JPH07297247A - Method of evaluating substrate - Google Patents
Method of evaluating substrateInfo
- Publication number
- JPH07297247A JPH07297247A JP8142794A JP8142794A JPH07297247A JP H07297247 A JPH07297247 A JP H07297247A JP 8142794 A JP8142794 A JP 8142794A JP 8142794 A JP8142794 A JP 8142794A JP H07297247 A JPH07297247 A JP H07297247A
- Authority
- JP
- Japan
- Prior art keywords
- substrate
- prism
- light
- silicon substrate
- spectrum
- 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.)
- Pending
Links
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- Investigating Or Analysing Materials By Optical Means (AREA)
- Testing Of Optical Devices Or Fibers (AREA)
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、基板の評価方法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate evaluation method.
【０００２】[0002]
【従来の技術とその問題点】半導体集積回路の微細化、
高集積化に伴い、半導体基板の低欠陥化が近年ますます
進行しつつある。このような半導体基板、例えばシリコ
ン基板中の様々な結晶欠陥、低濃度の不純物、シリコン
基板や半導体装置の製造中に導入される汚染は、シリコ
ン基板を用いて製造される半導体装置の性能に大きな影
響を及ぼす。2. Description of the Related Art Miniaturization of semiconductor integrated circuits,
With higher integration, the defect reduction of semiconductor substrates has been increasingly advanced in recent years. Various crystal defects, low-concentration impurities in a semiconductor substrate such as a silicon substrate, and contamination introduced during the manufacture of a silicon substrate or a semiconductor device greatly affect the performance of a semiconductor device manufactured using the silicon substrate. affect.
【０００３】特に、シリコン基板の表層部分には、半導
体装置の様々な構造が形成されるので、この部分につい
ての結晶欠陥や不純物、汚染についての評価は極めて重
要である。In particular, since various structures of a semiconductor device are formed in the surface layer portion of the silicon substrate, it is extremely important to evaluate crystal defects, impurities and contamination in this portion.
【０００４】しかるに、このような半導体基板の表層部
分や表面に付着した汚染物質等を評価する方法は十分で
はなかった。このようなシリコン基板の評価方法として
は、従来は主として２次イオン質量分析法が用いられて
きた。この方法は試料に酸素やアルゴン、セシウムのイ
オンを照射して、試料から放出される２次イオンを質量
分析することにより、試料中に存在する元素を分析する
方法である。However, a method for evaluating such contaminants adhering to the surface layer portion or the surface of the semiconductor substrate has not been sufficient. As a method for evaluating such a silicon substrate, a secondary ion mass spectrometry method has been mainly used conventionally. In this method, a sample is irradiated with oxygen, argon, or cesium ions, and secondary ions emitted from the sample are subjected to mass spectrometry to analyze the elements present in the sample.
【０００５】この方法は感度も良く、深さ方向分析も行
える点で有力であるが、上記のようにイオンを試料に照
射するので必然的に破壊評価になってしまうので、この
評価に用いたシリコン基板は、半導体装置の製造に使用
することはできないという問題点があった。This method is effective in that it has high sensitivity and can perform depth direction analysis, but since it irradiates the sample with ions as described above, destructive evaluation is inevitably carried out, so this method was used for this evaluation. There is a problem that the silicon substrate cannot be used for manufacturing a semiconductor device.
【０００６】他に、半導体基板の表層部分や表面に付着
した汚染物質等を評価する方法としては、オージェ電子
分光法やＸ線光電子分光法等の非破壊評価手法がある
が、いずれも感度的に十分ではなかった。Other methods for evaluating contaminants or the like adhering to the surface layer or surface of a semiconductor substrate include non-destructive evaluation methods such as Auger electron spectroscopy and X-ray photoelectron spectroscopy, all of which are sensitive. Wasn't enough.
【０００７】[0007]
【発明が解決しようとする課題】上記のように、シリコ
ン基板の評価方法は破壊評価手法であったり、十分な感
度が得られない非破壊評価手法であったりした。本発明
は、半導体装置を形成する基板の表層部分の不純物や汚
染、結晶欠陥、シリコン基板の表面に付着した汚染物質
を非破壊で簡便にしかも高感度で評価する方法を提供す
ることを目的とする。As described above, the silicon substrate evaluation method is a destructive evaluation method or a non-destructive evaluation method that does not provide sufficient sensitivity. It is an object of the present invention to provide a method for nondestructively, easily and highly sensitively evaluating impurities and contamination in the surface layer portion of a substrate forming a semiconductor device, crystal defects, and contaminants attached to the surface of a silicon substrate. To do.
【０００８】[0008]
【課題を解決するための手段】上記課題を解決するため
に本発明の第１では、基板の表面にこの基板よりも屈折
率の大きな材質からなるプリズムを接触させ、このプリ
ズムの前記基板と接する側の面で光を全反射させ、前記
プリズムから前記基板側に滲み出た光によって、前記基
板の表層または表面の評価を行なう基板の評価方法を提
供する。In order to solve the above problems, in the first aspect of the present invention, a prism made of a material having a refractive index larger than that of the substrate is brought into contact with the surface of the substrate, and the prism is brought into contact with the substrate. There is provided a substrate evaluation method for totally reflecting light on the side surface and evaluating the surface layer or the surface of the substrate by the light leaking from the prism to the substrate side.
【０００９】望ましくは、前記基板はシリコンであると
良い。望ましくは、前記プリズムはゲルマニウムから形
成されていると良い。望ましくは前記光の波数は、８０
０から１５００ｃｍ-1であると良い。Preferably, the substrate is silicon. Preferably, the prism is made of germanium. Desirably, the wave number of the light is 80
It is good that it is 0 to 1500 cm -1 .
【００１０】本発明の第２では、表面に被検査基板を接
触させた第１のプリズムに第１の光を入射させ、第１の
プリズムで前記第１の光を全反射させ、この全反射させ
た前記第１の光のスペクトルＩs を求めるとともに、表
面に前記基板を接触させずに第２のプリズムに第２の光
を入射させ、前記第２のプリズムの表面で前記第２の光
を全反射させ、この全反射させた前記第２の光のスペク
トルＩ0 を求め、前記スペクトルＩ0 及びＩs から吸光
度スペクトルＡを Ａ＝−ｌｏｇ（Ｉs ／Ｉ0 ） により求める基板の評価方法を提供する。In the second aspect of the present invention, the first light is made incident on the first prism whose surface is in contact with the substrate to be inspected, and the first light is totally reflected by the first prism. The spectrum I s of the first light thus made is obtained, and the second light is made incident on the second prism without bringing the substrate into contact with the surface, and the second light is made incident on the surface of the second prism. Of the substrate, the spectrum I 0 of the totally reflected second light is obtained, and the absorbance spectrum A is obtained from the spectra I 0 and I s by A = −log (I s / I 0 ). Evaluation of the substrate Provide a way.
【００１１】さらに、ＣＺ法で形成した基板の表層また
は表面部分の吸光度スペクトルＡcz及びＦＺで形成した
基板の表層または表面部分の吸光度スペクトルＡfzを求
め、前記吸光度スペクトルＡcz及びＡfzから、前記基板
の表層部分の格子間酸素の吸光度スペクトルＡ0iを Ａ0i＝Ａcz−Ａfz により求めることが望ましい。Further, the absorbance spectra A cz of the surface layer or the surface portion of the substrate formed by the CZ method and the absorbance spectrum A fz of the surface layer or the surface portion of the substrate formed by the FZ are obtained, and from the absorbance spectra A cz and A fz , It is desirable to obtain the absorbance spectrum A 0i of interstitial oxygen in the surface layer portion of the substrate by A 0i = A cz −A fz .
【００１２】望ましくは、前記基板はシリコンであると
良い。望ましくは、前記プリズムはゲルマニウムから形
成されていると良い。望ましくは前記光の波数は、８０
０から１５００ｃｍ-1であると良い。Preferably, the substrate is silicon. Preferably, the prism is made of germanium. Desirably, the wave number of the light is 80
It is good that it is 0 to 1500 cm -1 .
【００１３】また、前記第１と第２のプリズムは、同じ
ものであってもことなるものであっても構わない。望ま
しくは、この第１と第２のプリズムの材質は同じで、さ
らに、同じ形状の方が良い。このとき、反射面が同じで
あるとなお良い。Further, the first and second prisms may be the same or different. Desirably, the first and second prisms are made of the same material and have the same shape. At this time, it is more preferable that the reflecting surfaces are the same.
【００１４】[0014]
【作用】媒質の界面で全反射される光の強度が、界面付
近の媒質中のわずかな不均一性（吸収物質の存在や種々
の表面状態など）によって、敏感に減衰を受けることを
利用した分光法に全反射減衰分光法（ＡＴＲ分光法）が
ある。[Function] The intensity of the light totally reflected at the interface of the medium is sensitively attenuated due to a slight nonuniformity in the medium near the interface (existence of absorbing substances and various surface states). There is total reflection attenuation spectroscopy (ATR spectroscopy) as a spectroscopy.
【００１５】ＡＴＲ分光法では、ある試料内において光
を全反射させるとき、試料の表面の付着物、または、内
部の不純物により吸収され、結果的に試料内を反射する
光のエネルギーは減衰する。この減衰した光のスペクト
ルを求めることにより、試料の表面及び内部の評価をし
ている。In ATR spectroscopy, when the light is totally reflected in a certain sample, it is absorbed by a deposit on the surface of the sample or an internal impurity, and as a result, the energy of the light reflected in the sample is attenuated. The surface and the inside of the sample are evaluated by obtaining the spectrum of this attenuated light.
【００１６】本発明者らが鋭意研究した結果、ある範囲
の波長（波数）の光をシリコンより屈折率の大きな材質
からなるプリズム、例えばゲルマニウムからなるプリズ
ムのシリコンと接する面で全反射させたとき、プリズム
からシリコン側へ光が滲み出し、この滲みだした光はシ
リコン基板の表層の不純物により吸収され、結果的に全
反射した光のエネルギーは減衰する。この減衰した光の
スペクトルを求めることにより、基板の表層の評価をし
ている。As a result of intensive studies by the present inventors, when light of a certain range of wavelength (wave number) is totally reflected by a surface of a prism made of a material having a larger refractive index than silicon, for example, a prism made of germanium, which contacts silicon. Light bleeds from the prism to the silicon side, and the bleeding light is absorbed by impurities on the surface layer of the silicon substrate, and as a result, the energy of the totally reflected light is attenuated. The surface layer of the substrate is evaluated by obtaining the spectrum of this attenuated light.
【００１７】ここで、シリコン表層へ滲みだした光は、
シリコン中に表面から数μｍの深さまでしか浸入しない
のでシリコン基板中の表層より遠い部分での影響を受け
ることなく、シリコン基板の表層部分の評価を高感度で
行なうことができる。Here, the light bleeding to the silicon surface layer is
Since it penetrates into silicon up to a depth of several μm from the surface, the surface layer portion of the silicon substrate can be evaluated with high sensitivity without being affected by the portion farther than the surface layer in the silicon substrate.
【００１８】[0018]
【実施例】以下、本発明のシリコン基板の評価方法の実
施例について、図面を参照しながら詳細に説明する。 実施例１ 図１（ａ）に示されるように、台形断面のゲルマニウム
プリズム１１の表面には何も接触していない状態で、プ
リズムのー斜面から入射光（赤外光）１２を入射させ
た。赤外光はゲルマニウムプリズムの内部で、上面及び
下面で全反射しながら光路で進行する。そして、ゲルマ
ニウムプリズム１１から射出した光（赤外光）１３をフ
ーリエ変換型赤外分光装置で分光し、赤外光のスペクト
ルを求めた。この赤外スペクトルをＩ0 とする。Embodiments of the method for evaluating a silicon substrate according to the present invention will be described below in detail with reference to the drawings. Example 1 As shown in FIG. 1 (a), incident light (infrared light) 12 was made incident from the negative slope of the prism with no contact with the surface of the germanium prism 11 having a trapezoidal cross section. . Infrared light travels in the optical path inside the germanium prism while being totally reflected on the upper and lower surfaces. Then, the light (infrared light) 13 emitted from the germanium prism 11 was dispersed by a Fourier transform infrared spectroscope to obtain the spectrum of infrared light. This infrared spectrum is designated as I 0 .
【００１９】次に、図１（ｂ）に示されるように、シリ
コン基板１４の表面をゲルマニウムプリズム１１に接触
させ、プリズムのー斜面から赤外光１２を入射させた。
赤外光はゲルマニウムプリズム中を進行し、プリズムの
上面及びシリコン基板に接触している下面で全反射しな
がら進行する。そして、ゲルマニウムプリズム１１から
射出した光（赤外光）１５をフーリエ変換型赤外分光装
置で分光し、赤外光のスペクトルを求めた。この赤外ス
ペクトルをＩS とする。Next, as shown in FIG. 1 (b), the surface of the silicon substrate 14 was brought into contact with the germanium prism 11, and the infrared light 12 was made incident from the negative slope of the prism.
The infrared light travels in the germanium prism and travels while being totally reflected by the upper surface of the prism and the lower surface in contact with the silicon substrate. Then, the light (infrared light) 15 emitted from the germanium prism 11 was dispersed by a Fourier transform infrared spectroscope to obtain the spectrum of infrared light. This infrared spectrum is I S.
【００２０】図１（ｂ）において、ゲルマニウムプリズ
ム１１とシリコン基板１４とが接している部分では、赤
外光１５がシリコン基板中に滲みだしている。滲みだし
た赤外光（エバネッセント波）の電界は、図２に示され
るように、シリコン基板中で指数関数的に減衰してい
る。電界が１／ｅに減少する深さを浸入深さといい、シ
リコン基板表層に滲みだした赤外光は、主として浸入深
さまでに存在する赤外吸収体によって吸収されて減衰す
る。このため、ゲルマニウムプリズムから射出する赤外
光も減衰する。従って、ゲルマニウムプリズムからの射
出光のスペクトルにおける減衰量を調べれば、シリコン
基板の表層部分による赤外光の吸収量を知ることができ
る。この実施例では浸入深さは、１０００ｃｍ-1付近で
約３μｍと計算される。In FIG. 1 (b), infrared light 15 bleeds into the silicon substrate at the portion where the germanium prism 11 and the silicon substrate 14 are in contact with each other. The electric field of the exuded infrared light (evanescent wave) is exponentially attenuated in the silicon substrate as shown in FIG. The depth at which the electric field is reduced to 1 / e is called the penetration depth, and infrared light bleeding into the surface layer of the silicon substrate is mainly absorbed and attenuated by the infrared absorber existing up to the penetration depth. Therefore, the infrared light emitted from the germanium prism is also attenuated. Therefore, by examining the amount of attenuation in the spectrum of the light emitted from the germanium prism, the amount of infrared light absorbed by the surface layer of the silicon substrate can be known. In this example, the penetration depth is calculated to be about 3 μm near 1000 cm −1 .
【００２１】これらの赤外スペクトルからＣＺ（チョク
ラルスキ）シリコン基板の表層部分の吸光度スペクトル
は次式で求められる。 ＡCZ＝−ｌｏｇ（ＩS ／Ｉ0 ） このようにして求めたＣＺシリコン基板の表層部分の赤
外吸収スペクトルを図３（ａ）に示す。From these infrared spectra, the absorbance spectrum of the surface layer of the CZ (Czochralski) silicon substrate can be calculated by the following equation. A CZ = −log (I S / I 0 ) The infrared absorption spectrum of the surface layer portion of the CZ silicon substrate thus obtained is shown in FIG.
【００２２】次に、上記と同様にしてゲルマニウムプリ
ズム表面にＦＺ（フローティング・ゾーン）シリコン基
板の表面を接触させ、同様にして表層部分の吸光度スペ
クトルＡFZを求めた。Next, the surface of the FZ (floating zone) silicon substrate was brought into contact with the surface of the germanium prism in the same manner as described above, and the absorbance spectrum A FZ of the surface layer portion was similarly obtained.
【００２３】これらからシリコン基板の表層部分の格子
間酸素の吸光度スペクトルＡOiを次式のようにして求め
た。 ＡOi＝ＡCZ−ＡFZ ここで、ウェハーメーカーから購入した後、７００℃及
び１０００℃の熱処理を行ったシリコン基板を用いた。
このような熱処理を加えると、シリコン基板中には格子
間酸素が過飽和に存在しているために酸素析出物が形成
される。しかし、シリコン基板の表層部分では１０００
℃の熱処理によってシリコン基板の表層付近の格子間酸
素濃度が外方拡散してしまい、格子間酸素濃度が低くな
るので、酸素析出物の密度は低くなっている。この７０
０℃と１０００℃で熱処理したシリコン基板をゲルマニ
ウムプリズムに接触させ、上記と同様にしてシリコン基
板の表層部分の赤外吸収スペクトルを求めた。そして、
ＣＺシリコン基板の表層のスペクトルからＦＺシリコン
基板の表層のスペクトルを引いて、シリコン基板の表層
の格子振動による吸収スペクトルを除去した。From these, the absorbance spectrum A Oi of interstitial oxygen in the surface layer portion of the silicon substrate was determined by the following equation. A Oi = A CZ −A FZ Here, a silicon substrate which was purchased from a wafer maker and then heat-treated at 700 ° C. and 1000 ° C. was used.
When such heat treatment is applied, oxygen precipitates are formed because interstitial oxygen is supersaturated in the silicon substrate. However, the surface layer of the silicon substrate is 1000
Since the interstitial oxygen concentration near the surface layer of the silicon substrate is diffused outward by the heat treatment at ℃, and the interstitial oxygen concentration is reduced, the density of oxygen precipitates is low. This 70
The silicon substrate heat-treated at 0 ° C. and 1000 ° C. was brought into contact with the germanium prism, and the infrared absorption spectrum of the surface layer portion of the silicon substrate was obtained in the same manner as above. And
The absorption spectrum due to lattice vibration of the surface layer of the silicon substrate was removed by subtracting the spectrum of the surface layer of the FZ silicon substrate from the spectrum of the surface layer of the CZ silicon substrate.
【００２４】次に、ウェハーメーカーから買い入れたま
まの熱処理を行なわないシリコン基板の表層の格子間酸
素のスペクトルを求め、熱処理を加えたシリコン基板の
表層のスペクトルからＦＺシリコン基板の表層のスペク
トルを除去したスペクトルから、更に熱処理を加えない
シリコン基板の表層の格子間酸素のスペクトルを引き算
した。ここでは、引き算の係数を任意に変化させて格子
間酸素に起因するピークを除去した。その結果、図３
（ｂ）のようなスペクトルが得られた。このピークの形
状は同様の熱処理を加えたシリコン基板を透過法測定し
たときにみられる酸素析出物に起因するとされるピーク
に類似している。Next, the spectrum of interstitial oxygen in the surface layer of the silicon substrate which has not been subjected to the heat treatment just as purchased from the wafer maker is obtained, and the spectrum of the surface layer of the FZ silicon substrate is removed from the spectrum of the surface layer of the heat treated silicon substrate. From the spectrum thus obtained, the spectrum of interstitial oxygen in the surface layer of the silicon substrate which was not further heat-treated was subtracted. Here, the subtraction coefficient was arbitrarily changed to remove the peak due to interstitial oxygen. As a result,
A spectrum as shown in (b) was obtained. The shape of this peak is similar to the peak attributed to oxygen precipitates observed when a silicon substrate subjected to the same heat treatment is measured by a transmission method.
【００２５】図３（ａ）に示されるように、ＣＺシリコ
ンの表層部分の吸光度スペクトルにおける格子間酸素の
ピーク高は０．８にもなった。この測定に用いたのと同
ーのシリコン基板を、ｐ偏光ブリュースター角法の透過
法測定により、吸光度スペクトルを求めると、図３
（ｃ）に示されるように、スペクトルの格子間酸素のピ
ーク高は０．０８であった。このシリコン基板はウェハ
ーメーカーから購入したままのウェハーであって熱工程
を経ていない。従って、シリコン基板表層の格子間酸素
濃度は、シリコン基板内部と同等と考えられる。As shown in FIG. 3 (a), the peak height of interstitial oxygen in the absorbance spectrum of the surface layer portion of CZ silicon was as high as 0.8. The absorption spectrum of the same silicon substrate used for this measurement was measured by the p-polarization Brewster angle method transmission method.
As shown in (c), the peak height of interstitial oxygen in the spectrum was 0.08. This silicon substrate is a wafer as purchased from a wafer maker and has not undergone a thermal process. Therefore, the interstitial oxygen concentration in the surface layer of the silicon substrate is considered to be equivalent to that in the silicon substrate.
【００２６】即ち、本実施例によって得られたシリコン
基板の表層部分のみについてのスペクトルは透過法によ
るシリコン基板の深さ方向全体のスペクトルの１０倍の
感度を示していることがわかった。That is, it was found that the spectrum of only the surface layer portion of the silicon substrate obtained by this example shows a sensitivity 10 times that of the spectrum of the entire silicon substrate in the depth direction by the transmission method.
【００２７】本実施例では、赤外光の波数が８００から
１５００ｃｍ-1、特に９００から１３００ｃｍ-1であれ
ば、より表層部分を高感度で評価することができること
がわかった。In this example, it was found that when the wave number of infrared light is 800 to 1500 cm -1 , particularly 900 to 1300 cm -1 , the surface layer portion can be evaluated with higher sensitivity.
【００２８】上記実施例の他に、酸素だけでなく炭素も
含有するシリコン基板の表面をゲルマニウムプリズムの
表面に接触させ、上記と同様にしてシリコン基板の表層
部分の赤外吸収スペクトルを求めた。その結果、シリコ
ン基板表層部分に存在する炭素・酸素複合体による吸収
のピークを上記と同様の格子間酸素に起因するピークに
付随した帯域に見ることができた。In addition to the above examples, the surface of the silicon substrate containing not only oxygen but also carbon was brought into contact with the surface of the germanium prism, and the infrared absorption spectrum of the surface layer portion of the silicon substrate was obtained in the same manner as above. As a result, the absorption peak due to the carbon-oxygen complex existing in the surface portion of the silicon substrate could be seen in the band accompanying the peak due to interstitial oxygen similar to the above.
【００２９】また、窒素を含有するシリコン基板の表面
をゲルマニウムプリズムの表面に接触させ、上記と同様
にしてシリコン基板の表層部分の赤外吸収スペクトルを
求めた。その結果、シリコン基板表層部分に存在する窒
素による吸収のピークを得ることができた。Further, the surface of the nitrogen-containing silicon substrate was brought into contact with the surface of the germanium prism, and the infrared absorption spectrum of the surface layer portion of the silicon substrate was obtained in the same manner as above. As a result, a peak of absorption by nitrogen existing in the surface layer of the silicon substrate could be obtained.
【００３０】さらに、中性子を照射した後に３００℃で
熱処理したシリコン基板の表面をゲルマニウムプリズム
の表面に接触させ、上記と同様にしてシリコン基板の表
層部分の赤外吸収スペクトルを求めた。その結果、シリ
コン基板表層部分に存在する点欠陥と酸素の複合体によ
る吸収のピークを中性子照射を行なって熱処理を加えた
シリコン基板の透過法赤外吸収スペクトルで見られるの
と同様のピークを得ることができた。Further, the surface of the silicon substrate which was heat-treated at 300 ° C. after being irradiated with neutrons was brought into contact with the surface of the germanium prism, and the infrared absorption spectrum of the surface layer portion of the silicon substrate was obtained in the same manner as above. As a result, the peak of absorption due to the complex of point defects and oxygen existing in the surface layer of the silicon substrate is obtained as a peak similar to that seen in the transmission infrared absorption spectrum of the silicon substrate subjected to the heat treatment by neutron irradiation. I was able to.
【００３１】実施例２ まず、図４（ａ）に示されるように、断面は両端にくさ
び形状を有し中央部が両端よりも薄くなっている形状
（以下、くさび形状という）のゲルマニウムプリズム４
１の表面に、プリズムのー斜面から赤外光４２を入射さ
せた。赤外光はゲルマニウムプリズムの内部で、上面及
び下面で全反射しながら図に示すような光路で進行す
る。そして、ゲルマニウムプリズムから射出した光４３
をフーリエ変換型赤外分光装置によって分光し、赤外光
のスペクトルを求める。この赤外スペクトルをＩ0 とす
る。Example 2 First, as shown in FIG. 4A, a germanium prism 4 having a wedge-shaped cross section and a central portion thinner than both ends (hereinafter referred to as a wedge shape)
Infrared light 42 was made to enter the surface of No. 1 from the sloping surface of the prism. Infrared light travels in the optical path as shown in the figure while being totally reflected on the upper and lower surfaces inside the germanium prism. Then, the light 43 emitted from the germanium prism
Is dispersed by a Fourier transform infrared spectroscope to obtain the spectrum of infrared light. This infrared spectrum is designated as I 0 .
【００３２】次に、図４（ｂ）に示されるように、半導
体装置の製造工程中で欠陥が導入されたシリコン基板４
４の表面を、くさび形状のゲルマニウムプリズム４１に
接触させ、上記と同様にしてゲルマニウムプリズムのー
斜面から赤外光４２を入射させた。赤外光は、ゲルマニ
ウムプリズム中を進行し、上面及びシリコン基板に接触
している下面で全反射しながら進行する。そして、上記
と同様にゲルマニウムプリズムから射出した赤外光４５
をフーリエ変換型赤外分光装置で分光し、スペクトルを
求めた。この赤外スペクトルをＩS とする。Next, as shown in FIG. 4B, the silicon substrate 4 having defects introduced during the manufacturing process of the semiconductor device.
The surface of No. 4 was brought into contact with the wedge-shaped germanium prism 41, and infrared light 42 was made incident from the negative slope of the germanium prism in the same manner as above. The infrared light travels in the germanium prism and travels while being totally reflected by the upper surface and the lower surface in contact with the silicon substrate. Then, in the same manner as above, the infrared light 45 emitted from the germanium prism
Was analyzed with a Fourier transform infrared spectroscope to obtain a spectrum. This infrared spectrum is I S.
【００３３】そして、実施例１と同様な手順で、シリコ
ン基板の表層の吸光度スペクトルＡOiを求めた。その結
果、シリコン基板中に酸素が存在する場合の透過法測定
のスペクトルに見られるのと同様の帯域にピークを見る
ことができた。Then, by the same procedure as in Example 1, the absorbance spectrum A Oi of the surface layer of the silicon substrate was obtained. As a result, a peak could be seen in a band similar to that seen in the spectrum of the transmission method measurement when oxygen was present in the silicon substrate.
【００３４】実施例２では、プリズムの形状をくさび形
状にしたことにより、プリズム内を進行する光の反射回
数が大幅に増え、より高い感度を提供することができ
た。 実施例３ 図５（ａ）に示されるように、半球状断面で蒲鉾形状の
ゲルマニウムプリズム５１の平坦部を上にして、ゲルマ
ニウムプリズム５１の表面には何も接触していない状態
で、プリズムのー斜面から赤外光５２を入射させた。赤
外光は、ゲルマニウムプリズムの上面全反射した後プリ
ズム外に射出される。この射出光５３をフーリエ変換型
赤外分光装置で分光した。In the second embodiment, since the prism is wedge-shaped, the number of reflections of light traveling in the prism is significantly increased, and higher sensitivity can be provided. Example 3 As shown in FIG. 5 (a), the flat part of a hemp-shaped germanium prism 51 having a hemispherical cross section was faced up, and nothing was in contact with the surface of the germanium prism 51. -Infrared light 52 was made incident from the slope. The infrared light is totally reflected on the upper surface of the germanium prism and then emitted to the outside of the prism. The emitted light 53 was separated by a Fourier transform infrared spectroscope.
【００３５】次に、図５（ｂ）に示されるように、ゲル
マニウムプリズム５１上に、半導体装置の製造工程にお
いて表面に有機物５５が付着したシリコン基板５４の表
面を接触させた。そして、フーリエ変換型赤外分光装置
によってプリズムからの射出光５６を分光した。Next, as shown in FIG. 5B, the surface of the silicon substrate 54 having the organic substance 55 attached to the surface thereof was brought into contact with the germanium prism 51 in the manufacturing process of the semiconductor device. Then, the light 56 emitted from the prism was dispersed by a Fourier transform infrared spectroscope.
【００３６】そして、実施例１と同様にしてシリコンの
表面の赤外吸光度スペクトルを求めた。このとき、３０
００ｃｍ-1付近、また、１２６０ｃｍ-1付近に、それぞ
れ図３（ｄ）、図３（ｅ）に示されるような吸収帯が見
られた。この吸収帯は、通常シリコンの格子振動では見
られない波数域にあるため、この吸収帯がシリコン基板
の表面に付着した有機汚染物質のスペクトルであること
がわかる。Then, the infrared absorption spectrum of the silicon surface was obtained in the same manner as in Example 1. At this time, 30
00cm around -1 Furthermore, in the vicinity of 1260 cm -1, respectively Figure 3 (d), the absorption band as shown in FIG. 3 (e) was observed. Since this absorption band is in a wave number range that is not usually found in lattice vibration of silicon, it can be seen that this absorption band is a spectrum of organic contaminants attached to the surface of the silicon substrate.
【００３７】なお、本発明は上記実施例に限定されるも
のではない。シリコン基板表面に接触させるプリズムの
材質としては、シリコンよりも屈折率が大きく、評価に
用いる波長の光が透過するような材質であれば、例えば
ＩｎＳｂやＴｅ並びにＬｉを拡散したＧａＡｓ等を用い
ることができる。また、誘電体であっても屈折率がシリ
コンよりも大きく評価に用いる波長の光が透過すれば使
用可能である。The present invention is not limited to the above embodiment. As the material of the prism that comes into contact with the surface of the silicon substrate, InSb, Te, Li diffused GaAs, or the like may be used as long as the material has a refractive index larger than that of silicon and transmits light of a wavelength used for evaluation. You can Further, even a dielectric material can be used if it has a refractive index larger than that of silicon and transmits light of a wavelength used for evaluation.
【００３８】プリズム形状としては台形断面や蒲鉾形
状、くさび形状以外にも平行四辺形や球形等、シリコン
表面と接触させて全反射を起こさせることができれば如
何なる形状のプリズムでも用いることができる。As the prism shape, in addition to a trapezoidal cross section, a kamaboko shape, a wedge shape, a parallelogram, a spherical shape, or any other shape can be used as long as the prism can be brought into contact with the silicon surface to cause total reflection.
【００３９】また、評価法としては、赤外吸収の他にPh
otoluminescence やラマン散乱分光等の光を用いた評価
法であれば本発明による評価法を適用することができ
る。評価対象として実施例では、基板はシリコンを用い
たが、ガリウムヒ素等他の半導体基板、またはアルミニ
ウム等の金属基板、さらには酸化シリコン基板等でも構
わない。また、これらの材料からなる単結晶、多結晶、
非晶質基板、特に単結晶基板に対して本発明を用いて欠
陥等の検出を行うことが好ましい。さらに、半導体基板
に限らなくても、表層の評価を行うことを目的とするも
のであれば良い。As the evaluation method, in addition to infrared absorption, Ph
The evaluation method according to the present invention can be applied to any evaluation method using light such as otoluminescence or Raman scattering spectroscopy. Although silicon is used as the substrate in the examples for evaluation, other semiconductor substrates such as gallium arsenide, metal substrates such as aluminum, and silicon oxide substrates may be used. In addition, single crystals, polycrystals made of these materials,
It is preferable to detect defects and the like by using the present invention on an amorphous substrate, particularly a single crystal substrate. Further, it is not limited to the semiconductor substrate as long as the object is to evaluate the surface layer.
【００４０】また、実施例中に示したように、シリコン
基板中の格子間酸素や炭素、窒素等の不純物、結晶欠
陥、あるいはシリコン基板表面に付着した有機物汚染の
他に、半導体装置の製造工程で半導体装置を形成するた
めに、意図的にシリコン基板表層に導入された不純物、
即ち、シリコン基板の表面に接触させるプリズム中を透
過する光の帯域内にスペクトルを持つものであれば種々
評価することができる。Further, as shown in the embodiments, in addition to impurities such as interstitial oxygen, carbon, nitrogen, etc. in the silicon substrate, crystal defects, or organic contamination attached to the surface of the silicon substrate, a semiconductor device manufacturing process is also performed. Impurities intentionally introduced into the surface layer of the silicon substrate to form a semiconductor device with
That is, various evaluations can be made as long as they have a spectrum within the band of light that passes through the prism that is in contact with the surface of the silicon substrate.
【００４１】[0041]
【発明の効果】本発明の方法によれば、基板の表層部分
の不純物、結晶欠陥、汚染物質等及び基板の表面の付着
物等を簡便に非破壊かつ高感度で評価することができ
る。According to the method of the present invention, impurities, crystal defects, contaminants and the like on the surface layer of the substrate and deposits on the surface of the substrate can be evaluated easily and non-destructively and with high sensitivity.
【図１】 本発明のシリコン基板の評価方法の一実施例
を示す模式図。FIG. 1 is a schematic view showing an embodiment of a silicon substrate evaluation method of the present invention.
【図２】 ゲルマニウムプリズムからシリコン基板に滲
み出した光のシリコン表面からの深さ方向の電界強度の
分布図。FIG. 2 is a distribution diagram of electric field intensity of light oozing from a germanium prism onto a silicon substrate in a depth direction from a silicon surface.
【図３】 本発明の効果を示す特性図。FIG. 3 is a characteristic diagram showing the effect of the present invention.
【図４】 本発明のシリコン基板の評価方法の他の実施
例を示す模式図。FIG. 4 is a schematic view showing another embodiment of the silicon substrate evaluation method of the present invention.
【図５】 本発明のシリコン基板の評価方法の他の実施
例を示す模式図。FIG. 5 is a schematic view showing another embodiment of the silicon substrate evaluation method of the present invention.
１１・・・ゲルマニウムプリズム １２・・・入射光 １３・・・プリズムからの出射光 １４・・・シリコン基板 １５・・・プリズムにシリコン表面を接触させたときの
射出光 ４１・・・ゲルマニウムプリズム ４２・・・入射光 ４３・・・プリズムからの出射光 ４４・・・半導体装置の製造工程中で欠陥が導入された
シリコン基板 ４５・・・プリズムにシリコン表面を接触させたときの
射出光 ４６・・・補強材 ５１・・・ゲルマニウムプリズム ５２・・・入射光 ５３・・・プリズムからの出射光 ５４・・・半導体製造工程中で汚染されたシリコン基板 ５５・・・シリコン基板表面に付着した有機物 ５６・・・プリズムにシリコン表面を接触させたときの
射出光11 ... Germanium prism 12 ... Incoming light 13 ... Emitting light from prism 14 ... Silicon substrate 15 ... Emitting light when a silicon surface is brought into contact with a prism 41 ... Germanium prism 42・ ・ ・ Incoming light 43 ・ ・ ・ Emission light from prism 44 ・ ・ ・ Silicon substrate in which defects are introduced in the manufacturing process of a semiconductor device 45 ・ ・ ・ Emission light when the silicon surface is brought into contact with the prism 46 ..Reinforcing material 51 ... Germanium prism 52 ... Incoming light 53 ... Emitting light from prism 54 ... Silicon substrate contaminated during semiconductor manufacturing process 55 ... Organic substances adhering to silicon substrate surface 56: Light emitted when the silicon surface is brought into contact with the prism
Claims (6)
きな材質からなるプリズムを接触させ、このプリズムの
前記基板と接する側の面で光を全反射させ、前記プリズ
ムから前記基板側に滲み出た光によって、前記基板の表
層または表面の評価を行なうことを特徴とする基板の評
価方法。1. A prism made of a material having a refractive index larger than that of the substrate is brought into contact with the surface of the substrate, and light is totally reflected by a surface of the prism that is in contact with the substrate, and bleeds from the prism to the substrate side. A method for evaluating a substrate, characterized in that the surface or the surface of the substrate is evaluated by the emitted light.
リズムに第１の光を入射させ、第１のプリズムで前記第
１の光を全反射させ、この全反射させた前記第１の光の
スペクトルＩs を求めるとともに、 表面に前記基板を接触させずに第２のプリズムに第２の
光を入射させ、前記第２のプリズムの表面で前記第２の
光を全反射させ、この全反射させた前記第２の光のスペ
クトルＩ0 を求め、前記スペクトルＩ0 及びＩs から吸
光度スペクトルＡを求めることを特徴とする基板の評価
方法。2. The first light is made incident on a first prism whose surface is in contact with a substrate to be inspected, the first light is totally reflected by the first prism, and the first light is totally reflected. While obtaining the spectrum I s of the light, the second light is made incident on the second prism without bringing the substrate into contact with the surface, and the second light is totally reflected on the surface of the second prism, A substrate evaluation method, characterized in that a spectrum I 0 of the totally reflected second light is obtained, and an absorbance spectrum A is obtained from the spectra I 0 and I s .
部分の吸光度スペクトルＡcz及びＦＺで形成した基板の
表層または表面部分の吸光度スペクトルＡfzを求め、前
記吸光度スペクトルＡcz及びＡfzから、前記基板の表層
部分の格子間酸素の吸光度スペクトルＡ0iを求めること
を特徴とする請求項２記載の基板の評価方法。3. The absorption spectrum A cz of the surface layer or the surface portion of the substrate formed by the CZ method and the absorption spectrum A fz of the surface layer or the surface portion of the substrate formed by the FZ are determined, and from the absorption spectra A cz and A fz , The substrate evaluation method according to claim 2, wherein an absorbance spectrum A 0i of interstitial oxygen in the surface layer portion of the substrate is obtained.
する請求項１または２記載の基板の評価方法。4. The method for evaluating a substrate according to claim 1, wherein the substrate is silicon.
されていることを特徴とする請求項１または２記載の基
板の評価方法。5. The substrate evaluation method according to claim 1, wherein the prism is made of germanium.
ｍ-1であることを特徴とする請求項５記載の基板の評価
方法。6. The wave number of the light is 800 to 1500 c
The substrate evaluation method according to claim 5, wherein m -1 .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8142794A JPH07297247A (en) | 1994-04-20 | 1994-04-20 | Method of evaluating substrate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8142794A JPH07297247A (en) | 1994-04-20 | 1994-04-20 | Method of evaluating substrate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07297247A true JPH07297247A (en) | 1995-11-10 |
Family
ID=13746078
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8142794A Pending JPH07297247A (en) | 1994-04-20 | 1994-04-20 | Method of evaluating substrate |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07297247A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012137480A1 (en) * | 2011-04-04 | 2012-10-11 | 信越化学工業株式会社 | Method for measuring carbon concentration in polycrystalline silicon |
| JP2012243975A (en) * | 2011-05-20 | 2012-12-10 | Sumco Corp | Evaluation method and manufacturing method of silicon wafer |
| JP2014092411A (en) * | 2012-11-01 | 2014-05-19 | Toyota Motor Corp | EVALUATION METHOD OF SiC SINGLE CRYSTAL AND METHOD FOR MANUFACTURING SiC SINGLE CRYSTAL USING THE SAME |
-
1994
- 1994-04-20 JP JP8142794A patent/JPH07297247A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012137480A1 (en) * | 2011-04-04 | 2012-10-11 | 信越化学工業株式会社 | Method for measuring carbon concentration in polycrystalline silicon |
| CN103477207A (en) * | 2011-04-04 | 2013-12-25 | 信越化学工业株式会社 | Method for measuring carbon concentration in polycrystalline silicon |
| US8963070B2 (en) | 2011-04-04 | 2015-02-24 | Shin-Etsu Chemical Co., Ltd. | Method for measuring carbon concentration in polycrystalline silicon |
| JP2012243975A (en) * | 2011-05-20 | 2012-12-10 | Sumco Corp | Evaluation method and manufacturing method of silicon wafer |
| JP2014092411A (en) * | 2012-11-01 | 2014-05-19 | Toyota Motor Corp | EVALUATION METHOD OF SiC SINGLE CRYSTAL AND METHOD FOR MANUFACTURING SiC SINGLE CRYSTAL USING THE SAME |
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