JPH02268256A - Apparatus for inspecting fluorescence characteristic - Google Patents
Apparatus for inspecting fluorescence characteristicInfo
- Publication number
- JPH02268256A JPH02268256A JP8948089A JP8948089A JPH02268256A JP H02268256 A JPH02268256 A JP H02268256A JP 8948089 A JP8948089 A JP 8948089A JP 8948089 A JP8948089 A JP 8948089A JP H02268256 A JPH02268256 A JP H02268256A
- Authority
- JP
- Japan
- Prior art keywords
- sample
- light
- moving
- light source
- photoluminescence
- 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.)
- Granted
Links
- 238000009826 distribution Methods 0.000 claims abstract description 45
- 238000005424 photoluminescence Methods 0.000 claims abstract description 26
- 238000012545 processing Methods 0.000 claims abstract description 13
- 238000005259 measurement Methods 0.000 claims description 25
- 238000012360 testing method Methods 0.000 claims description 14
- 230000003287 optical effect Effects 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 7
- 238000003384 imaging method Methods 0.000 claims description 4
- 230000001678 irradiating effect Effects 0.000 claims 1
- 229910001218 Gallium arsenide Inorganic materials 0.000 abstract description 5
- 230000007547 defect Effects 0.000 abstract description 5
- 238000004458 analytical method Methods 0.000 abstract description 2
- 235000012431 wafers Nutrition 0.000 description 14
- 239000004065 semiconductor Substances 0.000 description 9
- 239000013078 crystal Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 3
- 238000005286 illumination Methods 0.000 description 3
- 230000006798 recombination Effects 0.000 description 3
- 238000005215 recombination Methods 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 2
- 239000003814 drug Substances 0.000 description 2
- 229940079593 drug Drugs 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 238000004381 surface treatment Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 230000005669 field effect Effects 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000013507 mapping Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
Landscapes
- Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
Abstract
Description
本発明は、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） 、フォ
トダイオード（ＰＤ）、光学電気集積素子（ＯＥＩＧ）
、集積素子（ＩＣ）等に使用されるＱａ ＡＳウェハ等
の半導体ウェ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ォトルミネッセンスの空間的な強
度分布像及び寿命分布像又はその相関分布像を得ること
が可能な螢光特性検査装置に関するものである。
［従来の技術Ｉ
ＬＥＤ、ＬＤ、ＦＥＴ、ＰＤ、ＯＥ ＩＣ，ＩＣ等の製
造に用いられるＧａＡｓウェハの品質は、これらの製造
業者にとっ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、この発光がフォトルミネッセンスと呼
ばれている。このフォトルミネッ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、疵等によっ
ても決まる。従って、研磨→エツチングと加工工程が進
むに従って、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
ウェハは、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、品質の低いウェハは、同じく第７図に実
線Ｂで示す如く、螢光寿命が短くなっている。従って、
Ｇａ Ａｓウェ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、Ｇａ Ａｓウェハの品質は、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。The present invention relates to an apparatus for testing the fluorescent properties of a sample, and in particular, a light emitting diode (LED), a laser diode (LD), a field effect transistor (FET), a photodiode (PD), an optoelectrical integrated device ( OEIG)
, spatial intensity distribution image and lifetime distribution image of photoluminescence generated from a sample, suitable for use in evaluating the quality of semiconductor wafers such as Qa AS wafers used in integrated devices (ICs), etc. The present invention relates to a fluorescent property inspection device capable of obtaining a correlation distribution image. [Prior Art I] The quality of GaAs wafers used in the manufacture of LEDs, LDs, FETs, PDs, OE ICs, ICs, etc. is the biggest problem for these manufacturers, and cannot be guaranteed at present. In general, when a semiconductor crystal is irradiated with a light beam with energy greater than the forbidden band width to excite electrons from the valence band, fluorescence is observed as the excited electrons lose energy through recombination, and this light emission occurs. is called photoluminescence. The lifetime of the fluorescence in this photoluminescence is also determined by the quality of the crystal, surface treatment, surface distortion, flaws, etc. Therefore, as the processing process progresses from polishing to etching, the number of recombination centers on the surface decreases and the lifetime of the fluorescence may become longer. This corresponds to looking at the surface recombination rate. In general, the fluorescence lifespan changes due to the effects of crystal quality, crystal defects, surface conditions, surface treatment, etc., and wafers with good conditions, that is, good quality, are While the fluorescent life is longer as shown by the solid line A in the figure, lower quality wafers have a shorter fluorescent life as shown by the solid line B in FIG. Therefore,
When evaluating the quality of GaAs wafers, it is important to measure their fluorescence lifetime. In addition, the quality of GaAs wafers is determined not only by the fluorescence lifetime but also by
Fluorescence efficiency (quantum efficiency, absolute value of fluorescence, ie, fluorescence intensity) is also important. Normally, as shown in FIG. 7, there is a correlation between fluorescence efficiency and lifetime, but this may not always be the case, so it is also important to measure the fluorescence intensity.
しかしながら、フォトルミネッ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）
のフォトルミネッセンスの強度分布から、試料の評価を
行うものであった。
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、発生したフォトルミネッセンスの螢光寿命を測定
する技術も提案されている。
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ォトルミネッセンスの螢光強
度及び螢光寿命、又はその相関の空間的な分布像を高速
で得ることが可能な螢光特性検査装置を提供することを
課題とする。
（課題を達成するための手段１
本発明は、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を励起するための強度
変調された光源１２と、該光源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から発生するフォトルミネッセンスを抽出して検
出器に導く集光光学系１８と、前記フォトルミネッセン
スを検出するための高速光検出器２０と、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、フォトル
ミネッ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とを備えることに
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２０を、高速フォトダイオードや
光電子増倍管としたものである。
又、前記測定位置の移動手段を、試料を機械的に移動す
るものとしたものである。
又、前記測定位置の移動手段を、前記光源からの光を走
査するものとしたものである。
又、前記測定位置の移動手段を、試料を機械的に移動し
、且つ、光源からの光を走査するものとしたものである
。
又、前記高速光検出器の前に分光手段を設け、波長毎の
空間的な強度分布及び寿命分布、又はその相関分布が求
められるようにしたものである。
又、前記高速光検出器又は分光手段の入力結像面にアパ
ーチャを設け、試料深さ方向の分解能を有するようにし
たものである。However, conventional equipment for examining the quality of crystals using photoluminescence irradiates a sample with continuous light (DC light) of wavelength λ1, and generates a wavelength of λ2 (>λ1).
The sample was evaluated based on the intensity distribution of photoluminescence. A technique has also been proposed in which a sample is irradiated with pulsed light from a mode-locked pulsed laser or a semiconductor laser, and the fluorescence lifetime of the generated photoluminescence is measured using a sampling streak camera. However, since measurement results can only be obtained from a single measurement point, there have been problems such as difficulty in detecting local defects. The present invention was made to solve the above-mentioned conventional problems, and it is possible to quickly obtain a spatial distribution image of the fluorescence intensity and fluorescence lifetime of photoluminescence generated from a sample, or the correlation thereof. An object of the present invention is to provide a fluorescent property testing device. (Means for Achieving the Object 1) The present invention provides a fluorescence property testing apparatus, which includes an intensity-modulated light source 12 for exciting a sample 10, and a An irradiation optical system 14 that irradiates the sample 10 with light, a moving means (X-Y stage 16 in the figure) for moving the measurement position of the sample 10, and a detector that extracts photoluminescence generated from the sample 10. a high-speed photodetector 20 for detecting the photoluminescence; a phase comparator 21 for determining the phase difference between the phase of light emission from the light source 12 and the output signal of the high-speed photodetector 20; By comprising a signal processing device 22 that analyzes and processes the phase difference at each measurement point while moving the sample measurement position to obtain the spatial intensity distribution and lifetime distribution of photoluminescence, or the correlation distribution thereof, The above-mentioned problem has been achieved. Also, the high-speed photodetector 20 is a high-speed photodiode or a photomultiplier tube. Also, the measuring position moving means is a method for mechanically moving the sample. Further, the means for moving the measurement position is configured to scan the light from the light source.The means for moving the measurement position is configured to mechanically move the sample, In addition, the light from the light source is scanned. Also, a spectroscopic means is provided in front of the high-speed photodetector, and the spatial intensity distribution and lifetime distribution for each wavelength or their correlation distribution are determined. Furthermore, an aperture is provided on the input imaging plane of the high-speed photodetector or spectroscopic means to provide resolution in the depth direction of the sample.
【作用及び効果］
本発明にかかる螢光特性検査装置では、強度変調された
光源１２を用いて試料１０を励起し、該光ａｉ１２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、フォトルミネッセンスの空間
的な強度分布及び寿命分布、又はその相関分布を求める
ようにしている。従って、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ウェハ等の品
質を正確に評価することが可能となる。更に、該螢光強
度及び寿命、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。
又、前記高速光検出器２０を高速フォトダイオードや光
電子増倍管とした場合には、構成が簡略である。
又、前記測定位置の移動手段を、試料を機械的に移動す
るものとした場合には、光学系を走査する必要がなく、
光学系に最も有利な条件で測定することができる。
又、前記測定位置の移動手段を、光源からの光を走査す
るものとした場合には、試料を移動する必要がなく、高
速走査が可能である。
又、前記測定位置の移動手段を、試料を機械的に移動し
、且つ、光源からの光を走査するものとした場合には、
例えば、それぞれを互いに直交する１次元方向に走査す
ることによって、２次元方向の走査が可能となる。
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、フォトルミネッセンスの波長毎の空間的な強度
分布及び寿命分布、又はその相関分布を得ることが可能
となり、特に、波長によって螢光寿命が異なる試料を検
査する際に好適である。
又、前記高速光検出器２０又は分光手段の入力結像面に
アパーチャを設けた場合には、共焦点系となり、合焦点
面の情報だけ得られるので、試料深さ方向についても分
解能が得られる。
【実施例】
以下図面を参照して、半導体ウェ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
半導体ウェハ等の試料１０を励起するための強度変調さ
れた光源１２と、該光源１２の光を試料１０に照射する
照射光学系１４と、前記光源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って、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から発生するフォトル
ミネッセンスを抽出して検出器に導くための、ビームス
プリッタ１８Ａ１フオトルミネツセンスの波長成分を抽
出するためのフィルタ１８Ｂ及びレンズ１８Ｇを含む集
光光学系１８と、前記フォトルミネッセンスを検出する
ための高速光検出器２０と、前記光１１１１２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１′６を移動すること
によって、試料測定位置を移動しながら、例えば格子状
の各測定点く第２図参照）における前記位相差を解析、
処理して、フォトルミネッ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袋！２
２と、該信号処理装置２２によって得られた空間的な強
度分布像及び寿命分布像、又はその相関分布像を表示す
る表示装置２４とから構成されている。
前記光源１２としては、例えば波長６００〜６８Ｑｎｍ
程度の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。眼光１Ｉｉ１２の発光を検出する方法
としては、例えば光源１２からの光を分岐し、その一方
の光をアバランシュフォトダイオード（ＡＰＤ）等の高
速フォトダイオードで電気信号に変換することができる
。
前記高速光検出器２０としては、例えば高速フォトダイ
オードや光電子増倍管を用いることができる。
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って、試料１０を次
式で示される正弦波λ（１）で励起すると、その螢光波
形ｆ（ｔ）は、位相がφ−ｔ ａ ｎ ’（ωτ）だけ
ずれた正弦波となる。又、フォトルミネッセンスの強度
も螢光波形ｒ（ｔ）の平均パワーから求められる。
Ｊ２＝ （ｔ ）−Ｌｌｓｉｒｒ（ωｔ ） ＋ Ｌ
ｏ −（１）このようにして求められた螢光寿命及び螢
光強度が、前記表示装置２４に空間的分布像として表示
される。螢光寿命の表示像の一例を第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
よって表わされている。
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機成分τ２、第３火成分τ３もある場合
には、例えば１次式分τ１のみを緑でマツピングし、１
次及び２次式分τ１、τ２を赤でマツピングし、１次、
２次及び３次式分τ１、τ２、τ３を黄でマツピングす
ることができる。又、１次式分τ１を赤とし、２次式分
τ２を緑とし、３次式分τ３を青とし、順次重ねること
によって、結果的に、１次式分τ１を赤、２次式分τ２
を黄、３次式分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
って、見易くすることも可能である。
又、信号処理装置２２は、異なる強度分布像及び寿命分
布像の間での相関、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２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、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２ｏと、位相比較器２１と、
信号処理装置２２と、表示装置２４とを備えた半導体ウ
ェ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から発生するフォトルミネッセンスを
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像
及び寿命分布像、又はその相関分布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、波長によって螢光
寿命が異なる場合であっても、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１
２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の入力結像
面に、第１図や第４図に破線で示す如く、アパーチャ６
２を設けて共焦点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、前記変調光の光５
！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、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、この反射画像とフォトルミネッ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
わせた波長フィルタ８０Ｂを設け、試料１０を全面照射
して、その時発生するフォトルミネッセンス像を所定の
波長フィルタ８２Ｂを介して、前記ＴＶカメラ８４によ
り撮像し、２次元のフォトルミネッ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及び波長フィルタ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、フォトルミネッセン
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手段６
０により、試料１ｏの非線形性による第２高調波（ＳＨ
Ｇ）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。
又、前記実施例においては、いずれも、本発明が半導体
ウェハの欠陥を検査するための半導体ウェハ評価装置に
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、誘電体、螢光面、薬剤、組、生体検査等、他の螢光
特性を検査するための装置にも同様に通用できることは
明らかである。[Operations and Effects] In the fluorescent property testing device according to the present invention, the sample 10 is excited using the intensity-modulated light source 12, and the phase difference between the emission phase of the light ai12 and the output signal of the high-speed photodetector 20 is While moving the sample measurement position, the phase difference at each measurement point is analyzed and processed to obtain the spatial intensity distribution and lifetime distribution of photoluminescence, or their correlation distribution. Therefore, the fluorescence intensity and lifetime of the sample can be simultaneously measured at high speed, making it possible to accurately evaluate the quality of GaAs wafers and the like. Furthermore, since a spatial distribution image of the fluorescence intensity and lifetime or their correlation can be obtained, local defects etc. can be easily inspected. Further, when the high-speed photodetector 20 is a high-speed photodiode or a photomultiplier tube, the configuration is simple. Furthermore, when the means for moving the measurement position is one that moves the sample mechanically, there is no need to scan the optical system;
Measurements can be made under the most advantageous conditions for the optical system. Furthermore, if the means for moving the measurement position is one that scans light from a light source, there is no need to move the sample, and high-speed scanning is possible. Furthermore, when the means for moving the measurement position is one that mechanically moves the sample and scans the light from the light source,
For example, by scanning each in a one-dimensional direction orthogonal to each other, scanning in a two-dimensional direction becomes possible. Furthermore, when a spectroscopic means is provided immediately before the high-speed photodetector 20, it becomes possible to obtain the spatial intensity distribution and lifetime distribution for each wavelength of photoluminescence, or the correlation distribution thereof. This is suitable for inspecting samples with different fluorescence lifetimes. Furthermore, if an aperture is provided on the input imaging plane of the high-speed photodetector 20 or the spectroscopic means, it becomes a confocal system, and only information on the focused plane can be obtained, so resolution can also be obtained in the sample depth direction. . Embodiments Hereinafter, embodiments of the fluorescent property inspection apparatus according to the present invention applied to a semiconductor wafer evaluation apparatus will be described in detail with reference to the drawings. The first embodiment of the present invention, as shown in FIG.
An intensity-modulated light source 12 for exciting a sample 10 such as a semiconductor wafer, an irradiation optical system 14 that irradiates the sample 10 with light from the light source 12, and a position of the sample 10 relative to the light source 12 that moves in a two-dimensional direction. an X-Y stage 16 for moving the measurement position (light irradiation position) of the sample 10 in two-dimensional directions, and a beam splitter for extracting photoluminescence generated from the sample 10 and guiding it to a detector. A condensing optical system 18 including a filter 18B and a lens 18G for extracting the wavelength component of the 18A1 photoluminescence, a high-speed photodetector 20 for detecting the photoluminescence, and a phase of the emission of the light 11112. By moving the phase comparator 21 that determines the phase difference between the output signals of the high-speed photodetector and the X-Y stage 1'6, the sample measurement position is moved and the second Analyzing the phase difference in (see figure),
A signal processing bag that processes and calculates the spatial intensity distribution and lifetime distribution of photoluminescence, or their correlation distribution! 2
2, and a display device 24 that displays spatial intensity distribution images and lifetime distribution images obtained by the signal processing device 22, or their correlation distribution images. The light source 12 has a wavelength of 600 to 68 Qnm, for example.
A laser diode (LD) or a light emitting diode (LED) that can stably oscillate light whose intensity is modulated to a certain extent can be used. As a method for detecting the emission of the ocular light 1Ii12, for example, the light from the light source 12 can be split, and one of the lights can be converted into an electrical signal using 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. Analysis and processing of information regarding the fluorescence waveform in the signal processing device 22 is performed as follows. When the sample 10 is excited by a sine wave λ(1) expressed by the following equation by modulating the excitation light with a sine wave, the fluorescence waveform f(t) has a phase of φ−t a n ′(ωτ) The result is a sine wave that is shifted by The intensity of photoluminescence can also be determined from the average power of the fluorescence waveform r(t). J2=(t)−Llsirr(ωt)+L
o-(1) The fluorescence lifetime and fluorescence intensity thus determined are displayed on the display device 24 as a spatial distribution image. An example of a display image of the fluorescent life is shown in FIG. In FIG. 3, the distribution of the fluorescence lifetime τ is represented by, for example, shading. When visualizing the fluorescence intensity and lifespan, in addition to displaying in black and white density, it is also possible to display a color image with different colors, or to perform three-dimensional display. In addition, if the fluorescent life includes a second component τ2 and a third fire component τ3, for example, only the linear component τ1 is mapped in green, and 1
Mapping the following and quadratic equation components τ1 and τ2 in red, the first order,
The quadratic and cubic equation components τ1, τ2, and τ3 can be mapped in yellow. Also, by making the linear equation component τ1 red, the quadratic equation component τ2 green, and the cubic equation component τ3 blue, and sequentially overlapping them, the linear equation component τ1 becomes red and the quadratic equation component τ1 becomes red, and the quadratic equation component τ1 becomes red. τ2
It is also possible to display the cubic equation component τ3 in yellow and the cubic equation component τ3 in white. Furthermore, when displaying an image, it is possible to perform appropriate smoothing processing to make it easier to see. Further, the signal processing device 22 performs calculations such as calculating a correlation between different intensity distribution images and lifetime distribution images, for example, calculating a ratio.
It is also possible to display the calculation results (ie, the correlation distribution image). Next, a second embodiment of the present invention will be described in detail with reference to FIG. This second embodiment has a light source 12 similar to the first embodiment.
, an irradiation optical system 14, an X-Y stage 16, a condensing optical system 18, a high-speed photodetector 2o, a phase comparator 21,
In the semiconductor wafer evaluation apparatus equipped with a signal processing device 22 and a display device 24, a spectrometer 60 for separating photoluminescence generated from the sample 10 is further provided immediately before the high-speed photodetector 20 to perform high-speed photodetection. The device 20 detects the fluorescence waveform for each wavelength to obtain a spatial intensity distribution image, a lifetime distribution image, or a correlation distribution image for each wavelength. According to this second embodiment, wavelength information can also be measured at the same time. For example, as shown in FIG. 5, even if the fluorescent lifetime differs depending on the wavelength, the fluorescent lifetime τ1 for each wavelength,
τ2 can be determined accurately. In each of the above embodiments, the X-Y stage 16 was used as a moving means for moving the measurement position of the sample 10, but this is the moving means for moving the sample measurement position. Not limited. For example, sample 10
is flowing on a belt conveyor, etc., light source 1
2 can be a means for moving in a one-dimensional direction perpendicular to the flow direction of the belt conveyor. Furthermore, instead of using mechanical scanning means, a configuration may be adopted in which the beam is electro-optically deflected and scanned, or a beam scanning and sample movement may be combined. Furthermore, an aperture 6 is provided on the input imaging plane of the high-speed photodetector 20 or the spectrometer 60, as shown by broken lines in FIGS. 1 and 4.
2 to form a confocal system, it is possible to obtain information for each focal plane and provide resolution not only in the scanning direction (two-dimensional direction) but also in the depth direction of the sample. Further, as in the third embodiment shown in FIG. 6, the modulated light 5
! 12, an epi-illumination light source 80 is provided to illuminate the sample 10 through, for example, a lens 80A, and guide this reflected light to a TV camera 84 using a mirror 82A and a lens 82C, and the TV camera 84 captures a reflected image. , A/D converter 86
After A/D conversion, the signal is input to the signal processing device 22, stored in an image memory (not shown), and the image is displayed on the display device 24 to confirm the position of the modulated light on the sample 10 and perform measurements. It is also possible to monitor the state of the region. Further, it is also possible to display this reflection image, a photoluminescence lifetime distribution image, an intensity distribution image, etc. in an overlapping manner. Further, the epi-illumination light source 80 is provided with a wavelength filter 80B matching the absorption wavelength of the sample 10, and the entire surface of the sample 10 is irradiated, and the photoluminescence image generated at that time is transmitted to the TV camera through a predetermined wavelength filter 82B. It is also possible to take an image using 84 and obtain a two-dimensional photoluminescence intensity distribution. Furthermore, a light source 90 for transmitted illumination is provided on the back side of the sample 10,
Lenses 90A, 90C and wavelength filter 90B are provided,
It is also possible to obtain an image of the transmitted light of the sample 10 using the TV camera 84 or the high-speed photodetector 20 and compare it with the photoluminescence lifetime and intensity distribution image. At this time, the spectroscopic means 6 provided in front of the high-speed photodetector 20
0, the second harmonic (SH
G) It is also possible to extract the component and scan the sample 10 to obtain a nonlinear optical characteristic image. Furthermore, in each of the above embodiments, the present invention is applied to a semiconductor wafer evaluation device for inspecting semiconductor wafers for defects, but the scope of application of the present invention is not limited to this, and is applicable to dielectrics, fluorescent materials, etc. It is clear that the present invention can be similarly applied to devices for testing other fluorescent properties such as light surfaces, drugs, drugs, biological tests, etc.
第１図は、本発明に係る螢光特性検査装置の第１実施例
の構成を示すブロック線図、
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ック線
図、
第５図は、第２実施例によっ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ック線
図、
第７図は、半導体ウェ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・・・光源、
１４・・・照射光学系、
１６・・・Ｘ−Ｙステージ、
１８・・・集光光学系、
１８Ｂ・・・フィルタ、
２０・・・高速光検出器、
２１・・・位相比較器、
２２・・・信号処理装置、
６０・・・分光器、
６２・・・アパーチャ。FIG. 1 is a block diagram showing the configuration of a first embodiment of a fluorescent property testing device according to the present invention; FIG. 2 is a plan view showing an example of measurement points on a sample surface in the first embodiment; FIG. 3 is a plan view showing an example of displaying the spatial distribution of fluorescence lifetime, FIG. 4 is a block diagram showing the configuration of a second embodiment of the present invention, and FIG. 5 is a second embodiment. Fig. 6 is a block diagram showing the configuration of the third embodiment of the present invention; Fig. 7 shows the quality and fluorescence of semiconductor wafers. FIG. 3 is a diagram showing an example of a waveform relationship. DESCRIPTION OF SYMBOLS 10... Sample, 12... Light source, 14... Irradiation optical system, 16... X-Y stage, 18... Condensing optical system, 18B... Filter, 20... High speed light Detector, 21... Phase comparator, 22... Signal processing device, 60... Spectrometer, 62... Aperture.
Claims (7)
位置を移動するための移動手段と、試料から発生するフ
ォトルミネッセンスを抽出して検出器に導く集光光学系
と、 前記フォトルミネッセンスを検出するための高速光検出
器と、 前記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、フォトルミネッセンスの空間的
な強度分布及び寿命分布、又はその相関分布を求める信
号処理装置と、 を含むことを特徴とする螢光特性検査装置。(1) An intensity-modulated light source for exciting the sample, an irradiation optical system for irradiating the sample with light from the light source, a moving means for moving the measurement position of the sample, and a photoluminescence generator generated from the sample. a focusing optical system for extracting light and guiding it to a detector; a high-speed photodetector for detecting the photoluminescence; and a phase comparator for determining the phase difference between the phase of the light emission from the light source and the output signal of the high-speed photodetector. , a signal processing device that analyzes and processes the phase difference at each measurement point while moving the sample measurement position to obtain a spatial intensity distribution and lifetime distribution of photoluminescence, or a correlation distribution thereof; Features of fluorescent property testing equipment.
トダイオードや光電子増倍管であることを特徴とする螢
光特性検査装置。(2) A fluorescence characteristic testing device according to claim 1, wherein the high-speed photodetector is a high-speed photodiode or a photomultiplier tube.
試料を機械的に移動するものであることを特徴とする螢
光特性検査装置。(3) In claim 1, the means for moving the measurement position:
A fluorescent property testing device characterized by mechanically moving a sample.
前記光源からの光を走査するものであることを特徴とす
る螢光特性検査装置。(4) In claim 1, the means for moving the measurement position:
A fluorescent property testing device characterized in that it scans light from the light source.
試料を機械的に移動し、且つ、光源からの光を走査する
ものであることを特徴とする螢光特性検査装置。(5) In claim 1, the means for moving the measurement position:
A fluorescent property testing device characterized by mechanically moving a sample and scanning light from a light source.
手段が設けられ、波長毎の空間的な強度分布及び寿命分
布、又はその相関分布が求められることを特徴とする螢
光特性検査装置。(6) The fluorescent property test according to claim 1, characterized in that a spectroscopic means is provided in front of the high-speed photodetector, and a spatial intensity distribution and lifetime distribution for each wavelength, or a correlation distribution thereof, is determined. Device.
分光手段の入力結像面にアパーチャが設けられ、試料深
さ方向の分解能を有することを特徴とする螢光特性検査
装置。(7) A fluorescence characteristic testing device according to claim 1 or 6, characterized in that an aperture is provided on the input imaging plane of the high-speed photodetector or spectroscopic means, and has resolution in the depth direction of the sample.
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 true JPH02268256A (en) | 1990-11-01 |
| JP2525894B2 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 (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04324345A (en) * | 1991-04-24 | 1992-11-13 | Hitachi Chem Co Ltd | Method and apparatus for measuring chemiluminescence |
| WO1997008538A1 (en) * | 1995-08-24 | 1997-03-06 | Purdue Research Foundation | Fluorescence lifetime-based imaging and spectroscopy in tissues and other random media |
| US7054002B1 (en) | 1999-10-08 | 2006-05-30 | The Texas A&M University System | Characterization of luminescence in a scattering medium |
| US7328059B2 (en) | 1996-08-23 | 2008-02-05 | The Texas A & M University System | Imaging of light scattering tissues with fluorescent contrast agents |
| JP2008224432A (en) * | 2007-03-13 | 2008-09-25 | Japan Aerospace Exploration Agency | Defect inspection device and method by photo luminescence of solar battery |
| DE102007057011A1 (en) * | 2007-11-23 | 2009-06-10 | Pi Photovoltaik-Institut Berlin Ag | Detecting device for detecting damage of solar cell by photoluminescence, has radiation source which is formed to produce electromagnetic jets, particularly in visible wavelength area |
| US7599732B2 (en) | 2003-06-20 | 2009-10-06 | The Texas A&M University System | Method and system for near-infrared fluorescence contrast-enhanced imaging with area illumination and area detection |
| US7865230B1 (en) | 1997-02-07 | 2011-01-04 | Texas A&M University System | Method and system for detecting sentinel lymph nodes |
| DE102010011066A1 (en) * | 2010-03-11 | 2011-09-15 | Pi4_Robotics Gmbh | Method for identifying semiconductor component i.e. photovoltaic module, involves generating luminescence image by photovoltaic module or photovoltaic cell, and determining identification characteristic as marking from luminescence image |
| JP2019522210A (en) * | 2016-07-25 | 2019-08-08 | サントル、ナショナール、ド、ラ、ルシェルシュ、シアンティフィク、（セーエヌエルエス） | System and method for measuring physical parameters of a medium |
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| 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 |
| KR102015811B1 (en) * | 2017-09-25 | 2019-08-29 | (주)엘립소테크놀러지 | Apparatus for inspecting surfaceusing using spectroscopic ellipsometer |
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| JPS63312649A (en) * | 1987-06-16 | 1988-12-21 | Kawasaki Steel Corp | Simultaneously measuring method for impurity level and carrier life in semiconductor |
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Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04324345A (en) * | 1991-04-24 | 1992-11-13 | Hitachi Chem Co Ltd | Method and apparatus for measuring chemiluminescence |
| WO1997008538A1 (en) * | 1995-08-24 | 1997-03-06 | Purdue Research Foundation | Fluorescence lifetime-based imaging and spectroscopy in tissues and other random media |
| US5865754A (en) * | 1995-08-24 | 1999-02-02 | Purdue Research Foundation Office Of Technology Transfer | Fluorescence imaging system and method |
| 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 |
| US7599732B2 (en) | 2003-06-20 | 2009-10-06 | The Texas A&M University System | Method and system for near-infrared fluorescence contrast-enhanced imaging with area illumination and area detection |
| JP2008224432A (en) * | 2007-03-13 | 2008-09-25 | Japan Aerospace Exploration Agency | Defect inspection device and method by photo luminescence of solar battery |
| DE102007057011A1 (en) * | 2007-11-23 | 2009-06-10 | Pi Photovoltaik-Institut Berlin Ag | Detecting device for detecting damage of solar cell by photoluminescence, has radiation source which is formed to produce electromagnetic jets, particularly in visible wavelength area |
| 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 |
| DE102010011066A1 (en) * | 2010-03-11 | 2011-09-15 | Pi4_Robotics Gmbh | Method for identifying semiconductor component i.e. photovoltaic module, involves generating luminescence image by photovoltaic module or photovoltaic cell, and determining identification characteristic as marking from luminescence image |
| 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 |
| JP2019522210A (en) * | 2016-07-25 | 2019-08-08 | サントル、ナショナール、ド、ラ、ルシェルシュ、シアンティフィク、（セーエヌエルエス） | System and method for measuring physical parameters of a medium |
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