浄脱離、溶解のみで
は、強固な表面耐着物を完全には除去できない。また、
有機物除去処理に使用さｎる有機溶剤自体、あるいはそ
れに続いてなされる一連の素工径での有機性成分の混入
（例えば、酸、アルカリ薬液中の有機物、作業環境等か
らの汚染物）により附着する炭素成分についても、従来
技術では除去が十分になしえない。However, the conventional techniques described above cannot adequately remove organic surface contaminants. That is, strong surface deposits cannot be completely removed only by physical cleaning, desorption, and dissolution by dipping the wafer in an organic solvent. Also,
The organic solvent itself used for organic matter removal treatment, or the contamination of organic components (e.g., organic matter in acid or alkaline chemicals, contaminants from the working environment, etc.) during a series of subsequent steps. The adhering carbon components cannot be sufficiently removed using conventional techniques.

ところが、半導体ウェーハに附着した炭素原子は、結晶
、酸化膜中あるいは界面で析出したり、結晶欠陥やＳｉ
Ｃを形成したりして、絶縁耐圧の低下、リーク電流の増
大、接合特性の劣化をもたらすことになる。また、Ｓｉ
Ｃ周辺の結晶歪みには重金属が固定化され、特性不良を
生じるなどの欠点が生じる。However, carbon atoms attached to semiconductor wafers may precipitate in crystals, oxide films, or at interfaces, or cause crystal defects or Si
This results in the formation of C, resulting in a decrease in dielectric strength, an increase in leakage current, and a deterioration in junction characteristics. Also, Si
Heavy metals are immobilized in the crystal distortion around C, resulting in drawbacks such as poor characteristics.

〔発明の目的〕[Purpose of the invention]

本発明は上記の従来技術の欠点に鑑みてなされたもので
、半導体ウェーハの表面に附着した有機性汚染物を効果
的に除去することのできる半導体ウェーハの洗浄装置を
提供することを目的とする。The present invention has been made in view of the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a semiconductor wafer cleaning device that can effectively remove organic contaminants attached to the surface of a semiconductor wafer. .

〔発明の概要〕[Summary of the invention]

上記の目的を実現するため本発明は、半導体ウェーハを
洗浄用の薬液に浸漬するウェーハ洗浄槽に超音波発生器
と紫外線照射器を設け、ウェー７１表面の有機物を容易
に除去できるようにした半導体ウェーハの洗浄装置を提
供するものである。In order to achieve the above object, the present invention provides a wafer cleaning tank in which a semiconductor wafer is immersed in a cleaning chemical solution, which is equipped with an ultrasonic generator and an ultraviolet irradiator, thereby making it possible to easily remove organic matter from the surface of the wafer 71. The present invention provides a wafer cleaning device.

〔発明の実施例〕[Embodiments of the invention]

以下、添付図面を参照して本発明の一実施例を説明する
。第１図は同実施例の構成図である。洗浄さｎるべぎ半
導体ウェーハ１はウェーハキャリア２に保持さｎて、透
明石英製のウェーッ・洗浄槽３に入れられる。洗浄用の
薬液は薬液供給口４゜５．６．７から矢印の如（ウェー
ハ洗浄槽３に供給され、たまった薬液８中に半導体ウェ
ーッ・１が浸漬させられる。また、ウェーハキャリア２
の側面部には複数の紫外線灯９が取り付けらＲ、ウェー
ハ洗浄槽３の下部には超音波発生器１０が設けられる。Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram of the same embodiment. A cleaned semiconductor wafer 1 is held in a wafer carrier 2 and placed in a wafer cleaning tank 3 made of transparent quartz. The cleaning chemical is supplied from the chemical supply port 4°5.6.7 to the wafer cleaning tank 3 as shown by the arrow, and the semiconductor wafer 1 is immersed in the accumulated chemical 8.
A plurality of ultraviolet lamps 9 are attached to the side surface of the wafer cleaning tank 3, and an ultrasonic generator 10 is provided at the bottom of the wafer cleaning tank 3.

また、純水はパルプ１１および導管１２を介してウェー
ハ洗浄槽３に送られる。そして、上記の装置は筐体１３
に収容される。Further, pure water is sent to the wafer cleaning tank 3 via the pulp 11 and the conduit 12. Then, the above device is housed in the housing 13.
be accommodated in.

次に、第１図に示す装置の動作を説明する。一連の洗浄
工程は前述の■〜■の素工径の組合せによりなり、その
際に必要な高純度薬液（例えば７ツ酸、過酸化水素水、
塩酸、アンモニア水等）は薬液供給口４〜７より供給さ
れる。Next, the operation of the apparatus shown in FIG. 1 will be explained. A series of cleaning steps is performed by combining the above-mentioned material diameters, and at that time, the necessary high-purity chemical solutions (e.g., hepatic acid, hydrogen peroxide,
Hydrochloric acid, aqueous ammonia, etc.) are supplied from chemical solution supply ports 4 to 7.

表面に附着した有機性汚染物の除去も、上記の素工径の
ひとつとしてなされる。すなわち、薬液供給ロアより過
硫酸と純水の混液が供給さｎ、紫外線灯９からは紫外線
が照射され、かつ超音波発生器からは超音波振動が与え
らｎる。このようにすると、紫外線による活性化作用と
、超音波振動による物理的洗浄作用および過硫酸（活性
硫酸基）による化学的洗浄作用の相乗によって大ぎな洗
浄効果かえられる。Removal of organic contaminants adhering to the surface is also performed as one of the above-mentioned basic steps. That is, a mixture of persulfuric acid and pure water is supplied from the chemical supply lower, ultraviolet light is irradiated from the ultraviolet lamp 9, and ultrasonic vibration is applied from the ultrasonic generator. In this way, a great cleaning effect can be obtained by the synergy of the activation effect of ultraviolet rays, the physical cleaning effect of ultrasonic vibration, and the chemical cleaning effect of persulfuric acid (active sulfate group).

上記の洗浄作用の概略は下記の通りである。まず、過硫
酸液中の過硫酸イオンは紫外線によって活性硫酸基とな
り、ウェーハ表面の有機性汚染物は励起される。励起さ
ｎた有機物は活性硫酸基により酸化され、炭素は炭酸ガ
スとなって取り除かれる。上記の反応を化学式で示すと
、下記のようになる。An outline of the above-mentioned cleaning action is as follows. First, persulfate ions in the persulfuric acid solution become active sulfuric acid groups by ultraviolet rays, and organic contaminants on the wafer surface are excited. The excited organic matter is oxidized by active sulfuric acid groups, and carbon is removed as carbon dioxide gas. The chemical formula for the above reaction is as follows.

５２ｏ８”−＋ｈ、−→２８０．” Ｒ＋ｈ、−→Ｒ” Ｒ％＋２　ＳＯ４”　＋Ｈ２Ｏ−＋ｎｃ０２＋−・・こ
のような活性化、化学的洗浄作用の際に、超音波撮動が
与えられるので、洗浄作用の均一化、脱塵の容易化が図
られる。52o8"-+h, -→280."R+h,-→R" R%+2 SO4" +H2O-+nc02+-...During such activation and chemical cleaning action, ultrasonic imaging is given, Uniform cleaning action and easier dust removal can be achieved.

なお、こ扛ら素工径の間では薬液の除去等のために、純
水洗浄がなさｎる。純水はバルブ１１および導管１２を
介して供給され、ウェーッ・洗浄槽３を越えて筐体１３
内にあふｎる。Incidentally, cleaning with pure water is not carried out between these raw materials in order to remove the chemical solution, etc. Pure water is supplied via a valve 11 and a conduit 12, and flows beyond the cleaning tank 3 to the housing 13.
Overflowing inside.

第２図は第１図の実施例によってＳｉウェーッ１を処理
したときの汚染除去効果を説明するグラフで、第２図（
ａｊは従来装置によるとぎ、第２図（ｂ）は本実施例に
よるときを示している。第２図（ａ）に示す如（、従来
装置ｆｔ、ＶＣよってＳｉウェーハを洗浄したのち、厚
さ３００へのＳ　＋　０２膜を形成し、その酸化膜の耐
圧を測定すると、耐圧は３〜９Ｍ■伺となる。これに対
し第２図（１））に示す如く、第１図の実施例によって
Ｓｉウェーハを洗浄したのち、厚さ３００ＡのＳｉＯ□
膜を形成し、その耐圧を測定すると８〜９ＭＶ／ｄ程度
の耐圧のものが多（なる。但し、本実施例による洗浄は
、Ｎｌ−１，４０Ｈ：　）ｉｚｏｚ　：　ＨｚＯ＝　１
　：　１＝６混液処理→純水処理→稀ＨＦ処理−純水処
理−−＋ＨＣ１：ｌ−Ｉ２０２　：Ｈ２Ｏ＝　１　：　
１　：　６混液処理→純水処理→Ｉｈ５ｚＯｓ　８釈液
（５〜３０％）処理−→純水処理の順になされるものと
する。FIG. 2 is a graph illustrating the contamination removal effect when Si wafer 1 is treated using the embodiment shown in FIG.
aj shows the case of sharpening by the conventional device, and FIG. 2(b) shows the case of the present embodiment. As shown in FIG. 2(a), after cleaning a Si wafer with conventional equipment ft and VC, an S + 02 film was formed to a thickness of 300 mm and the withstand voltage of the oxide film was measured. On the other hand, as shown in FIG. 2 (1)), after cleaning the Si wafer according to the embodiment shown in FIG.
When a film is formed and its withstand voltage is measured, most of the films have a withstand voltage of about 8 to 9 MV/d.
: 1=6 mixed liquid treatment→pure water treatment→dilute HF treatment−pure water treatment−−+HC1:l−I202:H2O=1:
1:6 mixed solution treatment→pure water treatment→Ih5zOs 8 dilution solution (5 to 30%) treatment−→pure water treatment.

〔発明の効果〕〔Effect of the invention〕

上記の如く本発明によれば、ウェーハ洗浄槽に紫外線照
射器と超音波発生器を設けたので、紫外線による薬液、
汚物の活性化作用と超音波振動による物理的洗浄作用お
よび薬液の化学的洗浄作用を相乗させ、効果的に有機性
の表面汚染物を除去できる半導体ウェーハの洗浄装置を
得ることができる。そして、こｎによってＬＳＩの歩留
り等を向上させることができる。また、本発明に係る装
置によ几ば、他の一連の素工程の中の一工程として有機
性汚染物除去の工程を実行できる。As described above, according to the present invention, since the wafer cleaning tank is provided with an ultraviolet irradiator and an ultrasonic generator, chemical solutions using ultraviolet rays,
It is possible to obtain a semiconductor wafer cleaning device that can effectively remove organic surface contaminants by synergizing the activation effect of dirt, the physical cleaning effect of ultrasonic vibration, and the chemical cleaning effect of a chemical solution. By this means, the yield of LSI can be improved. Furthermore, by using the apparatus according to the present invention, the process of removing organic contaminants can be performed as one process in a series of other elementary processes.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は本発明の一実施例の構成図、第２図は従来装置
による汚染物除去効果と第１図の実施例による汚染物除
去効果を比較して説明するグラフである。 １・・・半導体ウェーハ、２・・・ウェーハギヤリア、
３・・・ウェーハ洗浄槽、４，５，６．７・・・薬液供
給口、８・・・薬液、９・・・紫外線灯、１０・・・超
音ど発生器、１１・・・バルブ、１２・・・導管、１３
・・・筐体。 出願人代理人　猪　股　清FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a graph comparing and explaining the contaminant removal effect of the conventional apparatus and the contaminant removal effect of the embodiment of FIG. 1. 1... Semiconductor wafer, 2... Wafer gearia,
3... Wafer cleaning tank, 4, 5, 6.7... Chemical solution supply port, 8... Chemical solution, 9... Ultraviolet lamp, 10... Ultrasonic generator, 11... Valve , 12... conduit, 13
...Housing. Applicant's agent Kiyoshi Inomata

Claims (1)

【特許請求の範囲】 洗浄薬液を入れるためのウェーハ洗浄槽と、前記洗浄薬
液に浸漬された半導体ウェーハを保持するウェーハキャ
リアと、 前記ウェーハ洗浄槽内に超音波振動を与える超音波発生
器と、 前記半導体ウェーハに紫外線を照射する紫外線照射器と
を備え、半導体ウェーハの表面に耐着した汚染物を除去
するようにした半導体ウェーへの洗浄装置。[Scope of Claims] A wafer cleaning tank for containing a cleaning chemical solution, a wafer carrier holding a semiconductor wafer immersed in the cleaning chemical solution, and an ultrasonic generator for applying ultrasonic vibrations into the wafer cleaning tank. A cleaning device for semiconductor wafers, comprising an ultraviolet irradiator for irradiating the semiconductor wafer with ultraviolet rays, and removing contaminants adhering to the surface of the semiconductor wafer.