JP2525894B2 - Fluorescence characteristic inspection device for semiconductor samples - Google Patents
Fluorescence characteristic inspection device for semiconductor samplesInfo
- Publication number
- JP2525894B2 JP2525894B2 JP1089480A JP8948089A JP2525894B2 JP 2525894 B2 JP2525894 B2 JP 2525894B2 JP 1089480 A JP1089480 A JP 1089480A JP 8948089 A JP8948089 A JP 8948089A JP 2525894 B2 JP2525894 B2 JP 2525894B2
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- Japan
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- sample
- image
- photoluminescence
- distribution
- light source
- Prior art date
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- Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
Description
本発明は、半導体試料の螢光特性を検査するための装
置に係り、特に、発光ダイオード（LED）、レーザダイ
オード（LD）、電界効果トランジスタ（FET）、フオト
ダイオード（PD）、光学電気集積素子（OEIC）、集積素
子（IC）等に使用されるGaAsウエハ等の半導体ウエハの
品質を評価する際に用いるのに好適な、試料から発生す
るフオトルミネツセンスの空間的な強度分布画像や寿命
分布画像又はその相関分布画像を得ることが可能な、半
導体試料の螢光特性検査装置に関するものである。The present invention relates to a device for inspecting a fluorescent property of a semiconductor sample, and more particularly to a light emitting diode (LED), a laser diode (LD), a field effect transistor (FET), a photo diode (PD), an optoelectronic integrated device. (OEIC), a spatial intensity distribution image and lifetime of photoluminescence generated from a sample, which is suitable for evaluating the quality of semiconductor wafers such as GaAs wafers used for integrated devices (ICs) The present invention relates to an apparatus for inspecting fluorescence characteristics of a semiconductor sample, which can obtain a distribution image or a correlation distribution image thereof.
LED、LD、FET、PD、OEIC、IC等の製造に用いられるGa
Asウエハの品質は、これらの製造業者にとつて最大の問
題であり、現状では決して安心できるものではない。 一般に、半導体結晶に禁止帯幅よりも大きなエネルギ
ーを持つ光ビームを照射して価電子帯から電子を励起す
ると、励起された電子が再結合でエネルギーを失う過程
で螢光が観測され、この発光がフオトルミネツセンスと
呼ばれている。このフオトルミネツセンスにおける螢光
の寿命は、結晶の品質、表面処理、表面の歪、疵等によ
つても決まる。従つて、研磨→エツチングと加工工程が
進むに従つて、表面の再結合中心が減少し、螢光寿命が
長くなる場合もある。これは、表面再結合速度を見てい
ることに相当する。一般的には、螢光寿命が変化するの
は、結晶の品質、結晶欠陥、表面状態、表面処理等の影
響のためであり、これらの状況が良好な、即ち品質の良
いウエハは、第７図に実線Ａで示す如く螢光寿命が長く
なるのに対して、品質の低いウエハは、同じく第７図に
実線Ｂで示す如く、螢光寿命が短くなつている。従つ
て、GaAsウエハの品質評価に際しては、その螢光寿命を
測定することが重要である。 又、GaAsウエハの品質は、螢光寿命だけでなく、螢光
効率（量子効率、螢光の絶対値即ち螢光強度）も重要で
ある。通常は、第７図に示すように、螢光効率と寿命は
相関があるが、そうでない場合もあり得るので、螢光強
度を測ることも重要である。 フオトルミネツセンスを利用して結晶の品質を調べる
ための従来の装置は、試料に波長λ１の連続光（DC光）
を照射し、発生する波長λ２（＞λ１）のフオトルミネ
ツセンスの強度分布から、試料の評価を行うものであつ
た。 又、モード同期パルスレーザ又は半導体レーザのパル
ス光を試料に当て、サンプリング型ストリークカメラを
用いて、発生したフオトルミネツセンスの螢光寿命を測
定する技術も提案されている。Ga used for manufacturing LEDs, LDs, FETs, PDs, OEICs, ICs, etc.
As-wafer quality is the biggest issue for these manufacturers and is by no means reassuring at the moment. In general, when a semiconductor crystal is irradiated with a light beam having an energy larger than the band gap to excite electrons from the valence band, fluorescence is observed in the process of the excited electrons losing energy due to recombination, and this emission Is called Photoluminescence. The lifetime of fluorescence in this photoluminescence is also determined by the quality of the crystal, surface treatment, surface distortion, flaws, and the like. Therefore, the recombination centers on the surface may decrease and the fluorescence life may become longer as the polishing → etching and processing steps proceed. This corresponds to looking at the surface recombination rate. In general, the change in fluorescence lifetime is due to the influence of crystal quality, crystal defects, surface condition, surface treatment, etc., and wafers in these favorable conditions, that is, high quality wafers, While the fluorescence life is extended as indicated by the solid line A in the figure, the low quality wafer has a shorter fluorescence lifetime as indicated by the solid line B in FIG. Therefore, it is important to measure the fluorescence lifetime when evaluating the quality of GaAs wafers. Further, not only the fluorescence lifetime but also the fluorescence efficiency (quantum efficiency, absolute value of fluorescence, that is, fluorescence intensity) is important for the quality of a GaAs wafer. Normally, as shown in FIG. 7, there is a correlation between the fluorescence efficiency and the life, but there are cases where it is not so that it is also important to measure the fluorescence intensity. A conventional device for investigating crystal quality using photoluminescence is continuous light (DC light) of wavelength λ1 on the sample.
The sample was evaluated from the intensity distribution of photoluminescence of the wavelength λ2 (> λ1) that was generated by irradiating the sample. There is also proposed a technique of irradiating a sample with pulsed light of a mode-locked pulse laser or a semiconductor laser and measuring the fluorescence lifetime of the generated photoluminescence by using a sampling streak camera.
しかしながら、測定結果は単一の測定点についてのみ
しか得られないので、局所的な欠陥の検出が困難である
等の問題点を有していた。 本発明は、前記従来の問題点を解消するべくなされた
もので、試料から発生するフオトルミネツセンスの螢光
強度や螢光寿命、又はその相関の空間的な分布画像を、
深さ方向の分解能を持つて高速で得ることが可能な、半
導体試料の螢光特性検査装置を提供することを課題とす
る。However, since the measurement result can be obtained only for a single measurement point, there is a problem that it is difficult to detect a local defect. The present invention has been made to solve the conventional problems, the fluorescence intensity and fluorescence lifetime of photoluminescence generated from the sample, or a spatial distribution image of the correlation,
An object of the present invention is to provide a fluorescence characteristic inspection device for a semiconductor sample, which has a resolution in the depth direction and can be obtained at high speed.
本発明は、半導体試料の螢光特性検査装置において、
第１図にその基本構成を例示する如く、試料10を励起す
るための、連続的且つ周期的に強度変調された光を発生
する変調光源12と、該変調光源12の光を試料10に照射す
る照射光学系14と、試料10の測定位置を２次元方向に移
動するための移動手段（図ではＸ−Ｙステージ16）と、
試料10から発生するフオトルミネツセンスを抽出して検
出器に導く集光光学系18と、前記フオトルミネツセンス
を検出するための高速光検出器20と、前記変調光源12の
発光の位相と高速光検出器20の出力信号の位相差を求め
る位相比較器21と、試料測定位置を２次元方向に移動し
ながら、各測定点における前記位相差を解析・処理し
て、フオトルミネツセンスの空間的な強度分布や寿命分
布、又はその相関分布を求める信号処理装置22と、求め
られたフオトルミネツセンスの強度分布や寿命分布画像
を表示する画像表示装置24と、前記高速光検出器20の入
力結像面に設けられたアパーチヤ62とを備え、前記光学
系を試料深さ方向の分解能を有する共焦点光学系とする
ことにより、前記課題を達成したものである。 又、前記高速光検出器の直前に分光手段を設け、波長
毎の空間的な強度分布や寿命分布、又はその相関分布が
求められるようにしたものである。 更に、前記変調光源とは別に試料を照射する落射照明
光源と、試料からの反射光が導かれるTVカメラとを備
え、該TVカメラで撮像した画像を前記フオトミネツセン
スの強度分布や寿命分布画像と重畳して、前記画像表示
装置に表示するようにしたものである。 又、前記落射照明光源に試料の吸収波長に合わせた波
長フイルタを設け、試料を全面照射して、発生するフオ
トルミネツセンス画像を所定の波長フイルタを介して、
前記TVカメラにより撮像し、２次元のフオトミネツセン
ス強度分布を求めるようにしたものである。 更に、試料の裏面側に透過照明のための光源及び光学
系を設け、試料の透過面像をTVカメラ又は高速光検出器
により取得して、フオトルミネツセンスの強度分布や寿
命分布画像と重畳表示するようにしたものである。 又、前記高速光検出器の前に設けられた分光手段によ
り、試料の非線形性による第２高調波成分を抽出し、試
料を走査して非線形光学特性画像を得るようにしたもの
である。The present invention provides a fluorescence characteristic inspection device for semiconductor samples,
As illustrated in the basic configuration in FIG. 1, a modulation light source 12 for exciting the sample 10 to generate light whose intensity is modulated continuously and periodically, and the sample 10 is irradiated with the light of the modulation light source 12. An irradiation optical system 14 for moving, a moving means (XY stage 16 in the figure) for moving the measurement position of the sample 10 in a two-dimensional direction,
A focusing optical system 18 for extracting photoluminescence generated from the sample 10 and guiding it to a detector, a high-speed photodetector 20 for detecting the photoluminescence, and a phase of light emitted from the modulated light source 12. A phase comparator 21 for obtaining the phase difference of the output signal of the high-speed photodetector 20 and the phase difference at each measurement point are analyzed and processed while moving the sample measurement position in the two-dimensional direction to detect photoluminescence. A signal processing device 22 that obtains a spatial intensity distribution, a life distribution, or a correlation distribution thereof, an image display device 24 that displays the obtained intensity distribution and life distribution image of photoluminescence, and the high-speed photodetector 20. And the aperture 62 provided on the input image forming plane, and the optical system is a confocal optical system having a resolution in the depth direction of the sample. Further, a spectroscopic means is provided immediately in front of the high-speed photodetector so that a spatial intensity distribution and lifetime distribution for each wavelength, or a correlation distribution thereof can be obtained. Furthermore, an epi-illumination light source that illuminates the sample separately from the modulated light source, and a TV camera that guides the reflected light from the sample are provided, and the image captured by the TV camera is used for the intensity distribution and lifetime distribution of the photoluminescence. The image is superimposed and displayed on the image display device. Further, the epi-illumination light source is provided with a wavelength filter matched to the absorption wavelength of the sample, the sample is irradiated over the entire surface, a photoluminescence image generated is passed through a predetermined wavelength filter,
A two-dimensional photoluminescence intensity distribution is obtained by imaging with the TV camera. In addition, a light source and optical system for transmitted illumination is provided on the back side of the sample, and the image of the transmitted surface of the sample is acquired by a TV camera or high-speed photodetector, and superimposed on the intensity distribution and lifetime distribution image of photoluminescence. It is intended to be displayed. Further, the second harmonic component due to the non-linearity of the sample is extracted by the spectroscopic means provided in front of the high-speed photodetector, and the sample is scanned to obtain a non-linear optical characteristic image.
本発明にかかる螢光特性検査装置では、連続的且つ周
期的に強度変調された光を発生する変調光源12を用いて
試料10を励起し、該変調光源12の発光の位相と高速光検
出器20の出力信号の位相差を求め、試料測定位置を２次
元方向に移動しながら、各測定点における前記位相差を
解析・処理して、フオトルミネツセンスの空間的な強度
分布や寿命分布、又はその相関分布を求めるようにして
いる。従つて、試料の螢光強度及び寿命を同時に高速で
測定することができ、GaAsウエハ等の品質を正確に評価
することが可能となる。更に、該螢光強度や寿命、又は
その相関の空間的な分布像が得られるので、局所的な欠
陥等も容易に検査することができる。 更に、前記高速光検出器20又は分光手段の入力結像面
にアパーチヤを設けて、前記光学系を共焦点光学系とし
ているので、合焦点面の情報だけが得られ、試料深さ方
向についても分解能が得られる。 又、前記高速光検出器20の直前に分光手段を設けた場
合には、フオトルミネツセンスの波長毎の空間的な強度
分布や寿命分布、又はその相関分布を得ることが可能と
なり、特に、波長によつて螢光寿命が異なる試料を検査
する際に好適である。 更に、前記変調光源とは別に試料を照射する落射照明
光源と、試料からの反射光が導かれるTVカメラとを備
え、該TVカメラで撮像した画像を前記フオトミネツセン
スの強度分布や寿命分布画像と重畳して、前記画像表示
装置に表示するようにした場合には、試料上の変調光の
位置を確認したり、測定領域の状態をモニタすることが
できる。 又、前記落射照明光源に試料の吸収波長に合わせた波
長フイルタを設け、試料を全面照射して、発生するフオ
トルミネツセンス画像を所定の波長フイルタを介して、
前記TVカメラにより撮像し、２次元のフオトミネツセン
ス強度分布を求めるようにすることができる。 更に、試料の裏面側に透過照明のための光源及び光学
系を設け、試料の透過画像をTVカメラ又は高速光検出器
により取得して、フオトルミネツセンスの強度分布や寿
命分布画像と重畳表示することができる。 又、前記高速光検出器の前に設けられた分光手段によ
り、試料の非線形性による第２高調波成分を抽出し、試
料を走査して非線形光学特性画像を得ることもできる。In the fluorescence property inspection apparatus according to the present invention, the sample 10 is excited by using the modulation light source 12 that continuously and periodically generates the intensity-modulated light, and the phase of light emission of the modulation light source 12 and the high-speed photodetector. Obtaining the phase difference of the 20 output signals, analyzing and processing the phase difference at each measurement point while moving the sample measurement position in the two-dimensional direction, the spatial intensity distribution and life distribution of photoluminescence, Alternatively, the correlation distribution thereof is obtained. Therefore, the fluorescence intensity and the life of the sample can be simultaneously measured at high speed, and the quality of the GaAs wafer or the like can be accurately evaluated. Furthermore, since a spatial distribution image of the fluorescence intensity, the lifetime, or the correlation thereof can be obtained, local defects and the like can be easily inspected. Furthermore, since an aperture is provided on the input image forming surface of the high-speed photodetector 20 or the spectroscopic means, and the optical system is a confocal optical system, only information on the in-focus surface can be obtained, and also in the sample depth direction. Resolution is obtained. Further, when the spectroscopic means is provided immediately before the high-speed photodetector 20, it becomes possible to obtain a spatial intensity distribution and life distribution for each wavelength of photoluminescence, or a correlation distribution thereof, in particular, It is suitable for inspecting a sample whose fluorescence lifetime varies depending on the wavelength. Furthermore, an epi-illumination light source that illuminates the sample separately from the modulated light source, and a TV camera that guides the reflected light from the sample are provided, and the image captured by the TV camera is used for the intensity distribution and lifetime distribution of the photoluminescence. When the image is superimposed and displayed on the image display device, the position of the modulated light on the sample can be confirmed and the state of the measurement region can be monitored. Further, the epi-illumination light source is provided with a wavelength filter matched to the absorption wavelength of the sample, the sample is irradiated over the entire surface, a photoluminescence image generated is passed through a predetermined wavelength filter,
A two-dimensional photoluminescence intensity distribution can be obtained by imaging with the TV camera. In addition, a light source and an optical system for transmitted illumination are installed on the back side of the sample, and the transmitted image of the sample is acquired by a TV camera or high-speed photodetector, and the intensity distribution of the photoluminescence and the life distribution image are superimposed and displayed. can do. It is also possible to extract the second harmonic component due to the non-linearity of the sample by the spectroscopic means provided in front of the high-speed photodetector and scan the sample to obtain the non-linear optical characteristic image.
以下図面を参照して、半導体ウエハ評価装置に適用し
た、本発明に係る螢光特性検査装置の実施例を詳細に説
明する。 本発明の第１実施例は、第１図に示した如く、GaAs半
導体ウエハ等の試料10を励起するための、正弦波状に強
度変調された光を発生する変調光源12と、該変調光源12
の光を試料10に照射する照射光学系14と、前記変調光源
12に対する試料10の位置を２次元方向に移動させること
によつて、試料10の測定位置（光照射位置）を２次元方
向に移動するためのＸ−Ｙステージ16と、試料10から発
生するフオトルミネツセンスを抽出して検出器に導くた
めの、ビームスプリツタ18A、フオトルミネツセンスの
波長成分を抽出するためのフイルタ18B及びレンズ18Cを
含む集光光学系18と、前記フオトルミネツセンスを検出
するための高速光検出器20と、前記変調光源12の発光の
位相と高速光検出器の出力信号の位相差を求める位相比
較器21と、前記Ｘ−Ｙステージ16を移動することによつ
て、試料測定位置を２次元方向に移動しながら、例えば
格子状の各測定点（第２図参照）における前記位相差を
解析・処理して、フオトルミネツセンスの空間的な強度
分布及び寿命分布、又はその相関分布を求める信号処理
装置22と、該信号処理装置22によつて得られた空間的な
強度分布画像及び寿命分布画像、又はその相関分布画像
を表示する画像表示装置24とから構成されている。 前記変調光源12としては、例えば波長600〜680nm程度
の正弦波状に強度変調された光を安定して発振可能なレ
ーザダイオード（LD）又は発光ダイオード（LED）を用
いることができる。該変調光源12の発光を検出する方法
としては、例えば変調光源12からの光を分岐し、その一
方の光をアバランシユフオトダイオード（APD）等の高
速フオトダイオードで電気信号に変化することができ
る。 前記高速光検出器20としては、例えば高速フオトダイ
オードや光電子増倍管を用いて、構成を簡略にすること
ができる。 前記信号処理装置22における螢光波形に関する情報の
解析及び処理は、次のようにして行われる。 励起光を正弦波で変調することによつて、試料10を次
式で示される正弦波ｌ（ｔ）で励起すると、その螢光波
形ｆ（ｔ）は、位相がφ＝tan-1（ωτ）だけずれた正
弦波となる。又、フオトルミネツセンスの強度も螢光波
形ｆ（ｔ）の平均パワーから求められる。 ｌ（ｔ）＝L1・sin（ωτ）＋L0 …（１） このようにして求められた螢光寿命及び螢光強度が、
前記画像表示装置24に空間的分布画像として表示され
る。螢光寿命の表示画像の一例を第３図に示す。この第
３図においては、螢光寿命τの分布が、例えば濃淡によ
つて表わされている。 なお、螢光強度及び寿命を画像化するに際しては、白
黒濃度で表示する他、カラー画像で色を変えて表示した
り、あるいは３次元表示を行うことも可能である。又、
螢光寿命に、第２次成分τ２、第３次成分τ３もある場
合には、例えば１次成分τ１のみを緑でマツピングし、
１次及び２次成分τ１、τ２を赤でマツピングし、１
次、２次及び３次成分τ１、τ２、τ３を黄でマツピン
グすることができる。又、１次成分τ１を赤とし、２次
成分τ２を緑とし、３次成分τ３を青とし、順次重ねる
ことによつて、結果的に、１次成分τ１を赤、２次成分
τ２を黄、３次成分τ３を白で表示することも可能であ
る。更に、画像表示に際しては、適宜スムージング処理
を行つて、見易くすることも可能である。 又、信号処理装置22は、異なる強度分布画像及び寿命
分布画像の間での相関、例えば比を求める等の演算を行
い、演算結果（即ち相関分布画像）につき表示すること
もできる。 次に、第４図を参照して、本発明の第１実施例を詳細
に説明する。 この第２実施例は、前記第１実施例と同様の、変調光
源12と、照射光学系14と、Ｘ−Ｙステージ16と、集光光
学系18と、高速光検出器20と、位相比較器21と、信号処
理装置22と、画像表示装置24とを備えた半導体ウエハ評
価装置において、更に、前記高速光検出器20の直前に、
試料10から発生するフオトルミネツセンスを分光する分
光器60を設け、高速光検出器20で、波長毎の螢光波形を
検出して、波長毎の空間的な強度分布画像及び寿命分布
画像、又はその相関分布画像が得られるようにしたもの
である。 この第２実施例によれば、波長情報も同時に測定する
ことができ、例えば第５図に示す如く、波長によつて螢
光寿命が異なる場合であつても、波長毎の螢光寿命
τ１、τ２を正確に求めることができる。 なお、前記実施例においては、いずれも、試料10の測
定位置を２次元方向に移動するための移動手段として、
Ｘ−Ｙステージ16が用いられていたが、試料測定位置を
２次元方向に移動するための移動手段はこれに限定され
ない。例えば、試料10がベルトコンベア等の上を流れて
いる場合には、光源12を該ベルトコンベアの流れ方向と
直交する１次元方向に移動する手段とすることができ
る。又、機械的な走査手段によらず、光束を電気光学的
に偏向して走査する構成としたり、光束走査と試料移動
を組合わせたりしてもよい。 更に、前記高速光検出器20又は分光器60の入力結増面
に、第１図や第４図に破線で示す如く、アパーチヤ62を
設けて共焦点光学系とすることにより、合焦点面毎の情
報を得るようにして、走査方向（２次元方向）だけでな
く、試料の深さ方向にも分解能を持たせることができ
る。 又、第６図に示す第３実施例の如く、前記変調光源12
とは別に落射照明光源80を設けて、例えばレンズ80Aを
介して試料10を照射し、この反射光をミラー82A及びレ
ンズ82CでTVカメラ84に導き、該TVカメラ84で反射画像
を撮像し、A/D変換器86でA/D変換後、信号処理装置22に
入力し、これを画像メモリ（図示省略）に記憶し、画像
表示装置24上に画像を表示して、試料10上の変調光の位
置の確認や、測定領域の状態をモニタすることもでき
る。 又、この反射画像とフオトルミネツセンスの寿命分布
画像、強度分布画像等を重ねて表示することも可能であ
る。 又、前記落射照明光源80に、試料10の吸収波長に合わ
せた波長フイルタ80Bを設け、試料10を全面照射して、
その時発生するフオトルミネツセンス像を所定の波長フ
イルタ82Bを介して、前記TVカメラ84により撮像し、２
次元のフオトルミネツセンス強度分布を求めることも可
能である。 更に、試料10の裏面側に透過照明のための光源90、レ
ンズ90A、90C及び波長フイルタ90Bを設け、試料10の透
過光による画像を前記TVカメラ84又は高速光検出器20に
より取得して、フオトルミネツセンスの寿命、強度分布
画像と比較することも可能である。この時、高速光検出
器20の前に設けられた分光器60により、試料10の非線形
性による第２高調波（SHG）成分を抽出し、試料10を走
査して非線形光学特性画像を得ることもできる。 なお、前記実施例においては、いずれも、本発明が半
導体ウエハの欠陥を検査するための半導体ウエハ評価装
置に適用されていたが、本発明の適用範囲はこれに限定
されず、他の半導体の螢光特性を検査するための装置に
も同様に適用できることは明らかである。An embodiment of a fluorescent characteristic inspection device according to the present invention applied to a semiconductor wafer evaluation device will be described in detail below with reference to the drawings. The first embodiment of the present invention is, as shown in FIG. 1, a modulation light source 12 for generating a sine wave intensity-modulated light for exciting a sample 10 such as a GaAs semiconductor wafer, and the modulation light source 12.
Irradiation optical system 14 for irradiating the sample 10 with the light of
An XY stage 16 for moving the measurement position (light irradiation position) of the sample 10 in the two-dimensional direction by moving the position of the sample 10 with respect to the two-dimensional direction, and a photo generated from the sample 10 A beam splitter 18A for extracting the luminescence and guiding it to the detector, a focusing optical system 18 including a filter 18B and a lens 18C for extracting the wavelength component of the photoluminescence, and the photoluminescence. To move the XY stage 16 and the phase detector 21 for detecting the phase difference between the phase of the light emission of the modulated light source 12 and the output signal of the high-speed photodetector. Therefore, while moving the sample measurement position in the two-dimensional direction, for example, the phase difference at each lattice-shaped measurement point (see FIG. 2) is analyzed and processed to determine the spatial intensity distribution of photoluminescence and Lifespan distribution, or The signal processing device 22 for obtaining the function distribution and the image display device 24 for displaying the spatial intensity distribution image and the lifetime distribution image obtained by the signal processing device 22 or the correlation distribution image thereof. . As the modulation light source 12, for example, a laser diode (LD) or a light emitting diode (LED) that can stably oscillate a sine wave intensity-modulated light having a wavelength of about 600 to 680 nm can be used. As a method of detecting the light emission of the modulation light source 12, for example, the light from the modulation light source 12 can be branched and one of the lights can be converted into an electric signal by a high-speed photodiode such as an avalanche photodiode (APD). . As the high-speed photodetector 20, for example, a high-speed photodiode or a photomultiplier tube can be used to simplify the structure. The analysis and processing of the information regarding the fluorescent waveform in the signal processing device 22 is performed as follows. When the sample 10 is excited with a sine wave l (t) represented by the following equation by modulating the excitation light with a sine wave, the fluorescence waveform f (t) has a phase of φ = tan −1 (ωτ ) Becomes a sine wave that is offset by only. The intensity of photoluminescence is also obtained from the average power of the fluorescent waveform f (t). l (t) = L 1 · sin (ωτ) + L 0 (1) The fluorescence lifetime and fluorescence intensity obtained in this way are
It is displayed as a spatial distribution image on the image display device 24. FIG. 3 shows an example of the fluorescent life display image. In FIG. 3, the distribution of the fluorescence lifetime τ is represented by, for example, the shade. When the fluorescence intensity and the lifetime are imaged, it is possible to display not only the black and white density but also the color image with different colors or three-dimensional display. or,
When the fluorescence lifetime also includes the second-order component τ 2 and the third-order component τ 3 , for example, only the first-order component τ 1 is mapped with green,
Map the first and second order components τ 1 , τ 2 in red and
The second, third and third order components τ 1 , τ 2 , τ 3 can be mapped in yellow. In addition, a primary component τ 1 and red, the second order component τ 2 and green, the third-order component τ 3 and blue, Yotsute to be superimposed sequentially. As a result, the primary component τ 1 red, secondary It is also possible to display the component τ 2 in yellow and the third-order component τ 3 in white. Furthermore, when displaying an image, smoothing processing may be appropriately performed to make the image easier to see. Further, the signal processing device 22 can also perform a calculation such as obtaining a correlation, for example, a ratio between different intensity distribution images and life distribution images, and display the calculation result (that is, the correlation distribution image). Next, the first embodiment of the present invention will be described in detail with reference to FIG. The second embodiment is similar to the first embodiment in that the modulation light source 12, the irradiation optical system 14, the XY stage 16, the condensing optical system 18, the high-speed photodetector 20, and the phase comparison are performed. In the semiconductor wafer evaluation device including the device 21, the signal processing device 22, and the image display device 24, further immediately before the high-speed photodetector 20,
A spectroscope 60 for dispersing photoluminescence generated from the sample 10 is provided, and the high-speed photodetector 20 detects a fluorescence waveform for each wavelength, and a spatial intensity distribution image and lifetime distribution image for each wavelength, Alternatively, the correlation distribution image thereof can be obtained. According to the second embodiment, the wavelength information can be measured at the same time, and, for example, as shown in FIG. 5, even if the fluorescence lifetime varies depending on the wavelength, the fluorescence lifetime τ 1 for each wavelength. , Τ 2 can be accurately obtained. In each of the above examples, as a moving means for moving the measurement position of the sample 10 in the two-dimensional direction,
Although the XY stage 16 is used, the moving means for moving the sample measurement position in the two-dimensional direction is not limited to this. For example, when the sample 10 is flowing on a belt conveyor or the like, the light source 12 can be a means for moving in a one-dimensional direction orthogonal to the flow direction of the belt conveyor. Further, instead of using a mechanical scanning means, the light beam may be electro-optically deflected for scanning, or the light beam scanning and the sample movement may be combined. Further, as shown by the broken line in FIGS. 1 and 4, an aperture 62 is provided on the input-increasing surface of the high-speed photodetector 20 or the spectroscope 60 to form a confocal optical system. By obtaining the information of 1, the resolution can be provided not only in the scanning direction (two-dimensional direction) but also in the depth direction of the sample. Also, as in the third embodiment shown in FIG.
In addition to the epi-illumination light source 80, for example, the sample 10 is irradiated through the lens 80A, the reflected light is guided to the TV camera 84 by the mirror 82A and the lens 82C, the reflected image is captured by the TV camera 84, After A / D conversion by the A / D converter 86, the signal is input to the signal processing device 22, stored in an image memory (not shown), an image is displayed on the image display device 24, and modulation is performed on the sample 10. It is also possible to confirm the position of light and monitor the state of the measurement area. Further, it is also possible to superimpose and display the reflection image, the photoluminescence lifetime distribution image, the intensity distribution image, and the like. Further, the epi-illumination light source 80 is provided with a wavelength filter 80B matched to the absorption wavelength of the sample 10, and the entire surface of the sample 10 is irradiated,
The photoluminescence image generated at that time is captured by the TV camera 84 through a predetermined wavelength filter 82B, and
It is also possible to obtain a three-dimensional photoluminescence intensity distribution. Further, a light source 90 for transmitted illumination, a lens 90A, a 90C and a wavelength filter 90B are provided on the back side of the sample 10, and an image by the transmitted light of the sample 10 is acquired by the TV camera 84 or the high-speed photodetector 20, It is also possible to compare the life and intensity distribution images of photoluminescence. At this time, the spectroscope 60 provided in front of the high-speed photodetector 20 extracts the second harmonic (SHG) component due to the non-linearity of the sample 10 and scans the sample 10 to obtain a non-linear optical characteristic image. You can also In each of the above embodiments, the present invention was applied to the semiconductor wafer evaluation apparatus for inspecting the semiconductor wafer for defects, but the scope of application of the present invention is not limited to this, and other semiconductors may be used. Obviously, it is likewise applicable to a device for inspecting fluorescence properties.
第１図は、本発明に係る半導体試料の螢光特性検査装置
の第１実施例の構成を示すブロツク線図、 第２図は、第１実施例における試料表面上の測定点の一
例を示す平面図、 第３図は、螢光寿命の空間的な分布の表示例を示す平面
図、 第４図は、本発明の第２実施例の構成を示すブロツク線
図、 第５図は、第２実施例によつて測定可能な螢光寿命の波
長依存性の例を示す線図、 第６図は、本発明の第３実施例の構成を示すブロツク線
図、 第７図は、半導体ウエハの品質と螢光波形の関係の例を
示す線図である。 10……試料、 12……変調光源、 14……照射光学系、 16……Ｘ−Ｙステージ、 18……集光光学系、 18B……フイルタ、 20……高速光検出器、 21……位相比較器、 22……信号処理装置、 24……画像表示装置、 60……分光器、 62……アパーチヤ、 80……落射照明電源、 80B、82B……波長フイルタ、 84……TVカメラ、 90……透過照明光源。FIG. 1 is a block diagram showing the configuration of the first embodiment of the fluorescence characteristic inspection apparatus for semiconductor samples according to the present invention, and FIG. 2 shows an example of measurement points on the sample surface in the first embodiment. 3 is a plan view, FIG. 3 is a plan view showing a display example of spatial distribution of fluorescence lifetime, FIG. 4 is a block diagram showing a configuration of a second embodiment of the present invention, and FIG. 2 is a diagram showing an example of the wavelength dependence of fluorescence lifetime measurable according to the second embodiment, FIG. 6 is a block diagram showing the constitution of the third embodiment of the present invention, and FIG. 7 is a semiconductor wafer. FIG. 6 is a diagram showing an example of the relationship between the quality of the image and the fluorescent waveform. 10 …… Sample, 12 …… Modulated light source, 14 …… Irradiation optical system, 16 …… XY stage, 18 …… Condensing optical system, 18B …… Filter, 20 …… High-speed photodetector, 21 …… Phase comparator, 22 …… Signal processing device, 24 …… Image display device, 60 …… Spectroscope, 62 …… Aperture, 80 …… Epi-illumination power supply, 80B, 82B …… Wavelength filter, 84 …… TV camera, 90: Transmitted illumination light source.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 水島 宜彦 静岡県浜松市市野町1126番地の１ 浜松 ホトニクス株式会社内 (56)参考文献 特開 昭63−312649（ＪＰ，Ａ) 特開 昭63−298211（ＪＰ，Ａ) 特公 昭49−43226（ＪＰ，Ｂ１) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiko Mizushima 1 126-1, Nomachi, Hamamatsu, Shizuoka Prefecture Hamamatsu Photonics Co., Ltd. (56) References JP 63-312649 (JP, A) JP 63- 298211 (JP, A) JP-B-49-43226 (JP, B1)
Claims (6)
に強度変調された光を発生する変調光源と、 該変調光源の光を試料に照射する照射光学系と、 試料の測定位置を２次元方向に移動するための移動手段
と、 試料から発生するフオトルミネツセンスを抽出して検出
器に導く集光光学系と、 前記フオトルミネツセンスを検出するための高速光検出
器と、 前記変調光源の発光の位相と高速光検出器の出力信号の
位相差を求める位相比較器と、 試料測定位置を２次元方向に移動しながら、各測定点に
おける前記位相差を解析・処理して、フオトルミネツセ
ンスの空間的な強度分布や寿命分布、又はその相関分布
を求める信号処理装置と、 該信号処理装置によつて得られたフオトミネツセンスの
強度分布や寿命分布画像を表示する画像表示装置と、 を含む半導体試料の螢光特性検査装置であつて、 前記高速光検出器の入力画像面にアパーチヤが設けら
れ、試料深さ方向の分解能を有する共焦点光学系とされ
ていることを特徴とする半導体試料の螢光特性検査装
置。1. A modulated light source for exciting a sample to generate light whose intensity is continuously and periodically modulated, an irradiation optical system for irradiating the sample with the light of the modulated light source, and a measurement position of the sample. Moving means for moving in two dimensions, a focusing optical system for extracting photoluminescence generated from a sample and guiding it to a detector, and a high-speed photodetector for detecting the photoluminescence, A phase comparator for determining the phase difference between the phase of the light emission of the modulated light source and the output signal of the high-speed photodetector, and analyzing and processing the phase difference at each measurement point while moving the sample measurement position in the two-dimensional direction. , A signal processing device for obtaining a spatial intensity distribution and life distribution of photoluminescence or its correlation distribution, and an intensity distribution and life distribution image of photoluminescence obtained by the signal processing device are displayed. Image display device And a semiconductor sample fluorescence characteristic inspecting device, comprising an aperture on the input image surface of the high-speed photodetector, which is a confocal optical system having a resolution in the depth direction of the sample. Fluorescence characteristic inspection device for semiconductor samples.
前に分光手段が設けられ、波長毎の空間的な強度分布や
寿命分布、又はその相関分布が求められることを特徴と
する半導体試料の螢光特性検査装置。2. A semiconductor sample according to claim 1, wherein a spectroscopic means is provided immediately before the high-speed photodetector, and a spatial intensity distribution and lifetime distribution for each wavelength or its correlation distribution are obtained. Fluorescence characteristic inspection device.
強度分布や寿命分布画像と重畳して、前記画像表示装置
に表示することを特徴とする半導体試料の螢光特性検査
装置。3. The image captured by the TV camera according to claim 1, further comprising an epi-illumination light source that illuminates the sample separately from the modulation light source, and a TV camera that guides reflected light from the sample. Is superimposed on the intensity distribution and lifetime distribution image of the photoluminescence and is displayed on the image display device.
料の吸収波長に合わせた波長フイルタを設け、試料を全
面照射して、発生するフオトルミネツセンス画像を所定
の波長フイルタを介して、前記TVカメラにより撮像し、
２次元のフオトミネツセンス強度分布を求めることを特
徴とする半導体試料の螢光特性検査装置。4. The wavelength illuminator according to claim 3, wherein the epi-illumination light source is provided with a wavelength filter matched to the absorption wavelength of the sample, and the entire surface of the sample is irradiated to generate a photoluminescence image through a predetermined wavelength filter. Imaged by the TV camera,
An apparatus for inspecting fluorescence characteristics of a semiconductor sample, characterized by obtaining a two-dimensional photoluminescence intensity distribution.
更に、試料の裏面側に透過照明のための光源及び光学系
を設け、試料の透過画像をTVカメラ又は高速光検出器に
より取得して、フオトルミネツセンスの強度分布や寿命
分布画像と重畳表示することを特徴とする半導体試料の
螢光特性検査装置。5. The method according to any one of claims 1 to 4,
In addition, a light source and an optical system for transmitted illumination are installed on the back side of the sample, and the transmitted image of the sample is acquired by a TV camera or high-speed photodetector, and the intensity distribution of the photoluminescence and the life distribution image are superimposed and displayed. An apparatus for inspecting a fluorescent property of a semiconductor sample, which is characterized by:
に設けられた分光手段により、試料の非線形性による第
２高調波成分を抽出し、試料を走査して非線形光学特性
画像を得ることを特徴とする半導体試料の螢光特性検査
装置。6. The non-linear optical characteristic image according to claim 5, wherein the spectroscopic means provided in front of the high-speed photodetector extracts the second harmonic component due to the non-linearity of the sample and scans the sample. An apparatus for inspecting fluorescence characteristics of a semiconductor sample, which is characterized in that
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1089480A JP2525894B2 (en) | 1989-04-07 | 1989-04-07 | Fluorescence characteristic inspection device for semiconductor samples |
| GB9007810A GB2231958A (en) | 1989-04-07 | 1990-04-06 | Measuring fluorescence characteristics |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1089480A JP2525894B2 (en) | 1989-04-07 | 1989-04-07 | Fluorescence characteristic inspection device for semiconductor samples |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02268256A JPH02268256A (en) | 1990-11-01 |
| JP2525894B2 true JP2525894B2 (en) | 1996-08-21 |
Family
ID=13971903
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1089480A Expired - Fee Related JP2525894B2 (en) | 1989-04-07 | 1989-04-07 | Fluorescence characteristic inspection device for semiconductor samples |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2525894B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5850447B1 (en) * | 2015-04-06 | 2016-02-03 | レーザーテック株式会社 | Inspection device |
| KR101861919B1 (en) * | 2016-06-16 | 2018-05-28 | 한국과학기술원 | Rapid optical inspection method of semiconductor |
| KR20190034795A (en) * | 2017-09-25 | 2019-04-03 | (주)엘립소테크놀러지 | Apparatus for inspecting surfaceusing using spectroscopic ellipsometer |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2728796B2 (en) * | 1991-04-24 | 1998-03-18 | 日立化成工業株式会社 | Chemiluminescence measuring method and measuring device |
| AU1130797A (en) * | 1995-08-24 | 1997-03-19 | Purdue Research Foundation | Fluorescence lifetime-based imaging and spectroscopy in tissues and other random media |
| US7328059B2 (en) | 1996-08-23 | 2008-02-05 | The Texas A & M University System | Imaging of light scattering tissues with fluorescent contrast agents |
| US7865230B1 (en) | 1997-02-07 | 2011-01-04 | Texas A&M University System | Method and system for detecting sentinel lymph nodes |
| US7054002B1 (en) | 1999-10-08 | 2006-05-30 | The Texas A&M University System | Characterization of luminescence in a scattering medium |
| CA2533621C (en) | 2003-06-20 | 2013-12-10 | The Texas A & M University System | Method and system for near-infrared fluorescence contrast-enhanced imaging with area illumination and area detection |
| JP5077872B2 (en) * | 2007-03-13 | 2012-11-21 | 独立行政法人 宇宙航空研究開発機構 | Defect inspection apparatus and method by photoluminescence of solar cell |
| DE102007057011B4 (en) * | 2007-11-23 | 2011-04-28 | Pi Photovoltaik-Institut Berlin Ag | Detecting device and method for detecting damage of a solar cell by means of photoluminescence |
| DE102010011066B4 (en) * | 2010-03-11 | 2020-10-22 | Pi4_Robotics Gmbh | Photovoltaic module or photovoltaic cell or semiconductor component identification method and photovoltaic module or photovoltaic cell or semiconductor component identification device |
| FR3054321B1 (en) * | 2016-07-25 | 2018-10-05 | Centre National De La Recherche Scientifique - Cnrs - | SYSTEM AND METHOD FOR MEASURING A PHYSICAL PARAMETER OF A MEDIUM |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5633722B2 (en) * | 1972-08-31 | 1981-08-05 | ||
| NL8700612A (en) * | 1987-03-13 | 1988-10-03 | Tno | CONFOCAL LASER SCANNING MICROSCOPE. |
| JPS63312649A (en) * | 1987-06-16 | 1988-12-21 | Kawasaki Steel Corp | Simultaneously measuring method for impurity level and carrier life in semiconductor |
-
1989
- 1989-04-07 JP JP1089480A patent/JP2525894B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5850447B1 (en) * | 2015-04-06 | 2016-02-03 | レーザーテック株式会社 | Inspection device |
| KR101861919B1 (en) * | 2016-06-16 | 2018-05-28 | 한국과학기술원 | Rapid optical inspection method of semiconductor |
| KR20190034795A (en) * | 2017-09-25 | 2019-04-03 | (주)엘립소테크놀러지 | Apparatus for inspecting surfaceusing using spectroscopic ellipsometer |
| KR102015811B1 (en) * | 2017-09-25 | 2019-08-29 | (주)엘립소테크놀러지 | Apparatus for inspecting surfaceusing using spectroscopic ellipsometer |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02268256A (en) | 1990-11-01 |
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